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Journal of Lipid and Atherosclerosis Jan 2024Apolipoprotein C3 (apoC3) and angiopoietin-like protein 3 (ANGPTL3) inhibit lipolysis by lipoprotein lipase and may influence the secretion and uptake of various... (Review)
Review
Apolipoprotein C3 (apoC3) and angiopoietin-like protein 3 (ANGPTL3) inhibit lipolysis by lipoprotein lipase and may influence the secretion and uptake of various lipoproteins. Genetic studies show that depletion of these proteins is associated with improved lipid profiles and reduced cardiovascular events so it was anticipated that drugs which mimic the effects of loss-of-function mutations would be useful lipid treatments. ANGPTL3 inhibitors were initially developed as a treatment for severe hypertriglyceridaemia including familial chylomicronaemia syndrome (FCS), which is usually not adequately controlled with currently available drugs. However, it was found ANGPTL3 inhibitors were also effective in reducing low-density lipoprotein cholesterol (LDL-C) and they were studied in patients with homozygous familial hypercholesterolaemia (FH). Evinacumab targets ANGPTL3 and reduced LDL-C by about 50% in patients with homozygous FH and it has been approved for that indication. The antisense oligonucleotide (ASO) vupanorsen targeting ANGPTL3 was less effective in reducing LDL-C in patients with moderate hypertriglyceridaemia and its development has been discontinued but the small interfering RNA (siRNA) ARO-ANG3 is being investigated in Phase 2 studies. ApoC3 can be inhibited by the ASO volanesorsen, which reduced triglycerides by >70% in patients with FCS and it was approved for FCS in Europe but not in the United States because of concerns about thrombocytopaenia. Olezarsen is an N-acetylgalactosamine-conjugated ASO targeting apoC3 which appears as effective as volanesorsen without the risk of thrombocytopaenia and is undergoing Phase 3 trials. ARO-APOC3 is an siRNA targeting apoC3 that is currently being investigated in Phase 3 studies.
PubMed: 38299167
DOI: 10.12997/jla.2024.13.1.2 -
Nature Jan 2024Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established, little is known about how host genetics regulates... (Meta-Analysis)
Meta-Analysis
Although the impact of host genetics on gut microbial diversity and the abundance of specific taxa is well established, little is known about how host genetics regulates the genetic diversity of gut microorganisms. Here we conducted a meta-analysis of associations between human genetic variation and gut microbial structural variation in 9,015 individuals from four Dutch cohorts. Strikingly, the presence rate of a structural variation segment in Faecalibacterium prausnitzii that harbours an N-acetylgalactosamine (GalNAc) utilization gene cluster is higher in individuals who secrete the type A oligosaccharide antigen terminating in GalNAc, a feature that is jointly determined by human ABO and FUT2 genotypes, and we could replicate this association in a Tanzanian cohort. In vitro experiments demonstrated that GalNAc can be used as the sole carbohydrate source for F. prausnitzii strains that carry the GalNAc-metabolizing pathway. Further in silico and in vitro studies demonstrated that other ABO-associated species can also utilize GalNAc, particularly Collinsella aerofaciens. The GalNAc utilization genes are also associated with the host's cardiometabolic health, particularly in individuals with mucosal A-antigen. Together, the findings of our study demonstrate that genetic associations across the human genome and bacterial metagenome can provide functional insights into the reciprocal host-microbiome relationship.
Topics: Humans; Acetylgalactosamine; Bacteria; Cohort Studies; Computer Simulation; Faecalibacterium prausnitzii; Gastrointestinal Microbiome; Genome, Human; Genotype; Host Microbial Interactions; In Vitro Techniques; Metagenome; Multigene Family; Netherlands; Tanzania
PubMed: 38172637
DOI: 10.1038/s41586-023-06893-w -
Biochemistry Jan 2024The genus of Gram-negative bacteria is characterized by the expression of N-linked protein glycosylation (pgl) pathways. As is an emerging human pathogen, a better...
