Modulation of LPS-induced CD4+ T-cell activation and apoptosis by antioxidants in untreated asymptomatic HIV infected participants: an in vitro study

Euonymus alatus (Thunb.) Siebold leaf extract enhanced immunostimulatory effects in a cyclophosphamide-induced immunosuppressed rat model

Background

Euonymus alatus (Thunb.) Siebold (EA) is a medicinal plant used in some Asian countries to treat various diseases, including cancer, hyperglycemia, diabetes, urticaria, dysmenorrhea, and arthritis. Owing to the wide range of pharmacological applications of EA, various roles of EA are being studied.

Objective

We evaluated the immune-enhancing effect of EA treatment in a cyclophosphamide (Cy)-induced immunosuppressed rat model.

Design

We analyzed the immune enhancement effect of EA on macrophages by western blotting. In addition, cell viability and natural killer (NK) cell activity were analyzed in splenocytes following EA treatment. For in vivo studies, analysis of weekly body weight, spleen weight, immune cell count, cytokine levels, and spleen histological findings was performed following EA administration in Cy-induced immunocompromised rats.

Results

EA significantly increased cell viability and phospho-nuclear factor-kappa B and phospho-extracellular signal-regulated kinase protein levels in the macrophages. EA significantly increased NK cell activity in splenocytes compared with the control group. In Cy-induced immunosuppressed rats, EA administration increased spleen tissue weight and the contents of leukocytes, lymphocytes, granulocytes, intermediate cells, and plasma cytokines (tumor necrosis factor-α and interferon-γ). In addition, improvement in the damaged spleen tissue was observed.

Conclusions

These findings confirm that EA exerts an immune-enhancing effect, thereby suggesting its potential as an immunostimulatory agent or functional food.

Immune-Enhancing Effects of Co-treatment With Kalopanax pictus Nakai Bark and Nelumbo nucifera Gaertner Leaf Extract in a Cyclophosphamide-Induced Immunosuppressed Rat Model

Objective

Immune system disorders can result in various pathological conditions, such as infections and cancer. Identifying therapies that enhance the immune response might be crucial for immunocompromised individuals. Therefore, we assessed the immune-enhancing effect of co-treatment with Kalopanax pictus Nakai Bark and Nelumbo nucifera Gaertner leaf extract (KPNN) in a cyclophosphamide (Cy)-induced immunosuppressed rat model.

Materials and Methods

For in vitro studies, macrophages and splenocytes were treated with various KPNN doses in the presence or absence of Cy. Macrophage viability, nitric oxide production, splenocyte viability, cytokine production and natural killer (NK) cell activity were analyzed. For in vivo studies, analysis of weekly body weight, dietary intake, tissue weight, immune-related blood cell count, cytokine levels, and spleen biopsy was performed in a Cy-induced immunocompromised animal model.

Results

KPNN significantly increased phospho-NF-κB and phospho-ERK protein levels and cell viability in macrophages. KPNN significantly increased the NK cell activity in splenocytes compared to that in the control. Cy treatment decreased tumor necrosis factor (TNF)-α, interleukin (IL)-6, and interferon-γ production. In the Cy-induced immunosuppression rat model, KPNN-treated rats had significantly higher body weights and tissue weights than the Cy-treated rats. Additionally, KPNN treatment restored the immune-related factors, such as total leukocyte, lymphocyte, and intermediate cell contents, to their normal levels in the blood. The blood cytokines (TNF-α and IL-6) were increased, and spleen tissue damage was significantly alleviated.

Conclusions

Collectively, KPNN exerts an immune-enhancing effect suggesting their potential as an immunostimulatory agent or functional food.

