acetoacetyl-CoA Thiolase Research Articles

Crystal structure of a thiolase from Archaeal Pyrococcus furiosus and its in silico functional annotation

In most of the eukaryotes and archaea, isopentenyl pyrophosphate (IPP) and dimethyl allyl pyrophosphate (DMAPP) essential building blocks of all isoprenoids synthesized in the mevalonate pathway. Here, the first enzyme of this pathway, acetoacetyl CoA thiolase (PFC_04095) from an archaea Pyrococcus furiosus is structurally characterized. The crystal structure of PFC_04095 is determined at 2.7 Å resolution, and the crystal structure reveals the absence of catalytic acid/base cysteine in its active site, which is uncommon in thiolases. In place of cysteine, His285 of HDAF motif performs both protonation and abstraction of proton during the reaction. The crystal structure shows that the distance between Cys83 and His335 is 5.4 Å. So, His335 could not abstract a proton from nucleophilic cysteine (Cys83), resulting in the loss of enzymatic activity of PFC_04095. MD simulations of the docked PFC_04095-acetyl CoA complex show substrate binding instability to the active site pocket. Here, we have reported that the stable binding of acetyl CoA to the PFC_04095 pocket requires the involvement of three protein complexes, i.e., thiolase (PFC_04095), DUF35 (PFC_04100), and HMGCS (PFC_04090).

Investigating the role of aae-miR-34-5p in the regulation of juvenile hormone biosynthesis genes in the mosquito Aedes aegypti

Juvenile hormone (JH) controls the development and reproduction of insects. Therefore, a tight regulation of the expression of JH biosynthetic enzymes is critical. microRNAs (miRNAs) play significant roles in the post-transcriptional regulation of gene expression by interacting with complementary sequences in target genes. Previously, we reported that several miRNAs were differentially expressed during three developmental stages of Aedes aegypti mosquitoes with different JH levels (no JH, high JH, and low JH). One of these miRNAs was aae-miR-34-5p. In this study, we identified the presence of potential target sequences of aae-miR-34-5p in the transcripts of some genes encoding JH biosynthetic enzymes. We analysed the developmental expression patterns of aae-miR-34-5p and the predicted target genes involved in JH biogenesis. Increases in miRNA abundance were followed, with a delay, by decreases in transcript levels of target genes. Application of an inhibitor and a mimic of aae-miR-34-5p led respectively to increased and decreased levels of thiolase transcripts, which is one of the early genes of JH biosynthesis. Female adult mosquitoes injected with an aae-miR-34-5p inhibitor exhibited significantly increased transcript levels of three genes encoding JH biosynthetic enzymes, acetoacetyl-CoA thiolase (thiolase), farnesyl diphosphate phosphatase, and farnesal dehydrogenase. Overall, our results suggest a potential role of miRNAs in JH production by directly targeting genes involved in its biosynthesis.

Cholesterol Metabolism in Pancreatic Cancer.

Pancreatic cancer's substantial impact on cancer-related mortality, responsible for 8% of cancer deaths and ranking fourth in the US, persists despite advancements, with a five-year relative survival rate of only 11%. Forecasts predict a 70% surge in new cases and a 72% increase in global pancreatic cancer-related deaths by 2040. This review explores the intrinsic metabolic reprogramming of pancreatic cancer, focusing on the mevalonate pathway, including cholesterol biosynthesis, transportation, targeting strategies, and clinical studies. The mevalonate pathway, central to cellular metabolism, significantly shapes pancreatic cancer progression. Acetyl coenzyme A (Acetyl-CoA) serves a dual role in fatty acid and cholesterol biosynthesis, fueling acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) development. Enzymes, including acetoacetyl-CoA thiolase, 3-hydroxy-3methylglutaryl-CoA (HMG-CoA) synthase, and HMG-CoA reductase, are key enzymes in pancreatic cancer. Inhibiting HMG-CoA reductase, e.g., by using statins, shows promise in delaying PanIN progression and impeding pancreatic cancer. Dysregulation of cholesterol modification, uptake, and transport significantly impacts tumor progression, with Sterol O-acyltransferase 1 (SOAT1) driving cholesterol ester (CE) accumulation and disrupted low-density lipoprotein receptor (LDLR) expression contributing to cancer recurrence. Apolipoprotein E (ApoE) expression in tumor stroma influences immune suppression. Clinical trials targeting cholesterol metabolism, including statins and SOAT1 inhibitors, exhibit potential anti-tumor effects, and combination therapies enhance efficacy. This review provides insights into cholesterol metabolism's convergence with pancreatic cancer, shedding light on therapeutic avenues and ongoing clinical investigations.

