IL-32, a proinflammatory cytokine in rheumatoid arthritis

A novel cell source for therapy of knee osteoarthritis using atelocollagen microsphere-adhered adipose-derived stem cells: Impact of synovial fluid exposure on cell activity

Introduction

Administration of adipose-derived stem cells (ADSCs) into the joint cavity has been shown to alleviate the symptoms of knee osteoarthritis (OA) by releasing exosomes and anti-inflammatory cytokines. However, the therapeutic effect of these cells is limited by their rapid disappearance after administration. Thus, it is necessary to prolong cell survival in the joint cavity. This study aimed to investigate the potential application of ADSCs adhered to atelocollagen microspheres (AMSs) for cell therapy of knee OA.

Methods

ADSCs were cultured for 2, 4, and 7 days in AMS suspension or adherent culture dishes. The supernatants were analyzed for IL-10 and exosome secretion via enzyme-linked immunosorbent assay and Nanosight. The effect of AMS was compared with that of adherent-cultured ADSCs (2D-cultured ADSCs) using transcriptome analysis. Moreover, the solubility of AMS and viability of ADSCs were evaluated using synovial fluid (SF) from patients with knee OA.

Results

Compared with 2D-cultured ADSCs, AMS-cultured ADSCs exhibited a significant increase in secretion of exosomes and IL-10, and the expression of several genes involved in extracellular matrix and immune regulation were altered. Furthermore, when AMS-cultured ADSCs were cultured in SF from knee OA patients to mimic the intra-articular environment, the SF dissolved the AMSs and released viable ADSCs. In addition, AMS-cultured ADSCs showed significantly higher long-term cell viability than 2D-cultured ADSCs.

Conclusion

Increased survival of AMS-adhered ADSCs was observed in the intra-articular environment, and AMSs were found to gradually dissipate. These results suggest that AMS-adhered ADSCs are promising source for cell therapy of knee OA.

The Role of α-Enolase on the Production of Interleukin (IL)-32 in Con A-Mediated Inflammation and Rheumatoid Arthritis (RA)

Interleukin (IL)-32 is produced by T lymphocytes, natural killer cells, monocytes, and epithelial cells. IL-32 induces the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, IL-1β, IL-6, and IL-8, and IL-32 expression is highly increased in rheumatoid arthritis (RA) patients. Enolase-1 (ENO1) is a glycolytic enzyme and the stimulation of ENO1 induces high levels of pro-inflammatory cytokines in concanavalin A (Con A)-activated peripheral blood mononuclear cells (PBMCs) and macrophages in RA patients. In addition, there are many reports that anti-ENO1 antibody is correlated with the disease progression of RA. It implies that ENO1 could regulate IL-32 production during inflammation related to the pathogenesis of RA. Therefore, we investigated the role of ENO1 in IL-32 production using Con A-activated PBMCs and RA PBMCs. IL-32 expression is increased by ENO1 stimulation using real-time PCR and ELISA. In addition, we confirmed that IL-32 production was decreased in Con A-activated PBMCs and RA PBMCs pre-treated with NF-κB or p38 MAPK pathway inhibitors. Taken together, these results suggest that ENO1 plays an important role in inflammation through the induction of IL-32 production by the activation of the NF-κB and p38 MAPK pathways.

Stimulated Human Umbilical Cord Mesenchymal Stem Cells Enhance the Osteogenesis and Cranial Bone Regeneration through IL-32 Mediated P38 Signaling Pathway

Objective

Our previous study found that it could significantly increase the expression of IL32 after stimulating the human umbilical cord mesenchymal stem cells (S-HuMSCs). However, its role on the osteogenesis and cranial bone regeneration is still largely unknown. Here, we investigated the possible mechanism of this effect. Material and Methods. A series of experiments, including single-cell sequencing, flow cytometry, quantitative real-time polymerase chain reaction, and western blotting, were carried out to evaluate the characteristic and adipogenic-osteogenic differentiation potential of IL-32 overexpression HuMSCs (IL-32highHuMSCs) through mediating the P38 signaling pathway. Moreover, a rat skull bone defect model was established and treated by directly injecting the IL-32highHuMSCs to conduct its role on the cranial bone regeneration.

Results

In total, it found that compared to HuMSCs, IL32 was significantly increased and promoted the osteogenic differentiation (lower expressions of PPARγ, Adiponectin, and C/EBPα, and increased expressions of RUNX2, ALP, BMP2, OPN, SP7, OCN, and DLX5) in the S-HuMSCs (P < 0.05). Meanwhile, the enhanced osteogenic differentiation of HuMSCs was recovered by IL-32 overexpression (IL-32highHuMSCs) through activating the P38 signaling pathway, like as the S-HuMSCs (P < 0.05). However, the osteogenic differentiation potential of IL-32highHuMSCs was significantly reversed by the P38 signaling pathway inhibitor SB203580 (P < 0.05). Additionally, the HuMSCs, S-HuMSCs, and IL-32highHuMSCs all presented adipogenic-osteogenic differentiation potential, with higher levels of CD73, CD90, and CD105, and lower CD14, CD34, and CD45 (P > 0.05). Furthermore, these findings were confirmed by the rat skull bone defect model, in which the cranial bone regeneration was more pronounced in the IL-32highHuMSCs treated group compared to those in the HuMSCs group, with higher expressions of RUNX2, ALP, BMP2, and DLX5 (P < 0.05).

Conclusion

We have confirmed that S-HuMSCs can enhance the osteogenesis and cranial bone regeneration through promoting IL-32-mediated P38 signaling pathway, which is proved that IL-32 may be a therapeutic target, or a biomarker for the treatment of cranial bone injuries.

Role of mitochondrial dysfunction in the pathogenesis of rheumatoid arthritis: Looking closely at fibroblast- like synoviocytes

Rheumatoid arthritis (RA) is a chronic, autoimmune, and inflammatory disease that primarily targets the joints, leading to cartilage and bone destruction.Fibroblast-like synoviocytes (FLS) are specialized cells of the synovial lining in the joint that plays a fundamental role in the development of RA. Particularly, FLS of RA patients (RA-FLS) in the joint exhibit specific characteristics like higher invading and immunogenic properties, hyperproliferation, and reduced apoptotic capacity, suggesting a dysfunctional mitochondrial pool in these cells. Mitochondria are emerging as a potential organelle that can decide cellular immunometabolism, invasion properties, and cell death. Accordingly, multiplestudies established that mitochondria are crucial in establishing RA. However, the underlying mechanism of impaired mitochondrial function in RA remains poorly understood. This review will provide an overview of the mitochondrial role in the progression of RA, specifically in the context of FLS biology. We will also outline how mitochondria-centric therapeutics can be achieved that would yield novel avenues of research in pathological mediation and prevention.

scGEM: Unveiling the Nested Tree-Structured Gene Co-Expressing Modules in Single Cell Transcriptome Data

BACKGROUND

Single-cell transcriptome analysis has fundamentally changed biological research by allowing higher-resolution computational analysis of individual cells and subsets of cell types. However, few methods have met the need to recognize and quantify the underlying cellular programs that determine the specialization and differentiation of the cell types.

METHODS

In this study, we present scGEM, a nested tree-structured nonparametric Bayesian model, to reveal the gene co-expression modules (GEMs) reflecting transcriptome processes in single cells.

RESULTS

We show that scGEM can discover shared and specialized transcriptome signals across different cell types using peripheral blood mononuclear single cells and early brain development single cells. scGEM outperformed other methods in perplexity and topic coherence (p < 0.001) on our simulation data. Larger datasets, deeper trees and pre-trained models are shown to be positively associated with better scGEM performance. The GEMs obtained from triple-negative breast cancer single cells exhibited better correlations with lymphocyte infiltration (p = 0.009) and the cell cycle (p < 0.001) than other methods in additional validation on the bulk RNAseq dataset.

CONCLUSIONS

Altogether, we demonstrate that scGEM can be used to model the hidden cellular functions of single cells, thereby unveiling the specialization and generalization of transcriptomic programs across different types of cells.

