Irisin suppresses pancreatic ß cell pyroptosis in T2DM by inhibiting the NLRP3-GSDMD pathway and activating the Nrf2-TrX/TXNIP signaling axis.

BACKGROUND: Irisin plays a key role in metabolic diseases, including type 2 diabetes mellitus (T2DM). However, the mechanism underlying the link between irisin and the development of T2DM, particularly in pancreatic islet ß-cells, remains unknown. METHODS: In vitro, Min6 cells were treated with high glucose (HG) to generate T2DM cell models. GSDMD-N staining, Western blotting assays, and ELISA were performed to measure the expression levels of GSDMD, caspase 1, IL-1ß, and IL-18. Next, the NLRP3 stimulator, ATP, was used to assess the effect of irisin on NLRP3 inflammasome. To evaluate the function of the Nrf2-TrX/TXNIP signaling axis, the Nrf2 inhibitor ML385 was used. For in vivo assessment, we first established T2DM model mice. Then, hematoxylin and eosin (H&E) staining was performed to observe the islet morphology, and the immunofluorescence technique was used to examine the mass of α and ß cells. To confirm the role of the Nrf2-TrX/TXNIP signaling axis, ML385 was injected into the mice. Immunofluorescence of Nrf2, caspase 1, and GSDMD was detected in the islet cells of the model mice to verify the results. RESULTS: We found that irisin treatment significantly decreased the expression of GSDMD-N (P31) and cleaved caspase-1 (p20), decreased caspase1 activity, and inhibited the secretion of IL-1ß and IL-18 in HG-treated Min6 cells. We also found that irisin inhibited oxidative stress and NLRP3 expression by activating the Nrf2-TrX/TXNIP signaling axis. Additionally, in the T2DM model mice, irisin enhanced the function of islet cells, decreased insulin resistance, and preserved the morphology of pancreatic islets. CONCLUSION: We showed in this study that irisin can be used for treating pyroptosis in HG-induced islet ß-cells and T2DM model mice. We also found that irisin inhibits pyroptosis and oxidative stress by inhibiting the NLRP3-GSDMD pathway and activating the Nrf2-TrX/TXNIP signaling axis.

Irisin attenuates pyroptosis in high glucose-induced pancreatic beta cells via the miR-133a-3p/FOXO1 axis.

INTRODUCTION: Irisin is closely related to type 2 diabetes mellitus (T2DM) and other metabolic diseases. It can improve the homeostasis of T2DM. MiR-133a-3p is decreased in the peripheral blood of patients with T2DM. Forkhead box protein O1 (FOXO1) is widely expressed in beta-cells and affects the occurrence of diabetes through transcriptional regulation and signalling pathway regulation. MATERIAL AND METHODS: The miR-133a-3p inhibitor was constructed to verify the effect of irisin on pyroptosis through miR-133a-3p. Next, we predicted the presence of targeted binding sequences between FOXO1 and miR-133a-3p by bioinformatics software, which was then confirmed with a double fluorescence assay. Finally, the FOXO1 overexpression vector was used to further verify the effect of irisin through the miR-133a-3p/FOXO1 axis. RESULTS: We first observed that irisin inhibited the protein levels of N-terminal gasdermin D (GSDMD-N) and cleaved caspase-1 and the secretion of interleukins (IL): IL-1beta and IL-18 in Min6 cells treated with high glucoes (HG). Irisin inhibited pyroptosis of Min6 cells treated with HG by reinforcing miR-133a-3p. Then, FOXO1 was validated to be the target gene of miR-133a. Both miR-133a-3p inhibitor and overexpression of FOXO1 restrained the force of irisin on pyroptosis in HG-induced Min6 cells. CONCLUSION: We explored the protective effect of irisin on HG-induced pyroptosis of islet b-cells in vitro and explained its mechanism of inhibiting pyroptosis through the miR-133a-3p/FOXO1 axis, to provide a theoretical basis for finding new molecular targets to delay beta-cell failure and the treatment of T2DM.

The correlation between the serum LDL-C/Apo B ratio and lumbar bone mineral density in young adults.

