Hippocampal neurodegeneration in experimental autoimmune encephalomyelitis (EAE): potential role of inflammation activated myeloperoxidase

Brain inflammation in experimental autoimmune encephalomyelitis induced in Dark Agouti rats with spinal cord homogenate

We have recently characterized experimental autoimmune encephalomyelitis (EAE) induced in DA rats with spinal cord homogenate without complete Freund's adjuvant (CFA). The main advantage of this multiple sclerosis model is the lack of CFA-related confounding effects which represent the major obstacles in translating findings from EAE to multiple sclerosis. Here, antigen specificity of the cellular and humoral immune response directed against the central nervous system was explored. The reactivity of T and B cells to myelin basic protein, myelin oligodendrocyte glycoprotein, and β-synuclein was detected. Having in mind that reactivity against β-synuclein was previously associated with autoimmunity against the brain, the infiltration of immune cells into different brain compartments, i.e. pons, cerebellum, hippocampus, and cortex was determined. T cell infiltration was observed in all structures examined. This finding stimulated investigation of the effects of immunization on DA rat behavior using the elevated plus maze and the open field test. Rats recovered from EAE displayed increased anxiety-like behavior. These data support CFA-free EAE in DA rats as a useful model for multiple sclerosis research.

Anti-inflammatory, antioxidant and anti-mitophagy effects of trans sodium crocetinate on experimental autoimmune encephalomyelitis in BALB/C57 mice

Multiple sclerosis (MS) is an autoimmune disorder characterized by the degeneration of myelin and inflammation in the central nervous system. Trans sodium crocetinate (TSC), a novel synthetic carotenoid compound, possesses antioxidant, anti-inflammatory and neuroprotective effects. This study aimed to evaluate the protective effects of TSC against the development of experimental autoimmune encephalomyelitis (EAE), a well-established model for MS. Female BALB/C57 mice were divided into different groups, including control, EAE, vehicle, TSC-treated (25, 50, and 100 mg/kg, administered via gavage) + EAE, methyl prednisone acetate + EAE, and TSC-treated (100 mg/kg, administered via gavage for 28 days) groups. EAE was induced using MOG35-55, complete Freund's adjuvant, and pertussis toxin. In the mice spinal cord tissues, the oxidative markers (GSH and MDA) were measured using spectrophotometry and histological evaluation was performed. Mitophagic pathway proteins (PINK1and PARKIN) and inflammatory factors (IL-1β and TNF-α) were evaluated by western blot. Following 21 days post-induction, EAE mice exhibited weight loss, and the paralysis scores increased on day 13 but recovered after TSC (100 mg/kg) administration on day 16. Furthermore, TSC (50 and 100 mg/kg) reversed the altered levels of MDA and GSH in the spinal cord tissue of EAE mice. TSC (100 mg/kg) also decreased microgliosis, demyelination, and the levels of inflammatory markers IL-1β and TNF-α. Notably, TSC (100 mg/kg) modulated the mitophagy pathway by reducing PINK1 and Parkin protein levels. These findings demonstrate that TSC protects spinal cord tissue against EAE-induced MS through anti-inflammatory, antioxidant, and anti-mitophagy mechanisms.

Ameliorative effects of acetyl-L-carnitine on corpus callosum and functional recovery in demyelinated mouse model

AIM

Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disease of the central nervous system. Oxidative stress via distinct pathobiological pathways plays a pivotal role in the formation and persistence of MS lesions. Acetyl-L-carnitine (ALC) facilitates the uptake of acetyl coenzyme-A into the mitochondria by a fatty acid oxidation process. ALC could be a therapeutic antioxidant in the myelin repair process. This study explored the potential neuroprotective effects of ALC in cuprizone (CPZ) intoxicated mice.

MATERIALS AND METHODS

Thirty male C57BL/6 mice were divided into three groups. The control animals received a normal diet. The CPZ and CPZ + ALC groups were fed with a 0.2% cuprizone diet for 12 weeks. In the CPZ + ALC group, animals received ALC (300 mg/kg/day) from the 10th -12th weeks. Animals were evaluated functionally by beam walking test (BWT) weekly. Eventually, the corpus callosum (CC) was extracted for histological, biochemical, and molecular studies.

RESULTS

BWT data showed ALC significantly improves balance and gait in the demyelinating mouse model. Histological staining represented ALC effectively increased remyelination in the CC. Biochemical evaluations demonstrated ALC decreased the malondialdehyde level with a parallel increase in the reduced glutathione and catalase activity levels in the CC. Molecular analysis revealed that ALC significantly increased the expression of oligodendrocyte transcription-2 (Olig-2) and Poly lipoproteins (Plp) genes in the CC.

CONCLUSIONS

ALC improved balance and motor coordination in the demyelinated mouse model. It may be by reducing the levels of free radicals and increasing the expression of Olig-2 and Plp as myelin-related genes.

Ocimum sanctum L water extract: In-situ green synthesis of zinc oxide nanoparticles for treatment of rheumatoid arthritis: Preclinical study

BACKGROUND AND OBJECTIVE

Rheumatoid arthritis is a chronic progressive autoimmune disorder, characterised by destruction of cartilage and under line bones. Though exact etiology of rheumatoid arthritis (RA) remains unknown. It is believed that alteration in control of cellular or molecular responses is involved in the chronic inflammation. Earlier in RA patients it was observed the circulating RA specific biomarkers and immunoglobulin deposits in the synovial joints. Zinc Oxide Nanoparticles (ZnO NPs) is used as an anti-inflammatory and anticancer agent, however there is nil/very less scientific data shows the anti-arthritic activity of green synthesis ZnO nanoparticles (Ocimum sanctum water extract in-situ synthesis of ZnO NPs having active compound Caffeic acid and Rosmerinic acid). Hence, the present activity was planned to assess the anti-arthritic activity of ZnO NPs in CIA rats.

METHODS

Arthritis in rats were induced by subcutaneous injection of collagen type II (CII) (200 µl) at the base of tail on day 0 followed by booster dose on day 14. ZnO NPs were given (2 mg/kg b.wt./day) orally for 20 days. At the end of the study serum, joint homogenate was used to assess the level of biomarkers (RF, a-CCP, a-CII and CRP) and inflammatory mediators. In addition, m-RNA expression of various genes such as Nuclear factor-kB (NF-kB), inflammatory mediators like tumour necrosis factor-α (TNF-α), cyclooxygenase-2 (COX-2) etc. were assayed in joint tissue. Finally all these biochemical and molecular results were confirmed by microscopic study of joint tissue.

