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1.
Nat Commun ; 11(1): 5133, 2020 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-33046706

RESUMO

Cathepsin D (CTSD) is a lysosomal protease and a marker of poor prognosis in breast cancer. However, the cells responsible for this association and the function of CTSD in cancer are still incompletely understood. By using a conditional CTSD knockout mouse crossed to the transgenic MMTV-PyMT breast cancer model we demonstrate that CTSD deficiency in the mammary epithelium, but not in myeloid cells, blocked tumor development in a cell-autonomous manner. We show that lack of CTSD impaired mechanistic Target of Rapamycin Complex 1 (mTORC1) signaling and induced reversible cellular quiescence. In line, CTSD-deficient tumors started to grow with a two-month delay and quiescent Ctsd-/- tumor cells re-started proliferation upon long-term culture. This was accompanied by rewiring of oncogenic gene expression and signaling pathways, while mTORC1 signaling remained permanently disabled in CTSD-deficient cells. Together, these studies reveal a tumor cell-autonomous effect of CTSD deficiency, and establish a pivotal role of this protease in the cellular response to oncogenic stimuli.


Assuntos
Neoplasias da Mama/metabolismo , Catepsina D/genética , Epitélio/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Animais , Neoplasias da Mama/genética , Catepsina D/deficiência , Feminino , Humanos , Glândulas Mamárias Animais/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais
2.
Nat Commun ; 11(1): 4642, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32934200

RESUMO

Epigenetic regulation plays an important role in governing stem cell fate and tumorigenesis. Lost expression of a key DNA demethylation enzyme TET2 is associated with human cancers and has been linked to stem cell traits in vitro; however, whether and how TET2 regulates mammary stem cell fate and mammary tumorigenesis in vivo remains to be determined. Here, using our recently established mammary specific Tet2 deletion mouse model, the data reveals that TET2 plays a pivotal role in mammary gland development and luminal lineage commitment. We show that TET2 and FOXP1 form a chromatin complex that mediates demethylation of ESR1, GATA3, and FOXA1, three key genes that are known to coordinately orchestrate mammary luminal lineage specification and endocrine response, and also are often silenced by DNA methylation in aggressive breast cancers. Furthermore, Tet2 deletion-PyMT breast cancer mouse model exhibits enhanced mammary tumor development with deficient ERα expression that confers tamoxifen resistance in vivo. As a result, this study elucidates a role for TET2 in governing luminal cell differentiation and endocrine response that underlies breast cancer resistance to anti-estrogen treatments.


Assuntos
Diferenciação Celular , Proteínas de Ligação a DNA/metabolismo , Estradiol/metabolismo , Estrogênios/metabolismo , Glândulas Mamárias Animais/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/fisiopatologia , Linhagem da Célula , Metilação de DNA , Proteínas de Ligação a DNA/genética , Sistema Endócrino/metabolismo , Epigênese Genética , Receptor alfa de Estrogênio/genética , Receptor alfa de Estrogênio/metabolismo , Feminino , Humanos , Glândulas Mamárias Animais/fisiopatologia , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas/genética
3.
Life Sci ; 259: 118375, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32891612

RESUMO

OBJECTIVE: Short-chain fatty acids were reported to be the precursors of milk fat and can stimulate the de novo synthesis of fatty acids in bovine mammary epithelial cells (bMECs). However, the mechanism has not been elucidated. The purpose of this study was to investigate the effects of sodium butyrate (NaB) on milk fat synthesis in bMECs and explore its potential mechanism. METHODS: Bovine mammary epithelial cells (bMECs) were isolated for subsequent experimental uses. BODIPY staining and triglyceride kit were used to detect the milk fat synthesis in bMECs. Western blotting and RT-PCR assays were performed to detect the expression of related genes in bMECs. Immunoprecipitation was used to detect the acetylation of SREBP1 in bMECs. RESULTS: The results showed that NaB significantly promoted milk fat synthesis, promoted the activity of mechanistic target of rapamycin (mTOR) and S6 kinase (S6K), inhibited the activity of AMP-activated protein kinase (AMPK), and promoted the gene expression of G protein-coupled receptor 41 (GPR41). Knockdown of GPR41 and sterol regulatory element binding protein 1 (SREBP1) and overexpression of sirtuin1 (SIRT1), mTOR inhibitor (rapamycin), and AMPK activator (AICIR) eliminated these effects. These results indicated that NaB increased the nuclear translocation of SREBP1 via the GPR41/AMPK/mTOR/S6K signalling pathway, promoted the acetylation of mature SREBP1a via GPR41/AMPK/SIRT1, and then promoted milk fat synthesis. CONCLUSION: Taken together, these results demonstrated that NaB increased nuclear translocation and acetylation of SREBP1 to promote milk fat synthesis by activating GPR41 and its downstream signalling pathways.


