Abstract Blood vessels provide a versatile and adaptable transport system, but recent work has established that endothelial cells, which form the innermost lining of the vascular network, are also a source of molecular signals controlling the behavior of other cell types in the surrounding tissue. Pericytes are another essential component of the vessel wall, but comparably little is known about their signaling interactions with other cell populations during organ growth and patterning. Here, we have used tissue-specific and inducible mouse genetics, high-resolution imaging, single-cell RNA sequencing and cell culture experiments to address the function of three pericyte-derived growth factors in the postnatal development of two model organs, namely lung and brain. We found that Pdgfrb-CreERT2-controlled inactivation of the gene for hepatocyte growth factor (HGF) causes no overt alterations in the postnatal brain but impairs alveologenesis in the lung due to defective interaction with AT2 epithelial cells. Likewise, expression of brain-derived neurotrophic factor (BDNF) by pericytes is not required in the postnatal brain but controls lung development through interactions with the receptor tyrosine kinase TrkB in the pulmonary endothelium. Conversely, pericyte expression of the TGFβ family growth factor Nodal is not required for lung morphogenesis but regulates blood vessel growth and barrier function in the postnatal brain, which we attribute to signaling interactions with endothelial cells, astrocytes and microglia. Taken together, our findings establish that pericytes are a critical source of angiocrine signals that control morphogenetic processes in an organ-specific fashion.

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids and leukocytes within the arterial wall. By studying the aortic transcriptome of atherosclerosis-prone apolipoprotein E (ApoE-/-) mice, we aimed to identify novel players in the progression of atherosclerosis.
RNA-Seq analysis was performed on aortas from ApoE-/- and wild-type mice. AnxA8 expression was assessed in human and mice atherosclerotic tissue and healthy aorta. ApoE-/- mice lacking systemic AnxA8 (ApoE-/-AnxA8-/-) were generated to assess the effect of AnxA8 deficiency on atherosclerosis. Bone marrow transplantation (BMT) was also performed to generate ApoE-/- lacking AnxA8 specifically in bone marrow-derived cells. Endothelial-specific AnxA8 silencing in vivo was performed in ApoE-/- mice. The functional role of AnxA8 was analysed in cultured murine cells.
RNA-Seq unveiled AnxA8 as one of the most significantly upregulated genes in atherosclerotic aortas of ApoE-/- compared to wild-type mice. Moreover, AnxA8 was upregulated in human atherosclerotic plaques. Germline deletion of AnxA8 decreased the atherosclerotic burden, the size and volume of atherosclerotic plaques in the aortic root. Plaques of ApoE-/-AnxA8-/- were characterized by lower lipid and inflammatory content, smaller necrotic core, thicker fibrous cap and less apoptosis compared with those in ApoE-/-AnxA8+/+. BMT showed that hematopoietic AnxA8 deficiency had no effect on atherosclerotic progression. Oxidized low-density lipoprotein (ox-LDL) increased AnxA8 expression in murine aortic endothelial cells (MAECs). In vitro experiments revealed that AnxA8 deficiency in MAECs suppressed P/E-selectin and CD31 expression and secretion induced by ox-LDL with a concomitant reduction in platelet and leukocyte adhesion. Intravital microscopy confirmed the reduction in leukocyte and platelet adhesion in ApoE-/-AnxA8-/- mice. Finally, endothelial-specific silencing of AnxA8 decreased atherosclerosis progression.
Our findings demonstrate that AnxA8 promotes the progression of atherosclerosis by modulating endothelial-leukocyte interactions. Interventions capable of reducing AnxA8 expression in endothelial cells may delay atherosclerotic plaque progression.
This study shows that AnxA8 is upregulated in aorta of atheroprone mice and in human atherosclerotic plaques. Germline AnxA8 deficiency reduces platelet and leukocyte recruitment to activated endothelium as well as atherosclerotic burden, plaque size, and macrophage accumulation in mice. AnxA8 regulates oxLDL-induced adhesion molecules expression in aortic endothelial cells. Our data strongly suggest that AnxA8 promotes disease progression through regulation of adhesion and influx of immune cells to the intima. Endothelial specific silencing of AnxA8 reduced atherosclerosis progression. Therapeutic interventions to reduce AnxA8 expression may delay atherosclerosis progression.
© 2025 The Author(s). Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.

