The good and the bad of neuroinflammation in multiple sclerosis

Optical Coherence Tomography Advanced Parameters in Patients with Multiple Sclerosis: Ophthalmological and Neurological Assessments

PURPOSE

To evaluate ophthalmological, neurological, radiological, and laboratory data in patients with multiple sclerosis (MS) and to identify new ophthalmological factors that could be helpful as biomarkers of the disease, potentially leading to an earlier prediction of disease course and disability progression.

DESIGN

Retrospective, cross-sectional-study.

METHODS

Best-corrected visual acuity (BCVA), ophthalmological biomicroscopy of the anterior segment and fundus, structural optical coherence tomography (OCT) with retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC), and OCT Angiography (OCTA) with vascular density (VD) were performed. The following clinical and neuro-radiological features were assessed: MS phenotype, disease duration, clinical severity, type of treatment, and T2-weighted lesion load plus T1-weighted Gd+-enhancing lesion number on the last brain and spinal cord MRI.

RESULTS

One hundred and six patients (212 eyes) were analyzed. Sixty-six of them (62.2 %) had MS and 40 (37.8%) were matched healthy controls (HCs). patients with MS showed lower RNFL, GCC, and VD in the radial peripapillary capillary plexus than controls in both eyes (p<0.05). By Performing a logistic regression with a distinct MS outcome for both eyes, we were able to demonstrate that the value that was most predictive of MS was the average GCC thickness (p=0.009). Regression analysis demonstrated that patients with a higher T2-weighted lesions showed a lower RNFL thickness value and reduced GCC and VD values than those with a low lesion load (p<0.01 and p<0.05, respectively). Similarly, relapsing MS patients showed lower RNFL values (p<0.05).

CONCLUSIONS

Several OCT- and OCTA-optic nerve parameters could be useful prognostic biomarkers for the MS disease course in clinical practice. However, it is necessary to do additional research with larger sample sizes in order to validate these findings.

Challenges in Diagnosis and Therapeutic Strategies in Late-Onset Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and degenerative demyelinating disease of the central nervous system of unknown etiology, which affects individuals in their early adulthood. However, nearly 5-10% of people with MS can be diagnosed at ages above 50 years old, referred to as late-onset multiple sclerosis (LOMS). Some studies have reported a distinctive presentation, clinical course, and prognosis for LOMS, implicating a different diagnostic and therapeutic approach for this population. Furthermore, similar manifestations between LOMS and other age-related conditions may lead to potential misdiagnosis and diagnostic delays, and a higher burden of multimorbidity associated with aging can further complicate the clinical picture. This review aims to explore the clinical characteristics, the disease course, and the differential diagnosis of LOMS and addresses therapeutic considerations for this population.

The significance of cerebrospinal fluid analysis in the differential diagnosis of 564 psychiatric patients: Multiple sclerosis is more common than autoimmune-encephalitis

The analysis of cerebrospinal fluid (CSF) is an essential tool for the differential diagnosis of psychiatric disorders caused by autoimmune inflammation or infections. Clear guidelines for CSF analysis are limited and mainly available for schizophrenia and dementia. Thus, insights into CSF changes in psychiatric patients largely derive from research. We analyzed the clinical and CSF data of 564 psychiatric patients without pre-existing neurological diagnoses from March 1998 to April 2020. Primary aim was to detect previously undiagnosed neurological conditions as underlying cause for the psychiatric disorder. Following CSF analysis, 8 % of patients (47/564) were diagnosed with a neurological disorder. This was the case in 12.0 % (23/193) of patients with affective disorders, 7.2 % (19/262) of patients with schizophrenia, and 4.0 % (23/193) of patients with anxiety disorders. The predominant new diagnoses were multiple sclerosis (19/47) and autoimmune encephalitis (10/47). Abnormal CSF findings without any implications for further treatment were detected in 17.0 % (94/564) of patients. Our data indicates that CSF analysis in patients suffering from psychiatric disorders may uncover underlying organic causes, most commonly multiple sclerosis and autoimmune encephalitis. Our findings imply that the incorporation of CSF analysis in routine psychiatric assessments is potentially beneficial.

Harnessing the therapeutic potential of mesenchymal stem/stromal cell-derived extracellular vesicles as a novel cell-free therapy for animal models of multiple sclerosis

Multiple sclerosis (MS) is a chronic, neuroinflammatory, and demyelinating disease of the central nervous system (CNS). Current treatments offer only limited relief from symptoms, and there is no cure. Mesenchymal stem/stromal cells (MSCs) have demonstrated therapeutic potential for MS. However, their clinical application faces challenges, including immune rejection and the potential for tumor formation. Recent studies suggest that MSCs exert their effects through extracellular vesicles (EVs) released from the cells, rather than direct cellular engraftment or differentiation. This discovery has sparked interest in the potential of MSC-derived EVs as a cell-free therapy for MS. This review explores the existing literature on the effects of MSC-EVs in animal models of MS. Administration of MSC-EVs from various tissue sources, such as bone marrow, adipose tissue, and umbilical cord, was found to reduce clinical scores and slow down disease progression in experimental autoimmune encephalomyelitis (EAE), the primary mouse model of MS. The mechanisms involved immunomodulation through effects on T cells, cytokines, CNS inflammation, and demyelination. Although the impact on CNS repair markers remained unclear, MSC-EVs exhibited the potential to modulate neuroinflammation and suppress harmful immune responses in EAE. Further studies are still required, but MSC-EVs demonstrate promising therapeutic effects for MS and warrant further exploration as a novel treatment approach.

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Drugs to Treat Neuroinflammation in Neurodegenerative Disorders

Neuroinflammation is associated with disorders of the nervous system, and it is induced in response to many factors, including pathogen infection, brain injury, toxic substances, and autoimmune diseases. Astrocytes and microglia have critical roles in neuroinflammation. Microglia are innate immune cells in the central nervous system (CNS), which are activated in reaction to neuroinflammation-inducing factors. Astrocytes can have pro- or anti-inflammatory responses, which depend on the type of stimuli presented by the inflamed milieu. Microglia respond and propagate peripheral inflammatory signals within the CNS that cause low-grade inflammation in the brain. The resulting alteration in neuronal activities leads to physiological and behavioral impairment. Consequently, activation, synthesis, and discharge of various pro-inflammatory cytokines and growth factors occur. These events lead to many neurodegenerative conditions, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis discussed in this study. After understanding neuroinflammation mechanisms and the involvement of neurotransmitters, this study covers various drugs used to treat and manage these neurodegenerative illnesses. The study can be helpful in discovering new drug molecules for treating neurodegenerative disorders.

Symmetry differences of structural connectivity in multiple sclerosis and healthy state

Focal and diffuse cerebral damages occur in Multiple Sclerosis (MS) that promotes profound shifts in local and global structural connectivity parameters, mainly derived from diffusion tensor imaging. Most of the reconstruction analyses have applied conventional tracking algorithms largely based on the controversial streamline count. For a more credible explanation of the diffusion MRI signal, we used convex optimization modeling for the microstructure-informed tractography2 (COMMIT2) framework. All multi-shell diffusion data from 40 healthy controls (HCs) and 40 relapsing-remitting MS (RRMS) patients were transformed into COMMIT2-weighted matrices based on the Schefer-200 parcels atlas (7 networks) and 14 bilateral subcortical regions. The success of the classification process between MS and healthy state was efficiently predicted by the left DMN-related structures and visual network-associated pathways. Additionally, the lesion volume and age of onset were remarkably correlated with the components of the left DMN. Using complementary approaches such as global metrics revealed differences in WM microstructural integrity between MS and HCs (efficiency, strength). Our findings demonstrated that the cutting-edge diffusion MRI biomarkers could hold the potential for interpreting brain abnormalities in a more distinctive way.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

The Importance of Managing Modifiable Comorbidities in People with Multiple Sclerosis: A Narrative Review

Multiple sclerosis (MS) is a chronic, inflammatory, degenerative demyelinating disease of the central nervous system (CNS) of unknown etiology that affects individuals in their early adulthood. In the last decade, life expectancy for people with MS (PwMS) has almost equaled that of the general population. This demographic shift necessitates a heightened awareness of comorbidities, especially the ones that can be prevented and modified, that can significantly impact disease progression and management. Vascular comorbidities are of particular interest as they are mostly modifiable health states, along with voluntary behaviors, such as smoking and alcohol consumption, commonly observed among individuals with MS. Vascular risk factors have also been implicated in the etiology of cerebral small vessel disease. Furthermore, differentiating between vascular and MS lesion load poses a significant challenge due to overlapping clinical and radiological features. This review describes the current evidence regarding the range of preventable and modifiable comorbidities and risk factors and their implications for PwMS.

