Regulatory T-lymphocytes mediate amyotrophic lateral sclerosis progression and survival

Tweaking Mesenchymal Stem/Progenitor Cell Immunomodulatory Properties with Viral Vectors Delivering Cytokines

Mesenchymal Stem Cells (MSCs) can be found in various body sites. Their main role is to differentiate into cartilage, bone, muscle, and fat cells to allow tissue maintenance and repair. During inflammation, MSCs exhibit important immunomodulatory properties that are not constitutive, but require activation, upon which they may exert immunosuppressive functions. MSCs are defined as "sensors of inflammation" since they modulate their ability of interfering with the immune system both in vitro and in vivo upon interaction with different factors. MSCs may influence immune responses through different mechanisms, such as direct cell-to-cell contact, release of soluble factors, and through the induction of anergy and apoptosis. Human MSCs are defined as plastic-adherent cells expressing specific surface molecules. Lack of MHC class II antigens makes them appealing as allogeneic tools for the therapy of both autoimmune diseases and cancer. MSC therapeutic potential could be highly enhanced by the expression of exogenous cytokines provided by transduction with viral vectors. In this review, we attempt to summarize the results of a great number of in vitro and in vivo studies aimed at improving the ability of MSCs as immunomodulators in the therapy of autoimmune, degenerative diseases and cancer. We will also compare results obtained with different vectors to deliver heterologous genes to these cells.

A robust, good manufacturing practice-compliant, clinical-scale procedure to generate regulatory T cells from patients with amyotrophic lateral sclerosis for adoptive cell therapy

Regulatory T cells (Tregs) play a fundamental role in the maintenance of self-tolerance and immune homeostasis. Defects in Treg function and/or frequencies have been reported in multiple disease models. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting upper and lower motor neurons. Compelling evidence supports a neuroprotective role for Tregs in this disease. Indeed, rapid progression in ALS patients is associated with decreased FoxP3 expression and Treg frequencies. Thus, we propose that strategies to restore Treg number and function may slow disease progression in ALS. In this study, we developed a robust, Good Manufacturing Practice (GMP)-compliant procedure to enrich and expand Tregs from ALS patients. Tregs isolated from these patients were phenotypically similar to those from healthy individuals but were impaired in their ability to suppress T-cell effector function. In vitro expansion of Tregs for 4 weeks in the presence of GMP-grade anti-CD3/CD28 beads, interleukin (IL)-2 and rapamcyin resulted in a 25- to 200-fold increase in their number and restored their immunoregulatory activity. Collectively, our data facilitate and support the implementation of clinical trials of adoptive therapy with ex vivo expanded and highly suppressive Tregs in patients with ALS.

Loss-of-function mutations in the C9ORF72 mouse ortholog cause fatal autoimmune disease

C9ORF72 mutations are found in a significant fraction of patients suffering from amyotrophic lateral sclerosis and frontotemporal dementia, yet the function of the C9ORF72 gene product remains poorly understood. We show that mice harboring loss-of-function mutations in the ortholog of C9ORF72 develop splenomegaly, neutrophilia, thrombocytopenia, increased expression of inflammatory cytokines, and severe autoimmunity, ultimately leading to a high mortality rate. Transplantation of mutant mouse bone marrow into wild-type recipients was sufficient to recapitulate the phenotypes observed in the mutant animals, including autoimmunity and premature mortality. Reciprocally, transplantation of wild-type mouse bone marrow into mutant mice improved their phenotype. We conclude that C9ORF72 serves an important function within the hematopoietic system to restrict inflammation and the development of autoimmunity.

Major Histocompatibility Complex I Expression by Motor Neurons and Its Implication in Amyotrophic Lateral Sclerosis

Neuronal expression of major histocompatibility complex I (MHCI)-related molecules in adults and during CNS diseases is involved in the synaptic plasticity and axonal regeneration with mechanisms either dependent or independent of their immune functions. Motor neurons are highly responsive in triggering the expression of MHCI molecules during normal aging or following insults and diseases, and this has implications in the synaptic controls, axonal regeneration, and neuromuscular junction stability of these neurons. We recently reported that MHCI and immunoproteasome are strongly activated in spinal motor neurons and their peripheral motor axon in a mouse model of familial amyotrophic lateral sclerosis (ALS) during the course of the disease. This response was prominent in ALS mice with slower disease progression in which the axonal structure and function was better preserved than in fast-progressing mice. This review summarizes and discusses our observations in the light of knowledge about the possible role of MHCI in motor neurons providing additional insight into the pathophysiology of ALS.

Systemic inflammatory response and neuromuscular involvement in amyotrophic lateral sclerosis

Objective:

To evaluate the combined blood expression of neuromuscular and inflammatory biomarkers as predictors of disease progression and prognosis in amyotrophic lateral sclerosis (ALS).

Methods:

Logistic regression adjusted for markers of the systemic inflammatory state and principal component analysis were carried out on plasma levels of creatine kinase (CK), ferritin, and 11 cytokines measured in 95 patients with ALS and 88 healthy controls. Levels of circulating biomarkers were used to study survival by Cox regression analysis and correlated with disease progression and neurofilament light chain (NfL) levels available from a previous study. Cytokines expression was also tested in blood samples longitudinally collected for up to 4 years from 59 patients with ALS.

Results:

Significantly higher levels of CK, ferritin, tumor necrosis factor (TNF)–α, and interleukin (IL)–1β, IL-2, IL-8, IL-12p70, IL-4, IL-5, IL-10, and IL-13 and lower levels of interferon (IFN)–γ were found in plasma samples from patients with ALS compared to controls. IL-6, TNF-α, and IFN-γ were the most highly regulated markers when all explanatory variables were jointly analyzed. High ferritin and IL-2 levels were predictors of poor survival. IL-5 levels were positively correlated with CK, as was TNF-α with NfL. IL-6 was strongly associated with CRP levels and was the only marker showing increasing expression towards end-stage disease in the longitudinal analysis.

Conclusions:

Neuromuscular pathology in ALS involves the systemic regulation of inflammatory markers mostly active on T-cell immune responses. Disease stratification based on the prognostic value of circulating inflammatory markers could improve clinical trials design in ALS.

Reduced levels of alpha-1-antitrypsin in cerebrospinal fluid of amyotrophic lateral sclerosis patients: a novel approach for a potential treatment

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative motor neuron disease that involves activation of the immune system and inflammatory response in the nervous system. Reduced level of the immuno-modulatory and anti-inflammatory protein alpha-1-antitrypsin (AAT) is associated with inflammation-related pathologies. The objective of the present is to determine AAT levels and IL-23 in the cerebrospinal fluid (CSF) of ALS patients and control group.

