Progressive multiple sclerosis: from pathophysiology to therapeutic strategies

Sanguinarine modulates microglial function via PPARγ activation and protects against CNS demyelination

Microglia aggregate in regions of active inflammation and demyelination in the CNS of multiple sclerosis (MS) patients and are considered pivotal in the disease process. Targeting microglia is a promising therapeutic approach for myelin repair. Previously, we identified two candidates for microglial modulation and remyelination using a Connectivity Map (CMAP)-based screening strategy. Interestingly, with results that overlapped, sanguinarine (SAN) emerged as a potential drug candidate to modulate microglial polarization and promote remyelination. In the current study, we demonstrate the efficacy of SAN in mitigating the MS-like experimental autoimmune encephalomyelitis (EAE) in a dose-dependent manner. Meanwhile, prophylactic administration of a medium dose (2.5 mg/kg) significantly reduces disease incidence and ameliorates clinical signs in EAE mice. At the cellular level, SAN reduces the accumulation of microglia in the spinal cord. Morphological analyses and immunophenotyping reveal a less activated state of microglia following SAN administration, supported by decreased inflammatory cytokine production in the spinal cord. Mechanistically, SAN skews primary microglia towards an immunoregulatory state and mitigates proinflammatory response through PPARγ activation. This creates a favorable milieu for the differentiation of oligodendrocyte progenitor cells (OPCs) when OPCs are incubated with conditioned medium from SAN-treated microglia. We further extend our investigation into the cuprizone-induced demyelinating model, confirming that SAN treatment upregulates oligodendrocyte lineage genes and increases myelin content, further suggesting its pro-myelination effect. In conclusion, our data propose SAN as a promising candidate adding to the preclinical therapeutic arsenal for regulating microglial function and promoting myelin repair in CNS demyelinating diseases such as MS.

Mitochondrial and metabolic dysfunction of peripheral immune cells in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disorder characterized by the infiltration of inflammatory cells and demyelination of nerves. Mitochondrial dysfunction has been implicated in the pathogenesis of MS, as studies have shown abnormalities in mitochondrial activities, metabolism, mitochondrial DNA (mtDNA) levels, and mitochondrial morphology in immune cells of individuals with MS. The presence of mitochondrial dysfunctions in immune cells contributes to immunological dysregulation and neurodegeneration in MS. This review provided a comprehensive overview of mitochondrial dysfunction in immune cells associated with MS, focusing on the potential consequences of mitochondrial metabolic reprogramming on immune function. Current challenges and future directions in the field of immune-metabolic MS and its potential as a therapeutic target were also discussed.

The Contribution of Microglia and Brain-Infiltrating Macrophages to the Pathogenesis of Neuroinflammatory and Neurodegenerative Diseases during TMEV Infection of the Central Nervous System

The infection of the central nervous system (CNS) with neurotropic viruses induces neuroinflammation and is associated with the development of neuroinflammatory and neurodegenerative diseases, including multiple sclerosis and epilepsy. The activation of the innate and adaptive immune response, including microglial, macrophages, and T and B cells, while required for efficient viral control within the CNS, is also associated with neuropathology. Under healthy conditions, resident microglia play a pivotal role in maintaining CNS homeostasis. However, during pathological events, such as CNS viral infection, microglia become reactive, and immune cells from the periphery infiltrate into the brain, disrupting CNS homeostasis and contributing to disease development. Theiler's murine encephalomyelitis virus (TMEV), a neurotropic picornavirus, is used in two distinct mouse models: TMEV-induced demyelination disease (TMEV-IDD) and TMEV-induced seizures, representing mouse models of multiple sclerosis and epilepsy, respectively. These murine models have contributed substantially to our understanding of the pathophysiology of MS and seizures/epilepsy following viral infection, serving as critical tools for identifying pharmacological targetable pathways to modulate disease development. This review aims to discuss the host-pathogen interaction during a neurotropic picornavirus infection and to shed light on our current understanding of the multifaceted roles played by microglia and macrophages in the context of these two complexes viral-induced disease.

Mechanisms Governing Oligodendrocyte Viability in Multiple Sclerosis and Its Animal Models

Multiple sclerosis (MS) is a chronic autoimmune inflammatory demyelinating disease of the central nervous system (CNS), which is triggered by an autoimmune assault targeting oligodendrocytes and myelin. Recent research indicates that the demise of oligodendrocytes due to an autoimmune attack contributes significantly to the pathogenesis of MS and its animal model experimental autoimmune encephalomyelitis (EAE). A key challenge in MS research lies in comprehending the mechanisms governing oligodendrocyte viability and devising therapeutic approaches to enhance oligodendrocyte survival. Here, we provide an overview of recent findings that highlight the contributions of oligodendrocyte death to the development of MS and EAE and summarize the current literature on the mechanisms governing oligodendrocyte viability in these diseases.

Myeloid cell-associated aromatic amino acid metabolism facilitates CNS myelin regeneration

Regulation of myeloid cell activity is critical for successful myelin regeneration (remyelination) in demyelinating diseases, such as multiple sclerosis (MS). Here, we show aromatic alpha-keto acids (AKAs) generated from the amino acid oxidase, interleukin-4 induced 1 (IL4I1), promote efficient remyelination in mouse models of MS. During remyelination, myeloid cells upregulated the expression of IL4I1. Conditionally knocking out IL4I1 in myeloid cells impaired remyelination efficiency. Mice lacking IL4I1 expression exhibited a reduction in the AKAs, phenylpyruvate, indole-3-pyruvate, and 4-hydroxyphenylpyruvate, in remyelinating lesions. Decreased AKA levels were also observed in people with MS, particularly in the progressive phase when remyelination is impaired. Oral administration of AKAs modulated myeloid cell-associated inflammation, promoted oligodendrocyte maturation, and enhanced remyelination in mice with focal demyelinated lesions. Transcriptomic analysis revealed AKA treatment induced a shift in metabolic pathways in myeloid cells and upregulated aryl hydrocarbon receptor activity in lesions. Our results suggest myeloid cell-associated aromatic amino acid metabolism via IL4I1 produces AKAs in demyelinated lesions to enable efficient remyelination. Increasing AKA levels or targeting related pathways may serve as a strategy to facilitate the regeneration of myelin in inflammatory demyelinating conditions.

Microglia and Multiple Sclerosis

Multiple sclerosis (MS) is a devastating autoimmune disease that leads to profound disability. This disability arises from the stochastic, regional loss of myelin-the insulating sheath surrounding neurons-in the central nervous system (CNS). The demyelinated regions are dominated by the brain's resident macrophages: microglia. Microglia perform a variety of functions in MS and are thought to initiate and perpetuate demyelination through their interactions with peripheral immune cells that traffic into the brain. However, microglia are also likely essential for recruiting and promoting the differentiation of cells that can restore lost myelin in a process known as remyelination. Given these seemingly opposing functions, an overarching beneficial or detrimental role is yet to be ascribed to these immune cells. In this chapter, we will discuss microglia dynamics throughout the MS disease course and probe the apparent dichotomy of microglia as the drivers of both demyelination and remyelination.

How Early Is Early Multiple Sclerosis?

The development and further optimization of the diagnostic criteria for multiple sclerosis (MS) emphasize the establishment of an early and accurate diagnosis. So far, numerous studies have revealed the significance of early treatment administration for MS and its association with slower disease progression and better late outcomes of the disease with regards to disability accumulation. However, according to current research results, both neuroinflammatory and neurodegenerative processes may exist prior to symptom initiation. Despite the fact that a significant proportion of individuals with radiologically isolated syndrome (RIS) progress to MS, currently, there is no available treatment approved for RIS. Therefore, our idea of "early treatment administration" might be already late in some cases. In order to detect the individuals who will progress to MS, we need accurate biomarkers. In this review, we present notable research results regarding the underlying pathology of MS, as well as several potentially useful laboratory and neuroimaging biomarkers for the identification of high-risk individuals with RIS for developing MS. This review aims to raise clinicians' awareness regarding "subclinical" MS, enrich their understanding of MS pathology, and familiarize them with several potential biomarkers that are currently under investigation and might be used in clinical practice in the future for the identification of individuals with RIS at high risk for conversion to definite MS.

