Fatty Acid Elongase Research Articles

How does habitat influence metabolism? Clues from biomarker response and contaminant profile in Tursiops truncatus (Montagu, 1821) subspecies living in parapatry

In western South America (WSA) two subspecies of bottlenose dolphin are recognized: Tursiops truncatus gephyreus, predominantly found in estuaries and river mouths, and Tursiops truncatus truncatus, occurring along the continental shelf. Despite a partial spatial overlap, both subspecies are considered to occupy different habitats and ecological niches. In the present study, chemical analyzes as well as biochemical and molecular biomarkers were used to investigate the influence of niche partitioning over metabolic pathways associated with the detoxification of persistent organic pollutants (POPs), antioxidant metabolism, immune activity and lipid metabolism in Tursiops truncatus subspecies living in parapatry. Overall, the profile and levels of bioaccumulated PCBs, pesticides and PBDEs were similar between groups, with a greater variety of pesticides, such as γ-HCHs, heptachlor, oxychlordane and o,p'DDT, detected in T. truncatus gephyreus. Multivariate analysis of variance (MANOVA) and non-metric multidimensional scaling (NMDS) results indicated that glutathione reductase (GR) and superoxide dismutase (SOD) enzymatic activities were higher in coastal dolphins, as were the mRNA levels of metallothionein 2A (MT2A), interleukin-1α (IL-1α), ceramide synthase 3 (CERS3) and fatty acid elongase (ELOVL4). In parallel, mRNA levels of fatty acid synthase complex 1 (FASN 1) were higher in oceanic dolphins. These findings suggest that, due to their occurrence in coastal habitats, T. truncatus gephyreus is more exposed to environmental pollutants and pathogenic microorganisms. Likewise, niche partitioning may influence lipid biosynthesis, possibly due to differences on feeding habits, reflecting in an enhanced long chain ceramides biosynthesis in T. truncatus gephyreus. Collectively, these data reinforce the need to address habitat specificities in conservation efforts, since distinct groups can be facing different anthropogenic pressures in WSA.

The fatty acid elongase Elovl6 is crucial for hematopoietic stem cell engraftment and leukemia propagation

The fatty acid elongase Elovl6 is crucial for hematopoietic stem cell engraftment and leukemia propagation

Fatty Acid Profile and Genetic Variants of Proteins Involved in Fatty Acid Metabolism Could Be Considered as Disease Predictor.

Circulating fatty acids (FA) have an endogenous or exogenous origin and are metabolized under the effect of many enzymes. They play crucial roles in many mechanisms: cell signaling, modulation of gene expression, etc., which leads to the hypothesis that their perturbation could be the cause of disease development. FA in erythrocytes and plasma rather than dietary FA could be used as a biomarker for many diseases. Cardiovascular disease was associated with elevated trans FA and decreased DHA and EPA. Increased arachidonic acid and decreased Docosahexaenoic Acids (DHA) were associated with Alzheimer's disease. Low Arachidonic acid and DHA are associated with neonatal morbidities and mortality. Decreased saturated fatty acids (SFA), increased monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) (C18:2 n-6 and C20:3 n-6) are associated with cancer. Additionally, genetic polymorphisms in genes coding for enzymes implicated in FA metabolism are associated with disease development. FA desaturase (FADS1 and FADS2) polymorphisms are associated with Alzheimer's disease, Acute Coronary Syndrome, Autism spectrum disorder and obesity. Polymorphisms in FA elongase (ELOVL2) are associated with Alzheimer's disease, Autism spectrum disorder and obesity. FA-binding protein polymorphism is associated with dyslipidemia, type 2 diabetes, metabolic syndrome, obesity, hypertension, non-alcoholic fatty liver disease, peripheral atherosclerosis combined with type 2 diabetes and polycystic ovary syndrome. Acetyl-coenzyme A carboxylase polymorphisms are associated with diabetes, obesity and diabetic nephropathy. FA profile and genetic variants of proteins implicated in FA metabolism could be considered as disease biomarkers and may help with the prevention and management of diseases.

ELOVL fatty acid elongase 7 (ELOVL7), upregulated by Mdr2-knockout, predicts advanced liver fibrosis in patients with chronic hepatitis B.

