Characterization of Gene Expression Phenotype in Amyotrophic Lateral Sclerosis Monocytes

Urinary neopterin: a novel biomarker of disease progression in amyotrophic lateral sclerosis

BACKGROUND

To evaluate urinary neopterin, a marker of pro-inflammatory state, as a potential biomarker of disease prognosis and progression in amyotrophic lateral sclerosis (ALS); and to compare its utility to urinary neurotrophin receptor p75 extracellular domain (p75^ECD ).

METHODS

Observational study including 21 healthy controls and 46 people with ALS, 29 of whom were sampled longitudinally. Neopterin and p75^ECD were measured using enzyme-linked immunoassays. Baseline and longitudinal changes in clinical measures, neopterin and urinary p75^ECD were examined, and prognostic utility explored by survival analysis.

RESULTS

At baseline, urinary neopterin was higher in ALS compared to controls (181.7 ± 78.9 μmol/mol creatinine vs 120.4 ± 60.8 μmol/mol creatinine, p= 0.002, Welch's t-test) and correlated with ALSFRS-R (r= -0.36, p= 0.01). Combining previously published urinary p75^ECD results from 22 ALS patients with a further 24 ALS patients, baseline urinary p75^ECD was also higher compared to healthy controls (6.0 ± 2.7 vs 3.2 ± 1.0 ng/mg creatinine p<0.0001) and correlated with ALSFRS-R (r= -0.36, p= 0.01). Urinary neopterin and p75^ECD correlated with each other at baseline (r= 0.38, p= 0.009). In longitudinal analysis, urinary neopterin increased on average (±SE) by 6.8 ± 1.1 μmol/mol creatinine per month (p<0.0001) and p75^ECD by 0.19 ± 0.02 ng/mg creatinine per month (p<0.0001) from diagnosis in 29 ALS patients.

CONCLUSION

Urinary neopterin holds promise as marker of disease progression in ALS and is worthy of future evaluation for its potential to predict response to anti-inflammatory therapies.

The Selective Loss of Purkinje Cells Induces Specific Peripheral Immune Alterations

The progression of neurodegenerative diseases is reciprocally associated with impairments in peripheral immune responses. We investigated different contexts of selective neurodegeneration to identify specific alterations of peripheral immune cells and, at the same time, discover potential biomarkers associated to this pathological condition. Consequently, a model of human cerebellar degeneration and ataxia -the Purkinje Cell Degeneration (PCD) mouse- has been employed, as it allows the study of different processes of selective neuronal death in the same animal, i.e., Purkinje cells in the cerebellum and mitral cells in the olfactory bulb. Infiltrated leukocytes were studied in both brain areas and compared with those from other standardized neuroinflammatory models obtained by administering either gamma radiation or lipopolysaccharide. Moreover, both myeloid and lymphoid splenic populations were analyzed by flow cytometry, focusing on markers of functional maturity and antigen presentation. The severity and type of neural damage and inflammation affected immune cell infiltration. Leukocytes were more numerous in the cerebellum of PCD mice, being located predominantly within those cerebellar layers mostly affected by neurodegeneration, in a completely different manner than the typical models of induced neuroinflammation. Furthermore, the milder degeneration of the olfactory bulb did not foster leukocyte attraction. Concerning the splenic analysis, in PCD mice we found: (1) a decreased percentage of several myeloid cell subsets, and (2) a reduced mean fluorescence intensity in those myeloid markers related to both antigen presentation and functional maturity. In conclusion, the selective degeneration of Purkinje cells triggers a specific effect on peripheral immune cells, fostering both attraction and functional changes. This fact endorses the employment of peripheral immune cell populations as concrete biomarkers for monitoring different neuronal death processes.

Local and remote interactions between macrophages and microglia in neurological conditions

In the central nervous system (CNS) parenchymal macrophages are called microglial cells and have a distinct developmental origin and can self-renew. However, during pathological conditions, when the blood-brain-barrier becomes leaky, including after injury, in multiple sclerosis or with glioblastoma, monocyte-derived macrophages (MDM) infiltrate the CNS and cohabit with microglia. In neurodegenerative diseases such as Alzheimer's disease or ALS, MDM mostly do not enter the CNS, and instead microglia take several identities. In the specific case of ALS, the affected motor neurons are even surrounded locally by microglia, while along the peripheral nerves, by MDM-derived macrophages. The specific functions and interactions of these different myeloid cells are only starting to be recognized, but hold high promise for more targeted therapies.

Phase 1b dose-escalation, safety, and pharmacokinetic study of IC14, a monoclonal antibody against CD14, for the treatment of amyotrophic lateral sclerosis

BACKGROUND

The primary objective was to demonstrate the safety and tolerability of monoclonal antibody against CD14 (IC14) (atibuclimab) in amyotrophic lateral sclerosis patients. The secondary objectives were pharmacokinetics, pharmacodynamics, and preliminary effects on disease status and biomarkers.

METHODS

In this open-label, dose-escalation trial, IC14 was administered at 2 mg/kg intravenous (IV) followed by 1 mg/kg/d IV × 3 (n = 3) and in subsequent patients at 4 mg/kg IV followed by 2 mg/kg/d IV × 3 (n = 7) (NCT03487263). Disease status was measured using the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, forced vital capacity, sniff nasal pressure, Edinburgh Cognitive and Behavioural ALS Screen, and Revised ALS-Specific Quality-of-Life Score. Disease biomarkers included cerebrospinal fluid and serum levels of neurofilament light chain (NfL) and urinary p75 neurotrophin receptor.

RESULTS

IC14 was safe and well tolerated. No antidrug antibodies were detected. The drug target saturation of monocyte CD14 receptors was rapid and sustained through day 8. There was no significant change in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, forced vital capacity, sniff nasal pressure, or Revised ALS-Specific Quality-of-Life Score following a single cycle of treatment. Cerebrospinal fluid NfL levels decreased in 6 of 9 patients sampled with declines of 15% to 40% between baseline (not significant [ns]) and day 8 in 3 patients. Serum NfL modestly decreased in 5 of 10 patients (ns) at day 8 and was sustained in 4 (4%-37%, ns) over 33 days of follow up.

CONCLUSION

IC14 quickly and durably saturated its target in all patients. This study demonstrated safety and tolerability in patients with amyotrophic lateral sclerosis. Even though only a single cycle of treatment was given, there were promising beneficial trends in the neurofilament light chain, a disease biomarker. The emerging understanding of the role of systemic inflammation in neurodegenerative diseases, and the potential for IC14 to serve as a safe, potent, and broad-spectrum inhibitor of immune dysregulation merits further clinical study.

CLINICAL TRIAL REGISTRATION

NCT03487263.

MINCR: A long non-coding RNA shared between cancer and neurodegeneration

The multitasking nature of lncRNAs allows them to play a central role in both physiological and pathological conditions. Often the same lncRNA can participate in different diseases. Specifically, the MYC-induced Long non-Coding RNA MINCR is upregulated in various cancer types, while downregulated in Amyotrophic Lateral Sclerosis patients. Therefore, this work aims to investigate MINCR potential mechanisms of action and its implications in cancer and neurodegeneration in relation to its expression levels in SH-SY5Y cells through RNA-sequencing approach. Our results show that MINCR overexpression causes massive alterations in cancer-related genes, leading to disruption in many fundamental processes, such as cell cycle and growth factor signaling. On the contrary, MINCR downregulation influences a small number of genes involved in different neurodegenerative disorders, mostly concerning RNA metabolism and inflammation. Thus, understanding the cause and functional consequences of MINCR deregulation gives important insights on potential pathogenetic mechanisms both in cancer and in neurodegeneration.

