Thinking outside the box: non-canonical targets in multiple sclerosis

Modeling and simulation for prediction of multiple sclerosis progression

In light of extensive work that has created a wide range of techniques for predicting the course of multiple sclerosis (MS) disease, this paper attempts to provide an overview of these approaches and put forth an alternative way to predict the disease progression. For this purpose, the existing methods for estimating and predicting the course of the disease have been categorized into clinical, radiological, biological, and computational or artificial intelligence-based markers. Weighing the weaknesses and strengths of these prognostic groups is a profound method that is yet in need and works directly at the level of diseased connectivity. Therefore, we propose using the computational models in combination with established connectomes as a predictive tool for MS disease trajectories. The fundamental conduction-based Hodgkin-Huxley model emerged as promising from examining these studies. The advantage of the Hodgkin-Huxley model is that certain properties of connectomes, such as neuronal connection weights, spatial distances, and adjustments of signal transmission rates, can be taken into account. It is precisely these properties that are particularly altered in MS and that have strong implications for processing, transmission, and interactions of neuronal signaling patterns. The Hodgkin-Huxley (HH) equations as a point-neuron model are used for signal propagation inside a small network. The objective is to change the conduction parameter of the neuron model, replicate the changes in myelin properties in MS and observe the dynamics of the signal propagation across the network. The model is initially validated for different lengths, conduction values, and connection weights through three nodal connections. Later, these individual factors are incorporated into a small network and simulated to mimic the condition of MS. The signal propagation pattern is observed after inducing changes in conduction parameters at certain nodes in the network and compared against a control model pattern obtained before the changes are applied to the network. The signal propagation pattern varies as expected by adapting to the input conditions. Similarly, when the model is applied to a connectome, the pattern changes could give an insight into disease progression. This approach has opened up a new path to explore the progression of the disease in MS. The work is in its preliminary state, but with a future vision to apply this method in a connectome, providing a better clinical tool.

Rim lesions in MS at 3T: clinical correlation and possible radiological alternatives for daily practice at lower field strength

BACKGROUND AND PURPOSE

Paramagnetic rim lesions (PRLs) have been described as an imaging feature specific to multiple sclerosis (MS) using high-field strength phase-sensitive MR imaging. These lesions are suggested to reflect chronic active inflammation associated with greater disease severity and a more rapid disability progression. The aim of our study is to investigate the relationship between PRLs, clinical parameters, other radiological findings and disease progression.

MATERIAL AND METHODS

This cross-sectional study included MS patients treated with teriflunomide, fingolimod, natalizumab or ocrelizumab for at least 2 years. PRLs seen at 3T MRI were analysed and correlated with clinical data and radiological progression, defined as an increase of the T2/FLAIR-lesion load during therapy. In the search for alternatives for these PRLs, we defined two additional radiological markers: 'FLAIR-bullet lesions', and on post-contrast black-blood (BB) images, 'BB-bullet lesions'.

RESULTS

We included 84 MS patients of whom 27 (32 %) had at least 1 PRL. PRLs were associated with radiological progression under therapy (p=0.039) and higher clinical disability scores, although only significant for 9-Hole Peg Test (p=0.023). Patients with FLAIR-bullet or BB-bullet lesions at 3T MRI had a higher chance of PRL (p<0.001) with a likelihood ratio of 13.2 for FLAIR-bullets and 12.6 for BB-bullet lesions, thanks to the high negative predictive value of respectively 83 % and 90 %.

CONCLUSION

PRLs are associated with an increase of T2/FLAIR-lesion load under therapy and unfavourable clinical outcome. Our newly defined 'bullet lesions' are associated with PRLs and might be an interesting MRI marker for centres without access to high-field SWI images.

Age-related decline in cerebral oxygen consumption in multiple sclerosis

Cerebral oxygen metabolism is altered in relapsing-remitting multiple sclerosis (RRMS), possibly a result of disease related cerebral atrophy with subsequent decreased oxygen demand. However, MS inflammation can also inhibit brain metabolism. Therefore, we measured cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) using MRI phase contrast mapping and susceptibility-based oximetry in 44 patients with early RRMS and 36 healthy controls. Cerebral atrophy and white matter lesion load were assessed from high-resolution structural MRI. Expanded Disability Status Scale (EDSS) scores were collected from medical records. The CMRO2 was significantly lower in patients (-15%, p = 0.002) and decreased significantly with age in patients relative to the controls (-1.35 µmol/100 g/min/year, p = 0.036). The lower CMRO2 in RRMS was primarily driven by a higher venous oxygen saturation in the sagittal sinus (p = 0.007) and not a reduction in CBF (p = 0.69). There was no difference in cerebral atrophy between the groups, and no correlation between CMRO2 and MS lesion volume or EDSS score. Therefore, the progressive CMRO2 decline observed before the occurrence of significant cerebral atrophy and despite adequate CBF supports emerging evidence of dysfunctional cellular respiration as a potential pathogenic mechanism and therapeutic target in RRMS.