This study aims to investigate the correlations between gene alterations induced in Mdr2-knockout (Mdr2-/-) models and liver fibrosis. The overlapping genes in Mdr2-/- models were determined and included in logistic regression analysis to identify potential candidates for predicting liver fibrosis. Correlations between the expression levels of the identified candidates and hepatic stellate cells (HSCs) were addressed. Functional enrichment of the identified candidates was also evaluated via bioinformatic analysis. Twenty-two overlapping genes in the GSE4612, GSE8642 and GSE14539 datasets were identified. Univariate and multivariate analysis indicated that ELOVL fatty acid elongase 7 (ELOVL7) was significantly associated with liver fibrosis S ≥ 2 (OR = 11.8, 95% CI = 2.0 - 69.2, p = 0.006). ELOVL7 was significantly upregulated in patients with various types of liver injury including hepatitis B virus (HBV) infection and fatty liver diseases, and in multiple liver injury models, including bile duct ligation (BDL), carbon tetrachloride (CCl4) and paracetamol injection-induced liver damage models (all p < 0.05). The ELOVL7 levels were significantly higher in HSCs than in other liver cells (all p < 0.05) and were significantly upregulated in activated HSCs compared to quiescent HSCs (all p < 0.05). In addition, ELOVL7 expression was positively associated with transforming growth factor β (TGFβ) and bone morphogenic protein 9 (BMP9) expression and negatively associated with BMP7 expression. Bioinformatic analysis of functional enrichment indicated that ELOVL7 is mainly involved in fatty acid synthesis and metabolism. ELOVL7 could accurately predict advanced liver fibrosis. It might be involved in the activation of HSCs and the TGFβ signaling pathway.

Inner nuclear membrane proteins Lem2 and Bqt4 interact with different lipid synthesis enzymes in fission yeast.

The nuclear envelope (NE) is a double-membrane structure consisting of inner and outer membranes that spatially separate the nucleus from the cytoplasm, and its function is critical for cellular functions such as genome maintenance. In the fission yeast, Schizosaccharomyces pombe, the inner nuclear membrane proteins, Lem2 and Bqt4, play pivotal roles in maintaining the NE structure. We previously found that the double deletion of lem2+ and bqt4+ causes a synthetic lethal defect associated with severe NE rupture, and overexpression of Elo2, a solo very-long-chain fatty acid elongase, suppresses this defect by restoring the NE. However, the molecular basis of this restoration remains elusive. To address this, we identified Lem2- and Bqt4-binding proteins via immunoprecipitation and mass spectrometry in this study. Forty-five and 23 proteins were identified as Lem2- and Bqt4-binding proteins, respectively. Although these binding proteins partially overlapped, Lem2 and Bqt4 interacted with different types of lipid metabolic enzymes: Cho2, Ole1 and Erg11 for Lem2 and Cwh43 for Bqt4. These enzymes are known to be involved in various lipid synthesis processes, suggesting that Lem2 and Bqt4 may contribute to the regulation of lipid synthesis by binding to these enzymes.

Alterations in hepatic transcriptome and cecum microbiota underlying potential ways to prevent early fatty liver in laying hens

