Protein modulation in mouse heart under acute and chronic hypoxia

Exploring cellular mechanisms underlying beneficial and detrimental responses to hypoxia represents the object of the present study. Signaling molecules controlling adaptation to hypoxia (HIF-1a), energy balance (AMPK), mitochondrial biogenesis (PGC-1a), autophagic/ apoptotic processes regulation and proteomic dysregulation were assessed. Responses to acute hypoxia (AH) and chronic hypoxia (CH) in mouse heart proteome were detected by 2-D DIGE, mass spectrometry and antigen–antibody reactions. Both in AH and CH, the results indicated a deregulation of proteins related to sarcomere stabilization and muscle contraction. Neither in AH nor in CH the HIF-1a stabilization was observed. In AH, the metabolic adaptation to lack of oxygen was controlled by AMPK activation and sustained by an upregulation of adenosylhomocysteinase and acetyl-CoA synthetase. AH was characterized by the mitophagic protein Bnip 3 increment. PGC-1a, a master regulator of mitochondrial biogenesis, was down-regulated. CH was characterized by the up-regulation of enzymes involved in antioxidant defense, in aldehyde bio-product detoxification and in misfolded protein degradation. In addition, a general down-regulation of enzymes controlling anaerobic metabolism was observed. After 10 days of hypoxia, cardioprotective molecules were substantially decreased whereas pro-apoptotic molecules increased accompained by downregulation of specific target proteins.