Increased expression of IL-32 correlates with IFN-γ, Th1 and Tc1 in virologically suppressed HIV-1-infected patients

The regulation and potential role of interleukin-32 in tuberculous pleural effusion

The possible protective effect of interleukin-32 (IL-32) in Mycobacterium tuberculosis (Mtb) infection has been indicated. However, few studies have been focused on IL-32 in tuberculosis patients. Additionally, the regulation of IL-32 production has rarely been reported. In the present study, the production, regulation, and role of IL-32 in tuberculous pleurisy (TBP) were investigated. We found that the content of IL-32 in tuberculous pleural effusion (TPE) was higher than the level in the malignant pleural effusion and transudative pleural effusion. The level of IL-32 mRNA in pleural fluid mononuclear cells (PFMCs) was higher than that in peripheral blood mononuclear cells (PBMCs) of patients with TBP, and this difference was mainly reflected in the splice variants of IL-32α, IL-32β, and IL-32γ. Compared with the PBMCs, PFMCs featured higher IL-32β/IL-32γ and IL-32α/IL-32γ ratios. In addition, lipopolysaccharide (LPS), Bacillus Calmette-Guérin (BCG), and H37Ra stimulation could induce IL-32 production in the PFMCs. IL-32 production was positively correlated with the TNF-α, IFN-γ, and IL-1Ra levels in TPE, whereas IFN-γ, but not TNF-α or IL-1Ra, could induce the production of IL-32 in PFMCs. Furthermore, IL-32γ could induce the TNF-α production in PFMCs. Monocytes and macrophages were the main sources of IL-32 in PFMCs. Nevertheless, direct cell-cell contact between lymphocytes and monocytes/macrophages plays an important role in enhancing IL-32 production by monocyte/macrophage cells. Finally, compared with the non-tuberculous pleural effusion, the purified CD4+ and CD8+ T cells in TPE expressed higher levels of intracellular IL-32. Our results suggested that, as a potential biomarker, IL-32 may play an essential role in the protection against Mtb infection in patients with TBP. However, further studies need to be carried out to clarify the functions and mechanisms of the IFN-γ/IL-32/TNF-α axis in patients with TBP.

IL-32 and its Paradoxical Role in Neoplasia

Interleukin-32 (IL-32) is an interleukin cytokine usually linked to inflammation. In recent years, it has been found that IL-32 exhibits both pro- and anti-tumor effects. Although most of those effects from IL-32 appear to favor tumor growth, some isoforms have shown to favor tumor suppression. This suggests that the role of IL-32 in neoplasia is very complex. Thus, the role of IL-32 in these various cancers and protein pathways makes it a very crucial component to consider when looking at potential therapeutic options in tumor treatment. In this review, we will explore what is currently known about IL-32, including its relationship with tumorigenesis and the potential for IL-32 to enhance local and systemic anti-tumor immune responses. Such a study might be helpful to accelerate the development of IL-32-based immunotherapies.

Differential Impact of IL-32 Isoforms on the Functions of Coronary Artery Endothelial Cells: A Potential Link with Arterial Stiffness and Atherosclerosis

Chronic inflammation is associated with higher risk of cardiovascular disease (CVD) in people living with HIV (PLWH). We have previously shown that interleukin-32 (IL-32), a multi-isoform proinflammatory cytokine, is chronically upregulated in PLWH and is linked with CVD. However, the mechanistic role of the different IL-32 isoforms in CVD are yet to be identified. In this study, we aimed to investigate the potential impact of IL-32 isoforms on coronary artery endothelial cells (CAEC), whose dysfunction represents a major factor for atherosclerosis. Our results demonstrated that the predominantly expressed IL-32 isoforms (IL-32β and IL-32γ) have a selective impact on the production of the proinflammatory cytokine IL-6 by CAEC. Furthermore, these two isoforms induced endothelial cell dysfunction by upregulating the expression of the adhesion molecules ICAM-I and VCAM-I and the chemoattractants CCL-2, CXCL-8 and CXCL-1. IL-32-mediated expression of these chemokines was sufficient to drive monocyte transmigration in vitro. Finally, we demonstrate that IL-32 expression in both PLWH and controls correlates with the carotid artery stiffness, measured by the cumulated lateral translation. These results suggest a role for IL-32-mediated endothelial cell dysfunction in dysregulation of the blood vessel wall and that IL-32 may represent a therapeutic target to prevent CVD in PLWH.

