Modulation of ASK1 expression during overexpression of Trx and HSP70 in stressed fish liver mitochondria

Abstract

Mitochondrial heat shock protein 70 (mtHSP70) is found to play a primary role in cellular defense against physiological stress like exposure to environmental contaminants and helpful in the maintenance of cellular homeostasis by promoting the cell survival. In the present investigation, the environmental-stress-induced increase in mtHSP70 levels along with the quantification of apoptosis signal regulating kinase 1 (ASK1) and thioredoxin (Trx) were measured in the liver mitochondria of grey mullets (Mugil cephalus) collected from the polluted Ennore estuary and the unpolluted Kovalam estuary for a period of 2 years. The results showed elevated lipid peroxide (LPO) and decreased total antioxidant capacity along with the decrease in mitochondrial viability percentage. Mitochondrial HSP70, ASK1, and Trx levels were increased under this stress condition. A 42% increase in LPO levels and 18% decrease in mitochondrial survivality were observed in the polluted-site fish liver mitochondria when compared to the results of unpolluted estuary. We also report that, under observed oxidative stress condition in Ennore fish samples, the ASK1 levels are only moderately elevated (13% increase). This may be due to mitochondrial-HSP70-induced adaptive tolerance signaling for the activation of Trx (22% increase) which suppresses the ASK1 expression thereby promoting the cell survival that leads to the maintenance of the cellular homeostasis.

Identification and molecular analysis of a stress-inducible Hsp70 from Sciaenops ocellatus

“…For example, Cu, Cd, Pb, and Zn were found to induce the expression of hsp70 in fathead minnow, yellow perch, and rainbow trout [51e54]; arsenite and the herbicide oxyfluoren are known to stimulate hsp70 expression in salmon and the Egyptian Nile fish [55,56]. In addition, oxidative stress has also been found to affect hsp70 expression in some fish species [57,58]. In our study, we found that SoHsp70 expression was significantly upregulated by challenges with Fe, Cu, Hg, and H 2 O 2 .…”

Does Predation Exacerbate the Risk of Endosymbiont Loss in Heat Stressed Hermatypic Corals? Molecular Cues Provide Insights Into Species-Specific Health Outcomes in a Multi-Stressor Ocean

“…Stress biomarkers heat shock protein 70 kDa (Hsp70), total ubiquitin (Ub), and total antioxidant capacity (TAC) were then quantified. These biomarkers were selected due to their important roles in cellular stress responses of organisms to environmental challenges and thermal adaptation: (i) Hsp70 is a chaperone that stabilizes degrading proteins ( Jolly et al, 2018 ); (ii) Ub signals irreversibly damaged proteins for degradation in the proteasome ( Madeira et al, 2014 ) and TAC quantifies both enzymatic and non-enzymatic antioxidants, which indicates the ability to counteract oxidative stress-induced damage in cells ( Padmini and Geetha, 2009 ).…”

Cynoglossus semilaevis thioredoxin: a reductase and an antioxidant with immunostimulatory property

“…For example, treatment of monocytes, fibrosarcoma, and endothelial cells with Trx1 induced the expression of TNF, IL-1, IL-6, IL-2, and IL-8 (Schenk et al 1996;Padmini and Rani 2010). In teleost, immune-regulatory property has only been found in the Trx of flathead mullet, which modulates the activity of apoptosis signal-regulating kinase 1 and cJun NH2-terminal kinase 1/2 (Takeda et al 2003;Padmini and Vijaya Geetha 2009). In our study, we examined whether rCsTrx1 had any effect on the expression of the immune genes that so far have been identified in tongue sole.…”