RESULTS

ZnO NPs, treated rats showed decrease in inflammation and clinical severity. This was related with decrease in the level of biomarkers (like RF, a-CCP and CRP), inflammatory mediators (TNF-α, COX-2) and activity of transcription factor NF-kB. All these findings were positively correlated with microscopic analysis of joint tissue that showed reduced inflammation and bone erosion in treated group.

CONCLUSION

This study validates the anti-arthritic activity of ZnO NPs as it mitigates the arthritis related symptoms in CIA rats.

Neuroprotective mechanism of Ajugarin-I against Vincristine-Induced neuropathic pain via regulation of Nrf2/NF-κB and Bcl2 signalling

Vincristine (VCR) is a well-known chemotherapeutic agent that frequently triggers neuropathic pain. Ajugarin-I (Aju-I) isolated from Ajuga bracteosa exerts antioxidant, anti-inflammatory, and neuroprotective properties. The present study was designed to investigate the ameliorative potential of Aju-I against VCR-induced neuropathic pain and explored the underlying mechanism involved. The neuroprotective potential of Aju-I was first confirmed against hydrogen peroxide (H₂O₂)-induced cytotoxicity and oxidative stress in PC12 cells. For neuropathic pain induction, vincristine was given intraperitoneally (i.p.) into adult male albino mice (BALB/c) of the same age (8-12 weeks old) for 10 days (days 1-10). Aju-I (1 and 5 mg/kg) doses were administered from day 11 to 21 intraperitoneally (i.p.) after the neuropathic induction. Initially, behavioral tests such as thermal hyperalgesia, mechanical allodynia, and cold allodynia were performed to investigate the antinociceptive potential of Ajugarin-I (1 and 5 mg/kg, b.w). The nuclear factor-erythroid factor 2-related factor 2(Nrf2), nuclear factor-κB (NF-κB), BCL2-associated × protein (Bax), and B-cell-lymphoma-2 (Bcl-2) signaling proteins were determined by immunohistochemistry and western blot. Additionally, inflammatory cytokines, antioxidant, and oxidative stress parameters were also measured in the spinal cord and sciatic nerve. The behavioral results demonstrated that Aju-I (5 mg/kg) markedly alleviated VCR-induced neuropathic pain behaviors including hyperalgesia and allodynia. It reversed the histological alterations caused by VCR in the sciatic nerve, spinal cord, and brain. It significantly alleviated oxidative stress and inflammation by regulating the immunoreactivity of Nrf2/NF-κB signaling. It suppressed apoptosis by regulating the immunoreactivity of Bcl-2/Bax and Caspase-3. The flow cytometry and comet analysis also confirmed its anti-apoptotic potential. It considerably improved the antioxidant status and mitigated VCR-induced inflammatory cytokines. High-performance liquid chromatography (HPLC) analysis indicated that Aju-I crosses the blood-brain barrier (BBB) and penetrated the brain tissue. These findings suggest that Aju-I treatment inhibited vincristine-induced neuropathy via regulation of Nrf2/NF-κB and Bcl2 signaling.

Anti-nociceptive effects of magnolol via inhibition of TRPV1/P2Y and TLR4/NF-κB signaling in a postoperative pain model

AIMS

The current study explored the anti-nociceptive activity of magnolol in post-incisional inflammatory nociceptive pain.

MAIN METHODS

Preliminary, the anti-inflammatory, antioxidant, and cytoprotective potential of magnolol were confirmed against hydrogen peroxide (H₂O₂)-induced PC12 cells. Next, an in-vivo model of planter incision surgery was established in BALB/c mice. Tramadol 50 mg/kg intraperitoneal (i.p.) and magnolol (0.1, 1, 10 mg/kg i.p. + 10 mg/kg intra planter) were administered after plantar incision surgery and behavior parameters were measured.

KEY FINDINGS

The results indicate that magnolol significantly suppressed post-incision-induced mechanical allodynia, thermal hyperalgesia, and paw edema. Magnolol promisingly inhibited post-incision induces nitric oxide (NO), malondialdehyde (MDA), eosinophil peroxidase (EPO), and neutrophil infiltration. Magnolol strongly attenuated post-incision inducing the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inhibited deoxyribonucleic acid (DNA) fragmentation. Magnolol markedly reverses post-incisional histopathological changes and biochemical composition of the incised paw. Magnolol markedly down-regulated post-incisional increase expression of transient receptor potential vanilloid 1 (TRPV1), purinergic (P2Y) nociceptors as well as toll-like receptor 4 (TLR4), nuclear factor kappa light chain enhancer of activated B cell (NF-κB), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) while upregulating the expression of inhibitor of nuclear kappa B alpha (IκB-α).

SIGNIFICANCE

The present study strongly suggests that magnolol significantly suppressed post-incisional inflammatory nociceptive pain by targeting TRPV1/P2Y and TLR4/NF-κB signaling.

The role of neutrophils in the dysfunction of central nervous system barriers

Leukocyte migration into the central nervous system (CNS) represents a central process in the development of neurological diseases with a detrimental inflammatory component. Infiltrating neutrophils have been detected inside the brain of patients with several neuroinflammatory disorders, including stroke, multiple sclerosis and Alzheimer’s disease. During inflammatory responses, these highly reactive innate immune cells can rapidly extravasate and release a plethora of pro-inflammatory and cytotoxic factors, potentially inducing significant collateral tissue damage. Indeed, several studies have shown that neutrophils promote blood-brain barrier damage and increased vascular permeability during neuroinflammatory diseases. Recent studies have shown that neutrophils migrate into the meninges and choroid plexus, suggesting these cells can also damage the blood-cerebrospinal fluid barrier (BCSFB). In this review, we discuss the emerging role of neutrophils in the dysfunction of brain barriers across different neuroinflammatory conditions and describe the molecular basis and cellular interplays involved in neutrophil-mediated injury of the CNS borders.

Magnolol prevented brain injury through the modulation of Nrf2-dependent oxidative stress and apoptosis in PLP-induced mouse model of multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated chronic inflammatory demyelinating disease of the central nervous system (CNS). The aim of the current study was to investigate the effects of magnolol in an experimental autoimmune encephalomyelitis (EAE) model of MS in female mice. Magnolol (0.1, 1, and 10 mg/kg) was administered once daily for 21 days after immunization of mice. Magnolol post-immunization treatment significantly reversed clinical scoring, EAE-associated pain parameters, and motor dysfunction in a dose-dependent manner. Magnolol treatment significantly inhibited oxidative stress by reducing malondialdehyde (MDA), nitric oxide (NO) production, and myeloperoxidase (MPO) activity while enhancing the level of antioxidants such as reduced glutathione (GSH), glutathione-S-transferase (GST), catalase, and superoxide dismutase (SOD) in the brain and spinal cord. It reduced cytokine levels in the brain and spinal cord. It suppressed CD8+ T cells frequency in the spleen tissue. Magnolol remarkably reversed the EAE-associated histopathology of the brain and spinal cord tissue. Magnolol significantly intensifies the antioxidant defense system by enhancing the expression level of nuclear factor erythroid 2-related factor (Nrf2) while decreasing the expression of inducible nitric oxide synthase (iNOS) and cleaved-caspase-3 in the brain. Molecular docking results showed that magnolol possesses a better binding affinity for Nrf2, iNOS, and caspase-3 proteins. Taken together, the present study demonstrated that magnolol has significant neuroprotective properties in EAE via inhibition of oxidative stress.