Fatty liver syndrome (FLS) is a kind of nutritional metabolic disease in laying hens. Revealing FLS pathogenesis during the early period is what really makes sense for the prevention or nutritional regulation strategies. In the study, 9 healthy or naturally occurring early FLS birds were screened based on visual inspection, liver index and morphologic analysis. Liver and fresh cecal content samples were collected. Then transcriptomic and 16S rRNA technologies are applied to investigate hepatic transcriptome and cecum microbiota composition. Unpaired Student t test and some omics methods were used for statistical analysis. Results showed higher liver weight and index were found in FLS group; morphologic analysis indicated that there existed more lipid droplets in the liver of birds with FLS. Based on DESeq2 analysis, there were 229 up- and 487 down-regulated genes in the FLS group, among which most genes related to de novo fatty acid synthesis were up-regulated such as acetyl-CoA carboxylase, fatty acid synthase, stearoyl-CoA desaturase, and ELOVL fatty acid elongase 6 (ELOVL6). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that pathways associated with lipid metabolism and liver damage were affected. 16S rRNA sequencing analysis of cecum microbiota showed that there was a significant difference between the Con and FLS groups. LEfSe analysis revealed that the relative abundance of Coprococcus, Odoribacter, Collinsella, Turicibacter, YRC22, Enterococcus, Shigella, and Bifidobacterium were down-regulated in the FLS group, whereas the abundance of Bacteroides, Mucispirillum, Butyricicoccus, Campylobacter, Akkermansia, and Clostridium were up-regulated. The KEGG enrichment from differential microbiota suggested that some metabolism-related functions were altered to some extent. Taken together, during the developmental of early fatty liver of laying hens, lipogenesis was enhanced, whereas abnormal metabolism occurs not only in lipid transportation but also in hydrolysis, which caused structural damage to the liver organ. Moreover, the dysbiosis of the cecum microbiota occurred. All of these serve as targets or provide theoretical references for the development of probiotics for fatty liver prevention in laying hens.

Elongases of Long-Chain Fatty Acids ELO2 and ELO9 Are Involved in Cuticle Formation and Function in Fecundity in the Yellow Fever Mosquito, Aedes aegypti

Long-chain fatty acid elongases (ELOs) play important roles in the metabolism of fatty acids in insects. In this study, the genes for two elongases from Aedes aegypti were identified, AeELO2 and AeELO9. Quantitative real time PCR showed that AeELO2 and AeELO9 are expressed at all developmental stages and some body parts, but with different expression patterns. RNAi-mediated knockdown of AeELO2 and AeELO9 was performed to investigate their roles in the development, growth, osmotic balance, and cold tolerance of Ae. aegypti. Knockdown of AeELO2 slowed larval growth and development by causing molting abnormalities. Additionally, 33% ± 3.3% of adults died during oviposition, accompanied by an abnormal extension of cuticles in AeELO2-dsRNA knockdown mosquitos. Knockdown of AeEL09 resulted in abnormal balance of cuticular osmotic pressure and a reduction in egg production. The maximal mRNAs of AeELO2 and AeELO9 were detected in eggs at 72 h after oviposition. Moreover, AeELO2 knockdown reduced the egg hatching rates and AeELO9 knockdown larvae did not develop well. In summary, AeELO2 is involved in larval molting and growth, and its knockdown affects the flexibility and elasticity of adult mosquito cuticles. AeELO9 regulates cold tolerance, osmotic balance, and egg development in Ae. aegypti.

Horse-Derived Ceramide Accentuates Glucosylceramide Synthase and Ceramide Synthase 3 by Activating PPARβ/δ and/or PPARγ to Stimulate Ceramide Synthesis

Horse-derived ceramide (HC), which contains galactosylceramides as its main component, significantly improves skin symptoms when applied topically to patients with atopic dermatitis. We speculated that efficacy resulted from the amelioration of epidermal ceramide metabolism, and we characterized those effects using reconstructed human epidermal equivalents. Lipid analysis, RT-PCR and Western blotting revealed that HC significantly increased the total ceramide content of the stratum corneum (SC), accompanied by significantly increased gene and/or protein expression levels of ceramide synthase (CERS) 3, fatty acid elongase (ELOVL) 4, glucosylceramide synthase (GCS), β-glucocerebrosidase, sphingomyelin synthase and acid sphingomyelinase. Mechanistic analyses using cultures of primary human keratinocytes revealed the marked stimulatory effects of HC on the mRNA expression levels of CERS3, ELOVL4 and GCS under high calcium-derived differentiation conditions. Signaling analyses demonstrated that an antagonist of PPARβ/δ significantly abrogated the HC-stimulated mRNA expression levels of GCS, CERS3 and ELOVL4. GW9662, an antagonist of PPARγ, significantly abolished the HC-up-regulated mRNA expression levels of GCS and ELOVL4, but not of CERS3. These findings suggest that HC has the distinct potential to accentuate the expression of GCS, CERS3 and ELOVL4 via the activation of PPARβ/δ and/or PPARγ to accelerate ceramide synthesis in the SC.

