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Moses A, Bhalla P, Thompson A, Lai L, Coskun FS, Seroogy CM, de la Morena MT, Wysocki CA, van Oers NSC. Comprehensive phenotypic analysis of diverse FOXN1 variants. J Allergy Clin Immunol 2023; 152:1273-1291.e15. [PMID: 37419334 PMCID: PMC11071152 DOI: 10.1016/j.jaci.2023.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 05/05/2023] [Accepted: 06/08/2023] [Indexed: 07/09/2023]
Abstract
BACKGROUND Thymus hypoplasia due to stromal cell problems has been linked to mutations in several transcription factors, including Forkhead box N1 (FOXN1). FOXN1 supports T-cell development by regulating the formation and expansion of thymic epithelial cells (TECs). While autosomal recessive FOXN1 mutations result in a nude and severe combined immunodeficiency phenotype, the impact of single-allelic or compound heterozygous FOXN1 mutations is less well-defined. OBJECTIVE With more than 400 FOXN1 mutations reported, their impact on protein function and thymopoiesis remains unclear for most variants. We developed a systematic approach to delineate the functional impact of diverse FOXN1 variants. METHODS Selected FOXN1 variants were tested with transcriptional reporter assays and imaging studies. Thymopoiesis was assessed in mouse lines genocopying several human FOXN1 variants. Reaggregate thymus organ cultures were used to compare the thymopoietic potential of the FOXN1 variants. RESULTS FOXN1 variants were categorized into benign, loss- or gain-of-function, and/or dominant-negatives. Dominant negative activities mapped to frameshift variants impacting the transactivation domain. A nuclear localization signal was mapped within the DNA binding domain. Thymopoiesis analyses with mouse models and reaggregate thymus organ cultures revealed distinct consequences of particular Foxn1 variants on T-cell development. CONCLUSIONS The potential effect of a FOXN1 variant on T-cell output from the thymus may relate to its effects on transcriptional activity, nuclear localization, and/or dominant negative functions. A combination of functional assays and thymopoiesis comparisons enabled a categorization of diverse FOXN1 variants and their potential impact on T-cell output from the thymus.
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Affiliation(s)
- Angela Moses
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Tex
| | - Pratibha Bhalla
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Tex
| | - Austin Thompson
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Tex
| | - Laijun Lai
- Department of Allied Health Sciences, University of Connecticut, Storrs, Conn
| | - Fatma S Coskun
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Tex
| | - Christine M Seroogy
- the Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis
| | - Maria Teresa de la Morena
- the Department of Pediatrics, University of Washington and Seattle Children's Hospital, Seattle, Wash
| | - Christian A Wysocki
- Departments of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Tex; Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Tex
| | - Nicolai S C van Oers
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Tex; Departments of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Tex; Microbiology, University of Texas Southwestern Medical Center, Dallas, Tex.
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De Nisco NJ, Casey AK, Kanchwala M, Lafrance AE, Coskun FS, Kinch LN, Grishin NV, Xing C, Orth K. Manipulation of IRE1-Dependent MAPK Signaling by a Vibrio Agonist-Antagonist Effector Pair. mSystems 2021; 6:e00872-20. [PMID: 33563785 PMCID: PMC7883537 DOI: 10.1128/msystems.00872-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 01/19/2021] [Indexed: 12/05/2022] Open
Abstract
Diverse bacterial pathogens employ effector delivery systems to disrupt vital cellular processes in the host (N. M. Alto and K. Orth, Cold Spring Harbor Perspect Biol 4:a006114, 2012, https://doi.org/10.1101/cshperspect.a006114). The type III secretion system 1 of the marine pathogen Vibrio parahaemolyticus utilizes the sequential action of four effectors to induce a rapid, proinflammatory cell death uniquely characterized by a prosurvival host transcriptional response (D. L. Burdette, M. L. Yarbrough, A Orvedahl, C. J. Gilpin, and K. Orth, Proc Natl Acad Sci USA 105:12497-12502, 2008, https://doi.org/10.1073/pnas.0802773105; N. J. De Nisco, M. Kanchwala, P. Li, J. Fernandez, C. Xing, and K. Orth, Sci Signal 10:eaa14501, 2017, https://doi.org/10.1126/scisignal.aal4501). Herein, we show that this prosurvival response is caused by the action of the channel-forming effector VopQ that targets the host V-ATPase, resulting in lysosomal deacidification and inhibition of lysosome-autophagosome fusion. Recent structural studies have shown how VopQ interacts with the V-ATPase and, while in the ER, a V-ATPase assembly intermediate can interact with VopQ, causing a disruption in membrane integrity. Additionally, we observed that VopQ-mediated disruption of the V-ATPase activates the IRE1 branch of the unfolded protein response (UPR), resulting in an IRE1-dependent activation of ERK1/2 MAPK signaling. We also find that this early VopQ-dependent induction of ERK1/2 phosphorylation is terminated by the VopS-mediated inhibitory AMPylation of Rho GTPase signaling. Since VopS dampens VopQ-induced IRE1-dependent ERK1/2 activation, we propose that IRE1 activates ERK1/2 phosphorylation at or above