The Effects of Incensole Acetate on Neuro-inflammation, Brain-Derived Neurotrophic Factor and Memory Impairment Induced by Lipopolysaccharide in Rats

Incensole acetate (IA) is a major component of Boswellia serrata resin that has been shown to have anti-inflammatory, anti-oxidant and neuroprotective properties. The present study determined the effect of IA on lipopolysaccharide (LPS)-induced memory impairment, and hippocampal cytokines and oxidative stress indicators level. We used 32 Wistar rats (220-250 g weight) randomly divided into four groups. The control group, which only received the saline-diluted DMSO (vehicle); LPS group which received LPS and was treated with the vehicle; and two IA-treated groups which received 2.5 or 5 mg/ kg IA before LPS injection. Morris water maze (MWM) and passive avoidance (PA) tests were performed. Finally, the brains were removed and were used to assess cytokines levels and oxidative stress status. Compared to the LPS group, IA administration reduced the time spent and path traveled to reach the hidden platform during 5 days of learning in MWM while increased the time spent in the target quadrant in the probe test. Moreover, IA increased latency while decreased entry number and time spent in the dark chamber of PA test compared to the LPS group. Additionally, pre-treatment with IA attenuated interleukin(IL)-6, tumor necrosis alpha (TNF-α), glial fibrillary acidic protein (GFAP), malondialdehyde (MDA) and nitric oxide (NO) metabolites levels while increased those of IL-10, total thiol, superoxide dismutase (SOD), catalase (CAT) and brain-derived neurotrophic factor (BDNF). Our results indicated that IA improved LPS-induced learning and memory impairments. The observed effects seem to be mediated via a protective activity against neuro-inflammation and brain tissue oxidative damage and through improving BDNF.

Suppression of TRPV1/TRPM8/P2Y Nociceptors by Withametelin via Downregulating MAPK Signaling in Mouse Model of Vincristine-Induced Neuropathic Pain

Vincristine (VCR) is a widely used chemotherapy drug that induced peripheral painful neuropathy. Yet, it still lacks an ideal therapeutic strategy. The transient receptor potential (TRP) channels, purinergic receptor (P2Y), and mitogen-activated protein kinase (MAPK) signaling play a crucial role in the pathogenesis of neuropathic pain. Withametelin (WMT), a potential Phytosteroid isolated from datura innoxa, exhibits remarkable neuroprotective properties. The present investigation was designed to explore the effect of withametelin on VCR-induced neuropathic pain and its underlying molecular mechanism. Initially, the neuroprotective potential of WMT was confirmed against hydrogen peroxide (H₂O₂)-induced PC12 cells. To develop potential candidates for neuropathic pain treatment, a VCR-induced neuropathic pain model was established. Vincristine (75 μg/kg) was administered intraperitoneally (i.p.) for 10 consecutive days (day 1-10) for the induction of neuropathic pain. Gabapentin (GBP) (60 mg/kg, i.p.) and withametelin (0.1 and 1 mg/kg i.p.) treatments were given after the completion of VCR injection on the 11th day up to 21 days. The results revealed that WMT significantly reduced VCR-induced pain hypersensitivity, including mechanical allodynia, cold allodynia, and thermal hyperalgesia. It reversed the VCR-induced histopathological changes in the brain, spinal cord, and sciatic nerve. It inhibited VCR-induced changes in the biochemical composition of the myelin sheath of the sciatic nerve. It markedly downregulated the expression levels of TRPV1 (transient receptor potential vanilloid 1); TRPM8 (Transient receptor potential melastatin 8); and P2Y nociceptors and MAPKs signaling, including ERK (Extracellular Signal-Regulated Kinase), JNK (c-Jun N-terminal kinase), and p-38 in the spinal cord. It suppressed apoptosis by regulating Bax (Bcl2-associated X-protein), Bcl-2 (B-cell-lymphoma-2), and Caspase-3 expression. It considerably attenuated inflammatory cytokines, oxidative stress, and genotoxicity. This study suggests that WMT treatment suppressed vincristine-induced neuropathic pain by targeting the TRPV1/TRPM8/P2Y nociceptors and MAPK signaling.

New insights in the mechanisms of impaired redox signaling and its interplay with inflammation and immunity in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune neurological disease characterized by chronic inflammation of the central nervous system (CNS), leading to demyelination and axonal damage and resulting in a range of physical, mental or even psychiatric symptoms. Key role of oxidative stress (OS) in the pathogenesis of MS has been suggested, as indicated by the biochemical analysis of cerebrospinal fluid and blood samples, tissue homogenates, and animal models of multiple sclerosis. OS causes demyelination and neurodegeneration directly, by oxidation of lipids, proteins and DNA but also indirectly, by inducing a dysregulation of the immunity and favoring the state of pro-inflammatory response. In this review, we discuss the interrelated mechanisms of the impaired redox signaling, of which the most important are inflammation-induced production of free radicals by activated immune cells and growth factors, release of iron from myelin sheath during demyelination and mitochondrial dysfunction and consequent energy failure and impaired oxidative phosphorylation. Review also provides an overview of the interplay between inflammation, immunity and OS in MS. Finally, this review also points out new potential targets in MS regarding attenuation of OS and inflammatory response in MS.

Effect of Vaccinium macrocarpon on MK-801-induced psychosis in mice

OBJECTIVES

This study was aimed to investigate the effect of aqueous cranberry extract (ACE) on MK-801-induced psychosis in mice.

MATERIALS AND METHODS

MK-801-treated mice were administered ACE (1 and 2 g/kg, p.o.) for 14 days. Various behavioral parameters and neurochemical estimations such as dopamine (DA), 5-hydroxytryptamine (5-HT), norepinephrine (NE), gamma-aminobutyric acid (GABA), glutamate, and glycine as well as markers of oxidative stress such as nitrite levels were measured.

