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Chang CM, Chang WC, Hsieh SL. Characterization of the genetic variation and evolutionary divergence of the CLEC18 family. J Biomed Sci 2024; 31:53. [PMID: 38764023 PMCID: PMC11103991 DOI: 10.1186/s12929-024-01034-5] [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: 02/17/2024] [Accepted: 04/25/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND The C-type lectin family 18 (CLEC18) with lipid and glycan binding capabilities is important to metabolic regulation and innate immune responses against viral infection. However, human CLEC18 comprises three paralogous genes with highly similar sequences, making it challenging to distinguish genetic variations, expression patterns, and biological functions of individual CLEC18 paralogs. Additionally, the evolutionary relationship between human CLEC18 and its counterparts in other species remains unclear. METHODS To identify the sequence variation and evolutionary divergence of human CLEC18 paralogs, we conducted a comprehensive analysis using various resources, including human and non-human primate reference genome assemblies, human pangenome assemblies, and long-read-based whole-genome and -transcriptome sequencing datasets. RESULTS We uncovered paralogous sequence variants (PSVs) and polymorphic variants (PVs) of human CLEC18 proteins, and identified distinct signatures specific to each CLEC18 paralog. Furthermore, we unveiled a novel segmental duplication for human CLEC18A gene. By comparing CLEC18 across human and non-human primates, our research showed that the CLEC18 paralogy probably occurred in the common ancestor of human and closely related non-human primates, and the lipid-binding CAP/SCP/TAPS domain of CLEC18 is more diverse than its glycan-binding CTLD. Moreover, we found that certain amino acids alterations at variant positions are exclusive to human CLEC18 paralogs. CONCLUSIONS Our findings offer a comprehensive profiling of the intricate variations and evolutionary characteristics of human CLEC18.
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Affiliation(s)
- Che-Mai Chang
- Genomics Research Center, Academia Sinica, No. 128, Sec. 2, Academia Rd., Nangang Dist., Taipei City, 115, Taiwan
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, No.250, Wuxing St., Xinyi Dist, Taipei City, 110, Taiwan
| | - Wei-Chiao Chang
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, No.250, Wuxing St., Xinyi Dist, Taipei City, 110, Taiwan.
- Master Program in Clinical Genomics and Proteomics, School of Pharmacy, Taipei Medical University, Taipei City, 110, Taiwan.
- Department of Pharmacy, Wan Fang Hospital, Taipei Medical University, Taipei City, 116, Taiwan.
- Integrative Research Center for Critical Care, Wan Fang Hospital, Taipei Medical University, Taipei City, 116, Taiwan.
- Department of Pharmacology, National Defense Medical Center, Taipei City, 114, Taiwan.
| | - Shie-Liang Hsieh
- Genomics Research Center, Academia Sinica, No. 128, Sec. 2, Academia Rd., Nangang Dist., Taipei City, 115, Taiwan.
- Master Program in Clinical Genomics and Proteomics, School of Pharmacy, Taipei Medical University, Taipei City, 110, Taiwan.
- Immunology Research Center, National Health Research Institutes, No. 35, Keyan Rd., Zhunan Township, Miaoli County, 350, Taiwan.
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei City, 112, Taiwan.
- Department of Medical Research, Taipei Veterans General Hospital, Taipei City, 112, Taiwan.
