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Cellular localization of integrin isoforms in phenylephrine‐induced hypertrophic cardiac myocytes
Author(s) -
Kim Dae Joong,
Park Sang Hee,
Lim Chol Seung,
Chun JangSoo,
Kim JinKyu,
Song Woo Keun
Publication year - 2003
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.988
Subject(s) - fibronectin , myocyte , integrin , extracellular matrix , muscle hypertrophy , microbiology and biotechnology , cardiac myocyte , medicine , endocrinology , chemistry , biology , receptor
Cardiac hypertrophy is characterized by remodeling of the extracellular matrix (ECM). Integrins are cell‐surface molecules that link the ECM to the cellular cytoskeleton where they play roles as signaling molecules and transducers of mechanical force. To clarify the possible roles of integrins in cardiac myocyte hypertrophy, we investigated the cellular localization and expression of ECM proteins and integrins in both normal cardiac myocytes and phenylephrine‐induced hypertrophic myocytes. Addition of phenylephrine (PE) to cultured neonatal cardiac myocytes induced sarcomeric organization, increase in cell size, and synthesis of the hypertrophic marker, atrial natriuretic factor (ANF). In particular, fibronectin and collagen underwent dramatic localization changes during PE‐induced cardiac hypertrophy. Significant changes were noted in the cellular localization of the respective collagen and fibronectin receptors, integrin α1 and α5, from diffuse to a sarcomeric banding pattern. Expression levels of integrins were also increased during hypertrophy. Treatment with okadaic acid (OA), an inhibitor of protein phosphatase 2A (PP2A), resulted in inhibition of hypertrophic response. These results suggest that dephosphorylation of integrin β1 may be important in the induction of cardiac hypertrophy. Copyright © 2002 John Wiley & Sons, Ltd.