Novel liposomal glatiramer acetate: Preparation and immunomodulatory evaluation in murine model of multiple sclerosis

The frequent administration rate required for Glatiramer acetate (GA), a first-line therapy for Multiple sclerosis (MS), poses patient compliance issues. Only a small portion of the subcutaneously administered GA is available for phagocytosis by macrophages, as most of it is hydrolyzed at its administration site or excreted renally. To unravel these hurdles, we have prepared liposomal formulations of GA through thin film-hydration method plus extrusion. The clinical and histopathological efficacy of GA-loaded liposomes were assessed in prophylactic and therapeutic manners on murine model of MS (experimental autoimmune encephalomyelitis (EAE)). The selected GA liposomal formulation showed favorable size (275 nm on average), high loading efficiency, and high macrophage localization. Moreover, administration of GA-liposomes in mice robustly suppressed the inflammatory responses and decreased the inflammatory and demyelinated lesion regions in CNS compared to the free GA with subsequent reduction of the EAE clinical score. Our study indicated that liposomal GA could be served as a reliable nanomedicine-based platform to hopefully curb MS-related aberrant autoreactive immune responses with higher efficacy, longer duration of action, fewer administration frequencies, and higher delivery rate to macrophages. This platform has the potential to be introduced as a vaccine for MS after clinical translation and merits further investigations.

Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases

Ferroptosis, a unique modality of cell death with mechanistic and morphological differences from other cell death modes, plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance. Aberrant epigenetic modifications and posttranslational modifications (PTMs) promote anticancer drug resistance, cancer progression, and metastasis. Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases (NSDs), cardiovascular diseases (CVDs), liver diseases, lung diseases, and kidney diseases. In this review, we first summarize the core molecular mechanisms of ferroptosis. Then, the roles of epigenetic processes, including histone PTMs, DNA methylation, and noncoding RNA regulation and PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, methylation, and ADP-ribosylation, are concisely discussed. The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases, including cancers, NSD, CVDs, liver diseases, lung diseases, and kidney diseases, as well as the application of epigenetic and PTM modulators in the therapy of these diseases, are then discussed in detail. Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases. In addition, these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases.

Small-molecule targeting AMPA-mediated excitotoxicity has therapeutic effects in mouse models for multiple sclerosis

While most research and treatments for multiple sclerosis (MS) focus on autoimmune reactions causing demyelination, it is possible that neurodegeneration precedes the autoimmune response. Hence, glutamate receptor antagonists preventing excitotoxicity showed promise in MS animal models, though blocking glutamate signaling prevents critical neuronal functions. This study reports the discovery of a small molecule that prevents AMPA-mediated excitotoxicity by targeting an allosteric binding site. A machine learning approach was used to screen for small molecules targeting the AMPA receptor GluA2 subunit. The lead candidate has potent effects in restoring neurological function and myelination while reducing the immune response in experimental autoimmune encephalitis and cuprizone MS mouse models without affecting basal neurotransmission or learning and memory. These findings facilitate development of a treatment for MS with a different mechanism of action than current immune modulatory drugs and avoids important off-target effects of glutamate receptor antagonists. This class of MS therapeutics could be useful as an alternative or complementary treatment to existing therapies.

Treatment Patterns and Unmet Need for Patients with Progressive Multiple Sclerosis in the United States: Survey Results from 2016 to 2021

INTRODUCTION

Much of the current literature on treatment patterns and disability progression in multiple sclerosis (MS) does not distinguish between the relapsing-remitting and progressive subtypes (including primary [PPMS] and secondary progressive MS [SPMS]), or between active/nonactive disease. Current treatment options for progressive MS are limited, with only one approved product for PPMS and none specifically for nonactive SPMS. Here we report treatment patterns, disability progression, and unmet needs among patients with active and nonactive PPMS and SPMS.

METHODS

The annual, cross-sectional survey from the Adelphi Disease Specific Program was used to collect physician-reported data on US adult patients with PPMS and SPMS, including active and nonactive disease. Treatment patterns (including the proportion of patients who were untreated with a disease-modifying therapy [DMT]), disability progression, and unmet need are described from 2016 to 2021.

RESULTS

Data were collected for 2067 patients with progressive MS (PPMS, 1583; SPMS, 484). A substantial proportion of patients were untreated across all groups, and this was highest for nonactive PPMS (~ 43%). The proportion of untreated patients generally declined over time but remained high in 2018-2021 (~ 10-38%). Among treated patients, the proportion receiving infusions increased over time to ~ 34-46%, largely driven by ocrelizumab use after approval. Disability progression was reported for most patients (> 50%), including many who were receiving a DMT. Across all disease subtypes, when physicians were asked about the greatest unmet need with current DMTs, they most frequently cited effectiveness (~ 63-87%), and specifically slowing disease progression (~ 32-59%).

CONCLUSIONS

This analysis of physician-reported data reveals that patients with progressive MS, particularly those with nonactive disease, frequently remain untreated or continue to decline despite treatment with available DMTs. Thus there is an enduring need for safe and effective treatments for this underserved population.

Expanding the function of oligodendrocytes to brain energy metabolism

Oligodendrocytes are best known for wrapping myelin, a unique specialization that enables energy-efficient and fast axonal impulse propagation in white matter tracts and fibers of the cortical circuitry. However, myelinating oligodendrocytes have additional metabolic functions that are only gradually understood, including the regulated release of pyruvate/lactate and extracellular vesicles, both of which are in support of the axonal energy balance. The axon-supportive functions of glial cells are older than myelin in nervous system evolution and implicate oligodendrocyte dysfunction and loss of myelin integrity as a risk factor for progressive neurodegeneration in brain diseases.

Innovative drug delivery strategies to the CNS for the treatment of multiple sclerosis

Disorders of the central nervous system (CNS), such as multiple sclerosis (MS) represent a great emotional, financial and social burden. Despite intense efforts, great unmet medical needs remain in that field. MS is an autoimmune, chronic inflammatory demyelinating disease with no curative treatment up to date. The current therapies mostly act in the periphery and seek to modulate aberrant immune responses as well as slow down the progression of the disease. Some of these therapies are associated with adverse effects related partly to their administration route and show some limitations due to their rapid clearance and inability to reach the CNS. The scientific community have recently focused their research on developing MS therapies targeting different processes within the CNS. However, delivery of therapeutics to the CNS is mainly limited by the presence of the blood-brain barrier (BBB). Therefore, there is a pressing need to develop new drug delivery strategies that ensure CNS availability to capitalize on identified therapeutic targets. Several approaches have been developed to overcome or bypass the BBB and increase delivery of therapeutics to the CNS. Among these strategies, the use of alternative routes of administration, such as the nose-to-brain (N2B) pathway, offers a promising non-invasive option in the scope of MS, as it would allow a direct transport of the drugs from the nasal cavity to the brain. Moreover, the combination of bioactive molecules within nanocarriers bring forth new opportunities for MS therapies, allowing and/or increasing their transport to the CNS. Here we will review and discuss these alternative administration routes as well as the nanocarrier approaches useful to deliver drugs for MS.

Oligodendrocyte progenitor cells differentiation induction with MAPK/ERK inhibitor fails to support repair processes in the chronically demyelinated CNS

Remyelination failure is considered a major obstacle in treating chronic-progressive multiple sclerosis (MS). Studies have shown blockage in the differentiation of resident oligodendrocyte progenitor cells (OPC) into myelin-forming cells, suggesting that pushing OPC into a differentiation program might be sufficient to overcome remyelination failure. Others stressed the need for a permissive environment to allow proper activation, migration, and differentiation of OPC. PD0325901, a MAPK/ERK inhibitor, was previously shown to induce OPC differentiation, non-specific immunosuppression, and a significant therapeutic effect in acute demyelinating MS models. We examined PD0325901 effects in the chronically inflamed central nervous system. Treatment with PD0325901 induced OPC differentiation into mature oligodendrocytes with high morphological complexity. However, treatment of Biozzi mice with chronic-progressive experimental autoimmune encephalomyelitis with PD0325901 showed no clinical improvement in comparison to the control group, no reduction in demyelination, nor induction of OPC migration into foci of demyelination. PD0325901 induced a direct general immunosuppressive effect on various cell populations, leading to a diminished phagocytic capability of microglia and less activation of lymph-node cells. It also significantly impaired the immune-modulatory functions of OPC. Our findings suggest OPC regenerative function depends on a permissive environment, which may include pro-regenerative inflammatory elements. Furthermore, they indicate that maintaining a delicate balance between the pro-myelinating and immune functions of OPC is of importance. Thus, the highly complex mission of creating a pro-regenerative environment depends upon an appropriate immune response controlled in time, place, and intensity. We suggest the need to employ a multi-systematic therapeutic approach, which cannot be achieved through a single molecule-based therapy.

