Involvement of mTOR pathway in neurodegeneration in NSF-related developmental and epileptic encephalopathy.

Membrane fusion is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. During neurotransmitter exocytosis, SNARE proteins on a synaptic vesicle and the target membrane form a complex, resulting in neurotransmitter release. N-ethylmaleimide-sensitive factor (NSF), a homohexameric ATPase, disassembles the complex, allowing individual SNARE proteins to be recycled. Recently, the association between pathogenic NSF variants and developmental and epileptic encephalopathy (DEE) was reported; however, the molecular pathomechanism of NSF-related DEE remains unclear. Here, three patients with de novo heterozygous NSF variants were presented, of which two were associated with DEE and one with a very mild phenotype. One of the DEE patients also had hypocalcemia from parathyroid hormone deficiency and neuromuscular junction impairment. Using PC12 cells, a neurosecretion model, we show that NSF with DEE-associated variants impaired the recycling of vesicular membrane proteins and vesicle enlargement in response to exocytotic stimulation. In addition, DEE-associated variants caused neurodegenerative change and defective autophagy through overactivation of the mammalian/mechanistic target of rapamycin (mTOR) pathway. Treatment with rapamycin, an mTOR inhibitor or overexpression of wild-type NSF ameliorated these phenotypes. Furthermore, neurons differentiated from patient-derived induced pluripotent stem cells showed neurite degeneration, which was also alleviated by rapamycin treatment or gene correction using genome editing. Protein structure analysis of NSF revealed that DEE-associated variants might disrupt the transmission of the conformational change of NSF monomers and consequently halt the rotation of ATP hydrolysis, indicating a dominant negative mechanism. In conclusion, this study elucidates the pathomechanism underlying NSF-related DEE and identifies a potential therapeutic approach.

Long-read sequencing identifies an SVA_D retrotransposon insertion deep within the intron of ATP7A as a novel cause of occipital horn syndrome.

BACKGROUND: SINE-VNTR-Alu (SVA) retrotransposons move from one genomic location to another in a 'copy-and-paste' manner. They continue to move actively and cause monogenic diseases through various mechanisms. Currently, disease-causing SVA retrotransposons are classified into human-specific young SVA_E or SVA_F subfamilies. In this study, we identified an evolutionarily old SVA_D retrotransposon as a novel cause of occipital horn syndrome (OHS). OHS is an X-linked, copper metabolism disorder caused by dysfunction of the copper transporter, ATP7A. METHODS: We investigated a 16-year-old boy with OHS whose pathogenic variant could not be detected via routine molecular genetic analyses. RESULTS: A 2.8 kb insertion was detected deep within the intron of the patient's ATP7A gene. This insertion caused aberrant mRNA splicing activated by a new donor splice site located within it. Long-read circular consensus sequencing enabled us to accurately read the entire insertion sequence, which contained highly repetitive and GC-rich segments. Consequently, the insertion was identified as an SVA_D retrotransposon. Antisense oligonucleotides (AOs) targeting the new splice site restored the expression of normal transcripts and functional ATP7A proteins. AO treatment alleviated excessive accumulation of copper in patient fibroblasts in a dose-dependent manner. Pedigree analysis revealed that the retrotransposon had moved into the OHS-causing position two generations ago. CONCLUSION: This is the first report of a human monogenic disease caused by the SVA_D retrotransposon. The fact that the evolutionarily old SVA_D is still actively transposed, leading to increased copy numbers may make a notable impact on rare genetic disease research.

A 37-Year-Old Man With Intellectual Disability Discovered to Have Aspartylglucosaminuria: Implications for the Diagnosis of Genetic Causes.

Objectives: The causes of intellectual disability (ID) are varied, with as many as 1,400 causative genes. We attempted to identify the causative gene in a patient with long-standing undiagnosed ID. Methods: Although this was an isolated case with no family history, we searched for the causative gene using trio-based whole-exome sequencing (trio-WES), because severe ID is often caused by genetic variations, and inherited metabolic disorders (IMDs) are assumed to be the cause when regression and epilepsy occur. Results: We identified homozygous donor splice-site variants in the AGA gene (aspartylglucosaminidase; NM_000027.4) Chr4(GRCh38):g. 177436275C>A, c.698+1G>T. This gene is implicated in aspartylglucosaminuria (AGU; OMIM #208400) and originated from both of the patient's parents. We confirmed the pathogenicity of the variant by detecting the splicing defect in cDNA from the patient's blood and accumulation of aberrant metabolites in the patient's urine. Discussion: We discuss how to more readily achieve an accurate diagnosis for patients with undiagnosed intellectual disabilities. Medical practitioners' awareness of the characteristics of the disease leading to clinical suspicion in patients with matching presentations, and the performance of newborn screening when possible, is important for the diagnosis of ID. In addition, the characteristic symptoms and course of the disease give rise to suspicion of IMDs. Given our results, we consider trio-WES to be a powerful method for identifying the causative genes in cases of ID with genetic causes.

Identification of Novel Series of Potent and Selective Relaxin Family Peptide Receptor 1 (RXFP1) Agonists.

