Prostaglandins in pathogenesis and treatment of multiple sclerosis

Roles of prostaglandins in immunosuppression

Prostaglandins (PGs) play a crucial and multifaceted role in various physiological processes such as intercellular signaling, inflammation regulation, neurotransmission, vasodilation, vasoconstriction, and reproductive functions. The diversity and biological significance of these effects are contingent upon the specific types or subtypes of PGs, with each PG playing a crucial role in distinct physiological and pathological processes. Particularly within the immune system, PGs are essential in modulating the function of immune cells and the magnitude and orientation of immune responses. Hence, a comprehensive comprehension of the functions PG signaling pathways in immunosuppressive regulation holds substantial clinical relevance for disease prevention and treatment strategies. The manuscript provides a review of recent developments in PG signaling in immunosuppressive regulation. Furthermore, the potential clinical applications of PGs in immunosuppression are also discussed. While research into the immunosuppressive effects of PGs required further exploration, targeted therapies against their immunosuppressive pathways might open new avenues for disease prevention and treatment.

Clinical potential of serum prostaglandin A2 as a novel diagnostic biomarker for hepatocellular cancer

BACKGROUND

Hepatocellular cancer (HCC) is one of the most harmful tumors to human health. Currently, there is still a lack of highly sensitive and specific HCC biomarkers in clinical practice. In this study, we aimed to explore the diagnostic performance of prostaglandin A2 (PGA2) for the early detection of HCC.

METHODS

Untargeted metabolomic analyses on normal control (NC) and HCC participants in the discovery cohort were performed, and PGA2 was identified to be dysregulated in HCC. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detecting serum PGA2 was established and applied to validate the dysregulation of PGA2 in another independent validation cohort. Receiver operating characteristic (ROC), decision curve analysis (DCA) and some other statistical analyses were performed to evaluate the diagnostic performance of PGA2 for HCC.

RESULTS

At first, PGA2 was found to be dysregulated in HCC in untargeted metabolomic analyses. Then a precise quantitative LC-MS/MS method for PGA2 has been established and has passed rigorous method validation. Targeted PGA2 analyses confirmed that serum PGA2 was decreased in HCC compared to normal-risk NC and high-risk cirrhosis group. Subsequently, PGA2 was identified as a novel biomarker for the diagnosis of HCC, with an area under the ROC curve (AUC) of 0.911 for differentiating HCC from the combined NC + cirrhosis groups. In addition, PGA2 exhibited high performance for differentiating small-size (AUC = 0.924), early-stage (AUC = 0.917) and AFP (-) HCC (AUC = 0.909) from the control groups. The combination of PGA2 and AFP might be useful in the surveillance of risk population for HCC and early diagnosis of HCC.

CONCLUSION

This study establishes that PGA2 might be a novel diagnostic biomarker for HCC.

Prostaglandins in the Inflamed Central Nervous System: Potential Therapeutic Targets

The global burden of neurological disorders is evident, yet there remains limited efficacious therapeutics for their treatment. There is a growing recognition of the role of inflammation in diseases of the central nervous system (CNS); among the numerous inflammatory mediators involved, prostaglandins play a crucial role. Prostaglandins are small lipid mediators derived from arachidonic acid via multi-enzymatic pathways. The actions of prostaglandins are varied, with each prostaglandin having a specific role in maintaining homeostasis. In the CNS, prostaglandins can have neuroprotective or neurotoxic properties depending on their specific G-protein receptor. These G-protein receptors have varying subfamilies, tissue distribution, and signal transduction cascades. Further studies into the impact of prostaglandins in CNS-based diseases may contribute to the clarification of their actions, hopefully leading to the development of efficacious therapeutic strategies. This review focuses on the roles played by prostaglandins in neural degeneration, with a focus on Alzheimer's Disease, Multiple Sclerosis, and Amyotrophic Lateral Sclerosis in both preclinical and clinical settings. We further discuss current prostaglandin-related agonists and antagonists concerning suggestions for their use as future therapeutics.

Harnessing prostaglandin E2 signaling to ameliorate autoimmunity

The etiology of most autoimmune diseases remains unknown; however, shared among them is a disruption of immunoregulation. Prostaglandin lipid signaling molecules possess context-dependent immunoregulatory properties, making their role in autoimmunity difficult to decipher. For example, prostaglandin E2 (PGE2) can function as an immunosuppressive molecule as well as a proinflammatory mediator in different circumstances, contributing to the expansion and activation of T cell subsets associated with autoimmunity. Recently, PGE2 was shown to play important roles in the resolution and post-resolution phases of inflammation, promoting return to tissue homeostasis. We propose that PGE2 plays both proinflammatory and pro-resolutory roles in the etiology of autoimmunity, and that harnessing this signaling pathway during the resolution phase might help prevent autoimmune attack.

