Ablation of Fatty Acid Transport Protein-4 Enhances Cone Survival, M-cone Vision, and Synthesis of Cone-Tropic 9-cis-Retinal in rd12 Mouse Model of Leber Congenital Amaurosis.

The canonical visual cycle employing RPE65 as the retinoid isomerase regenerates 11-cis-retinal to support both rod- and cone-mediated vision. Mutations of RPE65 are associated with Leber congenital amaurosis that results in rod and cone photoreceptor degeneration and vision loss of affected patients at an early age. Dark-reared Rpe65-/- mouse has been known to form isorhodopsin that employs 9-cis-retinal as the photosensitive chromophore. The mechanism regulating 9-cis-retinal synthesis and the role of the endogenous 9-cis-retinal in cone survival and function remain largely unknown. In this study, we found that ablation of fatty acid transport protein-4 (FATP4), a negative regulator of 11-cis-retinol synthesis catalyzed by RPE65, increased the formation of 9-cis-retinal, but not 11-cis-retinal, in a light-independent mechanism in both sexes of RPE65-null rd12 mice. Both rd12 and rd12;Fatp4-/- mice contained a massive amount of all-trans-retinyl esters in the eyes, exhibiting comparable scotopic vision and rod degeneration. However, expression levels of M- and S-opsins as well as numbers of M- and S-cones surviving in the superior retinas of rd12;Fatp4-/ - mice were at least twofold greater than those in age-matched rd12 mice. Moreover, FATP4 deficiency significantly shortened photopic b-wave implicit time, improved M-cone visual function, and substantially deaccelerated the progression of cone degeneration in rd12 mice, whereas FATP4 deficiency in mice with wild-type Rpe65 alleles neither induced 9-cis-retinal formation nor influenced cone survival and function. These results identify FATP4 as a new regulator of synthesis of 9-cis-retinal, which is a "cone-tropic" chromophore supporting cone survival and function in the retinas with defective RPE65.

Expression of Placental Lipid Transporters in Pregnancies Complicated by Gestational and Type 1 Diabetes Mellitus.

The objective of the study was to assess the expression of proteins responsible for placental lipid transport in term pregnancies complicated by well-controlled gestational (GDM) and type 1 diabetes mellitus (PGDM). A total of 80 placental samples were obtained from patients diagnosed with PGDM (n = 20), GDM treated with diet (GDMG1, n = 20), GDM treated with diet and insulin (GDMG2, n = 20), and a non-diabetic control group (n = 20). Umbilical and uterine artery blood flows were assessed by means of ultrasound in the period prior to delivery and computer-assisted quantitative morphometry of immunostained placental sections was performed to determine the expression of selected proteins. The morphometric analysis performed for the vascular density-matched placental samples demonstrated a significant increase in the expression of fatty acid translocase (CD36), fatty acid binding proteins (FABP1, FABP4 and FABP5), as well as a decrease in the expression of endothelial lipase (EL) and fatty acid transport protein (FATP4) in the PGDM-complicated pregnancies as compared to the GDMG1 and control groups (p < 0.05). No significant differences with regard to the placental expression of lipoprotein lipase (LPL) and FATP6 protein between GDM/PGDM and non-diabetic patients were noted. Maternal pre-pregnancy weight, body mass index, placental weight as well as the expression of LPL and FABP4 were selected by the linear regression model as the strongest contributors to the fetal birth weight. To conclude, in placentas derived from pregnancies complicated by well-controlled PGDM, the expression of several lipid transporters, including EL, CD36, FATP4, FABP1, FABP4 and FABP5, is altered. Nonetheless, only LPL and FABP4 were significant predictors of the fetal birth weight.

Degradation of FATTY ACID EXPORT PROTEIN1 by RHOMBOID-LIKE PROTEASE11 contributes to cold tolerance in Arabidopsis.