Exploring Aromatic Medicinal Compounds for the Treatment of Amyotrophic Lateral Sclerosis

Purpose: Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative condition, in which motor neurons start to degenerate due to the accumulation of protein aggregates in the neuron cytoplasm. The formation of aggregates causes neurotoxicity, facilitated by the N-terminal domain (NTD) of the transactive response DNA-binding protein-43 (TDP-43). Therapies used to treat ALS manage secondary symptoms, but do not stop the activity of the rogue NTD domain of TDP-43. Therefore, new drug candidates should be designed to deal efficiently with this disease by inhibiting the domains involved in the development of ALS. This study determined the chemical affinity of aromatic medicinal compounds with NTD. Screening of 1323 medicinal compounds was conducted with PYRX 0.9 software against NTD. Compounds obtained from this analysis were further used to predict absorption, distribution, metabolism, excretion, and toxic (ADMET) properties and their effect on major gene targets of ALS. Results: From 1300 + compounds, acetovanillone showed binding affinity for NTD and had good ADMET and drug likeness attributes. This compound reduced the expression of CXCL2, NOP56, and SOD1 genes implicated in ALS pathogenesis. Conclusion: These results concluded that acetovanillone is a candidate drug for in vitro and clinical studies into the exploitation of drugs within ALS therapeutics.

Serum programmed cell death proteins in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a multifactorial, multisystem pro-inflammatory neuromuscular disorder. Activation of programmed cell death-1 (PD-1), and its ligands, programmed cell death-ligand 1 and 2 (PD-L1/L2), leads to immune suppression. Serum soluble forms of these proteins, sPD-1/sPD-L1/sPD-L2, inhibit this suppression and promote pro-inflammatory responses. The purpose of this study was to determine if sPD-1, sPD-L1, and sPD-L2 were increased in sera of patients with ALS. sPD-1 and sPD-L2 were elevated in sera of patients and accurately reflected patients’ disease burdens. Increased sera levels of programmed cell death proteins reinforce the concept that peripheral pro-inflammatory responses contribute to systemic inflammation in patients with ALS.

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Immune regulatory checkpoint pathways play important roles in maintaining the homeostasis of the immune system.

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ALS and tumor pathobiologies may be thought of as opposite ends of a detrimental versus beneficial spectrum of pro-inflammatory immune responses.

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Programmed cell death-1 (PD-1) protein, and its ligands, programmed cell death-ligand 1 and 2 (PD-L1/PD-L2), three proteins involved in these regulatory pathways that suppress activation of immune cells.

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Serum soluble forms of these proteins, sPD-1/sPD-L1/sPD-L2, inhibit this suppression.

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sPD-1 levels were elevated in the sera of patients with ALS.

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sPD-1 was only elevated in sera from fast progressing patients with ALS.

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sPD-L1 was not increased in patients with ALS.

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sPD-L2 was increased in the sera of patients with ALS.

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sPD-L2 was increased in fast and slowly progressing patients with ALS.

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Sera sPD-1 and sPD-L2 positively correlated with patients’ disease burdens.

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sPD-1 positively correlated with sPD-L2.

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Sera sPD-1 and sPD-L2 positively correlated with patients’ sera LBP levels.

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Increased sera levels of programmed cell death proteins reinforce the concept that peripheral pro-inflammatory responses contribute to systemic inflammation in patients with ALS.

Amyotrophic lateral sclerosis transcriptomics reveals immunological effects of low-dose interleukin-2

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease causing upper and lower motor neuron loss and currently no effective disease-modifying treatment is available. A pathological feature of this disease is neuroinflammation, a mechanism which involves both CNS-resident and peripheral immune system cells. Regulatory T-cells are immune-suppressive agents known to be dramatically and progressively decreased in patients with amyotrophic lateral sclerosis. Low-dose interleukin-2 promotes regulatory T-cell expansion and was proposed as an immune-modulatory strategy for this disease. A randomized placebo-controlled pilot phase-II clinical trial called Immuno-Modulation in Amyotrophic Lateral Sclerosis was carried out to test safety and activity of low-dose interleukin-2 in 36 amyotrophic lateral sclerosis patients (NCT02059759). Participants were randomized to 1MIU, 2MIU-low-dose interleukin-2 or placebo and underwent one injection daily for 5 days every 28 days for three cycles. In this report, we describe the results of microarray gene expression profiling of trial participants' leukocyte population. We identified a dose-dependent increase in regulatory T-cell markers at the end of the treatment period. Longitudinal analysis revealed an alteration and inhibition of inflammatory pathways occurring promptly at the end of the first treatment cycle. These responses are less pronounced following the end of the third treatment cycle, although an activation of immune-regulatory pathways, involving regulatory T-cells and T helper 2 cells, was evident only after the last cycle. This indicates a cumulative effect of repeated low-dose interleukin-2 administration on regulatory T-cells. Our analysis suggested the existence of inter-individual variation amongst trial participants and we therefore classified patients into low, moderate and high-regulatory T-cell-responders. NanoString profiling revealed substantial baseline differences between participant immunological transcript expression profiles with the least responsive patients showing a more inflammatory-prone phenotype at the beginning of the trial. Finally, we identified two genes in which pre-treatment expression levels correlated with the magnitude of drug responsiveness. Therefore, we proposed a two-biomarker based regression model able to predict patient regulatory T-cell-response to low-dose interleukin-2. These findings and the application of this methodology could be particularly relevant for future precision medicine approaches to treat amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a systemic disease: peripheral contributions to inflammation-mediated neurodegeneration

PURPOSE OF REVIEW

Neuroinflammation is an important mediator of the pathogenesis of disease in amyotrophic lateral sclerosis (ALS). Genetic mutations such as C9orf72 have begun to define the numerous cell autonomous pathways that initiate motor neuron injury. Yet, it is the signalling to surrounding glia and peripherally derived immune cells that initiates the noncell autonomous inflammatory process and promotes self-propagating motor neuron cell death. The purpose of this review is to explore the systemic immune/inflammatory contributions to the pathogenesis of ALS: what are the peripheral pro-inflammatory signatures, what initiates their presence and do they represent potential therapeutic targets.

RECENT FINDINGS

In ALS, motor neuron cell death is initiated by multiple cell autonomous pathways leading to misfolded proteins, oxidative stress, altered mitochondria, impaired autophagy and altered RNA metabolism, which collectively promote noncell autonomous inflammatory reactivity. The resulting disease is characterized by activated microglia and astrocytes as well as peripherally derived pro-inflammatory innate and adaptive immune cells. In this unrelenting disorder, circulating blood monocytes and natural killer cells are pro-inflammatory. Furthermore, regulatory T lymphocytes are dysfunctional, and pro-inflammatory cytokines and acute phase proteins are elevated.

SUMMARY

The collective dysregulation of cells and cytokines in patients with ALS accurately reflect increased disease burdens, more rapid progression rates and reduced survival times, reinforcing the concept of ALS as a disorder with extensive systemic pro-inflammatory responses. These increased systemic pro-inflammatory immune constituents provide potentially meaningful therapeutic targets.

Monocyte CD14 and HLA-DR expression increases with disease duration and severity in amyotrophic lateral sclerosis

Objective: To investigate changes in immune markers and frequencies throughout disease progression in patients with amyotrophic lateral sclerosis (ALS). Methods: In this longitudinal study, serial blood samples were collected from 21 patients with ALS over a time period of up to 16 months. Flow cytometry was used to quantitate CD14, HLA-DR, and CD16 marker expression on monocyte subpopulations and neutrophils, as well as their cell population frequencies. A Generalized Estimating Equation model was used to assess the association between changes in these immune parameters and disease duration and the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R). Results: CD14 expression on monocyte subpopulations increased with both disease duration and a decrease in ALSFRS-R score in patients with ALS. HLA-DR expression on monocyte subpopulations also increased with disease severity and/or duration. The expression of CD16 did not change relative to disease duration or ALSFRS-R. Finally, patients had a reduction in non-classical monocytes and an increase in the classical to non-classical monocyte ratio throughout disease duration. Conclusion: The progressive immunological changes observed in this study provide further support that monocytes are implicated in ALS pathology. Monocytic CD14 and HLA-DR surface proteins may serve as a therapeutic target or criteria for the recruitment of patients with ALS into clinical trials for immunomodulatory therapies.

