UNASSIGNED: Osteosarcoma (OS) is highly malignant and prone to local infiltration and distant metastasis. Due to the poor outcomes of OS patients, the study aimed to identify differentially expressed genes (DEGs) in OS and explore their role in the carcinogenesis and progression of OS.
UNASSIGNED: RNA sequencing was performed to identify DEGs in OS. The functions of the DEGs in OS were investigated using bioinformatics analysis, and DEG expression was verified using RT-qPCR and Western blotting. The role of SLC25A4 was evaluated using gene set enrichment analysis (GSEA) and then investigated using functional assays in OS cells.
UNASSIGNED: In all, 8353 DEGs were screened. GO and KEGG enrichment analyses indicated these DEGs showed strong enrichment in the calcium signaling pathway and pathways in cancer. Moreover, the Kaplan-Meier survival analysis showed ten hub genes were related to the outcomes of OS patients. Both SLC25A4 transcript and protein expression were significantly reduced in OS, and GSEA suggested that SLC25A4 was associated with cell cycle, apoptosis and inflammation. SLC25A4-overexpressing OS cells exhibited suppressed proliferation, migration, invasion and enhanced apoptosis.
UNASSIGNED: SLC25A4 was found to be significantly downregulated in OS patients, which was associated with poor prognosis. Modulation of SLC25A4 expression levels may be beneficial in OS treatment.

Swine influenza virus (SIV) not only brings about great economic losses on the global pig industry, it also poses a significant threat to the public health for its interspecies transmission capacity. Porcine β-defensin 2 (PBD-2) is a host defense peptide and our previous study has shown that PBD-2 inhibits proliferation of enveloped pseudorabies virus both in vitro and in transgenic (TG) mice. The aim of this study is to investigate the possible anti-SIV ability of PBD-2 in a TG pig model created in our previous study. The in-contact challenge trial demonstrated that overexpression of PBD-2 in pigs could efficiently alleviate SIV-associated clinical signs. The SIV titers quantified by EID50 in lung tissues of infected TG pigs were significantly lower than that of wild-type littermates. In vitro, the cell viability assay revealed that PBD-2 mainly interfered with viral entry and post-infection stages. It was further confirmed that PBD-2 could enter porcine tracheal epithelial cells. The proteins interacting with PBD-2 inside host cells were identified with immunoprecipitation and the pathways involved were analyzed. Results showed that PBD-2 could interact with pro-apoptotic solute carrier family 25 member 4 (SLC25A4), also known as adenine nucleotide translocase 1, and thereby inhibited SIV-induced cell apoptosis. The molecular docking analysis suggested that PBD-2 interacted with porcine SLC25A4 mainly through strong hydrogen binding, with the predicted binding affinity being -13.23 kcal/mol. Altogether, these indicate that PBD-2 protects pigs against SIV infection, which may result from its role as a SLC25A4 blocker to alleviate cell apoptosis, providing a novel therapeutic and prophylactic strategy of using PBD-2 to combat SIV.

RBFOX2, which has a well-established role in alternative splicing, is linked to heart diseases. However, it is unclear whether RBFOX2 has other roles in RNA processing that can influence gene expression in muscle cells, contributing to heart disease. Here, we employ both 3\'-end and nanopore cDNA sequencing to reveal a previously unrecognized role for RBFOX2 in maintaining alternative polyadenylation (APA) signatures in myoblasts. RBFOX2-mediated APA modulates mRNA levels and/or isoform expression of a collection of genes, including contractile and mitochondrial genes. Depletion of RBFOX2 adversely affects mitochondrial health in myoblasts, correlating with disrupted APA of mitochondrial gene Slc25a4. Mechanistically, RBFOX2 regulation of Slc25a4 APA is mediated through consensus RBFOX2 binding motifs near the distal polyadenylation site, enforcing the use of the proximal polyadenylation site. In sum, our results unveil a role for RBFOX2 in fine-tuning expression of mitochondrial and contractile genes via APA in myoblasts relevant to heart diseases.