Incomplete Elongation of Ultra-long-chain Polyunsaturated Acyl-CoAs by the Fatty Acid Elongase ELOVL4 in Spinocerebellar Ataxia Type 34.

Spinocerebellar ataxias (SCAs) are autosomal dominant diseases characterized by cerebellar atrophy and ataxia. The SCA subtype SCA34 is caused by specific mutations in the gene ELOVL4, which encodes a fatty acid (FA) elongase that synthesizes ultra-long-chain (ULC; ≥C26) FAs. However, the pathogenesis and molecular mechanism that confers dominant inheritance remains unknown. Here, a cell-based assay demonstrated that each of the five known SCA34 mutants produced shorter ULC polyunsaturated FA-containing phosphatidylcholines (ULC-PCs) than wild-type protein, in the following order of severity: Q180P and T233M > W246G > I171T and L168F. Next, we generated knock-in mouse embryonic stem cells that contained heterozygous Q180P, heterozygous W246G, or homozygous W246G mutations. Neuronal differentiation-dependent production of ULC-PCs was reduced in heterozygous Q180P and homozygous W246G cells relative to control cells, and we observed shortening of the FA moiety in all mutant cells. This FA shortening was consistent with our prediction that amino acid residues substituted by SCA34 mutations are located in the transmembrane helices that interact with the ω-end region of the FA moiety of the substrate acyl-CoA. Hence, reduced levels and shortening of ULC-PCs in neurons may cause SCA34, and incomplete elongation of ULC polyunsaturated acyl-CoAs by mutated ELOVL4 may induce dominant inheritance.

Fenclorim rice safening and weed control with fall‐applied acetochlor and pyroxasulfone

AbstractApplications of very long‐chained fatty acid elongase (VLCFA)‐inhibiting herbicides are currently not labeled within U.S. rice (Oryza sativa L.) production but have been used in Asian rice production to suppress weedy rice and control other annual grasses and small‐seeded broadleaves. Therefore, separate experiments were initiated in the fall of 2019 and 2020 to evaluate rice tolerance and weedy rice (O. sativa L.) control with acetochlor and pyroxasulfone in the following spring. A three‐factor experiment within a randomized complete block design was implemented with the factors being (1) herbicide choice (acetochlor or pyroxasulfone), (2) a low or high herbicide rate (2100 and 4200 g ai ha−1, and at 237 and 475 g ai ha−1 acetochlor and pyroxasulfone, respectively), and (3) without or with a fenclorim seed treatment (2.5 g ai kg−1 of seed). Throughout the experiments, rice exhibited &lt;10% injury with acetochlor. The fenclorim seed treatment reduced injury (averaged over herbicide choice and rate) from 28% to 21% 28 days after emergence of rice for both trial types. Fenclorim also improved rough‐rice yield (averaged over herbicide choice and rate) by 12 and 18 percentage points for the two different studies. However, regardless of fenclorim, rice did not demonstrate &lt;20% injury with pyroxasulfone. The fenclorim seed treatment or any interaction containing fenclorim did not influence weedy rice control, and weedy rice control with acetochlor ranged from 0% to 48%. Findings from this experiment demonstrate the effects of a fenclorim seed treatment for fall‐applied acetochlor and pyroxasulfone and the efficacy of acetochlor and pyroxasulfone for controlling weedy rice.

Tackling functional redundancy of Arabidopsis fatty acid elongase complexes.

Very-long-chain fatty acids (VLCFA) are precursors for various lipids playing important physiological and structural roles in plants. Throughout plant tissues, VLCFA are present in multiple lipid classes essential for membrane homeostasis, and also stored in triacylglycerols. VLCFA and their derivatives are also highly abundant in lipid barriers, such as cuticular waxes in aerial epidermal cells and suberin monomers in roots. VLCFA are produced by the fatty acid elongase (FAE), which is an integral endoplasmic reticulum membrane multi-enzymatic complex consisting of four core enzymes. The 3-ketoacyl-CoA synthase (KCS) catalyzes the first reaction of the elongation and determines the chain-length substrate specificity of each elongation cycle, whereas the other three enzymes have broad substrate specificities and are shared by all FAE complexes. Consistent with the co-existence of multiple FAE complexes, performing sequential and/or parallel reactions to produce the broad chain-length-range of VLCFA found in plants, twenty-one KCS genes have been identified in the genome of Arabidopsis thaliana. Using CRISPR-Cas9 technology, we established an expression platform to reconstitute the different Arabidopsis FAE complexes in yeast. The VLCFA produced in these yeast strains were analyzed in detail to characterize the substrate specificity of all KCS candidates. Additionally, Arabidopsis candidate proteins were transiently expressed in Nicotiana benthamiana leaves to explore their activity and localization in planta. This work sheds light on the genetic and biochemical redundancy of fatty acid elongation in plants.