From the Bush to the Brain: Preclinical Stages of Ethnobotanical Anti-Inflammatory and Neuroprotective Drug Discovery-An Australian Example

The Australian rainforest is a rich source of medicinal plants that have evolved in the face of dramatic environmental challenges over a million years due to its prolonged geographical isolation from other continents. The rainforest consists of an inherent richness of plant secondary metabolites that are the most intense in the rainforest. The search for more potent and more bioavailable compounds from other plant sources is ongoing, and our short review will outline the pathways from the discovery of bioactive plants to the structural identification of active compounds, testing for potency, and then neuroprotection in a triculture system, and finally, the validation in an appropriate neuro-inflammatory mouse model, using some examples from our current research. We will focus on neuroinflammation as a potential treatment target for neurodegenerative diseases including multiple sclerosis (MS), Parkinson's (PD), and Alzheimer's disease (AD) for these plant-derived, anti-inflammatory molecules and highlight cytokine suppressive anti-inflammatory drugs (CSAIDs) as a better alternative to conventional nonsteroidal anti-inflammatory drugs (NSAIDs) to treat neuroinflammatory disorders.

Comparison of recent updates in genetics, immunology, biomarkers, and neuroimaging of primary-progressive and relapsing-remitting multiple sclerosis and the role of ocrelizumab in the management of their refractory cases

Background

Primary-progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS) are two frequent multiple sclerosis (MS) subtypes that involve 10%-15% of patients. PPMS progresses slowly and is diagnosed later in life. Both subtypes are influenced by genetic and environmental factors such as smoking, obesity, and vitamin D insufficiency. Although there is no cure, ocrelizumab can reduce symptoms and delay disease development. RRMS is an autoimmune disease that causes inflammation, demyelination, and disability. Early detection, therapy, and lifestyle changes are critical. This study delves into genetics, immunology, biomarkers, neuroimaging, and the usefulness of ocrelizumab in the treatment of refractory patients of PPMS.

Method

In search of published literature providing up-to-date information on PPMS and RRMS, this review conducted numerous searches in databases such as PubMed, Google Scholar, MEDLINE, and Scopus. We looked into genetics, immunology, biomarkers, current breakthroughs in neuroimaging, and the role of ocrelizumab in refractory cases.

Results

Our comprehensive analysis found considerable advances in genetics, immunology, biomarkers, neuroimaging, and the efficacy of ocrelizumab in the treatment of refractory patients.

Conclusion

Early detection, timely intervention, and the adoption of lifestyle modifications play pivotal roles in enhancing treatment outcomes. Notably, ocrelizumab has demonstrated potential in symptom control and mitigating the rate of disease advancement, further underscoring its clinical significance in the management of MS.

Indoleamine 2,3-Dioxygenase as a Therapeutic Target for Alzheimer's Disease and Geriatric Depression

Neuroimmune-triggered neuroinflammation of the central nervous system is emerging as an important aetiopathogenic factor for multiple neurological disorders, including depression, dementia, Alzheimer's disease, multiple sclerosis and others. Tryptophan metabolism via the kynurenic pathway, which is initiated by the indoleamine-2,3-dioxygenase (IDO-1) enzyme, is a key regulator of the neuroimmune system and its associated neuroinflammatory effects. As discussed in this review, targeting the production of immunopathic and potentially neurotoxic kynurenine metabolites by inhibitory downregulation of IDO-1 may prove a viable target against inflammation-induced neurological conditions, particularly depression and dementia.

The Role of BDNF in Multiple Sclerosis Neuroinflammation

Multiple sclerosis (MS) is a chronic, inflammatory, and degenerative disease of the central nervous system (CNS). Inflammation is observed in all stages of MS, both within and around the lesions, and can have beneficial and detrimental effects on MS pathogenesis. A possible mechanism for the neuroprotective effect in MS involves the release of brain-derived neurotrophic factor (BDNF) by immune cells in peripheral blood and inflammatory lesions, as well as by microglia and astrocytes within the CNS. BDNF is a neurotrophic factor that plays a key role in neuroplasticity and neuronal survival. This review aims to analyze the current understanding of the role that inflammation plays in MS, including the factors that contribute to both beneficial and detrimental effects. Additionally, it explores the potential role of BDNF in MS, as it may modulate neuroinflammation and provide neuroprotection. By obtaining a deeper understanding of the intricate relationship between inflammation and BDNF, new therapeutic strategies for MS may be developed.

Human cortical spheroids with a high diversity of innately developing brain cell types

BACKGROUND

Three-dimensional (3D) human brain spheroids are instrumental to study central nervous system (CNS) development and (dys)function. Yet, in current brain spheroid models the limited variety of cell types hampers an integrated exploration of CNS (disease) mechanisms.

METHODS

Here we report a 5-month culture protocol that reproducibly generates H9 embryonic stem cell-derived human cortical spheroids (hCSs) with a large cell-type variety.

RESULTS

We established the presence of not only neuroectoderm-derived neural progenitor populations, mature excitatory and inhibitory neurons, astrocytes and oligodendrocyte (precursor) cells, but also mesoderm-derived microglia and endothelial cell populations in the hCSs via RNA-sequencing, qPCR, immunocytochemistry and transmission electron microscopy. Transcriptomic analysis revealed resemblance between the 5-months-old hCSs and dorsal frontal rather than inferior regions of human fetal brains of 19-26 weeks of gestational age. Pro-inflammatory stimulation of the generated hCSs induced a neuroinflammatory response, offering a proof-of-principle of the applicability of the spheroids.

CONCLUSIONS

Our protocol provides a 3D human brain cell model containing a wide variety of innately developing neuroectoderm- as well as mesoderm-derived cell types, furnishing a versatile platform for comprehensive examination of intercellular CNS communication and neurological disease mechanisms.

Electrophysiological Activity of Primary Cortical Neuron-Glia Mixed Cultures

Neuroinflammation plays a central role in many neurological disorders, ranging from traumatic brain injuries to neurodegeneration. Electrophysiological activity is an essential measure of neuronal function, which is influenced by neuroinflammation. In order to study neuroinflammation and its electrophysiological fingerprints, there is a need for in vitro models that accurately capture the in vivo phenomena. In this study, we employed a new tri-culture of primary rat neurons, astrocytes, and microglia in combination with extracellular electrophysiological recording techniques using multiple electrode arrays (MEAs) to determine the effect of microglia on neural function and the response to neuroinflammatory stimuli. Specifically, we established the tri-culture and its corresponding neuron-astrocyte co-culture (lacking microglia) counterpart on custom MEAs and monitored their electrophysiological activity for 21 days to assess culture maturation and network formation. As a complementary assessment, we quantified synaptic puncta and averaged spike waveforms to determine the difference in excitatory to inhibitory neuron ratio (E/I ratio) of the neurons. The results demonstrate that the microglia in the tri-culture do not disrupt neural network formation and stability and may be a better representation of the in vivo rat cortex due to its more similar E/I ratio as compared to more traditional isolated neuron and neuron-astrocyte co-cultures. In addition, only the tri-culture displayed a significant decrease in both the number of active channels and spike frequency following pro-inflammatory lipopolysaccharide exposure, highlighting the critical role of microglia in capturing electrophysiological manifestations of a representative neuroinflammatory insult. We expect the demonstrated technology to assist in studying various brain disease mechanisms.