FINDINGS

CSF samples from newly diagnosed ALS patients and age-matched controls were analyzed for AAT and IL-23 by ELISA and magnetic luminex screening, respectively. A statistically significant reduction of 45 % in mean AAT levels was observed in the CSF of ALS patients (21.4 μg/ml) as compared to the control group (mean 38.8 μg/ml, p = 0.013). A statistically significant increase of 30.8 % in CSF mean levels of the pro-inflammatory cytokine IL-23 was observed in ALS patients (1647 pg/ml) in comparison to the controls (1259 pg/ml, p = 0.012). A negative correlation coefficient (r = -0.543) was obtained by linear regression analysis of the two measured parameters (p = 0.036).

CONCLUSIONS

Reduced AAT and elevated IL-23 CSF levels support the notion of neuroinflammatory process occurring in ALS patients. Increasing AAT levels in the patients' nervous system should be further investigated as a new therapeutic approach and a novel potential tool for ALS treatment.

IL-10 Controls Early Microglial Phenotypes and Disease Onset in ALS Caused by Misfolded Superoxide Dismutase 1

While reactive microgliosis is a hallmark of advanced stages of amyotrophic lateral sclerosis (ALS), the role of microglial cells in events initiating and/or precipitating disease onset is largely unknown. Here we provide novel in vivo evidence of a distinct adaptive shift in functional microglial phenotypes in preclinical stages of superoxide dismutase 1 (SOD1)-mutant-mediated disease. Using a mouse model for live imaging of microglial activation crossed with SOD1(G93A) and SOD1(G37R) mouse models, we discovered that the preonset phase of SOD1-mediated disease is characterized by development of distinct anti-inflammatory profile and attenuated innate immune/TLR2 responses to lipopolysaccharide (LPS) challenge. This microglial phenotype was associated with a 16-fold overexpression of anti-inflammatory cytokine IL-10 in baseline conditions followed by a 4.5-fold increase following LPS challenge. While infusion of IL-10R blocking antibody, initiated at day 60, caused a significant increase in markers of microglial activation and precipitated clinical onset of disease, a targeted overexpression of IL-10 in microglial cells, delivered via viral vectors expressed under CD11b promoter, significantly delayed disease onset and increased survival of SOD1(G93A) mice. We propose that the high IL-10 levels in resident microglia in early ALS represent a homeostatic and compensatory "adaptive immune escape" mechanism acting as a nonneuronal determinant of clinical onset of disease. Significance statement: We report here for the first time that changing the immune profile of brain microglia may significantly affect clinical onset and duration of disease in ALS models. We discovered that in presymptomatic disease microglial cells overexpress anti-inflammatory cytokine IL-10. Given that IL-10 is major homeostatic cytokine and its production becomes deregulated with aging, this may suggest that the capacity of microglia to adequately produce IL-10 may be compromised in ALS. We show that blocking IL-10 increased inflammation and precipitated clinical disease onset, whereas overexpression of IL-10 in microglia using a gene therapy approach significantly delayed disease onset and increased survival of ALS mice. Based on our results, we propose that targeted overexpression of IL-10 in microglia may have therapeutic potential in ALS.

Central Nervous System-Peripheral Immune System Dialogue in Neurological Disorders: Possible Application of Neuroimmunology in Urology

Previous concepts of immune-privileged sites obscured the role of peripheral immune cells in neurological disorders and excluded the consideration of the potential benefits of immunotherapy. Recently, however, numerous studies have demonstrated that the blood–brain barrier in the central nervous system is an educational barrier rather than an absolute barrier to peripheral immune cells. Emerging knowledge of immune-privileged sites suggests that peripheral immune cells can infiltrate these sites via educative gates and that crosstalk can occur between infiltrating immune cells and the central nervous system parenchyma. This concept can be expanded to the testis, which has long been considered an immune-privileged site, and to neurogenic bladder dysfunction. Thus, we propose that the relationship between peripheral immune cells, the brain, and the urologic system should be considered as an additional possible mechanism in urologic diseases, and that immunotherapy might be an alternative therapeutic strategy in treating neurogenic bladder dysfunction.

Th17 Cell Response in SOD1G93A Mice following Motor Nerve Injury

An increased risk of ALS has been reported for veterans, varsity athletes, and professional football players. The mechanism underlying the increased risk in these populations has not been identified; however, it has been proposed that motor nerve injury may trigger immune responses which, in turn, can accelerate the progression of ALS. Accumulating evidence indicates that abnormal immune reactions and inflammation are involved in the pathogenesis of ALS, but the specific immune cells involved have not been clearly defined. To understand how nerve injury and immune responses may contribute to ALS development, we investigated responses of CD4⁺ T cell after facial motor nerve axotomy (FNA) at a presymptomatic stage in a transgenic mouse model of ALS (B6SJL SOD1^G93A). SOD1^G93A mice, compared with WT mice, displayed an increase in the basal activation state of CD4⁺ T cells and higher frequency of Th17 cells, which were further enhanced by FNA. In conclusion, SOD1^G93A mice exhibit abnormal CD4⁺ T cell activation with increased levels of Th17 cells prior to the onset of neurological symptoms. Motor nerve injury exacerbates Th17 cell responses and may contribute to the development of ALS, especially in those who carry genetic susceptibility to this disease.

Unusual association of amyotrophic lateral sclerosis and myasthenia gravis: A dysregulation of the adaptive immune system?

Myasthenia gravis is an autoimmune disorder affecting neuromuscular junctions that has been associated with a small increased risk of amyotrophic lateral sclerosis (ALS). Here, we describe a retrospective series of seven cases with a concomitant diagnosis of ALS and myasthenia gravis, collected among the 18 French reference centers for ALS in a twelve year period. After careful review, only six patients strictly met the diagnostic criteria for both ALS and myasthenia gravis. In these patients, limb onset of ALS was reported in five (83%) cases. Localization of myasthenia gravis initial symptoms was ocular in three (50%) cases, generalized in two (33%) and bulbar in one (17%). Median delay between onset of the two conditions was 19 months (6-319 months). Anti-acetylcholine receptor antibodies testing was positive in all cases. All patients were treated with riluzole and one had an associated immune-mediated disease. In the one last ALS case, the final diagnosis was false-positivity for anti-acetylcholine receptor antibodies. The co-occurrence of ALS and myasthenia gravis is rare and requires strict diagnostic criteria. Its demonstration needs thoughtful interpretation of electrophysiological results and exclusion of false positivity for myasthenia gravis antibody testing in some ALS cases. This association may be triggered by a dysfunction of adaptive immunity.

ACAID as a potential therapeutic approach to modulate inflammation in neurodegenerative diseases

The progressive loss of neurons and inflammation characterizes neurodegenerative diseases. Although the etiology, progression and outcome of different neurodegenerative diseases are varied, they share chronic inflammation maintained largely by central nervous system (CNS)-derived antigens recognized by T cells. Inflammation can be beneficial by recruiting immune cells to kill pathogens or to clear cell debris resulting from the primary insult. However, chronic inflammation exacerbates and perpetuates tissue damage. An increasing number of therapies that attempt to modulate neuroinflammation have been developed. However, so far none has succeeded in decreasing the secondary damage associated with chronic inflammation. A potential strategy to modulate the immune system is related to the induction of tolerance to CNS antigens. In this line, it is our hypothesis that this could be accomplished by using anterior chamber associated immune deviation (ACAID) as a strategy. Thus, we review current knowledge regarding some neurodegenerative diseases and the associated immune response that causes inflammation. In addition, we discuss further our hypothesis of the possible usefulness of ACAID as a therapeutic strategy to ameliorate damage to the CNS.