Staphylococcus aureus causes aberrant epidermal lipid composition and skin barrier dysfunction.

Staphylococcus (S) aureus colonization is known to cause skin barrier disruption in atopic dermatitis (AD) patients. However, it has not been studied how S. aureus induces aberrant epidermal lipid composition and skin barrier dysfunction. Skin tape strips (STS) and swabs were obtained from 24 children with AD (6.0 ± 4.4 years) and 16 healthy children (7.0 ± 4.5 years). Lipidomic analysis of STS samples was performed by mass spectrometry. Skin levels of methicillin-sensitive and methicillin-resistant S. aureus (MSSA and MRSA) were evaluated. The effects of MSSA and MRSA were evaluated in primary human keratinocytes (HEKs) and organotypic skin cultures. AD and organotypic skin colonized with MRSA significantly increased the proportion of lipid species with nonhydroxy fatty acid sphingosine ceramide with palmitic acid ([N-16:0 NS-CER], sphingomyelins [16:0-18:0 SM]), and lysophosphatidylcholines [16:0-18:0 LPC], but significantly reduced the proportion of corresponding very long-chain fatty acids (VLCFAs) species (C22-28) compared to the skin without S. aureus colonization. Significantly increased transepidermal water loss (TEWL) was found in MRSA-colonized AD skin. S. aureus indirectly through interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-33 inhibited expression of fatty acid elongase enzymes (ELOVL3 and ELOVL4) in HEKs. ELOVL inhibition was more pronounced by MRSA and resulted in TEWL increase in organotypic skin. Aberrant skin lipid profiles and barrier dysfunction are associated with S. aureus colonization in AD patients. These effects are attributed to the inhibition of ELOVLs by S. aureus-induced IL-1β, TNF-α, IL-6, and IL-33 seen in keratinocyte models and are more prominent in MRSA than MSSA.

Improved fatty acid composition of field cress (Lepidium campestre) by CRISPR/Cas9-mediated genome editing.

The wild species field cress (Lepidium campestre) has the potential to become a novel cover and oilseed crop for the Nordic climate. Its seed oil is however currently unsuitable for most food, feed, and industrial applications, due to the high contents of polyunsaturated fatty acids (PUFAs) and erucic acid (C22:1). As the biosynthesis of these undesirable fatty acids is controlled by a few well-known major dominant genes, knockout of these genes using CRISPR/Cas9 would thus be more effective in improving the seed oil quality. In order to increase the level of the desirable oleic acid (C18:1), and reduce the contents of PUFAs and C22:1, we targeted three important genes FATTY ACID ELONGASE1 (FAE1), FATTY ACID DESATURASE2 (FAD2), and REDUCED OLEATE DESATURASE1 (ROD1) using a protoplast-based CRISPR/Cas9 gene knockout system. By knocking out FAE1, we obtained a mutated line with almost no C22:1, but an increase in C18:1 to 30% compared with 13% in the wild type. Knocking out ROD1 resulted in an increase of C18:1 to 23%, and a moderate, but significant, reduction of PUFAs. Knockout of FAD2, in combination with heterozygous FAE1fae1 genotype, resulted in mutated lines with up to 66% C18:1, very low contents of PUFAs, and a significant reduction of C22:1. Our results clearly show the potential of CRISPR/Cas9 for rapid trait improvement of field cress which would speed up its domestication process. The mutated lines produced in this study can be used for further breeding to develop field cress into a viable crop.

