Lipidomic and transcriptomic profiles provide new insights into the triacylglycerol and glucose handling capacities of the Arctic fox.

The Arctic fox (Vulpes lagopus) is a species indigenous to the Arctic and has developed unique lipid metabolism, but the mechanisms remain unclear. Here, the significantly increased body weight of Arctic foxes was consistent with the significantly increased serum very-low-density lipoprotein (VLDL), and the 40% crude fat diet further increased the Arctic fox body weight. The enhanced body weight gain stems primarily from increased subcutaneous adipose tissue accumulation. The adipose triacylglycerol and phosphatidylethanolamine were significantly greater in Arctic foxes. The adipose fatty-acid synthase content was significantly lower in Arctic foxes, highlighting the main role of exogenous fatty-acids in fat accumulation. Considering the same diet, liver-derived fat dominates adipose expansion in Arctic foxes. Liver transcriptome analysis revealed greater fat and VLDL synthesis in Arctic foxes, consistent with the greater VLDL. Glucose homeostasis wasn't impacted in Arctic foxes. And the free fatty-acids in adipose, which promote insulin resistance, also did not differ between groups. However, the hepatic glycogen was greater in Arctic foxes and transcriptome analysis revealed upregulated glycogen synthesis, improving glucose homeostasis. These results suggest that the superior fat accumulation capacity and distinct characteristics of hepatic and adipose lipid and glucose metabolism facilitate glucose homeostasis and massive fat accumulation in Arctic foxes.

Abnormal metabolism in melanocytes participates in the activation of dendritic cell in halo nevus.

A comprehensive analysis of spatial transcriptomics was carried out to better understand the progress of halo nevus. We found that halo nevus was characterized by overactive immune responses, triggered by chemokines and dendritic cells (DCs), T cells, and macrophages. Consequently, we observed abnormal cell death, such as apoptosis and disulfidptosis in halo nevus, some were closely related to immunity. Interestingly, we identified aberrant metabolites such as uridine diphosphate glucose (UDP-G) within the halo nevus. UDP-G, accompanied by the infiltration of DCs and T cells, exhibited correlations with certain forms of cell death. Subsequent experiments confirmed that UDP-G was increased in vitiligo serum and could activate DCs. We also confirmed that oxidative response is an inducer of UDP-G. In summary, the immune response in halo nevus, including DC activation, was accompanied by abnormal cell death and metabolites. Especially, melanocyte-derived UDP-G may play a crucial role in DC activation.

Nanoarchitectonics and Biological Properties of Nanocomposite Thermosensitive Chitosan Hydrogels Obtained with the Use of Uridine 5'-Monophosphate Disodium Salt.

Currently, an important group of biomaterials used in the research in the field of tissue engineering is thermosensitive chitosan hydrogels. Their main advantage is the possibility of introducing their precursors (sols) into the implantation site using a minimally invasive method-by injection. In this publication, the results of studies on the new chitosan structures in the form of thermosensitive hydrogels containing graphene oxide as a nanofiller are presented. These systems were prepared from chitosan lactate and chitosan chloride solutions with the use of a salt of pyrimidine nucleotide-uridine 5'-monophosphate disodium salt-as the cross-linking agent. In order to perform the characterization of the developed hydrogels, the sol-gel transition temperature of the colloidal systems was first determined based on rheological measurements. The hydrogels were also analyzed using FTIR spectroscopy and SEM. Biological studies assessed the cytotoxicity (resazurin assay) and genotoxicity (alkaline version of the comet assay) of the nanocomposite chitosan hydrogels against normal human BJ fibroblasts. The conducted research allowed us to conclude that the developed hydrogels containing graphene oxide are an attractive material for potential use as scaffolds for the regeneration of damaged tissues.

Preliminary X-ray diffraction and ligand-binding analyses of the N-terminal domain of hypothetical protein Rv1421 from Mycobacterium tuberculosis H37Rv.