Excessive Mitochondrial Fission Suppresses Mucosal Repair by Impairing Butyrate Metabolism in Colonocytes.

Mucosal healing is one of the principal therapeutic targets for ulcerative colitis (UC). Mitochondria are dynamic organelles that undergo constant fusion and fission; however, the process that is most conducive to mucosal healing remains unclear. This study investigated the role of mitochondrial fission in mucosal healing in UC patients. Quantitative polymerase chain reaction, Western blotting, and immunostaining were used to detect mitochondrial fission in UC patients and a dextran sulfate sodium-induced colitis model. Colonic organoids were used to investigate the role of mitochondrial fission in butyrate metabolism. Enzyme activity assays were performed to identify the key proteins involved in this mechanism. It was found that inhibition of mitochondrial fission promoted mucosal healing in mice and that there was an increase in mitochondrial fission in colonic epithelial cells of UC patients. Excessive fission inhibits stem cell proliferation by impairing butyrate metabolism in colonic organoids. The mitochondrial fission antagonist P110 failed to promote mucosal healing in antibiotic-treated mice, and the addition of exogenous butyrate reversed this effect. Increased butyrate exposure in the colonic stem cell niche has also been observed in UC patients. Mechanistically, enzyme activity assays on colonic organoids revealed that excessive fission inhibits mitochondrial acetoacetyl-CoA thiolase activity via reactive oxygen species. Collectively, these data indicate that excessive mitochondrial fission suppresses mucosal repair by inhibiting butyrate metabolism and provides a potential target for mucosal healing in patients with ulcerative colitis.

Ketone Bodies and Brain Metabolism: New Insights and Perspectives for Neurological Diseases.

Ketone Bodies and Brain Metabolism: New Insights and Perspectives for Neurological Diseases.

The Cytosolic Acetoacetyl-CoA Thiolase TaAACT1 Is Required for Defense against Fusarium pseudograminearum in Wheat.

Fusarium pseudograminearum is a major pathogen for the destructive disease Fusarium crown rot (FCR) of wheat (Triticum aestivum). The cytosolic Acetoacetyl-CoA thiolase II (AACT) is the first catalytic enzyme in the mevalonate pathway that biosynthesizes isoprenoids in plants. However, there has been no investigation of wheat cytosolic AACT genes in defense against pathogens including Fusarium pseudograminearum. Herein, we identified a cytosolic AACT-encoding gene from wheat, named TaAACT1, and demonstrated its positively regulatory role in the wheat defense response to F. pseudograminearum. One haplotype of TaAACT1 in analyzed wheat genotypes was associated with wheat resistance to FCR. The TaAACT1 transcript level was elevated after F. pseudograminearum infection, and was higher in FCR-resistant wheat genotypes than in susceptible wheat genotypes. Functional analysis indicated that knock down of TaAACT1 impaired resistance against F. pseudograminearum and reduced the expression of downstream defense genes in wheat. TaAACT1 protein was verified to localize in the cytosol of wheat cells. TaAACT1 and its modulated defense genes were rapidly responsive to exogenous jasmonate treatment. Collectively, TaAACT1 contributes to resistance to F. pseudograminearum through upregulating the expression of defense genes in wheat. This study sheds new light on the molecular mechanisms underlying wheat defense against FCR.

