AUTHOR=Zhou Hao-long , Wei Mu-hong , Di Dong-sheng , Zhang Ru-yi , Zhang Jian-li , Yuan Ting-ting , Liu Qian , Zhou Ting-ting , Huang Qin , Wang Qi 

TITLE=Association between SEMA3A signaling pathway genes and BMD/OP risk: An epidemiological and experimental study

JOURNAL=Frontiers in Endocrinology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.1014431

DOI=10.3389/fendo.2022.1014431

ISSN=1664-2392

ABSTRACT=<sec><title>Objective</title><p>This study aimed to explore the associations of genetic variants in the semaphorin 3A (SEMA3A) signaling pathway genes, including <italic>SEMA3A</italic>, <italic>NRP1</italic>, <italic>PLXNA1</italic>, <italic>PLXNA2</italic> and <italic>PLXNA3</italic> with osteoporosis (OP) risk and bone mineral density (BMD) in a Chinese Han older adult population.</p></sec><sec><title>Study design and method</title><p>A two-stage design was adopted. Total of 47.8kb regions in the 5 genes were sequenced using targeted next-generation sequencing (NGS) technology in the discovery stage, and the discovered OP-related single nucleotide polymorphisms (SNPs) were further genotyped using improved multiple linkage detection reaction technique in the validation stage. Methods of ALP/TRAP staining, real-time fluorescent quantitative PCR, and cell proliferation and apoptosis assays were performed with MC3T3-E1 and RAW 264.7 cell lines to clarify biological effects of observed functional variants in cell lines responsible for bone mass remodeling.</p></sec><sec><title>Results</title><p>Total of 400 postmenopausal women (211 OP cases) were involved in the discovery stage, where 6 common and 4 rare genetic variants were found to be associated with OP risk. In the validation stage among another 859 participants (417 women, 270 OP cases), the <italic>PLXNA2</italic> rs2274446 T allele was associated with reduced OP risk and increased femoral neck (FN) BMD compared to the C allele. Moreover, significant associations of <italic>NRP1</italic> rs2070296 with FN BMD/OP risk and of <italic>NRP1</italic> rs180868035 with lumbar spine and FN BMDs were also observed in the combination dataset analysis. Compared to the osteoblasts/osteoclasts transfected with the wild-type <italic>NRP1</italic> rs180868035, those transfected with the mutant-type had reduced mRNA expression of osteoblastic genes (i.e., <italic>ALP, RUNX2</italic>, <italic>SP7</italic> and <italic>OCN</italic>), while elevated mRNA expression of osteoclastic genes (i.e., <italic>TRAP</italic>, <italic>NFATc1</italic> and <italic>CTSK</italic>). Furthermore, mutant <italic>NRP1</italic> rs180868035 transfection inhibited osteoblast proliferation and osteoclast apoptosis, while promoted osteoclast proliferation and osteoblast apoptosis in corresponding cell lines.</p></sec><sec><title>Conclusion</title><p>Genetic variants located in <italic>NRP1</italic> and <italic>PLXNA2</italic> genes were associated with OP risk and BMD. The <italic>NRP1</italic> rs180868035 affects bone metabolism by influencing osteoblasts and osteoclasts differentiation, proliferation and apoptosis.</p></sec>