Assuntos
Ácido Butírico/farmacologia , Glicolipídeos/biossíntese , Glicoproteínas/biossíntese , Glândulas Mamárias Animais/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Western Blotting , Carbazóis , Bovinos , Células Cultivadas , Feminino , Imunoprecipitação , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Glândulas Mamárias Animais/metabolismo , Naftalenos , Reação em Cadeia da Polimerase em Tempo Real , Sirtuína 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
4.
Life Sci ; 260: 118415, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32918974

RESUMO

AIMS: Previous studies have shown the effect of niacin on dairy cow production, but no study on the role of niacin in milk fat synthesis has been performed. Therefore, the purpose of this study was to examine the effect of niacin on milk fat synthesis and its specific mechanism in BMECs. MAIN METHODS: In this study, 0.5 mM niacin, a GPR109A-inhibiting plasmid, and an AMPK inhibitor were added to BMECs. Milk fat was measured by a triglyceride kit and BODIPY staining. The protein expression of GPR109A, FASN, SREBP1, AMPK, ACC, mTOR and S6K was measured by Western blotting. The gene expression of GPR109A, FASN, and SREBP1 was analysed by RT-PCR. KEY FINDINGS: Our results showed that 0.5 mM niacin could significantly reduce milk fat synthesis in BMECs and activate the AMPK/ACC signalling pathway by stimulating GPR109A, reducing the protein expression of p-mTOR and p-S6K, and reducing the expression of SREBP1 and FASN in BMECs. SIGNIFICANCE: The present study clarified the effect of niacin on milk fat synthesis. The results show that niacin inhibits the synthesis of milk fat in BMECs through the downstream signalling pathway mediated by GPR109A. The function of niacin has been expanded, and knowledge of the new mechanism and signalling pathway will help improve the biosynthesis of milk fat.


Assuntos
Gorduras na Dieta/metabolismo , Células Epiteliais/metabolismo , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo , Niacina/farmacologia , Receptores Acoplados a Proteínas-G/metabolismo , Animais , Bovinos , Células Epiteliais/efeitos dos fármacos , Feminino , Hipolipemiantes/farmacologia , Glândulas Mamárias Animais/efeitos dos fármacos , Leite/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/genética
5.
PLoS One ; 15(8): e0236516, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776970

RESUMO

Breast cancer is the most common cause of cancer-related deaths in women worldwide. Identification of reliable prognostic indicators and therapeutic targets is critical for improving patient outcome. Cancer in companion animals often strongly resembles human cancers and a comparative approach to identify prognostic markers can improve clinical care across species. Feline mammary tumors (FMT) serve as models for extremely aggressive triple negative breast cancer (TNBC) in humans, with high rates of local and distant recurrence after resection. Despite the aggressive clinical behavior of most FMT, current prognostic indicators are insufficient for accurately predicting outcome, similar to human patients. Given significant heterogeneity of mammary tumors, there has been a recent focus on identification of universal tumor-permissive stromal features that can predict biologic behavior and provide therapeutic targets to improve outcome. As in human and canine patients, collagen signatures appear to play a key role in directing mammary tumor behavior in feline patients. We find that patients bearing FMTs with denser collagen, as well as longer, thicker and straighter fibers and less identifiable tumor-stromal boundaries had poorer outcomes, independent of the clinical variables grade and surgical margins. Most importantly, including the collagen parameters increased the predictive power of the clinical model. Thus, our data suggest that similarities with respect to the stromal microenvironment between species may allow this model to predict outcome and develop novel therapeutic targets within the tumor stroma that would benefit both veterinary and human patients with aggressive mammary tumors.


Assuntos
Colágeno/metabolismo , Neoplasias Mamárias Animais/cirurgia , Prognóstico , Neoplasias de Mama Triplo Negativas/cirurgia , Animais , Gatos , Colágeno/genética , Modelos Animais de Doenças , Feminino , Humanos , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Glândulas Mamárias Animais/cirurgia , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/metabolismo , Neoplasias Mamárias Animais/patologia , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Microambiente Tumoral/genética
6.
Anticancer Res ; 40(8): 4701-4706, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32727795

RESUMO

BACKGROUND/AIM: Bovine mastitis is caused by the invasion and propagation of pathogenic microorganisms into the udder and mammary gland tissues of cattle. In this study, the therapeutic effect of a low-molecular-weight whey protein (LMW-WP) on bovine mastitis was evaluated. MATERIALS AND METHODS: LMW-WP was orally, intraperitoneally, and vaginally administered to bovine with mastitis. The number of somatic cells in milk was measured 24 h before the administration of LMW-WP. The effect of LMW-WP on cytokine production was measured with a microarray that evaluates the expression of cytokines. RESULTS: In the group that received 1,000 mg intraperitoneally, the somatic cell count was reduced to less than 400,000 at the shipment standard value in three of the four udders, indicating 75% efficacy. The group that received 1,000 mg by vaginal administration showed 67% efficacy. It was confirmed that LMW-WP increased the production of cytokines such as IL-5, IL-6, IL-9, IL-12, MCP-1, and VEGF in mouse macrophage cells, but it did not show any antibacterial activity. CONCLUSION: LMW-WP may be an effective therapeutic agent for bovine mastitis.