BACKGROUND: Autosomal dominant mitochondrial DNA depletion syndrome (MTDPS-12A) is characterized by severe hypotonia from birth due to a mutation in the adenine nucleotide translocator 1 (ANT1).
METHODS: A 4-year-old female patient diagnosed with neonatal-onset mitochondrial disease, who had good cognitive function while receiving antiepileptic treatment, presented with sudden-onset status epilepticus with facial and limb myoclonus persisting for more than 30 min. Subsequently, she developed epileptic encephalopathy. Brain MRI showed progressive ventricular enlargement and marked white matter atrophy. She was unable to perform verbal communication or make eye contact and fingertip movements. She lacked any signs of cardiomyopathy. Sanger sequencing demonstrated a heterozygous de novo mutation of c.239G>A (p.Arg80His) in SLC25A4. Her right quadriceps muscle tissue showed lowered complexes I, III, and IV activities and mitochondria DNA depletion (mitochondria/nuclear DNA: 14.6 ± 2.2%) through the quantitative polymerase chain reaction. She was definitively diagnosed with MTDPS-12A.
CONCLUSIONS: Status epilepticus causes encephalopathy in patients with MTDPS-12A. Reducing the energy requirement on the cardiac muscle and brain may be a treatment strategy for patients with MTDPS-12A. Therefore, seizure management and preventive treatment of status epilepticus are considered to be important for maintaining neurodevelopmental outcomes.

Airway hydration and ciliary function are critical to airway homeostasis and dysregulated in chronic obstructive pulmonary disease (COPD), which is impacted by cigarette smoking and has no therapeutic options. We utilized a high-copy cDNA library genetic selection approach in the amoeba Dictyostelium discoideum to identify genetic protectors to cigarette smoke. Members of the mitochondrial ADP/ATP transporter family adenine nucleotide translocase (ANT) are protective against cigarette smoke in Dictyostelium and human bronchial epithelial cells. Gene expression of ANT2 is reduced in lung tissue from COPD patients and in a mouse smoking model, and overexpression of ANT1 and ANT2 resulted in enhanced oxidative respiration and ATP flux. In addition to the presence of ANT proteins in the mitochondria, they reside at the plasma membrane in airway epithelial cells and regulate airway homeostasis. ANT2 overexpression stimulates airway surface hydration by ATP and maintains ciliary beating after exposure to cigarette smoke, both of which are key functions of the airway. Our study highlights a potential for upregulation of ANT proteins and/or of their agonists in the protection from dysfunctional mitochondrial metabolism, airway hydration and ciliary motility in COPD.This article has an associated First Person interview with the first author of the paper.

Neurodevelopmental disorders offer insight into synaptic mechanisms. To unbiasedly uncover these mechanisms, we studied the 22q11.2 syndrome, a recurrent copy number variant, which is the highest schizophrenia genetic risk factor. We quantified the proteomes of 22q11.2 mutant human fibroblasts from both sexes and mouse brains carrying a 22q11.2-like defect, Df(16)A+/- Molecular ontologies defined mitochondrial compartments and pathways as some of top ranked categories. In particular, we identified perturbations in the SLC25A1-SLC25A4 mitochondrial transporter interactome as associated with the 22q11.2 genetic defect. Expression of SLC25A1-SLC25A4 interactome components was affected in neuronal cells from schizophrenia patients. Furthermore, hemideficiency of the Drosophila SLC25A1 or SLC25A4 orthologues, dSLC25A1-sea and dSLC25A4-sesB, affected synapse morphology, neurotransmission, plasticity, and sleep patterns. Our findings indicate that synapses are sensitive to partial loss of function of mitochondrial solute transporters. We propose that mitoproteomes regulate synapse development and function in normal and pathological conditions in a cell-specific manner.SIGNIFICANCE STATEMENT We address the central question of how to comprehensively define molecular mechanisms of the most prevalent and penetrant microdeletion associated with neurodevelopmental disorders, the 22q11.2 microdeletion syndrome. This complex mutation reduces gene dosage of ∼63 genes in humans. We describe a disruption of the mitoproteome in 22q11.2 patients and brains of a 22q11.2 mouse model. In particular, we identify a network of inner mitochondrial membrane transporters as a hub required for synapse function. Our findings suggest that mitochondrial composition and function modulate the risk of neurodevelopmental disorders, such as schizophrenia.