Interplay between immunity and amyotrophic lateral sclerosis: Clinical impact

Amyotrophic lateral sclerosis (ALS) is a debilitating and rapidly fatal neurodegenerative disease. Despite decades of research and many new insights into disease biology over the 150 years since the disease was first described, causative pathogenic mechanisms in ALS remain poorly understood, especially in sporadic cases. Our understanding of the role of the immune system in ALS pathophysiology, however, is rapidly expanding. The aim of this manuscript is to summarize the recent advances regarding the immune system involvement in ALS, with particular attention to clinical translation. We focus on the potential pathophysiologic mechanism of the immune system in ALS, discussing local and systemic factors (blood, cerebrospinal fluid, and microbiota) that influence ALS onset and progression in animal models and people. We also explore the potential of Positron Emission Tomography to detect neuroinflammation in vivo, and discuss ongoing clinical trials of therapies targeting the immune system. With validation in human patients, new evidence in this emerging field will serve to identify novel therapeutic targets and provide realistic hope for personalized treatment strategies.

Variability of the Expression Patterns of Neuroinflammatory Genes in Mononuclear Cells of Peripheral Blood in Amyotrophic Lateral Sclerosis

Abstract—Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease with steadily progressing death of motor neurons in the brain and spinal cord. The disease is incurable and results in the patient’s death within 3–5 years on average. The mechanisms of initiation, progression, and spread of the pathological process remain unclear. It seems that inflammatory reactions may be important for disease progression but this is not certain. We performed multiplex analysis of the expression of neuroinflammatory genes in mononuclear cells of peripheral blood from patients with different rates of ALS progression (n = 22) and compared these data with those observed in healthy volunteers. We found that the expression of 14 genes, specifically BAX, CLN3, PLEKHM1, AKT1, LAMP1, RAC2, VAV1, MPG, TFG, BRD2, CSK, MSN, GBA, and VIM, differed between the groups of patients and healthy volunteers (p < 0.05; q < 0.05). Genes associated with autophagia, apoptosis, adaptive immunity, and growth factor cascades prevail among these genes. We did not find any substantial differences in gene expression between patients with rapid and slow ALS progression. We revealed a subgroup of patients who exhibited significantly different expression of 208 or 262 genes compared to other ALS patients or healthy volunteers, respectively (p < 0.05; q < 0.05). Our data show the importance of not only central but also peripheral inflammatory reactions in the development of the pathological process associated with ALS.

Human Monocytes Plasticity in Neurodegeneration

Monocytes play a crucial role in immunity and tissue homeostasis. They constitute the first line of defense during the inflammatory process, playing a role in the pathogenesis and progression of diseases, making them an attractive therapeutic target. They are heterogeneous in morphology and surface marker expression, which suggest different molecular and physiological properties. Recent evidences have demonstrated their ability to enter the brain, and, as a consequence, their hypothetical role in different neurodegenerative diseases. In this review, we will discuss the current knowledge about the correlation between monocyte dysregulation in the brain and/or in the periphery and neurological diseases in humans. Here we will focus on the most common neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis.

Immune Response in Neurological Pathology: Emerging Role of Central and Peripheral Immune Crosstalk

Neuroinflammation is a key component of neurological disorders and is an important therapeutic target; however, immunotherapies have been largely unsuccessful. In cases where these therapies have succeeded, particularly multiple sclerosis, they have primarily focused on one aspect of the disease and leave room for improvement. More recently, the impact of the peripheral immune system is being recognized, since it has become evident that the central nervous system is not immune-privileged, as once thought. In this review, we highlight key interactions between central and peripheral immune cells in neurological disorders. While traditional approaches have examined these systems separately, the immune responses and processes in neurological disorders consist of substantial crosstalk between cells of the central and peripheral immune systems. Here, we provide an overview of major immune effector cells and the role of the blood-brain barrier in regard to neurological disorders and provide examples of this crosstalk in various disorders, including stroke and traumatic brain injury, multiple sclerosis, neurodegenerative diseases, and brain cancer. Finally, we propose targeting central-peripheral immune interactions as a potential improved therapeutic strategy to overcome failures in clinical translation.

Differential Epigenetic Signature of Corticospinal Motor Neurons in ALS

Corticospinal motor neurons (CSMN) are an indispensable neuron population for the motor neuron circuitry. They are excitatory projection neurons, which collect information from different regions of the brain and transmit it to spinal cord targets, initiating and controlling motor function. CSMN degeneration is pronounced cellular event in motor neurons diseases, such as amyotrophic lateral sclerosis (ALS). Genetic mutations contribute to only about ten percent of ALS. Thus understanding the involvement of other factors, such as epigenetic controls, is immensely valuable. Here, we investigated epigenomic signature of CSMN that become diseased due to misfolded SOD1 toxicity and TDP-43 pathology, by performing quantitative analysis of 5-methylcytosine (5mC) and 5-hydroxymethycytosine (5hmC) expression profiles during end-stage of the disease in hSOD1^G93A, and prpTDP-43^A315T mice. Our analysis revealed that expression of 5mC was specifically reduced in CSMN of both hSOD1^G93A and prpTDP-43^A315T mice. However, 5hmC expression was increased in the CSMN that becomes diseased due to misfolded SOD1 and decreased in CSMN that degenerates due to TDP-43 pathology. These results suggest the presence of a distinct difference between different underlying causes. These differential epigenetic events might modulate the expression profiles of select genes, and ultimately contribute to the different paths that lead to CSMN vulnerability in ALS.

Non-neuronal cells in amyotrophic lateral sclerosis - from pathogenesis to biomarkers

The prevailing motor neuron-centric view of amyotrophic lateral sclerosis (ALS) pathogenesis could be an important factor in the failure to identify disease-modifying therapy for this neurodegenerative disorder. Non-neuronal cells have crucial homeostatic functions within the CNS and evidence of involvement of these cells in the pathophysiology of several neurodegenerative disorders, including ALS, is accumulating. Microglia and astrocytes, in crosstalk with peripheral immune cells, can exert both neuroprotective and adverse effects, resulting in a highly nuanced range of neuronal and non-neuronal cell interactions. This Review provides an overview of the diverse roles of non-neuronal cells in relation to the pathogenesis of ALS and the emerging potential of non-neuronal cell biomarkers to advance therapeutic development.

Monocyte-Derived Macrophages Contribute to Chitinase Dysregulation in Amyotrophic Lateral Sclerosis: A Pilot Study

Neuroinflammation significantly contributes to Amyotrophic Lateral Sclerosis (ALS) pathology. In lieu of this, reports of elevated chitinase levels in ALS are interesting, as they are established surrogate markers of a chronic inflammatory response. While post-mortem studies have indicated glial expression, the cellular sources for these moieties remain to be fully understood. Therefore, the objective of this pilot study was to examine whether the peripheral immune system also contributes to chitinase dysregulation in ALS. The temporal expression of CHIT1, CHI3L1, and CHI3L2 in non-polarized monocyte-derived macrophages (MoMas) from ALS patients and healthy controls (HCs) was examined. We demonstrate that while CHIT1 and CHI3L1 display similar temporal expression dynamics in both groups, profound between-group differences were noted for these targets at later time-points i.e., when cells were fully differentiated. CHIT1 and CHI3L1 expression were significantly higher in MoMas from ALS patients at both the transcriptomic and protein level, with CHI3L1 levels also being influenced by age. Conversely, CHI3L2 expression was not influenced by disease state, culture duration, or age. Here, we demonstrate for the first time, that in ALS, circulating immune cells have an intrinsically augmented potential for chitinase production that may propagate chronic neuroinflammation, and how the ageing immune system itself contributes to neurodegeneration.

Ex vivo expansion of dysfunctional regulatory T lymphocytes restores suppressive function in Parkinson's disease

Inflammation is a pathological hallmark of Parkinson's disease (PD). Chronic pro-inflammatory responses contribute to the loss of neurons in the neurodegenerative process. The present study was undertaken to define the peripheral innate and adaptive immune contributions to inflammation in patients with PD. Immunophenotyping revealed a shift of peripheral myeloid and lymphoid cells towards a pro-inflammatory phenotype. Regulatory T cells (Tregs) were reduced in number, and their suppression of T responder proliferation decreased. The PD Tregs did not suppress activated pro-inflammatory myeloid cells. Ex vivo expansion of Tregs from patients with PD restored and enhanced their suppressive functions while expanded Tregs displayed increased expression of foxp3, il2ra (CD25), nt5e (CD73), il10, il13, ctla4, pdcd1 (PD1), and gzmb. Collectively, these findings documented a shift towards a pro-inflammatory peripheral immune response in patients with PD; the loss of Treg suppressive functions may contribute significantly to this response, supporting PD as a disorder with extensive systemic pro-inflammatory responses. The restoration and enhancement of Treg suppressive functions following ex vivo expansion may provide a potential cell therapeutic approach for patients with PD.