Assuntos
Macrófagos/efeitos dos fármacos , Mastite Bovina/tratamento farmacológico , Proteínas do Soro do Leite/farmacologia , Animais , Antibacterianos/farmacologia , Bovinos , Contagem de Células/métodos , Linhagem Celular , Citocinas/metabolismo , Feminino , Glândulas Mamárias Animais/metabolismo , Mastite Bovina/microbiologia , Camundongos , Leite/metabolismo , Células RAW 264.7
7.
Anticancer Res ; 40(7): 3697-3705, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32620608

RESUMO

BACKGROUND/AIM: Time restricted feeding (TRF) mitigates the high-fat diet-enhanced mammary tumorigenesis in a MMTV-PyMT breast cancer model. MATERIALS AND METHODS: We performed untargeted metabolomic and targeted transcriptomic analyses on mammary tumors from MMTV-PyMT mice fed a standard AIN93G diet, a high-fat diet (HFD), or HFD with TRF (12 h, dark phase) and mammary glands from wild-type mice fed the AIN93G diet. RESULTS: The metabolic profile of mammary tumors differed from that of mammary glands; there was no impact of TRF upon tumor metabolome. TRF did reduce elevated expression of Hmgcr, Srebp1, Fads2, and Ppard in mammary tumors, indicating a down-regulation of lipid metabolism. CONCLUSION: The null effect of TRF on the metabolomic profile does not rule out changes in more refined intracellular signaling pathways. It suggests that the protection of TRF against mammary tumorigenesis may rely upon its action on the host rather than a direct effect on tumor metabolism.


Assuntos
Glândulas Mamárias Animais/metabolismo , Neoplasias Mamárias Animais/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Metaboloma/fisiologia , Obesidade/metabolismo , Animais , Carcinogênese/metabolismo , Dieta Hiperlipídica/métodos , Modelos Animais de Doenças , Regulação para Baixo/fisiologia , Feminino , Metabolismo dos Lipídeos/fisiologia , Masculino , Camundongos
8.
PLoS One ; 15(7): e0235619, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32634174

RESUMO

This study aimed to estimate energy requirements of pregnant Holstein × Gyr cows. Different planes of nutrition were established by two feeding regimens: ad libitum or maintenance. Sixty-two nonlactating cows with average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. Cows were divided into three groups: pregnant (n = 44), non-pregnant (n = 12), and baseline reference (n = 6). The 56 pregnant and non-pregnant cows were randomly allocated into a feeding regimen: ad libitum or maintenance. To evaluate the effects of days of pregnancy, pregnant and non-pregnant animals were slaughtered at 140, 200, 240, and 270 days of pregnancy. Energy requirements for maintenance differed between pregnant and non-pregnant cows, thus two equations were developed. Net energy and metabolizable energy requirements for maintenance of non-pregnant cows were 82 kcal/kg empty body weight0.75/day and 132 kcal/kg empty body weight0.75/day, respectively. The efficiency of use of metabolizable energy for maintenance of non-pregnant cows was 62.4%. Net energy and metabolizable energy for maintenance of pregnant cows were 86 kcal/kg empty body weight0.75/day and 137 kcal/kg empty body weight0.75/day, respectively. Efficiency of use of metabolizable energy for maintenance of pregnant cows was 62.5%. The efficiency of use of metabolizable energy for gain was 41.9%. The efficiency of use of metabolizable energy for pregnancy was 14.1%. Furthermore, net energy requirement for pregnancy was different from zero from day 70 of pregnancy onwards. In conclusion, net energy and metabolizable energy requirements for maintenance of non-pregnant cows are different from pregnant cows. Furthermore, we believe that the proposed non-linear equations to estimate net energy requirements for pregnancy are more adequate than current NRC equation, and should be recommended for Holstein × Gyr cows.


