Krajbich, V. | Search bioRxiv

bioRxiv2026

Medin-Induced Pro-inflammatory and Prothrombotic Activation of Coronary Artery Endothelial Cells: A Potential Novel Mediator Linking Aging and Atherosclerosis

BackgroundAge is the most important risk factor for coronary artery disease (CAD) independent of traditional risk factors. Aging induces classic pro-inflammatory and prothrombotic vascular phenotypic changes whose molecular mediators remain poorly understood. Medin is a common cleavage product protein that accumulates in vasculature with aging and shown to cause endothelial dysfunction. Its role in CAD is unknown. The study aimed to evaluate the effects of medin on human coronary artery endothelial cell (HCAEC) pro-inflammatory and prothrombotic activation and establish the relationship between medin and coronary atherosclerosis in human decedents. MethodsHCAECs were exposed to physiologic dose of medin (5 {micro}M) for 20 hours and ribonucleic acid sequencing (RNAseq) with signaling pathway analyses and reverse transcription polymerase chain reaction of select pro-inflammatory and prothrombotic genes performed. Corresponding protein expression was measured by Western blot or enzyme linked immunosorbent assay in HCAECs exposed to medin (5 {micro}M) without or with nuclear factor-{kappa}B (NF{kappa}B) inhibitor RO106-9920 (10 {micro}M). Coronary arteries from 40 deceased individuals underwent immunohistochemistry and medin and plaque burden were quantified and their relationship evaluated. ResultsRNAseq showed predominant pro-inflammatory gene expression changes induced by medin. HCAECs treated with medin showed increased phosphorylated NF{kappa}B, elevated protein expression of interleukin (IL)-6, IL-8, monocyte chemotactic protein (MCP)-1, intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1 and plasminogen activator inhibitor (PAI)-1 and reduced protein expression of thrombomodulin; these changes were reversed by RO106-9920 co-treatment. In human tissues, coronary artery medin strongly correlated with plaque burden (R=0.76, p<0.0001) and coronary macrophage content (R=0.72, p<0.0001). Coronary arteries from decedents with myocardial infarction had higher medin than those without (5.53{+/-}2.67% versus 0.02{+/-}0.02%, p=0.0005). ConclusionsMedin induced NF{kappa}B-mediated endothelial cell pro-inflammatory and prothrombotic activation and was strongly associated with coronary plaque burden and inflammation. Medin is a novel candidate mediator linking aging and coronary atherosclerosis.

physiology↗

bioRxiv2025

Cerebral blood flow in elastin haploinsufficient and 3xTg-AD mice

Artery structural properties and Alzheimers disease (AD) pathology are individually associated with impaired cerebrovascular function; however, the interaction of these factors is unclear. Furthermore, while elastin haploinsufficient (Eln+/-) mice are known to have impaired cerebrovascular function, sex differences for this effect have not been previously studied. To answer these questions, we crossed middle-aged and old Eln+/-mice with 3xTg-AD mice. We measured cerebral blood flow (CBF) using arterial spin labeling MRI at rest and during hypercapnia to calculate cerebrovascular reactivity (CVR). We also assessed neuroinflammation by microglia and astrocyte cell counts. We found that Eln+/- mice had lower resting blood flow rate in the cerebral cortex compared with Eln+/+ mice, but Eln+/- mice had an intact hypercapnic response, resulting in better CVR compared with Eln+/+ in hippocampus. Sex did not impact resting blood flow or CVR. 3xTg-AD mice had a lower resting CBF than non-AD mice, and there was an interaction between Eln genotype and AD mutations on CVR, such that Eln+/-x 3xTg-AD mice had the poorest hippocampal CVR of all groups. Glia cell counts were highly dependent on brain region, with Eln+/- having more microglia but fewer astrocytes, while 3xTg-AD having higher both microglia and astrocytes. While sex also impacted glial cell counts, we found no interactions between sex and Eln genotype. Our results demonstrate that elastin haploinsufficiency and AD mutations individually result in lower resting CBF, and the combination of these leads to impaired CVR. NEW & NOTEWORTHYThe findings of this study demonstrate that elastin haploinsufficiency leads to lower resting cerebral blood flow, but also greater cerebrovascular reactivity. However, elastin haploinsufficiency interacts with Alzheimers disease mutations to impair cerebrovascular reactivity. These results suggest that multiple insults, such as changes to the extracellular matrix combined with genetic risk factors, are needed to impact cerebrovascular reactivity.

physiology↗