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Principal Investigator: Roberta Marques Lassance-Soares
Organization: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
Fiscal Year: 2024
Award: $115,125
Funding agency: National Heart Lung and Blood Institute
Abstract
Critical limb ischemia (CLI) is the end stage of peripheral artery disease (PAD) and can be an underlying
cause of ischemic rest pain, gangrene, and amputation. Primary amputation is often required for the 30% of
CLI patients who are not eligible for limb revascularization; thus, an effective therapy to improve
neovascularization is urgently needed. During hindlimb ischemia, monocytes are among the first cells to hone
in on the ischemia site and contribute to neovascularization. Our recent publication revealed that ischemia
training, performed by 24 hours of unilateral femoral artery ligation, led to functional reprogramming of bone
marrow-derived monocytes (BM-Mono), enabling them to protect against the outcomes of limb ischemia by
increasing perfusion and neovascularization. Mechanistically, this reprogramming resulted in the
downregulation of 24-Dehydrocholesterol Reductase (Dhcr24, an important enzyme that converts
desmosterol into cholesterol), and a consequent accumulation of desmosterol in those cells. Interestingly,
our preliminary data have shown that ischemic-trained monocytes control vascular proliferation, and both
vascular cell types, endothelial cells (ECs) and smooth muscle cells (SMCs), have increased expression of IL-
10 and its receptors. Moreover, the macrophages differentiated from the ischemic-trained monocytes
possess an anti-inflammatory phenotype. Here our primary scientific goal is to target Dhcr24 in monocytes
as a novel and unique strategy to improve neovascularization in the setting of PAD/CLI. First, we will assess
whether downregulation of Dhcr24 in BM-Mono improves hindlimb ischemia outcomes, such as perfusion and
neovascularization; and second, we will identify the mechanisms by which those BM-Mono with low Dhcr24
expression control vascular proliferation. Our long-term goal is to translate these findings using a Dhcr24
inhibitor into a new therapeutic approach to treat PAD/CLI. We hypothesize that the low expression of
Dhcr24 in BM-Mono regulates anti-inflammatory pathways in vascular cells that controls their proliferation,
leading to a proper neovascularization in the ischemic limb. We will test our hypothesis in two specific aims.
SA1: Determine whether monocyte Dhcr24 regulation alters hindlimb ischemia outcomes.
We will determine the dependence of loss- or gain-of-function of monocyte Dhcr24 on limb perfusion,
function, and neovascularization using a pre-clinical model of hindlimb ischemia. We expect to demonstrate
that low expression of Dhcr24 in BM-Mono plays a beneficial role against hindlimb ischemia.
SA2: Identify the mechanism by which monocytes with low Dhcr24 control vascular proliferation We
will dissect the underlying mechanisms by which monocytes with low Dhcr24 expression regulate vascular
proliferation. We will also inhibit Dhcr24 in human monocytes and assess their inflammatory phenotype. We
expect to find that the underlying mechanisms are based on anti-inflammatory pathways.
Terms: <24-Dehydrocholesterol><Adoptive Transfer><Affect><Amputation><Anti-Inflammatories><Anti-Inflammatory Agents><Anti-inflammatory><Arterial Obstruction><Arterial Occlusion><Artery Obstruction><Atherosclerosis><Atherosclerotic Cardiovascular Disease><B cell growth factor><B-Cell Differentiation Factor-1><B-Cell Growth Factor-1><B-Cell Growth Factor-I><B-Cell Proliferating Factor><B-Cell Stimulating Factor><B-Cell Stimulating Factor-1><B-Cell Stimulation Factor-1><B-Cell Stimulatory Factor-1><BCDF-1><BCGF><BCGF-1><BCSF 1><BSF-1><BSF1><Binetrakin><Biology><Blood><Blood Reticuloendothelial System><Blood Vessels><Blood capillaries><Blood flow><Blood monocyte><Bone Marrow><Bone Marrow Reticuloendothelial System><Bypass><CSIF><CSIF-10><Cell Body><Cell Growth in Number><Cell Multiplication><Cell Proliferation><Cells><Cellular Proliferation><Characteristics><Cholesterol><Closure by Ligation><Co-culture><Cocultivation><Coculture><Coculture Techniques><Cytokine Synthesis Inhibitory Factor><Data><Dehydrogenases><Demosterol><Dependence><Desmosterol><Down-Regulation><Endothelial Cells><Ensure><Enzyme Gene><Enzymes><Extremities><Failure><Future><Gangrene><Generalized Growth><Goals><Growth><Hindlimb><Hour><Human><Hypoxia><Hypoxic><IL-10><IL-4><IL10><IL10A><IL4 Protein><Immune memory><Immune system><Immunologic Memory><Immunological Memory><Inflammation><Inflammatory><Innate Immunity><Interleukin 10 Precursor><Interleukin-10><Interleukin-4><Interleukin-4 Precursor><Ischemia><Isolated limb perfusion><KI mice><Knock-in Mouse><Leiomyocyte><Ligation><Limb Perfusion><Limb structure><Limbs><Lower Extremity><Lower Limb><Lymphocyte Stimulatory Factor 1><MCGF-2><Macrophage><Marrow monocyte><Mast Cell Growth Factor-2><Mediating><Membrum inferius><Modern Man><Molecular><Muscle><Muscle Tissue><Mutant Strains Mice><Myeloid Cells><Mφ><Native Immunity><Natural Immunity><Non-Specific Immunity><Non-Trunk><Nonspecific Immunity><Outcome><Oxidoreductase><Oxidoreductase Gene><Oxygen Deficiency><Pain><Painful><Pathologic Constriction><Pathological Constriction><Pathway interactions><Patients><Perfusion><Peripheral arterial disease><Persons><Phenotype><Play><Pre-Clinical Model><Preclinical Models><Process><Proliferating><Publications><Receptor Protein><Reductases><Regulation><Rest><Role><Scientific Publication><Secondary to><Site><Smooth Muscle Cells><Smooth Muscle Myocytes><Smooth Muscle Tissue Cell><Stenosis><T-Cell Growth Factor 2><Testing><Therapeutic><Thrombosis><Tissue Growth><Training><Transgenic Organisms><Translating><Vascular Proliferation><amputated limb><anamnestic reaction><angiogenesis><artery occlusion><atheromatosis><atherosclerotic disease><atherosclerotic vascular disease><blood perfusion><capillary><cell type><critical limb Ischemia><cytokine><effective therapy><effective treatment><experiment><experimental research><experimental study><experiments><femoral artery><gain of function><improved><improved outcome><inhibitor><ischemic limb><knockin mice><limb amputation><limb ischemia><monocyte><mouse model><mouse mutant><murine model><muscular><neovascularization><new therapeutic approach><new therapeutic intervention><new therapeutic strategies><new therapy approaches><new treatment approach><new treatment strategy><novel><novel therapeutic approach><novel therapeutic intervention><novel therapeutic strategies><novel therapy approach><ontogeny><overexpress><overexpression><pathway><peripheral artery disease><pre-clinical><preclinical><receptor><revascularization><scRNA-seq><secondary immune response><single cell RNA-seq><single cell RNAseq><single cell expression profiling><single cell transcriptomic profiling><single-cell RNA sequencing><social role><thrombotic disease><thrombotic disorder><transcriptomics><transgenic><vascular>