Inhibitory and Stimulatory Effects of IL-32 on HIV-1 Infection

The proinflammatory cytokine IL-32 is elevated in the plasma and tissues of HIV-1–infected individuals. However, its significance in HIV-1 infection remains unclear because IL-32 inhibits and stimulates viral production in monocyte-derived macrophages (MDMs) and CD4+ T cells, respectively. In this study, we initially found that the inhibitory effect on human MDMs depends on SAMHD1, a dNTP triphosphohydrolase that inhibits viral reverse transcription. IL-32 increased the unphosphorylated active form of SAMHD1, which was consistent with the reduced expression of the upstream cyclin-dependent kinases. Indeed, IL-32 lost its anti–HIV-1 activity in MDMs when SAMHD1 was depleted. These results explain why IL-32 inhibits HIV-1 in MDMs but not CD4+ T cells, because SAMHD1 restricts HIV-1 in noncycling MDMs but not in cycling CD4+ T cells. Another unique feature of IL-32 is the induction of the immunosuppressive molecule IDO1, which is beneficial for HIV-1 infection. In this study, we found that IL-32 also upregulates other immunosuppressive molecules, including PD-L1, in MDMs. Moreover, IL-32 promoted the motility of MDMs, which potentially facilitates intercellular HIV-1 transmission. Our findings indicate that IL-32 has both the direct inhibitory effect on HIV-1 production in MDMs and the indirect stimulatory effects through phenotypic modulation of MDMs, and they suggest that the stimulatory effects may outweigh the inhibitory effect because the window for IL-32 to inhibit HIV-1 is relatively confined to SAMHD1-mediated reverse transcription suppression in the viral life cycle.

Altered T-Cell Subsets are Associated with Dysregulated Cytokine Secretion of CD4+ T Cells During HIV Infection

Background

CD4⁺ T cells play a critical role in the regulation of immunopathogenesis in HIV infection. Previous studies have shown contradictory results of the CD4⁺ T-cell responses in people living with HIV (PLHIV).

Methods

A cross-sectional study was performed on 40 healthy controls, 134 ART-naïve PLHIV, and 34 individuals who experienced 3-year ART with low baseline CD4 count from 4 August 2016 to 23 January 2019. We determined the frequencies of CD4⁺ T-cell subsets and described the cytokine secretion pattern of total and subsets of CD4⁺ T cells in these individuals.

Results

We found that CD4⁺ T cells in PLHIV displayed enhanced secretion of pro-inflammation cytokines and polyfunctionality due to HIV disease progression (r = -0.282, P = 0.0035 for IFN-γ; r = -0.412, P = 0.0002 for TNF-α; r = -0.243, P < 0.0001 for GM-CSF; r = -0.252, P = 0.0093 for IFN-γ⁺ TNF-α⁺ cells). However, the altered T-cell subsets, as presented by the loss of naïve cells and expansion of memory/effector population in PLHIV, were associated with discordant results in total and subsets of CD4⁺ T cells. As major cytokine-producing T subsets, effector/memory CD4 subsets showed impaired cytokine production (P < 0.05). We further demonstrated that 3-year ART treatment could improve CD4 counts by increasing the pool of naïve T cells but could not restore cytokine secretion in CD4⁺ T-cell subsets (P < 0.05).

