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The high incidence, death, disability, and recurrence of ischemic stroke (CIS) place a significant cost on families and society. According to recent research on the condition, immune-related damage is a major contributor to the development and occurrence of CIS. Innate immunity and adaptive immunity are the two primary categories of the immune system in the body. The body's first line of defense is innate immunity, and immune cells play a role in every stage of the immune system. At the same time, protein molecules play a vital function in regulating and differentiating immune cells. It can be said that protein molecules are the foundation of immune regulation. Model mice are necessary for us to examine fixed compounds in our studies. Conditional deletion and overexpression mouse models are the two primary categories of model mice. Numerous model mice have been documented in CIS research. The study of innate immune responses following ischemic stroke will benefit more from the use of these transgenic mice that target innate immunity. This paper analyzes the literature on transgenic mice related to innate immune responses following ischemic stroke because of the significance of these responses. It is anticipated to produce novel medications, improve clinical treatment guidance, and undergo a metamorphosis and application in the clinic in the future. [ABSTRACT FROM AUTHOR]

Complex neocortical functions rely on networks of diverse excitatory and inhibitory neurons. While local connectivity rules between major neuronal subclasses have been established, the specificity of connections at the level of transcriptomic subtypes remains unclear. We introduce single transcriptome assisted rabies tracing (START), a method combining monosynaptic rabies tracing and single-nuclei RNA sequencing to identify transcriptomic cell types, providing inputs to defined neuron populations. We employ START to transcriptomically characterize inhibitory neurons providing monosynaptic input to 5 different layer-specific excitatory cortical neuron populations in mouse primary visual cortex (V1). At the subclass level, we observe results consistent with findings from prior studies that resolve neuronal subclasses using antibody staining, transgenic mouse lines, and morphological reconstruction. With improved neuronal subtype granularity achieved with START, we demonstrate transcriptomic subtype specificity of inhibitory inputs to various excitatory neuron subclasses. These results establish local connectivity rules at the resolution of transcriptomic inhibitory cell types. • START combines monosynaptic rabies tracing with single-nucleus RNA sequencing • Local cortical circuit connectivity is transcriptomic subclass and subtype specific • Excitatory neurons receive selective input from subtypes of Sst/Pvalb/Vip/Lamp5 neurons • Transcriptomic characterization of inhibitory input neurons reveals new circuit motifs Patiño et al. introduce single transcriptome assisted rabies tracing (START), a new technical approach combining transsynaptic neuronal circuit mapping with transcriptomic classification to achieve precise neuronal characterization. Using START, they identify novel local cortical circuit connectivity motifs between inhibitory neuron subtypes and layer-specific excitatory subclasses. [ABSTRACT FROM AUTHOR]

Background: The age at onset (AO) of Machado-Joseph disease (SCA3/MJD), a disorder due to an expanded CAG repeat (CAGexp) in ATXN3, is quite variable and the role of environmental factors is still unknown. Caffeine was associated with protective effects against other neurodegenerative diseases, and against SCA3/MJD in transgenic mouse models. We aimed to evaluate whether caffeine consumption and its interaction with variants of caffeine signaling/metabolization genes impact the AO of this disease. Methods: a questionnaire on caffeine consumption was applied to adult patients and unrelated controls living in Rio Grande do Sul, Brazil. AO and CAGexp were previously determined. SNPs rs5751876 (ADORA2A), rs2298383 (ADORA2A), rs762551 (CYP1A2) and rs478597 (NOS1) were genotyped. AO of subgroups were compared, adjusting the CAGexp to 75 repeats (p < 0.05). Results: 171/179 cases and 98/100 controls consumed caffeine. Cases with high and low caffeine consumption (more or less than 314.5 mg of caffeine/day) had mean (SD) AO of 35.05 (11.44) and 35.43 (10.08) years (p = 0.40). The mean (SD) AO of the subgroups produced by the presence or absence of caffeine-enhancing alleles in ADORA2A (T allele at rs5751876 and rs2298383), CYP1A2 (C allele) and NOS1 (C allele) were all similar (p between 0.069 and 0.516). Discussion: Caffeine consumption was not related to changes in the AO of SCA3/MJD, either alone or in interaction with protective genotypes at ADORA2A, CYP1A2 and NOS1. [ABSTRACT FROM AUTHOR]

The generation and maintenance of memory T cells are regulated by various factors, including cytokines. Previous studies have shown that IL-27 is produced during the early acute phase of Plasmodium chabaudi chabaudi AS (Pcc) infection and inhibits the development of Th1-type memory CD4+ T cells. However, whether IL-27 acts directly on its receptor on Plasmodium -specific CD4+ T cells or indirectly via its receptor on other immune cells remains unclear. We aimed to determine the role of IL-27 receptor signaling in different immune cell types in regulating the generation and phenotype of memory CD4+ T cells during Plasmodium infection. We utilized Plasmodium -specific T-cell antigen receptor (TCR) transgenic mice, PbT-II, and Il27rα −/− mice to assess the direct and indirect effects of IL-27 signaling on memory CD4+ T-cell generation. Mice were transferred with PbT-II or Il27rα −/− PbT-II cells and infected with Pcc. Conditional knockout mice lacking the IL-27 receptor in T cells or dendritic cells were employed to discern the specific immune cell types involved in IL-27 receptor signaling. High levels of memory in PbT-II cells with Th1-shift occurred only when both PbT-II and host cells lacked the IL-27 receptor, suggesting the predominant inhibitory role of IL-27 signaling in both cell types. Furthermore, IL-27 receptor signaling in T cells limited the number of memory CD4+ T cells, while signaling in both T and dendritic cells contributed to the Th1 dominance of memory CD4+ T cells. These findings underscore the complex cytokine signaling network regulating memory CD4+ T cells during Plasmodium infection. [ABSTRACT FROM AUTHOR]

BAFF, a vital B cell survival and differentiation factor, has three receptors: B‐cell maturation antigen (BCMA), transmembrane activator and CAML interactor (TACI) and BR3. Although B cells are greatly reduced in B6.Baff−/− (which harbour no BAFF) and B6.Br3−/− mice (which harbour supra‐normal levels of BAFF), the distributions of B cell subsets and relationships between Foxp3+ and CD4+ cells in these mice differ. Using a large panel of B6 congenic knockout and/or transgenic mice, we demonstrate that (1) supra‐normal levels of BAFF per se do not explain the phenotypic differences between B6.Baff−/− and B6.Br3−/− mice; (2) B cells are expanded in B6.Taci−/− mice, with preferential expansion of follicular (FO) B cells at the expense of CD19+CD21−/loCD23−/lo B cells but without the preferential expansion of Foxp3+ cells observed in B6 mice bearing a Baff transgene; (3) despite no expansion in total B cells, percentages of FO B cells and marginal zone B cells are higher and percentages of CD19+CD21−/loCD23−/lo B cells are lower in young B6.Bcma−/− mice, consistent with the inability of B6.Br3−/−.Taci−/− mice to recapitulate the B cell profile of B6.Baff−/− mice; and (4) percentages of Foxp3+ cells in B6.Br3−/−.Taci−/− mice are intermediate between those in B6.Br3−/− and B6.Taci−/− mice despite the B cell profile of B6.Br3−/−.Taci−/− mice strongly resembling that of B6.Br3−/− mice. Collectively, our findings point to a non‐redundant role for each of the BAFF receptors in determining the ultimate lymphocyte profile of the host. This may have clinically relevant ramifications in that the degree that a candidate therapeutic agent blocks engagement of any given individual BAFF receptor may affect its clinical utility. [ABSTRACT FROM AUTHOR]

Mammalian genomes contain thousands of genes for long noncoding RNA (lncRNAs), some of which have been shown to affect protein coding gene expression through diverse mechanisms. The lncRNA transcripts are longer than 200 nucleotides and are often capped, spliced, and polyadenylated, but not translated into protein. Nuclear lncRNAs can modify chromatin structure and transcription in trans or cis by interacting with the DNA, forming R-loops, and recruiting regulatory proteins. Not much is known about the role of lncRNA in pituitary gland differentiation and function. We mined transcriptome data from mouse pituitary glands collected at embryonic days 12.5 and 14.5 and identified over 200 different lncRNA transcripts. To develop a research resource for the study of lncRNA, we used pituitary cre transgenes to tag pituitary cell types in adult mice with fluorescent markers, and enriched for thyrotropes, gonadotropes, and somatotropes using fluorescence-activated cell sorting. We determined the transcriptome of each cell population using RNA sequencing and mined the data for lncRNA. We detected hundreds of lncRNAs in adult pituitary cells; a few were located immediately nearby genes that encode pituitary hormones or lineage-specific transcription factors. The location of these lncRNAs suggests the possibility of a cis -acting regulatory role in pituitary development or function, and we observe coordinated expression of 2 of them with their putative target genes in transgenic mice. This research resource sets the foundation for examining the actions of lncRNAs on their putative target genes and determining whether they have roles during development and in response to physiological demand. [ABSTRACT FROM AUTHOR]

