IL-32, a novel cytokine with a possible role in disease

Role of interleukin‑32 in cancer progression (Review)

Interleukin (IL)-32 is induced by pro-inflammatory cytokines and promotes the release of inflammatory cytokines. Therefore, it can promote inflammatory responses. The present review article summarized the role of the receptors required for IL-32 action, the biological function of IL-32 and its mechanism of action in tumors. Moreover, it assessed the significance of aberrant IL-32 expression in associated diseases and analyzed the effects of IL-32 on four key types of cancer: Colorectal, gastric, breast and lung. However, the mechanism of action of IL-32 needs to be further demonstrated by assessing the role of this cytokine in cancer to elucidate novel and reliable targets for future cancer treatments.

Role of Fibroblasts in Chronic Inflammatory Signalling in Chronic Rhinosinusitis with Nasal Polyps-A Systematic Review

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an inflammatory disease of the nose and paranasal sinuses characterized by the presence of nasal polyps. The symptoms produced by the presence of nasal polyps such as nasal obstruction, nasal discharge, facial pain, headache, and loss of smell cause a worsening in the quality of life of patients. The source of the nasal polyps remains unclear, although it seems to be due to a chronic inflammation process in the sinonasal mucosa. Fibroblasts, the main cells in connective tissue, are intimately involved in the inflammation processes of various diseases; to this end, we carried out a systematic review to evaluate their inflammatory role in nasal polyps. Thus, we evaluated the main cytokines produced by nasal polyp-derived fibroblasts (NPDF) to assess their involvement in the production of nasal polyps and their involvement in different inflammatory pathways. The results of the review highlight the inflammatory role of NPDF through the secretion of various cytokines involved in the T1, T2, and T3 inflammatory pathways, as well as the ability of NPDF to be stimulated by a multitude of substances. With these findings, the fibroblast is positioned as a new potential therapeutic target in the treatment of CRSwNP.

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.

Multi-omics profiling identifies C1QA/B+ macrophages with multiple immune checkpoints associated with esophageal squamous cell carcinoma (ESCC) liver metastasis

Background

Esophageal squamous cell carcinoma (ESCC) is a highly lethal malignant tumor lacking effective treatments; 20% of ESCC patients develop liver metastasis with an extremely short survival time of ≈5 months. The tumor microenvironment (TME) plays a crucial role in tumor homeostasis, but the relationship between the ESCC TME and liver metastasis is still unknown.

Methods

To identify potential cell populations contributing to ESCC liver metastasis, single-cell RNA (scRNA) sequencing data were analyzed to identify the major cell populations within the TME. Each of the major cell populations was re-clustered to define detailed cell subsets. Thereafter, the gene set variation analysis (GSVA) score was calculated for the bulk RNA-seq data based on the gene signatures of each cell subset. The relationship between the GSVA score of each cellular subset and clinical outcome was further analyzed to identify the cellular subset associated with ESCC liver metastasis, which was validated by multiplex immunohistochemistry.

Results

C1QA/B⁺ tumor-associated macrophages (TAMs) acted as the central regulator of the ESCC TME, closely associated with several key cell subsets. Several immune checkpoints, including CD40, CD47 and LGALS9, were all positively expressed in C1QA/B⁺ macrophages, which may exert central regulatory control of immune evasion by ESCC via these immune checkpoints expressions.

Conclusions

Our results comprehensively revealed the landscape of tumor-infiltrating immune cells associated with ESCC prognosis and metastasis, and suggest a novel strategy for developing immunotherapies for ESCC liver metastasis by targeting C1QA/B⁺ TAMs.

Platelet-Released Growth Factors Influence Wound Healing-Associated Genes in Human Keratinocytes and Ex Vivo Skin Explants

Platelet-released growth factors (PRGFs) or other thrombocyte concentrate products, e.g., Platelet-Rich Fibrin (PRF), have become efficient tools of regenerative medicine in many medical disciplines. In the context of wound healing, it has been demonstrated that treatment of chronic or complicated wounds with PRGF or PRF improves wound healing in the majority of treated patients. Nevertheless, the underlying cellular and molecular mechanism are still poorly understood. Therefore, we aimed to analyze if PRGF-treatment of human keratinocytes caused the induction of genes encoding paracrine factors associated with successful wound healing. The investigated genes were Semaphorin 7A (SEMA7A), Angiopoietin-like 4 (ANGPLT4), Fibroblast Growth Factor-2 (FGF-2), Interleukin-32 (IL-32), the CC-chemokine-ligand 20 (CCL20), the matrix-metalloproteinase-2 (MMP-2), the chemokine C-X-C motif chemokine ligand 10 (CXCL10) and the subunit B of the Platelet-Derived Growth Factor (PDGFB). We observed a significant gene induction of SEMA7A, ANGPLT4, FGF-2, IL-32, MMP-2 and PDGFB in human keratinocytes after PRGF treatment. The CCL20- and CXCL10 gene expressions were significantly inhibited by PRGF therapy. Signal transduction analyses revealed that the PRGF-mediated gene induction of SEMA7A, ANGPLT4, IL-32 and MMP-2 in human keratinocytes was transduced via the IL-6 receptor pathway. In contrast, EGF receptor signaling was not involved in the PRGF-mediated gene expression of analyzed genes in human keratinocytes. Additionally, treatment of ex vivo skin explants with PRGF confirmed a significant gene induction of SEMA7A, ANGPLT4, MMP-2 and PDGFB. Taken together, these results describe a new mechanism that could be responsible for the beneficial wound healing properties of PRGF or related thrombocytes concentrate products such as PRF.

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.

Cytokine Signature and Involvement in Chronic Rhinosinusitis with Nasal Polyps

Cytokines are well known to play a central role in chronic rhinosinusitis with nasal polyps (CRSwNP), particularly in maintenance of the inflammatory response and the recruitment of eosinophils. The pathophysiological concepts concerning the involvement of inflammatory cytokines in CRSwNP have gradually evolved. Although the Th2 cytokines environment associated with an eosinophilic infiltration has retained a central role in the genesis of polyps, the role of other cytokine subpopulations has also and more recently been detailed, leading to a specific and complex signature in CRSwNP. The purpose of this review is to summarize the current state of knowledge about the cytokine signature in CRSwNP, the role of cytokines in the pathogenesis of this disease and in the intercellular dialog between epithelial cells, fibroblasts and inflammatory cells. Knowledge of this precise cytokine signature in CRSwNP is fundamental in the perspective of potential targeting biotherapies.

