Search

Age is the most important risk factor for metabolic alterations and cardiovascular accidents. Although class III histone deacetylases, alias Sirtuins, have been appealed as “the fountain of youth” their role in longevity control and prevention of aging-associated disease is still under debate. Indeed, several lines of evidence indicate that sirtuin activity is strictly linked to metabolism and dependent on NAD + synthesis both often altered as aging progresses. During aging the cardiovascular system is attacked by a variety of environmental stresses, including those determined by high blood glucose and lipid levels, or by the presence of oxidized lipoproteins which, among others, determine important oxidative stress signals. In such a milieu, heart and vessels develop a functional impairment leading to atherosclerosis, ischemia, heart insufficiency and failure. Sirtuins, which are believed to have a positive impact on cardiovascular physiology and physiopathology, are distributed in different subcellular compartments including the nucleus, the cytoplasm and the mitochondria, where they regulate expression and function of a large variety of target genes and proteins. Remarkably, experimental animal models indicate resveratrol, the first natural compound described to positively regulate the activity of sirtuins, as able to protect the endothelium and the heart exposed to a variety of stress agents. This review will focus on the regulation and function of mammalian sirtuins with special attention paid to their role as cardiovascular “defenders” giving indication of their targets of potential relevance for the development of future therapeutics. This article is part of a Special Issue entitled CV Aging. [ABSTRACT FROM AUTHOR]

The concept of the Myc (c-myc, n-myc, l-myc) oncogene as a canonical, DNA-bound transcription factor has consistently changed over the past few years. Indeed, Myc controls gene expression programs at multiple levels: directly binding chromatin and recruiting transcriptional coregulators; modulating the activity of RNA polymerases (RNAPs); and drawing chromatin topology. Therefore, it is evident that Myc deregulation in cancer is a dramatic event. Glioblastoma multiforme (GBM) is the most lethal, still incurable, brain cancer in adults, and it is characterized in most cases by Myc deregulation. Metabolic rewiring typically occurs in cancer cells, and GBM undergoes profound metabolic changes to supply increased energy demand. In nontransformed cells, Myc tightly controls metabolic pathways to maintain cellular homeostasis. Consistently, in Myc-overexpressing cancer cells, including GBM cells, these highly controlled metabolic routes are affected by enhanced Myc activity and show substantial alterations. On the other hand, deregulated cancer metabolism impacts Myc expression and function, placing Myc at the intersection between metabolic pathway activation and gene expression. In this review paper, we summarize the available information on GBM metabolism with a specific focus on the control of the Myc oncogene that, in turn, rules the activation of metabolic signals, ensuring GBM growth. [ABSTRACT FROM AUTHOR]

Highlights: [•] Diabetic complications progress even after blood glucose control is therapeutically achieved. [•] The epigenetic machinery regulates chromatin structure, synchronizing metabolic information with gene expression. [•] Persisting epigenetic marks keep memory of previous transient hyperglycemic events. [•] Epidrugs may represent a potential novel therapeutic option for diabetic patients. [ABSTRACT FROM AUTHOR]

This study investigates the diabetes-associated alterations present in cardiac mesenchymal cells (CMSC) obtained from normoglycemic (ND-CMSC) and type 2 diabetic patients (D-CMSC), identifying the histone acetylase (HAT) activator pentadecylidenemalonate 1b (SPV106) as a potential pharmacological intervention to restore cellular function. D-CMSC were characterized by a reduced proliferation rate, diminished phosphorylation at histone H3 serine 10 (H3S10P), decreased differentiation potential, and premature cellular senescence. A global histone code profiling of D-CMSC revealed that acetylation on histone H3 lysine 9 (H3K9Ac) and lysine 14 (H3K14Ac) was decreased, whereas the trimethylation of H3K9Ac and lysine 27 significantly increased. These observations were paralleled by a down-regulation of the GCN5-related N-acetyltransferases (GNAT) p300/CBP-associated factor and its isoform 5-α general control of amino acid synthesis (GCN5a), determining a relative decrease in total HAT activity. DNA CpG island hypermethylation was detected at promoters of genes involved in cell growth control and genomic stability. Remarkably, treatment with the GNAT proactivator SPV106 restored normal levels of H3K9Ac and H3K14Ac, reduced DNA CpG hypermethylation, and recovered D-CMSC proliferation and differentiation. These results suggest that epigenetic interventions may reverse alterations in human CMSC obtained from diabetic patients. [ABSTRACT FROM AUTHOR]

