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Dong B, Mehran S, Yang Y, Jing H, Liang L, Guo X, Zhang Q. Effect of leptin on the growth and expression of STAT3 in yak mammary epithelial cells. Vet World 2022; 15:2141-2150. [DOI: 10.14202/vetworld.2022.2141-2150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Background and Aim: Leptin (LEP) is an autocrine and paracrine factor produced by the fat pad and acinar epithelial cells of the breast. This study aimed to investigate the effects of LEP on yak mammary epithelial cells (YMECs) and the expression of STAT3. In addition, we evaluated the possible effects of prolactin (PRL) on the function of LEP.
Materials and Methods: The YMECs were treated with 0, 50, 100, 200, 400, and 800 ng/mL LEP for 48 h in the absence of PRL and the presence of 500 ng/mL PRL. The growth activity of YMECs was measured using the cell counting kit-8 assay. The changes in the lactation signaling pathway-related factor STAT3 were detected at the mRNA, protein, and protein phosphorylation levels using the reverse transcriptase-quantitative polymerase chain reaction and Western blotting. To explore whether LEP affects the activation of STAT3 through JAK2/JAK3 in YMECs, the JAK2/3 signaling pathway inhibitor AG490 was used at a fixed concentration of LEP.
Results: Each concentration of LEP significantly promoted the expression of STAT3 mRNA (p < 0.05) in YMECs in the presence of PRL. In the absence of PRL, all concentrations of LEP were found to inhibit the expression of the STAT3 protein (p < 0.05). The expression of the STAT3 protein in YMECs was found to first increase followed by a decrease with an increase in the concentration of LEP. In addition, the phosphorylation level of STAT3 increased in all groups, except the 100 ng/mL concentration group. The STAT3 phosphorylation trend and protein expression were different, such that the level of protein phosphorylation was higher than that of the STAT3 protein (p < 0.05). The addition of AG490 reduced the expression of the STAT3 mRNA, STAT3 protein, and STAT3 phosphorylation in the LEP and LEP + PRL groups.
Conclusion: Altogether, the results indicated that different concentrations of LEP exerted varying effects on the growth of YMECs and the expression of STAT3, and the activity of STAT3 was primarily activated by JAK2. The addition of LEP can effectively inhibit the downregulation of the JAK2/STAT3 signal pathway by AG490, mitigate its inhibitory effect on the proliferation of YMECs, and reduce apoptosis. We believe that these findings will provide a theoretical and experimental basis for future research in this field.
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Affiliation(s)
- Baoxia Dong
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
| | - Sidra Mehran
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
| | - Yuying Yang
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
| | - Haixia Jing
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
| | - Lin Liang
- Department of Biotechnology, Kunlun College, Qinghai University, Xining, China
| | - Xiaoyu Guo
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
| | - Qinwen Zhang
- Department of Animal Medicine, College of Agriculture and Animal Husbandry, Qinghai University, Xining, China
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Thakkar N, Shin YB, Sung HK. Nutritional Regulation of Mammary Tumor Microenvironment. Front Cell Dev Biol 2022; 10:803280. [PMID: 35186923 PMCID: PMC8847692 DOI: 10.3389/fcell.2022.803280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
The mammary gland is a heterogeneous organ comprising of immune cells, surrounding adipose stromal cells, vascular cells, mammary epithelial, and cancer stem cells. In response to nutritional stimuli, dynamic interactions amongst these cell populations can be modulated, consequently leading to an alteration of the glandular function, physiology, and ultimately disease pathogenesis. For example, obesity, a chronic over-nutritional condition, is known to disrupt homeostasis within the mammary gland and increase risk of breast cancer development. In contrast, emerging evidence has demonstrated that fasting or caloric restriction can negatively impact mammary tumorigenesis. However, how fasting induces phenotypic and functional population differences in the mammary microenvironment is not well understood. In this review, we will provide a detailed overview on the effect of nutritional conditions (i.e., overnutrition or fasting) on the mammary gland microenvironment and its impact on mammary tumor progression.