The neuropathobiology of multiple sclerosis

Chronic low-grade inflammation and neuronal deregulation are two components of a smoldering disease activity that drives the progression of disability in people with multiple sclerosis (MS). Although several therapies exist to dampen the acute inflammation that drives MS relapses, therapeutic options to halt chronic disability progression are a major unmet clinical need. The development of such therapies is hindered by our limited understanding of the neuron-intrinsic determinants of resilience or vulnerability to inflammation. In this Review, we provide a neuron-centric overview of recent advances in deciphering neuronal response patterns that drive the pathology of MS. We describe the inflammatory CNS environment that initiates neurotoxicity by imposing ion imbalance, excitotoxicity and oxidative stress, and by direct neuro-immune interactions, which collectively lead to mitochondrial dysfunction and epigenetic dysregulation. The neuronal demise is further amplified by breakdown of neuronal transport, accumulation of cytosolic proteins and activation of cell death pathways. Continuous neuronal damage perpetuates CNS inflammation by activating surrounding glia cells and by directly exerting toxicity on neighbouring neurons. Further, we explore strategies to overcome neuronal deregulation in MS and compile a selection of neuronal actuators shown to impact neurodegeneration in preclinical studies. We conclude by discussing the therapeutic potential of targeting such neuronal actuators in MS, including some that have already been tested in interventional clinical trials.

A new class of 7-deazaguanine agents targeting autoimmune diseases: dramatic reduction of synovial fibroblast IL-6 production from human rheumatoid arthritis patients and improved performance against murine experimental autoimmune encephalomyelitis

A simple in vitro assay involving the measurement of IL-6 production in human synovial fibroblasts from rheumatoid arthritis patients has been utilised to select candidates from a targeted library of queuine tRNA ribosyltransferase (QTRT) substrates for subsequent in vivo screening in murine experimental autoimmune encephalomyelitis (EAE - a model of multiple sclerosis). The in vitro activity assay discriminated between poor and excellent 7-deazaguanine QTRT substrates and allowed the identification of several structures which subsequently outperformed the previous lead in EAE. Two molecules were of significant promise: one rigidified analogue of the lead, and another considerably simpler structure incorporating an oxime motif which differs structurally from the lead to a considerable extent. These studies provide data from human cells for the first time and have expanded both the chemical space and current understanding of the structure-activity relationship underpinning the remarkable potential of 7-deazguanines in a Multiple Sclerosis disease model.

Combined in vivo effect of N-acylethanolamine-hydrolyzing acid amidase and glycogen synthase kinase-3β inhibition to treat multiple sclerosis

The current pharmacological approaches to multiple sclerosis (MS) target its inflammatory and autoimmune components, but effective treatments to foster remyelination and axonal repair are still lacking. We therefore selected two targets known to be involved in MS pathogenesis: N-acylethanolamine-hydrolyzing acid amidase (NAAA) and glycogen synthase kinase-3β (GSK-3β). We tested whether inhibiting these targets exerted a therapeutic effect against experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The combined inhibition of NAAA and GSK-3β by two selected small-molecule compounds, ARN16186 (an NAAA inhibitor) and AF3581 (a GSK-3β inhibitor), effectively mitigated disease progression, rescuing the animals from paralysis and preventing a worsening of the pathology. The complementary activity of the two inhibitors reduced the infiltration of immune cells into the spinal cord and led to the formation of thin myelin sheaths around the axons post-demyelination. Specifically, the inhibition of NAAA and GSK-3β modulated the over-activation of NF-kB and STAT3 transcription factors in the EAE-affected mice and induced the nuclear translocation of β-catenin, reducing the inflammatory insult and promoting the remyelination process. Overall, this work demonstrates that the dual-targeting of key aspects responsible for MS progression could be an innovative pharmacological approach to tackle the pathology.

Comparative effectiveness of dimethyl fumarate versus non-specific immunosuppressants: Real-world evidence from MSBase

Background

The use of non-specific immunosuppressants (NSIS) to treat multiple sclerosis (MS) remains prevalent in certain geographies despite safety concerns, likely due to resource limitations.

Objective

To use MSBase registry data to compare real-world outcomes in adults with relapsing-remitting MS (RRMS) treated with dimethyl fumarate (DMF) or NSIS (azathioprine, cyclosporine, cyclophosphamide, methotrexate, mitoxantrone or mycophenolate mofetil) between January 1, 2014 and April 1, 2022.

Methods

Treatment outcomes were compared using inverse probability of treatment weighting (IPTW) Cox regression. Outcomes were annualized relapse rates (ARRs), time to discontinuation, time to first relapse (TTFR) and time to 24-week confirmed disability progression (CDP) or 24-week confirmed disability improvement (CDI; in patients with baseline Expanded Disability Status Scale [EDSS] score ≥2).

Results

After IPTW, ARR was similar for DMF (0.13) and NSIS (0.16; p = 0.29). There was no difference in TTFR between cohorts (hazard ratio [HR]: 0.98; p = 0.84). The DMF cohort experienced longer times to discontinuation (HR: 0.75; p = 0.001) and CDP (HR: 0.53; p = 0.001), and shorter time to CDI (HR: 1.99; p < 0.008), versus the NSIS cohort.

