This dissertation provides a comprehensive and systematic examination of anthropoid primate milk composition and its relationship to a species' evolutionary history, ecological context, and life history strategy. Milk samples from 14 species of anthropoid primate (Alouatta paliatta, Callithrix jacchus, Cebus apella, Gorilla beringei beringei, Gorilla gorilla gorilla, Hylobates lar, Leontopithecus rosalia, Macaca mulatta, Macaca sinica, Pan paniscus, Pan troglodytes, Pongo pygmaeus, Saimiri boliviensis boliviensis, and Symphalangus syndactylus) were analyzed for proximate composition (fat, protein, lactose, dry matter, and minerals) and milk fatty acid composition. The objectives of this study were identification of primitive features in anthropoid milks, shared-derived features of anthropoid families or superfamilies, and unique-derived features of species, including Homo sapiens.Results did not support the null hypothesis of a generalized anthropoid milk composition. Variation among anthropoids in milk fatty acid profiles and proximate milk composition was influenced by phylogeny and the life history strategy of the species, as well as the diet and environment (captive or wild living) of the mother.Maternal diet had a direct influence on fatty acid profiles and created distinct groupings of wild and captive living individuals. Phylogenetic patterns were identified within captive and wild groups, particularly a distinction between milk fatty acid profiles of hominoids (including humans) and monkeys.Significant variation in proximate milk composition was identified at the level of the superfamily. Cercopithecoid milk was highest in mean fat, dry matter, the proportion of energy from fat, and total gross energy. Ceboid milk was highest in mean protein and the proportion of energy from protein. Hominoid milks were lowest in mean fat, protein, dry matter, the proportion of energy from fat, and total gross energy.Hominoid milk also was lowest in the degree of plasticity in milk composition. Milk of captive living monkeys was higher than milk of wild living monkeys in mean fat, percent energy from fat, and total gross energy. Milk fat and energy also were highly variable within captive living monkeys. In contrast, fat and total gross energy were not significantly different between captive and wild living hominoids and were less variabile among captive living hominoids as compared to monkeys. The lack of variability and the relatively low energy values in hominoid milk suggest that it may be buffered against environmental fluctations. Larger body size and a longer duration of lactation may permit hominoids, including humans, to decouple maternal condition from milk energy and instead relying on energy storage.

It is well known that DNA methylation in gene promoter regions inhibits gene transcription and that tissue-specific gene expression is partially under the control of this transcription regulatory mechanism. In this study, bovine mammary gland tissues were collected from individual animals in lactating and non-lactating stages to investigate the DNA methylation patterns in the kappa-casein gene and alpha-lactalbumin gene core promoter regions using the bisulphite treatment in combination with polymerase chain reaction (PCR) sequencing. Different methylation status of each sample was classified into three categories, namely methylation at known transcription factor binding domains, methylation at core promoter non-binding domains and the absence of cytosine methylation. Real-time quantitative PCR was used to quantify the transcription levels of the kappa-casein and alpha-lactalbumin genes from the collected samples. A comparative method was used and fold-change values were calculated based on the comparison of the normalized threshold values of samples from different physiological stages as well as on various methylation patterns observed in their core promoter regions. Statistical analyses showed that the expressions of the kappa-casein and alpha-lactalbumin genes were significantly different in lactating and non-lactating mammary gland tissues. The methylation observed in the core promoter region of bovine alpha-lactalbumin gene was found to be associated with its gene expression. On the other hand, the methylation found in the core promoter region of bovine kappa-casein gene did not have any effect on its gene transcript levels.