Inhibition of HIF-1α/EP4 axis by hyaluronate-trimethyl chitosan-SPION nanoparticles markedly suppresses the growth and development of cancer cells

Increased expression of Hypoxia-inducible factor-1α (HIF-1α) in the tumor microenvironment, mainly due to tumor growth, plays a major role in the growth of cancer. Tumor cells induce the expression of cyclooxygenase 2 (COX2) and its product, prostaglandin E2 (PGE2), through overexpression of HIF-1α. It has been shown that ligation of PGE2 with its receptor, EP4, robustly promotes cancer progression. HIF-1α/COX2/PGE2/EP4 signaling pathways appear to play an important role in tumor growth. Therefore, we decided to block the expansion of cancer cells by blocking the initiator (HIF-1α) and end (EP4) of this pathway. In this study, we used hyaluronate (HA), and trimethyl chitosan (TMC) recoated superparamagnetic iron oxide nanoparticles (SPIONs) loaded with HIF-1α-silencing siRNA and the EP4 antagonist (E7046) to treat cancer cells and assessed the effect of combination therapy on cancer progression. The results showed that optimum physicochemical characteristics of NPs (size 126.9 nm, zeta potential 27 mV, PDI < 0.2) and linkage of HA with CD44 molecules overexpressed on cancer cells could deliver siRNAs to cancer cells and significantly suppress the HIF-1α in them. Combination therapy of cancer cells by using HIF-1α siRNA-loaded SPION-TMC-HA NPs and E7046 also prevent proliferation, migration, invasion, angiogenesis, and colony formation of the cancer cells, remarkably.

A Systematic Review on the Role of Arachidonic Acid Pathway in Multiple Sclerosis

BACKGROUND & OBJECTIVE

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease characterized by destruction of oligodendrocytes, immune cell infiltration and demyelination. Inflammation plays a significant role in MS, and the inflammatory mediators such as eicosanoids, leukotrienes, superoxide radicals are involved in pro-inflammatory responses in MS. In this systematic review we tried to define and discuss all the findings of in vivo animal studies and human clinical trials on the potential association between arachidonic acid (AA) pathway and multiple sclerosis.

METHODS

A systematic literature search across Pubmed, Scopus, Embase and Cochrane database was conducted. This systematic review was performed according to PRISMA guidelines.

RESULTS

A total of 146 studies were included, of which 34 were conducted in animals, 58 in humans, and 60 studies reported the role of different compounds that target AA mediators or their corresponding enzymes/ receptors, and can have a therapeutic effect in MS. These results suggest that eicosanoids have significant roles in experimental autoimmune encephalomyelitis (EAE) and MS. The data from animal and human studies elucidated that PGI2, PGF2α, PGD2, isoprostanes, PGE2, PLA2, LTs are increased in MS. PLA2 inhibition modulates the progression of the disease. PGE1 analogues can be a useful option in the treatment of MS.

CONCLUSIONS

All studies reported the beneficial effects of COX and LOX inhibitors in MS. The hybrid compounds, such as COX-2 inhibitors/TP antagonists and 5-LOX inhibitors can be an innovative approach for multiple sclerosis treatment. Future work in MS should shed light in synthesizing new compounds targeting arachidonic acid pathway.

Effects of Cajanus cajan (L.) millsp. roots extracts on the antioxidant and anti-inflammatory activities

Cajanus cajan (L.) Millsp., also named pigeon pea, is widely grown in the tropics and the subtropics. C. cajan roots (CR) and ribs stewed in hot water have been used as a traditional medicine in various cultures to treat diabetes. The purpose of this study was to determine the functional components of hot water (WCR) and 50%, 95% ethanol extracts (EECR50 and EECR95) from CR, then evaluating their antioxidant and anti-inflammatory effects. The results indicated that EECR95 had higher polyphenol, especially the isoflavones (e.x. daidzein, genistein, and cajanol) than those of the other extracts, and it also exhibited the most potent anti-oxidative activities by in vitro antioxidant assay. In the lipopolysaccharide-stimulated RAW 264.7 cells, we found that EECR95 significantly decreased intracellular reactive oxygen species and significantly enhanced the activities of superoxide dismutase and catalase. Mechanism studies showed that EECR95 mainly activated nuclear factor (NF) erythroid 2-related factor 2/antioxidant protein heme oxygenase-1 and inhibited nuclear factor kappa B (NF-κB) signaling pathway, and thus exhibited antioxidant and anti-inflammatory effects. Overall, this study suggests that CR may have the potential to be developed as a biomedical material and that genistein, which has relatively high uptakes (3.44% for the pure compound and 1.73% for endogenous genistein of EECR95) at 24 h of incubation with RAW 264.7 cells, could be the main active component of CR.