Relaxin H2 is a clinically relevant peptide agonist for relaxin family peptide receptor 1 (RXFP1), but a combination of this hormone's short plasma half-life and the need for injectable delivery limits its therapeutic potential. We sought to overcome these limitations through the development of a potent small molecule (SM) RXFP1 agonist. Although two large SM HTS campaigns failed in identifying suitable hit series, we uncovered novel chemical space starting from the only known SM RXFP1 agonist series, represented by ML290. Following a design-make-test-analyze strategy based on improving early dose to man ranking, we discovered compound 42 (AZ7976), a highly selective RXFP1 agonist with sub-nanomolar potency. We used AZ7976, its 10 000-fold less potent enantiomer 43 and recombinant relaxin H2 to evaluate in vivo pharmacology and demonstrate that AZ7976-mediated heart rate increase in rats was a result of RXFP1 agonism. As a result, AZ7976 was selected as lead for continued optimization.

[Data-driven drug discovery for drug repurposing].

To improve the decreased efficiency of drug discovery and development, drug repurposing (also called drug repositioning) has been expected, that it is a strategy for identifying new medical indications for approved, investigational or suspended drugs. Particularly, according to the rapid expansion of medical and life science data and the remarkable technological progress of AI technology in recent years, the approach of computational drug repurposing has been attracted as one of the applications in data-driven drug discovery. Computational drug repurposing is a method of systematical and strategical research for identifying novel indication candidates and prioritizing the indication candidates based on the various profiles of drugs, genes, and diseases. In this review article, the typical data science techniques for data-driven drug repurposing, 1. drug-target interaction prediction, 2. transcriptomics-based approach by using differentially gene expression profiles, 3. natural language processing and word embedding, and their current status were summarized. We have also introduced a use case of data-driven drug repurposing for the PPARγ/α agonist Netoglitazone that we actually analyzed. In addition, as an excellent successful case of data-driven drug repurposing in recent years, we have also discussed a repurposing case reported by BenevolentAI in 2020, that Baricitinib has been identified as a potential intervention for COVID-19, based on immunomodulatory treatment by its mechanism of action as a JAK1 and JAK2 inhibition.

Leigh-like syndrome with progressive cerebellar atrophy caused by novel HIBCH variants.

Pathogenic variants in the HIBCH gene cause HIBCH deficiency, leading to mitochondrial disorders associated with valine metabolism. Patients typically present with symptoms such as developmental regression/delay, encephalopathy, hypotonia and dystonia. Brain magnetic resonance imaging (MRI) shows bilateral lesions in the basal ganglia with/without brainstem involvement. Here, we report a case of a Japanese patient with Leigh-like syndrome caused by novel HIBCH variants. Long-term follow-up MRI revealed progressive cerebellar atrophy, which expands the phenotypic spectrum of HIBCH deficiency.

Isolated sixth nerve palsy as an initial presentation of primary angiitis of the central nervous system.

BACKGROUND: Primary angiitis of the central nervous system (PACNS) is a newly-emerging disease, and it is known that early diagnosis with treatment is important for the improvement of prognosis. CASE DESCRIPTION: Here, we report the case of a previously healthy 13-year-old girl who presented with right eye abduction failure, attributed to isolated right sixth nerve palsy, as the initial symptom of PACNS. Magnetic resonance angiography (MRA) showed stenosis in the distal portion of the right internal carotid artery, and delay alternating with nutation for tailored excitation (DANTE)-prepared contrast-enhanced magnetic resonance imaging confirmed vasculitis at the same site. The patient was subsequently treated with three courses of pulse corticosteroid therapy (methylprednisolone intravenously 30 mg/kg/day for three consecutive days). Diplopia completely resolved within 3 months after three course of steroid pulse therapy, and when taking 10 mg PSL daily. Follow-up MRA confirmed complete resolution of the arterial narrowing, and no relapse was observed after 2 months of steroid cessation. DISCUSSION: This case report illustrates an unusual presentation of PACNS with isolated sixth nerve palsy. PACNS was thought to cause insults on a single cranial nerve either through local spread of inflammation or hypoxic-ischemic insults on the nerve root due to involvement of feeding microvessels. The decision to perform imaging studies in cases of isolated sixth nerve palsy remains controversial because of the possibility of spontaneous recovery. Our case supports the existing literature that recommends that even an isolated symptom of unilateral abducens nerve palsy requires timely imaging studies.

MOV10 as a novel telomerase-associated protein.

A novel telomerase-associated protein was isolated from porcine testis. The 115-kDa protein, purified with telomerase activity, was molecular cloned using human cDNA library, and identified as MOV10. The expression levels of both MOV10 mRNA and MOV10 protein in cancer cells were 2-3 times higher than that of the normal cells, and MOV10 mRNA was highly expressed in human testis and ovary. The anti-MOV10 antibody precipitated the telomerase activity from cancer cell extracts, and inhibited the telomerase activity in vitro. Sf9-expressed MOV10 protein bound to G-rich strand of both single- and double-stranded telomere-sequenced DNA, but not to single C-rich strand. ChIP assay showed the binding of MOV10 to telomere region in vivo. These data suggest that MOV10 is involved in the progression of telomerase-catalyzing reaction via the interaction of telomerase protein and telomere DNA.