Prognostic Value of Interleukin-32 Expression and Its Correlation with the Infiltration of Natural Killer Cells in Cutaneous Melanoma

Interleukin-32 (IL-32) is well known as a proinflammatory cytokine that is expressed in various immune cells and cancers. However, the clinical relevance of IL-32 expression in cutaneous melanoma has not been comprehensively studied. Here, we identified the prognostic value of IL32 expression using various systematic multiomic analyses. The IL32 expressions were significantly higher in cutaneous melanoma than in normal tissue, and Kaplan-Meier survival analysis showed a correlation between IL32 expression and good prognosis in cutaneous melanoma patients. In addition, we analyzed the correlation between IL32 expression and the infiltration of natural killer (NK) cells to identify a relevant mechanism between IL32 expression and prognosis in cutaneous melanoma (p = 0.00031). In the relationship between IL32 expression and the infiltration of NK cells, a negative correlation was found in resting NK cells (rho = -0.38, p = 3.95 × 10^-17) whereas a strong positive correlation was observed only in active NK cells (rho = 0.374, p = 1.23 × 10^-16). Moreover, IL32 expression was markedly positively correlated with the cytolytic molecules, such as granzyme and perforin. These data suggest that IL32 expression may increase patient survival through the infiltration and activation of NK cells, representative anticancer effector cells, in cutaneous melanoma. Collectively, this study provides the prognostic value of IL32 expression and its potential role as an effective predictive biomarker for NK cell infiltration in cutaneous melanoma.

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.

Peri-Surgical Inflammatory Profile Associated with Mini-Invasive or Standard Open Lumbar Interbody Fusion Approaches

BACKGROUND

Different surgical approaches are available for lumbar interbody fusion (LIF) to treat disc degeneration. However, a quantification of their invasiveness is lacking, and the definition of minimally invasive surgery (MIS) has not been biochemically detailed. We aimed at characterizing the inflammatory, hematological, and clinical peri-surgical responses to different LIF techniques.

METHODS

68 healthy subjects affected by single-level discopathy (L3 to S1) were addressed to MIS, anterior (ALIF, n = 21) or lateral (LLIF, n = 23), and conventional approaches, transforaminal (TLIF, n = 24), based on the preoperative clinical assessment. Venous blood samples were taken 24 h before the surgery and 24 and 72 h after surgery to assess a wide panel of inflammatory and hematological markers.

RESULTS

martial (serum iron and transferrin) and pro-angiogenic profiles (MMP-2, TWEAK) were improved in ALIF and LLIF compared to TLIF, while the acute phase response (C-reactive protein, sCD163) was enhanced in LLIF.

CONCLUSIONS

MIS procedures (ALIF and LLIF) associated with a reduced incidence of post-operative anemic status, faster recovery, and enhanced pro-angiogenic stimuli compared with TLIF. LLIF associated with an earlier activation of innate immune mechanisms than ALIF and TLIF. The trend of the inflammation markers confirms that the theoretically defined mini-invasive procedures behave as such.

Novel self-amplificatory loop between T cells and tenocytes as a driver of chronicity in tendon disease

OBJECTIVES

Increasing evidence suggests that inflammatory mechanisms play a key role in chronic tendon disease. After observing T cell signatures in human tendinopathy, we explored the interaction between T cells and tendon stromal cells or tenocytes to define their functional contribution to tissue remodelling and inflammation amplification and hence disease perpetuation.

METHODS

T cells were quantified and characterised in healthy and tendinopathic tissues by flow cytometry (FACS), imaging mass cytometry (IMC) and single cell RNA-seq. Tenocyte activation induced by conditioned media from primary damaged tendon or interleukin-1β was evaluated by qPCR. The role of tenocytes in regulating T cell migration was interrogated in a standard transwell membrane system. T cell activation (cell surface markers by FACS and cytokine release by ELISA) and changes in gene expression in tenocytes (qPCR) were assessed in cocultures of T cells and explanted tenocytes.

RESULTS

Significant quantitative differences were observed in healthy compared with tendinopathic tissues. IMC showed T cells in close proximity to tenocytes, suggesting tenocyte-T cell interactions. On activation, tenocytes upregulated inflammatory cytokines, chemokines and adhesion molecules implicated in T cell recruitment and activation. Conditioned media from activated tenocytes induced T cell migration and coculture of tenocytes with T cells resulted in reciprocal activation of T cells. In turn, these activated T cells upregulated production of inflammatory mediators in tenocytes, while increasing the pathogenic collagen 3/collagen 1 ratio.

CONCLUSIONS

Interaction between T cells and tenocytes induces the expression of inflammatory cytokines/chemokines in tenocytes, alters collagen composition favouring collagen 3 and self-amplifies T cell activation via an auto-regulatory feedback loop. Selectively targeting this adaptive/stromal interface may provide novel translational strategies in the management of human tendon disorders.

Correlation between serum IL-32 concentration and clinical parameters of stable COPD: a retrospective clinical analysis

This study was to investigate the association between serum interleukin 32 (IL-32) concentration and clinical parameters in patients with stable chronic obstructive pulmonary disease (COPD). One hundred and sixteen patients with stable COPD and 70 healthy subjects were included in the study. The serum concentration of IL-32 was detected by enzyme-linked immunosorbent assay. The correlation between serum IL-32 and clinical parameters of patients with COPD was analyzed by T-test, one-way analysis of variance, multiple linear regression and receiver operating characteristic curve. The serum concentration of IL-32 in patients with stable COPD was higher than that in healthy control group (p < 0.001) and increased serum IL-32 was positively correlated with GOLD grading (p = 0.026), mMRC score (p = 0.004) and clinical medical history (p = 0.005), but negatively related to FEV1/FVC (p = 0.001) and FEV1% predicted (p = 0.001). Patient's COPD grading (p = 0.001), clinical medical history (p < 0.001) and FEV1/FVC (p = 0.001) exerted a significant impact on serum IL-32. The sensitivity and specificity of serum IL-32 for discerning COPD patients from healthy individuals were 85.34% and 64.29%, and the area under the curve was 0.808 (p < 0.001). Increased IL-32 is involved in the chronic disease progression of COPD, suggesting that IL-32 may be a molecular biomarker that reflects the severity of COPD and contributes to the disease diagnosis.

Interleukin-32 in systemic sclerosis, a potential new biomarker for pulmonary arterial hypertension

Background

Pulmonary arterial hypertension (PAH) is a severe complication of systemic sclerosis (SSc), associated with a progressive elevation in pulmonary vascular resistance and subsequent right heart failure and death. Due to unspecific symptoms, the diagnosis of PAH is often delayed. On this basis, it is of great value to improve current diagnostic methods and develop new strategies for evaluating patients with suspected PAH. Interleukin-32 (IL-32) is a proinflammatory cytokine expressed in damaged vascular cells, and the present study aimed to assess if this cytokine could be a new biomarker of PAH during SSc.

Methods

The IL-32 expression was evaluated in the sera and skin samples of 18 SSc-PAH patients, 21 SSc patients without PAH, 15 patients with idiopathic PAH (iPAH) and 14 healthy controls (HCs), by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC). Receiver-operating characteristic (ROC) curves were performed to evaluate the cut-off of IL-32 in identifying patients with PAH. Furthermore, in SSc patients, correlation analyses were performed between IL-32 sera levels and mean pulmonary artery pressure (mPAP) evaluated by right heart catheterization (RHC) and systolic pulmonary artery pressure (sPAP), obtained by echocardiography. Additionally, the number of skin IL-32+ cells was correlated with modified Rodnan skin score (mRSS).

