Hello darkness, my old friend: 3-KETOACYL-COENZYME A SYNTHASE4 is a branch point in the regulation of triacylglycerol synthesis in Arabidopsis thaliana.

Plant lipids are important as alternative sources of carbon and energy when sugars or starch are limited. Here, we applied combined heat and darkness or extended darkness to a panel of ∼300 Arabidopsis (Arabidopsis thaliana) accessions to study lipid remodeling under carbon starvation. Natural allelic variation at 3-KETOACYL-COENZYME A SYNTHASE4 (KCS4), a gene encoding an enzyme involved in very long chain fatty acid (VLCFA) synthesis, underlies the differential accumulation of polyunsaturated triacylglycerols (puTAGs) under stress. Ectopic expression of KCS4 in yeast and plants proved that KCS4 is a functional enzyme localized in the endoplasmic reticulum with specificity for C22 and C24 saturated acyl-CoA. Allelic mutants and transient overexpression in planta revealed the differential role of KCS4 alleles in VLCFA synthesis and leaf wax coverage, puTAG accumulation, and biomass. Moreover, the region harboring KCS4 is under high selective pressure and allelic variation at KCS4 correlates with environmental parameters from the locales of Arabidopsis accessions. Our results provide evidence that KCS4 plays a decisive role in the subsequent fate of fatty acids released from chloroplast membrane lipids under carbon starvation. This work sheds light on both plant response mechanisms and the evolutionary events shaping the lipidome under carbon starvation.

Pathogenic variants of the coenzyme A biosynthesis-associated enzyme phosphopantothenoylcysteine decarboxylase cause autosomal-recessive dilated cardiomyopathy.

Coenzyme A (CoA) is an essential cofactor involved in a range of metabolic pathways including the activation of long-chain fatty acids for catabolism. Cells synthesize CoA de novo from vitamin B5 (pantothenate) via a pathway strongly conserved across prokaryotes and eukaryotes. In humans, it involves five enzymatic steps catalyzed by four enzymes: pantothenate kinase (PANK [isoforms 1-4]), 4'-phosphopantothenoylcysteine synthetase (PPCS), phosphopantothenoylcysteine decarboxylase (PPCDC), and CoA synthase (COASY). To date, inborn errors of metabolism associated with all of these genes, except PPCDC, have been described, two related to neurodegeneration with brain iron accumulation (NBIA), and one associated with a cardiac phenotype. This paper reports another defect in this pathway (detected in two sisters), associated with a fatal cardiac phenotype, caused by biallelic variants (p.Thr53Pro and p.Ala95Val) of PPCDC. PPCDC enzyme (EC 4.1.1.36) catalyzes the decarboxylation of 4'-phosphopantothenoylcysteine to 4'-phosphopantetheine in CoA biosynthesis. The variants p.Thr53Pro and p.Ala95Val affect residues highly conserved across different species; p.Thr53Pro is involved in the binding of flavin mononucleotide, and p.Ala95Val is likely a destabilizing mutation. Patient-derived fibroblasts showed an absence of PPCDC protein, and nearly 50% reductions in CoA levels. The cells showed clear energy deficiency problems, with defects in mitochondrial respiration, and mostly glycolytic ATP synthesis. Functional studies performed in yeast suggest these mutations to be functionally relevant. In summary, this work describes a new, ultra-rare, severe inborn error of metabolism due to pathogenic variants of PPCDC.

Vitamin B5, a coenzyme A precursor, rescues TANGO2 deficiency disease-associated defects in Drosophila and human cells.

