Kathleen C Woulfe1, Danielle A Jeffrey1, Julie Pires Da Silva1, Cortney E Wilson1, Jennifer H Mahaffey1, Edward Lau1, Dobromir Slavov1, Frehiwet Hailu1, Anis Karimpour-Fard2, Karen Dockstader1, Michael R Bristow1, Brian L Stauffer3, Shelley D Miyamoto4, Carmen C Sucharov5. 1. Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States. 2. Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States. 3. Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States; Denver Health Medical Center, Denver, CO, United States. 4. Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital of Colorado, Aurora, CO, United States. 5. Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States. Electronic address: kika.sucharov@cuanschutz.edu.
Abstract
AIMS: Pediatric dilated cardiomyopathy (pDCM) is characterized by unique age-dependent molecular mechanisms that include myocellular responses to therapy. We previously showed that pDCM, but not adult DCM patients respond to phosphodiesterase 3 inhibitors (PDE3i) by increasing levels of the second messenger cAMP and consequent phosphorylation of phospholamban (PLN). However, the molecular mechanisms involved in the differential pediatric and adult response to PDE3i are not clear. METHODS AND RESULTS: Quantification of serum response factor (SRF) isoforms from the left ventricle of explanted hearts showed that PDE3i treatment affects expression of SRF isoforms in pDCM hearts. An SRF isoform lacking exon 5 (SRFdel5) was highly expressed in the hearts of pediatric, but not adult DCM patients treated with PDE3i. To determine the functional consequence of expression of SRFdel5, we overexpressed full length SRF or SRFdel5 in cultured cardiomyocytes with and without adrenergic stimulation. Compared to a control adenovirus, expression of SRFdel5 increased phosphorylation of PLN, negatively affected expression of the phosphatase that promotes dephosphorylation of PLN (PP2Cε), and promoted faster calcium reuptake, whereas expression of full length SRF attenuated calcium reuptake through blunted phosphorylation of PLN. CONCLUSIONS: Taken together, these data indicate that expression of SRFdel5 in pDCM hearts in response to PDE3i contributes to improved function through regulating PLN phosphorylation and thereby calcium reuptake.
AIMS: Pediatric dilated cardiomyopathy (pDCM) is characterized by unique age-dependent molecular mechanisms that include myocellular responses to therapy. We previously showed that pDCM, but not adult DCM patients respond to phosphodiesterase 3 inhibitors (PDE3i) by increasing levels of the second messenger cAMP and consequent phosphorylation of phospholamban (PLN). However, the molecular mechanisms involved in the differential pediatric and adult response to PDE3i are not clear. METHODS AND RESULTS: Quantification of serum response factor (SRF) isoforms from the left ventricle of explanted hearts showed that PDE3i treatment affects expression of SRF isoforms in pDCM hearts. An SRF isoform lacking exon 5 (SRFdel5) was highly expressed in the hearts of pediatric, but not adult DCM patients treated with PDE3i. To determine the functional consequence of expression of SRFdel5, we overexpressed full length SRF or SRFdel5 in cultured cardiomyocytes with and without adrenergic stimulation. Compared to a control adenovirus, expression of SRFdel5 increased phosphorylation of PLN, negatively affected expression of the phosphatase that promotes dephosphorylation of PLN (PP2Cε), and promoted faster calcium reuptake, whereas expression of full length SRF attenuated calcium reuptake through blunted phosphorylation of PLN. CONCLUSIONS: Taken together, these data indicate that expression of SRFdel5 in pDCM hearts in response to PDE3i contributes to improved function through regulating PLN phosphorylation and thereby calcium reuptake.
Authors: Amit Etkin; Juan Marcos Alarcón; Stuart P Weisberg; Khalid Touzani; Yan You Huang; Alfred Nordheim; Eric R Kandel Journal: Neuron Date: 2006-04-06 Impact factor: 17.173
Authors: Stephanie J Nakano; Shelley D Miyamoto; Matthew Movsesian; Penny Nelson; Brian L Stauffer; Carmen C Sucharov Journal: Circ Heart Fail Date: 2014-10-02 Impact factor: 8.790
Authors: Philip D Tatman; Kathleen C Woulfe; Anis Karimpour-Fard; Danielle A Jeffrey; James Jaggers; Joseph C Cleveland; Karin Nunley; Matthew Rg Taylor; Shelley D Miyamoto; Brian L Stauffer; Carmen C Sucharov Journal: JCI Insight Date: 2017-07-20