Plants need to acclimate to different stresses to optimize growth under unfavorable conditions. In Arabidopsis (Arabidopsis thaliana), the abundance of the chloroplast envelope protein FATTY ACID EXPORT PROTEIN1 (FAX1) decreases after the onset of low temperatures. However, how FAX1 degradation occurs and whether altered FAX1 abundance contributes to cold tolerance in plants remains unclear. The rapid cold-induced increase in RHOMBOID-LIKE PROTEASE11 (RBL11) transcript levels, the physical interaction of RBL11 with FAX1, the specific FAX1 degradation after RBL11 expression, and the absence of cold-induced FAX1 degradation in rbl11 loss-of-function mutants suggest that this enzyme is responsible for FAX1 degradation. Proteomic analyses showed that rbl11 mutants have higher levels of FAX1 and other proteins involved in membrane lipid homeostasis, suggesting that RBL11 is a key element in the remodeling of membrane properties during cold conditions. Consequently, in the cold, rbl11 mutants show a shift in lipid biosynthesis toward the eukaryotic pathway, which coincides with impaired cold tolerance. To test whether cold sensitivity is due to increased FAX1 levels, we analyzed FAX1 overexpressors. The rbl11 mutants and FAX1 overexpressor lines show superimposable phenotypic defects upon exposure to cold temperatures. Our re-sults show that the cold-induced degradation of FAX1 by RBL11 is critical for Arabidop-sis to survive cold and freezing periods.

AI-Based Homology Modelling of Fatty Acid Transport Protein 1 Using AlphaFold: Structural Elucidation and Molecular Dynamics Exploration.

Fatty acid transport protein 1 (FATP1) is an integral transmembrane protein that is involved in facilitating the translocation of long-chain fatty acids (LCFA) across the plasma membrane, thereby orchestrating the importation of LCFA into the cell. FATP1 also functions as an acyl-CoA ligase, catalyzing the ATP-dependent formation of fatty acyl-CoA using LCFA and VLCFA (very-long-chain fatty acids) as substrates. It is expressed in various types of tissues and is involved in the regulation of crucial signalling pathways, thus playing a vital role in numerous physiological and pathological conditions. Structural insight about FATP1 is, thus, extremely important for understanding the mechanism of action of this protein and developing efficient treatments against its anomalous expression and dysregulation, which are often associated with pathological conditions such as breast cancer. As of now, there has been no prior prediction or evaluation of the 3D configuration of the human FATP1 protein, hindering a comprehensive understanding of the distinct functional roles of its individual domains. In our pursuit to unravel the structure of the most commonly expressed isoforms of FATP1, we employed the cutting-edge ALPHAFOLD 2 model for an initial prediction of the entire protein's structure. This prediction was complemented by molecular dynamics simulations, focusing on the most promising model. We predicted the structure of FATP1 in silico and thoroughly refined and validated it using coarse and molecular dynamics in the absence of the complete crystal structure. Their relative dynamics revealed the different properties of the characteristic FATP1.

Deep sequencing of circulating miRNAs and target mRNAs level in deep venous thrombosis patients.

Deep venous thrombosis is one of the most common peripheral vascular diseases that lead to major morbidity and mortality. The authors aimed to identify potential differentially expressed miRNAs and target mRNAs, which were helpful in understanding the potential molecule mechanism of deep venous thrombosis. The plasma samples of patients with deep venous thrombosis were obtained for the RNA sequencing. Differentially expressed miRNAs were identified, followed by miRNA-mRNA target analysis. Enrichment analysis was used to analyze the potential biological function of target mRNAs. GSE19151 and GSE173461 datasets were used for expression validation of mRNAs and miRNAs. 131 target mRNAs of 21 differentially expressed miRNAs were identified. Among which, 8 differentially expressed miRNAs including hsa-miR-150-5p, hsa-miR-326, hsa-miR-144-3p, hsa-miR-199a-5p, hsa-miR-199b-5p, hsa-miR-125a-5p, hsa-let-7e-5p and hsa-miR-381-3p and their target mRNAs (PRKCA, SP1, TP53, SLC27A4, PDE1B, EPHB3, IRS1, HIF1A, MTUS1 and ZNF652) were found associated with deep venous thrombosis for the first time. Interestingly, PDE1B and IRS1 had a potential diagnostic value for patients. Additionally, 3 important signaling pathways including p53, PI3K-Akt and MAPK were identified in the enrichment analysis of target mRNAs (TP53, PRKCA and IRS1). Identified circulating miRNAs and target mRNAs and related signaling pathways may be involved in the process of deep venous thrombosis.