Increasing evidence shows that cardiovascular diseases (CVDs) are associated with an increased risk of cognitive impairment and Alzheimer's diseases (AD). It is unknown whether systemic vascular dysfunction occurs prior to the development of AD, if this occurs in a sex-dependent manner, and whether endothelial cells play a role in the deposition of amyloid beta (Aβ) peptides. We hypothesized that vascular dysfunction occurs prior to the onset of amyloid pathology, thus escalating its progression. Furthermore, endothelial cells from female mice will present with an exacerbated formation of Aβ peptides due to an exacerbated pressure pulsatility. To test this hypothesis, we used a double transgenic mouse model of early-onset AD (APPswe/PSEN1dE9). We evaluated hippocampus-dependent recognition memory and the cardiovascular function by echocardiography and direct measurements of blood pressure through carotid artery catheterization. Vascular function was evaluated in resistance arteries, morphometric parameters in the aortas, and immunofluorescence in the hippocampus and aortas. We observed that endothelial dysfunction occurred prior to the onset of amyloid pathology irrespective of sex. However, during the onset of amyloid pathology, only female APP/PS1 mice had vascular stiffness in the aorta. There was elevated Aβ deposition which colocalized with endothelial cells in the hippocampus from female APP/PS1 mice. Overall, these data showed that vascular abnormalities may be an early marker, and potential mediator of AD, but exacerbated aortic stiffness and pressure pulsatility after the onset of amyloid pathology may be associated with a greater burden of Aβ formation in hippocampal endothelial cells from female but not male APP/PS1 mice. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is marked by the presence of intraneuronal neurofibrillary tangles (NFTs), which are primarily composed of hyperphosphorylated tau protein. The locus coeruleus (LC), the brain's main source of norepinephrine (NE), is one of the earliest regions to develop NFTs and experience neurodegeneration in AD. While LC‐derived NE plays beneficial roles in cognition, emotion, locomotion, and the sleep–wake cycle, its impact on tau pathology is unclear. To explore this relationship, we administered intraperitoneal injections of either N‐(2‐chloroethyl)‐N‐ethyl‐2‐bromobenzylamine (DSP4), a selective neurotoxin for noradrenergic neurons, or reboxetine (RBX), a norepinephrine reuptake inhibitor, to decrease or increase NE levels, respectively, in early tau transgenic mice expressing mutant human P301L tau (ADLPTau) for two months. Only the RBX‐treated mice exhibited cognitive deficits, as evidenced by their performance in the Y‐maze, novel object recognition, and contextual fear conditioning tests. Immunohistochemical analysis revealed increased hyperphosphorylated tau aggregates in the LC and hippocampus of the RBX‐treated mice. Furthermore, neuronal apoptosis was observed in the hippocampal CA1 region of these mice. Western blotting showed that RBX injections led to the overactivation of tau kinases PKA and GSK3β, resulting in hyperphosphorylated tau, neuronal loss, and cognitive impairments. Consistent with these findings, human brain organoids exposed to higher NE concentrations also displayed elevated hyperphosphorylated tau and increased activity of the same tau kinases. These findings suggest that excessive NE exposure accelerates tau pathology by overactivating the tau kinases. Thus, modulating NE levels in the brain via the LC‐NE system could be a potential therapeutic strategy for tau‐related AD. [ABSTRACT FROM AUTHOR]

Induced neural stem cells (iNSCs), which have similar properties to neural stem cells and are able to self-proliferate and differentiate into neural cell lineages, are expected to be potential cells for the treatment of neurodegeneration disease. However, cell therapy based on iNSCs transplantation is limited by the inability to acquire sufficient quantities of iNSCs. Previous studies have found that mouse and human fibroblasts can be directly reprogrammed into iNSCs with a single factor, Sox2. Here, we induced mouse embryonic fibroblasts (MEFs) into iNSCs by combining valproic acid (VPA) with the induction factor Sox2, and the results showed that VPA significantly improved the conversion efficiency of fibroblasts to iNSCs. The iNSCs exhibited typical neurosphere-like structures that can express NSCs markers, such as Sox2, Nestin, Sox1, and Zbtb16, and could differentiate into neurons, astrocytes, and oligodendrocytes in vitro. Subsequently, the iNSCs were stereotactically transplanted into the hippocampus of APP/PS1 double transgenic mice (AD mice). Post-transplantation, the iNSCs showed long-term survival, migrated over long distances, and differentiated into multiple types of functional neurons and glial cells in vivo. Importantly, the cognitive abilities of APP/PS1 mice transplanted with iNSCs exhibited significant functional recovery. These findings suggest that VPA enhances the conversion efficiency of fibroblasts into iNSCs when used in combination with Sox2, and iNSCs hold promise as a potential donor material for transplantation therapy in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Background: Osteoarthritis (OA) is a common degenerative joint disease, leading to pain and restricted mobility. Age-related endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of OA, but the underlying mechanisms remain unclear. This study aims to explore the relationship between age-related ER stress, YAP overexpression, and chondrocyte phenotype loss in the development of OA. Methods: Cartilage samples were collected from patients undergoing amputation, and age-related ER stress markers and YAP expression were assessed using immunohistochemical staining and qPCR. Transgenic mice with cartilage-specific YAP overexpression (YAPOE) were created, and Pamrevlumab was administered to evaluate its therapeutic effects. Results: Higher expression of ER stress markers and YAP were showed in aged tissues compared to younger tissues. YAP overexpression led to decreased levels of cartilage phenotype markers and increased osteogenesis-related proteins. In vivo , YAPOE mice exhibited OA-like cartilage degeneration, which was mitigated by Pamrevlumab treatment. Conclusion: Age-related ER stress induces YAP overexpression, contributing to OA pathogenesis. Pamrevlumab effectively prevents this phenotype loss in YAPOE mice, suggesting its potential as a therapeutic agent for OA. These findings provide new insights into the molecular mechanisms of OA and highlight the importance of targeting the ER stress-YAP-CTGF signaling pathway in OA treatment and prevention. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD), an age-related neurodegenerative disorder, is characterized by irreversible brain tissue degeneration. The amyloid-β (Aβ) cascade hypothesis stands as the predominant paradigm explaining AD pathogenesis. This study aimed to elucidate the mechanisms underlying Aβ-induced pyroptosis in AD. AD models were established using amyloid precursor protein/presenilin 1 (APP/PS1) transgenic mice and Aβ-treated BV-2 cells (5 µM, 24 h). NEK7 expression was evaluated in vitro and in vivo. Cell pyroptosis was assessed before and after NEK7 expression was inhibited in BV-2 cells. Adeno-associated virus (AAV) vectors carrying short hairpin RNA (shRNA) against NEK7 (AAV-sh-NEK7) were administered to mice to knockdown NEK7 in vivo. Spatial learning and memory abilities were evaluated using the Morris water maze test. The interaction between NEK7 and histone H4 lysine 12 lactylation (H4K12la) were then investigated. The results suggested that NEK7 expression was markedly elevated in both in vitro and in vivo AD models. Treatment with Aβ significantly reduced cell viability and enhanced pyroptosis in BV-2 cells; these effects were reversed by inhibiting NEK7. Furthermore, AD mice with NEK7 knockdown exhibited shorter escape latencies and increased time spent in the target quadrant, suggesting that NEK7 inhibition improved cognitive function and memory retention. Mechanistically, Aβ treatment induced histone lactylation in BV-2 cells, and suppression of lactylation attenuated NEK7 transcriptional activity and mRNA levels. In summary, elevated NEK7 expression promoted histone lactylation in BV-2 cells, thereby facilitating pyroptosis. Inhibition of NEK7 conferred protection against Aβ-induced cellular damage and enhanced cognitive performance and memory retention in AD model mice. Collectively, targeting NEK7 represents a potential therapeutic strategy for alleviating AD symptoms. [ABSTRACT FROM AUTHOR]

The document published in Acta Neuropathologica discusses the unsuccessful transmissions of atypical genetic Creutzfeldt–Jakob disease (PRNP p.T183A-129M) in transgenic mice. This specific genetic mutation is associated with early onset of the disease and a unique immunoblot profile. The study aimed to evaluate the transmission properties of this genetic prion disease in various animal recipients but found no evidence of transmission in any inoculated mice, highlighting the distinct features of this particular genetic form of the disease. The study suggests that abnormal glycosylation may play a role in the reduced transmission efficiency associated with this genetic variant. [Extracted from the article]

Introduction: Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic condition characterized by premature aging, impacting multiple organ systems, including cardiovascular, musculoskeletal, and integumentary. Significant abnormalities in a transgenic mouse model (homozygous G608G mutation), specifically targeting the development of skull and facial bone indices through high-resolution CT scanning and cephalometric analysis. Methods: Key measurements include bone thickness, skull volume, and cranial suture integrity. Bone volume increased significantly in HGPS mice by 8 months of age compared to wildtype mice. Results: Cortical thickness showed a trend toward increased values in HGPS mice. Cranial metrics revealed distinct differences. Discussion: HGPS mice exhibited smaller internasal width, interzygomatic distance, and palatine length compared to WT mice over time. [ABSTRACT FROM AUTHOR]

