Humanin peptides as novel cytoprotective factors in ovarian cells

MARVALDI CAROLINA; PIDRE MATIAS LUIS; SEILICOVICH ADRIANA; MARTIN DANIEL; IMSEN MERCEDES; JAITA GABRIELA; GOTTARDO MARÍA FLORENCIA; ROMANOWSKI VÍCTOR

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Humanin (HN) peptides have cytoprotective action in several celltypes such as neurons, spermatogonias and Leydig cells. Our previ-ous results showed that HN peptides are expressed in normal ovar-ian cells, being localized in granulose cells, theca cells and oocytes.Also, we observed that HN is expressed in the human granulosa-liketumor cell line (KGN). In addition, we showed that HN increases theviability of KGN cells. The aim of present study was to explore thefunction of HN peptides in the ovary from adult rats and KGN cells.To evaluate the effect of endogenous HN, we used a baculovirusencoding a shRNA to inhibit HN expression (BV shHN). We inject-ed BV shHN and control baculovirus (BV control) into the ovarianbursa of adult rats. In ovarian sections stained with hematoxylin-eo-sin, we observed that BV shHN injection reduced the cortex areawhereas increased the stroma area. The inhibition of HN expres-sion increased the percentage of atretic follicles (BV control: 15%;BV shRNA: 78%, p < 0.01, c2). In addition, we studied the effectof silencing HN expression on the apoptosis in follicles by TUNEL.BV shRNA increased the percentage of follicles with apoptosis (BVcontrol: 11%; BV shHN: 31%, p < 0.01, c2). Also, to evaluate thefunction of endogenous HN in KGN cells, they were transduced withBV shHN or BV control. The inhibition of HN expression changedthe morphology of KGN cells, which become elongated and fibro-blast-like, and increased the percentage of apoptosis of KGN cells(BV control: 0.3%; BV shRNA: 4%, p < 0.01, c2). Considering thatthe inhibition of endogenous HN modifies the morphology of KGNcells, the architecture of the ovary and increases the percentage ofapoptotic KGN cells and follicles with apoptosis, our results suggestthat HN peptides exert a cytoprotective action in normal and tumorovarian cells. HN arises as a novel cytoprotective factor that couldplay a role in ovarian physiology and pathology.Keywords: ovary, humanin, follicle, KGN, baculovirus