Serum pro-inflammatory and anti-inflammatory cytokines and the pathogenesis of experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) as an experimental model of multiple sclerosis (MS) is characterized by demyelination, infiltration of inflammatory cells into the nervous system and dysregulation of serum inflammatory cytokines. We investigated the correlation of serum cytokines and other inflammatory markers with the EAE pathogenesis. After EAE induction, the levels of different serum cytokine/inflammatory mediators were measured. Furthermore, motor functions, myelination, and lymphocyte infiltration in EAE mice were also assessed. Our results revealed that the serum concentrations of T-helper 1 (Th1) and Th17 cytokines, interleukin (IL)-6, IL-1β, IL-1α and prostaglandin E2 in EAE mice were significantly higher than controls. The ratios of pro- to anti-inflammatory cytokines were different between the EAE and the control group. A statistically significant positive correlation was found between the IL-6/IL-10 ratio and the EAE severity, demyelination rate, and lymphocyte infiltration in EAE mice. Results indicate that the profiles of serum pro- and anti-inflammatory cytokines might be useful as biomarkers for monitoring the pathological manifestation of EAE. Furthermore, evaluating the dynamic interplay of serum cytokine levels and the correlation with pathogenic mechanisms of EAE may provide diagnostic and therapeutic insights for MS and some other inflammatory disorders.

Gut Inflammation in Association With Pathogenesis of Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative disease that is generally thought to be caused by multiple factors, including environmental and genetic factors. Emerging evidence suggests that intestinal disturbances, such as constipation, are common non-motor symptoms of PD. Gut inflammation may be closely associated with pathogenesis in PD. This review aims to discuss the cross-talk between gut inflammation and PD pathology initiation and progression. Firstly, we will highlight the studies demonstrating how gut inflammation is related to PD. Secondly, we will analyze how gut inflammation spreads from the gastro-intestine to the brain. Here, we will mainly discuss the neural pathway of pathologic α-syn and the systemic inflammatory routes. Thereafter, we will address how alterations in the brain subsequently lead to dopaminergic neuron degeneration, in which oxidative stress, glutamate excitotoxicity, T cell driven inflammation and cyclooxygenase-2 (COX-2) are involved. We conclude a model of PD triggered by gut inflammation, which provides a new angle to understand the mechanisms of the disease.

Prostaglandin E2 as a potent therapeutic target for treatment of colon cancer

Although colon cancer is one of the most important triggers of cancer related mortality, a few therapeutic options exist for this disease, including combination chemotherapy, anti-EGFR and anti-angiogenic agents. However, none of these therapeutics are fully effective for complete remission, and this issue needs further investigations, particularly in the patients with advanced disease. It has been shown that colon carcinogenesis process is associated with upregulation of prostaglandin (PG) levels. Moreover, conversion of pre-malignant cells to malignant was also related with increased generation of PGs in susceptible subjects. Among the prostanoids, PGE2 is the most important produced member which generated in high levels by colon tumor cells. Generation of PGE2 by action of cyclooxygenase (COX)-2 can promote growth and development, resistance to apoptosis, proliferation, invasion and metastasis, angiogenesis and drug resistance in colon cancer. Increased levels of PGE2 and COX-2 in colon cancer is reported by various investigators which was associated with disease progression. It is suggested that there is a positive feedback loop between COX-2 and PGE2, in which function of COX-2 induces generation of PGE2, and upregulation of PGE2 increases the expression of COX-2 in colon cancer. Although an existence of this feedback loop is well-documented, its precise mechanism, signaling pathways, and the particular E-type prostanoid (EP) receptor mediating this feedback are elusive. Therefore, it seems that targeting COX-2/PGE2/EP receptors may be supposed as a potent therapeutic strategy for treatment of colon cancer. In this review, we try to clarify the role of PGE2 in cancer progression and its targeting for treatment of colon cancer.

