1
|
Cao S, Wang D, Liu L, Yao J, Wang L, Liao Y, Zhang J, Zhao J, Huang Y, Hao Z. Association of ACTN4 Gene Mutation with Primary Nephrotic Syndrome in Children in Guangxi Autonomous Region, China. Genet Test Mol Biomarkers 2024; 28:281-288. [PMID: 38949978 DOI: 10.1089/gtmb.2023.0567] [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] [Indexed: 07/03/2024] Open
Abstract
Objective: To investigate the association between ACTN4 gene mutation and primary nephrotic syndrome (PNS) in children in Guangxi Autonomous Region, China. Methods: The high-throughput sequencing technology was used to sequence ACTN4 gene in 155 children with PNS in Guangxi Autonomous Region in China, with 98 healthy children serving as controls. Twenty-three exon-specific capture probes targeting ACTN4 were designed and used to hybridize with the genomic DNA library. The targeted genomic region DNA fragments were enriched and sequenced. The protein levels of ACTN4 in both case and control groups were quantified using ELISA method. Results: Bioinformatics analysis revealed five unique ACTN4 mutations exclusively in patients with PNS, including c.1516G>A (p.G506S) on one exon in 2 patients, c.1442 + 10G>A at the splice site in 1 patient, c.1649A>G (p.D550G) on exon in 1 patient, c.2191-4G>A at the cleavage site in 2 patients, and c.2315C>T (p.A772V) on one exon in 1 patient. The c.1649A>G (p.D550G) and c.2315C>T (p.A772V) were identified from the same patient. Notably, c.1649A>G (p.D550G) represents a novel mutation in ACTN4. In addition, three other ACTN4 polymorphisms occurred in both case and control groups, including c.162 + 6C>T (1 patient in case group and 2 patients in control group), c.572 + 11G>A (1 patient in case group and 2 patients in control group), and c.2191-5C>T (4 patients in the case group and 3 patients in control group). The serum ACTN4 concentration in the case group was markedly higher, averaging 544.7 ng/mL (range: 264.6-952.6 ng/mL), compared with 241.20 ng/mL (range: 110.75-542.35 ng/mL) in the control group. Conclusion: Five ACTN4 polymorphisms were identified among children with PNS in Guangxi Autonomous Region, China, including the novel mutation c.1649A>G. The lower serum levels of α-actinin-4 in the case group suggest that this protein might play a protective role in PNS.
Collapse
Affiliation(s)
- Shan Cao
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Dan Wang
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Lixiao Liu
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Junyan Yao
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Lingli Wang
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Yang Liao
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Jinfeng Zhang
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Jie Zhao
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Ying Huang
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| | - Zhiyan Hao
- Department of Pediatrics, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai, China
| |
Collapse
|
2
|
Feng D, Steinke JM, Krishnan R, Birrane G, Pollak MR. Functional Validation of an Alpha-Actinin-4 Mutation as a Potential Cause of an Aggressive Presentation of Adolescent Focal Segmental Glomerulosclerosis: Implications for Genetic Testing. PLoS One 2016; 11:e0167467. [PMID: 27977723 PMCID: PMC5158186 DOI: 10.1371/journal.pone.0167467] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 10/30/2016] [Indexed: 11/18/2022] Open
Abstract
Genetic testing in the clinic and research lab is becoming more routinely used to identify rare genetic variants. However, attributing these rare variants as the cause of disease in an individual patient remains challenging. Here, we report a patient who presented with nephrotic syndrome and focal segmental glomerulosclerosis (FSGS) with collapsing features at age 14. Despite treatment, her kidney disease progressed to end-stage within a year of diagnosis. Through genetic testing, an Y265H variant with unknown clinical significance in alpha-actinin-4 gene (ACTN4) was identified. This variant has not been seen previously in FSGS patients nor is it present in genetic databases. Her clinical presentation is different from previous descriptions of ACTN4 mediated FSGS, which is characterized by sub-nephrotic proteinuria and slow progression to end stage kidney disease. We performed in vitro and cellular assays to characterize this novel ACTN4 variant before attributing causation. We found that ACTN4 with either Y265H or K255E (a known disease-causing mutation) increased the actin bundling activity of ACTN4 in vitro, was associated with the formation of intracellular aggregates, and increased podocyte contractile force. Despite the absence of a familial pattern of inheritance, these similar biological changes caused by the Y265H and K255E amino acid substitutions suggest that this new variant is potentially the cause of FSGS in this patient. Our studies highlight that functional validation in complement with genetic testing may be required to confirm the etiology of rare disease, especially in the setting of unusual clinical presentations.
Collapse
Affiliation(s)
- Di Feng
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Julia M. Steinke
- Division of Pediatric Nephrology and Transplantation, Helen DeVos Children's Hospital at Spectrum Health, Grand Rapids, Michigan, United States of America
| | - Ramaswamy Krishnan
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gabriel Birrane
- Division of Experimental Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Martin R. Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
3
|
Hossain MM, Zhao G, Woo MS, Wang JHC, Jin JP. Deletion of Calponin 2 in Mouse Fibroblasts Increases Myosin II-Dependent Cell Traction Force. Biochemistry 2016; 55:6046-6055. [PMID: 27733037 DOI: 10.1021/acs.biochem.6b00856] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cell traction force (CTF) plays a critical role in controlling cell shape, permitting cell motility, and maintaining cellular homeostasis in many biological processes such as angiogenesis, development, wound healing, and cancer metastasis. Calponin is an actin filament-associated cytoskeletal protein in smooth muscles and multiple types of non-muscle cells. An established biochemical function of calponin is the inhibition of myosin ATPase in smooth muscle cells. Vertebrates have three calponin isoforms. Among them, calponin 2 is expressed in epithelial cells, endothelial cells, macrophages, myoblasts, and fibroblasts and plays a role in regulating cytoskeleton activities such as cell adhesion, migration, and cytokinesis. Knockout (KO) of the gene encoding calponin 2 (Cnn2) in mice increased cell motility, suggesting a function of calponin 2 in modulating CTF. In this study, we examined fibroblasts isolated from Cnn2 KO and wild-type (WT) mice using CTF microscopy. Primary mouse fibroblasts were cultured on polyacrylamide gel substrates embedded with fluorescent beads to measure root-mean-square traction, total strain energy, and net contractile movement. The results showed that calponin 2-null fibroblasts exhibit traction force greater than that of WT cells. Adherent calponin 2-null fibroblasts de-adhered faster than the WT control during mild trypsin treatment, consistent with an increased CTF. Blebbistatin, an inhibitor of myosin II ATPase, is more effective upon an alteration in cell morphology when calponin 2 is present in WT fibroblasts than that on Cnn2 KO cells, indicating their additive effects in inhibiting myosin motor activity. The novel finding that calponin 2 regulates myosin-dependent CTF in non-muscle cells demonstrates a mechanism for controlling cell motility-based functions.
Collapse
Affiliation(s)
- M Moazzem Hossain
- Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| | - Guangyi Zhao
- Departments of Orthopedic Surgery and Bioengineering, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Moon-Sook Woo
- Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| | - James H-C Wang
- Departments of Orthopedic Surgery and Bioengineering, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Jian-Ping Jin
- Department of Physiology, Wayne State University School of Medicine , Detroit, Michigan 48201, United States
| |
Collapse
|