Histopathological Investigation of Progressive Encephalomyelitis with Rigidity and Myoclonus: An Autopsy Case Characterized by Oculomotor Dysfunction and Autonomic Failure.

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a rare disease associated with the presence of anti-glycine receptor (GlyR) antibodies. We herein report an autopsy case of an 80-year-old man diagnosed with anti-GlyR antibody-positive PERM who presented with symptoms of oculomotor dysfunction and autonomic failure. Despite intensive immunotherapy, the neurological symptoms showed almost no improvement, and the patient succumbed to aspiration pneumonia and bacterial translocation. Postmortem pathology revealed mild inflammatory changes and neuronal loss that were disproportionate to a severe clinical presentation. These results suggest that the clinical symptoms of PERM may result from antibody-mediated GlyR internalization, leading to neuronal disinhibition, rather than a neuroinflammatory signature.

Ideal body weight-based determination of minimum oral calories beneficial to function and survival in ALS.

Introduction: This study sought to identify the optimal caloric intake to improve function and survival in ALS patients by comparing oral intake per ideal body weight (IBW) and its discrepancy with total energy expenditure (TEE) using the Shimizu formula. Methods: A retrospective analysis of 104 ALS patients was conducted, categorizing them based on their average intake during the first week after admission using two primary intake cutoffs: 25 kcal/kgIBW and 30 kcal/kgIBW. The variance between oral intake and TEE was also evaluated using -300 kcal and 0 kcal as reference points. Results: Oral caloric intake per IBW and functional decline rate (rs = -0.35, p < 0.001), but the variance from TEE was not significantly correlated (-0.11, p = 0.27). Survival data showed that patients consuming less than 25 kcal/kgIBW had a median survival of 24 months, increasing to 38 months for those consuming between 25-30 kcal/kgIBW and 63 months for those consuming 30 kcal/kgIBW or more. Deviations from the TEE did not significantly affect survival (p = 0.36). Among patients consuming less than their TEE, those consuming less than 25 kcal/kgIBW had a shorter median survival (24 months) compared to their counterparts (46 months) (p = 0.022). Consumption of less than 25 kcal/kgBW emerged as a significant negative predictor of patient outcome, independent of factors such as age, gender or disease progression. Discussion: Intakes of 25 kcal/kgIBW or more are correlated with improved ALS outcomes, and larger, multi-regional studies are recommended for deeper insights.

Efficacy of oligodendrocyte precursor cells as delivery vehicles for single-chain variable fragment to misfolded SOD1 in ALS rat model.

Superoxide dismutase1 (SOD 1) mutation is a leading cause of familial amyotrophic lateral sclerosis (ALS). Growing evidence suggests that antibody therapy against misfolded SOD1 protein can be therapeutic. However, the therapeutic effects are limited, partly because of the delivery system. Therefore, we investigated the efficacy of oligodendrocyte precursor cells (OPCs) as a drug delivery vehicle of single-chain variable fragments (scFv). Using a Borna disease virus vector that is pharmacologically removable and episomally replicable in the recipient cells, we successfully transformed wild-type OPCs to secrete scFv of a novel monoclonal antibody (D3-1), specific for misfolded SOD1. Single intrathecal injection of OPCs scFvD3-1, but not OPCs alone, significantly delayed disease onset and prolonged the lifespan of ALS rat models expressing SOD1 H46R . The effect of OPC scFvD3-1 surpassed that of a 1 month intrathecal infusion of full-length D3-1 antibody alone. scFv-secreting OPCs suppressed neuronal loss and gliosis, reduced levels of misfolded SOD1 in the spinal cord, and suppressed the transcription of inflammatory genes, including Olr1, an oxidized low-density lipoprotein receptor 1. The use of OPCs as a delivery vehicle for therapeutic antibodies is a new option for ALS in which misfolded protein and oligodendrocyte dysfunction are implicated in the pathogenesis.

