Anti-HSPA5 monoclonal antibody, clone 87-F7

PurposeThe aim of this study was undertaken to investigate the association of 78-kDa glucose-regulated protein (GRP78) gene promoter polymorphisms with risk of asthenozoospermia (AZS) men. In addition, we performed association analysis between GRP78 promoter mutations and serum GRP78 level in asthenozoospermia.MethodsThe study population comprised 400 subjects with AZS patients and 400 healthy controls. We assessed GRP78 rs3216733, rs17840761, and rs17840762 polymorphisms by using Snapshot SNP genotyping assays; serum GRP78 level was measured by enzyme-linked immunosorbent assay (ELISA). Semen quality was assessed by computer-assisted semen analysis.ResultsWe found that rs3216733 was associated with increased risk of AZS (Gd vs. dd: adjusted OR=1.42, 95% CI, 1.06-1.93, P=0.020; Gd/GG vs. dd: adjusted OR=1.43, 95% CI, 1.08-1.91, P=0.013; G vs. d adjusted OR=1.26, 95% CI, 1.03-1.56, P=0.027). The haplotype analyses showed the frequency of G-C-C haplotype was significantly higher in AZS (P=0.026). The percentage of progressive motility sperm was lower in the asthenozoospermic men with Gd and Gd/GG genotypes than dd genotype (P=0.003). Moreover, the serum GRP78 levels were significantly lower in rs3216733 Gd/GG genotypes compared with the dd genotype (P<0.001).ConclusionOur findings suggest that rs3216733 Gd/GG genotypes contribute to poor sperm motility, probably by decreasing the level of GRP78.

The endoplasmic reticulum (ER) is an important site for protein folding and becomes "stressed" when its capacity to fold proteins is overwhelmed. In response, "unfolded protein response" (UPR) genes are induced, increasing the capacity to fold proteins; if the response is insufficient, then apoptosis ensues. For investigation of whether proteinuria and hyperglycemia induce ER stress in renal epithelial cells, microarray data from biopsies of established diabetic nephropathy (DN) were analyzed. Expression of UPR genes was significantly different in these biopsies than in control kidneys or biopsies of patients with mild DN, suggesting an association between the degree of DN and UPR gene expression. Expression of the transcription factor XBP1 and the ER chaperones HSPA5 and HYOU1 were increased, but the proapoptotic gene DDIT3 was unchanged. These findings were replicated in an independent cohort of patients with established DN by real-time reverse transcriptase-PCR. Immunofluorescence of renal biopsies from patients with DN confirmed the upregulation for HSPA5 and HYOU1 proteins in tubular epithelia. In biopsies of minimal-change disease, the mRNA levels of some ER stress molecules were also induced, but protein expression of HSPA5 and HYOU1 remained significantly lower than that observed in DN. Exposure of renal tubular epithelial cells to albumin and high glucose in vitro enhanced expression of genes involved in ER stress. These observations suggest that in proteinuric diseases, tubular epithelial cells undergo ER stress, which induces an adaptive, protective UPR. Although this may protect the cells from ER stress, persistence of hyperglycemia and proteinuria may eventually lead to apoptosis.