Two novel pleiotropic loci associated with osteoporosis and abdominal obesity

Higher BMI and lower femoral neck strength in males with type 2 diabetes mellitus and normal bone mineral density

BACKGROUND

Type 2 diabetes mellitus (T2DM) and osteoporosis are two age-associated diseases. Body mass index (BMI) is positively associated with osteoporosis or osteopenia in T2DM population. Bone mineral density does not necessarily reflect the alterations in bone microarchitecture. Our aims were to investigate the relationship between BMI and femoral neck strength in males with T2DM and normal range of bone mineral density (BMD).

METHODS

This study enrolled 115 males (median age 53.3 years) with T2DM and normal BMD. Femoral neck strength indexes, including compression strength index (CSI), bending strength index (BSI), impact strength index (ISI), were calculated by parameters generated from Dual-energy X-ray absorptiometry software. Pearson correlation analysis was performed to evaluate the relationships between BMI and femoral neck strength variables.

RESULTS

Compared with T2DM-normal weight group, T2DM-overweight group and T2DM-obesity group had a higher femur neck and total femur BMDs. Cross sectional moment of inertia (CSMI), cross sectional area (CSA), section modulus (SM) were significantly higher (all p<0.05), and buckling ratio (BR) (6.35±2.08 vs 7.18±1.71) was lower in T2DM-obesity group than in T2DM-normal weight group. Compared with T2DM-normal weight group, CSI (all p<0.001), BSI (all p<0.001), ISI (all p<0.001) were significantly reduced in T2DM-obesity and T2DM-overweight groups. Pearson correlation analysis indicated that BMI was negatively correlated with CSI (r= - 0.457, p<0.001), BSI(r = -0.397, p<0.001), ISI (r = - 0.414, p<0.001).

CONCLUSIONS

Higher BMI is associated with lower femoral neck strength in males with T2DM and normal BMD. It implies that femoral neck fracture risk increases in obese and diabetic males, despite their high bone density.

The landscape of GWAS validation; systematic review identifying 309 validated non-coding variants across 130 human diseases

Background

The remarkable growth of genome-wide association studies (GWAS) has created a critical need to experimentally validate the disease-associated variants, 90% of which involve non-coding variants.

Methods

To determine how the field is addressing this urgent need, we performed a comprehensive literature review identifying 36,676 articles. These were reduced to 1454 articles through a set of filters using natural language processing and ontology-based text-mining. This was followed by manual curation and cross-referencing against the GWAS catalog, yielding a final set of 286 articles.

Results

We identified 309 experimentally validated non-coding GWAS variants, regulating 252 genes across 130 human disease traits. These variants covered a variety of regulatory mechanisms. Interestingly, 70% (215/309) acted through cis-regulatory elements, with the remaining through promoters (22%, 70/309) or non-coding RNAs (8%, 24/309). Several validation approaches were utilized in these studies, including gene expression (n = 272), transcription factor binding (n = 175), reporter assays (n = 171), in vivo models (n = 104), genome editing (n = 96) and chromatin interaction (n = 33).

Conclusions

This review of the literature is the first to systematically evaluate the status and the landscape of experimentation being used to validate non-coding GWAS-identified variants. Our results clearly underscore the multifaceted approach needed for experimental validation, have practical implications on variant prioritization and considerations of target gene nomination. While the field has a long way to go to validate the thousands of GWAS associations, we show that progress is being made and provide exemplars of validation studies covering a wide variety of mechanisms, target genes, and disease areas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01216-w.

A network pharmacology approach to explore and validate the potential targets of ginsenoside on osteoporosis

Background: Osteoporosis (OP) is determined as a chronic systemic bone disorder to increase the susceptibility to fracture. Ginsenosides have been found the anti-osteoporotic activity of in vivo and in vitro. However, its mechanism remains unknown.Methods: The potential mechanism of ginsenosides in anti-osteoporotic activity was identified by using network phamacology analysis. The active compounds of ginsenosides and their targets associated to OP were retrieved from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, Drug Bank, Pharmmapper, and Cytoscape. The Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis target genes were performed in String, Phenopedia, DisGeNET database, and Metascape software. The protein to protein interaction were created by String database and Cytoscape software. The molecular docking was used to investigate the interactions between active coumpounds and potential targets by utilizing SwissDock tool, UCSF Chimera, and Pymol software. Results: A total of eight important active ingredients and 17 potential targets related to OP treatment were subjected to analyze. GO analysis showed the anti-osteoporosis targets of ginsenoside mainly play a role in the response to steroid hormone. KEGG enrichment analysis indicated that ginsenoside treats OP by osteoblast differentiation signal pathway. Lastly, the molecular docking outcomes indicated that ginsenoside rh2 had a good binding ability with four target proteins IL1B, TNF, IFNG, and NFKBIA. Conclusion: IL1B, TNF, IFNG, and NFKBIA are the most important targets and osteoblast differentiation is the most valuable signaling pathways in ginsenoside for the treatment of OP, which might be beneficial to elucidate the mechanism concerned to the action of ginsenoside and might supply a better understanding of its anti-OP effects.