The fluctuations of expression profiles of critical genes in the miRNA maturation process and pro-and anti-inflammatory cytokines in the pathogenesis and progression of multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a central nervous system disease known for immune-mediated demyelination, inflammatory, and neurodegeneration symptoms. Discovering molecular biomarkers to classify RRMS and SPMS patients, monitor the disease activity, and response to particular treatments is one area that has received notable attraction. MicroRNA (miRNA), a single-stranded non-coding RNA molecule, is a significant regulator of gene expression recruited in pathogenic mechanisms in diverse diseases, especially cancer and MS. Also, the relapsing-remitting features of MS exhibit that both inflammatory and anti-inflammatory cytokines are effective in the progression of the disease over time.

METHODS AND RESULTS

It was assessed the expression patterns of the genes (Drosha, Pasha (DGCR8), and Dicer ) encoding the critical enzymes in the processing steps of miRNA maturation and major pro-inflammatory and anti-inflammatory cytokines (IFN-α, IFN-β, and IL-6) in blood cells of 40 MS patients (two groups of 10 men and women in both clinical courses of RR and SPMS patients) in comparison with 20 healthy control group (10 males and 10 females). The highest transcription activity of Drosha was observed for RRMS patients (4.2 and 3.6-fold, respectively), and the expression ratio was down regulated in male and female patients with SPMS (3.9- and 3.1-fold, respectively). Considering the studied cytokines, the increase in expression ratio of IL-6 in SPMS patients and the decrease in transcript abundance of INF-α, and INF-β cytokines are consistent with the progression of the disease.

CONCLUSIONS

Our findings showed that the high and low transcriptional levels of the considered genes seem to be effective in the pathogenesis and progression of MS.

Visual function resists early neurodegeneration in the visual system in primary progressive multiple sclerosis

BACKGROUND

Neurodegeneration in multiple sclerosis (MS) affects the visual system but dynamics and pathomechanisms over several years especially in primary progressive MS (PPMS) are not fully understood.

METHODS

We assessed longitudinal changes in visual function, retinal neurodegeneration using optical coherence tomography, MRI and serum NfL (sNfL) levels in a prospective PPMS cohort and matched healthy controls. We investigated the changes over time, correlations between outcomes and with loss of visual function.

RESULTS

We followed 81 patients with PPMS (mean disease duration 5.9 years) over 2.7 years on average. Retinal nerve fibre layer thickness (RNFL) was reduced in comparison with controls (90.1 vs 97.8 µm; p<0.001). Visual function quantified by the area under the log contrast sensitivity function (AULCSF) remained stable over a continuous loss of RNFL (0.46 µm/year, 95% CI 0.10 to 0.82; p=0.015) up until a mean turning point of 91 µm from which the AULCSF deteriorated. Intereye RNFL asymmetry above 6 µm, suggestive of subclinical optic neuritis, occurred in 15 patients and was related to lower AULCSF but occurred also in 5 out of 44 controls. Patients with an AULCSF progression had a faster increase in Expanded Disability Status Scale (beta=0.17/year, p=0.043). sNfL levels were elevated in patients (12.2 pg/mL vs 8.0 pg/mL, p<0.001), but remained stable during follow-up (beta=-0.14 pg/mL/year, p=0.291) and were not associated with other outcomes.

CONCLUSION

Whereas neurodegeneration in the anterior visual system is already present at onset, visual function is not impaired until a certain turning point. sNfL is not correlated with structural or functional impairment in the visual system.

Lethal adulthood myelin breakdown by oligodendrocyte-specific Ddx54 knockout

Multiple sclerosis (MS) is a leading disease that causes disability in young adults. We have previously shown that a DEAD-box RNA helicase Ddx54 binds to mRNA and protein isoforms of myelin basic protein (MBP) and that Ddx54 siRNA blocking abrogates oligodendrocyte migration and myelination. Herein, we show that MBP-driven Ddx54 knockout mice (Ddx54 fl/fl;MBP-Cre), after the completion of normal postnatal myelination, gradually develop abnormalities in behavioral profiles and learning ability, inner myelin sheath breakdown, loss of myelinated axons, apoptosis of oligodendrocytes, astrocyte and microglia activation, and they die within 7 months but show minimal peripheral immune cell infiltration. Myelin in Ddx54fl/fl;MBP-Cre is highly vulnerable to the neurotoxicant cuprizone and Ddx54 knockdown greatly impairs myelination in vitro. Ddx54 expression in oligodendrocyte-lineage cells decreased in corpus callosum of MS patients. Our results demonstrate that Ddx54 is indispensable for myelin homeostasis, and they provide a demyelinating disease model based on intrinsic disintegration of adult myelin.

[Over one year of B‑cell targeted therapy with Ofatumumab s.c.: first results of a prospective, patient-centered real-world observational study]

INTRODUCTION

Ofatumumab (Kesimpta™) is a s.c. applicable anti-CD20 antibody, which has been used in Germany since 2021 for the treatment of relapsing multiple sclerosis (RMS). The self-application offers a high degree of independence from intravenous forms of application with highly effective immunotherapy. In this study we recorded the patient-centered experience in 99 out of 127 patients who were adjusted to the drug by us. The aim was to investigate the tolerability and acceptance from the patient's perspective.

METHODS

Data collection was carried out using doctor documentation, questionnaires and telephone interviews.

RESULTS

The cohort consists of 127 patients. The patients received 2.8 (± SD 1.7) pre-therapies. The mean duration of therapy with Ofatumumab was 9.8 months (± SD 3.5). Structured data were collected from 99 patients. 23% of patients had no side effects during initial application. 19% rated the side effects as "very mild" and 18% as "mild". In addition to chills/fever (48%), headache (46%), limb pain (45%) and "other symptoms" (19%) also occurred. For subsequent injections, 72% of patients reported no side effects. 87% of patients found handling the medication "very easy". There was one relapse event during therapy.

CONCLUSION

Our study shows that Ofatumumab is well accepted and tolerated by patients. There was one relapse event during the observation period. The side effects are mild and occur during initial application. No increased tendency to infection could be observed. The data suggest that Ofatumumab is also an effective and safe treatment option for patients with relapsing remitting multiple sclerosis in real-world use.

Mesenchymal Stem Cell Therapy in Multiple Sclerosis: A Systematic Review and Meta-Analysis

The assurance of safety and effectiveness is a significant focal point in all therapeutic approaches. Although mesenchymal stem cells (MSCs) have been identified as a potential novel therapeutic strategy for multiple sclerosis (MS), existing evidence regarding the effectiveness and safety of this strategy remains inconclusive. Thus, the primary aim of this systematic review and meta-analysis (SRMA) was to comprehensively assess the effectiveness and safety of MSC therapy in individuals diagnosed with MS. A comprehensive search was conducted using appropriate keywords in the PubMed, Scopus, Cochrane, ScienceDirect, and Google Scholar databases to determine the eligible studies. The change in the expanded disability status scale (EDSS) score from baseline to follow-up was used to assess MSC efficacy. The effectiveness of the therapy was assessed using a random-effects model, which calculated the combined prevalence and 95% confidence intervals (CIs) for MS patients who experienced improvement, stability, or worsening of their condition. The protocol was registered in PROSPERO (CRD42020209671). The findings indicate that 40.4% (95% CI: 30.6-50.2) of MS patients exhibited improvements following MSC therapy, 32.8% (95% CI: 25.5-40.1) remained stable, and 18.1% (95% CI: 12.0-24.2) experienced a worsening of their condition. Although no major complications were observed, headaches 57.6 [37.9-77.3] and fever 53.1 [20.7-85.4] were commonly reported as minor adverse events. All of the results reported in this meta-analysis are consistent and credible according to the sensitivity analyses. Regardless of different individual studies, our meta-analysis provides a comprehensive overview showing the potential of MSC therapy as a possible effective treatment strategy for patients with MS.

