Ana Mompeón

Spatiotemporal control of adherens junction fluidity and integrity is critical for angiogenesis, but underlying mechanisms are incompletely understood. To identify unappreciated regulators of endothelial adherens junctions, we performed VE-cadherin proximity ligation mass spectrometry, revealing significant interaction with the multifunctional scaffold Scrib. Utilizing a 3D angiogenesis-on-chip model, we find Scrib-depleted microvessels generate reduced intact sprouts and increased single-cell detachments. This defect was characterized by adherens junction instability and decreased actomyosin in the junctional cortex, yet was not caused by changes in catenin-dependent VE-cadherin coupling to actin. Instead, Scrib controls the formation of cortical actomyosin clusters, which critically organize the architecture and dynamics of the junctional actomyosin cortex to promote adherens junction stability. We further discovered that unconventional myosin-1c is a critical effector linking Scrib cortical dynamics and VE-cadherin to stabilize adherens junctions during angiogenic initiation. Our results demonstrate a new role for Scrib directing cortical actomyosin organization that is critical for precise control of adherens junctions during angiogenesis.

Pathology in large vessels frequently develops at specific locations, implying that local stressors and spatially restricted gene expression are likely contributors to disease susceptibility. Here we perform single-cell transcriptomics in the carotids, the aortic arch and the thoracic and abdominal aorta to identify site- and sex-specific differences that could inform about vulnerability. Our findings revealed (1) regionally defined transcriptional profiles, (2) signatures associated with embryonic origins and (3) differential contributions of sex-specific effectors. Furthermore, cross-referencing regional-specific signatures with available genome-wide association study and expression quantitative trait loci databases identified 339 disease candidates associated with aorta distensibility, stiffness index and blood pressure. CPNE8 and SORBS2 were further evaluated and highlighted as strong causal candidates. Sex differences were predominantly observed in the thoracic and abdominal aorta. MCAM (CD146), a transcript with sex-skewed expression and lower in male mice and men, had significantly reduced expression in human aortic aneurysms. The findings reveal underlying diversity within vascular smooth muscle cell populations relevant to understanding site-specific and sex-specific variation of vascular pathologies.

SUMMARY: After birth, tissues grow continuously until reaching adult size, with each organ exhibiting unique cellular dynamics, growth patterns, and (stem or non-stem) cell sources. Using a suite of experimental and computational multiscale approaches, we found that aortic expansion is guided by specific biological principles and scales with the vertebral column rather than animal body weight. Expansion proceeds via two distinct waves of arterial cell proliferation along blood flow that are spatially stochastic, yet temporally coordinated. Each wave exhibits unique cell cycle kinetics and properties, with the first wave exhibiting cell cycle durations as fast as 6 hours. Single-cell RNA sequencing showed changes in fatty acid metabolism concomitant with an increase in cell size. Mathematical modeling and experiments indicated endothelial cell extrusion is essential for homeostatic aortic growth and balancing excess proliferation. In a genetic model of achondroplasia, the aorta achieves proper scaling through enhanced cell extrusion while maintaining normal proliferation dynamics. Collectively, these results provide a blueprint of the principles that orchestrate aortic growth which depends entirely on differentiated cell proliferation rather than resident stem cells.

Vascular aging affects multiple organ systems, including the brain, where it can lead to vascular dementia. However, a concrete understanding of how aging specifically affects the brain vasculature, along with molecular readouts, remains vastly incomplete. Here, we demonstrate that aging is associated with a marked decline in Notch3 signaling in both murine and human brain vessels. To clarify the consequences of Notch3 loss in the brain vasculature, we used single-cell transcriptomics and found that Notch3 inactivation alters regulation of calcium and contractile function and promotes a notable increase in extracellular matrix. These alterations adversely impact vascular reactivity, manifesting as dilation, tortuosity, microaneurysms, and decreased cerebral blood flow, as observed by MRI. Combined, these vascular impairments hinder glymphatic flow and result in buildup of glycosaminoglycans within the brain parenchyma. Remarkably, this phenomenon mirrors a key pathological feature found in brains of patients with CADASIL, a hereditary vascular dementia associated with NOTCH3 missense mutations. Additionally, single-cell RNA sequencing of the neuronal compartment in aging Notch3-null mice unveiled patterns reminiscent of those observed in neurodegenerative diseases. These findings offer direct evidence that age-related NOTCH3 deficiencies trigger a progressive decline in vascular function, subsequently affecting glymphatic flow and culminating in neurodegeneration.

Phenotypes of the human pancreatic cell Ines and effects on endothelium

Work flow to assess effects of drug hits in vivo

Summary of the drug screening findings using both MiaPaCa-2 and PaTu-8902 tumor cells

Work flow to assess effects of drug hits in vivo

Phenotypes of the human pancreatic cell Ines and effects on endothelium