Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment. Here we report the results of a moderate-scale sequencing study aimed at identifying new genes contributing to predisposition for ALS. We performed whole exome sequencing of 2,874 ALS patients and compared them to 6,405 controls. Several known ALS genes were found to be associated, and the non-canonical IκB kinase family TANK-Binding Kinase 1 (TBK1) was identified as an ALS gene. TBK1 is known to bind to and phosphorylate a number of proteins involved in innate immunity and autophagy, including optineurin (OPTN) and p62 (SQSTM1/sequestosome), both of which have also been implicated in ALS. These observations reveal a key role of the autophagic pathway in ALS and suggest specific targets for therapeutic intervention.

The most common inherited form of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease affecting adult motoneurons, is caused by dominant mutations in the ubiquitously expressed Cu 2؉ ͞Zn 2؉ superoxide dismutase (SOD1). Recent studies suggest that glia may contribute to motoneuron injury in animal models of familial ALS. To determine whether the expression of mutant SOD1 (mSOD1 G93A ) in CNS microglia contributes to motoneuron injury, PU.1 ؊/؊ mice that are unable to develop myeloid and lymphoid cells received bone marrow transplants resulting in donor-derived microglia. Donor-derived microglia from mice overexpressing mSOD1 G93A , an animal model of familial ALS, transplanted into PU.1 ؊/؊ mice could not induce weakness, motoneuron injury, or an ALS-like disease. To determine whether expression of mSOD1 G93A in motoneurons and astroglia, as well as microglia, was required to produce motoneuron disease, PU.1 ؊/؊ mice were bred with mSOD1 G93A mice. In mSOD1 G93A ͞PU.1 ؊/؊ mice, wild-type donorderived microglia slowed motoneuron loss and prolonged disease duration and survival when compared with mice receiving mSOD1 G93A expressing cells or mSOD1 G93A mice. In vitro studies confirmed that wild-type microglia were less neurotoxic than similarly cultured mSOD1 G93A microglia. Compared with wild-type microglia, mSOD1 G93A microglia produced and released more superoxide and nitrite؉nitrate, and induced more neuronal death. These data demonstrate that the expression of mSOD1 G93A results in activated and neurotoxic microglia, and suggests that the lack of mSOD1 G93A expression in microglia may contribute to motoneuron protection. This study confirms the importance of microglia as a double-edged sword, and focuses on the importance of targeting microglia to minimize cytotoxicity and maximize neuroprotection in neurodegenerative diseases.bone marrow transplant ͉ neuroprotection ͉ superoxide dismutase ͉ nitric oxide ͉ motoneurons

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These data confirm the presence of cognitive impairment in 50% of patients with ALS and particularly implicate executive dysfunction and mild memory decline in the disease process. More severe impairment occurs in a subset of patients with ALS and has features consistent with FTD.

Neuroinflammation, marked by gliosis and infiltrating T cells, is a prominent pathological feature in diverse models of dominantly inherited neurodegenerative diseases. Recent evidence derived from transgenic mice ubiquitously overexpressing mutant Cu 2؉ / Zn 2؉ superoxide dismutase (mSOD1), a chronic neurodegenerative model of inherited amyotrophic lateral sclerosis (ALS), indicates that glia with either a lack of or reduction in mSOD1 expression enhance motoneuron protection and slow disease progression. However, the contribution of T cells that are present at sites of motoneuron injury in mSOD1 transgenic mice is not known. Here we show that when mSOD1 mice were bred with mice lacking functional T cells or CD4؉ T cells, motoneuron disease was accelerated, accompanied by unexpected attenuated morphological markers of gliosis, increased mRNA levels for proinflammatory cytokines and NOX2, and decreased levels of trophic factors and glial glutamate transporters. Bone marrow transplants reconstituted mice with T cells, prolonged survival, suppressed cytotoxicity, and restored glial activation. These results demonstrate for the first time in a model of chronic neurodegeneration that morphological activation of microglia and astroglia does not predict glial function, and that the presence of CD4؉ T cells provides supportive neuroprotection by modulating the trophic/cytotoxic balance of glia. These glial/T-cell interactions establish a novel target for therapeutic intervention in ALS and possibly other neurodegenerative diseases.amyotrophic lateral sclerosis ͉ astrocytes ͉ bone marrow transplant ͉ microglia ͉ superoxide dismutase

