Fatty Acid 2-hydroxylase Research Articles

Long-term estrogen-deprived estrogen receptor α-positive breast cancer cell migration assisted by fatty acid 2-hydroxylase.

The risk of breast cancer (BC) recurrence is high in postmenopausal women, though the underlying molecular mechanisms are not yet fully understood. We developed a long-term estrogen-deprived (LTED) cell line from MCF-7 cells, which we used as an in vitro model for aromatase inhibitor (AI)-resistant estrogen receptor α (ERα)-positive postmenopausal BC. We also describe the involvement of fatty acid 2-hydroxylase (FA2H) in the modulation of LTED cell migration. Small interfering RNA specific to FA2H (siFA2H) could reduce cell migration, whereas the introduction of plasmid expressing FA2H, but not its inactive mutant, resulted in enhanced migration. Moreover, proliferation of the LTED cells was not affected by modulation of FA2H expression. Fulvestrant (FUL), a selective estrogen receptor degrader used to treat AI-resistant ERα-positive postmenopausal BC, was found to induce degradation of ERα together with a decrease in ER-mediated transcription; however, FA2H protein expression and migration remained unchanged. Overall, the findings of this study suggest that FA2H is one of the drivers of LTED cell migration, and that LTED cells resistant to FUL therapy may be involved in malignancy and metastatic mechanisms.

2-Hydroxylation is a chemical switch linking fatty acids to glucose-stimulated insulin secretion

Glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells is metabolically regulated and progressively diminished during the development of type 2 diabetes (T2D). This dynamic process is tightly coupled with fatty acid metabolism, but the underlying mechanisms remain poorly understood. Fatty acid 2-hydroxylase (FA2H) catalyzes the conversion of fatty acids to chiral specific (R)-2-hydroxy fatty acids ((R)-2-OHFAs), which influences cell metabolism. However, little is known about its potential coupling with GSIS in pancreatic β cells. Here, we showed that Fa2h knockout decreases plasma membrane localization and protein level of glucose transporter 2 (GLUT2), which is essential for GSIS, thereby controlling blood glucose homeostasis. Conversely, FA2H overexpression increases GLUT2 on the plasma membrane and enhances GSIS. Mechanistically, FA2H suppresses the internalization and trafficking of GLUT2 to the lysosomes for degradation. Overexpression of wild-type FA2H, but not its mutant with impaired hydroxylase activity in the pancreatic β-cells, improves glucose tolerance by promoting insulin secretion. Levels of 2-OHFAs and Fa2h gene expression are lower in high-fat diet-induced obese mouse islets with impaired GSIS. Moreover, lower gene expression of FA2H is observed in a set of human T2D islets when the insulin secretion index is significantly suppressed, indicating the potential involvement of FA2H in regulating mouse and human GSIS. Collectively, our results identified an FA chemical switch to maintain the proper response of GSIS in pancreatic β cells and provided a new perspective on the β-cell failure that triggers T2D.

FA2H controls cool temperature sensing through modifying membrane sphingolipids in Drosophila

Animals have evolved the ability to detect ambient temperatures, allowing them to search for optimal living environments. In search of the molecules responsible for cold-sensing, we examined a Gal4 insertion line inthe larvae of Drosophila melanogaster from previous screening work, which has a specific expression pattern in the cooling cells (CCs). We identified that the targeted gene, fa2h, which encodes a fatty acid 2-hydroxylase, plays an important role in cool temperature sensing. We found that fa2h mutants exhibit defects in cool avoidance behavior and that this phenotype could be rescued by genetically re-introducing the wild-type version of FA2H in CCs but not the enzymatically disabled point mutation version. Calcium imaging data showed that CCs require fa2h to respond to cool temperature. Lipidomic analysis revealed that the 2-hydroxy sphingolipids content in the cell membranes diminished in fa2h mutants, resulting in increased fluidity of CC neuron membranes. Furthermore, in mammalian systems, we showed that FA2H strongly regulates the function of the TRPV4 channel in response to its agonist treatment and warming. Taken together, our study has uncovered a novel role of FA2H in temperature sensing and has provided new insights into the link between membrane lipid composition and the function of temperature-sensing ion channels.

