Search

Background and Aim: Lipid metabolism disorder is the primary feature of numerous refractory chronic diseases. Fatty acid oxidation, an essential aerobic biological process, is closely related to the progression of NAFLD. The forkhead transcription factor FOXO1 has been reported to play an important role in lipid metabolism. However, the molecular mechanism through which FOXO1 regulates fatty acid oxidation remains unclear. Methods: Transcriptomic analysis was performed to examine the cellular expression profile to determine the functional role of FOXO1 in HepG2 cells with palmitic acid (PA)‐induced lipid accumulation. FOXO1‐binding motifs at the promoter region of aldehyde dehydrogenase 1 family member L2 (ALDH1L2) were predicted via bioinformatic analysis and confirmed via luciferase reporter assay. Overexpression of ALDH1L2 was induced to recover the impaired fatty acid oxidation in FOXO1‐knockout cells. Results: Knockout of FOXO1 aggravated lipid deposition in hepatic cells. Transcriptomic profiling revealed that knockout of FOXO1 increased the expression of genes associated with fatty acid synthesis but decreased the expression of carnitine palmitoyltransferase1a (CPT1α) and adipose triglyceride lipase (ATGL), which contribute to fatty acid oxidation. Mechanistically, FOXO1 was identified as a transcription factor of ALDH1L2. Knockout of FOXO1 significantly decreased the protein expression of ALDH1L2 and CPT1α in vitro and in vivo. Furthermore, overexpression of ALDH1L2 restored fatty acid oxidation in FOXO1‐knockout cells. Conclusion: The findings of this study indicate that FOXO1 modulates fatty acid oxidation by targeting ALDH1L2. [ABSTRACT FROM AUTHOR]

ALDH1L2, a mitochondrial enzyme in folate metabolism, converts 10‐formyl‐THF (10‐formyltetrahydrofolate) to THF (tetrahydrofolate) and CO2. At the cellular level, deficiency of this NADP+‐dependent reaction results in marked reduction in NADPH/NADP+ ratio and reduced mitochondrial ATP. Thus far, a single patient with biallelic ALDH1L2 variants and the phenotype of a neurodevelopmental disorder has been reported. Here, we describe another patient with a neurodevelopmental disorder associated with a novel homozygous missense variant in ALDH1L2, Pro133His. The variant caused marked reduction in the ALDH1L2 enzyme activity in skin fibroblasts derived from the patient as probed by 10‐FDDF, a stable synthetic analog of 10‐formyl‐THF. Additional associated abnormalities in these fibroblasts include reduced NADPH/NADP+ ratio and pool of mitochondrial ATP, upregulated autophagy and dramatically altered metabolomic profile. Overall, our study further supports a link between ALDH1L2 deficiency and abnormal neurodevelopment in humans. [ABSTRACT FROM AUTHOR]

Previously, the in vitro growth of cancer stem cells in the form of tumor spheres from five different brain cancer cell lines was found to be methionine-dependent. As this earlier work indicated that ALDH1L2, a folate-dependent mitochondria aldehyde dehydrogenase gene, is upregulated in glioblastoma stem cells, we invalidated this gene using CRISPR-cas 9 technique in this present work. We reported here that this invalidation was effective in U251 glioblastoma cells, and no cas9 off target site could be detected by genome sequencing of the two independent knockout targeting either exon I or exon III. The knockout of ALDH1L2 gene in U251 cells rendered the growth of the cancer stem cells of U251 methionine independent. In addition, a much higher ROS (reactive oxygen radicals) level can be detected in the knockout cells compared to the wild type cells. Our evidence here linked the excessive ROS level of the knockout cells to reduced total cellular NADPH. Our evidence suggested also that the cause of the slower growth of the knockout turmor sphere may be related to its partial differentiation. [ABSTRACT FROM AUTHOR]

