Immunomagnetic Isolation of the Vascular Wall-Resident CD34<sup>+</sup> Stem Cells from Mice

Resident CD34+ vascular wall-resident stem and progenitor cells (VW-SCs) are increasingly recognized for their crucial role in regulating vascular injury ...

southwest medical university

 Aortic aneurysm is a life-threatening disease resulted from progressive dilatation of the aorta, which can be subdivided into thoracic and abdominal aortic aneurysms. Sustained subcutaneous angiotensin II infusion can induce aortic aneurysms in mice. However, the relevance of using angiotensin II induction model to study aneurysm disease and the degree of commonality between species remain elusive.  We utilized scRNA-seq to infer aortic cell sub-structures and transcriptional profiles in clinical patient TAAs and AAAs, as well as mouse models of corresponding diseases (Ang II induction) and in healthy mouse aorta. Unbiased comparison between mice and humans explored the possible reasonability and utility of mouse Ang II-induced aortic aneurysm as a model for human aortic aneurysm diseases. Meanwhile, we performed comparative analysis of aortic aneurysms between TAA and AAA in both organisms.  We demonstrated similarities and differences of changes in the components of human and mouse cell types, and our unbiased comparison between mouse and human identified well conserved subpopulations of SMCs and macrophages. Furthermore, the results of our comparative analyses suggested different biological functions and distinct potential pathogenic genes for thoracic and abdominal aortic aneurysms. MIF and SPP1 signaling networks participated in aortic aneurysm in both organisms. This study maps aortic aneurysm and offers opportunities for future researches to investigate the potential of subpopulations or marker genes as therapy targets.

Comparative analysis of thoracic and abdominal aortic aneurysms across the segment and species at the single-cell level.

The gut microbiota are not only related to the development and occurrence of digestive system disease, but also have a bidirectional relationship with nervous system diseases via the microbiota-gut-brain axis. At present, correlations between the gut microbiota and neurological diseases, including stroke, are one of the focuses of investigation and attention in the medical community. Ischemic stroke (IS) is a cerebrovascular disease accompanied by focal neurological deficit or central nervous system injury or death. In this review, we summarize the contemporary latest research on correlations between the gut microbiota and IS. Additionally, we discuss the mechanisms of gut microbiota implicated in IS and related to metabolite production and immune regulation. Moreover, the factors of gut microbiota that affecting IS occurrence, and research implicating the gut microbiota as potential therapeutic targets for IS, are highlighted. Our review highlights the evidential relationships and connections between the gut microbiota and IS pathogenesis and prognosis.

Microbiota Metabolites and Immune Regulation Affect Ischemic Stroke Occurrence, Development, and Prognosis.

Vascular aging is directly related to several major diseases including clinical primary hypertension. Conversely, elevated blood pressure itself accelerates vascular senescence. However, the interaction between vascular aging and hypertension have not been characterized during hypertensive aging. To depict the interconnectedness of complex mechanisms between hypertension and aging, we performed single-cell RNA sequencing of aorta, femoral and mesentery arteries, respectively from male Wistar Kyoto rats (WKY) and male spontaneously hypertensive rats (SHR) aging 16 or 72 weeks. We integrated 12 datasets to map the blood vessels of senile hypertension from three perspective: vascular aging, hypertension and vascular type. We found that aging and hypertension independently exerted a significant impact on the alteration of cellular composition and artery remodeling, even greater when superimposed. Consistently, smooth muscle cells (SMCs) underwent phenotypic switching from contractile towards synthetic, apoptotic and senescent SMCs with aging/hypertension. Furthermore, we identified three sub-clusters of Spp1  high, encoding protein osteopontin (OPN), synthetic SMCs, Spp1  high matrix-activated fibroblasts and Spp1  high scar-associated macrophage involved in hypertensive aging. Spp1  high scar-associated macrophage enriched for reactive oxygen species metabolic process and cell migration associated function. Cell-cell communication analysis revealed Spp1-Cd44 receptor pairing was markedly aggravated on hypertensive aging condition. Importantly, the concentration of serum OPN significantly potentiated in aged hypertensive patients compared with normal group. Thus, we provide a comprehensive cell atlas to systematically resolve the cellular diversity and dynamic cellular communication changes of the vessel wall during hypertensive aging, identifying a protein marker OPN as a potential regulator of vascular remodeling during hypertensive aging.

Single Cell Mapping of Large and Small Arteries during Hypertensive Aging.

Extracellular adenosine triphosphate (ATP) is one of the most abundant biochemical constitutes within the stem cell microenvironment and is postulated to play critical roles in cell migration. However, it is unclear whether ATP regulates the cell migration of CD34 vascular wall-resident stem/progenitor cells (VW-SCs) and participates in angiogenesis. Therefore, the biological mechanisms of cell migration mediated by ATP was determined by in vivo subcutaneous matrigel plug assay, ex vivo aortic ring assay, in vitro transwell migration assay, and other molecular methods. In the present study, ATP dose-dependently promoted CD34 VW-SCs migration, which was more obviously attenuated by inhibiting or knocking down P2Y2 than P2Y6. Furthermore, it was confirmed that ATP potently promoted the migration of resident CD34 cells from cultured aortic artery rings and differentiation into endothelial cells in matrigel plugs by using inducible lineage tracing -CreER; R26-tdTomato mice, whereas P2Y2 and P2Y6 blocker greatly inhibited the effect of ATP. In addition, ATP enhanced the protein expression of stromal interaction molecule 1 (STIM1) on cell membrane, blocking the calcium release-activated calcium (CRAC) channel with shSTIM1 or BTP2 apparently inhibited ATP-evoked intracellular Ca elevation and channel opening, thereby suppressing ATP-driven cell migration. Moreover, extracellular signal-regulated protein kinase (ERK) inhibitor PD98059 and p38 inhibitor SB203580 remarkably inhibited ERK and p38 phosphorylation, cytoskeleton rearrangement, and subsequent cell migration. Unexpectedly, it was found that knocking down STIM1 greatly inhibited ATP-triggered ERK/p38 activation. Taken together, it was suggested that P2Y2 signaled through the CRAC channel mediated Ca influx and ERK/p38 pathway to reorganize the cytoskeleton and promoted the migration of CD34 VW-SCs. In this study, we observed that the purinergic receptor P2Y2 is critical in the regulation of vascular wall-resident CD34 cells' migration. ATP could activate STIM1-mediated extracellular Ca entry by triggering STIM1 translocation to the plasma membrane, and knockdown of STIM1 prevented ERK/p38 activation-mediated cytoskeleton rearrangement and cell migration.

Cheng Xie

southwest medical university

Immunomagnetic Isolation of the Vascular Wall-Resident CD34⁺ Stem Cells from Mice

Cheng Xie

southwest medical university

Immunomagnetic Isolation of the Vascular Wall-Resident CD34+ Stem Cells from Mice

Immunomagnetic Isolation of the Vascular Wall-Resident CD34⁺ Stem Cells from Mice