Conclusion

This analysis supports the use of DMF to treat patients with relapsing forms of MS, and may have implications for MS practices in countries where NSIS are commonly used to treat RRMS.

Neuroprotective effect of curcumin against experimental autoimmune encephalomyelitis-induced cognitive and physical impairments in mice: an insight into the role of the AMPK/SIRT1 pathway

Multiple sclerosis (MS) is an incurable chronic neurodegenerative disease where autoimmunity, oxidative stress, and neuroinflammation collaboration predispose myelin sheath destruction. Interestingly, curcumin, a natural polyphenol, showed a neuroprotective effect in numerous neurodegenerative diseases, including MS. Nevertheless, the influence of curcumin against MS-induced cognitive impairment is still vague. Hence, we induced experimental autoimmune encephalomyelitis (EAE) in mice using spinal cord homogenate (SCH) and complete Freund's adjuvant, which eventually mimic MS. This study aimed not only to evaluate curcumin efficacy against EAE-induced cognitive and motor dysfunction, but also to explore a novel mechanism of action, by which curcumin exerts its beneficial effects in MS. Curcumin (200 mg/kg/day) efficacy was evaluated by behavioral tests, histopathological examination, and biochemical tests. Concisely, curcumin amended EAE-induced cognitive and motor impairments, as demonstrated by the behavioral tests and histopathological examination of the hippocampus. Interestingly, curcumin activated the adenosine monophosphate (AMP)-activated protein kinase/silent mating type information regulation 2 homolog 1 (AMPK/SIRT1) axis, which triggered cyclic AMP response element-binding protein/brain-derived neurotrophic factor/myelin basic protein (CREB/BDNF/MBP) pathway, hindering demyelination of the corpus callosum. Furthermore, AMPK/SIRT1 activation augmented nuclear factor erythroid 2-related factor 2 (Nrf2), a powerful antioxidant, amending EAE-induced oxidative stress. Additionally, curcumin abolished EAE-induced neuroinflammation by inhibiting Janus kinase 2 /signal transducers and activators of transcription 3 (JAK2/STAT3) axis, by various pathways, including AMPK/SIRT1 activation. JAK2/STAT3 inhibition halts inflammatory cytokines synthesis. In conclusion, curcumin's neuroprotective effect in EAE is controlled, at least in part, by AMPK/SIRT1 activation, which ultimately minimizes EAE-induced neuronal demyelination, oxidative stress, and neuroinflammation.

Inhibiting the NLRP3 Inflammasome with MCC950 Alleviates Neurological Impairment in the Brain of EAE Mice

Multiple sclerosis (MS) is a chronic disease that is characterized by demyelination and neuronal damage. Experimental autoimmune encephalomyelitis (EAE) mice are used to model the disease progression of MS and mirror MS-like pathology. Previous researches have confirmed that inhibition of NLRP3 inflammasome significantly alleviated the severity of EAE mice and the demyelination of spinal cord, but its effect on neuronal damage and oligodendrocyte loss in the brain remains unclear. In this study, female C57BL/6 mice were immunized with MOG35-55 and PTX to establish experimental autoimmune encephalomyelitis (EAE) model. MCC950, a selective NLRP3 inflammasome inhibitor, was used to investigate the effect of NLRP3 inflammasome on the pathological changes and glial cell activation in the brain of EAE mice by immunohistochemistry. Our results demonstrated that MCC950 ameliorated the neuronal damage, demyelination, and oligodendrocyte loss in the brain of EAE mice. This protective effect of MCC950 may be attributed to its ability to suppress the activation of glial cells and prevents microglia polarization to M1 phenotype. Our work indicates that inhibition of NLRP3 inflammasome has the therapeutic effects of neuroprotection through immunomodulation and is a promising therapeutic strategy for MS.

Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases

The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.

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.

Immunoswitch Nanomodulators Enable Active Targeting and Selective Proliferation of Regulatory T Cells for Multiple Sclerosis Therapy

Interleukin-2 (IL-2) used in multiple sclerosis (MS) therapy modulates the balance between regulatory T (Treg) cells and effector T (Teff) cells. However, the off-target activation of Teff cells by IL-2 limits its clinical application. Therefore, a rapidly prepared immunoswitch nanomodulator termed aT-IL2C NPs was developed, which specifically recognized Treg cells with high TIGIT expression thanks to the presence of an anti-TIGIT and an IL-2/JES6-1 complex (IL2C) being delivered to Treg cells but not to Teff cells with low TIGIT expression. Then, IL2C released IL-2 due to the specific expression of the high-affinity IL-2 receptor on Treg cells, thus enabling the active targeting and selective proliferation of Treg cells. Moreover, the anti-TIGIT of aT-IL2C NPs selectively inhibited the proliferation of Teff cells while leaving the proliferation of Treg cells unaffected. In addition, since the IL-2 receptor on Teff cells had medium-affinity, the IL2C hardly released IL-2 to Teff cells, thus enabling the inhibition of Teff cell proliferation. The treatment of experimental autoimmune encephalomyelitis (EAE) mice with aT-IL2C NPs ameliorated the severity of the EAE and restored white matter integrity. Collectively, this work described a potential promising agent for effective MS therapy.

