Expression of SOCS3 throughout liver regeneration is not regulated by DNA methylation

BACKGROUND:While suppressor of cytokine signaling 3(SOCS3) plays a crucial role in suppressing dysplasia and tumorigenesis,it also offers a typical instance of DNA methylation in the regulation of gene transcription,since the promoter region of the SOCS3 gene is rich in CpG islands(CGIs).During liver regeneration initiated by partial hepatectomy,SOCS3 acts as a suppressor to balance the acute-phase response and terminate the regeneration.This study aimed to determine whether the variation of SOCS3 expression throughout liver regeneration is also regulated by its DNA methylation.METHODS:We established a 70% partial hepatectomy mouse model and the animals were sacrificed at indicated times to assess the SOCS3 expression.We performed bisulfite sequencing PCR and DNA sequencing to investigate the detailed cytosine methylation in the SOCS3 gene.RESULTS:Within the promoter sequence,58 CGIs were identified and 30 were found variously methylated before or after operation;however,methylation remained at a very low level.No evidence indicated that the total methylation level or the methylation of any CpG site regularly changed throughout liver regeneration.CONCLUSION:DNA methylation or demethylation seems to be a relatively stable modification of cytosine,but not a dynamic and reversible process to regulate gene transcription in daily and acute pathophysiological events.

Moxibustion regulates T-regulatory/T-helper 17 cell balance by modulating the microRNA-221/suppressor of cytokine signaling 3 axis in a mouse model of rheumatoid arthritis

Objective Rheumatoid arthritis(RA)progression is associated with the balance of T-regulatory(Treg)and T-helper 17(Th17)cells,while the role of microRNAs(miRs)in regulating Treg/Th17 cell balance has not been clarified.This study aimed to assess whether moxibustion could regulate Treg/Th17 cell balance by modulating the miR-221/suppressor of cytokine signaling 3(SOCS3)axis in the RA mouse model.Methods A mouse model of collagen-induced arthritis(CIA)was established in male DBA/1J mice.Twenty-two days after CIA induction,the mice received daily treatment with moxibustion for 12 times.Pathological scores were assessed according to the levels of synovial hyperplasia.The expression levels of cytokines interleukin(IL)-1β,IL-6,tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),IL-17 and IL-10 were analyzed in serum by enzyme-linked immunosorbent assay.The cluster of differentiation 4(CD4+)splenocytes was analyzed by fluorescence-activated cell sorting.The expression levels of RA-related miRs and target genes were subsequently detected,and the target of miR-221 was confirmed by the dual-luciferase reporter assay.Results It was revealed that moxibustion treatment decreased the pathological scores and downregulated the expression levels of IL-1β,IL-6,TNF-α,IFN-γand IL-17,while upregulated the expression level of IL-10.The Treg/Th17 cell balance was regulated by moxibustion treatment.The expression level of miR-221 was suppressed by moxibustion treatment.Furthermore,SOCS3 was found as the direct target of miR-221,which mediated the function of moxibustion by regulating the Treg/Th17 cell balance.Conclusion Moxibustion therapy regulated the Treg/Th17 cell balance by modulating the miR-221/SOCS3 axis in the RA mouse model.

Acute and persisting Th2-like immune response after fractionated colorectal γ-irradiation

AIM： To investigate if an immune imbalance may account for the development and progression of chronic radiation enteritis. We analyzed the Th1/Th2 immune response profile early and 6 mo after fractionated colorectal irradiation. METHODS： A rat model of fractionated colorectal γ-irradiation （4-Gy fractions, 3 fractions per week） was designed to investigate the effects of cumulative dose on inflammatory mediators （cytokines and chemo- kines） and immune response （Th1/Th2 profile and immunosuppressive mediator IL-10） during acute （early） response and 6 mo after the end of fractionated irradiation （chronic response）. Analyses were performed 1 d after the cumulative doses of 16 Gy and 36 Gy and 1 d, 3 d, and 26 wk after the cumulative dose of 52 Gy. RESULTS： Without causing histological damage, fractionated radiation induced elevated expression of IL-1β, TNFα, MCP-1, and iNOS in distal colonic mucosa during the early post-irradiation phase. At that time, a Th2 profile was confirmed by expression of both the Th2- specific transcription factor GATA-3 and the chemokine receptor CCR4 and by suppression of the Thl cytokine IFNγ/IP-10 throughout the irradiation protocol. After 6 mo, despite the 2-fold reduction of iNOS and MCP-1 levels, the Th2 profile persisted, as shown by a 50% reduction in the expression of the Thl transcription factor T-bet, the chemokine receptor CCXCR3, and the IFNγ/ STAT1 pathway. At the same time-point, the immunosuppressive IL-10/STAT3 pathway, known to regulate the Th1/Th2 balance, was expressed, in irradiated rats, at approximately half its level as compared to controls.This suppression was associated with an overexpression of SOCS3, which inhibits the feedback of the Thl polarization and regulates IL-10 production. CONCLUSION： Colorectal irradiation induces Th2 polarization, defective IL-10/STAT3 pathway activation and SOCS3 overexpression. These changes, in turn, maintain a immunological imbalance that persists in the long term.

Exendin-4 inhibits high-altitude cerebral edema by protecting against neurobiological dysfunction

The anti-inflammatory and antioxidant effects of exendin-4（Ex-4） have been reported previously.However,whether（Ex-4） has anti-inflammatory and antioxidant effects on high-altitude cerebral edema（HACE） remains poorly understood.In this study,two rat models of HACE were established by placing rats in a hypoxic environment with a simulated altitude of either 6000-or 7000-m above sea level（MASL） for 72 hours.An altitude of 7000 MASL with 72-hours of hypoxia was found to be the optimized experimental paradigm for establishing HACE models.Then,in rats where a model of HACE was established by introducing them to a 7000 MASL environment with 72-hours of hypoxia treatment,2,10 and,100 μg of Ex-4 was intraperitoneally administrated.The open field test and tail suspension test were used to test animal behavior.Routine methods were used to detect change in inflammatory cells.Hematoxylin-eosin staining was performed to determine pathological changes to brain tissue.Wet/dry weight ratios were used to measure brain water content.Evans blue leakage was used to determine blood-brain barrier integrity.Enzyme-linked immunosorbent assay（ELISA） was performed to measure markers of inflammation and oxidative stress including superoxide dismutase,glutathione,and malonaldehyde values,as well as interleukin-6,tumor necrosis factor-alpha,cyclic adenosine monophosphate levels in the brain tissue.Western blot analysis was performed to determine the levels of occludin,ZO-1,SOCS-3,vascular endothelial growth factor,EPAC1,nuclear factor-kappa B,and aquaporin-4.Our results demonstrate that Ex-4 preconditioning decreased brain water content,inhibited inflammation and oxidative stress,alleviated brain tissue injury,maintain blood-brain barrier integrity,and effectively improved motor function in rat models of HACE.These findings suggest that Ex-4 exhibits therapeutic potential in the treatment of HACE.