Marmoset Viral Hepatic Inflammation Induced by Hepatitis C Virus Core Protein via IL-32

IL-32/NFκB/miR-205 loop sustains the high expression of IL-32 and enhances the motility of cervical cancer cells

Human papillomavirus (HPV) infection is a major contributor to cervical cancer. Persistent HPV infection can trigger the expression of IL-32, yet the precise role of IL-32 in the occurrence and development of cervical cancer remains elusive. To investigate this, qRT‒PCR and western blotting were utilized to measure the mRNA and protein expression levels; bioinformatics analysis was used to screen differentially expressed miRNAs; wound healing and transwell assays were conducted to evaluate cell migration and invasion capabilities. Comparative analysis revealed significantly elevated IL-32 expression in cervical cancer tissues and cell lines compared to control groups. In SiHa and/or HeLa, overexpression of IL-32 and IL-32 exposure markedly upregulated miR-205, whereas its knockdown resulted in a substantial downregulation of miR-205. Furthermore, miR-205 also could significantly regulate the expression of IL-32 in HeLa and SiHa cells. Upregulation and downregulation of IL-32 led to a significant increase or decrease in NFκB expression, respectively. Treatment with BAY11-7082 (an NFκB inhibitor) notably decreased miR-205 expression but had no effect on IL-32 levels. qRT‒PCR and western blotting analyses demonstrated that both overexpression and underexpression of IL-32 and miR-205 significantly enhanced or reduced MMP2 and MMP9 expression in cervical cancer cells, respectively. Knockdown of IL-32 significantly inhibited the migration and invasion of HeLa and SiHa; conversely, treatment with rIL-32α and rIL-32γ notably promoted their migration and invasion. In brief, IL-32 is highly expressed via the formation of a positive regulatory loop with NFκB/miR-205, contributing to the persistence of inflammation and promoting the progression of cervical cancer.

Early Phase of Specific Cellular Immune Status Associates with HCV Infection Outcomes in Marmosets

The major mechanism for determination of HCV infection outcomes has not been fully described, particularly in the early phase of the "window-period" of infection. Based on two groups of marmosets infected with HCV-CE1E2p7/GBV-B chimeric virus (HCV chimera) or GBV-B, the immune mechanism correlating with the different outcomes of virus infections was explored in this study. HCV chimera containing the entire HCV core and envelope proteins (CE1E2p7) and GBV-B RNA were intrahepatically injected into four marmosets in each group, respectively. Blood samples were taken from individual animals in an interval of 2 weeks. Viral load and specific T cell responses were detected in two groups of HCV chimera- and GBV-B-infected marmosets. HCV chimera-infected marmosets appeared to have a virally persistent infection over 6 months post inoculation of the virus. Of these, the specific IFN-γ-secretion T cell response slowly developed over 13 to 19 weeks and was maintained at a relatively low level with 40-70 SFC/10⁶ PBMCs, while the specific Treg cell response was rapidly activated over 3 weeks and was maintained at a high level around 5% among lymphocytes. In contrast, GBV-B-infected marmosets presented spontaneous viral clearance within 6 months; the specific IFN-γ-secretion T cell response was quickly established over 5 to 7 weeks and was maintained at a high level with 50-130 SFC/10⁶ PBMCs, while the specific Treg cell response was inactivated and maintained at a baseline below 3% among lymphocytes. In conclusion, the HCV structural proteins inducing immune suppression in the early phase of HCV infection contributed to the viral persistence, of which the activation of Treg cells might play an important role in the inhibition of an effective T cell antiviral response.

Hepatic interleukin 32 attenuates liver injury through repression of necroptosis in cholestasis

OBJECTIVE

We aimed to evaluate the association between interleukin (IL)-32 and necroptosis in cholestatic liver injury.

METHODS

Levels of necroptosis-related markers in cholestatic and control patients, including the receptor-interacting serine-threonine kinase 3 (RIPK3), receptor-interacting serine-threonine kinase 1 (RIPK1), and mixed lineage kinase domain-like (MLKL) were measured. Animal experiments in C57BL/6J and transgenic mice with IL32β/γ overexpression were also conducted to confirm the effect of IL-32 on necroptosis in cholestasis, which was induced by α-naphthylisothiocyanate (ANIT) and 1% lithocholic acid (LCA). PLC/PRF/5-ASBT and primary mouse hepatocytes were utilized for the investigation of the regulation and mechanism of IL-32 in cholestasis.

