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Affiliation(s)
| | - Yang Ji
- University of California, San Diego
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Zaramela LS, Martino C, Alisson-Silva F, Rees SD, Diaz SL, Chuzel L, Ganatra MB, Taron CH, Secrest P, Zuñiga C, Huang J, Siegel D, Chang G, Varki A, Zengler K. Gut bacteria responding to dietary change encode sialidases that exhibit preference for red meat-associated carbohydrates. Nat Microbiol 2019; 4:2082-2089. [PMID: 31548686 PMCID: PMC6879853 DOI: 10.1038/s41564-019-0564-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 08/16/2019] [Indexed: 12/27/2022]
Abstract
Dietary habits have been associated with alterations of the human gut resident microorganisms contributing to obesity, diabetes and cancer1. In Western diets, red meat is a frequently eaten food2, but long-term consumption has been associated with increased risk of disease3,4. Red meat is enriched in N-glycolylneuraminic acid (Neu5Gc) that cannot be synthesized by humans5. However, consumption can cause Neu5Gc incorporation into cell surface glycans6, especially in carcinomas4,7. As a consequence, an inflammatory response is triggered when Neu5Gc-containing glycans encounter circulating anti-Neu5Gc antibodies8,9. Although bacteria can use free sialic acids as a nutrient source10-12, it is currently unknown if gut microorganisms contribute to releasing Neu5Gc from food. We found that a Neu5Gc-rich diet induces changes in the gut microbiota, with Bacteroidales and Clostridiales responding the most. Genome assembling of mouse and human shotgun metagenomic sequencing identified bacterial sialidases with previously unobserved substrate preference for Neu5Gc-containing glycans. X-ray crystallography revealed key amino acids potentially contributing to substrate preference. Additionally, we verified that mouse and human sialidases were able to release Neu5Gc from red meat. The release of Neu5Gc from red meat using bacterial sialidases could reduce the risk of inflammatory diseases associated with red meat consumption, including colorectal cancer4 and atherosclerosis13.
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Affiliation(s)
- Livia S Zaramela
- Department of Pediatrics, University of California, San Diego, CA, USA
| | - Cameron Martino
- Department of Pediatrics, University of California, San Diego, CA, USA.,Bioinformatics and Systems Biology Program, University of California, San Diego, CA, USA
| | - Frederico Alisson-Silva
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, CA, USA.,Glycobiology Research and Training Center, San Diego, CA, USA.,Paulo de Goes Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Steven D Rees
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
| | - Sandra L Diaz
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, CA, USA.,Glycobiology Research and Training Center, San Diego, CA, USA
| | | | | | | | - Patrick Secrest
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, CA, USA.,Glycobiology Research and Training Center, San Diego, CA, USA
| | - Cristal Zuñiga
- Department of Pediatrics, University of California, San Diego, CA, USA
| | - Jianbo Huang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
| | - Geoffrey Chang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, CA, USA
| | - Ajit Varki
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, CA, USA.,Glycobiology Research and Training Center, San Diego, CA, USA
| | - Karsten Zengler
- Department of Pediatrics, University of California, San Diego, CA, USA. .,Departmemt of Bioengineering, University of California, San Diego, CA, USA. .,Center for Microbiome Innovation, University of California, San Diego, CA, USA.