The fatty acid 2-hydroxylase CsSCS7 is a key hyphal growth factor and potential control target in Colletotrichum siamense.

SCS7 is a fatty acid 2-hydroxylase required for the synthesis of inositol phosphorylceramide but is not essential for normal growth in Saccharomyces cerevisiae. Here, we demonstrate that the Colletotrichum siamense SCS7 homolog CsSCS7 plays a key role in hyphal growth. The CsSCS7 deletion mutant showed strong hyphal growth inhibition, small conidia, and marginally reduced sporulation and also resulted in a sharp reduction in the full virulence and increasing the fungicide sensitivity. The three protein domains (a cytochrome b5 domain, a transmembrane domain, and a hydroxylase domain) are important to CsSCS7 protein function in hyphal growth. The fatty acid assay results revealed that the CsSCS7 gene is important for balancing the contents of multiple mid-long- and short-chain fatty acids. Additionally, the retarded growth and virulence of C. siamense ΔCsSCS7 can be recovered partly by the reintroduction of homologous sequences from Magnaporthe oryzae and Fusarium graminearum but not SCS7 of S. cerevisiae. In addition, the spraying of C. siamense with naked CsSCS7-double-stranded RNA (dsRNAs), which leads to RNAi, increases the inhibition of hyphal growth and slightly decreases disease lesions. Then, we used nano material Mg-Al-layered double hydroxide as carriers to deliver dsRNA, which significantly enhanced the control effect of dsRNA, and the lesion area was obviously reduced. These data indicated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.IMPORTANCECsSCS7, which is homologous to yeast fatty acid 2-hydroxylase SCS7, was confirmed to play a key role in the hyphal growth of Colletotrichum siamense and affect its virulence. The CsSCS7 gene is involved in the synthesis and metabolism of fatty acids. Homologs from the filamentous fungi Magnaporthe oryzae and Fusarium graminearum can recover the retarded growth and virulence of C. siamense ΔCsSCS7. The spraying of double-stranded RNAs targeting CsSCS7 can inhibit hyphal growth and reduce the disease lesion area to some extent. After using nano material Mg-Al layered double hydroxide as carrier, the inhibition rates were significantly increased. We demonstrated that CsSCS7 is an important factor for hyphal growth and affects virulence and may be a potential control target in C. siamense and even in filamentous plant pathogenic fungi.

Key genes of inflammation and Crohn’s disease severity identified via bioinformatics and clinical specimen analysis

Crohn’s disease (CD) is a nonspecific inflammatory disease of digestive tract with limited known biomarkers. We aimed to identify potential molecules involved in CD severity. Weighted gene co-expression network and differentially expressed gene analyses were used to explore hub genes associated with inflammation and involved in pathological processes of CD in the GSE83448 cohort. The expression and relationship of genes with clinical characteristics in normal and CD intestinal mucosa were validated in GSE208303 and our research cohorts. Five genes related to disease and inflammation were identified in the clinically significant modules that were differentially expressed in healthy controls and CD patients. Among them, solute carrier family 39 member 5 (SLC39A5) expression was reduced in CD tissues compared with that in normal tissues; low SLC39A5 expression was associated with CD-simplifying endoscopic score and stenosis. Furthermore, we broadened the bioinformatic threshold with qRT-PCR verification and western blot, and found that the expressions of cytochrome P450 family 2 subfamily S member 1 (CYP2S1), fatty acid 2-hydroxylase (FA2H), fatty acid binding protein 1 (FABP1), and Rho family GTPase 3 (RND3) were reduced in CD tissues. Therefore, SLC39A5, CYP2S1, FA2H, FABP1, and RND3 may be novel biomarkers for CD and associated with severity. Highlights SLC39A5 expression was reduced in CD tissues. Low SLC39A5 expression was associated with CD-simplifying endoscopic score and stenosis. CYP2S1, FA2H, FABP1, and RND3 were reduced in CD tissues.

