Mouse Models of HIV-Associated Atherosclerosis

Abstract

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Several factors are implicated in the pathogenesis of CVD, and efforts have been made to reduce traditional risks, yet CVD remains a complex burden. Notably, people living with HIV (PLWH) are twice as likely to develop CVD compared to persons without HIV (PWoH). Intensive statin therapy, the first-line treatment to prevent cardiovascular events, is effective at reducing morbidity and mortality. However, statin therapy has not reduced the overall prevalence of CVD. Despite antiretroviral therapy (ART), and new guidelines for statin use, PLWH have persistent elevation of inflammatory markers, which is suggested to be a bigger driver of future cardiovascular events than low-density lipoprotein. Herein, we have summarized the development of atherosclerosis and highlighted mouse models of atherosclerosis in the presence and absence of HIV. Since most mouse strains have several mechanisms that are atheroprotective, researchers have developed mouse models to study CVD using dietary and genetic manipulations. In evaluating the current methodologies for studying HIV-associated atherosclerosis, we have detailed the benefits of integrating multi-omics analyses, genetic manipulations, and immune cell profiling within mouse models. These advanced approaches significantly enhance our capacity to address critical gaps in understanding the immune mechanisms driving CVD, including in the context of HIV.

Keywords: HIV; atherosclerosis; cardiovascular disease; inflammation; mouse models.

Figure 5

CGC⁺ CD4⁺ T cells. This figure summarizes the main findings on the role of CGC⁺ CD4⁺ T cells in cardiometabolic disease among PLWH [74,75,76,88,89].

Figure 1

Overview of technologies used to modify mice for research. This table summarizes various genetic manipulation techniques, including their mechanisms, applications, advantages, cost, time, and limitations. Techniques covered include forward and reverse genetics [4], gene knockouts [5], conditional mutagenesis [6], RNA interference (RNAi) [7], pronuclear injection-based targeted transgenesis (PITT) [8], and CRISPR-Cas9 [9]. $ = low cost, $$ = moderate cost, $$$ = high cost based on technical complexity and resource needs.

Figure 2

Stages of Atheroma Formation. Atherosclerosis develops in sequential stages, starting from endothelial dysfunction to plaque rupture. Healthy Artery: The endothelium functions to maintain minimal inflammation, balance lipid levels, and a healthy vascular environment. Lesion Initiation: Endothelial cells (ECs), which line the blood vessel walls, lose their integrity, leading to increased vasoconstriction, lipid infiltration, leukocyte adhesion, and oxidative stress. The reduced bioavailability of nitric oxide (NO), a key vasoprotective molecule, is a hallmark of endothelial dysfunction. This stage sets the foundation for plaque development. Fatty Streak: Pro-atherogenic mediators, such as cytokines and adhesion molecules, recruit monocytes to the intima. These monocytes differentiate into macrophages, internalizing low-density lipoproteins (LDL) and forming foam cells, initiating fatty streak formation. Fibrous Plaque: A fibrous cap forms over the necrotic core, composed of collagen and other extracellular matrix (ECM) components, stabilizing the plaque. However, the fibrous cap can weaken due to vascular smooth muscle cell (VSMC) apoptosis and the release of matrix metalloproteinases. Plaque Rupture: When the fibrous cap ruptures due to hemodynamic forces, platelets aggregate, and a coagulation cascade leads to thrombus formation. This exacerbates the plaque, potentially obstructing blood flow and contributing to cardiovascular disease. Servier Medical Art was used to create the figure, which is licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), assessed on January 30 2023.

Figure 3

Direct effect of HIV on endothelial dysfunction. (A) HIV binds to the CD4 receptor on the surface of a T cell, fuses with the T cell, and replicates inside the T cell, HIV-secreted viral proteins, such as Nef and Tat, leading to the upregulation of adhesion molecules like ICAM-1 and VCAM-1. Additionally, immune cells secrete pro-inflammatory cytokines and chemokines, including IL-1α, IL-1β, IL-6, TNF-α, and NF-κB, further contributing to endothelial dysfunction. This dysfunction results in pathological outcomes such as vasoconstriction, lipid infiltration, leukocyte adhesion, oxidative stress, and cell death. (B) Chronic inflammation begins when a virus recognized by the T-cell receptor (TCR) causes T-cell death. These dead cells produce more pro-inflammatory cytokines, increasing reactive oxygen species (ROS) and oxidative stress. In endothelial cells, the early stages of atherosclerosis are marked by LDL entering the blood vessel wall, which becomes oxidized and induces monocyte recruitment. Recruited monocytes differentiate into macrophages, taking up oxLDL via scavenger receptors. This scavenger-receptor-mediated uptake of lipoproteins by macrophages leads to the formation of foam cells. (C) ART is a class of medications that suppress viral replication in HIV infections. As a side effect, some inhibitors can cause an imbalance between LDL and HDL levels, increase ROS production, and disrupt the body’s ability to neutralize this production damaging molecules. This results in more oxidative stress, increased oxLDL, the formation of more foam cells, and promotion of plaque formation. Created with BioRender.com, accessed 19 February 2025.

Figure 4

HIV life cycle, viral inhibitors, and ASCVD-associated mechanisms. (Left Panel) This figure illustrates the stages of the HIV life cycle, including binding and post-attachment, viral entry, reverse transcription, integration, transcription, translation, and budding. It also highlights the points at which various classes of antiretroviral drugs act to disrupt the viral replication process, including binding inhibitors (CCR4 antagonist), entry inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), integrase strand transfer inhibitors (INSTIs), protease inhibitors (PIs), and capsid inhibitors. (Right Panel) Among these viral inhibitors, CCR4 antagonists, post-attachment, fusion, and capsid inhibitors are atheroprotective. In contrast, nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), integrase strand transfer inhibitors (INSTIs), and protease inhibitors (PIs) may be atherogenic. Created with BioRender.com, accessed on 28 January 2025.

Figure 6

NSG-mouse models in CVD research related to HIV. On the (left), using NSG-MHC I/II double knock-out (DKO) mice reconstituted with PBMCs, the role of immune cells may be explored in the development stages of atherosclerosis. Due to the short-lived period, T cell functions will likely be better explored in this model. On the (right), we propose that NSG mice reconstituted with human stem cells modified to express HIV proteins, like Tg26 mice, would be used. We propose knocking out the LDL receptor for both models because the cholesterol profile is like humans versus a gain of function PCSK9 mouse, which can be performed using an adenoviral vector [105]. Created with BioRender.com, accessed on 16 February 2025.