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Affiliation(s)
- Nikita Thakkar
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Ye Bin Shin
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Hoon-Ki Sung
- Translational Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- *Correspondence: Hoon-Ki Sung,
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Slepicka PF, Somasundara AVH, Dos Santos CO. The molecular basis of mammary gland development and epithelial differentiation. Semin Cell Dev Biol 2021; 114:93-112. [PMID: 33082117 PMCID: PMC8052380 DOI: 10.1016/j.semcdb.2020.09.014] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023]
Abstract
Our understanding of the molecular events underpinning the development of mammalian organ systems has been increasing rapidly in recent years. With the advent of new and improved next-generation sequencing methods, we are now able to dig deeper than ever before into the genomic and epigenomic events that play critical roles in determining the fates of stem and progenitor cells during the development of an embryo into an adult. In this review, we detail and discuss the genes and pathways that are involved in mammary gland development, from embryogenesis, through maturation into an adult gland, to the role of pregnancy signals in directing the terminal maturation of the mammary gland into a milk producing organ that can nurture the offspring. We also provide an overview of the latest research in the single-cell genomics of mammary gland development, which may help us to understand the lineage commitment of mammary stem cells (MaSCs) into luminal or basal epithelial cells that constitute the mammary gland. Finally, we summarize the use of 3D organoid cultures as a model system to study the molecular events during mammary gland development. Our increased investigation of the molecular requirements for normal mammary gland development will advance the discovery of targets to predict breast cancer risk and the development of new breast cancer therapies.
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Affiliation(s)
- Priscila Ferreira Slepicka
- Stem Cell Transplantation and Regenerative Medicine, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | | | - Camila O Dos Santos
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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Abstract
Leptin is a hormone that plays a major role as mediator of long-term regulation of energy balance, suppressing food intake, and stimulating weight loss. More recently, important physiological roles other than controlling appetite and energy expenditure have been suggested for leptin, including neuroendocrine, reparative, reproductive, and immune functions. These emerging peripheral roles let hypothesize that leptin can modulate also cancer progression. Indeed, many studies have demonstrated that elevated chronic serum concentrations of leptin, frequently seen in obese subjects, represent a stimulatory signal for tumor growth. Current knowledge indicates that also different non-tumoral cells resident in tumor microenvironment may respond to leptin creating a favorable soil for cancer cells. In addition, leptin is produced also within the tumor microenvironment creating the possibility for paracrine and autocrine action. In this review, we describe the main mechanisms that regulate peripheral leptin availability and how leptin can shape tumor microenvironment.
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Leptin and Leptin Resistance in the Pathogenesis of Obstructive Sleep Apnea: A Possible Link to Oxidative Stress and Cardiovascular Complications. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5137947. [PMID: 29675134 PMCID: PMC5841044 DOI: 10.1155/2018/5137947] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/05/2018] [Accepted: 01/23/2018] [Indexed: 12/17/2022]
Abstract
Obesity-related sleep breathing disorders such as obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS) cause intermittent hypoxia (IH) during sleep, a powerful trigger of oxidative stress. Obesity also leads to dramatic increases in circulating levels of leptin, a hormone produced in adipose tissue. Leptin acts in the hypothalamus to suppress food intake and increase metabolic rate. However, obese individuals are resistant to metabolic effects of leptin. Leptin also activates the sympathetic nervous system without any evidence of resistance, possibly because these effects occur peripherally without a need to penetrate the blood-brain barrier. IH is a potent stimulator of leptin expression and release from adipose tissue. Hyperleptinemia and leptin resistance may upregulate generation of reactive oxygen species, increasing oxidative stress and promoting inflammation. The current review summarizes recent data on a possible link between leptin and oxidative stress in the pathogenesis of sleep breathing disorders.