Mutations in the Transport and Golgi Organization 2 (TANGO2) gene are associated with intellectual deficit, neurodevelopmental delay and regression. Individuals can also present with an acute metabolic crisis that includes rhabdomyolysis, cardiomyopathy, and cardiac arrhythmias, the latter of which are potentially lethal. While preventing metabolic crises has the potential to reduce mortality, no treatments currently exist for this condition. The function of TANGO2 remains unknown but is suspected to be involved in some aspect of lipid metabolism. Here, we describe a model of TANGO2-related disease in the fruit fly Drosophila melanogaster that recapitulates crucial disease traits. Pairing a new fly model with human cells, we examined the effects of vitamin B5, a coenzyme A (CoA) precursor, on alleviating the cellular and organismal defects associated with TANGO2 deficiency. We demonstrate that vitamin B5 specifically improves multiple defects associated with TANGO2 loss-of-function in Drosophila and rescues membrane trafficking defects in human cells. We also observed a partial rescue of one of the fly defects by vitamin B3, though to a lesser extent than vitamin B5. Our data suggest that a B complex supplement containing vitamin B5/pantothenate may have therapeutic benefits in individuals with TANGO2-deficiency disease. Possible mechanisms for the rescue are discussed that may include restoration of lipid homeostasis.

Full-length transcriptome sequencing provides insights into flavonoid biosynthesis in Camellia nitidissima Petals.

Flavonoids are the main medicinal ingredients in Camellia nitidissima, but the regulatory mechanism of flavonoid biosynthesis in flowers is unclear; therefore, the flavonoids in C. nitidissima have not been effectively used. The present study performed full-length transcriptome sequencing of C. nitidissima flower. Furthermore, the reported RNA-sequencing data of C. nitidissima petals were reanalyzed using the full-length transcriptome as a reference, and the regulatory mechanism of flavonoid synthesis in petals was elucidated. The analysis identified 43,350 isoforms annotated in non-redundant protein (Nr), Kyoto Encyclopedia of Genes and Genomes (KEGG), EuKaryotic Orthologous Groups (KOG), and Swiss-Prot databases, among which 34,602 aligned to Camellia sinensis genes. A total of 11,857 differentially expressed genes (DEGs), including 112 related to flavonoid synthesis, were identified by pairwise comparison. Subsequently, analysis of the phylogeny and the conserved motifs of R2R3-MYB using the proteins sequences identified three R2R3-MYB transcription factors that regulated flavonoid biosynthesis. Weighted gene co-expression network analysis (WGCNA) identified phenylalanine ammonia-lyase (PAL) and 4-coumarate: CoA ligase(4CL) as the hub genes and showed that bHLH79 interacted with PAL. Finally, validated the expression of seven DEGs involved in flavonoid biosynthesis using real-time quantitative PCR (qRT-PCR). Thus, the present study generated and used the full-length transcriptome as the reference to analyze the transcriptome of petals and proposed a possible regulatory mechanism of flavonoid synthesis in C. nitidissima. The study's findings unravel the genetic mechanisms underlying flavonoid synthesis and suggest candidate genes for the genetic improvement of C. nitidissima.

Bi-Allelic Mutations in Zebrafish pank2 Gene Lead to Testicular Atrophy and Perturbed Behavior without Signs of Neurodegeneration.

Coenzyme A (CoA) is an essential cofactor in all living organisms, being involved in a large number of chemical reactions. Sequence variations in pantothenate kinase 2 (PANK2), the first enzyme of CoA biosynthesis, are found in patients affected by Pantothenate Kinase Associated Neurodegeneration (PKAN), one of the most common forms of neurodegeneration, with brain iron accumulation. Knowledge about the biochemical and molecular features of this disorder has increased a lot in recent years. Nonetheless, the main culprit of the pathology is not well defined, and no treatment option is available yet. In order to contribute to the understanding of this disease and facilitate the search for therapies, we explored the potential of the zebrafish animal model and generated lines carrying biallelic mutations in the pank2 gene. The phenotypic characterization of pank2-mutant embryos revealed anomalies in the development of venous vascular structures and germ cells. Adult fish showed testicular atrophy and altered behavioral response in an anxiety test but no evident signs of neurodegeneration. The study suggests that selected cell and tissue types show a higher vulnerability to pank2 deficiency in zebrafish. Deciphering the biological basis of this phenomenon could provide relevant clues for better understanding and treating PKAN.

