2 Intrafollicular injection of asprosin in water buffaloes and the potential role of FBN1 mRNA and asprosin in follicular function

Fibrillin-1 (FBN1) functions as a structural protein in the ovary, whereas the role of its protein product asprosin remains unknown. Both proteins are encoded by the FBN1 gene; when it is cleaved at the C-terminal end, asprosin is produced. Asprosin acts as an orexigenic hormone and is associated with various metabolic parameters and sex related hormones in women. One goal of this research was to quantify FBN1 and the presumed asprosin receptor, olfactory receptor family 4 subfamily M member 1 (OR4M1) mRNA in water buffalo granulosa cells (GC) and correlate them to aromatase (CYP19A1) gene expression. A second goal was to determine the effect of asprosin on follicular growth invivo. In Experiment 1, ovaries were collected from a local slaughterhouse, GC from small (<6mm) and large (6–13mm) follicles were aspirated, RNA was extracted, and gene expression analysis conducted. In Experiment 2, an intrafollicular injection of asprosin (6μL of asprosin in 194μL of phosphate-buffered saline; to achieve 20ng mL−1) or vehicle (200μL of phosphate-buffered saline; Controls) was given via the ovarian stroma below the dominant follicle of synchronized cows (n=5/group) 1 day after injection of prostaglandin F2α, and follicle sizes were measured daily via transrectal ultrasonography until the day of ovulation. Means were compared using t-test for gene expression analysis, and Pearson correlation coefficients calculated among FBN1, OR4M1, and CYP19A1 gene expression. A repeated-measures ANOVA was used to determine the effect of asprosin on follicle size and growth rate of follicles. In Experiment 1, FBN1 mRNA abundance was 7.51-fold greater in GC of small than large follicles (P<0.05). There was no significant difference in the OR4M1 (57.83±39.89 vs. 38.98±4.86) or CYP19A1 (11.46±3.72 vs. 8.27±4.81) mRNA abundance between the 2 sizes of follicles (P>0.10). Abundance of CYP19A1 mRNA was positively correlated with FBN1 (r=0.55, P<0.05) and OR4M1 mRNA (r=0.50, P<0.05). In Experiment 2, there was a treatment×day interaction (P<0.10) for follicle size and growth rate of follicles. Cows treated with asprosin had a higher growth rate from Day 1 to 2 (1.09±0.39 to 2.37±0.32 mm/day) than placebo cows (1.74±0.55 to 1.05±0.61 mm/day) after injection. Most of the follicles from both treatment groups ovulated 3 days post injection. These findings suggest that FBN1 (and thus asprosin) are present in buffalo GC and may be developmentally expressed. Also, asprosin may induce follicular growth when given invivo. Whether these proteins directly regulate aromatase expression, and therefore oestradiol production, during follicle development will require further study.

Nucleoside transporters, bcl-2 and apoptosis in CLL cells exposed to nucleoside analogues in vitro

The purine nucleoside analogues fludarabine (F1) and chlorodeoxyadenosine (2-CdA) are considered to be cell cycle specific agents which require DNA synthesis for cytotoxicity. However, their efficacy in the treatment of CLL, an indolent lymphoid malignancy suggests additional mechanisms of action. Like cytosine arabinoside (AraC), F1 and 2-CdA gain access to the cell via a specific nucleoside transporter (NST) protein. To investigate the mode of action of these drugs in CLL, we used a fluorescent ligand for the NST (5'-(SAENTA- x8)-fluorescein) and 3-colour flow cytometry to determine NST expression on CD5+/CD19+ B-cells from the peripheral blood (PB) of patients with CLL. NST levels on these cells was found to be not significantly different from normal control lymphocytes (mean = 485 +/- 425) vs. (mean = 553 +/- 178). Exposure to varying concentrations (0, 3 microM and 30 microM) of F1 and 2-CdA, however, resulted in an upregulation of NST (mean = 1552 +/- 775 with 30 microM FL; mean = 3392 +/- 2197 with 30 microM 2-CdA) after 48. "Large" lymphoid cells (not present in normal PB) were found to express significantly more NST (mean = 2540 +/- 2861) and have a higher proliferative capacity than "small" cells (mean = 357 +/- 517 NST/cell). Incubation of CLL cells with F1 (n = 6) and 2-CdA (n = 8) in vitro over 48 h also resulted in an increase in the proportion of cells in S-phase (0 microM = 0.2 + 2 - 0.1; 30 microM FL = 2.4 +/- 2.0; 30 microM 2-CdA = 3.3 +/- 1.3) and a significant increase in morphologically identifiable apoptosis. Apoptosis was confirmed by flow cytometric DNA analysis (0 microM = 13 +/- 8%; 30 microM FL = 40 +/- 20%; 30 microM 2-CdA = 48 +/- 11%). In situ hybridization using a biotinylated cDNA bcl-2 probe demonstrated that bcl-2 mRNA expression was markedly decreased in treated cells after 24 h. These studies have demonstrated that: (1) NST expression on CLL lymphocytes is low; (2) in vitro exposure to the analogues increases both the level of NST expression and the % cells in S-phase; (3) exposure to the analogues downregulates bcl-2 expression and increases apoptosis.