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Poljaroen J, Tinikul Y, Tinikul R, Anurucpreeda P, Sobhon P. Leptin-like immunoreactivity in the central nervous system, digestive organs, and gonads of the giant freshwater prawn, Macrobrachium rosenbergii. Acta Histochem 2017. [PMID: 28624121 DOI: 10.1016/j.acthis.2017.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Leptin, a highly conserved adipocyte-derived hormone, plays important roles in a variety of physiological processes, including the control of fat storage and metabolic status which are linked to food intake, energy homeostasis, and reproduction in all vertebrates. In the present study, we hypothesize that leptin is also present in various organs of the fresh water prawns, Macrobrachium rosenbergii. The existence and distribution of a leptin-like peptide in prawn tissues were verified by using Western blotting (WB) and immunohistochemical detection (ID) using primary antibody against human leptin. With WB, a leptin-like peptide, having a molecular weight of 15kDa, was detected in the brain, thoracic ganglia, abdominal ganglia, parts of the gastro-intestinal tract, hepatopancreas, adipocytes and gonads. By ID, leptin immunoreactivity (leptin-ir) was detected in the brain, thoracic ganglia and intersegmental commissural nerve fibers of abdominal ganglia. In the gastrointestinal tract, there was intense leptin-ir in the apical part of the epithelial cells of the cardiac and pyloric parts of the stomach. In the midgut and hindgut, the leptin-ir was detected in epithelial cells and basal cells located near the basal lamina of the epithelium. In addition, there was leptin-ir in the Restzellen cells in the hepatopancreas which produce digestive enzymes. In the ovary, the strong intensity of a leptin-ir was detected in the cytoplasm of middle to late stage oocytes, whereas no positive staining was detected in follicular cells. An intense leptin-ir was detected in spermatocytes and sustentacular cells in the seminiferous tubules in the testes of small and orange claw males. Taken together, the detection of the leptin-ir in several organs implicates the existence of a leptin-like peptide in various organs of the freshwater prawn; and like in vertebrates this peptide may be an important hormonal factor in controlling feeding and reproductive process.
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7
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Hou X, Lin L, Xing W, Yang Y, Duan X, Li Q, Gao X, Lin Y. Spleen tyrosine kinase regulates mammary epithelial cell proliferation in mammary glands of dairy cows. J Dairy Sci 2016; 99:3858-3868. [PMID: 26947307 DOI: 10.3168/jds.2015-10118] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 01/17/2016] [Indexed: 11/19/2022]
Abstract
Spleen tyrosine kinase (SYK) is a nonreceptor tyrosine kinase that has been considered a hematopoietic cell-specific signal transducer involved in cell proliferation and differentiation. However, the role of SYK in normal mammary gland is still poorly understood. Here we show that SYK is expressed in mammary glands of dairy cows. Expression of SYK was higher in dry period mammary tissues than in lactating mammary tissues. Knockdown and overexpression of SYK affected dairy cow mammary epithelial cell proliferation as well as the expression of signal molecules involved in proliferation, including protein kinase B (PKB, also known as AKT1), p42/44 mitogen-activated protein kinase (MAPK), and signal transducer and activator of transcription 5 (STAT5). Dual-luciferase reporter assay showed that SYK increased the transcriptional activity of the AKT1 promoter, and cis-elements within the AKT1 promoter region from -439 to -84 bp mediated this regulation. These results suggest that SYK affects mammary epithelial cell proliferation by activating AKT1 at the transcriptional level in mammary glands of dairy cows, which is important for the mammary remodeling process in dry cows as well as for increasing persistency of lactation in lactating cows.
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Affiliation(s)
- Xiaoming Hou
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Lin Lin
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Weinan Xing
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Yang Yang
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Xiaoyu Duan
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Qingzhang Li
- College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
| | - Xuejun Gao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
| | - Ye Lin
- College of Life Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China.