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Huang J, Meng Q, Liu R, Li H, Li Y, Yang Z, Wang Y, Wanyan C, Yang X, Wei J. The development of radioresistant oral squamous carcinoma cell lines and identification of radiotherapy-related biomarkers. Clin Transl Oncol 2023; 25:3006-3020. [PMID: 37029240 DOI: 10.1007/s12094-023-03169-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/21/2023] [Indexed: 04/09/2023]
Abstract
BACKGROUND In the treatment of oral squamous cell carcinoma (OSCC), radiation resistance remains an important obstacle to patient outcomes. Progress in understanding the molecular mechanisms of radioresistance has been limited by research models that do not fully recapitulate the biological features of solid tumors. In this study, we aimed to develop novel in vitro models to investigate the underlying basis of radioresistance in OSCC and to identify novel biomarkers. METHODS Parental OSCC cells (SCC9 and CAL27) were repeatedly exposed to ionizing radiation to develop isogenic radioresistant cell lines. We characterized the phenotypic differences between the parental and radioresistant cell lines. RNA sequencing was used to identify differentially expressed genes (DEGs), and bioinformatics analysis identified candidate molecules that may be related to OSCC radiotherapy. RESULTS Two isogenic radioresistant cell lines for OSCC were successfully established. The radioresistant cells displayed a radioresistant phenotype when compared to the parental cells. Two hundred and sixty DEGs were co-expressed in SCC9-RR and CAL27-RR, and thirty-eight DEGs were upregulated or downregulated in both cell lines. The associations between the overall survival (OS) of OSCC patients and the identified genes were analyzed using data from the Cancer Genome Atlas (TCGA) database. A total of six candidate genes (KCNJ2, CLEC18C, P3H3, PIK3R3, SERPINE1, and TMC8) were closely associated with prognosis. CONCLUSION This study demonstrated the utility of constructing isogenic cell models to investigate the molecular changes associated with radioresistance. Six genes were identified based on the data from the radioresistant cells that may be potential targets in the treatment of OSCC.
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Affiliation(s)
- Junhong Huang
- College of Life Science, Northwest University, Xi'an, 710069, China
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Qingzhe Meng
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
- School of Stomatology, Heilongjiang Key Lab of Oral Biomedicine Materials and Clinical Application & Experimental Center for Stomatology Engineering, Jiamusi University, Jiamusi, 154000, China
| | - Rong Liu
- College of Life Science, Northwest University, Xi'an, 710069, China
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Huan Li
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Yahui Li
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Zihui Yang
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Yan Wang
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Chaojie Wanyan
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - Xinjie Yang
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China.
| | - Jianhua Wei
- State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases, and Shaanxi Clinical Research Center for Oral Diseases, Department of Oral and Maxillofacial Surgery, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China.
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Liao TL, Chen YM, Tang KT, Yang YY, Chen DY, Chan TH, Tsai HJ, Hsieh SL. CLEC18A Impairs Phagocytosis by Reducing FcγRIIA Expression and Arresting Autophagosome-Lysosome Fusion. Microbiol Spectr 2023; 11:e0290322. [PMID: 37154715 PMCID: PMC10269929 DOI: 10.1128/spectrum.02903-22] [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: 07/27/2022] [Accepted: 03/28/2023] [Indexed: 05/10/2023] Open
Abstract
Mixed cryoglobulinemia (MC) is a hepatitis C virus (HCV)-related extrahepatic manifestation that is characterized by the abnormal presence of immune complexes (ICs). This may be due to the reduced uptake and clearance of ICs. The C-type lectin member 18A (CLEC18A) is a secretory protein that is expressed abundantly in hepatocytes. We previously observed that CLEC18A increased significantly in the phagocytes and sera of patients with HCV, particularly those with MC. Herein, we explored the biological functions of CLEC18A in the MC syndrome development of patients with HCV by using an in vitro cell-based assay with quantitative reverse transcription-PCR, immunoblotting, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. HCV infection or Toll-like receptor 3/7/8 activation could induce CLEC18A expression in Huh7.5 cells. Upregulated CLEC18A interacts with Rab5 and Rab7 and enhances type I/III interferon production to inhibit HCV replication in