Mycobacterium tuberculosis can reside and persist in deep tissues; latent tuberculosis can evade immune detection and has a unique mechanism to convert it into active disease through reactivation. M. tuberculosis Rv1421 (MtRv1421) is a hypothetical protein that has been proposed to be involved in nucleotide binding-related metabolism in cell-growth and cell-division processes. However, due to a lack of structural information, the detailed function of MtRv1421 remains unclear. In this study, a truncated N-terminal domain (NTD) of MtRv1421, which contains a Walker A/B-like motif, was purified and crystallized using PEG 400 as a precipitant. The crystal of MtRv1421-NTD diffracted to a resolution of 1.7 Šand was considered to belong to either the C-centered monoclinic space group C2 or the I-centered orthorhombic space group I222, with unit-cell parameters a = 124.01, b = 58.55, c = 84.87 Å, ß = 133.12° or a = 58.53, b = 84.86, c = 90.52 Å, respectively. The asymmetric units of the C2 or I222 crystals contained two or one monomers, respectively. In terms of the binding ability of MtRv1421-NTD to various ligands, uridine diphosphate (UDP) and UDP-N-acetylglucosamine significantly increased the melting temperature of MtRv1421-NTD, which indicates structural stabilization through the binding of these ligands. Altogether, the results reveal that a UDP moiety may be required for the interaction of MtRv1421-NTD as a nucleotide-binding protein with its ligand.

Anti-Inflammatory Responses Produced with Nippostrongylus brasiliensis-Derived Uridine via the Mitochondrial ATP-Sensitive Potassium Channel and Its Anti-Atherosclerosis Effect in an Apolipoprotein E Gene Knockout Mouse Model.

Atherosclerosis (AS) has become the leading cause of cardiovascular disease worldwide. Our previous study had observed that Nippostrongylus brasiliensis (Nb) infection or its derived products could inhibit AS development by inducing an anti-inflammatory response. We performed a metabolic analysis to screen Nb-derived metabolites with anti-inflammation activity and evaluated the AS-prevention effect. We observed that the metabolite uridine had higher expression levels in mice infected with the Nb and ES (excretory-secretory) products and could be selected as a key metabolite. ES and uridine interventions could reduce the pro-inflammatory responses and increase the anti-inflammatory responses in vitro and in vivo. The apolipoprotein E gene knockout (ApoE-/-) mice were fed with a high-fat diet for the AS modeling. Following the in vivo intervention, ES products or uridine significantly reduced serum and liver lipid levels, alleviated the formation of atherosclerosis, and reduced the pro-inflammatory responses in serum or plaques, while the anti-inflammatory responses showed opposite trends. After blocking with 5-HD (5-hydroxydecanoate sodium) in vitro, the mRNA levels of M2 markers were significantly reduced. When blocked with 5-HD in vivo, the degree of atherosclerosis was worsened, the pro-inflammatory responses were increased compared to the uridine group, while the anti-inflammatory responses decreased accordingly. Uridine, a key metabolite from Nippostrongylus brasiliensis, showed anti-inflammatory and anti-atherosclerotic effects in vitro and in vivo, which depend on the activation of the mitochondrial ATP-sensitive potassium channel.

Glycolytic PFKFB3 and Glycogenic UGP2 Axis Regulates Perfusion Recovery in Experimental Hind Limb Ischemia.