Myeloid-specific fatty acid transport protein 4 deficiency induces a sex-dimorphic susceptibility for nonalcoholic steatohepatitis in mice fed a high-fat, high-cholesterol diet.

Newborns with FATP4 mutations exhibit ichthyosis prematurity syndrome (IPS), and adult patients show skin hyperkeratosis, allergies, and eosinophilia. We have previously shown that the polarization of macrophages is altered by FATP4 deficiency; however, the role of myeloid FATP4 in the pathogenesis of nonalcoholic steatohepatitis (NASH) is not known. We herein phenotyped myeloid-specific Fatp4-deficient (Fatp4M-/-) mice under chow and high-fat, high-cholesterol (HFHC) diet. Bone-marrow-derived macrophages (BMDMs) from Fatp4M-/- mice showed significant reduction in cellular sphingolipids in males and females, and additionally phospholipids in females. BMDMs and Kupffer cells from Fatp4M-/- mice exhibited increased LPS-dependent activation of proinflammatory cytokines and transcription factors PPARγ, CEBPα, and p-FoxO1. Correspondingly, these mutants under chow diet displayed thrombocytopenia, splenomegaly, and elevated liver enzymes. After HFHC feeding, Fatp4M-/- mice showed increased MCP-1 expression in livers and subcutaneous fat. Plasma MCP-1, IL4, and IL13 levels were elevated in male and female mutants, and female mutants additionally showed elevation of IL5 and IL6. After HFHC feeding, male mutants showed an increase in hepatic steatosis and inflammation, whereas female mutants showed a greater severity in hepatic fibrosis associated with immune cell infiltration. Thus, myeloid-FATP4 deficiency led to steatotic and inflammatory NASH in males and females, respectively. Our work offers some implications for patients with FATP4 mutations and also highlights considerations in the design of sex-targeted therapies for NASH treatment.NEW & NOTEWORTHY FATP4 deficiency in BMDMs and Kupffer cells led to increased proinflammatory response. Fatp4M-/- mice displayed thrombocytopenia, splenomegaly, and elevated liver enzymes. In response to HFHC feeding, male mutants were prone to hepatic steatosis, whereas female mutants showed exaggerated fibrosis. Our study provides insights into a sex-dimorphic susceptibility to NASH by myeloid-FATP4 deficiency.

Fatty acid transport proteins (FATPs) in cancer.

Lipids play pivotal roles in cancer biology. Lipids have a wide range of biological roles, especially in cell membrane synthesis, serve as energetic molecules in regulating energy-demanding processes; and they play a significant role as signalling molecules and modulators of numerous cellular functions. Lipids may participate in the development of cancer through the fatty acid signalling pathway. Lipids consumed in the diet act as a key source of extracellular pools of fatty acids transported into the cellular system. Increased availability of lipids to cancer cells is due to increased uptake of fatty acids from adipose tissues. Lipids serve as a source of energy for rapidly dividing cancerous cells. Surviving requires the swift synthesis of biomass and membrane matrix to perform exclusive functions such as cell proliferation, growth, invasion, and angiogenesis. FATPs (fatty acid transport proteins) are a group of proteins involved in fatty acid uptake, mainly localized within cells and the cellular membrane, and have a key role in long-chain fatty acid transport. FATPs are composed of six isoforms that are tissue-specific and encoded by a specific gene. Previous studies have reported that FATPs can alter fatty acid metabolism, cell growth, and cell proliferation and are involved in the development of various cancers. They have shown increased expression in most cancers, such as melanoma, breast cancer, prostate cancer, renal cell carcinoma, hepatocellular carcinoma, bladder cancer, and lung cancer. This review introduces a variety of FATP isoforms and summarises their functions and their possible roles in the development of cancer.

