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Li Q, Chen J, Liu J, Lin T, Liu X, Zhang S, Yue X, Zhang X, Zeng X, Ren M, Guan W, Zhang S. Leucine and arginine enhance milk fat and milk protein synthesis via the CaSR/G i/mTORC1 and CaSR/G q/mTORC1 pathways. Eur J Nutr 2023; 62:2873-2890. [PMID: 37392244 DOI: 10.1007/s00394-023-03197-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/23/2023] [Indexed: 07/03/2023]
Abstract
BACKGROUND AND AIMS Amino acids (AAs) not only constitute milk protein but also stimulate milk synthesis through the activation of mTORC1 signaling, but which amino acids that have the greatest impact on milk fat and protein synthesis is still very limited. In this study, we aimed to identify the most critical AAs involved in the regulation of milk synthesis and clarify how these AAs regulate milk synthesis through the G-protein-coupled receptors (GPCRs) signaling pathway. METHODS In this study, a mouse mammary epithelial cell line (HC11) and porcine mammary epithelial cells (PMECs) were selected as study subjects. After treatment with different AAs, the amount of milk protein and milk fat synthesis were detected. Activation of mTORC1 and GPCRs signaling induced by AAs was also investigated. RESULTS In this study, we demonstrate that essential amino acids (EAAs) are crucial to promote lactation by increasing the expression of genes and proteins related to milk synthesis, such as ACACA, FABP4, DGAT1, SREBP1, α-casein, β-casein, and WAP in HC11 cells and PMECs. In addition to activating mTORC1, EAAs uniquely regulate the expression of calcium-sensing receptor (CaSR) among all amino-acid-responsive GPCRs, which indicates a potential link between CaSR and the mTORC1 pathway in mammary gland epithelial cells. Compared with other EAAs, leucine and arginine had the greatest capacity to trigger GPCRs (p-ERK) and mTORC1 (p-S6K1) signaling in HC11 cells. In addition, CaSR and its downstream G proteins Gi, Gq, and Gβγ are involved in the regulation of leucine- and arginine-induced milk synthesis and mTORC1 activation. Taken together, our data suggest that leucine and arginine can efficiently trigger milk synthesis through the CaSR/Gi/mTORC1 and CaSR/Gq/mTORC1 pathways. CONCLUSION We found that the G-protein-coupled receptor CaSR is an important amino acid sensor in mammary epithelial cells. Leucine and arginine promote milk synthesis partially through the CaSR/Gi/mTORC1 and CaSR/Gq/mTORC1 signaling systems in mammary gland epithelial cells. Although this mechanism needs further verification, it is foreseeable that this mechanism may provide new insights into the regulation of milk synthesis.
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Affiliation(s)
- Qihui Li
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Jiaming Chen
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Jiaxin Liu
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Tongbin Lin
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xinghong Liu
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Shuchang Zhang
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xianhuai Yue
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xiaoli Zhang
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
| | - Xiangfang Zeng
- State Key Laboratory of Animal Nutrition, Ministry of Agriculture and Rural Affairs Feed Industry Center, China Agricultural University, Beijing, China
| | - Man Ren
- Anhui Provincial Key Laboratory of Animal Nutritional Regulation and Health, College of Animal Science, Anhui Science and Technology University, Fengyang, China
| | - Wutai Guan
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China
| | - Shihai Zhang
- Guangdong Province Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou, 510642, China.
- College of Animal Science and National Engineering Research Center for Breeding Swine Industry, South China Agricultural University, Guangzhou, 510642, China.
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, China.
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2
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Busic-Pavlek I, Dumic-Cule I, Kovacevic L, Milosevic M, Delimar P, Korsa L, Marusic Z, Prutki M. Calcium-Sensing Receptor Expression in Breast Cancer. Int J Mol Sci 2023; 24:11678. [PMID: 37511437 PMCID: PMC10380606 DOI: 10.3390/ijms241411678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The calcium-sensing receptor (CaSR) plays a crucial role in maintaining the balance of calcium in the body. Altered signaling through the CaSR has been linked to the development of various tumors, such as colorectal and breast tumors. This retrospective study enrolled 79 patients who underwent surgical removal of invasive breast carcinoma of no special type (NST) to explore the expression of the CaSR in breast cancer. The patients were categorized based on age, tumor size, hormone receptor status, HER2 status, Ki-67 proliferation index, tumor grade, and TNM staging. Immunohistochemistry was conducted on core needle biopsy samples to assess CaSR expression. The results revealed a positive correlation between CaSR expression and tumor size, regardless of the tumor surrogate subtype (p = 0.001). The expression of ER exhibited a negative correlation with CaSR expression (p = 0.033). In contrast, a positive correlation was observed between CaSR expression and the presence of HER2 receptors (p = 0.002). Increased CaSR expression was significantly associated with lymph node involvement and the presence of distant metastasis (p = 0.001 and p = 0.038, respectively). CaSR values were significantly higher in the patients with increased Ki-67 (p = 0.042). Collectively, higher CaSR expression in breast cancer could suggest a poor prognosis and treatment outcome regardless of the breast cancer subtype.
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Affiliation(s)
- Iva Busic-Pavlek
- Clinical Department of Diagnostic and Interventional Radiology, University Hospital Centre Split, Spinciceva 1, 21000 Split, Croatia
| | - Ivo Dumic-Cule
- Clinical Department of Diagnostic and Interventional Radiology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
- Department of Nursing, University North, 104 Brigade 3, 42000 Varazdin, Croatia
| | - Lucija Kovacevic
- Clinical Department of Diagnostic and Interventional Radiology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
| | - Milan Milosevic
- Department of Environmental Health and Occupational and Sports Medicine, Andrija Stampar School of Public Health, Rockfellerova 4, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, Salata 3, 10000 Zagreb, Croatia
| | - Petra Delimar
- Clinical Department of Diagnostic and Interventional Radiology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
| | - Lea Korsa
- Clinical Department of Pathology and Cytology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
| | - Zlatko Marusic
- Clinical Department of Pathology and Cytology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
| | - Maja Prutki
- Clinical Department of Diagnostic and Interventional Radiology, University Hospital Centre Zagreb, Kispaticeva 12, 10000 Zagreb, Croatia
- School of Medicine, University of Zagreb, Salata 3, 10000 Zagreb, Croatia
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3
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Neville MC, Demerath EW, Hahn-Holbrook J, Hovey RC, Martin-Carli J, McGuire MA, Newton ER, Rasmussen KM, Rudolph MC, Raiten DJ. Parental factors that impact the ecology of human mammary development, milk secretion, and milk composition-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 1. Am J Clin Nutr 2023; 117 Suppl 1:S11-S27. [PMID: 37173058 PMCID: PMC10232333 DOI: 10.1016/j.ajcnut.2022.11.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 05/15/2023] Open
Abstract
The goal of Working Group 1 in the Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN) Project was to outline factors influencing biological processes governing human milk secretion and to evaluate our current knowledge of these processes. Many factors regulate mammary gland development in utero, during puberty, in pregnancy, through secretory activation, and at weaning. These factors include breast anatomy, breast vasculature, diet, and the lactating parent's hormonal milieu including estrogen, progesterone, placental lactogen, cortisol, prolactin, and growth hormone. We examine the effects of time of day and postpartum interval on milk secretion, along with the role and mechanisms of lactating parent-infant interactions on milk secretion and bonding, with particular attention to the actions of oxytocin on the mammary gland and the pleasure systems in the brain. We then consider the potential effects of clinical conditions including infection, pre-eclampsia, preterm birth, cardiovascular health, inflammatory states, mastitis, and particularly, gestational diabetes and obesity. Although we know a great deal about the transporter systems by which zinc and calcium pass from the blood stream into milk, the interactions and cellular localization of transporters that carry substrates such as glucose, amino acids, copper, and the many other trace metals present in human milk across plasma and intracellular membranes require more research. We pose the question of how cultured mammary alveolar cells and animal models can help answer lingering questions about the mechanisms and regulation of human milk secretion. We raise questions about the role of the lactating parent and the infant microbiome and the immune system during breast development, secretion of immune molecules into milk, and protection of the breast from pathogens. Finally, we consider the effect of medications, recreational and illicit drugs, pesticides, and endocrine-disrupting chemicals on milk secretion and composition, emphasizing that this area needs much more research attention.
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Affiliation(s)
- Margaret C Neville
- Department of Obstetrics and Gynecology, University of Colorado, Aurora, CO, USA.
| | - Ellen W Demerath
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, United States
| | - Jennifer Hahn-Holbrook
- Department of Psychological Sciences, University of California Merced, Merced, CA, United States
| | - Russell C Hovey
- Department of Animal Science, University of California Davis, Davis, CA, United States
| | - Jayne Martin-Carli
- Department of Pediatrics, University of Colorado, Aurora, CO, United States
| | - Mark A McGuire
- Idaho Agricultural Experiment Station, University of Idaho, Moscow, ID, United States
| | - Edward R Newton
- Department of Obstetrics and Gynecology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Kathleen M Rasmussen
- Nancy Schlegel Meinig Professor of Maternal and Child Nutrition, Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Michael C Rudolph
- The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Daniel J Raiten
- Pediatric Growth and Nutrition Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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4
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Athonvarangkul D, Wysolmerski JJ. Crosstalk within a brain-breast-bone axis regulates mineral and skeletal metabolism during lactation. Front Physiol 2023; 14:1121579. [PMID: 36875035 PMCID: PMC9979219 DOI: 10.3389/fphys.2023.1121579] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 01/27/2023] [Indexed: 02/18/2023] Open
Abstract
To support the increased calcium demands for milk production during lactation, a dramatic and reversible physiological response occurs to alter bone and mineral metabolism. This coordinated process involves a brain-breast-bone axis that integrates hormonal signals that allow for adequate calcium delivery to milk yet also protects the maternal skeletal from excessive bone loss or decreases in bone quality or function. Here, we review the current knowledge on the crosstalk between the hypothalamus, mammary gland, and skeleton during lactation. We discuss the rare entity of pregnancy and lactation associated osteoporosis and consider how the physiology of bone turnover in lactation may impact the pathophysiology of postmenopausal osteoporosis. Further understanding of the regulators of bone loss during lactation, particularly in humans, may provide insights into new therapies for osteoporosis and other diseases of excess bone loss.