BACKGROUND: Despite being in an oxygen-rich environment, endothelial cells (ECs) use anaerobic glycolysis (Warburg effect) as the primary metabolic pathway for cellular energy needs. PFKFB (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase)-3 regulates a critical enzymatic checkpoint in glycolysis and has been shown to induce angiogenesis. This study builds on our efforts to determine the metabolic regulation of ischemic angiogenesis and perfusion recovery in the ischemic muscle. METHODS: Hypoxia serum starvation (HSS) was used as an in vitro peripheral artery disease (PAD) model, and hind limb ischemia by femoral artery ligation and resection was used as a preclinical PAD model. RESULTS: Despite increasing PFKFB3-dependent glycolysis, HSS significantly decreased the angiogenic capacity of ischemic ECs. Interestingly, inhibiting PFKFB3 significantly induced the angiogenic capacity of HSS-ECs. Since ischemia induced a significant in PFKFB3 levels in hind limb ischemia muscle versus nonischemic, we wanted to determine whether glucose bioavailability (rather than PFKFB3 expression) in the ischemic muscle is a limiting factor behind impaired angiogenesis. However, treating the ischemic muscle with intramuscular delivery of D-glucose or L-glucose (osmolar control) showed no significant differences in the perfusion recovery, indicating that glucose bioavailability is not a limiting factor to induce ischemic angiogenesis in experimental PAD. Unexpectedly, we found that shRNA-mediated PFKFB3 inhibition in the ischemic muscle resulted in a numerical increase in perfusion recovery and significantly higher vascular density compared with control shRNA (consistent with the increased angiogenic capacity of PFKFB3 silenced HSS-ECs). Based on these data, we hypothesized that inhibiting HSS-induced PFKFB3 in ischemic ECs activates alternative metabolic pathways that revascularize the ischemic muscle in experimental PAD. A comprehensive glucose metabolic gene qPCR arrays in PFKFB3 silenced HSS-ECs, and PFKFB3-inhibited ischemic muscle versus respective controls identified UGP2 (uridine diphosphate-glucose pyrophosphorylase 2), a regulator of protein glycosylation and glycogen synthesis, is induced upon PFKFB3 inhibition in vitro and in vivo. Antibody-mediated inhibition of UGP2 in the ischemic muscle significantly impaired perfusion recovery versus IgG control. Mechanistically, supplementing uridine diphosphate-glucose, a metabolite of UGP2 activity, significantly induced HSS-EC angiogenic capacity in vitro and enhanced perfusion recovery in vivo by increasing protein glycosylation (but not glycogen synthesis). CONCLUSIONS: Our data present that inhibition of maladaptive PFKFB3-driven glycolysis in HSS-ECs is necessary to promote the UGP2-uridine diphosphate-glucose axis that enhances ischemic angiogenesis and perfusion recovery in experimental PAD.

Advances in Engineering Nucleotide Sugar Metabolism for Natural Product Glycosylation in Saccharomyces cerevisiae.

Glycosylation is a ubiquitous modification present across all of biology, affecting many things such as physicochemical properties, cellular recognition, subcellular localization, and immunogenicity. Nucleotide sugars are important precursors needed to study glycosylation and produce glycosylated products. Saccharomyces cerevisiae is a potentially powerful platform for producing glycosylated biomolecules, but it lacks nucleotide sugar diversity. Nucleotide sugar metabolism is complex, and understanding how to engineer it will be necessary to both access and study heterologous glycosylations found across biology. This review overviews the potential challenges with engineering nucleotide sugar metabolism in yeast from the salvage pathways that convert free sugars to their associated UDP-sugars to de novo synthesis where nucleotide sugars are interconverted through a complex metabolic network with governing feedback mechanisms. Finally, recent examples of engineering complex glycosylation of small molecules in S. cerevisiae are explored and assessed.

Triclosan administration to humanized UDP-glucuronosyltransferase 1 neonatal mice induces UGT1A1 through a dependence on PPARα and ATF4.