Assuntos
Ingestão de Energia , Necessidades Nutricionais , Animais , Peso Corporal , Bovinos , Metabolismo Energético , Feminino , Glândulas Mamárias Animais/metabolismo , Gravidez , Útero/metabolismo
9.
Gene ; 759: 144981, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32707300

RESUMO

Peroxisome proliferator-activated receptor gamma (PPARG), as a member of the nuclear receptor superfamily, plays an important role in adipocyte differentiation and regulation of lipid and glucose metabolism. In this study, the transcripts of PPARG gene were isolated and identified in buffalo mammary gland. The results showed that two types of transcripts (PPARG1 and PPARG2) of PPARG gene produced by alternative 5' end use were expressed in buffalo mammary gland, and each of them had four different alternative splicing variants. The PPARG1 includes PPARG1a, PPARG1b, PPARG1c and PPARG1d, while the PPARG2 contains PPARG2a, PPARG2b, PPARG2c and PPARG2d. Among them, only PPARG1a, PPARG2a and PPARG2d can encode complete functional proteins with three complete functional domains, and the rest encode truncated proteins with incomplete functional domains. All the eight variants of PPARG protein do not contain transmembrane regions and signal peptides, but their conserved domain, secondary and tertiary structure and subcellular localization were different. Subcellular localization confirmed that the main transcripts PPARG1a and PPARG2a played a functional role in the nucleus, which was consistent with the results by in silico prediction. RT-qPCR analysis of buffalo mammary tissue showed that the mRNA expression levels of PPARG1 and PPARG2 in lactation were higher than those in non-lactation, and the expression levels of transcripts PPARG2d and PPARG1b + PPARG2b in lactating stage were also higher than those in non-lactating stage, but the mRNA abundance of transcripts PPARG1c, PPARG1d and PPARG2c in non-lactating period was higher than that in lactating period. The results of this study suggest that PPARG1 and PPARG2 may play important role in buffalo milk fat synthesis, and the eight alternative splicing variants found here are likely to be related to the post-transcriptional regulation of lactation.


Assuntos
Búfalos/genética , Glândulas Mamárias Animais/metabolismo , PPAR gama/genética , Animais , Feminino , Lactação/genética , Leite/metabolismo , PPAR gama/metabolismo
10.
PLoS One ; 15(6): e0234427, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32511270

RESUMO

MicroRNAs (miRNAs) play an important role in regulating mammary gland development and lactation. We previously analyzed miRNA expression profiles in Laoshan dairy goat mammary glands at the early (20 d postpartum), peak (90 d postpartum) and late lactation (210 d postpartum) stages. To further enrich and clarify the miRNA expression profiles during the lactation physiological cycle, we sequenced miRNAs in the mammary gland tissues of Laoshan dairy goats at three newly selected stages: the late lactation (240 d postpartum), dry period (300 d postpartum) and late gestation (140 d after mating) stages. We obtained 4038 miRNAs and 385 important miRNA families, including mir-10, let-7 and mir-9. We also identified 754 differentially expressed miRNAs in the mammary gland tissue at the 3 different stages and 6 groups of miRNA clusters that had unique expression patterns. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that GO terms such as mammary gland development (GO:0030879) and mammary gland morphogenesis (GO:0060443) and important signaling pathways, including the insulin signaling pathway (chx04910), hippo signaling pathway (chx04390) and estrogen signaling pathway (chx04915), were enriched. We screened miRNAs and potential target genes that may be involved in the regulation of lactation, mammary gland growth and differentiation, cell apoptosis, and substance transport and synthesis and detected the expression patterns of important genes at the three stages. These miRNAs and critical target genes may be important factors for mammary gland development and lactation regulation and potentially valuable molecular markers, which may provide a theoretical reference for further investigation of mammary gland physiology.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Cabras/fisiologia , Lactação/genética , Glândulas Mamárias Animais/crescimento & desenvolvimento , MicroRNAs/metabolismo , Gravidez/genética , Animais , Apoptose/genética , Indústria de Laticínios , Estrogênios/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Glândulas Mamárias Animais/metabolismo , Análise de Sequência de RNA , Transdução de Sinais/genética
11.
J Dairy Sci ; 103(7): 6218-6232, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32418692

RESUMO

Amino acids and glucose have been shown to regulate protein synthesis in the mammary gland through their effects on cellular signaling pathways. Acetate might also have an effect on protein synthesis via the AMP-activated kinase signaling pathway, because it is the main energy source for the mammary secretory cell. Thus, the objective of this experiment was to evaluate the effects of casein and energy-yielding nutrients (acetate and glucose), and their combination, on performance and mammary metabolism. Six multiparous Holstein cows, averaging 49 kg of milk/d, were used in a 6 × 6 Latin square design with 14-d periods. Cows were fed to 100% National Research Council requirements for metabolizable protein (MP) and energy (ME) for 9 d, after which they were feed-restricted for 5 d to 85% of their individual ad libitum intake and then abomasally infused with 1 of 6 treatments. Treatments were acetate (A), glucose (G), each at 5% of ad libitum ME intake, casein (C) at 15% of ad libitum MP intake, A + C, G + C, or a saline solution (negative control). Casein infused alone increased milk protein yield numerically, with 25% recovery of the infused casein in milk protein. Glucose infused alone increased milk and milk protein yield and promoted the highest efficiency of nitrogen utilization (37%), with an efficiency of MP use for milk protein of 58%. We discovered no effect of treatment on mammary plasma flow, and the increase in milk protein yield with glucose infusion was brought about by greater mammary AA clearance rate. Infusion of casein and glucose together further increased milk protein yield in an additive fashion, and 47% of the infused casein was recovered in milk protein. Acetate infused alone had no effect on milk protein yield but increased milk fat yield numerically, suggesting that the greater amount of acetate taken up by the mammary gland was used for milk fat synthesis. Infusion of acetate and casein together yielded responses similar to those of casein alone. In conclusion, glucose has a major effect on stimulating milk protein synthesis, and the mammary gland has the ability to increase its supply of nutrients to match its synthetic capacity.


