Rabbit Anti-Human FYN (Phospho-Tyr213) polyclonal antibody

The mechanism for intermittent hypoxia (IH)-induced cardiomyopathy remains obscure. We reported the prevention of acute and chronic IH-induced cardiac damage by selective cardiac overexpression of metallothionein (MT). Herein we defined that MT-mediated protection from IH-cardiomyopathy is via activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a critical redox-balance controller in the body. For this, mice were exposed to IH for 3 days (acute) or 4 or 8 weeks (chronic). Cardiac Nrf2 and MT expression in response to IH were significantly increased acutely yet decreased chronically. Interestingly, cardiac overexpression (Nrf2-TG) or global deletion of the Nrf2 gene (Nrf2-KO) made mice highly resistant or highly susceptible, respectively, to IH-induced cardiomyopathy and MT expression. Mechanistically, 4-week IH exposure significantly decreased cardiac Nrf2 binding to the MT gene promoter, and thus, depressed both MT transcription and translation in WT mice but not Nrf2-TG mice. Likewise, cardiac MT overexpression prevented chronic IH-induced cardiomyopathy and down-regulation of Nrf2 likely via activation of a PI3K/Akt/GSK-3 beta/Fyn-dependent signaling pathway. These results reveal an integrated relationship between cardiac Nrf2 and MT expression in response to IH - acute compensatory up-regulation followed by chronic down-regulation and cardiomyopathy. Cardiac overexpression of either Nrf2 or MT offered cardioprotection from IH via complicated PI3K/Akt/GSK3B/Fyn signaling. Potential therapeutics may target either Nrf2 or MT to prevent chronic IH-induced cardiomyopathy.

Sulforaphane (SFN) prevents diabetic nephropathy (DN) in type 2 diabetes (T2D) by up-regulating nuclear factor (erythroid-derived 2)-like 2 (Nrf2). AMP-activated protein kinase (AMPK) can attenuate the pathogenesis of DN by improving renal lipotoxicity along with the activation of Nrf2-mediated antioxidative signaling. Therefore, we investigated whether AMPK alpha 2, the central subunit of AMPK in energy metabolism, is required for SFN protec-tion against DN in T2D, and whether potential cross-talk occurs between AMPK alpha 2 and Nrf2. AMPK alpha 2 knockout (Ampk alpha 2(-/-)) mice and wildtype (WT) mice were fed a high-fat diet (HFD) or a normal diet (ND) to induce insulin resistance, followed by streptozotocin (STZ) injection to induce hyperglycemia, as a T2D model. Both T2D and control mice were treated with SFN or vehicle for 3 months. At the end of the 3-month treatment, all mice were maintained only on HFD or ND for an additional 3 months without SFN treatment. Mice were killed at sixth month after T2D onset. Twenty-four-hour urine albumin at third and sixth months was significantly increased as renal dysfunction, along with significant renal pathological changes and biochemical changes including renal hypertrophy, oxidative damage, inflammation, and fibrosis in WT T2D mice, which were prevented by SFN in certain contexts, but not in Ampk alpha 2(-/-) T2D mice. SFN prevention of T2D-induced renal lipotoxicity was associated with AMPK-mediated activation of lipid metabolism and Nrf2-dependent antioxidative function in WT mice, but not in SFN-treated Ampk alpha 2(-/-) mice. Therefore, SFN prevention of DN is AMPK alpha 2-mediated activation of probably both lipid metabolism and Nrf2 via AMPK/AKT/glycogen synthase kinase (GSK)-3 beta/Src family tyrosine kinase (Fyn) pathways.