Identification of key microRNAs regulating ELOVL6 and glioblastoma tumorigenesis

ELOVL fatty acid elongase 6 (ELOVL6) controls cellular fatty acid (FA) composition by catalyzing the elongation of palmitate (C16:0) to stearate (C18:0) and palmitoleate (C16:1n-7) to vaccinate (C18:1n-7). Although the transcriptional regulation of ELOVL6 has been well studied, the post-transcriptional regulation of ELOVL6 is not fully understood. Therefore, this study aims to evaluate the role of microRNAs (miRNAs) in regulating human ELOVL6. Bioinformatic analysis identified five putative miRNAs: miR-135b-5p, miR-135a-5p, miR-125a-5p, miR-125b-5p, and miR-22–3p, which potentially bind ELOVL6 3′-untranslated region (UTR). Results from dual-luciferase assays revealed that these miRNAs downregulate ELOVL6 by directly interacting with the 3′-UTR of ELOVL6 mRNA. Moreover, miR-135b-5p and miR-135a-5p suppress cell proliferation and migration in glioblastoma multiforme cells by inhibiting ELOVL6 at the mRNA and protein levels. Taken together, our results provide novel regulatory mechanisms for ELOVL6 at the post-transcriptional level and identify potential candidates for the treatment of patients with glioblastoma multiforme.

A Blood-Based Molecular Clock for Biological Age Estimation.

In the last decade, extensive efforts have been made to identify biomarkers of biological age. DNA methylation levels of ELOVL fatty acid elongase 2 (ELOVL2) and the signal joint T-cell receptor rearrangement excision circles (sjTRECs) represent the most promising candidates. Although these two non-redundant biomarkers echo important biological aspects of the ageing process in humans, a well-validated molecular clock exploiting these powerful candidates has not yet been formulated. The present study aimed to develop a more accurate molecular clock in a sample of 194 Italian individuals by re-analyzing the previously obtained EVOLV2 methylation data together with the amount of sjTRECs in the same blood samples. The proposed model showed a high prediction accuracy both in younger individuals with an error of about 2.5 years and in older subjects where a relatively low error was observed if compared with those reported in previously published studies. In conclusion, an easy, cost-effective and reliable model to measure the individual rate and the quality of aging in human population has been proposed. Further studies are required to validate the model and to extend its use in an applicative context.

Effects of dietary n-6 polyunsaturated fatty acids (PUFA) composition on growth performances and non-specific immunity in pacific white shrimp (Litopenaeus vannamei)

This study was aimed to investigate the effects of dietary arachidonic acid (ARA) and linoleic acid (LA) on growth, fatty acid composition, antioxidant capacity and immunity of Litopenaeus vannamei. Eight diets were prepared with different LA or ARA content and approximately equal amounts of α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), including a control diet (CK0) without ARA and LA supplementation. 720 shrimp were fed above diets in triplicate for 56 days. The results showed that, the specific growth rate (SGR) and weight gain (WG) of shrimp fed the experimental diets were significantly enhanced compared to the control group. In general, the content of LA or ARA in the experimental shrimp tissues closely mirrored their respective dietary fatty acid levels. The expressions of delta 6 fatty acid desaturase (Δ6FAD) and fatty acid elongase 5 (Elovl5) genes in the intestine and hepatopancreas increased significantly with increasing dietary LA from 5.3 to 9.5, or ARA from 0.2 to 11.1 g kg−1. The activities of superoxide dismutase (SOD) and catalase (CAT), and content of malondialdehyde (MDA) decreased with increasing dietary LA from 5.3 to 9.5, or ARA from 0.2 to 3.8 g kg−1, then increased as dietary LA increased to 16.2, or ARA increased to 11.1 g kg−1. The activities of lysozyme (LZM), acid phosphatase (ACP) and alkine phosphatase (AKP) increased accordingly with the increase of dietary LA from 5.3 to 9.5 or ARA from 0.2 to 1.9 g kg−1. SOD and CAT gene expressions were opposite to the enzyme activity in ARA groups. The results suggested that appropriate dietary LA (9.5 g kg−1) or ARA (3.8 g kg−1) had positively effects on growth, EPA biosynthesis, antioxidant ability and immunity of L. vannamei.