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Samraj AN, Bertrand KA, Luben R, Khedri Z, Yu H, Nguyen D, Gregg CJ, Diaz SL, Sawyer S, Chen X, Eliassen H, Padler-Karavani V, Wu K, Khaw KT, Willett W, Varki A. Polyclonal human antibodies against glycans bearing red meat-derived non-human sialic acid N-glycolylneuraminic acid are stable, reproducible, complex and vary between individuals: Total antibody levels are associated with colorectal cancer risk. PLoS One 2018; 13:e0197464. [PMID: 29912879 PMCID: PMC6005533 DOI: 10.1371/journal.pone.0197464] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/02/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND N-glycolylneuraminic acid (Neu5Gc) is a non-human red-meat-derived sialic acid immunogenic to humans. Neu5Gc can be metabolically incorporated into glycan chains on human endothelial and epithelial surfaces. This represents the first example of a "xeno-autoantigen", against which circulating human "xeno-autoantibodies" can react. The resulting inflammation ("xenosialitis") has been demonstrated in human-like Neu5Gc-deficient mice and contributed to carcinoma progression via antibody-mediated inflammation. Anti-Neu5Gc antibodies have potential as biomarkers for diseases associated with red meat consumption such as carcinomas, atherosclerosis, and type 2 diabetes. METHODS ELISA assays measured antibodies against Neu5Gc or Neu5Gc-glycans in plasma or serum samples from the Nurses' Health Studies, the Health Professionals Follow-up Study, and the European Prospective Investigation into Cancer and Nutrition, including inter-assay reproducibility, stability with delayed sample processing, and within-person reproducibility over 1-3 years in archived samples. We also assessed associations between antibody levels and coronary artery disease risk (CAD) or red meat intake. A glycan microarray was used to detected antibodies against multiple Neu5Gc-glycan epitopes. A nested case-control study design assessed the association between total anti-Neu5Gc antibodies detected in the glycan array assay and the risk of colorectal cancer (CRC). RESULTS ELISA assays showed a wide range of anti-Neu5Gc responses and good inter-assay reproducibility, stability with delayed sample processing, and within-person reproducibility over time, but these antibody levels did not correlate with CAD risk or red meat intake. Antibodies against Neu5Gc alone or against individual Neu5Gc-bearing epitopes were also not associated with colorectal cancer (CRC) risk. However, a sialoglycan microarray study demonstrated positive association with CRC risk when the total antibody responses against all Neu5Gc-glycans were combined. Individuals in the top quartile of total anti-Neu5Gc IgG antibody concentrations had nearly three times the risk compared to those in the bottom quartile (Multivariate Odds Ratio comparing top to bottom quartile: 2.98, 95% CI: 0.80, 11.1; P for trend = 0.02). CONCLUSIONS Further work harnessing the utility of these anti-Neu5Gc antibodies as biomarkers in red meat-associated diseases must consider diversity in individual antibody profiles against different Neu5Gc-bearing glycans. Traditional ELISA assays for antibodies directed against Neu5Gc alone, or against specific Neu5Gc-glycans may not be adequate to define risk associations. Our finding of a positive association of total anti-Neu5Gc antibodies with CRC risk also warrants confirmation in larger prospective studies.
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Affiliation(s)
- Annie N. Samraj
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Kimberly A. Bertrand
- Slone Epidemiology Center, Boston University, Boston, Massachusetts, United States of America
| | - Robert Luben
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Zahra Khedri
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Hai Yu
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Dzung Nguyen
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Christopher J. Gregg
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Sandra L. Diaz
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Sherilyn Sawyer
- Channing Division of Network Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Xi Chen
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Heather Eliassen
- Channing Division of Network Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Vered Padler-Karavani
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
| | - Kana Wu
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Kay-Tee Khaw
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Walter Willett
- Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Ajit Varki
- Department of Medicine, University of California, San Diego, California, United States of America
- Department of Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, California, United States of America
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Alisson-Silva F, Liu JZ, Diaz SL, Deng L, Gareau MG, Marchelletta R, Chen X, Nizet V, Varki N, Barrett KE, Varki A. Human evolutionary loss of epithelial Neu5Gc expression and species-specific susceptibility to cholera. PLoS Pathog 2018; 14:e1007133. [PMID: 29912959 PMCID: PMC6023241 DOI: 10.1371/journal.ppat.1007133] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 06/28/2018] [Accepted: 06/01/2018] [Indexed: 01/31/2023] Open
Abstract
While infectious agents have typical host preferences, the noninvasive enteric bacterium Vibrio cholerae is remarkable for its ability to survive in many environments, yet cause diarrheal disease (cholera) only in humans. One key V. cholerae virulence factor is its neuraminidase (VcN), which releases host intestinal epithelial sialic acids as a nutrition source and simultaneously remodels intestinal polysialylated gangliosides into monosialoganglioside GM1. GM1 is the optimal binding target for the B subunit of a second virulence factor, the AB5 cholera toxin (Ctx). This coordinated process delivers the CtxA subunit into host epithelia, triggering fluid loss via cAMP-mediated activation of anion secretion and inhibition of electroneutral NaCl absorption. We hypothesized that human-specific and human-universal evolutionary loss of the sialic acid N-glycolylneuraminic acid (Neu5Gc) and the consequent excess of N-acetylneuraminic acid (Neu5Ac) contributes to specificity at one or more steps in pathogenesis. Indeed, VcN was less efficient in releasing Neu5Gc than Neu5Ac. We show enhanced binding of Ctx to sections of small intestine and isolated polysialogangliosides from human-like Neu5Gc-deficient Cmah-/- mice compared to wild-type, suggesting that Neu5Gc impeded generation of the GM1 target. Human epithelial cells artificially expressing Neu5Gc were also less susceptible to Ctx binding and CtxA intoxication following VcN treatment. Finally, we found increased fluid secretion into loops of Cmah-/- mouse small intestine injected with Ctx, indicating an additional direct effect on ion transport. Thus, V. cholerae evolved into a human-specific pathogen partly by adapting to the human evolutionary loss of Neu5Gc, optimizing multiple steps in cholera pathogenesis.
