Stem cell therapy targets the neointimal smooth muscle cells in experimentally induced atherosclerosis: involvement of intracellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM)

Hepatocyte growth factor enhances the ability of dental pulp stem cells to ameliorate atherosclerosis in apolipoprotein E-knockout mice

BACKGROUND

Atherosclerosis (AS), a chronic inflammatory disease of blood vessels, is a major contributor to cardiovascular disease. Dental pulp stem cells (DPSCs) are capable of exerting immunomodulatory and anti-inflammatory effects by secreting cytokines and exosomes and are widely used to treat autoimmune and inflammation-related diseases. Hepatocyte growth factor (HGF) is a pleiotropic cytokine that plays a key role in many inflammatory and autoimmune diseases.

AIM

To modify DPSCs with HGF (DPSC-HGF) and evaluate the therapeutic effect of DPSC-HGF on AS using an apolipoprotein E-knockout (ApoE-/-) mouse model and an in vitro cellular model.

METHODS

ApoE-/- mice were fed with a high-fat diet (HFD) for 12 wk and injected with DPSC-HGF or Ad-Null modified DPSCs (DPSC-Null) through tail vein at weeks 4, 7, and 11, respectively, and the therapeutic efficacy and mechanisms were analyzed by histopathology, flow cytometry, lipid and glucose measurements, real-time reverse transcription polymerase chain reaction (RT-PCR), and enzyme-linked immunosorbent assay at the different time points of the experiment. An in vitro inflammatory cell model was established by using RAW264.7 cells and human aortic endothelial cells (HAOECs), and indirect co-cultured with supernatant of DPSC-Null (DPSC-Null-CM) or DPSC-HGF-CM, and the effect and mechanisms were analyzed by flow cytometry, RT-PCR and western blot. Nuclear factor-κB (NF-κB) activators and inhibitors were also used to validate the related signaling pathways.

RESULTS

DPSC-Null and DPSC-HGF treatments decreased the area of atherosclerotic plaques and reduced the expression of inflammatory factors, and the percentage of macrophages in the aorta, and DPSC-HGF treatment had more pronounced effects. DPSCs treatment had no effect on serum lipoprotein levels. The FACS results showed that DPSCs treatment reduced the percentages of monocytes, neutrophils, and M1 macrophages in the peripheral blood and spleen. DPSC-Null-CM and DPSC-HGF-CM reduced adhesion molecule expression in tumor necrosis factor-α stimulated HAOECs and regulated M1 polarization and inflammatory factor expression in lipopolysaccharide-induced RAW264.7 cells by inhibiting the NF-κB signaling pathway.

CONCLUSION

This study suggested that DPSC-HGF could more effectively ameliorate AS in ApoE-/- mice on a HFD, and could be of greater value in stem cell-based treatments for AS.

Lycopene alleviates oxidative stress-induced cell injury in human vascular endothelial cells by encouraging the SIRT1/Nrf2/HO-1 pathway

BACKGROUND AND OBJECTIVE

Epidemiological research have displayed that dietary intake rich in lycopene, an antioxidant, is negatively correlated with the risk of cardiovascular disease (CVD). This study aimed to investigate whether the intervention with different concentrations of lycopene could attenuate H₂O₂-induced oxidative stress injury in human vascular endothelial cells (VECs).

METHODS

The human VECs HMEC-1 and ECV-304 were incubated with a final concentration of 300 µmol/L H₂O₂, followed by they were incubated with lycopene at doses of 0.5, 1, or 2 µm. Subsequently, cell proliferation, cytotoxicity, cell adhesion, reactive oxygen species (ROS) contents, adhesion molecule expression, oxidative stress levels, pro-inflammatory factor production, the apoptosis protein levels, and the silent information regulator-1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway protein levels were tested by CCK-8 kit, lactate dehydrogenase (LDH) kit, immunofluorescence labeling, cell surface enzyme immunoassays (EIA), enzyme-linked immunosorbent assay (ELISA), as well as Western blot assays, respectively.

RESULTS

Under H₂O₂ stimulation, HMEC-1 and ECV-304 cell proliferation and the SIRT1/Nrf2/HO-1 pathway protein expression were significantly reduced, whereas cytotoxicity, apoptosis, cell adhesion molecule expression, pro-inflammatory and oxidative stress factors production were apparently encouraged, which were partially countered by lycopene intervention in a dose-dependent manner.

CONCLUSION

Lycopene alleviates H₂O₂-induced oxidative damage in human VECs by reducing intracellular ROS levels, inflammatory factor production, cell adhesiveness, and apoptosis rate under oxidative stress conditions through activation of the SIRT1/Nrf2/HO-1 pathway.