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Affiliation(s)
- Diana Athonvarangkul
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States
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5
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Hannan FM, Elajnaf T, Vandenberg LN, Kennedy SH, Thakker RV. Hormonal regulation of mammary gland development and lactation. Nat Rev Endocrinol 2023; 19:46-61. [PMID: 36192506 DOI: 10.1038/s41574-022-00742-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/17/2022] [Indexed: 12/14/2022]
Abstract
Lactation is critical to infant short-term and long-term health and protects mothers from breast cancer, ovarian cancer and type 2 diabetes mellitus. The mammary gland is a dynamic organ, regulated by the coordinated actions of reproductive and metabolic hormones. These hormones promote gland development from puberty onwards and induce the formation of a branched, epithelial, milk-secreting organ by the end of pregnancy. Progesterone withdrawal following placental delivery initiates lactation, which is maintained by increased pituitary secretion of prolactin and oxytocin, and stimulated by infant suckling. After weaning, local cytokine production and decreased prolactin secretion trigger large-scale mammary cell loss, leading to gland involution. Here, we review advances in the molecular endocrinology of mammary gland development and milk synthesis. We discuss the hormonal functions of the mammary gland, including parathyroid hormone-related peptide secretion that stimulates maternal calcium mobilization for milk synthesis. We also consider the hormonal composition of human milk and its associated effects on infant health and development. Finally, we highlight endocrine and metabolic diseases that cause lactation insufficiency, for example, monogenic disorders of prolactin and prolactin receptor mutations, maternal obesity and diabetes mellitus, interventions during labour and delivery, and exposure to endocrine-disrupting chemicals such as polyfluoroalkyl substances in consumer products and other oestrogenic compounds.
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Affiliation(s)
- Fadil M Hannan
- Larsson-Rosenquist Foundation Oxford Centre for the Endocrinology of Human Lactation, Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK.
| | - Taha Elajnaf
- Larsson-Rosenquist Foundation Oxford Centre for the Endocrinology of Human Lactation, Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK
| | - Laura N Vandenberg
- Department of Environmental Health Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Stephen H Kennedy
- Larsson-Rosenquist Foundation Oxford Centre for the Endocrinology of Human Lactation, Nuffield Department of Women's & Reproductive Health, University of Oxford, Oxford, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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6
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Grinman DY, Boras-Granic K, Takyar FM, Dann P, Hens JR, Marmol C, Lee J, Choi J, Chodosh LA, Sola MEG, Wysolmerski JJ. PTHrP induces STAT5 activation, secretory differentiation and accelerates mammary tumor development. Breast Cancer Res 2022; 24:30. [PMID: 35440032 PMCID: PMC9020078 DOI: 10.1186/s13058-022-01523-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/29/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Parathyroid hormone-related protein (PTHrP) is required for embryonic breast development and has important functions during lactation, when it is produced by alveolar epithelial cells and secreted into the maternal circulation to mobilize skeletal calcium used for milk production. PTHrP is also produced by breast cancers, and GWAS studies suggest that it influences breast cancer risk. However, the exact functions of PTHrP in breast cancer biology remain unsettled. METHODS We developed a tetracycline-regulated, MMTV (mouse mammary tumor virus)-driven model of PTHrP overexpression in mammary epithelial cells (Tet-PTHrP mice) and bred these mice with the MMTV-PyMT (polyoma middle tumor-antigen) breast cancer model to analyze the impact of PTHrP overexpression on normal mammary gland biology and in breast cancer progression. RESULTS Overexpression of PTHrP in luminal epithelial cells caused alveolar hyperplasia and secretory differentiation of the mammary epithelium with milk production. This was accompanied by activation of Stat5 and increased expression of E74-like factor-5 (Elf5) as well as a delay in post-lactation involution. In MMTV-PyMT mice, overexpression of PTHrP (Tet-PTHrP;PyMT mice) shortened tumor latency and accelerated tumor growth, ultimately reducing overall survival. Tumors overproducing PTHrP also displayed increased expression of nuclear pSTAT5 and Elf5, increased expression of markers of secretory differentiation and milk constituents, and histologically resembled secretory carcinomas of the breast. Overexpression of PTHrP within cells isolated from tumors, but not PTHrP exogenously added to cell culture media, led to activation of STAT5 and milk protein gene expression. In addition, neither ablating the Type 1 PTH/PTHrP receptor (PTH1R) in epithelial cells nor treating Tet-PTHrP;PyMT mice with an anti-PTH1R antibody prevented secretory differentiation or altered tumor latency. These data suggest that PTHrP acts in a cell-autonomous, intracrine manner. Finally, expression of PTHrP in human breast cancers is associated with expression of genes involved in milk production and STAT5 signaling. CONCLUSIONS Our study suggests that PTHrP promotes pathways leading to secretory differentiation and proliferation in both normal mammary epithelial cells and in breast tumor cells.
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Affiliation(s)
- Diego Y Grinman
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, 300 Cedar Street, TAC S120, Box 208020, New Haven, CT, 06520-8020, USA.
| | - Kata Boras-Granic
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, 300 Cedar Street, TAC S120, Box 208020, New Haven, CT, 06520-8020, USA
| | - Farzin M Takyar
- Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Pamela Dann
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, 300 Cedar Street, TAC S120, Box 208020, New Haven, CT, 06520-8020, USA
| | - Julie R Hens
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, 300 Cedar Street, TAC S120, Box 208020, New Haven, CT, 06520-8020, USA
| | | | - Jongwon Lee
- Brain Korea 21 Plus Project for Biomedical Science, Korea University College of Medicine, Seoul, Korea
| | - Jungmin Choi
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Korea.,Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Lewis A Chodosh
- Department of Cancer Biology, Perlman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Martin E Garcia Sola
- Departamento de Fisiología y Biología Molecular y Celular, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIByNE), CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - John J Wysolmerski
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale School of Medicine, 300 Cedar Street, TAC S120, Box 208020, New Haven, CT, 06520-8020, USA
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Ansari N, Isojima T, Crimeen-Irwin B, Poulton IJ, McGregor NE, Ho PWM, Forwood MR, Kovacs CS, Dimitriadis E, Gooi JH, Martin TJ, Sims NA. Dmp1Cre-directed knockdown of parathyroid hormone-related protein (PTHrP) in murine decidua is associated with a life-long increase in bone mass, width, and strength in male progeny. J Bone Miner Res 2021; 36:1999-2016. [PMID: 34101894 DOI: 10.1002/jbmr.4388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 05/14/2021] [Accepted: 06/02/2021] [Indexed: 12/28/2022]
Abstract
Parathyroid hormone-related protein (PTHrP, gene name Pthlh) is a pleiotropic regulator of tissue homeostasis. In bone, Dmp1Cre-targeted PTHrP deletion in osteocytes causes osteopenia and impaired cortical strength. We report here that this outcome depends on parental genotype. In contrast to our previous report using mice bred from heterozygous (flox/wild type) Dmp1Cre.Pthlhf/w parents, adult (16-week-old and 26-week-old) flox/flox (f/f) Dmp1Cre.Pthlhf/f mice from homozygous parents (Dmp1Cre.Pthlhf/f(hom) ) have stronger bones, with 40% more trabecular bone mass and 30% greater femoral width than controls. This greater bone size was observed in Dmp1Cre.Pthlhf/f(hom) mice as early as 12 days of age, when greater bone width was also found in male and female Dmp1Cre.Pthlhf/f(hom) mice compared to controls, but not in gene-matched mice from heterozygous parents. This suggested a maternal influence on skeletal size prior to weaning. Although Dmp1Cre has previously been reported to cause gene recombination in mammary gland, milk PTHrP protein levels were normal. The wide-bone phenotype was also noted in utero: Dmp1Cre.Pthlhf/f(hom) embryonic femurs were more mineralized and wider than controls. Closer examination revealed that Dmp1Cre caused PTHrP recombination in placenta, and in the maternal-derived decidual layer that resides between the placenta and the uterus. Decidua from mothers of Dmp1Cre.Pthlhf/f(hom) mice also exhibited lower PTHrP levels by immunohistochemistry and were smaller than controls. We conclude that Dmp1Cre leads to gene recombination in decidua, and that decidual PTHrP might, through an influence on decidual cells, limit embryonic bone radial growth. This suggests a maternal-derived developmental origin of adult bone strength. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Niloufar Ansari
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Tsuyoshi Isojima
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Department of Pediatrics, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Ingrid J Poulton
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Narelle E McGregor
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Patricia W M Ho
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Mark R Forwood
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, Queensland, Australia
| | - Christopher S Kovacs
- Faculty of Medicine - Endocrinology, Memorial University of Newfoundland, St John's, Newfoundland, Canada
| | - Evdokia Dimitriadis
- Department of Obstetrics and Gynecology, University of Melbourne, The Women's Hospital, Melbourne, Victoria, Australia
| | - Jonathan H Gooi
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia.,Bio21 Molecular Science and Biotechnology Institute, Parkville, Victoria, Australia
| | - T John Martin
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
| | - Natalie A Sims
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Fitzroy, Victoria, Australia
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Immler M, Failing K, Gärtner T, Wehrend A, Donat K. Associations between the metabolic status of the cow and colostrum quality as determined by Brix refractometry. J Dairy Sci 2021; 104:10131-10142. [PMID: 34253369 DOI: 10.3168/jds.2020-19812] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/28/2021] [Indexed: 11/19/2022]
Abstract
Supplying newborn calves with immunoglobins is critical for their health and a daily challenge in the dairy industry. Among various factors determining colostrum quality, the prepartum metabolic status of the cow might be of particular importance. The objective of this observational cross-sectional study was to evaluate relationships between cow-level variables and the colostrum quality as determined by Brix refractometry. A total of 873 cows of varying breed and parity from 124 German dairy herds were included in the study, and blood and urine samples were taken 3 to 1 wk before the expected calving date. Effectively, samples were collected on average 8.2 d (geometric mean) before calving, ranging from 2 to 45 d. The final variable set included body condition score, lameness score, breed, parity, vaccination of the cow, the activity of glutamate dehydrogenase and aspartate aminotransferase, the urine concentration of creatinine, net acid-base excretion, the serum concentration of cholesterol and calcium, and the difference in albumin and total protein concentration. Generalized linear mixed effects regression models with hierarchically structured random effects (cow within herd) using the maximum likelihood method were fitted to the data to identify associations between the Brix value as an outcome and cow-level variables as predictors. Cows entering second parity had lower Brix values compared with cows entering third or greater parity, and prepartum vaccination of cows led to higher Brix values compared with nonvaccinated cows. Cows with a moderate to high lameness score had lower Brix values than cows with low-grade lameness. An increase of glutamate dehydrogenase serum activity and serum calcium concentration were associated with lower Brix values, whereas an increase in the difference of total protein and albumin serum concentration led to higher Brix values. In conclusion, the metabolic health of the cow affects colostrum quality and may cause failure of passive immunoglobulin transfer as well as impaired calf health.