Antiretroviral Therapy-Induced Dysregulation of Gene Expression and Lipid Metabolism in HIV+ Patients: Beneficial Role of Antioxidant Phytochemicals

Human immunodeficiency virus (HIV) infection has continued to be the subject of study since its discovery nearly 40 years ago. Significant advances in research and intake of antiretroviral therapy (ART) have slowed the progression and appearance of the disease symptoms and the incidence of concomitant diseases, which are the leading cause of death in HIV+ persons. However, the prolongation of ART is closely related to chronic degenerative diseases and pathologies caused by oxidative stress (OS) and alterations in lipid metabolism (increased cholesterol levels), both of which are conditions of ART. Therefore, recent research focuses on using natural therapies to diminish the effects of ART and HIV infection: regulating lipid metabolism and reducing OS status. The present review summarizes current information on OS and cholesterol metabolism in HIV+ persons and how the consumption of certain phytochemicals can modulate these. For this purpose, MEDLINE and SCOPUS databases were consulted to identify publications investigating HIV disease and natural therapies and their associated effects.

Immunostimulatory Effect of Zanthoxylum schinifolium-Based Complex Oil Prepared by Supercritical Fluid Extraction in Splenocytes and Cyclophosphamide-Induced Immunosuppressed Rats

Complex oil of Zanthoxylum schinifolium and Perilla frutescens seed (ZPCO) is used as a traditional medicine due to its pharmacological activities. The aim of this study was to investigate the immunostimulatory effect of ZPCO in isolated splenocytes as well as in an immunosuppressed rat model, which was generated via oral administration of cyclophosphamide. Notably, our results showed that ZPCO exerted an immunity-enhancing effect both in vitro and in vivo. Specifically, ZPCO treatment enhanced the viability and inflammatory cytokine production of splenocytes and NK cell activity in vitro. Moreover, this product improved host defense under immunosuppressive conditions by increasing the number of immune cells and promoting the expression of cytokines involved in immune responses. Our results suggest that complex oil including Z. schinifolium should be explored as a novel immunostimulatory agent that could potentially be used for therapeutic purposes or as an ingredient in functional foods.

FOXO3, IRF4, and xIAP Are Correlated with Immune Activation in HIV-1-Infected Men Who Have Sex with Men During Early HIV Infection

Forkhead box O (FOXO)1, FOXO3, interferon regulatory factor (IRF)4, X-linked inhibitor of apoptosis protein (xIAP), and E74-like factor (ELF)4 have been described as important regulators of T cell functions and differentiation. However, whether these molecules are associated with HIV-1 disease progression is still unknown. In this study, we showed that the levels of FOXO3, IRF4, and xIAP mRNA in rapid progressors (RPs) were significantly higher than in HIV-negative healthy controls (HCs). Moreover, FOXO3 expression was positively correlated with HIV-1 viral load and CD4⁺ T cell activation. Remarkably, increased CD4⁺ and CD8⁺ T cell activation was apparent in RPs compared with typical progressors and HCs. In addition, a profile of higher apoptosis, more CD8⁺ T_EM cells, and fewer CD4⁺ and CD8⁺ Naive T cells were observed in early HIV infection patients with low CD4⁺ T cell counts. Furthermore, in vitro, IRF4 and xIAP expression was enhanced in peripheral blood mononuclear cells from healthy people following T cell receptor stimulation. T cell activation was decreased by treatment with siRNA inhibiting FOXO3, IRF4, and xIAP. Our results show that significantly increased levels of FOXO3, IRF4, and xIAP mRNA in Chinese HIV-1-infected patients were related to T cell immune activation, implicating them as potential targets for developing new therapeutic avenues to slow down HIV-1 disease progression.

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.

The Parenteral Vitamin C Improves Sepsis and Sepsis-Induced Multiple Organ Dysfunction Syndrome via Preventing Cellular Immunosuppression

Cellular immunosuppression appears to be involved in sepsis and sepsis-induced multiple organ dysfunction syndrome (MODS). Recent evidence showed that parenteral vitamin C (Vit C) had the ability to attenuate sepsis and sepsis-induced MODS. Herein, we investigated the impact of parenteral Vit C on cellular immunosuppression and the therapeutic value in sepsis. Using cecal ligation and puncture (CLP), sepsis was induced in WT and Gulo-/- mice followed with 200 mg/Kg parenteral Vit C administration. The immunologic functions of CD4+CD25+ regulatory T cells (Tregs) and CD4+CD25- T cells, as well as the organ functions, were determined. Administration of parenteral Vit C per se markedly improved the outcome of sepsis and sepsis-induced MODS of WT and Gulo-/- mice. The negative immunoregulation of Tregs was inhibited, mainly including inhibiting the expression of forkhead helix transcription factor- (Foxp-) 3, cytotoxic T lymphocyte associated antigen- (CTLA-) 4, membrane associated transforming growth factor-β (TGF-βm+), and the secretion of inhibitory cytokines [including TGF-β and interleukin- (IL-) 10], as well as CD4+ T cells-mediated cellular immunosuppression which was improved by parenteral Vit C in WT and Gulo-/- septic mice. These results suggested that parenteral Vit C has the ability to improve the outcome of sepsis and sepsis-induced MODS and is associated with improvement in cellular immunosuppression.

