Lipid Biosynthesis Research Articles

Loss of transcriptional regulator of phospholipid biosynthesis alters post-translational modification of Sec61 translocon beta subunit Sbh1 in Saccharomyces cerevisiae.

We recently discovered that disrupting phospholipid biosynthesis by eliminating the Ino2/4 transcriptional regulator impairs endoplasmic reticulum (ER)-associated degradation (ERAD) in Saccharomyces cerevisiae , but the mechanism is unclear. Phosphatidylcholine deficiency has been reported to accelerate degradation of Sec61 translocon beta subunit Sbh1 and ERAD cofactor Cue1. Here, we found that, unlike targeted phosphatidylcholine depletion, INO4 deletion does not destabilize Sbh1 or Cue1. However, we observed altered electrophoretic mobility of Sbh1 in ino4 Δ yeast, consistent with phospholipid-responsive post-translational modification. A better understanding of the molecular consequences of disrupted lipid homeostasis could lead to enhanced treatments for conditions associated with perturbed lipid biosynthesis.

Maternal dietary antioxidant supplementation regulates weaned piglets' adipose tissue transcriptome and morphology.

Antioxidant supplementation in critical periods may be useful for improvement of piglet early viability and development. We have evaluated the effects of maternal perinatal diet inclusion of a high vitamin E level (VE, 100 mg all-rac-α-tocopheryl acetate /kg), hydroxytyrosol (HT, 1.5 mg/kg), or their combination (VEHT), in comparison to a control diet (C, 30 mg all-rac-α-tocopheryl acetate /kg), on the offspring homeostasis and metabolism, analysing the weaned piglets' adipose tissue transcriptome and adipocyte morphology. Diets were provided to pregnant Iberian sows (n = 48, 12 per treatment) from gestation day 85 to weaning (28 days postpartum) and 48 piglets (n = 12 per treatment) were sampled 5 days postweaning for dorsal subcutaneous adipose tissue analyses. RNA obtained from 6 animals for each diet was used for paired-end RNA sequencing. Results show that supplementation of sows' diet with either vitamin E or hydroxytyrosol had substantial effects on weaned piglet adipose transcriptome, with 664 and 587 genes being differentially expressed, in comparison to C, respectively (q-value<0.10, Fold Change>1.5). Genes upregulated in C were mainly involved in inflammatory and immune response, as well as oxidative stress, and relevant canonical pathways and upstream regulators involved in these processes were predicted as activated, such as TNF, IFNB or NFKB. Vitamin E, when supplemented alone at high dose, activated lipid biosynthesis functions, pathways and regulators, this finding being accompanied by increased adipocyte size. Results suggest an improved metabolic and antioxidant status of adipose tissue in animals born from sows supplemented with individual antioxidants, while the combined supplementation barely affected gene expression, with VEHT showing a prooxidant/proinflamatory functional profile similar to C animals. Different hypothesis are proposed to explain this unexpected result. Findings allow a deeper understanding of the processes taking place in adipose tissue of genetically fat animals and the role of antioxidants in the regulation of fat cells function.

Lipid regulation by early administration of irradiated chitosan and glutathione in heat-stressed broilers

This research was conducted to determine the effect of irradiated chitosan and glutathione on lipid regulation of broiler and its impact on free radical compounds. One hundred broiler starter phase as the objects of research. The study used a completely randomized design (CRD) with experimental protocols method, consisting of nine treatments and three replications. Each replication consist of five broilers, namely P0 = without giving chitosan and glutathione, PA1 = given 100 ppm chitosan from the age of 4-35 days, PA2 = 450 ppm chitosan from the age of 4-35 days, PA3 = 100 ppm chitosan + 150 ppm glutathione from the age of 4-35 days, PA4 = 100 ppm chitosan + 150 ppm glutathione from the age of 4-35 days, PB1 = 300 ppm chitosan from the age of 20-35 days, PB2 = 450 chitosan ppm since the age of 20-35 days, PB3 = 100 ppm chitosan + 150 ppm glutathione since the age of 20-35 days and PA4 = 100 ppm chitosan + 150 ppm glutathione since the age of 20-35 days. Parameters observed in this study, namely regulators and broiler lipid transport (Apo A1, Apo A2, Apo B, Apo C, HDL, LDL), plasma lipids (triglycerides, total cholesterol, NEFA), The results showed that the administration of irradiated chitosan and glutathione had a significant effect (P<0.05) on regulators and broiler lipid transport by fed 450 ppm of irradiated chitosan with 150 ppm of glutathione. Based on the research results, it can be concluded that the administration of irradiated chitosan accompanied by glutathione induction in broiler rations can affect lipid regulation and biochemical aspects and performance as a result of this regulation. Giving chitosan as much as 450 ppm with 150 ppm induced glutathione since the early age of the finisher phase (20 days) was able to regulate lipid biosynthesis optimally with the best final body weight.