Mechanisms of antigen-induced reversal of CNS inflammation in experimental demyelinating disease

Autoimmune central nervous system (CNS) demyelinating diseases are a major public health burden and poorly controlled by current immunosuppressants. More precise immunotherapies with higher efficacy and fewer side effects are sought. We investigated the effectiveness and mechanism of an injectable myelin-based antigenic polyprotein MMPt (myelin oligodendrocyte glycoprotein, myelin basic protein and proteolipid protein, truncated). We find that it suppresses mouse experimental autoimmune encephalomyelitis without major side effects. MMPt induces rapid apoptosis of the encephalitogenic T cells and suppresses inflammation in the affected CNS. Intravital microscopy shows that MMPt is taken up by perivascular F4/80⁺ cells but not conventional antigen-presenting dendritic cells, B cells, or microglia. MMPt-stimulated F4/80⁺ cells induce reactive T cell immobilization and apoptosis in situ, resulting in reduced infiltration of inflammatory cells and chemokine production. Our study reveals alternative mechanisms that explain how cognate antigen suppresses CNS inflammation and may be applicable for effectively and safely treating demyelinating diseases.

Trojan Horse Nanocapsule Enabled In Situ Modulation of the Phenotypic Conversion of Th17 Cells to Treg Cells for the Treatment of Multiple Sclerosis in Mice

Th17/Treg imbalance is closely related to the occurrence and development of multiple sclerosis (MS), and the transdifferentiation of Th17 cells into Treg cells may contribute to the resolution of inflammation, presenting a therapeutic strategy for MS. To modulate this phenotypic shift in situ, a "Trojan horse"-like hybrid system, nanocapsule-coupled Th17 cells, is reported for MS treatment. Following intravenous injection into MS mice, the hybrid system efficiently transmigrates across the blood-brain barrier and homes to the inflamed MS niche. (Aminooxy)-acetic acid, a transdifferentiation inducer, is locally released upon the production of ROS and in turn taken up by Th17 cells. It is demonstrated that the Trojan horse hybrid system enables in situ phenotypic transdifferentiation of Th17 cells into anti-inflammatory Treg cells. This phenotypic conversion leads to a domino-like immune response that is conducive to MS therapy. Overall, this work highlights a new pathway for accurate modulation of the phenotypes of adoptively transferred cells in situ, from proinflammatory to anti-inflammatory for MS therapy, and may be broadly applicable for patients suffering from other autoimmune diseases.

Multiple Sclerosis and Autoimmune Comorbidities

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system characterized by broad inter- and intraindividual heterogeneity and different prognoses. Multisystem comorbidities are frequent features in people with MS (PwMS) and can affect treatment choices, quality of life, disability and mortality. In this scenario, autoimmune comorbidities play a cardinal role for several reasons, such as the implication on MS pathogenesis, diagnostic delay, disease activity, disability progression, brain atrophy, and treatment choice. However, the impact of an autoimmune comorbid condition on MS is not fully elucidated. This review aims to summarize the currently available data on the incidence and prevalence of autoimmune diseases in PwMS, the possible effect of this association on clinical and neuroradiological MS course and its impact on treatment choice.

Blood levels of brain-derived neurotrophic factor (BDNF) in people with multiple sclerosis (MS): A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis is an autoimmune demyelinating disease marked by the involvement of multiple pathophysiological pathways, including BDNF. BDNF (brain-derived neurotrophic factor) is one of the main neurotrophic factors in the adult brain. The amount of BDNF in the blood can be utilized as a surrogate for the central expression of this marker. Given contradicting reports, we set out to answer the question, "How do blood levels of BDNF differ in people with multiple sclerosis (PwMS) compared to controls?"

METHODS

We performed a thorough search in MEDLINE, EMBASE, Web of Science, and the Cochrane Library databases, resulting in 13 eligible investigations. Eleven studies compared BDNF in serum of PwMS versus healthy controls (HC), and two studies provided BDNF levels in the plasma of PwMs. R version 4.0.4 was used for meta-analysis and visualizations. Mean difference (MD) was used for the measurement of effect size.

RESULTS

The final analysis included thirteen studies with 689 patients with MS and 583 controls. The preliminary results indicated that MS patients had statistically significant lower levels of BDNF than controls: SMD -5.1992 (95% CI [-8.4488; -1.9496], p-value < 0.0001. Additionally, subgroup analysis revealed a statistically significant difference in serum and plasma levels (p-value=0.01). Performing univariate meta-regression, disease duration and the proportion of males had, respectively, a significant negative and positive correlation with BDNF levels.

CONCLUSION

Circulating levels of BDNF are decreased in MS. Future studies should investigate the role of BDNF as a biomarker of disease severity and/or progression for a personalized approach to MS.

Laminin as a Biomarker of Blood-Brain Barrier Disruption under Neuroinflammation: A Systematic Review

Laminin, a non-collagenous glycoprotein present in the brain extracellular matrix, helps to maintain blood–brain barrier (BBB) integrity and regulation. Neuroinflammation can compromise laminin structure and function, increasing BBB permeability. The aim of this paper is to determine if neuroinflammation-induced laminin functional changes may serve as a potential biomarker of alterations in the BBB. The 38 publications included evaluated neuroinflammation, BBB disruption, and laminin, and were assessed for quality and risk of bias (protocol registered in PROSPERO; CRD42020212547). We found that laminin may be a good indicator of BBB overall structural integrity, although changes in expression are dependent on the pathologic or experimental model used. In ischemic stroke, permanent vascular damage correlates with increased laminin expression (β and γ subunits), while transient damage correlates with reduced laminin expression (α subunits). Laminin was reduced in traumatic brain injury and cerebral hemorrhage studies but increased in multiple sclerosis and status epilepticus studies. Despite these observations, there is limited knowledge about the role played by different subunits or isoforms (such as 411 or 511) of laminin in maintaining structural architecture of the BBB under neuroinflammation. Further studies may clarify this aspect and the possibility of using laminin as a biomarker in different pathologies, which have alterations in BBB function in common.

Invited review: Unearthing the mechanisms of age-related neurodegenerative disease using Caenorhabditis elegans

As human life expectancy increases, neurodegenerative diseases present a growing public health threat, for which there are currently few effective treatments. There is an urgent need to understand the molecular and genetic underpinnings of these disorders so new therapeutic targets can be identified. Here we present the argument that the simple nematode worm Caenorhabditis elegans is a powerful tool to rapidly study neurodegenerative disorders due to their short lifespan and vast array of genetic tools, which can be combined with characterization of conserved neuronal processes and behavior orthologous to those disrupted in human disease. We review how pre-existing C. elegans models provide insight into human neurological disease as well as an overview of current tools available to study neurodegenerative diseases in the worm, with an emphasis on genetics and behavior. We also discuss open questions that C. elegans may be particularly well suited for in future studies and how worms will be a valuable preclinical model to better understand these devastating neurological disorders.