Withdrawal: Circ_0008078 inhibits EC cell tumour properties by miR-191-5p-dependent regulation of ELOVL4.

Esophagus cancer (EC) is an aggressive malignant cancer in the world, and its progression involves the regulation of circular RNA (circRNA). This study is designed to reveal the role of circ_0008078 in EC development and the underlying mechanism. RNA expression of circ_0008078, miR-191-5p, ELOVL fatty acid elongase 4 (ELOVL4), cyclin D1, and proliferating cell nuclear antigen (PCNA) was detected by qRT-PCR or Western blotting. Nuclear proliferation marker (Ki67) expression was analyzed by immunohistochemistry (IHC) assay. The overall survival rate of EC patients was assessed by Kaplan-Meier method. Cell proliferation, apoptosis, angiogenesis ability, migration, and invasion were investigated by 5-Ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry analysis, tube formation assay, wound-healing assay, and transwell invasion assay, respectively. The associations among circ_0008078, miR-191-5p, and ELOVL4 were identified by dual-luciferase reporter assay. Circ_0008078 expression was downregulated in EC tissues (N=35) and cells compared with normal esophageal tissues (N=35) and cells (P<0.0001). Low circ_0008078 expression predicted a poor prognosis for EC patients (P=0.0068). The increased expression of circ_0008078 led to inhibition on cell proliferation, tube formation, migration and invasion but promotion on cell apoptosis (P<0.0001). Re-expression of miR-191-5p, a target miRNA of circ_0008078, attenuated circ_0008078 overexpression-induced effects in EC cells (P<0.0001). In addition, miR-191-5p combined with ELOVL4 to regulate EC cell tumor properties. Circ_0008078 induced ELOVL4 expression by negatively modulating miR-191-5p (P<0.0001). Further, ectopic expression of circ_0008078 inhibited EC cell malignancy in vivo (P<0.001). Circ_0008078 inhibited EC cell malignancy by the miR-191-5p/ELOVL4 pathway, providing a possible target for EC therapy.

Evaluation of rice tolerance and weed control with acetochlor and fenclorim

AbstractMany problematic weeds have evolved resistance to herbicides in mid-southern U.S. rice fields. With the lack of new effective herbicides, rice producers seek alternatives that are currently not labeled for rice production. Inhibitors of very-long chain fatty acid elongase (VLCFA) are currently not labeled for use with U.S. rice crops but are labeled for use in other U.S. row cropping systems and rice production in Asia. Previous research has demonstrated the utility of VLCFA inhibitors for weed control in rice; however, these herbicides induce variable amounts of injury to the crop when applied early in the growing season. Experiments were initiated in 2020 and 2021 at the Rice Research and Extension Center near Stuttgart, AR, to evaluate rice tolerance and weed control with acetochlor and seed treatment with a herbicide safener, fenclorim. Three rates of a microencapsulated formulation of acetochlor (630, 1,260, and 1,890 g ai ha−1), four application timings (preemergence, PRE; delayed-preemergence, DPRE; spiking; and 1-leaf), and without or with the fenclorim seed treatment (2.5 g kg−1 of seed) were used to evaluate rice tolerance, weedy rice control, and barnyardgrass control. Acetochlor applied DPRE at 1,260 g ai ha−1 provided better weedy rice and barnyardgrass control than applications at the 1-leaf stage at the same rate. Acetochlor rates of 1,260 and 1,890 g ai ha−1 reduced barnyardgrass and weedy rice densities by more greater than the 630 g ai ha−1 rate. The fenclorim seed treatment did not influence weedy rice or barnyardgrass control but did reduce injury for DPRE acetochlor applications. Based on these results, acetochlor can be safely applied to rice DPRE (≤19% injury) at 1,260 g ai ha−1 when the seed is treated with fenclorim, leading to ≥88% barnyardgrass and ≥45% weedy rice control 28 d after treatment.

