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Salinity is an important environmental factor in microbial ecology for affecting the microbial communities in diverse environments. Understanding the salinity adaptation mechanisms of a microbial community is a significant issue, while most previous studies only covered a narrow salinity range. Here, variations in seawater prokaryotic communities during the whole salt drying progression (salinity from 3% to 25%) were investigated. According to high‐throughput sequencing results, the diversity, composition, and function of seawater prokaryotic communities varied significantly along the salinity gradient, expressing as decreased diversity, enrichment of some halophilic archaea, and powerful nitrate reduction in samples with high salt concentrations. More importantly, a sudden and dramatic alteration of prokaryotic communities was observed when salinity reached 16%, which was recognized as the change point. Combined with the results of network analysis, we found the increasing of complexity but decreasing of stability in prokaryotic communities when salinity exceeded the change point. Moreover, prokaryotic communities became more deterministic when salinity exceeded the change point due to the niche adaptation of halophilic species. Our study showed that substantial variations in seawater prokaryotic communities along an extremely wide salinity gradient, and also explored the underlying mechanisms regulating these changes. [ABSTRACT FROM AUTHOR]

Summary: Nowadays, the true economic and nutritional value of food is underpinned by both origin and quality traits, more often expressed as increased quality benefits derived from the origin source. Gut microbiota contribute to food metabolism and host health, therefore, it may be suitable as a qualifying indicator of origin and quality of economic species. Here, we investigated relationships between the gut microbiota of the sea cucumber (Apostichopus japonicus), a valuable aquaculture species in Asia, with their origins and quality metrics. Based on data from 287 intestinal samples, we generated the first biogeographical patterns for A. japonicus gut microbiota from origins across China. Importantly, A. japonicus origins were predicted using the random forest model that was constructed using 20 key gut bacterial genera, with 97.6% accuracy. Furthermore, quality traits such as saponin, fat and taurine were also successfully predicted by random forest models based on gut microbiota, with approximately 80% consistency between predicted and true values. We showed that substantial variations existed in the gut microbiota and quality variables in A. japonicus across different origins, and we also demonstrated the great potential of gut microbiota to track A. japonicus origins and predict their quality traits. [ABSTRACT FROM AUTHOR]

Background and Purpose: The protein V‐domain immunoglobulin suppressor of T‐cell activation (VISTA) is a novel immune‐checkpoint molecule that belongs to the B7 family and regulates a broad spectrum of immune responses. So far, low MW compounds targeting VISTA for the treatment of autoimmune diseases or inflammation, have not been identified. Experimental Approach We developed a homology modelling for VISTA 3D structure and subsequent virtual screening for low MW ligands binding to VISTA. Visualization of the binding postures of docked ligands with protein VISTA indicated that compound M351‐0056 targeted VISTA. The biological activities of compound M351‐0056 targeting VISTA were investigated in vitro using monocytes and T cells and in vivo, using mice with imiquimod‐induced dermatitis. Key Results: The KD value of M351‐0056 for human VISTA‐extracellular domain was 12.60 ± 3.84 μM as assessed by microscale thermophoresis. M351‐0056 decreased cytokine secretion from PBMCs or human CD4+ T cells, suppressed proliferation of PBMCs and enhanced expression of Foxp3+ T cells. These effects of M351‐0056 modulating VISTA involved the JAK2–STAT2 pathway. Daily administration of M351‐0056 ameliorated imiquimod‐induced psoriasis‐like dermatitis. Expression of mRNA and protein of inflammatory cytokines in psoriatic lesions was decreased after M351‐0056 treatment. Conclusion and Implications: The compound M351‐0056 showed high affinity for VISTA and may modulate its immune function in vitro and in vivo. Our finding provides a lead compound for therapeutically enhancing VISTA‐mediated pathways to benefit the treatment of autoimmune diseases or inflammation. [ABSTRACT FROM AUTHOR]