Triclosan (TCS) is an antimicrobial toxicant found in a myriad of consumer products and has been detected in human tissues, including breastmilk. We have evaluated the impact of lactational TCS on UDP-glucuronosyltransferase 1A1 (UGT1A1) expression and bilirubin metabolism in humanized UGT1 (hUGT1) neonatal mice. In hUGT1 mice, expression of the hepatic UGT1A1 gene is developmentally delayed resulting in elevated total serum bilirubin (TSB) levels. We found that newborn hUGT1 mice breastfed or orally treated with TCS presented lower TSB levels along with induction of hepatic UGT1A1. Lactational and oral treatment by gavage with TCS leads to the activation of hepatic nuclear receptors constitutive androstane receptor (CAR), peroxisome proliferator-activated receptor alpha (PPARα), and stress sensor, activating transcription factor 4 (ATF4). When CAR-deficient hUGT1 mice (hUGT1/Car-/-) were treated with TCS, TSB levels were reduced with a robust induction of hepatic UGT1A1, leaving us to conclude that CAR is not tied to UGT1A1 induction. Alternatively, when PPARα-deficient hUGT1 mice (hUGT1/Pparα-/-) were treated with TCS, hepatic UGT1A1 was not induced. Additionally, we had previously demonstrated that TCS is a potent inducer of ATF4, a transcriptional factor linked to the integrated stress response. When ATF4 was deleted in liver of hUGT1 mice (hUGT1/Atf4ΔHep) and these mice treated with TCS, we observed superinduction of hepatic UGT1A1. Oxidative stress genes in livers of hUGT1/Atf4ΔHep treated with TCS were increased, suggesting that ATF4 protects liver from excessive oxidative stress. The increase oxidative stress may be associated with superinduction of UGT1A1. The expression of ATF4 in neonatal hUGT1 hepatic tissue may play a role in the developmental repression of UGT1A1.

Long non-coding RNA HOTAIR: from pan-cancer analysis to colorectal cancer-related uridine metabolism.

Long non-coding RNAs (lncRNAs) are involved significantly in the development of human cancers. lncRNA HOTAIR has been reported to play an oncogenic role in many human cancers. Its specific regulatory role is still elusive. And it might have enormous potential to interpret the malignant progression of tumors in a broader perspective, that is, in pan-cancer. We comprehensively investigated the effect of HOTAIR expression on tumor prognosis across human malignancies by analyzing multiple cancer-related databases like The Cancer Genome Atlas (TCGA) and Tumor Immune Estimation Resource (TIMER). Bioinformatics data indicated that HOTAIR was overexpressed in most of these human malignancies and was significantly associated with the prognosis of patients with cancer, especially in colorectal cancer (CRC). Subsequently, this study further clarified the utility of HOTAIR that downregulation of its expression could result in reduced proliferation and invasion of CRC cells. Mechanistically, HOTAIR upregulated the metabolic enzymes UPP1 by recruiting histone methyltransferase EZH2, thereby increasing the tumor progression. Our results highlight the essential role of HOTAIR in pan-cancer and uridine bypass, suggesting that the HOTAIR/EZH2/UPP1 axis might be a novel target for overcoming CRC. We anticipate that the role of HOTAIR in metabolism could be important in the context of CRC and even exploited for therapeutic purposes.

A Case of Crigler-Najjar Syndrome Type II During Pregnancy and Its Management.

Crigler-Najjar syndrome (CNS) is a genetic syndrome that results in increased levels of unconjugated bilirubin due to less or completely nonfunctional enzyme, uridine diphosphoglucoronyltransferase (UDPGT) in hepatocytes. When bilirubin metabolism is compromised, hyperbilirubinemia is caused, which results in increased levels of unconjugated and conjugated bilirubin in the bloodstream. CNS is an autosomal recessive disorder, usually noticeable as people get older. This disorder is divided into two types: CNS type I and CNS type II, which are caused by homozygous or compound heterozygous mutations in the UDP glucuronosyltransferase family 1 member A1 (UGT1A1) gene. The disorder affects all races and genders equally, with a prevalence of one per million births. CNS type I is more severe and has almost undetectable UDPGT expression activity, and affected individuals die before one year of age. Consanguineous marriages are a major risk factor as CNS is inherited in an autosomal recessive manner. Being rare, maternal CNS type II is yet to be completely understood in terms of its impact on the mother, her pregnancy, and the infant. We aim to present a case of a pregnant female with CNS type II and its clinical course. She was monitored closely during her pregnancy. The treatment protocol was followed as per previously reported cases and was managed on low, non-teratogenic doses of phenobarbitone. A successful outcome with the birth of a healthy infant having normal neurological development till six months follow-up was observed.

Exploring the physicochemical properties of the integration of Tristearoyl uridine in Langmuir monolayers: An approach to cell membrane modeling for prodrugs.