Novel variant in Moroccan patient with hereditary spastic paraplegia type 35

Hereditary Spastic Paraplegia Type 35 (HSP35) is a complex form of Hereditary Spastic Paraplegia. The main features of HSP35 include progressive paraparesis, dysarthria, and mild cognitive decline, along with the presence of leukodystrphy on brain imaging. HSP35 is caused by pathogenic variants in the fatty acid 2-hydroxylase protein (FA2H).In this study, whole exome sequencing (WES) was performed on a Moroccan family displaying HSP features. The genetic analysis revealed the novel variant (p.Thr352Pro) in the FA2H in the HSP in the family affected by HSP35. Computational analysis demonstrated a reduction in protein stability and alterations in amino acid interactions in the FA2H protein associated with p.Thr352Pro variant. Our study provides more insight about HSP35 associated variants, which can be valuable for counseling patients with HSP. Additionally molecular biology studies are required to investigate the genotype-phenotype correlation of FA2H- associated HSPs.

Spastic ataxic phenotype of Fatty acid 2-hydroxylase associated neurodegeneration: a case series from India

Spastic ataxic phenotype of Fatty acid 2-hydroxylase associated neurodegeneration: a case series from India

The first reports of FA2H-associated neurodegeneration from two unrelated Iranian families.

NBIA (neurodegeneration with brain iron accumulation) is a diverse collection of neurodegenerative illnesses defined by iron accumulation in the basal ganglia. The fatty acid hydroxylase-associated neurodegeneration, or FAHN, is one of the uncommon subtypes of NBIAs, associated with inherited autosomal recessive mutations in gene coding the membrane-bound fatty acid 2 hydroxylase (FA2H) enzyme. Here, we report two cases with FAHN from two unrelated families from Iran confirmed by whole exome sequencing. FAHN is an uncommon variant of NBIA that may manifest as spastic paraparesis without signs of iron buildup on brain imaging. As a result, it should be taken into account while making a differential diagnosis of the hereditary spastic paraplegia (HSP) syndrome, especially in individuals who lack iron deposits.

Fatty Acid 2-Hydroxylase and 2-Hydroxylated Sphingolipids: Metabolism and Function in Health and Diseases.

Sphingolipids containing acyl residues that are hydroxylated at C-2 are found in most, if not all, eukaryotes and certain bacteria. 2-hydroxylated sphingolipids are present in many organs and cell types, though they are especially abundant in myelin and skin. The enzyme fatty acid 2-hydroxylase (FA2H) is involved in the synthesis of many but not all 2-hydroxylated sphingolipids. Deficiency in FA2H causes a neurodegenerative disease known as hereditary spastic paraplegia 35 (HSP35/SPG35) or fatty acid hydroxylase-associated neurodegeneration (FAHN). FA2H likely also plays a role in other diseases. A low expression level of FA2H correlates with a poor prognosis in many cancers. This review presents an updated overview of the metabolism and function of 2-hydroxylated sphingolipids and the FA2H enzyme under physiological conditions and in diseases.

Auranofin ameliorates psoriasis-like dermatitis in an imiquimod-induced mouse by inhibiting of inflammation and upregulating FA2H expression

Psoriasis vulgaris (PV) is a common inflammatory skin disorder with immune imbalance contributing to its pathology. It has been reported that auranofin, a known anti-rheumatic drug, has the therapeutic effects on inflammatory diseases. However, the effects and underlying mechanisms of auranofin on PV have not been reported. Here, we showed that auranofin significantly attenuated the mixture of five proinflammatory cytokines (termed as M5) induced hyperproliferation and inflammation in HaCaT cells, a kind of human immortalized keratinocyte cell line. Topical administration of auranofin markedly alleviated the imiquimod (IMQ)-induced mouse psoriatic dermatitis both in appearance and in pathology. The psoriasis area and severity index (PASI) score, acanthosis, dermal infiltrated inflammatory cells and Ki-67 expression were improved obviously. The results of RNA-sequencing from both M5-induced HaCaT cells and IMQ-treated mouse dermatitis showed that auranofin could regulate inflammation-related signaling pathway. Meanwhile, we observed that fatty acid 2-hydroxylase (FA2H), a key molecule in lipid metabolism, was significantly increased after auraonfin treatment in both M5-induced HaCaT cells and IMQ-treated mouse skin. Knockdown of FA2H in HaCaT cells remarkably inhibited cell apoptosis, increased cell proliferation and the expression profiles of inflammatory-related genes, whereas FA2H overexpression had opposite effect. In conclusion, auranofin notably alleviated IMQ-induced psoriasis-like skin inflammation, which might be mediated by increasing FA2H expression, suggesting its potential to be a novel strategy for psoriasis treatment.