Background: Activating the ubiquitin-proteasome system to dismantle disease- related proteins such as tau, β-amyloid, APP, and α-synuclein is an important focus in the research of neurodegenerative proteinopathy. By analyzing the serum RNA extracted from wild-type and Alzheimer's disease (AD) transgenic mice at different ages (4, 8, and 12 months), this study revealed a new protective role of FBXL16 in AD, primarily through facilitating the degradation of disease-related proteins via the ubiquitin proteasome system. Methods: Proteomic analysis were conducted using protein lysates from HEK293 cells overexpressing FBXL16 to identify potential interacting proteins that interact with FBXL16. Subsequent experiments demonstrated that FBXL16 promotes the proteasomal degradation of the APP protein, as evidenced by co-immunoprecipitation with MG132 and cycloheximide (CHX), immunohistochemistry (IHC) and immunocytochemistry (ICC). Memory and cognitive improvements were observed in 3×Tg AD mice through the use of a lentivirus-mediated approach to generate a brain-specific AD mouse model overexpressing FBXL16 via stereotaxic injection. Furthermore, a brain-specific conditional knockout (cko) FBXL16 mouse model was generated and employed to further confirm the functional role of FBXL 16 in AD via various behavioral tests including Morris water maze and Y-maze. Results: The level of FBXL16 in the brains of transgenic APP/PSEN mice with AD decreased with age. Accelerated degradation of APP was observed when FBXL16 was overexpressed in the hippocampi of these AD mice via a lentivirus. This process led to notable improvements in cognitive impairments and reductions in neuroinflammation. Further studies using proteomics and bioinformatics techniques identified transcription factors and binding proteins associated with FBXL16, providing deeper insights into the potential role of FBXL16 in the regulation of AD. Finally, the in vivo effects of FBXL16 deficiency were further substantiated in cko mice, which overexpress Aβ but specifically lack FBXL16 in the brain region. Conclusions: These findings suggest that FBXL16 could be a new regulator of AD. These findings provide a foundation for further research into drug development and potential therapeutic strategies to combat other related neurodegenerative proteinopathies. [ABSTRACT FROM AUTHOR]

Sodium oligomannate (GV-971), an oligosaccharide drug approved in China for treating mild-to-moderate Alzheimer's disease (AD), was previously found to recondition the gut microbiota and limit altered peripheral Th1 immunity in AD transgenic mice. As a follow-up study, we here made advances by pinpointing a Lactobacillus murinus (L.m.) strain that highly expressed a gene encoding a putative adhesin containing Rib repeats (Ribhigh-L.m.) particularly enriched in 5XFAD transgenic mice. Mechanistically, Ribhigh-L.m. adherence to the gut epithelia upregulated fecal metabolites, among which lactate ranked as the top candidate. Excess lactate stimulated the epithelial production of serum amyloid A (SAA) in the gut via the GPR81-NFκB axis, contributing to peripheral Th1 activation. Moreover, GV-971 disrupted the adherence of Ribhigh-L.m. to gut epithelia via direct binding to Rib, which corrected the excess lactate, reduced SAA, and alleviated Th1-skewed inflammation. Together, we gained further insights into the molecular link between gut bacteria and AD progression and the mechanism of GV-971 in treating AD. [ABSTRACT FROM AUTHOR]

Background: Human adenovirus type 7 (HAdV7) has become a major public health threat due to its widespread transmission, severe associated pneumonia, and a lack of effective anti-HAdV7 drugs. The aim of the current study is to design a humanized monoclonal antibody (mAb) demonstrating efficacy against HAdV-7 infections in vitro and in vivo. Methods: The humanized neutralizing antibody, 3G5-hu, was derived from the murine mAb 3G5. Antibody activity was evaluated using a flow cytometry-based neutralization (FCN) assay to identify humanized mAbs retaining potent neutralizing activity. Additionally, a humanized hDSG2/hCD46 dual-receptor transgenic mouse model was developed to simulate HAdV-7 infection. Results: Using recombinant HAdV-7 expressing enhanced green fluorescent protein and clinically isolated wild-type HAdV-7, the half-maximal effective concentration of 3G5-hu against HAdV-7 was determined to be < 30 ng/mL. Notably, 3G5-hu exhibits high specificity for the hexon protein of the HAdV-7 capsid (affinity: KD = 9.02 × 10− 11 M). Microneutralization studies with wild-type HAdV-7 and rAd7EGFP confirmed that humanized mAb 3G5-hu neutralizes 10–30 ng/mL HAdV-7 (approximately 67–200 pM). Furthermore, hDSG2/hCD46 double-receptor transgenic mice are more susceptible to HAdV-7 infection than single-receptor transgenic mice. Meanwhile, the humanized mAb 3G5-hu provides good protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. Conclusions: The newly designed humanized mAb 3G5-hu specifically neutralizes HAdV-7 in vitro and in vivo. 3G5-hu elicits protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. The findings of this study provide insights to guide the future development of preventative and therapeutic treatments for HAdV-7 infection. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a debilitating and fatal paralytic disorder associated with motor neuron death. Mutant superoxide dismutase 1 (SOD1) misfolding and aggregation have been linked to familial ALS, with the accumulation of abnormal wild-type SOD1 species being also observed in postmortem tissue of sporadic ALS cases. Both wild-type and mutated SOD1 are reported to contribute to motoneuron cell death. The autophagic pathway has been shown to be dysregulated in ALS. Recent evidence suggests a dual time-dependent role of autophagy in the progression of the disease. PACER, also called RUBCNL (Rubicon-like), is an enhancer of autophagy and has been found diminished in its levels during ALS pathology in mice and humans. Pacer loss of function disturbs the autophagy process and leads to the accumulation of SOD1 aggregates, as well as sensitizes neurons to death. Therefore, here we investigated if constitutive overexpression of PACER in neurons since early development is beneficial in an in vivo model of ALS. We generated a transgenic mouse model overexpressing human PACER in neurons, which then was crossbred with the mutant SOD1G93A ALS mouse model. Unexpectedly, PACER/SOD1G93A double transgenic mice exhibited an earlier disease onset and shorter lifespan than did littermate SOD1G93A mice. The overexpression of PACER in neurons in vivo and in vitro increased the accumulation of SOD1 aggregates, possibly due to impaired autophagy. These results suggest that similar to Pacer loss-of function, Pacer gain-of function is detrimental to autophagy, increases SOD1 aggregation and worsens ALS pathogenesis. In a wider context, our results indicate the requirement to maintain a fine balance of PACER protein levels to sustain proteostasis. [ABSTRACT FROM AUTHOR]

In this study, the distinct patterns of glial response and neurodegeneration within the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus were examined in 5XFAD mice at 6 and 12 months of age. The primary feature of this transgenic mouse model is the rapid onset of amyloid pathology. We employed quantitative assessments via immunohistochemistry, incorporating double staining techniques, followed by observation with light microscopy and subsequent digital analysis of microscopic images. We identified significantly increased Aβ deposition in these three hippocampal regions at 6 and 12 months of transgenic mice. Moreover, the CA1 and CA3 regions showed higher vulnerability, with signs of reactive astrogliosis such as increased astrocyte density and elevated GFAP expression. Additionally, we observed a significant rise in microglia density, along with elevated inflammatory markers (TNFα) in these hippocampal regions. These findings highlight a non-uniform glial and neuronal response to Aβ plaque deposition within the hippocampal regions of 5xFAD mice, potentially contributing to the neurodegenerative and memory deficit characteristics of Alzheimer's disease in this model. [ABSTRACT FROM AUTHOR]

Alexander disease (AxD) is an intractable neurodegenerative disease caused by mutations in glial fibrillary acidic protein (GFAP), which is predominantly expressed in astrocytes. Thus, AxD is a primary astrocyte disease. However, it remains unclear how GFAP mutations affect astrocytes and cause AxD pathology. Three features are characteristic of AxD astrocytes in vivo: (1) Rosenthal fibers (RFs), the hallmark of AxD; (2) aberrant Ca2+ signals (AxCa); and (3) upregulation of disease-associated genes (AxGen). We established a primary culture system for astrocytes from an AxD transgenic mouse model, and used it to analyze the above features of AxD pathogenesis in astrocytes in vitro. We observed the formation of RFs in AxD primary cultures. The abundance of RFs was greater in AxD-transgene-homozygous compared with -hemizygous astrocytes, indicating a gene dosage effect, and this abundance increased with time in culture, indicating a developmental process effect. However, cultured AxD astrocytes did not exhibit changes in either AxCa or AxGen. We therefore conclude that RFs in astrocytes form via a cell-autonomous mechanism, whereas AxCa and AxGen are likely to occur via a non-cell-autonomous mechanism through interactions with other cells, such as neurons, microglia, and vascular cells. Although primary cultured AxD astrocytes are suitable for elucidating the mechanisms of RFs formation and for intervention studies, it should be noted that they cannot reflect the pathophysiology of non-cell-autonomous events in astrocytes. [ABSTRACT FROM AUTHOR]

Endocannabinoids have attracted great interest for their ability to counteract the neuroinflammation underlying Alzheimer's disease (AD). Our study aimed at evaluating whether this activity was also due to a rebalance of autophagic mechanisms in cellular and animal models of AD. We supplied URB597, an inhibitor of Fatty-Acid Amide Hydrolase (FAAH), the degradation enzyme of anandamide, to microglial cultures treated with Aβ25-35, and to Tg2576 transgenic mice, thus increasing the endocannabinoid tone. The addition of URB597 did not alter cell viability and induced microglia polarization toward an anti-inflammatory phenotype, as shown by the modulation of pro- and anti-inflammatory cytokines, as well as M1 and M2 markers; moreover microglia, after URB597 treatment released higher levels of Bdnf and Nrf2, confirming the protective role underlying endocannabinoids increase, as shown by RT-PCR and immunofluorescence experiments. We assessed the number and area of amyloid plaques in animals administered with URB597 compared to untreated animals and the expression of autophagy key markers in the hippocampus and prefrontal cortex from both groups of mice, via immunohistochemistry and ELISA. After URB597 supply, we detected a reduction in the number and areas of amyloid plaques, as detected by Congo Red staining and a reshaping of microglia activation as shown by M1 and M2 markers' modulation. URB597 administration restored autophagy in Tg2576 mice via an increase in BECN1 (Beclin1), ATG7 (Autophagy Related 7), LC3 (light chain 3) and SQSTM1/p62 (sequestrome 1) as well as via the activation of the ULK1 (Unc-51 Like Autophagy Activating Kinase 1) signaling pathway, suggesting that it targets mTOR/ULK1-dependent autophagy pathway. The potential of endocannabinoids to rebalance autophagy machinery may be considered as a new perspective for therapeutic intervention in AD. [ABSTRACT FROM AUTHOR]

