Oral Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

Reverse Engineering to Identify the Next Therapeutic in Heart Failure with Preserved Ejection Fraction? (#158)

Jennifer Van Eyk 1 , Peter Kilfoil 1 , Ahmed Ibrahim 1 , Eduardo Marban 1
  1. Cedars-Sinai, Los Angeles, CA, United States

In Europe and North American, someone is diagnosed with Heart Failure (HF) ~ every 40 seconds. In Australia, 30% of all deaths are due to cardiovascular disease which most often ends in HF. In fact, heart disease is the single leading cause of death in Australia. Unlike traditional HF, where the heart is unable to eject sufficient blood (HF with reduced ejection fraction), where a number of effective pharmacological and medical device interventions are available, there are currently no effective treatments for HF where the heart has preserved ejection fraction (HFpEF). HFpEF has only recently been recognized and it occurs predominately in women. We have recently shown that a cell therapy, using cardiac derived cardiosphere (CDCs), in small and large animal models of HFpEF can stop and reverse some of the HFpEF phenotype. This has led to an ongoing clinical trial (Regress-HFpEF) of CDCs in HFpEF patients. Yet, the cardiac mechanistic changes induced by CDC (or the CDC-derived exosomes) and their active biologics agents are not known. This study aims to reverse engineer the CDC-induced tissue effects with specific exosome biologics to potentially identify the active therapeutic agents and pathways.
Methods and Results: Dahl salt-sensitive rats fed high-salt diet, with echocardiographically verified diastolic dysfunction, were randomly assigned to either intracoronary CDCs or placebo. Dahl rats receiving low salt diet served as controls. Total protein quantity, and isoforms and phosphorylation status of left ventricular tissues (n=6/group) were quantified by mass spectrometry. A remarkable ~40% of the proteomic changes induced when HFpEF hearts are exposed to CDCs are alterations in the transcriptional and translational subproteome - with additional changes in protein folding and stability. 5 upstream cellular regulators account for ~45% of transcriptional and translational changes induced by CDCs in the static proteome of the HFpEF heart (MYC, TGFβ1, TP53, mTOR/AKT, and HNF4A). These same 5 cellular regulatory (plus HTT and SRF) target 75% of newly synthesized proteins (assessed using L-Azidohomoalanine labeling of isolated cardiac myocyte form HFpEF animals) within the first 3 hours of treatment - interestingly, these regulators are not at play in myocytes from control rats. In addition, all 32 phosphorylation sites involved in transcription/translation that were altered with CDC treatment had predicted kinases that are regulated by these same 5 cellular regulators. Finally, detailed analyses of isolated CDC exosomes reveal 31 proteins and 5 miRNAs within the exosome cargo that can be directly linked to these same 5 cellular regulators. Individual miRNAs are able to recapitulate subset of CDC exosome activity.
Conclusion: Five potential cellular regulators that may mediated the widespread CDC-induced reprograming of the HFpEF heart are linked to a number of proteins and miRNAs within the CDC-exosome cargo leading to the possibility of these being new therapies for reversal of HFpEF.