Human IL-32θA94V mutant attenuates monocyte-endothelial adhesion by suppressing the expression of ICAM-1 and VCAM-1 via binding to cell surface receptor integrin αVβ3 and αVβ6 in TNF-α-stimulated HUVECs

Interleukin-32 (IL-32), first reported in 2005, and its isoforms have been the subject of numerous studies investigating their functions in virus infection, cancer, and inflammation. IL-32θ, one of the IL-32 isoforms, has been shown to modulate cancer development and inflammatory responses. A recent study identified an IL-32θ mutant with a cytosine to thymine replacement at position 281 in breast cancer tissues. It means that alanine was also replaced to valine at position 94 in amino acid sequence (A94V). In this study, we investigated the cell surface receptors of IL-32θA94V and evaluated their effect on human umbilical vein endothelial cells (HUVECs). Recombinant human IL-32θA94V was expressed, isolated, and purified using Ni-NTA and IL-32 mAb (KU32-52)-coupled agarose columns. We observed that IL-32θA94V could bind to the integrins αVβ3 and αVβ6, suggesting that integrins act as cell surface receptors for IL-32θA94V. IL-32θA94V significantly attenuated monocyte-endothelial adhesion by inhibiting the expression of Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor (TNF)-α-stimulated HUVECs. IL-32θA94V also reduced the TNF-α-induced phosphorylation of protein kinase B (AKT) and c-jun N-terminal kinases (JNK) by inhibiting phosphorylation of focal adhesion kinase (FAK). Additionally, IL-32θA94V regulated the nuclear translocation of nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1), which are involved in ICAM-1 and VCAM-1 expression. Monocyte-endothelial adhesion mediated by ICAM-1 and VCAM-1 is an important early step in atherosclerosis, which is a major cause of cardiovascular disease. Our findings suggest that IL-32θA94V binds to the cell surface receptors, integrins αVβ3 and αVβ6, and attenuates monocyte-endothelial adhesion by suppressing the expression of ICAM-1 and VCAM-1 in TNF-α-stimulated HUVECs. These results demonstrate that IL-32θA94V can act as an anti-inflammatory cytokine in a chronic inflammatory disease such as atherosclerosis.

Interleukin-32 as a biomarker in rheumatic diseases: A narrative review

Interleukin-32 (IL-32) is an important cytokine involved in the innate and adaptive immune responses. The role of IL-32 has been studied in the context of various diseases. A growing body of research has investigated the role of IL-32 in rheumatic diseases including inflammatory arthritides (rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis) and connective tissue diseases (systemic lupus erythematosus, systemic sclerosis, granulomatosis and polyangiitis, and giant cell arteritis). IL-32 has been shown to play different roles according to the type of rheumatic diseases. Hence, the putative role of IL-32 as a biomarker is also different in each rheumatic disease: IL-32 could serve as a biomarker for disease activity in some diseases, whereas in other diseases it could be a biomarker for certain disease manifestations. In this narrative review, we summarize the associations between IL-32 and various rheumatic diseases and discuss the putative role of IL-32 as a biomarker in each disease.

Diverse and divergent functions of IL-32β and IL-32γ isoforms in the regulation of malignant pleural mesothelioma cell growth and the production of VEGF-A and CXCL8

In this study, we sought to elucidate the roles of the interleukin (IL)-32β and IL-32γ in mesothelioma cell growth, and vascular endothelial growth factor (VEGF)-A and C-X-C motif chemokine ligand 8 (CXCL8) expression. IL-32 elicited a growth-promoting effect against one of the six mesotheliomas lines and exerted diverse regulatory functions in VEGF-A and CXCL8 secretion from mesotheliomas stimulated with or without IL-17A. Retroviral-mediated transduction of mesothelioma lines with IL-32γ resulted in enhanced IL-32β expression, which facilitated or suppressed the in vitro growth, and VEGF-A and CXCL8 expression. Overexpressed IL-32β-augmented growth and VEGF-A and CXCL8 production were mainly mediated through the phosphatidylinositol-3 kinase (PI3K) signaling pathway. On the other hand, overexpressed IL-32β-deceased growth was mediated through mitogen-activated protein kinase (MAPK) pathway. NCI-H2373IL-32γ tumors grew faster than NCI-H2373Neo tumors in a xenograft model, which was associated with increased vascularity. These findings indicate that IL-32 are involved in the regulation of growth and angiogenic factor production in mesotheliomas.

Genetic Association between Polymorphisms of Interleukin-32 and Dilated Cardiomyopathy in Chinese Han Population

Background

Dilated cardiomyopathy is a primary myocardial disease and one of the critical causes of heart failure. It is the most common indication for heart transplantation worldwide, and most idiopathic dilated cardiomyopathies are sporadic and multifactorial. Evidence has supported that several inflammatory cytokines and immune responses are involved in its pathological process. Interleukin-32 is a proinflammatory cytokine and is elevated during the worsening cardiac function. Herein, we evaluated the correlation between interleukin-32 gene polymorphisms (rs12934561 and rs28372698) and the susceptibility to dilated cardiomyopathy.

Methods

We enrolled 418 dilated cardiomyopathy patients and 437 healthy controls. The polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping the two single-nucleotide polymorphisms (SNPs), and SPSS software was used for statistical analyses.

Results

The C allele and CC genotype frequencies of rs12934561 were remarkably elevated in dilated cardiomyopathy patients compared to controls (both P < 0.001). The A allele and AA genotype frequencies of rs28372698 significantly decreased in dilated cardiomyopathy patients (P = 0.004 and P = 0.02, respectively). Compared to TT/TC genotype carriers of rs12934561, CC homozygotes presented an increased risk of dilated cardiomyopathy when the left ventricular ejection fraction no more than 30% (P = 0.02).

Conclusions

The IL-32 gene polymorphisms might implicate in DCM risk in the Chinese Han population, and rs12934561 could be a potential forecasting factor for screening high-risk population for DCM.

Clinical implications of interleukins-31, 32, and 33 in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common malignancies in China with a high morbidity and mortality.

AIM

To determine whether interleukin (IL)-31, IL-32, and IL-33 can be used as biomarkers for the detection of GC, via evaluating the correlations between their expression and clinicopathological parameters of GC patients.

METHODS

Tissue array (n = 180) gastric specimens were utilised. IL-31, IL-32, and IL-33 expression in GC and non-GC tissues was detected immunohistochemically. The correlations between IL-31, IL-32, and IL-33 expression in GC and severity of clinicopathological parameters were evaluated. Survival curves were plotted using the Kaplan-Meier method/Cox regression. Circulating IL-31, IL-32, and IL-33 were detected by ELISA.

RESULTS

We found that the expression levels of IL-31, IL-32, and IL-33 were all lower in GC than in adjacent non-GC gastric tissues (P < 0.05). IL-33 in peripheral blood of GC patients was significantly lower than that of healthy individuals (1.50 ± 1.11 vs 9.61 ± 8.00 ng/mL, P <0.05). Decreased IL-31, IL-32, and IL-33 in GC were observed in younger patients (< 60 years), and IL-32 and IL-33 were lower in female patients (P < 0.05). Higher IL-32 correlated with a longer survival in two GC subgroups: T4 invasion depth and TNM I-II stage. Univariate/multivariate analysis revealed that IL-32 was an independent prognostic factor for GC in the T4 stage subgroup. Circulating IL-33 was significantly lower in GC patients at TNM stage IV than in healthy people (P < 0.05).

CONCLUSION

Our findings may provide new insights into the roles of IL-31, IL-32, and IL-33 in the carcinogenesis of GC and demonstrate their relative usefulness as prognostic markers for GC. The underlying mechanism of IL-31, IL-32, and IL-33 actions in GC should be further explored.

