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Morales-Hernández A, Benaksas C, Chabot A, Caprio C, Ferdous M, Zhao X, Kang G, McKinney-Freeman S. GPRASP proteins are critical negative regulators of hematopoietic stem cell transplantation. Blood 2020; 135:1111-1123. [PMID: 32027737 PMCID: PMC7118811 DOI: 10.1182/blood.2019003435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/21/2020] [Indexed: 11/20/2022] Open
Abstract
Hematopoietic stem cell (HSC) transplantation (HSCT) is often exploited to treat hematologic disease. Donor HSCs must survive, proliferate, and differentiate in the damaged environment of the reconstituting niche. Illuminating molecular mechanisms regulating the activity of transplanted HSCs will inform efforts to improve HSCT. Here, we report that G-protein-coupled receptor-associated sorting proteins (GPRASPs) function as negative regulators of HSCT. Silencing of Gprasp1 or Gprasp2 increased the survival, quiescence, migration, niche retention, and hematopoietic repopulating activity of hematopoietic stem and progenitor cells (HSPCs) posttransplant. We further show that GPRASP1 and GPRASP2 promote the degradation of CXCR4, a master regulator of HSC function during transplantation. CXCR4 accumulates in Gprasp-deficient HSPCs, boosting their function posttransplant. Thus, GPRASPs negatively regulate CXCR4 stability in HSCs. Our work reveals GPRASP proteins as negative regulators of HSCT and CXCR4 activity. Disruption of GPRASP/CXCR4 interactions could be exploited in the future to enhance the efficiency of HSCT.
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Affiliation(s)
| | - Chaïma Benaksas
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN
- Paris Diderot University, Paris, France; and
| | - Ashley Chabot
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN
| | - Claire Caprio
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN
| | - Maheen Ferdous
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN
| | - Xiwen Zhao
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN
| | - Guolian Kang
- Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, TN
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Saygin D, Tabib T, Bittar HET, Valenzi E, Sembrat J, Chan SY, Rojas M, Lafyatis R. Transcriptional profiling of lung cell populations in idiopathic pulmonary arterial hypertension. Pulm Circ 2020; 10:10.1177_2045894020908782. [PMID: 32166015 PMCID: PMC7052475 DOI: 10.1177/2045894020908782] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 01/29/2020] [Indexed: 12/13/2022] Open
Abstract
Despite recent improvements in management of idiopathic pulmonary arterial
hypertension, mortality remains high. Understanding the alterations in the
transcriptome–phenotype of the key lung cells involved could provide insight
into the drivers of pathogenesis. In this study, we examined differential gene
expression of cell types implicated in idiopathic pulmonary arterial
hypertension from lung explants of patients with idiopathic pulmonary arterial
hypertension compared to control lungs. After tissue digestion, we analyzed all
cells from three idiopathic pulmonary arterial hypertension and six control
lungs using droplet-based single cell RNA-sequencing. After dimensional
reduction by t-stochastic neighbor embedding, we compared the transcriptomes of
endothelial cells, pericyte/smooth muscle cells, fibroblasts, and macrophage
clusters, examining differential gene expression and pathways implicated by
analysis of Gene Ontology Enrichment. We found that endothelial cells and
pericyte/smooth muscle cells had the most differentially expressed gene profile
compared to other cell types. Top differentially upregulated genes in
endothelial cells included novel genes: ROBO4, APCDD1, NDST1, MMRN2,
NOTCH4, and DOCK6, as well as previously reported
genes: ENG, ORAI2, TFDP1, KDR, AMOTL2, PDGFB, FGFR1, EDN1, and
NOTCH1. Several transcription factors were also found to be
upregulated in idiopathic pulmonary arterial hypertension endothelial cells
including SOX18, STRA13, LYL1, and ELK, which
have known roles in regulating endothelial cell phenotype. In particular,
SOX18 was implicated through bioinformatics analyses in
regulating the idiopathic pulmonary arterial hypertension endothelial cell
transcriptome. Furthermore, idiopathic pulmonary arterial hypertension
endothelial cells upregulated expression of FAM60A and
HDAC7, potentially affecting epigenetic changes in
idiopathic pulmonary arterial hypertension endothelial cells. Pericyte/smooth
muscle cells expressed genes implicated in regulation of cellular apoptosis and
extracellular matrix organization, and several ligands for genes showing
increased expression in endothelial cells. In conclusion, our study represents
the first detailed look at the transcriptomic landscape across idiopathic
pulmonary arterial hypertension lung cells and provides robust insight into
alterations that occur in vivo in idiopathic pulmonary arterial hypertension
lungs.
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Affiliation(s)
- Didem Saygin
- Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Tracy Tabib
- Division of Rheumatology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Humberto E T Bittar
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Eleanor Valenzi
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - John Sembrat
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Stephen Y Chan
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Mauricio Rojas
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Robert Lafyatis
- Division of Rheumatology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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