Spinal cord extracts of amyotrophic lateral sclerosis spread TDP-43 pathology in cerebral organoids.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder caused by progressive loss of motor neurons and there is currently no effective therapy. Cytoplasmic mislocalization and aggregation of TAR DNA-binding protein 43 kDa (TDP-43) within the CNS is a pathological hallmark in sporadic ALS and prion-like propagation of pathogenic TDP-43 is thought to be implicated in disease progression. However, cell-to-cell transmission of pathogenic TDP-43 in the human CNS has not been confirmed experimentally. Here we used induced pluripotent stem cells (iPSCs)-derived cerebral organoids as recipient CNS tissue model that are anatomically relevant human brain. We injected postmortem spinal cord protein extracts individually from three non-ALS or five sporadic ALS patients containing pathogenic TDP-43 into the cerebral organoids to validate the templated propagation and spreading of TDP-43 pathology in human CNS tissue. We first demonstrated that the administration of spinal cord extracts from an ALS patient induced the formation of TDP-43 pathology that progressively spread in a time-dependent manner in cerebral organoids, suggesting that pathogenic TDP-43 from ALS functioned as seeds and propagated cell-to-cell to form de novo TDP-43 pathology. We also reported that the administration of ALS patient-derived protein extracts caused astrocyte proliferation to form astrogliosis in cerebral organoids, reproducing the pathological feature seen in ALS. Moreover, we showed pathogenic TDP-43 induced cellular apoptosis and that TDP-43 pathology correlated with genomic damage due to DNA double-strand breaks. Thus, our results provide evidence that patient-derived pathogenic TDP-43 can mimic the prion-like propagation of TDP-43 pathology in human CNS tissue. Our findings indicate that our assays with human cerebral organoids that replicate ALS pathophysiology have a promising strategy for creating readouts that could be used in future drug discovery efforts against ALS.

Molecular Dissection of TDP-43 as a Leading Cause of ALS/FTLD.

TAR DNA binding protein 43 (TDP-43) is a DNA/RNA binding protein involved in pivotal cellular functions, especially in RNA metabolism. Hyperphosphorylated and ubiquitinated TDP-43-positive neuronal cytoplasmic inclusions are identified in the brain and spinal cord in most cases of amyotrophic lateral sclerosis (ALS) and a substantial proportion of frontotemporal lobar degeneration (FTLD) cases. TDP-43 dysfunctions and cytoplasmic aggregation seem to be the central pathogenicity in ALS and FTLD. Therefore, unraveling both the physiological and pathological mechanisms of TDP-43 may enable the exploration of novel therapeutic strategies. This review highlights the current understanding of TDP-43 biology and pathology, describing the cellular processes involved in the pathogeneses of ALS and FTLD, such as post-translational modifications, RNA metabolism, liquid-liquid phase separation, proteolysis, and the potential prion-like propagation propensity of the TDP-43 inclusions.

[Immunotherapy Against Misfolded Proteins in ALS].

Protein misfolding crucially underlies the pathogenesis of amyotrophic lateral sclerosis (ALS). Mutant superoxide dismutase 1 (SOD1) and TAR DNA-binding protein 43kDa (TDP-43) are major causal proteins for familial and sporadic ALS, respectively, provoking diverse pathogenic pathways in both intracellular and extracellular environments. Of note, cell-to-cell spreading behavior is implicated in the progression of neurodegeneration, suggesting application in immunotherapies including vaccination, and antibody application as a molecular targeting therapy, due to strict antigen-specificity. Although immunotherapy of intravenous application of full-length immunoglobulin is aimed at targeting the extracellular proteins because of low access to the cytosol, it is therefore necessary to generate expression vectors for variable single chain fragments (scFv) that target intracellular proteins. Despite the advantages of scFv, such as low molecular size and the ability to apply molecular modifications adding proteolytic signals, safety and efficacy should be cautiously estimated in preclinical studies, using appropriate animal models. In ALS, we firstly succeeded in the vaccination of mutant SOD1 transgenic mice, which was followed by accumulating evidence showing the efficacy of immunization against misfolded SOD1. In TDP-43 proteinopathy, we are developing immunotherapy using intrabodies with proteolytic properties against mislocalized or aggregated forms of TDP-43 inside cells.

Elimination of TDP-43 inclusions linked to amyotrophic lateral sclerosis by a misfolding-specific intrabody with dual proteolytic signals.