Understanding the mechanisms by which drugs interact with cell membranes is crucial for unraveling the underlying biochemical and biophysical processes that occur on the surface of these membranes. Our research focused on studying the interaction between an ester-type derivative of tristearoyl uridine and model cell membranes composed of lipid monolayers at the air-water interface. For that, we selected a specific lipid to simulate nontumorigenic cell membranes, namely 1,2-dihexadecanoyl-sn-glycero-3-phospho-l-serine. We noted significant changes in the surface pressure-area isotherms, with a noticeable shift towards larger areas, which was lower than expected for ideal mixtures, indicating monolayer condensation. Furthermore, the viscoelastic properties of the interfacial film demonstrated an increase in both the elastic and viscous parameters for the mixed film. We also observed structural alterations using vibrational spectroscopy, which revealed an increase in the all-trans to gauche conformers ratio. This confirmed the stiffening effect of the prodrug on the lipid monolayer. In summary, this study indicates that this lipophilic prodrug significantly impacts the lipid monolayer's thermodynamic, rheological, electrical, and molecular characteristics. This information is crucial for understanding how the drug interacts with specific sites on the cellular membrane. It also has implications for drug delivery, as the drug's passage into the cytosol may involve traversing the lipid bilayer.

A Basic Method for Formulating mRNA-Lipid Nanoparticle Vaccines in the Lab.

During recent years, RNA therapeutics have begun to make a substantial impact in the clinic, with the approval of the siRNA-based therapeutic Patisiran in 2018, and of the two mRNA SARS-CoV-2 vaccines, BNT162b2 and mRNA-1273 in 2021. A key to the success of these therapeutics lies in the lipid-based delivery system. The therapeutic RNAs are encapsulated in lipid nanoparticles (LNPs), which protect against enzymatic degradation and efficiently deliver the RNA across the cell membrane into the cytosol. Thereby, the method used for LNP synthesis and its lipid composition are crucial aspects that decide the efficacy of the LNP-RNA hetero system. Here we provide a detailed guide for the simple preparation of LNP-encapsulated mRNA vaccines.

Risk Factors for Adverse Events of Nanoliposomal Irinotecan Plus 5-Fluorouracil and L-leucovorin.

Background/Aim: The regimen with nanoliposomal irinotecan plus 5-fluorouracil and L-leucovorin (nal-IRI/FL) is used for metastatic pancreatic cancer. A clinical study has indicated that the uridine diphosphate-glucuronosyltransferase (UGT) 1A1 polymorphism is associated with neutropenia during nal-IRI/FL treatment; however, no studies have reported risk factors for the occurrence of adverse events in the clinical setting. This study aimed to explore the risk factors for adverse events of nal-IRI/FL. Patients and Methods: This study included patients with metastatic pancreatic cancer who started nal-IRI/FL treatment. Patient information, including laboratory data before nal-IRI/FL initiation and adverse events during nal-IRI/FL treatment, was retrospectively obtained from medical records. Results: This study consisted of 36 patients, including 16, 16, and 4 with UGT1A1*6 or *28 wild-type (-/-), heterozygous (+/-), and homozygous (+/+), respectively. Patients with UGT1A1*6 or *28 (+/+) exhibited significantly lower nadir counts of white blood cells (p=0.033) and neutrophils (p=0.043). Multiple regression analyses revealed that the decreased white blood cell count was significantly associated with the genotype of UGT1A1*6 or *28 (+/+) (p=0.009), high aspartate aminotransferase (AST) value before the therapy (p=0.019), and pancreatic head cancer (p=0.030). Also, the decreased neutrophil count was significantly related to the genotype of UGT1A1*6 or *28 (+/+) (p=0.017). Conclusion: Patients with UGT1A1*6 or *28 (+/+) should be especially concerned about neutropenia and leukopenia during nal-IRI/FL treatment. Additionally, high AST value and pancreatic head cancer may be risk factors for leukopenia during nal-IRI/FL treatment.