Functional modulation of lysophosphatidic acid type 2 G-protein coupled receptor facilitates alveolar bone formation.

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG-35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type-specific responses, with AMG-35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG-35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF-β1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG-35 elicits osteoblast differentiation through TGF-β1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF-β1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG-35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment.

Eco-friendly cultivation of microalgae using a horizontal twin layer system for treatment of real solid waste leachate

Solid waste leachate (SWL) requires dilution with water to offset the negative effects of high nutrient concentration and organic compounds for its microalgae-based treatment. Among attached cultivation systems, twin layer is a technology in which limited information is available on treatment of high strength wastewater using microalgae. Moreover, widespread application of twin layer technology is limited due to cost of substrate and source layer used. In the present study, potential of Scenedesmus sp. for the treatment of SWL was assessed on horizontal twin layer system (HTLS). Novel and cost-effective substrate layers were tested as attachment material. Wetland treated municipal wastewater (WMW) was used to prepare SWL dilutions viz, 5%, 10%, 15%, 20% and 25% SWL. Recycled printing paper showed maximum biomass productivity of 5.19 g m−2 d−1. Among all the SWL dilutions, Scenedesmus sp. achieved maximum growth of 103.05 g m−2 in 5% SWL which was 16% higher than WMW alone. The maximum removal rate of NH4+ –N, TKN, and PO43− P was obtained in 20% SWL which was 1371, 1588 and 153 mg m−2 d−1 respectively. Varying concentrations of nutrients in different SWL dilutions significantly affected lipid biosynthesis, with enhanced productivity of 2.28 g m−2 d−1 achieved in 5% SWL compared to 0.97 g m−2 d−1 in 20% SWL. Hence, it can be concluded that 5% SWL dilution was good for biomass and lipid production, while the highest nutrient removal rates were obtained at 20% SWL mainly attributed to biotic and abiotic processes. Based on these results HTLS can be a promising technology for pilot scale to explore industrialized application of wastewater treatment and algal production.

Analysis of transcriptome differences between subcutaneous and intramuscular adipose tissue of Ningxiang pigs.

To compare and analyze the molecular mechanisms of adipose deposition in subcutaneous fat (SAF)and intramuscular fat (IMF) tissues in Ningxiang pigs, differential gene expression profiles in SAF and IMF tissues of Ningxiang pigs were identified and analysed using RNA-seq technology. Six healthy 250-day-old male Ningxiang pigs with similar body weights (approximately 85 kg) of intraspecific individuals were selected as experimental material and samples of SAF and IMF tissues were collected. Differential genes associated with fat deposition and lipid metabolism were obtained by sequencing two adipose tissue transcriptomes and performing GO (Gene Ontology) functional annotation and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis. To verify the reliability of the sequencing results, six differential genes were randomly selected to validate using qRT-PCR. The results showed that we identified 2406 DEGs, with 1422 up-regulated and 984 down-regulated genes in two tissues. GO functional annotation analysis revealed that the differentially expressed genes were mainly involved in lipid metabolism related pathways, such as steroid biosynthesis, unsaturated fatty acid biosynthesis, glycerophospholipid metabolism and autophagy pathway. KEGG pathway enrichment showed that the differentially expressed genes were mainly enriched in the biological processes related to lipid binding, fatty acid metabolism, glycol ester metabolism, lipid biosynthesis and other biological processes related to lipid metabolism. Genes related to lipid metabolism, such as TCAP, NR4A1, ACACA, LPL, ELOVL6, DGAT1, PRKAA1, ATG101, TP53INP2, FDFT1, ACOX1 and SCD were identified by bioinformatic analyses and verified by qRT-PCR. Our results indicated that these genes may play important roles in the regulation of fat deposition and metabolism in the SAF and IMF tissue, providing the further mechanistic investigation of fat deposition in Ningxiang pigs.