Update on Multiple Sclerosis Molecular Biomarkers to Monitor Treatment Effects

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system characterized by broad inter- and intraindividual heterogeneity. The relapse rate, disability progression, and lesion load assessed through MRI are used to detect disease activity and response to treatment. Although it is possible to standardize these characteristics in larger patient groups, so far, this has been difficult to achieve in individual patients. Easily detectable molecular biomarkers can be powerful tools, permitting a tailored therapy approach for MS patients. However, only a few molecular biomarkers have been routinely used in clinical practice as the validation process, and their transfer into clinical practice takes a long time. This review describes the characteristics of an ideal MS biomarker, the challenges of establishing new biomarkers, and promising molecular biomarkers from blood or CSF samples used to monitor MS treatment effects in clinical practice.

Evaluation of S100A12 and Apo-A1 plasma level potency in untreated new relapsing-remitting multiple sclerosis patients and their family members

Multiple sclerosis is an inflammatory disease of the spinal cord and brain. Receptor for advanced glycation end products and Apolipoprotein A1 (Apo-AI) have been recommended to have a pathogenic role in the neuroinflammatory disorder as multiple sclerosis. The purpose of this research was to measure the plasma levels of S100A12 and Apo-A1 in the first-degree family of relapsing–remitting multiple sclerosis (RRMS) patients. Plasma levels of S100A12 & Apo-A1 were evaluated via enzyme-linked immunosorbent assay in the thirty-five new cases of untreated patients with deterministic RRMS according to the McDonald criteria, twenty-four healthy controls, and twenty-six first-degree members of untreated RRMS patients (called them as high-risk group). The main findings of this study were as follows: the plasma level of S100A12 was significantly lower in the new cases of untreated RRMS (P ≤ 0.05; 0.045) and high-risk (P ≤ 0.05; 0.001) groups. Although the plasma protein level of Apo-A1 was reduced significantly in the high-risk group (P < 0.05, P = 0.003) as compared to the healthy control group, there was no significant difference in the untreated RRMS patients (P = 0.379). The plasma level of vitamin D3 in both RRMS patients and high-risk groups displayed significance reduction, although, there was no significant association between vitamin D and S100A12 & Apo-A1 levels. Given the role of S100A12 and Apo-A1 in the inflammatory process performed in the first-degree family members of the RRMS patients, which revealed a significant decrease in this group, we concluded that they can be considered as one of the contributing factors in the pathogenesis of MS, though more research is needed before assuming them as predictive biomarkers.

Role of JAK/STAT in the Neuroinflammation and its Association with Neurological Disorders

Background:

Innate immunity is mediated by a variety of cell types, including microglia, macrophages, and neutrophils, and serves as the immune system's first line of defense. There are numerous pathways involved in innate immunity, including the interferon (IFN) pathway, TRK pathway, mitogen-activated protein kinase (MAPK) pathway, Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, interleukin (IL) pathways, chemokine pathways (CCR5), GSK signaling, and Fas signaling.

Summary:

JAK/STAT is one of these important signaling pathways and this review focused on JAK/STAT signaling pathway only. The overactivation of microglia and astrocytes influences JAK/STAT's role in neuroinflammatory disease by initiating innate immunity, orchestrating adaptive immune mechanisms, and ultimately constraining inflammatory and immunological responses. The JAK/STAT signaling pathway is one of the critical factors that promotes neuroinflammation in neurodegenerative diseases.

Key message:

Given the importance of the JAK/STAT pathway in neurodegenerative disease, this review discussed the feasibility of targeting the JAK/STAT pathway as a neuroprotective therapy for neurodegenerative diseases in near future.

Therapeutic Effects of Physical Exercise and the Mesenchymal Stem Cell Secretome by Modulating Neuroinflammatory Response in Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative, demyelinating, and chronic inflammatory disease characterized by central nervous system (CNS) lesions that lead to high levels of disability and severe physical and cognitive disturbances. Conventional therapies are not enough to control the neuroinflammatory process in MS and are not able to inhibit ongoing damage to the CNS. Thus, the secretome of mesenchymal stem cells (MSC-S) has been postulated as a potential therapy that could mitigate symptoms and disease progression. We considered that its combination with physical exercise (EX) could induce superior effects and increase the MSC-S effectiveness in this condition. Recent studies have revealed that both EX and MSC-S share similar mechanisms of action that mitigate auto-reactive T cell infiltration, regulate the local inflammatory response, modulate the proinflammatory profile of glial cells, and reduce neuronal damage. Clinical and experimental studies have reported that these treatments in an isolated way also improve myelination, regeneration, promote the release of neurotrophic factors, and increase the recruitment of endogenous stem cells. Together, these effects reduce disease progression and improve patient functionality. Despite these results, the combination of these methods has not yet been studied in MS. In this review, we focus on molecular elements and cellular responses induced by these treatments in a separate way, showing their beneficial effects in the control of symptoms and disease progression in MS, as well as indicating their contribution in clinical fields. In addition, we propose the combined use of EX and MSC-S as a strategy to boost their reparative and immunomodulatory effects in this condition, combining their benefits on synaptogenesis, neurogenesis, remyelination, and neuroinflammatory response. The findings here reported are based on the scientific evidence and our professional experience that will bring significant progress to regenerative medicine to deal with this condition.

Neuropharmacological Effects of Quercetin: A Literature-Based Review

Quercetin (QUR) is a natural bioactive flavonoid that has been lately very studied for its beneficial properties in many pathologies. Its neuroprotective effects have been demonstrated in many in vitro studies, as well as in vivo animal experiments and human trials. QUR protects the organism against neurotoxic chemicals and also can prevent the evolution and development of neuronal injury and neurodegeneration. The present work aimed to summarize the literature about the neuroprotective effect of QUR using known database sources. Besides, this review focuses on the assessment of the potential utilization of QUR as a complementary or alternative medicine for preventing and treating neurodegenerative diseases. An up-to-date search was conducted in PubMed, Science Direct and Google Scholar for published work dealing with the neuroprotective effects of QUR against neurotoxic chemicals or in neuronal injury, and in the treatment of neurodegenerative diseases. Findings suggest that QUR possess neuropharmacological protective effects in neurodegenerative brain disorders such as Alzheimer’s disease, Amyloid β peptide, Parkinson’s disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis. In summary, this review emphasizes the neuroprotective effects of QUR and its advantages in being used in complementary medicine for the prevention and treatment o of different neurodegenerative diseases.

What do we know about the role of lncRNAs in multiple sclerosis?

Multiple sclerosis is a chronic, inflammatory and degenerative disease of the central nervous system of unknown aetiology although well-defined evidence supports an autoimmune pathogenesis. So far, the exact mechanisms leading to autoimmune diseases are still only partially understood. We know that genetic, epigenetic, molecular, and cellular factors resulting in pathogenic inflammatory responses are certainly involved. Long non-coding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides that play an important role in both innate and acquired immunity, so there is great interest in lncRNAs involved in autoimmune diseases. The research on multiple sclerosis has been enriched with many studies on the molecular role of lncRNAs in the pathogenesis of the disease and their potential application as diagnostic and prognostic biomarkers. In particular, many multiple sclerosis fields of research are based on the identification of lncRNAs as possible biomarkers able to predict the onset of the disease, its activity degree, its progression phase and the response to disease-modifying drugs. Last but not least, studies on lncRNAs can provide a new molecular target for new therapies, missing, so far, a cure for multiple sclerosis. While our knowledge on the role of lncRNA in multiple sclerosis has recently improved, further studies are required to better understand the specific role of lncRNAs in this neurological disease. In this review, we present the most recent studies on molecular characterization of lncRNAs in multiple sclerosis disorder discussing their clinical relevance as biomarkers for diagnosis and treatments.