Hepatic Acat2 overexpression promotes systemic cholesterol metabolism and adipose lipid metabolism in mice

Aims/hypothesisAcetyl coenzyme A acetyltransferase (ACAT), also known as acetoacetyl-CoA thiolase, catalyses the formation of acetoacetyl-CoA from acetyl-CoA and forms part of the isoprenoid biosynthesis pathway. Thus, ACAT plays a central role in cholesterol metabolism in a variety of cells. Here, we aimed to assess the effect of hepatic Acat2 overexpression on cholesterol metabolism and systemic energy metabolism.MethodsWe generated liver-targeted adeno-associated virus 9 (AAV9) to achieve hepatic Acat2 overexpression in mice. Mice were injected with AAV9 through the tail vein and subjected to morphological, physiological (body composition, indirect calorimetry, treadmill, GTT, blood biochemistry, cardiac ultrasonography and ECG), histochemical, gene expression and metabolomic analysis under normal diet or feeding with high-fat diet to investigate the role of ACAT2 in the liver.ResultsHepatic Acat2 overexpression reduced body weight and total fat mass, elevated the metabolic rate, improved glucose tolerance and lowered the serum cholesterol level of mice. In addition, the overexpression of Acat2 inhibited fatty acid, glucose and ketone metabolic pathways but promoted cholesterol metabolism and changed the bile acid pool and composition of the liver. Hepatic Acat2 overexpression also decreased the size of white adipocytes and promoted lipid metabolism in white adipose tissue. Furthermore, hepatic Acat2 overexpression protected mice from high-fat-diet-induced weight gain and metabolic defectsConclusions/interpretationOur study identifies an essential role for ACAT2 in cholesterol metabolism and systemic energy expenditure and provides key insights into the metabolic benefits of hepatic Acat2 overexpression. Thus, adenoviral Acat2 overexpression in the liver may be a potential therapeutic tool in the treatment of obesity and hypercholesterolaemia.Graphical abstract

Engineering the oleaginous yeast Candida tropicalis for α-humulene overproduction

Backgroundα-Humulene is a plant-derived monocyclic sesquiterpenoid with multiple pharmacological activities, and far-reaching potential for the development of new drugs. Currently, the production of α-humulene is typically achieved via plant extraction, which is not sustainable and limited by low yields. The oleaginous yeast Candida tropicalis has recently emerged as a valuable host for producing high-value-added chemicals. However, the potential of C. tropicalis for terpenoid production has not been exploited.ResultsIn this study, C. tropicalis was engineered for de novo synthesis of α-humulene from glucose. To improve α-humulene production, the codon-optimised α-humulene synthase gene and the entire endogenous farnesyl diphosphate synthesis pathway were co-overexpressed. Furthermore, bottlenecks in the α-humulene synthase pathway were identified and relieved by overexpressing α-humulene synthase, acetoacetyl-CoA thiolase and NADH-dependent HMG-CoA reductase. Combined with fermentation medium optimisation, the engineered strain produced 195.31 mg/L of α-humulene in shake flasks and 4115.42 mg/L in a bioreactor through fed-batch fermentation, a 253- and 5345-fold increase over the initial production, respectively.ConclusionsThis study demonstrates the potential of C. tropicalis for α-humulene production, and presents a platform for the biosynthesis of other terpenoids.

Engineering a Balanced Acetyl Coenzyme A Metabolism in Saccharomyces cerevisiae for Lycopene Production through Rational and Evolutionary Engineering.

Saccharomyces cerevisiae is increasingly being used for the production of chemicals derived from acetyl coenzyme A (acetyl-CoA). However, the inadequate supply of cytosolic acetyl-CoA often leads to low yields. Here, we developed a novel strategy for balancing acetyl-CoA metabolism and increasing the amount of the downstream product. First, the combination of acetaldehyde dehydrogenase (eutE) and acetoacetyl-CoA thiolase (AtoB) was optimized to redirect the acetyl-CoA flux toward the target pathway, with a 21-fold improvement in mevalonic acid production. Second, pathway engineering and evolutionary engineering were conducted to attenuate the growth deficiency, and a 10-fold improvement of the maximum productivity was achieved. Third, acetyl-CoA carboxylase (ACC1) was dynamically downregulated as the complementary acetyl-CoA pathway, and the yield was improved more than twofold. Fourth, the most efficient and complementary acetyl-CoA pathways were combined, and the final strain produced 68 mg/g CDW lycopene, which was among the highest yields reported in S. cerevisiae. This study demonstrates a new method of producing lycopene products by regulating acetyl-CoA metabolism.