Novel Hydroxamic Acids Containing Aryl-Substituted 1,2,4- or 1,3,4-Oxadiazole Backbones and an Investigation of Their Antibiotic Potentiation Activity.

UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a zinc amidase that catalyzes the second step of the biosynthesis of lipid A, which is an outer membrane essential structural component of Gram-negative bacteria. Inhibitors of this enzyme can be attributed to two main categories, non-hydroxamate and hydroxamate inhibitors, with the latter being the most effective given the chelation of Zn2+ in the active site. Compounds containing diacetylene or acetylene tails and the sulfonic head, as well as oxazoline derivatives of hydroxamic acids, are among the LpxC inhibitors with the most profound antibacterial activity. The present article describes the synthesis of novel functional derivatives of hydroxamic acids-bioisosteric to oxazoline inhibitors-containing 1,2,4- and 1,3,4-oxadiazole cores and studies of their cytotoxicity, antibacterial activity, and antibiotic potentiation. Some of the hydroxamic acids we obtained (9c, 9d, 23a, 23c, 30b, 36) showed significant potentiation in nalidixic acid, rifampicin, and kanamycin against the growth of laboratory-strain Escherichia coli MG1655. Two lead compounds (9c, 9d) significantly reduced Pseudomonas aeruginosa ATCC 27853 growth in the presence of nalidixic acid and rifampicin.

Full-Length Transcriptome and Gene Expression Analysis of Different Ovis aries Adipose Tissues Reveals Transcript Variants Involved in Lipid Biosynthesis.

Sheep have historically been bred globally as a vital food source. To explore the transcriptome of adipose tissue and investigate key genes regulating adipose metabolism in sheep, adipose tissue samples were obtained from F1 Dorper × Hu sheep. High-throughput sequencing libraries for second- and third-generation sequencing were constructed using extracted total RNA. Functional annotation of differentially expressed genes and isoforms facilitated the identification of key regulatory genes and isoforms associated with sheep fat metabolism. SMRT-seq generated 919,259 high-accuracy cDNA sequences after filtering. Full-length sequences were corrected using RNA-seq sequences, and 699,680 high-quality full-length non-chimeric (FLNC) reads were obtained. Upon evaluating the ratio of total lengths based on FLNC sequencing, it was determined that 36,909 out of 56,316 multiple-exon isoforms met the criteria for full-length status. This indicates the identification of 330,375 full-length FLNC transcripts among the 370,114 multiple-exon FLNC transcripts. By comparing the reference genomes, 60,276 loci and 111,302 isoforms were identified. In addition, 43,423 new genes and 44,563 new isoforms were identified. The results identified 185 (3198), 394 (3592), and 83 (3286) differentially expressed genes (transcripts) between tail and subcutaneous, tail and visceral, and subcutaneous and visceral adipose tissues, respectively. Functional annotation and pathway analysis revealed the following observations. (1) Among the differentially expressed genes (DEGs) of TF and SF tissues, the downregulation of ACADL, ACSL6, and NC_056060.1.2536 was observed in SF, while FFAR4 exhibited upregulation. (2) Among the DEGs of TF and VF tissues, expressions of ACADL, ACSL6, COL1A1, COL1A2, and SCD were downregulated in VF, with upregulation of FFAR4. (3) Among SF and VF expressions of COL1A1, COL1A2, and NC_056060.1.2536 were downregulated in VF. Specific differentially expressed genes (ACADL, ACSL6, COL1A1, COL1A2, FFAR4, NC_056060.1.2536, and SCD) and transcripts (NC_056066.1.1866.16 and NC_056066.1.1866.22) were identified as relevant to fat metabolism. These results provide a dataset for further verification of the regulatory pathway associated with fat metabolism in sheep.

Honokiol inhibits Botryosphaeria dothidea, the causal pathogen of kiwifruit soft rot, by targeting membrane lipid biosynthesis.