hepatocytes. However, overexpressed CLEC18A suppressed phagocytic activity in phagocytes. Significantly decreased levels of the Fc gamma receptor (FcγR) IIA were found in the neutrophils of HCV patients, particularly in those with MC (P < 0.005). We demonstrated that CLEC18A could inhibit FcγRIIA expression in a dose-dependent manner through the production of NOX-2-dependent reactive oxygen species to impair the uptake of ICs. Additionally, CLEC18A suppresses the Rab7 expression that is induced by starvation. Overexpressed CLEC18A does not affect autophagosome formation but does reduce the recruitment of Rab7 to autophagosomes, thereby retarding the maturation of autophagosomes and affecting autophagosome-lysosome fusion. We offer a novel molecular machinery with which to understand the association of HCV infection with autoimmunity and propose that CLEC18A may act as a candidate biomarker for HCV-associated MC. IMPORTANCE During infection, the host immune system produces cellular factors to protect against pathogen invasion. However, when the immune response overreacts and there is dysregulated cytokine homeostasis, autoimmunity occurs following an infection. We identified a cellular factor that is involved in HCV-related extrahepatic manifestation, namely, CLEC18A, which is expressed abundantly in hepatocytes and phagocytes. It inhibits HCV replication in hepatocytes by interacting with Rab5/7 and enhancing type I/III IFN expression. However, overexpressed CLEC18A inhibited FcγRIIA expression in phagocytes to impair phagocytosis. Furthermore, the interaction between CLEC18A and Rab5/7 may reduce the recruitment of Rab7 to autophagosomes and thereby retard autophagosome maturation and cause immune complex accumulation. A decreasing trend in CLEC18A levels that was accompanied by reduced HCV RNA titers and diminished cryoglobulin was observed in the sera of HCV-MC patients after direct-acting antiviral therapy. CLEC18A may be used for the evaluation of anti-HCV therapeutic drug effects and could be a potential predisposing factor for the development of MC syndrome.
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Affiliation(s)
- Tsai-Ling Liao
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
- Ph.D. Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ming Chen
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
- Ph.D. Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Kuo-Tung Tang
- Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Ying-Ying Yang
- Division of Gastroenterology and Hepatology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Der-Yuan Chen
- Rheumatology and Immunology Center, China Medical University Hospital, Taichung, Taiwan
- Translational Medicine Laboratory, Rheumatology and Immunology Center, China Medical University Hospital, Taichung, Taiwan
- College of Medicine, China Medical University, Taichung, Taiwan
- Institute of Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Tsung-Hsien Chan
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Hui-Ju Tsai
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Shie-Liang Hsieh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
- Immunology Research Center, National Health Research Institutes, Zhunan, Miaoli, Taiwan
- Institute of Clinical Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
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Hsu YW, Wong HSC, Huang WC, Yeh YH, Hsiao CD, Chang WC, Hsieh SL. Human rs75776403 polymorphism links differential phenotypic and clinical outcomes to a CLEC18A p.T151M-driven multiomics. J Biomed Sci 2022; 29:43. [PMID: 35717171 PMCID: PMC9206359 DOI: 10.1186/s12929-022-00822-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 06/03/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human traits, diseases susceptibility, and clinical outcomes vary hugely among individuals. Despite a fundamental understanding of genetic (or environmental) contributions, the detailed mechanisms of how genetic variation impacts molecular or cellular behaviours of a gene, and subsequently leads to such variability remain poorly understood. METHODS Here, in addition to phenome-wide correlations, we leveraged multiomics to exploit mechanistic links, from genetic polymorphism to protein structural or functional changes and a cross-omics perturbation landscape of a germline variant. RESULTS We identified a missense cis-acting expression quantitative trait locus in CLEC18A (rs75776403) in which the altered residue (T151→M151) disrupts the lipid-binding ability of the protein domain. The altered allele carriage led to a metabolic and proliferative shift, as well as immune deactivation, therefore determines human anthropometrics (body height), kidney, and hematological traits. CONCLUSIONS Collectively, we uncovered genetic pleiotropy in human complex traits and diseases via CLEC18A rs75776403-regulated pathways.