BACKGROUND: Numerous studies have confirmed that atherosclerosis is related to osteoporosis (OP), and patients with atherosclerosis are more prone to OP. The ratio of low-density lipoprotein cholesterol (LDL-C) to apolipoprotein B (Apo B) is the valid indicator of atherosclerosis. Nevertheless, conclusions regarding relation between LDL-C/Apo B ratio and bone mineral density (BMD) are still lacking. As a result, this study concentrated on investigating the relationship between LDL-C/Apo B ratio and lumbar BMD in the young adult population according to the National Health and Nutrition Examination Survey (NHANES). METHODS: Information of 2027 young adults (age 20-40 years) from NHANES database was obtained for this cross-sectional study. The correlation between serum LDL-C/Apo B ratio and lumbar BMD was explored through weighted multiple stratified linear regression, while the smooth curve fitting model was utilized for analyzing nonlinear relation. In the nonlinear relation, the inflection point was calculated by saturation threshold analysis. The weighted two-piecewise linear regression model was constructed. RESULTS: After covariates were adjusted, the relation between serum LDL-C/Apo B ratio and lumbar BMD varied by sex (males: ß = -0.0126, 95% CI -0.0892, 0.0640; females: ß = 0.0322, 95% CI -0.0367, 0.1011). By performing age-stratified subgroup analysis, the association also varied by age and sex. Males aged 20-30 years presented a negative trend (ß = -0.0570, 95% CI -0.1656, 0.0517), and males with the age of 31-40 years showed a positive trend (ß = 0.0810, 95% CI -0.0312, 0.1931). Women showed a positive trend by age (females of 20-30 years: ß = 0.0051, 95% CI -0.0935, 0.1036; females of 31-40 years: ß = 0.0265, 95% CI -0.0767, 0.1296). In race-stratified subgroup analysis, the relations varied by sex and race. To be specific, non-Hispanic black males showed a negative trend (ß = -0.0754, 95% CI -0.2695, 0.1188), and males of other races exhibited a positive trend. The trend was positive for women of all races. CONCLUSION: Differences were detected in the association between serum LDL-C/Apo B ratio and lumbar BMD among cases aged 20-40 years across sex, age, and race/ethnicity. In addition, the inflection points in U-shaped relationships were also calculated.

The correlation between serum total alkaline phosphatase and bone mineral density in young adults.

BACKGROUND: Elevated total alkaline phosphatase (T-ALP) levels are usually indicative of enhanced osteoblastic activity and bone conversion status and are thus considered as a key factor needed for fresh bone mineralization and synthesis. To date, there is no consistent conclusion on the association between the serum T-ALP levels and bone mineral density (BMD). Therefore, the present study focused on exploring the association of serum T-ALP with lumbar BMD among young adults. METHODS: The present cross-sectional study included 6,331 subjects included in the National Health and Nutrition Examination Survey (NHANES) during 2011-2016. The participants aged 20-40 years included 3,349 males and 2,982 females. Serum T-ALP was our main variable, lumbar BMD was our outcome variable, and additional variables were the possible impact modifiers. The relations were analysed by the trend study, weighted multiple linear regression models, smooth curve fitting, and stratified analyses. RESULTS: In a completely corrected multiple regression model, a negative association between serum T-ALP and lumbar BMD was discovered (ß = -0.0007, 95% CI: -0.0009- -0.0005, P < 0.000001). After converting the continuous variable serum T-ALP into the categorical one, the significant negative association was still observed (P < 0.001), and in the subgroup and smooth curve fitting analyses, this negative correlation remained significant, too. CONCLUSIONS: Our study results indicated that serum T-ALP was negatively associated with lumbar BMD among young adults. Serum T-ALP measurement in the near future might become an effective biomarker to diagnose and treat osteoporosis on time.

Knockdown of Malat1 alleviates high-glucose-induced angiogenesis through regulating miR-205-5p/VEGF-A axis.