Role of fatty acid transport protein 4 in metabolic tissues: insights into obesity and fatty liver disease.

Fatty acid (FA) metabolism is a series of processes that provide structural substances, signalling molecules and energy. Ample evidence has shown that FA uptake is mediated by plasma membrane transporters including FA transport proteins (FATPs), caveolin-1, fatty-acid translocase (FAT)/CD36, and fatty-acid binding proteins. Unlike other FA transporters, the functions of FATPs have been controversial because they contain both motifs of FA transport and fatty acyl-CoA synthetase (ACS). The widely distributed FATP4 is not a direct FA transporter but plays a predominant function as an ACS. FATP4 deficiency causes ichthyosis premature syndrome in mice and humans associated with suppression of polar lipids but an increase in neutral lipids including triglycerides (TGs). Such a shift has been extensively characterized in enterocyte-, hepatocyte-, and adipocyte-specific Fatp4-deficient mice. The mutants under obese and non-obese fatty livers induced by different diets persistently show an increase in blood non-esterified free fatty acids and glycerol indicating the lipolysis of TGs. This review also focuses on FATP4 role on regulatory networks and factors that modulate FATP4 expression in metabolic tissues including intestine, liver, muscle, and adipose tissues. Metabolic disorders especially regarding blood lipids by FATP4 deficiency in different cell types are herein discussed. Our results may be applicable to not only patients with FATP4 mutations but also represent a model of dysregulated lipid homeostasis, thus providing mechanistic insights into obesity and development of fatty liver disease.

Genotype of autosomal recessive congenital ichthyosis from a tertiary care center in India.

BACKGROUND: Autosomal recessive congenital ichthyosis (ARCI) refers to non-syndromic ichthyosis caused by mutations in one of the 13 identified genes. There are limited data on the genotype of ARCI and its phenotypic correlation from India. OBJECTIVES: The aim of this study was to characterize the genotype of ARCI among patients from the Indian subcontinent. METHODS: Twenty-eight patients clinically diagnosed as ARCI were recruited prospectively from September 2017 to June 2019 (21 months). DNA was extracted from peripheral blood and analyzed for the 13 described ARCI genes-TGM1, ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, LIPN, NIPAL4, PNPLA1, SDR9C7, SLC27A4, SULT2B1, and CASP14 by next-generation sequencing using an in-house panel. The variants identified were confirmed by Sanger sequencing and compared with known pathogenic variants to establish pathogenicity. We also attempted to correlate the phenotype with the genotype. RESULTS: Among the 28 patients recruited (M = 17, F = 11), we identified phenotypes of congenital ichthyosiform erythroderma in 12 (42.9%), 8 with lamellar ichthyosis (28.6%), 5 with intermediate phenotype (17.9%), and 3 with bathing suit ichthyosis (10.7%). Pathogenic and likely pathogenic variants were identified in 22 (78.6%) patients, involving 7 out of the 13 known ARCI genes while 6 (21.4%) did not have pathogenic variants. These included TGM1 mutation in 6 (21.4%), ALOX12B and ALOXE3 in 4 (14.3%) each, NIPAL4 and PNPLA1 in 3 (10.7%) each, and ABCA12 and CERS3 in 1 (3.6%) patient each. Previously unknown pathogenic variants were found in 59.1 % of patients. CONCLUSIONS: Our patients with ARCI were found to have genotypes as previously described in other populations.