Assuntos
Caseínas/administração & dosagem , Bovinos , Glucose/administração & dosagem , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/biossíntese , Abomaso/metabolismo , Acetatos/análise , Aminoácidos/metabolismo , Animais , Caseínas/metabolismo , Feminino , Hipersensibilidade Alimentar , Trato Gastrointestinal , Glucose/metabolismo , Lactação/fisiologia , Glândulas Mamárias Animais/efeitos dos fármacos , Leite/química , Proteínas do Leite/análise , Biossíntese de Proteínas
12.
Oncogene ; 39(24): 4728-4740, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32404986

RESUMO

An epithelial to mesenchymal transition (EMT) is an embryonic dedifferentiation program which is aberrantly activated in cancer cells to acquire cellular plasticity. This plasticity increases the ability of breast cancer cells to invade into surrounding tissue, to seed metastasis at distant sites and to resist to chemotherapy. In this study, we have observed a higher expression of interferon-related factors in basal-like and claudin-low subtypes of breast cancer in patients, known to be associated with EMT. Notably, Irf1 exerts essential functions during the EMT process, yet it is also required for the maintenance of an epithelial differentiation status of mammary gland epithelial cells: RNAi-mediated ablation of Irf1 in mammary epithelial cells results in the expression of mesenchymal factors and Smad transcriptional activity. Conversely, ablation of Irf1 during TGFß-induced EMT prevents a mesenchymal transition and stabilizes the expression of E-cadherin. In the basal-like murine breast cancer cell line 4T1, RNAi-mediated ablation of Irf1 reduces colony formation and cell migration in vitro and shedding of circulating tumor cells and metastasis formation in vivo. This context-dependent dual role of Irf1 in the regulation of epithelial-mesenchymal plasticity provides important new insights into the functional contribution and therapeutic potential of interferon-regulated factors in breast cancer.


Assuntos
Transição Epitelial-Mesenquimal , Fator Regulador 1 de Interferon/biossíntese , Glândulas Mamárias Animais/metabolismo , Neoplasias Mamárias Experimentais/metabolismo , Proteínas de Neoplasias/biossíntese , Animais , Linhagem Celular Tumoral , Feminino , Fator Regulador 1 de Interferon/genética , Glândulas Mamárias Animais/patologia , Neoplasias Mamárias Experimentais/genética , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Metástase Neoplásica , Proteínas de Neoplasias/genética
13.
Cancer Sci ; 111(7): 2336-2348, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32437590

RESUMO

Dietary fat consumption during accelerated stages of mammary gland development, such as peripubertal maturation or pregnancy, is known to increase the risk for breast cancer. However, the underlying molecular mechanisms are not fully understood. Here we examined the gene expression profile of mouse mammary epithelial cells (MMECs) on exposure to a high-fat diet (HFD) or control diet (CD). Trp53-/- female mice were fed with the experimental diets for 5 weeks during the peripubertal period (3-8 weeks of age). The treatment showed no significant difference in body weight between the HFD-fed mice and CD-fed mice. However, gene set enrichment analysis predicted a significant enrichment of c-Myc target genes in animals fed HFD. Furthermore, we detected enhanced activity and stabilization of c-Myc protein in MMECs exposed to a HFD. This was accompanied by augmented c-Myc phosphorylation at S62 with a concomitant increase in ERK phosphorylation. Moreover, MMECs derived from HFD-fed Trp53-/- mouse showed increased colony- and sphere-forming potential that was dependent on c-Myc. Further, oleic acid, a major fatty acid constituent of the HFD, and TAK-875, an agonist to G protein-coupled receptor 40 (a receptor for oleic acid), enhanced c-Myc stabilization and MMEC proliferation. Overall, our data indicate that HFD influences MMECs by stabilizing an oncoprotein, pointing to a novel mechanism underlying dietary fat-mediated mammary carcinogenesis.