Functional cell death pathways are essential for normal ocular vascular development and tissue homeostasis. As our understanding of necrosis-based cell death pathways has expanded, the inclusion of regulated forms, including necroptosis, ferroptosis, and oxytosis, has occurred. Although the existence of these pathways is well described, our understanding of their role during vascular development and pathological neovascularization is very limited. Here, we examined the role of receptor-interacting protein kinase-3 (Ripk3), a key regulator of necroptosis, in postnatal retinal vascularization and retinal and choroidal neovascularization under pathological conditions. Postnatal vascularization of the retinal superficial layer in the absence of Ripk3 (Ripk3-/-) was not significantly different from wild-type mice. However, we noted decreased retinal endothelial cells and pericyte numbers at 3 weeks of age when the formation of the retinal primary vascular plexus was complete. In contrast, choroidal and retinal neovascularization following laser treatment and oxygen-induced ischemic retinopathy increased in the absence of Ripk3 expression, respectively. In addition, the inhibition of RIPK1/3 activity suppressed choroidal neovascularization. Thus, Ripk3 expression and/or activity may have unique roles during normal and pathological ocular vascularization through its interactions with Caspase 8 and modulation of cell death processes.

The blood-brain barrier (BBB) protects the brain and maintains neuronal homeostasis. BBB properties can vary between brain regions to support regional functions, yet how BBB heterogeneity occurs is poorly understood. Here, we used single-cell and spatial transcriptomics to compare the mouse median eminence, one of the circumventricular organs that has naturally leaky blood vessels, with the cortex. We identified hundreds of molecular differences in endothelial cells (ECs) and perivascular cells, including astrocytes, pericytes and fibroblasts. Using electron microscopy and an aqueous-based tissue-clearing method, we revealed distinct anatomical specializations and interaction patterns of ECs and perivascular cells in these regions. Finally, we identified candidate regionally enriched EC-perivascular cell ligand-receptor pairs. Our results indicate that both molecular specializations in ECs and unique EC-perivascular cell interactions contribute to BBB functional heterogeneity. This platform can be used to investigate BBB heterogeneity in other regions and may facilitate the development of central nervous system region-specific therapeutics.
© 2024. The Author(s).

In the aging population, choroidal vessels grow through the Bruch's membrane, resulting in a loss of central vision due to choroidal neovascularization (CNV). During active neovascularization, CNV is associated with inappropriate levels of apoptosis in multiple cell types, including choroidal endothelial cells (ChECs). Bim is a pro-apoptotic member of the Bcl-2 family. It is essential for cell apoptosis due to exposure to drugs such as dexamethasone or decreased pro-survival factors, including vascular endothelial growth factor (VEGF). To better elucidate the cell autonomous contribution of Bim expression in the integrity and neovascularization of the choroidal vasculature, we isolated ChECs from wild-type and Bim-deficient (Bim-/-) mice. ChECs lacking Bim expression demonstrated increased expression of VEGF, osteopontin, and the inflammatory cytokines Rantes/Ccl5 and IL6. Bim-/- ChECs were more proliferative and demonstrated an increased capacity to undergo capillary morphogenesis. Anti-VEGF had a diminished capacity to disrupt capillary morphogenesis in Bim-/- ChECs. In vivo, utilizing the mouse laser photocoagulation model, anti-VEGF treatment mitigated CNV in wild-type but not Bim-/- mice. We also tested other modalities that are thought to not require the intrinsic death pathway for their function and showed that propranolol, anti-CTGF, and the TSP1-mimetic peptide ABT898 mitigated CNV in mice lacking Bim expression to varying degrees. Thus, in ChECs, Bim expression could impact the effectiveness of treatment modalities that require the intrinsic death pathway to mitigate CNV.