RESULTS

Psychosis-induced mice showed a significant elevation of immobility time in forced swim test, locomotor activity, and reduction in time of permanency in rota-rod test, escape latency time in Cook's pole test while treatment with ACE showed a significant alteration in above-mentioned behavioral parameters in MK-801-induced psychosis. Moreover, MK-801-induced psychosis in the mice showed a significant increase in DA, 5-HT, and NA levels and decrease in GABA, glutamate, and glycine levels in the brain. In contrast, treatment with ACE at both doses remarkably altered the neurochemical parameters. In addition, ACE-treated mice showed a substantial reduction in acetylcholinesterase, D-amino acid oxidase enzyme activity, and nitrite levels which were elevated by the administration of MK-801.

CONCLUSIONS

Treatment with ACE once for 14 days (1 and 2 g/kg) significantly ameliorated the behavioral symptoms in experimentally induced psychosis by virtue of neuromodulation and decreased oxidative stress.

Myeloperoxidase and Neurological Disorder: A Crosstalk

Myeloperoxidase (MPO) is a protein present in azurophilic granules, macrophages, and neutrophils that are released into extracellular fluid (ECF) during inflammation. MPO releases hypochlorous acid (HOCl) and other chlorinated species. It is derived from hydrogen peroxide (H₂O₂) showing response during inflammatory conditions and plays a role in the immune defense against pathogens. MPO may show unwanted effects by indirectly increasing the formation of reactive nitrogen species (RNS), reactive oxygen species (ROS), and tumor necrosis factor alpha (TNF-α) leading to inflammation and oxidative stress. As neuroinflammation is one of the inevitable biological components among most of neurological disorders, MPO and its receptor may be explored as candidates for future clinical interventions. The purpose of this review is to provide an overview of the pathophysiological characteristics of MPO and further explore the possibilities to target it for clinical use. Targeting MPO is promising and may open an avenue to act as a biomarker for diagnosis with defined risk stratification in patients with various neurological disorders.

The neuroprotective effect of mesenchymal stem cells on an experimentally induced model for multiple sclerosis in mice

Multiple sclerosis (MS) is a chronic autoimmune demyelinating neurodegenerative central nervous system disorder. The aim of the present study was to investigate the prophylactic effect exerted by the one-time intraperitoneal injection of mesenchymal stem cells (MSCs) 1 × 10⁶ and 14-day intraperitoneal injection of methylprednisolone (MP) 40 mg/kg in an experimental autoimmune encephalomyelitis (EAE). EAE was induced by intradermal injection of rat spinal cord homogenate with complete Freund's adjuvant in Swiss mice. Results of MSCs and MP-treated mice showed a significantly milder disease and fewer clinical scores compared to control mice. They suppressed tumor necrosis factor-alpha and myeloperoxidase and increased interleukin 10, whereas thiobarbituric acid reactive substances and nitric oxide brain contents were reduced to comparable levels between treatment groups. Brain content of GSH was significantly higher in MSCs-treated mice than control mice. It is evident that MSCs have relevant prophylactic effect in an animal model of MS and might represent a valuable tool for stem cell based therapy in MS.

Anti-arthritogenic and cardioprotective action of hesperidin and daidzein in collagen-induced rheumatoid arthritis

Atherosclerosis has been linked to chronic inflammatory processes. Changes in the levels of lipoproteins, especially low-density lipoprotein or its variants, as well as inflammatory markers are risk factors for the atherosclerosis. In the present study, an experimental model of rheumatoid arthritis was developed by administrating collagen suspension intradermally in the tail region of Wistar albino rats. At the same time, a suspension of hesperidin (50 mg/kg body weight) and daidzein (20 mg/kg body weight) was orally administrated. The compounds were given in the morning and evening for 21 days. Levels of inflammatory markers in the homogenate of knee joints of experimental rats as well as plasma lipoproteins were investigated. The administration of hesperidin and daidzein caused significant (p < 0.001) decrease in articular elastase activity, TNF-α, and malondialdehyde levels. Further, arthritis scoring and histological findings supported the anti-inflammatory actions of the test compounds. Interestingly, the test compounds also lowered the plasma low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and triglyceride but increased the level of high-density lipoprotein cholesterol. The test compounds thus ameliorated the risk factors of atherosclerosis. Furthermore, antioxidant roles of hesperidin as well as daidzein were evident from decrease in free radical load demonstrated as increase in total antioxidant level in plasma of arthritic animals treated with hesperidin and daidzein. In a separate in vitro experiment, enhanced free radical scavenging activity of hesperidin was demonstrated against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid. The anti-inflammatory, hypolipidemic, and antioxidant actions of the naturally occurring test compounds, particularly hesperidin, seem to be quite effective against rheumatoid arthritis and atherosclerosis. Thus, their consumption may be helpful in prevention or at least delaying the onset of these diseases in susceptible individuals.

Myeloperoxidase: Bridging the gap in neurodegeneration

Neurodegenerative conditions present a group of complex disease pathologies mostly due to unknown aetiology resulting in neuronal death and permanent neurological disability. Any undesirable stress to the brain, disrupts homeostatic balance, through a remarkable convergence of pathophysiological changes and immune dysregulation. The crosstalk between inflammatory and oxidative mechanisms results in the release of neurotoxic mediators apparently spearheaded by myeloperoxidase derived from activated microglia, astrocytes, neurons as well as peripheral inflammatory cells. These isolated entities combinedly have the potential to flare up and contribute significantly to neuropathology and disease progression. Recent, clinicopathological evidence support the association of myeloperoxidase and its cytotoxic product, hypochlorous acid in a plethora of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, Multiple sclerosis, Stroke, Epilepsy etc. But the biochemical and mechanistic insights into myeloperoxidase mediated neuroinflammation and neuronal death is still an uncharted territory. The current review outlines the emerging recognition of myeloperoxidase in neurodegeneration, which may offer novel therapeutic and diagnostic targets for neurodegenerative disorders.

Inhibition of myeloperoxidase at the peak of experimental autoimmune encephalomyelitis restores blood-brain barrier integrity and ameliorates disease severity

Oxidative stress is thought to contribute to disease pathogenesis in the central nervous system (CNS) disease multiple sclerosis (MS). Myeloperoxidase (MPO), a potent peroxidase that generates toxic radicals and oxidants, is increased in the CNS during MS. However, the exact mechanism whereby MPO drives MS pathology is not known. We addressed this question by inhibiting MPO in mice with experimental autoimmune encephalomyelitis (EAE) using our non-toxic MPO inhibitor N-acetyl lysyltyrosylcysteine amide (KYC). We found that therapeutic administration of KYC for 5 days starting at the peak of disease significantly attenuated EAE disease severity, reduced myeloid cell numbers and permeability of the blood-brain barrier. These data indicate that inhibition of MPO by KYC restores blood-brain barrier integrity thereby limiting migration of myeloid cells into the CNS that drive EAE pathogenesis. In addition, these observations indicate that KYC may be an effective therapeutic agent for the treatment of MS. We propose that during experimental autoimmune encephalomyelitis (EAE) onset macrophages and neutrophils migrate into the CNS and upon activation release myeloperoxidase (MPO) that promotes disruption of the blood-brain barrier (BBB) and disease progression. KYC restores BBB function by inhibiting MPO activity and in so doing ameliorates disease progression.