the level of Rho GTPases. This study illustrates how temporally induced effectors can work as in tandem as agonist/antagonist to manipulate host signaling and reveals new connections between V-ATPase function, UPR, and MAPK signaling.IMPORTANCE Vibrio parahaemolyticus is a seafood-borne pathogen that encodes two type 3 secretion systems (T3SS). The first system, T3SS1, is thought to be maintained in all strains of V. parahaemolyticus to maintain survival in the environment, whereas the second system, T3SS2, is linked to clinical isolates and disease in humans. Here, we found that first system targets evolutionarily conserved signaling systems to manipulate host cells, eventually causing a rapid, orchestrated cells death within 3 h. We have found that the T3SS1 injects virulence factors that temporally manipulate host signaling. Within the first hour of infection, the effector VopQ acts first by activating host survival signals while diminishing the host cell apoptotic machinery. Less than an hour later, another effector, VopS, reverses activation and inhibition of these signaling systems, ultimately leading to death of the host cell. This work provides example of how pathogens have evolved to manipulate the interplay between T3SS effectors to regulate host signaling pathways.
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Affiliation(s)
- Nicole J De Nisco
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Amanda K Casey
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Mohammed Kanchwala
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Alexander E Lafrance
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Fatma S Coskun
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lisa N Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Nick V Grishin
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Chao Xing
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kim Orth
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Biophysics and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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3
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Coskun FS, Srivastava S, Raj P, Dozmorov I, Belkaya S, Mehra S, Golden NA, Bucsan AN, Chapagain ML, Wakeland EK, Kaushal D, Gumbo T, van Oers NSC. sncRNA-1 Is a Small Noncoding RNA Produced by Mycobacterium tuberculosis in Infected Cells That Positively Regulates Genes Coupled to Oleic Acid Biosynthesis. Front Microbiol 2020; 11:1631. [PMID: 32849337 PMCID: PMC7399025 DOI: 10.3389/fmicb.2020.01631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/23/2020] [Indexed: 12/21/2022] Open
Abstract
Nearly one third of the world’s population is infected with Mycobacterium tuberculosis (Mtb). While much work has focused on the role of different Mtb encoded proteins in pathogenesis, recent studies have revealed that Mtb also transcribes many noncoding RNAs whose functions remain poorly characterized. We performed RNA sequencing and identified a subset of Mtb H37Rv-encoded small RNAs (<30 nts in length) that were produced in infected macrophages. Designated as smaller noncoding RNAs (sncRNAs), three of these predominated the read counts. Each of the three, sncRNA-1, sncRNA-6, and sncRNA-8 had surrounding sequences with predicted stable secondary RNA stem loops. Site-directed mutagenesis of the precursor sequences suggest the existence of a hairpin loop dependent RNA processing mechanism. A functional assessment of sncRNA-1 suggested that it positively regulated two mycobacterial transcripts involved in oleic acid biosynthesis. Complementary loss- and gain- of-function approaches revealed that sncRNA-1 positively supports Mtb growth and survival in nutrient-depleted cultures as well as in infected macrophages. Overall, the findings reveal that Mtb produces sncRNAs in infected cells, with sncRNA-1 modulating mycobacterial gene expression including genes coupled to oleic acid biogenesis.
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Affiliation(s)
- Fatma S Coskun
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Shashikant Srivastava
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Baylor University Medical Center, Dallas, TX, United States
| | - Prithvi Raj
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Igor Dozmorov
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Serkan Belkaya
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Smriti Mehra
- Tulane National Primate Research Center, School of Medicine, Tulane University, Covington, LA, United States
| | - Nadia A Golden
- Tulane National Primate Research Center, School of Medicine, Tulane University, Covington, LA, United States
| | - Allison N Bucsan
- Tulane National Primate Research Center, School of Medicine, Tulane University, Covington, LA, United States
| | - Moti L Chapagain
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Baylor University Medical Center, Dallas, TX, United States
| | - Edward K Wakeland
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Deepak Kaushal
- Tulane National Primate Research Center, School of Medicine, Tulane University, Covington, LA, United States.,Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Tawanda Gumbo
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Baylor University Medical Center, Dallas, TX, United States
| | - Nicolai S C van Oers
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
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