Overexpression of ß-Ketoacyl CoA Synthase 2B.1 from Chenopodium quinoa Promotes Suberin Monomers' Production and Salt Tolerance in Arabidopsis thaliana.

Very-long-chain fatty acids (VLCFAs) are precursors for the synthesis of various lipids, such as triacylglycerols, sphingolipids, cuticular waxes, and suberin monomers, which play important roles in plant growth and stress responses. However, the underlying molecular mechanism regulating VLCFAs' biosynthesis in quinoa (Chenopodium quinoa Willd.) remains unclear. In this study, we identified and functionally characterized putative 3-ketoacyl-CoA synthases (KCSs) from quinoa. Among these KCS genes, CqKCS2B.1 showed high transcript levels in the root tissues and these were rapidly induced by salt stress. CqKCS2B.1 was localized to the endoplasmic reticulum. Overexpression of CqKCS2B.1 in Arabidopsis resulted in significantly longer primary roots and more lateral roots. Ectopic expression of CqKCS2B.1 in Arabidopsis promoted the accumulation of suberin monomers. The occurrence of VLCFAs with C22-C24 chain lengths in the overexpression lines suggested that CqKCS2B.1 plays an important role in the elongation of VLCFAs from C20 to C24. The transgenic lines of overexpressed CqKCS2B.1 showed increased salt tolerance, as indicated by an increased germination rate and improved plant growth and survival under salt stress. These findings highlight the significant role of CqKCS2B.1 in VLCFAs' production, thereby regulating suberin biosynthesis and responses to salt stress. CqKCS2B.1 could be utilized as a candidate gene locus to breed superior, stress-tolerant quinoa cultivars.

High Expression of ACOT2 Predicts Worse Overall Survival and Abnormal Lipid Metabolism: A Potential Target for Acute Myeloid Leukemia.

Acyl-CoA thioesterase (ACOT) plays a considerable role in lipid metabolism, which is closely related to the occurrence and development of cancer, nevertheless, its role has not been fully elucidated in acute myeloid leukemia (AML). To explore the role of ACOT2 in AML and to provide a potential therapeutic target for AML, the expression pattern of ACOT was investigated based on the TNMplot, Gene Expression Profiling Interactive Analysis (GEPIA), and Cancer Cell Line Encyclopedia (CCLE) database, and diagnostic value, prognostic value, and clinical phenotype of ACOT were explored based on data from The Cancer Genome Atlas (TCGA). Functional annotation and enrichment analysis of the common targets between ACOT2 coexpressed and AML-related genes were further performed by Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) analyses. The protein-protein interaction (PPI) network of ACOT2 coexpressed genes and functional ACOT2-related metabolites association network were constructed based on GeneMANIA and Human Metabolome Database. Among ACOTs, ACOT2 was highly expressed in AML compared to normal control subjects according to TNMplot, GEPIA, and CCLE database, which was significantly associated with poor overall survival (OS) in AML (P=0.003). Moreover, ACOT2 exhibited excellent diagnostic efficiency for AML (AUC: 1.000) and related to French-American-British (FAB) classification and cytogenetics. GO, KEGG, and GSEA analyses of 71 common targets between ACOT2 coexpressed and AML-related genes revealed that ACOT2 is closely related to ACOT1, ACOT4, enoyl-acyl carrier protein reductase, mitochondrial (MECR), puromycin-sensitive aminopeptidase (NPEPPS), SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1), and long-chain fatty acid-CoA ligase 1 (ACSL1) in PPI network, and plays a significant role in lipid metabolism, that is, involved in fatty acid elongation and biosynthesis of unsaturated fatty acids. Collectively, the increase of ACOT2 may be an important characteristic of worse OS and abnormal lipid metabolism, suggesting that ACOT2 may become a potential therapeutic target for AML.

Mutations Associated with Pyrazinamide Resistance in Mycobacterium tuberculosis: A Review and Update.