Correlation between stem cell molecular phenotype and atherosclerotic plaque neointima formation and analysis of stem cell signal pathways

Vascular stem cells exist in the three-layer structure of blood vessel walls and play an indispensable role in angiogenesis under physiological conditions and vascular remodeling under pathological conditions. Vascular stem cells are mostly quiescent, but can be activated in response to injury and participate in endothelial repair and neointima formation. Extensive studies have demonstrated the differentiation potential of stem/progenitor cells to repair endothelium and participate in neointima formation during vascular remodeling. The stem cell population has markers on the surface of the cells that can be used to identify this cell population. The main positive markers include Stem cell antigen-1 (Sca1), Sry-box transcription factor 10 (SOX10). Stromal cell antigen 1 (Stro-1) and Stem cell growth factor receptor kit (c-kit) are still controversial. Different parts of the vessel have different stem cell populations and multiple markers. In this review, we trace the role of vascular stem/progenitor cells in the progression of atherosclerosis and neointima formation, focusing on the expression of stem cell molecular markers that occur during neointima formation and vascular repair, as well as the molecular phenotypic changes that occur during differentiation of different stem cell types. To explore the correlation between stem cell molecular markers and atherosclerotic diseases and neointima formation, summarize the differential changes of molecular phenotype during the differentiation of stem cells into smooth muscle cells and endothelial cells, and further analyze the signaling pathways and molecular mechanisms of stem cells expressing different positive markers participating in intima formation and vascular repair. Summarizing the limitations of stem cells in the prevention and treatment of atherosclerotic diseases and the pressing issues that need to be addressed, we provide a feasible scheme for studying the signaling pathways of vascular stem cells involved in vascular diseases.

Comparison of Cell-based and Nanoparticle-based Therapeutics in Treating Atherosclerosis

Today, cardiovascular diseases are among the biggest public health threats worldwide. Atherosclerosis, a chronic inflammatory disease with complex aetiology and pathogenesis, predispose many of these conditions, including the high mortality rate-causing ischaemic heart disease and stroke. Nevertheless, despite the alarming prevalence and absolute death rate, established treatments for atherosclerosis are unsatisfactory in terms of efficacy, safety, and patient acceptance. The rapid advancement of technologies in healthcare research has paved new treatment approaches, namely cell-based and nanoparticle-based therapies, to overcome the limitations of conventional therapeutics. This paper examines the different facets of each approach, discusses their principles, strengths, and weaknesses, analyses the main targeted pathways and their contradictions, provides insights on current trends as well as highlights any unique mechanisms taken in recent years to combat the progression of atherosclerosis.

Knockdown of mesenchymal stem cell‑derived exosomal LOC100129516 suppresses the symptoms of atherosclerosis via upregulation of the PPARγ/LXRα/ABCA1 signaling pathway

Mesenchymal stem cell (MSC) therapy has potential applications in treating atherosclerosis and coronary heart disease (CAD). Previous studies have demonstrated that MSCs are the most preferable sources of therapeutic exosomes, which carry long non‑coding RNAs and participate in the progression of atherosclerosis. The results of our previous bioinformatics study demonstrated that the levels of LOC100129516 were significantly upregulated in peripheral blood mononuclear cells obtained from patients with CAD. However, the biological role of LOC100129516 in the development of atherosclerosis remains to be elucidated. In the present study, THP‑1 cells were treated with oxidized low‑density lipoproteins to induce foam cell formation in vitro. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to detect the levels of LOC100129516 in THP‑1 macrophage‑derived foam cells. In addition, an in vivo model of atherosclerosis was established using Apolipoprotein E (ApoE) knockout (ApoE‑/‑) mice. The results of the RT‑qPCR assays demonstrated that the levels of LOC100129516 were upregulated in THP‑1 macrophage‑derived foam cells. MSC‑derived exosomes were able to deliver small interfering (si)‑LOC100129516 to THP‑1 cells to reduce the levels of LOC100129516. Moreover, transfection of si‑LOC100129516 via exosomal delivery significantly decreased the levels of total cholesterol (TC), free cholesterol and cholesterol ester in THP‑1 macrophage‑derived foam cells. Exosomal‑mediated delivery of si‑LOC100129516 decreased TC levels and low‑density lipoprotein levels in the ApoE‑/‑ atherosclerosis mouse model. Mechanistically, exosomal‑mediated delivery of si‑LOC100129516 promoted cholesterol efflux by activating the peroxisome proliferator‑activated receptor γ (PPARγ)/liver X receptor α (LXRα)/phospholipid‑transporting ATPase ABCA1 (ABCA1) signaling pathway in vitro and in vivo. Collectively, these results suggested that exosomal‑mediated delivery of si‑LOC100129516, in which the exosomes were derived from MSCs, promoted cholesterol efflux and suppressed intracellular lipid accumulation, ultimately alleviating the progression of atherosclerosis via stimulation of the PPARγ/LXRα/ABCA1 signaling pathway.