The MAACS project began with the recruitment of two carefully selected patient groups: 200 individuals who had experienced an acute myocardial infarction (MI), a severe form of acute coronary syndrome (ACS), and 150 individuals with stable angina (SA). Blood samples were collected from MI patients within 24 to 48 hours after the heart attack—a critical time window for capturing immune system activity that may influence the risk of complications such as heart failure. Importantly, MI patients were monitored for 12 months to track changes in heart function and identify those who showed either improvement or decline over time.
From these samples, we isolated peripheral blood mononuclear cells (PBMCs)—a type of immune cell known to interact with damaged heart tissue. High-quality RNA was extracted from these cells and used in multiple streams of investigation:
• Quantification of RNA modifications, specifically N6-methyladenosine (m⁶A), using highly sensitive liquid chromatography-mass spectrometry (LC/MS) at LIH Metabolomic platofrm.
• Direct RNA sequencing using Oxford Nanopore Technologies (ONT) at LIH in collaboration with McGill University, enabling the detection of RNA modifications at the single-nucleotide level.
• Bioinformatic analysis to uncover gene activity patterns and RNA modification profiles linked to adverse cardiac outcomes.
This integrated approach revealed striking differences between MI and SA patients. We identified a set of genes that were more or less active, especially those related to immune cells such as monocytes and neutrophils—key players in inflammation and healing. At the same time, hundreds of RNA molecules showed altered m⁶A modification, though these changes were not specific to a particular immune cell type. Additionally, we found that several different types of RNA modifications measured by LC/MS were associated with ACS, suggesting broader regulatory disruptions in RNA biology during acute cardiac events.
Using advanced computational tools, we analyzed the data from multiple angles. One key analysis revealed that a group of genes most responsible for variability between patients was highly linked to immune system responses. A separate group, composed only of RNA modification sites, was found to be strongly associated with MI, suggesting that RNA modifications may provide an independent layer of regulation beyond gene activity alone. These modifications were linked to processes such as RNA metabolism, transport, and cellular signaling—indicating potential new targets for understanding and treating complications following a heart attack.
Together, these findings represent a major step forward in understanding how the immune system and RNA biology interact after heart attacks, and lay the groundwork for future diagnostic and therapeutic strategies.