Bidirectional communication between mast cells and the gut-brain axis in neurodegenerative diseases: Avenues for therapeutic intervention

Although the global incidence of neurodegenerative diseases has been steadily increasing, especially in adults, there are no effective therapeutic interventions. Neurodegeneration is a heterogeneous group of disorders that is characterized by the activation of immune cells in the central nervous system (CNS) (e.g., mast cells and microglia) and subsequent neuroinflammation. Mast cells are found in the brain and the gastrointestinal tract and play a role in "tuning" neuroimmune responses. The complex bidirectional communication between mast cells and gut microbiota coordinates various dynamic neuro-cellular responses, which propagates neuronal impulses from the gastrointestinal tract into the CNS. Numerous inflammatory mediators from degranulated mast cells alter intestinal gut permeability and disrupt blood-brain barrier, which results in the promotion of neuroinflammatory processes leading to neurological disorders, thereby offsetting the balance in immune-surveillance. Emerging evidence supports the hypothesis that gut-microbiota exert a pivotal role in inflammatory signaling through the activation of immune and inflammatory cells. Communication between inflammatory cytokines and neurocircuits via the gut-brain axis (GBA) affects behavioral responses, activates mast cells and microglia that causes neuroinflammation, which is associated with neurological diseases. In this comprehensive review, we focus on what is currently known about mast cells and the gut-brain axis relationship, and how this relationship is connected to neurodegenerative diseases. We hope that further elucidating the bidirectional communication between mast cells and the GBA will not only stimulate future research on neurodegenerative diseases but will also identify new opportunities for therapeutic interventions.

Microbiota-Host Immunity Communication in Neurodegenerative Disorders: Bioengineering Challenges for In Vitro Modeling

Human microbiota communicates with its host by secreting signaling metabolites, enzymes, or structural components. Its homeostasis strongly influences the modulation of human tissue barriers and immune system. Dysbiosis-induced peripheral immunity response can propagate bacterial and pro-inflammatory signals to the whole body, including the brain. This immune-mediated communication may contribute to several neurodegenerative disorders, as Alzheimer's disease. In fact, neurodegeneration is associated with dysbiosis and neuroinflammation. The interplay between the microbial communities and the brain is complex and bidirectional, and a great deal of interest is emerging to define the exact mechanisms. This review focuses on microbiota-immunity-central nervous system (CNS) communication and shows how gut and oral microbiota populations trigger immune cells, propagating inflammation from the periphery to the cerebral parenchyma, thus contributing to the onset and progression of neurodegeneration. Moreover, an overview of the technological challenges with in vitro modeling of the microbiota-immunity-CNS axis, offering interesting technological hints about the most advanced solutions and current technologies is provided.

Exit Strategies in Natalizumab-Treated RRMS at High Risk of Progressive Multifocal Leukoencephalopathy: a Multicentre Comparison Study

The main aim of the study is to evaluate the efficacy and safety profile of ocrelizumab (OCR), rituximab (RTX), and cladribine (CLA), employed as natalizumab (NTZ) exit strategies in relapsing-remitting multiple sclerosis (RRMS) patients at high-risk for progressive multifocal leukoencephalopathy (PML). This is a multicentre, retrospective, real-world study on consecutive RRMS patients from eleven tertiary Italian MS centres, who switched from NTZ to OCR, RTX, and CLA from January 1st, 2019, to December 31st, 2019. The primary study outcomes were the annualized relapse rate (ARR) and magnetic resonance imaging (MRI) outcome. Treatment effects were estimated by the inverse probability treatment weighting (IPTW), based on propensity-score (PS) approach. Additional endpoint included confirmed disability progression (CDP) as measured by Expanded Disability Status Scale and adverse events (AEs). Patients satisfying predefined inclusion and exclusion criteria were 120; 64 switched to OCR, 36 to RTX, and 20 to CLA. Patients from the 3 groups did not show differences for baseline characteristics, also after post hoc analysis. The IPTW PS-adjusted models revealed that patients on OCR had a lower risk for ARR than patients on CLA (ExpBOCR 0.485, CI 95% 0.264-0.893, p = 0.020). This result was confirmed also for 12-month MRI activity (ExpBOCR 0.248 CI 95% 0.065-0.948, p = 0.042). No differences were found in other pairwise comparisons (OCR vs RTX and RTX vs CLA) for the investigated outcomes. AEs were similar among the 3 groups. Anti-CD20 drugs were revealed to be effective and safe options as NTZ exit strategies. All investigated DMTs showed a good safety profile.

Modification of Glial Cell Activation through Dendritic Cell Vaccination: Promises for Treatment of Neurodegenerative Diseases

Accumulation of misfolded tau, amyloid β (Aβ), and alpha-synuclein (α-syn) proteins is the fundamental contributor to many neurodegenerative diseases, namely Parkinson's (PD) and AD. Such protein aggregations trigger activation of immune mechanisms in neuronal and glial, mainly M1-type microglia cells, leading to release of pro-inflammatory mediators, and subsequent neuronal dysfunction and apoptosis. Despite the described neurotoxic features for glial cells, recruitment of peripheral leukocytes to the brain and their conversion to neuroprotective M2-type microglia can mitigate neurodegeneration by clearing extracellular protein accumulations or residues. Based on these observations, it was speculated that Dendritic cell (DC)-based vaccination, by making use of DCs as natural adjuvants, could be used for treatment of neurodegenerative disorders. DCs potentiated by disease-specific antigens can also enhance T helper 2 (Th2)-specific immune response and by production of specific antibodies contribute to clearance of intracellular aggregations, as well as enhancing regulatory T cell response. Thus, enhancement of immune response by DC vaccine therapy can potentially augment glial polarization into the neuroprotective phenotype, enhance antibody production, and at the same time balance neuronal cells' repair, renewal, and protection. The characteristic feature of this method of treatment is to maintain the equilibrium in the immune response rather than targeting a single mediator in the disease and their application in other neurodegenerative diseases should be addressed. However, the safety of these methods should be investigated by clinical trials.

Neurodegenerative Disease and the NLRP3 Inflammasome

The prevalence of neurodegenerative disease has increased significantly in recent years, and with a rapidly aging global population, this trend is expected to continue. These diseases are characterised by a progressive neuronal loss in the brain or peripheral nervous system, and generally involve protein aggregation, as well as metabolic abnormalities and immune dysregulation. Although the vast majority of neurodegeneration is idiopathic, there are many known genetic and environmental triggers. In the past decade, research exploring low-grade systemic inflammation and its impact on the development and progression of neurodegenerative disease has increased. A particular research focus has been whether systemic inflammation arises only as a secondary effect of disease or is also a cause of pathology. The inflammasomes, and more specifically the NLRP3 inflammasome, a crucial component of the innate immune system, is usually activated in response to infection or tissue damage. Dysregulation of the NLRP3 inflammasome has been implicated in the progression of several neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and prion diseases. This review aims to summarise current literature on the role of the NLRP3 inflammasome in the pathogenesis of neurodegenerative diseases, and recent work investigating NLRP3 inflammasome inhibition as a potential future therapy.

Genome-wide genetic links between amyotrophic lateral sclerosis and autoimmune diseases

BACKGROUND

Epidemiological and clinical studies have suggested comorbidity between amyotrophic lateral sclerosis (ALS) and autoimmune disorders. However, little is known about their shared genetic architecture.