Conclusion

These data identified the impaired capacity of cytokine secretion in CD4⁺ T-cell subsets due to HIV disease progression, and the altered T-cell subsets were associated with pseudo-elevation of cytokine production in total CD4⁺ T cells. This study collectively suggested the importance of therapies that can preserve and/or enhance the function of CD4⁺ T cells in strategies of HIV remission.

Overt IL-32 isoform expression at intestinal level during HIV-1 infection is negatively regulated by IL-17A

OBJECTIVES

Untreated HIV infection was previously associated with IL-32 overexpression in gut/intestinal epithelial cells (IEC). Here, we explored IL-32 isoform expression in the colon of people with HIV (PWH) receiving antiretroviral therapy (ART) and IL-32 triggers/modulators in IEC.

DESIGN

Sigmoid colon biopsies (SCB) and blood were collected from ART-treated PWH (HIV + ART; n = 17; mean age: 56 years; CD4+ cell counts: 679 cells/μl; time on ART: 72 months) and age-matched HIV-uninfected controls (HIVneg; n = 5). The IEC line HT-29 was used for mechanistic studies.

METHODS

Cells from SCB and blood were isolated by enzymatic digestion and/or gradient centrifugation. HT-29 cells were exposed to TLR1-9 agonists, TNF-α, IL-17A and HIV. IL-32α/β/γ/D/ε/θ and IL-17A mRNA levels were quantified by real-time RT-PCR. IL-32 protein levels were quantified by ELISA.

RESULTS

IL-32β/γ/ε isoform transcripts were detectable in the blood and SCB, with IL-32β mRNA levels being predominantly expressed in both compartments and at significantly higher levels in HIV + ART compared to HIVneg. IL-17A transcripts were only detectable in SCB, with increased IL-17A levels in HIVneg compared with HIV + ART and negatively correlated with IL-32β mRNA levels. IL-32β/γ/ε isoform mRNA were detected in HT-29 cells upon exposure to TNF-α, Poly I:C (TLR3 agonist), Flagellin (TLR-5 agonist) and HIV. IL-17A significantly decreased both IL-32 β/γ/ε mRNA and cell-associated IL-32 protein levels induced upon TNF-α and Poly I:C triggering.

CONCLUSION

We document IL-32 isoforms abundant in the colon of ART-treated PWH and reveal the capacity of the Th17 hallmark cytokine IL-17A to attenuate IL-32 overexpression in a model of inflamed IEC.

The Effect of JAK1/2 Inhibitors on HIV Reservoir Using Primary Lymphoid Cell Model of HIV Latency

HIV eradication is hindered by the existence of latent HIV reservoirs in CD4⁺ T cells. Therapeutic strategies targeting latent cells are required to achieve a functional cure, however the study of latently infected cells from HIV infected persons is extremely challenging due to the lack of biomarkers that uniquely characterize them. In this study, the dual reporter virus HIV_GKO was used to investigate latency establishment and maintenance in lymphoid-derived CD4⁺ T cells. Single cell technologies to evaluate protein expression, host gene expression, and HIV transcript expression were integrated to identify and analyze latently infected cells. FDA-approved, JAK1/2 inhibitors were tested in this system as a potential therapeutic strategy to target the latent reservoir. Latent and productively infected tonsillar CD4⁺ T cells displayed similar activation profiles as measured by expression of CD69, CD25, and HLADR, however latent cells showed higher CXCR5 expression 3 days post-infection. Single cell analysis revealed a small set of genes, including HIST1-related genes and the inflammatory cytokine, IL32, that were upregulated in latent compared to uninfected and productively infected cells suggesting a role for these molecular pathways in persistent HIV infection. In vitro treatment of HIV-infected CD4⁺ T cells with physiological concentrations of JAK1/2 inhibitors, ruxolitinib and baricitinib, used in clinical settings to target inflammation, reduced latent and productive infection events when added 24 hr after infection and blocked HIV reactivation from latent cells. Our methods using an established model of HIV latency and lymphoid-derived cells shed light on the biology of latency in a crucial anatomical site for HIV persistence and provides key insights about repurposing baricitinib or ruxolitinib to target the HIV reservoir.

