Elevated cholesterol in ATAD3 mutants is a compensatory mechanism that leads to membrane cholesterol aggregation.

Aberrant cholesterol metabolism causes neurological disease and neurodegeneration, and mitochondria have been linked to perturbed cholesterol homeostasis via the study of pathological mutations in the ATAD3 gene cluster. However, whether the cholesterol changes were compensatory or contributory to the disorder was unclear, and the effects on cell membranes and the wider cell were also unknown. Using patient-derived cells, we show that cholesterol perturbation is a conserved feature of pathological ATAD3 variants that is accompanied by an expanded lysosome population containing membrane whorls characteristic of lysosomal storage diseases.

CRISPR/Cas9-mediated tissue-specific knockout and cDNA rescue using sgRNAs that target exon-intron junctions in .

In this protocol, we take CRISPR/Cas9 and Gal4/UAS approaches to achieve tissue-specific knockout in parallel with rescue of the knockout by cDNA expression in . We demonstrate that guide RNAs targeting the exon-intron junction of target genes cleave the genomic locus of the genes, but not transgenes, in a tissue where Gal4 drives Cas9 expression. The efficiency of this approach enables the determination of pathogenicity of disease-associated variants in human genes in a tissue-specific manner in .

Bi-allelic variants in OGDHL cause a neurodevelopmental spectrum disease featuring epilepsy, hearing loss, visual impairment, and ataxia.

The 2-oxoglutarate dehydrogenase-like (OGDHL) protein is a rate-limiting enzyme in the Krebs cycle that plays a pivotal role in mitochondrial metabolism. OGDHL expression is restricted mainly to the brain in humans. Here, we report nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Functional interpretation of ATAD3A variants in neuro-mitochondrial phenotypes.

Background: ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane-anchored protein involved in diverse processes including mitochondrial dynamics, mitochondrial DNA organization, and cholesterol metabolism. Biallelic deletions (null), recessive missense variants (hypomorph), and heterozygous missense variants or duplications (antimorph) in ATAD3A lead to neurological syndromes in humans.

Methods: To expand the mutational spectrum of ATAD3A variants and to provide functional interpretation of missense alleles in trans to deletion alleles, we performed exome sequencing for identification of single nucleotide variants (SNVs) and copy number variants (CNVs) in ATAD3A in individuals with neurological and mitochondrial phenotypes.

Knockdown of genes involved in axonal transport enhances the toxicity of human neuromuscular disease-linked MATR3 mutations in Drosophila.

Mutations in the nuclear matrix protein Matrin 3 (MATR3) have been identified in amyotrophic lateral sclerosis and myopathy. To investigate the mechanisms underlying MATR3 mutations in neuromuscular diseases and efficiently screen for modifiers of MATR3 toxicity, we generated transgenic MATR3 flies. Our findings indicate that expression of wild-type or mutant MATR3 in motor neurons reduces climbing ability and lifespan of flies, while their expression in indirect flight muscles (IFM) results in abnormal wing positioning and muscle degeneration.

A biallelic pathogenic variant in the OGDH gene results in a neurological disorder with features of a mitochondrial disease.

2-Oxoglutarate dehydrogenase (OGDH) is a rate-limiting enzyme in the mitochondrial TCA cycle, encoded by the OGDH gene. α-Ketoglutarate dehydrogenase (OGDH) deficiency was previously reported in association with developmental delay, hypotonia, and movement disorders and metabolic decompensation, with no genetic data provided. Using whole exome sequencing, we identified two individuals carrying a homozygous missense variant c.

Recurrent De Novo NAHR Reciprocal Duplications in the ATAD3 Gene Cluster Cause a Neurogenetic Trait with Perturbed Cholesterol and Mitochondrial Metabolism.

Recent studies have identified both recessive and dominant forms of mitochondrial disease that result from ATAD3A variants. The recessive form includes subjects with biallelic deletions mediated by non-allelic homologous recombination. We report five unrelated neonates with a lethal metabolic disorder characterized by cardiomyopathy, corneal opacities, encephalopathy, hypotonia, and seizures in whom a monoallelic reciprocal duplication at the ATAD3 locus was identified.

Biallelic Mutations in ATP5F1D, which Encodes a Subunit of ATP Synthase, Cause a Metabolic Disorder.

ATP synthase, H transporting, mitochondrial F1 complex, δ subunit (ATP5F1D; formerly ATP5D) is a subunit of mitochondrial ATP synthase and plays an important role in coupling proton translocation and ATP production. Here, we describe two individuals, each with homozygous missense variants in ATP5F1D, who presented with episodic lethargy, metabolic acidosis, 3-methylglutaconic aciduria, and hyperammonemia. Subject 1, homozygous for c.

Neuronal overexpression of human VAPB slows motor impairment and neuromuscular denervation in a mouse model of ALS.

Four mutations in the VAMP/synaptobrevin-associated protein B (VAPB) gene have been linked to amyotrophic lateral sclerosis (ALS) type 8. The mechanism by which VAPB mutations cause motor neuron disease is unclear, but studies of the most common P56S variant suggest both loss of function and dominant-negative sequestration of wild-type protein. Diminished levels of VAPB and its proteolytic cleavage fragment have also been reported in sporadic ALS cases, suggesting that VAPB loss of function may be a common mechanism of disease.

Loss of Nardilysin, a Mitochondrial Co-chaperone for α-Ketoglutarate Dehydrogenase, Promotes mTORC1 Activation and Neurodegeneration.