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Affiliation(s)
- Manuela Immler
- Animal Health Service, Thuringian Animal Diseases Fund, Victor-Goerttler-Straße 4, 07745 Jena, Germany
| | - Klaus Failing
- Unit for Biomathematics and Data Processing, Veterinary Faculty, Justus-Liebig-University Giessen, Frankfurter Str. 95, 35392 Giessen, Germany
| | - Tanja Gärtner
- Animal Health Service, Thuringian Animal Diseases Fund, Victor-Goerttler-Straße 4, 07745 Jena, Germany
| | - Axel Wehrend
- Clinic for Obstetrics, Gynecology and Andrology with Veterinary Ambulance, Justus-Liebig-University Giessen, Frankfurter Str. 106, 35392 Giessen, Germany
| | - Karsten Donat
- Animal Health Service, Thuringian Animal Diseases Fund, Victor-Goerttler-Straße 4, 07745 Jena, Germany; Clinic for Obstetrics, Gynecology and Andrology with Veterinary Ambulance, Justus-Liebig-University Giessen, Frankfurter Str. 106, 35392 Giessen, Germany.
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9
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Capozzi A, Scambia G, Lello S. Bone metabolism in pregnancy and lactation. Minerva Obstet Gynecol 2021; 73:697-703. [PMID: 34180616 DOI: 10.23736/s2724-606x.21.04905-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Different hormonal mechanisms regulate bone metabolism during pregnancy and lactation. In both those periods of life, a fine modulation of calcium metabolism is necessary to meet the needs of foetus and newborn. METHODS We review scientific literature on the topic "osteoporosis", "pregnancy" and "lactation", evaluating the most relevant data from original articles, reviews and meta-analyses. EVIDENCE SYNTHESIS Pregnancy- and lactation-associated bone loss and related fractures rarely occur and, generally, clinicians have to manage it case to case, since there is not a unique guideline. Fortunately, bone mineral density (BMD) usually tends to recover within 12 months after weaning, thus, it could be reasonable waiting of assessing the effective magnitude of bone mass regain before starting any pharmacological treatment. CONCLUSIONS Osteoporosis and/or fragility fractures remain uncommon events associated with gestation and/or breastfeeding. The management of bone loss and/or fractures during those periods is generally conservative and a tailored approach is advisable in the absence of any specific recommendation in this field.
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Affiliation(s)
- Anna Capozzi
- Department of Women and Child Health, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy -
| | - Giovanni Scambia
- Department of Women and Child Health, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | - Stefano Lello
- Department of Women and Child Health, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
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10
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Connelly MK, Weaver SR, Kuehnl JM, Fricke HP, Klister M, Hernandez L. Elevated serotonin coordinates mammary metabolism in dairy cows. Physiol Rep 2021; 9:e14798. [PMID: 33835711 PMCID: PMC8034258 DOI: 10.14814/phy2.14798] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
Serotonin plays a diverse role in maternal and mammary metabolism. Recent research in the dairy cow has shown a relationship between serotonin and calcium, with increased serotonin concentrations improving calcium homeostasis in the peri‐partum dairy cow. Therefore, the objective was to elucidate how administration of 5‐hydroxy‐l‐tryptophan (5‐HTP), the immediate precursor to serotonin, altered serotonin and calcium metabolism in lactating dairy cows. Twelve mid‐late lactation multiparous cows were blocked by parity, production and days in milk and allocated to a daily intravenous infusion of (i) 1.5 mg/kg of 5‐HTP (n = 6) or (ii) saline (n = 6) for 3 consecutive days. Milk samples were collected daily. Blood samples were collected before and after each infusion with mammary biopsies and blood samples collected at 48, 56, and 72 h relative to termination of first infusion. Infusion of 5‐HTP increased (p = 0.001) circulating serotonin concentrations and decreased blood calcium via a transient hypocalcemia immediately after each infusion (p = 0.02). Treatment with 5‐HTP increased milk calcium concentrations (p = 0.02) and calcium release‐activated channel protein 1 (ORAI1) mRNA at 56 h and protein at 48 h relative to termination of first infusion (p = 0.008 and p = 0.09, respectively). Fifty‐six hours from termination of the first infusion mRNA of parathyroid hormone‐related protein and mammary serotonin content were increased relative to control (p = 0.03 and p = 0.05, respectively). These findings demonstrate the ability of 5‐HTP infusion to increase circulating serotonin concentrations and alter endocrine and mammary autocrine/paracrine calcium and serotonin metabolism in the lactating dairy cow.
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Affiliation(s)
- Meghan K Connelly
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
| | - Samantha R Weaver
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
| | - Jordan M Kuehnl
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
| | - Hannah P Fricke
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
| | - Marisa Klister
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
| | - Laura Hernandez
- Department of Animal and Dairy Sciences, University of Wisconsin, Madison, WI, USA
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11
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Grinman D, Athonvarungkul D, Wysolmerski J, Jeong J. Calcium Metabolism and Breast Cancer: Echoes of Lactation? ACTA ACUST UNITED AC 2020; 15:63-70. [PMID: 33299957 DOI: 10.1016/j.coemr.2020.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lactation requires a series of adaptations in maternal calcium and bone metabolism to ensure a steady supply of calcium to the lactating mammary gland. The alterations in systemic metabolism are accompanied by alterations in the expression of calcium receptors, channels, binding proteins, pumps and transporters in mammary epithelial cells to increase the uptake of calcium from the extracellular fluid and to transport it into milk. Intracellular calcium regulates signaling pathways that mediate changes in cell proliferation, differentiation and death and many of the molecules involved in supporting and coordinating calcium secretion into milk are re-expressed and redeployed to support malignant behavior in breast cancer cells. In this article, we review adaptations of systemic calcium homeostasis during lactation, as well as the mechanisms of milk calcium transport. We then discuss how reactivation of these pathways contributes to the pathophysiology of breast cancer.
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Affiliation(s)
- Diego Grinman
- Section of Endocrinology and Metabolism, Department of Medicine, Yale School of Medicine
| | - Diana Athonvarungkul
- Section of Endocrinology and Metabolism, Department of Medicine, Yale School of Medicine
| | - John Wysolmerski
- Section of Endocrinology and Metabolism, Department of Medicine, Yale School of Medicine
| | - Jaekwang Jeong
- Section of Endocrinology and Metabolism, Department of Medicine, Yale School of Medicine
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12
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Otto PI, Guimarães SEF, Calus MPL, Vandenplas J, Machado MA, Panetto JCC, da Silva MVGB. Single-step genome-wide association studies (GWAS) and post-GWAS analyses to identify genomic regions and candidate genes for milk yield in Brazilian Girolando cattle. J Dairy Sci 2020; 103:10347-10360. [PMID: 32896396 DOI: 10.3168/jds.2019-17890] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 06/19/2020] [Indexed: 12/15/2022]
Abstract
Milk production is economically important to the Brazilian agribusiness, and the majority of the country's milk production derives from Girolando (Gir × Holstein) cows. This study aimed to identify quantitative trait loci (QTL) and candidate genes associated with 305-d milk yield (305MY) in Girolando cattle. In addition, we investigated the SNP-specific variances for Holstein and Gir breeds of origin within the sequence of candidate genes. A single-step genomic BLUP procedure was used to identify QTL associated with 305MY, and the most likely candidate genes were identified through follow-up analyses. Genomic breeding values specific for Holstein and Gir were estimated in the Girolando animals using a model that uses breed-specific partial relationship matrices, which were converted to breed of origin SNP effects. Differences between breed of origin were evaluated by comparing estimated SNP variances between breeds. From 10 genome regions explaining most additive genetic variance for 305MY in Girolando cattle, 7 candidate genes were identified on chromosomes 1, 4, 6, and 26. Within the sequence of these 7 candidate genes, Gir breed of origin SNP alleles showed the highest genetic variance. These results indicated QTL regions that could be further explored in genomic selection panels and which may also help in understanding the gene mechanisms involved in milk production in the Girolando breed.