The genus of Gram-negative bacteria is characterized by the expression of N-linked protein glycosylation (pgl) pathways. As is an emerging human pathogen, a better understanding of the variation of the biosynthetic pathways across the genus is necessary to identify the relationships between protein glycosylation and disease. The pgl pathways of strains have been reported to diverge from other in steps after the biosynthesis of acetylgalactosamine-α1,3-diacetylbacillosamine-α-1-diphosphate undecaprenyl (GalNAc-diNAcBac-PP-Und), which is catalyzed by PglC and PglA, a phosphoglycosyltransferase (PGT) and a glycosyltransferase (GT), respectively. Here we characterize the PglJ GTs from two strains of . Chemical synthesis was employed to access the stereochemically defined glycan donor substrates, uridine diphosphate -acetyl-d-galactosaminuronic acid (UDP-GalNAcA) and uridine diphosphate -acetyl-d-glucosaminuronic acid (UDP-GlcNAcA), to allow biochemical investigation of PglJ. Evidence for the PglJ substrate specificity structural determinants for the C6″ carboxylate-containing sugar was obtained through variant-based biochemical assays. Additionally, characterization of a UDP-sugar dehydrogenase encoded in the pgl operon, which is similar to the WbpO responsible for the oxidization of a UDP-HexNAc to UDP-HexNAcA, supports the availability of a UDP-HexNAcA substrate for a GT that incorporates the modified sugar and provides evidence for the presence of a HexNAcA in the N-linked glycan. Utilizing sequence similarity network (SSN) analysis, we identified conserved sequence motifs among PglJ glycosyltransferases, shedding light on substrate preferences and offering predictive insights into enzyme functions across the genus. These studies now allow detailed characterization of the later steps in the pgl pathway in strains and provide insights into enzyme substrate specificity determinants for glycan assembly enzymes.
Topics: Humans; Glycosyltransferases; Glycosylation; Polysaccharides; Campylobacter; Uridine Diphosphate; Sugars
PubMed: 38110367
DOI: 10.1021/acs.biochem.3c00564 -
Glycosyltransferase 8 domain-containing protein 1 (GLT8D1) is a UDP-dependent galactosyltransferase.Scientific Reports Dec 2023Glycosyltransferases (GTs) are enzymes that catalyze the formation of glycosidic bonds and hundreds of GTs have been identified so far in humans. Glycosyltransferase 8...
Glycosyltransferases (GTs) are enzymes that catalyze the formation of glycosidic bonds and hundreds of GTs have been identified so far in humans. Glycosyltransferase 8 domain-containing protein 1 (GLT8D1) has been associated with central nervous system diseases and cancer. However, evidence on its enzymatic properties, including its substrates, has been scarcely described. In this paper, we have produced and purified recombinant secretory GLT8D1. The enzyme was found to be N-glycosylated. Differential scanning fluorimetry was employed to analyze the stabilization of GLT8D1 by Mn and nucleotides, revealing UDP as the most stabilizing nucleotide scaffold. GLT8D1 displayed glycosyltransferase activity from UDP-galactose onto N-acetylgalactosamine but with a low efficiency. Modeling of the structure revealed similarities with other GT-A fold enzymes in CAZy family GT8 and glycosyltransferases in other families with galactosyl-, glucosyl-, and xylosyltransferase activities, each with retaining catalytic mechanisms. Our study provides novel structural and functional insights into the properties of GLT8D1 with implications in pathological processes.
Topics: Humans; Galactosyltransferases; Glycosyltransferases; Catalysis; Uridine Diphosphate
PubMed: 38066107
DOI: 10.1038/s41598-023-48605-4 -
Journal of the Formosan Medical... Jun 2024Acute hepatic porphyrias (AHP) are rare genetic disorders associated with acute neurovisceral attacks and chronic symptoms. This analysis was conducted to examine the... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND/PURPOSE
Acute hepatic porphyrias (AHP) are rare genetic disorders associated with acute neurovisceral attacks and chronic symptoms. This analysis was conducted to examine the long-term efficacy and safety of givosiran in Taiwanese participants in the ENVISION study (NCT03338816).
METHODS
Patients (age ≥12 years) with AHP and recurrent attacks were randomized to receive givosiran 2.5 mg/kg or placebo for 6 months during the double-blind period. Patients then switched from placebo to givosiran (placebo crossover group) or continued taking givosiran (continuous givosiran group) during a 30-month open-label extension period. The total study duration was 36 months. An analysis was conducted that included patients enrolled in Taiwan (N = 7).
RESULTS
During the double-blind period and open-label extension period, the median annualized attack rates were 0.0 and 0.0, respectively, in the continuous givosiran group (n = 5) and 15.1 and 4.6, respectively, in the placebo crossover group (n = 2; 70 % decrease). Median annualized days of hemin use in the double-blind period and open-label extension period were 0.0 and 0.0, respectively, in the continuous givosiran group, and 23.8 and 5.0, respectively, in the placebo crossover group (79 % decrease). EQ-5D VAS scores remained relatively stable in both groups, and PPEQ responses indicated improved functioning and satisfaction in both groups. Delta-aminolevulinic acid and porphobilinogen levels remained low with long-term givosiran treatment. Serious adverse events were reported by 3 patients (43 %).
CONCLUSION
Long-term efficacy and safety results in the Taiwan cohort are consistent with those in the global cohort.