Abstract Background Mitochondrial folate enzyme ALDH1L2 (aldehyde dehydrogenase 1 family member L2) converts 10-formyltetrahydrofolate to tetrahydrofolate and CO2 simultaneously producing NADPH. We have recently reported that the lack of the enzyme due to compound heterozygous mutations was associated with neuro-ichthyotic syndrome in a male patient. Here, we address the role of ALDH1L2 in cellular metabolism and highlight the mechanism by which the enzyme regulates lipid oxidation. Methods We generated Aldh1l2 knockout (KO) mouse model, characterized its phenotype, tissue histology, and levels of reduced folate pools and applied untargeted metabolomics to determine metabolic changes in the liver, pancreas, and plasma caused by the enzyme loss. We have also used NanoString Mouse Inflammation V2 Code Set to analyze inflammatory gene expression and evaluate the role of ALDH1L2 in the regulation of inflammatory pathways. Results Both male and female Aldh1l2 KO mice were viable and did not show an apparent phenotype. However, H&E and Oil Red O staining revealed the accumulation of lipid vesicles localized between the central veins and portal triads in the liver of Aldh1l2 -/- male mice indicating abnormal lipid metabolism. The metabolomic analysis showed vastly changed metabotypes in the liver and plasma in these mice suggesting channeling of fatty acids away from β-oxidation. Specifically, drastically increased plasma acylcarnitine and acylglycine conjugates were indicative of impaired β-oxidation in the liver. Our metabolomics data further showed that mechanistically, the regulation of lipid metabolism by ALDH1L2 is linked to coenzyme A biosynthesis through the following steps. ALDH1L2 enables sufficient NADPH production in mitochondria to maintain high levels of glutathione, which in turn is required to support high levels of cysteine, the coenzyme A precursor. As the final outcome, the deregulation of lipid metabolism due to ALDH1L2 loss led to decreased ATP levels in mitochondria. Conclusions The ALDH1L2 function is important for CoA-dependent pathways including β-oxidation, TCA cycle, and bile acid biosynthesis. The role of ALDH1L2 in the lipid metabolism explains why the loss of this enzyme is associated with neuro-cutaneous diseases. On a broader scale, our study links folate metabolism to the regulation of lipid homeostasis and the energy balance in the cell.

Mitochondrial dysfunction plays an important role in acute kidney injury (AKI). Thus, the agents improving the mitochondrial function could be beneficial for treating AKI. Ursodeoxycholic acid (UDCA) has been demonstrated to prevent mitochondrial dysfunction under pathology, however, its role in AKI and the underlying mechanism remain unknown. This study aimed to evaluate the effect of UDCA on cisplatin-induced AKI. In vivo , C57BL/6 J mice were treated with cisplatin (25 mg/kg) for 72 h to induce AKI through a single intraperitoneal (i.p.) injection with or without UDCA (60 mg/kg/day) administration by gavage. Renal function, mitochondrial function and oxidative stress were analyzed to evaluate kidney injury. In vitro , mouse proximal tubular cells (mPTCs) and human proximal tubule epithelial cells (HK2) were treated with cisplatin with or without UDCA treatment for 24 h. Transcriptomic RNA-seq was preformed to analyze possible targets of UDCA. Our results showed that cisplatin-induced increments of serum creatinine (Scr), blood urea nitrogen (BUN), and cystatin C were significantly reduced by UDCA along with ameliorated renal tubular injury evidenced by improved renal histology and blocked upregulation of neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule 1 (KIM-1). Meanwhile, the apoptosis induced by cisplatin was also markedly attenuated by UDCA administration. In vitro , UDCA treatment protected against tubular cell apoptosis possibly through antagonizing mitochondrial dysfunction and oxidative stress by targeting ALDH1L2 which was screened out by an RNA-seq analysis. Knockout of ALDH1L2 by CRISPR/Cas9 greatly blunted the protective effects of UDCA in renal tubular cells. Moreover, UDCA did not diminish cisplatin's antineoplastic effect in human cancer cells. In all, our results demonstrated that UDCA protects against cisplatin-induced AKI through improving mitochondrial function through acting on the expression of ALDH1L2, suggesting a clinical potential of UDCA for the treatment of AKI. Image 1 • Ursodeoxycholic acid (UDCA) ameliorated cisplatin-induced acute kidney injury. • UDCA protected against cisplatin-induced mitochondrial dysfunction. • UDCA protected against redox imbalance induced by cisplatin in renal tubule cells through acting on ALDH1L2. [ABSTRACT FROM AUTHOR]

