Acute myocardial infarction (AMI) is a leading cause of mortality worldwide. MicroRNAs (miRNAs), among other small non-coding RNAs, shape the transcriptome and control cellular functions. Although single-cell technologies are now available to study myocardial ischemia response, the study of small RNA regulation is limited by depth of expression, capture efficiency and lack of full coverage of transcripts. In addition, the kinetic expression of miRNAs is unknown. Using paired small and total RNA sequencing, we built an expression atlas to study the temporal dynamics of miRNAs and genes in four major heart cell types after AMI. Expression dynamics reveal enriched functions highlighting cell type-specific AMI stress responses. Many deregulated mouse genes after AMI overlap with known human cardiovascular disease genes. The dataset is highly valuable for additional research on small and long non-coding RNAs, such as regulation of RNA variants by splicing or alternative ORFs. All in all, the RNA expression atlas provides a useful resource to study different roles of RNAs in major cell types of the heart after AMI.
© 2025. The Author(s).

Aging is accompanied by a decline in neovascularization potential and increased susceptibility to ischemic injury. Here, we confirm the age-related impaired neovascularization following ischemic leg injury and impaired angiogenesis. The age-related deficits in angiogenesis arose primarily from diminished EC proliferation capacity, but not migration or VEGF sensitivity. Aged EC harvested from the mouse skeletal muscle displayed a pro-angiogenic gene expression phenotype, along with considerable changes in metabolic genes. Metabolomics analysis and 13C glucose tracing revealed impaired ATP production and blockade in glycolysis and TCA cycle in late passage HUVECs, which occurred at nicotinamide adenine dinucleotide (NAD⁺)-dependent steps, along with NAD+ depletion. Supplementation with nicotinamide mononucleotide (NMN), a precursor of NAD⁺, enhances late-passage EC proliferation and sprouting angiogenesis from aged mice aortas. Taken together, our study illustrates the importance of NAD+-dependent metabolism in the maintenance of EC proliferation capacity with age, and the therapeutic potential of NAD precursors.
© 2024 The Author(s).

Cellular senescence contributes to inflammation and organ dysfunction during aging. While this process is generally characterized by irreversible cell cycle arrest, its morphological features and functional impacts vary in different cells from various organs. In this study, we examined the expression of multiple senescent markers in the lungs of young and aged humans and mice, as well as in mouse lung endothelial cells cultured with a senescence inducer, suberoylanilide hydroxamic acid (SAHA), or doxorubicin (DOXO). We detected increased levels of p21, γH2AX, and SA-β-Gal and decreased Ki-67 and Lamin B1 in aged lungs and senescent lung endothelial cells. Importantly, the expression of senescent markers was associated with an inflammatory response in aged mouse lungs characterized by neutrophil infiltration, increased expression of intercellular adhesion molecule 1 (ICAM-1), and decreased protein levels of VE-cadherin and ZO-1. As the latter two are critical constituents of endothelial cell-cell junctions, we hypothesized that their decreased expression could lead to compromised junction barrier integrity. Indeed, senescent endothelial cells (ECs) exhibited impaired barrier properties, as measured by increased permeability to solutes of small size (3-kD) and albumin (70-kD). When co-cultured with neutrophils, senescent ECs and their supernatant promoted neutrophil chemotaxis and trans-endothelial migration. Taken together, our results suggest that lung EC senescence weakens cell-cell junctions, impairs barrier function, and promotes neutrophil adhesion and migration, which may contribute to the development of inflammation and related pathologies in the lungs during aging.
© 2025. The Author(s).

Intraflagellar transport (IFT) proteins are required for the assembly and function of primary cilia. They also regulate non-ciliary polarized vesicular traffic, such as T cell receptor recycling. We recently reported that lymphatic endothelial cells assemble primary cilia and express IFT proteins. Here, we report that IFT20 regulates vascular endothelial cadherin (VE-cadherin) localization at adherens junctions. IFT20 deletion caused discontinuous, button-like interendothelial junctions. This resulted in excessive lymphangiogenesis and impaired lymph drainage in mice. In vitro, VEGF-C treatment of IFT20 KD primary human dermal lymphatic endothelial cells caused accumulation of VE-cadherin in RAB5+ endosomes and enhanced and sustained VEGFR-3 signaling. Our findings are consistent with a model in which IFT20 promotes recycling of VE-cadherin to the adherens junction where it sequesters VEGFR-3 at the cell surface, thereby limiting pro-lymphangiogenic signaling. In the absence of IFT20, intercellular junctions are destabilized, pro-lymphangiogenic VEGFR-3 signaling is enhanced, and lymph transport is impaired by intracellular sequestration of VE-cadherin. This study elucidates the function of an IFT protein in lymphatic endothelial cells and provides mechanistic insight into the processes that regulate lymphatic endothelial cell-cell junctions and lymphangiogenic signaling.

Systemic capillary leak syndrome (SCLS) is a rare life-threatening disorder due to profound vascular leak. The trigger and the cause of the disease are currently unknown and there is no specific treatment. Here, we identified a rare heterozygous splice-site variant in the TLN1 gene in a familial SCLS case, suggestive of autosomal dominant inheritance with incomplete penetrance. Talin1 has a key role in cell adhesion by activating and linking integrins to the actin cytoskeleton. This variant causes in-frame skipping of exon 54 and is predicted to affect talin's C-terminal actin-binding site (ABS3). Modeling the SCLS-TLN1 variant in TLN1-heterozygous endothelial cells (ECs) disturbed the endothelial barrier function. Similarly, mimicking the predicted actin-binding disruption in TLN1-heterozygous ECs resulted in disorganized endothelial adherens junctions. Mechanistically, we established that the SCLS-TLN1 variant, through the disruption of talin's ABS3, sequestrates talin's interacting partner, vinculin, at cell-extracellular matrix adhesions, leading to destabilization of the endothelial barrier. We propose that pathogenic variants in TLN1 underlie SCLS, providing insight into the molecular mechanism of the disease that can be explored for future therapeutic interventions.