Solute Carrier Family 27 Member 6 (SLC27A6) Possibly Promotes the Proliferation of Papillary Thyroid Cancer by Regulating c-MYC.

To investigate the expression and mechanism of LSC27A6 in papillary thyroid cancer (PTC). We analyzed the differential expression of SLC27A6 in PTC tissues and normal tissues based on the TCGA database and validated it using immunohistochemistry. Wilcoxon rank sum, chi-square test, or Fisher exact exam were used to analyze the relationship between the expression of SLC27A6 and clinicopathological information. Samples were divided into two groups according to whether BRAF was mutated or not, and Wilcoxon rank sum was used to determine whether the expression of SLC27A6 was related to BRAF mutation. The effects of SLC27A6 on the proliferation, migration, and apoptosis of PTC cells were detected by cell counting kit-8 (CCK8), colony formation assay, transwell assay, and flow cytometry. Spearman correlation analysis was used to evaluate the relationship between SLC27A6 and c-MYC. Protein expression was detected by Western blot. The expression of SLC27A6 was higher in PTC and positively correlated with N stage. SLC27A6 expression was higher in samples with BRAF mutations. Down-regulation of SLC27A6 inhibited cell proliferation, migration, and invasion and induced apoptosis. Spearman correlation analysis showed that SLC27A6 was positively correlated with c-MYC. Knockdown of SLC27A6 inhibited c-MYC expression. Our results suggest that SLC27A6 is overexpressed in PTC tissues and affects the progression of PTC by regulating c-MYC.

Withaferin A Promotes White Adipose Browning and Prevents Obesity Through Sympathetic Nerve-Activated Prdm16-FATP1 Axis.

The increasing prevalence of obesity has resulted in demands for the development of new effective strategies for obesity treatment. Withaferin A (WA) shows a great potential for prevention of obesity by sensitizing leptin signaling in the hypothalamus. However, the mechanism underlying the weight- and adiposity-reducing effects of WA remains to be elucidated. In this study, we report that WA treatment induced white adipose tissue (WAT) browning, elevated energy expenditure, decreased respiratory exchange ratio, and prevented high-fat diet-induced obesity. The sympathetic chemical denervation dampened the WAT browning and also impeded the reduction of adiposity in WA-treated mice. WA markedly upregulated the levels of Prdm16 and FATP1 (Slc27a1) in the inguinal WAT (iWAT), and this was blocked by sympathetic denervation. Prdm16 or FATP1 knockdown in iWAT abrogated the WAT browning-inducing effects of WA and restored the weight gain and adiposity in WA-treated mice. Together, these findings suggest that WA induces WAT browning through the sympathetic nerve-adipose axis, and the adipocytic Prdm16-FATP1 pathway mediates the promotive effects of WA on white adipose browning.

Effects of DHA dietary intervention on hepatic lipid metabolism in apolipoprotein E-deficient and C57BL/6J wild-type mice.

Lipid metabolic disorder occurs when ApoE gene is deficient. However, the role of Docosahexaenoic acid (DHA) in relieving hepatic lipid metabolic disorder in apolipoprotein E-deficient (ApoE -/-) mice remains unknown. We fed 3-month-old C57BL/6J wild-type (C57 wt) and ApoE -/- mice respectively with normal or DHA fortified diet for 5 months. We found ApoE gene deficiency caused hepatic lipid deposition and increased lipid levels in plasma and liver. Hepatic gene expression of SRB1, CD36 and FABP5 in ApoE -/- mice, protein expression of HMGCR, LRP1 in C57 wt mice and protein expression of LRP1 in ApoE -/- mice increased after DHA intervention. In DHA-fed ApoE -/- mice, LXRα/ß and PPARα protein expression down-regulated in cytoplasm, but LXRα/ß protein expression up-regulated in nucleus. DHA treatment decreased RXRα and RXRß expression in C57 wt and ApoE -/- female mice. Deletion of ApoE gene caused lipid metabolism disorder in liver of mice. DHA treatment efficiently meliorated lipid metabolism caused by ApoE deficient through the regulation of gene and protein expressions of molecules involved in liver fatty acids transport and lipid metabolism.

