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Hepatology Communications May 2024Human genetic studies have identified several mitochondrial amidoxime-reducing component 1 (MTARC1) variants as protective against metabolic dysfunction-associated...
BACKGROUND
Human genetic studies have identified several mitochondrial amidoxime-reducing component 1 (MTARC1) variants as protective against metabolic dysfunction-associated steatotic liver disease. The MTARC1 variants are associated with decreased plasma lipids and liver enzymes and reduced liver-related mortality. However, the role of mARC1 in fatty liver disease is still unclear.
METHODS
Given that mARC1 is mainly expressed in hepatocytes, we developed an N-acetylgalactosamine-conjugated mouse Mtarc1 siRNA, applying it in multiple in vivo models to investigate the role of mARC1 using multiomic techniques.
RESULTS
In ob/ob mice, knockdown of Mtarc1 in mouse hepatocytes resulted in decreased serum liver enzymes, LDL-cholesterol, and liver triglycerides. Reduction of mARC1 also reduced liver weight, improved lipid profiles, and attenuated liver pathological changes in 2 diet-induced metabolic dysfunction-associated steatohepatitis mouse models. A comprehensive analysis of mARC1-deficient liver from a metabolic dysfunction-associated steatohepatitis mouse model by metabolomics, proteomics, and lipidomics showed that Mtarc1 knockdown partially restored metabolites and lipids altered by diet.
CONCLUSIONS
Taken together, reducing mARC1 expression in hepatocytes protects against metabolic dysfunction-associated steatohepatitis in multiple murine models, suggesting a potential therapeutic approach for this chronic liver disease.
Topics: Animals; Mice; Disease Models, Animal; Hepatocytes; Gene Knockdown Techniques; Liver; Male; RNA, Small Interfering; Mitochondrial Proteins; Non-alcoholic Fatty Liver Disease; Mice, Inbred C57BL
PubMed: 38696369
DOI: 10.1097/HC9.0000000000000419 -
Microorganisms Apr 2024contributes to frequent, persistent, and, often, polymicrobial respiratory tract infections for individuals with cystic fibrosis (CF). Chronic CF infections lead to...
contributes to frequent, persistent, and, often, polymicrobial respiratory tract infections for individuals with cystic fibrosis (CF). Chronic CF infections lead to bronchiectasis and a shortened lifespan. expresses numerous adhesins, including lectins known to bind the epithelial cell and mucin glycoconjugates. Blocking carbohydrate-mediated host-pathogen and intra-biofilm interactions critical to the initiation and perpetuation of colonization offer promise as anti-infective treatment strategies. To inform anti-adhesion therapies, we profiled the monosaccharide binding of from CF and non-CF sources, and assessed whether specific bacterial phenotypic characteristics affected carbohydrate-binding patterns. Focusing at the cellular level, microscopic and spectrofluorometric tools permitted the solution-phase analysis of binding to a panel of fluorescent glycopolymers possessing distinct pendant monosaccharides. All demonstrated significant binding to glycopolymers specific for α-D-galactose, β-D--acetylgalactosamine, and β-D-galactose-3-sulfate. In each culture, a small subpopulation accounted for the binding. The carbohydrate anomeric configuration and sulfate ester presence markedly influenced binding. While this opportunistic pathogen from CF hosts presented with various colony morphologies and physiological activities, no phenotypic, physiological, or structural feature predicted enhanced or diminished monosaccharide binding. Important to anti-adhesive therapeutic strategies, these findings suggest that, regardless of phenotype or clinical source, maintain a small subpopulation that may readily associate with specific configurations of specific monosaccharides. This report provides insights into whole-cell carbohydrate-binding profiles and into the context within which successful anti-adhesive and/or anti-virulence anti-infective agents for CF must contend.
PubMed: 38674745
DOI: 10.3390/microorganisms12040801 -
Marine Drugs Apr 2024Fucosylated chondroitin sulfate is a unique glycosaminoglycan isolated from sea cucumbers, with excellent anticoagulant activity. The fucosyl branch in FCS is generally...