Diabetic retinopathy (DR), characterized by intraretinal vessel formation, is a major complication in diabetes. Neovascularization is an important characteristic of DR, but its formation mechanism remains unclear. In this research, Malat1, miR-205-5p, and VEGF-A levels in high glucose (HG) treat-human retinal microvascular endothelial cells (hRMECs) was detected with qRT-PCR. CCK-8 assay, transwell assay, and tube formation assay was applied to access hRMEC viability, migration, and angiogenesis. Expression level of endothelial-mesenchymal transition (EndMT) markers (VE-cadherin, FSP1, and α-SMA) was detected by western blotting assay. Interaction among Malat1, miR-205-5p, and VEGF-A was confirmed by dual-luciferase reporter assay. Furthermore, in vivo DR mouse model was induced, and the effect of Malat1 on DR and EndMT markers was confirmed through hematoxylin-eosin (HE) staining and western blotting. As a result, Malat1 and VEGF-A was upregulated while miR-205-5p was suppressed under HG conditions. Malat1 could sponge miR-205-5p to regulate VEGF-A expression. Malat1 knockdown inhibited hRMEC proliferation, migration, and tube formation by targeting miR-205-5p under HG conditions. Furthermore, inhibition of Malat1 prevented the HG-induced EndMT process. In summary, Malat1 knockdown diminished hRMEC dysfunctions by regulating miR-205-5p/VEGF-A, providing a useful insight for exploring new therapeutic target for DR.

miR-34a inhibits tumorigenesis of NSCLC via targeting SIRT6.

Non-small cell lung cancer (NSCLC) remains the leading cause of deaths around the world. Therefore, improving the diagnostic and treatments of NSCLC are urgently needed. The microRNA-34a (miR-34a) and SIRT6 are associated with NSCLC. miR-34a is downregulated in three NSCLC cells lines (A549, H460, and H1299). The functions of SIRT6 in NSCLC are controversial. Some reports have shown that SIRT6 is downregulated in NSCLC cells, while other reports have shown that SIRT6 is upregulated in NSCLC tissues as well as SIRT6 overexpression is associated with the poor prognosis of NSCLC. SIRT6 is a direct target of miR-34a in human keratinocytes (HKCs). However, the relationship between SIRT6 and miR-34a in NSCLC has not been investigated. In this study, we found that the SIRT6 was upregulated in NSCLC tissues while miR-34a was downregulated in NSCLC tissues compared with those in their normal counterparts. Overexpression of miR34a or downregulation of SIRT6 promoted A549 cells apoptosis, cell cycle arrest in vitro and further inhibited the tumor formation in vivo. SIRT6 was indeed the target gene of miR-34a, which was proved by the luciferase reporter data. Therefore, we conclude that SIRT6 was the target gene of miR-34a in NSCLC. miR-34a acted as a cancer suppressor in NSCLC via targeting the SIRT6.

Interaction between hypertension and HSP70 variants increase the risk of cerebral ischemia in Chinese Han population: an association study.

Cerebral infarction has become one of the leading diseases and a major mortality factor around the world. Atherosclerosis is recognized as one of the important causes of ischemic stroke. Recently, accumulating evidences have indicated that the anti-inflammatory and anti-apoptotic functions of the HSP70 family play an important role in cerebral ischemia. However, the association between HSP70 SNPs and ischemic stroke was also not well established. We chose 101 cases of cerebral ischemia and 100 healthy people from the Chinese Han population as our study subjects, and PCR-RFLP was employed to analyze HSP70 polymorphisms: HSP70-1+190G/C, HSP70-2+1267A/G and HSP70-hom+2437T/C. There were no significant differences in +1267A/G allele or genotype frequencies between patients with stroke and healthy controls. However, genotypes of +190CG and +2437TT were differentially distributed between the patients and controls. A significant difference of T allele distribution in the HSP70-hom+2437T/C site was observed. Logistic regression analysis indicated that genotypes of +190CG, +2437TT and T allele in HSP70-hom were risk factors of ischemic stroke. Moreover, the study has formulated that the interactions between hypertension and +190CG or +2437TT may increase the risks of ischemic stroke. The results from this study have suggested a clinical indicator for assessing the possibilities of cerebral stroke, and supply basis to clinicians to give precaution to people who are at risk of stroke.