S, MUREȘANU FD. The twisted role of natalizumab and rehabilitation in an aggressive form of multiple sclerosis: a case report

Multiple sclerosis is one of the main causes of neurological disability among young people, severely influencing life’s quality. Motor deficit is one of the most invalidating symptoms in multiple sclerosis. Motor involvement at onset, spinal demyelinating lesion distribution, highly active lesions, high frequency of relapses in the first 2 years after disease onset and post relapse residual disability with poor recovery, later age at onset and male gender represent unfavorable prognostic factors. Considering the significant role of prognostic factors in predicting the evolution of the disease, an induction treatment approach should always be considered. In this report we present the case of a middle-aged male patient presenting severe weakness and sensitive symptoms with a challenging therapeutic decision that had a favorable recovery after reconsidering the initial therapy. The recognition of aggressive forms of multiple sclerosis is mandatory in preventing further disability, improving the patient’s quality of life. Natalizumab is a monoclonal antibody used for the aggressive forms of multiple sclerosis, reducing the lymphocytes traffic through the blood brain barrier, with a great impact on relapses frequency and disease evolution. Keywords: aggressive multiple sclerosis, brain derived neurotrophic factor, natalizumab, rehabilitation,

B Cells in Multiple Sclerosis and Virus-Induced Neuroinflammation

Neuroinflammation can be defined as an inflammatory response within the central nervous system (CNS) mediated by a complex crosstalk between CNS-resident and infiltrating immune cells from the periphery. Triggers for neuroinflammation not only include pathogens, trauma and toxic metabolites, but also autoimmune diseases such as neuromyelitis optica spectrum disorders and multiple sclerosis (MS) where the inflammatory response is recognized as a disease-escalating factor. B cells are not considered as the first responders of neuroinflammation, yet they have recently gained focus as a key component involved in the disease pathogenesis of several neuroinflammatory disorders like MS. Traditionally, the prime focus of the role of B cells in any disease, including neuroinflammatory diseases, was their ability to produce antibodies. While that may indeed be an important contribution of B cells in mediating disease pathogenesis, several lines of recent evidence indicate that B cells are multifunctional players during an inflammatory response, including their ability to present antigens and produce an array of cytokines. Moreover, interaction between B cells and other cellular components of the immune system or nervous system can either promote or dampen neuroinflammation depending on the disease. Given that the interest in B cells in neuroinflammation is relatively new, the precise roles that they play in the pathophysiology and progression of different neuroinflammatory disorders have not yet been well-elucidated. Furthermore, the possibility that they might change their function during the course of neuroinflammation adds another level of complexity and the puzzle remains incomplete. Indeed, advancing our knowledge on the role of B cells in neuroinflammation would also allow us to tackle these disorders better. Here, we review the available literature to explore the relationship between autoimmune and infectious neuroinflammation with a focus on the involvement of B cells in MS and viral infections of the CNS.

Mechanisms of M2 Macrophage-Derived Exosomal Long Non-coding RNA PVT1 in Regulating Th17 Cell Response in Experimental Autoimmune Encephalomyelitisa

Long non-coding RNA (lncRNA) is pivotal for multiple sclerosis (MS), but the potential mechanism of lncRNA PVT1 in MS animal model, experimental autoimmune encephalomyelitis (EAE) still remains unclear. In this study, macrophages were firstly isolated and induced to polarize into M2 macrophages. M2 macrophage-derived exosomes (M2-exos) were extracted and identified, and EAE mouse model was established and treated with M2-exos. The effect of M2-exos on EAE mice was evaluated by clinical scores. The proportion of Treg and Th17 cells in spinal cord cells and splenocytes, and levels of inflammatory factors were measured. The targeting relationships among PVT1, miR-21-5p, and SOCS5 were verified. The expression of JAKs/STAT3 pathway-related proteins was measured. After M2-exo treatment, the clinical score of EAE mice decreased, and demyelination and inflammatory infiltration improved; Th17 cells decreased, Treg cells increased, and the levels of inflammatory factors decreased significantly. SOCS5 and PVT1 were downregulated and miR-21-5p was upregulated in EAE mice. PVT1 could sponge miR-21-5p to regulate SOCS5. SOCS5 alleviated EAE symptoms by repressing the JAKs/STAT3 pathway. Together, M2-exos-carried lncRNA PVT1 sponged miR-21-5p to upregulate SOCS5 and inactivate the JAKs/STAT3 pathway, thus reducing inflammation and protecting EAE mice. This study may offer novel treatments for MS.

Neuroprotective modulation of microglia effector functions following priming with interleukin 4 and 13: current limitations in understanding their mode-of-action

In recent years the long-standing theory of microglia's properties for dual polarization towards a pro- or anti-inflammatory phenotype has been deeply challenged. Furthermore, the elucidation of microglia ontogenesis exposed intrinsic differences between microglia and peripheral myeloid cells, thereby further underscoring the need to re-evaluate microglia-specific activation behavior, especially within an inflamed central nervous system (CNS) environment. This review critically summarizes recent literature on the in vitro and in vivo response of murine microglia to the immune-modulatory cytokines interleukin 4 (IL4) and interleukin 13 (IL13), i.e. those driving the so-called anti-inflammatory phenotype. Here we highlight several pivotal factors that may influence experimental outcome and/or interpretation of in vitro and in vivo studies evaluating microglia's phenotypical and functional properties upon IL4/IL13 treatment. Finally, the current therapeutic relevance of IL4/IL13-induced microglia activation in both acute and chronic CNS disorders is discussed.

Inflammation in Neurological Disorders: The Thin Boundary Between Brain and Periphery

Significance: Accumulating evidence suggests that inflammation is a major contributor in the pathogenesis of several highly prevalent, but also rare, neurological diseases. In particular, the neurodegenerative processes of Alzheimer's disease (AD), vascular dementia (VAD), Parkinson's disease (PD), and multiple sclerosis (MS) are fueled by neuroinflammation, which, in turn, is accompanied by a parallel systemic immune dysregulation. This cross-talk between periphery and the brain becomes substantial when the blood-brain barrier loses its integrity, as often occurs in the course of these diseases. It has been hypothesized that the perpetual bidirectional flux of inflammatory mediators is not a mere "static" collateral effect of the neurodegeneration, but represents a proactive phenomenon sparking and driving the neuropathological processes. However, the upstream/downstream relationship between inflammatory events and neurological pathology is still unclear. Recent Advances: Solid recent evidence clearly suggests that metabolic factors, systemic infections, Microbiota dysbiosis, and oxidative stress are implicated, although to a different extent, in the development in brain diseases. Critical Issues: Here, we reviewed the most solid published evidence supporting the implication of the axis systemic inflammation-neuroinflammation-neurodegeneration in the pathogenesis of AD, VAD, PD, and MS, highlighting the possible cause of the putative downstream component of the axis. Future Directions: Reaching a definitive clinical/epidemiological appreciation of the etiopathogenic significance of the connection between peripheral and brain inflammation in neurologic disorders is pivotal since it could open novel therapeutic avenues for these diseases.

Maternal micro-chimeric cells in the multiple sclerosis brain

Maternal microchimeric cells (MMC) pass across the placenta from a mother to her baby during pregnancy. MMC have been identified in healthy adults, but have been reported to be more frequent and at a higher concentration in individuals with autoimmune diseases. MMC in brain tissue from individuals with autoimmune neurological disease has never previously been explored. The present study aims to identify and quantify MMC in adult human brain from control and multiple sclerosis (MS) affected individuals using fluorescent in situ hybridization (FISH) with a probe for the X and Y chromosomes. Post mortem brain tissue from 6 male MS cases and 6 male control cases were examined. Female cells presumed to be MMC were identified in 5/6 MS cases and 6/6 control cases. Cell specific labeling identified female cells of neuronal and immune phenotype in both control and active MS lesion tissue. This study shows that female cells presumed to be MMC are a common phenomenon in adult human brain where they appear to have embedded into brain tissue with the ability to express tissue specific markers.