Mechanisms underlying the beneficial effects of physical exercise on multiple sclerosis: focus on immune cells

Multiple sclerosis (MS) is a prevalent neuroimmunological illness that leads to neurological disability in young adults. Although the etiology of MS is heterogeneous, it is well established that aberrant activity of adaptive and innate immune cells plays a crucial role in its pathogenesis. Several immune cell abnormalities have been described in MS and its animal models, including T lymphocytes, B lymphocytes, dendritic cells, neutrophils, microglia/macrophages, and astrocytes, among others. Physical exercise offers a valuable alternative or adjunctive disease-modifying therapy for MS. A growing body of evidence indicates that exercise may reduce the autoimmune responses triggered by immune cells in MS. This is partially accomplished by restricting the infiltration of peripheral immune cells into the central nervous system (CNS) parenchyma, curbing hyperactivation of immune cells, and facilitating a transition in the balance of immune cells from a pro-inflammatory to an anti-inflammatory state. This review provides a succinct overview of the correlation between physical exercise, immune cells, and MS pathology, and highlights the potential benefits of exercise as a strategy for the prevention and treatment of MS.

Nose to brain delivery of Astragaloside IV by β-Asarone modified chitosan nanoparticles for multiple sclerosis therapy

Multiple sclerosis (MS), an autoimmune disease, has been considered an inflammatory disorder of the central nervous system (CNS) with demyelination and axonal damage. Although there are certain first-line therapies to treat MS, their unsatisfactory efficacy is partly due to the limited CNS access after systemic administration. Besides, there is an urgent need to treat MS by enhancing remyelination or neuroprotection, or dampen the activity of microglia. Astragaloside IV (ASI) bears anti-inflammatory, antioxidant, remyelination and neuroprotective activity. While its poor permeability, relatively high molecular weight and low lipophilicity restrict it to reach the brain. Therefore, β-asarone modified ASI loaded chitosan nanoparticles (ASI-βCS-NP) were prepared to enhance the nose-to-brain delivery and therapeutic effects of ASI on EAE mice. The prepared ASI-βCS-NP showed mean size of about 120 nm, and zeta potential from +19 to +25 mV. DiR-βCS-NP was confirmed with good nose-to-brain targeting ability. After intranasal administration, the ASI-βCS-NP significantly reduced behavioral scores, decreased weight loss, suppressed inflammatory infiltration and astrocyte/microglial activation, reduced demyelination and increased remyelination on a mice EAE model. Our findings indicate that ASI-βCS-NP may be a potent treatment for MS after nose-to-brain drug delivery.

Neurodegeneration and its potential markers in the diagnosing of secondary progressive multiple sclerosis. A review

Approximately 70% of relapsing-remitting multiple sclerosis (RRMS) patients will develop secondary progressive multiple sclerosis (SPMS) within 10-15 years. This progression is characterized by a gradual decline in neurological functionality and increasing limitations of daily activities. Growing evidence suggests that both inflammation and neurodegeneration are associated with various pathological processes throughout the development of MS; therefore, to delay disease progression, it is critical to initiate disease-modifying therapy as soon as it is diagnosed. Currently, a diagnosis of SPMS requires a retrospective assessment of physical disability exacerbation, usually over the previous 6-12 months, which results in a delay of up to 3 years. Hence, there is a need to identify reliable and objective biomarkers for predicting and defining SPMS conversion. This review presents current knowledge of such biomarkers in the context of neurodegeneration associated with MS, and SPMS conversion.

Mechanosensitive Piezo1 channel in physiology and pathophysiology of the central nervous system

Since the discovery of the mechanosensitive Piezo1 channel in 2010, there has been a significant amount of research conducted to explore its regulatory role in the physiology and pathology of various organ systems. Recently, a growing body of compelling evidence has emerged linking the activity of the mechanosensitive Piezo1 channel to health and disease of the central nervous system. However, the exact mechanisms underlying these associations remain inadequately comprehended. This review systematically summarizes the current research on the mechanosensitive Piezo1 channel and its implications for central nervous system mechanobiology, retrospects the results demonstrating the regulatory role of the mechanosensitive Piezo1 channel on various cell types within the central nervous system, including neural stem cells, neurons, oligodendrocytes, microglia, astrocytes, and brain endothelial cells. Furthermore, the review discusses the current understanding of the involvement of the Piezo1 channel in central nervous system disorders, such as Alzheimer's disease, multiple sclerosis, glaucoma, stroke, and glioma.

Platelet mitochondria, a potent immune mediator in neurological diseases

Dysfunction of the immune response is regarded as a prominent feature of neurological diseases, including neurodegenerative diseases, malignant tumors, acute neurotraumatic insult, and cerebral ischemic/hemorrhagic diseases. Platelets play a fundamental role in normal hemostasis and thrombosis. Beyond those normal functions, platelets are hyperactivated and contribute crucially to inflammation and immune responses in the central nervous system (CNS). Mitochondria are pivotal organelles in platelets and are responsible for generating most of the ATP that is used for platelet activation and aggregation (clumping). Notably, platelet mitochondria show marked morphological and functional alterations under heightened inflammatory/oxidative stimulation. Mitochondrial dysfunction not only leads to platelet damage and apoptosis but also further aggravates immune responses. Improving mitochondrial function is hopefully an effective strategy for treating neurological diseases. In this review, the authors discuss the immunomodulatory roles of platelet-derived mitochondria (PLT-mitos) in neurological diseases and summarize the neuroprotective effects of platelet mitochondria transplantation.

PKC modulator bryostatin-1 therapeutically targets CNS innate immunity to attenuate neuroinflammation and promote remyelination

In multiple sclerosis (MS), microglia and macrophages within the central nervous system (CNS) play an important role in determining the balance between myelin repair and demyelination/neurodegeneration. Phagocytic and regenerative functions of these CNS innate immune cells support remyelination, whereas chronic and maladaptive inflammatory activation promotes lesion expansion and disability, particularly in the progressive forms of MS. No currently approved drugs convincingly target microglia and macrophages within the CNS, contributing to the critical lack of therapies promoting remyelination and slowing progression in MS. Here, we found that the protein kinase C (PKC)-modulating drug bryostatin-1 (bryo-1), a CNS-penetrant compound with an established human safety profile, produces a shift in microglia and CNS macrophage transcriptional programs from pro-inflammatory to regenerative phenotypes, both in vitro and in vivo. Treatment of microglia with bryo-1 prevented the activation of neurotoxic astrocytes while stimulating scavenger pathways, phagocytosis, and secretion of factors that promote oligodendrocyte differentiation. In line with these findings, systemic treatment with bryo-1 augmented remyelination following a focal demyelinating injury in vivo. Our results demonstrate the potential of bryo-1 and functionally related PKC modulators as myelin regenerative and neuroprotective agents in MS and other neurologic diseases through therapeutic targeting of microglia and CNS-associated macrophages.

Pediatric multiple sclerosis: an integrated outlook at the interplay between genetics, environment and brain-gut dysbiosis

Multiple sclerosis (MS) is a debilitating autoimmune condition caused by demyelination, neurodegeneration and persistent inflammation of the central nervous system. Pediatric multiple sclerosis (PMS) is a relatively rare form of the disease that affects a significant number of individuals with MS. Environmental exposures, such as viral infections and smoking, can interact with MS-associated human leukocyte antigens (HLA) risk alleles and influence the immune response. Upregulation of immune response results in the disruption of immune balance leading to cascade of inflammatory events. It has also been established that gut microbiome dysbiosis poses a higher risk for pro-inflammation, and it is essentially argued to be the greatest environmental risk factor for MS. Dysbiosis can cause an unusual response from the adaptive immune system and significantly contribute to the development of disease in the host by activating pro-inflammatory pathways that cause immune-mediated disorders such as PMS, rendering the body more vulnerable to foreign attacks due to a weakened immune response. All these dynamic interactions between biological, environmental and genetic factors based on epigenetic study has further revealed that upregulation or downregulation of some genes/enzyme in the central nervous system white matter of MS patients produces a less stable form of myelin basic protein and ultimately leads to the loss of immune tolerance. The diagnostic criteria and treatment options for PMS are constantly evolving, making it crucial to have a better understanding of the disease burden on a global and regional scale. The findings from this review will aid in deepening the understanding of the interplay between genetic and environmental risk factors, as well as the role of the gut microbiome in the development of pediatric multiple sclerosis. As a result, healthcare professionals will be kept abreast of the early diagnostic criteria, accurately delineating other conditions that can mimic pediatric MS and to provide comprehensive care to individuals with PMS based on the knowledge gained from this research.