Isolation, sequencing and expression of the gene encoding acetoacetyl-coa thiolase from Panax vietnamensis Ha et Grushv.

Panax vietnamensis Ha et Grushv., naturally distributed in Ngoc Linh Mountain, is an endemic Panax species of Vietnam. For centuries, P. vietnamensis has been used in traditional folk medicine to treat many serious diseases or enhance physical strength. Ginsenosides are responsible for most of the medicinal effects of the Panax species. Acetoacetyl-CoA thiolase (AACT) is considered as an important enzyme involved in the biosynthesis of ginsenoside. In this study, a full-length cDNA of the gene encoding AACT protein (GeneBank accession number MZ272018) was obtained from P. vietnamensis using reverse transcription PCR. The gene open reading frame (1224 bp) encodes 408 amino acids. This cDNA sequence is 99.08% similar to the cDNA sequence of Panax notoginseng (KJ804173.1). The functional analysis of its protein by InterPro showed that the structure of AACT monomer consists of three domains, including thiolase-like domain (17-285), N-terminal (18-276), and C-terminal (286-406). Although there were some differences in the nucleotide sequence of the AACT cDNA gene between P. vietnamensis and the reference species, all important domains and sites related to the thiolase activity were observed. Phylogenetic analysis using AACT cDNA gene sequence revealed a close relationship of P. vietnamensis with P. notoginseng and Trachyspemum ammi. The quantitative real-time PCR results indicated the expression of AACT gene of P. vietnamensis depended on types of tissue and plant developmental stages (1, 4, 6 and 11 years old). The gene was expressed at higher levels in roots than in leaves and the highest expression of AACT gene was detected in the 11-year-old roots. The results provided valuable information for further studies on the biosynthesis of ginsenoside in P. vietnamensis in particular and Panax species in general.

Quantitative proteomic analysis of the sugarcane defense responses incited by Acidovorax avenae subsp. avenae causing red stripe

The causal agent of red stripe, Acidovorax avenae subsp. avenae (Aaa), can incite significant economic losses during sugarcane production. Proteomics is a useful tool for the comprehensive identification of defense response proteins in plants. In this study, isobaric tags for relative and absolute quantification (iTRAQ)-based proteomics was used to identify proteins that were produced in sugarcane in defense to Aaa in two Saccharum spp. cultivars: ROC22 (resistant to red stripe) and MT11−610 (susceptible). Defense response was evaluated at 0 h (mock-inoculation) and 24 h after inoculation with the bacterial pathogen, and 10,502 high-confidence proteins and 1962 differentially expressed proteins (DEPs) were identified. These DEPs included 1027 proteins (671 upregulated, 354 downregulated) in ROC22 and 1130 proteins (566 upregulated, 564 downregulated) in MT11−610. Gene ontology analysis revealed that most DEPs were clustered in the metabolic, single-organism metabolic, and oxidation-reduction processes, and in catalytic activity. In a KEGG analysis, these proteins belonged to common pathways such as secondary metabolite biosynthesis and biosynthesis of phenylpropanoids. Thirty-six DEPs were identified, especially epoxide hydrolase 1, dynamin-related protein 1C-like, cytochrome oxidase subunit I, FK506-binding protein, acetoacetyl CoA thiolase isoform 2, anthocyanidin 3-o-glucosyltransferase, ubiquitin carboxyl-terminal hydrolase 4, protein disulfide isomerase-like protein, and jumonji-like transcription factor family protein. These nine proteins were characterized by enhanced expression with ≥1.5-fold increases in resistant ROC22 versus susceptible MT11−610, and are therefore biomarker candidates in the sugarcane response against Aaa. These data could be very useful in molecular breeding for sugarcane resistance to red stripe.

