Project description:Background: The angiogenic response to ischemia restores perfusion so as to preserve tissue. A role for mesenchymal-to-endothelial transition in the angiogenic response is controversial. This study is to determine if resident fibroblasts contribute to angiogenesis. Methods: We utilized the murine model of hindlimb ischemia, and in vivo matrigel plug assay together with lineage tracing studies and single cell RNA-sequencing (scRNA-seq) to examine the transcriptional and functional changes in fibroblasts in response to ischemia. Results: Lineage tracing using Fsp1-Cre: R26R-EYFP mice revealed the emergence within the ischemic hindlimb of a small subset of YFP+ CD144+ CD11b- fibroblasts (E*cells) that expressed endothelial cell (EC) genes. Subcutaneous administration of matrigel in Fsp1-Cre: R26R-EYFP mice generated a plug that became vascularized within 5 days. Isolation of YFP+ CD11b- cells from the plug revealed a small subset of YFP+ CD144+ CD11b- E*cells which expressed EC genes. Pharmacological or genetic suppression of innate immune signaling reduced vascularity of the matrigel plug and abrogated the generation of these E*cells. These studies were repeated using human fibroblasts, with FACS analysis revealing that a small percentage of human fibroblasts that were induced to express EC markers in the matrigel plug assay. Pharmacological suppression or genetic knockout of inflammatory signaling abolished the generation of E*cells, impaired perfusion recovery and increased tissue injury after femoral artery ligation. To further characterize these E*cells, we performed scRNA-seq and revealed eight discrete clusters of cells expressing characteristic fibroblast genes, of which two clusters (C5 and C8) also expressed some EC genes. Ischemia of the hindlimb induced expansion of clusters C5 and C8. The C8 cells did not express CD144, nor did they form networks in Matrigel, but did generate angiogenic cytokines. The C5 fibroblasts most resembled E* cells in their expression of CD144 and their ability to form EC-like networks in Matrigel. Conclusion: Together, these studies indicate the presence of subsets of tissue fibroblasts which seem poised to contribute to the angiogenic response. The expansion of these subsets with ischemia is dependent upon activation of innate immune signaling, and contributes to recovery of perfusion and preservation of ischemic tissue.
Project description:This is a TMT-labeled proteomics analysis of human skeletal muscle specimens obtained from the following groups: older adult controls, critical limb ischemia patients undergoing surgical intervention, and critical limb ischemia patients undergoing limb amputation.
Project description:Colorectal cancer (CRC) and chronic limb-threatening ischemia (CLTI) are relatively frequent and potentially fatal diseases. However, studies that are comparing clinical outcomes between CRC and CLTI patients in more advanced stages of the disease are lacking. The study aim was to evaluate outcomes of patients with colorectal cancer liver metastases (CRLM) treated by curative-intent liver resection and CLTI patients according to wound, ischemia, foot infection (WIfI) classification by comparing the short- and long-term clinical outcomes.
Project description:CD34+ cells improve the perfusion and function of ischemic limbs in humans and mice. However, there is no direct evidence of the differentiation potential and functional role of these cells in the ischemic muscle microenvironment. Here, we combined the single-cell RNA sequencing and genetic lineage tracing technology and then provided exact single-cell atlases of normal and ischemic limb tissues in human and mouse, consequently found that bone marrow-derived macrophages with antigen-presenting function migrated to the ischemic site, while resident macrophages underwent apoptosis. The macrophage oncostatin M (OSM) regulatory pathway was specifically turned on by ischemia. Simultaneously, bone marrow CD34+-derived pro-regenerative fibroblasts were recruited to the ischemia niche, where they received macrophage-released OSM, and promoted angiopoietin-like protein (ANGPTL)-associated angiogenesis. These findings provided novel mechanisms on the cellular events and cell–cell communications during tissue ischemia and regeneration, and provided new evidence that CD34+ cells serve as fibroblast progenitors promoting tissue regeneration.
Project description:Mutant MetRS in MSCs allows efficient and specific identification of dynamic cell proteomics in situ, which reflect the functions and adaptive changes of MSCs that may be leveraged to understand and improve stem cell therapy in critical limb ischemia
Project description:We aimed to develop a novel chronic and severe hindlimb ischemia mice model to properly evaluate the therapeutic effects of drug candidates in translational research for critical limb ischemia treatments. We used microarray to compare the gene expression patterns of gastrocnemius muscles at 1st week and 9th week after hindlimb ischemia model operation.
Project description:Screening of dysregulated microRNAs identified miR-375 as a potential biomarker and therapeutic target which may improve outcomes in diabetic critical limb ischemia.
Project description:Vasculogenic therapies have been investigated for the treatment of peripheral artery disease (PAD) with very limited success in clinical trials. The isoform PP2A (protein phosphatase 2)/B55alpha inhibits the activity of the prolyl hydroxylase 2 (PHD2) and activates the hypoxia inducing factor-1alpha (HIF-1alpha), playing a key role in in vessel remodeling. Thus, PP2A/B55alpha activators may have the potential to induce angiogenesis and arteriogenesis. Herein we investigated the pharmacological attributes of VCE-004.8 (Etrinabdione) and its effectiveness in a murine model of critical limb ischemia.
Project description:Human skeletal muscle disuse-atrophy is one of the main problems associated with spaceflight, bed rest, lower limb unloading, or immobilization. This study investigates the effects of 10-day unilateral lower limb suspension (ULLS) followed by 21 days of active recovery (AR) in young healthy men.