Assuntos
Dieta Hiperlipídica , Epitélio/metabolismo , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Maturidade Sexual , Animais , Linhagem Celular Tumoral , Feminino , Genes p53 , Humanos , Camundongos , Camundongos Knockout , Obesidade/etiologia , Obesidade/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Puberdade , Células Tumorais Cultivadas
14.
PLoS One ; 15(5): e0231168, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365127

RESUMO

Staphylococcus aureus is one of the most important pathogens causing mastitis in dairy cows. The objective of this study was to establish a rat model of mastitis induced by S. aureus infection and to explore changes in the proteomes of mammary tissue in different udder states, providing a better understanding of the host immune response to S. aureus mastitis. On day 3 post-partum, 6 rats were randomly divided into two groups (n = 3), with either 100 µL of PBS (blank group) or a S. aureus suspension containing 2×107 CFU·mL-1 (challenge group) infused into the mammary gland duct. After 24 h of infection, the rats were sacrificed, and mammary gland tissue was collected. Tandem mass tag (TMT)-based technology was applied to compare the proteomes of healthy and mastitic mammary tissues. Compared with the control group, the challenge group had 555 proteins with significant differences in expression, of which 428 were significantly upregulated (FC>1.2 and p<0.05) and 127 were downregulated (FC>0.83 and p<0.05 or p<0.01). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that upregulated differentially significant expressed proteins (DSEPs) were associated with mainly immune responses, including integrin alpha M, inter-α-trypsin inhibitor heavy chain 4, and alpha-2-macroglobulin. This study is the first in which a rat model of S. aureus-induced mastitis was used to explore the proteins related to mastitis in dairy cows by TMT technology, providing a model for replication of dairy cow S. aureus-induced mastitis experiments.


Assuntos
Glândulas Mamárias Animais/metabolismo , Mastite/metabolismo , Proteoma/análise , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/fisiologia , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Feminino , Glândulas Mamárias Animais/microbiologia , Glândulas Mamárias Animais/patologia , Mastite/microbiologia , Mastite/patologia , Gravidez , Proteoma/metabolismo , Proteômica/métodos , Ratos , Ratos Sprague-Dawley , Infecções Estafilocócicas/patologia , Espectrometria de Massas em Tandem
15.
Nat Commun ; 11(1): 2649, 2020 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-32461571

RESUMO

Pregnancy causes a series of cellular and molecular changes in mammary epithelial cells (MECs) of female adults. In addition, pregnancy can also modify the predisposition of rodent and human MECs to initiate oncogenesis. Here, we investigate how pregnancy reprograms enhancer chromatin in the mammary epithelium of mice and influences the transcriptional output of the oncogenic transcription factor cMYC. We find that pregnancy induces an expansion of the active cis-regulatory landscape of MECs, which influences the activation of pregnancy-related programs during re-exposure to pregnancy hormones in vivo and in vitro. Using inducible cMYC overexpression, we demonstrate that post-pregnancy MECs are resistant to the downstream molecular programs induced by cMYC, a response that blunts carcinoma initiation, but does not perturb the normal pregnancy-induced epigenomic landscape. cMYC overexpression drives post-pregnancy MECs into a senescence-like state, and perturbations of this state increase malignant phenotypic changes. Taken together, our findings provide further insight into the cell-autonomous signals in post-pregnancy MECs that underpin the regulation of gene expression, cellular activation, and resistance to malignant development.


Assuntos
Glândulas Mamárias Animais/metabolismo , Animais , Carcinogênese/genética , Transformação Celular Neoplásica/patologia , Epigênese Genética , Epigenoma , Células Epiteliais/metabolismo , Feminino , Regulação da Expressão Gênica , Glândulas Mamárias Animais/citologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oncogenes/genética , Gravidez , Complicações na Gravidez/etiologia , Complicações na Gravidez/genética , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
16.
Nanotoxicology ; 14(6): 740-756, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32401081

RESUMO

Despite numerous studies on the environmental health and safety (EHS) of silver nanoparticles (AgNPs), most studies looked into their gross toxicities with rather limited understanding on their labyrinthine implicit effects on the target sites, such as the endocrine system. Burgeoning evidence documents the disrupting effects of AgNPs on endocrine functions; however, little research has been invested to recognize the potential impacts on the mammary gland, a susceptible estrogen-responsive organ. Under this setting, we here aimed to scrutinize AgNP-induced effects on the development of pubertal mammary glands at various concentrations that bear significant EHS relevance. We unearthed that AgNPs could accumulate in mouse mammary glands and result in a decrease in the percentage of ducts and terminal ducts in the adult mice after chronic exposure. Strikingly, smaller sized AgNPs showed greater capability to alter the pubertal mammary development than larger sized particles. Intriguingly, mechanistic investigation revealed that the reduction of epithelial proliferation in response to AgNPs was ascribed to reduced ERα expression, which, at least partially, accounted for diseased epithelial morphology in mammary glands. Meanwhile, the decline in fibrous collagen deposition around the epithelium was found to contribute to the compromised development of mammary glands under the exposure of AgNPs. Moreover, as an extension of the mechanism, AgNPs diminished serum levels of estradiol in exposed animals. Together, these results uncovered a novel toxicity feature of AgNPs: compromised development of mouse pubertal mammary glands through the endocrine-disrupting actions. This study would open a new avenue to unveil the EHS impacts of AgNPs.