Assessing neuroprotective effects of diroximel fumarate and siponimod via modulation of pacemaker channels in an experimental model of remyelination

Cuprizone (CPZ)-induced alterations in axonal myelination are associated with a period of neuronal hyperexcitability and increased activity of hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels in the thalamocortical (TC) system. Substances used for the treatment of multiple sclerosis (MS) have been shown to normalize neuronal excitability in CPZ-treated mice. Therefore, we aimed to examine the effects of diroximel fumarate (DRF) and the sphingosine 1-phospate receptor (S1PR) modulator siponimod on action potential firing and the inward current (Ih) carried by HCN ion channels in naive conditions and during different stages of de- and remyelination. Here, DRF application reduced Ih current density in ex vivo patch clamp recordings from TC neurons of the ventrobasal thalamic complex (VB), thereby counteracting the increase of Ih during early remyelination. Siponimod reduced Ih in VB neurons under control conditions but had no effect in neurons of the auditory cortex (AU). Furthermore, siponimod increased and decreased AP firing properties of neurons in VB and AU, respectively. Computational modeling revealed that both DRF and siponimod influenced thalamic bursting during early remyelination by delaying the onset and decreasing the interburst frequency. Thus, substances used in MS treatment normalize excitability in the TC system by influencing AP firing and Ih.

Efficacy of a benzothiazole-based LRRK2 inhibitor in oligodendrocyte precursor cells and in a murine model of multiple sclerosis

AIMS

Multiple sclerosis (MS) is a chronic neurological disease that currently lacks effective curative treatments. There is a need to find effective therapies, especially to reverse the progressive demyelination and neuronal damage. Oligodendrocytes form the myelin sheath around axons in the central nervous system (CNS) and oligodendrocyte precursor cells (OPCs) undergo mechanisms that enable spontaneously the partial repair of damaged lesions. The aim of this study was to discover small molecules with potential effects in demyelinating diseases, including (re)myelinating properties.

METHODS

Recently, it has been shown how LRRK2 inhibition promotes oligodendrogliogenesis and therefore an efficient repair or myelin damaged lesions. Here we explored small molecules inhibiting LRRK2 as potential enhancers of primary OPCs proliferation and differentiation, and their potential impact on the clinical score of experimental autoimmune encephalomyelitys (EAE) mice, a validated model of the most frequent clinical form of MS, relapsing-remitting MS.

RESULTS

One of the LRRK2 inhibitors presented in this study promoted the proliferation and differentiation of OPC primary cultures. When tested in the EAE murine model of MS, it exerted a statistically significant reduction of the clinical burden of the animals, and histological evidence revealed how the treated animals presented a reduced lesion area in the spinal cord.

CONCLUSIONS

For the first time, a small molecule with LRRK2 inhibition properties presented (re)myelinating properties in primary OPCs cultures and potentially in the in vivo murine model. This study provides an in vivo proof of concept for a LRRK2 inhibitor, confirming its potential for the treatment of MS.

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.

Bioavailable central nervous system disease-modifying therapies for multiple sclerosis

Disease-modifying therapies for relapsing multiple sclerosis reduce relapse rates by suppressing peripheral immune cells but have limited efficacy in progressive forms of the disease where cells in the central nervous system play a critical role. To our knowledge, alemtuzumab, fumarates (dimethyl, diroximel, and monomethyl), glatiramer acetates, interferons, mitoxantrone, natalizumab, ocrelizumab, ofatumumab, and teriflunomide are either limited to the periphery or insufficiently studied to confirm direct central nervous system effects in participants with multiple sclerosis. In contrast, cladribine and sphingosine 1-phosphate receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are central nervous system-penetrant and could have beneficial direct central nervous system properties.

Global, regional, and national incidence of six major immune-mediated inflammatory diseases: findings from the global burden of disease study 2019

Background

The causes for immune-mediated inflammatory diseases (IMIDs) are diverse and the incidence trends of IMIDs from specific causes are rarely studied. The study aims to investigate the pattern and trend of IMIDs from 1990 to 2019.

Methods

We collected detailed information on six major causes of IMIDs, including asthma, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, psoriasis, and atopic dermatitis, between 1990 and 2019, derived from the Global Burden of Disease study in 2019. The average annual percent change (AAPC) in number of incidents and age standardized incidence rate (ASR) on IMIDs, by sex, age, region, and causes, were calculated to quantify the temporal trends.

Findings

In 2019, rheumatoid arthritis, atopic dermatitis, asthma, multiple sclerosis, psoriasis, inflammatory bowel disease accounted 1.59%, 36.17%, 54.71%, 0.09%, 6.84%, 0.60% of overall new IMIDs cases, respectively. The ASR of IMIDs showed substantial regional and global variation with the highest in High SDI region, High-income North America, and United States of America. Throughout human lifespan, the age distribution of incident cases from six IMIDs was quite different. Globally, incident cases of IMIDs increased with an AAPC of 0.68 and the ASR decreased with an AAPC of -0.34 from 1990 to 2019. The incident cases increased across six IMIDs, the ASR of rheumatoid arthritis increased (0.21, 95% CI 0.18, 0.25), while the ASR of asthma (AAPC = -0.41), inflammatory bowel disease (AAPC = -0.72), multiple sclerosis (AAPC = -0.26), psoriasis (AAPC = -0.77), and atopic dermatitis (AAPC = -0.15) decreased. The ASR of overall and six individual IMID increased with SDI at regional and global level. Countries with higher ASR in 1990 experienced a more rapid decrease in ASR.

