Increased activity of extrinsic and intrinsic apoptosis pathways in different mononuclear cell types in HIV type 1-infected patients regardless of whether they are depleted in disease

MicroRNA-24-3p inhibition prevents cell growth of vascular smooth muscle cells by targeting Bcl-2-like protein 11

Numerous reports have shown that dysfunction of vascular smooth muscle cells (VSMCs) serves a critical function in the development of cardiovascular disease, including coronary heart disease (CHD). microRNAs (miRNAs/miRs) have been reported to play important roles in regulating the function of VSMCs. The present study aimed to determine the role of miR-24-3p in VSMCs and to uncover the underlying mechanism. The expression of miR-24-3p in the peripheral blood samples of CHD patients was measured by reverse transcription-quantitative (RT-q)PCR. It was found that the level of miR-24-3p in the peripheral blood of patients with CHD was significantly upregulated compared with that in healthy controls. A dual luciferase reporter assay was performed to determine whether Bcl-2-like protein 11 (Bcl-2L11) was a target gene of miR-24-3p, and it was identified that Bcl-2L11 was a direct target of miR-24-3p. The mRNA level and protein expression of Bcl-2L11 in the peripheral blood of patients with CHD were measured by RT-qPCR and western blotting, respectively. The findings suggested that Bcl-2L11 was downregulated in the peripheral blood of patients with CHD. In addition, it was found that downregulation of miR-24-3p suppressed VSMC proliferation and promoted VSMC apoptosis, while the effects of the miR-24-3p inhibitor on cell viability and apoptosis were reversed by Bcl-2L11-small interfering (si)RNA. Additionally, downregulation of miR-24-3p increased the levels of Bcl-2L11, caspase-3 and Bax, and decreased Bcl-2 expression in VSMCs; these changes were abolished by Bcl-2L11-siRNA. In conclusion, the aforementioned results indicated that miR-24-3p was an important regulator in VSMC proliferation and apoptosis by targeting Bcl-2L11, which suggested that miR-24-3p might be a potential therapeutic target for the treatment of CHD.

Caspase-1 Activity in CD4 T Cells Is Downregulated Following Antiretroviral Therapy for HIV-1 Infection

Both Caspase 1-induced cell death and Caspase 3-induced cell death were reported to be the causes of CD4⁺ T cell depletion in HIV infection. We measured by flow cytometry the expression of key proteins associated with pyroptosis (Caspase 1), apoptosis (Caspase 3, Caspase 8, Caspase 9), and immune activation in peripheral T cells. The percentages of CD4⁺ T cells that expressed Caspase 1 and Caspase 3 were significantly higher in untreated human immunodeficiency virus 1 (HIV-1) patients compared with healthy control (Caspase 1: 19.40% vs. 4.65%, p = .006; Caspase 3: 12.75% vs. 4.18%, p < .001). However, the percentages of Caspase 3 in CD8⁺ T cells increased significantly, while the percentages of Caspase 1 in CD8⁺ T cells did not change significantly (Caspase 1: 3.33% vs. 1.99%, p = .821; Caspase 3: 20.35% vs 4.74%, p < .001). The percentages of HLA-DR⁺ CD38⁺ CD8⁺ T cells were positively correlated with those of Caspase 1⁺ CD4⁺ T cells, but not with those of Caspase 3⁺ CD4⁺ T cells. After highly active antiretroviral therapy, the percentages of Caspase 1, but not of Caspase 3, -expressing CD4⁺ T cells decreased to a level comparable with those of healthy controls (Caspase 1: 6.05% vs. 4.65%, p = .514; Caspase 3: 9.67% vs. 4.18%, p < .001). Our study indicated that CD4⁺ T cells experience both pyroptosis and apoptosis, while CD8⁺ T cells undergo only apoptosis in HIV-1 infection. Pyroptosis, but not apoptosis, in CD4⁺ T cells may be inhibited by effective antiretroviral therapy.