Myelin oligodendrocyte glycoprotein (MOG35-55)-induced experimental autoimmune encephalomyelitis is ameliorated in interleukin-32 alpha transgenic mice

Cannabinoid Receptor Type 1 Regulates Drug Reward Behavior via Glutamate Decarboxylase 67 Transcription

Interaction of cannabinoid receptor type 1 (CB1) and GABAergic neuronal activity is involved in drug abuse-related behavior. However, its role in drug-dependent Pavlovian conditioning is not well understood. In this study, we aimed to evaluate the effects of a CB1 agonist, JWH-210, on the development of conditioned place preference (CPP)-induced by methamphetamine (METH). Pretreatment with a synthetic cannabinoid, JWH-210 (CB1 agonist), increased METH-induced CPP score and METH-induced dopamine release in acute striatal slices. Interestingly, CB1 was expressed in glutamate decarboxylase 67 (GAD67) positive cells, and overexpression of CB1 increased GAD67 expression, while CB1 knockdown reduced GAD67 expression in vivo and in vitro. GAD67 is known as an enzyme involved in the synthesis of GABA. CB1 knockdown in the mice striatum increased METH-induced CPP. When GAD67 decreased in the mice striatum, mRNA level of CB1 did not change, suggesting that CB1 can regulate GAD67 expression. GAD67 knockdown in the mouse striatum augmented apomorphine (dopamine receptor D2 agonist)–induced climbing behavior and METH-induced CPP score. Moreover, in the human brain, mRNA level of GAD67 was found to be decreased in drug users. Therefore, we suggest that CB1 potentiates METH-induced CPP through inhibitory GABAergic regulation of dopaminergic neuronal activity.

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.

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.

Paricalcitol improves experimental autoimmune encephalomyelitis (EAE) by suppressing inflammation via NF-κB signaling

Multiple sclerosis (MS) is known as an autoimmune disease in the central nervous system (CNS) characterized by motor deficits, pain, fatigue, cognitive impairment, and sensory and visual dysfunction. MS is considered to be resulted from significant inflammatory response. Paricalcitol (Pari) is a vitamin D2 analogue, which has been indicated to show anti-inflammatory activities in kidney and heart diseases. In the present study, if Pari could ameliorate the experimental autoimmune encephalomyelitis (EAE) was investigated. Here, the C57BL/6 mice were immunized using myelin oligodendrocyte glycoprotein 35-55 (MOG_35-55). Subsequently, Pari was intraperitoneally injected into the mice. As for in vitro analysis, RAW264.7 and Jurkat cells were incubated with Pari together with corresponding stimulus. The results indicated that Pari administration reduced the paralytic severity, neuropathology and apoptosis in MOG-treated mice compared to the MOG single group. Pari also exhibited a significantly inhibitory effect on immune cell infiltration, glial cell activation, expression of pro-inflammatory factors and the activation of nuclear factor κB (NF-κB). The expression of pro-inflammatory regulators and the translocation of NF-κB from cytoplasm into nuclear in RAW264.7 and Jurkat cells under specific stimulation was clearly down-regulated by Pari incubation. Furthermore, we found that suppressing NF-κB with its inhibitor combined with Pari could further reduce the expression of pro-inflammatory factors and associated proteins. These data illustrated that Pari could diminish MOG-triggered EAE, as well as macrophages and T cells activation through blocking NF-κB activation. Collectively, Pari might have therapeutic effects in mouse models with MS.

Staphylococcal enterotoxin B increased severity of experimental model of multiple sclerosis

BACKGROUND

Superantigens can be absorbed trans-mucosal and trans-cutaneous in individuals colonized with superantigen producing Staphylococcus aureus. Ability of superantigens to activate a large numbers of T cells suggests that they may play a role in the course of autoimmune diseases including human multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). In this study we investigated the role of staphylococcal enterotoxin B in immunologic and pathologic changes in experimental animal model of multiple sclerosis.

METHODS

C57BL/6 female mice were treatment with SEB protein prior or post immunization with MOG33-35 peptide. Mice were monitored daily and scored for clinical symptoms following EAE induction. Spleen and spinal cord of mice were removed and used for ELISA and histological studies, respectively.

RESULTS

Treatment with SEB prior induction of EAE, increased clinical score, the concentration of IL-17A, IFN-γ and histological changes compared to control group. Treatment with SEB after induction of EAE caused these changes, but less severe.

