Obesity predisposes to cancer and a virtual universality of nonalcoholic fatty liver disease (NAFLD). However, the impact of hepatic steatosis on liver metastasis is enigmatic. We find that while control mice were relatively resistant to hepatic metastasis, those which were lipodystrophic or obese, with NAFLD, had a dramatic increase in breast cancer and melanoma liver metastases. NAFLD promotes liver metastasis by reciprocal activation initiated by tumor-induced triglyceride lipolysis in juxtaposed hepatocytes. The lipolytic products are transferred to cancer cells via fatty acid transporter protein 1, where they are metabolized by mitochondrial oxidation to promote tumor growth. The histology of human liver metastasis indicated the same occurs in humans. Furthermore, comparison of isolates of normal and fatty liver established that steatotic lipids had enhanced tumor-stimulating capacity. Normalization of glucose metabolism by metformin did not reduce steatosis-induced metastasis, establishing the process is not mediated by the metabolic syndrome. Alternatively, eradication of NAFLD in lipodystrophic mice by adipose tissue transplantation reduced breast cancer metastasis to that of control mice, indicating the steatosis-induced predisposition is reversible.

Objective Matrix Gla protein (MGP) is a potent calcification inhibitor. Mgp-/- mice display increased proportion of brown adipose tissue. However, whether MGP is involved in fat metabolism remains unclear. This study aims to investigate the involvement. Methods Expression of adipocyte differentiation markers was examined by RT-qPCR. Adipocyte formation was assessed by Oil Red staining. Serum triglyceride, cholesterol, and desphosphorylated-uncarboxylated MGP (dp-ucMGP) were quantified by ELISA. Visceral fat was detected by bioelectrical impedance analysis. Results MGP is highly expressed in visceral fat. MGP expression is induced during preadipocyte differentiation. Knockout of MGP leads to retardation of 3T3-L1 differentiation. Intracellular triglyceride amount is impaired while glycerol release is increased in MGP-depleted cells. Serum dp-ucMGP level is significantly increased in individual with higher visceral fat index (VFI) and waist height ratio (WHtR), but not body mass index (BMI). Additionally, dp-ucMGP positively correlates to low-density lipoprotein cholesterol (LDL-C) level. Conclusions MGP is involved in fat metabolism and serum inactive MGP level is associated with visceral fat. Our study uncovers for the first time the link between MGP and fat metabolism, and sheds light on the potential of dp-ucMGP as a novel serum marker.

Increasing evidence uncover the essential role of lncRNAs in bone metabolism and the association of lncRNA with genetic risk of osteoporosis. However, whether lncRNA Neat1 is involved remains largely unknown. In the present study, we found that Neat1 is induced by osteoclastic differentiation stimuli. Knockdown of Neat1 attenuates osteoclast formation whereas overexpression of Neat1 accelerates osteoclast formation. In vivo evidence demonstrated that enhanced Neat1 expression stimulates osteoclastogenesis and reduces bone mass in mice. Mechanically, Neat1 competitively binds with miR‐7 and blocks its function for regulating PTK2. Intergenic SNP rs12789028 acts as allele‐specific long‐range enhancer for NEAT1 via chromatin interactions. We establish for the first time that Neat1 plays an essential role in osteoclast differentiation, and provide genetic mechanism underlying the association of NEAT1 locus with osteoporosis risk. These results enrich the current knowledge of NEAT1 function, and uncover the potential of NEAT1 as a therapeutic target for osteoporosis.

Adenovirus-mediated delivery of Sema3A alleviates rheumatoid arthritis in a serum-transfer induced mouse model Adenovirus-mediated delivery of Sema3A alleviates rheumatoid arthritis in a serum-transfer induced mouse model

Osteoporosis is a common bone disease characterized by loss of bone mass, reduced bone strength, and deterioration of bone microstructure. ROS-induced oxidative stress plays an important role in osteoporosis. However, the biomarkers and molecular mechanisms of oxidative stress are still unclear. We obtained the datasets from the Gene Expression Omnibus (GEO) database, and performed differential analysis, Venn analysis, and weighted correlation network analysis (WGCNA) analysis out the hub genes. Then, the correlation between inflammatory factors and hub genes was analyzed, and a Mendelian randomization (MR) analysis was performed on cytokines and osteoporosis outcomes. In addition, “CIBERSORT” was used to analyze the infiltration of immune cells and single-cell RNA-seq data was used to analyze the expression distribution of hub genes and cell–cell communications. Finally, we collected human blood samples for RT-qPCR and Elisa experiments, the miRNA-mRNA network was constructed using the miRBase database, the 3D structure was predicted using the RNAfold, Vfold3D database, and the drug sensitivity analysis was performed using the RNAactDrug database. We obtained three differentially expressed genes associated with oxidative stress: DBH, TAF15, and STAT4 by differential, WGCNA clustering, and Venn screening analyses, and further analyzed the correlation of these 3 genes with inflammatory factors and immune cell infiltration and found that STAT4 was significantly and positively correlated with IL-2. Single-cell data analysis showed that the STAT4 gene was highly expressed mainly in dendritic cells and monocytes. In addition, the results of RT-qPCR and Elisa experiments verified that the expression of STAT4 was consistent with the previous analysis, and a significant causal relationship between IL-2 and STAT4 SNPs and osteoporosis was found by Mendelian randomization. Finally, through miRNA-mRNA network and drug sensitivity analysis, we analyzed to get Palbociclib/miR-141-3p/STAT4 axis, which can be used for the prevention and treatment of osteoporosis. In this study, we proposed the Palbociclib/miR-141-3p/STAT4 axis for the first time and provided new insights into the mechanism of oxidative stress in osteoporosis.