A Critical Overview of Interleukin 32 in Leishmaniases

Interleukin-32 (IL-32) has several immune regulatory properties, which have driven its investigation in the context of various diseases. IL-32 expression is reported to be induced in the lesions of patients with American tegumentary leishmaniasis (ATL) by the New World Leishmania spp. that are responsible for causing ATL and visceral leishmaniasis (VL). IL-32 expression may elevate the inflammatory process through the induction of pro-inflammatory cytokines and also via mechanisms directed to kill the parasites. The genetic variants of IL-32 might be associated with the resistance or susceptibility to ATL, while different isoforms of IL-32 could be associated with distinct T helper lymphocyte profiles. IL-32 also determines the transcriptional profile in the bone marrow progenitor cells to mediate the trained immunity induced by β-glucan and BCG, thereby contributing to the resistance against Leishmania. IL-32γ is essential for the vitamin D-dependent microbicidal pathway for parasite control. In this context, the present review report briefly discusses the data retrieved from the studies conducted on IL-32 in leishmaniasis in humans and mice to highlight the current challenges to understanding the role of IL-32 in leishmaniasis.

Assessment of interleukin 32 as a novel biomarker for non-alcoholic fatty liver disease

Background

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder characterised by enhanced hepatic fat deposition and inflammation. Efforts to manage NAFLD are limited by the poorly characterised pathological processes and the lack of precise non-invasive markers, thus, proving the need to further study the involved cytokines, which, in turn, may represent novel molecular targets with possible diagnostic and therapeutic applications. Hence, we aimed to assess the diagnostic utility of serum interleukin 32 (IL-32) in NAFLD cases. This case-control study included 40 NAFLD patients and 40 healthy controls. The serum IL-32 concentrations were assessed by the enzyme-linked immunosorbent assay (ELISA).

Results

The serum IL-32 concentrations were significantly higher in NAFLD cases than controls (76 [45.5–111.125] vs. 13 [8–15] pg/mL, P < 0.001, respectively). IL-32 at a cut-off point > 22.5 pg/mL had 100% sensitivity, 87.50% specificity, 88.9% positive predictive value, 100% negative predictive value, and 98.2% accuracy in detecting the NAFLD cases.

Conclusion

Serum IL-32 could be considered a novel non-invasive marker for NAFLD. Further investigations are warranted to verify the potential utility of IL-32 in the clinical setting.

Comparison of the Seven Interleukin-32 Isoforms’ Biological Activities: IL-32θ Possesses the Most Dominant Biological Activity

Cytokines are significantly associated with the homeostasis of immune responses in health and disease. Interleukin-32 (IL-32) is a cytokine originally discovered in natural killer cell transcript 4. IL-32 with different disorders has been described in terms of pathogenesis and the progression of diseases. Clinical studies have investigated IL-32 under various conditions, such as viral infection, autoimmune diseases, inflammatory diseases, certain types of cancer, vascular disease, and pulmonary diseases. The high expression of IL-32 was identified in different tissues with various diseases and found to have multiple transcripts of up to seven isoforms. However, the purification and biological activities of these isoforms have not been investigated yet. Therefore, in this study, we purified and compared the biological activity of recombinant IL-32 (rIL-32) isoforms. This is the first time for seven rIL-32 isoforms (α, β, δ, γ, ϵ, ζ, and θ) to be cloned and purified using an Escherichia coli expression system. Next, we evaluate the biological activities of these seven rIL-32 isoforms, which were used to treat different types of cells by assessing the levels of inflammatory cytokine production. The results revealed that rIL-32θ possessed the most dominant biological activity in both immune and non-immune cells.

Interleukin-32γ in the Control of Acute Experimental Chagas Disease

Chagas disease (CD) is an important parasitic disease caused by Trypanosoma cruzi. Interleukin-32 (IL-32) plays an important role in inflammation and in the development of Th1/Th17 acquired immune responses. We evaluated the influence of IL-32γ on the immune response profile, pathogenesis of myocarditis in acute experimental CD, and control of the disease. For this, C57BL/6 wild-type (WT) and IL-32γTg mice were infected subcutaneously with 1,000 forms of Colombian strain of T. cruzi. In the histopathological analyzes, T. cruzi nests, myocarditis, and collagen were quantified in cardiac tissue. Cytokine productions (IL-32, IFN-γ, TNF-α, IL-10, and IL-17) were measured in cardiac homogenate by ELISA. The IL-32γTg mice showed a better control of parasitemia and T. cruzi nests in the heart than WT mice. Infected-WT and -IL-32γTg mice showed similar levels of IFN-γ, TNF-α, and IL-17, but IL-10 was significantly higher expressed in IL-32γTg than in WT mice. The cytokine profile found in IL-32γTg animals contributed to body weight maintenance, parasitemia control, and survival. Our results indicate that the presence of human IL-32γ in mice infected with the Colombian strain of T. cruzi is important for infection control during the acute phase of Chagas disease.

The Role of Interleukins in the Pathogenesis of Dermatological Immune-Mediated Diseases

Autoimmune inflammatory diseases are primarily characterized by deregulated expression of cytokines, which drive pathogenesis of these diseases. A number of approved and experimental therapies utilize monoclonal antibodies against cytokine proteins. Cytokines can be classified into different families including the interleukins, which are secreted and act on leukocytes, the tumor necrosis factor (TNF) family, as well as chemokine proteins. In this review article, we focus on the interleukin family of cytokines, of which 39 members have been identified to this date. We outline the role of each of these interleukins in the immune system, and various dermatological inflammatory diseases with a focused discussion on the pathogenesis of psoriasis and atopic dermatitis. In addition, we describe the roles of various interleukins in psychiatric, cardiovascular, and gastrointestinal comorbidities. Finally, we review clinical efficacy and safety data from emerging late-phase anti-interleukin therapies under development for psoriasis and atopic dermatitis. Collectively, additional fundamental and clinical research remains necessary to fully elucidate the roles of various interleukin proteins in the pathogenesis of inflammatory dermatologic diseases, and treatment outcomes in patients.

Anti-inflammatory natural products as potential therapeutic agents of rheumatoid arthritis: A systematic review

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease causing severe locomotor disability and deterioration in the quality of life. Existing treatments for RA mainly focus on the use of immunomodulators and the suppression of synovial inflammation, and many have significant side effects. Medicinal plants are regarded as important alternative sources for treating RA.

PURPOSE

This review summarizes the bioactive compounds of medicinal plants, which have been shown to modulate the immune response by regulating interleukins in vitro and in vivo experimental models, and that may be promising substances for use in the treatment of RA.

METHODS

Articles on natural products used for the management of arthritis were retrieved from PubMed, Embase, Scopus, and Web of Science through electronic and manual search in English. In total, 576 publications were identified, and 34 were included in this systematic review.

RESULTS

Two articles presented findings on the role of natural components in the treatment of arthritis in both in vitro and in vivo studies. Nine reports defined the role of plant-derived natural molecules in the treatment of arthritis using cell lines, and 27 in vivo studies assessed the anti-arthritic efficacy and immunomodulation effects of phytoconstituents on interleukin production and inflammatory responses.

CONCLUSION

This systematic review broadly reports that, in contrast to other classes of phytochemicals, flavonoids have the greatest therapeutic potential against arthritis by modulating the expression of pro-inflammatory TNF-α, IL-1β, IL-6, IL-8, and IL-17, as well as anti-inflammatory IL-2 and IL-10 cytokines, through the suppression of dynamic inflammatory biomarkers.

Molecular and Cellular Heterogeneity in Rheumatoid Arthritis: Mechanisms and Clinical Implications

Rheumatoid arthritis is an autoimmune disease that exhibits significant clinical heterogeneity. There are various treatments for rheumatoid arthritis, including disease-modifying anti-rheumatic drugs (DMARDs), glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), and inflammatory cytokine inhibitors (ICI), typically associated with differentiated clinical effects and characteristics. Personalized responsiveness is observed to the standard treatment due to the pathophysiological heterogeneity in rheumatoid arthritis, resulting in an overall poor prognosis. Understanding the role of individual variation in cellular and molecular mechanisms related to rheumatoid arthritis will considerably improve clinical care and patient outcomes. In this review, we discuss the source of pathophysiological heterogeneity derived from genetic, molecular, and cellular heterogeneity and their possible impact on precision medicine and personalized treatment of rheumatoid arthritis. We provide emphasized description of the heterogeneity derived from mast cells, monocyte cell, macrophage fibroblast-like synoviocytes and, interactions within immune cells and with inflammatory cytokines, as well as the potential as a new therapeutic target to develop a novel treatment approach. Finally, we summarize the latest clinical trials of treatment options for rheumatoid arthritis and provide a suggestive framework for implementing preclinical and clinical experimental results into clinical practice.