Fucosylated chondroitin sulfate is a unique glycosaminoglycan isolated from sea cucumbers, with excellent anticoagulant activity. The fucosyl branch in FCS is generally located at the 3-OH of -glucuronic acid but, recently, a novel structure with α--fucose linked to the 6-OH of -acetyl-galactosamine has been found. Here, using functionalized monosaccharide building blocks, we prepared novel FCS tetrasaccharides with fucosyl branches both at the 6-OH of GalNAc and 3-OH of GlcA. In the synthesis, the protective group strategy of selective -sulfation, as well as stereoselective glycosylation, was established, which enabled the efficient synthesis of the specific tetrasaccharide compounds. This research enriches knowledge on the structural types of FCS oligosaccharides and facilitates the exploration of the structure-activity relationship in the future.
Topics: Chondroitin Sulfates; Animals; Oligosaccharides; Sea Cucumbers; Glycosylation; Fucose; Anticoagulants; Structure-Activity Relationship; Acetylgalactosamine
PubMed: 38667801
DOI: 10.3390/md22040184 -
Angewandte Chemie (International Ed. in... Jun 2024Nucleic acids in the form of siRNA, antisense oligonucleotides or mRNA are currently explored as new promising modalities in the pharmaceutical industry. Particularly,...
Nucleic acids in the form of siRNA, antisense oligonucleotides or mRNA are currently explored as new promising modalities in the pharmaceutical industry. Particularly, the success of mRNA-vaccines against SARS-CoV-2, along with the successful development of the first sugar-modified siRNA therapeutics has inspired the field. The development of nucleic acid therapeutics requires efficient chemistry to link oligonucleotides to chemical structures that can improve stability, boost cellular uptake, or enable specific targeting. For the siRNA therapeutics currently in use, modification of the 3'-end of the oligonucleotides with triple-N-acetylgalactosamine (GalNAc) was shown to be of significance. This modification is currently achieved through cumbersome multistep synthesis and subsequent loading onto the solid support material. Herein, we report the development of a bifunctional click-reactive linker that allows the modification of oligonucleotides in a tandem click reaction with multiple sugars, regardless of the position within the oligonucleotide, with remarkable efficiency and in a one-pot reaction.
Topics: Click Chemistry; Copper; Oligonucleotides; Catalysis; Acetylgalactosamine; SARS-CoV-2; RNA, Small Interfering
PubMed: 38606873
DOI: 10.1002/anie.202405161 -
Glycobiology Apr 2024Aging affects tissue glycan profiles, which may alter cellular functions and increase the risk of age-related diseases. Glycans are biosynthesized by...
Aging affects tissue glycan profiles, which may alter cellular functions and increase the risk of age-related diseases. Glycans are biosynthesized by glycosyltransferases using the corresponding nucleotide sugar, and the availability of nucleotide sugars affects glycosylation efficiency. However, the effects of aging on nucleotide sugar profiles and contents are yet to be elucidated. Therefore, this study aimed to investigate the effects of aging on nucleotide sugars using a new LC-MS/MS method. Specifically, the new method was used to determine the nucleotide sugar contents of various tissues (brain, liver, heart, skeletal muscle, kidney, lung, and colon) of male C57BL/6NCr mice (7- or 26-month-old). Characteristic age-associated nucleotide sugar changes were observed in each tissue sample. Particularly, there was a significant decrease in UDP-glucuronic acid content in the kidney of aged mice and a decrease in the contents of several nucleotide sugars, including UDP-N-acetylgalactosamine, in the brain of aged mice. Additionally, there were variations in nucleotide sugar profiles among the tissues examined regardless of the age. The kidneys had the highest concentration of UDP-glucuronic acid among the seven tissues. In contrast, the skeletal muscle had the lowest concentration of total nucleotide sugars among the tissues; however, CMP-N-acetylneuraminic acid and CDP-ribitol were relatively enriched. Conclusively, these findings may contribute to the understanding of the roles of glycans in tissue aging.