Results

In SSc-PAH patients, IL-32 sera levels were significantly higher when compared with SSc patients without PAH and patients affected by iPAH. The analysis of ROC curve showed that IL-32 sera levels above 11.12 pg/ml were able to predict patients with PAH (sensitivity = 90%, specificity = 100%). Furthermore, the IL-32 sera levels of patients with SSc correlated with both mPAP and sPAP. In the skin derived from SSc-PAH patients, the number of IL-32+ cells was significantly increased when compared with the skin derived from SSc patients without PAH, correlating with the mRSS.

Conclusion

Our study suggested that sera determination of IL-32 may be a promising approach to evaluate the presence of PAH in SSc patients and together with longitudinal future studies could help to increase the understanding how these biomarkers mirror the vascular changes and the inflammatory process during SSc.

Evidence that TNF-β suppresses osteoblast differentiation of mesenchymal stem cells and resveratrol reverses it through modulation of NF-κB, Sirt1 and Runx2

It has been established that inflammation plays an important role in bone formation and bone loss. Although a lot is known about the role of TNF-α in bone health, very little is understood about TNF-β, also called lymphotoxin. In this report, we examine the effect of TNF-β on osteogenic differentiation of mesenchymal stem cells (MSCs) and its modulation by resveratrol. Monolayer and high-density cultures of MSCs were treated with osteogenic induction medium with/without TNF-β, Sirt1 inhibitor nicotinamide (NAM), antisense oligonucleotides against Sirt1 (ASO) and/or Sirt1 stimulator resveratrol. We found that TNF-β inhibits, in a similar way to NAM or Sirt1-ASO, the early stage of osteogenic differentiation of MSCs and this was accompanied with downregulation of bone-specific matrix, β1-integrin, Runx2 and with upregulation of NF-κB phosphorylation and NF-κB-regulated gene products involved in the inflammatory, degradative processes and apoptosis. However, resveratrol reversed TNF-β- and NAM-suppressed MSCs osteogenesis by activation of Sirt1 and Runx2 that led to osteoblast differentiation. Furthermore, downregulation of Sirt1 by mRNA inhibited the effect of resveratrol, highlighting the important impact of this enzyme in the TNF-β signaling pathway. Finally, resveratrol was able to manifest its effect both by suppression of TNF-β-induced NF-κB and through direct activation of the Sirt1 and Runx2 pathway. Thus, through these studies, we present a mechanism by which a T cell-derived cytokine, TNF-β can affect bone formation through modulation of MSCs differentiation that involves NF-κB, Sirt1, Runx2 and resveratrol reversed TNF-β-promoted impairments in MSCs osteogenesis.

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.

IL-32 and its splice variants are associated with protection against Mycobacterium tuberculosis infection and skewing of Th1/Th17 cytokines

Studies in IL‐32 transgenic mice and in vitro suggest that IL‐32 may have protective effects against Mycobacterium tuberculosis, but so far there are barely any studies in humans. We studied the role of IL‐32 and its splice variants in tuberculosis (TB) in vivo and in vitro. Blood transcriptional analysis showed lower total IL‐32 mRNA levels in pulmonary TB patients compared to patients with latent TB infection and healthy controls. Also, among Indonesian household contacts who were heavily exposed to an infectious TB patient, IL‐32 mRNA levels were higher among those who remained uninfected compared to those who became infected with M. tuberculosis. In peripheral blood mononuclear cells from healthy donors, we found that IL‐32γ, the most potent isoform, was down‐regulated upon M. tuberculosis stimulation. This decrease in IL‐32γ was mirrored by an increase of another splice variant, IL‐32β. Also, a higher IL‐32γ/IL‐32β ratio correlated with IFN‐γ production, whereas a lower ratio correlated with production of IL‐1Ra, IL‐6, and IL‐17. These data suggest that IL‐32 contributes to protection against M. tuberculosis infection, and that this effect may depend on the relative abundance of different IL‐32 isoforms.

The role of pro-inflammatory cytokines in lipid metabolism of metabolic diseases

Adipose tissue has been considered as a crucial source of certain pro-inflammatory cytokines; conversely, these pro-inflammatory cytokines are involved in regulating the proliferation and apoptosis of adipocytes, promoting lipolysis, inhibiting lipid synthesis and decreasing blood lipids, etc. In recent decades, extensive studies have indicated that pro-inflammatory cytokines play important roles in the development of lipid metabolism of metabolic diseases, including obesity, atherosclerosis, steatohepatitis and hyperlipoproteinemia. However, the involved pro-inflammatory cytokines types and the underlying mechanisms remain largely unknown. The "re-discovery" of cancer as a metabolic disorder largely occurred in the last five years. Although pro-inflammatory cytokines have been intensively investigated in cancer research, there are very few studies about the roles of pro-inflammatory cytokines in the lipid metabolism of cancer. In the current review, we provide an overview of the progress that has been made in the roles of different pro-inflammatory cytokines in lipid metabolism of metabolic diseases including cancer.

[Immunology of chronic rhinosinusitis with nasal polyps as a basis for treatment with biologicals]

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial inflammation of the nasal and paranasal mucosa. Until now, no internationally standardized classification could be developed. In most cases, CRS is phenotypically classified according to chronic rhinosinusitis with (CRScNP) and without nasal polyps (CRSsNP). However, recent studies could show that there are numerous endotypes within these phenotypes based on different inflammatory mechanisms. This review describes the important immunological mechanisms of CRScNP and highlights modern treatment options with biologicals directly addressing particular immunological processes.

METHODS

Current knowledge on immunological and molecular processes of CRS, particularly CRScNP, was extracted from Medline, PubMed, national and international study- and guideline-registers, and the Cochrane library by a systematic review of the literature.

RESULTS

Based on current literature, various immunological mechanisms for CRS and CRScNP could be identified. Relevant studies for the treatment of eosinophilic conditions such as asthma or CRScNP are presented and, if available, results of these studies are discussed.

CONCLUSION

The growing insight into the underlying immunological mechanisms of CRScNP could pave the way for new personalized treatment options such as biologicals in the future.

Interleukin-32: Frenemy in cancer?

Interleukin-32 (IL-32) was originally identified in natural killer (NK) cells activated by IL-2 in 1992. Thus, it was named NK cell transcript 4 (NK4) because of its unknown function at that time. The function of IL-32 has been elucidated over the last decade. IL-32 is primarily considered to be a booster of inflammatory reactions because it is induced by pro-inflammatory cytokines and stimulates the production of those cytokines and vice versa. Therefore, many studies have been devoted to studying the roles of IL-32 in inflammation-associated cancers, including gastric, colon cancer, and hepatocellular carcinoma. At the same time, roles of IL-32 have also been discovered in other cancers. Collectively, IL-32 fosters the tumor progression by nuclear factor-κB (NF-κB)-mediated cytokines and metalloproteinase production, as well as stimulation of differentiation into immunosuppressive cell types in some cancer types. However, it is also able to induce tumor cell apoptosis and enhance NK and cytotoxic T cell sensitivity in other cancer types. In this review, we will address the function of each IL-32 isoform in different cancer types studied to date, and suggest further strategies to comprehensively elucidate the roles of IL-32 in a context-dependent manner.