Protective immune response mediated by neutrophils in experimental visceral leishmaniasis is enhanced by IL-32γ

Neutrophils are important cells in protection against microbial infections including visceral leishmaniasis (VL). It is well known that IL-32γ increases the protective T helper 17 cell mediated immune response against Leishmania infantum. Thus, in this study we evaluated whether IL-32 γ can increase the protective role of neutrophils against VL. In comparison with wild type (WT) mice, transgenic mice for human IL-32 γ (IL-32 γ Tg) presented a higher frequency and absolute number of neutrophils in both spleen and liver after the establishment of L. infantum infection. The IL-32 concentrations correlated with neutrophil numbers in the infected tissues. The IL-32 γ -induced recruitment of neutrophils was dependent on IL-17, since inhibition of Th17 T cells generation and IL-17 production with digoxin treatment reversed the effects of IL-32 γ. In murine neutrophils, the presence of IL-32 γ enhanced the phagocytosis of L. infantum via CR3. In addition, murine IL-32 γ Tg neutrophils were able to kill L. infantum due to the increased production of ROS when compared with WT neutrophils. In fact, IL-32 γ Tg mice lost their ability to control infection by L. infantum when neutrophils were depleted. In parallel, treatment of human neutrophils with recombinant IL-32 γ increased phagocytosis and ROS-dependent killing of L. infantum, similarly to murine IL-32 γ Tg neutrophils. The data show that IL-32 γ induces neutrophil recruitment to organs affected by VL and increases phagocytosis and killing of L. infantum by neutrophils. Together, data indicate the pivotal axis IL-32 γ -Th17-neutrophils to control VL.

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.

Clinical Implications of IL-32, IL-34 and IL-37 in Atherosclerosis: Speculative Role in Cardiovascular Manifestations of COVID-19

Atherosclerosis, which is a primary cause of cardiovascular disease (CVD) deaths around the world, is a chronic inflammatory disease that is characterised by the accumulation of lipid plaques in the arterial wall, triggering inflammation that is regulated by cytokines/chemokines that mediate innate and adaptive immunity. This review focuses on IL-32, -34 and -37 in the stable vs. unstable plaques from atherosclerotic patients. Dysregulation of the novel cytokines IL-32, -34 and -37 has been discovered in atherosclerotic plaques. IL-32 and -34 are pro-atherogenic and associated with an unstable plaque phenotype; whereas IL-37 is anti-atherogenic and maintains plaque stability. It is speculated that these cytokines may contribute to the explanation for the increased occurrence of atherosclerotic plaque rupture seen in patients with COVID-19 infection. Understanding the roles of these cytokines in atherogenesis may provide future therapeutic perspectives, both in the management of unstable plaque and acute coronary syndrome, and may contribute to our understanding of the COVID-19 cytokine storm.

Impact of interleukin-32 germ-line rs28372698 and intronic rs12934561 polymorphisms on cancer development: A systematic review and meta-analysis

OBJECTIVE

The pro-inflammatory cytokine IL-32 has high susceptibility to develop cancer. But no previous meta-analysis was done to provide firm evidence. This systematic review and meta-analysis was designed to evaluate the association of IL-32 gene polymorphisms (rs28372698 and rs12934561) with cancer.

METHOD

Eligible studies were selected using authentic databases searching from January 2013 to January 2021. Demographic data and genotypic information were extracted and organized from the selected studies. Review Manager (RevMan) version 5.4 was used to perform data analysis and data arrangement for meta-analysis.

RESULTS

A total of seven studies with 3395 patients and 3781 controls were included in this study. IL-32 rs28372698 polymorphism implied that mutant allele (TT) carriers had a significantly higher risk of cancer (OR = 1.43, p = 0.032). Codominant 3, recessive and allele models also showed 1.36-, 1.38- and 1.11-fold increased risk, respectively (p < 0.05). Besides, the Asian population showed a significantly increased risk in codominant 2 (OR = 1.74), codominant 3 (OR = 1.78), recessive (OR = 1.76) and allele model (OR = 1.16). IL-32 rs12934561 showed significantly reduced cancer risk in codominant 1 (OR = 0.66. p = 0.035), codominant 2 (OR = 0.76, p = 0.007), and dominant model (OR = 0.72, p = 0.012). After subgroup analysis, an association of rs12934561 was found in Asians (codominant 1: OR = 0.54, p = 7.28 × 10^-8; codominant 2: OR = 1.40, p = 0.019; codominant 3: OR = 0.76, p = 0.0006; dominant model: OR = 0.64, p = 1.12 × 10^-5; overdominant model: OR = 0.64, p = 3.92 × 10^-7) but not in Caucasians. After stratifying with the control source, a significant (p < 0.05) association of rs28372698 and rs12934561 was found with cancer in population-based controls. No publication bias was found, and the outcome of this meta-analysis was not influenced by any individual study confirmed from sensitivity analysis. Moreover, trial sequential analysis (TSA) established a link between rs28372698 and rs12934561 polymorphisms and cancer.

CONCLUSION

The outcome of this meta-analysis revealed that IL-32 rs28372698 and rs12934561 polymorphisms are associated with cancer. Moreover, the Asian dynasty had a significant association compared to Caucasians.

Serum levels of IL-32 in patients with coronary artery disease and its relationship with the serum levels of IL-6 and TNF-α

The coronary artery disease (CAD) is a chronic inflammatory disease caused by atherosclerosis, in which arteries become clogged due to plaque formation, fat accumulation, and various sorts of immune cells. IL-32 is a proinflammatory cytokine, which enhances inflammation through inducing the secretion of different inflammatory cytokines. The main objective of the current study was to assess the serum levels of IL-32 in subjects with obstructive CAD and its relationship with the serum levels of IL-6 and TNF-α. This study was performed on 42 subjects with obstructive CAD and 42 subjects with non-obstructive CAD. The serum levels of TNF-α, IL-6, and IL-32 were measured using the enzyme-linked immunosorbent assay (ELISA). The serum levels of TNF-α, IL-6, and IL-32 were 3.2, 3.48, and 2.7 times higher in obstructive CAD compared to non-obstructive CAD, respectively. Moreover, the serum levels of TNF-α and IL-32 in obstructive CAD with cardiac arterial stenosis in one major vessel were significantly higher than the levels in obstructive CAD with cardiac arterial stenosis in more than one major vessel. ROC curve analysis revealed that the serum levels of TNF-α, IL-6, and IL-32 were good predictors of obstructive CAD. Moreover, multiple logistic regression analyses suggested that the serum levels of TNF-α, IL-6, IL-32, LDL, and ox-LDL were independently related to the presence of obstructive CAD, while serum levels of HDL were not. TNF-α, IL-32, and IL-6 showed an increase in obstructive CAD, and the serum levels of these cytokines showed a satisfactory ability for predicting obstructive CAD.

Interleukin-18 in Brazilian Rheumatoid Arthritis Patients: Can Leflunomide Reduce It?

OBJECTIVES

Rheumatoid arthritis affects about 1% of the world's population. This is a chronic autoimmune disease. It is predominant in females with progressive joint damage. Immune cells are involved, especially Th1/Th17 lymphocytes and their inflammatory cytokines. These proteins have different functions in the immune system, such as IL-16 is a chemotactic factor; IL-18 can activate NFκB transcription producing inflammatory proteins; IL-31 can activate the JAK/STAT pathway which leads to the production of inflammatory factors in chronic diseases; IL-33 promotes IL-16 secretion which causes lymphocyte recruitment, and IL-32 and IL-34 appear to increase TNF secretion by macrophages activation in AR. The aim of this study was to evaluate serum levels of IL-16, IL-18, IL-31, IL-32, IL-33, and IL-34 and compare them with the severity and treatment of RA patients if there are any correlations.

METHODS

A total of 140 RA patients and 40 healthy donors were recruited from the Department of Rheumatology at Hospital das Clínicas from the Federal University of Pernambuco. 60 AR patients were naïve for any treatment. Serum cytokine levels were determined using an ELISA kit.