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Affiliation(s)
- Frederico Alisson-Silva
- Glycobiology Research and Training Center (GRTC), Center for Academic Research and Training in Anthropogeny (CARTA), Departments of Medicine and Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Janet Z. Liu
- Department of Pediatrics, University of California San Diego, La Jolla, CA, United States of America
| | - Sandra L. Diaz
- Glycobiology Research and Training Center (GRTC), Center for Academic Research and Training in Anthropogeny (CARTA), Departments of Medicine and Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Lingquan Deng
- Glycobiology Research and Training Center (GRTC), Center for Academic Research and Training in Anthropogeny (CARTA), Departments of Medicine and Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Mélanie G. Gareau
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Ronald Marchelletta
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Xi Chen
- Department of Chemistry, University of California Davis, Davis CA, United States of America
| | - Victor Nizet
- Department of Pediatrics, University of California San Diego, La Jolla, CA, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Nissi Varki
- Glycobiology Research and Training Center (GRTC), Center for Academic Research and Training in Anthropogeny (CARTA), Departments of Medicine and Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Kim E. Barrett
- Division of Gastroenterology, Department of Medicine, University of California San Diego, La Jolla, CA, United States of America
- * E-mail: (AV); (KEB)
| | - Ajit Varki
- Glycobiology Research and Training Center (GRTC), Center for Academic Research and Training in Anthropogeny (CARTA), Departments of Medicine and Cellular & Molecular Medicine, University of California San Diego, La Jolla, CA, United States of America
- * E-mail: (AV); (KEB)
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Springer SA, Diaz SL, Gagneux P. Parallel evolution of a self-signal: humans and new world monkeys independently lost the cell surface sugar Neu5Gc. Immunogenetics 2014; 66:671-4. [PMID: 25124893 DOI: 10.1007/s00251-014-0795-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 08/05/2014] [Indexed: 12/20/2022]
Abstract
Human sialic acid biology is unusual and thought to be unique among mammals. Humans lack a functional cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) protein and cannot synthesize the sugar Neu5Gc, an innate mammalian signal of self. Losing this sugar changed how humans interact with some of our deadliest pathogens: malaria, influenza, and streptococcus among others. We show that the New World monkeys, comprising the third of all primate species, have human-like sialic acid biology. They have lost Neu5Gc because of an independent CMAH inactivation ~30 million years ago (mya) (compared to ~3 mya in hominids). This parallel loss of Neu5Gc opens sialic acid biology to comparative phylogenetic analysis and reveals an unexpected conservation priority. New World monkeys risk infection by human pathogens that can recognize cells in the absence of Neu5Gc. This striking molecular convergence provides a mechanism that could explain the long-standing observation that New World monkeys are susceptible to some human diseases that cannot be transmitted to other primates.