Kiwifruit soft rot is mainly caused by Botryosphaeria dothidea, representing a considerable threat to kiwifruit industry. This investigation assessed the inhibitory consequences and mechanisms of honokiol against B. dothidea, evaluating the inhibitory effects and underlying mechanism. A strain of B.dothidea (XFCT-2) was isolated from infected soft rot kiwifruit. The findings indicate that honokiol hindered the mycelial growth, conidial germination, and pathogenicity of B. dothidea in a dose-dependent manner, both in vitro and in vivo. Furthermore, ultrastructural examinations showed that honokiol impaired the integrity of B. dothidea, leading to an elevation in cell membrane permeability, engendering a multitude of intracellular substance extravasations and hampering energy metabolism. Transcriptome analysis exhibited that honokiol-regulated genes were related to membrane lipid biosynthesis, comprising ACC1, FAS2, Arp2, gk, Cesle, and Etnk1. These findings indicate that honokiol impedes B. dothidea by obstructing lipid biosynthesis within the cell membrane and compromising its integrity, halting the growth of the mycelia, which could potentially cause cellular demise. This investigation illustrates how honokiol functions as an eco-friendly approach to prevent the occurrence of soft rot in kiwifruits. © 2023 Society of Chemical Industry.

Altering environmental conditions induce shifts in simulated deep terrestrial subsurface bacterial communities-Secretion of primary and secondary metabolites.

The deep terrestrial subsurface (DTS) harbours a striking diversity of microorganisms. However, systematic research on microbial metabolism, and how varying groundwater composition affects the bacterial communities and metabolites in these environments is lacking. In this study, DTS groundwater bacterial consortia from two Fennoscandian Shield sites were enriched and studied. We found that the enriched communities from the two sites consisted of distinct bacterial taxa, and alterations in the growth medium composition induced changes in cell counts. The lack of an exogenous organic carbon source (ECS) caused a notable increase in lipid metabolism in one community, while in the other, carbon starvation resulted in low overall metabolism, suggesting a dormant state. ECS supplementation increased CO2 production and SO4 2- utilisation, suggesting activation of a dissimilatory sulphate reduction pathway and sulphate-reducer-dominated total metabolism. However, both communities shared common universal metabolic features, most probably involving pathways needed for the maintenance of cell homeostasis (e.g., mevalonic acid pathway). Collectively, our findings indicate that the most important metabolites related to microbial reactions under varying growth conditions in enriched DTS communities include, but are not limited to, those linked to cell homeostasis, osmoregulation, lipid biosynthesis and degradation, dissimilatory sulphate reduction and isoprenoid production.

Disturbance of respiration-improved lipid biosynthesis in Auxenochlorella pyrenoidosa (Chlorellaceae, Chlorophyta) under nitrogen limitation

ABSTRACT Understanding the related mechanisms between aerobic respiration and lipid biosynthesis may promote microalgal-biofuel industries through metabolic engineering. However, little is known about how aerobic respiration affects lipid biosynthesis in microalgae. Here, the changes in biochemistry and molecular biology were analysed in Auxenochlorella pyrenoidosa throughout nitrogen limitation (–N) and nitrogen resupply (+N) phases. Respiratory inhibitors were used to identify the roles of respiratory complexes in lipid biosynthesis. We found that during –N phase the growth profiles, and the amount and productivity of chlorophyll a, carbohydrates and proteins decreased, while the content and productivity of lipids increased. In addition, the lower unsaturation (DU ≤ 96.41 ± 0.38) showed that lipid accumulation under nitrogen limitation in A. pyrenoidosa was qualified for biodiesel production. Either relationships or significant correlations were found between lipid contents, reactive oxygen species (ROS), respiration rates, respiratory complexes activities and key gene expression in treatment groups. Moreover, the trends in the activities of complexes I and III, lipid contents and ROS production in +N phase were different from those in –N phase. Finally, the respiratory inhibitors increased the levels of total ROS and lipids in A. pyrenoidosa. These results suggested that nitrogen limitation may inhibit redox centers of complexes I and III in respiratory chains through mitochondria and nucleus, thus regulating intracellular ROS and lipid accumulation.

