The allostery and modification of hGHRH molecules and specific dimer produced significant fertility effect by proliferating and activating in-situ ovarian mesenchymal stem cells.

The negative coordination of growth hormone secretagogue receptor (GHS-R) and growth hormone-releasing hormone receptor (GHRH-R) involves in the repair processes of cellular injury. The allosteric U- or H-like modified GHRH dimer Grinodin and 2Y were comparatively evaluated in normal Kunming mice and hamster infertility models induced by CPA treatment. 1-3-9 µg of Grinodin or 2Y per hamster stem-cell-exhaustion model was subcutaneously administered once a week, respectively inducing 75-69-46 or 45-13-50 % of birth rates. In comparison, the similar mole of human menopausal gonadotropin (hMG) or human growth hormone (hGH) was administered once a day but caused just 25 or 20 % of birth rates. Grinodin induced more big ovarian follicles and corpora lutea than 2Y, hMG, hGH. The hMG-treated group was observed many distorted interstitial cells and more connective tissues and the hGH-treated group had few ovarian follicles. 2Y had a plasma lifetime of 21 days and higher GH release in mice, inducing lower birth rate and stronger individual specificity in reproduction as well as only promoting the proliferation of mesenchymal-stem-cells (MSCs) in the models. In comparison, Grinodin had a plasma lifetime of 30 days and much lower GH release in mice. It significantly promoted the proliferation and activation of ovarian MSCs together with the development of follicles in the models by increasing Ki67 and GHS-R expressions, and decreasing GHRH-R expression in a dose-dependent manner. However, the high GH and excessive estrogen levels in the models showed a dose-dependent reduction in fertility. Therefore, unlike 2Y, the low dose of Grinodin specifically shows low GHS-R and high GHRH-R expressions thus evades GH and estrogen release and improves functions of organs, resulting in an increase of fertility.

PC2/CPE-mediated pro-protein processing in tumor cells and its differentiated cells or tissues.

Pro-protein convertase-2 (PC2) and carboxypeptidase-E (CPE) proteins are two major members of the pro-protein convertases that involve in the maturation of protein precursor. By using PC2 activity, immunocytochemistry (ICC) and Western blot method, PC2, CPE and preproNPY protein expression levels were compared among mature retina tissue, RGC-5 cells and its differentiated cells, or brain cortex tissue, NS20Y tumor cells and its differentiated cells, or mature breast tissue, breast tumor cell RM1 and breast adenocarcinoma tissue. The experimental results indicated that the differentiated cells or tissues had higher or highest PC2 activity. In the comparative experiments, more PC2 protein expression in the mature tissues and more CPE and preproNPY protein expression in the tumor cells or tumor tissue were observed, but no expression of preproNPY protein was observed in the mature tissues. Compared with NS20Y or RGC-5 undifferentiated cells, its differentiated cells showed less proPC2, more proCPE and more preproNPY protein expressions. The results demonstrated that the mature tissues showed stronger PC2/CPE-mediated pro-protein processing ability than the tumor cells or tissue. The results also showed that the artificial differentiation of RGC-5 or NS20Y cells was different from maturation of its corresponding normal tissue.

A novel hGHRH analog and its comparative activity.

Growth hormone releasing hormone is one of the hormones secreted from the hypothalamus. Because of its potential applications in agriculture and medicine, its short half-life and its expensive chemical synthesis, an analog with high GHRH activity and prolonged half-life was sought after. The fusion partner gene with 127 amino acid residues of the C-terminus from L-asparaginase was recombined with asp-pro-hGHRH(1-44) gene synthesized by PCR method to form one kind of fusion protein with unique acid labile linker Asp-Pro. The Pro-hGHRH(1-44) peptide was purified to homogeneity by means of cell disruption, washing, ethanol precipitation, acid hydrolysis, SP-Sephadex C-25, and Sephadex G-10 column chromatography. The peptide's molecular weight of 5,139 Da as measured by EIS-MS was coincident with the actual values. In the study of the activity, the doses of peptide were 0.1, 1.0, and 10 microg/ml for rat pituitary and 5 microg/ml for human pituitary. The peptide increased GH releases from rat pituitary in a concentration-dependent manner (P<0.05; P<0.01). At 1.0 microg/ml, there was a significant difference between Pro-Pro-hGHRH(1-44)-Gly-Gly-Cys and Pro-hGHRH(1-44) or Pro-Pro-hGHRH(1-44) (P<0.05), whereas the standard hGHRH(1-40) showed no measured rGH release. For human fetal pituitary, the Pro-hGHRH(1-44) peptides showed good GH-releasing activity, but there were no significant differences between them. The structure-activity relationship showed that for both rat and human fetal pituitary, the net GH-releasing activity of the Pro-hGHRH(1-44) analog was more than that of Pro-Pro-hGHRH(1-44). The results of the other hormones from human pituitary showed that the analog had good function-selectivity and species specificity.