DISCUSSION

Since SEB causes demyelination of spinal cord and increases the level of pro-inflammatory cytokine response, infiltration of T-lymphocytes and macrophages to CNS, it may exacerbate the clinical signs of EAE in mice and multiple sclerosis in human.

Impact of interferon β-1b, interferon β-1a and fingolimod therapies on serum interleukins-22, 32α and 34 concentrations in patients with relapsing-remitting multiple sclerosis

Interleukins (ILs)-22, 32α and 34 were monitored in the sera of relapsing-remitting multiple sclerosis (RRMS) patients at different time intervals with or without interferon β-1b, interferon β-1a and fingolimod treatments. The results showed that sera of untreated RRMS patients were statistically higher in concentration of IL-22 (P < .001), but not IL-32α and IL-34, than those of healthy individuals. Interestingly, interferon β-1b, interferon β-1a and fingolimod treatments led to a significant decrease of serum concentrations of ILs-22 and 32α, but not 34, at 6 and 12 months of treatment, compared to their initial concentrations before initiating therapy. The correlation analysis revealed that the changes of serum IL-22 (r = 0.814) and, to a lesser extent, IL-32α (r = 0.381) concentrations were positively correlated with those of expanded disability status score. In conclusion, serum IL-22 concentration may be a potential marker for MS disease severity and efficacy of treatment.

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

Following recent attention focused on IL-32 as an important component involved in the inflammatory cytokine network, we speculated that IL-32's action on IFN-γ and IFN-γ secreting T cell subsets may help sustain the immune activation and dysregulation found in patients with HIV-1 achieving viral suppression. To explore this hypothesis, transcript levels of IL-32 and IFN-γ were evaluated in PBMC from 139 virologically suppressed HIV-1-infected patients and from 63 healthy individuals by Real Time RT-PCR assays. IL-32 and IFN-γ mRNA levels were also analyzed in CD4+ T cells, CD14+ monocytes and lamina propria lymphocytes (LPL) of the gut district in a subgroup of HIV-1-infected subjects. IFN-γ secreting CD4+ (Th1) and CD8+ (Tc1) T cell subset frequencies were evaluated in LPL by multiparametric flow cytometry. Gene expression results revealed that IL-32 and IFN-γ levels in PBMC from HIV-1-positive patients were significantly elevated compared to those from healthy donors, correlated with each other and increased with patient age. Both IL-32 and IFN-γ genes were also more strongly expressed in CD4+ T cells than in CD14+ monocytes. By contrast, IL-32 levels in LPL were comparable to those measured in PBMC, while IFN-γ levels were higher in PBMC than those in LPL. Negative correlations were found between IL-32 levels and the frequencies of Th1 and Tc1 subsets in gut mucosa. Collectively, our results provide the first evidence that IL-32 levels remain elevated in treated HIV-1-infected patients and correlate with IFN-γ, Th1 and Tc1 subsets.

Interleukin-32α Inhibits Endothelial Inflammation, Vascular Smooth Muscle Cell Activation, and Atherosclerosis by Upregulating Timp3 and Reck through suppressing microRNA-205 Biogenesis

Interleukin-32 (IL-32) is a multifaceted cytokine that promotes inflammation and regulates vascular endothelial cell behavior. Although some IL-32 isoforms have been reported to contribute to vascular inflammation and atherosclerosis, the functional role of IL-32α in vascular inflammation and atherogenesis has not been studied.

Methods: IL-32α function was assessed in cells with transient IL-32α overexpression or treated with recombinant human IL-32α by western blotting and mRNA expression analysis. Vascular smooth muscle cell (VSMC) proliferation and migration was examined by BrdU incorporation and wound healing assays, respectively. In addition, the participation of IL-32α on vascular inflammation, arterial wall thickening, and atherosclerosis in vivo was monitored in human IL-32α transgenic (hIL-32α-Tg) mice with or without ApoE knockout (ApoE^-/-/hIL-32α-Tg).

Results: Our analyses showed that IL-32α suppresses genes involved in the inflammatory and immune responses and cell proliferation, and by limiting matrix metalloproteinase (MMP) function. In vivo, administration of hIL-32α inhibited vascular inflammation and atherosclerosis in hIL-32α-Tg and ApoE^-/-/hIL-32α-Tg mice. Subsequent microarray and in silico analysis also revealed a marked decreased in inflammatory gene expression in hIL-32α-Tg mice. Collectively, our studies demonstrated that IL-32α upregulates the atheroprotective genes Timp3 and Reck by downregulating microRNA-205 through regulation of the Rprd2-Dgcr8/Ddx5-Dicer1 biogenesis pathway.