Folate-mediated one-carbon metabolism (FOCM) is crucial in sustaining rapid proliferation and survival of cancer cells. The folate cycle depends on a series of key cellular enzymes, including aldehyde dehydrogenase 1 family member L2 (ALDH1L2) that is usually overexpressed in cancer cells, but the regulatory mechanism of ALDH1L2 remains undefined. In this study, we observed the significant overexpression of ALDH1L2 in colorectal cancer (CRC) tissues, which is associated with poor prognosis. Mechanistically, we identified that the acetylation of ALDH1L2 at the K70 site is an important regulatory mechanism inhibiting the enzymatic activity of ALDH1L2 and disturbing cellular redox balance. Moreover, we revealed that sirtuins 3 (SIRT3) directly binds and deacetylates ALDH1L2 to increase its activity. Interestingly, the chemotherapeutic agent 5-fluorouracil (5-Fu) inhibits the expression of SIRT3 and increases the acetylation levels of ALDH1L2 in colorectal cancer cells. 5-Fu-induced ALDH1L2 acetylation sufficiently inhibits its enzymatic activity and the production of NADPH and GSH, thereby leading to oxidative stress-induced apoptosis and suppressing tumor growth in mice. Furthermore, the K70Q mutant of ALDH1L2 sensitizes cancer cells to 5-Fu both in vitro and in vivo through perturbing cellular redox and serine metabolism. Our findings reveal an unknown 5-Fu-SIRT3-ALDH1L2 axis regulating redox homeostasis, and suggest that targeting ALDH1L2 is a promising therapeutic strategy to sensitize tumor cells to chemotherapeutic agents., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The expression levels of one-carbon metabolic enzymes were investigated and observed to be correlated with clinicopathological parameters in patients with pancreatic cancer. Mitochondrial one-carbon metabolism comprises a network of biological reactions that integrate nutrient status with nucleotide synthesis, amino acid metabolism, antioxidant reduced nicotinamide adenine dinucleotide phosphate production and epigenetic methylation processes. Previous studies have reported that the hyper-activation of mitochondrial one-carbon metabolism serves a significant role in malignant cancer phenotypes. A total of 103 patients underwent surgical resection of pancreatic ductal adenocarcinomas (PDAC) at Osaka University Hospital between April 2007 and December 2013 and were enrolled in this study. Subsequently, the expression of the one-carbon metabolic enzymes methylenetetrahydrofolate dehydrogenase 2 (MTHFD2), aldehyde dehydrogenase 1 family member L2 (ALDH1L2), and serine hydroxymethyltransferase (SHMT2) was examined using immunohistochemical analysis. The immunohistochemical analyses demonstrated that patients with high expression levels of MTHFD2, ALDH1L2 or SHMT2 had significantly poor overall survival (OS) and disease-free survival (DFS) rates, as compared with patients with low expression levels. Furthermore, multivariate Cox proportional hazards analysis indicated that MTHFD2 and ALDH1L2 were independent prognostic factors for OS and DFS, whereas SHMT2 was not predictive of DFS. However, high and low expression levels of all three folate metabolic enzymes were significantly associated with improved OS and DFS, compared with the high expression of one or two folate metabolic enzymes. The expression levels of mitochondrial one-carbon metabolic enzymes are independent prognostic factors and potential therapeutic targets for future pancreatic cancer treatments. [ABSTRACT FROM AUTHOR]