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Affiliation(s)
- Yu-Wen Hsu
- The Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University and Academia Sinica, Taipei, Taiwan
| | - Henry Sung-Ching Wong
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Wan-Chen Huang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.,Institute of Medical Device and Imaging, National Taiwan University, Taipei, Taiwan
| | - Yi-Hung Yeh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | | | - Wei-Chiao Chang
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan. .,Department of Pharmacy, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan. .,Integrative Research Center in Critical Care, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
| | - Shie-Liang Hsieh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan. .,Institute of Clinical Medicine, National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan. .,Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan. .,Graduate of Institute of Cancer Biology and Drug Discovery, Taipei Medical University, Taipei, Taiwan.
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Hepatitis C Virus-Induced Exosomal MicroRNAs and Toll-Like Receptor 7 Polymorphism Regulate B-Cell Activating Factor. mBio 2021; 12:e0276421. [PMID: 34724826 PMCID: PMC8561394 DOI: 10.1128/mbio.02764-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
There are large gaps in understanding the molecular machinery accounting for the association of hepatitis C virus (HCV) infection with autoimmunity. Mixed cryoglobulinemia (MC) is the most common HCV-associated extrahepatic manifestation, which is characterized by B-cell lymphoproliferation and autoantibody production. B-cell activating factor (BAFF) is a member of the tumor necrosis factor family and plays an important role in B-cell proliferation. We explored the roles of hepatocyte-derived exosomal microRNAs (exo-miRNAs) and BAFF in the extrahepatic diseases of HCV infection. The exo-miRNA profiles were explored using a next-generation sequencing approach, followed by quantitative reverse transcription-PCR validation. The Toll-like receptor 7 (TLR7) polymorphism were analyzed using quantitative PCR. The biological function of exo-miRNAs and TLR7 polymorphism in BAFF expression was evaluated by using immunoblotting and enzyme-linked immunosorbent assay. Significantly increased levels of BAFF, exosomes, and TLR7 were found in HCV patients, particularly in those with MC (P < 0.005). HCV-infected hepatocyte-derived miR-122/let-7b/miR-206 upregulated BAFF expression in human macrophages through exosome transmission and TLR7 activation. Analysis of a TLR7 single-nucleotide polymorphism (rs3853839) revealed that G-allele carriers had increased TLR7 transcripts, resulting in more BAFF expression induced by hepatocyte-derived exo-miR-122, compared to those in C-allele carriers (P < 0.005). We identified HCV-infected hepatocyte-derived GU-enriched miRNAs (e.g., miR-122/let-7b/miR-206) as a TLR7 ligand that could induce BAFF production in macrophages through exosome transmission. The polymorphism in TLR7 is associated with the BAFF levels induced by exo-miR-122. It may be a potential predisposing factor of MC syndrome development.
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Huang YL, Huang MT, Sung PS, Chou TY, Yang RB, Yang AS, Yu CM, Hsu YW, Chang WC, Hsieh SL. Endosomal TLR3 co-receptor CLEC18A enhances host immune response to viral infection. Commun Biol 2021; 4:229. [PMID: 33603190 PMCID: PMC7893028 DOI: 10.1038/s42003-021-01745-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 01/07/2021] [Indexed: 12/15/2022] Open
Abstract
Human C-type lectin member 18A (CLEC18A) is ubiquitously expressed in human, and highest expression levels are found in human myeloid cells and liver. In contrast, mouse CLEC18A (mCLEC18A) is only expressed in brain, kidney and heart. However, the biological functions of CLEC18A are still unclear. We have shown that a single amino acid change (S339 →R339) in CTLD domain has profound effect in their binding to polysaccharides and house dust mite allergens. In this study, we further demonstrate that CLEC18A and its mutant CLEC18A(S339R) associate with TLR3 in endosome and bind poly (I:C) specifically. Compared to TLR3 alone, binding affinity to poly (I:C) is further increased in TLR3-CLEC18A and TLR3-CLEC18A(S339R) complexes. Moreover, CLEC18A and CLEC18A(S339R) enhance the production of type I and type III interferons (IFNs), but not proinflammatory cytokines, in response to poly (I:C) or H5N1 influenza A virus (IAV) infection. Compared to wild type (WT) mice, ROSA-CLEC18A and ROSA-CLEC18A(S339R) mice generate higher amounts of interferons and are more resistant to H5N1 IAV infection. Thus, CLEC18A is a TLR3 co-receptor, and may contribute to the differential immune responses to poly (I:C) and IAV infection between human and mouse.
