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Hernandez RA, Hearn JI, Bhoopalan V, Hamzeh AR, Kwong K, Diamand K, Davies A, Li FJ, Padmanabhan H, Milne R, Ballard F, Spensberger D, Gardiner EE, Miraghazadeh B, Enders A, Cook MC. L-plastin associated syndrome of immune deficiency and hematologic cytopenia. J Allergy Clin Immunol 2024; 154:767-777. [PMID: 38710235 DOI: 10.1016/j.jaci.2024.05.001] [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: 11/01/2023] [Revised: 04/01/2024] [Accepted: 05/01/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND LCP1 encodes L-plastin, an actin-bundling protein primarily expressed in hematopoietic cells. In mouse and fish models, LCP1 deficiency has been shown to result in hematologic and immune defects. OBJECTIVE This study aimed to determine the nature of a human inborn error of immunity resulting from a novel genetic variant of LCP1. METHODS We performed genetic, protein, and cellular analysis of PBMCs from a kindred with apparent autosomal dominant immune deficiency. We identified a candidate causal mutation in LCP1, which we evaluated by engineering the orthologous mutation in mice and Jurkat cells. RESULTS A splice-site variant in LCP1 segregated with lymphopenia, neutropenia, and thrombocytopenia. The splicing defect resulted in at least 2 aberrant transcripts, producing an in-frame deletion of 24 nucleotides, and a frameshift deletion of exon 8. Cellular analysis of the kindred revealed a proportionate reduction of T and B cells and a mild expansion of transitional B cells. Similarly, mice carrying the orthologous genetic variant exhibited the same in-frame aberrant transcript, reduced expression Lcp1 and gene dose-dependent leukopenia, mild thrombocytopenia, and lymphopenia, with a significant reduction of T-cell populations. Functional analysis revealed that LCP1c740-1G>A confers a defect in platelet development and function with aberrant spreading on collagen. Immunologic analysis revealed defective actin organization in T cells, reduced migration of PBMCs from patients, splenocytes from mutant mice, and a mutant Jurkat cell line in response to CXCL12; impaired germinal center B-cell expansion after immunization; and reduced cytokinesis during T cell proliferation. CONCLUSIONS We describe a unique human hematopoietic defect affecting neutrophils, lymphocytes, and platelets arising from partial LCP1 deficiency.
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Affiliation(s)
- Raquel A Hernandez
- Division of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - James I Hearn
- Division of Genome Sciences and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Vijay Bhoopalan
- Division of Genome Sciences and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | | | - Kristy Kwong
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia; Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Koula Diamand
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Ainsley Davies
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Fei-Ju Li
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Harish Padmanabhan
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Rachel Milne
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Fiona Ballard
- Division of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Dominik Spensberger
- Australian Phenomics Facility and John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Elizabeth E Gardiner
- Division of Genome Sciences and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Bahar Miraghazadeh
- Division of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Anselm Enders
- Division of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Matthew C Cook
- Division of Immunology and Infectious Diseases, John Curtin School of Medical Research, Australian National University, Canberra, Australia; Canberra Clinical Genomics, Canberra, Australia; Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, University of Cambridge, Cambridge, United Kingdom.
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Cao L, Huang S, Basant A, Mladenov M, Way M. CK-666 and CK-869 differentially inhibit Arp2/3 iso-complexes. EMBO Rep 2024; 25:3221-3239. [PMID: 39009834 PMCID: PMC11316031 DOI: 10.1038/s44319-024-00201-x] [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: 03/22/2024] [Revised: 05/30/2024] [Accepted: 06/18/2024] [Indexed: 07/17/2024] Open
Abstract
The inhibitors, CK-666 and CK-869, are widely used to probe the function of Arp2/3 complex mediated actin nucleation in vitro and in cells. However, in mammals, the Arp2/3 complex consists of 8 iso-complexes, as three of its subunits (Arp3, ArpC1, ArpC5) are encoded by two different genes. Here, we used recombinant Arp2/3 with defined composition to assess the activity of CK-666 and CK-869 against iso-complexes. We demonstrate that both inhibitors prevent linear actin filament formation when ArpC1A- or ArpC1B-containing complexes are activated by SPIN90. In contrast, inhibition of actin branching depends on iso-complex composition. Both drugs prevent actin branch formation by complexes containing ArpC1A, but only CK-869 can inhibit ArpC1B-containing complexes. Consistent with this, in bone marrow-derived macrophages which express low levels of ArpC1A, CK-869 but not CK-666, impacted phagocytosis and cell migration. CK-869 also only inhibits Arp3- but not Arp3B-containing iso-complexes. Our findings have important implications for the interpretation of results using CK-666 and CK-869, given that the relative expression levels of ArpC1 and Arp3 isoforms in cells and tissues remains largely unknown.
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Affiliation(s)
- LuYan Cao
- The Francis Crick Institute, London, UK.
| | | | | | | | - Michael Way
- The Francis Crick Institute, London, UK.
- Department of Infectious Disease, Imperial College, London, UK.
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Peterson A, Bennin D, Lasarev M, Chini J, Beebe DJ, Huttenlocher A. Neutrophil motility is regulated by both cell intrinsic and endothelial cell ARPC1B. J Cell Sci 2024; 137:jcs261774. [PMID: 38224139 PMCID: PMC10911274 DOI: 10.1242/jcs.261774] [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: 11/01/2023] [Accepted: 01/08/2024] [Indexed: 01/16/2024] Open
Abstract
Neutrophil-directed motility is necessary for host defense, but its dysregulation can also cause collateral tissue damage. Actinopathies are monogenic disorders that affect the actin cytoskeleton and lead to immune dysregulation. Deficiency in ARPC1B, a component of the Arp2/3 complex, results in vascular neutrophilic inflammation; however, the mechanism remains unclear. Here, we generated human induced pluripotent stem cell (iPSC)-derived neutrophils (denoted iNeutrophils) that are deficient in ARPC1B and show impaired migration and a switch from forming pseudopodia to forming elongated filopodia. We show, using a blood vessel on a chip model, that primary human neutrophils have impaired movement across an endothelium deficient in APRC1B. We also show that the combined deficiency of ARPC1B in iNeutrophils and endothelium results in further reduction in neutrophil migration. Taken together, these results suggest that ARPC1B in endothelium is sufficient to drive neutrophil behavior. Furthermore, the findings provide support for using the iPSC system to understand human neutrophil biology and model disease in a genetically tractable system.
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Affiliation(s)
- Ashley Peterson
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Comparative Biomedical Sciences Graduate Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - David Bennin
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Michael Lasarev
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI 53706, USA
| | - Julia Chini
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David J. Beebe
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA
- Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Anna Huttenlocher
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Pediatrics, University of Wisconsin-Madison, Madison, WI 53706, USA
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