RESULTS

Serum IL-16 (p = 0.0491), IL-18 (p < 0.0001), IL-31 (p = 0.0004), and IL-32 (p = 0.0040) levels were significantly increased in RA patients compared with healthy donors. It was observed that patients using leflunomide had the lowest IL-18 levels, close to controls levels (p = 0.0064).

CONCLUSION

IL-16, IL-18, IL-31, and IL-32 are increased in the serum of RA patients. IL-18 is at lower levels in those AR who are taking leflunomide as treatment.

The role of Interleukin-32 in autoimmunity

Interleukin-32 (IL-32) is a pro-inflammatory cytokine that induces other cytokines involved in inflammation, including tumour necrosis factor (TNF)-α, IL-6 and IL-1β. Recent evidence suggests that IL-32 has a crucial role in host defence against pathogens, as well as in the pathogenesis of chronic inflammation. Abnormal IL-32 expression has been linked to several autoimmune diseases, such as rheumatoid arthritis and inflammatory bowel diseases, and a recent study suggested the importance of IL-32 in the pathogenesis of type 1 diabetes. However, despite accumulating evidence, many molecular characteristics of this cytokine, including the secretory route and the receptor for IL-32, remain largely unknown. In addition, the IL-32 gene is found in higher mammals but not in rodents. In this review, we outline the current knowledge of IL-32 biological functions, properties, and its role in autoimmune diseases. We particularly highlight the role of IL-32 in rheumatoid arthritis and type 1 diabetes.

Interleukin 32: A novel player in perioperative neurocognitive disorders

Perioperative neurocognitive disorders (PND) are highly prevalent after surgery, especially in aged patients. PND results in long-term morbidity and mortality with unclear pathophysiologic mechanisms. As a key hallmark of PND, surgery-induced neuroinflammation resulted from the invading of exogenous tracers into the cerebral parenchyma, causing hippocampal neuroinflammation and cognitive impairment. IL-32, with different isoforms, played a significant regulatory role in various inflammatory diseases. Its prevalence in peripheral circulating blood was closely associated with the central nervous system (CNS) diseases. Beyond that, specific subtype of IL-32 was reported to involve in the neuroinflammation regulation in cerebral ischemia impairment, multiple sclerosis, Alzheimer's Disease, and so on. Thus, we speculate that IL-32 may participate in the regulation of the surgery-induced neuroinflammation during the parthenogenesis of PND. The isoforms, spatio-temporal regulation of IL-32 may determine its pro- or anti-inflammation properties in parthenogenesis of PND. Therefore, IL-32 could be a putative therapeutic target for the prevention and reversal of PND in the future.

Associations between Interleukin-32 Gene Polymorphisms rs12934561 and rs28372698 and Susceptibilities to Bladder Cancer and the Prognosis in Chinese Han Population

The proinflammatory chemokine interleukin-32 is related to various diseases, including cancer. However, it has never been associated with bladder cancer (BC). To detect whether there is a relationship between the IL-32 gene polymorphisms (rs12934561 C/T and rs28372698 T/A) and BC, the study enrolled 170 non-muscle-invasive bladder cancer (NMIBC) patients, 151 muscle-invasive bladder cancer (MIBC) patients, and 437 healthy controls. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used for the IL-32 single-nucleotide polymorphism (SNP) genotyping. Statistical analysis was performed using SNPstats online analysis software and SPSS software. Our data revealed that the CC homozygous genotype of rs12934561 in BC patients was significantly higher than that in controls (P = 0.03, OR = 1.47, 95%CI = 1.04‐2.08), and the percentage of TC genotype carriers was relatively less than that of controls (P = 0.001, OR = 0.61, 95%CI = 0.45‐0.82). Furthermore, the TT homozygous genotype of rs28372698 was associated with a significantly lower overall survival rate in MIBC patients (P = 0.028, OR = 2.77, 95%CI = 1.11‐6.90). The IL-32 gene polymorphism rs12934561 might be associated with increased BC risk, and the rs28372698 might participate in the prognosis of BC patients. Therefore, they could be potential forecasting factors for the prognosis of MIBC patients.

Natural Killer Cell Transcript 4 promotes the development of Sjӧgren's syndrome via activation of Rap1 on B cells

Autoimmune disorders are the third most common diseases in the United States, and affect the daily lives of millions of people. In this study, we analyzed patient samples, utilized a transgenic mouse model and human B cells to reveal Natural Killer Cell Transcript 4 (NK4) as a novel regulator that promotes the development of autoimmune disorders. NK4 was significantly elevated in samples from patients with Sjӧgren's Syndrome (SS). SS patients show elevated NK4 levels. There is a strong and positive correlation between the increased levels of NK4 and the duration of SS. Interestingly, transgenic expression of NK4 in a mouse model led to the development of autoantibodies and lymphocytic infiltration in salivary glands similar to those in SS patients. Those phenotypes were associated with increased B1a cells in the peritoneum, plasma cells in the spleen, and increased IgM, IgA, and IgG2a in serum of the NK4 transgenic mice. The autoimmune phenotypes became more severe in older mice. Moreover, after NK4 transfection, human naïve B cells were activated and memory B cells differentiation into IgG and IgA-plasmablasts, resulting in an increased production of autoantibodies.NK4 regulated the differentiation and activation of B cells through activating Rap1 activity. NK4 also promoted B cell migration in a paracrine fashion through an induction of CXCL13 in endothelial cells. Collectively, these findings identify NK4 as a promoter of the development of autoimmune disorders through its roles on B cells. Therefore, NK4 may be a novel therapeutic target for the treatment of autoimmune diseases.

Molecular interactions and functions of IL-32

IL-32 is a multifaceted cytokine associated with several diseases and inflammatory conditions. Its expression is induced in response to cellular stress such as hypoxia, infections, and pro-inflammatory cytokines. IL-32 can be secreted from cells and can induce the production of pro-inflammatory cytokines from several cell types but are also described to have anti-inflammatory functions. The intracellular form of IL-32 is shown to play an important role in various cellular processes, including the defense against intracellular bacteria and viruses and in modulation of cell metabolism. In this review, we discuss current literature on molecular interactions of IL-32 with other proteins. We also review data on the role of intracellular IL-32 as a metabolic regulator and its role in antimicrobial host defense.

Association between interleukin-32 polymorphisms and ovarian cancer in the Chinese Han population

Interleukin-32 (IL-32) as a pro-inflammatory cytokine participates in the progression of inflammation and cancer. Ovarian cancer (OC) accounts for a considerable mortality rate, but research on IL-32 and OC is almost nil. Our study aims to explore the association between IL-32 and the progression as well as prognosis of OC initially. This hospital-based case-control study enrolled 147 OC patients and 337 healthy controls, and we used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to distribute the genotypes. The results showed that the homozygous genotype (TT) of rs28372698 SNP was significantly higher in patients compared to controls (12.9% vs. 6.2%, P = 0.018, OR (95% CI) = 2.23 (1.16-4.29)). This revealed that TT genotype might be a risk factor in OC progression. This present study indicates that IL-32 gene polymorphism relates to an increased OC susceptibility, and IL-32 may be a marker for OC progression.

Interleukin-32 in Infection, Inflammation and Cancer Biology

Cytokines are small pleiotropic polypeptids secreted dominantly by the cells of the immune system. These polypeptids are main mediators of innate and acquired immunity, responsible for clonal expansion and differentiation of immune cells, initiation of immune response and enhancing of effector functions of leukocytes. Cytokine-related effects are most studied in the fields of inflammation, immunology, and cancer biology. In this review we discuss one of the most intriguing, recently discovered proinflammatory cytokine, interleukin 32.

