Coordinated Regulation of Myelination by Growth Factor and Amino-acid Signaling Pathways / 神经科学通报·英文版

Myelin-forming oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS) are essential for structural and functional homeostasis of nervous tissue. Albeit with certain similarities, the regulation of CNS and PNS myelination is executed differently. Recent advances highlight the coordinated regulation of oligodendrocyte myelination by amino-acid sensing and growth factor signaling pathways. In this review, we discuss novel insights into the understanding of differential regulation of oligodendrocyte and Schwann cell biology in CNS and PNS myelination, with particular focus on the roles of growth factor-stimulated RHEB-mTORC1 and GATOR2-mediated amino-acid sensing/signaling pathways. We also discuss recent progress on the metabolic regulation of oligodendrocytes and Schwann cells and the impact of their dysfunction on neuronal function and disease.

Experimental study of curcumol inhibiting vascular endothelial growth factor-induced neovascularization / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the role and mechanism of curcumol in neovascularization induced by vascular endothelial growth factor(VEGF).METHODS: Human umbilical vein endothelial cells were cultured in vitro and treated with 50ng/mL VEGF and curcumol at different concentrations. Cell proliferation was detected by CCK-8 and EdU assay, the migration ability of cells was analyzed by Transwell assay, the angiogenesis ability of endothelial cells was analyzed by tube formation assay, and the change of Akt/mTORC1 signal pathway was detected by Western blot.RESULTS: CCK-8 results showed that the OD450 value of cells in 400 and 800 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(all P<0.01). EdU results showed that the rate of cell proliferation in 400 μmol/L curcumol+VEGF group was significantly lower than that in VEGF group(P<0.001). Transwell assay and the formation assay results showed that the number of migratory cells in 400 μmol/L curcumol+VEGF group was decreased, and the number and length of tube branches were also reduced compared with VEGF group(all P<0.001). Western blot results showed that curcumol significantly inhibited the expression of p-Akt and p-S6, which were downstream targets of Akt/mTORC1 pathway in cells.CONCLUSION: Curcumol can inhibit VEGF-induced cell proliferation, migration and tube formation of vein endothelial cells, and has a strong inhibitory effect on angiogenesis, which can be further studied in the treatment of ocular fundus neovascularization.

Methyltransferase-like 3 affects glycolysis and proliferation of esophageal squamous cell carcinoma cells by regulating the GLUT4-mTORC1 axis / 中国肿瘤生物治疗杂志

@#[摘 要] 目的：探讨甲基转移酶样因子3（METTL3）在食管鳞状细胞癌（ESCC）组织和细胞中的表达水平及其对ESCC细胞糖酵解和增殖能力的影响和潜在的分子机制。方法：基于TCGA数据库分析METTL3在ESCC细胞中的表达及可能的富集通路。收集2021年1月至2021年6月间在北川医学院附属医院外科手术切除的34例ESCC组织及相应癌旁组织，采用免疫组化法验证ESCC组织中METTL3的表达。采用CCK-8法和平板克隆形成实验检测干扰METTL3后ESCC细胞增殖能力的变化，利用比色法检测干扰METTL3后ESCC细胞总RNA中m6A的表达水平，采用甲基化RNA免疫沉淀定量PCR（MeRIP-qPCR）检测METTL3对葡萄糖转运蛋白4（GLUT4）基因mRNA的m6A修饰水平的影响，采用WB和qPCR等技术探索METTL3参与ESCC细胞糖酵解的生物学机制。结果：METTL3在ESCC组织以及细胞中均呈高表达（均P<0.001）。干扰METTL3表达后，ESCC细胞的增殖能力明显减弱、细胞内总RNA的m6A修饰水平显著降低（均P<0.001）。此外，干扰METTL3可显著抑制KYSE150和TE-1细胞中GLUT4基因mRNA的m6A修饰水平（均P<0.01），并通过下调GLUT4的表达抑制葡萄糖的摄取以及乳酸的释放（均P<0.01），最终下调mTORC1通路活性并抑制ESCC细胞的增殖；在干扰METTL3的ESCC细胞同时联合运用mTORC1通路抑制剂显示有协同的抗癌作用。结论：METTL3介导的m6A修饰通过调控GLUT4-mTORC1信号轴影响ESCC细胞的糖酵解及增殖。

