TrxR2

TrxR₂ (TXNRD2) is the mitochondrial thioredoxin reductase that maintains Trx2 in a reduced state and supports mitochondrial redox signaling^[1]. Mechanistically, the mitochondrial TrxR₂-Trx2-peroxiredoxin system uses NADPH-linked electron transfer to control peroxide and peroxynitrite burden in mitochondria and vascular endothelium^[2]. In mouse models, loss of Txnrd2 causes defective hematopoiesis, abnormal heart development, and impaired heart function, showing that TrxR₂ is essential for high-energy and redox-sensitive tissues^[3]. In aging myocardium, heart-specific Txnrd2 deletion reduces mitochondrial oxygen use, increases reactive oxygen species, and produces metabolic and contractile dysfunction^[4]. Human studies further connect TXNRD2 mutations with dilated cardiomyopathy, supporting disease relevance beyond experimental knockout systems^[5]. Compared with related isoforms, TrxR₁ localizes mainly to cytosol, TrxR₂ localizes to mitochondria, and TrxR₃ is primarily testis-associated, making mitochondrial compartment specificity the key distinction for TrxR₂-focused experiments^[6]. For experimental applications, auranofin-mediated TrxR inhibition and shRNA targeting TrxR₂ sensitized dopaminergic cells to paraquat- or 6-hydroxydopamine-induced mitochondrial dysfunction, increased H₂O₂, and cell death^[7]. Broad TrxR inhibitors can alter antioxidant defense, redox signaling, and cell survival, so TrxR₂ studies should distinguish mitochondrial target engagement from pan-isoform inhibition^[8].