Chemokine Receptor 5 Inhibition Prevents SIV-associated Cardiac Dysfunction Katie Kelly Brennan, DVM Johns Hopkins University School of Medicine Department of Molecular and Comparative Pathobiology

Objectives Discuss HIV-associated cardiac dysfunction and describe our simian immunodeficiency virus (SIV)/macaque model Describe role of chemokine co-receptor CCR5 in virus-associated cardiac dysfunction –In vitro- assess cardiomyocytes for functional CCR5 –In vivo- CCR5 inhibition in SIV-macaque model

HIV-associated cardiac dysfunction Overt clinical cardiac manifestations: 5 to 23% Association of myocarditis with function decline undefined LV systolic and diastolic dysfunction 60% of asymptomatic HIV+ HAART

Diastolic dysfunction Functional abnormalities that exist during left ventricular relaxation and filling –Normal left ventricular volume and ejection fraction –Increased left ventricular pressure Risk for development of heart failure and reduced survival

SIV-A Model of HIV Cardiomyopathy Myocarditis observed in SIV-infected macaques LV systolic dysfunction: ventricular dilation and decreased ejection fraction Tool for understanding relationship between functional decline and host immune responses and/or viral replication Hypothesis: SIV infected macaques also develop diastolic dysfunction.

SIV-associated Diastolic Dysfunction

Diastolic Dysfunction Correlated with SIV Replication

SIV/Macaque Model: Clinical Conclusions  Diastolic dysfunction develops in SIV-infected macaques  Differences in myocardial lesions and SIV infection status not correlated to diastolic dysfunction  Diastolic dysfunction not correlated to macrophage activation  SIV RNA in heart strongly correlated with prolonged IVRT SIV is a model for HIV-associated diastolic dysfunction

CCR5 7 CC chemokine, 7-transmembrane GPCR receptor Expressed on T cells and macrophages, important to the regulation of leukocyte trafficking/activation Acting with CD4, major co-receptor for HIV and SIV –Mediates CD4 independent viral infection Hypothesis: Activation of cardiomyocyte CCR5 chemokine coreceptor triggered by binding of HIV/SIV envelope glycoprotein or cognate chemokine mediates cardiac dysfunction.

ActinCCR5 MergeMerge

In vitro assessment of cardiomyocyte CCR5 expression

CCL5 decreases contractility without altering Ca 2+ flux

Diastolic Function during Maraviroc Monotherapy in SIV-infected Macaques 6 dual innoculated rhesus macaques Maraviroc montherapy (200mg PO q12) d24 Viral load, leukocyte parameters, drug concentration & cardiac function measured over time d180

CCR5 Inhibition Modulates Viral Load

CCR5 Inhibition Preserves Diastolic Function

Conclusions SIV/macaque model is relevant to HIV-associated cardiac disease Addition of CCL5 to isolated cardiomyocytes decreased contractility which was reversed by Maraviroc –CCR5 expression on cardiomyocytes may mediate cardiac dysfunction function in vivo Maraviroc monotherapy is cardioprotective in the SIV macaque model

Thanks! Retrovirus lab Joe Mankowski Chris Zink Janice Clements David Graham Suzanne Queen Kelly Pate Sarah Beck Brandon Bullock Ming Li Chris Bartizal Alexey Lyashkov Lucio Gama Jami Karper Jamie Dorsey Veronica Aquino Molecular and Comparative Pathobiology Bob Adams Bruce Baldwin Djahida Bedja Kathy Gabrielson Department of Medicine, Cardiology Gab Tocchetti Naz Paolocci Dave Kass Rick Tunin John Gibas, Gastroenterology Pathobiology Graduate Program ACVP-STP Coalition Mark Cartwright, Merck NIH RR 07002, R01 HL (JLM)