The Dio3 Knockout H9c2(2-1) Polyclonal Cells are a CRISPR/Cas9-edited polyclonal population derived from the H9c2(2-1) rat embryonic ventricular cardiomyocyte line, in which targeted disruption of the Dio3 gene has been introduced. This heterogeneous cell mixture is designed for studying the consequences of Dio3 loss-of-function on thyroid hormone signaling in a cardiomyocyte background.
The H9c2(2-1) subclone, isolated from Rattus norvegicus embryonic ventricular myocardium, exhibits a contractile phenotype and serves as a widely used model for cardiac muscle cell biology. This cell line retains key features of primary cardiomyocytes, making it suitable for investigating cardiac gene regulation, hypertrophy, and metabolic processes.
The Dio3 gene encodes type 3 iodothyronine deiodinase, a selenoenzyme responsible for the inner ring deiodination and irreversible inactivation of the prohormone T4 and the active hormone T3. This catalytic function is essential for limiting local thyroid hormone bioavailability. Dio3 expression is positively regulated by T3, Sonic hedgehog, and TGF-??, and is also responsive to various growth factors and developmental morphogens. In the knockout population, disruption of Dio3 abolishes this inactivation step, leading to augmented intracellular T3 levels. Elevated T3 enhances thyroid hormone receptor (THRA/THRB) transcriptional activity at thyroid response elements (TREs) in cooperation with retinoid X receptor (RXR), thereby upregulating T3-responsive genes such as Myh6 (??-myosin heavy chain), Myh7 (??-myosin heavy chain), and Serca2a (sarcoplasmic/endoplasmic reticulum calcium ATPase 2a). Dio3 function is closely coupled to redox homeostasis through its utilization of thioredoxin and glutathione as cofactors. Key pathway components surrounding Dio3 include TSHR, T4, T3, DIO2, THRA, THRB, RXR, and TREs, forming a coordinated network that governs cardiac gene expression and metabolism.
In H9c2(2-1) cardiomyocytes, Dio3 knockout exacerbates T3-driven signaling, which can amplify hypertrophic cascades mediated by MAPK/ERK and PI3K/Akt pathways, and reprogram cardiac energy metabolism by reducing AMPK activation and fatty acid oxidation. This model is therefore valuable for dissecting the role of local thyroid hormone action in the development of cardiac hypertrophy, thyroid hormone resistance, and metabolic syndrome. Moreover, because Dio3 is often dysregulated in cancer metabolism and metabolic syndrome, this cardiomyocyte knockout system provides insights into the cardiac-specific consequences of altered deiodinase activity.
Typical applications include investigation of thyroid hormone-dependent gene expression changes via RT-qPCR and RNA-seq, assessment of hypertrophic responses through cell size measurement and immunofluorescence for cardiac markers such as troponin T, and functional analyses using luciferase reporter assays with TREs and metabolic flux analysis to monitor glycolysis and fatty acid oxidation. Researchers can also use western blotting to confirm Dio3 protein loss and cAMP assays to evaluate signaling cross-talk. The polyclonal population is useful for drug screening to identify modulators of thyroid hormone signaling in the heart. For further technical details or inquiries about this product, please contact Ascent Research.