Immunomodulation as a neuroprotective and therapeutic strategy for Parkinson's disease

While immune control is associated with nigrostriatal neuroprotection for Parkinson's disease, direct cause and effect relationships have not yet been realized, and modulating the immune system for therapeutic gain has been openly debated. Here, we review how innate and adaptive immunity affect disease pathobiology, and how each could be harnessed for treatment. The overarching idea is to employ immunopharmacologics as neuroprotective strategies for disease. The aim of the current work is to review disease-modifying treatments that are currently being developed as neuroprotective strategies for PD in experimental animal models and for human disease translation. The long-term goal of this research is to effectively harness the immune system to slow or prevent PD pathobiology.

Neuroinflammation in motor neuron disease

Increasing evidence suggests that the pathogenesis of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) is not restricted to the neurons but attributed to the abnormal interactions of neurons and surrounding glial and lymphoid cells. These findings led to the concept of non-cell autonomous neurodegeneration. Neuroinflammation, which is mediated by activated glial cells and infiltrated lymphocytes and accompanied by the subsequent production of proinflammatory cytokines and neurotoxic or neuroprotective molecules, is characteristic to the pathology in ALS and is a key component for non-cell autonomous neurodegeneration. This review covers the involvement of microglia and astrocytes in the ALS mouse models and human ALS, and it also covers the deregulated pathways in motor neurons, which are involved in initiating the disease. Based on the cell-type specific pathomechanisms of motor neuron disease, targeting of neuroinflammation could lead to future therapeutic strategies for ALS and could be potentially applied to other neurodegenerative diseases.

CD4 + T Cells and Neuroprotection: Relevance to Motoneuron Injury and Disease

We have established a physiologically relevant mechanism of CD4+ T cell-mediated neuroprotection involving axotomized wildtype (WT) mouse facial motoneurons (FMN) with significance in the treatment of amyotrophic lateral sclerosis (ALS), a fatal MN disease. Use of the transgenic mouse model of ALS involving expression of human mutant superoxide dismutase genes (SOD1(G93A); abbreviated here as mSOD1) has accelerated basic ALS research. Superimposition of facial nerve axotomy (FNA) on the mSOD1 mouse during pre-symptomatic stages indicates that they behave like immunodeficient mice in terms of increased FMN loss and decreased functional recovery, through a mechanism that, paradoxically, is not inherent within the MN itself, but, instead, involves a defect in peripheral immune: CNS glial cell interactions. Our goal is to utilize our WT mouse model of immune-mediated neuroprotection after FNA as a template to elucidate how a malfunctioning peripheral immune system contributes to motoneuron cell loss in the mSOD1 mouse. This review will discuss potential immune defects in ALS, as well as provide an up-to-date understanding of how the CD4+ effector T cells provide neuroprotection to motoneurons through regulation of the central microglial and astrocytic response to injury. We will discuss an IL-10 cascade within the facial nucleus that requires a functional CD4+ T cell trigger for activation. The review will discuss the role of T cells in ALS, and our recent reconstitution experiments utilizing our model of T cell-mediated neuroprotection in WT vs mSOD1 mice after FNA. Identification of defects in neural:immune interactions could provide targets for therapeutic intervention in ALS.

Humoral factors in ALS patients during disease progression

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting upper and lower motor neurons in the CNS and leading to paralysis and death. There are currently no effective treatments for ALS due to the complexity and heterogeneity of factors involved in motor neuron degeneration. A complex of interrelated effectors have been identified in ALS, yet systemic factors indicating and/or reflecting pathological disease developments are uncertain. The purpose of the study was to identify humoral effectors as potential biomarkers during disease progression.

METHODS

Thirteen clinically definite ALS patients and seven non-neurological controls enrolled in the study. Peripheral blood samples were obtained from each ALS patient and control at two visits separated by 6 months. The Revised ALS Functional Rating Scale (ALSFRS-R) was used to evaluate overall ALS-patient functional status at each visit. Eleven humoral factors were analyzed in sera. Cytokine levels (GM-CSF, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, and TNF-α) were determined using the Bio-Rad Bio-Plex® Luminex 200 multiplex assay system. Nitrite, a breakdown product of NO, was quantified using a Griess Reagent System. Glutathione (GSH) concentrations were measured using a Glutathione Fluorometric Assay Kit.

RESULTS

ALS patients had ALSFRS-R scores of 30.5 ± 1.9 on their first visit and 27.3 ± 2.7 on the second visit, indicating slight disease progression. Serum multiplex cytokine panels revealed statistically significant changes in IL-2, IL-5, IL-6, and IL-8 levels in ALS patients depending on disease status at each visit. Nitrite serum levels trended upwards in ALS patients while serum GSH concentrations were drastically decreased in sera from ALS patients versus controls at both visits.

CONCLUSIONS

Our results demonstrated a systemic pro-inflammatory state and impaired antioxidant system in ALS patients during disease progression. Increased levels of pro-inflammatory IL-6, IL-8, and nitrite and significantly decreased endogenous antioxidant GSH levels could identify these humoral constituents as systemic biomarkers for ALS. However, systemic changes in IL-2, IL-5, and IL-6 levels determined between visits in ALS patients might indicate adaptive immune system responses dependent on current disease stage. These novel findings, showing dynamic changes in humoral effectors during disease progression, could be important for development of an effective treatment for ALS.

Editorial on the original article entitled "Genetic validation of a therapeutic target in a mouse model of ALS" published in the Science Translational Medicine on August 6, 2014

Amyotrophic lateral sclerosis (ALS) still remains a deadly neurodegenerative disease, mainly characterized by the combined degeneration of both upper and lower motor neurons (MNs). The pathology perspective is changed after 2006 due to the demonstration of common inclusions in ALS and Frontotemporal Dementia (non-tauFTD). Genetics largely contributed to further define the common mechanisms of both diseases but the large numbers of sporadic cases still remain unsolved. Transgenic mice models demonstrated the non-cell autonomous nature of ALS, being surrounding cells as astrocytes, microglial cells, and olygodendrocytes crucial in determining MN degeneration. More recently, the use of embryonic stem cells (ESCs) and/or IPSCs contributed to provide in vitro models for the ALS pathology and biological assay of clinical relevance. The combined use of ESC and SOD1 transgenic model of ALS has been pioneering used. The prostanoid receptor DP1 has been elegantly demonstrated to mediate the glial toxicity to stem-cell derived MNs in vitro. This evidence has been translated in vivo: the genetic ablation of DP1 in the SOD1G93A mice extended life span, decreasing microglial activation and MN loss. This paper is quite compelling, at the cutting edge of the stem cell-transgenic translation, demonstrating that discoveries derived from stem cells can be corroborated in vivo and possibly translated to humans.

