Kaempferol promotes osteogenic differentiation of mouse bone marrow mesenchymal cells under tension stress via the mTORC1 signaling pathway / 口腔疾病防治

Objective @#To investigate the activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway molecules during the process by which kaempferol (Kae) promotes osteogenic differentiation of mouse bone marrow mesenchymal cells (BMMCs) under cyclic and uniaxial tension.@*Methods @#BMMCs isolated and cultured in vitro were subjected to uniaxial dynamic tension with a 10% shape variable. The appropriate concentration of Kae was selected by cytotoxicity testing. The endogenous mTOR signal was inhibited by pp242. Four hours after traction, alkaline phosphatase (ALP) and osteocalcin (OCN) were detected by chemical colorimetry and ELISA, and the relative concentration of intracellular calcium was detected by flow cytometry. Phosphorylation of mTOR, 4E/BP1, and ribosomal protein S6 kinases (S6K), which are the main molecules of the endogenous mTORC1 signaling pathway, and expression of osteogenic transcription factors (Runx2 and Osterix) were detected by western blotting (WB), and mRNA expression levels of the above factors were detected by qRT-PCR.@*Results @# The cytotoxicity test showed that 10 μmol/L Kae had little inhibitory effect on cell proliferation but had the strongest osteogenic ability. Four hours after stretching, Kae effectively promoted the osteogenic differentiation of BMMCs. The expression of ALP was （153.04 ± 18.72） U/mg, the expression of OCN was （1.64 ± 0.25） U. The mRNA and protein levels of Runx2 and Osterix were upregulated, and the intracellular calcium content was decreased. The mRNA and protein phosphorylation of mTOR and S6K was upregulated, and the opposite effect was observed with 4E/BP1. After pp242 was added to inhibit mTOR signaling, mTOR and S6K mRNA and protein phosphorylation were downregulated, but 4E/BP1 mRNA and protein phosphorylation was upregulated. The osteogenic differentiation of BMMCs was also significantly inhibited, mRNA and protein expression of Runx2 and Osterix were significantly downregulated, ALP and OCN expression were downregulated, and intracellular calcium content was increased. @* Conclusion@#Kae promotes osteogenic differentiation of mouse BMMCs under uniaxial dynamic tension through the mTORC1 signaling pathway.

Exploring Mechanism of Modified Fuzi Lizhongtang in Intervening Inflammatory Response of Intestinal Mucosa in Rats with Ulcerative Colitis Based on mTOR/p-S6K1 / 中国实验方剂学杂志

Objectives:To investigate the therapeutic effect and mechanism of modified Fuzi Lizhongtang on ulcerative colitis （UC） model rats. Method:The 72 male SD rats were randomly divided into normal group，model group，sulfasalazine group（0.5 g·kg-1），modified Fuzi Lizhongtang high，medium and low-dose group （23.62，11.81，5.91 g·kg-1）. These rats were used to replicate the UC rat model by 2，4，6-trinitrobenzene sulfonic acid （TNBS）-ethanol composite modeling and treated by gavage for 2 weeks. The general condition of rats in each group was observed. After anesthesia，blood was collected from abdominal aorta and colonic tissue was taken. Semi quantitative evaluation by the colon mucosa damage index （CMDI），the pathological changes of colonic tissue were observed by the hematoxylin and eosin （HE） staining. The contents of serum interleukin-4 （IL-4），IL-6，IL-10 and tumor necrosis factor-α （TNF-α） were detected by enzyme-linked immunosorbent assay （ELISA）. The expressions of mammalian target of rapamycin（mTOR） and phosphorylated ribosomal protein S6 kinase 1 （p-S6K1） in colonic mucosa were detected by immunohistochemistry （IHC） and Western blot. Result:Compared with normal group，the CMDI score of the model group rats was significantly increased （P<0.01）. The contents of IL-4 and IL-10 in serum were significantly decreased，the contents of IL-6 and TNF-α were significantly increased （P<0.01）. The expression levels of mTOR and p-S6K1 in colonic mucosa were up-regulated （P<0.01）. Compared with model group，the CMDI score of the modified Fuzi Lizhongtang high dose group was significantly decreased （P<0.05）. In modified Fuzi Lizhongtang high and medium dose group，the contents of IL-6 and TNF-α were significantly decreased （P<0.01） and the contents of IL-4 and IL-10 in serum were significantly increased （P<0.05，P<0.01）. In the modified Fuzi Lizhongtang high dose group，the expression level of mTOR and p-S6K1 protein was down-regulated significantly （P<0.05，P<0.01）. Conclusion:Modified Fuzi Lizhongtang high dose group can significantly reduce the congestion and edema，inflammatory cell infiltration，gland distortion，disorder of arrangement and other pathological manifestations of UC colon mucosa，and its mechanism may be related to its down-regulation of mTOR/p-S6K1 signal and the regulation of inflammatory factors secretion.