Intervention Mechanism of Xiaoluowan on Experimental Goiter Rats Based on PI3K/Akt/mTORC1 Pathway / 中国实验方剂学杂志

ObjectiveBy observing the effect of Xiaoluowan on phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin complex 1 （mTORC1） pathway in experimental goiter rats， this study aims to explore its therapeutic effect on experimental goiter rats. MethodSixty 5-month-old SD rats of SPF grade were purchased， half males and half females， of which 10 were used as a normal group， and the remaining rats were administrated with propylthiouracil （PTU） solution to induce nodular goiter. After successful modeling， rats were randomly divided into a model group， levothyroxine sodium tablets group， Xiaoluowan low-dose group， medium-dose group， and high-dose group， ten rats each. The levothyroxine sodium tablets group was given 15 μg·kg-1 levothyroxine sodium tablets by gavage. The Xiaoluowan low-， medium-， and high-dose groups were given （ig） Xiaoluowan low-dose （10 g·kg-1）， medium-dose （20 g·kg-1）， and high-dose （30 g·kg-1） Xiaoluowan， and the normal group and model group were administered （ig） with the same volume of 0.9% sodium chloride solution. Four weeks after the intervention， rats were sacrificed by routine intraperitoneal anesthesia using 5% phenobarbital. Subsequently， the histopathology was observed under a microscope， and serum thyroid hormone levels were measured using a Roche electrochemiluminescence immunoassay analyzer. Serum cytokines were detected by enzyme-linked immunosorbent assay （ELISA）， and neurotransmitters were measured using a high-performance liquid chromatograph. The protein level of PI3K/Akt/mTORC1 pathway was determined by Western blot. ResultAs compared with the normal group， the levels of basic fibroblast growth factor （bFGF）， vascular endothelial growth factor （VEGF）， insulin-like growth factor （IGF-1）， 5-hydroxytryptamine （5-HT）， and thyroid stimulating hormone （TSH） were increased， and PI3K， Akt， and mTORC1 protein levels were up-regulated in the model group， while the levels of norepinephrine （NE）， triiodothyronine （T3）， tetraiodothyronine （T4）， free triiodothyronine （FT3）， and free thyroid hormone （FT4） were decreased （P<0.05）. Compared with the model group， the levothyroxine sodium tablets group， and Xiaoluowan low-， medium-， and high-dose groups exhibited reduced levels of bFGF， VEGF， IGF-1， 5-HT， and TSH， and down-regulated PI3K， Akt， and mTORC1 protein levels， and increased NE， T3， T4， FT3， and FT4 levels （P<0.05）. ConclusionXiaoluowan may act on the PI3K/Akt/mTORC1 signaling pathway to play its role in the treatment of nodular goiter， and it is dose-dependent.

Nuciferine protects against high-fat diet-induced hepatic steatosis and insulin resistance via activating TFEB-mediated autophagy-lysosomal pathway

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis and insulin resistance and there are currently no approved drugs for its treatment. Hyperactivation of mTOR complex 1 (mTORC1) and subsequent impairment of the transcription factor EB (TFEB)-mediated autophagy-lysosomal pathway (ALP) are implicated in the development of NAFLD. Accordingly, agents that augment hepatic TFEB transcriptional activity may have therapeutic potential against NAFLD. The objective of this study was to investigate the effects of nuciferine, a major active component from lotus leaf, on NAFLD and its underlying mechanism of action. Here we show that nuciferine activated ALP and alleviated steatosis, insulin resistance in the livers of NAFLD mice and palmitic acid-challenged hepatocytes in a TFEB-dependent manner. Mechanistic investigation revealed that nuciferine interacts with the Ragulator subunit hepatitis B X-interacting protein and impairs the interaction of the Ragulator complex with Rag GTPases, thereby suppressing lysosomal localization and activity of mTORC1, which activates TFEB-mediated ALP and further ameliorates hepatic steatosis and insulin resistance. Our present results indicate that nuciferine may be a potential agent for treating NAFLD and that regulation of the mTORC1-TFEB-ALP axis could represent a novel pharmacological strategy to combat NAFLD.