Lack of TNF-alpha receptor type 2 protects motor neurons in a cellular model of amyotrophic lateral sclerosis and in mutant SOD1 mice but does not affect disease progression

Changes in the homeostasis of tumor necrosis factor α (TNFα) have been demonstrated in patients and experimental models of amyotrophic lateral sclerosis (ALS). However, the contribution of TNFα to the development of ALS is still debated. TNFα is expressed by glia and neurons and acts through the membrane receptors TNFR1 and TNFR2, which may have opposite effects in neurodegeneration. We investigated the role of TNFα and its receptors in the selective motor neuron death in ALS in vitro and in vivo. TNFR2 expressed by astrocytes and neurons, but not TNFR1, was implicated in motor neuron loss in primary SOD1-G93A co-cultures. Deleting TNFR2 from SOD1-G93A mice, there was partial but significant protection of spinal motor neurons, sciatic nerves, and tibialis muscles. However, no improvement of motor impairment or survival was observed. Since the sciatic nerves of SOD1-G93A/TNFR2-/- mice showed high phospho-TAR DNA-binding protein 43 (TDP-43) accumulation and low levels of acetyl-tubulin, two indices of axonal dysfunction, the lack of symptom improvement in these mice might be due to impaired function of rescued motor neurons. These results indicate the interaction between TNFR2 and membrane-bound TNFα as an innovative pathway involved in motor neuron death. Nevertheless, its inhibition is not sufficient to stop disease progression in ALS mice, underlining the complexity of this pathology. We show evidence of the involvement of neuronal and astroglial TNFR2 in the motor neuron degeneration in ALS. Both concur to cause motor neuron death in primary astrocyte/spinal neuron co-cultures. TNFR2 deletion partially protects motor neurons and sciatic nerves in SOD1-G93A mice but does not improve their symptoms and survival. However, TNFR2 could be a new target for multi-intervention therapies.

Emerging mechanisms of molecular pathology in ALS

Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable.

Phase I trial of repeated intrathecal autologous bone marrow-derived mesenchymal stromal cells in amyotrophic lateral sclerosis

Stem cell therapy is an emerging alternative therapeutic or disease-modifying strategy for amyotrophic lateral sclerosis (ALS). The aim of this open-label phase I clinical trial was to evaluate the safety of two repeated intrathecal injections of autologous bone marrow (BM)-derived mesenchymal stromal cells (MSCs) in ALS patients. Eight patients with definite or probable ALS were enrolled. After a 3-month lead-in period, autologous MSCs were isolated two times from the BM at an interval of 26 days and were then expanded in vitro for 28 days and suspended in autologous cerebrospinal fluid. Of the 8 patients, 7 received 2 intrathecal injections of autologous MSCs (1 × 10(6) cells per kg) 26 days apart. Clinical or laboratory measurements were recorded to evaluate the safety 12 months after the first MSC injection. The ALS Functional Rating Scale-Revised (ALSFRS-R), the Appel ALS score, and forced vital capacity were used to evaluate the patients' disease status. One patient died before treatment and was withdrawn from the study. With the exception of that patient, no serious adverse events were observed during the 12-month follow-up period. Most of the adverse events were self-limited or subsided after supportive treatment within 4 days. Decline in the ALSFRS-R score was not accelerated during the 6-month follow-up period. Two repeated intrathecal injections of autologous MSCs were safe and feasible throughout the duration of the 12-month follow-up period.

SIGNIFICANCE

Stem cell therapy is an emerging alternative therapeutic or disease-modifying strategy for amyotrophic lateral sclerosis (ALS). To the authors' best knowledge, there are no clinical trials to evaluate the safety of repeated intrathecal injections of autologous bone marrow mesenchymal stromal cells in ALS. After the clinical trial (phase I/II) was conducted, the stem cell (HYNR-CS, NEURONATA-R) was included in the revision of the regulations on orphan drug designation (number 160; December 31, 2013) and approved as a New Drug Application (Department of Cell and Gene Therapy 233; July 30, 2014) by the Korean Food and Drug Administration. The phase II trial is expected to be reported later.

Evidence for fungal infection in cerebrospinal fluid and brain tissue from patients with amyotrophic lateral sclerosis

Among neurogenerative diseases, amyotrophic lateral sclerosis (ALS) is a fatal illness characterized by a progressive motor neuron dysfunction in the motor cortex, brainstem and spinal cord. ALS is the most common form of motor neuron disease; yet, to date, the exact etiology of ALS remains unknown. In the present work, we have explored the possibility of fungal infection in cerebrospinal fluid (CSF) and in brain tissue from ALS patients. Fungal antigens, as well as DNA from several fungi, were detected in CSF from ALS patients. Additionally, examination of brain sections from the frontal cortex of ALS patients revealed the existence of immunopositive fungal antigens comprising punctate bodies in the cytoplasm of some neurons. Fungal DNA was also detected in brain tissue using PCR analysis, uncovering the presence of several fungal species. Finally, proteomic analyses of brain tissue demonstrated the occurrence of several fungal peptides. Collectively, our observations provide compelling evidence of fungal infection in the ALS patients analyzed, suggesting that this infection may play a part in the etiology of the disease or may constitute a risk factor for these patients.

Clinical Trial Designs in Amyotrophic Lateral Sclerosis: Does One Design Fit All?

The last 2 decades have seen a surge in the number of amyotrophic lateral sclerosis (ALS) clinical trials with the hope of finding successful treatments. Clinical trialists aim to repurpose existing drugs and test novel compounds to target potential ALS disease pathophysiology. Recent technological advancements have led to the discovery of new causative genetic agents and modes of delivering potential therapy, calling for increasingly sophisticated trial design. The standard ALS clinical trial design may be modified depending on study needs: type of therapy; route of therapy delivery; phase of therapy development; applicable subpopulation; market availability of therapy; and utility of telemedicine. Novel biomarkers of diagnostic, predictive, prognostic, and pharmacodynamic value are undergoing development and validation for use in clinical trials. Design modifications build on the traditional clinical trial design and may be employed in either the learning or confirming trial phase. Novel designs aim to minimize patient risk, study duration, and sample size, while improving efficiency and promoting statistical power to herald an exciting era for clinical research in ALS.