Revealing of sugar utilization systems in Halomonas sp. YLGW01 and application for poly(3-hydroxybutyrate) production with low-cost medium and easy recovery

Poly(3-hydroxybutyrate) (PHB) is a common polyhydroxyalkanoate (PHA) with potential as an alternative for petroleum-based plastics. Previously, we reported a new strain, Halomonas sp. YLGW01, which hyperproduces PHB with 94% yield using fructose. In this study, we examined the PHB production machinery of Halomonas sp. YLGW01 in more detail by deep-genome sequencing, which revealed a 3,453,067-bp genome with 65.1% guanine-cytosine content and 3054 genes. We found two acetyl-CoA acetyltransferases (Acetoacetyl-CoA thiolase, PhaA), one acetoacetyl-CoA reductase (PhaB), two PHB synthases (PhaC1, PhaC2), PHB depolymerase (PhaZ), and Enoyl-CoA hydratase (PhaJ) in the genome, along with two fructose kinases and fructose transporter systems, including the phosphotransferase system (PTS) and ATP-binding transport genes. We then examined the PHB production by Halomonas sp. YLGW01 using high-fructose corn syrup (HFCS) containing fructose, glucose, and sucrose in sea water medium, resulting in 7.95 ± 0.11 g/L PHB (content, 67.39 ± 0.34%). PHB was recovered from Halomonas sp. YLGW01 using different detergents; the use of Tween 20 and SDS yielded micro-sized granules with high purity. Overall, these results reveal the distribution of PHB synthetic genes and the sugar utilization system in Halomonas sp. YLGW01 and suggest a possible method for PHB recovery.

Isolation and expression of five genes in the mevalonate pathway of the Chinese white pine beetle, Dendroctonus armandi (Curculionidae: Scolytinae).

The Chinese white pine beetle Dendroctonus armandi (Tsai and Li) is a significant pest of the Qinling and Bashan Mountains pine forests of China. The Chinese white pine beetle can overcome the defences of Chinese white pine Pinus armandi (Franch) through pheromone-assisted aggregation that results in a mass attack of host trees. We isolated five full-length complementary DNAs encoding mevalonate pathway-related enzyme genes from the Chinese white pine beetle (D. armandi), which are acetoacetyl-CoA thiolase (AACT), geranylgeranyl diphosphate synthase (GGPPS), mevalonate kinase (MK), mevalonate diphosphate decarboxylase (MPDC), and phosphomevalonate kinase (PMK). Bioinformatic analyses were performed on the full-length deduced amino acid sequences. Differential expression of these five genes was observed between sexes, and within these significant differences among topically applied juvenile hormone III (JH III), fed on phloem of P. armandi, tissue distribution, and development stage. Mevalonate pathway genes expression were induced by JH III and feeding.

Advanced Strategies for Production of Natural Products in Yeast.

Natural products account for more than 50% of all small-molecule pharmaceutical agents currently in clinical use. However, low availability often becomes problematic when a bioactive natural product is promising to become a pharmaceutical or leading compound. Advances in synthetic biology and metabolic engineering provide a feasible solution for sustainable supply of these compounds. In this review, we have summarized current progress in engineering yeast cell factories for production of natural products, including terpenoids, alkaloids, and phenylpropanoids. We then discuss advanced strategies in metabolic engineering at three different dimensions, including point, line, and plane (corresponding to the individual enzymes and cofactors, metabolic pathways, and the global cellular network). In particular, we comprehensively discuss how to engineer cofactor biosynthesis for enhancing the biosynthesis efficiency, other than the enzyme activity. Finally, current challenges and perspective are also discussed for future engineering direction.