Pyrazinamide (PZA) has remained a keystone of tuberculosis (TB) therapy, and it possesses high imperative sterilizing action that can facilitate reduction in the present chemotherapy regimen. The combination of PZA works both with first- and second-line TB drugs, notably fluoroquinolones, clofazimine, bedaquiline, delamanid and pretomanid. Pyrazinamide inhibits various targets that are involved in different cellular processes like energy production (pncA), trans-translation (rpsA) and pantothenate/coenzyme A (panD) which are required for persistence of the pathogen. It is well known that pncA gene encoding pyrazinamidase is involved in the transition of PZA into the active form of pyrazinoic acid, which implies that mutation in the pncA gene can develop PZA resistance in Mycobacterium tuberculosis (M. tuberculosis) strain leading to a major clinical and public health concern. Therefore, it is very crucial to understand its resistance mechanism and to detect it precisely to help in the management of the disease. Scope of this review is to have a deep understanding of molecular mechanism of PZA resistance with its multiple targets which would help study the association of mutations and its resistance in M. tuberculosis. This will in turn help learn about the resistance of PZA and develop more accurate molecular diagnostic tool for drug-resistant TB in future TB therapy.

Comparative Genotypic Analysis of RAPD and RFLP Markers for Molecular Variation Detection of Methicillin-Resistant Staphylococcus aureus Clinical Isolates.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) isolates are associated with various diseases ranged from mild superficial impairments to invasive infections. This study aimed to evaluate the ability of polymerase chain reaction (PCR) based methods namely, restriction fragment length polymorphism (RFLP) of the coa gene and random amplified polymorphic DNA (RAPD), to determine the genetic diversity of MRSA isolates. Materials and Methods: A total of 37 MRSA isolates were conventionally identified depending on their biochemical and microbiological culture characteristics. Genotypic confirmation was based on detection of the associated mecA gene. The genetic variation amongst MRSA isolates was evaluated following the coa gene-based RFLP and RAPD fingerprints. Results: Results illustrated that, the species specific coa gene was detected in all MRSA isolates. The irregular bands intensity, number, and molecular sizes of the PCR amplicons demonstrated the coa gene polymorphism. The incompatible AluI digestion patterns of these amplicons classified the tested MRSA isolates into 20 RFLP patterns which confirm the coa gene polymorphism. Additionally, the PCR-based RAPD analysis showed variable bands number with size range of approximately 130 bp to 4 kbp, which indicated the genetic variation of the tested MRSA isolates as it created 36 variable RAPD banding profiles. Conclusions: coa gene AluI enzymatic restriction sites, amongst the tested MRSA isolates, certify their genetic variation on the basis of the accurate but complicated and relatively expensive coa gene-based RFLP. Conversely, the results verified the excellent ability of the simple and cost-effective PCR-based RAPD analysis to discriminate between MRSA isolates without any preface data about the genome.

The PoLACS4 Gene May Participate in Drought Stress Resistance in Tree Peony (Paeonia ostii 'Feng Dan Bai').

The tree peony (Paeonia ostii 'Feng Dan Bai') has excellent drought tolerance. Although it has already been reported that the cuticle is an essential barrier against drought stress, the critical genes for cuticle resistance to drought remain unclear. However, the long-chain acyl-CoA synthetases (LACS) family of genes may be significant for the synthesis of cuticle wax. To test whether the LACS gene family is involved in cuticle response to drought stress in tree peony, we measure the thickness of cuticle stems and leaves alongside LACS enzyme activity. It is found that the cuticle thickens and the LACS enzyme increases with the maturation of stems and leaves, and there is a positive correlation between them. The LACS enzyme increases within 12 h under drought stress induced by polyethylene glycol (PEG). The transcriptome sequencing result (BioProject accession number PRJNA317164) is searched for, and a LACS gene with high expression is cloned. This gene has high homology and similarity with LACS4 from Arabidopsis thaliana. The gene is named PoLACS4. It is show to be highly expressed in mature leaves and peaks within 1 h under drought and salt stresses. All these results suggest that the LACS family of genes may be involved in cuticle response to drought stress and that PoLACS4 is a crucial gene which responds rapidly to drought in the tree peony.