Recent statistics indicate that the human population is ageing rapidly. Healthy, but also diseased, elderly people are increasing. This trend is particularly evident in Western countries, where healthier living conditions and better cures are available. To understand the process leading to age-associated alterations is, therefore, of the highest relevance for the development of new treatments for age-associated diseases, such as cancer, diabetes, Alzheimer and cardiovascular accidents. Mechanistically, it is well accepted that the accumulation of intracellular damage determined by reactive oxygen species (ROS) might orchestrate the progressive loss of control over biological homeostasis and the functional impairment typical of aged tissues. Here, we review how epigenetics takes part in the control of stress stimuli and the mechanisms of ageing physiology and physiopathology. Alteration of epigenetic enzyme activity, histone modifications and DNA-methylation is, in fact, typically associated with the ageing process. Specifically, ageing presents peculiar epigenetic markers that, taken altogether, form the still ill-defined "ageing epigenome". The comprehension of mechanisms and pathways leading to epigenetic modifications associated with ageing may help the development of anti-ageing therapies. [ABSTRACT FROM AUTHOR]

Histone deacetylase inhibitors (DIs) are promising drugs for the treatment of several pathologies including ischemic and failing heart where they demonstrated efficacy. However, adverse side effects and cardiotoxicity have also been reported. Remarkably, no information is available about the effect of DIs during tissue regeneration following acute peripheral ischemia. In this study, mice made ischemic by femoral artery excision were injected with the DIs MS275 and MC1568, selective for class I and IIa histone deacetylases (HDACs), respectively. In untreatedmice, soon after damage, class IIa HDAC phosphorylation and nuclear export occurred, paralleled by dystrophin and neuronal nitric-oxide synthase (nNOS) down-regulation and decreased protein phosphatase 2A activity. Between 14 and 21 days after ischemia, dystrophin and nNOS levels recovered, and class IIa HDACs relocalized to the nucleus. In this condition, the MC1568 compound increased the number of newly formedmuscle fibers but delayed their terminal differentiation, whereas MS275 abolished the early onset of the regeneration process determining atrophy and fibrosis. The selective DIs had differential effects on the vascular compartment: MC1568 increased arteriogenesis whereasMS275 inhibited it. Capillaro-genesis did not change. Chromatin immunoprecipitations revealed that class IIaHDAC complexes bind promoters of proliferation-associated genes and of class I HDAC1 and 2, highlighting a hierarchical control between class II and I HDACs during tissue regeneration. Our findings indicate that class-selective DIs interfere with normal mouse ischemic hindlimb regeneration and suggest that their use could be limited by alteration of the regeneration process in peripheral ischemic tissues. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a diffusible signaling molecule produced by three isoforms of nitric oxide synthase, which release NO during the metabolism of the amino acid arginine. NO participates in pathophysiological responses of many different tissues, inducing concentration-dependent effect. Indeed, while low NO levels generally have protective effects, higher NO concentrations induce cytotoxic/cytostatic actions. In recent years, evidences have been accumulated unveiling S-nitrosylation as a major NO-dependent post-translational mechanism ruling gene expression. S-nitrosylation is a reversible, highly regulated phenomenon in which NO reacts with one or few specific cysteine residues of target proteins generating S-nitrosothiols. By inducing this chemical modification, NO might exert epigenetic regulation through direct effects on both DNA and histones as well as through indirect actions affecting the functions of transcription factors and transcriptional co-regulators. In this light, S-nitrosylation may also impact on cancer cell gene expression programs. Indeed, it affects different cell pathways and functions ranging from the impairment of DNA damage repair to the modulation of the activity of signal transduction molecules, oncogenes, tumor suppressors, and chromatin remodelers. Nitrosylation is therefore a versatile tool by which NO might control gene expression programs in health and disease. [ABSTRACT FROM AUTHOR]

