1
|
Renella R, Gagne K, Beauchamp E, Fogel J, Perlov A, Sola M, Schlaeger T, Hofmann I, Shimamura A, Ebert BL, Schmitz-Abe K, Markianos K, Murphy K, Sun L, Rockowitz S, Sliz P, Campagna DR, Springer TA, Bahl C, Agarwal S, Fleming MD, Williams DA. Congenital X-linked neutropenia with myelodysplasia and somatic tetraploidy due to a germline mutation in SEPT6. Am J Hematol 2022; 97:18-29. [PMID: 34677878 PMCID: PMC8671325 DOI: 10.1002/ajh.26382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 01/03/2023]
Abstract
Septins play key roles in mammalian cell division and cytokinesis but have not previously been implicated in a germline human disorder. A male infant with severe neutropenia and progressive dysmyelopoiesis with tetraploid myeloid precursors was identified. No known genetic etiologies for neutropenia or bone marrow failure were found. However, next-generation sequencing of germline samples from the patient revealed a novel, de novo germline stop-loss mutation in the X-linked gene SEPT6 that resulted in reduced SEPT6 staining in bone marrow granulocyte precursors and megakaryocytes. Patient skin fibroblast-derived induced pluripotent stem cells (iPSCs) produced reduced myeloid colonies, particularly of the granulocyte lineage. CRISPR/Cas9 knock-in of the patient's mutation or complete knock-out of SEPT6 was not tolerated in non-patient-derived iPSCs or human myeloid cell lines, but SEPT6 knock-out was successful in an erythroid cell line and resulting clones revealed a propensity to multinucleation. In silico analysis predicts that the mutated protein hinders the dimerization of SEPT6 coiled-coils in both parallel and antiparallel arrangements, which could in turn impair filament formation. These data demonstrate a critical role for SEPT6 in chromosomal segregation in myeloid progenitors that can account for the unusual predisposition to aneuploidy and dysmyelopoiesis.
Collapse
Affiliation(s)
- Raffaele Renella
- Pediatric Hematology-Oncology Research Laboratory, Lausanne University Hospital, Switzerland,Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Katelyn Gagne
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Ellen Beauchamp
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA
| | - Jonathan Fogel
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Aleksej Perlov
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Mireia Sola
- Institute for Protein Innovation, Boston, USA
| | - Thorsten Schlaeger
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Inga Hofmann
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA,Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, USA,Present address: Division of Pediatric Hematology-Oncology, University of Wisconsin School of Medicine, Madison, USA
| | - Akiko Shimamura
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Benjamin L Ebert
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, USA,Harvard Stem Cell Institute, Harvard Medical School, Boston, USA
| | - Klaus Schmitz-Abe
- Division of Newborn Medicine, Department of Pediatrics, Boston Children’s Hospital, Boston, USA
| | - Kyriacos Markianos
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, USA
| | - Kristi Murphy
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, USA
| | - Liang Sun
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, USA
| | - Shira Rockowitz
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, USA
| | - Piotr Sliz
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, USA,Division of Molecular Medicine, Boston Children’s Hospital, Boston, USA
| | - Dean R Campagna
- Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - Timothy A Springer
- Program in Cellular & Molecular Medicine, Boston Children’s Hospital, Boston, USA,Institute for Protein Innovation, Boston, USA
| | - Christopher Bahl
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA,Institute for Protein Innovation, Boston, USA
| | - Suneet Agarwal
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA,Harvard Stem Cell Institute, Harvard Medical School, Boston, USA
| | - Mark D Fleming
- Department of Pathology, Boston Children’s Hospital, Harvard Medical School, Boston, USA
| | - David A Williams
- Division of Hematology-Oncology, Boston Children’s Hospital, Harvard Medical School, Boston, USA,Harvard Stem Cell Institute, Harvard Medical School, Boston, USA
| |
Collapse
|
3
|
Septins are critical regulators of osteoclastic bone resorption. Sci Rep 2018; 8:13016. [PMID: 30158637 PMCID: PMC6115361 DOI: 10.1038/s41598-018-31159-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/07/2018] [Indexed: 12/23/2022] Open
Abstract
Septins are known to play key roles in supporting cytoskeletal stability, vesicular transport, endo-/exocytosis, stabilizing cellular membranes and forming diffusion barriers. Their function in mammalian cells is poorly investigated. The osteoclast offers an interesting tool to investigate septins because all cellular activities septins were reported to be involved in are critical for osteoclasts. However, the existence of septins in osteoclasts has not even been reported. Here we show that the SEPT9 gene and Septin 9 (SEPT9) protein are expressed and synthesized during differentiation of human osteoclasts. Pharmacological stabilization of septin filaments dose dependently inhibits bone resorption of human osteoclasts in vitro suggesting a role for septins in bone resorption. Attesting to this, conditional deletion of Sept9 in mice leads to elevated levels of trabecular bone and diminished femoral growth in vivo. Finally, systematic interrogation of the spatial organization of SEPT9 by confocal microscopy reveals that SEPT9 is closely associated to the structures known to be critical for osteoclast activity. We propose that septins in general and SEPT9 in particular play a previously unappreciated role in osteoclastic bone resorption.
Collapse
|