Interpretation

The incidence patterns of IMIDs varied considerably across the world. Innovative prevention and integrative management strategy are urgently needed to mitigate the increasing ASR of rheumatoid arthritis and upsurging new cases of other five IMIDs, respectively.

Funding

The Global Burden of Disease Study is funded by the Bill and Melinda Gates Foundation. The project funded by Scientific Research Fund of Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital (2022QN38).

Brain and immune system-derived extracellular vesicles mediate regulation of complement system, extracellular matrix remodeling, brain repair and antigen tolerance in Multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated central nervous system disease whose course is unpredictable. Finding biomarkers that help to better comprehend the disease's pathogenesis is crucial for supporting clinical decision-making. Blood extracellular vesicles (EVs) are membrane-bound particles secreted by all cell types that contain information on the disease's pathological processes.

PURPOSE

To identify the immune and nervous system-derived EV profile from blood that could have a specific role as biomarker in MS and assess its possible correlation with disease state.

RESULTS

Higher levels of T cell-derived EVs and smaller size of neuron-derived EVs were associated with clinical relapse. The smaller size of the oligodendrocyte-derived EVs was related with motor and cognitive impairment. The proteomic analysis identified mannose-binding lectin serine protease 1 and complement factor H from immune system cell-derived EVs as autoimmune disease-associated proteins. We observed hepatocyte growth factor-like protein in EVs from T cells and inter-alpha-trypsin inhibitor heavy chain 2 from neurons as white matter injury-related proteins. In patients with MS, a specific protein profile was found in the EVs, higher levels of alpha-1-microglobulin and fibrinogen β chain, lower levels of C1S and gelsolin in the immune system-released vesicles, and Talin-1 overexpression in oligodendrocyte EVs. These specific MS-associated proteins, as well as myelin basic protein in oligodendrocyte EVs, correlated with disease activity in the patients with MS.

CONCLUSION

Neural-derived and immune-derived EVs found in blood appear to be good specific biomarkers in MS for reflecting the disease state.

Linking Mechanisms of Vitamin D Signaling with Multiple Sclerosis

Environmental triggers often work via signal transduction cascades that modulate the epigenome and transcriptome of cell types involved in the disease process. Multiple sclerosis (MS) is an autoimmune disease affecting the central nervous system being characterized by a combination of recurring inflammation, demyelination and progressive loss of axons. The mechanisms of MS onset are not fully understood and genetic variants may explain only some 20% of the disease susceptibility. From the environmental factors being involved in disease development low vitamin D levels have been shown to significantly contribute to MS susceptibility. The pro-hormone vitamin D3 acts via its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) as a high affinity ligand to the transcription factor VDR (vitamin D receptor) and is a potent modulator of the epigenome at thousands of genomic regions and the transcriptome of hundreds of genes. A major target tissue of the effects of 1,25(OH)2D3 and VDR are cells of innate and adaptive immunity, such as monocytes, dendritic cells as well as B and T cells. Vitamin D induces immunological tolerance in T cells and reduces inflammatory reactions of various types of immune cells, all of which are implicated in MS pathogenesis. The immunomodulatory effects of 1,25(OH)2D3 contribute to the prevention of MS. However, the strength of the responses to vitamin D3 supplementation is highly variegated between individuals. This review will relate mechanisms of individual's vitamin D responsiveness to MS susceptibility and discuss the prospect of vitamin D3 supplementation as a way to extinguish the autoimmunity in 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.

Queuine Analogues Incorporating the 7-Aminomethyl-7-deazaguanine Core: Structure-Activity Relationships in the Treatment of Experimental Autoimmune Encephalomyelitis

A library of queuine analogues targeting the modification of tRNA isoacceptors for Asp, Asn, His and Tyr catalysed by queuine tRNA ribosyltransferase (QTRT, also known as TGT) was evaluated in the treatment of a chronic multiple sclerosis model: murine experimental autoimmune encephalomyelitis. Several active 7-deazaguanines emerged, together with a structure-activity relationship involving the necessity for a flexible alkyl chain of fixed length.

Nanopore sequencing identifies differentially methylated genes in the central nervous system in experimental autoimmune encephalomyelitis

Multiple Sclerosis (MS) is a chronic autoimmune-mediated demyelinating disease of the central nervous system (CNS) that might be triggered by aberrant epigenetic changes in the genome. DNA methylation is the most studied epigenetic mechanism that participates in MS pathogenesis. However, the overall methylation level in the CNS of MS patients remains elusive. We used direct long-read nanopore DNA sequencing and characterized the differentially methylated genes in the brain from mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We identified 163 hypomethylated promoters and 327 hypermethylated promoters. These genomic alterations were linked to various biological processes including metabolism, immune responses, neural activities, and mitochondrial dynamics, all of which are vital for EAE development. Our results indicate a great potential of nanopore sequencing in identifying genomic DNA methylation in EAE and provide important guidance for future studies investigating the MS/EAE pathology.