Protective and Toxic Neuroinflammation in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a clinically heterogeneous disorder characterized by loss of motor neurons, resulting in paralysis and death. Multiple mechanisms of motor neuron injury have been implicated based upon the more than 20 different genetic causes of familial ALS. These inherited mutations compromise diverse motor neuron pathways leading to cell-autonomous injury. In the ALS transgenic mouse models, however, motor neurons do not die alone. Cell death is noncell-autonomous dependent upon a well orchestrated dialogue between motor neurons and surrounding glia and adaptive immune cells. The pathogenesis of ALS consists of 2 stages: an early neuroprotective stage and a later neurotoxic stage. During early phases of disease progression, the immune system is protective with glia and T cells, especially M2 macrophages/microglia, and T helper 2 cells and regulatory T cells, providing anti-inflammatory factors that sustain motor neuron viability. As the disease progresses and motor neuron injury accelerates, a second rapidly progressing phase develops, characterized by M1 macrophages/microglia, and proinflammatory T cells. In rapidly progressing ALS patients, as in transgenic mice, neuroprotective regulatory T cells are significantly decreased and neurotoxicity predominates. Our own therapeutic efforts are focused on modulating these neuroinflammatory pathways. This review will focus on the cellular players involved in neuroinflammation in ALS and current therapeutic strategies to enhance neuroprotection and suppress neurotoxicity with the goal of arresting the progressive and devastating nature of ALS.

A Novel F45S SOD1 Mutation in Amyotrophic Lateral Sclerosis Coexisting with Bullous Pemphigoid

Background

The coexistence of an autoimmune disease and amyotrophic lateral sclerosis (ALS) has led to the hypothesis that immune-mediated pathological mechanisms are overlapping in the two diseases. We report herein a rare coexistence of bullous pemphigoid (BP) in a novel mutation (F45S) of the gene encoding Cu/Zn superoxide dismutase (SOD1) in an ALS patient, and discuss a role for the SOD1 mutation in this unusual overlap.

Case Report

A 57-year-old male with familial ALS, including vesicles and tense bullae on erythematous bases, was diagnosed with BP. Direct immunofluorescence revealed deposits of C3 and immunoglobulin G in the basement membrane zone. Direct sequencing of SOD1 in the patient revealed a novel mutation (c.137T>C; F45S).

Conclusions

We report a novel SOD1 mutation in ALS, which was combined with BP. This novel SOD1 mutation could affect the phenotype of a combined autoimmune disease and matrix metalloproteinase-9. There may therefore be common factors linking BP and ALS with the SOD1 mutation.

Effect of thymic stimulation of CD4+ T cell expansion on disease onset and progression in mutant SOD1 mice

BACKGROUND

The peripheral immune system is implicated in modulating microglial activation, neurodegeneration and disease progression in amyotrophic lateral sclerosis (ALS). Specifically, there is reduced thymic function and regulatory T cell (Treg) number in ALS patients and mutant superoxide dismutase 1 (SOD1) mice, while passive transfer of Tregs ameliorates disease in mutant SOD1 mice. Here, we assessed the effects of augmenting endogenous CD4+ T cell number by stimulating the thymus using surgical castration on the phenotype of transgenic SOD1(G93A) mice.

METHOD

Male SOD1(G93A) mice were castrated or sham operated, and weight loss, disease onset and progression were examined. Thymus atrophy and blood CD4+, CD8+ and CD4+ FoxP3+ T cell numbers were determined by fluorescence activated cell sorting (FACS). Motor neuron counts, glial cell activation and androgen receptor (AR) expression in the spinal cord were investigated using immunohistochemistry and Western blotting. Differences between castrated and sham mice were analysed using an unpaired t test or one-way ANOVA.

RESULTS

Castration significantly increased thymus weight and total CD4+ T cell numbers in SOD1(G93A) mice, although Tregs levels were not affected. Despite this, disease onset and progression were similar in castrated and sham SOD1(G93A) mice. Castration did not affect motor neuron loss or astrocytic activation in spinal cords of SOD1(G93A) mice; however, microglial activation was reduced, specifically M1 microglia. We also show that AR is principally expressed in spinal motor neurons and progressively downregulated in spinal cords of SOD1(G93A) mice from disease onset which is further enhanced by castration.

CONCLUSIONS

These results demonstrate that increasing thymic function and CD4+ T cell number by castration confers no clinical benefit in mutant SOD1 mice, which may reflect an inability to stimulate neuroprotective Tregs. Nonetheless, castration decreases M1 microglial activation in the spinal cord without any clinical improvement and motor neuron rescue, in contrast to other approaches to suppress microglia in mutant SOD1 mice. Lastly, diminished AR expression in spinal motor neurons, which links to another motor neuron disorder, spinal bulbar muscular atrophy (SBMA), may contribute to ALS pathogenesis and suggests a common disease pathway in ALS and SBMA mediated by disruption of AR signalling in motor neurons.

Development of stage-dependent glycans on the Fc domains of IgG antibodies of ALS animals

We recently revealed a unique glycan on the Fc domain of IgG antibodies in ALS patients that mediates antibody-dependent cell cytotoxicity (ADCC). This glycan has a bi-antennary structure that lacks the core fucose and sialic acid residues but contains a bisecting GlcNAc (A2BG2). Little is known, however, about the incidence of A2BG2 expression and IgG cytotoxicity under ALS conditions within well-defined clinical stages. Here, we characterize the IgG antibodies produced in ALS Tg mice by detecting intra- and extra-cellular antigens of motor neurons that express different glycan patterns during the disease. The increased number of innate immune cells found at the disease onset was insufficient to induce an optimal systemic T-cell response. Nevertheless, IgG antibodies were produced against intracellular antigens at the pre-symptomatic stage in the secondary lymphoid organs under the conditions of a poor systemic immune response. Moreover, while the glycosyltransferases of plasma B-cells that synthesize the Fc-glycans were regulated by IL-2 or IL-4, the observed glycosyltransferase pattern did not match that found in ALS Tg mice. We further found that A2BG2 glycan is specific for ALS, its quantity increased with disease progression and that the IgG antibodies identifying extracellular motor neuron antigens were developed at the final stage of the disease. Therefore, the most effective ADCC of motor neurons was observed at the end stage of the disease. We conclude that in ALS, IgG antibodies are produced despite the poor systemic immune response and that the frequency and quantity of A2BG2 glycan expression on the Fc domain depends on the clinical stage. Therefore, A2BG2 is a potential prognostic biomarker for ALS.

