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  1. Article ; Online: CAMAP

    Tariq Daouda / Maude Dumont-Lagacé / Albert Feghaly / Yahya Benslimane / Rébecca Panes / Mathieu Courcelles / Mohamed Benhammadi / Lea Harrington / Pierre Thibault / François Major / Yoshua Bengio / Étienne Gagnon / Sébastien Lemieux / Claude Perreault

    PLoS Computational Biology, Vol 17, Iss

    Artificial neural networks unveil the role of codon arrangement in modulating MHC-I peptides presentation

    2021  Volume 10

    Abstract: MHC-I associated peptides (MAPs) play a central role in the elimination of virus-infected and neoplastic cells by CD8 T cells. However, accurately predicting the MAP repertoire remains difficult, because only a fraction of the transcriptome generates ... ...

    Abstract MHC-I associated peptides (MAPs) play a central role in the elimination of virus-infected and neoplastic cells by CD8 T cells. However, accurately predicting the MAP repertoire remains difficult, because only a fraction of the transcriptome generates MAPs. In this study, we investigated whether codon arrangement (usage and placement) regulates MAP biogenesis. We developed an artificial neural network called Codon Arrangement MAP Predictor (CAMAP), predicting MAP presentation solely from mRNA sequences flanking the MAP-coding codons (MCCs), while excluding the MCC per se. CAMAP predictions were significantly more accurate when using original codon sequences than shuffled codon sequences which reflect amino acid usage. Furthermore, predictions were independent of mRNA expression and MAP binding affinity to MHC-I molecules and applied to several cell types and species. Combining MAP ligand scores, transcript expression level and CAMAP scores was particularly useful to increase MAP prediction accuracy. Using an in vitro assay, we showed that varying the synonymous codons in the regions flanking the MCCs (without changing the amino acid sequence) resulted in significant modulation of MAP presentation at the cell surface. Taken together, our results demonstrate the role of codon arrangement in the regulation of MAP presentation and support integration of both translational and post-translational events in predictive algorithms to ameliorate modeling of the immunopeptidome. Author summary MHC-I associated peptides (MAPs) are small fragments of intracellular proteins presented at the surface of cells and used by the immune system to detect and eliminate cancerous or virus-infected cells. While it is theoretically possible to predict which portions of the intracellular proteins will be naturally processed by the cells to ultimately reach the surface, current methodologies have prohibitively high false discovery rates. Here we introduce an artificial neural network called Codon Arrangement MAP Predictor (CAMAP) which ...
    Keywords Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2021-10-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: CAMAP

    Tariq Daouda / Maude Dumont-Lagacé / Albert Feghaly / Yahya Benslimane / Rébecca Panes / Mathieu Courcelles / Mohamed Benhammadi / Lea Harrington / Pierre Thibault / François Major / Yoshua Bengio / Étienne Gagnon / Sébastien Lemieux / Claude Perreault

    PLoS Computational Biology, Vol 17, Iss 10, p e

    Artificial neural networks unveil the role of codon arrangement in modulating MHC-I peptides presentation.

    2021  Volume 1009482

    Abstract: MHC-I associated peptides (MAPs) play a central role in the elimination of virus-infected and neoplastic cells by CD8 T cells. However, accurately predicting the MAP repertoire remains difficult, because only a fraction of the transcriptome generates ... ...

    Abstract MHC-I associated peptides (MAPs) play a central role in the elimination of virus-infected and neoplastic cells by CD8 T cells. However, accurately predicting the MAP repertoire remains difficult, because only a fraction of the transcriptome generates MAPs. In this study, we investigated whether codon arrangement (usage and placement) regulates MAP biogenesis. We developed an artificial neural network called Codon Arrangement MAP Predictor (CAMAP), predicting MAP presentation solely from mRNA sequences flanking the MAP-coding codons (MCCs), while excluding the MCC per se. CAMAP predictions were significantly more accurate when using original codon sequences than shuffled codon sequences which reflect amino acid usage. Furthermore, predictions were independent of mRNA expression and MAP binding affinity to MHC-I molecules and applied to several cell types and species. Combining MAP ligand scores, transcript expression level and CAMAP scores was particularly useful to increase MAP prediction accuracy. Using an in vitro assay, we showed that varying the synonymous codons in the regions flanking the MCCs (without changing the amino acid sequence) resulted in significant modulation of MAP presentation at the cell surface. Taken together, our results demonstrate the role of codon arrangement in the regulation of MAP presentation and support integration of both translational and post-translational events in predictive algorithms to ameliorate modeling of the immunopeptidome.
    Keywords Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2021-10-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Immunoproteasomes Control the Homeostasis of Medullary Thymic Epithelial Cells by Alleviating Proteotoxic Stress

    Charles St-Pierre / Erwan Morgand / Mohamed Benhammadi / Alexandre Rouette / Marie-Pierre Hardy / Louis Gaboury / Claude Perreault

    Cell Reports, Vol 21, Iss 9, Pp 2558-

    2017  Volume 2570

    Abstract: The sole nonredundant role of the thymic medulla is to induce central tolerance, a vital process that depends on promiscuous gene expression (pGE), a unique feature of medullary thymic epithelial cells (mTECs). Although pGE enhances transcription of >3, ... ...

    Abstract The sole nonredundant role of the thymic medulla is to induce central tolerance, a vital process that depends on promiscuous gene expression (pGE), a unique feature of medullary thymic epithelial cells (mTECs). Although pGE enhances transcription of >3,000 genes in mTECs, its impact on the regulation of protein homeostasis remains unexplored. Here, we report that, because of pGE, mature mTECs synthesize substantially more proteins than other cell types and are exquisitely sensitive to loss of immunoproteasomes (IPs). Indeed, IP deficiency causes proteotoxic stress in mTECs and leads to exhaustion of postnatal mTEC progenitors. Moreover, IP-deficient mice show accelerated thymic involution, which is characterized by a selective loss of mTECs and multiorgan autoimmune manifestations. We conclude that pGE, the quintessential feature of mTECs, is a major burden for the maintenance of proteostasis, which is alleviated by the constitutive expression of IPs in mTECs.
    Keywords thymic epithelial cells ; thymic involution ; self-tolerance ; promiscuous gene expression ; immunoproteasomes ; proteotoxic stress ; autoimmunity ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2017-11-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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