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8
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Bostanci Z, Mack RP, Lee S, Soybel DI, Kelleher SL. Paradoxical zinc toxicity and oxidative stress in the mammary gland during marginal dietary zinc deficiency. Reprod Toxicol 2014; 54:84-92. [PMID: 25088245 DOI: 10.1016/j.reprotox.2014.07.076] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 07/07/2014] [Accepted: 07/22/2014] [Indexed: 01/06/2023]
Abstract
Zinc (Zn) regulates numerous cellular functions. Zn deficiency is common in females; ∼80% of women and 40% of adolescent girls consume inadequate Zn. Zn deficiency enhances oxidative stress, inflammation and DNA damage. Oxidative stress and inflammation is associated with breast disease. We hypothesized that Zn deficiency increases oxidative stress in the mammary gland, altering the microenvironment and architecture. Zn accumulated in the mammary glands of Zn deficient mice and this was associated with macrophage infiltration, enhanced oxidative stress and over-expression of estrogen receptor α. Ductal and stromal hypercellularity was associated with aberrant collagen deposition and disorganized e-cadherin. Importantly, these microenvironmental alterations were associated with substantial impairments in ductal expansion and mammary gland development. This is the first study to show that marginal Zn deficiency creates a toxic microenvironment in the mammary gland impairing breast development. These changes are consistent with hallmarks of potential increased risk for breast disease and cancer.
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Affiliation(s)
- Zeynep Bostanci
- Department of Nutritional Sciences, The Pennsylvania State University, United States; Department of Surgery, Penn State Hershey College of Medicine, United States
| | - Ronald P Mack
- Department of Nutritional Sciences, The Pennsylvania State University, United States; Department of Kinesiology, The Pennsylvania State University, United States
| | - Sooyeon Lee
- Department of Nutritional Sciences, The Pennsylvania State University, United States; Interdisciplinary Graduate Program in Physiology, The Pennsylvania State University, United States
| | - David I Soybel
- Department of Nutritional Sciences, The Pennsylvania State University, United States; Department of Surgery, Penn State Hershey College of Medicine, United States; Department of Cell and Molecular Physiology, Penn State Hershey College of Medicine, United States
| | - Shannon L Kelleher
- Department of Nutritional Sciences, The Pennsylvania State University, United States; Interdisciplinary Graduate Program in Physiology, The Pennsylvania State University, United States; Department of Surgery, Penn State Hershey College of Medicine, United States; Department of Cell and Molecular Physiology, Penn State Hershey College of Medicine, United States.
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9
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Fornetti J, Martinson HA, Betts CB, Lyons TR, Jindal S, Guo Q, Coussens LM, Borges VF, Schedin P. Mammary gland involution as an immunotherapeutic target for postpartum breast cancer. J Mammary Gland Biol Neoplasia 2014; 19:213-28. [PMID: 24952477 PMCID: PMC4363120 DOI: 10.1007/s10911-014-9322-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 06/09/2014] [Indexed: 12/24/2022] Open
Abstract
Postpartum mammary gland involution has been identified as tumor-promotional and is proposed to contribute to the increased rates of metastasis and poor survival observed in postpartum breast cancer patients. In rodent models, the involuting mammary gland microenvironment is sufficient to induce enhanced tumor cell growth, local invasion, and metastasis. Postpartum involution shares many attributes with wound healing, including upregulation of genes involved in immune responsiveness and infiltration of tissue by immune cells. In rodent models, treatment with non-steroidal anti-inflammatory drugs (NSAIDs) ameliorates the tumor-promotional effects of involution, consistent with the immune milieu of the involuting gland contributing to tumor promotion. Currently, immunotherapy is being investigated as a means of breast cancer treatment with the purpose of identifying ways to enhance anti-tumor immune responses. Here we review evidence for postpartum mammary gland involution being a uniquely defined 'hot-spot' of pro-tumorigenic immune cell infiltration, and propose that immunotherapy should be explored for prevention and treatment of breast cancers that arise in this environment.