Early-stage treatment with Withaferin A reduces levels of misfolded superoxide dismutase 1 and extends lifespan in a mouse model of amyotrophic lateral sclerosis

Approximately 20% of cases of familial amyotrophic lateral sclerosis (ALS) are caused by mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1). Recent studies have shown that Withaferin A (WA), an inhibitor of nuclear factor-kappa B activity, was efficient in reducing disease phenotype in a TAR DNA binding protein 43 transgenic mouse model of ALS. These findings led us to test WA in mice from 2 transgenic lines expressing different ALS-linked SOD1 mutations, SOD1(G93A) and SOD1(G37R). Intraperitoneal administration of WA at a dosage of 4 mg/kg of body weight was initiated from postnatal day 40 until end stage in SOD1(G93A) mice, and from 9 months until end stage in SOD1(G37R) mice. The beneficial effects of WA in the SOD1(G93A) mice model were accompanied by an alleviation of neuroinflammation, a decrease in levels of misfolded SOD1 species in the spinal cord, and a reduction in loss of motor neurons resulting in delayed disease progression and mortality. Interestingly, WA treatment triggered robust induction of heat shock protein 25 (a mouse ortholog of heat shock protein 27), which may explain the reduced level of misfolded SOD1 species in the spinal cord of SOD1(G93A) mice and the decrease of neuronal injury responses, as revealed by real-time imaging of biophotonic SOD1(G93A) mice expressing a luciferase transgene under the control of the growth-associated protein 43 promoter. These results suggest that WA may represent a potential lead compound for drug development aiming to treat ALS.

TDP-43 pathology in the basal forebrain and hypothalamus of patients with amyotrophic lateral sclerosis

Introduction

Amyotrophic lateral sclerosis is a neurodegenerative disease characterized clinically by motor symptoms including limb weakness, dysarthria, dysphagia, and respiratory compromise, and pathologically by inclusions of transactive response DNA-binding protein 43 kDa (TDP-43). Patients with amyotrophic lateral sclerosis also may demonstrate non-motor symptoms and signs of autonomic and energy dysfunction as hypermetabolism and weight loss that suggest the possibility of pathology in the forebrain, including hypothalamus. However, this region has received little investigation in amyotrophic lateral sclerosis. In this study, the frequency, topography, and clinical associations of TDP-43 inclusion pathology in the basal forebrain and hypothalamus were examined in 33 patients with amyotrophic lateral sclerosis: 25 men and 8 women; mean age at death of 62.7 years, median disease duration of 3.1 years (range of 1.3 to 9.8 years).

Results

TDP-43 pathology was present in 11 patients (33.3%), including components in both basal forebrain (n= 10) and hypothalamus (n= 7). This pathology was associated with non-motor system TDP-43 pathology (Χ²= 17.5, p= 0.00003) and bulbar symptoms at onset (Χ²= 4.04, p= 0.044), but not age or disease duration. Furthermore, TDP-43 pathology in the lateral hypothalamic area was associated with reduced body mass index (W= 11, p= 0.023).

Conclusions

This is the first systematic demonstration of pathologic involvement of the basal forebrain and hypothalamus in amyotrophic lateral sclerosis. Furthermore, the findings suggest that involvement of the basal forebrain and hypothalamus has significant phenotypic associations in amyotrophic lateral sclerosis, including site of symptom onset, as well as deficits in energy metabolism with loss of body mass index.

T-cell-mediated regulation of neuroinflammation involved in neurodegenerative diseases

Neuroinflammation is involved in several neurodegenerative disorders and emerging evidence indicates that it constitutes a critical process that is required for the progression of neurodegeneration. Microglial activation constitutes a central event in neuroinflammation. Furthermore, microglia can not only be activated with an inflammatory and neurotoxic phenotype (M1-like phenotype), but they also can acquire a neurosupportive functional phenotype (M2-like phenotype) characterised by the production of anti-inflammatory mediators and neurotrophic factors. Importantly, during the past decade, several studies have shown that CD4⁺ T-cells infiltrate the central nervous system (CNS) in many neurodegenerative disorders, in which their participation has a critical influence on the outcome of microglial activation and consequent neurodegeneration. In this review, we focus on the analysis of the interplay of the different sub-populations of CD4⁺ T-cells infiltrating the CNS and how they participate in regulating the outcome of neuroinflammation and neurodegeneration in the context of Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis and multiple sclerosis. In this regard, encephalitogenic inflammatory CD4⁺ T-cells, such as Th1, Th17, GM-CSF-producer CD4⁺ T-cells and γδT-cells, strongly contribute to chronic neuroinflammation, thus perpetuating neurodegenerative processes. In contrast, encephalitogenic or meningeal Tregs and Th2 cells decrease inflammatory functions in microglial cells and promote a neurosupportive microenvironment. Moreover, whereas some neurodegenerative disorders such as multiple sclerosis, Parkinson’s disease and Alzheimer’s disease involve the participation of inflammatory CD4⁺ T-cells 'naturally', the physiopathology of other neurodegenerative diseases, such as amyotrophic lateral sclerosis, is associated with the participation of anti-inflammatory CD4⁺ T-cells that delay the neurodegenerative process. Thus, current evidence supports the hypothesis that the involvement of CD4⁺ T-cells against CNS antigens constitutes a key component in regulating the progression of the neurodegenerative process.

Dual destructive and protective roles of adaptive immunity in neurodegenerative disorders

Inappropriate T cell responses in the central nervous system (CNS) affect the pathogenesis of a broad range of neuroinflammatory and neurodegenerative disorders that include, but are not limited to, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer’s disease and Parkinson’s disease. On the one hand immune responses can exacerbate neurotoxic responses; while on the other hand, they can lead to neuroprotective outcomes. The temporal and spatial mechanisms by which these immune responses occur and are regulated in the setting of active disease have gained significant recent attention. Spatially, immune responses that affect neurodegeneration may occur within or outside the CNS. Migration of antigen-specific CD4+ T cells from the periphery to the CNS and consequent immune cell interactions with resident glial cells affect neuroinflammation and neuronal survival. The destructive or protective mechanisms of these interactions are linked to the relative numerical and functional dominance of effector or regulatory T cells. Temporally, immune responses at disease onset or during progression may exhibit a differential balance of immune responses in the periphery and within the CNS. Immune responses with predominate T cell subtypes may differentially manifest migratory, regulatory and effector functions when triggered by endogenous misfolded and aggregated proteins and cell-specific stimuli. The final result is altered glial and neuronal behaviors that influence the disease course. Thus, discovery of neurodestructive and neuroprotective immune mechanisms will permit potential new therapeutic pathways that affect neuronal survival and slow disease progression.

The role of the immune system in neurodegenerative disorders: Adaptive or maladaptive?

Neurodegenerative diseases share common features, including catastrophic neuronal loss that leads to cognitive or motor dysfunction. Neuronal injury occurs in an inflammatory milieu that is populated by resident and sometimes, infiltrating, immune cells - all of which participate in a complex interplay between secreted inflammatory modulators and activated immune cell surface receptors. The importance of these immunomodulators is highlighted by the number of immune factors that have been associated with increased risk of neurodegeneration in recent genome-wide association studies. One of the more difficult tasks for designing therapeutic strategies for immune modulation against neurodegenerative diseases is teasing apart beneficial from harmful signals. In this regard, learning more about the immune components of these diseases has yielded common themes. These unifying concepts should eventually enable immune-based therapeutics for treatment of Alzheimer׳s and Parkinson׳s diseases and amyotrophic lateral sclerosis. Targeted immune modulation should be possible to temper maladaptive factors, enabling beneficial immune responses in the context of neurodegenerative diseases. This article is part of a Special Issue entitled SI: Neuroimmunology in Health And Disease.