Anti-endotoxin effects of terpenoids fraction from Hygrophila auriculata in lipopolysaccharide-induced septic shock in rats

CONTEXT

Hygrophila auriculata (K. Schum) Heine (Acanthaceae) has been traditionally used for the treatment of various ailments such as inflammation, rheumatism, jaundice and malaria.

OBJECTIVE

The present study aims to separate terpenoid fraction (TF) from alcohol (70%) extract of the whole plant of Hygrophila auriculata and assess its anti-inflammatory activity.

MATERIALS AND METHODS

HPTLC analysis of TF was performed for the estimation of lupeol. Edema was induced in Wistar albino rats by subplanter injection of 0.1 ml of 1% (w/v) carrageenan into the right hind paw after 1 h of TF administration (100 and 200 mg/kg oral). Septic shock was induced by intraperitoneal administration of LPS (100 μg/kg) in rats and interleukins (IL-1β and IL-6), tumor necrosis factor (TNF-α), superoxide dismutase (SOD), lipid peroxidation (LPO), and nitric oxide (NO) were measured in serum. AutoDock 4.2 was used for molecular docking.

RESULTS

Administration of TF significantly (p < 0.005) restored the serum levels of cytokines, LPO (7.77 ± 0.034 versus 4.59 ± 0.059 nmole of TBARS), NO (9.72 ± 0.18 versus 4.15 ± 0.23 µmol nitrite/mg of wet tissue), and SOD (4.89 ± 0.036 versus 7.83 ± 0.033 Unit/mg protein) compared with the LPS-challenged rats. Analysis of in silico results revealed that TNF-α is the most appropriate target in eliciting anti-inflammatory activity.

CONCLUSION

The present findings suggest that TF of Hygrophila auriculata possesses great promise as an anti-inflammatory agent which may be due to its antioxidant effect. Molecular docking results could be exploited for lead optimization and development of suitable treatment of inflammatory disorders.

Somatic antigens of tropical liver flukes ameliorate collagen-induced arthritis in wistar rats

Parasitic helminths polarize immune response of their vertebrate hosts towards anti-inflammatory Th2 type and therefore it is hypothesized that they may suppress the inflammatory conditions in autoimmune disorders. The present study was undertaken to investigate in vivo immunomodulatory and therapeutic potential of somatic antigens (Ag) of liver infecting digenetic trematodes [Fasciola gigantica (Fg) and Gigantocotyle explanatum (Ge)] in collagen-induced arthritic (CIA) Wistar rats. The CIA rats were administered subcutaneously with different doses (50 μg, 100 μg and 150 μg) of somatic antigens of Fg and Ge, daily for 21 days, the time period required to establish infection in natural host (Bubalus bubalis). Thereafter, the control, diseased and treated rats were compared for different parameters viz. hind paw thickness; serum interleukins, IL-4 and IL-10, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ); expression level of matrix metalloproteinases (MMPs) -2, -9, -13 and nitric oxide (NO) in knee joints and patellar morphology. The CIA rats treated with different antigens, Fg-Ag and Ge-Ag, show significant amelioration of the disease by down regulation of serum TNF-α and IFN-γ (p< 0.05) and upregulation of IL-4 and IL-10 cytokines (p< 0.05); inhibition (p< 0.05) of MMPs (-2,-9,-13) and NO in knee joints and improved patellar morphology with decreased synovial hypertrophy and reduced infiltration of ploymorphonuclear cells. The activity of pro as well as active MMPs (-2 and -9) and active MMP-13 in knee joints of CIA rats was very high compared to the control and treatment groups, suggesting the extent of collagen degradation in CIA rats. Interestingly, the highest dose (150 μg) of Ge-Ag almost wiped out MMP-13 expression. The overall findings suggest that the somatic proteins of Ge-Ag appeared to be therapeutically more effective than Fg-Ag, reflecting interspecific molecular differences which could contribute to the ability of these worms to successfully ameliorate the pathology of CIA.

Amelioration of oxidative stress in the joint tissue may be the basis for the antiarthritic activity of Terminalia arjuna bark extract

AIM

In this study we have evaluated the antioxidant and antiarthritic activity of Terminalia arjuna bark extract (TABE) in collagen-induced arthritis (CIA) in rats.

METHODS

Arthritis was induced in rats by intradermal injection of the collagen-complete Freund's adjuvant emulsion. Right hind paw thickness was measured as a primary marker for severity of arthritis. Biochemical parameters such as tissue levels of superoxide dismutase (SOD), catalase, reduced glutathione (GSH), nitrites and thiobarbituric acid reactive substances (TBARS) were measured to determine the effect of treatment on antioxidant defenses. Articular elastase (ELA) level in the arthritic tissue was measured as a marker for neutrophil infiltration.

RESULT

Terminalia arjuna bark extract administration significantly inhibited the increase in paw thickness induced by immunization with collagen as compared to CIA-control animals. Further, it attenuated the fall in tissue SOD and GSH levels and mitigated the increase in tissue nitrites and TBARS levels as compared to CIA-control animals. Tissue ELA levels, which were significantly increased in the CIA-control animals as compared to normal animals were also significantly reduced by TABE administration.

CONCLUSION

Results of our study demonstrate the antioxidant and antiarthritic activity of TABE in CIA in rats. We believe that TABE could find clinical application in the management of rheumatoid arthritis and associated disorders.

Protective effects of melatonin against mitochondrial injury in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is the most prevalent inflammatory demyelinating disease of the central nervous system. Besides other pathophysiological mechanisms, mitochondrial injury is crucially involved in the development and progression of this disease. Mitochondria have been identified as targets for the peptide hormone melatonin. In the present study, we sought to evaluate the impact of oxidative stress on mitochondrial density and enzyme transcription during experimentally induced demyelination and the protective influence of melatonin. Adult male mice were fed with cuprizone for 5 weeks which caused severe demyelination of the corpus callosum (CC). Animals were simultaneously treated with melatonin by daily intra-peritoneal injections. Melatonin exposure reversed cuprizone-induced demyelination and axon protection. Transmission electron microscopy demonstrated significantly increased mitochondrial numbers and slightly increased mitochondrial size within CC axons after cuprizone exposure. Melatonin antagonized these effects and, in addition, induced the expression of subunits of the respiratory chain complex over normal control values reflecting a mechanism to compensate cuprizone-mediated down-regulation of these genes. Similarly, melatonin modulated gene expression of mitochondrial fusion and fission proteins. Biochemical analysis showed that oxidative stress induced by cuprizone was regulated by melatonin. The data implicate that melatonin abolishes destructive cuprizone effects in the CC by decreasing oxidative stress, restoring mitochondrial respiratory enzyme activity and fusion and fission processes as well as decreasing intra-axonal mitochondria accumulation.

