Macrophage-mediated interleukin-6 signaling drives ryanodine receptor 2 calcium leak in postoperative atrial fibrillation

Active Project Grant Awarded Last action

Award ID
F30HL172431
Recipient
Awarding agency
Obligated
$148,296

Award facts

Assistance listing
93.837 Cardiovascular Diseases Research
Completion date 70% complete
Place of performance
Houston, TX 77030, USA

Award details come from USAspending.gov.

Description

As the agency reported it.

Abstract
There is a fundamental GAP in the understanding of the molecular drivers of postoperative atrial fibrillation (poaf), which is self-limited atrial fibrillation (AF) 2-4 days after surgery. The recurrence rate of AF is eight-fold greater and mortality risk two-fold greater in poaf patients compared to those that remain in sinus rhythm after surgery. Thus, IT is apparent that current poaf treatments such as beta-blockers, while effective in reducing acute arrhythmia-related symptoms, do not adequately target the underlying molecular drivers of poaf. As can be expected after surgery, there is systemic inflammation secondary to tissue damage, and studies show that the degree of systemic inflammation positively correlates with poaf risk. Current anti-inflammatory agents such as non-steroidal anti-inflammatory drugs target a broad spectrum of inflammatory mediators and have unwanted side effects such as acute kidney injury and immunosuppression. Therefore, the rationale for this project is that targeting a precise molecular pathway within specific cell types has the potential of decreasing poaf and, more importantly, recurrent AF risk without the unwanted side effects of current anti-inflammatory agents. To this end, our lab has recently developed and published a novel poaf mouse model consisting of atrial pericardiectomy and transient aortic clamping. We and others have shown that interleukin (IL)-6 is reproducibly and robustly elevated in the atria of mice with poaf. In addition, we have found that atrial macrophages mediate atrial IL-6 signaling through production of the IL-6 receptor alpha (IL-6R), which activates CA2+/calmodulin-dependent protein kinase II (camkii) in nearby atrial cardiomyocytes (acms) and leads to arrhythmogenic ryanodine receptor-2 (RYR2) CA2+ leak. The overall objective of this proposal is to identify whether inhibiting atrial IL-6 signaling at multiple levels can abrogate arrhythmogenic RYR2 CA2+ leak and poaf. We hypothesize that macrophages, which infiltrate the atria 48-72 hours after cardiac surgery, promote IL-6 trans-signaling to acms through release of IL-6R, resulting in STAT3-mediated camkii transcriptional upregulation and RYR2 phosphorylation at SER2814 and CA2+ leak. We will test this hypothesis with the following two aims. Aim 1 will assess whether atrial IL-6 signaling mediated by macrophages is necessary for poaf. Aim 2 will test whether STAT3 activation is required for RYR2 CA2+ leak. This project will constitute a significant advancement in the identification of a targeted treatment for poaf via the IL-6 signaling axis, which has broad impacts on other types of arrhythmias as well as cardiovascular diseases such as heart failure and atherosclerosis that are also driven by IL-6-mediated systemic inflammation.

Transactions

Action Obligated Date
Amendment $49,808
Amendment $49,244
Amendment $49,244
Original award $0

Quick answers

Who received award F30HL172431?

F30HL172431 was awarded to Baylor College Of Medicine by National Heart Lung and Blood Institute (National Institutes of Health) on January 31, 2025.

How much is award F30HL172431 worth?

$148,296 has been obligated on F30HL172431.

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