Knockdown of IL-32 protects PC12 cells against oxygen-glucose deprivation/reoxygenation-induced injury via activation of Nrf2/NF-κB pathway

Cerebral ischemia/reperfusion injury (IRI) is one of major causes of ischemic organ damage. It is well established that inflammatory cytokines serve as regulatory factors in cerebral oxygen glucose deprivation/reoxygenation (OGD/R). However, the involving mechanism is not clear enough. OGD/R PC12 cells were used as a hypoxia/reoxygenation model. IL-32 expression and cell viability were detected by qRT-PCR and CCK-8 assay, respectively. Cell apoptosis were determined by flow cytometry and western blotting. Protein levels of inflammatory factors, and the activity of MPO, MDA and SOD were analyzed. Furthermore, western blot assay was carried out to assess protein levels of Nrf2, keap1, NQO-1, p-p65, p-IκBα, p65 and IκBα. The results revealed that IL-32 expression was significantly upregulated in PC12 cells induced by OGD/R. Nrf2, keap1 and NQO-1 level was reduced while phosphorylation level of p65 and IκBα was up-regulated in OGD/R-induced PC12 cells. Mechanism investigations found that IL-32 silence elevated the level of Nrf2, Keap1 and NQO-1, reduced p-p65 and p-IκBα level, and regulated the contents of TNF-a, IL-1β, IL-6 and MCP-1 in OGD/R PC12 cells. In addition, knockdown of IL-32 suppressed production of intracellular ROS, elevated SOD activity, reduced MPO and MDA content, and enhanced cell viability. Furthermore, cell apoptosis was induced in OGD/R PC12 cells with IL-32 silence. However, Nrf2 inhibitor reversed the effects of IL-32 knockdown on OGD/R PC12 cells. This research suggests that IL-32 silence may alleviate OGD/R and Nrf2 plays an important role in the protection by IL-32 silence on PC12 cells induced by OGD/R.

Early Detection of Peripheral Blood Cell Signature in Children Developing β-Cell Autoimmunity at a Young Age

The appearance of type 1 diabetes (T1D)-associated autoantibodies is the first and only measurable parameter to predict progression toward T1D in genetically susceptible individuals. However, autoantibodies indicate an active autoimmune reaction, wherein the immune tolerance is already broken. Therefore, there is a clear and urgent need for new biomarkers that predict the onset of the autoimmune reaction preceding autoantibody positivity or reflect progressive β-cell destruction. Here we report the mRNA sequencing-based analysis of 306 samples including fractionated samples of CD4⁺ and CD8⁺ T cells as well as CD4^-CD8^- cell fractions and unfractionated peripheral blood mononuclear cell samples longitudinally collected from seven children who developed β-cell autoimmunity (case subjects) at a young age and matched control subjects. We identified transcripts, including interleukin 32 (IL32), that were upregulated before T1D-associated autoantibodies appeared. Single-cell RNA sequencing studies revealed that high IL32 in case samples was contributed mainly by activated T cells and NK cells. Further, we showed that IL32 expression can be induced by a virus and cytokines in pancreatic islets and β-cells, respectively. The results provide a basis for early detection of aberrations in the immune system function before T1D and suggest a potential role for IL32 in the pathogenesis of T1D.

The proinflammatory cytokine TNFα induces DNA demethylation-dependent and -independent activation of interleukin-32 expression

IL-32 is a cytokine involved in proinflammatory immune responses to bacterial and viral infections. However, the role of epigenetic events in the regulation of IL-32 gene expression is understudied. Here we show that IL-32 is repressed by DNA methylation in HEK293 cells. Using ChIP sequencing, locus-specific methylation analysis, CRISPR/Cas9-mediated genome editing, and RT-qPCR (quantitative RT-PCR) and immunoblot assays, we found that short-term treatment (a few hours) with the proinflammatory cytokine tumor necrosis factor α (TNFα) activates IL-32 in a DNA demethylation-independent manner. In contrast, prolonged TNFα treatment (several days) induced DNA demethylation at the promoter and a CpG island in the IL-32 gene in a TET (ten-eleven translocation) family enzyme- and NF-κB-dependent manner. Notably, the hypomethylation status of transcriptional regulatory elements in IL-32 was maintained for a long time (several weeks), causing elevated IL-32 expression even in the absence of TNFα. Considering that IL-32 can, in turn, induce TNFα expression, we speculate that such feedforward events may contribute to the transition from an acute inflammatory response to chronic inflammation.

Treatment with maresin 1, a docosahexaenoic acid-derived pro-resolution lipid, protects skin from inflammation and oxidative stress caused by UVB irradiation

Acute exposure to UVB irradiation causes skin inflammation and oxidative stress, and long-term exposure to UVB irradiation may lead to carcinogenesis. Our organism has endogenous mechanisms to actively limit inflammation. Maresin 1 (MaR1; 7R,14S-dihydroxy-docosa-4Z,8E,10E,12Z,16Z,19Z-hexaenoic acid) is a pro-resolution lipid mediator derived from the docosahexaenoic acid, which presents anti-inflammatory and pro-resolution effects. However, it remains to be determined if treatment with MaR1 can inhibit inflammatory and oxidative alterations in the skin triggered by UVB. The treatment with MaR1 (0.1-10 ng/mice at -10 min relative to the UVB irradiation protocol) reduced UVB-induced skin edema, neutrophil recruitment (MPO; myeloperoxidase activity, and migration of LysM-eGFP⁺ cells), cytokine production, matrix metalloproteinase-9 activity, keratinocyte apoptosis, epidermal thickening, mast cells counts and degradation of skin collagen in hairless mice. UVB irradiation caused a decrease of GSH (reduced glutathione) levels, activity of the enzyme catalase, ferric reducing ability (FRAP), and ABTS radical scavenging capacity as well as induced lipid hydroperoxide, superoxide anion production, and gp91^phox mRNA expression. These parameters that indicate oxidative stress were inhibited by MaR1 treatment. Therefore, these data suggest MaR1 as a promising pharmacological tool in controlling the deleterious effects related to UVB irradiation.

Interferon-Beta Treatment Differentially Alters TLR2 and TLR4-Dependent Cytokine Production in Multiple Sclerosis Patients

OBJECTIVE

Multiple sclerosis (MS) is a multifactorial chronic disease that affects the central nervous system (CNS). Toll-like receptors (TLRs) play a central role in cytokine production after pathogen- and danger-associated molecular patterns (PAMPs and DAMPs) and contribute to CNS damage in MS patients. Here, we evaluated the effects of interferon (IFN)-β treatment in TLR2 and TLR4-dependent cytokine production and mRNA expression in whole-blood cell cultures from MS patients.

METHODS

We evaluated cytokine production by ELISA from whole-blood cell culture supernatants and mRNA expression by real-time polymerase chain reaction in peripheral blood mononuclear cells (PBMCs).

RESULTS

In patients treated with IFN-β, tumor necrosis factor (TNF)-α production after exposure to TLR2 agonist (Pam3Cys) was lower than in healthy controls and untreated MS patients. However, IFN-β treatment had no significant effect on TNF-α production after TLR4 agonist (LPS) stimulation. On the other hand, interleukin (IL)-10 production was increased in TLR4- but not in TLR2-stimulated whole-blood cell culture from MS patients under IFN-β treatment when compared to the controls. No differences in TNF-α or IL-10 mRNA expression in PBMCs from healthy controls and untreated or treated MS patients were detected, although PBMCs from treated patients presented higher levels of IL-32γ mRNA than those from controls.

CONCLUSIONS

Our data suggest that IFN-β treatment alters the TLR-dependent immune response of PBMCs from MS patients. This may contribute to the beneficial effects of IFN-β treatment.