Quantitative magnetic resonance mapping of the myelin bilayer reflects pathology in multiple sclerosis brain tissue

Multiple sclerosis (MS) is a neuroinflammatory disease characterized by loss of myelin (demyelination) and, to a certain extent, subsequent myelin repair (remyelination). To better understand the pathomechanisms underlying de- and remyelination and to monitor the efficacy of treatments aimed at regenerating myelin, techniques offering noninvasive visualizations of myelin are warranted. Magnetic resonance (MR) imaging has long been at the forefront of efforts to visualize myelin, but it has only recently become feasible to access the rapidly decaying resonance signals stemming from the myelin lipid-protein bilayer itself. Here, we show that direct MR mapping of the bilayer yields highly specific myelin maps in brain tissue from patients with MS. Furthermore, examination of the bilayer signal behavior is found to reveal pathological alterations in normal-appearing white and gray matter. These results indicate promise for in vivo implementations of the myelin bilayer mapping technique, with prospective applications in basic research, diagnostics, disease monitoring, and drug development.

Progressive post infectious neurological syndromes with a poor outcome: Long term follow-up and neurofilament light chain quantification

Postinfectious neurological syndromes (PINS), among which acute disseminated encephalomyelitis (ADEM), are inflammatory and mostly monophasic disorders. We previously reported that PINS patients can show relapses, or even disease progression. Here we describe a cohort of patients with progressive-PINS and >5 years of follow-up, that developed a progressive worsening without radiological/cerebrospinal fluid analysis evidence of inflammation. At onset 5 patients fulfilled diagnostic criteria for ADEM and none for MS. Progression occurred after a median of 22 months from onset (in 4/7 after 1/more relapses), manifesting as ascending tetraparesis with bulbar functions involvement in 5/7. Five/7 patients received high dose steroids and/or IvIG and 6/7 Rituximab(n = 4) and/or cyclophosphamide(n = 2), with no impact on disease progression in 6/7. NfL levels were higher in patients with progressive-PINS compared to monophasic-ADEM (p = 0.023) and healthy controls (p = 0.004). Progression is rare, but possible, in PINS. Immunotherapy seems to be ineffective in these patients, and elevated serum NfL in serum suggest persistent axonal damage.

Cerebrospinal fluid inflammatory biomarkers for disease progression in Alzheimer's disease and multiple sclerosis: a systematic review

Inflammatory processes are involved in the pathophysiology of both Alzheimer's disease (AD) and multiple sclerosis (MS) but their exact contribution to disease progression remains to be deciphered. Biomarkers are needed to define pathophysiological processes of these disorders, who may increasingly co-exist in the elderly generations of the future, due to the rising prevalence in both and ameliorated treatment options with improved life expectancy in MS. The purpose of this review was to provide a systematic overview of inflammatory biomarkers, as measured in the cerebrospinal fluid (CSF), that are associated with clinical disease progression. International peer-reviewed literature was screened using the PubMed and Web of Science databases. Disease progression had to be measured using clinically validated tests representing baseline functional and/or cognitive status, the evolution of such clinical scores over time and/or the transitioning from one disease stage to a more severe stage. The quality of included studies was systematically evaluated using a set of questions for clinical, neurochemical and statistical characteristics of the study. A total of 84 papers were included (twenty-five for AD and 59 for MS). Elevated CSF levels of chitinase-3-like protein 1 (YKL-40) were associated with disease progression in both AD and MS. Osteopontin and monocyte chemoattractant protein-1 were more specifically related to disease progression in AD, whereas the same was true for interleukin-1 beta, tumor necrosis factor alpha, C-X-C motif ligand 13, glial fibrillary acidic protein and IgG oligoclonal bands in MS. We observed a broad heterogeneity of studies with varying cohort characterization, non-disclosure of quality measures for neurochemical analyses and a lack of adequate longitudinal designs. Most of the retrieved biomarkers are related to innate immune system activity, which seems to be an important mediator of clinical disease progression in AD and MS. Overall study quality was limited and we have framed some recommendations for future biomarker research in this field.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021264741.

Bruton's tyrosine kinase inhibition reduces disease severity in a model of secondary progressive autoimmune demyelination

Bruton's tyrosine kinase (BTK) is an emerging target in multiple sclerosis (MS). Alongside its role in B cell receptor signaling and B cell development, BTK regulates myeloid cell activation and inflammatory responses. Here we demonstrate efficacy of BTK inhibition in a model of secondary progressive autoimmune demyelination in Biozzi mice with experimental autoimmune encephalomyelitis (EAE). We show that late in the course of disease, EAE severity could not be reduced with a potent relapse inhibitor, FTY720 (fingolimod), indicating that disease was relapse-independent. During this same phase of disease, treatment with a BTK inhibitor reduced both EAE severity and demyelination compared to vehicle treatment. Compared to vehicle treatment, late therapeutic BTK inhibition resulted in fewer spinal cord-infiltrating myeloid cells, with lower expression of CD86, pro-IL-1β, CD206, and Iba1, and higher expression of Arg1, in both tissue-resident and infiltrating myeloid cells, suggesting a less inflammatory myeloid cell milieu. These changes were accompanied by decreased spinal cord axonal damage. We show similar efficacy with two small molecule inhibitors, including a novel, highly selective, central nervous system-penetrant BTK inhibitor, GB7208. These results suggest that through lymphoid and myeloid cell regulation, BTK inhibition reduced neurodegeneration and disease progression during secondary progressive EAE.

Implications of immunometabolism for smouldering MS pathology and therapy

Clinical symptom worsening in patients with multiple sclerosis (MS) is driven by inflammation compartmentalized within the CNS, which results in chronic neuronal damage owing to insufficient repair mechanisms. The term 'smouldering inflammation' summarizes the biological aspects underlying this chronic, non-relapsing and immune-mediated mechanism of disease progression. Smouldering inflammation is likely to be shaped and sustained by local factors in the CNS that account for the persistence of this inflammatory response and explain why current treatments for MS do not sufficiently target this process. Local factors that affect the metabolic properties of glial cells and neurons include cytokines, pH value, lactate levels and nutrient availability. This Review summarizes current knowledge of the local inflammatory microenvironment in smouldering inflammation and how it interacts with the metabolism of tissue-resident immune cells, thereby promoting inflammatory niches within the CNS. The discussion highlights environmental and lifestyle factors that are increasingly recognized as capable of altering immune cell metabolism and potentially responsible for smouldering pathology in the CNS. Currently approved MS therapies that target metabolic pathways are also discussed, along with their potential for preventing the processes that contribute to smouldering inflammation and thereby to progressive neurodegenerative damage in MS.

Nanomaterials for antigen-specific immune tolerance therapy

Impairment of immune tolerance might cause autologous tissue damage or overactive immune response against non-pathogenic molecules. Although autoimmune disease and allergy have complicated pathologies, the current strategies have mainly focused on symptom amelioration or systemic immunosuppression which can lead to fatal adverse events. The induction of antigen-specific immune tolerance may provide therapeutic benefits to autoimmune disease and allergic response, while reducing nonspecific immune adverse responses. Diverse nanomaterials have been studied to induce antigen-specific immune tolerance therapy. This review will cover the immunological background of antigen-specific tolerance, clinical importance of antigen-specific immune tolerance, and nanomaterials designed for autoimmune and allergic diseases. As nanomaterials for modulating immune tolerances, lipid-based nanoparticles, polymeric nanoparticles, and biological carriers have been covered. Strategies to provide antigen-specific immune tolerance have been addressed. Finally, current challenges and perspectives of nanomaterials for antigen-specific immune tolerance therapy will be discussed.

A safety review of current monoclonal antibodies used to treat multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system. Monoclonal antibodies (mAbs) have shown efficacy in reducing MS relapse rates, disease progression, and brain lesion activity.

AREAS COVERED

This article reviews the literature on the use of mAbs for the treatment of MS, including their mechanisms of action, clinical trial data, safety profiles, and long-term outcomes. The review focuses on the three main categories of mAbs used in MS: alemtuzumab, natalizumab, and anti-CD20 drugs. A literature search was conducted using relevant keywords and guidelines and reports from regulatory agencies were reviewed. The search covered studies published from inception to 31 December 202231 December 2022. The article also discusses the potential risks and benefits of these therapies, including their effects on infection rates, malignancies, and vaccination efficacy.

EXPERT OPINION

Monoclonal antibodies have revolutionized the treatment of MS, but safety concerns must be considered, particularly with regards to infection rates, malignancy risk, and vaccination efficacy. Clinicians must weigh the potential benefits and risks of mAbs on an individual patient basis, taking into account factors such as age, disease severity, and comorbidities. Ongoing monitoring and surveillance are essential to ensure the long-term safety and effectiveness of monoclonal antibody therapies in MS.