METHODS

To examine the relation between ALS and 10 autoimmune diseases, including asthma, celiac disease (CeD), Crohn's disease (CD), inflammatory bowel disease (IBD), multiple sclerosis (MS), psoriasis, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), type 1 diabetes (T1D), and ulcerative colitis (UC), and identify shared risk loci, we first estimated the genetic correlation using summary statistics from genome-wide association studies, and then analyzed the genetic enrichment leveraging the conditional false discovery rate statistical method.

RESULTS

We identified a significant positive genetic correlation between ALS and CeD, MS, RA, and SLE, as well as a significant negative genetic correlation between ALS and IBD, UC, and CD. Robust genetic enrichment was observed between ALS and CeD and MS, and moderate enrichment was found between ALS and UC and T1D. Thirteen shared genetic loci were identified, among which five were suggestively significant in another ALS GWAS, namely rs3828599 (GPX3), rs3849943 (C9orf72), rs7154847 (G2E3), rs6571361 (SCFD1), and rs9903355 (GGNBP2). By integrating cis-expression quantitative trait loci analyses in Braineac and GTEx, we further identified GGNBP2, ATXN3, and SLC9A8 as novel ALS risk genes. Functional enrichment analysis indicated that the shared risk genes were involved in four pathways including membrane trafficking, vesicle-mediated transport, ER to Golgi anterograde transport, and transport to the Golgi and subsequent modification.

CONCLUSIONS

Our findings demonstrate a specific genetic correlation between ALS and autoimmune diseases and identify shared risk loci, including three novel ALS risk genes. These results provide a better understanding for the pleiotropy of ALS and have implications for future therapeutic trials.

Macrophage roles in peripheral nervous system injury and pathology: Allies in neuromuscular junction recovery

Peripheral nerve injuries remain challenging to treat despite extensive research on reparative processes at the injury site. Recent studies have emphasized the importance of immune cells, particularly macrophages, in recovery from nerve injury. Macrophage plasticity enables numerous functions at the injury site. At early time points, macrophages perform inflammatory functions, but at later time points, they adopt pro-regenerative phenotypes to support nerve regeneration. Research has largely been limited, however, to the injury site. The neuromuscular junction (NMJ), the synapse between the nerve terminal and end target muscle, has received comparatively less attention, despite the importance of NMJ reinnervation for motor recovery. Macrophages are present at the NMJ following nerve injury. Moreover, in denervating diseases, such as amyotrophic lateral sclerosis (ALS), macrophages may also play beneficial roles at the NMJ. Evidence of positive macrophages roles at the injury site after peripheral nerve injury and at the NMJ in denervating pathologies suggest that macrophages may promote NMJ reinnervation. In this review, we discuss the intersection of nerve injury and immunity, with a focus on macrophages.

Neuroimmune connections between corticotropin-releasing hormone and mast cells: novel strategies for the treatment of neurodegenerative diseases

Corticotropin-releasing hormone is a critical component of the hypothalamic–pituitary–adrenal axis, which plays a major role in the body’s immune response to stress. Mast cells are both sensors and effectors in the interaction between the nervous and immune systems. As first responders to stress, mast cells can initiate, amplify and prolong neuroimmune responses upon activation. Corticotropin-releasing hormone plays a pivotal role in triggering stress responses and related diseases by acting on its receptors in mast cells. Corticotropin-releasing hormone can stimulate mast cell activation, influence the activation of immune cells by peripheral nerves and modulate neuroimmune interactions. The latest evidence shows that the release of corticotropin-releasing hormone induces the degranulation of mast cells under stress conditions, leading to disruption of the blood-brain barrier, which plays an important role in neurological diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, autism spectrum disorder and amyotrophic lateral sclerosis. Recent studies suggest that stress increases intestinal permeability and disrupts the blood-brain barrier through corticotropin-releasing hormone-mediated activation of mast cells, providing new insight into the complex interplay between the brain and gastrointestinal tract. The neuroimmune target of mast cells is the site at which the corticotropin-releasing hormone directly participates in the inflammatory responses of nerve terminals. In this review, we focus on the neuroimmune connections between corticotropin-releasing hormone and mast cells, with the aim of providing novel potential therapeutic targets for inflammatory, autoimmune and nervous system diseases.

Umbilical Cord Mesenchymal Stem Cells in Amyotrophic Lateral Sclerosis: an Original Study

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is still incurable. Although different therapies can affect the health and survival of patients. Our aim is to evaluate the effect of umbilical mesenchymal stem cells administrated intrathecally to patients with amyotrophic lateral sclerosis on disability development and survival.

METHODS

This case-control study involved 67 patients treated with Wharton's jelly mesenchymal stem cells (WJ-MSC). The treated patients were paired with 67 reference patients from the PRO-ACT database which contains patient records from 23 ALS clinical studies (phase 2/3). Patients in the treatment and reference groups were fully matched in terms of race, sex, onset of symptoms (bulbar/spinal), FT9 disease stage at the beginning of therapy and concomitant amyotrophic lateral sclerosis medications. Progression rates prior to treatment varied within a range of ± 0.5 points. All patients received three intrathecal injections of Wharton's jelly-derived mesenchymal stem cells every two months at a dose of 30 × 106 cells. Patients were assessed using the ALSFRS-R scale. Survival times were followed-up until March 2020.

RESULTS

Median survival time increased two-fold in all groups. In terms of progression, three response types measured in ALSFRS-R were observed: decreased progression rate (n = 21, 31.3%), no change in progression rate (n = 33, 49.3%) and increased progression rate (n = 13, 19.4%). Risk-benefit ratios were favorable in all groups. No serious adverse drug reactions were observed.

INTERPRETATION

Wharton's jelly-derived mesenchymal stem cells therapy is safe and effective in some ALS patients, regardless of the clinical features and demographic factors excluding sex. The female sex and a good therapeutic response to the first administration are significant predictors of efficacy following further administrations. Graphical Abstract Medical therapeutic experiment with retrospective case-control analyses.

Elevated acute phase proteins reflect peripheral inflammation and disease severity in patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a multifactorial, multisystem pro-inflammatory neuromuscular disorder compromising muscle function resulting in death. Neuroinflammation is known to accelerate disease progression and accentuate disease severity, but peripheral inflammatory processes are not well documented. Acute phase proteins (APPs), plasma proteins synthesized in the liver, are increased in response to inflammation. The objective of this study was to provide evidence for peripheral inflammation by examining levels of APPs, and their contribution to disease burden and progression rates. Levels of APPs, including soluble CD14 (sCD14), lipopolysaccharide binding protein (LBP), and C-reactive protein (CRP), were elevated in sera, and correlated positively with increased disease burden and faster progression. sCD14 was also elevated in patients' CSF and urine. After a 3 year follow-up, 72% of the patients with sCD14 levels above the receiver operating characteristics cutoff were deceased whereas only 28% below the cutoff were deceased. Furthermore, disease onset sites were associated with disease progression rates and APP levels. These APPs were not elevated in sera of patients with Alzheimer's Disease, frontotemporal dementia, or Parkinson's Disease. These collective APPs accurately reflect disease burden, progression rates, and survival times, reinforcing the concept of ALS as a disorder with extensive systemic pro-inflammatory responses.

Immunity in amyotrophic lateral sclerosis: blurred lines between excessive inflammation and inefficient immune responses

Despite wide genetic, environmental and clinical heterogeneity in amyotrophic lateral sclerosis, a rapidly fatal neurodegenerative disease targeting motoneurons, neuroinflammation is a common finding. It is marked by local glial activation, T cell infiltration and systemic immune system activation. The immune system has a prominent role in the pathogenesis of various chronic diseases, hence some of them, including some types of cancer, are successfully targeted by immunotherapeutic approaches. However, various anti-inflammatory or immunosuppressive therapies in amyotrophic lateral sclerosis have failed. This prompted increased scrutiny over the immune-mediated processes underlying amyotrophic lateral sclerosis. Perhaps the biggest conundrum is that amyotrophic lateral sclerosis pathogenesis exhibits features of three otherwise distinct immune dysfunctions-excessive inflammation, autoimmunity and inefficient immune responses. Epidemiological and genome-wide association studies show only minimal overlap between amyotrophic lateral sclerosis and autoimmune diseases, so excessive inflammation is usually thought to be secondary to protein aggregation, mitochondrial damage or other stresses. In contrast, several recently characterized amyotrophic lateral sclerosis-linked mutations, including those in TBK1, OPTN, CYLD and C9orf72, could lead to inefficient immune responses and/or damage pile-up, suggesting that an innate immunodeficiency may also be a trigger and/or modifier of this disease. In such cases, non-selective immunosuppression would further restrict neuroprotective immune responses. Here we discuss multiple layers of immune-mediated neuroprotection and neurotoxicity in amyotrophic lateral sclerosis. Particular focus is placed on individual patient mutations that directly or indirectly affect the immune system, and the mechanisms by which these mutations influence disease progression. The topic of immunity in amyotrophic lateral sclerosis is timely and relevant, because it is one of the few common and potentially malleable denominators in this heterogenous disease. Importantly, amyotrophic lateral sclerosis progression has recently been intricately linked to patient T cell and monocyte profiles, as well as polymorphisms in cytokine and chemokine receptors. For this reason, precise patient stratification based on immunophenotyping will be crucial for efficient therapies.