The fps proto-oncogene encodes a 92 kDa cytoplasmic tyrosine kinase. Previous studies have shown that Fps expression in the mammary gland changes with development, and Fps has a suppressor function in mammary tumorigenesis. The aim of my thesis was to elucidate the role of the Fps tyrosine kinase in regulating mammary gland development and function. We have shown that the expression of the Fps kinase in the mammary gland increased during pregnancy and reached its maximum during lactation. The level of Fps tyrosine phosphorylation paralleled the expression pattern. Pups reared by fps-null females gained weight more slowly than those reared by wild-type females. Epithelial cells were the primary source of Fps expression. Milk protein and fat content were not affected by the absence of Fps. Similarly, no differences in mammary gland structure were observed with whole mount or histological analysis. Fps was shown to be in a multi-protein complex with E-cadherin, β-catenin and p120-catenin. A strong co-localization signal was observed for Fps and E-cadherin. Immunofluorescence analysis indicated that the localization of E-cadherin and β-catenin was disorganized and less concentrated at sites of cell-cell contacts in the fps-null glands. The interactions between the different adherens junction components were altered in the fps-null tissue. Specifically, less E-cadherin and β-catenin was associated with p120-catenin in the fps-null glands. Suprisingly, no phosphotyrosine differences were detected for the adherens junction components. Conditions were established to grow primary murine epithelial cell cultures that could be used to investigate the function of Fps. Fps expression was up-regulated in these cells in response to lactogenic hormones. A lentiviral system encoding a murine p53 shRNA sequence was used to increase the growth potential of the primary cells. Continual growth of the infected and uninfected primary epithelial cell mixture resulted in the establishment of an immortalized cell line. Immunofluorescent and immunoblot analyses revealed that the cells have undergone an epithelial-to-mesenchymal transition. With the transduction of a myc-epitope tagged Fps into the cells, we have generated cell lines with the appropriate genetic backgrounds to study the function of the Fps kinase in the mammary gland, specifically as it relates to tumorigenesis. / Thesis (Ph.D, Pathology & Molecular Medicine) -- Queen's University, 2008-07-03 11:53:01.135

No description available.

The role of plasmin and plasminogen activators (PA) in bovine lactation and porcine ovulation has been examined. There is no difference in the activation pattern of plasminogen to plasmin throughout the whole range of somatic cell counts (SCC) and from third to ninth month in lactation. The ratio of (plasminogen + plasmin)/plasmin, which serves as an index of the activation process, was 7.27 during early (first and second month) and 4.23 during late lactation (tenth month) and both values are different (p $<$ 0.01) from all the other ratios throughout the whole range of SCC and from third to ninth month in lactation suggesting limited and increased activation of plasminogen to plasmin during early and late lactation, respectively. Macrophages produce but they do not secrete urokinase-PA, suggesting a minor role in influencing milk plasmin. Somatotropin administration resulted in a suppression of milk plasmin in vivo. Insulin-like growth factor-1 (IGF-1), the most likely mediator of the effects of somatotropin on the bovine mammary gland, inhibited the induction of tissue-PA (t-PA) production which is observed when mammary epithelial cells are cultured in the absence of IGF-1. Plasmin and t-PA increased while PA inhibitor-1 decreased in porcine granulosa, theca interna cells and follicular fluid just prior to the time of expected ovulation suggesting a role for plasmin in follicle rupture.

Rat exon microarrays were utilized to detect changes in mRNA expression and alternative splicing in the liver, duodenum, jejunum, and ileum of the lactating rat when compared to age-matched virgin controls. Analysis of data at the level of gene expression revealed differential expression of genes involved in cholesterol biosynthesis in each tissue examined, suggesting increased Sterol Response Element Binding Protein activity. We also detected decreased mRNA from components of the T-cell signaling pathway in the jejunum and ileum. We characterized expression of solute carrier and adenosine triphosphate binding cassette proteins. In addition to characterizing genes by pathway, we have also grouped genes based on their pattern of expression to identify important genes. Amongst genes upregulated in all tissues was Slc39a4, which is a critical transporter in the absorption of zinc in enterocytes. Alternative splicing analysis detected a substantial amount of alternative splicing in the ileum compared to other tissues. In addition, in the liver Abcg8, a protein that functions as a heterodimer to export cholesterol in the bile, shows differential splicing in the liver, but not in other tissues. We also detected differential expression of Ugt1a6 in the liver based on usage of an alternative first exon, which is consistent with altered protein levels observed previously. Differential splicing also appears to occur in Ace2 in the ileum, which could have consequences on the renin-angiotensin pathway.