Topics: Humans; Male; Female; Double-Blind Method; Taiwan; Adult; Middle Aged; Porphyrias, Hepatic; Young Adult; Treatment Outcome; Acetylgalactosamine; Cross-Over Studies; Aged; Adolescent; Carbamates; Quality of Life; Pyrrolidines
PubMed: 38044204
DOI: 10.1016/j.jfma.2023.10.016 -
Oncology Letters Dec 2023Fibrosarcoma is a highly malignant type of soft tissue sarcoma that currently lacks effective treatment options. Polypeptide N-acetylgalactosaminyltransferase 12...
Fibrosarcoma is a highly malignant type of soft tissue sarcoma that currently lacks effective treatment options. Polypeptide N-acetylgalactosaminyltransferase 12 (GALNT12) belongs to the uridine diphosphate N-acetylgalactosamine gene family, which is involved in numerous biological processes of diseases, such as tumor progression. Its upregulated expression is closely associated with the development of colorectal cancer. However, research on the role of GALNT12 in fibrosarcoma is currently limited. The present study aimed to assess the expression and biological function of GALNT12 in fibrosarcoma. Patient data and tissue samples were collected and public datasets were obtained from the Gene Expression Omnibus (GSE24369 and GSE21124). Immunofluorescence assays were performed to observe the cellular localization of GALNT12. GALNT12 expression was measured using reverse transcription-quantitative PCR, western blotting and immunohistochemistry. Small interfering RNAs were constructed to knock down GALNT12 expression in HT-1080 cells. Cell Counting Kit-8 and EdU assays were used to assess fibrosarcoma cell proliferation. Wound healing and Transwell assays were used to detect migration. Gene set enrichment analysis was performed to identify key pathways. Paired and unpaired Student's t-test, Fisher's exact test and one-way ANOVA (followed by Tukey's Honest Significant Difference test) were used to analyze the data. It was demonstrated that GALNT12 expression was upregulated in both fibrosarcoma cell lines and tissue samples and predicted poor patient prognosis. experiments demonstrated that high GALNT12 expression levels significantly increased HT-1080 cell proliferation and migration. Furthermore, it was demonstrated that high GALNT12 expression levels were closely associated with the yes1 associated transcriptional regulator (YAP1) signaling pathway. Knockdown of GALNT12 inhibited YAP1 nuclear translocation, which affected activation of key downstream genes including AMOTL2, BIRC5 and CYR61. Therefore, the present study demonstrated that GALNT12 promoted fibrosarcoma progression. GALNT12 could be a potential biomarker for this disease and may potentially provide new ideas for targeted therapy of fibrosarcoma in the future.
PubMed: 38020290
DOI: 10.3892/ol.2023.14131 -
International Journal of Molecular... Nov 2023Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase () encoding gene. GALNS leads to the... (Review)
Review
Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase () encoding gene. GALNS leads to the lysosomal degradation of the glycosaminoglyccreasans keratan sulfate and chondroitin 6-sulfate. Impaired GALNS enzymes result in skeletal and non-skeletal complications in patients. For years, the MPS IVA pathogenesis and the assessment of promising drugs have been evaluated using in vitro (primarily fibroblasts) and in vivo (mainly mouse) models. Even though value information has been raised from those studies, these models have several limitations. For instance, chondrocytes have been well recognized as primary cells affected in MPS IVA and responsible for displaying bone development impairment in MPS IVA patients; nonetheless, only a few investigations have used those cells to evaluate basic and applied concepts. Likewise, current animal models are extensively represented by mice lacking GALNS expression; however, it is well known that MPS IVA mice do not recapitulate the skeletal dysplasia observed in humans, making some comparisons difficult. This manuscript reviews the current in vitro and in vivo MPS IVA models and their drawbacks.
Topics: Humans; Mice; Animals; Mucopolysaccharidosis IV; Keratan Sulfate; Chondroitin Sulfates; Chondrocytes; Disease Models, Animal; Chondroitinsulfatases
PubMed: 38003337
DOI: 10.3390/ijms242216148 -
Arteriosclerosis, Thrombosis, and... Dec 2023Blood pressure management involves antihypertensive therapies blocking the renin-angiotensin system (RAS). Yet, it might be inadequate due to poor patient adherence or... (Review)
Review
Blood pressure management involves antihypertensive therapies blocking the renin-angiotensin system (RAS). Yet, it might be inadequate due to poor patient adherence or the so-called RAS escape phenomenon, elicited by the compensatory renin elevation upon RAS blockade. Recently, evidence points toward targeting hepatic AGT (angiotensinogen) as a novel approach to block the RAS pathway that could circumvent the RAS escape phenomenon. Removing AGT, from which all angiotensins originate, should prevent further angiotensin generation, even when renin rises. Furthermore, by making use of a trivalent -acetylgalactosamine ligand-conjugated small interfering RNA that specifically targets the degradation of hepatocyte-produced mRNAs in a highly potent and specific manner, it may be possible in the future to manage hypertension with therapy that is administered 1 to 2× per year, thereby supporting medication adherence. This review summarizes all current findings on AGT small interfering RNA in preclinical models, making a comparison versus classical RAS blockade with either ACE (angiotensin-converting enzyme) inhibitors or AT1 (angiotensin II type 1) receptor antagonists and AGT suppression with antisense oligonucleotides. It ends with discussing the first-in-human study with AGT small interfering RNA.