We previously identified mutations in Nardilysin (dNrd1) in a forward genetic screen designed to isolate genes whose loss causes neurodegeneration in Drosophila photoreceptor neurons. Here we show that NRD1 is localized to mitochondria, where it recruits mitochondrial chaperones and assists in the folding of α-ketoglutarate dehydrogenase (OGDH), a rate-limiting enzyme in the Krebs cycle. Loss of Nrd1 or Ogdh leads to an increase in α-ketoglutarate, a substrate for OGDH, which in turn leads to mTORC1 activation and a subsequent reduction in autophagy.

Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes.

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.

A TRPV channel in Drosophila motor neurons regulates presynaptic resting Ca2+ levels, synapse growth, and synaptic transmission.

Presynaptic resting Ca(2+) influences synaptic vesicle (SV) release probability. Here, we report that a TRPV channel, Inactive (Iav), maintains presynaptic resting [Ca(2+)] by promoting Ca(2+) release from the endoplasmic reticulum in Drosophila motor neurons, and is required for both synapse development and neurotransmission. We find that Iav activates the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin, which is essential for presynaptic microtubule stabilization at the neuromuscular junction.

A mitocentric view of Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disease, yet the underlying causative molecular mechanisms are ill defined. Numerous observations based on drug studies and mutations in genes that cause PD point to a complex set of rather subtle mitochondrial defects that may be causative. Indeed, intensive investigation of these genes in model organisms has revealed roles in the electron transport chain, mitochondrial protein homeostasis, mitophagy, and the fusion and fission of mitochondria.

Apicularen A acetate induces cell death via AIF translocation and disrupts the microtubule network by down-regulating tubulin in HM7 human colon cancer cells.

Apicularen A is a novel antitumor agent and strongly induces death in tumor cells. In this study, we synthesized apicularen A acetate, an acetyl derivative of apicularen A, and investigated its antitumor effect and mechanism in HM7 colon cancer cells. Apicularen A acetate induced apoptotic cell death and caspase-3 activation; however, the pan-caspase inhibitor Z-VAD-fmk could not prevent this cell death.

Group choreography: mechanisms orchestrating the collective movement of border cells.

Cell movements are essential for animal development and homeostasis but also contribute to disease. Moving cells typically extend protrusions towards a chemoattractant, adhere to the substrate, contract and detach at the rear. It is less clear how cells that migrate in interconnected groups in vivo coordinate their behaviour and navigate through natural environments.

Omega-3-polyunsaturated fatty acids suppress pancreatic cancer cell growth in vitro and in vivo via downregulation of Wnt/Beta-catenin signaling.

Background/aims: ω3-polyunsaturated fatty acids (ω3- PUFAs) are known to possess anticancer properties. However, the relationship between ω3-PUFAs and β-catenin, one of the key components of the Wnt signaling pathway, in human pancreatic cancer remains poorly characterized.

Methods: Human pancreatic cancer cells (SW1990 and PANC-1) were exposed to two ω3-PUFAs, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), to investigate the relationship between ω3-PUFAs and the Wnt/β-catenin signaling pathway in vitro.

miRNA-mediated feedback inhibition of JAK/STAT morphogen signalling establishes a cell fate threshold.

Patterns of cell fates generated by morphogens are critically important for normal development; however, the mechanisms by which graded morphogen signals are converted into all-or-none cell fate responses are incompletely understood. In the Drosophila ovary, high and sustained levels of the secreted morphogen Unpaired (Upd) specify the migratory border-cell population by activating the signal transducer and activator of transcription (STAT). A lower or transient level of STAT activity specifies a non-migratory population of follicle cells.

Protein-bound polysaccharide from Phellinus linteus inhibits tumor growth, invasion, and angiogenesis and alters Wnt/β-catenin in SW480 human colon cancer cells.

Background: Polysaccharides extracted from the Phellinus linteus (PL) mushroom are known to possess anti-tumor effects. However, the molecular mechanisms responsible for the anti-tumor properties of PL remain to be explored. Experiments were carried out to unravel the anticancer effects of PL.

Identification of Novel Phosphorylation Motifs Through an Integrative Computational and Experimental Analysis of the Human Phosphoproteome.

Protein phosphorylation occurs in certain sequence/structural contexts that are still incompletely understood. The amino acids surrounding the phosphorylated residues are important in determining the binding of the kinase to the protein sequence. Upon phosphorylation these sequences also determine the binding of certain domains that specifically bind to phosphorylated sequences.

A serum-stable branched dimeric anti-VEGF peptide blocks tumor growth via anti-angiogenic activity.

Angiogenesis is critical and indispensable for tumor progression. Since VEGF is known to play a central role in angiogenesis, the disruption of VEGF-VEGF receptor system is a promising target for anti-cancer therapy. Previously, we reported that a hexapeptide (RRKRRR, RK6) blocked the growth and metastasis of tumor by inhibiting VEGF binding to its receptors.

Overexpression of hepatocyte nuclear factor-3alpha induces apoptosis through the upregulation and accumulation of cytoplasmic p53 in prostate cancer cells.

Background: Hepatocyte nuclear factor-3alpha (HNF-3alpha) has been known to act as a repressor in the pathogenesis of many cancers. Herein, we investigated the effect of HNF-3alpha overexpression in prostate cancer cells.

Methods: HNF-3alpha was overexpressed in prostate cancer cells using an adenovirus recombinant expressing wild-type HNF-3alpha.