Identification and characterization of noncoding RNAs-associated competing endogenous RNA networks in major depressive disorder.

Major depressive disorder (MDD) is a common and serious mental illness. Many novel genes in MDD have been characterized by high-throughput methods such as microarrays or sequencing. Recently, noncoding RNAs (ncRNAs) were suggested to be involved in the complicated environmental-genetic regulatory network of MDD occurrence; however, the interplay among RNA species, including protein-coding RNAs and ncRNAs, in MDD remains unclear. To investigate the RNA expression datasets downloaded from a public database and construct a network based on differentially expressed long noncoding RNA (lncRNAs), microRNAs (miRNAs), and mRNAs between MDD and controls. Gene expression data were searched in NCBI Gene Expression Omnibus using the search term "major depressive disorder." Six array datasets from humans were related to the search term: GSE19738, GSE32280, GSE38206, GSE52790, GSE76826, and GSE81152. These datasets were processed for initial assessment and subjected to quality control and differential expression analysis. Differentially expressed lncRNAs, miRNAs, and mRNAs were determined, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed, and protein-protein interaction network was generated. The results were analyzed for their association with MDD. After analysis, 3 miRNAs, 12 lncRNAs, and 33 mRNAs were identified in the competing endogenous RNA network. Two of these miRNAs were earlier shown to be involved in psychiatric disorders, and differentially expressed mRNAs were found to be highly enriched in pathways related to neurogenesis and neuroplasticity as per Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. The expression of hub gene fatty acid 2-hydroxylase was enriched, and the encoded protein was found to be involved in myelin formation, indicating that neurological development and signal transduction are involved in MDD pathogenesis. The present study presents candidate ncRNAs involved in the neurogenesis and neuroplasticity pathways related to MDD.

KRTA6A and FA2H Are Hub Genes Associated With Cgas-STING-related Immunogenic Cell Death in Lung Adenocarcinoma.

The immunogenic cell death (ICD) pathway plays a crucial prognostic role in lung adenocarcinoma (LUAD) therapy. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is an upstream mechanism that drives ICD activation, but the interaction of hub genes remains unclear. The present study aimed to investigate the hub genes involved in ICD and the cGAS-STING pathway. The prognostic performance for hub genes and related Gene Ontology (GO) terms were also investigated. Gene expression data of ICD induction and cGAS-STING pathway activation samples were extracted from the Gene Expression Omnibus (GEO) database, and gene expression as well as clinical data of LUAD patients who received pharmaceutical therapy were extracted from The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) were identified, and protein-protein interaction (PPI) analysis was used to identify hub genes. Hazard risk (HR) scores were identified using Kaplan-Meier (K-M) and COX analyses. Gene set enrichment analysis (GSEA) was performed to identify the related GO terms, and receiver operating characteristic (ROC) analysis was used to evaluate the prognosis performance of the related gene sets. A total of 22 DEGs were identified in the two GEO datasets, and six hub genes were identified by PPI analysis. Keratin 6A (KRTA6A) and fatty acid 2-hydroxylase (FA2H) were selected as the hub genes after survival analysis. GSEA and ROC analysis indicated that there was no difference between the KRTA6A and FA2H gene sets on prognosis performance. KRTA6A and FA2H are hub genes associated with the induction of cGAS-STING-related ICD in LUAD.

A new model for fatty acid hydroxylase-associated neurodegeneration reveals mitochondrial and autophagy abnormalities.

