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Tellez Freitas CM, Burrell HR, Valdoz JC, Hamblin GJ, Raymond CM, Cox TD, Johnson DK, Andersen JL, Weber KS, Bridgewater LC. The nuclear variant of bone morphogenetic protein 2 (nBMP2) is expressed in macrophages and alters calcium response. Sci Rep 2019; 9:934. [PMID: 30700748 PMCID: PMC6353957 DOI: 10.1038/s41598-018-37329-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/26/2018] [Indexed: 12/26/2022] Open
Abstract
We previously identified a nuclear variant of bone morphogenetic protein 2 (BMP2), named nBMP2, that is translated from an alternative start codon. Decreased nuclear localization of nBMP2 in the nBmp2NLStm mouse model leads to muscular, neurological, and immune phenotypes-all of which are consistent with aberrant intracellular calcium (Ca2+) response. Ca2+ response in these mice, however, has yet to be measured directly. Because a prior study suggested impairment of macrophage function in nBmp2NLStm mutant mice, bone marrow derived (BMD) macrophages and splenic macrophages were isolated from wild type and nBmp2NLStm mutant mice. Immunocytochemistry revealed that nuclei of both BMD and splenic macrophages from wild type mice contain nBMP2, while the protein is decreased in nuclei of nBmp2NLStm mutant macrophages. Live-cell Ca2+ imaging and engulfment assays revealed that Ca2+ response and phagocytosis in response to bacterial supernatant are similar in BMD macrophages isolated from naïve (uninfected) nBmp2NLStm mutant mice and wild type mice, but are deficient in splenic macrophages isolated from mutant mice after secondary systemic infection with Staphylococcus aureus, suggesting progressive impairment as macrophages respond to infection. This direct evidence of impaired Ca2+ handling in nBMP2 mutant macrophages supports the hypothesis that nBMP2 plays a role in Ca2+ response.
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Affiliation(s)
- Claudia M Tellez Freitas
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Haley R Burrell
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Jonard C Valdoz
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, United States of America
| | - Garrett J Hamblin
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Carlee M Raymond
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Tyler D Cox
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Deborah K Johnson
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Joshua L Andersen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, United States of America
| | - K Scott Weber
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America
| | - Laura C Bridgewater
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, United States of America.
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Fujihara R, Chiba Y, Nakagawa T, Murakami R, Matsumoto K, Kawauchi M, Fujii T, Shimono R, Yamamoto T, Ueno M. Histomorphometry of ectopic mineralization using undecalcified frozen bone sections. Microsc Res Tech 2018; 81:1318-1324. [PMID: 30295362 DOI: 10.1002/jemt.23140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/14/2018] [Accepted: 09/02/2018] [Indexed: 11/12/2022]
Abstract
To investigate the correlation between mineral formation and enhanced expressions of some proteins using undecalcified frozen bone sections. Histological studies have revealed that some proteins, such as BMP2, BMPR1A, and Connexin 43, are expressed in and around sites of ectopic ossification. However, the relationship between the expressed proteins considered to be associated with the ossification and mineral formation in vivo is not clear. Ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1)-mutant spinal hyperostotic TWY mice and ICR mice as controls were euthanized after calcein labeling, and undecalcified frozen sections were obtained from the middle thoracic spine. Intervertebral disc areas were examined histologically and by measuring calcein-labeled areas and areas showing immunoreactivity for BMP2, BMPR1A, and Connexin 43. Calcein-labeled areas, indicating mineralization in the ectopic mineralization sites, were significantly larger in the mutant mice than in controls. The expression of Connexin 43 was elevated in the annulus fibrosus. Increases in the calcein-labeled areas was not correlated with increases in the areas showing immunoreactivity for Connexin 43 in the annulus fibrosus. There was no statistical correlation between enhanced immunohistochemical expression and elevated calcein-labeled areas. By applying the morphometrical analysis method using undecalcified frozen sections to ENPP1-mutant mice, quantitative evaluation of the mineralization and proteins expressed in the surrounding area in the same animal became possible.