Astrocytes derive from different lineages and play a critical role in neuropathic pain after spinal cord injury (SCI). Whether selectively eliminating these main origins of astrocytes in lumbar enlargement could attenuate SCI-induced neuropathic pain remains unclear. Through transgenic mice injected with an adeno-associated virus vector and diphtheria toxin, astrocytes in lumbar enlargement were lineage traced, targeted, and selectively eliminated. Pain-related behaviors were measured with an electronic von Frey apparatus and a cold/hot plate after SCI. RNA sequencing, bioinformatics analysis, molecular experiment, and immunohistochemistry were used to explore the potential mechanisms after astrocyte elimination. Lineage tracing revealed that the resident astrocytes but not ependymal cells were the main origins of astrocytes- induced neuropathic pain. SCIinduced mice to obtain significant pain symptoms and astrocyte activation in lumbar enlargement. Selective resident astrocyte elimination in lumbar enlargement could attenuate neuropathic pain and activate microglia. Interestingly, the type I interferons (IFNs) signal was significantly activated after astrocytes elimination, and the most activated Gene Ontology terms and pathways were associated with the type I IFNs signal which was mainly activated in microglia and further verified in vitro and in vivo. Furthermore, different concentrations of interferon and Stimulator of interferon genes (STING) agonist could activate the type I IFNs signal in microglia. These results elucidate that selectively eliminating resident astrocytes attenuated neuropathic pain associated with type I IFNs signal activation in microglia. Targeting type I IFNs signals is proven to be an effective strategy for neuropathic pain treatment after SCI. [ABSTRACT FROM AUTHOR]

Mammalian prions are neurotropic pathogens formed from PrPSc assemblies, a misfolded variant of the host‐encoded prion protein PrPC. Multiple PrPSc conformations or strains self‐propagate in host populations or mouse models of prion diseases, exhibiting distinct biological and biochemical phenotypes. Constrained interactions between PrPSc and PrPC conformations confer species specificity and regulate cross‐species transmission. The pathogenicity of fibrillar assemblies derived from bacterially expressed recombinant PrP (rPrP) has been instrumental in demonstrating the protein‐only nature of prions. Yet, their ability to encode different strains and transmit between species remains poorly studied, hampering their use in exploring structure‐to‐strain relationships. Fibrillar assemblies from rPrP with hamster, mouse, human, and bovine primary structures were generated and tested for transmission and adaptation in tg7 transgenic mice expressing hamster PrPC. All assemblies, except the bovine ones, were fully pathogenic on the primary passage, causing clinical disease, PrPSc brain deposition, and spongiform degeneration. They exhibited divergent adaptation processes and strain properties upon subsequent passage. Assemblies of hamster origin propagated without apparent need for adaptation, those of mouse origin adapted abruptly, and those of human origin required serial passages for optimal fitness. Molecular analyses revealed the presence of endogenously truncated PrPSc species in the resulting synthetic strains that lack the 90–140 amino acid region considered crucial for infectivity. In conclusion, rPrP assemblies provide a facile means of generating novel prion strains with adaptative/evolutive properties mimicking genuine prions. The PrP amino acid backbone is sufficient to encode different strains with specific adaptative properties, offering insights into prion transmission and strain diversity. [ABSTRACT FROM AUTHOR]

Background: Physical exercise has been shown to be beneficial for individuals with Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. Methods: Six-month-old Amyloid precursor protein/Presenilin 1 (APP/PS1) transgenic (Tg) mice and wild-type (Wt) mice were randomly assigned to either a sedentary group (Tg-Sed, Wt-Sed) or an exercise group (Tg-Ex, Wt-Ex) undertaking a 12-week, moderate-intensity treadmill running program. Consequently, all mice were tested for memory function and amyloid β (Aβ) levels and phosphorylation of tau and protein kinase B (Akt)/glycogen synthase kinase-3 (GSK3) were examined in tissues of both the cortex and hippocampus. Results: Tg-Sed mice had severely impaired memory, higher levels of Aβ, and increased phosphorylation of tau, GSK3α tyrosine279, and GSK3β tyrosine216, but less phosphorylation of GSK3α serine21, GSK3β serine9, and Akt serine473 in both tissues than Wt-Sed mice in respective tissues. Tg-Ex mice showed significant improvement in memory function along with lower levels of Aβ and less phosphorylation of tau (both tissues), GSK3α tyrosine279 (both tissues), and GSK3β tyrosine216 (hippocampus only), but increased phosphorylation of GSK3α serine21 (both tissues), GSK3β serine9 (hippocampus only), and Akt serine473 (both tissues) compared with Tg-Sed mice in respective tissues. Conclusions: Moderate-intensity aerobic exercise is highly effective in improving memory function in 9-month-old APP/PS1 mice, most likely through differential modulation of GSK3α/β phosphorylation in the cortex and hippocampus. [ABSTRACT FROM AUTHOR]

The serotonergic system modulates the neural circuits involved in jaw movement; however, the role of serotonin (5-HT) neurons in masticatory movement remains unclear. Here, we investigated the effect of selective activation of 5-HT neurons in the dorsal raphe nucleus (DRN), or the raphe obscurus nucleus (ROb), on voluntary masticatory movement using transgenic mice expressing the channelrhodopsin-2 (ChR2) mutant (C128S) in central 5-HT neurons. During voluntary mastication, DRN blue light illumination increased masticatory frequency and decreased the root mean square peak amplitude of electromyography (EMG) in the masseter muscles. DRN blue light illumination also decreased EMG burst duration in the masseter and digastric muscles. These changes were blocked by a 5-HT2A receptor antagonist. Conversely, ROb blue light illumination during voluntary mastication did not affect masticatory frequency and EMG bursts in the masseter and digastric muscles. DRN or ROb blue light illumination during the resting state did not induce rhythmic jaw movement such as mastication but induced an increase in EMG activity in masseter and digastric muscles. These results suggest that both DRN and ROb 5-HT neurons may facilitate jaw movement. Furthermore, DRN 5-HT neuron may contribute to changes in masticatory patterns during the masticatory sequence. [ABSTRACT FROM AUTHOR]

Middle East respiratory syndrome coronavirus (MERS-CoV) and the pangolin MERS-like coronavirus MjHKU4r-CoV-1 employ dipeptidyl peptidase 4 (DPP4) as an entry receptor. MjHKU4r-CoV-1 could infect transgenic mice expressing human DPP4. To understand the mechanism of MjHKU4r-CoV-1 entry into cells, we determined the crystal structures of the receptor binding domain (RBD) of MjHKU4r-CoV-1 spike protein bound to human DPP4 (hDPP4) and Malayan pangolin DPP4 (MjDPP4), respectively. The overall hDPP4-binding mode of MjHKU4r-CoV-1 RBD is similar to that of MERS-CoV RBD. MjHKU4r-CoV-1 RBD shows higher binding affinity to hDPP4 compared to the bat MERS-like coronavirus Ty-BatCoV-HKU4. Via swapping residues between MjHKU4r-CoV-1 RBD and Ty-BatCoV-HKU4 RBD, we identified critical determinants on MjHKU4r-CoV-1 that are responsible for virus usage of hDPP4. Our study suggests that MjHKU4r-CoV-1 is more adapted to the human receptor compared to the bat HKU4 coronavirus and highlights the potential of virus emergence into the human population. Author summary: MjHKU4r-CoV-1 is a MERS-like coronavirus isolated in Malayan pangolins. As a pangolin coronavirus that evolves from its counterparts in bats, MjHKU4r-CoV-1 could use bat, pangolin or human dipeptidyl peptidase 4 (DPP4) as an entry receptor. MjHKU4r-CoV-1 is infectious in human organs and human DPP4 transgenic mice as well and therefore shows the risk of infecting humans. However, the mechanism of receptor recognition by MjHKU4r-CoV-1 is not clear, which is important for evaluating the zoonotic potential of the virus. Here, we showed that MjHKU4r-CoV-1 entered human DPP4 expressing cells more efficiently than its bat progenitor, Ty-BatCoV-HKU4. We further determined the crystal structures of MjHKU4r-CoV-1 receptor binding domains (RBDs) complexed with human DPP4 and pangolin DPP4, respectively. Based on structure guided mutagenesis studies, we identified key residues on MjHKU4r-CoV-1 that determined the virus preference for human DPP4 receptor. Therefore, our study implies that the pangolin coronavirus MjHKU4r-CoV-1 have a risk of emergence into the human population. Future surveillance studies of pangolins and other animals are necessary to determine the transmission chains and zoonotic potential of MjHKU4r-CoV-1. [ABSTRACT FROM AUTHOR]