Interleukin 32 Promotes Foxp3+ Treg Cell Development and CD8+ T Cell Function in Human Esophageal Squamous Cell Carcinoma Microenvironment

Proinflammatory cytokine interleukin 32 (IL-32) is involved in infectious diseases and cancer, but what subtypes of immune cells express IL-32 and its roles in tumor microenvironment (TME) have not been well discussed. In this study, we applied bioinformatics to analyze single-cell RNA sequencing data about tumor-infiltrating immune cells from esophageal squamous cell carcinoma (ESCC) TME and analyzed IL-32 expression in different immune cell types. We found CD4⁺ regulatory T cells (Treg cells) express the highest level of IL-32, while proliferating T and natural killer cells expressed relatively lower levels. Knocking down of IL-32 reduced Foxp3 and interferon gamma (IFNγ) expressions in CD4⁺ and CD8⁺ T cells, respectively. IL-32 was positively correlated with Foxp3, IFNG, and GZMB expression but was negatively correlated with proliferation score. IL-32 may have a contradictory role in the TME such as it promotes IFNγ expression in CD8⁺ T cells, which enhances the antitumor activity, but at the same time induces Foxp3 expression in CD4⁺ T cells, which suppresses the tumor immune response. Our results demonstrate different roles of IL-32 in Treg cells and CD8⁺ T cells and suggest that it can potentially be a target for ESCC cancer immunosuppressive therapy.

Alteration of type I interferon response is associated with subclinical atherosclerosis in virologically suppressed HIV-1-infected male patients

Given human immunodeficiency virus‐1 (HIV‐1)‐infected patients have alterations in the type I interferon (IFN‐I) pathway and are also at elevated risk of atherosclerosis, we evaluated IFN‐I response and subclinical cardiovascular disease (CVD) association in HIV‐1‐infected patients. Transcript levels of IFN‐α/β and IFN‐stimulated gene 56 (ISG56) were evaluated by RT/real‐time PCR in peripheral blood mononuclear cells collected from asymptomatic HIV‐1‐positive male patients at high risk of developing CVD (n = 34) and healthy subjects (n = 21). Stenosis degree (≥ or <50%), calcium volume score, calcium Agatston score, and myocardial extracellular volume were examined by coronary computerized tomography scan. Carotid intima‐media thickness (cIMT), Framingham risk score, atherosclerotic cardiovascular disease (ASCVD) score, and risk score developed by data collection on adverse effects of anti‐HIV drugs (D:A:D) were also measured. Increased IFN‐α, IFN‐β, and ISG56 levels were observed in all HIV‐1‐infected males compared to healthy controls (p < .001 for all genes analyzed). HIV‐1‐infected patients with a stenosis degree ≥50% showed a higher Framingham risk score (p = .019), which was correlated with IFN‐β and ISG56 levels. HIV‐1‐infected males with enhanced IFN‐I levels and stenosis displayed a higher ASCVD calculated risk (p = .011) and D:A:D score (p = .004). Also, there was a trend toward higher IFN‐α and ISG56 mRNA levels in HIV‐1‐positive patients with an increased cIMT (p > .05). Dysregulation of IFN‐I response might participate in the pathogenesis of HIV‐1‐associated CVD.

Analysis of type I IFN response and T cell activation in severe COVID-19/HIV-1 coinfection: A case report

RATIONALE

Complex immune dysregulation in interferon (IFN) and T cell response has been observed in human immunodeficiency virus (HIV-1)-infected patients as well as in coronavirus disease-2019 (COVID-19) patients. However, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)/HIV-1 coinfection has been described in only few cases worldwide and no data are available on immunological outcomes in HIV-1-patients infected with SARS-CoV-2. Hence, this study aims to compare type I IFN response and T cell activation levels between a SARS-CoV-2/HIV-1-coinfected female patient and age-matched HIV-1-positive or uninfected women.