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Affiliation(s)
- Pamela I Otto
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Simone E F Guimarães
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Mario P L Calus
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Jeremie Vandenplas
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Marco A Machado
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - João Cláudio C Panetto
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
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13
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Das S, Clézardin P, Kamel S, Brazier M, Mentaverri R. The CaSR in Pathogenesis of Breast Cancer: A New Target for Early Stage Bone Metastases. Front Oncol 2020; 10:69. [PMID: 32117726 PMCID: PMC7013091 DOI: 10.3389/fonc.2020.00069] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/15/2020] [Indexed: 12/11/2022] Open
Abstract
The Ca2+-sensing receptor (CaSR) is a class-C G protein-coupled receptor which plays a pivotal role in calciotropic processes, primarily in regulating parathyroid hormone secretion to maintain systemic calcium homeostasis. Among its non-calciotropic roles, where the CaSR sits at the intersection of myriad processes, it has steadily garnered attention as an oncogene or tumor suppressor in different organs. In maternal breast tissues the CaSR promotes lactation but in breast cancer it acts as an oncoprotein and has been shown to drive the pathogenesis of skeletal metastases from breast cancer. Even though research has made great strides in treating primary breast cancer, there is an unmet need when it comes to treatment of metastatic breast cancer. This review focuses on how the CaSR leads to the pathogenesis of breast cancer by contrasting its role in healthy tissues and tumorigenesis, and by drawing brief parallels with the tissues where it has been implicated as an oncogene. A class of compounds called calcilytics, which are CaSR antagonists, have also been surveyed in the instances where they have been used to target the receptor in cancerous tissues and constitute a proof of principle for repurposing them. Current clinical therapies for treating bone metastases from breast cancer are limited to targeting osteoclasts and a deeper understanding of the CaSR signaling nexus in this context can bolster them or lead to novel therapeutic interventions.
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Affiliation(s)
- Souvik Das
- MP3CV, EA7517, CURS, University of Picardie Jules Verne, Amiens, France
| | - Philippe Clézardin
- INSERM, Research Unit UMR_S1033, LyOS, Faculty of Medicine Lyon-Est, University of Lyon 1, Lyon, France
- Department of Oncology and Metabolism, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Said Kamel
- MP3CV, EA7517, CURS, University of Picardie Jules Verne, Amiens, France
- Department of Biochemistry, Amiens-Picardie University Hospital, Amiens, France
- Faculty of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Michel Brazier
- MP3CV, EA7517, CURS, University of Picardie Jules Verne, Amiens, France
- Department of Biochemistry, Amiens-Picardie University Hospital, Amiens, France
- Faculty of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Romuald Mentaverri
- MP3CV, EA7517, CURS, University of Picardie Jules Verne, Amiens, France
- Department of Biochemistry, Amiens-Picardie University Hospital, Amiens, France
- Faculty of Pharmacy, University of Picardie Jules Verne, Amiens, France
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14
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Ryan BA, Kovacs CS. Calciotropic and phosphotropic hormones in fetal and neonatal bone development. Semin Fetal Neonatal Med 2020; 25:101062. [PMID: 31786156 DOI: 10.1016/j.siny.2019.101062] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There are remarkable differences in bone and mineral metabolism between the fetus and adult. The fetal mineral supply is from active transport across the placenta. Calcium, phosphorus, and magnesium circulate at higher levels in the fetus compared to the mother. These high concentrations enable the skeleton to accrete required minerals before birth. Known key regulators in the adult include parathyroid hormone (PTH), calcitriol, fibroblast growth factor-23, calcitonin, and the sex steroids. But during fetal life, PTH plays a lesser role while the others appear to be unimportant. Instead, PTH-related protein (PTHrP) plays a critical role. After birth, serum calcium falls and phosphorus rises, which trigger an increase in PTH and a subsequent rise in calcitriol. The intestines become the main source of mineral supply while the kidneys reabsorb filtered minerals. This striking developmental switch is triggered by loss of the placenta, onset of breathing, and the drop in serum calcium.
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Affiliation(s)
- Brittany A Ryan
- Faculty of Medicine - Endocrinology, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Christopher S Kovacs
- Faculty of Medicine - Endocrinology, Memorial University of Newfoundland, St. John's, NL, Canada.
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15
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Lotinun S, Ishihara Y, Nagano K, Kiviranta R, Carpentier VT, Neff L, Parkman V, Ide N, Hu D, Dann P, Brooks D, Bouxsein ML, Wysolmerski J, Gori F, Baron R. Cathepsin K-deficient osteocytes prevent lactation-induced bone loss and parathyroid hormone suppression. J Clin Invest 2019; 129:3058-3071. [PMID: 31112135 DOI: 10.1172/jci122936] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Lactation induces bone loss to provide sufficient calcium in the milk, a process that involves osteoclastic bone resorption but also osteocytes and perilacunar resorption. The exact mechanisms by which osteocytes contribute to bone loss remain elusive. Osteocytes express genes required in osteoclasts for bone resorption, including cathepsin K (Ctsk), and lactation elevates their expression. We show that Ctsk deletion in osteocytes prevented the increase in osteocyte lacunar area seen during lactation, as well as the effects of lactation to increase osteoclast numbers and decrease trabecular bone volume, cortical thickness and mechanical properties. In addition, Ctsk deletion in osteocytes increased bone Parathyroid Hormone related Peptide (PTHrP), prevented the decrease in serum Parathyroid Hormone (PTH) induced by lactation, but amplified the increase in serum 1,25(OH)2D. The net result of these changes is to maintain serum and milk calcium levels in the normal range, ensuring normal offspring skeletal development. Our studies confirm the fundamental role of osteocytic perilacunar remodeling in physiological states of lactation and provides genetic evidence that osteocyte-derived Ctsk contributes not only to osteocyte perilacunar remodeling, but also to the regulation of PTH, PTHrP, 1,25-Dyhydroxyvitamin D (1,25(OH)2D), osteoclastogenesis and bone loss in response to the high calcium demand associated with lactation.
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Affiliation(s)
- Sutada Lotinun
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA.,Department of Physiology and Skeletal Disorders Research Unit, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Yoshihito Ishihara
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Kenichi Nagano
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Riku Kiviranta
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA.,Departments of Medical Biochemistry and Genetics and Medicine, University of Turku, Turku, Finland
| | - Vincent T Carpentier
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Lynn Neff
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Virginia Parkman
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Noriko Ide
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Dorothy Hu
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Pamela Dann
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Daniel Brooks
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Mary L Bouxsein
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - John Wysolmerski
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Francesca Gori
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Roland Baron
- Division of Bone and Mineral Research, Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA.,Harvard Medical School, Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts, USA
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16
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Modarressi T, Levine MA, Tchou J, Khan AN. Gestational Gigantomastia Complicated by PTHrP-Mediated Hypercalcemia. J Clin Endocrinol Metab 2018; 103:3124-3130. [PMID: 30032172 DOI: 10.1210/jc.2018-01181] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/12/2018] [Indexed: 02/13/2023]
Abstract
CONTEXT Gestational gigantomastia is an uncommon condition characterized by abnormal and excessive growth of breast tissue during an otherwise uncomplicated pregnancy. Gestational gigantomastia may be accompanied by hypercalcemia, which in some cases has been associated with elevated serum levels of PTHrP. The source of the PTHrP in these cases has been suggested to be the enlarged breasts. OBJECTIVE To describe the rapid resolution of hypercalcemia and normalization of serum PTHrP after elective termination of pregnancy, indicating that the placenta was the source of the PTHrP. DESIGN A retrospective analysis of clinical and biochemical data over a 2-year interval and review of literature. SETTING An academic medical center. PATIENT A 33-year-old G8P4 female who presented at week 8 of pregnancy with gestational gigantomastia and subsequently developed marked hypercalcemia at week 13. Serum levels of PTH were suppressed but circulating PTHrP was elevated. There was no history of hypercalcemia or significant breast growth during previous pregnancies. INTERVENTION Hypercalcemia was poorly responsive to IV saline, prednisone, calcitonin, and cinacalcet. She requested termination of pregnancy at week 20. RESULTS Serum levels of calcium, PTH, and PTHrP normalized within 48 hours of termination of pregnancy. CONCLUSION The rapid resolution of hypercalcemia after termination of pregnancy, despite persistent gigantomastia, provides evidence for a pathologic role of the placenta in the excess production of PTHrP, possibly through an as yet uncharacterized placenta-breast hormonal axis.