Tetraspanin TM4SF5 in hepatocytes negatively modulates SLC27A transporters during acute fatty acid supply.

Transmembrane 4 L six family member 5 (TM4SF5) is involved in nonalcoholic steatosis and further aggravation of liver disease. However, its mechanism for regulating FA accumulation is unknown. We investigated how TM4SF5 in hepatocytes affected FA accumulation during acute FA supply. TM4SF5-expressing hepatocytes and mouse livers accumulated less FAs, compared with those of TM4SF5 deficiency or inactivation. Binding of TM4SF5 to SLC27A2 increased gradually upon acute FA treatment, whereas TM4SF5 constitutively bound SLC27A5. Suppression of either SLC27A2 or SLC27A5 in hepatocytes expressing TM4SF5 differentially modulated initial and maximal FA uptake levels for a fast turnover of fatty acid. Altogether, TM4SF5 negatively modulates FA accumulation into hepatocytes via association with the transporters for an energy homeostasis, when FA are supplied acutely.

Effects of Simvastatin on Lipid Metabolism in Wild-Type Mice and Mice with Muscle PGC-1α Overexpression.

Previous studies suggest that statins may disturb skeletal muscle lipid metabolism potentially causing lipotoxicity with insulin resistance. We investigated this possibility in wild-type mice (WT) and mice with skeletal muscle PGC-1α overexpression (PGC-1α OE mice). In WT mice, simvastatin had only minor effects on skeletal muscle lipid metabolism but reduced glucose uptake, indicating impaired insulin sensitivity. Muscle PGC-1α overexpression caused lipid droplet accumulation in skeletal muscle with increased expression of the fatty acid transporter CD36, fatty acid binding protein 4, perilipin 5 and CPT1b but without significant impairment of muscle glucose uptake. Simvastatin further increased the lipid droplet accumulation in PGC-1α OE mice and stimulated muscle glucose uptake. In conclusion, the impaired muscle glucose uptake in WT mice treated with simvastatin cannot be explained by lipotoxicity. PGC-1α OE mice are protected from lipotoxicity of fatty acids and triglycerides by increased the expression of FABP4, formation of lipid droplets and increased expression of CPT1b.

Abundance of solute carrier family 27 member 6 (SLC27A6) in the bovine mammary gland alters fatty acid metabolism.

Milk fatty acid (FA) composition is associated with the nutritional value of milk and is known to vary with the stage of lactation. Although biochemical aspects controlling FA metabolism in the bovine mammary gland are well-established, less is known about the underlying molecular mechanisms. Thus, to address some of these shortcomings, the present study sought to evaluate milk FA composition and mammary transcriptome profiles at different stages of lactation. Compared with 90 d of lactation, at 315 d of lactation, there was an increase in the concentrations of C18:2, polyunsaturated fatty acids (PUFA), and short-chain fatty acids (SCFA), and a decrease in C16:0 and long-chain fatty acids (LCFA) in milk. To further identify candidate genes and pathways responsible for these phenotypic differences, the transcriptome of bovine mammary tissue at 90 d (peak) and 315 d (late) of lactation was profiled using RNA-seq. A total of 827 differentially expressed genes were identified. Bioinformatic analysis revealed that the major differentially modulated lipid metabolic pathways were the PPAR signaling pathway, alpha-linolenic acid metabolism and linoleic acid metabolism. Compared with peak lactation, the mammary tissue at late lactation had lower abundance of genes related to FA transport and activation (CD36, SLC27A6, ACSM1, FABP3 and FABP4). Thus, to further explore the role of FA transport into mammary cells, we knocked down fatty acid transport protein 6 (solute carrier family 27 member 6, SLC27A6) in the bovine mammary epithelial cells (BMECs) using siRNA. The knockdown of SLC27A6 dramatically downregulated the mRNA abundance of genes associated with FA activation (ACSL4), oxidation (CPT1A) and transport (CD36), while the abundance of genes associated with transcription regulation (PPARG), diacylglycerol acyltransferase 1 (DGAT1), FA binding (FABP3), and desaturation (FADS2) was upregulated. In addition, SLC27A6 silenced the intracellular content of triglyceride (TG) and the percentage of C18:1cis9 and C20:4cis5,8,11,14 was greater, whereas that of C16:0 and C18:0 was lower. Overall, in vivo results indicated that LCFA transport into mammary cells during late lactation partly explains the difference in the FA profiles. In vitro analyses underscored how FA transport via SLC27A6 could dictate in part the intracellular utilization of FA for TG synthesis versus oxidation. The data provide strong support for a central role of SLC27A6 in the regulation of FA metabolism in BMECs.