In a mouse model of skin repair we found that the class I-IIa histone deacetylase inhibitor trichostatin A accelerated tissue regeneration. Unexpectedly, this effect was suppressed by Sirtinol, a class III histone deacetylase (HDAC) (sirtuin)-selective inhibitor. The role of sirtuins (SIRTs) was then investigated by using resveratrol and a novel SIRT1-2-3 activator, the MC2562 compound we synthesized recently. Both resveratrol and MC2562 were effective in accelerating wound repair. The local administration of natural or synthetic SIRT activators, in fact, significantly accelerated skin regeneration by increasing keratinocyte proliferation. In vitro experiments revealed that the activation of SIRTs stimulated keratinocyte proliferation via endothelial NO synthase phosphorylation and NO production. In this condition, the class I member HDAC2 was found S-nitrosylated on cysteine, a post-transduction modification associated with loss of activity and DNA binding capacity. After deacetylase inhibitor or SIRT activator treatment, ChIP showed, in fact, a significant HDAC2 detachment from the promoter region of insulin growth factor I (IGF-I), fibroblast growth factor 10 (FGF- 10), and Epithelial Growth Factor (EGF), which may be the final recipients and effectors of the SIRT-NO-HDAC signaling cascade. Consistently, the effect of SIRT activators was reduced in the presence of NG-nitro-L-arginine methyl ester (L-NAME), a general inhibitor of NO synthesis. In conclusion, the NO-dependent cross-talk among class III and I histone deacetylases suggests an unprecedented signaling pathway important for skin repair. [ABSTRACT FROM AUTHOR]

In physiopathological conditions, such as diabetes, wound healing is significantly compromised and chronic complications, including ulcers, may occur. In a mouse model of skin repair, we recently reported that wound treatment with Sirtuin activators and class I HDAC inhibitors induced keratinocyte proliferation and enhanced healing via a nitric oxide (NO) dependent mechanism. We observed an increase in total protein acetylation in the wound area, as determined by acetylation of α-tubulin and histone H3 Lysine 9. We reasoned that this process activated cell function as well as regulated gene expression to foster tissue repair. We report here that the direct activation of P300/CBP-associated factor (PCAF) by the histone acetylase activator pentadecylidenemalonate 1b (SPV-106) induced Lysine acetylation in the wound area. This intervention was sufficient to enhance repair process by a NO-independent mechanism. Hence, an impairment of PCAF and/or other GCN5 family acetylases may delay skin repair in physiopathological conditions. [ABSTRACT FROM AUTHOR]

Modulators of sirtuins are considered promising therapeutic targets for the treatment of cancer, cardiovascular, metabolic, inflammatory, and neurodegenerative diseases. Here we prepared new 1,4-dihydropyridines (DHPs) bearing changes at the C2/C6, C3/C5, C4, or N1 position. Tested with the SIRTainty procedure, some of them displayed increased SIRT1 activation with respect to the prototype 3a, high NO release in HaCat cells, and ameliorated skin repair in a mouse model of wound healing. In C2C12 myoblasts, two of them improved mitochondrial density and functions. All the effects were reverted by coadministration of compound C (9), an AMPK inhibitor, or of EX-527 (10), a SIRT1 inhibitor, highlighting the involvement of the SIRT1/AMPK pathway in the action of DHPs. Finally, tested in a panel of cancer cells, the water-soluble form of 3a, compound 8, displayed antiproliferative effects in the range of 8-35 μM and increased H4K16 deacetylation, suggesting a possible role for SIRT1 activators in cancer therapy. [ABSTRACT FROM AUTHOR]

Simple Summary: Despite the rapid advance in cancer therapies, treatment-resistant relapse remains a significant challenge in cancer treatment. Acquired resistance arises during or after treatment administration, and is usually the main contributor to relapse. For example, prostate cancer, the most frequent type of cancer in the elderly male population, frequently develops into aggressive forms resistant to chemical and hormonal therapies. In this condition, the so-called "cholinic phenotype" that is characterized by the overexpression of choline kinase alpha (CHKA) and increased phosphocholine levels leads to aberrant lipid metabolism. Our work demonstrates that CHKA, which is necessary for membrane phospholipid synthesis, is a target of the long non-coding RNA MALAT1. This study helps to further decipher how MALAT1 affects the regulation of crucial phospholipid/sphingolipid metabolic enzymes, as well as how the androgen receptor pathway is involved in MALAT1-dependent transcriptional regulation. Background. Choline kinase alpha (CHKA), an essential gene in phospholipid metabolism, is among the modulated MALAT1-targeted transcripts in advanced and metastatic prostate cancer (PCa). Methods. We analyzed CHKA mRNA by qPCR upon MALAT1 targeting in PCa cells, which is characterized by high dose-responsiveness to the androgen receptor (AR) and its variants. Metabolome analysis of MALAT1-depleted cells was performed by quantitative High-resolution 1 H-Nuclear Magnetic Resonance (NMR) spectroscopy. In addition, CHKA genomic regions were evaluated by chromatin immunoprecipitation (ChIP) in order to assess MALAT1-dependent histone-tail modifications and AR recruitment. Results. In MALAT1-depleted cells, the decrease of CHKA gene expression was associated with reduced total choline-containing metabolites compared to controls, particularly phosphocholine (PCho). Upon MALAT1 targeting a significant increase in repressive histone modifications was observed at the CHKA intron-2, encompassing relevant AR binding sites. Combining of MALAT1 targeting with androgen treatment prevented MALAT1-dependent CHKA silencing in androgen-responsive (LNCaP) cells, while it did not in hormone-refractory cells (22RV1 cells). Moreover, AR nuclear translocation and its activation were detected by confocal microscopy analysis and ChIP upon MALAT1 targeting or androgen treatment. Conclusions. These findings support the role of MALAT1 as a CHKA activator through putative association with the liganded or unliganded AR, unveiling its targeting as a therapeutic option from a metabolic rewiring perspective. [ABSTRACT FROM AUTHOR]

