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Kharrat M, Triki C, Ben Isaa A, Bouchaala W, Alila O, Chouchen J, Ghouliya Y, Kamoun F, Tlili A, Fakhfakh F. Expanding the genetic and phenotypic spectrum of TRAPPC9 and MID2-related neurodevelopmental disabilities: report of two novel mutations, 3D-modelling, and molecular docking studies. J Hum Genet 2024; 69:291-299. [PMID: 38467738 DOI: 10.1038/s10038-024-01242-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/13/2024]
Abstract
Intellectual disabilities (ID) and autism spectrum disorders (ASD) have a variety of etiologies, including environmental and genetic factors. Our study reports a psychiatric clinical investigation and a molecular analysis using whole exome sequencing (WES) of two siblings with ID and ASD from a consanguineous family. Bioinformatic prediction and molecular docking analysis were also carried out. The two patients were diagnosed with profound intellectual disability, brain malformations such as cortical atrophy, acquired microcephaly, and autism level III. The neurological and neuropsychiatric examination revealed that P2 was more severely affected than P1, as he was unable to walk, presented with dysmorphic feature and exhibited self and hetero aggressive behaviors. The molecular investigations revealed a novel TRAPPC9 biallelic nonsense mutation (c.2920 C > T, p.R974X) in the two siblings. The more severely affected patient (P2) presented, along with the TRAPPC9 variant, a new missense mutation c.166 C > T (p.R56C) in the MID2 gene at hemizygous state, while his sister P1 was merely a carrier. The 3D modelling and molecular docking analysis revealed that c.166 C > T variant could affect the ability of MID2 binding to Astrin, leading to dysregulation of microtubule dynamics and causing morphological abnormalities in the brain. As our knowledge, the MID2 mutation (p.R56C) is the first one to be detected in Tunisia and causing phenotypic variability between the siblings. We extend the genetic and clinical spectrum of TRAPPC9 and MID2 mutations and highlights the possible concomitant presence of X-linked as well as autosomal recessive inheritance to causing ID, microcephaly, and autism.
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Affiliation(s)
- Marwa Kharrat
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences of Sfax University, Sfax, Tunisia.
| | - Chahnez Triki
- Child Neurology Department, Hedi Chaker Hospital, Sfax, Tunisia
- Research laboratory (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
| | - Abir Ben Isaa
- Child Neurology Department, Hedi Chaker Hospital, Sfax, Tunisia
- Research laboratory (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
| | - Wafa Bouchaala
- Child Neurology Department, Hedi Chaker Hospital, Sfax, Tunisia
- Research laboratory (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
| | - Olfa Alila
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences of Sfax University, Sfax, Tunisia
| | - Jihen Chouchen
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Yosra Ghouliya
- Child Neurology Department, Hedi Chaker Hospital, Sfax, Tunisia
- Research laboratory (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
| | - Fatma Kamoun
- Child Neurology Department, Hedi Chaker Hospital, Sfax, Tunisia
- Research laboratory (LR19ES15), Sfax Medical School, Sfax University, Sfax, Tunisia
| | - Abdelaziz Tlili
- Department of Applied Biology, College of Sciences, University of Sharjah, Sharjah, United Arab Emirates
| | - Faiza Fakhfakh
- Laboratory of Molecular and Functional Genetics, Faculty of Sciences of Sfax University, Sfax, Tunisia.
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Li Y, Usman M, Sapp E, Ke Y, Wang Z, Boudi A, DiFiglia M, Li X. Chronic pharmacologic manipulation of dopamine transmission ameliorates metabolic disturbance in Trappc9-linked brain developmental syndrome. JCI Insight 2024; 9:e181339. [PMID: 38889014 PMCID: PMC11383600 DOI: 10.1172/jci.insight.181339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024] Open
Abstract
Loss-of-function mutations of the gene encoding the trafficking protein particle complex subunit 9 (Trappc9) cause autosomal recessive intellectual disability and obesity by unknown mechanisms. Genome-wide analysis links Trappc9 to nonalcoholic fatty liver disease (NAFLD). Trappc9-deficient mice have been shown to appear overweight shortly after weaning. Here, we analyzed serum biochemistry and histology of adipose and liver tissues to determine the incidence of obesity and NAFLD in Trappc9-deficient mice and combined transcriptomic and proteomic analyses, pharmacological studies, and biochemical and histological examinations of postmortem mouse brains to unveil mechanisms involved. We found that Trappc9-deficient mice presented with systemic glucose homeostatic disturbance, obesity, and NAFLD, which were relieved upon chronic treatment combining dopamine receptor D2 (DRD2) agonist quinpirole and DRD1 antagonist SCH23390. Blood glucose homeostasis in Trappc9-deficient mice was restored upon administering quinpirole alone. RNA-sequencing analysis of DRD2-containing neurons and proteomic study of brain synaptosomes revealed signs of impaired neurotransmitter secretion in Trappc9-deficient mice. Biochemical and histological studies of mouse brains showed that Trappc9-deficient mice synthesized dopamine normally, but their dopamine-secreting neurons had a lower abundance of structures for releasing dopamine in the striatum. Our study suggests that Trappc9 loss of function causes obesity and NAFLD by constraining dopamine synapse formation.