[Display omitted] • The germline variants analysis from alcohol metabolism pathway genes obtained a significant variant in the ALDH1L2 gene (rs199841702) found to associate with alcoholic liver disease. • Most of the available online in-silico Pathogenicity prediction tools predicted ALDH1L2 (c.337C > G, p.Pro113Ala) gene variant as 'deleterious' and 'pathogenic'. • The presence of the GC genotype in ALDH1L2 (rs19984170)polymorphism may indicate an increased risk of developing ALD. The pathogenetic events of liver disease are seemingly determined by factors linked to ethanol metabolism. The variations in genes encoding enzymes of the ethanol metabolic pathway can influence exposure to alcohol and thus may act as risk factors for the development of liver disease. The present study aimed to understand the genetic aspect of germline variations in ethanol metabolic pathway genes in two major categories of liver disease i.e. ALD and NAFLD. Targeted Re-sequencing was performed in the two disease categories along with healthy control followed by an assessment and evaluation of the variants in a case vs control manner. The pathogenicity prediction was evaluated using SIFT, PolyPhen, PROVEN, LRT, CADD, FATHMM, EIGEN, REVEL and VarSome, while MD simulation of a novel significant variant was performed using the GROMACS 5.1.4 package. The annotation of targeted re-sequencing results revealed 2172 variants in different locations of the genes. Upon recurrent assessment predominantly focusing on exonic missense variants from these genes of the alcohol metabolism pathway, the ALDH1L2 [c.337C > G, p.Pro113Ala, (rs199841702)] variant was found highly significant with comprehensive results. The amino acid substitution tool that predicted protein stability due to a point mutation showed a decrease in stability. The genotyping distribution of the identified novel variant in the population revealed that heterozygosity is significantly distributed in ALD patients. However, the predominant association between the inherited variant and the cause of developing disease needs further robust study. [ABSTRACT FROM AUTHOR]

Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes—aldehyde dehydrogenase 1 family member 2 (ALDH1L2)—produces NADPH by catabolizing 10-formyl-THF into CO 2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling. [Display omitted] • Loss of ALDH1L2 increases formate and formyl-methionine production • ALDH1L2 levels influence migration in a formyl-peptide receptor-dependent manner • In the primary tumor, ALDH1L2 levels impact metastatic capacity Hennequart et al. describe the role of ALDH1L2, a mitochondrial enzyme involved in one-carbon metabolism, in breast cancer cells. Loss of ALDH1L2 leads to increased production of formate and formyl-methionine, promoting an increase in migration that is dependent on the formyl-peptide receptor and enhancing metastasis in vivo. [ABSTRACT FROM AUTHOR]

Abstract: 10-Formyltetrahydrofolate dehydrogenase (FDH, ALDH1L1), an abundant cytosolic enzyme of folate metabolism, shares significant sequence similarity with enzymes of the aldehyde dehydrogenase (ALDH) family. The enzyme converts 10-formyltetrahydrofolate (10-fTHF) to tetrahydrofolate and CO2 in an NADP+-dependent manner. The mechanism of this reaction includes three consecutive steps with the final occurring in an ALDH-homologous domain. We have recently identified a mitochondrial isoform of FDH (mtFDH), which is the product of a separate gene, ALDH1L2. Its overall identity to cytosolic FDH is about 74%, and the identity between the ALDH domains rises up to 79%. In the present study, human mtFDH was expressed in Escherichia coli, purified to homogeneity, and characterized. While the recombinant enzyme was capable of catalyzing the 10-fTHF hydrolase reaction, it did not produce detectable levels of ALDH activity. Despite the lack of typical ALDH catalysis, mtFDH was able to perform the characteristic 10-fTHF dehydrogenase reaction after reactivation by recombinant 4′-phosphopantetheinyl transferase (PPT) in the presence of coenzyme A. Using site-directed mutagenesis, it was determined that PPT modifies mtFDH specifically at Ser375. The C-terminal domain of mtFDH (residues 413–923) was also expressed in E. coli and characterized. This domain was found to exist as a tetramer and to catalyze an esterase reaction that is typical of other ALDH enzymes. Taken together, our studies suggest that ALDH1L2 has enzymatic properties similar to its cytosolic counterpart, although the inability to catalyze the ALDH reaction with short-chain aldehyde substrates remains an unresolved issue at present. [Copyright &y& Elsevier]