Thioredoxin and HSP90 alpha modulate ASK1-JNK1/2 signaling in stressed hepatocytes of Mugil cephalus.
Induction of antioxidant proteins like thioredoxin (Trx) and heat shock protein 90 alpha (HSP90 alpha) is a crucial step in the cellular response to oxidative stress. Here, we report the impact of environmental stress on Trx and HSP90 alpha expressions in freshly isolated hepatocytes of Mugil cephalus living in either a contaminated (Test; Ennore) or uncontaminated (Control; Kovalam) estuary. Modulation in the activities of signal transduction molecules like apoptosis signal-regulating kinase 1 (ASK1) and c-Jun NH(2)-terminal kinase 1/2 (JNK1/2) were also investigated to understand their functional role under natural stressed condition. The expression pattern of the proteins was determined by immunoblotting and the relationship between the proteins was identified by regression analysis. Test fish hepatocytes demonstrated significant upregulation (P<0.05) in the levels of Trx and HSP90 alpha and insignificant inductions in the expression pattern of ASK1 and JNK1/2 than control fish hepatocytes. These findings provide direct evidence that Trx and HSP90 alpha induction in fish hepatocytes under stress may aid cell survival by negatively regulating ASK1 expression and thereby functionally antagonizing the apoptotic role of JNK1/2 in natural aquatic systems.
Department of Biochemistry, Bharathi Women's College, Chennai-108, Tamilnadu, India. dstpadmini@rediffmail.com
Ekambaram
E
Padmini
Munuswamy Usha
MU
Rani
D000818:Animals; D002478:Cells, Cultured; D029941:Fish Proteins / Q000378:metabolism; D005399:Fishes / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D015151:Immunoblotting; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism; D048056:Mitogen-Activated Protein Kinase 9 / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012044:Regression Analysis; D015398:Signal Transduction; D013879:Thioredoxins / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D014873:Water Pollutants / Q000633:toxicity
D029941:Fish Proteins; D018841:HSP90 Heat-Shock Proteins; D014873:Water Pollutants; D013879:Thioredoxins; D048056:Mitogen-Activated Protein Kinase 9; D017346:Protein Serine-Threonine Kinases; D048055:Mitogen-Activated Protein Kinase 8; D048848:MAP Kinase Kinase Kinase 5