Naturally occurring variations in the human 5-HT3A gene profoundly impact 5-HT3 receptor function and expression

Karen Krzywkowski, Anders A. Jensen, Christopher N. Connolly, Hans Brauner-Osborne

    Research output: Contribution to journalArticle

    32 Citations (Scopus)

    Abstract

    Background The serotonin [5-hydroxytryptamine (5-HT)]-gated ion channel 5-HT3 is involved in the mediation of postoperative and radiotherapy/chemotherapy-induced nausea/emesis and in irritable bowel syndrome. It has also been suggested to play a role in various psychiatric diseases. Five naturally occurring single nucleotide polymorphisms leading to amino acid changes have been identified in the human 5-HT3A gene.

    Methods and results We investigated the functional effects of these polymorphisms on the 5-HT3A receptor using fluorescence-based cellular assays. Notably, variants A33T, S253N, and M257I displayed 5-HT-induced maximal responses of 3-64% of the wild-type response, whereas R344H and P391R exhibited wild-type-like function. All variants displayed wild-type-like potencies of 5-HT and three 5-HT3 antagonists. Furthermore, all variants displayed K-d values similar to that of the wild-type receptor in a [H-3]GR65630-binding assay. The surface expression of A33T, M2571, and R344H was reduced 2-4-fold compared with the wild-type, despite similar total expression levels. Finally, coexpression of wild-type 5-HT3A or 5-HT3B subunits with 5-HT3A variants A33T, S253N, or M257I resulted in mixed or heteromeric receptors, characterized by significantly reduced maximal responses to 5-HT compared with the wild-type receptors.

    Conclusions Three polymorphisms of the 5-HT3A gene gave rise to functionally impaired receptors whose function could not be rescued by either wild-type 5-HT3A or 5-HT3B. Three of the variant receptors were surface-expressed at reduced levels in spite of total expression levels similar to wild-type, indicating that these variants affect receptor biogenesis and/or trafficking. These severe single nucleotide polymorphism effects hold promise for identification of new 5-HT3A gene-disease causalities.

    Original languageEnglish
    Pages (from-to)255-266
    Number of pages12
    JournalPharmacogenetics and Genomics
    Volume17
    Issue number4
    DOIs
    Publication statusPublished - Apr 2007

    Cite this

    @article{5c241ff0566444db8de42b8d752db264,
    title = "Naturally occurring variations in the human 5-HT3A gene profoundly impact 5-HT3 receptor function and expression",
    abstract = "Background The serotonin [5-hydroxytryptamine (5-HT)]-gated ion channel 5-HT3 is involved in the mediation of postoperative and radiotherapy/chemotherapy-induced nausea/emesis and in irritable bowel syndrome. It has also been suggested to play a role in various psychiatric diseases. Five naturally occurring single nucleotide polymorphisms leading to amino acid changes have been identified in the human 5-HT3A gene.Methods and results We investigated the functional effects of these polymorphisms on the 5-HT3A receptor using fluorescence-based cellular assays. Notably, variants A33T, S253N, and M257I displayed 5-HT-induced maximal responses of 3-64{\%} of the wild-type response, whereas R344H and P391R exhibited wild-type-like function. All variants displayed wild-type-like potencies of 5-HT and three 5-HT3 antagonists. Furthermore, all variants displayed K-d values similar to that of the wild-type receptor in a [H-3]GR65630-binding assay. The surface expression of A33T, M2571, and R344H was reduced 2-4-fold compared with the wild-type, despite similar total expression levels. Finally, coexpression of wild-type 5-HT3A or 5-HT3B subunits with 5-HT3A variants A33T, S253N, or M257I resulted in mixed or heteromeric receptors, characterized by significantly reduced maximal responses to 5-HT compared with the wild-type receptors.Conclusions Three polymorphisms of the 5-HT3A gene gave rise to functionally impaired receptors whose function could not be rescued by either wild-type 5-HT3A or 5-HT3B. Three of the variant receptors were surface-expressed at reduced levels in spite of total expression levels similar to wild-type, indicating that these variants affect receptor biogenesis and/or trafficking. These severe single nucleotide polymorphism effects hold promise for identification of new 5-HT3A gene-disease causalities.",
    author = "Karen Krzywkowski and Jensen, {Anders A.} and Connolly, {Christopher N.} and Hans Brauner-Osborne",
    year = "2007",
    month = "4",
    doi = "10.1097/FPC.0b013e3280117269",
    language = "English",
    volume = "17",
    pages = "255--266",
    journal = "Pharmacogenetics and Genomics",
    issn = "1744-6872",
    publisher = "Lippincott, Williams & Wilkins",
    number = "4",

    }

    Naturally occurring variations in the human 5-HT3A gene profoundly impact 5-HT3 receptor function and expression. / Krzywkowski, Karen; Jensen, Anders A.; Connolly, Christopher N.; Brauner-Osborne, Hans.

