Hif1α Mediated Ho-1 Expression in Fish Adipocytes: Role of Hypoxia In Ennore Estuary

Abstract

Heme oxygenase-1 (HO-1), an inducible stress protein; is involved in the regulation of adipogenesis, cellular bioenergetics and cytoprotective mechanism against hypoxia induced oxidative stress. Polluted aquatic environment leads to large oxygen fluctuations which may cause alteration in fish adaptation mechanism by HIF1α regulation. Environmental pollutants have a high tendency to accumulate, persist and bio-concentrate in adipocytes due to its lipophilic nature which ultimately causes adipocytes hypoxia that in turn affects metabolic energy balance. CYP1A2 and HO-1 are the chief detoxifying and cytoprotective enzymes involved in the oxidative metabolism of a wide variety of pollutants and its mediated cytotoxic products. The key role of hypoxia and its mediated signaling protein changes in fish adipocytes due to low dissolved oxygen in Ennore estuary was demonstrated in our previous work. Therefore, we analyzed the effect of pollutants induced hypoxia by assessing CD, HNE, TAC, G3PDH, ATP, HIF1α, HO-1 and CYP1A2 in fish adipocytes of control/unpolluted site and test/polluted site. Increase in CD, HNE, HIF1α, HO-1 along with a decrease in TAC, G3PDH, ATP and CYP1A2 observed in test adipocytes. From the results achieved, it shows that induction of HO-1 by HIF1α is crucial in maintaining the cell integrity to secure adipocytes and its maturation in the fish collected from the hypoxic environment. This study also highlights the role of HIF1α and HO-1 in regulating the expression of CYP1A2 during pollutants induced hypoxic condition.