Topics: Humans; Acetylgalactosamine; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Blood Pressure; Hypertension; Renin; Renin-Angiotensin System; RNA, Small Interfering
PubMed: 37855126
DOI: 10.1161/ATVBAHA.123.319897 -
Clinical Pharmacokinetics Dec 2023Small-interfering ribonucleic acids (siRNAs) with N-acetylgalactosamine (GalNAc) conjugation for improved liver uptake represent an emerging class of drugs that modulate...
Small-interfering ribonucleic acids (siRNAs) with N-acetylgalactosamine (GalNAc) conjugation for improved liver uptake represent an emerging class of drugs that modulate liver-expressed therapeutic targets. The pharmacokinetics of GalNAc-siRNAs are characterized by a rapid distribution from plasma to tissue (hours) and a long terminal plasma half-life, analyzed in the form of the antisense strand, driven by redistribution from tissue (weeks). Understanding how clinical pharmacokinetics relate to the dose and type of siRNA chemical stabilizing method used is critical, e.g., to design studies, to investigate safety windows, and to predict the pharmacokinetics of new preclinical assets. To this end, we collected and analyzed pharmacokinetic data from the literature regarding nine GalNAc-siRNAs. Based on this analysis, we showed that the clinical plasma pharmacokinetics of GalNAc-siRNAs are approximately dose proportional and similar between chemical stabilizing methods. This holds for both the area under the concentration-time curve (AUC) and the maximum plasma concentration (C). Corresponding rat and monkey pharmacokinetic data for a subset of the nine GalNAc-siRNAs show dose-proportional C, supra-dose-proportional AUC, and similar pharmacokinetics between chemical stabilizing methods. Together, the animal and human pharmacokinetic data indicate that plasma clearance divided by bioavailability follows allometric principles and scales between species with an exponent of 0.75. Finally, the clinical plasma concentration-time profiles can be empirically described by standard one-compartment kinetics with first-order absorption up to 24 h after subcutaneous dosing, and by three-compartment kinetics with first-order absorption in general. To describe the system more mechanistically, we report a corrected and unambiguously defined version of a previously published physiologically based pharmacokinetic model.
Topics: Humans; Rats; Animals; Acetylgalactosamine; Liver; RNA, Small Interfering; Biological Availability
PubMed: 37824025
DOI: 10.1007/s40262-023-01314-7 -
Current Opinion in Lipidology Dec 2023The aim of this study was to discuss the potential mechanisms and implications of the opposing liver safety results from recent angiopoietin-like 3 (ANGPTL3) inhibition... (Review)
Review
PURPOSE OF REVIEW
The aim of this study was to discuss the potential mechanisms and implications of the opposing liver safety results from recent angiopoietin-like 3 (ANGPTL3) inhibition studies.
RECENT FINDINGS
The clinical development of vupanorsen, a N-acetylgalactosamine (GalNAc) antisense targeting hepatic ANGPTL3, was recently discontinued due to a significant signal of liver transaminase increase. Vupanorsen elicited a dose-dependent increase in hepatic fat fraction up to 75%, whereas the small interfering RNA (siRNA) ARO-ANG3, has reported preliminary evidence of a dose-dependent decrease in hepatic fat fraction up to 30%.
SUMMARY
ANGPTL3 inhibition is an attractive therapeutic target to reduce all apoB-containing lipoproteins. The discrepancy in liver signal results between the antisense and siRNA approach may be explained by the level of target inhibition. An alternative explanation may relate to off-target effects of vupanorsen, which have a molecule- and/or platform-specific origin. For intrahepatic strategies, highly potent ANGPTL3 inhibition will for now require special attention for liver safety.
Topics: Humans; Angiopoietin-like Proteins; Angiopoietin-Like Protein 3; Liver; RNA, Small Interfering; Angiopoietins
PubMed: 37820081
DOI: 10.1097/MOL.0000000000000898