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Affiliation(s)
- Taher Modarressi
- Department of Endocrinology, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael A Levine
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Julia Tchou
- Abramson Cancer Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Division of Endocrine and Oncologic Surgery, Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amna N Khan
- Department of Endocrinology, Diabetes and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Section of Endocrinology, Philadelphia VA Medical Center, Philadelphia, Pennsylvania
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17
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Weaver SR, Fricke HP, Xie C, Lipinski RJ, Vezina CM, Charles JF, Hernandez LL. Peripartum Fluoxetine Reduces Maternal Trabecular Bone After Weaning and Elevates Mammary Gland Serotonin and PTHrP. Endocrinology 2018; 159:2850-2862. [PMID: 29893816 PMCID: PMC6456925 DOI: 10.1210/en.2018-00279] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/04/2018] [Indexed: 12/28/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) have been linked to osteopenia and fracture risk; however, their long-term impact on bone health is not well understood. SSRIs are widely prescribed to pregnant and breastfeeding women who might be at particular risk of bone pathology because lactation is associated with considerable maternal bone loss. We used microCT and molecular approaches to test whether the SSRI fluoxetine, administered to C57BL/6 mice from conception through the end of lactation, causes persistent maternal bone loss. We found that peripartum fluoxetine increases serum calcium and reduces circulating markers of bone formation during lactation but does not affect osteoclastic resorption. Peripartum fluoxetine exposure also enhances mammary gland endocrine function during lactation by increasing synthesis of serotonin and PTHrP, a hormone that liberates calcium for milk synthesis and reduces bone mineral volume. Peripartum fluoxetine exposure reduces the trabecular bone volume fraction at 3 months after weaning. These findings raise new questions about the long-term consequences of peripartum SSRI use on maternal health.
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Affiliation(s)
- Samantha R Weaver
- Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin
| | - Hannah P Fricke
- Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin
| | - Cynthia Xie
- Department of Orthopedics, Brigham and Women’s Hospital, Boston, Massachusetts
- Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Robert J Lipinski
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Chad M Vezina
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Julia F Charles
- Department of Orthopedics, Brigham and Women’s Hospital, Boston, Massachusetts
- Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Laura L Hernandez
- Department of Dairy Science, University of Wisconsin-Madison, Madison, Wisconsin
- Correspondence: Laura L. Hernandez, PhD, Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, Wisconsin 53706. E-mail:
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18
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Weaver SR, Hernandez LL. Could use of Selective Serotonin Reuptake Inhibitors During Lactation Cause Persistent Effects on Maternal Bone? J Mammary Gland Biol Neoplasia 2018; 23:5-25. [PMID: 29603039 DOI: 10.1007/s10911-018-9390-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/13/2018] [Indexed: 02/07/2023] Open
Abstract
The lactating mammary gland elegantly coordinates maternal homeostasis to provide calcium for milk. During lactation, the monoamine serotonin regulates the synthesis and release of various mammary gland-derived factors, such as parathyroid hormone-related protein (PTHrP), to stimulate bone resorption. Recent evidence suggests that bone mineral lost during prolonged lactation is not fully recovered following weaning, possibly putting women at increased risk of fracture or osteoporosis. Selective Serotonin Reuptake Inhibitor (SSRI) antidepressants have also been associated with reduced bone mineral density and increased fracture risk. Therefore, SSRI exposure while breastfeeding may exacerbate lactational bone loss, compromising long-term bone health. Through an examination of serotonin and calcium homeostasis during lactation, lactational bone turnover and post-weaning recovery of bone mineral, and the effect of peripartum depression and SSRI on the mammary gland and bone, this review will discuss the hypothesis that peripartum SSRI exposure causes persistent reductions in bone mineral density through mammary-derived PTHrP signaling with bone.
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Affiliation(s)
- Samantha R Weaver
- Endocrine and Reproductive Physiology Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Laura L Hernandez
- Department of Dairy Science, University of Wisconsin-Madison, Madison, WI, USA.
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19
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Hernandez LL. TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Serotonin and the regulation of calcium transport in dairy cows. J Anim Sci 2018; 95:5711-5719. [PMID: 29293773 DOI: 10.2527/jas2017.1673] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The mammary gland regulates maternal metabolism during lactation. Numerous factors within the tissue send signals to shift nutrients to the mammary gland for milk synthesis. Serotonin is a monoamine that has been well documented to regulate several aspects of lactation among species. Maintenance of maternal calcium homeostasis during lactation is a highly evolved process that is elegantly regulated by the interaction of the mammary gland with the bone, gut, and kidney tissues. It is well documented that dietary calcium is insufficient to maintain maternal calcium concentrations during lactation, and mammals must rely on bone resorption to maintain normocalcemia. Our recent work focused on the ability of the mammary gland to function as an accessory parathyroid gland during lactation. It was demonstrated that serotonin acts to stimulate parathyroid hormone-related protein (PTHrP) in the mammary gland during lactation. The main role of mammary-derived PTHrP during mammalian lactation is to stimulate bone resorption to maintain maternal calcium homeostasis during lactation. In addition to regulating PTHrP, it was shown that serotonin appears to directly affect calcium transporters and pumps in the mammary gland. Our current working hypothesis regarding the control of calcium during lactation is as follows: serotonin directly stimulates PTHrP production in the mammary gland through interaction with the sonic hedgehog signaling pathway. Simultaneously, serotonin directly increases calcium movement into the mammary gland and, subsequently, milk. These 2 direct actions of serotonin combine to induce a transient maternal hypocalcemia required to further stimulate PTHrP production and calcium mobilization from bone. Through these 2 routes, serotonin is able to improve maternal calcium concentrations. Furthermore, we have shown that Holstein and Jersey cows appear to regulate calcium in different manners and also respond differently to serotonergic stimulation of the calcium pathway. Our data in rodents and cows indicate that serotonin and calcium are working through a unique feedback loop with PTHrP during lactation to regulate milk calcium and maternal calcium homeostasis.
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20
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Macari S, Sharma LA, Wyatt A, da Silva JM, Dias GJ, Silva TA, Szawka RE, Grattan DR. Lactation induces increases in the RANK/RANKL/OPG system in maxillary bone. Bone 2018; 110:160-169. [PMID: 29382610 DOI: 10.1016/j.bone.2018.01.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 10/18/2022]
Abstract
The underlying causes of maxillary bone loss during lactation remain poorly understood. We evaluated the impact of lactation on physiological and mechanically-induced alveolar bone remodeling. Nulliparous non-lactating (N-LAC) and 21-day lactating (LAC) mice underwent mechanically-induced bone remodeling by orthodontic tooth movement (OTM). Micro-computed tomography (microCT) was performed in the maxilla, femur and vertebra. Tartrate-resistant-acid phosphatase (TRAP) and Masson's trichrome labelling was performed in the maxillary bone and gene expression was determined in the periodontal ligament. The effect of prolactin on osteoclast (OCL) and osteoblast (OBL) differentiation was also investigated in N-LAC and LAC mice. Lactation increased alveolar bone loss in the maxilla, femur and vertebra, while OTM was enhanced. The number of OCL and OBL was higher in the maxilla of LAC mice. OTM increased OCL in both groups; while OBL was increased only in N-LAC but not in LAC mice, in which cell numbers were already elevated. The alveolar bone loss during lactation was associated with increased expression of receptor activator of nuclear factor-KappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in the maxilla. OTM induced the same responses in N-LAC mice, whereas it had no further effect in LAC mice. Lactation enhanced differentiation of OCL and OBL from bone marrow cells, and prolactin recapitulated OCL differentiation in N-LAC mice. Thus, lactation increases physiological maxillary bone remodeling and OTM, and both require activation of RANK/RANKL/OPG system. These findings expand our knowledge of lactation-induced osteopenia and have possible impact on clinical practice regarding orthodontic treatments and dental implants in lactating women.
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Affiliation(s)
- Soraia Macari
- Departamento de Odontopediatria e Ortodontia, Faculdade de Odontologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
| | - Lavanya A Sharma
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Amanda Wyatt
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Janine Maíra da Silva
- Departamento de Clínica, Patologia e Cirurgia Odontológicas, Faculdade de Odontologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - George J Dias
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Tarcília A Silva
- Departamento de Clínica, Patologia e Cirurgia Odontológicas, Faculdade de Odontologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Raphael E Szawka
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - David R Grattan
- Department of Anatomy, University of Otago, Dunedin, New Zealand
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21
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Kim W, Wysolmerski JJ. Calcium-Sensing Receptor in Breast Physiology and Cancer. Front Physiol 2016; 7:440. [PMID: 27746743 PMCID: PMC5043011 DOI: 10.3389/fphys.2016.00440] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 09/16/2016] [Indexed: 12/31/2022] Open
Abstract
The calcium-sensing receptor (CaSR) is expressed in normal breast epithelial cells and in breast cancer cells. During lactation, activation of the CaSR in mammary epithelial cells increases calcium transport into milk and inhibits parathyroid hormone-related protein (PTHrP) secretion into milk and into the circulation. The ability to sense changes in extracellular calcium allows the lactating breast to actively participate in the regulation of systemic calcium and bone metabolism, and to coordinate calcium usage with calcium availability during milk production. Interestingly, as compared to normal breast cells, in breast cancer cells, the regulation of PTHrP secretion by the CaSR becomes rewired due to a switch in its G-protein usage such that activation of the CaSR increases instead of decreases PTHrP production. In normal cells the CaSR couples to Gαi to inhibit cAMP and PTHrP production, whereas in breast cancer cells, it couples to Gαs to stimulate cAMP and PTHrP production. Activation of the CaSR on breast cancer cells regulates breast cancer cell proliferation, death and migration, in part, by stimulating PTHrP production. In this article, we discuss the biology of the CaSR in the normal breast and in breast cancer, and review recent findings suggesting that the CaSR activates a nuclear pathway of PTHrP action that stimulates cellular proliferation and inhibits cell death, helping cancer cells adapt to elevated extracellular calcium levels. Understanding the diverse actions mediated by the CaSR may help us better understand lactation physiology, breast cancer progression and osteolytic bone metastases.