Oligodendrocyte dysfunction and regeneration failure: A novel hypothesis of delayed encephalopathy after carbon monoxide poisoning

Carbon monoxide (CO) poisoning usually causes brain lesions and delayed encephalopathy, also known as delayed neurological sequelae (DNS). Demyelination of white matter (WM) is one of the most common sites of abnormalities in patients with DNS, but its mechanisms remain unclear. Oligodendrocytes (OLs) are myelinated cells that ensure the rapid conduction of neuronal axon signals and provide the nutritional factors necessary for maintaining nerve integrity in the central nervous system (CNS). OLs readily regenerate and replace damaged myelin membranes around axons in the adult mammalian CNS following demyelination. The ability to regenerate OLs depends on the availability of precursor cells (OPCs) in the CNS of adults. Multiple injury-related signals can induce OPC expansion followed by OL differentiation, axonal contact and myelin regeneration (remyelination). Therefore, OL dysfunction and regeneration failure in the deep WM of the brain are the key pathophysiological mechanisms leading to delayed brain injury after CO poisoning. CO-induced toxicity may interfere with OL function and render OPCs unable to regenerate OLs through some unclear mechanisms, leading to progressive demyelinating damage and resulting in DNS. In the future, combination therapies to reduce OL damage and promote OPC differentiation and remyelination may be important for the prevention and treatmentof DNS after CO poisoning.

Stem Cell-Derived Exosomes as Nanotherapeutics for Autoimmune and Neurodegenerative Disorders

To dissect therapeutic mechanisms of transplanted stem cells and develop exosome-based nanotherapeutics in treating autoimmune and neurodegenerative diseases, we assessed the effect of exosomes secreted from human mesenchymal stem cells (MSCs) in treating multiple sclerosis using an experimental autoimmune encephalomyelitis (EAE) mouse model. We found that intravenous administration of exosomes produced by MSCs stimulated by IFNγ (IFNγ-Exo) (i) reduced the mean clinical score of EAE mice compared to PBS control, (ii) reduced demyelination, (iii) decreased neuroinflammation, and (iv) upregulated the number of CD4+CD25+FOXP3+ regulatory T cells (Tregs) within the spinal cords of EAE mice. Co-culture of IFNγ-Exo with activated peripheral blood mononuclear cells (PBMCs) cells in vitro reduced PBMC proliferation and levels of pro-inflammatory Th1 and Th17 cytokines including IL-6, IL-12p70, IL-17AF, and IL-22 yet increased levels of immunosuppressive cytokine indoleamine 2,3-dioxygenase. IFNγ-Exo could also induce Tregs in vitro in a murine splenocyte culture, likely mediated by a third-party accessory cell type. Further, IFNγ-Exo characterization by deep RNA sequencing suggested that IFNγ-Exo contains anti-inflammatory RNAs, where their inactivation partially hindered the exosomes potential to induce Tregs. Furthermore, we found that IFNγ-Exo harbors multiple anti-inflammatory and neuroprotective proteins. These results not only shed light on stem cell therapeutic mechanisms but also provide evidence that MSC-derived exosomes can potentially serve as cell-free therapies in creating a tolerogenic immune response to treat autoimmune and central nervous system disorders.

Lipoxin A4 Regulates Lipopolysaccharide-Induced BV2 Microglial Activation and Differentiation via the Notch Signaling Pathway

Inflammatory responses contribute to the pathogenesis of various neurological diseases, and microglia plays an important role in the process. Activated microglia can differentiate into the pro-inflammatory, tissue-damaging M1 phenotype or the anti-inflammatory, tissue-repairing M2 phenotype. Regulating microglia differentiation, hence limiting a harmful response, might help improve the prognosis of inflammation-related nervous system diseases. The present study aimed 1. to observe the anti-inflammatory effect of lipoxin A4 (LXA4) on the inflammatory response associated to lipopolysaccharide (LPS)-induced microglia activation, 2. to clarify that LXA4 modulates the activation and differentiation of microglia induced by LPS stimulation, 3. to determine whether LXA4 regulates the activation and differentiation of microglia through the Notch signaling pathway, 4. to provide a foundation for the use of LXA4 for the treatment of inflammatory related neurological diseases. To construct a model of cellular inflammation, immortalized murine BV2 microglia cells were provided 200 ng/ml LPS. To measure the mRNA and protein levels of inflammatory factors (interleukin [IL]-1β, IL-10, and tumor necrosis factor [TNF]-α) and M1 and M2 microglia markers (inducible nitric oxide synthase [iNOS], cluster of differentiation [CD]32, arginase [Arg]1, and CD206), we performed quantitative reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA), immunofluorescence, or flow cytometry. To determine the mRNA and protein levels of Notch signaling components (Notch1, Hes1, and Hes5), we performed qRT-PCR and western blot. LXA4 inhibits the expression of Notch1 and Hes1 associated with M1 type microglial differentiation and decreases the M1 type microglia marker iNOS and related inflammatory factors IL-1β and TNF-α. Moreover, LXA4 upregulates the expression of the M2-associated Hes5, as well as the expression of the M2 microglia marker Arg1 and the associated inflammatory factor IL-10. These effects are blocked by the administration of the γ-secretase inhibitor DAPT, a specific blocker of the Notch signaling pathway. LXA4 inhibits the microglia activation induced by LPS and the differentiation into M1 type with pro-inflammatory effect, while promoting the differentiation to M2 type with anti-inflammatory effect. LXA4 downregulates the inflammatory mediators IL-1β, TNF-α, and iNOS, while upregulating the anti-inflammatory mediator IL-10, which acts through the Notch signaling pathway.

Regulatory B and T lymphocytes in multiple sclerosis: friends or foes?

Current clinical experience with immunomodulatory agents and monoclonal antibodies in principle has established the benefit of depleting lymphocytic populations in relapsing–remitting multiple sclerosis (RRMS). B and T cells may exert multiple pro-inflammatory actions, but also possess regulatory functions making their role in RRMS pathogenesis much more complex. There is no clear correlation of Tregs and Bregs with clinical features of the disease. Herein, we discuss the emerging data on regulatory T and B cell subset distributions in MS and their roles in the pathophysiology of MS and its murine model, experimental autoimmune encephalomyelitis (EAE). In addition, we summarize the immunomodulatory properties of certain MS therapeutic agents through their effect on such regulatory cell subsets and their relevance to clinical outcomes.

BDNF rs6265 polymorphism methylation in Multiple Sclerosis: A possible marker of disease progression

INTRODUCTION

Brain-Derived Neurotrophic Factor (BDNF) and its most common polymorphism Val66Met are known to have a role in Multiple Sclerosis (MS) pathogenesis. Evidence is accumulating that there is an involvement of DNA methylation in the regulation of BDNF expression. The aim of this study was to assess in blood samples of MS patients the correlation between the methylation status of the CpG site near BDNF-Val66Met polymorphism and the severity of the disease.

METHODS

We recruited 209 MS patients that were genotyped for the BDNF Val66Met polymorphism. For each patient we quantitatively measured the methylation level of cytosine included in the exonic CpG site that can be created or abolished by the Val66Met BDNF polymorphism. Furthermore, we analyzed the clinical history of each patient and determined the time elapsed since the onset of the disease and an EDSS score of 6.0.