Asian Sand Dust Regulates IL-32 Production in Airway Epithelial Cells: Inhibitory Effect of Glucocorticoids

Purpose

Epidemiologic studies have reported that Asian sand dust (ASD) is associated with chronic inflammatory diseases of the respiratory system. Glucocorticoids (GCs) have potent anti-inflammatory properties. The aims of this study were to evaluate the effects of GCs on ASD-induced interleukin-32 (IL-32) expression and to identify the underlying signaling pathways in airway epithelial cells.

Methods

A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cytotoxicity in A549 and human primary nasal epithelial cells. Expression levels of IL-32 messenger RNA and protein were measured by Western blot, real-time polymerase chain reaction, ELISA, and immunofluorescence staining. Signaling pathways were analyzed using specific inhibitors of Akt, MAPK, or NF- κB. The effects of GCs on the expression of ASD-induced IL-32 were confirmed with ex vivo organ cultures of the nasal interior turbinate.

Results

ASD (0–400 ng/mL) had no significant cytotoxic effects in A549 cells and human primary nasal epithelial cells. Expression levels of IL-32 were dose-dependently upregulated by ASD treatment in A549 cells. ASD induced phosphorylation of Akt, MAPK, and NF-κB, whereas GCs and specific inhibitors of Akt, MAPK, and NF-κB downregulated these activations and the expression of IL-32. These findings were further confirmed in human primary nasal epithelial cells and ex vivo organ cultures of the nasal interior turbinate.

Conclusions

GCs have an inhibitory effect on ASD-induced IL-32 expression via the Akt, MAPK, and NF- κB signaling pathways in airway epithelial cells.

Inhibition of skin carcinogenesis by suppression of NF-κB dependent ITGAV and TIMP-1 expression in IL-32γ overexpressed condition

BACKGROUND

Interleukin-32 (IL-32) has been associated with various diseases. Previous studies have shown that IL-32 inhibited the development of several tumors. However, the role of IL-32γ, an isotype of IL-32, in skin carcinogenesis remains unknown.

METHODS

We compared 7,12-Dimethylbenz[a]anthracene/12-O-Tetradecanoylphorbol-13-acetate (DMBA/TPA)-induced skin carcinogenesis in wild type (WT) and IL-32γ-overexpressing mice to evaluate the role of IL-32γ. We also analyzed cancer stemness and NF-κB signaling in skin cancer cell lines with or without IL-32γ expression by western blotting, quantitative real-time PCR and immunohistochemistry analysis.

RESULTS

Carcinogen-induced tumor incidence in IL-32γ mice was significantly reduced in comparison to that in WT mice. Infiltration of inflammatory cells and the expression levels of pro-inflammatory mediators were decreased in the skin tumor tissues of IL-32γ mice compared with WT mice. Using a genome-wide association study analysis, we found that IL-32 was associated with integrin αV (ITGAV) and tissue inhibitor of metalloproteinase-1 (TIMP-1), which are critical factor for skin carcinogenesis. Reduced expression of ITGAV and TIMP-1 were identified in DMBA/TPA-induced skin tissues of IL-32γ mice compared to that in WT mice. NF-κB activity was also reduced in DMBA/TPA-induced skin tissues of IL-32γ mice. IL-32γ decreased cancer cell sphere formation and expression of stem cell markers, and increased chemotherapy-induced cancer cell death. IL-32γ also downregulated expression of ITGAV and TIMP-1, accompanied with the inhibition of NF-κB activity. In addition, IL-32γ expression with NF-κB inhibitor treatment further reduced skin inflammation, epidermal hyperplasia, and cancer cell sphere formation and downregulated expression levels of ITGAV and TIMP-1.

CONCLUSIONS

These findings indicated that IL-32γ suppressed skin carcinogenesis through the inhibition of both stemness and the inflammatory tumor microenvironment by the downregulation of TIMP-1 and ITGAV via inactivation of NF-κB signaling.

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.

Proteinase 3; a potential target in chronic obstructive pulmonary disease and other chronic inflammatory diseases

Chronic Obstructive Pulmonary Disease (COPD) is a common, multifactorial lung disease which results in significant impairment of patients' health and a large impact on society and health care burden. It is believed to be the result of prolonged, destructive neutrophilic inflammation which results in progressive damage to lung structures. During this process, large quantities of neutrophil serine proteinases (NSPs) are released which initiate the damage and contribute towards driving a persistent inflammatory state.Neutrophil elastase has long been considered the key NSP involved in the pathophysiology of COPD. However, in recent years, a significant role for Proteinase 3 (PR3) in disease development has emerged, both in COPD and other chronic inflammatory conditions. Therefore, there is a need to investigate the importance of PR3 in disease development and hence its potential as a therapeutic target. Research into PR3 has largely been confined to its role as an autoantigen, but PR3 is involved in triggering inflammatory pathways, disrupting cellular signalling, degrading key structural proteins, and pathogen response.This review summarises what is presently known about PR3, explores its involvement particularly in the development of COPD, and indicates areas requiring further investigation.

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 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.

Elevated Gene Expression of Interleukin-32 Isoforms Alpha, Beta, Gamma, and Delta in the Peripheral Blood of Chronic Psoriatic Patients

Inflammatory-mediated reactions have been implicated as contributors in a number of dermatological disorders, including psoriasis. However, the potential of interleukin (IL)-32 and its isoforms to contribute to the pathogenesis of psoriasis remains unexplored. This study was undertaken to investigate the role of IL-32 and its isoforms IL-32α, IL-32β, IL-32γ, and IL-32δ in the peripheral blood of psoriatic patients. The majority of chronic plaque psoriatic patients showed elevated IL-32 mRNA levels in the peripheral blood mononuclear cells (PBMCs) as compared with the levels of IL-32 mRNA in PBMCs of healthy controls (p = 0.001). To further investigate the role of elevated levels of IL-32 in psoriatic patients, IL-32 isoforms mRNAs were determined. All tested isoforms IL-32α, IL-32β, IL-32γ, and IL-32δ were overexpressed in psoriatic patients PBMCs as compared with healthy controls’ PBMCs (p < 0.05). IL-32α mRNA expression was also significantly higher as compared with all other isoforms of IL-32 in PBMCs of psoriatic patients (p < 0.001). In short, this is the first study that shows the role of IL-32 and its isoforms in the peripheral blood of psoriatic patients. Our novel findings support an association between elevated levels of IL-32 and psoriasis. The data also suggest that a major proinflammatory response of IL-32 may derive from IL-32α isoform in psoriasis.