Fatty acid hydroxylase-associated neurodegeneration (FAHN) is a rare disease that exhibits brain modifications and motor dysfunctions in early childhood. The condition is caused by a homozygous or compound heterozygous mutation in fatty acid 2 hydroxylase (FA2H), whose encoded protein synthesizes 2-hydroxysphingolipids and 2-hydroxyglycosphingolipids and is therefore involved in sphingolipid metabolism. A few FAHN model organisms have already been established and give the first insight into symptomatic effects. However, they fail to establish the underlying cellular mechanism of FAHN so far. Drosophila is an excellent model for many neurodegenerative disorders; hence, here, we have characterized and validated the first FAHN Drosophila model. The investigation of loss of dfa2h lines revealed behavioral abnormalities, including motor impairment and flying disability, in addition to a shortened lifespan. Furthermore, alterations in mitochondrial dynamics, and autophagy were identified. Analyses of patient-derived fibroblasts, and rescue experiments with human FA2H, indicated that these defects are evolutionarily conserved. We thus present a FAHN Drosophila model organism that provides new insights into the cellular mechanism of FAHN.

Hydrogen Peroxide Enhances Fatty Acid 2-Hydroxylase Expression to Impede the Lipopolysaccharides-Triggered Apoptosis of Human Mesenchymal Stem Cells

As a type of stem cells that mainly exist in the connective tissue or interstitium, mesenchymal stem cells (MSCs) exhibit great potential in self-renewal and multi-directional differentiation. They have been clinically utilized for the treatment of various diseases including cancer. This study aims to provide solid evidence for the further development and application of MSCs in human diseases. MSCs were assigned into 5 groups: control group, LPS group, low-, medium- and high-dose hydrogen peroxide groups. After one-hour treatment with LPS, MSCs were exposed to H 2 O 2 for 12 hours followed by analysis of cell apoptosis, viability via EdU staining, TUNEL assay and flow cytometry, FA2H expression by qPCR and Western blotting. The hydrogen peroxide treatment reduced proportion of apoptotic cells induced by LPS, along with enhanced viability and milder DNA damage. In addition, hydrogen peroxide impeded the LPS-triggered apoptosis of human MSCs. The results above proved that hydrogen peroxide significantly impeded the LPS-triggered apoptosis of MSCs, and further increased cell viability. This protective effect of hydrogen peroxide was mainly achieved by upregulation of FA2H expression. In conclusion, hydrogen peroxide can enhance FA2H expression to impede the LPS-triggered apoptosis of human MSCs. This finding helps to improve the further development and application of MSCs in treating human diseases.

Dysregulated ceramides metabolism by fatty acid 2-hydroxylase exposes a metabolic vulnerability to target cancer metastasis

Whereas it is appreciated that cancer cells rewire lipid metabolism to survive and propagate, the roles of lipid metabolism in metastasis remain largely unknown. In this study, using esophageal squamous cell carcinoma (ESCC) as a pulmonary metastasis model, we find that the enzyme fatty acid 2-hydroxylase (FA2H), which catalyzes the hydroxylation of free fatty acids (FAs), is enriched in a subpopulation of ESCC cells with high metastatic potential, and that FA2H knockdown markedly mitigates metastatic lesions. Moreover, increased FA2H expression is positively associated with poor survival in patients with ESCC. Lipidomics analysis identifies that two dihydroceramides—Cer(d18:0/24:0) and Cer(d18:0/24:1)—are increased in FA2H-depleted metastasizing ESCC cells. Upon administration, Cer(d18:0/24:0) and Cer(d18:0/24:1) impair the formation of overt metastases in a mouse experimental metastasis model. Then, forkhead box protein C2 (FOXC2) and FA2H are found to be co-upregulated in metastatic ESCC cell populations and ESCC specimens, and FA2H expression is further experimentally verified to be transcriptionally induced by FOXC2, which is boosted per se by tumour necrosis factor α (TNFα), a critical pro-metastasis cytokine in the tumour microenvironment, in metastasizing cells. Together, these results demonstrate that TNFα-FOXC2-FA2H is a novel signaling axis to promote metastasis, and its downstream dihydroceramide products could be promising drugs to intervene in metastasis.