RESULTS

The genetic analysis identified 122 (58.4%) subjects carrying the Val/Val genotype, 81 (38.8%) with Val/Met genotype, and 6 (2.8%) carrying the Met/Met genotype. When the endpoint of an EDSS score of 6 was taken into account by means of a survival analysis, 52 failures (i.e., reaching an EDSS score of 6) were reported. When the sample was stratified according to the percentage of the BDNF methylation, subjects falling below the median (median methylation = 81%) were at higher risk of failure (IRD = 0.016; 95%CI = 0.0050-0.0279; p = 0.004).

CONCLUSIONS

In patients with a high disease progression the hypomethylation of the BDNF gene could increase the secretion of the protective neurotrophin, so epigenetic modifications could be the organism response to limit a brain functional reserve loss. Our study suggests that the percentage of methylation of the BDNF gene could be used as a prognostic factor for disease progression toward a high disability in MS patient.

Multiple Immune-Inflammatory and Oxidative and Nitrosative Stress Pathways Explain the Frequent Presence of Depression in Multiple Sclerosis

Patients with a diagnosis of multiple sclerosis (MS) or major depressive disorder (MDD) share a wide array of biological abnormalities which are increasingly considered to play a contributory role in the pathogenesis and pathophysiology of both illnesses. Shared abnormalities include peripheral inflammation, neuroinflammation, chronic oxidative and nitrosative stress, mitochondrial dysfunction, gut dysbiosis, increased intestinal barrier permeability with bacterial translocation into the systemic circulation, neuroendocrine abnormalities and microglial pathology. Patients with MS and MDD also display a wide range of neuroimaging abnormalities and patients with MS who display symptoms of depression present with different neuroimaging profiles compared with MS patients who are depression-free. The precise details of such pathology are markedly different however. The recruitment of activated encephalitogenic Th17 T cells and subsequent bidirectional interaction leading to classically activated microglia is now considered to lie at the core of MS-specific pathology. The presence of activated microglia is common to both illnesses although the pattern of such action throughout the brain appears to be different. Upregulation of miRNAs also appears to be involved in microglial neurotoxicity and indeed T cell pathology in MS but does not appear to play a major role in MDD. It is suggested that the antidepressant lofepramine, and in particular its active metabolite desipramine, may be beneficial not only for depressive symptomatology but also for the neurological symptoms of MS. One clinical trial has been carried out thus far with, in particular, promising MRI findings.

Inhibition of Inflammation, Suppression of Matrix Metalloproteinases, Induction of Neurogenesis, and Antioxidant Property Make Bryostatin-1 a Therapeutic Choice for Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease characterized by inflammation and myelin damage. Pro-inflammatory cytokines, oxidative stress, high level of matrix metalloproteinases (MMPs) activity and blood-brain barrier (BBB) damage, immune-mediated destruction of myelin and neuron loss are involved in the pathogenesis of MS. The currently approved treatments for MS include injectable drugs (interferon-β and glatiramer acetate), oral drugs (fingolimod), and monoclonal antibodies (natalizumab). The mentioned therapeutic choices are mostly focused on the inhibition of inflammation. Therefore, the search for a multi-target therapeutic choice remains unchallenged. It seems that a drug with anti-inflammatory, oxidative stress inhibitory, reduction of MMPs activity, and neurogenesis stimulatory properties may be effective for treatment of MS. In this regard, Bryostatin-1 as a macrolide and marine natural product has been selected as a therapeutic choice. Studies indicate that Bryostatin-1 has anti-inflammatory and antioxidant properties and decreases MMPs level and BBB damage. Furthermore, Bryostatin-1 has a neuroprotective effect and promotes neurogenesis and differentiation of oligodendrocyte progenitor stem cells as a critical step for remyelination/myelogenesis. Based on these properties, we hypothesized here that Bryostatin-1 is an effective treatment in MS.

Effect of acetylcholinesterase inhibitors donepezil and rivastigmine on the activity and expression of cyclooxygenases in a model of the inflammatory action of fluoride on macrophages obtained from THP-1 monocytes

Inflammation is an important factor in the development of many diseases of the central nervous system, including Alzheimer's disease and other types of dementia. ‪Given that acetylcholinesterase inhibitors are also currently believed to have anti-inflammatory properties, the purpose of this study was to investigate the effect of acetylcholinesterase inhibitors (rivastigmine, donepezil) on cyclooxygenase activity and expression using the proinflammatory action of fluoride (F^-) on cultured macrophages obtained from THP-1 monocytes. COX-1 and COX-2 activity was determined through measurement of the products of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in cell culture supernatants. Expression of COX-1 and COX-2 proteins was examined immunocytochemically, and mRNA expression was determined by qRT PCR. ‪‪ Our study confirmed the inhibitory effects of donepezil and rivastigmine on the production of PGE2, TXB2, COX-1 and COX-2 mRNA and protein expression in macrophages. We also demonstrated that the pro-inflammatory effect of fluoride may be reduced by the use of both drugs. The additive effect of these drugs cannot be ruled out, and effects other than those observed in the use of one drug should also be taken into account.

Friend or foe: the dichotomous impact of T cells on neuro-de/re-generation during aging

The interaction between T cells and the central nervous system (CNS) in homeostasis and injury has been recognized being both pathogenic (CD4⁺ T-helper 1 - Th1, Th17 and γδT) and ameliorative (Th2 and regulatory T cells - Tregs). However, in-depth studies aimed to elucidate the precise in the aged microenvironment and the dichotomous role of Tregs have just begun and many aspects remain unclear. This is due, not only to a mutual dependency and reciprocal causation of alterations and diseases between the nervous and T cell immune systems, but also to an inconsistent aging of the two systems, which dynamically changes with CNS injury/recovery and/or aging process. Cellular immune system aging, particularly immunosenescence and T cell aging initiated by thymic involution - sources of chronic inflammation in the elderly (termed inflammaging), potentially induces an acceleration of brain aging and memory loss. In turn, aging of the brain via neuro-endocrine-immune network drives total body systemic aging, including that of the immune system. Therefore, immunotherapeutics including vaccination and “protective autoimmunity” provide promising means to rejuvenate neuro-inflammatory disorders and repair CNS acute injury and chronic neuro-degeneration. We review the current understanding and recent discoveries linking the aging immune system with CNS injury and neuro-degeneration. Additionally, we discuss potential recovery and rejuvenation strategies, focusing on targeting the aging T cell immune system in an effort to alleviate acute brain injury and chronic neuro-degeneration during aging, via the “thymus-inflammaging-neurodegeneration axis”.

Spatiotemporal resolution of spinal meningeal and parenchymal inflammation during experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) induced by active immunization of C57BL/6 mice with peptide from myelin oligodendrocyte protein (MOG_35-55), is a neuroinflammatory, demyelinating disease widely recognized as an animal model of multiple sclerosis (MS). Typically, EAE presents with an ascending course of paralysis, and inflammation that is predominantly localized to the spinal cord. Recent studies have further indicated that inflammation - in both MS and EAE - might initiate within the meninges and propagate from there to the underlying parenchyma. However, the patterns of inflammation within the respective meningeal and parenchymal compartments along the length of the spinal cord, and the progression with which these patterns develop during EAE, have yet to be detailed. Such analysis could hold key to identifying factors critical for spreading, as well as constraining, inflammation along the neuraxis. To address this issue, high-resolution 3-dimensional (3D) confocal microscopy was performed to visualize, in detail, the sequence of leukocyte infiltration at distinct regions of the spinal cord. High quality virtual slide scanning for imaging the entire spinal cord using epifluorescence was further conducted to highlight the directionality and relative degree of inflammation. Meningeal inflammation was found to precede parenchymal inflammation at all levels of the spinal cord, but did not develop equally or simultaneously throughout the subarachnoid space (SAS) of the meninges. Instead, meningeal inflammation was initially most obvious in the caudal SAS, from which it progressed to the immediate underlying parenchyma, paralleling the first signs of clinical disease in the tail and hind limbs. Meningeal inflammation could then be seen to extend in the caudal-to-rostral direction, followed by a similar, but delayed, trajectory of parenchymal inflammation. To additionally determine whether the course of ascending paralysis and leukocyte infiltration during EAE is reflected in differences in inflammatory gene expression by meningeal and parenchymal microvessels along the spinal cord, laser capture microdissection (LCM) coupled with gene expression profiling was performed. Expression profiles varied between these respective vessel populations at both the cervical and caudal levels of the spinal cord during disease progression, and within each vessel population at different levels of the cord at a given time during disease. These results reinforce a significant role for the meninges in the development and propagation of central nervous system inflammation associated with MS and EAE.