IL-32 gamma reduces lung tumor development through upregulation of TIMP-3 overexpression and hypomethylation

The low expression of tissue inhibitor of metalloproteinase 3 (TIMP-3) is important in inflammatory responses. Therefore, inhibition of TIMP-3 may promote tumor development. Our study showed that expression of TIMP-3 was elevated in lL-32γ mice lung tissues. In this study, we investigated whether IL-32γ mice inhibited lung tumor development through overexpression of TIMP-3 and its methylation. To explore the possible underlying mechanism, lung cancer cells were transfected with IL-32γ cDNA plasmid. A marked increase in TIMP-3 expression was caused by promoter methylation. Mechanistic studies indicated that TIMP-3 overexpression reduced NF-κB activity, which led to cell growth inhibition in IL-32γ transfected lung cancer cells. We also showed that IL-32γ inhibits expression of DNA (cytosine-5-)-methyltransferase 1 (DNMT1). Moreover, IL-32γ inhibits the binding of DNMT1 to TIMP-3 promoter, but this effect was reversed by the treatment of DNA methyltransferase inhibitor (5-Aza-CdR) and NF-κB inhibitor (PS1145), suggesting that a marked increase in TIMP-3 expression was caused by inhibition of promoter hypermethylation via decreased DNMT1 expression through the NF-κB pathway. In an in vivo carcinogen induced lung tumor model, tumor growth was inhibited in IL-32γ overexpressed mice with elevated TIMP-3 expression and hypomethylation accompanied with reduced NF-κB activity. Moreover, in the lung cancer patient tissue, the expression of IL-32 and TIMP-3 was dramatically decreased at a grade-dependent manner compared to normal lung tissue. In summary, IL-32γ may increase TIMP-3 expression via hypomethylation through inactivation of NF-κB activity, and thereby reduce lung tumor growth.

Subtyping of polyposis nasi: phenotypes, endotypes and comorbidities

BACKGROUND

Chronic rhinosinusitis (CRS) is a heterogeneous, multifactorial inflammatory disease of the nasal and paranasal mucosa. It has not been possible to date to develop an internationally standardized, uniform classification for this disorder. A phenotype classification according to CRS with (CRSwNP) and without polyposis (CRSsNP) is usually made. However, a large number of studies have shown that there are also different endotypes of CRS within these phenotypes, with different pathophysiologies of chronic inflammation of the nasal mucosa. This review describes the central immunological processes in nasal polyps, as well as the impact of related diseases on the inflammatory profile of nasal polyps.

MATERIALS AND METHODS

The current knowledge on the immunological and molecular processes of CRS, in particular CRSwNP and its classification into specific endotypes, was put together by means of a structured literature search in Medline, PubMed, the national and international guideline registers, and the Cochrane Library.

RESULTS

Based on the current literature, the different immunological processes in CRS and nasal polyps were elaborated and a graphical representation in the form of an immunological network developed. In addition, different inflammatory profiles can be found in CRSwNP depending on related diseases, such as bronchial asthma, cystic fibrosis (CF), or NASID-Exacerbated Respiratory Disease (N‑ERD).

CONCLUSION

The identification of different endotypes of CRSwNP may help to improve diagnostics and develop novel individual treatment approaches in CRSwNP.

Functional role of human interleukin-32 and nuclear transcription factor-kB in patients with psoriasis and psoriatic arthritis

OBJECTIVE

Inflammation and its associated cell signaling events have been well documented in psoriasis and psoriatic arthritis. However, the potential for interleukin (IL)-32 and its associated signaling to provoke an inflammatory response or to contribute in the pathogenesis of psoriasis or psoriatic arthritis are still in early phase. This study determined the role of IL-32 and nuclear transcription factor (NF)-κB in patients with plaque psoriasis and psoriatic arthritis.

METHODS

Levels of IL-32 were determined in the plasma samples of patients with plaque psoriasis, psoriatic arthritis, and normal healthy subjects by human IL-32-specific Sandwich enzyme-linked immunosorbent assays. To investigate the role of a transcription factor in these patients, activated NF-κBp65 levels were determined in the peripheral blood mononuclear cells (PBMCs) by highly sensitive NF-κB transcription factor kit.

RESULTS

The levels of IL-32 in the plasma samples of plaque psoriasis or psoriatic arthritis patients were found to be significantly higher as compared with the levels of IL-32 present in the normal human plasma samples (P < 0.01). Levels of activated NF-κB were also found higher in plaque psoriasis or psoriatic arthritic patients as compared with the PBMCs of healthy humans (P < 0.05).

CONCLUSIONS

This study shows the role of IL-32 and NF-κB in plaque psoriasis and psoriatic arthritic patients. Results indicate that IL-32 and NF-κB promote inflammation in patients with psoriasis and psoriatic arthritis. Disruption of IL-32 or NF-κB signaling event might provide a novel target for the management of plaque psoriasis and psoriatic arthritis.

Cytokines in the pathogenesis of rheumatoid arthritis: new players and therapeutic targets

In recent years, the landscape of pro- and anti-inflammatory cytokines has rapidly expanded with the identification of new members proven to be involved at different extent in the pathogenesis of chronic immune mediated inflammatory diseases including rheumatoid arthritis (RA). The advance of our understanding of mediators involved in the pathogenesis of RA and in consequence, the development of novel targeted therapies is necessary to provide patients not responding to currently available strategies with novel compounds. The aim of this review article is to provide an overview on recently identified cytokines, emphasizing their pathogenic role and therapeutic potential in RA. A systematic literature review was performed to retrieve articles related to every cytokine discussed in the review. In some cases, evidence from animal models and RA patients is already consistent to move forward into drug development. In others, conflicting observation and the paucity of data require further investigations.Forty years after the discovery of IL-1, the landscape of cytokines is continuously expanding with increasing possibilities to develop novel therapeutic strategies in RA.

IL-32α-induced inflammation constitutes a link between obesity and colon cancer

Growing evidence indicates that adipose tissue inflammation is an important mechanism whereby obesity promotes cancer risk and progression. Since IL-32 is an important inflammatory and remodeling factor in obesity and is also related to colon cancer (CC) development, the aim of this study was to explore whether IL-32 could function as an inflammatory factor in human obesity-associated CC promoting a microenvironment favorable for tumor growth. Samples obtained from 84 subjects [27 lean (LN) and 57 obese (OB)] were used in the study. Enrolled subjects were further subclassified according to the established diagnostic protocol for CC (49 without CC and 35 with CC). We show, for the first time, that obesity (p = 0.009) and CC (p = 0.026) increase circulating concentrations of IL-32α. Consistently, we further showed that gene (p < 0.05) and protein (p < 0.01) expression levels of IL-32α were upregulated in VAT from obese patients with CC. Additionally, we revealed that IL32 expression levels are enhanced by hypoxia and inflammation-related factors in HT-29 CC cells as well as that IL-32α is involved in the upregulation of inflammation (IL8, TNF, and CCL2) and extracellular matrix (ECM) remodeling (SPP1 and MMP9) genes in HT-29 cancer cells. Additionally, we also demonstrate that the adipocyte-conditioned medium obtained from obese patients stimulates (p < 0.05) the expression of IL32 in human CC cells. These findings provide evidence of the potential involvement of IL-32 in the development of obesity-associated CC as a pro-inflammatory and ECM remodeling cytokine.