Murrayanine Attenuates Lipopolysaccharide-induced Inflammation and Protects Mice from Sepsis-associated Organ Failure

Murrayanine (MK) is the main compound isolated from Murraya koenigii, an aromatic plant belonging to the Rutaceae family, also known as curry leaf tree. Murrayanine was reported to possess potential antioxidant, antimycobacterial and antifungal effects. However, its effect in sepsis remains unclear. This study was designed to investigate the anti-inflammatory effect of MK using both in vitro and in vivo assay. Results of this study indicated that MK decreased NO, TNF-α and IL-6 production in both lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and murine peritoneal macrophages. Moreover, iNOS and COX-2 protein expression as well as their downstream product, PGE2, was also decreased effectively in RAW 264.7 cells. Furthermore, MK decreased the phosphorylation of IKB and repressed NF-kB activity in LPS-activated RAW 264.7 cells. Additionally, we evaluated MK efficacy in vivo using LPS-induced sepsis, a systemic inflammation model in mice. Administration of MK inhibits pro-inflammatory cytokines (TNF-α and IL-6) secretion; decreases AST, ALT, BUN and CRE level in mouse sera; mitigates lung, liver and kidney injuries; and also increases LPS-challenged mice survival rate. Collectively, our results suggest that MK exerts potential as a new anti-inflammatory and immunosuppressive drug in sepsis treatment.

Therapeutic potentials of ginger for treatment of Multiple sclerosis: A review with emphasis on its immunomodulatory, anti-inflammatory and anti-oxidative properties

Multiple sclerosis (MS) is characterized by chronic inflammatory response-induced demyelination of the neurons and degeneration of the axons within the central nervous system (CNS). A complex network of immunopathological-, inflammatory- and oxidative parameters involve in the development and advancement of MS. The anti-inflammatory, immunomodulatory and anti-oxidative characteristics of the ginger and several of its components have been indicated in some of experimental and clinical investigations. The possible therapeutic potentials of ginger and its ingredients in the treatment of MS may exert mainly through the regulation of the Th1-, Th2-, Th9-, Th17-, Th22- and Treg cell-related immune responses, down-regulation of the B cell-related immune responses, modulation of the macrophages-related responses, modulation of the production of pro- and anti-inflammatory cytokines, down-regulation of the arachidonic acid-derived mediators, interfering with the toll like receptor-related signaling pathways, suppression of the inflammasomes, down-regulation of the oxidative stress, reduction of the adhesion molecules expression, and down-regulation of the expression of the chemokines and chemokine receptors. This review aimed to provide a comprehensive knowledge regarding the immunomodulatory-, anti-inflammatory and anti-oxidative properties of ginger and its components, and highlight novel insights into the possible therapeutic potentials of this plant for treatment of MS. The review encourages more investigations to consider the therapeutic potentials of ginger and its effective components for managing of MS.

Multiple Sclerosis: Immunopathology and Treatment Update

The treatment of multiple sclerosis (MS) has changed over the last 20 years. All immunotherapeutic drugs target relapsing remitting MS (RRMS) and it still remains a medical challenge in MS to develop a treatment for progressive forms. The most common injectable disease-modifying therapies in RRMS include β-interferons 1a or 1b and glatiramer acetate. However, one of the major challenges of injectable disease-modifying therapies has been poor treatment adherence with approximately 50% of patients discontinuing the therapy within the first year. Herein, we go back to the basics to understand the immunopathophysiology of MS to gain insights in the development of new improved drug treatments. We present current disease-modifying therapies (interferons, glatiramer acetate, dimethyl fumarate, teriflunomide, fingolimod, mitoxantrone), humanized monoclonal antibodies (natalizumab, ofatumumb, ocrelizumab, alentuzumab, daclizumab) and emerging immune modulating approaches (stem cells, DNA vaccines, nanoparticles, altered peptide ligands) for the treatment of MS.

Multiple sclerosis: Therapeutic applications of advancing drug delivery systems

Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system, which is accompanying with demyelination, neurodegeneration and sensibility to oxidative stress. In MS, auto-reactive lymphocytes cross the blood-brain barrier (BBB) and reside in the perivenous demyelinating lesions which create various distinct inflammatory demyelinated plaques situated predominantly in the white matter. The current MS-related therapeutic approaches can be classified into disease-modifying therapies (DMTs) and symptomatic therapy. DMTs suppress circulating immune cells, inhibit passing the BBB and decrease the inflammatory responses. Recent advances have remarkably delayed disease development and improved the quality of life for numerous patients. In spite of major improvements in therapeutic options, there are some limitations regarding the routes of administration and the necessity for repeated and long-term dosing in which cause to systemic disadvantageous consequences and patient non-compliance. Nanotechnology presents promising approaches to improve autoimmune disease treatment with the capability to overcome many of the limitations common to the current immunosuppressive and biological therapies. Here we emphasis on nanomedicine-based drug delivery approaches of biological immunomodulatory mediators for the treatment of multiple sclerosis. This comprehensive review details the most successful drugs in MS therapy and also focuses on conceptions and clinical potential of novel nanomedicine attitudes for inducing immunosuppression and immunological tolerance in MS to modulate abnormal and pathologic immune responses.

