CCAAT/Enhancer-Binding Protein Homologous Protein (CHOP) Deficiency Attenuates Heatstroke-Induced Intestinal Injury

ZBP1 and heatstroke

Heatstroke, which is associated with circulatory failure and multiple organ dysfunction, is a heat stress-induced life-threatening condition characterized by a raised core body temperature and central nervous system dysfunction. As global warming continues to worsen, heatstroke is expected to become the leading cause of death globally. Despite the severity of this condition, the detailed mechanisms that underlie the pathogenesis of heatstroke still remain largely unknown. Z-DNA-binding protein 1 (ZBP1), also referred to as DNA-dependent activator of IFN-regulatory factors (DAI) and DLM-1, was initially identified as a tumor-associated and interferon (IFN)-inducible protein, but has recently been reported to be a Z-nucleic acid sensor that regulates cell death and inflammation; however, its biological function is not yet fully understood. In the present study, a brief review of the main regulators is presented, in which the Z-nucleic acid sensor ZBP1 was identified to be a significant factor in regulating the pathological characteristics of heatstroke through ZBP1-dependent signaling. Thus, the lethal mechanism of heatstroke is revealed, in addition to a second function of ZBP1 other than as a nucleic acid sensor.

Depletion of chop suppresses procedural apoptosis and enhances innate immunity in loach Misgurnus anguillicaudatus under ammonia nitrogen stress

Ammonia nitrogen is highly toxic to fish, and it can easily cause fish poisoning or even high mortality. So far, many studies have been conducted on the damages to fish under ammonia nitrogen stress. However, there are few studies of ammonia tolerance improvement in fish. In this study, the effects of ammonia nitrogen exposure on apoptosis, endoplasmic reticulum (ER) stress, and immune cells in loach Misgurnus anguillicaudatus were investigated. Loaches (60 d post fertilization) were exposed to different concentrations of NH4Cl, and their survival rates were examined every 6 h. The results showed that high-concentration and long-time NH4Cl exposure (20 mM + 18 h; 15 mM + 36 h) induced apoptosis and gill tissue damages, finally causing a decline in survival. chop plays an important role in ER stress-induced apoptosis, and thus we constructed a model of chop-depleted loach by using CRISPR/Cas9 technology to investigate its response to ammonia nitrogen stress. The results showed that ammonia nitrogen stress down-regulated the expressions of apoptosis-related genes in chop+/- loach gills, while wildtype (WT) exhibited an opposite gene expression regulation pattern, suggesting that the depletion of chop suppressed apoptosis level. In addition, chop+/- loach showed a larger number of immunity-related cells and higher survival rate than WT under the NH4Cl exposure, indicating that the inhibition of chop function strengthened the innate immune barrier in general, thus increasing survival. Our findings provide the theoretical basis for developing high ammonia nitrogen-tolerant germplasm with aquaculture potential.

Tofacitinib enhances IGF1 via inhibiting STAT6 transcriptionally activated-miR-425-5p to ameliorate inflammation in RA-FLS

Rheumatoid arthritis (RA) is a systemic autoimmune disease, which has been reported closely associated with the dysfunction of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. This study aims to explore the potential therapeutic effect of Tofacitinib, a putative JAK/STAT inhibitor, in RA. Tofacitinib suppressed proliferation and accelerated apoptosis of rheumatoid arthritis synovial fibroblasts (RA-FLS) as confirmed by CCK-8, EdU and Western blot assays. Tofacitinib significantly inhibited expression of pro-inflammatory factors including tumor necrosis factor-α (TNF-α), vascular endothelial growth factor A, matrix metalloproteinase 1, matrix metalloproteinase 3, interleukin-6 and interferon gamma in RA-FLS cells. mechanistically, tofacitinib decreased signal transducer and activator of transcription 6 (STAT6), which transcriptionally activates miR-425-5p, and thus increased insulin like growth factor 1 (IGF1) expression, a target of miR-425-5p in RA-FLS. Overexpression of STAT6 restored the expression of pro-inflammatory factors and proliferation inhibited by Tofacitinib in RA-FLS. Overall, Tofacitinib exerted inhibitory effect on proliferation and inflammation of RA-FLS through modulating STAT6/miR-425-5p/IGF1 signal axis. These findings shed light on the novel strategies for improving RA.

Protein palmitoylation-mediated palmitic acid sensing causes blood-testis barrier damage via inducing ER stress

Blood-testis barrier (BTB) damage promotes spermatogenesis dysfunction, which is a critical cause of male infertility. Dyslipidemia has been correlated with male infertility, but the major hazardous lipid and the underlying mechanism remains unclear. In this study, we firstly discovered an elevation of palmitic acid (PA) and a decrease of inhibin B in patients with severe dyszoospermia, which leaded us to explore the effects of PA on Sertoli cells. We observed a damage of BTB by PA. PA penetration to endoplasmic reticulum (ER) and its damage to ER structures were exhibited by microimaging and dynamic observation, and consequent ER stress was proved to mediate PA-induced Sertoli cell barrier disruption. Remarkably, we demonstrated a critical role of aberrant protein palmitoylation in PA-induced Sertoli cell barrier dysfunction. An ER protein, Calnexin, was screened out and was demonstrated to participate in this process, and suppression of its palmitoylation showed an ameliorating effect. We also found that ω-3 poly-unsaturated fatty acids down-regulated Calnexin palmitoylation, and alleviated BTB dysfunction. Our results indicate that dysregulated palmitoylation induced by PA plays a pivotal role in BTB disruption and subsequent spermatogenesis dysfunction, suggesting that protein palmitoylation might be therapeutically targetable in male infertility.

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An elevation of circulating PA was identified in patients with severe dyszoospermia.

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PA-induced over-palmitoylation in Sertoli cells leads to ER stress and BTB damage.

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The palmitoylation of the ER protein Calnexin regulates Sertoli cell barrier function.

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ω-3 PUFAs ameliorate PA-induced damage and over-palmitoylation in Sertoli cells.