The epigenetic enzyme p300/CBP-associated factor (PCAF) belongs to the GCN5-related N-acetyltransferase (GNAT) family together with GCN5. Although its transcriptional and post-translational function is well characterized, little is known about its properties as regulator of cell metabolism. Here, we report the mitochondrial localization of PCAF conferred by an 85 aa mitochondrial targeting sequence (MTS) at the N-terminal region of the protein. In mitochondria, one of the PCAF targets is the isocitrate dehydrogenase 2 (IDH2) acetylated at lysine 180. This PCAF-regulated post-translational modification might reduce IDH2 affinity for isocitrate as a result of a conformational shift involving predictively the tyrosine at position 179. Site-directed mutagenesis and functional studies indicate that PCAF regulates IDH2, acting at dual level during myoblast differentiation: at a transcriptional level together with MyoD, and at a post-translational level by direct modification of lysine acetylation in mitochondria. The latter event determines a decrease in IDH2 function with negative consequences on muscle fiber formation in C2C12 cells. Indeed, a MTS-deprived PCAF does not localize into mitochondria, remains enriched into the nucleus, and contributes to a significant increase of muscle-specific gene expression enhancing muscle differentiation. The role of PCAF in mitochondria is a novel finding shedding light on metabolic processes relevant to early muscle precursor differentiation. [ABSTRACT FROM AUTHOR]

HDAC inhibitors and NO donors have already revealed independently their broad therapeutic potential in pathologic contexts. Here we further investigated the power of their combination in a single hybrid molecule. Nitrooxy groups or substituted furoxan derivatives were joined to the α-position of the pyridine ring of the selective class I HDAC inhibitor MS-275. Biochemical analysis showed that the association with the dinitrooxy compound 31 or the furoxan derivative 16 gives hybrid compounds the ability to preserve the single moiety activities. The two new hybrid molecules were then tested in a muscle differentiation assay. The hybrid compound bearing the moiety 31 promoted the formation of large myotubes characterized by highly multinucleated fibers, possibly due to a stimulation of myoblast fusion, as implicated by the strong induction of myomaker expression. Thanks to their unique biological features, these compounds may represent new therapeutic tools for cardiovascular, neuromuscular and inflammatory diseases. [ABSTRACT FROM AUTHOR]

Organ-specific mesenchymal cells naturally reside in the stroma, where they are exposed to some environmental variables affecting their biology and functions. Risk factors such as diabetes or aging influence their adaptive response. In these cases, permanent epigenetic modifications may be introduced in the cells with important consequences on their local homeostatic activity and therapeutic potential. Numerous results suggest that mesenchymal cells, virtually present in every organ, may contribute to tissue regeneration mostly by paracrine mechanisms. Intriguingly, the heart is emerging as a source of different cells, including pericytes, cardiac progenitors, and cardiac fibroblasts. According to phenotypic, functional, and molecular criteria, these should be classified as mesenchymal cells. Not surprisingly, in recent years, the attention on these cells as therapeutic tools has grown exponentially, although only very preliminary data have been obtained in clinical trials to date. In this review, we summarized the state of the art about the phenotypic features, functions, regenerative properties, and clinical applicability of mesenchymal cells, with a particular focus on those of cardiac origin. [ABSTRACT FROM AUTHOR]