Hydrogen-rich water improves neurological functional recovery in experimental autoimmune encephalomyelitis mice

Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS). The high costs, inconvenient administration, and side effects of current Food and Drug Administration (FDA)-approved drugs often lead to poor adherence to the long-term treatment of MS. Molecular hydrogen (H2) has been reported to exhibit anti-oxidant, anti-apoptotic, anti-inflammatory, anti-allergy, and anti-cancer effects. In the present study, we explored the prophylactic and therapeutic effects of hydrogen-rich water (HRW) on the progress of experimental autoimmune encephalomyelitis (EAE), the animal model for MS. We found that prophylactic administration of both 0.36mM and 0.89mM HRW was able to delay EAE onset and reduce maximum clinical scores. Moreover, 0.89mM HRW also reduced disease severity, CNS infiltration, and demyelination when administered after the onset of disease. Furthermore, HRW treatment prevented infiltration of CD4(+) T lymphocytes into the CNS and inhibited Th17 cell development without affecting Th1 cell populations. Because HRW is non-toxic, inexpensive, easily administered, and can readily cross the blood-brain barrier, our experiments suggest that HRW may have great potential in the treatment of MS.

The role of adenosine and adenosine receptors in the immunopathogenesis of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a heterogeneous neurological disorder with multifactorial etiologies characterized by demyelination, axonal degeneration, and oligodendroglial death. It is believed that both genetics and environmental risk factors such as infection are involved in disease etiology. Accumulating evidence indicates that alteration in purinergic system signaling is involved in immunity and inflammation. Adenosine, a key purine nucleoside, has been shown to be produced during metabolic stress, including ischemia, inflammatory condition, and tissue injury.

METHODS

Extracellular adenosine directly affects various physiological and pathological processes of MS by stimulating G protein-coupled adenosine receptors A1, A2A, A2B, and A3 on the surface of immune cells. It has been suggested that promotion of adenosinergic system may be an important factor in MS pathophysiology and considered as promising therapeutic target for this disease.

CONCLUSION

In this review, we will discuss about the immunopathologic effects of adenosine on MS and its animal model, experimental autoimmune encephalomyelitis.

Anti-inflammatory effects and antioxidant activity of dihydroasparagusic acid in lipopolysaccharide-activated microglial cells

The activation of microglia and subsequent release of toxic pro-inflammatory factors are crucially associated with neurodegenerative disease, characterized by increased oxidative stress and neuroinflammation, including Alzheimer and Parkinson diseases and multiple sclerosis. Dihydroasparagusic acid is the reduced form of asparagusic acid, a sulfur-containing flavor component produced by Asparagus plants. It has two thiolic functions able to coordinate the metal ions, and a carboxylic moiety, a polar function, which may enhance excretion of the complexes. Thiol functions are also present in several biomolecules with important physiological antioxidant role as glutathione. The aim of this study is to evaluate the anti-inflammatory and antioxidant potential effect of dihydroasparagusic acid on microglial activation in an in vitro model of neuroinflammation. We have used lipopolysaccharide to induce an inflammatory response in primary rat microglial cultures. Our results suggest that dihydroasparagusic acid significantly prevented lipopolysaccharide-induced production of pro-inflammatory and neurotoxic mediators such as nitric oxide, tumor necrosis factor-α, prostaglandin E2, as well as inducible nitric oxide synthase and cyclooxygenase-2 protein expression and lipoxygenase activity in microglia cells. Moreover it effectively suppressed the level of reactive oxygen species and affected lipopolysaccharide-stimulated activation of mitogen activated protein kinase, including p38, and nuclear factor-kB pathway. These results suggest that dihydroasparagusic acid's neuroprotective properties may be due to its ability to dampen induction of microglial activation. It is a compound that can effectively inhibit inflammatory and oxidative processes that are important factors of the etiopathogenesis of neurodegenerative diseases.

IL-21 and IL-21 receptor in the immunopathogenesis of multiple sclerosis

Cytokines are considered important factors in the modulation of various immune responses. Among them, interleukin (IL)-21 is one of the major immune modulators, adjusting various immune responses by affecting various immune cells. It has been suggested that IL-21 may enhance autoimmunity through different mechanisms, such as development and activation of helper T (TH)-17 and follicular helper T (TFH) cells, activation of natural killer (NK) cells, enhancing B-cell differentiation and antibody secretion and suppression of regulatory T (Treg) cells. Moreover, IL-21 has also been suggested to be an inducer of autoimmunity when following treatment of MS patients with some therapeutics such as alemtuzumab. This review will seek to clarify the precise role of IL-21/IL-21R in the pathogenesis of MS and, in its animal model, experimental autoimmune encephalomyelitis (EAE).