Analysis on Role of mTORC1/4E-BP1 Axis in Idiopathic Pulmonary Fibrosis and Research Progress of Bupleuri Radix on Its Intervention / 中国实验方剂学杂志

Idiopathic pulmonary fibrosis （IPF） is a common， lethal interstitial lung disease characterized by airway remodeling， inflammation， alveolar destruction， and fibrosis. The mammalian target of rapamycin complex 1/4E binding protein 1 （mTORC1/4E-BP1） axis is closely related to the expression of collagen by fibroblasts， and its role in pulmonary fibrosis remains to be further elucidated. Traditional Chinese medicine （TCM） has shown promising efficacy in improving the lung function， exercise capacity， and quality of life in patients with IPF. The theory of "same treatment for different diseases" provides a TCM theoretical basis for the treatment of pulmonary fibrosis with Bupleuri Radix， while the research in western medicine has preliminarily shown that both the formulation and single herb as well as the active ingredients of Bupleuri Radix have good therapeutic effects on pulmonary fibrosis. Therefore， this review will elaborate on the role of the mTORC1/4E-BP1 axis in the pathomechanism of IPF， as well as the research results of the active components of Bupleuri Radix on the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin protein（PI3K/AKT/mTOR） pathway， so as to provide a reference for the treatment and drug development of IPF.

8-Azaguanine-induced autophagy contributes to its chemoresistance in hepatic cancer cells / 药学学报

Autophagy, an evolutionarily conserved process by which components of the cell are degraded in lysosomes, may facilitate survival of cancer cells under stress conditions. 8-Azaguanine (8-AG), an inhibitor of purine nucleotide biosynthesis, shows antineoplastic activity in multiple tumor cells. However, chemoresistance has restricted its development as an anticancer agent, and the mechanism of 8-AG resistance is not fully understood. We report here that 8-AG induces a protective autophagy to eliminate its cytotoxicity, and inhibition of autophagy increases cellular sensitivity of cancer cells to 8-AG treatment. Using HepG2 or SMMC-7721 hepatic cancer cell lines, we found that 8-AG inhibited cell viability and induced intrinsic apoptosis, accompanied by the up-regulation of the pro-apoptotic protein BimS, one of Bim (also known as BCL-2-like protein 11, BCL2L11) isoforms. Furthermore, 8-AG treatment enhanced the autophagy flux by promoting the dephosphorylation and activation of Unc-51-like autophagy activating kinase 1 (ULK1) via Akt/mTORC1 (mammalian target of rapamycin complex 1) signaling inhibition. Depletion of autophagy-related gene 7 (ATG7) markedly enhanced the level of BimS, and promoted cell death in response to 8-AG. 8-AG in combination with autophagy inhibitor chloroquine (CQ) or bafilomycin A1 (Baf A1) promoted the 8-AG-induced apoptosis in hepatic cancer cells. Altogether, these findings suggest that autophagy promotes chemoresistance of cancer cells for 8-AG, and blocking autophagy increases cellular sensitivity of cancer cells to 8-AG treatment.