The role of the mTORC1 signaling pathway during osteogenic differentiation of mouse bone marrow mesenchymal cells under tension stress / 口腔疾病防治

Objective@# To investigate the expression of the mTORC1 signaling pathway during the osteogenic differentiation of mouse bone marrow mesenchymal cells (BMMSCs) under cyclic uniaxial tension and explore its possible role.@*Methods @# The BMMSCs of mice were affected by uniaxial dynamic tensile force. Western blot was used to detect the expression changes of major molecules (mTOR, Raptor, S6K) in the endogenous mTORC1 signaling pathway at 0, 1, 2, 4, and 8 hours after stretching. Chemical colorimetry, ELISA and PCR were used to detect alkaline phosphatase (ALP), osteocalcin (OCN) and Runx2 mRNA, respectively. Then, inhibition, activation and control groups were established by administration of the drugs PP242, MHY1485 and PBS, respectively. Two hours after the stress, the expression of S6K was detected by western blot, and the expression of the osteogenic signal was continuously detected by the above methods.@*Results @#Western blot analysis showed that the main molecules of the mTORC1 signaling pathway were all expressed within 8 hours after traction, and the highest expression was 2 hours after the stress. Compared with those in the control group, the ALP activity and OCN expression decreased and the Runx2 mRNA levels increased after the mTORC1 signal pathway was inhibited (P ＜ 0.001); ALP activity and OCN expression increased after the mTORC1 signal pathway was activated, while the Runx2 mRNA levels decreased (P ＜ 0.001). @*Conclusion @#The mTORC1 signaling pathway participates in the osteogenic differentiation of mouse BMMSCs under tension. The osteogenesis of BMMSCs under cyclic uniaxial tension would be enhanced if the mTORC1 signaling pathway was activated.

Predicting the Benefit of Adjuvant Aromatase Inhibitor Therapy in Postmenopausal Breast Cancer Patients with Phosphorylated S6K1 Expression Status / 한국유방암학회지

PURPOSE: Phosphorylated ribosomal S6 kinase 1 (pS6K1) is a major downstream regulator of the mammalian target of rapamycin (mTOR) pathway. Recent studies have addressed the role of S6K1 in adipogenesis. pS6K1 may affect the outcome of estrogen depletion therapy in patients with hormone-sensitive breast cancer due to its association with adipogenesis and increased local estrogen levels. This study aimed to investigate the potential of pS6K1 as a predictive marker of adjuvant aromatase inhibitor (AI) therapy outcome in postmenopausal or ovarian function-suppressed patients with hormone-sensitive breast cancer.METHODS: Medical records were retrospectively reviewed in postmenopausal or ovarian function-suppressed patients with estrogen receptor-positive and node-positive primary breast cancer. pS6K1 expression status was scored on a scale from 0 (negative) to 3+ (positive) based on immunohistochemical analysis.RESULTS: A total of 428 patients were eligible. The median follow-up duration was 44 months (range, 1–90). In patients with positive pS6K1 expression, AIs significantly improved disease-free survival (DFS) compared to selective estrogen receptor modulators (SERMs) (5 year-DFS: 83.5% vs. 50.7%, p = 0.016). However, there was no benefit of AIs on DFS in the pS6K1 negative group (5 year-DFS 87.6% vs. 91.4%, p = 0.630). On multivariate analysis, AI therapy remained a significant predictor for DFS in the pS6K1 positive group (hazard ratio, 0.39; 95% confidence interval, 0.16–0.96; p = 0.041). pS6K1 was more effective in predicting the benefit of AI therapy in patients with ages < 50 (p = 0.021) compared to those with ages ≥ 50 (p = 0.188).CONCLUSION: pS6K1 expression may predict AI therapy outcomes and serve as a potential predictive marker for adjuvant endocrine therapy in postmenopausal and ovarian function-suppressed patients with hormone-sensitive breast cancer. AIs may be more effective in patients with pS6K1 positive tumors, while SERM could be considered an alternative option for patients with pS6K1 negative tumors.

Effects of Electroacupuncture on Mammalian Target of Rapamycin/70-KD Ribosomal Protein S6 Kinase Pathway in Gastrocnemius Muscle in Denervated Rats / 中国康复理论与实践

@#Objective To explore the effects and mechanism of electroacupuncture (EA) on denervation-induced atrophy in rats. Methods A total of 18 male Sprague-Dawley rats were divided into sham group (n=6), model group (n=6) and EA group (n=6). The latter two groups were clamped right sciatic nerve to establish atrophy model of skeletal muscle. On the second day after modeling, EA group accepted electroacupuncture on right Zusanli (ST36) and Huantiao (GB30) for two weeks. Their gastrocnemius muscles were obtained after intervention, and the wet weight ratio of the gastrocnemius muscles was calculated. The cross-sectional area (CSA) and diameter of muscle fibers were measured after HE staining. The protein expression of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), 70-KD ribosomal protein S6 kinase (p70S6K) and phosphorylated p70S6k (p-p70S6k) was tested with Western blotting. The gene expression of mTOR and p70S6K was detected with real-time quantitative polymerase chain reaction. Results Compared with the sham group, the wet weight ratio of the gastrocnemius muscle, CSA and diameter of the muscle fibers decreased in the model group and EA group (P<0.001), which were more in EA group than in the model group (P<0.01); the protein expression of mTOR, p-mTOR, p70S6K and p-p70S6K increased in the model group (P<0.01), and increased more in EA group (P<0.05); the gene expression of mTOR and p70S6K increased in the model group (P<0.05) , and increased more in EA group (P<0.05).Conclusion Electroacupuncture delays the atrophy of denervated skeletal muscles, which may relate to activation of mTOR/p70S6K signal pathway to impact synthesis of skeletal muscle proteins.