1. |
- Bi, Huijuan, et al.
(author)
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A frame-shift mutation in COMTD1 is associated with impaired pheomelanin pigmentation in chicken
- 2023
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In: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 19:4
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Journal article (peer-reviewed)abstract
- The biochemical pathway regulating the synthesis of yellow/red pheomelanin is less well characterized than the synthesis of black/brown eumelanin. Inhibitor of gold (IG phenotype) is a plumage colour variant in chicken that provides an opportunity to further explore this pathway since the recessive allele (IG) at this locus is associated with a defect in the production of pheomelanin. IG/IG homozygotes display a marked dilution of red pheomelanin pigmentation, whilst black pigmentation (eumelanin) is only slightly affected. Here we show that a 2-base pair insertion (frame-shift mutation) in the 5th exon of the Catechol-O-methyltransferase containing domain 1 gene (COMTD1), expected to cause a complete or partial loss-of-function of the COMTD1 enzyme, shows complete concordance with the IG phenotype within and across breeds. We show that the COMTD1 protein is localized to mitochondria in pigment cells. Knockout of Comtd1 in a mouse melanocytic cell line results in a reduction in pheomelanin metabolites and significant alterations in metabolites of glutamate/glutathione, riboflavin, and the tricarboxylic acid cycle. Furthermore, COMTD1 overexpression enhanced cellular proliferation following chemical-induced transfection, a potential inducer of oxidative stress. These observations suggest that COMTD1 plays a protective role for melanocytes against oxidative stress and that this supports their ability to produce pheomelanin.
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2. |
- Kaur, Amanpreet, et al.
(author)
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Chemoselective bicyclobutane-based mass spectrometric detection of biological thiols uncovers human and bacterial metabolites
- 2023
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In: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 14:20, s. 5291-5301
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Journal article (peer-reviewed)abstract
- Sulfur is an essential element of life. Thiol-containing metabolites in all organisms are involved in the regulation of diverse biological processes. Especially, the microbiome produces bioactive metabolites or biological intermediates of this compound class. The analysis of thiol-containing metabolites is challenging due to the lack of specific tools, making these compounds difficult to investigate selectively. We have now developed a new methodology comprising bicyclobutane for chemoselective and irreversible capturing of this metabolite class. We utilized this new chemical biology tool immobilized onto magnetic beads for the investigation of human plasma, fecal samples, and bacterial cultures. Our mass spectrometric investigation detected a broad range of human, dietary and bacterial thiol-containing metabolites and we even captured the reactive sulfur species cysteine persulfide in both fecal and bacterial samples. The described comprehensive methodology represents a new mass spectrometric strategy for the discovery of bioactive thiol-containing metabolites in humans and the microbiome.
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3. |
- Lin, Weifeng
(author)
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Development of advanced chemical biology tools for microbiome metabolism : Chemoselective probes for enhanced metabolomics analysis
- 2023
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Doctoral thesis (other academic/artistic)abstract
- The human microbiome has a profound impact on host physiology by generating highly reactive compounds that can contribute to the development of diseases. These microbial metabolites have a substantial potential that can serve as valuable indicators or biomarkers for different health conditions. Nevertheless, elucidating the microbiota composition and function remains challenging due to its remarkable diversity and complex. Furthermore, conducting a comprehensive analysis of the entire metabolome in a single analytical measurement is difficult. Researchers often employ derivatization techniques in analytical chemistry, which involve modifying the chemical structure of molecules to enhance their detectability, ionization properties and stability during analysis. However, derivatization carries the risk of introducing artifacts or chemical alterations that may compromise the accuracy of analytical results. Consequently, more advanced techniques are urgently required to improve the precision of derivatization-based metabolomics.In response to this challenge, we have developed chemoselective probes immobilized onto magnetic beads to capture metabolites within biological samples. This innovative method improves the mass spectrometric sensitivity by up to a factor of one million, due to the efficient removal of sample matrix background through magnetic separation and improved ionization properties of the metabolites via derivatization. Our approach, termed quant-SCHEMA, has demonstrated the qualitative detection of metabolites containing carbonyl and amine groups with exceptional sensitivity and reproducibility. Additionally, we have successfully applied this method with improved probe design to quantitatively analyse carbonyl-containing metabolites, leading to the discovery of four valuable nutritional biomarkers. Furthermore, we have developed a precise quantification method for short-chain fatty acids (SCFAs) based on this chemoselective probe. The successful implementation of our chemoselective probes highlights the importance of chemical biology tools in advancing metabolomics, which we have termed chemical metabolomics,This comprehensive mass spectrometric analysis expands the horizons of metabolomics-driven biomarker discovery. We envision that our innovative chemical biology tool will find widespread utility in metabolomics analysis, providing valuable insights into microbial interactions with the human host and the development of diseases.
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4. |
- Lin, Weifeng, et al.
(author)
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Identification of nutritional biomarkers through highly sensitive and chemoselective metabolomics
- 2023
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In: Food Chemistry. - : Elsevier. - 0308-8146 .- 1873-7072. ; 425
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Journal article (peer-reviewed)abstract
- The importance of a healthy diet for humans is known for decades. The elucidation of key molecules responsible for the beneficial and adverse dietary effects is slowly developing as the tools are missing. Carbonyl-containing metabolites are a common bioproducts through conversion of diet by the microbiome. In here, we have utilized our recently developed mass spectrometric methodology based on chemoselective conjugation of carbonyl-metabolites. The method has been applied for urine sample analysis from a dietary (poly)phenol intervention study (N = 78 individuals) for the first time. We have identified a series of carbonyl-metabolites of dietary origin and the chemical structure was validated for 30 metabolites. Our sensitive analysis led to the discovery of four unknown dietary markers with high sensitivity and selectivity (AUC > 0.91). Our chemical metabolomics method has been successfully applied for large-scale analysis and provides the basis for targeted metabolomics to identify unknown nutritional and disease-related biomarkers.
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5. |
- Lin, Weifeng, et al.
(author)
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Sensitive quantification of short-chain fatty acids combined with global metabolomics in microbiome cultures
- 2023
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In: Chemical Communications. - : Royal Society of Chemistry. - 1359-7345 .- 1364-548X. ; 59:39, s. 5843-5846
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Journal article (peer-reviewed)abstract
- The microbiome has been identified to have a key role for the physiology of their human host. One of the major impacts is the clearance of bacterial pathogens. We have now developed a chemoselective probe methodology for the absolute quantification of short-chain fatty acids at low nM concentrations, with high reproducibility and spiked isotope labelled internal standards. Immobilization to magnetic beads allows for separation from the matrix and the tagged metabolites upon bioorthogonal cleavage can be analyzed via UHPLC-MS. The major advantage of our sensitive method is the simple combination with global metabolomics analysis as only a small sample volume is required. We have applied this chemical metabolomics strategy for targeted SCFA analysis combined with global metabolomics on gut microbiome co-cultures with Salmonella and investigated the effect of antibiotic treatment.
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