KIF2C: a novel link between Wnt/β-catenin and mTORC1 signaling in the pathogenesis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and is the fourth-leading cause of cancer-related deaths worldwide. HCC is refractory to many standard cancer treatments and the prognosis is often poor, highlighting a pressing need to identify biomarkers of aggressiveness and potential targets for future treatments. Kinesin family member 2C (KIF2C) is reported to be highly expressed in several human tumors. Nevertheless, the molecular mechanisms underlying the role of KIF2C in tumor development and progression have not been investigated. In this study, we found that KIF2C expression was significantly upregulated in HCC, and that KIF2C up-regulation was associated with a poor prognosis. Utilizing both gain and loss of function assays, we showed that KIF2C promoted HCC cell proliferation, migration, invasion, and metastasis both in vitro and in vivo. Mechanistically, we identified TBC1D7 as a binding partner of KIF2C, and this interaction disrupts the formation of the TSC complex, resulting in the enhancement of mammalian target of rapamycin complex1 (mTORC1) signal transduction. Additionally, we found that KIF2C is a direct target of the Wnt/β-catenin pathway, and acts as a key factor in mediating the crosstalk between Wnt/β-catenin and mTORC1 signaling. Thus, the results of our study establish a link between Wnt/β-catenin and mTORC1 signaling, which highlights the potential of KIF2C as a therapeutic target for the treatment of HCC.

Discovery of a small molecule inhibitor of cullin neddylation that triggers ER stress to induce autophagy

Protein neddylation is catalyzed by a three-enzyme cascade, namely an E1 NEDD8-activating enzyme (NAE), one of two E2 NEDD8 conjugation enzymes and one of several E3 NEDD8 ligases. The physiological substrates of neddylation are the family members of cullin, the scaffold component of cullin RING ligases (CRLs). Currently, a potent E1 inhibitor, MLN4924, also known as pevonedistat, is in several clinical trials for anti-cancer therapy. Here we report the discovery, through virtual screening and structural modifications, of a small molecule compound HA-1141 that directly binds to NAE in both

Pharmacological inhibition of mTORC1 activity protects against inflammation-induced apoptosis of nucleus pulposus cells

Lumbar disc herniation is a common disease characterized by the degeneration of intervertebral discs (IVDs), accompanied by imbalance of metabolic and inflammatory homeostasis. Current studies establish that IVD degeneration is induced by increased apoptosis of nucleus pulposus (NP) cells. However, the underlying mechanisms of NP cell survival/apoptosis are not well elucidated. Here, we reveal a novel mechanism by which mTORC1 signaling controls NP cell survival through regulating metabolic homeostasis. We demonstrated that hyperactivated mTORC1 activity induced by inflammatory cytokines engenders the apoptosis of NP cells, whereas pharmacological inhibition of mTORC1 activity promotes NP cell survival. Using an integrative approach spanning metabolomics and biochemical approaches, we showed that mTORC1 activation enhanced glucose metabolism and lactic acid production, and therefore caused NP cell apoptosis. Our study identified mTORC1 in NP cells as a novel target for IVD degeneration, and provided potential strategies for clinical intervention of lumbar disc herniation.

Effect of mTORC1 on intestinal group 3 innate lymphocytes function / 上海交通大学学报（医学版）

Objective : To investigate the effect of mechanistic target of rapamycin complex 1 (mTORC1) on group 3 innate lymphoid cells (ILC3) function. Methods ¡¤ Intestinal lamina propria leukocytes (LPL) of C57BL/6 wild type mice were stimulated by rapamycin, the specific inhibitor of mTORC1 signaling pathway, in vitro, and then quantity and function of ILC3 were detected by flow cytometry. Next, purified ILC3 from mice intestinal LPL were sorted by flow cytometry. After the activation of ILC3 with IL-23, mRNA expression levels of Rorc (the gene encoding retinoic acid receptor related orphan receptor, i.e. RORγt), Il22 and Rptor (the gene encoding key component protein of mTORC1, i.e. Raptor) were detected by real-time qPCR. For further study, a genetically engineered mouse model specifically knocked out Raptor in ILC3 was constructed. Effects of mTORC1 loss on the quantity and function of ILC3 as well as gut structure were detected by flow cytometry, real-time qPCR and hematoxylin-eosin staining. Results ¡¤ The total ILC3 number had no change, but the secretion of IL-22 by ILC3 reduced after stim-ulation with rapamycin. Il22, Rorc and Rptor mRNA expression levels were upregulated simultaneously in ILC3 after activation with IL-23. In addition, there was no significant difference in the numbers and proportions of total ILC3 and ILC3 subsets as well as gut structure in Rap-tor-deficient mice, but the cytokine IL-22 secretion level of ILC3 significantly decreased in these mice. Conclusion ¡¤ Loss of mTORC1 func-tion inhibits ILC3 from secreting IL-22 but has no effect on the intestinal structure and intestinal ILC3 development, which reveals the positive regulation of mTORC1 signaling on intestinal ILC3 function.