Impact of aging immune system on neurodegeneration and potential immunotherapies

The interaction between the nervous and immune systems during aging is an area of avid interest, but many aspects remain unclear. This is due, not only to the complexity of the aging process, but also to a mutual dependency and reciprocal causation of alterations and diseases between both the nervous and immune systems. Aging of the brain drives whole body systemic aging, including aging-related changes of the immune system. In turn, the immune system aging, particularly immunosenescence and T cell aging initiated by thymic involution that are sources of chronic inflammation in the elderly (termed inflammaging), potentially induces brain aging and memory loss in a reciprocal manner. Therefore, immunotherapeutics including modulation of inflammation, vaccination, cellular immune therapies and "protective autoimmunity" provide promising approaches to rejuvenate neuroinflammatory disorders and repair brain injury. In this review, we summarize recent discoveries linking the aging immune system with the development of neurodegeneration. Additionally, we discuss potential rejuvenation strategies, focusing aimed at targeting the aging immune system in an effort to prevent acute brain injury and chronic neurodegeneration during aging.

Exploring the potential of natural and synthetic neuroprotective steroids against neurodegenerative disorders: A literature review

Neurodegeneration is a complex process, which leads to progressive brain damage due to loss of neurons. Despite exhaustive research, the cause of neuronal loss in various degenerative disorders is not entirely understood. Neuroprotective steroids constitute an important line of attack, which could play a major role against the common mechanisms associated with various neurodegenerative disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Natural endogenous steroids induce the neuroprotection by protecting the nerve cells from neuronal injury through multiple mechanisms, therefore the structural modifications of the endogenous steroids could be helpful in the generation of new therapeutically useful neuroprotective agents. The review article will keep the readers apprised of the detailed description of natural as well as synthetic neuroprotective steroids from the medicinal chemistry point of view, which would be helpful in drug discovery efforts aimed toward neurodegenerative diseases.

Primary Progressive Multiple Sclerosis: Putting Together the Puzzle

The focus of multiple sclerosis research has recently turned to the relatively rare and clearly more challenging condition of primary progressive multiple sclerosis (PPMS). Many risk factors such as genetic susceptibility, age, and Epstein–Barr virus (EBV) infection may interdepend on various levels, causing a complex pathophysiological cascade. Variable pathological mechanisms drive disease progression, including inflammation-associated axonal loss, continuous activation of central nervous system resident cells, such as astrocytes and microglia as well as mitochondrial dysfunction and iron accumulation. Histological studies revealed diffuse infiltration of the gray and white matter as well as of the meninges with inflammatory cells such as B-, T-, natural killer, and plasma cells. While numerous anti-inflammatory agents effective in relapsing remitting multiple sclerosis basically failed in treatment of PPMS, the B-cell-depleting monoclonal antibody ocrelizumab recently broke the dogma that PPMS cannot be treated by an anti-inflammatory approach by demonstrating efficacy in a phase 3 PPMS trial. Other treatments aiming at enhancing remyelination (MD1003) as well as EBV-directed treatment strategies may be promising agents on the horizon. In this article, we aim to summarize new advances in the understanding of risk factors, pathophysiology, and treatment of PPMS. Moreover, we introduce a novel concept to understand the nature of the disease and possible treatment strategies in the near future.

Absence of system xc- on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

BACKGROUND

Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x_c^- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration.

METHODS

Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x_c^-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT^-/-) mice and irradiated mice reconstituted in xCT^-/- bone marrow (BM), to their proper wild type (xCT^+/+) controls.

RESULTS

xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT^+/+ mice, xCT^-/- mice were equally susceptible to EAE, whereas mice transplanted with xCT^-/- BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected.

CONCLUSIONS

Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x_c^- on immune cells invading the CNS participates to EAE. Since a total loss of system x_c^- had no net beneficial effects, these results have important implications for targeting system x_c^- for treatment of MS.

Bioactive effects of quercetin in the central nervous system: Focusing on the mechanisms of actions

Quercetin, a ubiquitous flavonoid that is widely distributed in plants is classified as a cognitive enhancer in traditional and oriental medicine. The protective effects of quercetin for the treatment of neurodegenerative disorders and cerebrovascular diseases have been demonstrated in both in vitro and in vivo studies. The free radical scavenging activity of quercetin has been well-documented, wherein quercetin has been observed to exhibit protective effects against oxidative stress mediated neuronal damage by modulating the expression of NRF-2 dependent antioxidant responsive elements, and attenuation of neuroinflammation by suppressing NF-κB signal transducer and activator of transcription-1 (STAT-1). Several in vitro and in vivo studies have also shown that quercetin destabilizes and enhances the clearance of abnormal protein such as beta- amyloid peptide and hyperphosphorlyated tau, the key pathological hallmarks of Alzheimer's disease. Quercetin enhances neurogenesis and neuronal longevity by modulating a broad number of kinase signaling cascades such as phophoinositide 3- kinase (P13-kinase), AKT/PKB tyrosine kinase and Protein kinase C (PKC). Quercetin has also been well reported for its ability to reverse cognitive impairment and memory enhancement during aging. The current review focuses on summarizing the recent findings on the neuroprotective effect of quercetin, its mechanism of action and its possible roles in the prevention of neurological disorders.

Precision Medicine in Multiple Sclerosis: Future of PET Imaging of Inflammation and Reactive Astrocytes

Non-invasive molecular imaging techniques can enhance diagnosis to achieve successful treatment, as well as reveal underlying pathogenic mechanisms in disorders such as multiple sclerosis (MS). The cooperation of advanced multimodal imaging techniques and increased knowledge of the MS disease mechanism allows both monitoring of neuronal network and therapeutic outcome as well as the tools to discover novel therapeutic targets. Diverse imaging modalities provide reliable diagnostic and prognostic platforms to better achieve precision medicine. Traditionally, magnetic resonance imaging (MRI) has been considered the golden standard in MS research and diagnosis. However, positron emission tomography (PET) imaging can provide functional information of molecular biology in detail even prior to anatomic changes, allowing close follow up of disease progression and treatment response. The recent findings support three major neuroinflammation components in MS: astrogliosis, cytokine elevation, and significant changes in specific proteins, which offer a great variety of specific targets for imaging purposes. Regardless of the fact that imaging of astrocyte function is still a young field and in need for development of suitable imaging ligands, recent studies have shown that inflammation and astrocyte activation are related to progression of MS. MS is a complex disease, which requires understanding of disease mechanisms for successful treatment. PET is a precise non-invasive imaging method for biochemical functions and has potential to enhance early and accurate diagnosis for precision therapy of MS. In this review we focus on modulation of different receptor systems and inflammatory aspect of MS, especially on activation of glial cells, and summarize the recent findings of PET imaging in MS and present the most potent targets for new biomarkers with the main focus on experimental MS research.