The therapeutic effects of MSc1 nanocomplex, synthesized by nanochelating technology, on experimental autoimmune encephalomyelitic C57/BL6 mice

Purpose

Currently approved therapies for multiple sclerosis (MS) at best only slow down its progression. Therefore, it is necessary to utilize novel technologies in order to synthesize smart multifunctional structures. In the present study, for the first time we evaluated the therapeutic potential of MSc1 nanocomplex, which was designed based on novel nanochelating technology.

Materials and methods

MSc1 cell-protection capacity, with and without iron bond, was evaluated against hydrogen peroxide (H₂O₂)-induced oxidative stress in cultured rat pheochromocytoma-12 cells. The ability of MSc1 to maintain iron bond at pH ranges of 1–7 was evaluated. Nanocomplex toxicity was examined by estimating the intraperitoneal median lethal dose (LD₅₀). Experimental autoimmune encephalomyelitic mice were injected with MSc1 14 days after disease induction, when the clinical symptoms appeared. The clinical score, body weight, and disease-induced mortality were monitored until day 54. In the end, after collecting blood samples for assessing hemoglobin and red blood cell count, the brains and livers of the mice were isolated for hematoxylin and eosin staining and analysis of iron content, respectively.

Results

The results showed that MSc1 prevented H₂O₂-induced cell death even after binding with iron, and it preserved its bond with iron constant at pH ranges 1–7. The nanocomplex intraperitoneal LD₅₀ was 1,776.59 mg/kg. MSc1 prompted therapeutic behavior and improved the disabling features of experimental autoimmune encephalomyelitis, which was confirmed by decreased clinical scores versus increased body mass and 100% survival probability. It did not cause any adverse effects on hemoglobin or red blood cell count. Histopathological studies showed no neural loss or lymphocyte infiltration in MSc1-treated mice, while the hepatic iron content was also normal.

Conclusion

These results demonstrate that MSc1 could be a promising beneficial novel agent and has the capacity to be evaluated in further studies.

Boswellia serrata extract attenuates inflammatory mediators and oxidative stress in collagen induced arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease which leads to destruction of joints. Current treatment modalities for RA either produce symptomatic relief (NSAIDs) or modify the disease process (DMARDs). Though effective, their use is also limited by their side effects. As a result, the interest in alternative, well tolerated anti-inflammatory remedies has re-emerged. Our aim was to evaluate the antioxidant and antiarthritic activity of Boswellia serrata gum resin extract (BSE) in collagen induced arthritis. Arthritis was induced in male Wistar rats by collagen induced arthritis (CIA) method. BSE was administered at doses of 100 and 200mg/kg body weight once daily for 21 days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE2), and histological studies in joints. BSE was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of BSE resulted in significantly reduced levels of inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE2), and increased level of IL-10. The protective effects of BSE against RA were also evident from the decrease in arthritis scoring and bone histology. The abilities to inhibit proinflammatory cytokines and modulation of antioxidant status suggest that the protective effect of Boswellia serrata extract on arthritis in rats might be mediated via the modulation of immune system.

Quercetin prevents protein nitration and glycolytic block of proliferation in hydrogen peroxide insulted cultured neuronal precursor cells (NPCs): Implications on CNS regeneration

Survival along with optimal proliferation of neuronal precursors determines the outcomes of the endogenous cellular repair in CNS. Cellular-oxidation based cell death has been described in several neurodegenerative disorders. Therefore, this study was aimed at the identification of the potent targets of oxidative damage to the neuronal precursors and its effective prevention by a natural flavonoid, Quercetin. Neuronal precursor cells (NPCs), Nestin+ and GFAP (Glial fibrillary acidic protein)+ were isolated and cultured from adult rat SVZ (subventricular zone). These cells were challenged with a single dose of H2O2 (50μM) and/or pre-treated with different concentrations of Quercetin. H2O2 severely limited the cellular viability and expansion of the neurospheres. Cellular-oxidation studies revealed reduction in glutathione dependent redox buffering along with depletion of enzymatic cellular antioxidants that might potentiate the nitrite (NO2(-)) and superoxide anion (O2(-)) mediated peroxynitrite (ONOO(-)) formation and irreversible protein nitration. We identified depleted PK-M2 (M2 isoform of pyruvate kinase) activity and apoptosis of NPCs revealed by the genomic DNA fragmentation and elevated PARP (poly ADP ribose polymerase) activity along with increased Caspase activity initiated by severely depolarised mitochondrial membranes. However, the pre-treatment of Quercetin in a dose-response manner prevented these changes and restored the expansion of neurospheres preferably by neutralizing the oxidative conditions and thereby reducing peroxynitrite formation, protein nitration and PK-M2 depletion. Our results unravel the potential interactions of oxidative environment and respiration in the survival and activation of precursors and offer a promise shown by a natural flavonoid in the protective strategy for neuronal precursors of adult brain.

Lipidome analysis in multiple sclerosis reveals protein lipoxidative damage as a potential pathogenic mechanism

Metabolomic and lipidomic analyses have been used for the profiling of neurodegenerative processes, both in targeted and untargeted approaches. In this work we have applied these techniques to the study of CSF samples of multiple sclerosis (MS) patients (n = 9), compared with samples of non-MS individuals (n = 9) using mass-spectrometry. We have used western-blot and analyzed cell culture to confirm pathogenic pathways suggested by mass-spectrometric measurements. The results of the untargeted approach of metabolomics and lipidomics suggest the existence of several metabolites and lipids discriminating both populations. Applying targeted lipidomic analyses focused to a pathogenic pathway in MS, oxidative stress, reveal that the lipid peroxidation marker 8-iso-prostaglandin F2α is increased in CSF from MS patients. Furthermore, as lipid peroxidation exerts its pathogenical effects through protein modification, we studied the incidence of protein lipoxidation, revealing specific increases in carboxymethylated, neuroketal and malondialdehyde-mediated protein modifications in proteins of CSF from MS patients, despite the absence of their precursors glyoxal and methylglyoxal. Finally, we report that the level of neuroketal-modified proteins correlated with a hitherto unknown increased amount of autoantibodies against lipid peroxidation-modified proteins in CSF, without compensation by signaling induced by lipid peroxidation via peroxisome proliferator-activated receptor γ (PPARγ). The results, despite the limitation of being obtained in a small population, strongly suggest that autoimmunity against in situ produced epitopes derived from lipid peroxidation can be a relevant pathogenic factor in MS.