Assuntos
Disruptores Endócrinos/toxicidade , Estrogênios/metabolismo , Glândulas Mamárias Animais/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Animais , Relação Dose-Resposta a Droga , Disruptores Endócrinos/farmacocinética , Epitélio/efeitos dos fármacos , Epitélio/crescimento & desenvolvimento , Epitélio/metabolismo , Receptor alfa de Estrogênio/metabolismo , Estrogênios/farmacologia , Feminino , Glândulas Mamárias Animais/crescimento & desenvolvimento , Glândulas Mamárias Animais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Tamanho da Partícula , Transdução de Sinais , Prata/farmacocinética , Propriedades de Superfície , Distribuição Tecidual
17.
J Dairy Sci ; 103(7): 6627-6634, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32389479

RESUMO

The l-type amino acid transporter 1 (LAT1; also known as SLC7A5) is a transporter that allows the uptake of large neutral amino acids into mammalian cells. In dairy cows, LAT1 is highly expressed in lactating mammary tissues and involved in milk protein synthesis. Prolactin (PRL) has a lactogenic role and is capable of inducing milk production in ruminants. However, the relationship between PRL stimulation and LAT1 expression in dairy cow mammary gland has not been well understood. In this study, we showed that PRL stimulation increased expression of LAT1 and ß-casein in mammary epithelial cells of dairy cows. The stimulatory effect of PRL on milk protein production was inhibited by LAT1-specific inhibitor or LAT1 knockdown, suggesting that PRL-induced milk protein production is involved in LAT1 expression. To determine whether the PRL signaling pathway participates in regulation of LAT1 expression, PRLR (PRL receptor) or STAT5 (signal transducer and activator of transcription 5) was knocked down by short interfering (si)RNA in mammary epithelial cells of dairy cows. Western blot results showed that knockdown of PRLR or STAT5 with siRNA markedly decreased PRL-stimulated LAT1 expression. In addition, we observed a marked increase in plasma membrane expression of LAT1 in PRL-stimulated cells compared with control cells. These observations indicated that PRL signaling can regulate LAT1 expression and activity in mammary epithelial cells of dairy cows, contributing to increased amino acid availability and milk protein synthesis in mammary gland of dairy cow.


Assuntos
Bovinos/fisiologia , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Leite/química , Prolactina/farmacologia , Fator de Transcrição STAT5/metabolismo , Transdução de Sinais , Animais , Caseínas/metabolismo , Células Epiteliais/metabolismo , Feminino , Lactação , Transportador 1 de Aminoácidos Neutros Grandes/genética , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/metabolismo , Biossíntese de Proteínas , Fator de Transcrição STAT5/genética
18.
Breast Cancer Res ; 22(1): 41, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32370801

RESUMO

BACKGROUND: In utero endocrine disruption is linked to increased risk of breast cancer later in life. Despite numerous studies establishing this linkage, the long-term molecular changes that predispose mammary cells to carcinogenic transformation are unknown. Herein, we investigated how endocrine disrupting compounds (EDCs) drive changes within the stroma that can contribute to breast cancer susceptibility. METHODS: We utilized bisphenol A (BPA) as a model of estrogenic endocrine disruption to analyze the long-term consequences in the stroma. Deregulated genes were identified by RNA-seq transcriptional profiling of adult primary fibroblasts, isolated from female mice exposed to in utero BPA. Collagen staining, collagen imaging techniques, and permeability assays were used to characterize changes to the extracellular matrix. Finally, gland stiffness tests were performed on exposed and control mammary glands. RESULTS: We identified significant transcriptional deregulation of adult fibroblasts exposed to in utero BPA. Deregulated genes were associated with cancer pathways and specifically extracellular matrix composition. Multiple collagen genes were more highly expressed in the BPA-exposed fibroblasts resulting in increased collagen deposition in the adult mammary gland. This transcriptional reprogramming of BPA-exposed fibroblasts generates a less permeable extracellular matrix and a stiffer mammary gland. These phenotypes were only observed in adult 12-week-old, but not 4-week-old, mice. Additionally, diethylstilbestrol, known to increase breast cancer risk in humans, also increases gland stiffness similar to BPA, while bisphenol S does not. CONCLUSIONS: As breast stiffness, extracellular matrix density, and collagen deposition have been directly linked to breast cancer risk, these data mechanistically connect EDC exposures to molecular alterations associated with increased disease susceptibility. These alterations develop over time and thus contribute to cancer risk in adulthood.