The LXRB-SREBP1 network regulates lipogenic homeostasis by controlling the synthesis of polyunsaturated fatty acids in goat mammary epithelial cells

BackgroundIn rodents, research has revealed a role of liver X receptors (LXR) in controlling lipid homeostasis and regulating the synthesis of polyunsaturated fatty acids (PUFA). Recent data suggest that LXRB is the predominant LXR subtype in ruminant mammary cells, but its role in lipid metabolism is unknown. It was hypothesized that LXRB plays a role in lipid homeostasis via altering the synthesis of PUFA in the ruminant mammary gland. We used overexpression and knockdown of LXRB in goat primary mammary epithelial cells (GMEC) to evaluate abundance of lipogenic enzymes, fatty acid profiles, content of lipid stores and activity of the stearoyl-CoA desaturase (SCD1) promoter.ResultsOverexpression of LXRB markedly upregulated the protein abundance of LXRB while incubation with siRNA targeting LXRB markedly decreased abundance of LXRB protein. Overexpression of LXRB plus T0901317 (T09, a ligand for LXR) dramatically upregulated SCD1 and elongation of very long chain fatty acid-like fatty acid elongases 5–7 (ELOVL 5–7), which are related to PUFA synthesis. Compared with the control, cells overexpressing LXRB and stimulated with T09 had greater concentrations of C16:0, 16:1, 18:1n7,18:1n9 and C18:2 as well as desaturation and elongation indices of C16:0. Furthermore, LXRB-overexpressing cells incubated with T09 had greater levels of triacylglycerol and cholesterol. Knockdown of LXRB in cells incubated with T09 led to downregulation of genes encoding elongases and desaturases. Knockdown of LXRB attenuated the increase in triacylglycerol and cholesterol that was induced by T09. In cells treated with dimethylsulfoxide, knockdown of LXRB increased the concentration of C16:0 at the expense of C18:0, while a significant decrease in C18:2 was observed in cells incubated with both siLXRB and T09. The abundance of sterol regulatory element binding transcription factor 1 precursor (pSREBP1) and its mature fragment (nSREBP1) was upregulated by T09, but not LXRB overexpression. In the cells cultured with T09, knockdown of LXRB downregulated the abundance for pSREBP1 and nSREBP1. Luciferase reporter assays revealed that the activities of wild type SCD1 promoter or fragment with SREBP1 response element (SRE) mutation were decreased markedly when LXRB was knocked down. Activity of the SCD1 promoter that was induced by T09 was blocked when the SRE mutation was introduced.ConclusionThe current study provides evidence of a physiological link between the LXRB and SREBP1 in the ruminant mammary cell. An important role was revealed for the LXRB-SREBP1 network in the synthesis of PUFA via the regulation of genes encoding elongases and desaturases. Thus, targeting this network might elicit broad effects on lipid homeostasis in ruminant mammary gland.

Apolipoprotein H: a novel regulator of fat accumulation in duck myoblasts

Apolipoprotein H (APOH) primarily engages in fat metabolism and inflammatory disease response. This study aimed to investigate the effects of APOH on fat synthesis in duck myoblasts (CS2s) by APOH overexpression and knockdown. CS2s overexpressing APOH showed enhanced triglyceride (TG) and cholesterol (CHOL) contents and elevated the mRNA and protein expression of AKT serine/threonine kinase 1 (AKT1), ELOVL fatty acid elongase 6 (ELOVL6), and acetyl-CoA carboxylase 1 (ACC1) while reducing the expression of protein kinase AMP-activated catalytic subunit alpha 1 (AMPK), peroxisome proliferator activated receptor gamma (PPARG), acyl-CoA synthetase long chain family member 1 (ACSL1), and lipoprotein lipase (LPL). The results showed that knockdown of APOH in CS2s reduced the content of TG and CHOL, reduced the expression of ACC1, ELOVL6, and AKT1, and increased the gene and protein expression of PPARG, LPL, ACSL1, and AMPK. Our results showed that APOH affected lipid deposition in myoblasts by inhibiting fatty acid beta-oxidation and promoting fatty acid biosynthesis by regulating the expression of the AKT/AMPK pathway. This study provides the necessary basic information for the role of APOH in fat accumulation in duck myoblasts for the first time and enables researchers to study the genes related to fat deposition in meat ducks in a new direction.