Novel polymorphism of the HMGCR gene related to the risk of diabetes in premature triple-vessel disease patients.

BACKGROUND: Coronary heart disease and diabetes are highly interrelated and complex diseases. We proposed to investigate the association of genetic polymorphisms of the lipoprotein important regulatory genes Niemann-Pick C1-like 1 (NPC1L1) and 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with premature triple-vessel coronary disease (PTVD) with diabetes, blood glucose and body mass index. METHODS: Four single-nucleotide polymorphisms (SNPs) (rs11763759, rs4720470, rs2072183 and rs2073547) of NPC1L1 and three SNPs (rs12916, rs2303151 and rs4629571) of HMGCR were genotyped in 872 PTVD patients. RESULTS: After performing logistic regression analysis adjusted for age and sex, rs2303151 of HMGCR was related to the risk of diabetes in the dominance model (odds ratio = 1.35, 95% confidence interval = 1.01-1.80, p = 0.04). However, the four SNPs of NPC1L1 were not associated with the risk of diabetes. Further analyses showed that neither the above SNPs of NPC1L1, nor the SNPs of HMGCR were related to blood glucose and body mass index (all p > 0.05). CONCLUSIONS: We report that rs2303151 is a novel polymorphism of the HMGCR gene related to the risk of diabetes in PTVD patients, which suggests HMGCR may be a potential common targeted pathogenic pathways between coronary heart disease and diabetes.

Coenzyme A precursors flow from mother to zygote and from microbiome to host.

Coenzyme A (CoA) is essential for metabolism and protein acetylation. Current knowledge holds that each cell obtains CoA exclusively through biosynthesis via the canonical five-step pathway, starting with pantothenate uptake. However, recent studies have suggested the presence of additional CoA-generating mechanisms, indicating a more complex system for CoA homeostasis. Here, we uncovered pathways for CoA generation through inter-organismal flows of CoA precursors. Using traceable compounds and fruit flies with a genetic block in CoA biosynthesis, we demonstrate that progeny survive embryonal and early larval development by obtaining CoA precursors from maternal sources. Later in life, the microbiome can provide the essential CoA building blocks to the host, enabling continuation of normal development. A flow of stable, long-lasting CoA precursors between living organisms is revealed. This indicates the presence of complex strategies to maintain CoA homeostasis.

Association of Common and Rare Genetic Variation in the 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Gene and Cataract Risk.

Background Results from animal models and observational studies have raised concerns regarding the potential cataractogenic effects of statin treatment. We investigated whether common and rare genetic variants in HMGCR are associated with cataract risk, to gauge the likely long-term effects of statin treatment on lenticular opacities. Methods and Results We used genotyping data and exome sequencing data of unrelated European individuals in the UK Biobank to test the association between genetically proxied inhibition of HMGCR and cataract risk. First, we constructed an HMGCR genetic score consisting of 5 common variants weighted by their association with low-density lipoprotein cholesterol. Second, we analyzed exome sequencing data to identify carriers of predicted loss-of-function mutations in HMGCR. Common and rare variants in aggregate were then tested for association with cataract and cataract surgery. In an analysis of >402 000 individuals, a 38.7 mg/dL (1 mmol/L) reduction in low-density lipoprotein C by the HMGCR genetic score was associated with higher risk for cataract (odds ratio, 1.14 [95% CI, 1.00-1.39], P=0.045) and cataract surgery (odds ratio, 1.25 [95% CI, 1.06-1.48], P=0.009). Among 169 172 individuals with HMGCR sequencing data, we identified 32 participants (0.02%), who carried a rare HMGCR predicted loss-of-function variant. Compared with noncarriers, heterozygous carriers of HMGCR predicted loss-of-function had a higher risk of developing cataract (odds ratio, 4.54 [95% CI, 1.96-10.53], P=0.001) and cataract surgery (odds ratio, 5.27 [95% CI, 2.27-12.25], P=5.37×10-4). In exploratory analyses, we found no significant association between genetically proxied inhibition of PCSK9, NPC1L1, or circulating low-density lipoprotein cholesterol levels (P>0.05 for all) and cataract risk. Conclusions We found that genetically proxied inhibition of the HMGCR gene mimicking long-term statin treatment associated with higher risk of cataract. Clinical trials with longer follow-up are needed to confirm these findings.

