0.05), suggesting that clinical trial could be made for the cultured mycelia

BACKGROUND:Estrogen signaling pathway for interaction between aromatase and estrogen-related receptor may exist in bone marrow mesenchymal stem cel s, which is used for regulating biological activity of bone marrow mesenchymal stem cel s. OBJECTIVE:To observe the expression of aromatase and estrogen-related receptors in adult bone marrow mesenchymal stem cel s during osteogenic differentiation. METHODS:Bone marrow mesenchymal stem cel s were respectively cultured in low-glucose DMEM medium (control group) and osteogenic induction medium (induction group). Cel proliferation and calcium deposition were determined by MTT assay and alizarin red staining, respectively. The expression of aromatase, estrogen receptorα, estrogen receptorβ, and estrogen-related receptorαduring osteogenic differentiation were determined by real-time PCR and western blot analysis. Estradiol levels in supernatants and lysates were detected by ELISA method. RESULTS AND CONCLUSION:In the induction group, the proliferation ability of bone marrow mesenchymal stem cel s was the strongest at 72 hours of culture;while there were a great amount of calcium nodules formed at 21 days of culture. Results from PCR and western blot assay showed that the expression of aromatase and estrogen receptorαwas improved in the induction group, but the expression of estrogen-related receptorαwas inhibited. There was no difference in the expression of estrogen receptorβbetween the two groups. ELISA results indicated that the level of estradiol in the supernatant of induction group was the highest. These findings indicate that aromatase, estrogen receptorα, estrogen receptorβand estrogen-related receptorαare al involved in osteogenesis of bone marrow mesenchymal stem cel s. Moreover, estradiol can be synthesized and secreted in bone marrow mesenchymal stem cel s, and most likely, promote the osteogenic differentiation of bone marrow mesenchymal stem cel s by related receptor pathway.

Genetic mutations in triggering receptor expressed on myeloid cells 2 (TREM2) have been linked to a variety of neurodegenerative diseases including Alzheimer’s disease, amyotrophic lateral sclerosis, frontotemporal dementia and Parkinson’s disease. In the brain, TREM2 is highly expressed on the cell surface of microglia, where it can transduce signals to regulate microglial functions such as phagocytosis. To date, mechanisms underlying intracellular trafficking of TREM2 remain elusive. Mutations in the presenilin 1 (PS1) catalytic subunit of the γ-secretase complex have been associated with increased generation of the amyloidogenic Aβ (amyloid-β) 42 peptide through cleavage of the Aβ precursor amyloid precursor protein. Here we found that TREM2 interacts with PS1 in a manner independent of γ-secretase activity. Mutations in TREM2 alter its subcellular localization and affects its interaction with PS1. Upregulation of PS1 reduces, whereas downregulation of PS1 increases, steady-state levels of cell surface TREM2. Furthermore, PS1 overexpression results in attenuated phagocytic uptake of Aβ by microglia, which is reversed by TREM2 overexpression. Our data indicate a novel role for PS1 in regulating TREM2 intracellular trafficking and pathophysiological function.

ObjectiveTo investigate the protective effect of Zhuangtongyin on the Middle Cerebral Artery Occlusion （MCAO） model by modulating ferroptosis through the Nrf2-SCL7A11/xCT-Gpx4 pathway and its underlying mechanism. MethodsC57BL/6J mice were randomly divided into Sham operation group （Sham）， model group （MCAO）， low-dose Zhuangtongyin group （ZTY-L）， high-dose Zhuangtongyin group（ZTY-H）， with 5 mice in each group. The MCAO group was modelled by silica gel embolization， the middle cerebral artery of mice was embolized for 1h， then the silica gel was pulled out and reperfusion was performed after 72 h； and the other operations in the Sham group were the same as those in the MCAO group except that the thread plug was not inserted. The neural function of mice was evaluated by Zea-Longa method. TTC staining was used to evaluate the volume of cerebral infarction. The level of brain injury was evaluated by HE staining and Nissl staining. Prussian blue staining and the expression of iron transport-related carrier receptors TfR1 and DMT1 on mRNA level was detected by qPCR to evaluate the iron ion deposition level in mice brain. The expression of lipid peroxidation-related gene ACSL4 on mRNA level was detected by qPCR， and the content of 4-HNE was detected by ELISA kit to evaluate the lipid peroxidation level of mice brain. The expressions of ferroptosis marker PTGS2 mRNA level was detected by qPCR. The expressions of Nrf2， SCL7A11/xCT， Gpx4 in mice brain tissue were detected by Western-blot and immunofluorescence. ResultsZhuangtongyin improved the nerve function of mice after MCAO （P＜0.05） and the cerebral infarction volume of mice （P＜0.05） and alleviate the pathological injury of cerebral cortex cells after MCAO operation. Zhuangtongyin attenuated the accumulation of trivalent iron ions in the brain tissue of mice following MCAO. Additionally， Zhuangtongyin downregulated the expression of TfR1 and DMT1 mRNA （P＜0.001）， a transporter associated with cellular iron ion uptake， in the brains of post-MCAO mice. Furthermore， Zhuangtongyin reduced levels of lipid peroxidation product 4-HNE （P＜0.001） and suppressed ACSL4 mRNA expression in brain tissue post-MCAO （P＜0.001）. Besides， Zhuangtongyin downregulated the expression of PTGS2 mRNA （P＜0.001）， in the brains of post-MCAO mice. Zhuangtongyin increased the expression of nrf2 into the nucleus （P＜0.001）， and increased the expression of xCT and Gpx4 in neurons after MCAO （P＜0.001）. ConclusionZhuangtongyin can enhance the nerve function and reduce cerebral infarction volume in MCAO/R mice， alleviate the pathological damage of cerebral cortex cells， and modulate the expression of key signaling molecules in the Nrf2-SCL7A11/xCT-Gpx4 pathway. Therefore， it is suggested that the mechanism by which Zhuangtongyin improves MCAO/R injury in mice may involve regulating ferroptosis through the Nrf2-SCL7A11/xCT-GPX4 pathway.