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Affiliation(s)
- Ryuji Fujihara
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan.,Department of Orthopaedic Surgery, Kagawa University, Kagawa, Japan
| | - Yoichi Chiba
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan
| | - Toshitaka Nakagawa
- Division of Research Instrument and Equipment, Life Science Research Center, Kagawa University, Kagawa, Japan
| | - Ryuta Murakami
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan
| | - Koichi Matsumoto
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan
| | - Machi Kawauchi
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan
| | - Takayuki Fujii
- Department of Pediatric Surgery, Kagawa University, Kagawa, Japan
| | - Ryuichi Shimono
- Department of Pediatric Surgery, Kagawa University, Kagawa, Japan
| | - Tetsuji Yamamoto
- Department of Orthopaedic Surgery, Kagawa University, Kagawa, Japan
| | - Masaki Ueno
- Department of Pathology and Host Defense, Kagawa University, Kagawa, Japan
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Cordner RD, Friend LN, Mayo JL, Badgley C, Wallmann A, Stallings CN, Young PL, Miles DR, Edwards JG, Bridgewater LC. The BMP2 nuclear variant, nBMP2, is expressed in mouse hippocampus and impacts memory. Sci Rep 2017; 7:46464. [PMID: 28418030 PMCID: PMC5394474 DOI: 10.1038/srep46464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 03/20/2017] [Indexed: 12/23/2022] Open
Abstract
The novel nuclear protein nBMP2 is synthesized from the BMP2 gene by translational initiation at an alternative start codon. We generated a targeted mutant mouse, nBmp2NLStm, in which the nuclear localization signal (NLS) was inactivated to prevent nuclear translocation of nBMP2 while still allowing the normal synthesis and secretion of the BMP2 growth factor. These mice exhibit abnormal muscle function due to defective Ca2+ transport in skeletal muscle. We hypothesized that neurological function, which also depends on intracellular Ca2+ transport, could be affected by the loss of nBMP2. Age-matched nBmp2NLStm and wild type mice were analyzed by immunohistochemistry, behavioral tests, and electrophysiology to assess nBMP2 expression and neurological function. Immunohistochemical staining of the hippocampus detected nBMP2 in the nuclei of CA1 neurons in wild type but not mutant mice, consistent with nBMP2 playing a role in the hippocampus. Mutant mice showed deficits in the novel object recognition task, suggesting hippocampal dysfunction. Electrophysiology experiments showed that long-term potentiation (LTP) in the hippocampus, which is dependent on intracellular Ca2+ transport and is thought to be the cellular equivalent of learning and memory, was impaired. Together, these results suggest that nBMP2 in the hippocampus impacts memory formation.
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Affiliation(s)
- Ryan D. Cordner
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Lindsey N. Friend
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Jaime L. Mayo
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Corinne Badgley
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Andrew Wallmann
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Conrad N. Stallings
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Peter L. Young
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Darla R. Miles
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
| | - Jeffrey G. Edwards
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Laura C. Bridgewater
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah, USA
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Targeted Mutation of Nuclear Bone Morphogenetic Protein 2 Impairs Secondary Immune Response in a Mouse Model. BIOMED RESEARCH INTERNATIONAL 2015; 2015:975789. [PMID: 26491697 PMCID: PMC4603606 DOI: 10.1155/2015/975789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/24/2015] [Indexed: 11/29/2022]
Abstract
We recently identified a nuclear variant of the BMP2 growth factor, called nBMP2. In an effort to understand the function of this variant protein, we generated a mouse line in which BMP2 is expressed and functions normally, but nBMP2 is excluded from the nucleus. This novel mutation allows the study of nBMP2 without compromising BMP2 function. To determine whether nBMP2 plays a role in immune function, we performed a series of experiments in which we compared mouse survival, organ weights, immune cells numbers, and bacterial load in wild type and nBmp2NLStm mice following primary and secondary challenges with Staphylococcus aureus. Following primary challenge with S. aureus, wild type and nBmp2NLStm mice showed no differences in survival or bacterial load and generated similar numbers and types of leukocytes, although mutant spleens were smaller than wild type. Secondary bacterial challenge with S. aureus, however, produced differences in survival, with increased mortality seen in nBmp2NLStm mice. This increased mortality corresponded to higher levels of bacteremia in nBmp2NLStm mice and to a reduced enlargement of mutant spleens in response to the secondary infection. Together, these results suggest that the recently described nuclear variant of BMP2 is necessary for efficient secondary immune responses.
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