    In: Pharmacogenetics and Genomics, Vol. 17, No. 4, 04.2007, p. 255-266.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Naturally occurring variations in the human 5-HT3A gene profoundly impact 5-HT3 receptor function and expression

    AU - Krzywkowski, Karen

    AU - Jensen, Anders A.

    AU - Connolly, Christopher N.

    AU - Brauner-Osborne, Hans

    PY - 2007/4

    Y1 - 2007/4

    N2 - Background The serotonin [5-hydroxytryptamine (5-HT)]-gated ion channel 5-HT3 is involved in the mediation of postoperative and radiotherapy/chemotherapy-induced nausea/emesis and in irritable bowel syndrome. It has also been suggested to play a role in various psychiatric diseases. Five naturally occurring single nucleotide polymorphisms leading to amino acid changes have been identified in the human 5-HT3A gene.Methods and results We investigated the functional effects of these polymorphisms on the 5-HT3A receptor using fluorescence-based cellular assays. Notably, variants A33T, S253N, and M257I displayed 5-HT-induced maximal responses of 3-64% of the wild-type response, whereas R344H and P391R exhibited wild-type-like function. All variants displayed wild-type-like potencies of 5-HT and three 5-HT3 antagonists. Furthermore, all variants displayed K-d values similar to that of the wild-type receptor in a [H-3]GR65630-binding assay. The surface expression of A33T, M2571, and R344H was reduced 2-4-fold compared with the wild-type, despite similar total expression levels. Finally, coexpression of wild-type 5-HT3A or 5-HT3B subunits with 5-HT3A variants A33T, S253N, or M257I resulted in mixed or heteromeric receptors, characterized by significantly reduced maximal responses to 5-HT compared with the wild-type receptors.Conclusions Three polymorphisms of the 5-HT3A gene gave rise to functionally impaired receptors whose function could not be rescued by either wild-type 5-HT3A or 5-HT3B. Three of the variant receptors were surface-expressed at reduced levels in spite of total expression levels similar to wild-type, indicating that these variants affect receptor biogenesis and/or trafficking. These severe single nucleotide polymorphism effects hold promise for identification of new 5-HT3A gene-disease causalities.

    AB - Background The serotonin [5-hydroxytryptamine (5-HT)]-gated ion channel 5-HT3 is involved in the mediation of postoperative and radiotherapy/chemotherapy-induced nausea/emesis and in irritable bowel syndrome. It has also been suggested to play a role in various psychiatric diseases. Five naturally occurring single nucleotide polymorphisms leading to amino acid changes have been identified in the human 5-HT3A gene.Methods and results We investigated the functional effects of these polymorphisms on the 5-HT3A receptor using fluorescence-based cellular assays. Notably, variants A33T, S253N, and M257I displayed 5-HT-induced maximal responses of 3-64% of the wild-type response, whereas R344H and P391R exhibited wild-type-like function. All variants displayed wild-type-like potencies of 5-HT and three 5-HT3 antagonists. Furthermore, all variants displayed K-d values similar to that of the wild-type receptor in a [H-3]GR65630-binding assay. The surface expression of A33T, M2571, and R344H was reduced 2-4-fold compared with the wild-type, despite similar total expression levels. Finally, coexpression of wild-type 5-HT3A or 5-HT3B subunits with 5-HT3A variants A33T, S253N, or M257I resulted in mixed or heteromeric receptors, characterized by significantly reduced maximal responses to 5-HT compared with the wild-type receptors.Conclusions Three polymorphisms of the 5-HT3A gene gave rise to functionally impaired receptors whose function could not be rescued by either wild-type 5-HT3A or 5-HT3B. Three of the variant receptors were surface-expressed at reduced levels in spite of total expression levels similar to wild-type, indicating that these variants affect receptor biogenesis and/or trafficking. These severe single nucleotide polymorphism effects hold promise for identification of new 5-HT3A gene-disease causalities.

    U2 - 10.1097/FPC.0b013e3280117269

    DO - 10.1097/FPC.0b013e3280117269

    M3 - Article

    VL - 17

    SP - 255

    EP - 266

    JO - Pharmacogenetics and Genomics

    JF - Pharmacogenetics and Genomics

    SN - 1744-6872

    IS - 4

    ER -