Mechanisms of rapamycin on regulating rat mesangial cell proliferation and cell cycle through mTORC1/p70S6K pathways / 药学学报

To explore the affect and mechanisms of rapamycin on mesangial cell proliferation and cell cycle, rat mesangial cells (HBZY-1) were cultured and divided into the six groups: normal; normal with platelet derived growth factor (PDGF) 20 ng·mL-1; PDGF + rapamycin 1, 10, 100, 1 000 nmol·L-1. The cell proliferation was measured by MTT in 24 and 48 h; flow cytometry was used to detect the cell cycle phase. Western blot was performed to determine cyclin D1,cyclin E, cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), p27, p70S6K/p-p70S6K protein expression. The p27 mRNA was detect by Real-time PCR. The results showed that rapamycin significantly suppressed PDGF induced glomerular mesangial cells (MCs) proliferation in a dose and time-dependent manner, but with the dose increased (1 to 1 000 nmol·L-1), the time dependence gradually weakened. Rapamycin inhibited mesangial cell proliferation and arrested the cell cycle in the G0/G1 phase. PDGF at 20 ng·mL-1 significantly increased the expression of cyclin D1, cyclin E and CDK2, CDK4 (P < 0.05), but rapamycin did not affect the expression of cyclin D1, cyclin E and CDK2, CDK4. Rapamycin can significantly inhibited p70S6K phosphorylation, up-regulated the expression of p27 protein and mRNA. Collectively, rapamycin has the effect of inhibiting the glomerular mesangial cells proliferation of mesangial cells by regulating the transcription of p27 mRNA, increasing its protein expression through the mTORC1/p70S6K pathway, resulting in decreased activity of cyclin-CDK, and blocking cell cycle in G0/G1 phase.

Study on lipid-lowering mechanism of active peptide DP17 from Eupolyphaga steleophaga in hyperlipidemia rats / 中国中药杂志

The aim of this paper was to investigate the mechanism of the active peptide DP17 of Eupolyphaga steleophaga in the treatment of hyperlipidemia rats. HPLC and MADIL-TOF/TOF-MS were used for the amino acid sequence analysis and solid-phase synthesis on the active peptide of E. steleophaga which were obtained by biomimetic enzymatic hydrolysis, separation and purification. The hyperlipidemia model was established by feeding with high-fat diet.Twenty days later, the rats in the blank group and the model group were given the saline and the rats in remaining groups were given the corresponding drugs by oral administration. After administration for 4 weeks, the levels of triglyceride(TG), total cholesterol(TC) and low density lipoprotein(LDL) in serum, the levels of TG, TC, adenosine monophosphate(AMP), adenosine triphosphate(ATP) in liver tissues and TG in feces were detected, respectively. Hematoxylin-eosin(HE) staining was used to observe the pathological changes of liver tissues. The Real-time fluorescence quantitative PCR method was used to detect the expression of acetyl coa carboxylase(ACC) and hydroxymethylglutaryl-coa reductase(HMGCR) mRNA in liver tissues. The expression of mammalian target of rapamycin(mTORC1) protein and adenosine 5'-monophosphate-activated protein kinase(AMPK) in liver tissues were detected by Western blot. The analysis showed that the amino acid sequence of active peptide from E. steleophaga was DAVPGAGPAGCHPGAGP(DP17). The results of pharmacological experiments showed that after oral administration of DP17 in rats, the levels of TG, TC and LDL in serum as well as TG and TC levels in liver tissues were significantly decreased(P<0.05), while the levels of AMP, ATP in liver tissues and TG content in feces were significantly increased(P<0.05); the liver steatosis of rats was significantly relieved; the expression of ACC, HMGCR mRNA and mTORC1 protein in liver tissues were significantly reduced, while the expression of AMPK phosphorylated protein was significantly increased(P<0.05). DP17, the active peptide of E. steleophag can significantly reduce lipid accumulation in liver tissues, and it may play a role in reducing blood lipids by regulating the energy metabolism balance in the body and activating AMPK/mTOR signaling pathway.