Aggregation of TAR DNA-binding protein of 43 kDa (TDP-43) is implicated in the pathogenesis of sporadic and certain familial forms of amyotrophic lateral sclerosis (ALS), suggesting elimination of TDP-43 aggregates as a possible therapeutic strategy. Here we generated and investigated a single-chain variable fragment (scFv) derived from the 3B12A monoclonal antibody (MAb) that recognises D247 of the TDP-43 nuclear export signal, an epitope masked in the physiological state. In transfected HEK293A cells, 3B12A scFv recapitulated the affinity of the full-length MAb to mislocalised TDP-43 with a defective nuclear localising signal and to a TDP-43 inclusion mimic with cysteine-to-serine substitution at RRM1. Moreover, 3B12A scFv accelerated proteasome-mediated degradation of aggregated TDP-43, likely due to an endogenous PEST-like proteolytic signal sequence in the VH domain CDR2 region. Addition of the chaperone-mediated autophagy (CMA)-related signal to 3B12A scFv induced HSP70 transcription, further enhancing TDP-43 aggregate clearance and cell viability. The 3B12A scFv also reduced TDP-43 aggregates in embryonic mouse brain following in utero electroporation while causing no overt postnatal brain pathology or developmental anomalies. These results suggest that a misfolding-specific intrabody prone to synergistic proteolysis by proteasomal and autophagic pathways is a promising strategy for mitigation of TDP-43 proteinopathy in ALS.

CUL2-mediated clearance of misfolded TDP-43 is paradoxically affected by VHL in oligodendrocytes in ALS.

The molecular machinery responsible for cytosolic accumulation of misfolded TDP-43 in amyotrophic lateral sclerosis (ALS) remains elusive. Here we identified a cullin-2 (CUL2) RING complex as a novel ubiquitin ligase for fragmented forms of TDP-43. The von Hippel Lindau protein (VHL), a substrate binding component of the complex, preferentially recognized misfolded TDP-43 at Glu246 in RNA-recognition motif 2. Recombinant full-length TDP-43 was structurally fragile and readily cleaved, suggesting that misfolded TDP-43 is cleared by VHL/CUL2 in a step-wise manner via fragmentation. Surprisingly, excess VHL stabilized and led to inclusion formation of TDP-43, as well as mutant SOD1, at the juxtanuclear protein quality control center. Moreover, TDP-43 knockdown elevated VHL expression in cultured cells, implying an aberrant interaction between VHL and mislocalized TDP-43 in ALS. Finally, cytoplasmic inclusions especially in oligodendrocytes in ALS spinal cords were immunoreactive to both phosphorylated TDP-43 and VHL. Thus, our results suggest that an imbalance in VHL and CUL2 may underlie oligodendrocyte dysfunction in ALS, and highlight CUL2 E3 ligase emerges as a novel therapeutic potential for ALS.

Microscopic polyangiitis complicated with ileal involvement detected by double-balloon endoscopy: a case report.

BACKGROUND: Microscopic polyangiitis is characterized by pauci-immune, necrotizing small-vessel vasculitis and an anti-neutrophil cytoplasmic antibody-associated vasculitis. Although gastrointestinal involvement in microscopic polyangiitis is not rare, endoscopic observation of it is extremely rare. To the best of our knowledge, this is the first case report of small intestinal involvement in microscopic polyangiitis detected and followed up by double-balloon endoscopy. CASE PRESENTATION: A 70-year-old Japanese woman was transferred to our hospital for close examination of suspected small intestinal lymphoma. Retrograde double-balloon endoscopy revealed various forms of ulcers with redness and edema in the ileum. Histological findings suggested ischemic changes. Because mononeuritis multiplex and a fever spike appeared later, vasculitis was suspected. The perinuclear anti-neutrophil cytoplasmic antibody titer was elevated. Nerve biopsy results suggested vasculitis. From these findings, microscopic polyangiitis was diagnosed. It was suggested that microscopic polyangiitis caused the intestinal involvement. Intravenous pulse cyclophosphamide and oral predonisolone were started. After treatment, perinuclear anti-neutrophil cytoplasmic antibodies decreased to the normal range. Retrograde double-balloon endoscopy after treatment showed ulcer scars and no ulcer. CONCLUSION: The cause of gastrointestinal involvement in microscopic polyangiitis is ischemia due to vasculitis. It is difficult to diagnose small-vessel vasculitis by endoscopic biopsy. Although histological evidence of microscopic polyangiitis is important, the treatment should not be delayed by repeating the biopsy, because such delay can result in adverse sequela.This case report shows that microscopic polyangiitis should be considered as a differential diagnosis when small intestinal changes like those in the present case are observed by endoscopy.