Document text
Principal Investigator: Alan Ross Morrison
Organization: OCEAN STATE RESEARCH INSTITUTE, INC.
Fiscal Year: 2024
Award: $67,877
Funding agency: National Heart Lung and Blood Institute
ABSTRACT:
Aging and age-related diseases like peripheral artery disease (PAD) lead to considerable morbidity and
mortality. Aging is associated with impaired inflammatory arteriogenesis responses to injury. We defined a
macrophage signaling axis that activates the mRNA stabilizing protein, HuR, to promote VEGF-A expression
required for arteriogenesis. We seek to understand the effects of aging on this pathway. Moderately aged (52-
week-old) mice demonstrated reduced blood flow recovery and decreased arteriogenesis relative to young (12-
week-old) mice in a femoral artery ligation model of ischemia. In aged mice, ischemic muscle tissue and
macrophages revealed reduced VEGF-A expression. Aged macrophages demonstrated increased global DNA
methylation, and though macrophage HuR expression was normal, there was reduced HuR binding to VEGF-A
mRNA with consequent shortened VEGF-A mRNA half-life. Somewhat surprisingly, Dicer1, previously
established as destabilizing for VEGF-A mRNA, was downregulated in aged macrophages. The DNMT
inhibitor, RG108, led to increased Dicer1 and VEGF-A expression and increased HuR binding to VEGF-A
mRNA. miR-29, as a 3p miRNA, appears to be particularly sensitive to changes in Dicer1 expression. Aged
macrophages had decreased expression of miR-29, whose seeding site in the 3′-UTR of VEGF-A is adjacent
to the HuR binding site. Transfection of macrophages with miR-29 mimic increased VEGF-A expression.
Myeloid Dicer1-deleted mice were phenotypically similar to aged mice, having decreased blood flow recovery,
decreased VEGF-A expression, and decreased HuR binding to VEGF-A mRNA with consequent shortened
mRNA half-life. Our hypothesis is that aging acquired methylation of Dicer1 with consequent reductions in
Dicer1 dose-sensitive microRNAs (i.e. miR-29-3p) results in reduced binding of HuR to VEGF-A mRNA and
reductions in both VEGF-A expression and consequent VEGF-A dependent angio/ arteriogenesis. Our aims
seek to 1) define Dicer1 promoter methylation in aged mice to be a major mechanism of impaired VEGF-A-
mediated arteriogenesis with aging; and 2) define the molecular mechanisms whereby the Dicer1 dose-
sensitive microRNA, miR-29-3p, promotes HuR-binding to VEGF-A mRNA with consequent message
stabilization. Our studies will lead to a paradigm shift from Dicer1 as a negative regulator of VEGF-A to that of
a positive regulator. The rescue of macrophage VEGF-A expression by demethylation of Dicer1 or noncoding
RNA (i.e. miR-29) mimics, may have profound implications in the development of treatment strategies that can
promote arteriogenesis and associated tissue preservation in the setting of severe age-related vasculopathies.
Terms: <3' Untranslated Regions><3'UTR><Acute><Age><Aging><Angioplasty><Atherosclerosis><Atherosclerotic Cardiovascular Disease><Autoregulation><Beta Proprotein Interleukin 1><Binding><Binding Sites><Biogenesis><Blood Cells><Blood Vessels><Blood flow><Body Tissues><Bypass><Cell Communication and Signaling><Cell Signaling><Chemokine Receptor Gene><Cholesterol><Chronic><Clinical><Closure by Ligation><Combining Site><CpG Islands><CpG-Rich Islands><DNA><DNA Methylation><Data><Deoxyribonucleic Acid><Diabetes Mellitus><Disease><Disorder><Dose><Functional RNA><Generalized Growth><Genes><Grant><Growth><Half-Life><Homeostasis><IL-1 beta><IL-1 β><IL-1-b><IL-1β><IL1-Beta><IL1-β><IL1B Protein><IL1F2><IL1β><Impairment><Infiltration><Inflammatory><Injury><Integrins><Integrins Extracellular Matrix><Interleukin 1beta><Interleukin-1 beta><Interleukin-1β><Intracellular Communication and Signaling><Ischemia><Isoforms><Lead><Lesion><Ligation><Macrophage><Mechanics><Mediating><Medicine><Messenger RNA><Methylation><Mice><Mice Mammals><Micro RNA><MicroRNAs><Modeling><Molecular><Molecular Interaction><Morbidity><Morbidity - disease rate><Murine><Mus><Muscle><Muscle Tissue><Myelogenous><Myeloid><Mφ><Non-Coding><Non-Coding RNA><Non-translated RNA><Noncoding RNA><Nontranslated RNA><Operative Procedures><Operative Surgical Procedures><Origin of Life><Outcome><Pathway interactions><Pb element><Perception><Peripheral Blood Cell><Peripheral arterial disease><Persons><Phenotype><Physiological Homeostasis><Play><Preinterleukin 1 Beta><Protein Isoforms><Proteins><Reactive Site><Recovery><Role><Signal Pathway><Signal Transduction><Signal Transduction Systems><Signaling><Site><Source><Surgical><Surgical Interventions><Surgical Procedure><Therapeutic><Tissue Growth><Tissue Preservation><Tissues><Transcript><Transcription Activator><Transcription Coactivator><Transcription Factor Coactivator><Transcriptional Activator><Transcriptional Activator/Coactivator><Transcriptional Coactivator><Transfection><Translations><Untranslated RNA><VEGF><VEGFA><VEGFA gene><VEGFs><Vascular Diseases><Vascular Disorder><Vascular Endothelial Growth Factor A><Vascular Endothelial Growth Factors><Vasculotropin><adhesion receptor><age associated><age associated disease><age associated disorder><age associated effects><age associated impairment><age correlated><age dependent><age dependent disease><age dependent disorder><age dependent impairment><age effect><age linked><age related><age related effects><age related human disease><age specific><age-related disease><age-related disorder><age-related impairment><aged><aged mice><aged mouse><ages><aging associated><aging effect><aging related><angiogenesis><atheromatosis><atherosclerotic disease><atherosclerotic vascular disease><biological signal transduction><blood vessel disorder><chemokine receptor><cytokine><demethylation><develop therapy><diabetes><elderly mice><elderly patient><femoral artery><healing><heavy metal Pb><heavy metal lead><impact of age><improved><influence of age><inhibitor><injuries><injury response><intervention development><intraluminal angioplasty><ischemic limb><limb ischemia><mRNA><mRNA Instability><mRNA Stability><mechanic><mechanical><miRNA><miRNAs><mortality><muscular><new growth><noncoding><novel><old mice><older patient><ontogeny><pathway><peripheral artery disease><posttranscriptional><promoter><promotor><response to injury><revascularization><social role><surgery><synergism><therapy development><transcription co-activator><transcriptional co-activator><translation><translational opportunities><translational potential><treatment development><treatment strategy><vascular><vascular dysfunction><vasculopathy>