Follistatin N terminus differentially regulates muscle size and fat in vivo

Delivery of follistatin (FST) represents a promising strategy for both muscular dystrophies and diabetes, as FST is a robust antagonist of myostatin and activin, which are critical regulators of skeletal muscle and adipose tissues. FST is a multi-domain protein, and deciphering the function of different domains will facilitate novel designs for FST-based therapy. Our study aims to investigate the role of the N-terminal domain (ND) of FST in regulating muscle and fat mass in vivo. Different FST constructs were created and packaged into the adeno-associated viral vector (AAV). Overexpression of wild-type FST in normal mice greatly increased muscle mass while decreasing fat accumulation, whereas overexpression of an N terminus mutant or N terminus-deleted FST had no effect on muscle mass but moderately decreased fat mass. In contrast, FST-I-I containing the complete N terminus and double domain I without domain II and III had no effect on fat but increased skeletal muscle mass. The effects of different constructs on differentiated C2C12 myotubes were consistent with the in vivo finding. We hypothesized that ND was critical for myostatin blockade, mediating the increase in muscle mass, and was less pivotal for activin binding, which accounts for the decrease in the fat tissue. An in vitro TGF-beta1-responsive reporter assay revealed that FST-I-I and N terminus-mutated or -deleted FST showed differential responses to blockade of activin and myostatin. Our study provided direct in vivo evidence for a role of the ND of FST, shedding light on future potential molecular designs for FST-based gene therapy.

Effects and mechanism of sophocarpine in rats with alcoholic liver disease / 中华消化杂志

Objective To investigate the efficacy of sophocarpine in rats with alcoholic liver disease and its effects on the expression of tumor necrosis factor (TNF)-α,interleukin (IL)-6 and transforming growth factor (TGF)-β1.Methods A total of 48 male Sprague-Dawley adult rats were evenly divided into healthy control group,model group,prevention group and treatment group.The rats in the healthy control group were gavaged with 0.9％NaCl every day for 12 weeks.The rats in the model group,prevention group and treatment group were gavaged with alcohol for 12 weeks to establish the model.The prevention group was injected with 20 mg · kg1 · d1 sophocarpine for 12 weeks.Since the fifth week,the treatment group was continuously injected with 20 mg · kg1 · d-1 sophocarpine for eight weeks.The histological changes were evaluated.The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase ( AST ), alkaline phosphatase (AKP),triglyceride (TG) and total cholesterol (TC) were examined.And the expression of TNF-α,IL-6 and TGF-β1 in liver tissue at mRNA and protein level were detected with immunohistochemistry and real-time polymerase chain reaction (PCR) assay.Comparison among groups was perform with single factor analysis of variance,pairwise comparisons with least significant difference method (LSD method),ranked data with Kruskal-Wallis H-test and multiple pairwise comparison with Nemenyi test.Results Compared with model group,hepatic steatosis and inflammatory cell infiltration were significantly improved in the treatment group and prevention group.The levels of ALT (41.40 U/L± 10.53 U/L and 40.75 U/L±6.94 U/L vs 58.37 U/I±5.35 U/L),AST(121.60 U/L±16.24 U/L and 109.50 U/L±9.23 U/L vs 156.63 U/L±32.47 U/L),AKP(114.88 U/L±40.37 U/L and 112.60 U/L±44.34 U/L vs 161.75 U/L±28.95 U/L),TG (4.19 mmol/L±0.99 mmol/L and 2.69 mmol/L± 1.35 mmol/L vs 4.50 mmol/L±0.99 mmol/L) and TC (1.48 mmol/L±0.28 mmol/L and 1.43 mmol/L±0.19 mmol/L vs 1.67 mmol/L±0.20 mmol/L) significantly decreased and the difference was statistically significant ( all P＜0.05).The expression of TNF-α,IL-6 and TGF-β1 at mRNA and protein level in liver tissue of model group were significantly higher than those of healthy control group,prevention group and treatment group.After treated with sophocarpine,the expression of TNF-α(mRNA:1.36 ± 0.08,1.16 ± 0.05 ; protein:3.38 ％ ± 0.82 ％,1.74 ％ ± 0.65 ％ ),IL-6 (mRNA:1.51 ± 0.05,1.39 ± 0.02; protein:5.89％ ± 0.96％,4.26％ ± 0.53％) and TGF-β1 (mRNA:1.39±0.04,1.37±0.02; protein:4.27％ ±0.97％,2.11％ ±0.83％) of treatment group and prevention group at mRNA and protein level significantly lower than those of model group (mRNA:1.81±0.16,1.95 ±0.13,1.84±0.22; protein:5.82％ ± 1.21％,7.63％ ±1.03％,5.33％± 1.12％) and the difference was statistically significant (all P＜0.01).Conclusion Sophocarpine significantly alleviates alcohol induced liver injury in rats,improves liver steatosis and inflammatory reaction degree,which may be related with the downregulation of TNF-α,TGF-β1 and IL-6 expression in liver tissue of ALD rats.