Aptamers Against Pro- and Anti-Inflammatory Cytokines: A Review

Inflammatory disorders result from continuous inflammation in injured sites. Many molecules are involved in this process; the inhibition of which could prevent the inflammation. Chemokines are a group of these biological mediators which are categorized into pro-, anti-, and pro-/anti-inflammatory. Thus, targeting these essential molecules can be an effective way for prevention and control of inflammatory diseases. Various therapeutic agents have been developed for primary and secondary prevention of these disorders, but each of them has its own limitations. Aptamers, as novel therapeutic agents, are a new generation of drugs which could replace other medications even antibodies. Aptamer can bind to its target molecule to trap it and prohibit its function. Among large group of inflammatory cytokines, only 11 aptamers have been selected either against cytokines or their related receptors. These cytokines include interleukin (IL)-2, IL-6, IL-10, IL-11, IL-17, IL-32, TGF-β, TNF-α, IFN-γ, CCL2, and IP-10. Most of the isolated aptamers are against pro-inflammatory or dual function cytokines, and it seems that they could be used for diagnosis, prevention, and treatment of the related inflammatory diseases. Most of the aptamers have been tested in vitro, but so far, none of them has been approved for in vivo use. Given a vast number of inflammatory cytokines, more aptamers against this group of biological molecules will be selected in the near future. The available aptamers will also be tested in clinical trials. Therefore, a significant improvement is expected for the prevention and control of inflammatory disorders.

Determination of differentially regulated proteins upon proteasome inhibition in AML cell lines by the combination of large-scale and targeted quantitative proteomics

The ubiquitin-proteasome pathway (UPP) plays a critical role in the degradation of proteins implicated in cell cycle control, signal transduction, DNA damage response, apoptosis and immune response. Proteasome inhibitors can inhibit the growth of a broad spectrum of human cancer cells by altering the balance of intracellular proteins. However, the targets of these compounds in acute myeloid leukemia (AML) cells have not been fully characterized. Herein, we combined large-scale quantitative analysis by SILAC-MS and targeted quantitative proteomic analysis in order to identify proteins regulated upon proteasome inhibition in two AML cell lines displaying different stages of maturation: immature KG1a cells and mature U937 cells. In-depth data analysis enabled accurate quantification of more than 7000 proteins in these two cell lines. Several candidates were validated by selected reaction monitoring (SRM) measurements in a large number of samples. Despite the broad range of proteins known to be affected by proteasome inhibition, such as heat shock (HSP) and cell cycle proteins, our analysis identified new differentially regulated proteins, including IL-32, MORF family mortality factors and apoptosis inducing factor SIVA, a target of p53. It could explain why proteasome inhibitors induce stronger apoptotic responses in immature AML cells.

Unveil the mysterious mask of cytokine-based immunotherapy for melanoma

Melanoma is the leading cause of death among all skin cancers and its incidence continues to rise rapidly worldwide in the past decades. The available treatment options for melanoma remain limited despite extensive clinical research. Melanoma is an immunogenic tumor and great advances in immunology in recent decades allow for the development of immunotherapeutic agents against melanoma. In recent years, immunotherapy utilizing cytokines has been particularly successful in certain cancers and holds promise for patients with advanced melanoma. In this review, an overview of the current status and emerging perspectives on cytokine immunotherapy for melanoma are discussed in details. Such a study will be helpful to unveil the mysterious mask of cytokine-based immunotherapy for melanoma.

Interleukin-32 Gamma Stimulates Bone Formation by Increasing miR-29a in Osteoblastic Cells and Prevents the Development of Osteoporosis

Interleukin-32 gamma (IL-32γ) is a recently discovered cytokine that is elevated in inflamed tissues and contributes to pathogenic features of bone in human inflammatory rheumatic diseases. Nevertheless, the role of IL-32γ and its direct involvement in bone metabolism is unclear. We investigated the molecular mechanism of IL-32γ in bone remodeling and the hypothetical correlation between IL-32γ and disease activity in osteoporosis patients. Transgenic (TG) mice overexpressing human IL-32γ showed reduced bone loss with advancing age, increased bone formation, and high osteogenic capacity of osteoblast compared to wild-type (WT) mice through the upregulation of miR-29a, which caused a reduction of Dickkopf-1 (DKK1) expression. IL-32γ TG mice were protected against ovariectomy (OVX)induced osteoporosis compared with WT mice. Decreased plasma IL-32γ levels were associated with bone mineral density (BMD) in human patients linked to increased DKK1 levels. These results indicate that IL-32γ plays a protective role for bone loss, providing clinical evidence of a negative correlation between IL-32γ and DKK1 as bone metabolic markers.

Increased Interleukin-32 Levels in Obesity Promote Adipose Tissue Inflammation and Extracellular Matrix Remodeling: Effect of Weight Loss

Interleukin (IL)-32 is a recently described cytokine involved in the regulation of inflammation. We aimed to explore whether IL-32 could function as an inflammatory and angiogenic factor in human obesity and obesity-associated type 2 diabetes. Samples obtained from 90 subjects were used in the study. Obese patients exhibited higher expression levels of IL-32 in visceral adipose tissue (AT) as well as in subcutaneous AT and peripheral blood mononuclear cells. IL32 was mainly expressed by stromovascular fraction cells, and its expression was significantly enhanced by inflammatory stimuli and hypoxia, whereas no changes were found after the incubation with anti-inflammatory cytokines. The addition of exogenous IL-32 induced the expression of inflammation and extracellular matrix-related genes in human adipocyte cultures, and IL32-silenced adipocytes showed a downregulation of inflammatory genes. Furthermore, adipocyte-conditioned media obtained from obese patients increased IL32 gene expression in human monocyte cultures, whereas the adipocyte-conditioned media from lean volunteers had no effect on IL32 mRNA levels. These findings provide evidence, for the first time, about the inflammatory and remodeling properties of IL-32 in AT, implicating this cytokine in obesity-associated comorbidities.

Decreased severity of collagen antibody and lipopolysaccharide-induced arthritis in human IL-32β overexpressed transgenic mice

Interleukin (IL)-32, mainly produced by T-lymphocytes, natural killer cells, epithelial cells, and blood monocytes, is dominantly known as a pro-inflammatory cytokine. However, the role of IL-32 on inflammatory disease has been doubtful according to diverse conflicting results. This study was designed to examine the role of IL-32β on the development of collagen antibody (CAIA) and lipopolysaccharide (LPS)-induced inflammatory arthritis. Our data showed that the paw swelling volume and clinical score were significantly reduced in the CAIA and LPS-treated IL-32β transgenic mice compared with non-transgenic mice. The populations of cytotoxic T, NK and dendritic cells was inhibited and NF-κB and STAT3 activities were significantly lowered in the CAIA and LPS-treated IL-32β transgenic mice. The expression of pro-inflammatory proteins was prevented in the paw tissues of CAIA and LPS-treated IL-32β transgenic mice. In addition, IL-32β altered several cytokine levels in the blood, spleen and paw joint. Our data indicates that IL-32β comprehensively inhibits the inflammation responses in the CAIA and LPS-induced inflammatory arthritis model.