The inhibition of human DNA Methyl Transferases ( DNMT) is a novel promising approach to address the epigenetic dysregulation of gene expression in different diseases. Inspired by the validated virtual screening hit NSC137546, a series of N-benzoyl amino acid analogues was synthesized and obtained compounds were assessed for their ability to inhibit DNMT-dependent DNA methylation in vitro. The biological screening allowed the definition of a set of preliminary structure-activity relationships and the identification of compounds promising for further development. Among the synthesized compounds, L-glutamic acid derivatives 22, 23, and 24 showed the highest ability to prevent DNA methylation in a total cell lysate. Compound 22 inhibited DNMT1 and DNMT3A activity in a concentration-dependent manner in the micromolar range. In addition, compound 22 proved to be stable in human serum and it was thus selected as a starting point for further biological studies. [ABSTRACT FROM AUTHOR]

The brains of teleost fish show extensive adult neurogenesis and neuronal regeneration. The patterns of gene regulation during fish brain aging are unknown. The short-lived teleost fish Nothobranchius furzeri shows markers of brain aging including reduced learning performances, gliosis, and reduced adult neurogenesis. We used RNA-seq to quantify genome-wide transcript regulation and sampled five different time points to characterize whole-genome transcript regulation during brain aging of N. furzeri. Comparison with human datasets revealed conserved up-regulation of ribosome, lysosome, and complement activation and conserved down-regulation of synapse, mitochondrion, proteasome, and spliceosome. Down-regulated genes differ in their temporal profiles: neurogenesis and extracellular matrix genes showed rapid decay, synaptic and axonal genes a progressive decay. A substantial proportion of differentially expressed genes (~40%) showed inversion of their temporal profiles in the last time point: spliceosome and proteasome showed initial down-regulation and stress-response genes initial up-regulation. Extensive regulation was detected for chromatin remodelers of the DNMT and CBX families as well as members of the polycomb complex and was mirrored by an up-regulation of the H3K27me3 epigenetic mark. Network analysis showed extensive coregulation of cell cycle/ DNA synthesis genes with the uncharacterized zinc-finger protein ZNF367 as central hub. In situ hybridization showed that ZNF367 is expressed in neuronal stem cell niches of both embryonic zebrafish and adult N. furzeri. Other genes down-regulated with age, not previously associated with adult neurogenesis and with similar patterns of expression are AGR2, DNMT3A, KRCP, MEX3A, SCML4, and CBX1. CBX7, on the other hand, was up-regulated with age. [ABSTRACT FROM AUTHOR]

Chromosome 1p36 deletion syndrome is one of the most common terminal deletions observed in humans and is related to congenital heart disease (CHD). However, the 1p36 genes that contribute to heart disease have not been clearly delineated. Human CASZ1 gene localizes to 1p36 and encodes a zinc finger transcription factor. Casz1 is required for Xenopus heart ventral midline progenitor cell differentiation. Whether Casz1 plays a role during mammalian heart development is unknown. Our aim is to determine 1p36 gene CASZ1 function at regulating heart development in mammals. We generated a Casz1 knockout mouse using Casz1-trapped embryonic stem cells. Casz1 deletion in mice resulted in abnormal heart development including hypoplasia of myocardium, ventricular septal defect, and disorganized morphology. Hypoplasia of myocardium was caused by decreased cardiomyocyte proliferation. Comparative genome-wide RNA transcriptome analysis of Casz1 depleted embryonic hearts identifies abnormal expression of genes that are critical for muscular system development and function, such as muscle contraction genes TNNI2, TNNT1, and CKM; contractile fiber gene ACTA1; and cardiac arrhythmia associated ion channel coding genes ABCC9 and CACNA1D. The transcriptional regulation of some of these genes by Casz1 was also found in cellular models. Our results showed that loss of Casz1 during mouse development led to heart defect including cardiac noncompaction and ventricular septal defect, which phenocopies 1p36 deletion syndrome related CHD. This suggests that CASZ1 is a novel 1p36 CHD gene and that the abnormal expression of cardiac morphogenesis and contraction genes induced by loss of Casz1 contributes to the heart defect. [ABSTRACT FROM AUTHOR]