RESULTS

In the liver tissues of cholestatic patients, the mRNA and protein expressions of RIPK1, RIPK3, and MLKL were increased and associated with IL-32 expression. In addition, expressions of these indicators in the liver of 1% LCA- and ANIT-induced mouse models were significantly increased, while they were markedly decreased in hIL32βLTg and hIL32γLTg mice. After bile acid stimulation, IL-32 and phosphorylated Akt (p-Akt) expressions significantly elevated in a dose-dependent manner. After treated with tumor necrosis factor (TNF)-α, IL-32 inhibited MLKL expression in primary mouse hepatocytes.

CONCLUSION

IL-32 is negatively associated with necroptosis in cholestatic patients. Moreover, IL-32 is induced by p-Akt and effectively attenuates necroptosis in ANIT- or 1% LCA-induced cholestasis.

Monitoring ADO dependent proteolysis in cells using fluorescent reporter proteins

2-Aminoethanethiol dioxygenase (ADO) is the mammalian orthologue of the plant cysteine oxidases and together these enzymes are responsible for catalysing dioxygenation of N-terminal cysteine residues of certain proteins. This modification creates an N-degron motif that permits arginylation and subsequent proteasomal degradation of such proteins via the Arg-branch of the N-degron pathway. In humans 4 proteins have been identified as substrates of ADO; regulators of G-protein signalling (RGS) 4, 5 and 16, and interleukin-32 (IL-32). Nt-cysteine dioxygenation of these proteins occurs rapidly under normoxic conditions, but ADO activity is very sensitive to O2 availability and as such the stability of substrate proteins is inversely proportional to cellular O2 levels. Much is still to understand about the biochemistry and physiology of this pathway in vitro and in vivo, and Cys N-degron targeted fluorescent proteins can provide a simple and effective tool to study this at both subcellular and high-throughput scales. This chapter describes the design, production and implementation of a fluorescent fusion protein proteolytically regulated by ADO and the N-degron pathway.

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.

Interleukin-32 in Pathogenesis of Atopic Diseases: Proinflammatory or Anti-Inflammatory Role?

Atopic diseases, such as atopic dermatitis (AD), allergic asthma (AA), and allergic rhinitis (AR), are increasingly becoming a worldwide issue. This atopic triad originates at an early age and on a multifactorial basis, causing significant discomfort to susceptible individuals. The global case number is now reaching new highs, so exploring immune system regulation and its components is becoming critical. One cytokine, interleukin-32 (IL-32), is involved in inflammation and regulation of the immune system. It has nine isoforms that show varying degrees of expression, both intracellularly and extracellularly. IL-32 is secreted by immune cells, such as monocytes, macrophages, natural killer cells, and T cells, and by nonimmune cells, including fibroblasts, keratinocytes, and endothelial cells. Its production is regulated and augmented by microorganisms, mitogens, and other cytokines. Early studies demonstrated that IL-32 was an immune regulator that functioned to protect against inflammatory diseases, including AD, AA, and AR, and proposed a proinflammatory role for IL-32 in immune regulation and symptom exacerbation. However, several later reports suggested that IL-32 is downregulated in inflammatory diseases and exerts an anti-inflammatory effect. This review article focuses on recent findings regarding the detrimental and protective roles of IL-32 in development and management of inflammatory diseases. The exact role of IL-32 in AD, AA, and AR still remains to be elucidated. Future research should explore new avenues of IL-32 functionality in human inflammatory diseases.

Hepatitis C virus core protein: Not just a nucleocapsid building block, but an immunity and inflammation modulator

Coevolution occurs between viruses and their hosts. The hosts need to evolve means to eliminate pathogenic virus infections, and the viruses, for their own survival and multiplication, have to develop mechanisms to escape clearance by hosts. Hepatitis C virus (HCV) of Flaviviridae is a pathogen which infects human liver and causes hepatitis, a condition of liver inflammation. Unlike most of the other flaviviruses, HCV has an excellent ability to evade host immunity to establish chronic infection. The persistent liver infection leads to chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC), as well as extrahepatic HCV-related diseases. HCV genomic RNA only expresses 10 proteins, many of which bear functions, in addition to those involved in HCV life cycle, for assisting the virus to develop its persistency. HCV core protein is a structural protein which encapsulates HCV genomic RNA and assembles into nucleocapsids. The core protein is also found to exert functions to affect host inflammation and immune responses by altering a variety of host pathways. This paper reviews the studies regarding the HCV core protein-induced alterations of host immunity and inflammatory responses, as well as the involvements of the HCV core protein in pro- and anti-inflammatory cytokine stimulations, host cellular transcription, lipid metabolism, cell apoptosis, cell proliferations, immune cell differentiations, oxidative stress, and hepatocyte steatosis, which leads to liver fibrosis, cirrhosis, and HCC. Implications of roles played by the HCV core protein in therapeutic resistance are also discussed.

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.