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Affiliation(s)
- Wonnam Kim
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine New Haven, CT, USA
| | - John J Wysolmerski
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine New Haven, CT, USA
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Sun F, Cao Y, Yu C, Wei X, Yao J. 1,25-Dihydroxyvitamin D3 modulates calcium transport in goat mammary epithelial cells in a dose- and energy-dependent manner. J Anim Sci Biotechnol 2016; 7:41. [PMID: 27471592 PMCID: PMC4964070 DOI: 10.1186/s40104-016-0101-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 07/12/2016] [Indexed: 12/14/2022] Open
Abstract
Background Calcium is a vital mineral and an indispensable component of milk for ruminants. The regulation of transcellular calcium transport by 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3, the active form of vitamin D) has been confirmed in humans and rodents, and regulators, including vitamin D receptor (VDR), calcium binding protein D9k (calbindin-D9k), plasma membrane Ca2+-ATPase 1b (PMCA1b), PMAC2b and Orai1, are involved in this process. However, it is still unclear whether 1,25-(OH)2D3 could stimulate calcium transport in the ruminant mammary gland. The present trials were conducted to study the effect of 1,25-(OH)2D3 supplementation and energy availability on the expression of genes and proteins related to calcium secretion in goat mammary epithelial cells. Methods An in vitro culture method for goat secreting mammary epithelial cells was successfully established. The cells were treated with different doses of 1,25-(OH)2D3 (0, 0.1, 1.0, 10.0 and 100.0 nmol/L) for calcium transport research, followed by a 3-bromopyruvate (3-BrPA, an inhibitor of glucose metabolism) treatment to determine its dependence on glucose availability. Cell proliferation ratios, glucose consumption and enzyme activities were measured with commercial kits, and real-time quantitative polymerase chain reaction (RT-qPCR), and western blots were used to determine the expression of genes and proteins associated with mammary calcium transport in dairy goats, respectively. Results 1,25-(OH)2D3 promoted cell proliferation and the expression of genes involved in calcium transport in a dose-dependent manner when the concentration did not exceed 10.0 nmol/L. In addition, 100.0 nmol/L 1,25-(OH)2D3 inhibited cell proliferation and the expression of associated genes compared with the 10.0 nmol/L treatment. The inhibition of hexokinase 2 (HK2), a rate-limiting enzyme in glucose metabolism, decreased the expression of PMCA1b and PMCA2b at the mRNA and protein levels as well as the transcription of Orai1, indicating that glucose availability was required for goat mammary calcium transport. The optimal concentration of 1,25-(OH)2D3 that facilitated calcium transport in this study was 10.0 nmol/L. Conclusions Supplementation with 1,25-(OH)2D3 influenced cell proliferation and regulated the expression of calcium transport modulators in a dose- and energy-dependent manner, thereby highlighting the role of 1,25-(OH)2D3 as an efficacious regulatory agent that produces calcium-enriched milk in ruminants when a suitable energy status was guaranteed.
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Affiliation(s)
- Feifei Sun
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi Peoples Republic of China
| | - Yangchun Cao
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi Peoples Republic of China
| | - Chao Yu
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi Peoples Republic of China
| | - Xiaoshi Wei
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi Peoples Republic of China
| | - Junhu Yao
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100 Shaanxi Peoples Republic of China
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Kim W, Takyar FM, Swan K, Jeong J, VanHouten J, Sullivan C, Dann P, Yu H, Fiaschi-Taesch N, Chang W, Wysolmerski J. Calcium-Sensing Receptor Promotes Breast Cancer by Stimulating Intracrine Actions of Parathyroid Hormone-Related Protein. Cancer Res 2016; 76:5348-60. [PMID: 27450451 DOI: 10.1158/0008-5472.can-15-2614] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 06/17/2016] [Indexed: 12/21/2022]
Abstract
Parathyroid hormone-related protein (PTHrP) contributes to the development and metastatic progression of breast cancer by promoting hypercalcemia, tumor growth, and osteolytic bone metastases, but it is not known how PTHrP is upregulated in breast tumors. Here we report a central role in this process for the calcium-sensing receptor, CaSR, which enables cellular responses to changes in extracellular calcium, through studies of CaSR-PTHrP interactions in the MMTV-PymT transgenic mouse model of breast cancer and in human breast cancer cells. CaSR activation stimulated PTHrP production by breast cancer cells in vitro and in vivo Tissue-specific disruption of the casr gene in mammary epithelial cells in MMTV-PymT mice reduced tumor PTHrP expression and inhibited tumor cell proliferation and tumor outgrowth. CaSR signaling promoted the proliferation of human breast cancer cell lines and tumor cells cultured from MMTV-PyMT mice. Further, CaSR activation inhibited cell death triggered by high extracellular concentrations of calcium. The actions of the CaSR appeared to be mediated by nuclear actions of PTHrP that decreased p27(kip1) levels and prevented nuclear accumulation of the proapoptotic factor apoptosis inducing factor. Taken together, our findings suggest that CaSR-PTHrP interactions might be a promising target for the development of therapeutic agents to limit tumor cell growth in bone metastases and in other microenvironments in which elevated calcium and/or PTHrP levels contribute to breast cancer progression. Cancer Res; 76(18); 5348-60. ©2016 AACR.
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Affiliation(s)
- Wonnam Kim
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Farzin M Takyar
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Karena Swan
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Jaekwang Jeong
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Joshua VanHouten
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Catherine Sullivan
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Pamela Dann
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut
| | - Herbert Yu
- Cancer Epidemiology Program, University of Hawaii Cancer Center, University of Hawaii School of Medicine, Honolulu, Hawaii
| | - Nathalie Fiaschi-Taesch
- Section of Endocrinology, Diabetes and Bone Disease, Department of Medicine, Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Wenhan Chang
- Endocrine Unit, San Francisco and Veteran Affairs Medical Center, University of California, San Francisco, California
| | - John Wysolmerski
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven Connecticut.
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Martin TJ. Parathyroid Hormone-Related Protein, Its Regulation of Cartilage and Bone Development, and Role in Treating Bone Diseases. Physiol Rev 2016; 96:831-71. [DOI: 10.1152/physrev.00031.2015] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although parathyroid hormone-related protein (PTHrP) was discovered as a cancer-derived hormone, it has been revealed as an important paracrine/autocrine regulator in many tissues, where its effects are context dependent. Thus its location and action in the vasculature explained decades-long observations that injection of PTH into animals rapidly lowered blood pressure by producing vasodilatation. Its roles have been specified in development and maturity in cartilage and bone as a crucial regulator of endochondral bone formation and bone remodeling, respectively. Although it shares actions with parathyroid hormone (PTH) through the use of their common receptor, PTHR1, PTHrP has other actions mediated by regions within the molecule beyond the amino-terminal sequence that resembles PTH, including the ability to promote placental transfer of calcium from mother to fetus. A striking feature of the physiology of PTHrP is that it possesses structural features that equip it to be transported in and out of the nucleus, and makes use of a specific nuclear import mechanism to do so. Evidence from mouse genetic experiments shows that PTHrP generated locally in bone is essential for normal bone remodeling. Whereas the main physiological function of PTH is the hormonal regulation of calcium metabolism, locally generated PTHrP is the important physiological mediator of bone remodeling postnatally. Thus the use of intermittent injection of PTH as an anabolic therapy for bone appears to be a pharmacological application of the physiological function of PTHrP. There is much current interest in the possibility of developing PTHrP analogs that might enhance the therapeutic anabolic effects.
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Affiliation(s)
- T. John Martin
- St Vincent's Institute of Medical Research, Department of Medicine, University of Melbourne, St Vincent's Hospital, Melbourne, Australia
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Kovacs CS. Maternal Mineral and Bone Metabolism During Pregnancy, Lactation, and Post-Weaning Recovery. Physiol Rev 2016; 96:449-547. [PMID: 26887676 DOI: 10.1152/physrev.00027.2015] [Citation(s) in RCA: 251] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During pregnancy and lactation, female physiology adapts to meet the added nutritional demands of fetuses and neonates. An average full-term fetus contains ∼30 g calcium, 20 g phosphorus, and 0.8 g magnesium. About 80% of mineral is accreted during the third trimester; calcium transfers at 300-350 mg/day during the final 6 wk. The neonate requires 200 mg calcium daily from milk during the first 6 mo, and 120 mg calcium from milk during the second 6 mo (additional calcium comes from solid foods). Calcium transfers can be more than double and triple these values, respectively, in women who nurse twins and triplets. About 25% of dietary calcium is normally absorbed in healthy adults. Average maternal calcium intakes in American and Canadian women are insufficient to meet the fetal and neonatal calcium requirements if normal efficiency of intestinal calcium absorption is relied upon. However, several adaptations are invoked to meet the fetal and neonatal demands for mineral without requiring increased intakes by the mother. During pregnancy the efficiency of intestinal calcium absorption doubles, whereas during lactation the maternal skeleton is resorbed to provide calcium for milk. This review addresses our current knowledge regarding maternal adaptations in mineral and skeletal homeostasis that occur during pregnancy, lactation, and post-weaning recovery. Also considered are the impacts that these adaptations have on biochemical and hormonal parameters of mineral homeostasis, the consequences for long-term skeletal health, and the presentation and management of disorders of mineral and bone metabolism.