Amyotrophic lateral sclerosis is a relentless and devastating adult-onset neurodegenerative disease with no known cure. In mice with amyotrophic lateral sclerosis, CD4+ T lymphocytes and wild-type microglia potentiate protective inflammatory responses and play a principal role in disease pathoprogression. Using this model, we demonstrate that endogenous T lymphocytes, and more specifically regulatory T lymphocytes, are increased at early slowly progressing stages, augmenting interleukin-4 expression and protective M2 microglia, and are decreased when the disease rapidly accelerates, possibly through the loss of FoxP3 expression in the regulatory T lymphocytes. Without ex vivo activation, the passive transfer of wild-type CD4+ T lymphocytes into amyotrophic lateral sclerosis mice lacking functional T lymphocytes lengthened disease duration and prolonged survival. The passive transfer of endogenous regulatory T lymphocytes from early disease stage mutant Cu2+/Zn2+ superoxide dismutase mice into these amyotrophic lateral sclerosis mice, again without ex vivo activation, were substantially more immunotherapeutic sustaining interleukin-4 levels and M2 microglia, and resulting in lengthened disease duration and prolonged survival; the stable disease phase was extended by 88% using mutant Cu2+/Zn2+ superoxide dismutase regulatory T lymphocytes. A potential mechanism for this enhanced life expectancy may be mediated by the augmented secretion of interleukin-4 from mutant Cu2+/Zn2+ superoxide dismutase regulatory T lymphocytes that directly suppressed the toxic properties of microglia; flow cytometric analyses determined that CD4+/CD25+/FoxP3+ T lymphocytes co-expressed interleukin-4 in the same cell. These observations were extended into the amyotrophic lateral sclerosis patient population where patients with more rapidly progressing disease had decreased numbers of regulatory T lymphocytes; the numbers of regulatory T lymphocytes were inversely correlated with disease progression rates. These data suggest a cellular mechanism whereby endogenous regulatory T lymphocytes are immunocompetent and actively contribute to neuroprotection through their interactions with microglia. Furthermore, these data suggest that immunotherapeutic interventions must begin early in the pathogenic process since immune dysfunction occurs at later stages. Thus, the cumulative mouse and human amyotrophic lateral sclerosis data suggest that increasing the levels of regulatory T lymphocytes in patients with amyotrophic lateral sclerosis at early stages in the disease process may be of therapeutic value, and slow the rate of disease progression and stabilize patients for longer periods of time.

Objective To evaluate the safety, tolerability, and pharmacokinetics of an antisense oligonucleotide designed to inhibit SOD1 expression (ISIS 333611) following intrathecal administration in patients with SOD1-related familial amyotrophic lateral sclerosis (ALS). Background Mutations in SOD1 cause 13% of familial ALS. In animal studies, ISIS 333611 delivered to the cerebrospinal fluid (CSF) distributed to the brain and spinal cord, decreased SOD1 mRNA and protein levels in spinal cord tissue, and prolonged survival in the SOD1G93A rat ALS model. Methods In a randomized, placebo controlled Phase 1 trial, ISIS 333611 was delivered by intrathecal infusion using an external pump over 11.5 hours at increasing doses to four cohorts of eight SOD1 positive ALS subjects (randomized 6 drug: 2 placebo/cohort). Subjects were allowed to re-enroll in subsequent cohorts. Safety and tolerability assessments were made during the infusion and periodically over 28 days following the infusion. CSF and plasma drug levels were measured. Findings No dose-limiting toxicities were identified at doses up to 3.0 mg. No safety or tolerability concerns related to ISIS 333611 were identified. There were no serious adverse events (AEs) in ISIS 333611-treated subjects. Re-enrollment and re-dosing of subjects with ISIS 333611 was also well tolerated. Dose-dependent CSF and plasma concentrations were observed. Interpretation In this first clinical study to report intrathecal delivery of an antisense oligonucleotide, ISIS 333611 was well tolerated when administered as an intrathecal infusion in subjects with SOD1 familial ALS. CSF and plasma drug levels were consistent with levels predicted from preclinical studies. These results suggest that antisense oligonucleotide delivery to the central nervous system may be a feasible therapeutic strategy for neurological disorders. Source of funding ALS Association, Muscular Dystrophy Association, Isis Pharmaceuticals

To identify novel genes associated with ALS, we undertook two lines of investigation. We carried out a genome-wide association study comparing 20,806 ALS cases and 59,804 controls. Independently, we performed a rare variant burden analysis comparing 1,138 index familial ALS cases and 19,494 controls. Through both approaches, we identified kinesin family member 5A (KIF5A) as a novel gene associated with ALS. Interestingly, mutations predominantly in the N-terminal motor domain of KIF5A are causative for two neurodegenerative diseases: hereditary spastic paraplegia (SPG10) and Charcot-Marie-Tooth type 2 (CMT2). In contrast, ALS-associated mutations are primarily located at the C-terminal cargo-binding tail domain and patients harboring loss-of-function mutations displayed an extended survival relative to typical ALS cases. Taken together, these results broaden the phenotype spectrum resulting from mutations in KIF5A and strengthen the role of cytoskeletal defects in the pathogenesis of ALS.