Profiling the expression of fatty acid-binding proteins and fatty acid transporters in mouse microglia and assessing their role in docosahexaenoic acid-d5 uptake.

While the processes governing docosahexaenoic acid (DHA) trafficking across the blood-brain barrier have been elucidated, factors governing DHA uptake into microglia, an essential step for this fatty acid to exert its anti-inflammatory effects, are unknown. This study assessed the mRNA and protein expression of fatty acid-binding proteins (FABPs) and fatty acid transport proteins (FATPs) in mouse BV-2 cells and their mRNA expression in primary mouse microglia. The microglial uptake of DHA-d5, a surrogate of DHA, was assessed by LC-MS/MS following interventions including temperature reduction, silencing of various FABP isoforms, competition with DHA, and metabolic inhibition. It was found that DHA-d5 uptake at 4°C was 39.6% lower than at 37°C, suggesting that microglial uptake of DHA-d5 likely involves passive and/or active uptake mechanisms. Of all FABP and FATP isoforms probed, only FABP3, FABP4, FABP5, FATP1, and FATP4 were expressed at both the mRNA and protein level. Silencing of FABP3, FABP4, and FABP5 resulted in no change in cellular DHA-d5 uptake, nor did concomitant DHA administration or the presence of 0.1% sodium azide/50 mM 2-deoxy-D-glucose. This study is the first to identify the presence of FABPs and FATPs in mouse microglia, albeit these proteins are not involved in the microglial uptake of DHA-d5.

Biosynthesis of the Sex Pheromone Component (E,Z)-7,9-Dodecadienyl Acetate in the European Grapevine Moth, Lobesia botrana, Involving ∆11 Desaturation and an Elusive ∆7 Desaturase.

The European grapevine moth, Lobesia botrana, uses (E,Z)-7,9-dodecadienyl acetate as its major sex pheromone component. Through in vivo labeling experiments we demonstrated that the doubly unsaturated pheromone component is produced by ∆11 desaturation of tetradecanoic acid, followed by chain shortening of (Z)-11-tetradecenoic acid to (Z)-9-dodecenoic acid, and subsequently introduction of the second double bond by an unknown ∆7 desaturase, before final reduction and acetylation. By sequencing and analyzing the transcriptome of female pheromone glands of L. botrana, we obtained 41 candidate genes that may be involved in sex pheromone production, including the genes encoding 17 fatty acyl desaturases, 13 fatty acyl reductases, 1 fatty acid synthase, 3 acyl-CoA oxidases, 1 acetyl-CoA carboxylase, 4 fatty acid transport proteins and 2 acyl-CoA binding proteins. A functional assay of desaturase and acyl-CoA oxidase gene candidates in yeast and insect cell (Sf9) heterologous expression systems revealed that Lbo_PPTQ encodes a ∆11 desaturase producing (Z)-11-tetradecenoic acid from tetradecanoic acid. Further, Lbo_31670 and Lbo_49602 encode two acyl-CoA oxidases that may produce (Z)-9-dodecenoic acid by chain shortening (Z)-11-tetradecenoic acid. The gene encoding the enzyme introducing the E7 double bond into (Z)-9-dodecenoic acid remains elusive even though we assayed 17 candidate desaturases in the two heterologous systems.