Effect of Shenling Baizhusan on mTORC1/STAT3 Pathway in Hepatocytes of Nonalcoholic Fatty Liver Disease Rats / 中国实验方剂学杂志

Objective::To observe the effect of Shenling Baizhusan(SBS)on the mammalian target of rapamycin complex 1 (mTORC1)/signal transducers and activators of transcription 3 (STAT3) pathway in liver hepatocyte of nonalcoholic fatty liver disease(NAFLD)rats induced by high fat diet, in order to reveal the mechanism of SBS against rat NAFLD from the perspective of inflammation. Method::Totally 80 SD rats were randomly divided into 4 groups, normal control group, model group, high-dose SBP group(30 g·kg-1), and low-dose SBS group(10 g·kg-1), with 20 rats in each group. The rats of NAFLD model were established by being fed with high-fat diets for 8 weeks, and the treatment groups were fed with high or low dose of SBS respectively. After treatment for 8 weeks, blood and liver samples of rats were collected. Alanine aminotransferase (ALT), aspartate aminotransferase(AST), total cholesterol (TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels in blood serum were detected with automatic biochemical analyzer. The liver tissues were observed by oil red O and hematoxylin-eosin (HE) staining. Hepatocytes were isolated by type Ⅳ collagenase perfusion in vitro. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-5 and IL-6 in hepatocytes were detected by enzyme-linked immunosorbent assay (ELISA), and the relevant gene and proteins expressions of mTORC1 and STAT3 in hepatocytes were detected by Real-time fluorescent quantitative polymerase chain reaction (Real-time PCR) and Western blot detection respectively. Result::Compared with the normal control group, the serum levels of TG, TC, AST, ALT and LDL-C were increased significantly, the levels of TNF-α, IL-1β, IL-5 and IL-6 in hepatocytes were increased significantly, and the expression levels of mTORC1, STAT3 mRNA and proteins in hepatocytes were increased significantly(P<0.01). Compared with the model group, the hepatic lipid accumulation of the medicine intervention group was relieved significantly, the serum levels of AST, ALT, TG and LDL-C were decreased significantly, the expression levels of TNF-α, IL-1β, IL-5 and IL-6 of hepatocytes were decreased significantly, and the expressions of mTORC1, STAT3 mRNA and proteins in hepatocytes were decreased significantly(P<0.05, P<0.01). In the high-dose SBS group, the effects in improving the lipid accumulation and inhibiting the inflammatory reaction were better than those of the low-dose SBS group, and the expressions of mTORC1 and STAT3 genes and proteins in hepatocytes were significantly decreased (P<0.05, P<0.01). Conclusion::SBS can improve the fat metabolism disorder and reduce liver lipid accumulation and inflammatory reaction in NAFLD rats induced by high-fat diet. The mechanism may be correlated with the inhibition of mTORC1/STAT3 pathway relating to genes and protein expression in hepatocytes.