Prion diseases are transmissible, fatal neurologic diseases of mammals caused by the accumulation of mis-folded, disease associated prion protein (PrPd). Creutzfeldt-Jakob Disease (CJD) is the most common human prion disease and can occur by sporadic onset (sCJD) (~85% of CJD cases), genetic mutations in the prion protein gene (10–15%) or iatrogenic transmission (rare). PrPd is difficult to inactivate and many methods to reduce prion infectivity are dangerous, caustic, expensive, or impractical. Identifying viable and safe methods for decontamination of CJD exposed materials is critically important for medical facilities and research institutions. Previous research has shown that concentrated sodium hypochlorite (bleach) was effective at inactivation of CJD prions derived from brains of mice or guinea pigs. Unfortunately, human prions adapted to rodents may mis-fold differently than in humans, and the rodent adapted prions may not have the same resistance or susceptibility to inactivation present in bona fide CJD prions. To confirm that bleach was efficacious against human sourced CJD prions, we exposed different subtypes of sCJD-infected human brain homogenates to different concentrations of bleach for increasing exposure times. Initial and residual prion seeding activity following inactivation were measured using Real-Time Quaking Induced Conversion. In addition, we tested how passage of human sCJD into either transgenic mice that expressed human prion protein, or transmission of CJD to human cerebral organoids (CO), two common laboratory practices, may affect CJD prions' susceptibility to bleach inactivation. Our results show that bleach is effective against human sourced sCJD prions, and both treatment time and concentration of bleach were important factors for CJD inactivation. CJD derived from human brains, transgenic mouse brains or CO were all susceptible to inactivation with as low as a 10 percent bleach solution with a 30-minute exposure time or a 50 percent bleach solution with as little as a 1-minute exposure time. [ABSTRACT FROM AUTHOR]

Autophagy disorders in AD patients and animal models were well known, however, the effect of P301S‐tau on autophagy is not clear. Here, we found that autophagy related protein Tectonin Beta‐Propeller Repeat‐Containing Protein 1 (TECPR1) decreased in the hippocampus of P301S‐tau transgenic mice by proteomics, which was proved in vivo and in vitro, and P301S‐tau induced autophagic deficits in early and late process. TECPR1 overexpression attenuated P301S‐tau induced autophagy defects via promoting autophagosome generation and autophagosome and lysosomes fusion. We also found that TECPR1 overexpression ameliorated the behavior disorders of P301S‐tau mice with promoting tau degradation, improving synaptic plasticity and neuron loss. Lastly, CQ or 3‐MA treatment reversed TECPR1 induced improvement effects on autophagic and cognitive disorders, further proved that, TECPR1 activated the early and late process of autophagy to ameliorate the cognition of P301S‐tau mice. Our data suggest that TECPR1 is a potential therapy target for AD. [ABSTRACT FROM AUTHOR]

Tau interacts with α-Synuclein (α-Syn) and co-localizes with it in the Lewy bodies, influencing α-Syn pathology in Parkinson's disease (PD). However, whether these biochemical events regulate α-Syn pathology spreading from the gut into the brain remains incompletely understood. Here, we show that α-Syn and Tau co-pathology is spread into the brain in gut-inducible SYN103+/− and/or TAU368+/− transgenic mouse models, eliciting behavioral defects. Gut pathology was initially observed, and α-Syn or Tau pathology was subsequently propagated into the DMV or NTS and then to other brain regions. Remarkably, more extensive spreading and widespread neuronal loss were found in double transgenic mice (Both) than in single transgenic mice. Truncal vagotomy and α-Syn deficiency significantly inhibited synucleinopathy or tauopathy spreading. The α-Syn PET tracer [18F]-F0502B detected α-Syn aggregates in the gut and brain. Thus, α-Syn and Tau co-pathology can propagate from the gut to the brain, triggering behavioral disorders. [Display omitted] • A gut-induced α-Syn and Tau co-pathology mouse model can spread into the brain • Gut-derived pathology is propagated into the DMV and NTS at early stage • Anxiety, cognitive, and motor behavioral impairments appear in a temporal manner • The α-Syn PET tracer [18F]-F0502B can detect α-Syn aggregates in the gut and brain Xiang et al. establish a gut-inducible transgenic mouse model and detect that the gut-derived α-Syn or Tau pathology can propagate into the DMV or NTS and then to other brain regions. The α-Syn PET tracer [18F]-F0502B can detect α-Syn aggregates in the gut and brain. [ABSTRACT FROM AUTHOR]

Background: Recent research suggests a possible role of Notch signaling pathway in development of liver fibrosis, but exact cellular and molecular mechanisms are still not well defined. Methods: We modulated Notch signaling in activated hepatic stellate cells/myofibroblasts using the model of inducible activation or inhibition of Notch signaling selective for αSMA positive cells in murine models of toxic fibrosis induced by CCl4 and cholestatic fibrosis induced by DDC supplemented feeding. Results: Our results confirm that Notch signaling pathway is activated in both CCL4 and DDC model of liver fibrosis and that αSMA positive myofibroblasts are of activated hepatic stellate cells origin. However, neither the inhibition of canonical Notch signaling (in tamoxifen treated αSMACreER/RBP-Jfl/fl mice) nor its overactivation (in tamoxifen treated αSMACreER/NICD1 mice) changed the degree of liver fibrosis in comparison to the control groups in either of the investigated models. Furthermore, after the withdrawal of the fibrogenic treatment the degree of resolution of fibrosis was similar between the animals with Notch overactivation and controls. In addition to genetic manipulation, we investigated the effect of antibodies against NOTCH1 and NOTCH2 on the development of liver fibrosis. Treatment with antibodies had effects on thymus and spleen respectively, but failed to ameliorate liver fibrosis. In conclusion, our data demonstrate that modulation of Notch activity in activated HSC is not sufficient to change the outcome of liver fibrosis. The results obtained with inhibitory antibodies further demonstrate limitations of targeting Notch 1 and 2 receptors as antifibrotic therapy. Notch pathway remains a potential target for the treatment of liver fibrosis, but future studies should be directed to Notch 3 signaling and/or targeting different populations of cells. [ABSTRACT FROM AUTHOR]

Pupil dynamics has emerged as a critical non-invasive indicator of brain state changes. In particular, pupillary-light-responses (PLR) in Alzheimer's disease (AD) patients show potential as biomarkers for brain degeneration. To investigate AD-specific PLR and its underlying neuromodulatory sources, we combine high-resolution awake mouse fMRI with real-time pupillometry to map brain-wide event-related correlation patterns based on illumination-driven pupil constriction ( P c ) and post-illumination pupil dilation recovery (amplitude, P d , and time, T). The P c -driven differential analysis reveals altered visual signal processing and reduced thalamocortical activation in AD mice in comparison with wild-type (WT) control mice. In contrast, the post-illumination pupil dilation recovery-based fMRI highlights multiple brain areas associated with AD brain degeneration, including the cingulate cortex, hippocampus, septal area of the basal forebrain, medial raphe nucleus, and pontine reticular nuclei (PRN). Additionally, the brain-wide functional connectivity analysis highlights the most significant changes in PRN of AD mice, which serves as the major subcortical relay nuclei underlying oculomotor function. This work integrates non-invasive pupil-fMRI measurements in preclinical models to identify pupillary biomarkers based on brain-wide functional changes, including neuromodulatory dysfunction coupled with AD brain degeneration. This work applies high-resolution fMRI with real-time pupillometry in 5xFAD transgenic mice to verify pupillary biomarkers of Alzheimer's disease (AD). In particular, the pupil-driven fMRI maps identify dysfunction of neuromodulatory pathways affected by AD degeneration. [ABSTRACT FROM AUTHOR]

Background:. CD8+ Cytotoxic T lymphocytes play a key role in the pathogenesis of autoimmune diseases and clinical conditions such as graft versus host disease and graft rejection. Mesenchymal Stromal Cells (MSCs) are multipotent cells with tissue repair and immunomodulatory capabilities. Since they are able to suppress multiple pathogenic immune responses, MSCs have been proposed as a cellular therapy for the treatment of immune-mediated diseases. However, the mechanisms underlying their immunosuppressive properties are not yet fully understood. MSCs have the remarkable ability to sense tissue injury and inflammation and respond by donating their own mitochondria to neighboring cells. Whether mitochondrial transfer has any role in the repression of CD8+ responses is unknown. Methods and results:. We have utilized CD8+ T cells from Clone 4 TCR transgenic mice that differentiate into effector cells upon activation in vitro and in vivo to address this question. Allogeneic bone marrow derived MSCs, co-cultured with activated Clone 4 CD8+ T cells, decreased their expansion, the production of the effector cytokine IFNγ and their diabetogenic potential in vivo. Notably, we found that during this interaction leading to suppression, MSCs transferred mitochondria to CD8+ T cells as evidenced by FACS and confocal microscopy. Transfer of MSC mitochondria to Clone 4 CD8+ T cells also resulted in decreased expansion and production of IFNγ upon activation. These effects overlapped and were additive with those of prostaglandin E2 secreted by MSCs. Furthermore, preventing mitochondrial transfer in co-cultures diminished the ability of MSCs to inhibit IFNγ production. Finally, we demonstrated that both MSCs and MSC mitochondria downregulated T-bet and Eomes expression, key transcription factors for CTL differentiation, on activated CD8+ T cells. Conclusion:. In this report we showed that MSCs are able to interact with CD8+ T cells and transfer them their mitochondria. Mitochondrial transfer contributed to the global suppressive effect of MSCs on CD8+ T cell activation by downregulating T-bet and Eomes expression resulting in impaired IFNγ production of activated CD8+ T cells. [ABSTRACT FROM AUTHOR]