Peripheral and Central Nervous System Immune Response Crosstalk in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by muscle weakness due to the degeneration of the upper and lower motor neurons. Neuroinflammation is known as a prominent pathological feature of ALS. Although neuroinflammation cannot trigger ALS, activated central nervous system (CNS) microglia and astrocytes, proinflammatory periphery monocytes/macrophages and T lymphocytes, and infiltrated monocytes/macrophages and T lymphocytes, as well as the immunoreactive molecules they release, are closely related to disease progression. The crosstalk between the peripheral and CNS immune components mentioned above significantly correlates with survival in patients with ALS. This review provides an update on the role of this crosstalk between the CNS and peripheral immune responses in ALS. Additionally, we discuss changes in the composition of gut microbiota because these can directly or indirectly influence this crosstalk. These recent advances may well provide innovative ways for targeting the molecules associated with this crosstalk and breaking the current treatment impasse in ALS.

Immune dysregulation in amyotrophic lateral sclerosis: mechanisms and emerging therapies

Neuroinflammation is a common pathological feature of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), and is characterised by activated CNS microglia and astroglia, proinflammatory peripheral lymphocytes, and macrophages. Data from clinical studies show that multiple genetic mutations linked to ALS (eg, mutations in SOD1, TARDBP, and C9orf72) enhance this neuroinflammation, which provides compelling evidence for immune dysregulation in the pathogenesis of ALS. Transgenic rodent models expressing these mutations induce an ALS-like disease with accompanying inflammatory responses, confirming the immune system's involvement in disease progression. Even in the absence of known genetic alterations, immune dysregulation has been shown to lead to dysfunctional regulatory T lymphocytes and increased proinflammatory macrophages in clinical studies. Therefore, an improved understanding of the biological processes that induce this immune dysregulation will help to identify therapeutic strategies that circumvent or ameliorate the pathogenesis of ALS. Emerging cell-based therapies hold the promise of accomplishing this goal and, therefore, improving quality of life and extending survival in patients with ALS.

Immunosuppressive Functions of M2 Macrophages Derived from iPSCs of Patients with ALS and Healthy Controls

Amyotrophic lateral sclerosis (ALS) is a disorder with immune alterations that augment disease severity. M2 macrophages benefit diabetic and nephrotic mice by suppressing the pro-inflammatory state. However, neither have M2 cells been investigated in ALS nor have human induced pluripotent stem cell (iPSC)-derived M2 cells been thoroughly studied for immunosuppressive potentials. Here, iPSCs of C9orf72 mutated or sporadic ALS patients were differentiated into M2 macrophages, which suppressed activation of pro-inflammatory M1 macrophages as well as proliferation of ALS CD4⁺CD25^- Tc (Teffs). M2 cells converted ALS Teffs into CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs) and rescued Tregs of ALS patients from losing CD25 and Foxp3. Furthermore, Tregs induced or rescued by iPSC-derived M2 had strong suppressive functions. ALS iPSC-derived M2 cells including those with C9orf72 mutation had similar immunomodulatory activity as control iPSC-derived M2 cells. This study demonstrates that M2 cells differentiated from iPSCs of ALS patients are immunosuppressive, boost ALS Tregs, and may serve as a candidate for immune-cell-based therapy to mitigate inflammation in ALS.

The Peripheral Immune System and Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease that is defined by loss of upper and lower motor neurons, associated with accumulation of protein aggregates in cells. There is also pathology in extra-motor areas of the brain, Possible causes of cell death include failure to deal with the aggregated proteins, glutamate toxicity and mitochondrial failure. ALS also involves abnormalities of metabolism and the immune system, including neuroinflammation in the brain and spinal cord. Strikingly, there are also abnormalities of the peripheral immune system, with alterations of T lymphocytes, monocytes, complement and cytokines in the peripheral blood of patients with ALS. The precise contribution of the peripheral immune system in ALS pathogenesis is an active area of research. Although some trials of immunomodulatory agents have been negative, there is strong preclinical evidence of benefit from immune modulation and further trials are currently underway. Here, we review the emerging evidence implicating peripheral immune alterations contributing to ALS, and their potential as future therapeutic targets for clinical intervention.

Complement: Bridging the innate and adaptive immune systems in sterile inflammation

The complement system is a collection of soluble and membrane-bound proteins that together act as a powerful amplifier of the innate and adaptive immune systems. Although its role in infection is well established, complement is becoming increasingly recognized as a key contributor to sterile inflammation, a chronic inflammatory process often associated with noncommunicable diseases. In this context, damaged tissues release danger signals and trigger complement, which acts on a range of leukocytes to augment and bridge the innate and adaptive immune systems. Given the detrimental effect of chronic inflammation, the complement system is therefore well placed as an anti-inflammatory drug target. In this review, we provide a general outline of the sterile activators, effectors, and targets of the complement system and a series of examples (i.e., hypertension, cancer, allograft transplant rejection, and neuroinflammation) that highlight complement's ability to bridge the 2 arms of the immune system.

Circulating RNAs as Potential Biomarkers in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a complex multi-system neurodegenerative disorder with currently limited diagnostic and no therapeutic options. Despite the intense efforts no clinically applicable biomarkers for ALS are yet established. Most current research is thus focused, in particular, in identifying potential non-invasive circulating biomarkers for more rapid and accurate diagnosis and monitoring of the disease. In this review, we have focused on messenger RNA (mRNA), non-coding RNAs (lncRNAs), micro RNAs (miRNAs) and circular RNA (circRNAs) as potential biomarkers for ALS in peripheral blood serum, plasma and cells. The most promising miRNAs include miR-206, miR-133b, miR-27a, mi-338-3p, miR-183, miR-451, let-7 and miR-125b. To test clinical potential of this miRNA panel, a useful approach may be to perform such analysis on larger multi-center scale using similar experimental design. However, other types of RNAs (lncRNAs, circRNAs and mRNAs) that, together with miRNAs, represent RNA networks, have not been yet extensively studied in blood samples of patients with ALS. Additional research has to be done in order to find robust circulating biomarkers and therapeutic targets that will distinguish key RNA interactions in specific ALS-types to facilitate diagnosis, predict progression and design therapy.

Increased activation ability of monocytes from ALS patients

Neuroinflammation is increasingly recognized as an important mediator of disease progression in patients with amyotrophic lateral sclerosis (ALS). Recent research suggests that pro-inflammatory microglia in ALS mice promote motoneuron cytotoxicity by secreting reactive oxygen species and pro-inflammatory cytokines. Gene expression analyses indicate that peripheral circulating monocytes from ALS patients are skewed towards a pro-inflammatory state that contributes to ALS disease progression. Better understanding of macrophage phenotypes of ALS patients is therefore warranted. In this study, we demonstrate that M1 macrophages differentiated from ALS circulating monocytes produced more pro-inflammatory cytokines, including IL-6 and TNFα, than M1 macrophages derived from healthy control monocytes. More importantly, IL-6 protein levels of ALS M1 macrophages positively correlated with disease burden, and TNFα protein levels of ALS M1 macrophages positively correlate with disease progression rates. Collectively, these data suggest that monocytes from ALS patients are more readily activated and differentiated to a pro-inflammatory M1 phenotype, and represent a potential target for immunomodulatory therapy.