There is no comprehensive overview concerning the phenotypic variability in patients carrying SLC25A4 mutations available. Therefore, the aim of the present review was to summarise and discuss recent findings concerning the clinical presentation and phenotypic heterogeneity of SLC25A4 mutations. The study was conducted by systematically reviewing the literature using the search terms \'mitochondrial\', \"myopathy\', \'nuclear DNA\', \'mitochondrial DNA\', in combination with \'SLC25A4\' or \'AAC1\'. The results indicated that the phenotypic heterogeneity in patients carrying a SLC25A4 mutation is broader than so far anticipated. Patients carrying a SLC25A4 mutation not only manifest as encephalo-myo-cardiomyopathy but also with scoliosis, cataract, depression, headache, hydrocephalus or arterial hypertension. SLC25A4 mutations may result in mtDNA depletion or multiple mitochondrial (mt)DNA deletions. SLC25A4-associated mtDNA depletion presents with the more severe phenotype and the worse outcome than patients with multiple mtDNA deletions. Depletion syndrome due to SLC25A4 mutations is associated with congenital respiratory insufficiency requiring mechanical ventilation with poor prognosis in the majority of the cases. Mutations in the SLC25A4 gene manifest phenotypically with multiorgan abnormalities in addition to encephalo-myo-cardiomyopathy. SLC25A4 mutations, causing mtDNA depletion, present with a more severe phenotype, including respiratory insufficiency and more widespread cerebral disease than mutations causing multiple mtDNA deletions.

The mitochondrial ADP/ATP carrier is a nuclear encoded protein, which catalyzes the exchange of ATP generated in mitochondria with ADP produced in the cytosol. In humans, mutations in the major ADP/ATP carrier gene, ANT1, are involved in several degenerative mitochondrial pathologies, leading to instability of mitochondrial DNA. Recessive mutations have been associated with mitochondrial myopathy and cardiomyopathy whereas dominant mutations have been associated with autosomal dominant Progressive External Ophtalmoplegia (adPEO). Recently, two de novo dominant mutations, R80H and R235G, leading to extremely severe symptoms, have been identified. In order to evaluate if the dominance is due to haploinsufficiency or to a gain of function, the two mutations have been introduced in the equivalent positions of the AAC2 gene, the yeast orthologue of human ANT1, and their dominant effect has been studied in heteroallelic strains, containing both one copy of wild type AAC2 and one copy of mutant aac2 allele. Through phenotypic characterization of these yeast models we showed that the OXPHOS phenotypes in the heteroallelic strains were more affected than in the hemiallelic strain indicating that the dominant trait of the two mutations is due to gain of function.

We report the clinical, morphological and molecular features of two patients with autosomal recessive SLC25A4 (ANT1) gene mutations. Furthermore, all previously published cases are reviewed to identify valuable features for future diagnosis. Patients present a common phenotype with exercise intolerance, hyperlactatemia, and hypertrophic cardiomyopathy. Muscle biopsies show wide sub-sarcolemmal mitochondrial aggregates, and increased activities of all respiratory chain complexes. The phenotype of recessive SLC25A4 (ANT1) mutations although rare, is homogenous and easily recognizable and could help orientate the molecular analysis in adults with exercise intolerance associated with hyperlactatemia.

OBJECTIVE: TSPO is a neuroinflammatory biomarker and emerging therapeutic target in psychiatric disorders. We evaluated whether TSPO polymorphisms contribute to interindividual variability in schizophrenia, antipsychotic efficacy and antipsychotic-induced weight gain.
METHODS: We analyzed TSPO polymorphisms in 670 schizophrenia cases and 775 healthy controls. Gene-gene interactions between TSPO and other mitochondrial membrane protein-encoding genes (VDAC1 and ANT1) were explored. Positive findings were evaluated in two independent samples (Munich, n = 300; RUPP, n = 119).
RESULTS: TSPO rs6971 was independently associated with antipsychotic-induced weight gain in the discovery (puncor = 0.04) and RUPP samples (p = 3.00 × 10(-3)), and interacted with ANT1 rs10024068 in the discovery (p = 1.15 × 10(-3)) and RUPP samples (p = 2.76 × 10(-4)).
CONCLUSIONS: Our findings highlight TSPO as a candidate for future investigations of antipsychotic-induced weight gain, and support the involvement of mitochondrial membrane components in this serious treatment side effect.