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Biology subjects

Grogan, A.

Publications and source records attributed to Grogan, A..

3 recordsLinked to original sources

RNA polymerase loss by nuclear rupture drives LMNA cardiomyopathy

Localized rupture of the nuclear envelope has recently been reported in various pathologies, including cancer 1,2, neurodegenerative disease 3-5, myocardial infarction 6, as well as dilated cardiomyopathy caused by Lamin A/C gene mutations (LMNA-DCM) 7. Whether and how nuclear rupture contributes to disease remains unknown. Here, we report that nuclear rupture causes global transcriptional deficiency in a mouse model of LMNA-DCM. We observed that ruptured nuclei lost RNA polymerase II, leading to downregulation of numerous genes essential for cardiomyocyte structure and function. We identified endogenous resealing of nuclear rupture as a cardioprotective mechanism in LMNA-DCM mouse hearts. Resealing involved the ESCRT-III membrane remodeling complex recruited to nuclear rupture sites. Resealed nuclei restored transcription while inhibiting ESCRT-III activity accelerated cardiomyopathy. However, resealed nuclei were short-lived: they re-ruptured at twice the rate of resealing. A kinetic model predicted progressive accumulation of ruptured nuclei despite ongoing resealing. Consistently, a human LMNA-DCM heart contained numerous ruptured nuclei at disease presentation. These findings linked nuclear rupture to organ deterioration through global transcriptional deficiency and suggested rupture resealing as a critical modifier of nuclear rupture-associated conditions.

molecular biology↗

Immunoregulatory gene GIMAP6 suppresses lethal atherosclerotic vasculopathy and ischemic heart failure

Controlling hyperlipidemia has reduced but not eliminated atherosclerotic cardiovascular disease as a predominant cause of human mortality. Here, we report that loss of the immunoregulatory gene GTPase of immunity-associated protein 6 (GIMAP6), causes an inflammatory vasculopathy and accelerated atherosclerosis in the absence of hyperlipidemia. These pathologic changes in turn result in progressive cardiac ischemia, myocardial infarction, and heart failure, culminating in early death. In humans, rare deleterious GIMAP6 variants are associated with premature severe cardiovascular disease. These findings reveal GIMAP6 to play an important protective role against atherosclerotic cardiovascular disease whose identification offers opportunities for improved risk management and a target for new therapies.

immunology↗

Th9-endothelial cell crosstalk promotes inflammatory atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of death, and understanding its pathogenic drivers is critical for effective prevention and treatment. Inflammation has a critical role in ASCVD, and patients with inflammatory diseases are at increased risk. However, the key inflammatory mediator promoting ASCVD are incompletely understood, a major barrier when targeting inflammation to prevent ASCVD. Here, we found that interleukin-9 (IL-9) producing T helper cells (Th9) were significantly associated with ASCVD in patients with the autoimmune disease psoriasis. Th9 cells were poised to migrate to coronary vessels and were identified in atherosclerotic plaque. In vivo, murine inflammatory atherogenesis was prevented by IL-9 blockade and by IL-9 receptor (IL-9R) deletion in endothelial cells. In human arterial endothelial cells, IL-9R/STAT3 signaling promoted endothelial dysfunction, angiogenesis, and release of leukocyte chemoattractants. These findings suggest that in autoimmune diseases like psoriasis, Th9/IL-9 promote atherosclerosis by directly targeting endothelial cells, and that IL-9R/STAT3 signaling could be a promising therapeutic target for ASCVD. eTOC SummaryBaral et. al. investigate individuals who are at high risk for atherosclerosis due to underlying inflammatory disease and use mouse models of cardiovascular disease to uncover a role for interleukin-9-producing T helper 9 cells in the pathogenesis of inflammatory atherosclerosis.

immunology↗