Toll-like receptor 4-mediated expression of interleukin-32 via the c-Jun N-terminal kinase/protein kinase B/cyclic adenosine monophosphate response element binding protein pathway in chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is prolonged inflammation of the sinonasal mucosa. Interleukin-32 (IL-32) is involved in the pathogenesis of chronic lung inflammatory diseases. The aim of study is to compare the expression level of IL-32 in normal nasal mucosa and CRSwNP and to investigate the mechanism underlying IL-32 expression in CRSwNP.

METHODS

IL-32 expression in nasal tissues, normal nasal mucosa-derived fibroblasts (NorDFs) and nasal polyp-derived fibroblasts (NPDFs), ex vivo explants of nasal tissues was measured by reverse-transcription polymerase chain reaction (RT-PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA). NorDFs and NPDFs were exposed to lipopolysaccharide (LPS) and the expression level of IL-32 was measured. LPS from Rhodobactersphaeroides (RS) and small interference RNA against Toll-like receptor 4 (siTLR4) were used to inhibit signaling by TLR4. Activation of mitogen-activated protein kinase (MAPKs) (extracellular related kinase [ERK], p38, and c-Jun N-terminal kinase [JNK]), protein kinase B (AKT), and cyclic adenosine monophosphate response element binding protein (CREB) was examined using western blot analysis.

RESULTS

Expression of IL-32 was increased in CRSwNP compared to normal nasal mucosa. LPS induced expression of IL-32 in a time-dependent manner. The induction of IL-32 expression in NPDFS was more effective than in NorDFs. Treatment with RS and siTLR4 inhibited the messenger RNA (mRNA) expression of TLR4, myeloid differentiation primary response 88 (MyD88), and IL-32 in LPS-stimulated NPDFs. IL-32 expression was specifically activated by JNK, AKT, and CREB in LPS-stimulated NPDFs and CRSwNP ex vivo explants.

CONCLUSION

The sensitivity for IL-32 expression by LPS was increased in CRSwNP compared to normal nasal mucosa. LPS effectively induced IL-32 expression in NPDFs than in NorDFs through the TLR4-JNK-AKT-CREB signaling pathway. Therefore, IL-32 seems to be involved in the pathogenesis of CRSwNP.

Gene expression changes in subcutaneous adipose tissue due to Cushing's disease

Glucocorticoids have major effects on adipose tissue metabolism. To study tissue mRNA expression changes induced by chronic elevated endogenous glucocorticoids, we performed RNA sequencing on the subcutaneous adipose tissue from patients with Cushing's disease (n=5) compared to patients with nonfunctioning pituitary adenomas (n=11). We found a higher expression of transcripts involved in several metabolic pathways, including lipogenesis, proteolysis and glucose oxidation as well as a decreased expression of transcripts involved in inflammation and protein synthesis. To further study this in a model system, we subjected mice to dexamethasone treatment for 12 weeks and analyzed their inguinal (subcutaneous) fat pads, which led to similar findings. Additionally, mice treated with dexamethasone showed drastic decreases in lean body mass as well as increased fat mass, further supporting the human transcriptomic data. These data provide insight to transcriptional changes that may be responsible for the comorbidities associated with chronic elevations of glucocorticoids.

The Role of Cathelicidin LL-37 in Cancer Development

LL-37 is a C-terminal peptide proteolytically released from 18 kDa human cathelicidin protein (hCAP18). Chronic infections, inflammation, tissue injury and tissue regeneration are all linked with neoplastic growth, and involve LL-37 antibacterial and immunomodulatory functions. Such a link points to the possible involvement of LL-37 peptide in carcinogenesis. An increasing amount of evidence suggests that LL-37 can have two different and contradictory effects--promotion or inhibition of tumor growth. The mechanisms are tissue-specific, complex, and depend mostly on the ability of LL-37 to act as a ligand for different membrane receptors whose expression varies on different cancer cells. Overexpression of LL-37 was found to promote development and progression of ovarian, lung and breast cancers, and to suppress tumorigenesis in colon and gastric cancer. This review explores and summarizes the current views on how LL-37 contributes to immunity, pathophysiology and cell signaling involved in malignant tumor growth.

NKP30-B7-H6 Interaction Aggravates Hepatocyte Damage through Up-Regulation of Interleukin-32 Expression in Hepatitis B Virus-Related Acute-On-Chronic Liver Failure

Background and Aims

Previous work conducted by our group has shown that the accumulation of hepatic natural killer (NK) cells and the up-regulation of natural cytotoxicity receptors (NKP30 and NKP46) on NK cells from patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) were correlated with disease progression in HBV-ACLF. The natural cytotoxicity receptors expressed on NK cells are believed to be probable candidates involved in the NK cell-mediated hepatocyte damage in HBV-ACLF. However, the underlying mechanisms remain to be elucidated. In the present study, we aimed to discover the role of NKP30-B7-H6 interaction in NK cells-mediated hepatocyte damage in HBV-ACLF.

Methods

Hepatic expressions of B7-H6 and interleukin-32 (IL-32) were examined by immunochemistry staining in samples from patients with HBV-ACLF or mild chronic hepatitis B (CHB). The cytotoxicity of NK-92 cell against target cells (Huh-7 and LO2) was evaluated by CCK8 assay. Expression of IL-32 in liver NK cell, T cells and NK-92 cell line was detected by the flow cytometric analysis. The effect of IL-32 on the apoptosis of Huh7 cells was evaluated using Annexin V/PI staining analysis.

Results

An enhancement of hepatic B7-H6 and IL-32 expression was associated with the severity of liver injury in HBV-ACLF. And there was a positive association between hepatic B7-H6 and IL-32 expression. Expressions of IL-32 in liver NK cells and T cells were increased in HBV-ACLF patients. In vitro NK-92 cells are highly capable of killing the high B7-H6 expressing Huh7 cells and B7-H6-tansfected hepatocyte line LO2 cells dependent on NKP30 and B7-H6 interaction. Furthermore, NK-92 cells exhibited elevated IL-32 expression when stimulated with anti-NKP30 antibodies or when co-cultured with Huh7 cells. IL-32 can induce the apoptosis of Huh7 cells in a dose-dependent manner.

Conclusion

Our results suggest that NKP30-B7-H6 interaction can aggravate hepatocyte damage, probably through up-regulation of IL-32 expression in HBV-ACLF.