Granzyme B + CD8 + T cells with terminal differentiated effector signature determine multiple sclerosis progression

BACKGROUND

Multiple sclerosis (MS) leads to demyelination and neurodegeneration with autoimmune responses in central nervous system. Patients begin with a relapsing-remitting (RR) course, and more than 80% of them may advance to secondary progressive MS (SPMS), which is characteristic for the gradual decline of neurological functions without demonstrated treating method to prevent. This study aims to investigate the contribution of peripheral CD8 + T cells during the conversion from RRMS to SPMS, as well as reveal potential diagnostic signature in distinguishing SPMS.

METHODS

Single-cell RNA sequencing was employed to reveal the heterogeneity of CD8 + T cells between SPMS and RRMS. In addition, flow cytometry was used to further characterized CD8 + T cell dynamic changes in patients. T cell receptor sequencing was performed to detect the clonal expansion of MS. Using Tbx21 siRNA, T-bet was confirmed to manipulate GzmB expression. The correlation between GzmB + CD8 + T cell subsets and clinical characteristics of MS and their potential diagnostic value for SPMS were evaluated by generalized linear regression models and receiver operating characteristic (ROC) curve respectively.

RESULTS

Other than diminished naïve CD8 + T cell, elevating of activated CD8 + T cell subsets were observed in SPMS patients. Meanwhile, this aberrant amplified peripheral CD8 + T cells not only exhibited terminal differentiated effector (EMRA) phenotype with GzmB expression, but also possessed distinct trajectory from clonal expansion. In addition, T-bet acted as a key transcriptional factor that elicited GzmB expression in CD8 + T_EMRA cells of patients with SPMS. Finally, the expression of GzmB in CD8 + T cells was positively correlated with disability and progression of MS, and could effectively distinguish SPMS from RRMS with a high accuracy.

CONCLUSIONS

Our study mapped peripheral immune cells of RRMS and SPMS patients and provided an evidence for the involvement of GzmB + CD8 + T_EMRA cells in the progression of MS, which could be used as a diagnostic biomarker for distinguishing SPMS from RRMS.

Moving forward through the in silico modeling of multiple sclerosis: Treatment layer implementation and validation

Multiple sclerosis is an autoimmune inflammatory disease that affects the central nervous system through chronic demyelination and loss of oligodendrocytes. Since the relapsing-remitting form is the most prevalent, relapse-reducing therapies are a primary choice for specialists. Universal Immune System Simulator is an agent-based model that simulates the human immune system dynamics under physiological conditions and during several diseases, including multiple sclerosis. In this work, we extended the UISS-MS disease layer by adding two new treatments, i.e., cladribine and ocrelizumab, to show that UISS-MS can be potentially used to predict the effects of any existing or newly designed treatment against multiple sclerosis. To retrospectively validate UISS-MS with ocrelizumab and cladribine, we extracted the clinical and MRI data from patients included in two clinical trials, thus creating specific cohorts of digital patients for predicting and validating the effects of the considered drugs. The obtained results mirror those of the clinical trials, demonstrating that UISS-MS can correctly simulate the mechanisms of action and outcomes of the treatments. The successful retrospective validation concurred to confirm that UISS-MS can be considered a digital twin solution to be used as a support system to inform clinical decisions and predict disease course and therapeutic response at a single patient level.

Central nervous system demyelinating diseases: glial cells at the hub of pathology

Inflammatory demyelinating diseases (IDDs) are among the main causes of inflammatory and neurodegenerative injury of the central nervous system (CNS) in young adult patients. Of these, multiple sclerosis (MS) is the most frequent and studied, as it affects about a million people in the USA alone. The understanding of the mechanisms underlying their pathology has been advancing, although there are still no highly effective disease-modifying treatments for the progressive symptoms and disability in the late stages of disease. Among these mechanisms, the action of glial cells upon lesion and regeneration has become a prominent research topic, helped not only by the discovery of glia as targets of autoantibodies, but also by their role on CNS homeostasis and neuroinflammation. In the present article, we discuss the participation of glial cells in IDDs, as well as their association with demyelination and synaptic dysfunction throughout the course of the disease and in experimental models, with a focus on MS phenotypes. Further, we discuss the involvement of microglia and astrocytes in lesion formation and organization, remyelination, synaptic induction and pruning through different signaling pathways. We argue that evidence of the several glia-mediated mechanisms in the course of CNS demyelinating diseases supports glial cells as viable targets for therapy development.

Single-cell analysis reveals inflammatory interactions driving macular degeneration

Due to commonalities in pathophysiology, age-related macular degeneration (AMD) represents a uniquely accessible model to investigate therapies for neurodegenerative diseases, leading us to examine whether pathways of disease progression are shared across neurodegenerative conditions. Here we use single-nucleus RNA sequencing to profile lesions from 11 postmortem human retinas with age-related macular degeneration and 6 control retinas with no history of retinal disease. We create a machine-learning pipeline based on recent advances in data geometry and topology and identify activated glial populations enriched in the early phase of disease. Examining single-cell data from Alzheimer's disease and progressive multiple sclerosis with our pipeline, we find a similar glial activation profile enriched in the early phase of these neurodegenerative diseases. In late-stage age-related macular degeneration, we identify a microglia-to-astrocyte signaling axis mediated by interleukin-1β which drives angiogenesis characteristic of disease pathogenesis. We validated this mechanism using in vitro and in vivo assays in mouse, identifying a possible new therapeutic target for AMD and possibly other neurodegenerative conditions. Thus, due to shared glial states, the retina provides a potential system for investigating therapeutic approaches in neurodegenerative diseases.

Posttranscriptional Regulation of Gene Expression Participates in the Myelin Restoration in Mouse Models of Multiple Sclerosis: Antisense Modulation of HuR and HuD ELAV RNA Binding Protein

Neuropathic pain is the most difficult-to-treat pain syndrome in multiple sclerosis. Evidence relates neuropathic pain to demyelination, which often originates from unresolved neuroinflammation or altered immune response. Posttranscriptional regulation of gene expression might play a fundamental role in the regulation of these processes. The ELAV RNA-binding proteins HuR and HuD are involved in the promotion of inflammatory phenomena and in neuronal development and maintenance, respectively. Thus, the aim of this study was to investigate the role of HuR and HuD in demyelination-associated neuropathic pain in the mouse experimental autoimmune encephalomyelitis (EAE) model. HuR resulted overexpressed in the spinal cord of MOG_35-55-EAE and PLP_139-151-EAE mice and was detected in CD11b + cells. Conversely, HuD was largely downregulated in the MOG-EAE spinal cord, along with GAP43 and neurofilament H, while in PLP-EAE mice, HuD and neuronal markers remained unaltered. Intranasal antisense oligonucleotide (ASO) delivery to knockdown HuR, increased myelin basic protein expression, and Luxol Fast Blue staining in both EAE models, an indication of increased myelin content. These effects temporally coincided with attenuation of pain hypersensitivity. Anti-HuR ASO increased the expression of HuD in GAP43-expressing cells and promoted a HuD-mediated neuroprotective activity in MOG-EAE mice, while in PLP-EAE mice, HuR silencing dampened pro-inflammatory responses mediated by spinal microglia activation. In conclusion, anti-HuR ASO showed myelin protection at analgesic doses with multitarget mechanisms, and it deserves further consideration as an innovative agent to counteract demyelination in neuropathic pain states.

Bruton tyrosine kinase inhibitors for multiple sclerosis

Current therapies for multiple sclerosis (MS) reduce both relapses and relapse-associated worsening of disability, which is assumed to be mainly associated with transient infiltration of peripheral immune cells into the central nervous system (CNS). However, approved therapies are less effective at slowing disability accumulation in patients with MS, in part owing to their lack of relevant effects on CNS-compartmentalized inflammation, which has been proposed to drive disability. Bruton tyrosine kinase (BTK) is an intracellular signalling molecule involved in the regulation of maturation, survival, migration and activation of B cells and microglia. As CNS-compartmentalized B cells and microglia are considered central to the immunopathogenesis of progressive MS, treatment with CNS-penetrant BTK inhibitors might curtail disease progression by targeting immune cells on both sides of the blood-brain barrier. Five BTK inhibitors that differ in selectivity, strength of inhibition, binding mechanisms and ability to modulate immune cells within the CNS are currently under investigation in clinical trials as a treatment for MS. This Review describes the role of BTK in various immune cells implicated in MS, provides an overview of preclinical data on BTK inhibitors and discusses the (largely preliminary) data from clinical trials.