Our understanding of epigenetic mechanisms important for embryonic vascular development and cardiovascular differentiation is still in its infancy. Although molecular analyses, including massive genome sequencing and/or in vitro/in vivo targeting of specific gene sets, has led to the identification of multiple factors involved in stemness maintenance or in the early processes of embryonic layers specification, very little is known about the epigenetic commitment to cardiovascular lineages. The object of this review will be to outline the state of the art in this field and trace the perspective therapeutic consequences of studies aimed at elucidating fundamental epigenetic networks. Special attention will be paid to the emerging role of nitric oxide in this field. [ABSTRACT FROM AUTHOR]

Wanting to explore the epigenetic basis of Duchenne cardiomyopathy, we found that global histone acetylase activity was abnormally elevated and the acetylase P300/CBP-associated factor (PCAF) coimmunoprecipitated with connexin 43 (Cx43), which was Nϵ-lysine acetylated and lateralized in mdx heart. This observation was paralleled by Cx43 dissociation from N-cadherin and zonula occludens 1, whereas pp60-c-Src association was unaltered. In vivo treatment of mdx with the pan-histone acetylase inhibitor anacardic acid significantly reduced Cx43 Nϵ-lysine acetylation and restored its association to GAP junctions (GJs) at intercalated discs. Noteworthy, in normal as well as mdx mice, the class IIa histone deacetylases 4 and 5 constitutively colocalized with Cx43 either at GJs or in the lateralized compartments. The class I histone deacetylase 3 was also part of the complex. Treatment of normal controls with the histone deacetylase pan-inhibitor suberoylanilide hydroxamic acid (MC1568) or the class IIa-selective inhibitor 3-{4-[3-(3-fluorophenyl)-3-oxo-1-propen-1-yl]-1-methyl-1H-pyrrol-2-yl}-N-hydroxy-2-propenamide (MC1568) determined Cx43 hyperacetylation, dissociation from GJs, and distribution along the long axis of ventricular cardiomyocytes. Consistently, the histone acetylase activator pentadecylidenemalonate 1b (SPV106) hyperacetylated cardiac proteins, including Cx43, which assumed a lateralized position that partly reproduced the dystrophic phenotype. In the presence of suberoylanilide hydroxamic acid, cell to cell permeability was significantly diminished, which is in agreement with a Cx43 close conformation in the consequence of hyperacetylation. Additional experiments, performed with Cx43 acetylation mutants, revealed, for the acetylated form of the molecule, a significant reduction in plasma membrane localization and a tendency to nuclear accumulation. These results suggest that Cx43 Nϵ-lysine acetylation may have physiopathological consequences for cell to cell coupling and cardiac function. [ABSTRACT FROM AUTHOR]

Aims: The effect of histone deacetylase inhibitors on dystrophic heart function is not established. To investigate this aspect, dystrophic mdx mice and wild-type (WT) animals were treated 90 days either with suberoylanilide hydroxamic acid (SAHA, 5 mg/kg/day) or with an equivalent amount of vehicle. [ABSTRACT FROM PUBLISHER]

Abstract: Histone deacetylases (HDACs) are enzymes with a pleiotropic range of intracellular localizations and actions. They are principally involved in the withdrawal of acetyl-groups from a large number of nuclear and cytoplasmic proteins including nuclear core histones as well as cytoskeletal proteins and metabolically relevant enzymes. Initial findings indicated that HDAC inhibitors (DIs) could be successfully applied in a variety of cancer treatment protocols as a consequence of their anti-proliferative and pro-apoptotic properties. Recent observations, however, enlightened the important therapeutic effects of DIs in experimental animal models for arthritis, neurodegenerative and neuromuscular disorders, heart ischemia, cardiac hypertrophy, heart failure and arrhythmias. A small number of clinical trials are now open or planned for the near future to verify the therapeutic properties of DIs in non-cancer-related diseases. This review summarizes some of the most important observations and concepts aroused by the most recent experimental application of DIs to neuromuscular and cardiac diseases. [Copyright &y& Elsevier]