Reactive Oxygen Species in HIV Infection

Reactive oxygen species (ROS) are a family of oxygen molecules with an unpaired electron and play an important role in homeostasis and pathogenesis. The reactive molecules modify lipids, proteins and nucleic acids, and modulate a wide range of cellular functions. The importance of ROS in infection has been established through clinical and in vitro studies. Here we review the role of oxidative stress in HIV pathogenesis, the impact of ROS on immune responses in HIV patients, and ROS-mediated regulation of HIV infection. Future studies on the interplay between ROS and HIV infection may offer a new strategy for prevention and treatment.

Gut microbiota associated with HIV infection is significantly enriched in bacteria tolerant to oxygen

Objectives

Gut microbiota modifications occurring during HIV infection have recently been associated with inflammation and microbial translocation. However, discrepancies between studies justified a comprehensive analysis performed on a large sample size.

Design and methods

In a case–control study, next-generation sequencing of the 16S rRNA gene was applied to the faecal microbiota of 31 HIV-infected patients, of whom 18 were treated with antiretroviral treatment (ART), compared with 27 healthy controls. 21 sera samples from HIV-infected patients and 7 sera samples from control participants were used to test the presence of 25 markers of inflammation and/or immune activation.

Results

Diversity was significantly reduced in HIV individuals when compared with controls and was not restored in the ART group. The relative abundance of several members of Ruminococcaceae such as Faecalibacterium prausnitzii was critically less abundant in the HIV-infected group and inversely correlated with inflammation/immune activation markers. Members of Enterobacteriaceae and Enterococcaceae were found to be enriched and positively correlated with these markers. There were significantly more aerotolerant species enriched in HIV samples (42/52 species, 80.8%) when compared with the control group (14/87 species, 16.1%; χ² test, p<10⁻⁵, conditional maximum-likelihood estimate (CMLE) OR=21.9).

Conclusions

Imbalance between aerobic and anaerobic flora observed in HIV faecal microbiota could be a consequence of the gut impairment classically observed in HIV infection via the production of oxygen. Overgrowth of proinflammatory aerobic species during HIV infection raises the question of antioxidant supplementation, such as vitamin C, E or N-acetylcysteine.

An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTB, our results demonstrate that prior to delivery there is a reduction of CD4+ regulatory T cells (Tregs) in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of IL10, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4+ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs (CD4+ and CD8+), effector CD8+ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II+ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface.

Translocation of microbes and changes of immunocytes in the gut of rapid- and slow-progressor Chinese rhesus macaques infected with SIVmac239

Human/simian immunodeficiency virus (HIV/SIV) infection can cause severe depletion of CD4(+) T cells in both plasma and mucosa; it also results in damage to the gut mucosa barrier, which makes the condition more conducive to microbial translocation. In this study, we used SIV-infected Chinese rhesus macaques to quantify the extent of microbial translocation and the function of immune cells in the entire gastrointestinal tract and to compare their differences between rapid and slow progressors. The results showed that in the slow progressors, microbial products translocated considerably and deeply into the lamina propria of the gut; the tissue macrophages had no significant differences compared with the rapid progressors, but there was a slightly higher percentage of mucosal CD8(+) T cells and a large amount of extracellular microbial products in the lamina propria of the intestinal mucosa of the slow progressors. The data suggested that although microbial translocation increased markedly, the mucosal macrophages and CD8(+) T cells were insufficient to clear the infiltrated microbes in the slow progressors. Also, therapies aimed at suppressing the translocation of microbial products in the mucosa could help to delay the progression of SIV disease.