Our long term goal is to understand mechanisms that govern spatiotemporal regulation of cAMP/PKA signaling in cardiac myocytes under physiological and pathophysiological conditions, and their implication in cardiac therapy. During heart failure, down-regulation of the b adrenergic receptor (AR) takes place; however downstream alterations in the pathway, i.e. regulation of substrate phosphorylation by cAMP- dependent protein kinase A (PKA), may precede the down-regulation. The major hypothesis here is that spatiotemporal propagation of cAMP/PKA signaling controlled by bAR subtype-associated phosphodiesterase (PDE) isoforms and arrestin-dependent sequestration of PDEs provides novel mechanism on regulating cardiac response to adrenergic stimulation. We will use both functional measurement of myocyte contraction and real-time measurement of cAMP/PKA activities under bAR subtype regulation to uncover the mechanism underlying functional regulation of intracellular propagation of bAR signaling from the cell surface to intracellular compartments in cardiac myocytes.
Aim 1. To characterize the effects of subtype-specific bAR/PDE4D complexes on spatiotemporal cAMP/PKA signaling propagation in cardiac myocytes. We will characterize the association of PDE4Ds with bAR subtypes in different complexes, mechanisms of agonist-dependent dissociation of PDE4Ds from the complexes (via phosphorylation by PKA and/or GRK), and the effects of PDE4Ds on cAMP/PKA activities in different cellular compartments, substrate phosphorylation, calcium signaling, and cardiac myocyte contraction.
Aim 2. To characterize the mechanism(s) by which barrestin 1 and 2 control spatiotemporal cAMP/PKA propagation during bAR stimulation in cardiac myocytes. We will examine the association of PDE4D isoforms with bAR subtype-activated arrestins and PKA in cardiac myocytes, the differential roles of arrestin 2 and 3 in controlling bAR subtype-induced cAMP/PKA activities in different cellular compartments, substrate phosphorylation, calcium signaling, and cardiac myocyte contraction. We will also examine the interactive effects of b1 and b2AR on the spatiotemporal propagation of cAMP signaling.
Aim 3. To investigate the alteration(s) of bAR/PDE4D complexes in controlling spatiotemporal cAMP/PKA signaling propagation in cardiac myocytes from failing hearts. We will examine the integrity of bAR/PDE4D complexes in myocytes isolated from transverse aortic constriction (TAC)-induced cardiac hypertrophy and heart failure rats, and whether altered bAR association with PDE4D isoforms contributes to depressed spatiotemporal cAMP signal propagation and decreased cardiac contractile responses. We will attempt to selectively inhibit a specific PDE4D isoform by adenovirus gene transfer of PDE4D mutants into myocardium of TAC-treated animals, and examine cardiac performance in vivo.
Heart failure is the major health issue contributing one of the deadliest diseases in the United States. In this proposed study, we are asking a critical question: how beta adrenergic signaling, the major signaling system that regulates cardiac function during stresses, is altered at the early stage of heart failure? These studies will provide novel information on using other proteins as therapeutic targets in the beta adrenergic signaling pathway in treating heart failure.
|Zhao, Hongyu; Shen, Ao; Xiang, Yang K et al. (2016) Three Recombinant Engineered Antibodies against Recombinant Tags with High Affinity and Specificity. PLoS One 11:e0150125|
|Skieterska, Kamila; Shen, Ao; Clarisse, Dorien et al. (2016) Characterization of the interaction between the dopamine D4 receptor, KLHL12 and ?-arrestins. Cell Signal 28:1001-14|
|Barbagallo, Federica; Xu, Bing; Reddy, Gopireddy R et al. (2016) Genetically Encoded Biosensors Reveal PKA Hyperphosphorylation on the Myofilaments in Rabbit Heart Failure. Circ Res 119:931-43|
|Fu, Qin; Xiang, Yang K (2015) Trafficking of ?-Adrenergic Receptors: Implications in Intracellular Receptor Signaling. Prog Mol Biol Transl Sci 132:151-88|
|Fu, Qin; Xu, Bing; Parikh, Dippal et al. (2015) Insulin induces IRS2-dependent and GRK2-mediated ?2AR internalization to attenuate ?AR signaling in cardiomyocytes. Cell Signal 27:707-15|
|Fu, Qin; Xu, Bing; Liu, Yongming et al. (2014) Insulin inhibits cardiac contractility by inducing a Gi-biased ?2-adrenergic signaling in hearts. Diabetes 63:2676-89|
|Nooh, Mohammed M; Naren, Anjaparavanda P; Kim, Sung-Jin et al. (2013) SAP97 controls the trafficking and resensitization of the beta-1-adrenergic receptor through its PDZ2 and I3 domains. PLoS One 8:e63379|
|Fu, Qin; Chen, Xiongwen; Xiang, Yang K (2013) Compartmentalization of ?-adrenergic signals in cardiomyocytes. Trends Cardiovasc Med 23:250-6|
|Lim, Ji-Hong; Gerhart-Hines, Zachary; Dominy, John E et al. (2013) Oleic acid stimulates complete oxidation of fatty acids through protein kinase A-dependent activation of SIRT1-PGC1? complex. J Biol Chem 288:7117-26|
|Liu, Ruijie; Wang, Dayong; Shi, Qian et al. (2012) Palmitoylation regulates intracellular trafficking of ?2 adrenergic receptor/arrestin/phosphodiesterase 4D complexes in cardiomyocytes. PLoS One 7:e42658|
Showing the most recent 10 out of 32 publications