Dual role of peripheral B cells in multiple sclerosis: emerging remote players in demyelination and novel diagnostic biomarkers

Introduction

Multiple sclerosis is an inflammatory and demyelinating disease caused by a pathogenic immune response against the myelin sheath surfaces of oligodendrocytes. The demyelination has been classically associated with pathogenic B cells residing in the central nervous system that release autoreactive antibodies against myelin. The aim of the present study was to investigate whether extracellular vesicles (EVs) mediate delivery of myelin autoreactive antibodies from peripheral B cells against oligodendrocytes in multiple sclerosis (MS) and to analyze whether these EVs could mediate demyelination in vitro. We also studied the role of these EV-derived myelin antibodies as a diagnostic biomarker in MS.

Methods

This is a prospective, observational, and single-center study that includes patients with MS and two control groups: patients with non-immune white matter lesions and healthy controls. We isolated B-cell-derived EVs from the blood and cerebrospinal fluid (CSF) and analyzed their myelin antibody content. We also studied whether antibody-loaded EVs reach oligodendrocytes in patients with MS and the effect on demyelination of B-cell-derived EVs containing antibodies in vitro.

Results

This study enrolled 136 MS patients, 23 white matter lesions controls, and 39 healthy controls. We found autoreactive myelin antibodies in EVs that were released by peripheral B cells, but not by populations of B cells resident in CSF. We also identified a cut-off of 3.95 ng/mL of myelin basic protein autoantibodies in EVs from peripheral B cells, with 95.2% sensitivity and 88.2% specificity, which allows us to differentiate MS patients from healthy controls. EV-derived myelin antibodies were also detected in the oligodendrocytes of MS patients. Myelin antibody-loaded EVs from B cells induced myelin markers decrease of oligodendrocytes in vitro.

Discussion

Peripheral reactive immune cells could contribute remotely to MS pathogenesis by delivering myelin antibodies to oligodendrocytes. EV-derived myelin antibodies could play a role as diagnostic biomarker in MS.

The prevalence of IgG antibodies against milk and milk antigens in patients with multiple sclerosis

Introduction

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS). The pathophysiology of MS is complex and is said to be influenced by multiple environmental determinants, including diet. We and others have previously demonstrated how consumption of bovine milk can aggravate disease severity in MS patients, which can be explained by molecular mimicry between milk antigens and those expressed within the CNS. In this study we set out to identify alternatives to drinking cow milk which might be less detrimental to MS patients who have a genetic predisposition towards developing antibody titers against bovine milk antigens that cross-react with CNS antigens.

Methods

To this end, we screened 35 patients with MS and 20 healthy controls for their IgG reactivity against an array of animal-sourced milk, plant-based alternatives as well as individual antigens from bovine milk.

Results

We demonstrate that MS patients have a significantly higher IgG response to animal-sourced milk, especially cow milk, in comparison to healthy donors. We also show that the reactivity to cow milk in MS patients can be attributed to reactivity against different bovine milk antigens. Finally, our correlation data indicate the co-existence of antibodies to individual bovine milk antigens and their corresponding cross-reactive CNS antigens.

Discussion

Taken together, we suggest screening of blood from MS patients for antibodies against different types of milk and milk antigens in order to establish a personalized diet regimen.

Multiple Sclerosis-Related Dietary and Nutritional Issues: An Updated Scoping Review with a Focus on Pediatrics

PURPOSE

Lifestyle/dietetic habits play an important role in the development and progression of multiple sclerosis (MS) disease. Here, we examine the basic pathomechanisms underlying intestinal and brain barrier modifications in MS and consider diets and dietary supplementations proposed over time to complement pharmacological therapies for improving disease outcome both in adults and in children.

METHODS

Scoping literature search about evidence-based findings in MS-related gut-brain axis (GBA) pathophysiology and nutritional issues at all ages.

FINDINGS

Data show that (1) no universal best diet exists, (2) healthy/balanced diets are, however, necessary to safeguard the adequate intake of all essential nutrients, (3) diets with high intakes of fruits, vegetables, whole grains, and lean proteins that limit processed foods, sugar, and saturated fat appear beneficial for their antioxidant and anti-inflammatory properties and their ability to shape a gut microbiota that respects the gut and brain barriers, (4) obesity may trigger MS onset and/or its less favorable course, especially in pediatric-onset MS. Vitamin D and polyunsaturated fatty acids are the most studied supplements for reducing MS-associated inflammation.

CONCLUSIONS

Pending results from other and/or newer approaches targeting the GBA (e.g., pre- and probiotics, engineered probiotics, fecal-microbiota transplantation), accurate counseling in choosing adequate diet and maintaining physical activity remains recommended for MS prevention and management both in adults and children.