Lymphocytes and autoimmunity after spinal cord injury

Over the past 15 years an immense amount of data has accumulated regarding the infiltration and activation of lymphocytes in the traumatized spinal cord. Although the impact of the intraspinal accumulation of lymphocytes is still unclear, modulation of the adaptive immune response via active and passive vaccination is being evaluated for its preclinical efficacy in improving the outcome for spinal-injured individuals. The complexity of the interaction between the nervous and the immune systems is highlighted in the contradictions that appear in response to these modulations. Current evidence regarding augmentation and inhibition of the adaptive immune response to spinal cord injury is reviewed with an aim toward reconciling conflicting data and providing consensus issues that may be exploited in future therapies. Opportunities such an approach may provide are highlighted as well as the obstacles that must be overcome before such approaches can be translated into clinical trials.

The immunomodulatory effects of human mesenchymal stem cells on peripheral blood mononuclear cells in ALS patients

In a previous study, we reported that intrathecal injection of mesenchymal stem cells (MSCs) slowed disease progression in G93A mutant superoxide dismutase1 transgenic mice. In this study, we found that intrathecal MSC administration vastly increased the infiltration of peripheral immune cells into the spinal cord of Amyotrophic lateral sclerosis (ALS) mice (G93A mutant superoxide dismutase1 transgenic). Thus, we investigated the immunomodulatory effect of MSCs on peripheral blood mononuclear cells (PBMCs) in ALS patients, focusing on regulatory T lymphocytes (Treg ; CD4(+) /CD25(high) /FoxP3(+) ) and the mRNA expression of several cytokines (IFN-γ, TNF-α, IL-17, IL-4, IL-10, IL-13, and TGF-β). Peripheral blood samples were obtained from nine healthy controls (HC) and sixteen patients who were diagnosed with definite or probable ALS. Isolated PBMCs from the blood samples of all subjects were co-cultured with MSCs for 24 or 72 h. Based on a fluorescence-activated cell sorting analysis, we found that co-culture with MSCs increased the Treg /total T-lymphocyte ratio in the PBMCs from both groups according to the co-culture duration. Co-culture of PBMCs with MSCs for 24 h led to elevated mRNA levels of IFN-γ and IL-10 in the PBMCs from both groups. However, after co-culturing for 72 h, although the IFN-γ mRNA level had returned to the basal level in co-cultured HC PBMCs, the IFN-γ mRNA level in co-cultured ALS PBMCs remained elevated. Additionally, the levels of IL-4 and TGF-β were markedly elevated, along with Gata3 mRNA, a Th2 transcription factor mRNA, in both HC and ALS PBMCs co-cultured for 72 h. The elevated expression of these cytokines in the co-culture supernatant was confirmed via ELISA. Furthermore, we found that the increased mRNA level of indoleamine 2,3-dioxygenase (IDO) in the co-cultured MSCs was correlated with the increase in Treg induction. These findings of Treg induction and increased anti-inflammatory cytokine expression in co-cultured ALS PBMCs provide indirect evidence that MSCs may play a role in the immunomodulation of inflammatory responses when MSC therapy is targeted to ALS patients. We propose the following mechanism for the effect of mesenchymal stem cells (MSCs) administered intrathecally in amyotrophic lateral sclerosis (ALS): MSCs increase infiltration of peripheral immune cells into CNS and skew the infiltrated immune cells toward regulatory T lymphocytes (Treg ) and Th2 lymphocytes. Treg and Th2 secret anti-inflammatory cytokines such as IL-4, IL-10, and TGF-β. A series of immunomodulatory mechanism provides a new strategy for ALS treatment.

Glial cells in amyotrophic lateral sclerosis

For more than twenty years glial cells have been implicated in the pathogenetic cascades for genetic and sporadic forms of ALS. The biological role of glia, including the principal CNS glia, astroglia and oligodendroglia, as well as the myeloid derived microglia, has uniformly led to converging data sets that implicate these diverse cells in the degeneration of neurons in ALS. Originating as studies in postmortem human brain implicating astroglia, the research progressed to strongly implicate microglia and contributors to CNS injury in all forms of ALS. Most recently and unexpectedly, oligodendroglia have also been shown in animal model systems and human brain to play an early role in the dysfunction and death of ALS neurons. These studies have identified a number of diverse cellular cascades that could be, or have already been, the target of therapeutic interventions. Understanding the temporal and regional role of these cells and the magnitude of their contribution will be important for future interventions. Employing markers of these cell types may also allow for future important patient subgrouping and pharmacodynamic drug development tools.

The dopaminergic system in autoimmune diseases

Bidirectional interactions between the immune and the nervous systems are of considerable interest both for deciphering their functioning and for designing novel therapeutic strategies. The past decade has brought a burst of insights into the molecular mechanisms involved in neuroimmune communications mediated by dopamine. Studies of dendritic cells (DCs) revealed that they express the whole machinery to synthesize and store dopamine, which may act in an autocrine manner to stimulate dopamine receptors (DARs). Depending on specific DARs stimulated on DCs and T cells, dopamine may differentially favor CD4⁺ T cell differentiation into Th1 or Th17 inflammatory cells. Regulatory T cells can also release high amounts of dopamine that acts in an autocrine DAR-mediated manner to inhibit their suppressive activity. These dopaminergic regulations could represent a driving force during autoimmunity. Indeed, dopamine levels are altered in the brain of mouse models of multiple sclerosis (MS) and lupus, and in inflamed tissues of patients with inflammatory bowel diseases or rheumatoid arthritis (RA). The distorted expression of DARs in peripheral lymphocytes of lupus and MS patients also supports the importance of dopaminergic regulations in autoimmunity. Moreover, dopamine analogs had beneficial therapeutic effects in animal models, and in patients with lupus or RA. We propose models that may underlie key roles of dopamine and its receptors in autoimmune diseases.