Chronological changes in inflammatory cytokines immunoreactivities in the mouse hippocampus after systemic administration of high dosage of tetanus toxin

Tetanus toxin (TeT) is an exotoxin and has a capacity for neuronal binding and internalization. In the present study, we compared changes in the immunoreactivities and protein levels of interleukin (IL-) 2 as a pro-inflammatory cytokine and IL-4 as an anti-inflammatory cytokine in the hippocampus proper (HP) and dentate gyrus (DG) after systemic treatment of 10 or 100 ng/kg TeT into mice. In this study, we could not find any neuronal damage or loss in any subregions of the hippocampus after TeT treatment. In the control groups, strong IL-2 immunoreactivity was shown in the stratum pyramidal (SP) of the HP and in the granule cell layer (GCL) of the DG. At 6 h post-treatment, IL-2 immunoreactivity was hardly detected in the SP and GCL; however, strong IL-2 immunoreactivity was shown in the stratum oriens of the HP in both the groups. Thereafter, intermediate IL-2 immunoreactivity was shown in the SP and GCL. On the other hand, intermediate IL-4 immunoreactivity was detected in the SP and GCL of the control groups. At 6 h post-treatment, IL-4 immunoreactivity in the SP and GCL was apparently increased. Thereafter, IL-4 immunoreactivity was lower than that at 6 h post-treatment. In brief, IL-2 and 4 immunoreactivities were easily detected in SP and GCL in the controls and dramatically decreased and increased at 6 h post-treatment, respectively.

Survival in MS: a randomized cohort study 21 years after the start of the pivotal IFNβ-1b trial

OBJECTIVE

To examine the effects of interferon beta (IFNβ)-1b on all-cause mortality over 21 years in the cohort of 372 patients who participated in the pivotal randomized clinical trial (RCT), retaining (in the analysis) the original randomized treatment-assignments.

METHODS

For this randomized long-term cohort study, the primary outcome, defined before data collection, was the comparison of all-cause mortality between the IFNβ-1b 250 μg and placebo groups from the time of randomization through the entire 21-year follow-up interval (intention-to-treat, log-rank test for Kaplan-Meier survival curves). All other survival outcomes were secondary.

RESULTS

After a median of 21.1 years from RCT enrollment, 98.4%(366 of 372) of patients were identified, and, of these, 81 deaths were recorded (22.1% [81 of 366]). Patients originally randomly assigned to IFNβ-1b 250 μg showed a significant reduction in all-cause mortality over the 21-year period compared with placebo (p = 0.0173), with a hazard ratio of 0.532 (95% confidence interval 0.314-0.902). The hazard rate of death at long-term follow-up by Kaplan-Meier estimates was reduced by 46.8% among IFNβ-1b 250 μg-treated patients (46.0% among IFNβ-1b 50 μg-treated patients) compared with placebo. Baseline variables did not influence the observed treatment effect.

CONCLUSIONS

There was a significant survival advantage in this cohort of patients receiving early IFNβ-1b treatment at either dose compared with placebo. Near-complete ascertainment, together with confirmatory findings from both active treatment groups, strengthens the evidence for an IFNβ-1b benefit on all-cause mortality.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that early treatment with IFNβ-1b is associated with prolonged survival in initially treatment-naive patients with relapsing-remitting multiple sclerosis.

Modulation of the oxidative stress and inflammatory cytokine response by thymoquinone in the collagen induced arthritis in Wistar rats

Thymoquinone (TQ) is the major active compound derived from Nigella sativa. Our aim of this work was to evaluate the antioxidant and antiarthritic activity of TQ in Wistar rat by collagen induced arthritis (CIA). TQ was administered at a dose of 5mgkg(-1) body weight once daily for 21days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE(2)) and histological studies in joints. TQ was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of TQ resulted in significantly reduced the levels of pro-inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE(2)) and increased level of IL-10. The protective effects of TQ against RA were also evident from the decrease in arthritis scoring and bone histology. In conclusion, the fact that TQ abolished a number of factors known to be involved in RA pathogenesis indicates that the administration of thymoquinone may have potential value in the treatment of inflammatory disease.

Biological outcome measurements for behavioral interventions in multiple sclerosis

Behavioral interventions including exercise, stress management, patient education, psychotherapy and multidisciplinary neurorehabilitation in general are receiving increasing recognition in multiple sclerosis (MS) clinical practice and research. Most scientific evaluations of these approaches have focused on psychosocial outcome measures such as quality of life, fatigue or depression. However, it is becoming increasingly clear that neuropsychiatric symptoms of MS are at least partially mediated by biological processes such as inflammation, neuroendocrine dysfunction or regional brain damage. Thus, successful treatment of these symptoms with behavioral approaches could potentially also affect the underlying biology. Rigidly designed scientific studies are needed to explore the potential of such interventions to affect MS pathology and biological pathways linked to psychological and neuropsychiatric symptoms of MS. Such studies need to carefully select outcome measures on the behavioral level that are likely to be influenced by the specific intervention strategy and should include biomarkers with evidence for an association with the outcome parameter in question. In this overview, we illustrate how biological and psychological outcome parameters can be combined to evaluate behavioral interventions. We focus on two areas of interest as potential targets for behavioral interventions: depression and fatigue.

Mimic peptides bonding specifically with the first and second extracellular loops of the CC chemokine receptor 5 derived from a phage display peptide library are potent inhibitors of experimental autoimmune encephalomyelitis

PURPOSE

To obtain mimic peptides that specifically bind with the first and second extracellular loops (ECL1, ECL2) of the CC chemokine receptor 5 (CCR5) and to study their treatment effects on experimental autoimmune encephalomyelitis (EAE) mice.

METHODS

A phage display peptide library was applied to screen peptides that bond with ECL1 and ECL2. ELISA and DNA sequence analysis were used to identify positive clones. EAE mice were treated with synthesized peptides by intraperitoneal injection.

RESULTS

Eighteen positive clones were obtained and four peptides with sequences STFTTTL, TPIPQLL, SLPLPKP and QTSSAAL were identified. These peptides could significantly protect against and reduce the severity of EAE. The infiltration of monocytes and lymphocytes into the spinal cord decreased significantly in treated mice, while abundant inflammatory cells and demyelination were observed in spinal cords of EAE mice.