It takes two to remyelinate: A bioengineered platform to study astrocyte-oligodendrocyte crosstalk and potential therapeutic targets in remyelination

The loss of the myelin sheath insulating axons is the hallmark of demyelinating diseases. These pathologies often lead to irreversible neurological impairment and patient disability. No effective therapies are currently available to promote remyelination. Several elements contribute to the inadequacy of remyelination, thus understanding the intricacies of the cellular and signaling microenvironment of the remyelination niche might help us to devise better strategies to enhance remyelination. Here, using a new in vitro rapid myelinating artificial axon system based on engineered microfibres, we investigated how reactive astrocytes influence oligodendrocyte (OL) differentiation and myelination ability. This artificial axon culture system enables the effective uncoupling of molecular cues from the biophysical properties of the axons, allowing the detailed study of the astrocyte-OL crosstalk. Oligodendrocyte precursor cells (OPCs) were cultured on poly(trimethylene carbonate-co-ε-caprolactone) copolymer electrospun microfibres that served as surrogate axons. This platform was then combined with a previously established tissue engineered glial scar model of astrocytes embedded in 1 % (w/v) alginate matrices, in which astrocyte reactive phenotype was acquired using meningeal fibroblast conditioned medium. OPCs were shown to adhere to uncoated engineered microfibres and differentiate into myelinating OL. Reactive astrocytes were found to significantly impair OL differentiation ability, after six and eight days in a co-culture system. Differentiation impairment was seen to be correlated with astrocytic miRNA release through exosomes. We found significantly reduction on the expression of pro-myelinating miRNAs (miR-219 and miR-338) and an increase in anti-myelinating miRNA (miR-125a-3p) content between reactive and quiescent astrocytes. Additionally, we show that OPC differentiation inhibition could be reverted by rescuing the activated astrocytic phenotype with ibuprofen, a chemical inhibitor of the small rhoGTPase RhoA. Overall, these findings show that modulating astrocytic function might be an interesting therapeutic avenue for demyelinating diseases. The use of these engineered microfibres as an artificial axon culture system will enable the screening for potential therapeutic agents that promote OL differentiation and myelination while providing valuable insight on the myelination/remyelination processes.

Influence of inflammatory processes on thalamocortical activity

It is known that the thalamus plays an important role in pathological brain conditions involved in demyelinating, inflammatory and neurodegenerative diseases such as Multiple Sclerosis (MS). Beside immune cells and cytokines, ion channels were found to be key players in neuroinflammation. MS is a prototypical example of an autoimmune disease of the central nervous system that is classified as a channelopathy where abnormal ion channel function leads to symptoms and clinical signs. Here we review the influence of the cytokine-ion channel interaction in the thalamocortical system in demyelination and inflammation.

The role of iron metabolism in the pathogenesis and treatment of multiple sclerosis

Multiple sclerosis is a severe demyelinating disease mediated by cells of the innate and adaptive immune system, especially pathogenic T lymphocytes that produce the pro-inflammatory cytokine granulocyte-macrophage colony stimulating factor (GM-CSF). Although the factors and molecules that drive the genesis of these cells are not completely known, some were discovered and shown to promote the development of such cells, such as dietary factors. In this regard, iron, the most abundant chemical element on Earth, has been implicated in the development of pathogenic T lymphocytes and in MS development via its effects on neurons and glia. Therefore, the aim of this paper is to revise the state-of-art regarding the role of iron metabolism in cells of key importance to MS pathophysiology, such as pathogenic CD4+ T cells and CNS resident cells. Harnessing the knowledge of iron metabolism may aid in the discovery of new molecular targets and in the development of new drugs that tackle MS and other diseases that share similar pathophysiology.

B cell targeted therapies in inflammatory autoimmune disease of the central nervous system

Cumulative evidence along several lines indicates that B cells play an important role in the pathological course of multiple sclerosis (MS), neuromyelitisoptica spectrum disorders (NMOSD) and related CNS diseases. This has prompted extensive research in exploring the utility of targeting B cells to contain disease activity in these disorders. In this review, we first recapitulate the development of B cells from their origin in the bone marrow to their migration to the periphery, including the expression of therapy-relevant surface immunoglobulin isotypes. Not only the ability of B cells to produce cytokines and immunoglobulins seems to be essential in driving neuroinflammation, but also their regulatory functions strongly impact pathobiology. We then critically assess studies of B cell depleting therapies, including CD20 and CD19 targeting monoclonal antibodies, as well as the new class of B cell modulating substances, Bruton´s tyrosinekinase (BTK) inhibitors, in MS, NMOSD and MOGAD.

Glia Connect Inflammation and Neurodegeneration in Multiple Sclerosis

Multiple sclerosis (MS) is regarded as a chronic inflammatory disease that leads to demyelination and eventually to neurodegeneration. Activation of innate immune cells and other inflammatory cells in the brain and spinal cord of people with MS has been well described. However, with the innovation of technology in glial cell research, we have a deep understanding of the mechanisms of glial cells connecting inflammation and neurodegeneration in MS. In this review, we focus on the role of glial cells, including microglia, astrocytes, and oligodendrocytes, in the pathogenesis of MS. We mainly focus on the connection between glial cells and immune cells in the process of axonal damage and demyelinating neuron loss.