Association of Early Clinical Response to Laser Rejuvenation of Photoaged Skin with Increased Lipid Metabolism and Restoration of Skin Barrier Function

Laser resurfacing treatments for photoaged skin have improved dramatically over the past decades, but few studies have examined the molecular mechanisms underlying differences in clinical response. Seventeen white female participants with moderate-to-severe photoaging received nonablative fractional laser treatment on the face and forearm once monthly for 6 months. Biopsies for microarray analysis were performed at baseline and 7 days after facial treatment and at baseline and 1, 7, 14, and 29 days after forearm treatment in each participant, resulting in 119 total samples. Participants were stratified into fast (n= 11) and slow (n= 6) responders on the basis of the presence of clinical improvement after the first treatment. Microarray analysis revealed the upregulation of genes associated with matrix metalloproteinases, collagen and extracellular components, TGF-β signaling, double-stranded RNA signaling, and retinoic acid synthesis after treatment that did not differ significantly between fast and slow responders. Cluster and enrichment analyses suggested significantly greater activation of lipid metabolism and keratinocyte differentiation in fast responders, who showed greater upregulation of acyltransferases, fatty acid elongases, fatty acid 2-hydroxylase, fatty acid desaturases, and specific keratins that may contribute to epidermal barrier function. These results create, to our knowledge, a previously unreported atlas of molecular changes that correlate with improvements in photoaging after laser therapy.

Age-Dependent Increase in Schmidt-Lanterman Incisures and a Cadm4-Associated Membrane Skeletal Complex in Fatty Acid 2-hydroxylase Deficient Mice: a Mouse Model of Spastic Paraplegia SPG35

PNS and CNS myelin contain large amounts of galactocerebroside and sulfatide with 2-hydroxylated fatty acids. The underlying hydroxylation reaction is catalyzed by fatty acid 2-hydroxylase (FA2H). Deficiency in this enzyme causes a complicated hereditary spastic paraplegia, SPG35, which is associated with leukodystrophy. Mass spectrometry-based proteomics of purified myelin isolated from sciatic nerves of Fa2h-deficient (Fa2h−/−) mice revealed an increase in the concentration of the three proteins Cadm4, Mpp6 (Pals2), and protein band 4.1G (Epb41l2) in 17-month-old, but not in young (4 to 6-month-old), Fa2h−/− mice. These proteins are known to form a complex, together with the protein Lin7, in Schmidt-Lanterman incisures (SLIs). Accordingly, the number of SLIs was significantly increased in 17-month-old but not 4-month-old Fa2h−/− mice compared to age-matched wild-type mice. On the other hand, the relative increase in the SLI frequency was less pronounced than expected from Cadm4, Lin7, Mpp6 (Pals2), and band 4.1G (Epb41l2) protein levels. This suggests that the latter not only reflect the higher SLI frequency but that the concentration of the Cadm4 containing complex itself is increased in the SLIs or compact myelin of Fa2h−/− mice and may potentially play a role in the pathogenesis of the disease. The proteome data are available via ProteomeXchange with identifier PXD030244.

Identification of novel mutations by targeted next-generation sequencing in Moroccan families clinically diagnosed with a neuromuscular disorder

The identification of underlying genes of genetic conditions has expanded greatly in the past decades, which has broadened the field of genes responsible for inherited neuromuscular diseases. We aimed to investigate mutations associated with neuromuscular disorders phenotypes in 2 Moroccan families. Next-generation sequencing combined with Sanger sequencing could assist with understanding the hereditary variety and underlying disease mechanisms in these disorders. Two novel homozygous mutations were described in this study. The SIL1 mutation is the first identified in the Moroccan population, the mutation was identified as the main cause of Marinesco-Sjogren syndrome in one patient. While the second mutation identified in the fatty acid 2-hydroxylase gene (FA2H) was associated with the Spastic paraplegia 35 in another patient, both transmitted in an autosomal recessive pattern. These conditions are extremely rare in the North African population and may be underdiagnosed due to overlapping clinical characteristics and heterogeneity of these diseases. We have reported in this studymutations associated with the diseases found in the patients. In addition, we have narrowed the phenotypic spectrum, as well as the diagnostic orientation of patients with neuromuscular disorders, who might have very similar symptoms to other disease groups.Keywords: Neuromuscular Disorders; Next-Generation Sequencing; Hereditary Spastic Paraplegia Type 35; North Africa; Marinesco-Sjogren syndrome.