Topics: Animals; Mice; Male; Aging; Mice, Inbred C57BL; Nucleotides; Kidney; Muscle, Skeletal; Tandem Mass Spectrometry; Liver; Brain
PubMed: 38598324
DOI: 10.1093/glycob/cwae032 -
The AAPS Journal Apr 2024Small interfering RNA (siRNA) is gaining momentum as a therapeutic modality with six approved products. Since siRNA has the potential to elicit undesired immune...
Small interfering RNA (siRNA) is gaining momentum as a therapeutic modality with six approved products. Since siRNA has the potential to elicit undesired immune responses in patients, immunogenicity assessment is required during clinical development by regulatory authorities. In this study, anti-siRNA polyclonal antibodies were generated through animal immunization. These cross-reactive polyclonal antibodies recognized mostly the N-acetylgalactosamine (GalNAc) moiety with a small fraction against sequence-independent epitopes. We demonstrate that the polyclonal antibodies can be utilized as immunogenicity assay positive controls for the same class of GalNAc-conjugated siRNAs. In addition, anti-GalNAc mAbs showed desired sensitivity and drug tolerance, supporting their use as alternative surrogate positive controls. These findings can guide positive control selection and immunogenicity assay development for GalNAc-conjugated siRNAs and other oligonucleotide therapeutics.
Topics: Animals; Humans; RNA, Small Interfering; Acetylgalactosamine; Oligonucleotides; Antibodies, Monoclonal
PubMed: 38570436
DOI: 10.1208/s12248-024-00914-w -
International Journal of Biological... May 2024Glycosaminoglycan (GAG) lyases are important tools for investigating the structure of GAGs and preparing low-molecular-weight GAGs. The PL35 family, a recently...
Glycosaminoglycan (GAG) lyases are important tools for investigating the structure of GAGs and preparing low-molecular-weight GAGs. The PL35 family, a recently established polysaccharide lyase family, should be further investigated. In this study, we discovered a new GAG lyase, CHa1, which belongs to the PL35 family. When expressed heterologously in Escherichia coli (BL21), CHa1 exhibited high expression levels and solubility. The optimal activity was observed in Tris-HCl buffer (pH 7.0) or sodium phosphate buffer (pH 8.0) at 30 °C. The specific activities towards HA, CSA, CSC, CSD, CSE, and HS were 3.81, 13.03, 36.47, 18.46, 6.46, and 0.50 U/mg protein, respectively. CHa1 digests substrate chains randomly that acting as an endolytic lyase and shows a significant preference for GlcA-containing structures, prefers larger oligosaccharides (≥UDP8) and can generate a series of oligosaccharides composed mainly of the A unit when digesting CSA. These oligosaccharides include ΔC-A, ΔC-A-A, ΔC-A-A-A, ΔC-A-A-A-A, and ΔC-A-A-A-A-A. The residues Tyr and His play crucial roles in the catalytic process, and Ser, Asn, Asn, Trp, Gln, Lys, Arg and Gln may participate in the binding process of CHa1. This study on CHa1 contributes to our understanding of the PL35 family and provides valuable tools for investigating the structure of GAGs.
Topics: Polysaccharide-Lyases; Substrate Specificity; Acetylgalactosamine; Escherichia coli; Glycosaminoglycans; Amino Acid Sequence; Oligosaccharides
PubMed: 38561119
DOI: 10.1016/j.ijbiomac.2024.131283 -
Cell Metabolism May 2024Metabolic dysfunction-associated fatty liver disease (MAFLD) has a global prevalence of about 25% and no approved therapy. Using metabolomic and proteomic analyses, we...
Metabolic dysfunction-associated fatty liver disease (MAFLD) has a global prevalence of about 25% and no approved therapy. Using metabolomic and proteomic analyses, we identified high expression of hepatic transketolase (TKT), a metabolic enzyme of the pentose phosphate pathway, in human and mouse MAFLD. Hyperinsulinemia promoted TKT expression through the insulin receptor-CCAAT/enhancer-binding protein alpha axis. Utilizing liver-specific TKT overexpression and knockout mouse models, we demonstrated that TKT was sufficient and required for MAFLD progression. Further metabolic flux analysis revealed that Tkt deletion increased hepatic inosine levels to activate the protein kinase A-cAMP response element binding protein cascade, promote phosphatidylcholine synthesis, and improve mitochondrial function. Moreover, insulin induced hepatic TKT to limit inosine-dependent mitochondrial activity. Importantly, N-acetylgalactosamine (GalNAc)-siRNA conjugates targeting hepatic TKT showed promising therapeutic effects on mouse MAFLD. Our study uncovers how hyperinsulinemia regulates TKT-orchestrated inosine metabolism and mitochondrial function and provides a novel therapeutic strategy for MAFLD prevention and treatment.
