Apln-CreERT:mT/mG reporter mice as a tool for sprouting angiogenesis study

Abstract Background Angiogenesis is defined as a new blood vessel sprouting from pre-existing vessels, and the sprouting angiogenesis is the start phase of angiogenesis, which is critical for both physiological and pathological processes, such as embryonic development, organ growth, wound healing, tumor growth, diabetic retinopathy and age-related macular degeneration. Better understanding of the mechanisms of sprout angiogenesis will provide a rationale for the treatments of these angiogenesis related diseases. Methods mT/mG tool mice are crossed with Apln-CreERT mice to generate Apln-CreERT: mT/mG mice, then we used neonatal retinal angiogenesis model to observe the angiogenic pattern of Apln-CreERT:mT/mG mice compared with Cdh5-CreERT:mT/mG mice. FACS analysis was used to sort eGFP and tdTomato endothelial cells (ECs) for measuring Apelin and Cdh5 expression. Retinal sprouting angiogenesis pattern was also observed at different neonatal time when induced by tamoxifen and at hypoxia condition, as well as in vivo tumor in real-time angiogenesis in a dorsal skinfold window chamber in Apln-CreERT:mT/mG mice. Results Apln-CreERT:mT/mG mice exhibited eGFP signal only in the sprouting angiogenesis, with less eGFP expression in the retinal “optic nerve” area than in that of Cdh5-CreERT: mT/mG mice, which might be due to relative mature vessels in the “optic nerve” area. The ECs sorted by FACS confirmed that the Apelin expression level was higher in eGFP ECs than tdTomato ECs of “optic nerve” area. Further we found that GFP-labeled sprouting angiogenesis decreased gradually following tamoxifen administration from P5-P7, but increased significantly during hypoxia in Apln-CreERT:mT/mG mice. At last, using Apln-CreERT:mT/mG mice we found tumor sprouting angiogenesis in dorsal skinfold, but not in the normal skinfold tissue. Conclusions Apln-CreERT:mT/mG mouse line is a useful tool to differentiate sprouting angiogenesis from whole blood vessels in the investigation of retinal and tumor sprouting angiogenesis in vivo

Endothelial Gata6 deletion reduces monocyte recruitment and proinflammatory macrophage formation and attenuates atherosclerosis through Cmpk2-Nlrp3 pathways

Endothelial dysfunction results in chronic vascular inflammation, which is critical for the development of atherosclerotic diseases. Transcription factor Gata6 has been reported to regulate vascular endothelial cell activation and inflammation in vitro. Here, we aimed to explore the roles and mechanisms of endothelial Gata6 in atherogenesis.Endothelial cell (EC) specific Gata6 deletion was generated in the ApoeKO hyperlipidemic atherosclerosis mouse model. Atherosclerotic lesion formation, endothelial inflammatory signaling, and endothelial-macrophage interaction were examined in vivo and in vitro by using cellular and molecular biological approaches. EC-GATA6 deletion mice exhibited a significant decrease in monocyte infiltration and atherosclerotic lesion compared to littermate control mice. Cytosine monophosphate kinase 2 (Cmpk2) was identified as a direct target gene of GATA6 and EC-GATA6 deletion decreased monocyte adherence, migration and pro-inflammatory macrophage foam cell formation through regulation of the CMPK2-Nlrp3 pathway. Endothelial target delivery of Cmpk2-shRNA by intercellular adhesion molecule 2 (Icam-2) promoter-driven AAV9 carrying the shRNA reversed the Gata6 upregulation mediated elevated Cmpk2 expression and further Nlrp3 activation and thus attenuated atherosclerosis. In addition, C–C motif chemokine ligand 5 (Ccl5) was also identified as a direct target gene of Gata6 to regulate monocyte adherence and migration influencing atherogenesis.This study provides direct in vivo evidence of EC-GATA6 involvement in the regulation of Cmpk2-Nlrp3, as well as Ccl5, on monocyte adherence and migration in atherosclerosis development and advances our understanding of the in vivo mechanisms of atherosclerotic lesion development, and meanwhile provides opportunities for future therapeutic interventions

Endothelial Foxp1 Regulates Neointimal Hyperplasia Via Matrix Metalloproteinase‐9/Cyclin Dependent Kinase Inhibitor 1B Signal Pathway

Background The endothelium is essential for maintaining vascular physiological homeostasis and the endothelial injury leads to the neointimal hyperplasia because of the excessive proliferation of vascular smooth muscle cells. Endothelial Foxp1 (forkhead box P1) has been shown to control endothelial cell (EC) proliferation and migration in vitro. However, whether EC‐Foxp1 participates in neointimal formation in vivo is not clear. Our study aimed to investigate the roles and mechanisms of EC‐Foxp1 in neointimal hyperplasia. Methods and Results The wire injury femoral artery neointimal hyperplasia model was performed in Foxp1 EC‐specific loss‐of‐function and gain‐of‐function mice. EC‐Foxp1 deletion mice displayed the increased neointimal formation through elevation of vascular smooth muscle cell proliferation and migration, and the reduction of EC proliferation hence reendothelialization after injury. In contrast, EC‐Foxp1 overexpression inhibited the neointimal formation. EC‐Foxp1 paracrine regulated vascular smooth muscle cell proliferation and migration via targeting matrix metalloproteinase‐9. Also, EC‐Foxp1 deletion impaired EC repair through reduction of EC proliferation via increasing cyclin dependent kinase inhibitor 1B expression. Delivery of cyclin dependent kinase inhibitor 1B‐siRNA to ECs using RGD (Arg‐Gly‐Asp)‐peptide magnetic nanoparticle normalized the EC‐Foxp1 deletion‐mediated impaired EC repair and attenuated the neointimal formation. EC‐Foxp1 regulates matrix metalloproteinase‐9/cyclin dependent kinase inhibitor 1B signaling pathway to control injury induced neointimal formation. Conclusions Our study reveals that targeting EC‐Foxp1‐matrix metalloproteinase‐9/cyclin dependent kinase inhibitor 1B pathway might provide future novel therapeutic interventions for restenosis

Integrated Analysis of Genetic Ancestry and Genomic Alterations across Cancers

Disparities in cancer care have been a long-standing challenge. We estimated the genetic ancestry of The Cancer Genome Atlas patients, and performed a pan-cancer analysis on the influence of genetic ancestry on genomic alterations. Compared with European Americans, African Americans (AA) with breast, head and neck, and endometrial cancers exhibit a higher level of chromosomal instability, while a lower level of chromosomal instability was observed in AAs with kidney cancers. The frequencies of TP53 mutations and amplification of CCNE1 were increased in AAs in the cancer types showing higher levels of chromosomal instability. We observed lower frequencies of genomic alterations affecting genes in the PI3K pathway in AA patients across cancers. Our result provides insight into genomic contribution to cancer disparities. [Display omitted] •The genetic ancestry of TCGA patients was estimated at global and local levels•The Cancer Genetic Ancestry Atlas, a publicly accessible resource, was developed•The frequencies of TP53 mutations and CCNE1 amplification were higher among AAs•The frequencies of the alterations in the PI3K pathway were lower among AAs By analyzing TCGA cohorts, Yuan et al. show that breast, head and neck, and endometrial cancers of African Americans (AA) have higher levels of chromosomal instability than those of European Americans whereas the frequency of genetic alternations in the PI3K pathway in AA patients is lower across cancers