Calcium-independent phospholipases A2 and their roles in biological processes and diseases

Among the family of phospholipases A2 (PLA2s) are the Ca(2+)-independent PLA2s (iPLA2s) and they are designated group VI iPLA2s. In relation to secretory and cytosolic PLA2s, the iPLA2s are more recently described and details of their expression and roles in biological functions are rapidly emerging. The iPLA2s or patatin-like phospholipases (PNPLAs) are intracellular enzymes that do not require Ca(2+) for activity, and contain lipase (GXSXG) and nucleotide-binding (GXGXXG) consensus sequences. Though nine PNPLAs have been recognized, PNPLA8 (membrane-associated iPLA2γ) and PNPLA9 (cytosol-associated iPLA2β) are the most widely studied and understood. The iPLA2s manifest a variety of activities in addition to phospholipase, are ubiquitously expressed, and participate in a multitude of biological processes, including fat catabolism, cell differentiation, maintenance of mitochondrial integrity, phospholipid remodeling, cell proliferation, signal transduction, and cell death. As might be expected, increased or decreased expression of iPLA2s can have profound effects on the metabolic state, CNS function, cardiovascular performance, and cell survival; therefore, dysregulation of iPLA2s can be a critical factor in the development of many diseases. This review is aimed at providing a general framework of the current understanding of the iPLA2s and discussion of the potential mechanisms of action of the iPLA2s and related involved lipid mediators.

Acute arsenic treatment alters arachidonic acid and its associated metabolite levels in the brain of C57Bl/6 mice

The toxic effects of arsenic on the whole brain, as well as the discrete regions, has been previously reported for mice. We investigated the effects of acute arsenite (As(III)) on brain levels of arachidonic acid (AA) and its associated metabolites generated through cytochrome P450 (CYP), cyclooxygenase (COX), and lipoxygenase (LOX) pathways. Our results demonstrated that acute As(III) treatment (12.5 mg·(kg body mass)−1) decreases cytosolic phospholipase A2 (cPLA2) with a subsequent decrease in its catalytic activity and brain AA levels. In addition, As(III) differentially altered CYP epoxygenases and CYP ω-hydroxylases, but it did not affect brain Ephx2 mRNA or sEH catalytic activity levels. As(III)-mediated effects on Cyps caused an increase in brain 5,6-epoxyeicosatrienoic acid (5,6-EET) and 16/17-hydroxyeicosatetreinoic acid (16/17-HETE) levels, and a decrease in 18- and 20-HETE levels. Furthermore, As(III) increased cyclooxygenase-2 (COX-2) mRNA while decreasing prostaglandins F2α (PGF2α) and PGJ2. As(III) also increased brain 5-lipoxygenase (5-LOX) and 15-LOX mRNA, but decreased 12-LOX mRNA. These changes in LOX mRNA were associated with a decrease in 8/12-HETE levels only. In conclusion, this is the first demonstration that As(III) decreases AA levels coinciding with alterations to EET, HETE, and PG levels, which affects brain development and neurochemistry.

Anti-inflammatory mechanism of α-viniferin regulates lipopolysaccharide-induced release of proinflammatory mediators in BV2 microglial cells

α-Viniferin is an oligostilbene of trimeric resveratrol and has anticancer activity; however, the molecular mechanism underlying the anti-inflammatory effects of α-viniferin has not been completely elucidated thus far. Therefore, we determined the mechanism by which α-viniferin regulates lipopolysaccharide (LPS)-induced expression of proinflammatory mediators in BV2 microglial cells. Treatment with α-viniferin isolated from Clematis mandshurica decreased LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2). α-Viniferin also downregulated the LPS-induced expression of proinflammatory genes such as iNOS and COX-2 by suppressing the activity of nuclear factor kappa B (NF-κB) via dephosphorylation of Akt/PI3K. Treatment with a specific NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), indirectly showed that NF-κB is a crucial transcription factor for expression of these genes in the early stage of inflammation. Additionally, our results indicated that α-viniferin suppresses NO and PGE2 production in the late stage of inflammation through induction of heme oxygenase-1 (HO-1) regulated by nuclear factor erythroid 2-related factor (Nrf2). Taken together, our data indicate that α-viniferin suppresses the expression of proinflammatory genes iNOS and COX-2 in the early stage of inflammation by inhibiting the Akt/PI3K-dependent NF-κB activation and inhibits the production of proinflammatory mediators NO and PGE2 in the late stage by stimulating Nrf2-mediated HO-1 signaling pathway in LPS-stimulated BV2 microglial cells. These results suggest that α-viniferin may be a potential candidate to regulate LPS-induced inflammation.

