Structure of GPR101-Gs enables identification of ligands with rejuvenating potential.

GPR101 is an orphan G protein-coupled receptor actively participating in energy homeostasis. Here we report the cryo-electron microscopy structure of GPR101 constitutively coupled to Gs heterotrimer, which reveals unique features of GPR101, including the interaction of extracellular loop 2 within the 7TM bundle, a hydrophobic chain packing-mediated activation mechanism and the structural basis of disease-related mutants. Importantly, a side pocket is identified in GPR101 that facilitates in silico screening to identify four small-molecule agonists, including AA-14. The structure of AA-14-GPR101-Gs provides direct evidence of the AA-14 binding at the side pocket. Functionally, AA-14 partially restores the functions of GH/IGF-1 axis and exhibits several rejuvenating effects in wild-type mice, which are abrogated in Gpr101-deficient mice. In summary, we provide a structural basis for the constitutive activity of GPR101. The structure-facilitated identification of GPR101 agonists and functional analysis suggest that targeting this orphan receptor has rejuvenating potential.

Activation of PTH1R alleviates epididymitis and orchitis through Gq and ß-arrestin-1 pathways.

Inflammation in the epididymis and testis contributes significantly to male infertility. Alternative therapeutic avenues treating epididymitis and orchitis are expected since current therapies using antibiotics have limitations associated to side effects and are commonly ineffective for inflammation due to nonbacterial causes. Here, we demonstrated that type 1 parathyroid hormone receptor (PTH1R) and its endogenous agonists, parathyroid hormone (PTH) and PTH-related protein (PTHrP), were mainly expressed in the Leydig cells of testis as well as epididymal epithelial cells. Screening the secretin family G protein-coupled receptor identified that PTH1R in the epididymis and testis was down-regulated in mumps virus (MuV)- or lipopolysaccharide (LPS)-induced inflammation. Remarkably, activation of PTH1R by abaloparatide (ABL), a Food and Drug Administration-approved treatment for postmenopausal osteoporosis, alleviated MuV- or LPS-induced inflammatory responses in both testis and epididymis and significantly improved sperm functions in both mouse model and human samples. The anti-inflammatory effects of ABL were shown to be regulated mainly through the Gq and ß-arrestin-1 pathway downstream of PTH1R as supported by the application of ABL in Gnaq± and Arrb1-/- mouse models. Taken together, our results identified an important immunoregulatory role for PTH1R signaling in the epididymis and testis. Targeting to PTH1R might have a therapeutic effect for the treatment of epididymitis and orchitis or other inflammatory disease in the male reproductive system.

Curcumin as a potent and selective inhibitor of 11ß-hydroxysteroid dehydrogenase 1: improving lipid profiles in high-fat-diet-treated rats.

BACKGROUND: 11ß-Hydroxysteroid dehydrogenase 1 (11ß-HSD1) activates glucocorticoid locally in liver and fat tissues to aggravate metabolic syndrome. 11ß-HSD1 selective inhibitor can be used to treat metabolic syndrome. Curcumin and its derivatives as selective inhibitors of 11ß-HSD1 have not been reported. METHODOLOGY: Curcumin and its 12 derivatives were tested for their potencies of inhibitory effects on human and rat 11ß-HSD1 with selectivity against 11ß-HSD2. 200 mg/kg curcumin was gavaged to adult male Sprague-Dawley rats with high-fat-diet-induced metabolic syndrome for 2 months. RESULTS AND CONCLUSIONS: Curcumin exhibited inhibitory potency against human and rat 11ß-HSD1 in intact cells with IC50 values of 2.29 and 5.79 µM, respectively, with selectivity against 11ß-HSD2 (IC50, 14.56 and 11.92 µM). Curcumin was a competitive inhibitor of human and rat 11ß-HSD1. Curcumin reduced serum glucose, cholesterol, triglyceride, low density lipoprotein levels in high-fat-diet-induced obese rats. Four curcumin derivatives had much higher potencies for Inhibition of 11ß-HSD1. One of them is (1E,4E)-1,5-bis(thiophen-2-yl) penta-1,4-dien-3-one (compound 6), which had IC50 values of 93 and 184 nM for human and rat 11ß-HSD1, respectively. Compound 6 did not inhibit human and rat kidney 11ß-HSD2 at 100 µM. In conclusion, curcumin is effective for the treatment of metabolic syndrome and four novel curcumin derivatives had high potencies for inhibition of human 11ß-HSD1 with selectivity against 11ß-HSD2.

[Association between HLA-DRB1, DQB1 genes and pemphigus vulgaris in Chinese Hans].

OBJECTIVE: To investigate the predisposing role of HLA-DRB1, DQB1 genes in pemphigus vulgaris (PV). METHODS: Polymerase chain reaction-specific sequence primers method was used to type HLA-DRB1, DQB1 subregion in the patients with PV of Han nationality from Jiangsu and Anhui provinces and matched control subjects. RESULTS: DR4, DRB1*14(*1401,*1404,*1405) gene frequencies in PV patients were significantly higher than those in controls (Pc<0.05 and Pc<0.01 respectively). DQB1*0302, DQB1*0503 gene frequencies were significantly higher in PV patients (Pc<0.05). Further typing of DR4 positive subjects revealed that the gene frequencies of DRB1*0406, *0403 were significantly increased in PV patients as compared with controls (Pc<0.05). The haplotype frequencies of HLA-DRB1*04, DQB1*0302 and HLA-DRB1*14, DQB1*0503 in PV patients were significantly higher than those in controls (P<0.05). CONCLUSION: The results suggest that the combination of HLA-DRB1*4, DQB1*0302 and HLA-DRB1*14, DQB1*0503 forms putative susceptible haplotypes for PV patients in Chinese Hans.