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Inskeep KA, Crase B, Stottmann RW. SMPD4 mediated sphingolipid metabolism regulates brain and primary cilia development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571873. [PMID: 38168190 PMCID: PMC10760124 DOI: 10.1101/2023.12.15.571873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Genetic variants in multiple sphingolipid biosynthesis genes cause human brain disorders. A recent study collected patients from twelve unrelated families with variants in the gene SMPD4 , a neutral sphingomyelinase which metabolizes sphingomyelin into ceramide at an early stage of the biosynthesis pathway. These patients have severe developmental brain malformations including microcephaly and cerebellar hypoplasia. However, the mechanism of SMPD4 was not known and we pursued a new mouse model. We hypothesized that the role of SMPD4 in producing ceramide is important for making primary cilia, a crucial organelle mediating cellular signaling. We found that the mouse model has cerebellar hypoplasia due to failure of Purkinje cell development. Human induced pluripotent stem cells exhibit neural progenitor cell death and have shortened primary cilia which is rescued by adding exogenous ceramide. SMPD4 production of ceramide is crucial for human brain development.
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Gambadauro A, Mangano GD, Galletta K, Granata F, Riva A, Massella L, Guzzo I, Farello G, Scorrano G, Di Francesco L, Di Donato G, Ianni C, Di Ludovico A, La Bella S, Striano P, Efthymiou S, Houlden H, Nardello R, Chimenz R. NUP85 as a Neurodevelopmental Gene: From Podocyte to Neuron. Genes (Basel) 2023; 14:2143. [PMID: 38136965 PMCID: PMC10743110 DOI: 10.3390/genes14122143] [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: 10/10/2023] [Revised: 11/20/2023] [Accepted: 11/26/2023] [Indexed: 12/24/2023] Open
Abstract
Pathogenic gene variants encoding nuclear pore complex (NPC) proteins were previously implicated in the pathogenesis of steroid-resistant nephrotic syndrome (SRNS). The NUP85 gene, encoding nucleoporin, is related to a very rare form of SRNS with limited genotype-phenotype information. We identified an Italian boy affected with an SRNS associated with severe neurodevelopmental impairment characterized by microcephaly, axial hypotonia, lack of achievement of motor milestones, and refractory seizures with an associated hypsarrhythmic pattern on electroencephalography. Brain magnetic resonance imaging (MRI) showed hypoplasia of the corpus callosum and a simplified gyration of the cerebral cortex. Since the age of 3 years, the boy was followed up at our Pediatric Nephrology Department for an SRNS, with a focal segmental glomerulosclerosis at renal biopsy. The boy died 32 months after SRNS onset, and a Whole-Exome Sequencing analysis revealed a novel compound heterozygous variant in NUP85 (NM_024844.5): 611T>A (p.Val204Glu), c.1904T>G (p.Leu635Arg), inherited from the father and mother, respectively. We delineated the clinical phenotypes of NUP85-related disorders, reviewed the affected individuals so far reported in the literature, and overall expanded both the phenotypic and the molecular spectrum associated with this ultra-rare genetic condition. Our study suggests a potential occurrence of severe neurological phenotypes as part of the NUP85-related clinical spectrum and highlights an important involvement of nucleoporin in brain developmental processes and neurological function.
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Affiliation(s)
- Antonella Gambadauro
- Department of Human Pathology in Adult and Developmental Age “Gaetano Barresi”, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy; (A.G.); (R.C.)
| | - Giuseppe Donato Mangano
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
| | - Karol Galletta
- Department of Biomedical, Dental Science and Morphological and Functional Images, Neuroradiology Unit, University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy; (K.G.); (F.G.)
| | - Francesca Granata
- Department of Biomedical, Dental Science and Morphological and Functional Images, Neuroradiology Unit, University of Messina, Via Consolare Valeria 1, 98125 Messina, Italy; (K.G.); (F.G.)
| | - Antonella Riva
- Unit of Medical Genetics, IRCSS Giannina Gaslini Institute, Via Gerolamo Gaslini 5, 16147 Genoa, Italy; (A.R.); (P.S.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Via Gerolamo Gaslini 5, 16147 Genoa, Italy
| | - Laura Massella
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 00165 Rome, Italy; (L.M.); (I.G.)
| | - Isabella Guzzo
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), 00165 Rome, Italy; (L.M.); (I.G.)
| | - Giovanni Farello
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Giovanna Scorrano
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Ludovica Di Francesco
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Giulio Di Donato
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Carolina Ianni
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Armando Di Ludovico
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Saverio La Bella
- Department of Pediatrics, University of L’Aquila, 67100 L’Aquila, Italy; (G.F.); (G.S.); (L.D.F.); (G.D.D.); (C.I.); (A.D.L.)
| | - Pasquale Striano
- Unit of Medical Genetics, IRCSS Giannina Gaslini Institute, Via Gerolamo Gaslini 5, 16147 Genoa, Italy; (A.R.); (P.S.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Via Gerolamo Gaslini 5, 16147 Genoa, Italy
| | - Stephanie Efthymiou
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK; (S.E.); (H.H.)
| | - Henry Houlden
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK; (S.E.); (H.H.)
| | - Rosaria Nardello
- Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, 90127 Palermo, Italy;
| | - Roberto Chimenz
- Department of Human Pathology in Adult and Developmental Age “Gaetano Barresi”, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy; (A.G.); (R.C.)
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Jühlen R, Fahrenkrog B. From the sideline: Tissue-specific nucleoporin function in health and disease, an update. FEBS Lett 2023; 597:2750-2768. [PMID: 37873737 DOI: 10.1002/1873-3468.14761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/26/2023] [Accepted: 10/04/2023] [Indexed: 10/25/2023]
Abstract
The subcellular compartmentalisation of eukaryotic cells requires selective exchange between the cytoplasm and the nucleus. Intact nucleocytoplasmic transport is vital for normal cell function and mutations in the executing machinery have been causally linked to human disease. Central players in nucleocytoplasmic exchange are nuclear pore complexes (NPCs), which are built from ~30 distinct proteins collectively termed nucleoporins. Aberrant nucleoporin expression was detected in human cancers and autoimmune diseases since quite some time, while it was through the increasing use of next generation sequencing that mutations in nucleoporin genes associated with mainly rare hereditary diseases were revealed. The number of newly identified mutations is steadily increasing, as is the number of diseases. Mutational hotspots have emerged: mutations in the scaffold nucleoporins seemingly affect primarily inner organs, such as heart, kidney, and ovaries, whereas genetic alterations in peripheral, cytoplasmic nucleoporins affect primarily the central nervous system and development. In this review, we summarise latest insights on altered nucleoporin function in the context of human hereditary disorders, with a focus on those where mechanistic insights are beginning to emerge.
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Affiliation(s)
- Ramona Jühlen
- Institute of Biochemistry and Molecular Cell Biology, Medical School, RWTH Aachen University, Aachen, Germany
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