PATIENT CONCERNS

A 52-year-old woman diagnosed with SARS-CoV-2/HIV-1 coinfection, ten HIV-1-positive women and five age-matched-healthy individuals were enrolled in this study.

DIAGNOSES

SARS-CoV-2 infection caused severe pneumonia in the second week of illness in HIV-1-positive patient under protease inhibitors. Chest high-resolution computed tomography images of the SARS-CoV-2/HIV-1-coinfected patient showed bilateral ground-glass opacities.

INTERVENTIONS

SARS-CoV-2/HIV-1-coinfected female patient under darunavir/cobicistat regimen received a 7-days hydroxychloroquine therapy. Analysis of IFNα/β mRNA levels and CD4 and CD8 T cell (CD38, human leukocyte antigen-DR [HLA-DR], CD38 HLA-DR) frequencies were performed by RT/real-time PCR assays and flow cytometry, respectively. Median relative difference (MRD) was calculated for each immunological variable. For values greater than reference, MRD should be a positive number and for values that are smaller, MRD should be negative.

OUTCOMES

The severe pneumonia observed in SARS-CoV-2/HIV-1-positive patient under protease inhibitors was reversed by a 7-days hydroxychloroquine therapy. At the end of treatment, on day 7, patient reported resolution of fever, normalization of respiratory rate (14 breaths/min), and improved oxygen arterial pressure with a FiO2 of 30%. MRD values for IFNα/β and CD4 and CD8 T cells expressing CD38 and/or HLA-DR found in SARS-CoV-2-/HIV-1-coinfected woman were approximatively equal to 0 when refereed respectively to HIV-1-positive female patients [MRDs IFNα/β: median -0.2545 (range: -0.5/0.1); T cells: median -0.11 (range: -0.8/1.3)] and ≥ 6 when referred to healthy individuals [MRDs IFNα/β: median 28.45 (range: 15/41.9); T cells: median 10 (range 6/22)].

LESSONS

These results indicate that SARS-CoV-2 infection in HIV-1-positive female patient was associated with increased levels of IFNα/β-mRNAs and T cell activation compared to healthy individuals.

Admission IL-32 concentration predicts severity and mortality of severe community-acquired pneumonia independently of etiology

BACKGROUND

Severe community-acquired pneumonia (SCAP) is a critical disorder with high morbidity and mortality, usually manifested as acute respiratory failure and septic shock generally caused by exaggerated systemic inflammation. Interleukin-32 (IL-32), a pro-inflammatory cytokine, has been reported involved in various infectious diseases. We investigated the efficacy of the plasma IL-32 as a biomarker for evaluating the severity and clinical outcomes in SCAP patients.

METHODS

A total of 124 adult immunocompetent SCAP patients and 87 healthy controls were enrolled in this observational, prospective cohort study.

RESULTS

We found that PBMCs IL-32 mRNA and plasma IL-32 concentrations on admission of SCAP patients were significantly higher than healthy controls. Plasma IL-32 concentrations closely correlated with increasing severity scores, the need for vasopressor support or invasive mechanical ventilation but not with the etiology. The area under the curve (AUC) for predicting 30-day mortality using IL-32 was 0.812, is superior to WBCs and CRP. Incorporation of IL-32 with the severity scores were shown to improve the prognostic accuracy considerably. Furthermore, the 30-day cumulative survival rate in high IL-32 concentration group was significantly lower than that in the low concentration group. In a multivariate Cox regression analysis, higher IL-32 concentration and higher PSI score were recognized as the independent risk factors for survival, and the relative risks were 2.568 and 3.362, respectively.

CONCLUSIONS

Admission IL-32 concentration closely related to the severity and mortality of SCAP, and it may be served as a potential biomarker to help clinical judgment and management.