Endocrine Abstracts

To maintain proper fertility the balance between formation and luteolysis of corpus luteum (CL) are necessary and strictly controlled events in female reproduction. Degeneration of CL is correlated with apoptosis and autophagy as well as connected with decreased progesterone (P4) level. Resistin is a new key player in the regulation of luteal cells function; our previously study showed that resistin have negative effect on P4 synthesis. Thus the aim of the present study was to investigate the effect of resistin on proliferation, apoptosis, and autophagy of porcine luteal cells and involvement of mitogen-activated kinase (MAP3/1), protein kinase B (AKT), and signal transducer and activator of transcription 3 (STAT3) in these processes. Porcine luteal cells at the middle luteal phase were incubated with resistin (0.1-10 ng/ml) for 24 h to 72 h and cells proliferation was assessed by alamarBlue or MTT assay. Then, the time-dependent (24 h to 72 h) effect of resistin (1 ng/ml) on the transcript and protein level of proliferation: proliferating cells nuclear antigen (PCNA), apoptosis: caspase 3, BCL2-like protein 4 (BAX), B-cell lymphoma (BCL2), and autophagy: beclin1, microtubule-associated protein 1A/1B-light chain 3 (LC3), lysosomal-associated membrane protein 1 (LAMP1) markers were measured by real-time PCR and Western blot, respectively. We noted that resistin stimulated luteal cell proliferation with no effect on caspase 3, increased BAX/BCL2 ratio and enhanced the initiation of autophagy, which promotes the maintenance of luteal function rather than its luteolysis. Besides, using pharmacological blockers of MAP3/1 (PD98059), AKT (LY294002), and STAT3 (AG490) we observed that the effect of resistin was downregulated to the control level in proliferation and by activation MAP3/1 and STAT3 in autophagy. Summarizing, our results indicated that resistin is a new regulator of female reproduction by direct effect on CL regression, formation and maintenance of luteal cell function. It may be a future therapeutic target in luteal cells deficiency treatment leading to enhanced numbers of healthy pregnancies. However, in vivo experiments are necessary to confirm this hypothesis. Funding: The publication was co-financed by the Foundation of Students and Graduates of the Jagiellonian University ‘Bratniak’.