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Jackson, MS, United States

Ma Y.,San Antonio Cardiovascular Proteomics Center | Ma Y.,University of Mississippi Medical Center | Yabluchanskiy A.,San Antonio Cardiovascular Proteomics Center | Yabluchanskiy A.,University of Mississippi Medical Center | And 3 more authors.
Fibrogenesis and Tissue Repair

Polymorphonuclear granulocytes (PMNs; neutrophils) serve as key effector cells in the innate immune system and provide the first line of defense against invading microorganisms. In addition to producing inflammatory cytokines and chemokines and undergoing a respiratory burst that stimulates the release of reactive oxygen species, PMNs also degranulate to release components that kill pathogens. Recently, neutrophil extracellular traps have been shown to be an alternative way to trap microorganisms and contain infection. PMN-derived granule components are also involved in multiple non-infectious inflammatory processes, including the response to myocardial infarction (MI). In this review, we will discuss the biological characteristics, recruitment, activation, and removal of PMNs, as well as the roles of PMN-derived granule proteins in inflammation and innate immunity, focusing on the MI setting when applicable. We also discuss future perspectives that will direct research in PMN biology. © 2013 Ma et al.; licensee BioMed Central Ltd. Source

Heaberlin J.R.,University of Texas Health Science Center at San Antonio | Heaberlin J.R.,University of Texas at San Antonio | Ma Y.,University of Mississippi | Zhang J.,University of Texas Health Science Center at San Antonio | And 8 more authors.
Cardiovascular Pathology

Background: Introduction of the yellow obese gene (Ay) into mice (KKAy) results in obesity and diabetes by 5 weeks of age. Methods: Using this model of type 2 diabetes, we evaluated male and female 6-to 8-month-old wild-type (WT, n=10) and KKAy (n=22) mice subjected to myocardial infarction (MI) and sacrificed at day (d) 7. Results: Despite similar infarct sizes (50%±4% for WT and 49%±2% for KKAy, P=not significant), the 7d post-MI survival was 70% (n=7/10) in WT mice and 45% (n=10/22) in KKAy mice (P<.05). Plasma glucose levels were 1.4-fold increased in KKAy mice at baseline compared to WT (P<.05). Glucose levels did not change in WT mice but decreased 38% in KKAy post-MI (P<.05). End-diastolic and end-systolic dimensions post-MI were smaller and fractional shortening improved in the KKAy (5%±1% in WT and 10%±2% in KKAy, P<.05 for all). The improved cardiac function in KKAy was accompanied by reduced macrophage numbers and collagen I and III levels (both P<.05). Griffonia (Bandeiraea) simplicifolia lectin-I staining for vessel density demonstrated fewer vessels in KKAy infarcts (5.9%±0.5%) compared to WT infarcts (7.3%±0.1%, P<.05). Conclusion: In conclusion, our study in KKAy mice revealed a paradoxical reduced post-MI survival but improved cardiac function through reduced inflammation, extracellular matrix accumulation, and neovascularization in the infarct region. These results indicate a dual-role effect of obesity in the post-MI response. © 2013 Elsevier Inc. All rights reserved. Source

Ma Y.,San Antonio Cardiovascular Proteomics Center | Ma Y.,University of Mississippi Medical Center | De Castro Bras L.E.,San Antonio Cardiovascular Proteomics Center | De Castro Bras L.E.,University of Mississippi Medical Center | And 15 more authors.
Pflugers Archiv European Journal of Physiology

The cardiac extracellular matrix (ECM) fills the space between cells, supports tissue organization, and transduces mechanical, chemical, and biological signals to regulate homeostasis of the left ventricle (LV). Following myocardial infarction (MI), a multitude of ECM proteins are synthesized to replace myocyte loss and form a reparative scar. Activated fibroblasts (myofibroblasts) are the primary source of ECM proteins, thus playing a key role in cardiac repair. A balanced turnover of ECM through regulation of synthesis by myofibroblasts and degradation by matrix metalloproteinases (MMPs) is critical for proper scar formation. In this review, we summarize the current literature on the roles of myofibroblasts, MMPs, and ECM proteins in MI-induced LV remodeling. In addition, we discuss future research directions that are needed to further elucidate the molecular mechanisms of ECM actions to optimize cardiac repair. © 2014 The Author(s). Source

Oki K.,Research and Medicine Services | Oki K.,University of Mississippi Medical Center | Plonczynski M.W.,Research and Medicine Services | Plonczynski M.W.,University of Mississippi Medical Center | And 6 more authors.

Angiotensin II (A-II) regulation of aldosterone secretion is initiated by inducing cell membrane depolarization, thereby increasing intracellular calcium and activating the calcium calmodulin/calmodulin kinase cascade. Mutations in the selectivity filter of the KCNJ5 gene coding for inward rectifying potassium channel (Kir)3.4 has been found in about one third of aldosterone-producing adenomas. These mutations result in loss of selectivity of the inward rectifying current for potassium, which causes membrane depolarization and opening of calcium channels and activation of the calcium calmodulin/calmodulin kinase cascade and results in an increase in aldosterone secretion. In this study we show that A-II and a calcium ionophore down-regulate the expression of KCNJ5 mRNA and protein. Activation of Kir3.4 by naringin inhibits A-II-stimulated membrane voltage and aldosterone secretion. Overexpression of KCNJ5 in the HAC15 cells using a lentivirus resulted in a decrease in membrane voltage, intracellular calcium, expression of steroidogenic acute regulatory protein, 3-β-hydroxysteroid dehydrogenase 3B2, cytochrome P450 11B1 and cytochrome P450 11B2 mRNA, and aldosterone synthesis. In conclusion, A-II appears to stimulate aldosterone secretion by depolarizing the membrane acting in part through the regulation of the expression and activity of Kir3.4. Copyright © 2012 by The Endocrine Society. Source

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