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Affiliation(s)
- Stevan A Springer
- Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
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Samraj A, Crittenden A, Banda K, Gregg CJ, Assar S, Diaz SL, Varki N, Varki A. Diet‐derived Xeno‐autoantigen Sialic acid Promotes Inflammation ‐ Evidence for “Xenosialitis”. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.lb488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Nissi Varki
- Cellular and Molecular MedicineUCSDLa JollaCA
| | - Ajit Varki
- Cellular and Molecular MedicineUCSDLa JollaCA
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Bergfeld AK, Pearce OMT, Diaz SL, Lawrence R, Vocadlo DJ, Choudhury B, Esko JD, Varki A. Metabolism of vertebrate amino sugars with N-glycolyl groups: incorporation of N-glycolylhexosamines into mammalian glycans by feeding N-glycolylgalactosamine. J Biol Chem 2012; 287:28898-916. [PMID: 22692203 DOI: 10.1074/jbc.m112.363499] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The outermost positions of mammalian cell-surface glycans are predominantly occupied by the sialic acids N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc). To date, hydroxylation of CMP-Neu5Ac resulting in the conversion into CMP-Neu5Gc is the only known enzymatic reaction in mammals to synthesize a monosaccharide carrying an N-glycolyl group. In our accompanying paper (Bergfeld, A. K., Pearce, O. M., Diaz, S. L., Pham, T., and Varki, A. (2012) J. Biol. Chem. 287, jbc.M112.363549), we report a metabolic pathway for degradation of Neu5Gc, demonstrating that N-acetylhexosamine pathways are tolerant toward the N-glycolyl substituent of Neu5Gc breakdown products. In this study, we show that exogenously added N-glycolylgalactosamine (GalNGc) serves as a precursor for Neu5Gc de novo biosynthesis, potentially involving seven distinct mammalian enzymes. Following the GalNAc salvage pathway, UDP-GalNGc is epimerized to UDP-GlcNGc, which might compete with the endogenous UDP-GlcNAc for the sialic acid biosynthetic pathway. Using UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase-deficient cells, we confirm that conversion of GalNGc into Neu5Gc depends on this key enzyme of sialic acid biosynthesis. Furthermore, we demonstrate by mass spectrometry that the metabolic intermediates UDP-GalNGc and UDP-GlcNGc serve as substrates for assembly of most major classes of cellular glycans. We show for the first time incorporation of GalNGc and GlcNGc into chondroitin/dermatan sulfates and heparan sulfates, respectively. As demonstrated by structural analysis, N-glycolylated hexosamines were found in cellular gangliosides and incorporated into Chinese hamster ovary cell O-glycans. Remarkably, GalNAc derivatives altered the overall O-glycosylation pattern as indicated by the occurrence of novel O-glycan structures. This study demonstrates that mammalian N-acetylhexosamine pathways and glycan assembly are surprisingly tolerant toward the N-glycolyl substituent.
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Affiliation(s)
- Anne K Bergfeld
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California 92093-0687, USA
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Bergfeld AK, Pearce OMT, Diaz SL, Pham T, Varki A. Metabolism of vertebrate amino sugars with N-glycolyl groups: elucidating the intracellular fate of the non-human sialic acid N-glycolylneuraminic acid. J Biol Chem 2012; 287:28865-81. [PMID: 22692205 DOI: 10.1074/jbc.m112.363549] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two major mammalian sialic acids are N-acetylneuraminic acid and N-glycolylneuraminic acid (Neu5Gc). The only known biosynthetic pathway generating Neu5Gc is the conversion of CMP-N-acetylneuraminic acid into CMP-Neu5Gc, which is catalyzed by the CMP-Neu5Ac hydroxylase enzyme. Given the irreversible nature of this reaction, there must be pathways for elimination or degradation of Neu5Gc, which would allow animal cells to adjust Neu5Gc levels to their needs. Although humans are incapable of synthesizing Neu5Gc due to an inactivated CMAH gene, exogenous Neu5Gc from dietary sources can be metabolically incorporated into tissues in the face of an anti-Neu5Gc antibody response. However, the metabolic turnover of Neu5Gc, which apparently prevents human cells from continued accumulation of this immunoreactive sialic acid, has not yet been elucidated. In this study, we show that pre-loaded Neu5Gc is eliminated from human cells over time, and we propose a conceivable Neu5Gc-degrading pathway based on the well studied metabolism of N-acetylhexosamines. We demonstrate that murine tissue cytosolic extracts harbor the enzymatic machinery to sequentially convert Neu5Gc into N-glycolylmannosamine, N-glycolylglucosamine, and N-glycolylglucosamine 6-phosphate, whereupon irreversible de-N-glycolylation of the latter results in the ubiquitous metabolites glycolate and glucosamine 6-phosphate. We substantiate this finding by demonstrating activity of recombinant human enzymes in vitro and by studying the fate of radiolabeled pathway intermediates in cultured human cells, suggesting that this pathway likely occurs in vivo. Finally, we demonstrate that the proposed degradative pathway is partially reversible, showing that N-glycolylmannosamine and N-glycolylglucosamine (but not glycolate) can serve as precursors for biosynthesis of endogenous Neu5Gc.