The widening spectrum of C9ORF72-related disease; genotype/phenotype correlations and potential modifiers of clinical phenotype

The GGGGCC (G4C2) repeat expansion in C9ORF72 is the most common cause of familial amyotrophic lateral sclerosis (ALS), frontotemporal lobar dementia (FTLD) and ALS-FTLD, as well as contributing to sporadic forms of these diseases. Screening of large cohorts of ALS and FTLD cohorts has identified that C9ORF72-ALS is represented throughout the clinical spectrum of ALS phenotypes, though in comparison with other genetic subtypes, C9ORF72 carriers have a higher incidence of bulbar onset disease. In contrast, C9ORF72-FTLD is predominantly associated with behavioural variant FTD, which often presents with psychosis, most commonly in the form of hallucinations and delusions. However, C9ORF72 expansions are not restricted to these clinical phenotypes. There is a higher than expected incidence of parkinsonism in ALS patients with C9ORF72 expansions, and the G4C2 repeat has also been reported in other motor phenotypes, such as primary lateral sclerosis, progressive muscular atrophy, corticobasal syndrome and Huntington-like disorders. In addition, the expansion has been identified in non-motor phenotypes including Alzheimer's disease and Lewy body dementia. It is not currently understood what is the basis of the clinical variation seen with the G4C2 repeat expansion. One potential explanation is repeat length. Sizing of the expansion by Southern blotting has established that there is somatic heterogeneity, with different expansion lengths in different tissues, even within the brain. To date, no correlation with expansion size and clinical phenotype has been established in ALS, whilst in FTLD only repeat size in the cerebellum was found to correlate with disease duration. Somatic heterogeneity suggests there is a degree of instability within the repeat and evidence of anticipation has been reported with reducing age of onset in subsequent generations. This variability/instability in expansion length, along with its interactions with environmental and genetic modifiers, such as TMEM106B, may be the basis of the differing clinical phenotypes arising from the mutation.

The multifaceted role of glial cells in amyotrophic lateral sclerosis

Despite indisputable progress in the molecular and genetic aspects of amyotrophic lateral sclerosis (ALS), a mechanistic comprehension of the neurodegenerative processes typical of this disorder is still missing and no effective cures to halt the progression of this pathology have yet been developed. Therefore, it seems that a substantial improvement of the outcome of ALS treatments may depend on a better understanding of the molecular mechanisms underlying neuronal pathology and survival as well as on the establishment of novel etiological therapeutic strategies. Noteworthy, a convergence of recent data from multiple studies suggests that, in cellular and animal models of ALS, a complex pathological interplay subsists between motor neurons and their non-neuronal neighbours, particularly glial cells. These observations not only have drawn attention to the physiopathological changes glial cells undergo during ALS progression, but they have moved the focus of the investigations from intrinsic defects and weakening of motor neurons to glia-neuron interactions. In this review, we summarize the growing body of evidence supporting the concept that different glial populations are critically involved in the dreadful chain of events leading to motor neuron sufferance and death in various forms of ALS. The outlined observations strongly suggest that glial cells can be the targets for novel therapeutic interventions in ALS.

Neuroimmunity dynamics and the development of therapeutic strategies for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disorder characterized by the progressive and selective loss of both upper and lower motoneurons. The neurodegenerative process is accompanied by a sustained inflammation in the brain and spinal cord. The neuron-immune interaction, implicating resident microglia of the central nervous system and blood-derived immune cells, is highly dynamic over the course of the disease. Here, we discuss the timely controlled neuroprotective and neurotoxic cues that are provided by the immune environment of motoneurons and their potential therapeutic applications for ALS.

Whole-blood global DNA methylation is increased in amyotrophic lateral sclerosis independently of age of onset

ALS is a heterogeneous disease that is not well understood. Epigenetic rearrangements are important in complex disorders including motor neuron diseases. The aim of this study was to determine whether whole-blood DNA methylation (DNA MET %) is a potential modifier of age at onset in ALS. DNA MET % was measured as incorporation of [(3)H]dCTP following HpaII cut in 96 ALS patients and 87 controls, comprising: early-onset (< 55 years of age) and late-onset (> 74 years of age). Methionine (Met) and homocysteine (Hcy) plasma levels were assessed by liquid chromatography selected reaction monitoring coupled with isotope-dilution mass spectrometry. Results showed that DNA MET % was increased in ALS patients independently of age of onset. Compared to the other three groups, Hcy plasma levels were reduced in early-onset ALS patients but Met levels were similar. ROC analysis reported Met levels and DNA MET %, respectively, with a slight and moderate discriminative power. In conclusion, increased DNA MET % is a possible marker of epigenetic dysfunction in ALS independently of age of onset. Further studies dissecting biological determinants of phenotypic complexity in ALS may help in developing successful therapeutic strategies.

The innate and adaptive immunological aspects in neurodegenerative diseases

Neurodegenerative diseases affect a considerable percentage of the elderly population. New therapeutic approaches are warranted, aiming to at least delay and possibly reverse disease progression. Strategies to elaborate such approaches require knowledge of specific immune system involvement in disease pathogenesis. In this review, innate and adaptive immunological aspects of neurodegenerative disorders, in particular Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis (ALS), are discussed. Initiating disease factors, as well as common mechanistic pathways, are detailed and potential immunological therapeutic targets are identified.

Dysregulation of the complement cascade in the hSOD1G93A transgenic mouse model of amyotrophic lateral sclerosis

Background

Components of the innate immune complement system have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS); however, a comprehensive examination of complement expression in this disease has not been performed. This study therefore aimed to determine the expression of complement components (C1qB, C4, factor B, C3/C3b, C5 and CD88) and regulators (CD55 and CD59a) in the lumbar spinal cord of hSOD1^G93A mice during defined disease stages.

Methods

hSOD1^G93A and wild-type mice were examined at four different ages of disease progression. mRNA and protein expression of complement components and regulators were examined using quantitative PCR, western blotting and ELISA. Localisation of complement components within lumbar spinal cord was investigated using immunohistochemistry. Statistical differences between hSOD1^G93A and wild-type mice were analysed using a two-tailed t-test at each stage of disease progression.

Results

We found several early complement factors increased as disease progressed, whilst complement regulators decreased; suggesting overall increased complement activation through the classical or alternative pathways in hSOD1^G93A mice. CD88 was also increased during disease progression, with immunolocalisation demonstrating expression on motor neurons and increasing expression on microglia surrounding the regions of motor neuron death.

Conclusions

These results indicate that local complement activation and increased expression of CD88 may contribute to motor neuron death and ALS pathology in the hSOD1^G93A mouse. Hence, reducing complement-induced inflammation could be an important therapeutic strategy to treat ALS.

Vaccination with heat-shocked mononuclear cells as a strategy for treating neurodegenerative disorders driven by microglial inflammation

Naturally occurring T regulatory cells targeting epitopes derived from various heat shock proteins escape thymic negative selection and can be activated by vaccination with heat shock proteins; hence, vaccination with such proteins has exerted favorable effects on rodent models of autoimmune disorders. A more elegant way to achieve such vaccination, first evaluated clinically by Al-Harbi in the early 1990s, is to subject mononuclear cells to survivable heat shock ex vivo, incubate them at physiological temperature for a further 24-48 h, and then inject them subcutaneously; anecdotally, beneficial effects were observed with this strategy in a wide range of autoimmune and inflammatory conditions. There is growing evidence that M1-activated microglia play a primary or secondary role in the pathogenesis of numerous neurodegenerative diseases, as well as in major depression. T regulatory cells, by polarizing microglial toward a reparative M2 phenotype, have the potential to aid control of such disorders. It would be appropriate to test the heat-shocked mononuclear cell vaccination strategy in animal models of neurodegeneration and major depression, and to evaluate this approach clinically if such studies yield encouraging results.