Background: Transforming growth factor‐β‐activated kinase 1 (TAK1) plays a key role in regulating fibroblast and myoblast proliferation and differentiation. However, the TAK1 changes associated with Duchenne muscular dystrophy (DMD) are poorly understood, and it remains unclear how TAK1 regulation could be exploited to aid the treatment of this disease. Methods: Muscle biopsies were obtained from control donors or DMD patients for diagnosis (n = 6 per group, male, 2–3 years, respectively). Protein expression of phosphorylated TAK1 was measured by western blot and immunofluorescence analysis. In vivo overexpression of TAK1 was performed in skeletal muscle to assess whether TAK1 is sufficient to induce or aggravate atrophy and fibrosis. To explore whether TAK1 inhibition protects against muscle damage, mdx (loss of dystrophin) mice were treated with adeno‐associated virus (AAV)‐short hairpin TAK1 (shTAK1) or NG25 (a TAK1 inhibitor). Serum analysis, skeletal muscle performance and histology, muscle contractile function, and gene and protein expression were performed. Results: We found that TAK1 was activated in the dystrophic muscles of DMD patients (n = 6, +72.2%, P < 0.001), resulting in fibrosis (+65.9% for fibronectin expression, P < 0.001) and loss of muscle fibres (−32.5%, P < 0.01). Moreover, TAK1 was activated by interleukin‐1β, tumour necrosis factor‐α, and transforming growth factor‐β1 (P < 0.01). Overexpression of TAK1 by AAV vectors further aggravated fibrosis (n = 8, +39.6% for hydroxyproline content, P < 0.01) and exacerbated muscle wasting (−31.6%, P < 0.01) in mdx mice; however, these effects were reversed in mdx mice by treatment with AAV‐short hairpin TAK1 (shTAK1) or NG25 (a TAK1 inhibitor). The molecular mechanism underlying these effects may be related to the prevention of TAK1‐mediated transdifferentiation of myoblasts into fibroblasts, thereby reducing fibrosis and increasing myoblast differentiation. Conclusions: Our findings show that TAK1 activation exacerbated fibrosis and muscle degeneration and that TAK1 inhibition can improve whole‐body muscle quality and the function of dystrophic skeletal muscle. Thus, TAK1 inhibition may constitute a novel therapy for DMD. [ABSTRACT FROM AUTHOR]

Background: Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by the loss of dystrophin, which results in inflammation, fibrosis, and the inhibition of myoblast differentiation in skeletal muscle. Catalpol, an iridoid glycoside, improves skeletal muscle function by enhancing myogenesis; it has potential to treat DMD. We demonstrate the positive effects of catalpol in dystrophic skeletal muscle. Methods: mdx (loss of dystrophin) mice (n = 18 per group) were treated with catalpol (200 mg/kg) for six consecutive weeks. Serum analysis, skeletal muscle performance and histology, muscle contractile function, and gene and protein expression were performed. Molecular docking and ligand–target interactions, RNA interference, immunofluorescence, and plasmids transfection were utilized to explore the protective mechanism in DMD by which catalpol binding with transforming growth factor‐β–activated kinase 1 (TAK1) in skeletal muscle. Results: Six weeks of catalpol treatment improved whole‐body muscle health in mdx mice, which was characterized by reduced plasma creatine kinase (n = 18, −35.1%, P < 0.05) and lactic dehydrogenase (n = 18, −10.3%, P < 0.05) activity. These effects were accompanied by enhanced grip strength (n = 18, +25.4%, P < 0.05) and reduced fibrosis (n = 18, −29.0% for hydroxyproline content, P < 0.05). Moreover, catalpol treatment protected against muscle fatigue and promoted muscle recovery in the tibialis anterior (TA) and diaphragm (DIA) muscles (n = 6, +69.8%, P < 0.05 and + 74.8%, P < 0.001, respectively), which was accompanied by enhanced differentiation in primary myoblasts from DMD patients (n = 6, male, mean age: 4.7 ± 1.9 years) and mdx mice. In addition, catalpol eliminated p‐TAK1 overexpression in mdx mice (n = 12, −21.3%, P < 0.05) and primary myoblasts. The catalpol‐induced reduction in fibrosis and increased myoblast differentiation resulted from the inhibition of TAK1 phosphorylation, leading to reduced myoblast trans‐differentiation into myofibroblasts. Catalpol inhibited the phosphorylation of TAK1 by binding to TAK1, possibly at Asp‐206, Thr‐208, Asn‐211, Glu‐297, Lys‐294, and Tyr‐293. Conclusions: Our findings show that catalpol and TAK1 inhibitors substantially improve whole‐body muscle health and the function of dystrophic skeletal muscles and may provide a novel therapy for DMD. [ABSTRACT FROM AUTHOR]