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Affiliation(s)
- Jaime Fornetti
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
- Program in Reproductive Sciences, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Holly A. Martinson
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
- Cancer Biology Program, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave, Aurora, CO 80045, USA
| | - Courtney B. Betts
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
- Cell Biology, Stem cells, and Development, 12801 E 17th Ave, Aurora, CO 80045, USA
| | - Traci R. Lyons
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
| | - Sonali Jindal
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
| | - Qiuchen Guo
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
- Cancer Biology Program, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave, Aurora, CO 80045, USA
| | - Lisa M. Coussens
- Department of Cell & Developmental Biology, Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Virginia F. Borges
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
| | - Pepper Schedin
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Young Women’s Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
- Program in Reproductive Sciences, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO 80045, USA
- Cancer Biology Program, University of Colorado Anschutz Medical Campus, 12801 E 17th Ave, Aurora, CO 80045, USA
- Cell Biology, Stem cells, and Development, 12801 E 17th Ave, Aurora, CO 80045, USA
- Department of Cell & Developmental Biology, Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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Hovey RC, Aimo L. Diverse and active roles for adipocytes during mammary gland growth and function. J Mammary Gland Biol Neoplasia 2010; 15:279-90. [PMID: 20717712 PMCID: PMC2941079 DOI: 10.1007/s10911-010-9187-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 08/06/2010] [Indexed: 12/18/2022] Open
Abstract
The mammary gland is unique in its requirement to develop in close association with a depot of adipose tissue that is commonly referred to as the mammary fat pad. As discussed throughout this issue, the mammary fat pad represents a complex stromal microenvironment that includes a variety of cell types. In this article we focus on adipocytes as local regulators of epithelial cell growth and their function during lactation. Several important considerations arise from such a discussion. There is a clear and close interrelationship between different stromal tissue types within the mammary fat pad and its adipocytes. Furthermore, these relationships are both stage- and species-dependent, although many questions remain unanswered regarding their roles in these different states. Several lines of evidence also suggest that adipocytes within the mammary fat pad may function differently from those in other fat depots. Finally, past and future technologies present a variety of opportunities to model these complexities in order to more precisely delineate the many potential functions of adipocytes within the mammary glands. A thorough understanding of the role for this cell type in the mammary glands could present numerous opportunities to modify both breast cancer risk and lactation performance.
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Affiliation(s)
- Russell C Hovey
- Department of Animal Science, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
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Thorn SR, Giesy SL, Myers MG, Boisclair YR. Mammary ductal growth is impaired in mice lacking leptin-dependent signal transducer and activator of transcription 3 signaling. Endocrinology 2010; 151:3985-95. [PMID: 20501669 PMCID: PMC3208358 DOI: 10.1210/en.2010-0029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mice lacking leptin (ob/ob) or its full-length receptor (db/db) are obese and reproductively incompetent. Fertility, pregnancy, and lactation are restored, respectively, in ob/ob mice treated with leptin through mating, d 6.5 post coitum, and pregnancy. Therefore, leptin signaling is needed for lactation, but the timing of its action and the affected mammary process remain unknown. To address this issue, we used s/s mice lacking only leptin-dependent signal transducer and activator of transcription (STAT)3 signaling. These mice share many features with db/db mice, including obesity, but differ by retaining sufficient activity of the hypothalamic-pituitary-ovarian axis to support reproduction. The s/s mammary epithelium was normal at 3 wk of age but failed to expand through the mammary fat pad (MFP) during the subsequent pubertal period. Ductal growth failure was not corrected by estrogen therapy and did not relate to inadequate IGF-I production by the MFP or to the need for epithelial or stromal leptin-STAT3 signaling. Ductal growth failure coincided with adipocyte hypertrophy and increased MFP production of leptin, TNFalpha, and IL6. These cytokines, however, were unable to inhibit the proliferation of a collection of mouse mammary epithelial cell lines. In conclusion, the very first step of postnatal mammary development fails in s/s mice despite sufficient estrogen IGF-I and an hypothalamic-pituitary-ovarian axis capable of supporting reproduction. This failure is not caused by mammary loss of leptin-dependent STAT3 signaling or by the development of inflammation. These data imply the existence of an unknown mechanism whereby leptin-dependent STAT3 signaling and obesity alter mammary ductal development.