Monocytes and neutrophils are associated with clinical features in amyotrophic lateral sclerosis

Immunity has emerged as a key player in neurodegenerative diseases such as amyotrophic lateral sclerosis, with recent studies documenting aberrant immune changes in patients and animal models. A challenging aspect of amyotrophic lateral sclerosis research is the heterogeneous nature of the disease. In this study, we investigate the associations between peripheral blood myeloid cell populations and clinical features characteristic of amyotrophic lateral sclerosis. Peripheral blood leukocytes from 23 healthy controls and 48 patients with amyotrophic lateral sclerosis were analysed to measure myeloid cell alterations. The proportion of monocytes (classical, intermediates and non-classical subpopulations) and neutrophils, as well as the expression of select surface markers, were quantitated using flow cytometry. Given the heterogeneous nature of amyotrophic lateral sclerosis, multivariable linear analyses were performed to investigate associations between patients' myeloid profile and clinical features, such as the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, bulbar subscore of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, change in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale over disease duration and respiratory function. We demonstrate a shift in monocyte subpopulations in patients with amyotrophic lateral sclerosis, with the ratio of classical to non-classical monocytes increased compared with healthy controls. In line with this, patients with greater disease severity, as determined by a lower Revised Amyotrophic Lateral Sclerosis Functional Rating Scale score, had reduced non-classical monocytes. Interestingly, patients with greater bulbar involvement had a reduction in the proportions of classical, intermediate and non-classical monocyte populations. We also revealed several notable associations between myeloid marker expression and clinical features in amyotrophic lateral sclerosis. CD16 expression on neutrophils was increased in patients with greater disease severity and a faster rate of disease progression, whereas HLA-DR expression on all monocyte populations was elevated in patients with greater respiratory impairment. This study demonstrates that patients with amyotrophic lateral sclerosis with distinct clinical features have differential myeloid cell signatures. Identified cell populations and markers may be candidates for targeted mechanistic studies and immunomodulation therapies in amyotrophic lateral sclerosis.

Masitinib as an add-on therapy to riluzole in patients with amyotrophic lateral sclerosis: a randomized clinical trial

Objective: To assess masitinib in the treatment of ALS. Methods: Double-blind study, randomly assigning 394 patients (1:1:1) to receive riluzole (100 mg/d) plus placebo or masitinib at 4.5 or 3.0 mg/kg/d. Following a blinded transition from phase 2 to phase 2/3, a prospectively defined two-tiered design was implemented based on ALSFRS-R progression rate from disease-onset to baseline (ΔFS). This approach selects a more homogeneous primary efficacy population ("Normal Progressors", ΔFS < 1.1 points/month) while concurrently permitting secondary assessment of the broader population. Primary endpoint was decline in ALSFRS-R at week-48 (ΔALSFRS-R), with the high-dose "Normal Progressor" cohort being the prospectively declared primary efficacy population. Missing data were imputed via last observation carried forward (LOCF) methodology with sensitivity analyses performed to test robustness. Results: For the primary efficacy population, masitinib (n = 99) showed significant benefit over placebo (n = 102) with a ΔALSFRS-R between-group difference (ΔLSM) of 3.4 (95% CI 0.65-6.13; p = 0.016), corresponding to a 27% slowing in rate of functional decline (LOCF methodology). Sensitivity analyses were all convergent, including the conservative multiple imputation technique of FCS-REGPMM with a ΔLSM of 3.4 (95% CI 0.53-6.33; p = 0.020). Secondary endpoints (ALSAQ-40, FVC, and time-to-event analysis) were also significant. Conversely, no significant treatment-effect according to ΔALSFRS-R was seen for the broader "Normal and Fast Progressor" masitinib 4.5 mg/kg/d cohort, or either of the low-dose (masitinib 3.0 mg/kg/d) cohorts. Rates of treatment-emergent adverse events (AEs) (regardless of causality or post-onset ΔFS) were 88% with masitinib 4.5 mg/kg/d, 85% with 3.0 mg/kg/d, and 79% with placebo. Likewise, rates of serious AE were 31, 23, and 18%, respectively. No distinct event contributed to the higher rate observed for masitinib and no deaths were related to masitinib. Conclusions: Results show that masitinib at 4.5 mg/kg/d can benefit patients with ALS. A confirmatory phase 3 study will be initiated to substantiate these data.

Phase 2 randomized placebo controlled double blind study to assess the efficacy and safety of tecfidera in patients with amyotrophic lateral sclerosis (TEALS Study): Study protocol clinical trial (SPIRIT Compliant)

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disorder of the human motor system. Neuroinflammation appears to be an important modulator of disease progression in ALS. Specifically, reduction of regulatory T cell (Treg) levels, along with an increase in pro-inflammatory effector T cells, macrophage activation and upregulation of co-stimulatory pathways have all been associated with a rapid disease course in ALS. Autologous infusion of expanded Tregs into sporadic ALS patients, resulted in greater suppressive function, slowing of disease progression and stabilization of respiratory function. Tecfidera (dimethyl fumarate) increases the ratio of anti-inflammatory (Treg) to proinflammatory T-cells in patients with relapsing remitting multiple sclerosis and rebalances the regulatory: inflammatory axis towards a neuroprotective phenotype. Consequently, the aim of this study was to assess the efficacy, safety, and tolerability of Tecfidera in sporadic ALS.

METHODS

The study is an investigator led Phase 2 multi-center, randomized, placebo controlled, double blind clinical trial assessing the efficacy and safety of Tecfidera in patients with sporadic ALS. The study duration is 40 weeks, with a 36-week study period and end of study visit occurring at 40 weeks or at early termination/withdrawal from study. The TEALS study has been registered with the Australian and New Zealand Clinical Trials registry (ANZCTR) under the trials registration number ACTRN12618000534280 and has been approved by the Human Research Ethics Committee and Research Governance Office at the lead site (Westmead Hospital) with the ethics number HREC/17/WMEAD/353. The participating sites have obtained site specific ethics and governance approvals from the local institution.

RESULTS

The primary endpoint is slowing of disease progression as reflected by the differences in the ALS Functional Rating Score-Revised (ALSFRS-R) score at Week 36. The secondary endpoints will include effects in survival, lower motor neuron function, respiratory function, quality of life and safety.

CONCLUSION

This Phase 2 multi-center, randomized, placebo controlled, double blind clinical trial will provide evidence of efficacy and safety of Tecfidera in sporadic ALS.

High neutrophil-to-lymphocyte ratio predicts short survival duration in amyotrophic lateral sclerosis

The present study aimed to investigate the prognostic importance of the neutrophil-to-lymphocyte ratio (NLR) in patients with amyotrophic lateral sclerosis (ALS). Among 322 patients diagnosed as having definite, probable, or possible ALS at a single tertiary hospital, 194 patients were included in the final analysis. Patients were divided into three groups (T1, T2, and T3) according to the tertile of their NLR. Survival rate was significantly lower in T3 compared to the other groups (log-rank test; T1 vs. T3, p = 0.009; T2 vs. T3, p = 0.008). Median survival duration was 37.0 (24.0–56.0), 32.5 (19.5–51.2), and 22.0 (17.0–38.0) months in T1, T2, and T3, respectively. In a multivariable Cox proportional hazards regression analysis, the hazard ratio of age at onset, bulbar-onset, and NLR (T3/T1) was 1.04 (1.02–1.06, p < 0.001), 1.68 (1.10–2.57, p = 0.015), and 1.60 (1.01–2.51, p = 0.041), respectively. A high baseline NLR may serve as a useful indicator for short survival duration in patients with ALS.