No description available.

Calcium is the major mineral component of milk and is essential for neonatal development. To enrich the milk, calcium must pass from the maternal bloodstream, through mammary epithelial cells, into the alveolar lumen. While calcium extrusion from the epithelial cells is well characterized, no calcium channel or transporter has been identified as the major conduit for calcium to enter the mammary epithelial cell from the bloodstream. A major aim of this thesis was to identify a calcium channel or channels responsible for calcium influx into mammary epithelial cells during lactation. Real time reverse transcription-polymerase chain reaction was used to investigate in vivo expression of calcium channels in the murine mammary gland at the four main stages of mammary gland development. The store-operated calcium channel Orai1 was upregulated during lactation relative to its expression in the nulliparous gland. The classic ORAI1 regulator Stim1 was not similarly overexpressed during lactation, however, its isoform Stim2 was modestly upregulated. HC11 murine mammary cells were used as a model to further investigate the role of STIM2 on calcium handling during lactation. siRNA knockdown of Stim2 reduced both basal and agonist-induced peak cytosolic calcium levels, indicative of its role in calcium regulation. In addition to investigating the role of calcium channels in normal mammary development, their role in breast cancer was examined. Real time reverse transcription-polymerase chain reaction was used to identify calcium channels upregulated in human breast cancer cell lines, relative to non-tumorigenic mammary cell lines. TRPV1, TRPV6, and ORAI1 were upregulated in the breast cancer cell lines. Pharmacological modulation of ORAI1 resulted in modest changes in proliferation, but as there was no specific ORAI1 inhibitor, this effect could not be conclusively attributed to ORAI1 inhibition. siRNA was used to specifically target ORAI1 in three human breast cancer cell lines: MCF-7, MDA-MB-231, and T-47D. siRNA knockdown of ORAI1 was specific and potent, and reduced cell viability and altered calcium handing in all three cell lines. The alterations caused by ORAI1 knock down were not related to the expression of the genes CDK2 and FOS, as these did not change upon ORAI1 knockdown. Data mining was performed using the National Center for Biotechnology Information’s (NCBI’s) expressed sequence tag (EST) database, dbEST, and the Oncomine database. ORAI1 was elevated in estrogen receptor negative breast cancers and in the basal breast cancer molecular subtype, a subtype that has a poor prognosis. Other data suggested that breast cancer cells with high STIM1 and low STIM2 expression also correlated with the basal breast cancer subtype. These data indicate that ORAI and STIM proteins have a role in the physiological process of lactation as well as in the regulation of tumorigenic pathways in the breast, and particular gene expression profiles may be predictors of disease prognosis.