Assuntos
Disruptores Endócrinos/toxicidade , Matriz Extracelular/patologia , Glândulas Mamárias Animais/patologia , Efeitos Tardios da Exposição Pré-Natal/patologia , Células Estromais/patologia , Animais , Compostos Benzidrílicos/toxicidade , Estrogênios não Esteroides/farmacologia , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/imunologia , Feminino , Fibroblastos/imunologia , Fibroblastos/patologia , Glândulas Mamárias Animais/efeitos dos fármacos , Glândulas Mamárias Animais/imunologia , Glândulas Mamárias Animais/metabolismo , Camundongos , Fenóis/toxicidade , Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Células Estromais/efeitos dos fármacos , Células Estromais/imunologia , Transcriptoma
19.
J Dairy Sci ; 103(7): 6661-6671, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32359993

RESUMO

The CD44 gene encodes a cell-surface glycoprotein that participates in a variety of biological processes such as cell interactions, adhesion, hematopoiesis, and tumor metastasis. We compared the transcriptome in bovine mammary epithelial cells (bMEC) of Chinese Holstein dairy cows producing milk of high and low fat contents. Our results suggest that CD44 might be a candidate gene affecting milk fat synthesis. In the present study, the overexpression of the CD44 gene increased the contents of intracellular triglycerides (TG) and cholesterol (CHOL), whereas knockdown of the CD44 gene decreased bMEC CHOL and TG contents. Gas chromatography analysis of fatty acid composition showed that the contents of α-linolenic acid, palmitic acid, and cis-8,11,14-eicosatrienoic acid were altered due to changes in the level of expression of the CD44 gene. Additionally, elaidic acid, palmitoleic acid, tridecanoic acid, and oleic acid were markedly reduced in the CD44 gene overexpression group compared with the control group. On the contrary, cis-5,8,11,14-eicosatetraenoic acid and stearic acid were markedly increased in the CD44 knockdown group compared with the control group. And RT2 Profiler PCR array (Qiagen, CLAB24070A Frankfurt, Germany) further suggested that overexpression or knockdown of the CD44 gene altered expression levels of functional genes associated with lipid metabolism. The present data indicate that CD44 plays a key regulatory role in lipid metabolism in bMEC.


Assuntos
Bovinos/genética , Receptores de Hialuronatos/genética , Metabolismo dos Lipídeos/genética , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo , Animais , Bovinos/metabolismo , Contagem de Células , Colesterol/metabolismo , Células Epiteliais/metabolismo , Ácidos Graxos/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Feminino , Alemanha , Receptores de Hialuronatos/fisiologia , Glândulas Mamárias Animais/citologia , Triglicerídeos/metabolismo
20.
J Dairy Sci ; 103(7): 6364-6373, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32307160

RESUMO

Infection and inflammation of the mammary gland, and especially prevention of mastitis, are still major challenges for the dairy industry. Different approaches have been tried to reduce the incidence of mastitis. Genetic selection of cows with lower susceptibility to mastitis promises sustainable success in this regard. Bos taurus autosome (BTA) 18, particularly the region between 43 and 59 Mb, harbors quantitative trait loci (QTL) for somatic cell score, a surrogate trait for mastitis susceptibility. Scrutinizing the molecular bases hereof, we challenged udders from half-sib heifers having inherited either favorable paternal haplotypes for somatic cell score (Q) or unfavorable haplotypes (q) with the Staphylococcus aureus pathogen. RNA sequencing was used for an in-depth analysis of challenge-related alterations in the hepatic transcriptome. Liver exerts highly relevant immune functions aside from being the key metabolic organ. Hence, a holistic approach focusing on the liver enabled us to identify challenge-related and genotype-dependent differentially expressed genes and underlying regulatory networks. In response to the S. aureus challenge, we found that heifers with Q haplotypes displayed more activated immune genes and pathways after S. aureus challenge compared with their q half-sibs. Furthermore, we found a significant enrichment of differentially expressed loci in the genomic target region on BTA18, suggesting the existence of a regionally acting regulatory element with effects on a variety of genes in this region.


Assuntos
Predisposição Genética para Doença , Fígado/metabolismo , Mastite Bovina/imunologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus , Transcriptoma , Animais , Bovinos , Indústria de Laticínios , Suscetibilidade a Doenças/veterinária , Feminino , Haplótipos , Glândulas Mamárias Animais/metabolismo , Mastite Bovina/genética , Fenótipo , Locos de Características Quantitativas , Seleção Genética , Análise de Sequência de RNA , Infecções Estafilocócicas/genética , Staphylococcus aureus/genética , Vacinação/veterinária
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