Background: Lysosomal homeostasis and functions are essential for the survival of neural cells. Impaired lysosomal biogenesis and acidification in Alzheimer's disease (AD) pathogenesis leads to proteolytic dysfunction and neurodegeneration. However, the key regulatory factors and mechanisms of lysosomal homeostasis in AD remain poorly understood. Methods: ROCK1 expression and its co-localization with LAMP1 and SQSTM1/p62 were detected in post-mortem brains of healthy controls and AD patients. Lysosome-related fluorescence probe staining, transmission electron microscopy and immunoblotting were performed to evaluate the role of ROCK1 in lysosomal biogenesis and acidification in various neural cell types. The interaction between ROCK1 and TFEB was confirmed by surface plasmon resonance and in situ proximity ligation assay (PLA). Moreover, we performed AAV-mediated ROCK1 downregulation followed by immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and behavioral tests to unveil the effects of the ROCK1–TFEB axis on lysosomes in APP/PS1 transgenic mice. Results: ROCK1 level was significantly increased in the brains of AD individuals, and was positively correlated with lysosomal markers and Aβ. Lysosomal proteolysis was largely impaired by the high abundance of ROCK1, while ROCK1 knockdown mitigated the lysosomal dysfunction in neurons and microglia. Moreover, we verified ROCK1 as a previously unknown upstream kinase of TFEB independent of m-TOR or GSK-3β. ROCK1 elevation resulted in abundant extracellular Aβ deposition which in turn bound to Aβ receptors and activated RhoA/ROCK1, thus forming a vicious circle of AD pathogenesis. Genetically downregulating ROCK1 lowered its interference with TFEB, promoted TFEB nuclear distribution, lysosomal biogenesis and lysosome-mediated Aβ clearance, and eventually prevented pathological traits and cognitive deficits in APP/PS1 mice. Conclusion: In summary, our results provide a mechanistic insight into the critical role of ROCK1 in lysosomal regulation and Aβ clearance in AD by acting as a novel upstream serine kinase of TFEB. [ABSTRACT FROM AUTHOR]

Background: Prevention and treatment of metastatic breast cancer (BC) is an unmet clinical need. The retinoic acid derivative fenretinide (FeR) was previously evaluated in Phase I-III clinical trials but, despite its excellent tolerability and antitumor activity in preclinical models, showed limited therapeutic efficacy due to poor bioavailability. We recently generated a new micellar formulation of FeR, Bionanofenretinide (Bio-nFeR) showing enhanced bioavailability, low toxicity, and strong antitumor efficacy on human lung cancer, colorectal cancer, and melanoma xenografts. In the present study, we tested the effect of Bio-nFeR on a preclinical model of metastatic BC. Methods: We used BC cell lines for in vitro analyses of cell viability, cell cycle and migratory capacity. For in vivo studies, we used HER2/neu transgenic mice (neuT) as a model of spontaneously metastatic BC. Mice were treated orally with Bio-nFeR and at sacrifice primary and metastatic breast tumors were analyzed by histology and immunohistochemistry. Molecular pathways activated in primary tumors were analyzed by immunoblotting. Stem cell content was assessed by flow cytometry, immunoblotting and functional assays such as colony formation ex vivo and second transplantation assay in immunocompromised mice. Results: Bio-nFeR inhibited the proliferation and migration of neuT BC cells in vitro and showed significant efficacy against BC onset in neuT mice. Importantly, Bio-nFeR showed the highest effectiveness against metastatic progression, counteracting both metastasis initiation and expansion. The main mechanism of Bio-nFeR action consists of promoting tumor dormancy through a combined induction of antiproliferative signals and inhibition of the mTOR pathway. Conclusion: The high effectiveness of Bio-nFeR in the neuT model of mammary carcinogenesis, coupled with its low toxicity, indicates this formulation as a potential candidate for the treatment of metastatic BC and for the adjuvant therapy of BC patients at high risk of developing metastasis. [ABSTRACT FROM AUTHOR]

Acetylcholinesterase (AChE) has functions in neuroinflammation, beyond its classical role in neurotransmission. Understanding the role of AChE in neuroinflammation is of great significance, as it highlights the potential therapeutic targets for the treatment of neurodegenerative diseases. In an in vitro study, the expression of AChE was up‐regulated in lipopolysaccharide (LPS)‐induced microglia/macrophage and contrarily potentiated the inflammatory responses via disturbing the cholinergic anti‐inflammatory pathway (CAP). However, the regulation of AChE in neuroinflammation has not been revealed in vivo yet. Here, we aim to uncover the inflammatory roles of microglial AChE in LPS‐induced neuroinflammation by using the conditional AChE over‐expression mouse model. AChE was specifically over‐expressed in the myeloid cell linkage of mouse by applying CRISPR/cas9 combined with Cre‐LoxP system. LPS was intraperitoneally injected into the mice to induce inflammation. The results showed that the inflammation, induced by LPS, was aggravated in the brain of transgenic mice having over‐expression of AChE in microglia. The expressions of pro‐inflammatory cytokines were robustly up‐regulated in the brains of LPS‐treated transgenic mice, as compared to the LPS‐treated wildtypes. In parallel, the activations of microglia and astrocytes in hippocampus were enhanced significantly in AChE transgenic mice. Transcriptomics analysis further confirmed the severer inflammation in the transgenic mice than the wildtype after LPS administration. These findings shed light on the regulation of microglial AChE in neuroinflammation in vivo for the first time, presenting another angle to understand the role of AChE in neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Disruption of inhibitory interneurons is common in the epileptic brain and is hypothesized to play a pivotal role in epileptogenesis. Abrupt disruption and loss of interneurons is well-characterized in status epilepticus models of epilepsy, however, status epilepticus is a relatively rare cause of epilepsy in humans. How interneuron disruption evolves in other forms of epilepsy is less clear. Here, we explored how somatostatin (SST) interneuron disruption evolves in quadruple transgenic Gli1-CreERT2, Ptenfl/fl, SST-FlpO, and frt-eGFP mice. In these animals, epilepsy develops following deletion of the mammalian target of rapamycin (mTOR) negative regulator phosphatase and tensin homolog (Pten) from a subset of dentate granule cells, while downstream Pten-expressing SST neurons are fate-mapped with green fluorescent protein (GFP). The model captures the genetic complexity of human mTORopathies, in which mutations can be restricted to excitatory neuron lineages, implying that interneuron involvement is later developing and secondary. In dentate granule cell (DGC)-Pten knockouts (KOs), the density of fate-mapped SST neurons was reduced in the hippocampus, but their molecular phenotype was unchanged, with similar percentages of GFP+ cells immunoreactive for SST and parvalbumin (PV). Surviving SST neurons in the dentate gyrus had larger somas, and the density of GFP+ processes in the dentate molecular layer was unchanged despite SST cell loss and expansion of the molecular layer, implying compensatory sprouting of surviving cells. The density of Znt3-immunolabeled puncta, a marker of granule cell presynaptic terminals, apposed to GFP+ processes in the hilus was increased, suggesting enhanced granule cell input to SST neurons. Finally, the percentage of GFP+ cells that were FosB positive was significantly increased, implying that surviving SST neurons are more active. Together, findings suggest that somatostatin-expressing interneurons exhibit a combination of pathological (cell loss) and adaptive (growth) responses to hyperexcitability and seizures driven by upstream Pten KO excitatory granule cells. Illustration and summary of key study findings. The left portion of the illustration depicts DGC and SST interneuron interaction in normal conditions. The right portion depicts changes in the setting of DGC-Pten KO which are supported by the following findings in this study: (1) eGFP-SST cell density was reduced in multiple hippocampal regions. Remaining hilar eGFP-SST cells exhibited larger soma sizes. (2) Preserved eGFP-SST processes in the hilus and molecular layer, coupled with cell loss and an enlarged molecular layer, suggests sprouting. (3) Increased apposition of Znt-3 puncta to eGFP-SST processes suggests increased DGC innervation of SST interneurons. Created in BioRender.com. BioRender.com/h33m167. [ABSTRACT FROM AUTHOR]

Since the mid-1990s, scientists have been generating mouse models of Alzheimer's disease to elucidate key mechanisms underlying the onset and progression of the disease and aid in developing potential therapeutic approaches. The first successful mouse model of Alzheimer's disease was reported in 1995 with the generation of the PDAPP mice, which were obtained by the overexpression of gene coding for the amyloid precursor protein (APP). Since then, scientists have used different approaches to develop other APP overexpression mice, mice overexpressing tau, or a combination of them. More recently, Saito and colleagues generated a mouse model by knocking in mutations associated with familial Alzheimer's disease into the APP gene. In this review, we will describe the most used animal models and provide a practical guide for the disease's age of onset and progression. We believe that this guide will be valuable for the planning and experimental design of studies utilizing these mouse models. [ABSTRACT FROM AUTHOR]

