Monoclonal full-length antibody against TAR DNA binding protein 43 reduces related proteinopathy in neurons.

Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), 2 incurable neurodegenerative disorders, share the same pathological hallmark named TDP43 (TAR DNA binding protein 43) proteinopathy. This event is characterized by a consistent cytoplasmic mislocalization and aggregation of the protein TDP43, which loses its physiological properties, leading neurons to death. Antibody-based approaches are now emerging interventions in the field of neurodegenerative disorders.

Mitigation of ALS Pathology by Neuron-Specific Inhibition of Nuclear Factor Kappa B Signaling.

To investigate the role of neuronal NF-κB activity in pathogenesis of amyotrophic lateral sclerosis (ALS), we generated transgenic mice with neuron-specific expression of a super-repressor form of the NF-κB inhibitor (IκBα-SR), which were then crossed with mice of both sexes, expressing ALS-linked gene mutants for TAR DNA-binding protein (TDP-43) and superoxide dismutase 1 (SOD1). Remarkably, neuronal expression of IκBα-SR transgene in mice expressing TDP-43 or TDP-43 mice led to a decrease in cytoplasmic to nuclear ratio of human TDP-43. The mitigation of TDP-43 neuropathology by IκBα-SR, which is likely due to an induction of autophagy, was associated with amelioration of cognitive and motor deficits as well as reduction of motor neuron loss and gliosis.

Transmission of ALS pathogenesis by the cerebrospinal fluid.

To test the hypothesis that the cerebrospinal fluid (CSF) could provide a spreading route for pathogenesis of amyotrophic lateral sclerosis (ALS), we have examined the effects of intraventricular infusion during 2 weeks of pooled CSF samples from sporadic ALS patients or control CSF samples into transgenic mice expressing human TDP43 which do not develop pathological phenotypes. Infusion of ALS-CSF, but not of control CSF, triggered motor and cognitive dysfunction, as well as ALS-like pathological changes including TDP43 proteinopathy, neurofilament disorganization and neuroinflammation. In addition, the neuron-specific translational profiles from peptide analyses of immunoprecipitated ribosomes revealed dysregulation of multiple protein networks in response to ALS-CSF altering cytoskeletal organization, vesicle trafficking, mitochondrial function, and cell metabolism.

Virus-mediated delivery of antibody targeting TAR DNA-binding protein-43 mitigates associated neuropathology.

The cytoplasmic aggregation of TAR DNA-binding protein-43 (TDP-43) is a hallmark of degenerating neurons in amyotrophic lateral sclerosis (ALS) and subsets of frontotemporal dementia (FTD). In order to reduce TDP-43 pathology, we generated single-chain (scFv) antibodies against the RNA recognition motif 1 (RRM1) of TDP-43, which is involved in abnormal protein self-aggregation and interaction with p65 NF-κB. Virus-mediated delivery into the nervous system of a scFv antibody, named VH7Vk9, reduced microgliosis in a mouse model of acute neuroinflammation and mitigated cognitive impairment, motor defects, TDP-43 proteinopathy, and neuroinflammation in transgenic mice expressing ALS-linked TDP-43 mutations.

Neuronal Expression of UBQLN2 Exacerbates TDP-43 Pathology in TDP-43 Mice through Interaction with Ubiquitin.

Mutations in the gene encoding ubiquilin-2 (UBQLN2) are linked to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). UBQLN2 plays a central role in ubiquitin proteasome system (UPS) and UBQLN2 up-regulation exacerbates TDP-43 cytoplasmic aggregates. To analyze interaction between UBQLN2 and TDP-43 and to produce a relevant ALS animal model, we have generated a new transgenic mouse expressing UBQLN2 under the neurofilament heavy (NFH) gene promoter.

Exosome secretion is a key pathway for clearance of pathological TDP-43.

Cytoplasmic TDP-43 aggregation is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Here we investigated the role of exosomes in the secretion and propagation of TDP-43 aggregates. TDP-43 was detected in secreted exosomes from Neuro2a cells and primary neurons but not from astrocytes or microglia.

Adeno-associated virus-mediated delivery of a recombinant single-chain antibody against misfolded superoxide dismutase for treatment of amyotrophic lateral sclerosis.

There is emerging evidence that the misfolding of superoxide dismutase 1 (SOD1) may represent a common pathogenic event in both familial and sporadic amyotrophic lateral sclerosis (ALS). To reduce the burden of misfolded SOD1 species in the nervous system, we have tested a novel therapeutic approach based on adeno-associated virus (AAV)-mediated tonic expression of a DNA construct encoding a secretable single-chain fragment variable (scFv) antibody composed of the variable heavy and light chain regions of a monoclonal antibody (D3H5) binding specifically to misfolded SOD1. A single intrathecal injection of the AAV encoding the single-chain antibody in SOD1(G93A) mice at 45 days of age resulted in sustained expression of single-chain antibodies in the spinal cord, and it delayed disease onset and extension of life span by up to 28%, in direct correlation with scFv titers in the spinal cord.

Pathological hallmarks of amyotrophic lateral sclerosis/frontotemporal lobar degeneration in transgenic mice produced with TDP-43 genomic fragments.

Transactive response DNA-binding protein 43 ubiquitinated inclusions are a hallmark of amyotrophic lateral sclerosis and of frontotemporal lobar degeneration with ubiquitin-positive inclusions. Yet, mutations in TARDBP, the gene encoding these inclusions are associated with only 3% of sporadic and familial amyotrophic lateral sclerosis. Recent transgenic mouse studies have revealed a high degree of toxicity due to transactive response DNA-binding protein 43 proteins when overexpressed under the control of strong neuronal gene promoters, resulting in early paralysis and death, but without the presence of amyotrophic lateral sclerosis-like ubiquitinated transactive response DNA-binding protein 43-positive inclusions.