Increased Human Interleukin-32 Expression Is Related to Disease Activity of Graves' Disease

Recently, abnormal expression of interleukin-32 (IL-32) has been involved in various inflammatory or autoimmune diseases, but the level of IL-32 expression in Graves' disease (GD) is still unknown. This study is aimed to explore the human IL-32 expression in GD and the association of IL-32 expression with the disease activity of GD. A total of 125 GD patients and 97 normal controls (NC) were recruited in this study. We examined IL-32 mRNA level in peripheral blood mononuclear cells (PBMCs) of 43 GD patients and 41 controls using real-time polymerase chain reaction (RT-PCR). Serum IL-32 level of 40 GD patients and 34 controls was measured by enzyme linked immunosorbent assay (ELISA). In another cohort including 42 GD patients and 22 controls, we detected the percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺T cells, and CD4^-IL-32α⁺ cells in PBMCs by flow cytometry. In GD patients, IL-32 mRNA expression was dramatically higher than that in controls (P < 0.001) and positively associated with FT3 (P = 0.036, r = 0.321). Subgroup analysis revealed that IL-32 mRNA level was elevated in both newly onset GD and refractory GD group (P < 0.01, P < 0.001, respectively) compared with controls. Furthermore, in refractory GD group, the IL-32 mRNA expression also positively correlated with FT3 (P = 0.019, r = 0.560). In addition, serum IL-32 level was notably higher in GD patients than that of controls (P < 0.01). Subgroup analysis also indicated that serum IL-32 level in both newly onset GD and refractory GD group was higher in comparison with controls (P = 0.015, P = 0.023, respectively) and serum IL-32 level in refractory GD patients positively correlated with TRAb (P = 0.043, r = 0.481). The percentages of IL-32α⁺ cells, CD4⁺IL-32α⁺ T cells, and CD4^-IL-32α⁺ cells were all significantly enhanced in GD patients compared with controls (P = 0.005, P = 0.017, P = 0.016, respectively). IL-32 and IL-32α⁺ cells may be associated with the pathogenesis of GD. IL-32 may become a promising target for the treatment of GD.

The Lipid Mediator Resolvin D1 Reduces the Skin Inflammation and Oxidative Stress Induced by UV Irradiation in Hairless Mice

UV irradiation-induced oxidative stress and inflammation contribute to the development of skin diseases. Therefore, targeting oxidative stress and inflammation might contribute to reduce skin diseases. Resolvin D1 (RvD1) is a bioactive metabolite generated during inflammation to actively orchestrate the resolution of inflammation. However, the therapeutic potential of RvD1 in UVB skin inflammation remains undetermined, which was, therefore, the aim of the present study. The intraperitoneal treatment with RvD1 (3-100 ng/mouse) reduced UVB irradiation-induced skin edema, myeloperoxidase activity, matrix metalloproteinase 9 activity, and reduced glutathione depletion with consistent effects observed with the dose of 30 ng/mouse, which was selected to the following experiments. RvD1 inhibited UVB reduction of catalase activity, and hydroperoxide formation, superoxide anion production, and gp91phox mRNA expression. RvD1 also increased the Nrf2 and its downstream targets NQO1 and HO-1 mRNA expression. Regarding cytokines, RvD1 inhibited UVB-induced production of IL-1β, IL-6, IL-33, TNF-α, TGF-β, and IL-10. These immuno-biochemical alterations by RvD1 treatment had as consequence the reduction of UVB-induced epidermal thickness, sunburn and mast cell counts, and collagen degradation. Therefore, RvD1 inhibited UVB-induced skin oxidative stress and inflammation, rendering this resolving lipid mediator as a promising therapeutic agent.

Monocytes in rheumatoid arthritis: Circulating precursors of macrophages and osteoclasts and, their heterogeneity and plasticity role in RA pathogenesis

Rheumatoid arthritis (RA) is a chronic systemic, autoimmune and inflammatory disease represented as synovitis, pannus formation, adjacent bone erosions, and joint destruction. The major cells involved in the perpetuation of RA pathogenesis are CD4⁺ T-cells (mainly Th1 cells and Th17 cells), fibroblasts like synoviocytes (FLS), macrophages and B cells. Other autoimmune cells such as dendritic cells, neutrophils, mast cells, and monocytes also contribute to RA pathogenesis. Monocytes are mainly bone marrow (BM) derived cells in the circulation. The chemokine receptors CCR2 and CX3CR1 expressed by monocytes interact with chemokine ligands CCL2 (MCP-1) and CX3CL1 (fractalkine) respectively produced by FLS and this interaction promotes their migration and recruitment into RA synovium. Activated monocytes on their surface exhibit upregulated antigenic expressions such as CD14, CD16, HLA-DR, toll-like receptors (TLRs), and adhesion molecules B1 and B2 integrins. RA monocytes interconnect with other cells in a positive loop manner in the propagation of the rheumatoid process. They skew towards mainly intermediate monocyte subsets (CD14⁺⁺ CD16⁺) which produce proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. Moreover, the predominant intermediate monocytes in RA differentiate into M1-macrophages which play a major role in synovial inflammation. Demonstrations suggest monocytes with CD14⁺ and CD16^- expression (classical monocytes?) differentiate to osteoclasts which are the cells responsible for bone erosion in RA synovial joints. Th17 cells induce the production of RANKL by FLS which promotes osteoclastogenesis. Cytokines mainly TNF-α, IL-1β, and IL-6 amplify osteoclastogenesis. Hence, monocytes are the circulating precursors of macrophages and osteoclasts in RA. AIM OF THE REVIEW: To enlighten the identity of monocytes, the antigenic expression on monocyte surface and their cytokines role in RA. We also emphasize about the chemokine receptors expressed by monocytes subsets and chemotaxis of circulating monocytes into RA synovium. Additionally, we review monocytes as the circulating precursors of macrophages and osteoclasts in RA joints and their heterogeneity and plasticity role in RA.

The Biology and Role of Interleukin-32 in Tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis, remains a leading cause of morbidity and mortality globally, with nearly 10.4 million new cases of incidence and over 1.7 million deaths annually. Drug-resistant M. tuberculosis strains, especially multidrug-resistant or extensively drug-resistant strains, have further intensified the problem associated with tuberculosis control. Host-directed therapy is a promising alternative for tuberculosis control. IL-32 is increasingly recognized as an important host molecule against tuberculosis. In this review, we highlight the proinflammatory properties of IL-32 and the mode of action of IL-32 in mycobacterial infections to inspire the development of novel immunity-based countermeasures and host-directed therapies against tuberculosis.

IL-32γ attenuates airway fibrosis by modulating the integrin-FAK signaling pathway in fibroblasts

Background

Fibrosis in severe asthma often leads to irreversible organ dysfunction. However, the mechanism that regulates fibrosis remains poorly understood. Interleukin (IL)-32 plays a role in several chronic inflammatory diseases, including severe asthma. In this study, we investigated whether IL-32 is involved in fibrosis progression in the lungs.

Methods

Murine models of chronic airway inflammation induced by ovalbumin and Aspergillus melleus protease and bleomycin-induced pulmonary fibrosis were employed. We evaluated the degree of tissue fibrosis after treatment with recombinant IL-32γ (rIL-32γ). Expression of fibronectin and α-smooth muscle actin (α-SMA) was examined and the transforming growth factor (TGF)-β-related signaling pathways was evaluated in activated human lung fibroblasts (MRC-5 cells) treated with rIL-32γ.

Results

rIL-32γ significantly attenuated collagen deposition and α-SMA production in both mouse models. rIL-32γ inhibited the production of fibronectin and α-SMA in MRC-5 cells stimulated with TGF-β. Additionally, rIL-32γ suppressed activation of the integrin-FAK-paxillin signaling axis but had no effect on the Smad and non-Smad signaling pathways. rIL-32γ localized outside of MRC-5 cells and inhibited the interaction between integrins and the extracellular matrix without directly binding to intracellular FAK and paxillin.

Conclusions

These results demonstrate that IL-32γ has anti-fibrotic effects and is a novel target for preventing fibrosis.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0863-3) contains supplementary material, which is available to authorized users.

Genetic variant in IL-32 is associated with the ex vivo cytokine production of anti-TNF treated PBMCs from rheumatoid arthritis patients

About 60% of RA patients don't achieve good response with biological disease-modifying anti-rheumatic drugs bDMARD treatment (including TNF inhibitors, TNFi's). Previously, a link between TNFα and interleukin (IL)-32 was reported in RA. However, the exact mechanism linking IL-32 to response to treatment as not been studied yet. Therefore, we explored the influence of a promoter single nucleotide polymorphism (SNP) rs4786370 in IL-32 on clinical responsiveness to TNFi's in RA patients, potentially serving as new biomarker in RA. Expression of pro-inflammatory cytokines by peripheral mononuclear cells (PBMCs) from RA patients and healthy individuals were studied. Moreover, "ex vivo response" and clinical response to anti-TNFα therapy (etanercept, adalimumab) were measured and stratified for the IL-32 SNP. Higher IL-32 protein production was observed in RA patients. Additionally, patients bearing the CC genotype showed higher IL-32 protein and cytokine expression. DAS28 was independent of the promoter SNP, however, the "ex vivo" cytokine response was not. IL-32 mRNA and protein production was higher in RA patients, with a trend towards higher concentrations in patients bearing the CC genotype. Furthermore, genotype dependent IL-1 beta production might predict clinical response to etanercept/adalimumab. This indicates that IL-32 could play a role in predicting response to treatment in RA.