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Affiliation(s)
- Anne K Bergfeld
- Department of Medicine, Glycobiology Research and Training Center, University of California San Diego, La Jolla, California 92093-0687, USA
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Jessani N, Young JA, Diaz SL, Patricelli MP, Varki A, Cravatt BF. Class assignment of sequence-unrelated members of enzyme superfamilies by activity-based protein profiling. Angew Chem Int Ed Engl 2006; 44:2400-3. [PMID: 15765498 DOI: 10.1002/anie.200463098] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nadim Jessani
- Skaggs Institute for Chemical Biology and Department of Cell Biology, Scripps Research Institute, La Jolla, CA 92037, USA
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Abstract
As parasitized rodents are not desirable experimental objects, it is important to maintain parasite-free laboratory rodent colonies. Faced with the task of eliminating pediculosis from a conventional laboratory rat colony whose individuals were intended to be used in scientific research, a drug treatment was needed which did not, or minimally, interfere with experimental results. Fipronil, a GABA(A) antagonist, is an effective drug against lice, fleas and mites currently used in domestic species. Fipronil is not absorbed, has a wide safety margin and is topically applied. The aim of this study was to treat an infected colony with Frontline Spray (0.25%-w/v-fipronil) in order to evaluate its efficacy against lice. Rats were sprayed with Frontline only once. Special procedures to prevent cross-contamination between cages were not used. Neither lice nor nits were found during any post-treatment examination. In addition, no complications were reported by any researcher after using the treated rats in their experiments. The results of this study demonstrate that fipronil in topical formulations is effective for treatment and control of sucking and biting lice infestations on laboratory rats.
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Affiliation(s)
- S L Diaz
- Instituto de Investigaciones Farmacológicas, CONICET, Buenos Aires, Argentina.
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Jessani N, Young JA, Diaz SL, Patricelli MP, Varki A, Cravatt BF. Class Assignment of Sequence-Unrelated Members of Enzyme Superfamilies by Activity-Based Protein Profiling. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200463098] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Abstract
In previous studies we have demonstrated a possible interaction between the GABAergic and opioid systems involved in the antinociceptive effect of the GABA(B) agonist, baclofen (BAC). On the other hand, sex differences have been observed for the antinociceptive effect of morphine (MOR). In the present study, we analyzed sex-related differences in the MOR abstinence syndrome and its prevention with BAC. Prepubertal male and female Swiss-Webster albino mice (27-33 g) were rendered dependent by intraperitoneal (i.p.) injection of MOR (2, 4 and 8 mg/kg), twice daily for 9 days. On the tenth day the dependent animals were divided into two groups: one received naloxone (NAL) (6 mg/kg, i.p.) 60 min after the last dose of MOR, to precipitate the abstinence syndrome; the other group received BAC (2 mg/kg, i.p.) followed by NAL (6 mg/kg, i.p.), injected 30 and 60 min after the last dose of MOR, respectively. Behavioral signs were recorded in the open field for 30 min. Although there were sex differences in the MOR withdrawal syndrome, we found a lack of sex differences in the prevention of the MOR abstinence syndrome by BAC.
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Affiliation(s)
- S L Diaz
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica (Universidad de Buenos Aires), Argentina
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Diaz SL. Assessing single-purpose institutions through the accreditation process. NLN Publ 1985:65-8. [PMID: 3846899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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