Mechanistic Target of Rapamycin Pathway in Epileptic Disorders

The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.

mTORC1 signaling specifically promotes proliferation of hair follicle stem cells during the telogen-to-anagen transition / 中华皮肤科杂志

Objective@#To identify the time window during which the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway plays a key role in telogen-to-anagen transition of hair follicles, and to explore whether the pathway specifically promotes the proliferation of hair follicle stem cells (HFSCs) .@*Methods@#Totally, 36 newborn ICR mice were randomly and equally divided into 3 groups: RAPA-P19 group intraperitoneally injected with 5 mg·kg-1·d-1 sirolimus on days 19-24 after birth, RAPA-P21 group intraperitoneally injected with 5 mg·kg-1·d-1 sirolimus on days 21-24 after birth, and control group intraperitoneally injected with the same volume of solvent on days 19-24 after birth. Four mice were sacrificed in each group on days 22, 23 and 24 separately. Skin tissues were resected from the back, and hematoxylin-eosin staining of the skin tissues were performed followed by observation of hair follicle morphology to evaluate whether murine hair follicles progressed into the anagen phase on day 24. Immunofluorescence costaining was conducted to determine the expression and localization of mTORC1 downstream molecular marker pS6 and cell proliferation marker Ki67 on days 22 and 23.@*Results@#On day 24, hematoxylin-eosin staining showed anagen hair follicles in the control group and RAPA-P21 group, but telogen hair follicles in the RAPA-P19 group. On days 22 and 23, immunofluorescence costaining revealed positive staining for both pS6 and Ki67 in HFSCs in the control group, negative staining for both pS6 and Ki67 in the RAPA-P19 group, negative staining for pS6 and positive staining for Ki67 in the RAPA-P21 group. On day 23, epidermal cells and sebaceous gland cells in the upper hair follicle bulge were stained positively for Ki67 in all the 3 groups.@*Conclusion@#mTORC1 signaling specifically promotes the proliferation of HFSCs during telogen-to-anagen transition, but not affects proliferation of other cells in hair follicles.

Regulation of blood-testis barrier dynamics by the mTORC1/rpS6 signaling complex: An in vitro study / 亚洲男科学杂志(英文版)

During spermatogenesis, developing germ cells that lack the cellular ultrastructures of filopodia and lamellipodia generally found in migrating cells, such as macrophages and fibroblasts, rely on Sertoli cells to support their transport across the seminiferous epithelium. These include the transport of preleptotene spermatocytes across the blood-testis barrier (BTB), but also the transport of germ cells, in particular developing haploid spermatids, across the seminiferous epithelium, that is to and away from the tubule lumen, depending on the stages of the epithelial cycle. On the other hand, cell junctions at the Sertoli cell-cell and Sertoli-germ cell interface also undergo rapid remodeling, involving disassembly and reassembly of cell junctions, which, in turn, are supported by actin- and microtubule-based cytoskeletal remodeling. Interestingly, the underlying mechanism(s) and the involving biomolecule(s) that regulate or support cytoskeletal remodeling remain largely unknown. Herein, we used an in vitro model of primary Sertoli cell cultures that mimicked the Sertoli BTB in vivo overexpressed with the ribosomal protein S6 (rpS6, the downstream signaling protein of mammalian target of rapamycin complex 1 [mTORC1]) cloned into the mammalian expression vector pCI-neo, namely, quadruple phosphomimetic and constitutively active mutant of rpS6 (pCI-neo/p-rpS6-MT) versus pCI-neo/rpS6-WT (wild-type) and empty vector (pCI-neo/Ctrl) for studies. These findings provide compelling evidence that the mTORC1/rpS6 signal pathway exerted its effects to promote Sertoli cell BTB remodeling. This was mediated through changes in the organization of actin- and microtubule-based cytoskeletons, involving changes in the distribution and/or spatial expression of actin- and microtubule-regulatory proteins.