Structural basis for differentiation between two classes of thiolase: Degradative vs biosynthetic thiolase

Thiolases are a well characterized family of enzymes with two distinct categories: degradative, β-ketoadipyl-CoA thiolases and biosynthetic, acetoacetyl-CoA thiolases. Both classes share an identical catalytic triad but catalyze reactions in opposite directions. Moreover, it is established that in contrast to the biosynthetic thiolases the degradative thiolases can accept substrates with broad chain lengths. Hitherto, no residue or structural pattern has been recognized that might help to discern the two thiolases, here we exploit, a tetrameric degradative thiolase from Pseudomonas putida KT2440 annotated as PcaF, as a model system to understand features which distinguishes the two classes using structural studies and bioinformatics analyses. Degradative thiolases have different active site architecture when compared to biosynthetic thiolases, demonstrating the dissimilar chemical nature of the active site architecture. Both thiolases deploy different “anchoring residues” to tether the large Coenzyme A (CoA) or CoA derivatives. Interestingly, the H356 of the catalytic triad in PcaF is directly involved in tethering the CoA/CoA derivatives into the active site and we were able to trap a gridlocked thiolase structure of the H356A mutant, where the CoA was found to be covalently linked to the catalytic cysteine residue, inhibiting the overall reaction. Further, X-ray structures with two long chain CoA derivatives, hexanal-CoA and octanal-CoA helped in delineating the long tunnel of 235 Å2 surface area in PcaF and led to identification of a unique covering loop exclusive to degradative thiolases that plays an active role in determining the tunnel length and the nature of the binding substrate.

The Differential Expression of Mevalonate Pathway Genes in the Gut of the Bark Beetle Dendroctonus rhizophagus (Curculionidae: Scolytinae) Is Unrelated to the de Novo Synthesis of Terpenoid Pheromones.

Bark beetles commonly produce de novo terpenoid pheromones using precursors synthesized through the mevalonate pathway. This process is regulated by Juvenile Hormone III (JH III). In this work, the expression levels of mevalonate pathway genes were quantified after phloem feeding—to induce the endogenous synthesis of JH III—and after the topical application of a JH III solution. The mevalonate pathway genes from D. rhizophagus were cloned, molecularly characterized, and their expression levels were quantified. Also, the terpenoid compounds produced in the gut were identified and quantified by Gas Chromatography Mass Spectrometry (GC-MS). The feeding treatment produced an evident upregulation, mainly in acetoacetyl-CoA thiolase (AACT), 3-hydroxy-3-methylglutaryl-CoA synthase (HMGS), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), phosphomevalonate kinase (PMK), and isopentenyl diphosphate isomerase (IPPI) genes, and males reached higher expression levels compared to females. In contrast, the JH III treatment did not present a clear pattern of upregulation in any sex or time. Notably, the genes responsible for the synthesis of frontalin and ipsdienol precursors (geranyl diphosphate synthase/farnesyl diphosphate synthase (GPPS/FPPS) and geranylgeranyl diphosphate synthase (GGPPS)) were not clearly upregulated, nor were these compounds further identified. Furthermore, trans-verbenol and myrtenol were the most abundant compounds in the gut, which are derived from an α-pinene transformation rather than de novo synthesis. Hence, the expression of mevalonate pathway genes in D. rhizophagus gut is not directed to the production of terpenoid pheromones, regardless of their frequent occurrence in the genus Dendroctonus.

Mutation update on ACAT1 variants associated with mitochondrial acetoacetyl-CoA thiolase (T2) deficiency.

Mitochondrial acetoacetyl‐CoA thiolase (T2, encoded by the ACAT1 gene) deficiency is an inherited disorder of ketone body and isoleucine metabolism. It typically manifests with episodic ketoacidosis. The presence of isoleucine‐derived metabolites is the key marker for biochemical diagnosis. To date, 105 ACAT1 variants have been reported in 149 T2‐deficient patients. The 56 disease‐associated missense ACAT1 variants have been mapped onto the crystal structure of T2. Almost all these missense variants concern residues that are completely or partially buried in the T2 structure. Such variants are expected to cause T2 deficiency by having lower in vivo T2 activity because of lower folding efficiency and/or stability. Expression and activity data of 30 disease‐associated missense ACAT1 variants have been measured by expressing them in human SV40‐transformed fibroblasts. Only two variants (p.Cys126Ser and p.Tyr219His) appear to have equal stability as wild‐type. For these variants, which are inactive, the side chains point into the active site. In patients with T2 deficiency, the genotype does not correlate with the clinical phenotype but exerts a considerable effect on the biochemical phenotype. This could be related to variable remaining residual T2 activity in vivo and has important clinical implications concerning disease management and newborn screening.