Conclusion: Our findings provide the first direct evidence that IL-32α is an anti-inflammatory and anti-atherogenic cytokine that may be useful as a diagnostic and therapeutic protein in atherosclerosis.

Interleukin 32, inflammation and cancer

Interleukin-32 (IL-32) is a novel cytokine involved in inflammation and cancer development. IL-32 gene consists of eight small exons, and IL-32 mRNA has nine alternative spliced isoforms, and was thought to be secreted because it contains an internal signal sequence and lacks a transmembrane region. IL-32 is initially expressed selectively in activated T cells by mitogen and activated NK cells and their expression is strongly augmented by microbes, mitogens, and other cytokines. The IL-32 is induced mainly by pathogens and pro-inflammatory cytokines, but IL-32 is more prominent in immune cells than in non-immune tissues. The IL-32 transcript is expressed in various human tissues and organs such as the spleen, thymus, leukocyte, lung, small intestine, colon, prostate, heart, placenta, liver, muscle, kidney, pancreas, and brain. Cytokines are critical components of cell signaling pathways that are involved in the regulation of cell growth, metabolism, hormone signaling, immune regulation and a variety of other physiological functions. Earlier studies have demonstrated that IL-32 regulates cell growth, metabolism and immune regulation and is therefore involved in the pathologic regulator or protectant of inflammatory diseases. Previous studies defined that IL-32 is upregulated in the patients with several inflammatory diseases, and is induced by inflammatory responses. However, several reports suggested that IL-32 is downregulated in several inflammatory diseases including asthma, HIV infection disease, neuronal diseases, metabolic disorders, experimental colitis and metabolic disorders. IL-32 is also involved in various cancer malignancies including renal cancer, esophageal cancer and hepatocellular carcinoma, lung cancer, gastric cancer, breast cancer, pancreatic cancer, lymphoma, osteosarcoma, breast cancer, colon cancer and thyroid carcinoma. Other studies suggested that IL-32 decreases tumor development including cervical cancer, colon cancer and prostate cancer, melanoma, pancreatic cancer, liver cancer and chronic myeloid leukemia. Nevertheless, review articles that discuss the roles and its mechanism of IL-32 isoforms focusing on the therapeutic approaches have not yet been reported. In this review article, we will discuss recent findings regarding IL-32 in the development of diseases and further discuss therapeutic approaches targeting IL-32. Moreover, we will suggest that IL-32 could be the target of several diseases and the therapeutic agents for targeting IL-32 may have potential beneficial effects for the treatment of inflammatory diseases and cancers. Future research should open new avenues for the design of novel therapeutic approaches targeting IL-32.

Enhanced dopaminergic neurotoxicity mediated by MPTP in IL-32β transgenic mice

Parkinson's disease (PD) is a neurodegenerative disorder characterized by prominent loss of the nigral dopaminergic neurons and motor symptoms, such as resting tremor and bradykinesia. Evidence suggests that neuroinflammation may play a critical role in PD pathogenesis. Interleukin (IL)-32 is a newly-identified proinflammatory cytokine, which regulates innate and adaptive immune responses by activating p38 MAPK and NF-κB signaling pathways. The cytokine has been implicated in cancers and autoimmune, inflammatory, and infectious diseases. In this study, we attempted to identify the effects of IL-32β on dopaminergic neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), using IL-32β transgenic mice. Male wild type and IL-32β transgenic mice received intraperitoneal injections of vehicle or MPTP (15 mg/kg × 4). Immunohistochemistry showed that overexpression of IL-32β significantly increased MPTP-mediated loss of dopaminergic neurons in the substantia nigra and deletion of tyrosine hydroxylase-positive fibers in the striatum. Dopamine depletion in the striatum and deficit in locomotor activity were enhanced in IL-32β transgenic mice. These results were accompanied by higher neuroinflammatory responses in the brains of transgenic mice. Finally, we found that IL-32β exaggerated MPTP-mediated activation of p38 MAPK and JNK pathways, which have been shown to be involved in MPTP neurotoxicity. These results suggest that IL-32β exacerbates MPTP neurotoxicity through enhanced neuroinflammatory responses.