Cycling in primary progressive multiple sclerosis (CYPRO): study protocol for a randomized controlled superiority trial evaluating the effects of high-intensity interval training in persons with primary progressive multiple sclerosis

BACKGROUND

Primary progressive multiple sclerosis (PPMS) is the least prevalent multiple sclerosis (MS) phenotype. For persons with PPMS (pwPPMS), pharmacological treatment options are limited. As a complementary non-pharmacological treatment, endurance training improves the health-related quality of life (HRQoL), numerous MS symptoms, and MS-related performance impediments. High-intensity interval training (HIIT) has been shown to induce superior effects compared to moderate-intensity continuous training (MCT). As current evidence is based on MS samples with mixed phenotypes, generalizability to pwPPMS remains unclear.

METHODS

CYPRO is a parallel-group, single-center, and single-blind randomized controlled superiority trial evaluating the effects of HIIT compared to MCT in pwPPMS. Sixty-one pwPPMS are randomized (1:1) to perform volume-matched HIIT or MCT sessions on bicycle ergometers two to three times per week in addition to standard rehabilitative care during their three-week inpatient stay at Valens rehabilitation clinic, Switzerland. Standard rehabilitative care comprises endurance and strength training, physiotherapy, and occupational therapy. HIIT sessions include six 90-second intervals at 95% peak heart rate (HR_peak), interspersed by 90-second active breaks with unloaded pedaling, aimed to reach 60%HR_peak. MCT represents the standard treatment at Valens rehabilitation clinic and is performed as continuous cycling at 60%HR_peak for the duration of 26 minutes. The primary outcome is cardiorespiratory fitness, assessed as peak oxygen consumption (V̇O_2peak) during cardiopulmonary exercise testing (CPET). Secondary outcomes include peak power output during CPET, walking capacity, cognitive performance, HRQoL, fatigue, anxiety and depressive symptoms, and blood-derived biomarkers (e.g., serum neurofilament light chain, glial fibrillary acidic protein, kynurenine pathway metabolites) related to MS pathophysiology. All outcomes are assessed at baseline and discharge after three weeks. Venous blood sampling is additionally performed immediately and two hours after the first HIIT or MCT session.

DISCUSSION

CYPRO will expand current knowledge on symptom management and rehabilitation in MS to the subpopulation of pwPPMS, and will contribute to the exploration of potential disease-modifying effects of endurance training in MS. The superiority design of CYPRO will allow deriving explicit recommendations on endurance training design in pwPPMS that can be readily translated into clinical practice.

TRIAL REGISTRATION

CYPRO has been prospectively registered at ClinicalTrials.gov on 8 February 2022 (NCT05229861).

Activation of TRPV1 receptor facilitates myelin repair following demyelination via the regulation of microglial function

The transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel that is activated by capsaicin (CAP), the main component of chili pepper. Despite studies in several neurological diseases, the role of TRPV1 in demyelinating diseases remains unknown. Herein, we reported that TRPV1 expression was increased within the corpus callosum during demyelination in a cuprizone (CPZ)-induced demyelination mouse model. TRPV1 deficiency exacerbated motor coordinative dysfunction and demyelination in CPZ-treated mice, whereas the TRPV1 agonist CAP improved the behavioral performance and facilitated remyelination. TRPV1 was predominantly expressed in Iba1+ microglia/macrophages in human brain sections of multiple sclerosis patients and mouse corpus callosum under demyelinating conditions. TRPV1 deficiency decreased microglial recruitment to the corpus callosum, with an associated increase in the accumulation of myelin debris. Conversely, the activation of TRPV1 by CAP enhanced the recruitment of microglia to the corpus callosum and potentiated myelin debris clearance. Using real-time live imaging we confirmed an increased phagocytic function of microglia following CAP treatment. In addition, the expression of the scavenger receptor CD36 was increased, and that of the glycolysis regulators Hif1a and Hk2 was decreased. We conclude that TRPV1 is an important regulator of microglial function in the context of demyelination and may serve as a promising therapeutic target for demyelinating diseases such as multiple sclerosis.

Icariin ameliorates behavioral deficits and neuropathology in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is a systemic inflammatory illness of the central nervous system that involves demyelinating lesions in the myelin-rich white matter and pathology in the grey matter. Despite significant advancements in drug research for MS, the disease's complex pathophysiology makes it difficult to treat the progressive forms of the disease. In this study, we identified a natural flavonoid compound icariin (ICA) as a potent effective agent for MS in ameliorating the deterioration of symptoms including the neurological deficit score and the body weight in a murine experimental autoimmune encephalomyelitis (EAE) model. These improvements were associated with decreased demyelination in the corpus callosum and neuron loss in the hippocampus and cortex confirmed by immunohistochemistry analysis. Meanwhile, it was observed that the activation of microglia in cerebral cortex and hippocampus were inhibited followed by the neuroinflammatory cytokines downregulation such as IL-1β, IL-6 and TNF-α after ICA treatment, which was probably attributable to the suppression of microglial NLRP3 inflammasome activation. Additionally, molecular docking also revealed the binding force of ICA to NLRP3 inflammasome protein complexes in vitro. Taken together, our findings have demonstrated that ICA, as pleiotropic agent, prevents EAE-induced MS by improving demyelination and neuron loss, which interferes with the neuroinflammation via microglial NLRP3 inflammasome activation.

Neuroprotective effect of Vesatolimod in an experimental autoimmune encephalomyelitis mice model

BACKGROUND

Multiple sclerosis is a chronic demyelinating autoimmune disease accompanied by inflammation and loss of axons and neurons. Toll-like receptors play crucial roles in the innate immune system and inflammation. However, few studies have explored the specific effects of toll-like receptor 7 signaling pathway in multiple sclerosis. To explore underlying effects to develop a new therapeutic target, we use Vesatolimod, a safe and well-tolerated agonist of toll-like receptor 7, to assess the possible effects in Experimental autoimmune encephalomyelitis (EAE) animal model.

METHODS

EAE animal model was induced by injection of MOG35-55 and monitored daily for clinical symptoms, and the treatment group was given Vesatolimod at the onset of illness. The therapeutic effects of Vesatolimod on EAE inflammation, demyelination, CD107b cells and T cells infiltration, and microglia activation was evaluated. Autophagy within the spinal cords of EAE mice was also preliminarily assessed.

RESULTS

Treatment with Vesatolimod significantly alleviated clinical symptoms of EAE from day 18 post-immunization and decreased the expression levels of inflammatory cytokines, particularly Eotaxin and IL-12 (P40), in peripheral blood. It also inhibited demyelination in spinal cords. Moreover, VES treatment reduced activation of microglia, infiltration of CD3 + T cells and CD107b + cells, as well as inhibited the autophagy-related proteins expression in the spinal cords of EAE mice.

CONCLUSION

Our results indicate that Vesatolimod exhibits protective effects on EAE mice and is promising for treatment of MS.

Lessons from immunotherapies in multiple sclerosis

The improved understanding of multiple sclerosis (MS) neurobiology alongside the development of novel markers of disease will allow precision medicine to be applied to MS patients, bringing the promise of improved care. Combinations of clinical and paraclinical data are currently used for diagnosis and prognosis. The addition of advanced magnetic resonance imaging and biofluid markers has been strongly encouraged, since classifying patients according to the underlying biology will improve monitoring and treatment strategies. For example, silent progression seems to contribute significantly more than relapses to overall disability accumulation, but currently approved treatments for MS act mainly on neuroinflammation and offer only a partial protection against neurodegeneration. Further research, involving traditional and adaptive trial designs, should strive to halt, repair or protect against central nervous system damage. To personalize new treatments, their selectivity, tolerability, ease of administration, and safety must be considered, while to personalize treatment approaches, patient preferences, risk-aversion, and lifestyle must be factored in, and patient feedback used to indicate real-world treatment efficacy. The use of biosensors and machine-learning approaches to integrate biological, anatomical, and physiological parameters will take personalized medicine a step closer toward the patient's virtual twin, in which treatments can be tried before they are applied.

Advances in Neurodegenerative Diseases

Neurological disorders are the leading cause of physical and cognitive disability across the globe, currently affecting approximately 15% of the worldwide population [...].