Molecular and biochemical characterization of two 4-coumarate: CoA ligase genes in tea plant (Camellia sinensis).

KEY MESSAGE: Two 4-coumarate: CoA ligase genes in tea plant involved in phenylpropanoids biosynthesis and response to environmental stresses. Tea plant is rich in flavonoids benefiting human health. Lignin is essential for tea plant growth. Both flavonoids and lignin defend plants from stresses. The biosynthesis of lignin and flavonoids shares a key intermediate, 4-coumaroyl-CoA, which is formed from 4-coumaric acid catalyzed by 4-coumaric acid: CoA ligase (4CL). Herein, we report two 4CL paralogs from tea plant, Cs4CL1 and Cs4CL2, which are a member of class I and II of this gene family, respectively. Cs4CL1 was mainly expressed in roots and stems, while Cs4CL2 was mainly expressed in leaves. The promoter of Cs4CL1 had AC, nine types of light sensitive (LSE), four types of stress-inducible (SIE), and two types of meristem-specific elements (MSE). The promoter of Cs4CL2 also had AC and nine types of LSEs, but only had two types of SIEs and did not have MSEs. In addition, the LSEs varied in the two promoters. Based on the different features of regulatory elements, three stress treatments were tested to understand their expression responses to different conditions. The resulting data indicated that the expression of Cs4CL1 was sensitive to mechanical wounding, while the expression of Cs4CL2 was UV-B-inducible. Enzymatic assays showed that both recombinant Cs4CL1 and Cs4CL2 transformed 4-coumaric acid (CM), ferulic acid (FR), and caffeic acid (CF) to their corresponding CoA ethers. Kinetic analysis indicated that the recombinant Cs4CL1 preferred to catalyze CF, while the recombinant Cs4CL2 favored to catalyze CM. The overexpression of both Cs4CL1 and Cs4CL2 increased the levels of chlorogenic acid and total lignin in transgenic tobacco seedlings. In addition, the overexpression of Cs4CL2 consistently increased the levels of three flavonoid compounds. These findings indicate the differences of Cs4CL1 and Cs4CL2 in the phenylpropanoid metabolism.

Fine-mapping studies distinguish genetic risks for childhood- and adult-onset asthma in the HLA region.

BACKGROUND: Genome-wide association studies of asthma have revealed robust associations with variation across the human leukocyte antigen (HLA) complex with independent associations in the HLA class I and class II regions for both childhood-onset asthma (COA) and adult-onset asthma (AOA). However, the specific variants and genes contributing to risk are unknown. METHODS: We used Bayesian approaches to perform genetic fine-mapping for COA and AOA (n=9432 and 21,556, respectively; n=318,167 shared controls) in White British individuals from the UK Biobank and to perform expression quantitative trait locus (eQTL) fine-mapping in immune (lymphoblastoid cell lines, n=398; peripheral blood mononuclear cells, n=132) and airway (nasal epithelial cells, n=188) cells from ethnically diverse individuals. We also examined putatively causal protein coding variation from protein crystal structures and conducted replication studies in independent multi-ethnic cohorts from the UK Biobank (COA n=1686; AOA n=3666; controls n=56,063). RESULTS: Genetic fine-mapping revealed both shared and distinct causal variation between COA and AOA in the class I region but only distinct causal variation in the class II region. Both gene expression levels and amino acid variation contributed to risk. Our results from eQTL fine-mapping and amino acid visualization suggested that the HLA-DQA1*03:01 allele and variation associated with expression of the nonclassical HLA-DQA2 and HLA-DQB2 genes accounted entirely for the most significant association with AOA in GWAS. Our studies also suggested a potentially prominent role for HLA-C protein coding variation in the class I region in COA. We replicated putatively causal variant associations in a multi-ethnic cohort. CONCLUSIONS: We highlight roles for both gene expression and protein coding variation in asthma risk and identified putatively causal variation and genes in the HLA region. A convergence of genomic, transcriptional, and protein coding evidence implicates the HLA-DQA2 and HLA-DQB2 genes and HLA-DQA1*03:01 allele in AOA.

