Metformin Modulates T Cell Function and Alleviates Liver Injury Through Bioenergetic Regulation in Viral Hepatitis.

Metformin is not only the first-line medication for the treatment of type 2 diabetes, but it is also effective as an anti-inflammatory, anti-oxidative and anti-tumor agent. However, the effect of metformin during viral hepatitis remains elusive. Using an adenovirus (Ad)-induced viral hepatitis mouse model, we found that metformin treatment significantly attenuated liver injury, with reduced serum aspartate transaminase (AST) and alanine transaminase (ALT) levels and liver histological changes, presumably via decreased effector T cell responses. We then demonstrated that metformin reduced mTORC1 activity in T cells from infected mice, as evidenced by decreased phosphorylation of ribosome protein S6 (p-S6). The inhibitory effects on the mTORC1 signaling by metformin was dependent on the tuberous sclerosis complex 1 (TSC1). Mechanistically, metformin treatment modulated the phosphorylation of dynamin-related protein 1 (Drp-1) and mitochondrial fission 1 protein (FIS1), resulting in increased mass in effector T cells. Moreover, metformin treatment promoted mitochondrial superoxide production, which can inhibit excessive T cell activation in viral hepatitis. Together, our results revealed a protective role and therapeutic potential of metformin against liver injury in acute viral hepatitis via modulating effector T cell activation via regulating the mTORC1 pathway and mitochondrial functions.

miR-196b-5p controls adipocyte differentiation and lipogenesis through regulating mTORC1 and TGF-ß signaling.

MicroRNAs have been reported to play a role in adipogenesis and obesity. This study was performed to investigate the role of miR-196b-5p in adipogenesis and the mechanism involved. The data revealed that miR-196b-5p expression increased in primary or established marrow stromal progenitor cells after adipogenic treatment. Supplementing miR-196b-5p in the progenitor cells stimulated adipogenic differentiation and lipogenesis, along with the induction of adipogenic and lipogenic factors. Conversely, inhibition of endogenous miR-196b-5p blocked adipogenesis and lipogenesis. Tuberous sclerosis 1 (Tsc1) and transforming growth factor-ß receptor 1 (TGFBR1) were demonstrated to be the direct target genes of miR-196b-5p. Supplementing miR-196b-5p activity in progenitor cells reduced the protein level of TSC1 and activated mammalian target of rapamycin complex 1 (mTORC1) signaling. We further demonstrated that the perturbation of TSC1 in progenitor cells altered the trend of adipogenic differentiation and lipogenesis. Overexpression of Tsc1 or inactivation of mTORC1 signaling attenuated the stimulation of adipogenic differentiation and lipogenesis by miR-196b-5p. Overexpression of Tgfbr1 also partially blocked the adipogenic effect of miR-196b-5p. Further investigations demonstrated that zinc finger E-box-binding homeobox 1 (ZEB1) transcriptionally upregulated miR-196b-5p expression. The current study suggests that miR-196b-5p promotes adipogenic differentiation and lipogenesis in progenitor cells through targeting TSC1 and TGFBR1 and therefore regulating mTORC1 and TGF-ß signaling.

Methylation of Hypothalamic Tsc1-mTOR Signaling in Regulation of Obesity and Obesity Resistance.

The Tsc1-mTOR signaling pathway is often related to obesity, and epigenetic modification may lead to expression changes of obesity-related gene. Therefore, we aim to investigate the methylation of the Tsc1-mTOR signaling pathway in regulation of obesity susceptibility. Wistar rats were fed a normal diet or a high-fat diet to develop animal models. Protein and mRNA expression levels of Tsc1-mTOR signaling in the hypothalamus were determined by Western blot and quantitative real-time PCR. Methylation of Tsc1 gene promoter was detected by bisulfite genomic sequence. Both mRNA and protein expression levels of Tsc1 in DIO group hypothalamus were lower; mTOR and its downstream targets S6K1, 4EBP1, and S6 protein expression levels were higher than those of the DIO-R group and the chow group. The Tsc1 gene promoter methylation rate in the hypothalamus was 92.05 ± 3.07% in the DIO group, 87.27 ± 1.91% in the DIO-R group, and 88.18% ± 3.20% in the chow group, respectively, with significantly higher levels in the DIO group. Both the expression levels of Tsc1 gene promoter methylation and Tsc1-mTOR signaling pathway in the hypothalamus of DIO rats and DIO-R rats are different. These findings may shed light on the potential mechanism for the differentiation of obesity susceptibility.