Analysis of the host transcriptome from demyelinating spinal cord of murine coronavirus-infected mice

Persistent infection of the mouse central nervous system (CNS) with mouse hepatitis virus (MHV) induces a demyelinating disease pathologically similar to multiple sclerosis and is therefore used as a model system. There is little information regarding the host factors that correlate with and contribute to MHV-induced demyelination. Here, we detail the genes and pathways associated with MHV-induced demyelinating disease in the spinal cord. High-throughput sequencing of the host transcriptome revealed that demyelination is accompanied by numerous transcriptional changes indicative of immune infiltration as well as changes in the cytokine milieu and lipid metabolism. We found evidence that a Th1-biased cytokine/chemokine response and eicosanoid-derived inflammation accompany persistent MHV infection and that antigen presentation is ongoing. Interestingly, increased expression of genes involved in lipid transport, processing, and catabolism, including some with known roles in neurodegenerative diseases, coincided with demyelination. Lastly, expression of several genes involved in osteoclast or bone-resident macrophage function, most notably TREM2 and DAP12, was upregulated in persistently infected mouse spinal cord. This study highlights the complexity of the host antiviral response, which accompany MHV-induced demyelination, and further supports previous findings that MHV-induced demyelination is immune-mediated. Interestingly, these data suggest a parallel between bone reabsorption by osteoclasts and myelin debris clearance by microglia in the bone and the CNS, respectively. To our knowledge, this is the first report of using an RNA-seq approach to study the host CNS response to persistent viral infection.

Prostacyclin promotes oligodendrocyte precursor recruitment and remyelination after spinal cord demyelination

Adult oligodendrocyte precursor cells (OPCs) are located adjacent to demyelinated lesion and contribute to myelin repair. The crucial step in remyelination is the migration of OPCs to the demyelinated area; however, the mechanism of OPC migration remains to be fully elucidated. Here we show that prostacyclin (prostaglandin I2, PGI2) promotes OPC migration, thereby promoting remyelination and functional recovery in mice after demyelination induced by injecting lysophosphatidylcholine (LPC) into the spinal cord. Prostacyclin analogs enhanced OPC migration via a protein kinase A (PKA)-dependent mechanism, and prostacyclin synthase expression was increased in the spinal cord after LPC injection. Notably, pharmacological inhibition of prostacyclin receptor (IP receptor) impaired remyelination and motor recovery, whereas the administration of a prostacyclin analog promoted remyelination and motor recovery after LPC injection. Our results suggest that prostacyclin could be a key molecule for facilitating the migration of OPCs that are essential for repairing demyelinated areas, and it may be useful in treating disorders characterized by demyelination.

Ethanol extract of Cnidium officinale exhibits anti-inflammatory effects in BV2 microglial cells by suppressing NF-κB nuclear translocation and the activation of the PI3K/Akt signaling pathway

Chronic microglial activation endangers neuronal survival through the release of various toxic pro-inflammatory molecules; thus, negative regulators of microglial activation have been identified as potential therapeutic candidates for several neurological diseases. In this study, we investigated the inhibitory effects of an ethanol extract of Cnidium officinale rhizomes (EECO), which has been used as a herbal drug in Oriental medicine, on the production of lipopolysaccharide (LPS)-induced pro-inflammatory mediators, such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), as well as that of pro-inflammatory cytokines in BV2 microglia cells. EECO significantly inhibited the excess production of NO and PGE₂ in LPS-stimulated BV2 microglia cells. It also attenuated the expression of inducible NO synthase, cyclooxygenase-2, as well as that of pro-inflammatory cytokines, such as interleukin-1β and tumor necrosis factor-α. Moreover, EECO exhibited anti-inflammatory properties by suppressing nuclear factor-κB (NF-κB) translocation and the activation of the phosphoinositide 3-kinase/Akt pathway in LPS-stimulated BV2 cells. These results indicate that EECO exerts anti-inflammatory effects in LPS-stimulated BV2 microglial cells by inhibiting pro-inflammatory mediators and cytokine production by blocking the NF-κB pathway. These findings suggest that EECO has substantial therapeutic potential for the treatment of neurodegenerative diseases accompanied by microglial activation.