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Affiliation(s)
- Christopher S Kovacs
- Faculty of Medicine-Endocrinology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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The calcium-sensing receptor and the hallmarks of cancer. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1398-407. [DOI: 10.1016/j.bbamcr.2015.11.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 02/07/2023]
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Ardeshirpour L, Dumitru C, Dann P, Sterpka J, VanHouten J, Kim W, Kostenuik P, Wysolmerski J. OPG Treatment Prevents Bone Loss During Lactation But Does Not Affect Milk Production or Maternal Calcium Metabolism. Endocrinology 2015; 156:2762-73. [PMID: 25961842 PMCID: PMC4511126 DOI: 10.1210/en.2015-1232] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Lactation is associated with increased bone turnover and rapid bone loss, which liberates skeletal calcium used for milk production. Previous studies suggested that an increase in the skeletal expression of receptor activator of nuclear factor kappa-light-chain-enhancer of activated B cells ligand (RANKL) coupled with a decrease in osteoprotegerin (OPG) levels likely triggered bone loss during lactation. In this study, we treated lactating mice with recombinant OPG to determine whether bone loss during lactation was dependent on RANKL signaling and whether resorption of the maternal skeleton was required to support milk production. OPG treatment lowered bone resorption rates and completely prevented bone loss during lactation but, surprisingly, did not decrease osteoclast numbers. In contrast, OPG was quite effective at lowering osteoblast numbers and inhibiting bone formation in lactating mice. Furthermore, treatment with OPG during lactation prevented the usual anabolic response associated with reversal of lactational bone loss after weaning. Preventing bone loss had no appreciable effect on milk production, milk calcium levels, or maternal calcium homeostasis when mice were on a standard diet. However, when dietary calcium was restricted, treatment with OPG caused maternal hypocalcemia, maternal death, and decreased milk production. These studies demonstrate that RANKL signaling is a requirement for bone loss during lactation, and suggest that osteoclast activity may be required to increase osteoblast numbers during lactation in preparation for the recovery of bone mass after weaning. These data also demonstrate that maternal bone loss is not absolutely required to supply calcium for milk production unless dietary calcium intake is inadequate.
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Affiliation(s)
- Laleh Ardeshirpour
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - Cristina Dumitru
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - Pamela Dann
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - John Sterpka
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - Joshua VanHouten
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - Wonnam Kim
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - Paul Kostenuik
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
| | - John Wysolmerski
- Section of Endocrinology (L.A.), Department of Pediatrics, and Section of Endocrinology and Metabolism (C.D., P.D., J.S., J.V., W.K., J.W.), Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06520; and Department of Metabolic Disorders (P.K.), Amgen, Inc, Thousand Oaks, California 91320
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Abstract
In addition to its prominent role in the parathyroid gland, the calcium-sensing receptor (CaSR) is expressed in various tissues, including the kidney. This article reviews current data on the calcium-sensing properties of the kidney, the localization of the CaSR protein along the nephron, and its function in calcium homeostasis and in hypercalciuria.
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Affiliation(s)
- Hakan R. Toka
- Division of Nephrology and Hypertension, Eastern Virginia Medical School, Norfolk, Virginia
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachussetts; and
| | - Martin R. Pollak
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachussetts; and
| | - Pascal Houillier
- Université Paris-Descartes, Sorbonne Paris-Cité, Centre de Recherche des Cordeliers, INSERM UMRS 1138, Service de Physiologie, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France
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29
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Abstract
The nourishment of neonates by nursing is the defining characteristic of mammals. However, despite considerable research into the neural control of lactation, an understanding of the signaling mechanisms underlying the production and expulsion of milk by mammary epithelial cells during lactation remains largely unknown. Here we demonstrate that a store-operated Ca(2+) channel subunit, Orai1, is required for both optimal Ca(2+) transport into milk and for milk ejection. Using a novel, 3D imaging strategy, we visualized live oxytocin-induced alveolar unit contractions in the mammary gland, and we demonstrated that in this model milk is ejected by way of pulsatile contractions of these alveolar units. In mammary glands of Orai1 knockout mice, these contractions are infrequent and poorly coordinated. We reveal that oxytocin also induces a large transient release of stored Ca(2+) in mammary myoepithelial cells followed by slow, irregular Ca(2+) oscillations. These oscillations, and not the initial Ca(2+) transient, are mediated exclusively by Orai1 and are absolutely required for milk ejection and pup survival, an observation that redefines the signaling processes responsible for milk ejection. These findings clearly demonstrate that Ca(2+) is not just a substrate for nutritional enrichment in mammals but is also a master regulator of the spatiotemporal signaling events underpinning mammary alveolar unit contraction. Orai1-dependent Ca(2+) oscillations may represent a conserved language in myoepithelial cells of other secretory epithelia, such as sweat glands, potentially shedding light on other Orai1 channelopathies, including anhidrosis (an inability to sweat).
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The role of the calcium-sensing receptor in disorders of abnormal calcium handling and cardiovascular disease. Curr Opin Nephrol Hypertens 2015; 23:494-501. [PMID: 24992569 DOI: 10.1097/mnh.0000000000000042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW The calcium-sensing receptor (CaSR) has a central role in parathyroid gland function. Genetic alterations in CaSR are well known to cause inherited forms of abnormal calcium homeostasis. This review focuses on studies investigating the role of CaSR in common disorders of abnormal calcium handling and in cardiovascular calcification. RECENT FINDINGS Genetic population studies tested the association of common allelic CASR variants with serum and urine calcium levels, kidney stone disease, primary hyperparathyroidism and bone mineral density. The results of these association studies suggested either minor or no effects of CASR variants in these phenotypes. Decreased expression of CaSR was associated with the etiology of cardiovascular calcification in individuals with advanced chronic kidney disease. SUMMARY Ionized calcium plays a central role in the physiology of many organ systems and disease states, but the roles of CaSR other than as illustrated by Mendelian forms of CaSR dysfunction remain unclear. The contributions of CaSR to bone mineral homeostasis, vascular calcification and other forms of cardiovascular disease need further investigation.
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Abstract
PURPOSE OF REVIEW Variations in extracellular calcium level have a large impact on kidney function. Most of the effects seen are attributed to the calcium-sensing receptor (CaSR), a widely expressed G-protein-coupled cell surface protein with an important function in bone mineral homeostasis. The purpose of this review is to recapitulate the novel functional aspects of CaSR. RECENT FINDINGS Results from mouse models demonstrate important functions for CaSR in various tissues. In the kidney, the main role of CaSR is the regulation of calcium reabsorption in the thick ascending limb, independently of its role on parathyroid hormone secretion. CaSR modulates claudin 14, the gatekeeper of paracellular ion transport in the thick ascending limb that is associated with urinary calcium excretion. One intracellular signaling pathway by which CaSR alters tight junction permeability is the calcineurin-NFAT1c-microRNA-claudin14 axis. SUMMARY The main function of CaSR in the kidney is the regulation of calcium excretion in the thick ascending limb, independently of parathyroid hormone. CaSR modulates paracellular cation transport by altering expression of the tight junction protein claudin 14. Still more work is needed to fully understand all functions of CaSR in the kidney. Alternative pathways of calcium 'sensing' in the kidney need to be investigated.
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Affiliation(s)
- Hakan R Toka
- aDivision of Nephrology, Beth Israel Deaconess Medical Center bDivision of Nephrology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Kovacs CS. Bone development and mineral homeostasis in the fetus and neonate: roles of the calciotropic and phosphotropic hormones. Physiol Rev 2014; 94:1143-218. [PMID: 25287862 DOI: 10.1152/physrev.00014.2014] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mineral and bone metabolism are regulated differently in utero compared with the adult. The fetal kidneys, intestines, and skeleton are not dominant sources of mineral supply for the fetus. Instead, the placenta meets the fetal need for mineral by actively transporting calcium, phosphorus, and magnesium from the maternal circulation. These minerals are maintained in the fetal circulation at higher concentrations than in the mother and normal adult, and such high levels appear necessary for the developing skeleton to accrete a normal amount of mineral by term. Parathyroid hormone (PTH) and calcitriol circulate at low concentrations in the fetal circulation. Fetal bone development and the regulation of serum minerals are critically dependent on PTH and PTH-related protein, but not vitamin D/calcitriol, fibroblast growth factor-23, calcitonin, or the sex steroids. After birth, the serum calcium falls and phosphorus rises before gradually reaching adult values over the subsequent 24-48 h. The intestines are the main source of mineral for the neonate, while the kidneys reabsorb mineral, and bone turnover contributes mineral to the circulation. This switch in the regulation of mineral homeostasis is triggered by loss of the placenta and a postnatal fall in serum calcium, and is followed in sequence by a rise in PTH and then an increase in calcitriol. Intestinal calcium absorption is initially a passive process facilitated by lactose, but later becomes active and calcitriol-dependent. However, calcitriol's role can be bypassed by increasing the calcium content of the diet, or by parenteral administration of calcium.