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Affiliation(s)
- Ya-Lang Huang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | | | - Pei-Shan Sung
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Teh-Ying Chou
- Department of Pathology, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Ruey-Bing Yang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - An-Suei Yang
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Chung-Ming Yu
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Yu-Wen Hsu
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Wei-Chiao Chang
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Shie-Liang Hsieh
- Genomics Research Center, Academia Sinica, Taipei, Taiwan.
- Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
- Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan.
- Institute for Cancer Biology and Drug Discovery, Taipei Medical University, Taipei, Taiwan.
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Gaikwad AS, Hu J, Chapple DG, O'Bryan MK. The functions of CAP superfamily proteins in mammalian fertility and disease. Hum Reprod Update 2020; 26:689-723. [PMID: 32378701 DOI: 10.1093/humupd/dmaa016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/11/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Members of the cysteine-rich secretory proteins (CRISPS), antigen 5 (Ag5) and pathogenesis-related 1 (Pr-1) (CAP) superfamily of proteins are found across the bacterial, fungal, plant and animal kingdoms. Although many CAP superfamily proteins remain poorly characterized, over the past decade evidence has accumulated, which provides insights into the functional roles of these proteins in various processes, including fertilization, immune defence and subversion, pathogen virulence, venom toxicology and cancer biology. OBJECTIVE AND RATIONALE The aim of this article is to summarize the current state of knowledge on CAP superfamily proteins in mammalian fertility, organismal homeostasis and disease pathogenesis. SEARCH METHODS The scientific literature search was undertaken via PubMed database on all articles published prior to November 2019. Search terms were based on following keywords: 'CAP superfamily', 'CRISP', 'Cysteine-rich secretory proteins', 'Antigen 5', 'Pathogenesis-related 1', 'male fertility', 'CAP and CTL domain containing', 'CRISPLD1', 'CRISPLD2', 'bacterial SCP', 'ion channel regulator', 'CatSper', 'PI15', 'PI16', 'CLEC', 'PRY proteins', 'ASP proteins', 'spermatogenesis', 'epididymal maturation', 'capacitation' and 'snake CRISP'. In addition to that, reference lists of primary and review article were reviewed for additional relevant publications. OUTCOMES In this review, we discuss the breadth of knowledge on CAP superfamily proteins with regards to their protein structure, biological functions and emerging significance in reproduction, health and disease. We discuss the evolution of CAP superfamily proteins from their otherwise unembellished prokaryotic predecessors into the multi-domain and neofunctionalized members found in eukaryotic organisms today. At least in part because of the rapid evolution of these proteins, many inconsistencies in nomenclature exist within the literature. As such, and in part through the use of a maximum likelihood phylogenetic analysis of the vertebrate CRISP subfamily, we have attempted to clarify this confusion, thus allowing for a comparison of orthologous protein function between species. This framework also allows the prediction of functional relevance between species based on sequence and structural conservation. WIDER IMPLICATIONS This review generates a picture of critical roles for CAP proteins in ion channel regulation, sterol and lipid binding and protease inhibition, and as ligands involved in the induction of multiple cellular processes.
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Affiliation(s)
- Avinash S Gaikwad
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Jinghua Hu
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - David G Chapple
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
| | - Moira K O'Bryan
- School of Biological Sciences, Monash University, Clayton, Victoria, 3800, Australia
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