Identification of genes associated with fatty acid biosynthesis based on 214 safflower core germplasm

BackgroundSafflower (Carthamus tinctorius L.) is an oilseed crop with substantial medicinal and economic value. However, the methods for constructing safflower core germplasm resources are limited, and the molecular mechanisms of lipid biosynthesis in safflower seeds are not well understood.ResultsIn this study, 11 oil-related quantitative traits and 50 pairs of InDel markers were used to assess the diversity of a collection of 605 safflower germplasms. The original safflower germplasm exhibited rich phenotypic diversity, with high variation for most of the phenotypic traits under investigation. Similarly, high genetic diversity was evaluated in the original germplasm, in which the mean Shannon’s information index (I), observed heterozygosity (H0), and expected heterozygosity (He) were 0.553, 0.182, and 0.374, respectively. Four subgroups with strong genetic structures were identified and a core germplasm of 214 cultivars was constructed, which is well represented in the original germplasm. Meanwhile, differential expression analysis of the transcriptomes of high and low linoleic acid safflower varieties at two stages of seed development identified a total of 47 genes associated with lipid biosynthesis. High expression of the genes KAS II and SAD enhanced the synthesis and accumulation of oleic acid, while FAD genes like FAD2 (Chr8G0104100), FAD3, FAD7 and FAD8 promoted the consumption of oleic acid conversion. The coordinated regulation of these multiple genes ensures the high accumulation of oleic acid in safflower seed oil.ConclusionsBased on these findings, a core germplasm of 214 cultivars was constructed and 47 candidate genes related to unsaturated fatty acid biosynthesis and lipid accumulation were identified. These results not only provide guidance for further studies to elucidate the molecular basis of oil lipid accumulation in safflower seeds, but also contribute to safflower cultivar improvements.

Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action.

One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.

Transcriptomic and lipid profiling analysis reveals a functional interplay between testosterone and growth hormone in hypothyroid liver.

Preclinical and clinical studies suggest that hypothyroidism might cause hepatic endocrine and metabolic disturbances with features that mimic deficiencies of testosterone and/or GH. The absence of physiological interactions between testosterone and GH can be linked to male differentiated liver diseases. Testosterone plays relevant physiological effects on somatotropic-liver axis and liver composition and the liver is a primary organ of interactions between testosterone and GH. However, testosterone exerts many effects on liver through complex and poorly understood mechanisms. Testosterone impacts liver functions by binding to the Androgen Receptor, and, indirectly, through its conversion to estradiol, and cooperation with GH. However, the role of testosterone, and its interaction with GH, in the hypothyroid liver, remains unclear. In the present work, the effects of testosterone, and how they impact on GH-regulated whole transcriptome and lipid composition in the liver, were studied in the context of adult hypothyroid-orchiectomized rats. Testosterone replacement positively modulated somatotropic-liver axis and impacted liver transcriptome involved in lipid and glucose metabolism. In addition, testosterone enhanced the effects of GH on the transcriptome linked to lipid biosynthesis, oxidation-reduction, and metabolism of unsaturated and long-chain fatty acids (FA). However, testosterone decreased the hepatic content of cholesterol esters and triacylglycerols and increased fatty acids whereas GH increased neutral lipids and decreased polar lipids. Biological network analysis of the effects of testosterone on GH-regulated transcriptome confirmed a close connection with crucial proteins involved in steroid and fatty acid metabolism. Taken together, this comprehensive analysis of gene expression and lipid profiling in hypothyroid male liver reveals a functional interplay between testosterone and pulsed GH administration.

Metabolic Regulation of Two pksCT Gene Transcripts in Monascus ruber Impacts Citrinin Biosynthesis.

Citrinin (CIT), a secondary metabolite produced by the filamentous fungi Monascus species, exhibits nephrotoxic, hepatotoxic, and carcinogenic effects in mammals, remarkably restricting the utilization of Monascus-derived products. CIT synthesis is mediated through the pksCT gene and modified by multiple genetic factors. Here, the regulatory effects of two pksCT transcripts, pksCTα, and pksCTβ, generated via pre-mRNA alternative splicing (AS), were investigated using hairpin RNA (ihpRNA) interference, and their impact on CIT biosynthesis and the underlying mechanisms were assessed through chemical biology and transcriptome analyses. The CIT yield in ihpRNA-pksCTα and ihpRNA-pksCT (α + β) transformants decreased from 7.2 μg/mL in the wild-type strain to 3.8 μg/mL and 0.08 μg/mL, respectively. Notably, several genes in the CIT biosynthetic gene cluster, specifically mrl3, mrl5, mrr1, and mrr5 in the ihpRNA-pksCT (α + β) transformant, were downregulated. Transcriptome results revealed that silencing pksCT has a great impact on carbohydrate metabolism, amino acid metabolism, lipid metabolism, and AS events. The key enzymes in the citrate cycle (TCA cycle) and glycolysis were significantly inhibited in the transformants, leading to a decrease in the production of biosynthetic precursors, such as acetyl-coenzyme-A (acetyl-coA) and malonyl-coenzyme-A (malonyl-coA). Furthermore, the reduction of CIT has a regulatory effect on lipid metabolism via redirecting acetyl-coA from CIT biosynthesis towards lipid biosynthesis. These findings offer insights into the mechanisms underlying CIT biosynthesis and AS in Monascus, thus providing a foundation for future research.