Calcium is the major mineral component of milk and is essential for neonatal development. To enrich the milk, calcium must pass from the maternal bloodstream, through mammary epithelial cells, into the alveolar lumen. While calcium extrusion from the epithelial cells is well characterized, no calcium channel or transporter has been identified as the major conduit for calcium to enter the mammary epithelial cell from the bloodstream. A major aim of this thesis was to identify a calcium channel or channels responsible for calcium influx into mammary epithelial cells during lactation. Real time reverse transcription-polymerase chain reaction was used to investigate in vivo expression of calcium channels in the murine mammary gland at the four main stages of mammary gland development. The store-operated calcium channel Orai1 was upregulated during lactation relative to its expression in the nulliparous gland. The classic ORAI1 regulator Stim1 was not similarly overexpressed during lactation, however, its isoform Stim2 was modestly upregulated. HC11 murine mammary cells were used as a model to further investigate the role of STIM2 on calcium handling during lactation. siRNA knockdown of Stim2 reduced both basal and agonist-induced peak cytosolic calcium levels, indicative of its role in calcium regulation. In addition to investigating the role of calcium channels in normal mammary development, their role in breast cancer was examined. Real time reverse transcription-polymerase chain reaction was used to identify calcium channels upregulated in human breast cancer cell lines, relative to non-tumorigenic mammary cell lines. TRPV1, TRPV6, and ORAI1 were upregulated in the breast cancer cell lines. Pharmacological modulation of ORAI1 resulted in modest changes in proliferation, but as there was no specific ORAI1 inhibitor, this effect could not be conclusively attributed to ORAI1 inhibition. siRNA was used to specifically target ORAI1 in three human breast cancer cell lines: MCF-7, MDA-MB-231, and T-47D. siRNA knockdown of ORAI1 was specific and potent, and reduced cell viability and altered calcium handing in all three cell lines. The alterations caused by ORAI1 knock down were not related to the expression of the genes CDK2 and FOS, as these did not change upon ORAI1 knockdown. Data mining was performed using the National Center for Biotechnology Information’s (NCBI’s) expressed sequence tag (EST) database, dbEST, and the Oncomine database. ORAI1 was elevated in estrogen receptor negative breast cancers and in the basal breast cancer molecular subtype, a subtype that has a poor prognosis. Other data suggested that breast cancer cells with high STIM1 and low STIM2 expression also correlated with the basal breast cancer subtype. These data indicate that ORAI and STIM proteins have a role in the physiological process of lactation as well as in the regulation of tumorigenic pathways in the breast, and particular gene expression profiles may be predictors of disease prognosis.

Calcium is the major mineral component of milk and is essential for neonatal development. To enrich the milk, calcium must pass from the maternal bloodstream, through mammary epithelial cells, into the alveolar lumen. While calcium extrusion from the epithelial cells is well characterized, no calcium channel or transporter has been identified as the major conduit for calcium to enter the mammary epithelial cell from the bloodstream. A major aim of this thesis was to identify a calcium channel or channels responsible for calcium influx into mammary epithelial cells during lactation. Real time reverse transcription-polymerase chain reaction was used to investigate in vivo expression of calcium channels in the murine mammary gland at the four main stages of mammary gland development. The store-operated calcium channel Orai1 was upregulated during lactation relative to its expression in the nulliparous gland. The classic ORAI1 regulator Stim1 was not similarly overexpressed during lactation, however, its isoform Stim2 was modestly upregulated. HC11 murine mammary cells were used as a model to further investigate the role of STIM2 on calcium handling during lactation. siRNA knockdown of Stim2 reduced both basal and agonist-induced peak cytosolic calcium levels, indicative of its role in calcium regulation. In addition to investigating the role of calcium channels in normal mammary development, their role in breast cancer was examined. Real time reverse transcription-polymerase chain reaction was used to identify calcium channels upregulated in human breast cancer cell lines, relative to non-tumorigenic mammary cell lines. TRPV1, TRPV6, and ORAI1 were upregulated in the breast cancer cell lines. Pharmacological modulation of ORAI1 resulted in modest changes in proliferation, but as there was no specific ORAI1 inhibitor, this effect could not be conclusively attributed to ORAI1 inhibition. siRNA was used to specifically target ORAI1 in three human breast cancer cell lines: MCF-7, MDA-MB-231, and T-47D. siRNA knockdown of ORAI1 was specific and potent, and reduced cell viability and altered calcium handing in all three cell lines. The alterations caused by ORAI1 knock down were not related to the expression of the genes CDK2 and FOS, as these did not change upon ORAI1 knockdown. Data mining was performed using the National Center for Biotechnology Information’s (NCBI’s) expressed sequence tag (EST) database, dbEST, and the Oncomine database. ORAI1 was elevated in estrogen receptor negative breast cancers and in the basal breast cancer molecular subtype, a subtype that has a poor prognosis. Other data suggested that breast cancer cells with high STIM1 and low STIM2 expression also correlated with the basal breast cancer subtype. These data indicate that ORAI and STIM proteins have a role in the physiological process of lactation as well as in the regulation of tumorigenic pathways in the breast, and particular gene expression profiles may be predictors of disease prognosis.