Molecular identification and expression of sesquiterpene pathway genes responsible for patchoulol biosynthesis and regulation in Pogostemon cablin

BackgroundMany commercially important drug and flavor compounds are secondary metabolites of terpenoid origin. Pogostemon cablin, a commercially important industrial and medicinal crop, accumulates abundant patchouli oil comprised of more than 24 unique sesquiterpene compounds, with the most abundant being patchouli alcohol.ResultsIn this study, we analyzed the P. cablin transcriptome library, obtaining 74 terpenoid biosynthesis-related genes, and identified their expression patterns in leaves, stems, and flowers. These genes are members of 15 different families, and we detected all the enzymes involved in the sesquiterpenes pathway that are responsible for patchoulol biosynthesis. Sequence structure, homology, conserved domain properties, and phylogeny of certain identified genes were systematically investigated. Color complementation assay was used to verify the functional activity of the MEP pathway proteins. Exogenous hormone treatment revealed that patchoulol synthesis is induced by methyl jasmonate (MeJA). Quantitative reverse-transcription PCR analysis indicated that the MVA pathway genes (acetoacetyl-CoA thiolase, 3-hydroxy-3-methylglutaryl-coenzyme A reductase, mevalonate diphosphate decarboxylase, and farnesyl diphosphate synthase) participate in patchoulol biosynthesis and are mediated by MeJA.ConclusionsTaken together, this is the first report of integrated analysis of P. cablin MVA and MEP pathway related genes, providing a better understanding of terpenoid and/or patchoulol biosynthesis in P. cablin, and the basis for improving patchoulol production through genetic engineering.

Two Infants With Beta-Ketothiolase Deficiency Identified by Newborn Screening in China.

Beta-ketothiolase deficiency (BKTD) is an autosomal recessive disease caused by a defect of mitochondrial acetoacetyl-CoA thiolase. Beginning in 2014, we carried out newborn screening by tandem mass spectrometry (MS/MS) followed by next-generation sequencing (NGS) and identified two infants with BKTD among 203,750 newborns born in Jiangsu Province, China. Both infants showed the characteristic chemical abnormalities of BKTD. We used NGS to confirm variants in the ACAT1. Patient 1 had the compound heterozygous variants c.721dupA and c.928G > C. Patient 2 had compound heterozygosity for the c.238+1G > A and c.1163G > T variants. c.721dupA, c.928G > C and c.1163G > T were suspected to be likely pathogenic, whereas c.238+1G > A was determined to be pathogenic. None of the four variants have been reported in the literature. Patient 1 presented with onset of metabolic acidosis and neonatal hypoglycemia 8 days after birth, whereas patient 2 was detected through neonatal disease screening but had no clinical manifestations. These findings contribute to our understanding of the clinical characteristics and genetic basis of BKTD.

Recent advances in understanding beta-ketothiolase (mitochondrial acetoacetyl-CoA thiolase, T2) deficiency.

Beta-ketothiolase (mitochondrial acetoacetyl-CoA thiolase, T2) deficiency (OMIM #203750, *607809) is an inborn error of metabolism that affects isoleucine catabolism and ketone body metabolism. This disorder is clinically characterized by intermittent ketoacidotic crises under ketogenic stresses. In addition to a previous 26-case series, four series of T2-deficient patients were recently reported from different regions. In these series, most T2-deficient patients developed their first ketoacidotic crises between the ages of 6 months and 3 years. Most patients experienced less than three metabolic crises. Newborn screening (NBS) for T2 deficiency is performed in some countries but some T2-deficient patients have been missed by NBS. Therefore, T2 deficiency should be considered in patients with severe metabolic acidosis, even in regions where NBS for T2 deficiency is performed. Neurological manifestations, especially extrapyramidal manifestations, can occur as sequelae to severe metabolic acidosis; however, this can also occur in patients without any apparent metabolic crisis or before the onset of metabolic crisis.