The gut microbiome across the cardiovascular risk spectrum.

Despite treatment advancements, cardiovascular disease remains a leading cause of death worldwide. Identifying new targets is crucial for enhancing preventive and therapeutic strategies. The gut microbiome has been associated with coronary artery disease (CAD), however our understanding of specific changes during CAD development remains limited. We aimed to investigate microbiome changes in participants without clinically manifest CAD with different cardiovascular risk levels and in patients with ST-elevation myocardial infarction (STEMI). In this cross-sectional study, we characterized the gut microbiome using metagenomics of 411 faecal samples from individuals with low (n = 130), intermediate (n = 130), and high (n = 125) cardiovascular risk based on the Framingham score, and STEMI patients (n = 26). We analysed diversity, and differential abundance of species and functional pathways while accounting for confounders including medication and technical covariates. Collinsella stercoris, Flavonifractor plautii, and Ruthenibacterium lactatiformans showed increased abundances with cardiovascular risk, while Streptococcus thermophilus was negatively associated. Differential abundance analysis revealed eight species and 49 predicted metabolic pathways that were differently abundant among the groups. In the gut microbiome of STEMI patients, there was a depletion of pathways linked to vitamin, lipid, and amino acid biosynthesis. We identified four microbial species showing a gradual trend in abundance from low-risk individuals to those with STEMI, and observed differential abundant species and pathways in STEMI patients compared to those without clinically manifest CAD. Further investigation is warranted to gain deeper understanding of their precise role in CAD progression and potential implications, with the ultimate goal of identifying novel therapeutic targets.

Effect of biotin starvation on gene expression in industrially significant yeast Komagataella phaffii

Komagataella phaffii(Pichia pastoris) is known to be an excellent producer of recombinant proteins for industrial and research purposes. Protein synthesis improvement in this yeast includes selection of optimal cultivation parameters [1, 2]. Therefore, much attention is paid to the influence of media components on physiology of this yeast [3–5].&#x0D; One of the essential media components is biotin. In yeast cells it plays a crucial role as a cofactor of enzymes, providing carboxylation reactions in lipo-, gluconeogenesis, and nitrogen metabolism.K. phaffiiis biotin auxotrophic organism unable to synthesize this vitaminde novo. Thus, it necessarily requires adding of biotin in the media.&#x0D; In this study, we analyzed the effect of biotin starvation on gene expression inK. phaffiicells during its growth on methanol- and glycerin-containing media. These carbon sources are the most commonly used in standard protocols for recombinant protein biosynthesis inK. phaffii.&#x0D; It was shown, that biotin starvation cell response significantly depends on carbon source. In glycerol-containing media biotin deficiency enhanced transcription of genes involved in biotin and thiamine metabolism, glyoxylate cycle, synthesis of acetyl-CoA in cytoplasm and its carnitine-mediated transport into mitochondria. Genes involved in biosynthesis of lipids and glucose were repressed in media with glycerol. In methanol-containing media the biotin deficiency effect was more pronounced and led to repression of numerous genes involved in protein and amino acids synthesis and activation of cell response to oxidative stress.&#x0D; The obtained results are thought to be important for optimizing the culture conditions in theK. phaffiiexpression systems.

Potential of Lipid Biosynthesis under Heterotrophy in the Marine Diatom Cyclotella cryptica.