Construction of a New Agrobacterium tumefaciens-Mediated Transformation System based on a Dual Auxotrophic Approach in Cordyceps militaris.

Cordyceps militaris is a significant edible fungus that produces a variety of bioactive compounds. We have previously established a uridine/uracil auxotrophic mutant and a corresponding Agrobacterium tumefaciens-mediated transformation (ATMT) system for genetic characterization in C. militaris using pyrG as a screening marker. In this study, we constructed an ATMT system based on a dual pyrG and hisB auxotrophic mutant of C. militaris. Using the uridine/uracil auxotrophic mutant as the background and pyrG as a selection marker, the hisB gene encoding imidazole glycerophosphate dehydratase, required for histidine biosynthesis, was knocked out by homologous recombination to construct a histidine auxotrophic C. militaris mutant. Then, pyrG in the histidine auxotrophic mutant was deleted to construct a ΔpyrG ΔhisB dual auxotrophic mutant. Further, we established an ATMT transformation system based on the dual auxotrophic C. militaris by using GFP and DsRed as reporter genes. Finally, to demonstrate the application of this dual transformation system for studies of gene function, knock out and complementation of the photoreceptor gene CmWC-1 in the dual auxotrophic C. militaris were performed. The newly constructed ATMT system with histidine and uridine/uracil auxotrophic markers provides a promising tool for genetic modifications in the medicinal fungus C. militaris.

Ngk1 kinase-mediated N-acetylglucosamine metabolism promotes UDP-GlcNAc biosynthesis in Saccharomyces cerevisiae.

N-acetylglucosamine (GlcNAc) is an important structural component of the cell wall chitin, N-glycans, glycolipids, and GPI-anchors in eukaryotes. GlcNAc kinase phosphorylates GlcNAc into GlcNAc-6-phosphate, a precursor of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that serves as a substrate for glycan synthesis. Although GlcNAc kinase is found widely in organisms ranging from microorganisms to mammals, it has never been found in the model yeast Saccharomyces cerevisiae. Here, we demonstrate the presence of GlcNAc metabolism for UDP-GlcNAc biosynthesis in S. cerevisiae through Ngk1, a GlcNAc kinase we discovered previously. The overexpression or deletion of Ngk1 in the presence of GlcNAc affected the amount of both UDP-GlcNAc and chitin, suggesting that GlcNAc metabolism via Ngk1 promotes UDP-GlcNAc synthesis. Our data suggest that the Ngk1-mediated GlcNAc metabolism compensates for the hexosamine pathway, a known pathway for UDP-GlcNAc synthesis.

The predictive value of plasma uridine for type 2 diabetes and its atherosclerotic complications.

Objective: Uridine might be a common link between pathological pathways in diabetes and cardiovascular diseases. This study aimed to investigate the predictive value of plasma uridine for type 2 diabetes (T2D) and T2D with atherosclerosis. Methods: Individuals with T2D and healthy controls (n = 218) were randomly enrolled in a cross-sectional study. Patients with T2D were divided into two groups based on carotid ultrasound: patients with carotid atherosclerosis (CA) (group DCA) and patients without CA (group D). Plasma uridine was determined using HPLC-MS/MS. Correlation and logistic regression analyses were used to analyze the results. Results: Fasting and postprandial uridine were significantly increased in patients with T2D compared with healthy individuals. Logistic regression suggested that fasting and postprandial uridine were independent risk factors for T2D. The receiver operating characteristic (ROC) curve showed that fasting uridine had a predictive value on T2D (95% CI, 0.686-0.863, sensitivity 74.3%, specificity 71.8%). Fasting uridine was positively correlated with LDL-c, FBG, and PBG and negatively correlated with fasting C-peptide (CP-0h) and HOMA-IS. The change in postprandial uridine from fasting baseline (Δuridine) was smaller in T2D patients with CA compared with those without (0.80 (0.04-2.46) vs 2.01 (0.49-3.15), P = 0.010). Δuridine was also associated with T2D with CA and negatively correlated with BMI, CP-0h, and HOMA-IR. Conclusion: Fasting uridine has potential as a predictor of diabetes. Δuridine is closely associated with carotid atherosclerosis in patients with T2D.

