1. Gene editing rescue of a novel MPL mutant associated with congenital amegakaryocytic thrombocytopenia
- Author
-
Eun Ho Eunice Choi, Thierry Lavabre-Bertrand, Cédric Cleyrat, Serge Carillo, Romain Girard, Sylvie Hermouet, Bridget S. Wilson, Eric Jeziorski, The University of New Mexico [Albuquerque], Département Pédiatrie [CHRU Montpellier], Pôle Femme Mère Enfant [CHRU Montpellier], Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier)-Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Laboratoire de Cytologie Clinique et de Cytogénétique [CHU Nîmes], Centre Hospitalier Universitaire de Nîmes (CHU Nîmes), Molecular Mechanisms of Chronic Inflammation in Hematological Diseases (CRCINA-ÉQUIPE 16), Centre de Recherche en Cancérologie et Immunologie Nantes-Angers (CRCINA), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA), This work was supported in part by grants from the Department of Defense, Congressionally Directed Medical Research Program (CA140409) (C.C. and B.S.W.), the American Cancer Society (126768-IRG-14-187-19) (C.C.), and Ligue contre le Cancer, comité du Gard (S.C.). Images in this paper were generated in the University of New Mexico (UNM) Cancer Center Fluorescence Microscopy Shared Resource supported by National Institutes of Health, National Cancer Institute (NCI) grant P30CA118110 and National Institutes of Health, National Institute of General Medical Science grant., Bernardo, Elizabeth, Institut des Biomolécules Max Mousseron [Pôle Chimie Balard] (IBMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université d'Angers (UA)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université d'Angers (UA)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes)
- Subjects
0301 basic medicine ,Mutation ,Mutant ,Hematopoietic stem cell ,[SDV.CAN]Life Sciences [q-bio]/Cancer ,Hematology ,Biology ,medicine.disease_cause ,medicine.disease ,Virology ,Molecular biology ,3. Good health ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,[SDV.CAN] Life Sciences [q-bio]/Cancer ,medicine ,biology.protein ,Congenital amegakaryocytic thrombocytopenia ,Thrombopoiesis ,Stem cell ,Calreticulin ,Thrombopoietin - Abstract
International audience; Thrombopoietin (Tpo) and its receptor (Mpl) are the principal regulators of early and late thrombopoiesis and hematopoietic stem cell maintenance. Mutations in MPL can drastically impair its function and be a contributing factor in multiple hematologic malignancies, including congenital amegakaryocytic thrombocytopenia (CAMT). CAMT is characterized by severe thrombocytopenia at birth, which progresses to bone marrow failure and pancytopenia. Here we report unique familial cases of CAMT that presented with a previously unreported MPL mutation: T814C (W272R) in the background of the activating MPL G117T (K39N or Baltimore) mutation. Confocal microscopy, proliferation and surface biotinylation assays, co-immunoprecipitation, and western blotting analysis were used to elucidate the function and trafficking of Mpl mutants. Results showed that Mpl protein bearing the W272R mutation, alone or together with the K39N mutation, lacks detectable surface expression while being strongly colocalized with the endoplasmic reticulum (ER) marker calreticulin. Both WT and K39N-mutated Mpl were found to be signaling competent, but single or double mutants bearing W272R were unresponsive to Tpo. Function of the deficient Mpl receptor could be rescued by using 2 separate approaches: (1) GRASP55 overexpression, which partially restored Tpo-induced signaling of mutant Mpl by activating an autophagy-dependent secretory pathway and thus forcing ER-trapped immature receptors to traffic to the cell surface; and (2) CRISPR-Cas9 gene editing used to repair MPL T814C mutation in transfected cell lines and primary umbilical cord blood–derived CD34+ cells. We demonstrate proof of principle for rescue of mutant Mpl function by using gene editing of primary hematopoietic stem cells, which indicates direct therapeutic applications for CAMT patients.
- Published
- 2017