CONCLUSION

CCR5 mimic peptides provided a significant protective effect to EAE mice. These potent inhibitory mimic peptides could be useful in the clinical treatment of multiple sclerosis.

Increased spontaneous apoptosis of rat primary neurospheres in vitro after experimental autoimmune encephalomyelitis

Survival of neuronal progenitors (NPCs) is a critical determinant of the regenerative capacity of brain following cellular loss. Herein, we report for the first time, the increased spontaneous apoptosis of the first acute phase of Experimental Autoimmune Encephalomyelitis (EAE) derived neurospheres in vitro. Neuronal as well as oligodendroglial loss occurs during experimental autoimmune encephalomyelitis (EAE). This loss is replenished spontaneously by the concomitant increase in the NPC proliferation evidenced by the presence of thin myelin sheaths in the remodeled lesions. However, remyelination depends upon the survival of NPCs and their lineage specific differentiation. We observed significant increase (P < 0.001) in number of BrdU (+) cells in ependymal subventricular zone (SVZ) in EAE rats. EAE derived NPCs showed remarkable increase in S-phase population which was indeed due to the decrease in G-phase progeny suggesting activation of neuronal progenitor cells (NPCs) from quiescence. However, EAE derived neurospheres showed limited survival in vitro which was mediated by the significantly (P < 0.01) depolarized mitochondria, elevated Caspase-3 (P < 0.001) and fragmentation of nuclear DNA evidenced by single cell gel electrophoresis. Our results suggest EAE induced spontaneous apoptosis of NPCs in vitro which may increase the possibility of early stage cell death in the negative regulation of the proliferative cell number and may explain the failure of regeneration in human multiple sclerosis.

Upregulation of CSPG3 accompanies neuronal progenitor proliferation and migration in EAE

The molecular identities of signals that regulate the CNS lesion remodeling remain unclear. Herein, we report for the first time that extracellular matrix chondroitin sulphate proteoglycan, CSPG3 (neurocan) is upregulated after primary inflammatory injury. EAE was induced using myelin oligodendrocyte glycoprotein (MOG) (35-55) which was characterized by massive polymorphonuclear cell infiltration and loss of myelin basic protein expression along with steep decrease of CNPase. Periventricular white matter (PVWM) and cortex presented with astrogliosis evidenced by increased Glial fibrillary acidic protein (GFAP) immunoreactivity 20 days post immunization (p.i). Neuronal progenitor cell (NPC) proliferation increased after first acute episode in the subventricular zone (SVZ), corpus callosum, and cortex, indicating migration of cells to structures other than rostral migration stream and olfactory bulb, which is indicative of cell recruitment for repair process and was confirmed by presence of thin myelin sheaths in the shadow plaques. Earlier CSPG3 has been demonstrated to impede regeneration. We observed neuroinflammation-induced up-regulation of the CSPG3 expression in two most affected regions viz. PVWM and cortex after proliferation and migration of NPCs. Our results show possible role of reactive astrogliosis in lesion remodeling and redefine the relation between inflammation and endogenous cellular repair which can aid in designing of newer therapeutic strategies.

Cytokinetics of adult rat SVZ after EAE

Cytokinetics regulating cell cycle division can be modulated by several endogenous factors. EAE (experimental autoimmune encephalomyelitis) increases proliferation of progenitor cells in the subventricular zone (SVZ). Using cumulative and single S phase labeling with 5-bromo-2-deoxyuridine, we examined cell cycle kinetics of neural progenitor cells in the SVZ after EAE. 20% of the SVZ cell population was proliferating in adjuvant control rats. However, EAE significantly increased them up to 27% and these cells had a cell cycle length (TC) of 15.6h, significantly (P<0.05) shorter than the 19 h TC in non EAE SVZ cells. Few TUNEL (+) cells were detected in the SVZ cells of adjuvant controls. EAE increased (P<0.05) TUNEL (+) nuclei in SVZ suggesting early stage progenitor cell death. Cell cycle phase analysis revealed that EAE substantially shortened the length of the G1 phase (9.6h) compared with the G1 phase of 12.25 h in adjuvant control SVZ cells (P<0.05). This reduction in G1 contributes to EAE-induced reduction of TC because no significant changes were detected on the length of S, G2 and M phases between the two groups. Our results show a surge in proliferating progenitor cells in the SVZ with concomitant increase in apoptotic cell death after EAE. Furthermore, increase in the SVZ proliferation contributes to EAE-induced neurogenesis and this increase is regulated by shortening the G1 phase. Our investigation suggests the activation of quiescent cells in SVZ to generate actively proliferating progenitors. Moreover, the increase in the cell death in proliferating population may contribute towards negative regulation of proliferative cell number and hence diminished regenerative capacity of CNS following EAE.

Inflammation, demyelination, and degeneration - recent insights from MS pathology

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system which responds to anti-inflammatory treatments in the early disease phase. However, the pathogenesis of the progressive disease phase is less well understood, and inflammatory as well as neurodegenerative mechanisms of tissue damage are currently being discussed. This review summarizes current knowledge on the interrelation between inflammation, demyelination, and neurodegeneration derived from the study of human autopsy and biopsy brain tissue and experimental models of MS.

Hippocampal CA1 atrophy and synaptic loss during experimental autoimmune encephalomyelitis, EAE

Over half of multiple sclerosis (MS) patients experience cognitive deficits, including learning and memory dysfunction, and the mechanisms underlying these deficits remain poorly understood. Neuronal injury and synaptic loss have been shown to occur within the hippocampus in other neurodegenerative disease models, and these pathologies have been correlated with cognitive impairment. Whether hippocampal abnormalities occur in MS models is unknown. Using experimental autoimmune encephalomyelitis (EAE), we evaluated hippocampal neurodegeneration and inflammation during disease. Hippocampal pathology began early in EAE disease course, and included decreases in CA1 pyramidal layer volume, loss of inhibitory interneurons and increased cell death of neurons and glia. It is interesting to note that these effects occurred in the presence of chronic microglial activation, with a relative paucity of infiltrating blood-borne immune cells. Widespread diffuse demyelination occurred in the hippocampus, but there was no significant decrease in axonal density. Furthermore, there was a significant reduction in pre-synaptic puncta and synaptic protein expression within the hippocampus, as well as impaired performance on a hippocampal-dependent spatial learning task. Our results demonstrate that neurodegenerative changes occur in the hippocampus during autoimmune-mediated demyelinating disease. This work establishes a preclinical model for assessing treatments targeted toward preventing hippocampal neuropathology and dysfunction in MS.