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Affiliation(s)
- Christopher S Kovacs
- Faculty of Medicine-Endocrinology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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Leach K, Sexton PM, Christopoulos A, Conigrave AD. Engendering biased signalling from the calcium-sensing receptor for the pharmacotherapy of diverse disorders. Br J Pharmacol 2014; 171:1142-55. [PMID: 24111791 DOI: 10.1111/bph.12420] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 12/14/2022] Open
Abstract
The human calcium-sensing receptor (CaSR) is widely expressed in the body, where its activity is regulated by multiple orthosteric and endogenous allosteric ligands. Each ligand stabilizes a unique subset of conformational states, which enables the CaSR to couple to distinct intracellular signalling pathways depending on the extracellular milieu in which it is bathed. Differential signalling arising from distinct receptor conformations favoured by each ligand is referred to as biased signalling. The outcome of CaSR activation also depends on the cell type in which it is expressed. Thus, the same ligand may activate diverse pathways in distinct cell types. Given that the CaSR is implicated in numerous physiological and pathophysiological processes, it is an ideal target for biased ligands that could be rationally designed to selectively regulate desired signalling pathways in preferred cell types.
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Affiliation(s)
- K Leach
- Pharmaceutical Sciences, Monash University, Melbourne, Vic., Australia
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Peripheral serotonin regulates maternal calcium trafficking in mammary epithelial cells during lactation in mice. PLoS One 2014; 9:e110190. [PMID: 25299122 PMCID: PMC4192539 DOI: 10.1371/journal.pone.0110190] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/08/2014] [Indexed: 12/26/2022] Open
Abstract
Lactation is characterized by massive transcellular flux of calcium, from the basolateral side of the mammary alveolar epithelium (blood) into the ductal lumen (milk). Regulation of calcium transport during lactation is critical for maternal and neonatal health. The monoamine serotonin (5-HT) is synthesized by the mammary gland and functions as a homeostatic regulation of lactation. Genetic ablation of tryptophan hydroxylase 1 (Tph1), which encodes the rate-limiting enzyme in non-neuronal serotonin synthesis, causes a deficiency in circulating serotonin. As a consequence maternal calcium concentrations decrease, mammary epithelial cell morphology is altered, and cell proliferation is decreased during lactation. Here we demonstrate that serotonin deficiency decreases the expression and disrupts the normal localization of calcium transporters located in the apical (PMCA2) and basolateral (CaSR, ORAI-1) membranes of the lactating mammary gland. In addition, serotonin deficiency decreases the mRNA expression of calcium transporters located in intracellular compartments (SERCA2, SPCA1 and 2). Mammary expression of serotonin receptor isoform 2b and its downstream pathways (PLCβ3, PKC and MAP-ERK1/2) are also decreased by serotonin deficiency, which might explain the numerous phenotypic alterations described above. In most cases, addition of exogenous 5-hydroxy-L-tryptophan to the Tph1 deficient mice rescued the phenotype. Our data supports the hypothesis that serotonin is necessary for proper mammary gland structure and function, to regulate blood and mammary epithelial cell transport of calcium during lactation. These findings can be applicable to the treatment of lactation-induced hypocalcemia in dairy cows and can have profound implications in humans, given the wide-spread use of selective serotonin reuptake inhibitors as antidepressants during pregnancy and lactation.
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Laporta J, Keil KP, Weaver SR, Cronick CM, Prichard AP, Crenshaw TD, Heyne GW, Vezina CM, Lipinski RJ, Hernandez LL. Serotonin regulates calcium homeostasis in lactation by epigenetic activation of hedgehog signaling. Mol Endocrinol 2014; 28:1866-74. [PMID: 25192038 DOI: 10.1210/me.2014-1204] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Calcium homeostasis during lactation is critical for maternal and neonatal health. We previously showed that nonneuronal/peripheral serotonin [5-hydroxytryptamine (5-HT)] causes the lactating mammary gland to synthesize and secrete PTHrP in an acute fashion. Here, using a mouse model, we found that genetic inactivation of tryptophan hydroxylase 1 (Tph1), which catalyzes the rate-limiting step in peripheral 5-HT synthesis, reduced circulating and mammary PTHrP expression, osteoclast activity, and maternal circulating calcium concentrations during the transition from pregnancy to lactation. Tph1 inactivation also reduced sonic hedgehog signaling in the mammary gland during lactation. Each of these deficiencies was rescued by daily injections of 5-hydroxy-L-tryptophan (an immediate precursor of 5-HT) to Tph1-deficient dams. We used immortalized mouse embryonic fibroblasts to demonstrate that 5-HT induces PTHrP through a sonic hedgehog-dependent signal transduction mechanism. We also found that 5-HT altered DNA methylation of the Shh gene locus, leading to transcriptional initiation at an alternate start site and formation of a variant transcript in mouse embryonic fibroblasts in vitro and in mammary tissue in vivo. These results support a new paradigm of 5-HT-mediated Shh regulation involving DNA methylation remodeling and promoter switching. In addition to having immediate implications for lactation biology, identification and characterization of a novel functional regulatory relationship between nonneuronal 5-HT, hedgehog signaling, and PTHrP offers new avenues for the study of these important factors in development and disease.
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Affiliation(s)
- Jimena Laporta
- Departments of Dairy Science (J.L., S.R.W., C.M.C., A.P.P., L.L.H.), Comparative Biosciences (K.P.K., G.W.H., C.M.V., R.J.L.), and Animal Science (T.D.C.), University of Wisconsin-Madison, Madison, Wisconsin 53706
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Kovacs CS. The Role of PTHrP in Regulating Mineral Metabolism During Pregnancy, Lactation, and Fetal/Neonatal Development. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9157-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Nordholm A, Rix M, Olgaard K, Lewin E. Parathyroid hormone-related peptide plasma concentrations in patients on hemodialysis. Scandinavian Journal of Clinical and Laboratory Investigation 2014; 74:206-12. [DOI: 10.3109/00365513.2013.876656] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Ross DGF, Smart CE, Azimi I, Roberts-Thomson SJ, Monteith GR. Assessment of ORAI1-mediated basal calcium influx in mammary epithelial cells. BMC Cell Biol 2013; 14:57. [PMID: 24359162 PMCID: PMC3878224 DOI: 10.1186/1471-2121-14-57] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 12/09/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The entry of calcium ions into mammary gland epithelial cells is one of the least well-understood processes in the transport of calcium into milk during lactation. The store-operated calcium entry channel ORAI1, has been suggested as a potential mechanism for the entry of Ca(2+) into mammary gland epithelial cells from the maternal blood supply during lactation. The down regulation of the canonical ORAI1 activator STIM1 during lactation suggests that other known ORAI activators such as STIM2 and SPCA2 may be important during lactation. RESULTS Differentiation of HC11 mammary gland epithelial cells was associated with enhanced basal Ca(2+) influx. Silencing of Orai1 abolished this enhancement of Ca(2+) influx. Stim2 had a modest effect on Ca(2+) influx in this in vitro model of lactation, whereas Stim1 and Spca2 silencing had no effect. Despite pronounced increases in Spca2 mRNA during lactation there was no change in the generation of the alternative splice product generated by Mist1, which increases during lactation. CONCLUSIONS These studies support the hypothesis that lactation is associated with a remodelling of Ca(2+) influx and this is associated with enhancement of basal Ca(2+) influx. This enhanced Ca(2+) influx appears to occur through the calcium channel Orai1.
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Affiliation(s)
- Diana GF Ross
- School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, QLD, Australia
| | - Chanel E Smart
- University of Queensland Centre for Clinical Research (UQCCR), Building 71/918 Royal Brisbane and Women’s Hospital, Herston, QLD 4029, Australia
| | - Iman Azimi
- School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, QLD, Australia
| | - Sarah J Roberts-Thomson
- School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, QLD, Australia
| | - Gregory R Monteith
- School of Pharmacy, The University of Queensland, Pharmacy Australia Centre of Excellence, 20 Cornwall St, Woolloongabba, QLD, Australia
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Cross BM, Breitwieser GE, Reinhardt TA, Rao R. Cellular calcium dynamics in lactation and breast cancer: from physiology to pathology. Am J Physiol Cell Physiol 2013; 306:C515-26. [PMID: 24225884 DOI: 10.1152/ajpcell.00330.2013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Breast cancer is the second leading cause of cancer mortality in women, estimated at nearly 40,000 deaths and more than 230,000 new cases diagnosed in the U.S. this year alone. One of the defining characteristics of breast cancer is the radiographic presence of microcalcifications. These palpable mineral precipitates are commonly found in the breast after formation of a tumor. Since free Ca(2+) plays a crucial role as a second messenger inside cells, we hypothesize that these chelated precipitates may be a result of dysregulated Ca(2+) secretion associated with tumorigenesis. Transient and sustained elevations of intracellular Ca(2+) regulate cell proliferation, apoptosis and cell migration, and offer numerous therapeutic possibilities in controlling tumor growth and metastasis. During lactation, a developmentally determined program of gene expression controls the massive transcellular mobilization of Ca(2+) from the blood into milk by the coordinated action of calcium transporters, including pumps, channels, sensors and buffers, in a functional module that we term CALTRANS. Here we assess the evidence implicating genes that regulate free and buffered Ca(2+) in normal breast epithelium and cancer cells and discuss mechanisms that are likely to contribute to the pathological characteristics of breast cancer.
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Affiliation(s)
- Brandie M Cross
- Department of Physiology, The Johns Hopkins University, Baltimore, Maryland
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