Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.64898/2026.09.19.749544

The RNA modification N6-methyladenosine restrains SIRPα to license myeloid efferocytosis in atherosclerosis

Kallapur, A.·Li, X.·Rodriguez-Sanchez, E.·Zhang, Z.·Sinha, A.·Cheng, L.·Wang, D.·Gu, J.·Kim, J.·Wu, X.·Li, W.·Cui, Y.·He, X.·He, C.·Sallam, T.
View original source ↗Export metadata ↓

Abstract

Background: Macrophages participate in atherosclerotic plaque development, progression and resolution, integrating lipid and inflammatory cues to balance tissue damage and repair. Despite considerable understanding of macrophage function in atherosclerosis, the underlying regulatory mechanisms governing these responses continue to evolve. Emerging evidence implicates epitranscriptomic gene regulation by the RNA modification N6-methyladenosine (m6A) in control of context specific immune responses, but its role in atherosclerosis is not well-defined. Methods: We integrated m6A quantitative trait loci (m6A QTLs) with Coronary Artery Disease (CAD) GWAS summary statistics. Using Oxford Nanopore direct RNA sequencing and MeRIP-seq, we constructed a high-resolution map of m6A modifications in macrophages. To determine the functional consequences of myeloid m6A loss in-vivo, we generated a myeloid-specific loss-of-function mouse model of m6A (Mettl14f/f LysMCre) and performed atherosclerosis studies using bone marrow transplantation into irradiated Ldlr-/- mice. Atherosclerosis lesions were analyzed using light microscopy and immunofluorescence imaging, with complementary in-vitro mechanistic studies performed in murine bone marrow derived macrophages (BMDMs). Results: m6A quantitative trait loci (m6A-QTLs) were enriched in CAD GWAS loci relevant to immune and lipid function, implicating m6A regulation in human CAD genetics. Using Oxford Nanopore direct RNA sequencing in conjunction with public MeRIP-sequencing data, we generated a single-base resolution, stoichiometric map of m6A modification in macrophages, nominating genes central to macrophage biology in atherosclerosis as high-confidence m6A targets. Myeloid specific deletion of the m6A "writer" complex subunit Mettl14 drove the development of larger, more necrotic and unstable atherosclerotic plaques on an Ldlr-/- background compared with Mettl14f/f controls, establishing an atheroprotective role for myeloid m6A. Loss of myeloid Mettl14 impaired macrophage efferocytosis in atherosclerotic plaques, in a dexamethasone-induced apoptosis in the thymus and in-vitro. Molecularly, m6A methylation of the "don't eat me" antiphagocytic receptor SIRP RNA suppressed its protein expression. Conclusions: These findings identify the myeloid m6A - SIRP axis as a novel homeostatic regulator of efferocytosis and establish epitranscriptomic remodeling as a crucial layer of macrophage regulation in atherosclerosis.

Explore related subjects

physiologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Kallapur, A., Li, X., Rodriguez-Sanchez, E., Zhang, Z., Sinha, A., Cheng, L., Wang, D., Gu, J., Kim, J., Wu, X., Li, W., Cui, Y., He, X., He, C., Sallam, T.. 2026-09-21. The RNA modification N6-methyladenosine restrains SIRPα to license myeloid efferocytosis in atherosclerosis. https://doi.org/10.64898/2026.09.19.749544

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Thoracoabdominal pressure transmission during prone and supine cardiopulmonary resuscitation in fresh-frozen human cadavers

Background: Prone cardiopulmonary resuscitation (CPR) may be necessary when turning a prone patient supine would delay chest compressions. Although prone compressions can generate arterial pressures comparable with or greater than supine CPR, the pathway of pressure transmission is uncertain. We examined synchronized intrathoracic, intra-abdominal, and central arterial pressures in both supine and prone positions. Methods: Two thawed fresh-frozen adult cadavers underwent three, 2-minute mechanical CPR trials per position in a counterbalanced crossover sequence. Solid-state catheters recorded pleural, peritoneal, and central arterial pressures simultaneously. Trial-level outcomes included peak pressure, mean pressure, pressure-time area, and the mean peritoneal-to-pleural pressure gradient. Exploratory fixed-effects models included position, cadaver, and their interaction. Results: Prone CPR increased peak intrathoracic pressure by 7.04 mmHg, peak intra-abdominal pressure by 21.69 mmHg, and peak arterial pressure by 15.40 mmHg. Mean intra-abdominal and arterial pressures increased by 16.22 and 9.90 mmHg, respectively. The mean peritoneal-to-pleural gradient reversed direction from -8.46 mmHg supine to 4.85 mmHg prone. Intrathoracic pressure-time area increased 3.4-fold, from 1.62 to 5.46 mmHg{middle dot}s, and arterial pressure-time area increased 2.2-fold, from 2.96 to 6.42 mmHg{middle dot}s. Conclusions: Compared to supine, prone mechanical CPR generated higher arterial pressures and reversed the pressure relationship across the thoracoabdominal boundary in both cadavers. Higher abdominal pressure coincided with a larger intrathoracic pressure-time area, a pattern compatible with reduced caudal pressure dissipation.

physiology↗
bioRxiv2026

Hypothalamic Farnesoid X Receptor deficiency alters energy balance by modulating hepatic glucose production and adipose tissue metabolism through central insulin signaling.

Objectives: The bile acid nuclear receptor Farnesoid X Receptor (FXR, NR1H4) is a major regulator of metabolism and energy homeostasis in peripheral organs. It modulates bile acid, glucose, and lipid metabolism, as well as fat mass and body weight. However, FXR is also expressed in the brain, particularly in the hypothalamus, a key center for the regulation of energy homeostasis. Although one study has demonstrated a role for brain FXR activation in energy balance, its specific hypothalamic role is still unknown. Here, we examined the role of FXR in the mediobasal hypothalamus in the regulation of energy balance. Methods: We used a genetic approach combined with metabolic phenotyping to determine the effect of FXR invalidation in the mediobasal hypothalamus on metabolic parameters involved in the central regulation of energy homeostasis. Results: Our results demonstrate that hypothalamic FXR deficiency induces a positive energy balance, resulting in a reduction in energy expenditure due to alterations in glucose metabolism accompanied by structural changes in white adipose tissues. Conclusion: This study uncovers a previously unrecognized role for hypothalamic FXR in the central homeostatic control of energy balance, providing new insights into its contribution to peripheral glucose metabolism and adipose tissue structural remodeling.

physiology↗
bioRxiv2026

Rad and Phospholamban are Key Drivers of the Ventricular Adrenergic Response and Stress-Induced Arrhythmia

The adrenergic response is a fundamental mechanism that regulates heart rate (chronotropy), cardiac contractility (inotropy) and relaxation (lusitropy). Adrenergic stress is also a recognized trigger of arrhythmia in disease. Yet, our understanding of the underlying molecular basis remains incomplete. Protein kinase A (PKA) and the calcium/calmodulin-dependent kinase II (CaMKII) phosphorylate multiple targets proposed to participate in the adrenergic response, including the GTP-binding protein Rad, phospholamban (PLB) and ryanodine receptor 2 (RyR2). Here we demonstrate that phosphorylation of both Rad and PLB is necessary for inotropy and lusitropy. We show that changes in cardiac contractility and relaxation are primarily dependent on intracellular calcium handling. Finally, we report that Rad and PLB control stress-induced arrhythmogenesis, despite the phosphorylation of other pro-arrhythmic targets. We have identified the essential molecular components of the adrenergic response, resolving a long-standing debate in cardiac excitation-contraction coupling and refining current models of sympathetic regulation in health and disease.

physiology↗