Inhibitory effects of a spinasterol glycoside on lipopolysaccharide-induced production of nitric oxide and proinflammatory cytokines via down-regulating MAP kinase pathways and NF-κB activation in RAW264.7 macrophage cells

Extracts from the leaves of Stewartia koreana are known to exhibit strong anti-inflammatory activity. Investigation of bioactive compounds from S. koreana has led to the isolation of 3-O-β-d-glucopyanosylspinasterol (spinasterol-Glc), a spinasterol glycoside. In the present study, we examined the effects of spinasterol-Glc on production of nitric oxide (NO) and proinflammatory cytokines in LPS-treated RAW264.7 macrophage cells and in mouse models. Our results showed that spinasterol-Glc inhibited the production of NO and proinflammatory cytokines such as TNF-α, IL-6 and IL-1β in dose-dependent manners in LPS-treated RAW264.7 cells. Spinasterol-Glc inhibited the expression of iNOS and the proinflammatory cytokine genes. Spinasterol-Glc also inhibited phosphorylation of IκB-α and IKKα/β as well as translocation of NF-κB to the nucleus. We demonstrated that spinasterol-Glc reduced transcription of the NF-κB minimal promoter and NF-κB DNA binding activity. Administration of the spinasterol-Glc significantly decreased the plasma levels of these inflammatory mediators including TNF-α, IL-6 and IL-1β in LPS-injected mice and improved survival of septic mice with lethal endotoxemia. These results suggest that spinasterol-Glc has effective inhibitory effects on production of inflammatory mediators via inhibition of MAP kinases/NF-κB activities, and can be used as a potential anti-inflammatory agent for the prevention and treatment of inflammatory diseases.

Neurogenic bowel dysfunction in patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease

Exciting new features have been described concerning neurogenic bowel dysfunction, including interactions between the central nervous system, the enteric nervous system, axonal injury, neuronal loss, neurotransmission of noxious and non-noxious stimuli, and the fields of gastroenterology and neurology. Patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease present with serious upper and lower bowel dysfunctions characterized by constipation, incontinence, gastrointestinal motor dysfunction and altered visceral sensitivity. Spinal cord injury is associated with severe autonomic dysfunction, and bowel dysfunction is a major physical and psychological burden for these patients. An adult myelomeningocele patient commonly has multiple problems reflecting the multisystemic nature of the disease. Multiple sclerosis is a neurodegenerative disorder in which axonal injury, neuronal loss, and atrophy of the central nervous system can lead to permanent neurological damage and clinical disability. Parkinson's disease is a multisystem disorder involving dopaminergic, noradrenergic, serotoninergic and cholinergic systems, characterized by motor and non-motor symptoms. Parkinson's disease affects several neuronal structures outside the substantia nigra, among which is the enteric nervous system. Recent reports have shown that the lesions in the enteric nervous system occur in very early stages of the disease, even before the involvement of the central nervous system. This has led to the postulation that the enteric nervous system could be critical in the pathophysiology of Parkinson's disease, as it could represent the point of entry for a putative environmental factor to initiate the pathological process. This review covers the data related to the etiology, epidemiology, clinical expression, pathophysiology, genetic aspects, gastrointestinal motor dysfunction, visceral sensitivity, management, prevention and prognosis of neurogenic bowel dysfunction patients with these neurological diseases. Embryological, morphological and experimental studies on animal models and humans are also taken into account.

Th17 cell, the new player of neuroinflammatory process in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease characterized by recurrent episodes of demyelination and axonal lesion mediated by CD4(+) T cells with a proinflammatory Th1 and Th17 phenotype, macrophages, and soluble inflammatory mediators. Identification of Th17 cells led to breaking the dichotomy of Th1/Th2 axis in immunopathogenesis of autoimmune diseases such as MS, and its experimental model, experimental autoimmune encephalomyelitis (EAE). Th17 cells are characterized by expression of retinoic acid-related orphan receptor (ROR)γt and signal transducer and activator of transcription 3 (STAT3) factors. Th17-produced cytokine profile including interleukin (IL)-17, IL-6, IL-21, IL-22, IL-23 and tumour necrosis factor (TNF)-α, which have proinflammatory functions, suggests it as an important factor in immunopathogenesis of MS, because the main feature of MS pathophysiology is the neuroinflammatory reaction. The blood brain barrier (BBB) disruption is an early and central event in MS pathogenesis. Autoreactive Th17 cells can migrate through the BBB by the production of cytokines such as IL-17 and IL-22, which disrupt tight junction proteins in the central nervous system (CNS) endothelial cells. Consistent with this observation and regarding the wide range production of proinflammatory cytokines and chemokines by Th17 cells, it is expected that Th17 cell to be as a potent pathogenic factor in disease immunopathophysiology. Th17-mediated inflammation is characterized by neutrophil recruitment into the CNS and neurons killing. However, the majority of our knowledge about the role of Th17 in MS pathogenesis is resulted in investigation into EAE animal models. In this review, we intend to focus on the newest information regarding the precise role of Th17 cells in immunopathogenesis of MS, and its animal model, EAE.