Targeting B Cells and Microglia in Multiple Sclerosis With Bruton Tyrosine Kinase Inhibitors: A Review

Importance

Currently, disease-modifying therapies for multiple sclerosis (MS) use 4 mechanisms of action: immune modulation, suppressing immune cell proliferation, inhibiting immune cell migration, or cellular depletion. Over the last decades, the repertoire substantially increased because of the conceptual progress that not only T cells but also B cells play an important pathogenic role in MS, fostered by the empirical success of B cell-depleting antibodies against the surface molecule CD20. Notwithstanding this advance, a continuous absence of B cells may harbor safety risks, such as a decline in the endogenous production of immunoglobulins. Accordingly, novel B cell-directed MS therapies are in development, such as inhibitors targeting Bruton tyrosine kinase (BTK).

Observations

BTK is centrally involved in the B cell receptor-mediated activation of B cells, one key requirement in the development of autoreactive B cells, but also in the activation of myeloid cells, such as macrophages and microglia. Various compounds in development differ in their binding mode, selectivity and specificity, relative inhibitory concentration, and potential to enter the central nervous system. The latter may be important in assessing whether BTK inhibition is a promising strategy to control inflammatory circuits within the brain, the key process that is assumed to drive MS progression. Accordingly, clinical trials using BTK inhibitors are currently conducted in patients with relapsing-remitting MS as well as progressive MS, so far generating encouraging data regarding efficacy and safety.

Conclusions and Relevance

While the novel approach of targeting BTK is highly promising, several questions remain unanswered, such as the long-term effects of using BTK inhibitors in the treatment of inflammatory CNS disease. Potential changes in circulating antibody levels should be evaluated and compared with B cell depletion. Also important is the potential of BTK inhibitors to enter the CNS, which depends on the given compound. Remaining questions involve where BTK inhibitors fit in the landscape of MS therapeutics. A comparative analysis of their distinct properties is necessary to identify which inhibitors may be used in relapsing vs progressive forms of MS as well as to clarify which agent may be most suitable for sequential use after anti-CD20 treatment.

Prophylactic Glatiramer Acetate Treatment Positively Attenuates Spontaneous Opticospinal Encephalomyelitis

Background: Glatiramer acetate (GA) is a well-established treatment option for patients with clinically isolated syndrome and relapsing-remitting multiple sclerosis (MS) with few side effects. The double transgenic mouse model spontaneous opticospinal encephalomyelitis (OSE), based on recombinant myelin oligodendrocyte glycoprotein_35-55 reactive T and B cells, mimicks features of chronic inflammation and degeneration in MS and related disorders. Here, we investigated the effects of prophylactic GA treatment on the clinical course, histological alterations and peripheral immune cells in OSE. Objective: To investigate the effects of prophylactic glatiramer acetate (GA) treatment in a mouse model of spontaneous opticospinal encephalomyelitis (OSE). Methods: OSE mice with a postnatal age of 21 to 28 days without signs of encephalomyelitis were treated once daily either with 150 µg GA or vehicle intraperitoneally (i. p.). The animals were scored daily regarding clinical signs and weight. The animals were sacrificed after 30 days of treatment or after having reached a score of 7.0 due to animal care guidelines. We performed immunohistochemistry of spinal cord sections and flow cytometry analysis of immune cells. Results: Preventive treatment with 150 µg GA i. p. once daily significantly reduced clinical disease progression with a mean score of 3.9 ± 1.0 compared to 6.2 ± 0.7 in control animals (p < 0.01) after 30 d in accordance with positive effects on weight (p < 0.001). The immunohistochemistry showed that general inflammation, demyelination or CD11c⁺ dendritic cell infiltration did not differ. There was, however, a modest reduction of the Iba1⁺ area (p < 0.05) and F4/80⁺ area upon GA treatment (p < 0.05). The immune cell composition of secondary lymphoid organs showed a trend towards an upregulation of regulatory T cells, which lacked significance. Conclusions: Preventive treatment with GA reduces disease progression in OSE in line with modest effects on microglia/macrophages. Due to the lack of established prophylactic treatment options for chronic autoimmune diseases with a high risk of disability, our study could provide valuable indications for translational medicine.

Inhibition of CXCR2 enhances CNS remyelination via modulating PDE10A/cAMP signaling pathway

CXC chemokine receptor 2 (CXCR2) plays an important role in demyelinating diseases, but the detailed mechanisms were not yet clarified. In the present study, we mainly investigated the critical function and the potential molecular mechanisms of CXCR2 on oligodendrocyte precursor cell (OPC) differentiation and remyelination. The present study demonstrated that inhibiting CXCR2 significantly enhanced OPC differentiation and remyelination in primary cultured OPCs and ethidium bromide (EB)-intoxicated rats by facilitating the formation of myelin proteins, including PDGFRα, MBP, MAG, MOG, and Caspr. Further investigation identified phosphodiesterase 10A (PDE10A) as a main downstream protein of CXCR2, interacting with the receptor to regulate OPC differentiation, in that inhibition of CXCR2 reduced PDE10A expression while suppression of PDE10A did not affect CXCR2. Furthermore, inhibition of PDE10A promoted OPC differentiation, whereas overexpression of PDE10A down-regulated OPC differentiation. Our data also revealed that inhibition of CXCR2/PDE10A activated the cAMP/ERK1/2 signaling pathway, and up-regulated the expression of key transcription factors, including SOX10, OLIG2, MYRF, and ZFP24, that ultimately promoted remyelination and myelin protein biosynthesis. In conclusion, our findings suggested that inhibition of CXCR2 promoted OPC differentiation and enhanced remyelination by regulating PDE10A/cAMP/ERK1/2 signaling pathway. The present data also highlighted that CXCR2 may serve as a potential target for the treatment of demyelination diseases.

Neuronal deletion of MnSOD in mice leads to demyelination, inflammation and progressive paralysis that mimics phenotypes associated with progressive multiple sclerosis

Neuronal oxidative stress has been implicated in aging and neurodegenerative disease. Here we investigated the impact of elevated oxidative stress induced in mouse spinal cord by deletion of Mn-Superoxide dismutase (MnSOD) using a neuron specific Cre recombinase in Sod2 floxed mice (i-mn-Sod2 KO). Sod2 deletion in spinal cord neurons was associated with mitochondrial alterations and peroxide generation. Phenotypically, i-mn-Sod2 KO mice experienced hindlimb paralysis and clasping behavior associated with extensive demyelination and reduced nerve conduction velocity, axonal degeneration, enhanced blood brain barrier permeability, elevated inflammatory cytokines, microglia activation, infiltration of neutrophils and necroptosis in spinal cord. In contrast, spinal cord motor neuron number, innervation of neuromuscular junctions, muscle mass, and contractile function were not altered. Overall, our findings show that loss of MnSOD in spinal cord promotes a phenotype of demyelination, inflammation and progressive paralysis that mimics phenotypes associated with progressive multiple sclerosis.

Disease-modifying therapies for relapsing/active secondary progressive multiple sclerosis - a review of population-specific evidence from randomized clinical trials

Although the understanding of secondary progressive multiple sclerosis (SPMS) is evolving, early detection of relapse-independent progression remains difficult. This is further complicated by superimposed relapses and compensatory mechanisms that allow for silent progression. The term relapsing multiple sclerosis (RMS) subsumes relapsing-remitting multiple sclerosis (RRMS) and SPMS with relapses. The latter is termed 'active' SPMS, for which disease-modifying therapies (DMTs) approved for either RMS or active SPMS can be used. However, the level of evidence supporting efficacy and safety in SPMS differs between drugs approved for RMS and SPMS. Our review aims to identify current evidence from published clinical trials and European public assessment reports from the marketing authorization procedure on the efficacy, especially on progression, of DMTs approved for RMS and SPMS. To identify relevant evidence, a literature search has been conducted and European public assessment reports of DMTs approved for RMS have been screened for unpublished data specific to SPMS. Only two clinical trials demonstrated a significant reduction in disability progression in SPMS study populations: the EXPAND study for siponimod, which included a typical SPMS population, and the European study for interferon (IFN)-beta 1b s.c., which included patients with very early and active SPMS. Both DMTs also achieved significant reductions in relapse rates. Ocrelizumab, cladribine, ofatumumab, and ponesimod are all approved for RMS - ocrelizumab, ofatumumab, and ponesimod based on an RMS study, cladribine based on an RRMS study. Data on efficacy in SPMS are only available from post hoc analyses of very small subgroups, representing only up to 15% of the total study population. For these DMTs, approval for RMS, including active SPMS, was mainly based on the assumption that the reduction in relapse rate observed in patients with RRMS can also be applied to SPMS. Based on that, the potential of these drugs to reduce relapse-independent progression remains unclear.