Atrial fibrillation (AF) is a common cardiovascular disease often observed in diabetes mellitus, and there is currently no satisfactory therapeutic option. Ubiquitin-specific protease 38 (USP38) has been implicated in the degradation of numerous substrate proteins in the myocardium. Herein, we aim to investigate the role of USP38 in AF induced by diabetes. Cardiac-specific transgenic USP38 mice and cardiac-specific knockout USP38 mice were constructed, and streptozotocin was used to establish diabetic mouse model. Functional, electrophysiological, histologic, biochemical studies were performed. The expression of USP38 was upregulated in atrial tissues of diabetic mice and HL-1 cells exposed to high glucose. USP38 overexpression increased susceptibility to AF, accompanied by aberrant expression of calcium-handling protein, heightened iron load and oxidation stress in diabetic mice. Conversely, USP38 deficiency reduced vulnerability to AF by hampering ferroptosis. Mechanistically, USP38 bound to iron regulatory protein 2 (IRP2), stabilizing it and remove K48-linked polyubiquitination chains, thereby increasing intracellular iron overload, lipid peroxidation, and ultimately contributing to ferroptosis. In addition, reduced iron overload by deferoxamine treatment alleviated oxidation stress and decreased vulnerability to AF in diabetic mice. Overall, our findings reveal the detrimental role of USP38 in diabetes-related AF, manifested by increased level of iron overload and oxidation stress. [Display omitted] • USP38 was upregulated in the atrial tissues of diabetic mice. • USP38 overexpression increased the induction rate and mean duration of AF in diabetic mice. • Knockout of USP38 reduced susceptibility to AF in diabetic mice. • USP38 stabilized IRP2 to promote iron overload, leading to ferroptosis in diabetic mice. [ABSTRACT FROM AUTHOR]

Flexible MicroLEDs hold great promise as a novel tool for advancing optogenetics, enabling applications in biology. Such applications require the technology to assemble MicroLEDs onto ultra‐thin biocompatible films that conform to the delicate and uneven brain and biological tissues. In this study, a batch transfer technique using thermal release sheets is propsed. By optimizing the gate structures that support the hollow structure, a method to transfer MicroLEDs to the film without causing damage is established. It is successfully demonstrated that the flexible MicroLED films, fabricated using this technique, can be placed on the brain surface of transgenic mice and induce neural activity through optogenetic stimulation. [ABSTRACT FROM AUTHOR]

Lung adenocarcinoma is a common aggressive cancer and a leading cause of mortality worldwide. Here, we report an important in vivo role for mitochondrial DNA (mtDNA) copy number during lung adenocarcinoma progression in the mouse. We found that lung tumors induced by KRASG12D expression have increased mtDNA levels and enhanced mitochondrial respiration. To experimentally assess a possible causative role in tumor progression, we induced lung cancer in transgenic mice with a general increase in mtDNA copy number and found that they developed a larger tumor burden, whereas mtDNA depletion in tumor cells reduced tumor growth. Immune cell populations in the lung and cytokine levels in plasma were not affected by increased mtDNA levels. Analyses of large cancer databases indicate that mtDNA copy number is also important in human lung cancer. Our study thus reports experimental evidence for a tumor-intrinsic causative role for mtDNA in lung cancer progression, which could be exploited for development of future cancer therapies. [ABSTRACT FROM AUTHOR]

Improving energy provision in the failing heart by augmenting the creatine kinase (CK) system is a desirable therapeutic target. However, over-expression of the creatine transporter (CrT-OE) has shown that very high creatine levels result in cardiac hypertrophy and dysfunction. We hypothesise this is due to insufficient endogenous CK activity to maintain thermodynamically favourable metabolite ratios. If correct, then double transgenic mice (dTg) overexpressing both CrT and the muscle isoform of CK (CKM-OE) would rescue the adverse phenotype. In Study 1, overexpressing lines were crossed and cardiac function assessed by invasive haemodynamics and echocardiography. This demonstrated that CKM-OE was safe, but too few hearts had creatine in the toxic range. In Study 2, a novel CrT-OE line was generated with higher, homogeneous, creatine levels and phenotyped as before. Myocardial creatine was 4-fold higher in CrT-OE and dTg hearts compared to wildtype and was associated with hypertrophy and contractile dysfunction. The inability of dTg hearts to rescue this phenotype was attributed to downregulation of CK activity, as occurs in the failing heart. Nevertheless, combining both studies in a linear regression analysis suggests a modest positive effect of CKM over a range of creatine concentrations. In conclusion, we confirm that moderate elevation of creatine is well tolerated, but very high levels are detrimental. Correlation analysis lends support to the theory that this may be a consequence of limited CK activity. Future studies should focus on preventing CKM downregulation to unlock the potential synergy of augmenting both creatine and CK in the heart. [Display omitted] • Improving cardiac energetics via the creatine kinase system can be cardioprotective. • Too much creatine (>2-fold increase) causes heart failure and is not rescued by CK. • LV dysfunction causes transcriptional and post-translational down-regulation of CK. • Aim for modest increases in creatine while preventing loss of CK activity. [ABSTRACT FROM AUTHOR]

The mitochondrial permeability transition (MPT) pore regulates necrotic cell death following diverse cardiac insults. While the componentry of the pore itself remains controversial, Cyclophilin D (CypD) has been well-established as a positive regulator of pore opening. We have previously identified Complement 1q-binding protein (C1qbp) as a novel CypD-interacting molecule and a negative regulator of MPT-dependent cell death in vitro. However, its effects on the MPT pore and sensitivity to cell death in the heart remain untested. We therefore hypothesized that C1qbp would inhibit MPT in cardiac mitochondria and protect cardiac myocytes against cell death in vivo. To investigate the effects of C1qbp in the myocardium we generated gain- and loss-of-function mice. Transgenic C1qbp overexpression resulted in decreased complex protein expression and reduced mitochondrial respiration and ATP production but MPT was unaffected. In contrast, while C1qbp +/− mice did not exhibit any changes in mitochondrial protein expression, respiration, or ATP, the MPT pore was markedly sensitized to Ca2+ in these animals. Neither overexpression nor depletion of C1qbp significantly affected baseline heart morphology or function at 3 months of age. When subjected to myocardial infarction, C1qbp transgenic mice exhibited similar infarct sizes and cardiac remodeling to non-transgenic mice, consistent with the lack of an effect on MPT. In contrast, cardiac scar formation and dysfunction were significantly increased in the C1qbp +/− mice compared to C1qbp +/+ controls. Our results suggest that C1qbp is required for normal regulation of the MPT pore and mitochondrial function, and influences cardiac remodeling following MI, the latter more likely being independent of C1qbp effects on the MPT pore. [Display omitted] • Examined the ability of C1qbp to regulate the MPT pore and cardiac injury in mice • C1qbp transgenesis reduced mitochondrial function but did not affect MPT or cardiac damage and dysfunction following MI • C1qbp haploinsufficiency did not affect function but sensitized the MPT pore to Ca2+ and exacerbated MI-induced pathology • Endogenous C1qbp acts a brake on the MPT pore and the progression of cardiac remodeling and dysfunction following MI [ABSTRACT FROM AUTHOR]

The accumulation of amyloid‐β (Aβ) and overactivation of microglia contribute to the pathogenesis of Alzheimer's disease (AD), but the interaction between microglial activation and Aβ deposition in AD remains elusive. Here we revealed that Aβ activates microglia and promotes the release of Galectin‐9 (Gal‐9), a member of the β‐galactoside–binding family of lectins. The levels of Gal‐9 in the cerebrospinal fluid and brain tissues of AD patients are higher than those in control subjects. Gal‐9 interacts with Aβ and promotes its aggregation, generating Gal‐9‐Aβ fibrils with enhanced seeding activity and neurotoxicity. The expression of Gal‐9 increases with age in the brains of APP/PS1 transgenic mice. Knockout of Gal‐9 in APP/PS1 mice substantially reduced Aβ sedimentation, neuroinflammation, and cognitive impairment. Moreover, depletion of Gal‐9 inhibited the seeding activity of brain homogenates from APP/PS1 mice. These findings reveal a mechanism by which microglia‐derived Gal‐9 accelerates Aβ aggregation and seeding in AD. Thus, strategies aimed at inhibiting Gal‐9 may hold promise as a disease‐modifying therapy to alleviate AD pathology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Constipation was associated with an increased risk of Alzheimer's disease (AD) in the South Korean cohort (discovery cohort, HR, 2.04; 95% CI, 2.01–2.07) and the Japan cohort (validation cohort, HR, 2.82; 95% CI, 2.61–3.05). • Loperamide-treated AD mouse model showed increased amyloid-beta and microglia in the brain with slow gut transit. • Loperamide-treated AD mouse model had increased transcription of genes related to norepinephrine secretion and immune responses and decreased transcription of defense against bacteria in colonic tissue. Although the association between Alzheimer's disease (AD) and constipation is controversial, its causality and underlying mechanisms remain unknown. To investigate the potential association between slow gut transit and AD using epidemiological data and a murine model. We conducted a bi-national cohort study in South Korea (discovery cohort, N=3,130,193) and Japan (validation cohort, N=4,379,285) during the pre-observation period to determine the previous diagnostic history (2009–2010) and the follow-up period (2011–2021). To evaluate the causality, we induced slow gut transit using loperamide in 5xFAD transgenic mice. Changes in amyloid-beta (Aβ) and other markers were examined using ELISA, qRT-PCR, RNA-seq, and behavioral tests. Constipation was associated with an increased risk of AD in the discovery cohort (hazard ratio, 2.04; 95% confidence interval [CI], 2.01–2.07) and the validation cohort (hazard ratio; 2.82; 95% CI, 2.61–3.05). We found that loperamide induced slower gut transit in 5xFAD mice, increased Aβ and microglia levels in the brain, increased transcription of genes related to norepinephrine secretion and immune responses, and decreased the transcription of defense against bacteria in the colonic tissue. Impaired gut transit may contribute to AD pathogenesis via the gut-brain axis, thus suggesting a cyclical relationship between intestinal barrier disruption and Aβ accumulation in the brain. We propose that gut transit or motility may be a modifiable lifestyle factor in the prevention of AD, and further clinical investigations are warranted. [ABSTRACT FROM AUTHOR]

