Is Humanin a cytoprotective factor against oxidative stress in ovarian cells?

M.IRIZARRI; M.IMSEN; D.MARTIN; A. SEILICOVICH; C.MARVALDI; G. JAITA

Congreso; LXIII Reunión de la Sociedad Argentina de Investigación Clínica; 2018

Humanin (HN) exerts cytoprotection against oxidative stress in cardiac, retinal and pancreatic cells. Previously, we reported that inhibition of endogenous HN in a human granulosa-like tumor cell line (KGN) increases apoptosis and that exogenous HN increases viability of KGN cells. In this study, we aimed to evaluate the action of HN against oxidative stress in ovarian cells. We analyzed the effect of HN on ROS production in cultured KGN cells using a fluorescence indicator (DCF). We incubated KGN cells with DCF (10 µM) for 30 min and HN (1µM) for further 30 min. Afterward, KGN cells were exposed to H2O2 (150 µM) and we analyzed DCF fluorescence. HN per se did not modify ROS production (C: 1689.6 ± 17.5; HN: 1677.6 ± 10.3, ns) but decreased ROS in cultured KGN incubated with H2O2 (H2O2: 2157.3 ± 49.1; H2O2+HN: 1929.3 ± 47.5, p < 0.05, Student?s t test). Also, we explored the expression and function of HN in Chinese hamster ovary (CHO) cells. We observed that CHO cells express HN by immunofluorescence. Considering that serum withdrawal may induce oxidative stress, we evaluated the action of HN in CHO cells in this condition. HN did not modify CHO cell viability in the presence of serum (C: 1.07 ± 0.04, HN 0.25 µM: 1.09 ± 0.05, HN 0.5 µM: 1.12 ± 0.05, HN 1 µM: 1.12 ± 0.02, ns). However, HN increased CHO cell viability in the absence of serum (C: 0.81 ± 0.04, HN 0.25 µM: 1.00 ± 0.06, HN 0.5 µM: 1.03 ± 0.02, HN 1µM: 0.95 ± 0.06, p < 0.05. ANOVA). Since in a pro-oxidative environment HN increases CHO cell viability and decreases ROS in KGN cells, our results suggest that HN could play a cytoprotective role against oxidative stress in ovarian cells.