PtoMYB142, a poplar R2R3-MYB transcription factor, contributes to drought tolerance by regulating wax biosynthesis.

Drought is one of the main environmental factors that limit plant development and growth. Accordingly, plants have evolved strategies to prevent water loss under drought stress, such as stomatal closure, maintenance of root water uptake, enhancement of stem water transport, and synthesis and deposition of cuticular wax. However, the molecular evidence of cuticular wax biosynthesis regulation in response to drought is limited in woody plants. Here, we identified an MYB transcription factor, Populus tomentosa Carr. MYB transcription factor (PtoMYB142), in response to drought stress from P. tomentosa. Over-expression of PtoMYB142 (PtoMYB142-OE) resulted in increased wax accumulation in poplar leaves, and significantly enhanced drought resistance. We found that the expression of wax biosynthesis genes CER4 and 3-ketoacyl CoA synthase (KCS) were markedly induced under drought stress, and significantly up-regulated in PtoMYB142-OE lines. Biochemical analysis confirmed that PtoMYB142 could directly bind to the promoter of CER4 and KCS6, and regulate their expression in P. tomentosa. Taken together, this study reveals that PtoMYB142 regulates cuticular wax biosynthesis to adapt to water-deficient conditions.

Evolution, characterization, and immune response function of long-chain acyl-CoA synthetase genes in rainbow trout (Oncorhynchus mykiss) under hypoxic stress.

Long-chain acyl-CoA synthetases (Acsls), members of the acyl-activating enzyme superfamily, haves been systematically characterized in mammals and certain fishes, but the research on their involvement in reproductive development and hypoxic stress response in rainbow trout remains limited. In this study, we investigated the acsl gene structure and physical and chemical characteristics and the evolutionary relationship among acsl genes using the NCBI/Ensembl database. Using hypoxia treatment experiment, acsl gene expression in various organs and its regulation were investigated. A total of 11 acsl genes were identified in rainbow trout. Phylogenetic analyses found that acsl genes in rainbow trout were clustered into two clades: acsl3/4 and acsl1/2/5/6, and the additional gene duplication observed resulted from the third round of genome duplication unique to teleosts. Multiple sequence alignment and conserved motif analyses showed that the sequence of acsl proteins was highly conserved. Real-time quantitative PCR (RT-qPCR) showed that the acsl genes were highly expressed in immune tissues (liver and head kidney). Under hypoxia, the expression of acsl genes was upregulated, suggesting that they enhance the tolerance to hypoxia and are involved in the immune response in rainbow trout. Our study provides valuable insights into teleost evolution and effects of hypoxia on biological immunity and form a basis for further research on the functional characteristics of acsl genes.

Complex hereditary peripheral neuropathies caused by novel variants in mitochondrial-related nuclear genes.

