Hyperglycemia is the hallmark of type 2 diabetes (T2D) and accelerates the development of atherosclerosis, which, in turn, precedes the development of major cardiovascular complications. In people with T2D, cardiovascular disease significantly contributes to mortality, accounting for 65%-to-80% of T2D deaths. The development of pharmaceutical agents that lower glucose while also treating cardiovascular disease is therefore a priority. However, current cardiovascular agents (statins, fibrates, antihypertensives) are only moderately efficacious in T2D, partly because these agents incompletely address certain vascular abnormalities, such as inflammation, foam cell formation and leukocyte recruitment to the arterial wall. Therefore, more effective interventions are needed that treat both hyperglycemia and atherosclerosis. The goal of this proposal is to elucidate the molecular mechanisms of glucagon-like peptide-1 (GLP-1) in cardiovascular disease through the use of nanoparticle probes that target and image atherosclerosis. GLP-1 is an endogenous gut-derived hormone presently used in clinics in the form of peptide mimetics that provide glycemic control in patients with T2D. We and other investigators have demonstrated that GLP-1 exerts a multitude of effects on immune cells and has the potential to reduce atherosclerosis. We posit that GLP-1 may directly regulate immune cell behavior by activating its receptor, GLP-1R, thereby reducing monocyte recruitment to the plaque, potentiating macrophage and cholesterol exit, and resolving inflammation. In order to isolate glucose lowering and systemic effects of GLP-1 from its actions on immune cells in atherosclerosis, an effective drug delivery system would be required that favors accumulation of GLP-1 in lesional leukocytes. We propose to investigate locus-specific actions of GLP-1 with the use of engineered nanoparticles that will image lesional and blood leukocytes simultaneously delivering a payload of a GLP-1 mimetic within plaque. This technology activates the drug release in the plaque following the retention of MRI-visible nanoparticles facilitated by eat-me signals. The underlying mechanisms of the anti-atherogenic effects of GLP-1 will be evaluated by carrying out two specific aims:
Specific aim 1 will determine the inflammatory and migratory phenotype of leukocytes that were targeted by nanoparticles or GLP-1 alone. Here we will assess acute effects of GLP-1 on immune cells.
Specific aim 2 will define whether lipid or anti-inflammatory effects govern anti-atherogenicity of GLP-1. Here, we will investigate atherosclerosis inhibition depending on the locus of GLP-1 delivery following chronic treatment regimen. Organ-specific actions of GLP-1 will be explored using on-demand nanoparticle delivery via modern pegylation technologies. In sum, the significance of this proposal is that it addresses an urgent clinical need for improved treatment strategies targeting both hyperglycemia and atherosclerosis.
Patients with type 2 diabetes have greater risk of cardiovascular disease manifesting in severe complications such as stroke and heart attack. Current therapies for diabetes focus on control of hyperglycemia, while cardiovascular disease is treated separately with multiple medications that control lipid levels and blood pressure. The result of this project will be to suggest on the most efficient use of current anti-diabetic drugs and to inform on future development of novel therapies that will better treat patients with type 2 diabetes, who are also suffering from cardiovascular disease.
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