Despite the theoretical high productivity, microalgae-based oil production is not economically sustainable due to the high cost of photoautotrophic cultures. Heterotrophic growth is a suitable economic alternative to overcoming light dependence and climatic/geographic fluctuations. Here we report data about growth performance, biomass production, and lipid composition of the marine diatom Cyclotella cryptica, chosen as a model strain for biodiesel production in heterothrophy. A repeated-batch process of heterotrophic cultivation has also been investigated to assess the robustness and phenotypic stability. The process consisting of six constant cycle repetitions was carried out for 42 days and led to an average dry biomass production of 1.5 ± 0.1 g L-1 of which 20% lipids composed of 60% triglycerides, 20% phospholipids. and 20% glycolipids. The major fatty acids were C16:0 (∼26%), C16:1 ω-7 (∼57%), and C20:5 ω-3 (∼12%), with a significant reduction in the unsaturated fatty acids in comparison to other microalgae grown in heterotrophy. Fatty acids were differently distributed among the glycerolipid classes, and the lipid composition was used to compare the potential properties of C. cryptica oil with traditional vegetable biofuels.

AMP deaminase: A crucial regulator in nitrogen stress and lipid metabolism in Mucor circinelloides

Lipid biosynthesis is a significant metabolic response to nitrogen starvation in oleaginous fungi. The oleaginous fungus Mucor circinelloides copes with nitrogen stress by degrading AMP through AMP deaminase (AMPD). However, the mechanism of AMPD in regulating lipogenesis remains largely unclear. To elucidate the mechanism of AMPD in lipid synthesis in this M. circinelloides, we identified two genes (ampd1 and ampd2) encoding AMPD and constructed an ampd double knockout mutant. The engineered M. circinelloides strain elevated cell growth and lipid accumulation, as well as the content of oleic acid (OA) and gamma-linolenic acid (GLA). In addition to the expected increase in transcription levels of genes associated with lipid and TAG synthesis, we observed suppression of lipid degradation and reduced amino acid biosynthesis. This suggested that the deletion of AMPD genes induces the redirection of carbon towards lipid synthesis pathways. Moreover, the pathways related to nitrogen metabolism, including nitrogen assimilation and purine metabolism (especially energy level), were also affected in order to maintain homeostasis. Further analysis discovered that the transcription factors (TFs) related to lipid accumulation were also regulated. This study provides new insights into lipid biosynthesis in M. circinelloides, indicating that the trigger for lipid accumulation is not entirely AMPD-dependent and suggest that there may be additional mechanisms involved in the initiation of lipogenesis.

Cholesterol and matrisome pathways dysregulated by APOE4 in human glia

AbstractBackgroundThe association of Apolipoprotein E (APOE) ɛ4 risk with Alzheimer’s disease (AD) is well‐established. However, the impact of APOE ɛ4 on human brain cell function remains unclear. We hypothesized that human APOE ε4/ε4 (APOE 44) genotype contributes to disease risk through cell autonomous and non‐cell autonomous mechanisms in a human cell specific manner.MethodGlobal transcriptomic analyses were performed on astrocytes, microglia, mixed cortical cultures (neurons and astrocytes) and brain microvascular endothelial cells derived from human induced pluripotent stem cells (iPSCs) and post‐mortem AD brains. Lipid pathway dysregulation identified through GSEA, WGCNA and cell type deconvolution was validated in vitro using Gas Chromatography‐Mass Spectrometry (GC‐MS), filipin staining, autophagy fluorescent reporters with immunocytochemistry and western blotting to determine the subcellular compartment that accumulates cholesterol in iPSC‐derived astrocytes, and further confirmed by immunohistochemical analysis in human APOE4 post‐mortem brain. Matrisome pathway dysregulation was validated by Luminex multiplex immunoassays and intracellular protein levels in pure astrocytes and mixed cortical cultures.ResultGlobal transcriptomic analyses reveal that APOE 44 drives cholesterol metabolic dysregulation in astrocytes and microglia from human iPSCs and cell type‐deconvolved post‐mortem AD brain. APOE ε4 leads to elevated de novo cholesterol synthesis despite the intracellular accumulation of free cholesterol in lysosome and cholesterol ester in lipid droplets coupled with reduced efflux due to impaired lipophagy in iPSC‐derived astrocytes. Lysosomal cholesterol accumulation is found in astrocytes from APOE ε4 human brain. Activation of LXRs and induction of lipophagy ameliorates the lipid phenotypes in APOE ε4 astrocytes. Further, matrisome dysregulation is associated with upregulated chemotaxis, glial activation, and lipid biosynthesis in astrocytes co‐cultured with neurons, which recapitulates altered astrocyte matrisome signaling in human brain.ConclusionThus, human APOE ε4 causes human glia‐specific, cell autonomous and non‐cell autonomous cholesterol and matrisome pathway dysregulation that may increase AD risk.