Serum Metabolite Profile Associated with Sex-Dependent Visceral Adiposity Index and Low Bone Mineral Density in a Mexican Population

Recent evidence shows that obesity correlates negatively with bone mass. However, traditional anthropometric measures such as body mass index could not discriminate visceral adipose tissue from subcutaneous adipose tissue. The visceral adiposity index (VAI) is a reliable sex-specified indicator of visceral adipose distribution and function. Thus, we aimed to identify metabolomic profiles associated with VAI and low bone mineral density (BMD). A total of 602 individuals from the Health Workers Cohort Study were included. Forty serum metabolites were measured using the targeted metabolomics approach, and multivariate regression models were used to test associations of metabolomic profiles with anthropometric, clinical, and biochemical parameters. The analysis showed a serum amino acid signature composed of glycine, leucine, arginine, valine, and acylcarnitines associated with high VAI and low BMD. In addition, we found a sex-dependent VAI in pathways related to primary bile acid biosynthesis, branched-chain amino acids, and the biosynthesis of pantothenate and coenzyme A (CoA). In conclusion, a metabolic profile differs by VAI and BMD status, and these changes are gender-dependent.

MicroRNA-29a in Osteoblasts Represses High-Fat Diet-Mediated Osteoporosis and Body Adiposis through Targeting Leptin

Skeletal tissue involves systemic adipose tissue metabolism and energy expenditure. MicroRNA signaling controls high-fat diet (HFD)-induced bone and fat homeostasis dysregulation remains uncertain. This study revealed that transgenic overexpression of miR-29a under control of osteocalcin promoter in osteoblasts (miR-29aTg) attenuated HFD-mediated body overweight, hyperglycemia, and hypercholesterolemia. HFD-fed miR-29aTg mice showed less bone mass loss, fatty marrow, and visceral fat mass together with increased subscapular brown fat mass than HFD-fed wild-type mice. HFD-induced O₂ underconsumption, respiratory quotient repression, and heat underproduction were attenuated in miR-29aTg mice. In vitro, miR-29a overexpression repressed transcriptomic landscapes of the adipocytokine signaling pathway, fatty acid metabolism, and lipid transport, etc., of bone marrow mesenchymal progenitor cells. Forced miR-29a expression promoted osteogenic differentiation but inhibited adipocyte formation. miR-29a signaling promoted brown/beige adipocyte markers Ucp-1, Pgc-1α, P2rx5, and Pat2 expression and inhibited white adipocyte markers Tcf21 and Hoxc9 expression. The microRNA also reduced peroxisome formation and leptin expression during adipocyte formation and downregulated HFD-induced leptin expression in bone tissue. Taken together, miR-29a controlled leptin signaling and brown/beige adipocyte formation of osteogenic progenitor cells to preserve bone anabolism, which reversed HFD-induced energy underutilization and visceral fat overproduction. This study sheds light on a new molecular mechanism by which bone integrity counteracts HFD-induced whole-body fat overproduction.

Association of Fibroblast Growth Factor 23 With Ischemic Stroke and Its Subtypes: A Mendelian Randomization Study

Fibroblast growth factor 23 (FGF23), which is involved in the regulation of vitamin D, is an emerging independent risk factor for cardiovascular diseases. Previous studies have demonstrated a positive association between FGF23 and stroke. In this study, we aimed to assess the association of FGF23 with ischemic stroke and its subtypes by applying a Mendelian randomization (MR) framework. Five genetic variants obtained from a genome-wide association study involving 16,624 European subjects were used as valid instruments of circulating FGF23 levels. MR was applied to infer the causality of FGF23 levels and the risk of ischemic stroke using data from the MEGASTROKE consortium. Subsequently, several MR analyses, including inverse-variance weighted meta-analysis, MR-Egger, weighted median estimate (WME), MR Pleiotropy Residual Sum and Outlier were performed. The heterogeneity test analysis, including Cochran's Q, I 2 test and leave-one-out analysis were also applied. Furthermore, potential horizontal/vertical pleiotropy was assessed. Lastly, the power of MR analysis was tested. Three validated variants were found to be associated with circulating FGF23 levels and were used for further investigation. We found that high expression level of FGF23 was not associated with any ischemic stroke. However, a causal association between genetically predicted FGF23 levels and the risk of large-artery atherosclerotic stroke (LAS) was significant, with an odds ratio of 1.74 (95% confidence interval = 1.08-2.81) per standard deviation increase in circulating FGF23 levels. Our findings provide support for the causal association between FGF23 and LAS, and therefore, offer potential therapeutic targets for LAS. The specific roles of FGF23 in LAS and associated molecules require further investigation.