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Shum W, Zhang BL, Cao AS, Zhou X, Shi SM, Zhang ZY, Gu LY, Shi S. Calcium Homeostasis in the Epididymal Microenvironment: Is Extracellular Calcium a Cofactor for Matrix Gla Protein-Dependent Scavenging Regulated by Vitamins. Front Cell Dev Biol 2022; 10:827940. [PMID: 35252193 PMCID: PMC8893953 DOI: 10.3389/fcell.2022.827940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/19/2022] [Indexed: 12/23/2022] Open
Abstract
In the male reproductive tract, the epididymis is an essential organ for sperm maturation, in which sperm cells acquire mobility and the ability to fertilize oocytes while being stored in a protective microenvironment. Epididymal function involves a specialized luminal microenvironment established by the epithelial cells of epididymal mucosa. Low-calcium concentration is a unique feature of this epididymal luminal microenvironment, its relevance and regulation are, however, incompletely understood. In the rat epididymis, the vitamin D-related calcium-dependent TRPV6-TMEM16A channel-coupler has been shown to be involved in fluid transport, and, in a spatially complementary manner, vitamin K2-related γ-glutamyl carboxylase (GGCX)-dependent carboxylation of matrix Gla protein (MGP) plays an essential role in promoting calcium-dependent protein aggregation. An SNP in the human GGCX gene has been associated with asthenozoospermia. In addition, bioinformatic analysis also suggests the involvement of a vitamin B6-axis in calcium-dependent MGP-mediated protein aggregation. These findings suggest that vitamins interact with calcium homeostasis in the epididymis to ensure proper sperm maturation and male fertility. This review article discusses the regulation mechanisms of calcium homeostasis in the epididymis, and the potential role of vitamin interactions on epididymal calcium homeostasis, especially the role of matrix calcium in the epididymal lumen as a cofactor for the carboxylated MGP-mediated scavenging function.
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Affiliation(s)
- Winnie Shum
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Winnie Shum,
| | - Bao Li Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- NHC Key Lab of Reproduction Regulation, Shanghai Institute for Biomedical and Pharmaceutical Technologies, Reproduction and Development Institution, Fudan University, Shanghai, China
| | - Albert Shang Cao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xin Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Su Meng Shi
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Ze Yang Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lou Yi Gu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Shuo Shi
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
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Molecular basis of the first reported clinical case of congenital combined deficiency of coagulation factors. Blood 2017; 130:948-951. [PMID: 28679738 DOI: 10.1182/blood-2017-05-782367] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Tie JK, Carneiro JDA, Jin DY, Martinhago CD, Vermeer C, Stafford DW. Characterization of vitamin K-dependent carboxylase mutations that cause bleeding and nonbleeding disorders. Blood 2016; 127:1847-55. [PMID: 26758921 PMCID: PMC4832504 DOI: 10.1182/blood-2015-10-677633] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/06/2016] [Indexed: 01/07/2023] Open
Abstract
Vitamin K-dependent coagulation factors deficiency is a bleeding disorder mainly associated with mutations in γ-glutamyl carboxylase (GGCX) that often has fatal outcomes. Some patients with nonbleeding syndromes linked to GGCX mutations, however, show no coagulation abnormalities. The correlation between GGCX genotypes and their clinical phenotypes has been previously unknown. Here we report the identification and characterization of novel GGCX mutations in a patient with both severe cerebral bleeding disorder and comorbid Keutel syndrome, a nonbleeding malady caused by functional defects of matrix γ-carboxyglutamate protein (MGP). To characterize GGCX mutants in a cellular milieu, we established a cell-based assay by stably expressing 2 reporter proteins (a chimeric coagulation factor and MGP) in HEK293 cells. The endogenous GGCX gene in these cells was knocked out by CRISPR-Cas9-mediated genome editing. Our results show that, compared with wild-type GGCX, the patient's GGCX D153G mutant significantly decreased coagulation factor carboxylation and abolished MGP carboxylation at the physiological concentration of vitamin K. Higher vitamin K concentrations can restore up to 60% of coagulation factor carboxylation but do not ameliorate MGP carboxylation. These results are consistent with the clinical results obtained from the patient treated with vitamin K, suggesting that the D153G alteration in GGCX is the causative mutation for both the bleeding and nonbleeding disorders in our patient. These findings provide the first evidence of a GGCX mutation resulting in 2 distinct clinical phenotypes; the established cell-based assay provides a powerful tool for studying the clinical consequences of naturally occurring GGCX mutations in vivo.
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Affiliation(s)
- Jian-Ke Tie
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Jorge D A Carneiro
- Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
| | - Da-Yun Jin
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | | | - Cees Vermeer
- R&D Group VitaK, Maastricht University, Maastricht, The Netherlands
| | - Darrel W Stafford
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
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Sun YM, Jin DY, Camire RM, Stafford DW. Vitamin K epoxide reductase significantly improves carboxylation in a cell line overexpressing factor X. Blood 2005; 106:3811-5. [PMID: 16081695 DOI: 10.1182/blood-2005-06-2495] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Previously we reported that we could increase the fraction of carboxylated factor X by reducing the affinity of the propeptide for its binding site on human gamma glutamyl carboxylase. We attributed this to an increased turnover rate. However, even with the reduced affinity propeptide, when sufficient overproduction of factor X is achieved, there is still a significant fraction of uncarboxylated recombinant factor X. We report here that the factor X of such a cell line was only 52% carboxylated but that the fraction of carboxylated factor X could be increased to 92% by coexpressing the recently identified gene for vitamin K epoxide reductase. Because vitamin K is in excess in both the untransfected and vitamin K epoxide reductase (VKOR)–transfected cells, the simplest explanation for this result is that VKOR catalyzes both the reduction of vitamin K epoxide to vitamin K and the conversion of vitamin K to vitamin K hydroquinone. In addition to its mechanistic relevance, this observation has practical implications for overproducing recombinant vitamin K–dependent proteins for therapeutic use.
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Affiliation(s)
- Yan-Mei Sun
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA
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