Mitochondrial disorders are a group of clinically and genetically heterogeneous multisystem disorders and peripheral neuropathy is frequently described in the context of mutations in mitochondrial-related nuclear genes. This study aimed to identify the causative mutations in mitochondrial-related nuclear genes in suspected hereditary peripheral neuropathy patients. We enrolled a large Japanese cohort of clinically suspected hereditary peripheral neuropathy patients who were mutation negative in the prescreening of the known Charcot-Marie-Tooth disease-causing genes. We performed whole-exome sequencing on 247 patients with autosomal recessive or sporadic inheritance for further analysis of 167 mitochondrial-related nuclear genes. We detected novel bi-allelic likely pathogenic/pathogenic variants in four patients, from four mitochondrial-related nuclear genes: pyruvate dehydrogenase beta-polypeptide (PDHB), mitochondrial poly(A) polymerase (MTPAP), hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, beta subunit (HADHB), and succinate-CoA ligase ADP-forming beta subunit (SUCLA2). All these patients showed sensory and motor axonal polyneuropathy, combined with central nervous system or multisystem involvements. The pathological analysis of skeletal muscles revealed mild neurogenic changes without significant mitochondrial abnormalities. Targeted screening of mitochondria-related nuclear genes should be considered for patients with complex hereditary axonal polyneuropathy, accompanied by central nervous system dysfunctions, or with unexplainable multisystem disorders.

A phosphopantetheinyl transferase gene restricted to Porphyromonas.

The phosphopantetheinyl transferases (PPTases) catalyze the post-translational modification of carrier proteins (CPs) from fatty acid synthases (FASs) in primary metabolism and from polyketide synthases (PKSs) and non-ribosomal polypeptide synthases (NRPSs) in secondary metabolism. Based on the conserved sequence motifs and substrate specificities, two types (AcpS-type and Sfp-type) of PPTases have been identified in prokaryotes. We present here that Porphyromonas gingivalis, the keystone pathogen in chronic periodontitis, harbors merely one PPTase, namely PptP. Complementation and gene deletion experiments clearly show that PptP can replace the function of Escherichia coli AcpS and is essential for the growth of P. gingivalis. Purified PptP transfers the 4-phosphopantetheine moiety of CoA to inactive apo-acyl carrier protein (ACP) to form holo-ACP, which functions as an active carrier of the acyl intermediates of fatty acid synthesis. Moreover, PptP exhibits broad substrate specificity, modifying all ACP substrates tested and catalyzing the transfer of coenzyme A (CoA) derivatives. The lack of sequence alignment with known PPTases together with phylogenetic analyses revealed PptP as a new class of PPTases. Identification of the new PPTase gene pptP exclusive in Porphyromonas species reveals a potential target for treating P. gingivalis infections.

Massive iron accumulation in PKAN-derived neurons and astrocytes: light on the human pathological phenotype.

Neurodegeneration associated with defective pantothenate kinase-2 (PKAN) is an early-onset monogenic autosomal-recessive disorder. The hallmark of the disease is the massive accumulation of iron in the globus pallidus brain region of patients. PKAN is caused by mutations in the PANK2 gene encoding the mitochondrial enzyme pantothenate kinase-2, whose function is to catalyze the first reaction of the CoA biosynthetic pathway. To date, the way in which this alteration leads to brain iron accumulation has not been elucidated. Starting from previously obtained hiPS clones, we set up a differentiation protocol able to generate inhibitory neurons. We obtained striatal-like medium spiny neurons composed of approximately 70-80% GABAergic neurons and 10-20% glial cells. Within this mixed population, we detected iron deposition in both PKAN cell types, however, the viability of PKAN GABAergic neurons was strongly affected. CoA treatment was able to reduce cell death and, notably, iron overload. Further differentiation of hiPS clones in a pure population of astrocytes showed particularly evident iron accumulation, with approximately 50% of cells positive for Perls staining. The analysis of these PKAN astrocytes indicated alterations in iron metabolism, mitochondrial morphology, respiratory activity, and oxidative status. Moreover, PKAN astrocytes showed signs of ferroptosis and were prone to developing a stellate phenotype, thus gaining neurotoxic features. This characteristic was confirmed in iPS-derived astrocyte and glutamatergic neuron cocultures, in which PKAN glutamatergic neurons were less viable in the presence of PKAN astrocytes. This newly generated astrocyte model is the first in vitro disease model recapitulating the human phenotype and can be exploited to deeply clarify the pathogenetic mechanisms underlying the disease.