Taste buds contain 2 types of GABA-producing cells: sour-responsive Type III cells and glial-like Type I cells. The physiological role of GABA, released by Type III cells is not fully understood. Here, we investigated the role of GABA released from Type III cells using transgenic mice lacking the expression of GAD67 in taste bud cells (Gad67-cKO mice). Immunohistochemical experiments confirmed the absence of GAD67 in Type III cells of Gad67-cKO mice. Furthermore, no difference was observed in the expression and localization of cell type markers, ectonucleoside triphosphate diphosphohydrolase 2 (ENTPD2), gustducin, and carbonic anhydrase 4 (CA4) in taste buds between wild-type (WT) and Gad67-cKO mice. Short-term lick tests demonstrated that both WT and Gad67-cKO mice exhibited normal licking behaviors to each of the five basic tastants. Gustatory nerve recordings from the chorda tympani nerve demonstrated that both WT and Gad67-cKO mice similarly responded to five basic tastants when they were applied individually. However, gustatory nerve responses to sweet–sour mixtures were significantly smaller than the sum of responses to each tastant in WT mice but not in Gad67-cKO mice. In summary, elimination of GABA signalling by sour-responsive Type III taste cells eliminates the inhibitory cell–cell interactions seen with application of sour–sweet mixtures. [ABSTRACT FROM AUTHOR]

COVID-19 presents with a plethora of neurological signs and symptoms despite being characterized as a respiratory disease, including seizures, anxiety, depression, amnesia, attention deficits, and alterations in consciousness. The olfactory nerve is widely accepted as the neuroinvasive route by which the etiological agent SARS-CoV-2 enters the brain, but the trigeminal nerve is an often-overlooked additional route. Based on this consensus, we initially conducted a pilot experiment investigating the olfactory nerve route of SARS-CoV-2 neuroinvasion via intranasal inoculation in AC70 human ACE2 transgenic mice. Notably, we found that the trigeminal ganglion is an early and highly efficient site of viral replication, which then rapidly spread widely throughout the brain where neurons were primarily targeted. Despite the extensive viral infection across the brain, obvious evidence of tissue pathology including inflammatory infiltration, glial activation, and apoptotic cell deaths were not consistently observed, albeit inflammatory cytokines were significantly induced. However, the expression levels of different genes related to neuronal function, including the neurotransmitter dopamine pathway as well as synaptic function, and markers of neuronal damage were altered as compared to mock-infected mice. Our findings suggest that the trigeminal nerve may serve as a neuroinvasive route complementary to the olfactory nerve and that the ensuing neuroinvasion presented a unique neuropathological profile. This study provides insights into potential neuropathogenic mechanisms utilized by coronaviruses. [ABSTRACT FROM AUTHOR]

Diabetes is a complex metabolic disease which most commonly has a polygenic origin; however, in rare cases, diabetes may be monogenic. This is indeed the case in both Maturity Onset Diabetes of the Young (MODY) and neonatal diabetes. These disease subtypes are believed to be simpler than Type 1 (T1D) and Type 2 Diabetes (T2D), which allows for more precise modelling. During the three last decades, many studies have focused on rodent models. These investigations provided a wealth of knowledge on both pancreas development and beta cell function. In particular, they allowed the establishment of a hierarchy of the transcription factors and highlighted the role of microenvironmental factors in the control of progenitor cell proliferation and differentiation. Transgenic mice also offered the possibility to decipher the mechanisms that define the functional identity of the pancreatic beta cells. Despite such interest in transgenic mice, recent data have also indicated that important differences exist between mice and human. To overcome these limitations, new human models are necessary. In the present review, we describe these ex vivo models, which are created using stem cells and organoids, and represent an important step toward islet cell therapy and drug discovery. [ABSTRACT FROM AUTHOR]

In vivo imaging of large-scale neuronal activity plays a pivotal role in unraveling the function of the brain's circuitry. Multiphoton microscopy, a powerful tool for deep-tissue imaging, has received sustained interest in advancing its speed, field of view and imaging depth. However, to avoid thermal damage in scattering biological tissue, field of view decreases exponentially as imaging depth increases. We present a suite of innovations to optimize three-photon microscopy for large field-of-view imaging at depths unreachable by two-photon microscopy. These techniques enable us to image neuronal activities of transgenic animals expressing protein calcium sensors in a ~ 3.5-mm diameter field-of-view with single-cell resolution in the deepest cortical layer of mouse brains. We further demonstrate simultaneous large field-of-view two-photon and three-photon imaging, subcortical imaging in the mouse brain, and whole-brain imaging in adult zebrafish. The demonstrated techniques can be integrated into typical multiphoton microscopes to enlarge field of view for system-level neural circuit research. [ABSTRACT FROM AUTHOR]

Chronic systemic inflammation caused by diseases such as ulcerative colitis (UC) and Crohn's disease (CD) increases the risk of developing colorectal cancer (CRC). Recent evidence indicates that patients with UC are more susceptible to prostate cancer (PCa), and individuals with PCa may also be at a higher risk of developing CRC. However, these relationships are not well defined. A better understanding of this phenomenon could improve the identification of high-risk populations. In this study, we characterized these relationships with experiments using preclinical mouse models of dextran sulfate sodium (DSS)-induced colitis (DSS-UC) and DSS/azoxymethane (AOM)-induced CRC (DSS/AOM-CRC) in wild-type and conditional transgenic mice of PCa. We showed that DSS-induced UC was more severe in mice with PCa and resulted in the development of CRC in the absence of AOM. We further showed that PCa-free mice that developed DSS-induced UC also showed histological changes in the normal prostate that resembled proliferative inflammatory atrophy. Finally, we used immunohistochemical immune profiling to show that mice with PCa-induced chronic systemic inflammation accumulated Gr1+ myeloid cells in the normal colon and exposure to DSS further enriched these cells in active colitis regions and colon tumors. Our study provides evidence to support a link between systemic chronic inflammation and cancer. [ABSTRACT FROM AUTHOR]

MR33317 was synthesized as an acetylcholinesterase-inhibitor and an agonist at brain 5-HT4-receptors. MR33317 might be used to treat Morbus Alzheimer. This therapeutic action of MR33317 might be based on MR33317´s dual synergistic activity. We tested the hypothesis that MR33317 also stimulates 5-HT4-receptors in the heart. MR33317 (starting at 10 nM) increased force of contraction and beating rate in isolated atrial preparations from mice with cardiac confined overexpression of the human 5-HT4-serotonin receptor (5-HT4-TG) but was inactive in wild type mouse hearts (WT). Only in the presence of the phosphodiesterase III-inhibitor cilostamide, MR33317 raised force of contraction under isometric conditions in isolated paced (1 Hz) human right atrial preparations (HAP). This increase in force of contraction in human atrium by MR33317 was attenuated by 10 µM tropisetron or GR125487. These data suggest that MR33317 is an agonist at human 5-HT4-serotonin receptors in the human atrium. Clinically, one would predict that MR33317 may lead to atrial fibrillation. [ABSTRACT FROM AUTHOR]

Centrosomes are the major microtubule organizing centers of animal cells. Supernumerary centrosomes are a common feature of human tumors and associated with karyotype abnormalities and aggressive disease, but whether they are cause or consequence of cancer remains controversial. Here, we analyzed the consequences of centrosome amplification by generating transgenic mice in which centrosome numbers can be increased by overexpression of the structural centrosome protein STIL. We show that STIL overexpression induces centrosome amplification and aneuploidy, leading to senescence, apoptosis, and impaired proliferation in mouse embryonic fibroblasts, and microcephaly with increased perinatal lethality and shortened lifespan in mice. Importantly, both overall tumor formation in mice with constitutive, global STIL overexpression and chemical skin carcinogenesis in animals with inducible, skin-specific STIL overexpression were reduced, an effect that was not rescued by concomitant interference with p53 function. These results suggest that supernumerary centrosomes impair proliferation in vitro as well as in vivo, resulting in reduced lifespan and delayed spontaneous as well as carcinogen-induced tumor formation. Author summary: Already at the beginning of the last century, Theodor Boveri suggested that supernumerary centrosomes might be a cause of cancer via the generation of abnormal mitotic spindles and subsequent chromosome missegregation. In the meantime, centrosome amplification has been observed in most tumor types and is viewed as a "hallmark" of cancer cells. However, studies on tumor formation in mice by overexpression of PLK4, the principal kinase regulating centrosome duplication, led to ambiguous results, as some but not all models resulted in increased tumorigenesis. In this study, we generated transgenic mice, which overexpress the structural centrosome protein STIL. Similar to PLK4, overexpression of STIL caused centrosome amplification and aneuploidy in mouse cells. Our analyses revealed that powerful mechanisms lead to the elimination of cells with extra centrosomes and/or aneuploidy by impaired proliferation, senescence and apoptosis, thereby delaying both spontaneous tumor formation and chemical skin carcinogenesis, and explaining the reduced life span of STIL-transgenic mice. [ABSTRACT FROM AUTHOR]