Circular Network of Coregulated Sphingolipids Dictates Chronic Hypoxia Damage in Patients With Tetralogy of Fallot.

Background: Tetralogy of Fallot (TOF) is the most common cyanotic heart disease. However, the association of cardiac metabolic reprogramming changes and underlying molecular mechanisms in TOF-related chronic myocardial hypoxia damage are still unclear.Methods: In this study, we combined microarray transcriptomics analysis with liquid chromatography tandem-mass spectrometry (LC–MS/MS) spectrum metabolomics analysis to establish the metabolic reprogramming that occurs in response to chronic hypoxia damage. Two Gene Expression Omnibus (GEO) datasets, GSE132176 and GSE141955, were downloaded to analyze the metabolic pathway in TOF. Then, a metabolomics analysis of the clinical samples (right atrial tissue and plasma) was performed. Additionally, an association analysis between differential metabolites and clinical phenotypes was performed. Next, four key genes related to sphingomyelin metabolism were screened and their expression was validated by real-time quantitative PCR (QT-PCR).Results: The gene set enrichment analysis (GSEA) showed that sphingolipid metabolism was downregulated in TOF and the metabolomics analysis showed that multiple sphingolipids were dysregulated. Additionally, genes related to sphingomyelin metabolism were identified. We found that four core genes, UDP-Glucose Ceramide Glucosyltransferase (UGCG), Sphingosine-1-Phosphate Phosphatase 2 (SGPP2), Fatty Acid 2-Hydroxylase (FA2H), and Sphingosine-1-Phosphate Phosphatase 1 (SGPP1), were downregulated in TOF.Conclusion: Sphingolipid metabolism was downregulated in TOF; however, the detailed mechanism needs further investigation.

Perfluorooctanoic acid (PFOA) as a stimulator of estrogen receptor-negative breast cancer MDA-MB-231 cell aggressiveness: Evidence for involvement of fatty acid 2-hydroxylase (FA2H) in the stimulated cell migration.

Detailed in vitro studies on the effects of perfluorooctanoic acid (PFOA) have demonstrated that activation of peroxisome proliferator-activated receptor α (PPARα) is a key process by which PFOA affects the malignancy of estrogen receptor α (ERα)-positive breast cancer cells. However, there is very little information on the PPARα-regulated genes responsible for the effects of PFOA in ERα-negative breast cancer cell malignancy. We recently demonstrated that fatty acid 2-hydroxylase (FA2H) stimulates the migration of ERα-negative human MDA-MB-231 cells, and PPARα is a key factor for the induction of FA2H in these cells. However, evidence for the relationship between PFOA exposure and PPARα-FA2H axis-driven migration has not been obtained. Here we analyzed the effects of PFOA on PPARα transcription and FA2H expression in relation to MDA-MB-231 cell migration. We found that simultaneously with stimulated migration, PFOA upregulated FA2H and activated the transcription of PPARα. FA2H-selective siRNA, but not siRNA control, clearly dampened PFOA-mediated cell migration. There is an inhibitory interaction between PPARα and PPARβ/δ (i.e., PPARβ/δ can suppress PPARα-mediated transcription) in MDA-MB-231 cells, but even in the presence of PPARβ/δ expression, PFOA appeared to free PPARα to upregulate FA2H. Collectively, our findings show that i) PFOA activates PPARα-mediated transcription, ii) PFOA stimulates migration dependent on FA2H expression, and iii) mechanistically, PFOA relieves PPARβ/δ suppression of PPARα activity to upregulate FA2H in MDA-MB-231 cells.