Weipiling ameliorates gastric precancerous lesions in Atp4a-/- mice.

BACKGROUND: Altered cellular metabolism is considered to be one of the hallmarks of cancer (Coller, Am J Pathol 184:4-17, 2014; Kim and Bae, Curr Opin Hematol 25:52-59, 2018). However, few studies have investigated the role of metabolism in the development of gastric precancerous lesions (GPLs). Weipiling (WPL), a traditional Chinese medicine formula for treatment of GPLs. In this study, we evaluated the amelioration of GPLs by WPL and investigated the possible role of WPL in regulating glucose metabolism. METHODS: Firstly, the major components of WPL are chemically characterized by HPLC analytical method. In this study, we chose the Atp4a-/- mouse model (Spicer etal., J Biol Chem 275:21555-21565, 2000) for GPL analysis. Different doses of WPL were administered orally to mice for 10 weeks. Next, the pathological changes of gastric mucosa were assessed by the H&E staining and AB-PAS staining. In addition, TUNEL staining was used to evaluate apoptosis, and we further used immunohistochemically labelled CDX2, MUC2, ki-67, PTEN, and p53 proteins to assess the characteristic changes of gastric mucosa in precancerous lesions. The levels of such transporters as HK-II, PKM2, ENO1, MPC1, and LDHA were determined by Western blot analysis. Finally, we assessed the expression of mTOR, HIF-1α, AMPK, Rheb, TSC1 and TSC2 protein in the gastric mucosa of Atp4a-/-mice. RESULTS: In this work, we evaluated the protective effect of WPL on gastric mucosa in mice with precancerous lesions. The aberrant apoptosis in gastric mucosa of gastric pre-cancerous lesions was controlled by WPL (P<0.05). Furthermore, WPL suppressed the expression of CDX2, MUC2, ki-67, PTEN and p53, as the levels of these proteins decreased significantly compared with the model group (P<0.05). In parallel, WPL significantly suppressed the expression of transporters, such as HK-II, PKM2, ENO1, MPC1 and LDHA (P<0.05). In addition, mTOR, HIF-1a, AMPK, Rheb, TSC1 and TSC2 protein levels in gastric mucosa of Atp4a-/- mice in the high- and low-dose WPL groups were significantly lower than those in the model group (P<0.05), while the expression of TSC1 and TSC2 protein was significantly higher (P<0.05). CONCLUSIONS: Conclusively, WPL could ameliorate GPLs in Atp4a-/- mice by inhibiting the expression of transporters and suppressing the aberrant activation of mTOR/HIF-1α.

[Mechanism of Electropuncture for Reducing Diet-induced Obesity Rat Weight through Hypothala- mus TSC1 -mTOR Signal Pathway].

OBJECTIVE: To explore the mechanism of electropuncture (EA) for reducing diet-induced obesity (DIO) rat weight through tuberous sclerosis complex 1 (TSC1 )-mammalian target of rapa- mycin (mTOR) signal pathway in hypothalamus. METHODS: Forty male SD rats were randomly divided into the model group (n =30) and the normal control group (n =10). DIO rat model was prepared by high fat forage for 12 successive weeks. Successfully modeled 19 rats were further randomly divided into the model group (n =9) and the EA group (n =10). EA at Tianshu (ST25) , Sanyinjiao (SP6) , Zhongwan ( RN12) , Zusanli (ST36) was performed in the EA group, 5 successive days per week with a 2-day rest, 4 weeks in total. No intervention was given to rats in the model group and the normal control group. Body weight was observed in all rats. Methylation of TSC1 promotor was detected by bisulfite sequencing method. mRNA expression of mTOR in hypothalamus was detected by RT-PCR. RESULTS: After EA treatment body weight in the EA group were obviously reduced (P <0. 05). Compared with the normal control group, body weight was not statistically different between the model group and the EA group after treatment (P> 0. 05). Methylation rate of TSC1 promotor was higher in model group (94. 0% ±4. 5%) than in the normal control group (87. 0% ±3. 6%) and the EA group (87. 4% ±3. 9%) (P <0. 05). Expression of mTOR in the model group (1. 84 ±0. 51) was higher than that in the normal control group (1. 02 ±0. 22) and the EA group (1. 46 ±0. 29) (P <0. 05). CONCLUSION: EA could lower DIO rats' body weight by down-regulating methylation rate of TSC1 promotor and regulating expression of mTOR in hypothalamus.