Sensors for the mTORC1 pathway regulated by amino acids / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to various environmental inputs, especially amino acids. In fact, the activity of mTORC1 is highly sensitive to changes in amino acid levels. Over past decades, a variety of proteins have been identified as participating in the mTORC1 pathway regulated by amino acids. Classically, the Rag guanosine triphosphatases (GTPases), which reside on the lysosome, transmit amino acid availability to the mTORC1 pathway and recruit mTORC1 to the lysosome upon amino acid sufficiency. Recently, several sensors of leucine, arginine, and S-adenosylmethionine for the amino acid-stimulated mTORC1 pathway have been coming to light. Characterization of these sensors is requisite for understanding how cells adjust amino acid sensing pathways to their different needs. In this review, we summarize recent advances in amino acid sensing mechanisms that regulate mTORC1 activity and highlight these identified sensors that accurately transmit specific amino acid signals to the mTORC1 pathway.

Mechanistic Target of Rapamycin Pathway in Epileptic Disorders

The mechanistic target of rapamycin (mTOR) pathway coordinates the metabolic activity of eukaryotic cells through environmental signals, including nutrients, energy, growth factors, and oxygen. In the nervous system, the mTOR pathway regulates fundamental biological processes associated with neural development and neurodegeneration. Intriguingly, genes that constitute the mTOR pathway have been found to be germline and somatic mutation from patients with various epileptic disorders. Hyperactivation of the mTOR pathway due to said mutations has garnered increasing attention as culprits of these conditions : somatic mutations, in particular, in epileptic foci have recently been identified as a major genetic cause of intractable focal epilepsy, such as focal cortical dysplasia. Meanwhile, epilepsy models with aberrant activation of the mTOR pathway have helped elucidate the role of the mTOR pathway in epileptogenesis, and evidence from epilepsy models of human mutations recapitulating the features of epileptic patients has indicated that mTOR inhibitors may be of use in treating epilepsy associated with mutations in mTOR pathway genes. Here, we review recent advances in the molecular and genetic understanding of mTOR signaling in epileptic disorders. In particular, we focus on the development of and limitations to therapies targeting the mTOR pathway to treat epileptic seizures. We also discuss future perspectives on mTOR inhibition therapies and special diagnostic methods for intractable epilepsies caused by brain somatic mutations.

Mechanism of recombinant human S100 calcium binding protein A4 inducing vascular endothelial growth factors in rheumatoid arthritis fibroblast-like synoviocytes / 中华创伤骨科杂志

Objective To investigate the mechanism of inducing production of vascular endothelial growth factors (VEGF) by recombinant human S100 calcium binding protein A4 (rhS100A4) in rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs).Methods Synovial tissue was sampled from the patients with rheumatoid arthritis (RA) undergoing knee arthroplasty for in vitro culture of RAFLSs.CCK-8 assay was conducted to detect the effect of rhS100A4 and the effect of its interaction with Rapamycin (Rap),an inhibitor of mammalian rapamycin target 1 (mTORC1) signaling pathway,on the proliferation of RAFLSs.The effects of rhS100A4 and its interaction with Rap on the expression of VEGF in RAFLSs were detected by immunofluorescence.After rhS100A4 and its cooperation with Rap stimulated the conditioned medium (CM)produced by RAFLSs,the effect of CM on formation of lumen in human unbilical vein endothelial cells (HUVECs) in vitro was observed to detect the angiogenic ability of rhS100A4.Western blot was used to detect the effect of rhS100A4 on the phosphorylation of downstream ribosomal protein S6 (S6) in the mTORC1 signaling pathway in RAFLSs and to analyze the effects of rhS100A4 and Rap on phosphorylation of S6 protein and expression of VEGF protein in RAFLSs.Results rhS100A4 promoted cell proliferation and expression of VEGF protein in RAFLSs,and the CM formed by rhS100A4 promoted HUVECs to form blood vessels in vitro.Rap inhibited the above biological effects of rhS100A4,rhS100A4 activated the downstream protein S6 in the mTORC1 signaling pathway in RAFLSs cells to increase their phosphorylation levels.The effects of rhS100A4 on the phosphorylation of S6 protein and on the expression of VEGF protein in RAFLSs were inhibited by Rap.Conclusion rhS10OA4 promotes production of VEGF in RAFLSs by activating the mTORC 1 signaling pathway.