Topics: Animals; Female; Humans; Male; Mice; Hyperinsulinism; Inosine; Liver; Mice, Inbred C57BL; Mice, Knockout; Mitochondria; Transketolase
PubMed: 38547864
DOI: 10.1016/j.cmet.2024.03.003 -
International Journal of Molecular... Mar 2024Mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome) is a rare autosomal recessive lysosomal storage disease (LSD) caused by deficiency of a hydrolase enzyme,...
Mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome) is a rare autosomal recessive lysosomal storage disease (LSD) caused by deficiency of a hydrolase enzyme, N-acetylgalactosamine-6-sulfate sulfatase, and characterized clinically by mainly musculoskeletal manifestations. The mechanisms underlying bone involvement in humans are typically explored using invasive techniques such as bone biopsy, which complicates analysis in humans. We compared bone proteomes using DDA and SWATH-MS in wild-type and MPS IVA knockout mice (UNT) to obtain mechanistic information about the disease. Our findings reveal over 1000 dysregulated proteins in knockout mice, including those implicated in oxidative phosphorylation, oxidative stress (reactive oxygen species), DNA damage, and iron transport, and suggest that lactate dehydrogenase may constitute a useful prognostic and follow-up biomarker. Identifying biomarkers that reflect MPS IVA clinical course, severity, and progression have important implications for disease management.
Topics: Humans; Animals; Mice; Mucopolysaccharidosis IV; Cartilage Diseases; Bone Diseases; Chondroitinsulfatases; Mice, Knockout
PubMed: 38542208
DOI: 10.3390/ijms25063232 -
Genes Mar 2024β-1,4-N-acetylgalactosamine transferase 2 () is a vital candidate gene that affects the growth traits in sheep. However, whether it has the same function in goats...
β-1,4-N-acetylgalactosamine transferase 2 () is a vital candidate gene that affects the growth traits in sheep. However, whether it has the same function in goats remains to be investigated further. This study selected 348 Nanjiang Yellow goats, screened all exons, and conserved non-coding regions of the gene for single-nucleotide polymorphisms (SNPs). Our results revealed the presence of a synonymous mutation, rs672215506, within the exon of the gene in the Nanjiang Yellow goat population. The mutation resulted in a decrease in the mRNA stability of the gene. The results of SNP detection of the conserved non-coding region of the gene showed five potential regulatory SNPs in the Nanjiang Yellow goat population. Except for rs66095343, the ~500 bp fragments of the other four SNPs (rs649127714, rs649573228, rs652899012, and rs639183528) significantly increased the luciferase activity both in goat skeletal muscle satellite cells (MuSCs) and 293T cells. The genetic diversity indexes indicated low or intermediate levels for all six SNPs analyzed, and the genotype frequencies were in Hardy-Weinberg equilibrium. Association analysis showed that rs660965343, rs649127714, and rs649573228 significantly correlate with growth traits in the later stage of growth and development of Nanjiang Yellow goats. The haplotype combinations of H2H3 and H2H2 had higher body weight and greater body size. Moreover, H2H2 haplotype combinations significantly correlated with the litter size of the Nanjiang Yellow goats. The results of our study demonstrate the potential role of the gene as a functional genetic marker in the breeding programs of Nanjiang Yellow goats.
Topics: Pregnancy; Female; Animals; Sheep; Goats; Polymorphism, Single Nucleotide; Genotype; Haplotypes; Litter Size
PubMed: 38540389
DOI: 10.3390/genes15030330