Ichthyosis prematurity syndrome in two Omani siblings, caused by homozygous c.1A > G mutation in the FATP4 gene.

Ichthyosis prematurity syndrome (IPS) is a rare type of syndromic autosomal recessive congenital ichthyosis (ARCI) caused by a mutation in the SLC27A4 gene that encodes the fatty acid transport protein 4 (FATP4), which is responsible for keratinocyte differentiation and skin barrier function. IPS is characterized by a triad of prematurity, perinatal respiratory asphyxia, and thick vernix caseosa-like scales. In this report, we present the clinical and molecular characterization of IPS in two Omani siblings.

Species-specific metabolic responses of songbird, shorebird, and murine cultured myotubes to n-3 polyunsaturated fatty acids.

Migratory birds may benefit from diets rich in polyunsaturated fatty acids (PUFAs) that could improve exercise performance. Previous investigations suggest that different types of birds may respond differently to PUFA. We established muscle myocyte cell culture models from muscle satellite cells of a migratory passerine songbird (yellow-rumped warbler, Setophaga coronata coronata) and a nonpasserine shorebird (sanderling, Calidris alba). We differentiated and treated avian myotubes and immortalized murine C2C12 myotubes with n-3 PUFA docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), and with monounsaturated oleic acid (OA) to compare effects on aerobic performance, metabolic enzyme activities, key fatty acid (FA) transporters, and expression of peroxisome proliferator-activated receptors (PPARs). Sanderling and C2C12 myotubes increased expression of PPARs with n-3 PUFA treatments, whereas expression was unchanged in yellow-rumped warblers. Both sanderlings and yellow-rumped warblers increased expression of fatty acid transporters, whereas C2C12 cells decreased expression following n-3 PUFA treatments. Only yellow-rumped warbler myotubes increased expression of some metabolic enzymes, whereas the sanderling and C2C12 cells were unchanged. PUFA supplementation in C2C12 myotubes increased mitochondrial respiratory chain efficiency, whereas sanderlings increased proton leak-associated respiration and maximal respiration (measurements were not made in warblers). This research indicates that songbirds and shorebirds respond differently to n-3 PUFA and provides support for the hypothesis that n-3 PUFA increase the aerobic capacity of migrant shorebird muscle, which may improve overall endurance flight performance.

Acyl-CoA synthetases, Aal4 and Aal7, are involved in the utilization of exogenous fatty acids in Yarrowia lipolytica.

The yeast Yarrowia lipolytica assimilates hydrophobic compounds, such as n-alkanes and fatty acids, as sole carbon and energy sources. It has been shown that the acyl-CoA synthetase (ACS) genes, FAT1 and FAA1, are involved in the activation of fatty acids produced during the metabolism of n-alkanes, but the ACS genes that are involved in the metabolism of fatty acids from the culture medium remains to be identified. In this paper, we have identified the ACS genes involved in the utilization of exogenous fatty acids. RNA-seq analysis and qRT-PCR revealed that the transcript levels of the peroxisomal ACS-like protein-encoding genes AAL4 and AAL7 were increased in the presence of oleic acid. The single deletion mutant of AAL4 or AAL7 and double deletion mutant of AAL4 and AAL7 did not show any defects in the growth on the medium containing glucose, glycerol, n-alkanes, or fatty acids. In contrast, the mutant with deletion of seven genes, FAA1, FAT1-FAT4, AAL4, and AAL7, showed severe growth defects on the medium containing dodecanoic acid or oleic acid. These results suggest that Aal4p and Aal7p play important roles in the metabolism of exogenous fatty acids in collaboration with Faa1p and Fat1p-Fat4p.