Classical Hodgkin lymphoma (cHL) is one of the most common malignant lymphomas in Western Europe. The nodular sclerosing subtype of cHL (NS cHL) is characterized by a proliferation of fibroblasts in the tumor microenvironment, leading to fibrotic bands surrounding the lymphoma infiltrate. Several studies have described a crosstalk between the tumour cells of cHL, the Hodgkin- and Reed-Sternberg (HRS) cells, and cancer-associated fibroblasts. However, to date a deep molecular characterization of these fibroblasts is lacking. Thus, the aim of the present study is a comprehensive characterization of these fibroblasts. Gene expression profiling and methylation profiles of fibroblasts isolated from primary lymph node suspensions revealed persistent differences between fibroblasts obtained from NS cHL and lymphadenitis. NS cHL derived fibroblasts exhibit a myofibroblastic phenotype characterized by myocardin (MYOCD) expression. Moreover, TIMP3, an inhibitor of matrix metalloproteinases, was strongly upregulated in NS cHL fibroblasts, likely contributing to the accumulation of collagen in sclerotic bands of NS cHL. As previously shown for other types of cancer-associated fibroblasts, treatment by luteolin could reverse this fibroblast phenotype and decrease TIMP3 secretion. NS cHL fibroblasts showed enhanced proliferation when they were exposed to soluble factors released from HRS cells. For HRS cells, soluble factors from fibroblasts were not sufficient to protect them from Brentuximab-Vedotin induced cell death. However, HRS cells adherent to fibroblasts were protected from Brentuximab-Vedotin induced injury. In summary, we confirm the importance of fibroblasts for HRS cell survival and identify TIMP3 which probably contributes as a major factor to the typical fibrosis observed in NS cHL. [ABSTRACT FROM AUTHOR]

Aging associates with progressive loss of skeletal muscle function, sometimes leading to sarcopenia, a process characterized by impaired mobility and weakening of muscle strength. Since aging associates with profound epigenetic changes, epigenetic landscape alteration analysis in the skeletal muscle promises to highlight molecular mechanisms of age-associated alteration in skeletal muscle. This study was conducted exploiting the short-lived turquoise killifish Nothobranchius furzeri (Nfu), a relatively new model for aging studies. The epigenetic analysis suggested a less accessible and more condensed chromatin in old Nfu skeletal muscle. Specifically, an accumulation of heterochromatin regions was observed as a consequence of increased levels of H3K27me3, HP1α, polycomb complex subunits, and senescence-associated heterochromatic foci (SAHFs). Consistently, euchromatin histone marks, including H3K9ac, were significantly reduced. In this context, integrated bioinformatics analysis of RNASeq and ChIPSeq, related to skeletal muscle of Nfu at different ages, revealed a down-modulation of genes involved in cell cycle, differentiation, and DNA repair and an up-regulation of inflammation and senescence genes. Undoubtedly, more studies are needed to disclose the detailed mechanisms; however, our approach enlightened unprecedented features of Nfu skeletal muscle aging, potentially associated with swimming impairment and reduced mobility typical of old Nfu. [ABSTRACT FROM AUTHOR]

NKp46 (CD335) is a surface receptor shared by both human and mouse natural killer (NK) cells and innate lymphoid cells (ILCs) that transduces activating signals necessary to eliminate virus-infected cells and tumors. Here, we describe a spontaneous point mutation of cysteine to arginine (C14R) in the signal peptide of the NKp46 protein in congenic Ly5.1 mice and the newly generated NCRB6C14R strain. Ly5.1C14R NK cells expressed similar levels of Ncr1 mRNA as C57BL/6, but showed impaired surface NKp46 and reduced ability to control melanoma tumors in vivo. Expression of the mutant NKp46C14R in 293T cells showed that NKp46 protein trafficking to the cell surface was compromised. Although Ly5.1C14R mice had normal number of NK cells, they showed an increased number of early maturation stage NK cells. CD49a+ILC1s were also increased but these cells lacked the expression of TRAIL. ILC3s that expressed NKp46 were not detectable and were not apparent when examined by T-bet expression. Thus, the C14R mutation reveals that NKp46 is important for NK cell and ILC differentiation, maturation and function. Significance Innate lymphoid cells (ILCs) play important roles in immune protection. Various subsets of ILCs express the activating receptor NKp46 which is capable of recognizing pathogen derived and tumor ligands and is necessary for immune protection. Here, we describe a spontaneous point mutation in the signal peptide of the NKp46 protein in congenic Ly5.1 mice which are widely used for tracking cells in vivo. This Ncr1 C14R mutation impairs NKp46 surface expression resulting in destabilization of Ncr1 and accumulation of NKp46 in the endoplasmic reticulum. Loss of stable NKp46 expression impaired the maturation of NKp46+ ILCs and altered the expression of TRAIL and T-bet in ILC1 and ILC3, respectively. [ABSTRACT FROM AUTHOR]