Purinergic Signalling Mediates Aberrant Excitability of Developing Neuronal Circuits in the Fmr1 Knockout Mouse Model.

Neuronal hyperexcitability within developing cortical circuits is a common characteristic of several heritable neurodevelopmental disorders, including Fragile X Syndrome (FXS), intellectual disability and autism spectrum disorders (ASD). While this aberrant circuitry is typically studied from a neuron-centric perspective, glial cells secrete soluble factors that regulate both neurite extension and synaptogenesis during development. The nucleotide-mediated purinergic signalling system is particularly instrumental in facilitating these effects. We recently reported that within a FXS animal model, the Fmr1 KO mouse, the purinergic signalling system is upregulated in cortical astrocytes leading to altered secretion of synaptogenic and plasticity-related proteins. In this study, we examined whether elevated astrocyte purinergic signalling also impacts neuronal morphology and connectivity of Fmr1 KO cortical neurons. Here, we found that conditioned media from primary Fmr1 KO astrocytes was sufficient to enhance neurite extension and complexity of both wildtype and Fmr1 KO neurons to a similar degree as UTP-mediated outgrowth. Significantly enhanced firing was also observed in Fmr1 KO neuron-astrocyte co-cultures grown on microelectrode arrays but was associated with large deficits in firing synchrony. The selective P2Y2 purinergic receptor antagonist AR-C 118925XX effectively normalized much of the aberrant Fmr1 KO activity, designating P2Y2 as a potential therapeutic target in FXS. These results not only demonstrate the importance of astrocyte soluble factors in the development of neural circuitry, but also show that P2Y purinergic receptors play a distinct role in pathological FXS neuronal activity.

Uridine diphosphate glucuronosyltransferase 1A1 prevents the progression of liver injury.

BACKGROUND: Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) plays a crucial role in metabolizing and detoxifying endogenous and exogenous substances. However, its contribution to the progression of liver damage remains unclear. AIM: To determine the role and mechanism of UGT1A1 in liver damage progression. METHODS: We investigated the relationship between UGT1A1 expression and liver injury through clinical research. Additionally, the impact and mechanism of UGT1A1 on the progression of liver injury was analyzed through a mouse model study. RESULTS: Patients with UGT1A1 gene mutations showed varying degrees of liver damage, while patients with acute-on-chronic liver failure (ACLF) exhibited relatively reduced levels of UGT1A1 protein in the liver as compared to patients with chronic hepatitis. This suggests that low UGT1A1 levels may be associated with the progression of liver damage. In mouse models of liver injury induced by carbon tetrachloride (CCl4) and concanavalin A (ConA), the hepatic levels of UGT1A1 protein were found to be increased. In mice with lipopolysaccharide or liver steatosis-mediated liver-injury progression, the hepatic protein levels of UGT1A1 were decreased, which is consistent with the observations in patients with ACLF. UGT1A1 knockout exacerbated CCl4- and ConA-induced liver injury, hepatocyte apoptosis and necroptosis in mice, intensified hepatocyte endoplasmic reticulum (ER) stress and oxidative stress, and disrupted lipid metabolism. CONCLUSION: UGT1A1 is upregulated as a compensatory response during liver injury, and interference with this upregulation process may worsen liver injury. UGT1A1 reduces ER stress, oxidative stress, and lipid metabolism disorder, thereby mitigating hepatocyte apoptosis and necroptosis.

[Identification and expression of genome of uridine diphosphate glycosyltransferase (UGT) gene family from Chrysanthemum indicum].

