Association of ADIPOR1 polymorphisms with bone mineral density in postmenopausal Korean women

Distinct roles of ADIPOR1 and ADIPOR2: A pan-cancer analysis

INTRODUCTION

AdipoR1 and AdipoR2 proteins, encoded by ADIPOR1 and ADIPOR2 genes respectively, are the receptors of adiponectin secrected by adipose tissue. Increasing studies have identified the vital role of adipose tissue in various diseases, including cancers. Hence, there is an urgent need to explore the roles of AdipoR1 and AdipoR2 in cancers.

METHODS

We conducted a comprehensive pan-cancer analysis for the roles of AdipoR1 and AdipoR2 via several public databases, including expression differences, prognostic value, and the correlations with tumor microenvironment, epigenetic modification, and drug sensitivity.

RESULTS

Both ADIPOR1 and ADIPOR2 genes are dysregulated in most cancers, but their genomic alteration frequencies are low. In addition, they are also correlated with the prognosis of some cancers. Although they are not strongly correlated with tumor mutation burden (TMB) or microsatellite instability (MSI), ADIPOR1/2 genes display a significant association with cancer stemness, tumor immune microenvironment, immune checkpoint genes (especially CD274 and NRP1), and drug sensitivity.

DISCUSSION

ADIPOR1 and ADIPOR2 play critical roles in diverse cancers, and it is a potential strategy to treat tumors through targeting ADIPOR1 and ADIPOR2.

Correlation of ADIPOQ Gene Single Nucleotide Polymorphisms with Bone Strength Index in Middle-Aged and the Elderly of Guangxi Mulam Ethnic Group

BACKGROUND

Osteoporosis (OP) is a common orthopedic disease in the elderly, and Adiponectin (ADIPOQ) is closely related to bone metabolism.

OBJECTIVE

To determine the relationship between five single nucleotide polymorphism (SNP) loci in the ADIPOQ gene and osteoporosis in middle-aged and elderly Mulam subjects in Hechi, Guangxi.

METHODS

This case-control study included 297 middle-aged and elderly Mulam subjects with normal bone mass, 49 subjects with reduced bone mass, and 38 subjects with osteoporosis. Five loci (rs266729, rs1063539, rs2241766, rs3774261, rs710445) of the ADIPOQ in the Mulam subjects were genotyped using SNP with multiple-base extension.

RESULTS

The bone strength index (SI) of middle-aged and elderly Mulam subjects showed an overall decreasing trend when the subjects were older. Age, muscle mass, and subcutaneous fat content were the main factors influencing the SI in Mulam subjects. The GC genotype of rs266729 and the GA and GG genotypes of rs710445 were significantly correlated with risk of bone loss (p < 0.05). rs2241766 and rs1063539 showed strong LD (D' > 0.8, r² > 0.33). rs710445 and rs266729 loci and rs3774261 and rs2241766 loci showed complete LD (D' = 1).

CONCLUSIONS

The GC genotype at rs266729 of the ADIPOQ gene, the GA and GG genotypes at rs710445, and the haplotypes CCGAA and GGTAG correlated with osteoporosis (p < 0.05). The allele C of rs1063539, rs266729 and rs710445 may afford protection for osteoporosis. The allele G may be the genetic susceptibility gene for osteoporosis, increasing the risk of osteoporosis.

Adiponectin Receptor gene Polymorphisms are Associated with Kidney Function in Elderly Japanese Populations

Aim: Adiponectin exhibits its biological effects through adiponectin receptors (AdipoR1 and AdipoR2), which are distributed in the kidneys, and activation of those receptors could prevent or ameliorate diabetic nephropathy. This study aimed to evaluate the associations between AdipoR single nucleotide polymorphisms (SNPs) and kidney function in an elderly Japanese population.

Methods: A total of 271 elderly Japanese volunteers underwent anthropometric and laboratory tests (cystatin C-based eGFR and total and high molecular weight adiponectin levels at baseline and a follow-up visit). Genotype data were obtained for the selected 7 and 5 AdipoR1 and AdipoR2 SNPs, respectively.

Results: In a cross-sectional analysis at baseline, we found a significant association between the AdipoR2 SNP rs12230440 and kidney function; eGFRcys tended to increase as the number of carriers of T alleles increased after adjustment for covariates and Bonferroni correction, although the association of the SNP and annual eGFR decline could not be identified in the longitudinal data. Regarding the variants rs16850797, rs11061925, and rs10773983, each of the allele G, allele C, and allele G showed nominally significant associations with higher eGFRcys. However, this failed to reach significance after Bonferroni correction.

Conclusion: Here, an AdipoR2 SNP was associated with kidney function, suggesting that the effects of this polymorphism on adiponectin receptor may affect kidney function in the elderly Japanese population.