Hochu-Ekki-To Improves Motor Function in an Amyotrophic Lateral Sclerosis Animal Model

Hochu-ekki-to (Bojungikgi-Tang (BJIGT) in Korea; Bu-Zhong-Yi-Qi Tang in Chinese), a traditional herbal prescription, has been widely used in Asia. Hochu-ekki-to (HET) is used to enhance the immune system in respiratory disorders, improve the nutritional status associated with chronic diseases, enhance the mucosal immune system, and improve learning and memory. Amyotrophic lateral sclerosis (ALS) is pathologically characterized by motor neuron cell death and muscle paralysis, and is an adult-onset motor neuron disease. Several pathological mechanisms of ALS have been reported by clinical and in vitro/in vivo studies using ALS models. However, the underlying mechanisms remain elusive, and the critical pathological target needs to be identified before effective drugs can be developed for patients with ALS. Since ALS is a disease involving both motor neuron death and skeletal muscle paralysis, suitable therapy with optimal treatment effects would involve a motor neuron target combined with a skeletal muscle target. Herbal medicine is effective for complex diseases because it consists of multiple components for multiple targets. Therefore, we investigated the effect of the herbal medicine HET on motor function and survival in hSOD1^G93A transgenic mice. HET was orally administered once a day for 6 weeks from the age of 2 months (the pre-symptomatic stage) of hSOD1^G93A transgenic mice. We used the rota-rod test and foot printing test to examine motor activity, and Western blotting and H&E staining for evaluation of the effects of HET in the gastrocnemius muscle and lumbar (L4–5) spinal cord of mice. We found that HET treatment dramatically inhibited inflammation and oxidative stress both in the spinal cord and gastrocnemius of hSOD1^G93A transgenic mice. Furthermore, HET treatment improved motor function and extended the survival of hSOD1^G93A transgenic mice. Our findings suggest that HET treatment may modulate the immune reaction in muscles and neurons to delay disease progression in a model of ALS.

Peripheral inflammatory markers and clinical correlations in patients with frontotemporal lobar degeneration with and without the C9orf72 repeat expansion

In this study, our aim was to evaluate potential peripheral inflammatory changes in frontotemporal lobar degeneration (FTLD) patients carrying or not the C9orf72 repeat expansion. To this end, levels of several inflammatory markers (MCP-1, RANTES, IL-10, IL-17A, IL-12p, IFN-γ, IL-1β, IL-8, and hs-CRP) and blood cells counts in plasma and/or serum of FTLD patients (N = 98) with or without the C9orf72 repeat expansion were analyzed. In addition, we evaluated whether the analyzed peripheral inflammatory markers correlated with disease progression or distinct clinical phenotypes under the heterogenous FTLD spectrum. Elevated levels of pro-inflammatory RANTES or MCP-1 and decreased levels of anti-inflammatory IL-10 were found to associate with Parkinsonism and a more rapid disease progression, indicated by longitudinal measurements of either MMSE or ADCS-ADL decline. These findings were observed in the total cohort in general, whereas the C9orf72 repeat expansion carriers showed only slight differences in IL-10 and hemoglobin levels compared to non-carriers. Furthermore, these C9orf72 repeat expansion-associated differences were observed mostly in male subjects. The females in general showed elevated levels of several pro-inflammatory markers compared to males regardless of the C9orf72 genotype. Our study suggests that pro-inflammatory changes observed in the early symptomatic phase of FTLD are associated with distinct clinical profiles and a more rapid disease progression, and that the C9orf72 repeat expansion and gender may also affect the inflammatory profile in FTLD.

A Therapeutic Strategy for Alzheimer's Disease Focused on Immune-inflammatory Modulation

Alzheimer's disease (AD), the most common form of dementia, has emerged as a major global public health challenge. However, the complexity of AD in its biological, genetic, and clinical aspects has hindered the development of effective therapeutic agents. Research plans that integrate new drug discoveries are urgently needed, including those based on novel and reliable biomarkers that reflect not only clinical phenotype, but also genetic and neuroimaging information. Therapeutic strategies such as stratification (i.e., subgrouping of patients having similar clinical characteristics or genetic background) and personalized medicine could be set as new directions for developing effective drugs for AD. In this review, we describe a therapeutic strategy that is based on immune-inflammation modulation for a subgroup of AD and related dementias, arguing that the use of stratification and personalized medicine is a promising way to achieve targeted medicine. The Korean AD Research Platform Initiative based on Immune-Inflammatory biomarkers (K-ARPI) has recently launched a strategy to develop novel biomarkers to identify a subpopulation of patients with AD and to develop new drug candidates for delaying the progression of AD by modulating toxic immune inflammatory response. Sphingosine kinase 1 (SphK1) and its metabolites, triggering receptor expressed on myeloid cells-2 (TREM2) related signals, and actin motility related proteins including Nck-associated protein 1 (Nap1) were selected as promising targets to modulate neuroinflammation. Their roles in stratification and personalized medicine will be discussed.

TDP-43 knockdown causes innate immune activation via protein kinase R in astrocytes

TAR-DNA binding protein 43 (TDP-43) is a multifunctional RNA binding protein directly implicated in the etiology of amyotrophic lateral sclerosis (ALS). Previous studies have demonstrated that loss of TDP-43 function leads to intracellular accumulation of non-coding repetitive element transcripts and double-stranded RNA (dsRNA). These events could cause immune activation and contribute to the neuroinflammation observed in ALS, but this possibility has not been investigated. Here, we knock down TDP-43 in primary rat astrocytes via siRNA, and we use RNA-seq, immunofluorescence, and immunoblotting to show that this results in: 1) accumulation of repetitive element transcripts and dsRNA; and 2) pro-inflammatory gene and protein expression consistent with innate immune signaling and astrocyte activation. We also show that both chemical inhibition and siRNA knockdown of protein kinase R (PKR), a dsRNA-activated kinase implicated in the innate immune response, block the expression of all activation markers assayed. Based on these findings, we suggest that intracellular accumulation of endogenous dsRNA may be a novel and important mechanism underlying the pathogenesis of ALS (and perhaps other neurodegenerative diseases), and that PKR inhibitors may have the potential to prevent reactive astrocytosis in ALS.

Monozygotic twins and triplets discordant for amyotrophic lateral sclerosis display differential methylation and gene expression

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterised by the loss of upper and lower motor neurons. ALS exhibits high phenotypic variability including age and site of onset, and disease duration. To uncover epigenetic and transcriptomic factors that may modify an ALS phenotype, we used a cohort of Australian monozygotic twins (n = 3 pairs) and triplets (n = 1 set) that are discordant for ALS and represent sporadic ALS and the two most common types of familial ALS, linked to C9orf72 and SOD1. Illumina Infinium HumanMethylation450K BeadChip, EpiTYPER and RNA-Seq analyses in these ALS-discordant twins/triplets and control twins (n = 2 pairs), implicated genes with consistent longitudinal differential DNA methylation and/or gene expression. Two identified genes, RAD9B and C8orf46, showed significant differential methylation in an extended cohort of >1000 ALS cases and controls. Combined longitudinal methylation-transcription analysis within a single twin set implicated CCNF, DPP6, RAMP3, and CCS, which have been previously associated with ALS. Longitudinal transcriptome data showed an 8-fold enrichment of immune function genes and under-representation of transcription and protein modification genes in ALS. Examination of these changes in a large Australian sporadic ALS cohort suggest a broader role in ALS. Furthermore, we observe that increased methylation age is a signature of ALS in older patients.

Gut microbiota in ALS: possible role in pathogenesis?

Introduction: The gut microbiota has important roles in maintaining human health. The microbiota and its metabolic byproducts could play a role in the pathogenesis of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Areas covered: The authors evaluate the methods of assessing the gut microbiota, and also review how the gut microbiota affects the various physiological functions of the gut. The authors then consider how gut dysbiosis could theoretically affect the pathogenesis of ALS. They present the current evidence regarding the composition of the gut microbiota in ALS and in rodent models of ALS. Finally, the authors review therapies that could improve gut dysbiosis in the context of ALS. Expert opinion: Currently reported studies suggest some instances of gut dysbiosis in ALS patients and mouse models; however, these studies are limited, and more information with well-controlled larger datasets is required to make a definitive judgment about the role of the gut microbiota in ALS pathogenesis. Overall this is an emerging field that is worthy of further investigation. The authors advocate for larger studies using modern metagenomic techniques to address the current knowledge gaps.