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Affiliation(s)
- Yan Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Muhammad Usman
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Yuting Ke
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Zejian Wang
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Adel Boudi
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
| | - Xueyi Li
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
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Aljuraysi S, Platt M, Pulix M, Poptani H, Plagge A. Microcephaly with a disproportionate hippocampal reduction, stem cell loss and neuronal lipid droplet symptoms in Trappc9 KO mice. Neurobiol Dis 2024; 192:106431. [PMID: 38331351 DOI: 10.1016/j.nbd.2024.106431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/23/2024] [Accepted: 02/04/2024] [Indexed: 02/10/2024] Open
Abstract
Mutations of the human TRAFFICKING PROTEIN PARTICLE COMPLEX SUBUNIT 9 (TRAPPC9) cause a neurodevelopmental disorder characterised by microcephaly and intellectual disability. Trappc9 constitutes a subunit specific to the intracellular membrane-associated TrappII complex. The TrappII complex interacts with Rab11 and Rab18, the latter being specifically associated with lipid droplets (LDs). Here we used non-invasive imaging to characterise Trappc9 knock-out (KO) mice as a model of the human hereditary disorder. KOs developed postnatal microcephaly with many grey and white matter regions being affected. In vivo magnetic resonance imaging (MRI) identified a disproportionately stronger volume reduction in the hippocampus, which was associated with a significant loss of Sox2-positive neural stem and progenitor cells. Diffusion tensor imaging indicated a reduced organisation or integrity of white matter areas. Trappc9 KOs displayed behavioural abnormalities in several tests related to exploration, learning and memory. Trappc9-deficient primary hippocampal neurons accumulated a larger LD volume per cell following Oleic Acid stimulation, and the coating of LDs by Perilipin-2 was much reduced. Additionally, Trappc9 KOs developed obesity, which was significantly more severe in females than in males. Our findings indicate that, beyond previously reported Rab11-related vesicle transport defects, dysfunctions in LD homeostasis might contribute to the neurobiological symptoms of Trappc9 deficiency.
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Affiliation(s)
- Sultan Aljuraysi
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mark Platt
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK
| | - Michela Pulix
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Harish Poptani
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK.
| | - Antonius Plagge
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Centre for Preclinical Imaging, University of Liverpool, Liverpool, UK.
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Hu M, Bodnar B, Zhang Y, Xie F, Li F, Li S, Zhao J, Zhao R, Gedupoori N, Mo Y, Lin L, Li X, Meng W, Yang X, Wang H, Barbe MF, Srinivasan S, Bethea JR, Mo X, Xu H, Hu W. Defective neurite elongation and branching in Nibp/Trappc9 deficient zebrafish and mice. Int J Biol Sci 2023; 19:3226-3248. [PMID: 37416774 PMCID: PMC10321293 DOI: 10.7150/ijbs.78489] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 06/06/2023] [Indexed: 07/08/2023] Open
Abstract
Loss of function in transport protein particles (TRAPP) links a new set of emerging genetic disorders called "TRAPPopathies". One such disorder is NIBP syndrome, characterized by microcephaly and intellectual disability, and caused by mutations of NIBP/TRAPPC9, a crucial and unique member of TRAPPII. To investigate the neural cellular/molecular mechanisms underlying microcephaly, we developed Nibp/Trappc9-deficient animal models using different techniques, including morpholino knockdown and CRISPR/Cas mutation in zebrafish and Cre/LoxP-mediated gene targeting in mice. Nibp/Trappc9 deficiency impaired the stability of the TRAPPII complex at actin filaments and microtubules of neurites and growth cones. This deficiency also impaired elongation and branching of neuronal dendrites and axons, without significant effects on neurite initiation or neural cell number/types in embryonic and adult brains. The positive correlation of TRAPPII stability and neurite elongation/branching suggests a potential role for TRAPPII in regulating neurite morphology. These results provide novel genetic/molecular evidence to define patients with a type of non-syndromic autosomal recessive intellectual disability and highlight the importance of developing therapeutic approaches targeting the TRAPPII complex to cure TRAPPopathies.
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Affiliation(s)
- Min Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Brittany Bodnar
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yonggang Zhang
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
| | - Fangxin Xie
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu 610052, China
- Department of Clinical Laboratory, Xi'an NO. 3 Hospital, Xi'an, Shaanxi, 710018, China
| | - Fang Li
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Siying Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Jin Zhao
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Ruotong Zhao
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Naveen Gedupoori
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Yifan Mo
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Lanyi Lin
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Xue Li
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wentong Meng
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Xiaofeng Yang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Hong Wang
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Mary F. Barbe
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Shanthi Srinivasan
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - John R. Bethea
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Hong Xu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
| | - Wenhui Hu
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, China
- Center for Metabolic Disease Research, Department of Pathalogy and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
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