Adiponectin signaling and its role in bone metabolism

Adiponectin, the most prevalent adipo-cytokine in plasma plays critical metabolic and anti-inflammatory roles is fast emerging as an important molecular target for the treatment of metabolic disorders. Adiponectin action is critical in multiple organs including cardio-vascular system, muscle, liver, adipose tissue, brain and bone. Adiponectin signaling in bone has been a topic of active investigation lately. Human association studies and multiple mice models of gene deletion/modification failed to define a clear cause and effect of adiponectin signaling in bone. The most plausible reason could be the multimeric forms of adiponectin that display differential binding to receptors (adipoR1 and adipoR2) with cell-specific receptor variants in bone. Discovery of small molecule agonist of adipoR1 suggested a salutary role of this receptor in bone metabolism. The downstream signaling of adipoR1 in osteoblasts involves stimulation of oxidative phosphorylation leading to increased differentiation via the likely suppression of wnt inhibitor, sclerostin. On the other hand, the inflammation modulatory effect of adiponectin signaling suppresses the RANKL (receptor activator of nuclear factor κ-B ligand) - to - OPG (osteprotegerin) ratio in osteoblasts leading to the suppression of osteoclastogenic response. This review will discuss the adiponectin signaling and its role in skeletal homeostasis and critically assess whether adipoR1 could be a therapeutic target for the treatment of metabolic bone diseases.

Globular adiponectin reverses osteo-sarcopenia and altered body composition in ovariectomized rats

Adiponectin regulates various metabolic processes including glucose flux, lipid breakdown and insulin response. We recently reported that adiponectin receptor1 (adipoR1) activation by a small molecule reverses osteopenia in leptin receptor deficient db/db (diabetic) mice. However, the role of adiponectin in bone metabolism under the setting of post-menopausal (estrogen-deficiency) osteopenia and associated metabolic derangements has not been studied. Here, we studied the therapeutic effect of the globular form of adiponectin (gAd), which is predominantly an adipoR1 agonist, in aged ovariectomized (OVX) rats and compared it with standard-of-care anti-osteoporosis drugs. In OVX rats with established osteopenia, gAd completely restored BMD and load bearing capacity and improved bone quality. Skeletal effects of gAd were comparable to PTH (osteoanabolic) but better than alendronate (anti-catabolic). Both osteoanabolic and anti-catabolic mechanisms led to the anti-osteoporosis effect of gAd. In cultured osteoblasts and bones, gAd increased a) adipoR1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression to promote mitochondrial respiration, which likely fueled osteoblast differentiation, b) suppressed sclerostin (a wnt antagonist) in a sirtuin1-dependent manner and c) decreased receptor-activator of nuclear factor κB ligand (RANKL) to achieve its anti-catabolic effect. The OVX-induced sarcopenia and insulin resistance were also improved by gAd. We conclude that gAd has therapeutic efficacy in estrogen deficiency-induced osteoporosis, sarcopenia and insulin resistance and hold metabolic disease modifying potential in postmenopausal women.

Relationship between adipokines and lipid profile in postmenopausal women with different apolipoprotein E genotypes

The aim of the authors of this study was to clarify the relationships among apolipoprotein E (ApoE) genotype, blood pressure, lipid profile, serum leptin, and adiponectin in healthy postmenopausal women. The study was conducted between March 2011 and December 2012 on 266 participants aged 50-65 years from the Institute of Rural Health in Lublin, Poland. Results showed that women had four combinations of genotypes: ɛ2/ɛ3, ɛ3/ɛ3, ɛ3/ɛ4, and ɛ4/ɛ4. Carriers of different genotypes did not differ in terms of age, body mass index (BMI), blood pressure, total cholesterol, high-density lipoprotein (HDL) cholesterol, and adiponectin levels. Mean low-density lipoprotein (LDL) cholesterol levels were higher in ε4 carriers compared to non-carriers. Fasting serum leptin concentrations were higher in homozygotes ɛ4/ɛ4. Leptin correlated positively with BMI in all study groups and with LDL in ɛ2/ɛ3, ɛ3/ɛ3, and ɛ3/ɛ4. Adiponectin correlated negatively with triglycerides in ɛ2/ɛ3, ɛ3/ɛ3, and ɛ3/ɛ4 and positively with HDL in ɛ2/ɛ3 carriers. Adipokines were not associated with blood pressure. Multiple regression analyses demonstrated associations among leptin, ApoE ɛ4/ɛ4, BMI, and LDL, and among adiponectin, BMI, and triglycerides. In healthy postmenopausal women ɛ4/ɛ4 genotype was associated with lower leptin levels. Homozygosity ɛ4/ɛ4 was associated with a more atherogenic lipid profile and possibly dysregulation of leptin and adiponectin signaling in lipid metabolism.