Abstract: The monocytic MDSC (M‐MDSC) is one of the major types of MDSCs, which play important roles in suppression of antitumor immunity. However, the mechanisms underlying how M‐MDSCs so heavily accumulate in patients with cancer are still poorly understood. The purpose of this study was to identify miRNAs that regulate the proliferation and differentiation of M‐MDSCs. Microarray analysis was performed to identify differentially expressed miRNAs between tumor‐induced M‐MDSCs (TM‐MDSCs) and their counterparts from tumor‐free mice. The miRNAs and their target genes that regulate the proliferation and differentiation of myeloid cells were predicted by bioinformatics analysis and validated by RT‐qPCR. Luciferase reporter assays were used to analyze the relationships between miRNAs and target genes. Overexpression of candidate miRNAs and target genes in myeloid cells was conducted to verify their functions in cell proliferation, differentiation, and apoptosis. Our data showed that miR‐486 was overexpressed in TM‐MDSCs. Cebpa was predicted to be one of the target genes of miR‐486 that regulates the proliferation of myeloid cells. Expression of Cebpa was inversely correlated with miR‐486 in TM‐MDSCs, and we found that overexpression of miR‐486 suppressed the expression of Cebpa in both 293T cells determined by luciferase reporter assays and in myeloid cells determined by RT‐qPCR. Overexpression of miR‐486 promoted proliferation and suppressed apoptosis in myeloid cells, as opposed to overexpression of Cebpa, which promoted the opposing phenotype. Overexpression of either miR‐486 or Cebpa inhibited differentiation of myeloid cells. This study indicates that miR‐486 promotes proliferation and suppresses apoptosis in myeloid cells by targeting Cebpa in vitro, suggesting that miR‐486 and Cebpa might be involved in the expansion of TM‐MDSCs in tumor‐bearing mice. [ABSTRACT FROM AUTHOR]

Understanding how pathogens invade and become established in novel host populations is central to the ecology and evolution of infectious disease. Influenza viruses provide unique opportunities to study these processes in nature because of their rapid evolution, extensive surveillance, large data sets and propensity to jump species boundaries. H5N1 highly pathogenic avian influenza virus (HPAIV) is a major animal pathogen and public health threat. The virus is of particular importance in Indonesia, causing severe outbreaks among poultry and sporadic human infections since 2003. However, little is known about how H5N1 HPAIV emerged and established in Indonesia. To address these questions, we analysed Indonesian H5N1 HPAIV gene sequences isolated during 2003-2007. We find that the virus originated from a single introduction into East Java between November 2002 and October 2003. This invasion was characterized by an initially rapid burst of viral genetic diversity followed by a steady rate of lineage replacement and the maintenance of genetic diversity. Several antigenic sites in the haemagglutinin gene were subject to positive selection during the early phase, suggesting that host-immune-driven selection played a role in host adaptation and expansion. Phylogeographic analyses show that after the initial invasion of H5N1, genetic variants moved both eastwards and westwards across Java, possibly involving long-distance transportation by humans. The phylodynamics we uncover share similarities with other recently studied viral invasions, thereby shedding light on the ecological and evolutionary processes that determine disease emergence in a new geographical region. [ABSTRACT FROM AUTHOR]

Surrogate markers for the Alzheimer disease (AD)-associated 42-amino acid form of amyloid-β (Aβ42) have been sought because they may aid in the diagnosis of AD and for clarification of disease pathogenesis. Here, we demonstrate that human cerebrospinal fluid (CSF) contains three APLP1-derived Aβ-like peptides (APL1β) that are generated by β- and γ-cleavages at a concentration of ∼4.5 nM. These novel peptides, APL1β25, APL1β27 and APL1β28, were not deposited in AD brains. Interestingly, most γ-secretase modulators (GSMs) and familial AD-associated presenilin1 mutants that up-regulate the relative production of Aβ42 cause a parallel increase in the production of APL1β28 in cultured cells. Moreover, in CSF from patients with pathological mutations in presenilin1 gene, the relative APL1β28 levels are higher than in non-AD controls, while the relative Aβ42 levels are unchanged or lower. Most strikingly, the relative APL1β28 levels are higher in CSF from sporadic AD patients (regardless of whether they are at mild cognitive impairment or AD stage), than those of non-AD controls. Based on these results, we propose the relative level of APL1β28 in the CSF as a candidate surrogate marker for the relative level of Aβ42 production in the brain. [ABSTRACT FROM AUTHOR]