Glia Connect Inflammation and Neurodegeneration in Multiple Sclerosis

Multiple sclerosis (MS) is regarded as a chronic inflammatory disease that leads to demyelination and eventually to neurodegeneration. Activation of innate immune cells and other inflammatory cells in the brain and spinal cord of people with MS has been well described. However, with the innovation of technology in glial cell research, we have a deep understanding of the mechanisms of glial cells connecting inflammation and neurodegeneration in MS. In this review, we focus on the role of glial cells, including microglia, astrocytes, and oligodendrocytes, in the pathogenesis of MS. We mainly focus on the connection between glial cells and immune cells in the process of axonal damage and demyelinating neuron loss.

Driving time-based identification of gaps in specialised care coverage: An example of neuroinflammatory diseases in Germany

Objective

Due to the growing complexity in monitoring and treatment of many disorders, disease-specific care and research networks offer patients certified healthcare. However, the networks' ability to provide health services close to patients' homes usually remains vague. Digital Health Technologies (DHTs) help to provide better care, especially if implemented in a targeted manner in regions undersupplied by specialised networks. Therefore, we used a car travel time-based isochrone approach to identify care gaps using the example of the neuroinflammation-focused German healthcare and research networks for multiple sclerosis (MS), myasthenia gravis (MG), myositis and immune-mediated neuropathy.

Methods

Excellence centres were mapped, and isochrones for 30, 60, 90 and 120 minutes were calculated. The resulting geometric figures were aggregated and used to mask the global human settlement population grid 2019 to estimate German inhabitants that can reach centres within the given periods.

Results

While 96.48% of Germans can drive to an MS-focused centre within one hour, coverage is lower for the rare disease networks for MG (48.3%), myositis (43.1%) and immune-mediated neuropathy (56.7%). Within 120 minutes, more than 80% of Germans can reach a centre of any network. Besides the generally worse covered rural regions such as North-Eastern Germany, the rare disease networks also show network-specific regional underrepresentation.

Conclusion

An isochrone-based approach helps identify regions where specialised care is hard to reach, which might be especially troublesome in the case of an often disabled patient collective. Patient care could be improved by focusing deployments of disease-specific DHTs on these areas.

The neuroimmune axis of Alzheimer's disease

Alzheimer's disease (AD) is a genetically complex and heterogeneous disorder with multifaceted neuropathological features, including β-amyloid plaques, neurofibrillary tangles, and neuroinflammation. Over the past decade, emerging evidence has implicated both beneficial and pathological roles for innate immune genes and immune cells, including peripheral immune cells such as T cells, which can infiltrate the brain and either ameliorate or exacerbate AD neuropathogenesis. These findings support a neuroimmune axis of AD, in which the interplay of adaptive and innate immune systems inside and outside the brain critically impacts the etiology and pathogenesis of AD. In this review, we discuss the complexities of AD neuropathology at the levels of genetics and cellular physiology, highlighting immune signaling pathways and genes associated with AD risk and interactions among both innate and adaptive immune cells in the AD brain. We emphasize the role of peripheral immune cells in AD and the mechanisms by which immune cells, such as T cells and monocytes, influence AD neuropathology, including microglial clearance of amyloid-β peptide, the key component of β-amyloid plaque cores, pro-inflammatory and cytotoxic activity of microglia, astrogliosis, and their interactions with the brain vasculature. Finally, we review the challenges and outlook for establishing immune-based therapies for treating and preventing AD.

Animal models to investigate the effects of inflammation on remyelination in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). In people with MS, impaired remyelination and axonal loss lead to debilitating long-term neurologic deficits. Current MS disease-modifying drugs mainly target peripheral immune cells and have demonstrated little efficacy for neuroprotection or promoting repair. To elucidate the pathological mechanisms and test therapeutic interventions, multiple animal models have been developed to recapitulate specific aspects of MS pathology, particularly the acute inflammatory stage. However, there are few animal models that facilitate the study of remyelination in the presence of inflammation, and none fully replicate the biology of chronic demyelination in MS. In this review, we describe the animal models that have provided insight into the mechanisms underlying demyelination, myelin repair, and potential therapeutic targets for remyelination. We highlight the limitations of studying remyelination in toxin-based demyelination models and discuss the combinatorial models that recapitulate the inflammatory microenvironment, which is now recognized to be a major inhibitor of remyelination mechanisms. These models may be useful in identifying novel therapeutics that promote CNS remyelination in inflammatory diseases such as MS.

Anti-Inflammatory Effects of GLP-1 Receptor Activation in the Brain in Neurodegenerative Diseases

The glucagon-like peptide-1 (GLP-1) is a pleiotropic hormone well known for its incretin effect in the glucose-dependent stimulation of insulin secretion. However, GLP-1 is also produced in the brain and displays a critical role in neuroprotection and inflammation by activating the GLP-1 receptor signaling pathways. Several studies in vivo and in vitro using preclinical models of neurodegenerative diseases show that GLP-1R activation has anti-inflammatory properties. This review explores the molecular mechanistic action of GLP-1 RAS in relation to inflammation in the brain. These findings update our knowledge of the potential benefits of GLP-1RAS actions in reducing the inflammatory response. These molecules emerge as a potential therapeutic tool in treating neurodegenerative diseases and neuroinflammatory pathologies.