Adipokine dysregulation and adipose tissue inflammation in human obesity

Obesity, a worldwide epidemic, confers increased risk for multiple serious conditions, including type 2 diabetes, cardiovascular diseases, nonalcoholic fatty liver disease and cancer. Adipose tissue is considered one of the largest endocrine organs in the body as well as an active tissue for cellular reactions and metabolic homeostasis rather than an inert tissue for energy storage. The functional pleiotropism of adipose tissue relies on its ability to synthesize and release a large number of hormones, cytokines, extracellular matrix proteins and growth and vasoactive factors, collectively termed adipokines that influence a variety of physiological and pathophysiological processes. In the obese state, excessive visceral fat accumulation causes adipose tissue dysfunctionality that strongly contributes to the onset of obesity-related comorbidities. The mechanisms underlying adipose tissue dysfunction include adipocyte hypertrophy and hyperplasia, increased inflammation, impaired extracellular matrix remodelling and fibrosis together with an altered secretion of adipokines. This review describes how adipose tissue becomes inflamed in obesity and summarizes key players and molecular mechanisms involved in adipose inflammation.

Increased interleukin-32, interleukin-1, and interferon-γ levels in serum from hepatitis B patients and in HBV-stimulated peripheral blood mononuclear cells from healthy volunteers

BACKGROUND

Few studies showed the changes in cytokine profiles after infection by hepatitis B virus (HBV), the most common viral liver disease worldwide. This study examined the relationship between interleukin (IL)-32, IL-1, and interferon (IFN)-γ levels and HBV load.

METHODS

IL-32, IL-1, and IFN-γ levels in hepatitis B patients serum and HBV-stimulated PBMCs were measured by ELISA. Gene transcripts in PBMCs from hepatitis B patients and HBV-stimulated PBMCs from healthy controls were measured by real-time PCR.

RESULTS

IL-32, IL-1, and IFN-γ protein levels in serum from hepatitis B patients were significantly higher than those in healthy volunteers (P<0.05). Hepatitis B patients showed significantly higher expression of IL-32, IL-1, and IFN-γ transcripts than healthy volunteers (P<0.05). IL-32, IL-1, and IFN-γ levels in PBMCs stimulated by different amounts of HBV were significantly higher than those in HBV-unstimulated PBMCs (P<0.05). Real-time PCR results were consistent with the ELISA results.

CONCLUSIONS

The levels of IL-32, IL-1, and IFN-γ protein and transcripts in serum and PBMCs from hepatitis B patients were higher than those in healthy volunteers. Similarly, both were higher in PBMCs from healthy volunteers stimulated by HBV in vitro. However, the changes in cytokine levels were not proportional to the viral load.

Interleukin-32: its role in asthma and potential as a therapeutic agent

Interleukin (IL)-32, also named natural killer cell transcript 4 (NK4), has increasingly been described as an immunoregulator that controls cell differentiation and cell death and is involved in the stimulation of anti−/pro-inflammatory cytokines. Abnormal presence of IL-32 has been repeatedly noticed during the pathogenesis of allergic, infectious, cancerous, and inflammatory diseases. Of particular note was the observation of the anti-inflammatory property of IL-32 in a murine ovalbumin model of allergic asthma. Compared to wild-type mice, IL-32γ transgenic mice show decreased levels of inflammatory cells, recruited eosinophils, and lymphocytes in bronchoalveolar lavage fluid in a mouse model of acute asthma. To date, the molecular mechanism underlying the role of IL-32 in asthma remains to be elucidated. This review aims to summarize recent advances in the pathophysiology of asthma and describe the links to IL-32. The possibilities of using IL-32 as an airway inflammation biomarker and an asthma therapeutic agent are also evaluated.

Role of interleukin-32 in cancer biology

Interleukin-32 (IL-32), a novel proinflammatory cytokine, is highly expressed in various cancer tissues and in established cancer cell lines. IL-32 has been revealed to serve a crucial role in human cancer development, including tumour initiation, proliferation and maintenance. The expression of IL-32 is regulated by numerous factors, including genetic variations, hypoxia and acidosis in the tumour microenvironment. Understanding the underlying mechanisms of IL-32 expression and its function are critical for the discovery of novel therapeutic strategies that target IL-32. This is a review of the current literature on the regulation and function of IL-32 in cancer progression, focusing on the molecular pathways linking IL-32 and tumour development.

Role of IL-32 Gamma on Bone Metabolism in Autoimmune Arthritis

IL-32 acts as a pro-inflammatory cytokine by inducing the synthesis of inflammatory molecules as well as promoting the morphological changes involved in the transformation of monocytes into osteoclasts (OCs). Evaluation of the functions of IL-32 has mainly focused on its inflammatory properties, such as involvement in the pathogenesis of various autoimmune diseases. Recently, IL-32 was shown to be involved in bone metabolism, in which it promotes the differentiation and activation of OCs and plays a key role in bone resorption in inflammatory conditions. IL-32γ also regulates bone formation in conditions such as ankylosing spondylitis and osteoporosis. In this review, we summarize the results of recent studies on the role of IL-32γ in bone metabolism in inflammatory arthritis.

Human Interleukin-32γ Plays a Protective Role in an Experimental Model of Visceral Leishmaniasis in Mice

Visceral leishmaniasis (VL) is a chronic parasitic disease caused by Leishmania infantum in the Americas. During VL, several proinflammatory cytokines are produced in spleen, liver, and bone marrow. However, the role of interleukin-32 (IL-32) has not been explored in this disease. IL-32 can induce production of proinflammatory cytokines in innate immune cells and polarize the adaptive immune response. Herein, we discovered that L. infantum antigens induced expression of mRNA mainly for the IL-32γ isoform but also induced low levels of the IL-32β transcript in human peripheral blood mononuclear cells. Furthermore, infection of human IL-32γ transgenic mice (IL-32γTg mice) with L. infantum promastigote forms increased IL-32γ expression in the spleen and liver. Interestingly, IL-32γTg mice harbored less parasitism in the spleen and liver than wild-type (WT) mice. In addition, IL-32γTg mice showed increased granuloma formation in the liver compared to WT mice. The protection against VL was associated with increased production of nitric oxide (NO), interferon gamma (IFN-γ), IL-17A, and tumor necrosis factor alpha by splenic cells restimulated ex vivo with L. infantum antigens. In parallel, there was an increase in the number of Th1 and Th17 T cells in the spleens of IL-32γTg mice infected with L. infantum IL-32γ induction of IFN-γ and IL-17A expression was found to be essential for NO production by splenic cells of infected animals. These data indicate that IL-32γ potentiates the Th1/Th17 immune response during experimental VL, thus contributing to the control of L. infantum infection.

Interleukin-32: An endogenous danger signal or master regulator of intracellular pathogen infections-Focus on leishmaniases

Interleukin 32 (IL-32) is an intracellular cytokine produced by immune and non immune cells after different stimuli. It contributes to inflammation and control of intracellular pathogens mainly by inducing proinflammatory cytokines and microbicidal molecules. Evidence is rising showing that IL-32 can be considered an endogenous danger signal after tissue injury, amplifying the inflammatory process and acquired immune responses. It seems to be a master regulator of intracellular infectious diseases. In this review, first the general properties of IL-32 are described followed by its role in the immunopathogenesis of inflammatory and infectious diseases. Roles of IL-32 in the control of infectious diseases caused by intracellular pathogens are reported, and later a focus on IL-32 in leishmaniases, diseases caused by an intracellular protozoan, is presented.