Background: Alzheimer’s disease associated βAPP is sequentially endoproteolyzed by α/β-secretase and γ-cleavage. In the process, extracellular shedding by α-secretase (ADAM 9/10/17) or β-secretase (BACE 1/2) at position L17 or D1 (Aβ numbering) are prerequisites for the generation of P3 or Aβ, respectively. In addition, several alternative extracellular cleavage sites in βAPP have been reported at position I−6, V−3, R5, E11, F20, and A21. Among these sites, position R5 is considered to be cleaved by α-secretase-like activity, whereas position E11, F20 and A21 are cleaved by β-secretase. Therefore, extracellular shedding of βAPP is thought to be mediated exclusively by α/β-secretase activities. However, so far the characteristics of cleavages at position V−3 and I−6 are not well understood. The aim of this study is to characterize these two cleavages of βAPP. Methods: We analyzed the conditioned media of βAPP wt or sw expressing cells with or without pharmacological agents. Results: Here, we show that the cleavage at position I−6 of βAPP has characteristics distinct from that of α/β-secretase, while the cleavage at V−3 seems to be mediated by β-secretase. Although inhibition of endocytosis enhances the cleavages at both V−3 and I−6, PMA, an α-secretase stimulator, treatment enhances neither of these cleavages. Interestingly, a β-secretase inhibitor, z-VLL-CHO, suppressed V−3 but not I−6 cleavage. The pathological βAPP Swedish mutant adjacent to the cleavage sites shows similar effects. Conclusions: Our data demonstrate that neither α nor β-secretase undergoes extracellular shedding at I−6 of βAPP. Therefore, our data may indicate a novel alternative βAPP degradation pathway which is up-regulated upon low level of endocytosis. [ABSTRACT FROM AUTHOR]

R2862 --> The ventromedial nucleus of the hypothalamus (VMH) was the first site to be recognized as a key player in body weight regulation. The VMH has also been implicated in brown adipose tissue (BAT) thermoregulation, sympathetic nerve activity and glucose homeostasis. Within the VMH, steroidogenic factor 1 (SF1) neurons expressing receptors that binds various hormonal signals have emerged as critical mediators of metabolic control. In this study, we assessed how Designer Receptors Exclusively Activated by Designer Drugs (DREADD)‐mediated activation of SF1 neurons affect food intake, glucose homeostasis, insulin sensitivity and sympathetic nerve activity. Using SF1Cre+ male mice, we found that DREADD‐mediated activation of SF1 neurons caused a dramatic feeding stimulatory response within 4h of CNO injection (0.75±0.16g relative to 0.13±0.07g in control SF1Cre‐ mice, P<0.05). Interestingly, in male mice SF1 neuron‐specific activation induces BAT sympathetic nerve activation without affecting renal sympathetic tone. In female mice, food intake and BAT sympathetic traffic were not altered after activation of SF1 neurons. On the other hand, insulin sensitivity was significantly attenuated only in females following SF1 neuron activation (100.20±13.07mmol/L vs 25.25±12.15mmol/L in control at 2h, P<0.05). Glucose homeostasis was not affected upon SF1 neuron activation in both male and female mice. Notably, activation of SF1 neurons increased blood pressure and heart rate in mice fed high fat/high sucrose diet. These results show that VMH SF1 neurons regulate food intake, sympathetic tone and insulin sensitivity in a sex‐specific manner and that SF1 neurons contribute to regulation of cardiovascular function. Our findings provide new insight into a previously unappreciated role of VMH SF1 neuron in the control of regional sympathetic nerve traffic and cardiovascular function. [ABSTRACT FROM AUTHOR]