Uridine diphosphate glycosyltransferase(UGT) is involved in the glycosylation of a variety of secondary metabolites in plants and plays an important role in plant growth and development and regulation of secondary metabolism. Based on the genome of a diploid Chrysanthemum indicum, the UGT gene family from Ch. indicum was identified by bioinformatics methods, and the physical and chemical properties, subcellular localization prediction, conserved motif, phylogeny, chromosome location, gene structure, and gene replication events of UGT protein were analyzed. Transcriptome and real-time fluorescence quantitative polymerase chain reaction(PCR) were used to analyze the expression pattern of the UGT gene in flowers and leaves of Ch. indicum. Quasi-targeted metabolomics was used to analyze the differential metabolites in flowers and leaves. The results showed that a total of 279 UGT genes were identified in the Ch. indicum genome. Phylogenetic analysis showed that these UGT genes were divided into 8 subfamilies. Members of the same subfamily were distributed in clusters on the chromosomes. Tandem duplications were the main driver of the expansion of the UGT gene family from Ch. indicum. Structural domain analysis showed that 262 UGT genes had complete plant secondary metabolism signal sequences(PSPG box). The analysis of cis-acting elements indicated that light-responsive elements were the most ubiquitous elements in the promoter regions of UGT gene family members. Quasi-targeted metabolome analysis of floral and leaf tissue revealed that most of the flavonoid metabolites, including luteolin-7-O-glucoside and kaempferol-7-O-glucoside, had higher accumulation in flowers. Comparative transcriptome analysis of flower and leaf tissue showed that there were 72 differentially expressed UGT genes, of which 29 genes were up-regulated in flowers, and 43 genes were up-regulated in leaves. Correlation network and phylogenetic analysis showed that CindChr9G00614970.1, CindChr2G00092510.1, and CindChr2G00092490.1 may be involved in the synthesis of 7-O-flavonoid glycosides in Ch. indicum, and real-time fluorescence quantitative PCR analysis further confirmed the reliability of transcriptome data. The results of this study are helpful to understand the function of the UGT gene family from Ch. indicum and provide data reference and theoretical basis for further study on the molecular regulation mechanism of flavonoid glycosides synthesis in Ch. indicum.

Engineered Saccharomyces cerevisiae as a Biosynthetic Platform of Nucleotide Sugars.

Glycosylation of biomolecules can greatly alter their physicochemical properties, cellular recognition, subcellular localization, and immunogenicity. Glycosylation reactions rely on the stepwise addition of sugars using nucleotide diphosphate (NDP)-sugars. Making these substrates readily available will greatly accelerate the characterization of new glycosylation reactions, elucidation of their underlying regulation mechanisms, and production of glycosylated molecules. In this work, we engineered Saccharomyces cerevisiae to heterologously express nucleotide sugar synthases to access a wide variety of uridine diphosphate (UDP)-sugars from simple starting materials (i.e., glucose and galactose). Specifically, activated glucose, uridine diphosphate d-glucose (UDP-d-Glc), can be converted to UDP-d-glucuronic acid (UDP-d-GlcA), UDP-d-xylose (UDP-d-Xyl), UDP-d-apiose (UDP-d-Api), UDP-d-fucose (UDP-d-Fuc), UDP-l-rhamnose (UDP-l-Rha), UDP-l-arabinopyranose (UDP-l-Arap), and UDP-l-arabinofuranose (UDP-l-Araf) using the corresponding nucleotide sugar synthases of plant and microbial origins. We also expressed genes encoding the salvage pathway to directly activate free sugars to achieve the biosynthesis of UDP-l-Arap and UDP-l-Araf. We observed strong inhibition of UDP-d-Glc 6-dehydrogenase (UGD) by the downstream product UDP-d-Xyl, which we circumvented using an induction system (Tet-On) to delay the production of UDP-d-Xyl to maintain the upstream UDP-sugar pool. Finally, we performed a time-course study using strains containing the biosynthetic pathways to produce five non-native UDP-sugars to elucidate their time-dependent interconversion and the role of UDP-d-Xyl in regulating UDP-sugar metabolism. These engineered yeast strains are a robust platform to (i) functionally characterize sugar synthases in vivo, (ii) biosynthesize a diverse selection of UDP-sugars, (iii) examine the regulation of intracellular UDP-sugar interconversions, and (iv) produce glycosylated secondary metabolites and proteins.