Maintenance of Epstein-Barr Virus Latent Status by a Novel Mechanism, Latent Membrane Protein 1-Induced Interleukin-32, via the Protein Kinase Cδ Pathway

Epstein-Barr virus (EBV), an oncogenic herpesvirus, has the potential to immortalize primary B cells into lymphoblastoid cell lines (LCLs) in vitro. During immortalization, several EBV products induce cytokines or chemokines, and most of these are required for the proliferation of LCLs. Interleukin-32 (IL-32), a recently discovered proinflammatory cytokine, is upregulated after EBV infection, and this upregulation is detectable in all LCLs tested. EBV latent membrane protein 1 (LMP1) is responsible for inducing IL-32 expression at the mRNA and protein levels. Mechanistically, we showed that this LMP1 induction is provided by the p65 subunit of NF-κB, which binds to and activates the IL-32 promoter. Furthermore, the short hairpin RNA (shRNA)-mediated depletion of endogenous LMP1 and p65 in LCLs suppressed IL-32 expression, further suggesting that LMP1 is the key factor that stimulates IL-32 in LCLs via the NF-κB p65 pathway. Functionally, knockdown of IL-32 in LCLs elicits viral reactivation and affects cytokine expression, but it has no impact on cell proliferation and apoptosis. Of note, we reveal the mechanism whereby IL-32 is involved in the maintenance of EBV viral latency by inactivation of Zta promoter activity. This atypical cytoplasmic IL-32 hijacks the Zta activator protein kinase Cδ (PKCδ) and inhibits its translocation from the cytoplasm to the nucleus, where PKCδ binds to the Zta promoter and activates lytic cycle progression. These novel findings reveal that IL-32 is involved in the maintenance of EBV latency in LCLs. This finding may provide new information to explain how EBV maintains latency, in addition to viral chromatin structure and epigenetic modification.

IMPORTANCE

EBV persists in two states, latency and lytic replication, which is a unique characteristic of human infections. So far, little is known about how herpesviruses maintain latency in particular tissues or cell types. EBV is an excellent model to study this question because more than 90% of people are latently infected. EBV can immortalize primary B cells into lymphoblastoid cell lines in vitro. Expression of IL-32, a novel atypical cytoplasmic proinflammatory cytokine, increased after infection. The expression of IL-32 was controlled by LMP1. In investigating the regulatory mechanism, we demonstrated that the p65 subunit of NF-κB is required for this upregulation. Of note, the important biological activity of IL-32 was to trap protein kinase Cδ in the cytoplasm and prevent it from binding to the Zta promoter, which is the key event for EBV reaction. So, the expression of LMP1-induced IL-32 plays a role in the maintenance of EBV latency.

A panoramic spectrum of complex interplay between the immune system and IL-32 during pathogenesis of various systemic infections and inflammation

Cytokines have always been of great interest due to their vast potential and participation in the progression and pathogenesis of various ailments. Interleukin-32 (IL-32) is a recently identified cytokine, whose gene is located on human chromosome 16 p13.3, with eight exons and six splice variants (IL-32α to IL-32ζ). IL-32α, the most abundant form, is secreted by different types of cells including T cells, natural killer (NK) cells, monocytes, endothelial cells and epithelial cells. It acts as a preferential mediator and effector of abnormal immune responses to multiple inflammatory and auto immune diseases including rheumatoid arthritis, chronic obstructive pulmonary disease (COPD), inflammatory bowel disease (IBD), etc. It was found to stimulate the induction of various chemokines, pro-inflammatory cytokines including IL-1β, IL-6, IL-8, TNF-α and macrophage inflammatory protein-2 (MIP-2). Hence, IL-32 mediates the crucial interplay among immune system and body cells during pathogenesis of various insults. The aim of the present effort is to summarize the role, mechanism of pathogenesis and potential therapeutic applications of IL-32 in different systemic infections and diseased conditions.

Cytokine-modulating strategies and newer cytokine targets for arthritis therapy

Cytokines are the key mediators of inflammation in the course of autoimmune arthritis and other immune-mediated diseases. Uncontrolled production of the pro-inflammatory cytokines such as interferon-γ (IFN-γ), tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and IL-17 can promote autoimmune pathology, whereas anti-inflammatory cytokines including IL-4, IL-10, and IL-27 can help control inflammation and tissue damage. The pro-inflammatory cytokines are the prime targets of the strategies to control rheumatoid arthritis (RA). For example, the neutralization of TNFα, either by engineered anti-cytokine antibodies or by soluble cytokine receptors as decoys, has proven successful in the treatment of RA. The activity of pro-inflammatory cytokines can also be downregulated either by using specific siRNA to inhibit the expression of a particular cytokine or by using small molecule inhibitors of cytokine signaling. Furthermore, the use of anti-inflammatory cytokines or cytokine antagonists delivered via gene therapy has proven to be an effective approach to regulate autoimmunity. Unexpectedly, under certain conditions, TNFα, IFN-γ, and few other cytokines can display anti-inflammatory activities. Increasing awareness of this phenomenon might help develop appropriate regimens to harness or avoid this effect. Furthermore, the relatively newer cytokines such as IL-32, IL-34 and IL-35 are being investigated for their potential role in the pathogenesis and treatment of arthritis.

Evidence that TNF-β (lymphotoxin α) can activate the inflammatory environment in human chondrocytes

Introduction

Inflammatory cytokines play a key role in the pathogenesis of joint diseases such as rheumatoid arthritis (RA). Current therapies target mainly tumor necrosis factor α (TNF-α) as this has proven benefits. However, a large number of patients do not respond to or become resistant to anti-TNF-α therapy. While the role of TNF-α in RA is quite evident, the role of TNF-β, also called lymphotoxin-α (LT-α), is unclear. In this study we investigated whether TNF-β and its receptor play a role in chondrocytes in the inflammatory environment.

Methods

An in vitro model of primary human chondrocytes was used to study TNF-β-mediated inflammatory signaling.

Results

Cytokine-induced inflammation enhances TNF-β and TNF-β-receptor expression in primary human chondrocytes accompanied by the up-regulation of inflammatory (cyclooxygenase-2), matrix degrading (matrix metalloproteinase-9 and -13) and apoptotic (p53, cleaved caspase-3) signaling pathways, all known to be regulated by NF-κB. In contrast, anti-TNF-β, similar to the natural NF-κB inhibitor (curcumin, diferuloylmethane) or the knockdown of NF-κB by using antisense oligonucleotides (ASO), suppressed IL-1β-induced NF-κB activation and its translocation to the nucleus, and abolished the pro-inflammatory and apoptotic effects of IL-1β. This highlights, at least in part, the crucial role of NF-κB in TNF-β-induced-inflammation in cartilage, similar to that expected for TNF-α. Finally, the adhesiveness between TNF-β-expressing T-lymphocytes and the responding chondrocytes was significantly enhanced through a TNF-β-induced inflammatory microenvironment.

Conclusions

These results suggest for the first time that TNF-β is involved in microenvironment inflammation in chondrocytes during RA parallel to TNF-α, resulting in the up-regulation of NF-κB signaling and activation of pro-inflammatory activity.