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Affiliation(s)
- Stephanie R Thorn
- Department of Animal Science, Cornell University, Ithaca, New York 14853, USA
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Reproductive abnormalities in mice expressing omega-3 fatty acid desaturase in their mammary glands. Transgenic Res 2010; 20:283-92. [PMID: 20532624 PMCID: PMC3051059 DOI: 10.1007/s11248-010-9407-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 05/21/2010] [Indexed: 12/19/2022]
Abstract
The Caenorhabditis elegans n-3 fatty acid desaturase (Fat-1) acts on a range of 18- and 20-carbon n-6 fatty acid substrates. Transgenic female mice expressing the Fat-1 gene under transcriptional control of the goat β-casein promoter produce milk phospholipids having elevated levels of n-3 polyunsaturated fatty acids (PUFA). However, females from this line were also observed to have impaired reproductive performance characterized by a smaller litter size (2.7 ± 0.6 vs. 7.2 ± 0.7; P < 0.05) than wildtype controls. While there is a close association between PUFA metabolism, prostaglandin biosynthesis, and fertility; reproductive problems in these mice were unanticipated given that the Fat-1 transgene is primarily expressed in the lactating mammary gland. Using multiple approaches it was found that Fat-1 mice have normal ovulation and fertilization rates; however fewer embryos were present in the uterus prior to implantation. Small litter size was also found to be partly attributable to a high incidence of post-implantation fetal resorptions. Embryo transfer experiments revealed that embryos developing from oocytes derived from transgenic ovaries had an increased rate of post-implantation resorption, regardless of the uterine genotype. Ovary transplantation between Fat-1 and C57BL/6 wildtype females revealed that non-ovarian factors also contributed to the smaller litter size phenotype. Finally, surgical removal of the mammary glands from juvenile Fat-1 mice increased the subsequent number of implantation sites per female, but did not lessen the high rate of post-implantation resorptions. In conclusion, we herein report on a system where an exogenous transgene expressed predominately in the mammary gland detrimentally affects female reproduction, suggesting that in certain circumstances the mammary gland may function as an endocrine regulator of reproductive performance.
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13
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Abstract
Leptin is an autocrine and paracrine factor which affects the development and function of mammary gland. The purpose of this study was to investigate the presence and regulatory effect of leptin in Chinese Guan Zhong dairy goat mammary gland from the virgin state to involution. The protein expression and localization of leptin and its long form receptor (OB-Rb) were detected by western blot and a confocal laser scanning microscope. Explants were cultured to detect the impacts of leptin on mammary gland, western blot was used to research leptin signal transduction pathway in pregnancy, lactation and involution. Leptin and amounts of OB-Rb protein were high throughout the virgin stage and at the beginning of pregnancy, lower at mid-pregnancy and throughout lactation, then higher at involution. Immunofluorescence performed with the anti-leptin and anti-leptin receptor antibody showed labelling located in adipose, epithelial cells, or extracellular matrix at different stages. The localization of leptin and OB-Rb revealed that leptin induced the expression of OB-Rb specifically and controlled the development and physiological function of the mammary gland by binding to OB-Rb. Leptin stimulated the proliferation and differentiation of ductal epithelial cells in pregnancy by JAK-MAPK signal pathway, enhanced the amount of β-casein in cultured lactating mammary gland by JAK-STAT5 signal pathway, made the mammary duct disappear and induced apoptosis of mammary epithelial cells and mammary gland restitution by JAK-STAT3 signal pathway in involution. Overall, this study demonstrated the importance and complexity of leptin and OB-Rb during mammary gland development and provides a valuable resource for future research in this area.
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