RESUMO
Activation of the antiapoptotic protein kinase Akt is induced by a number of growth factors that regulate mammary gland development. Akt is expressed during mammary gland development, and expression decreases at the onset of involution. To address Akt actions in mammary gland development, transgenic mice were generated expressing constitutively active Akt in the mammary gland under the control of the mouse mammary tumor virus (MMTV) promoter. Analysis of mammary glands from these mice reveals a delay in both involution and the onset of apoptosis. Expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), an inhibitor of matrix metalloproteinases (MMPs), is prolonged and increased in the transgenic mice, suggesting that disruption of the MMP:TIMP ratio may contribute to the delayed mammary gland involution observed in the transgenic mice.
Assuntos
Apoptose , Glândulas Mamárias Animais/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Caseínas/genética , Caseínas/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Immunoblotting , Lactação/fisiologia , Glândulas Mamárias Animais/citologia , Vírus do Tumor Mamário do Camundongo/genética , Vírus do Tumor Mamário do Camundongo/metabolismo , Metaloproteinase 3 da Matriz/genética , Metaloproteinase 3 da Matriz/metabolismo , Camundongos , Camundongos Transgênicos , Microscopia de Fluorescência , Proteínas do Leite/genética , Proteínas do Leite/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-akt , Fator de Transcrição STAT3 , Fator de Transcrição STAT5 , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Transativadores/genética , Transativadores/metabolismoRESUMO
In recent years the mitogen-activated protein (MAP) kinase family has expanded to include both c-jun N-terminal kinases (JNKs), and the p38/HOG1 family in addition to the extracellular regulated kinase (ERK) family. These kinases are activated by a variety of growth factors, as well as extra- and intracellular insults such as osmotic stress, UV light, and chemotherapeutic agents. Stimulation of the PRL-dependent Nb2 cell line with PRL results in the rapid activation of JNK as determined by the glutathione-S-transferase (GST)-jun kinase assay. Activation was maximal 30 min after stimulation with 50 nM rat PRL (rPRL) and decreased after that time. Dose response studies indicated that concentrations as low as 10 nM rPRL resulted in maximal activation. The interleukin-3 (IL-3)-dependent myeloid progenitor cell line 32Dcl3 was transfected with the long, Nb2, and short forms of the rat PRL receptor (rPRLR), as well as the long form of the human PRLR (hPRLR). The long and Nb2 forms of the PRLR were able to stimulate activation of JNK; however, the short form of the rPRLR was not. This corresponds with the inability of the short form of the rPRLR to stimulate proliferation of 32Dcl3 cells. Activation of JNK in 32Dcl3 cells expressing the long form of the hPRLR was maximal at 30 min after stimulation with 100 nM ovine PRL (oPRL) and declined after that time. Dose response studies indicated that activation of JNK was maximal after 30 min at a concentration of 10 nM, and the amount of activated JNK declined at the highest concentration of oPRL, 100 nM. Immunoblot analysis with an antibody that recognizes the activated (phosphorylated) forms of JNK1 and JNK2 indicated that both JNK1 and JNK2 isoforms were activated in 32D/hPRLR cells stimulated with oPRL. A recombinant human adenovirus expressing a kinase-inactive mutant of JNK1 (APF mutant) was used to determine the biological effect of blocking JNK activity in Nb2 cells. Expression of the JNK1-APF mutant inhibited cellular proliferation and induced DNA fragmentation typical of cells undergoing apoptosis. These data suggest that activation of JNKs may be important in mitogenic signaling and/or suppression of apoptosis in Nb2 cells.
Assuntos
Proteínas Quinases JNK Ativadas por Mitógeno , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Prolactina/farmacologia , Animais , Apoptose , Divisão Celular , Linhagem Celular , Ativação Enzimática/efeitos dos fármacos , Glutationa Transferase/metabolismo , Granulócitos , Humanos , Interleucina-3/farmacologia , Cinética , MAP Quinase Quinase 4 , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteína Quinase 8 Ativada por Mitógeno , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Ratos , Receptores da Prolactina/química , Receptores da Prolactina/genética , Receptores da Prolactina/fisiologia , Proteínas Recombinantes , Ovinos , Células-Tronco , Relação Estrutura-Atividade , TransfecçãoRESUMO
The mouse mammary gland is a complex tissue, which is continually undergoing changes in structure and function. Embryonically, the gland begins with invasion of the underlying fat pad by a rudimentary ductal structure. Postnatal growth occurs in two phases: ductal growth and early alveolar development during estrous cycles, and cycles of proliferation, differentiation, and death that occur with each pregnancy, lactation, and involution. The variety of epithelial structures and stromal changes throughout the life of a mammary gland makes it a challenge to study. The purpose of this histological review is to give a brief representation of the morphological changes that occur throughout the cycle of mouse mammary gland development so that developmental changes observed in mouse models of mammary development can be appreciated.
Assuntos
Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/crescimento & desenvolvimento , Envelhecimento , Animais , Diferenciação Celular , Divisão Celular , Estro , Feminino , Lactação , Glândulas Mamárias Animais/embriologia , Camundongos , Gravidez , Maturidade SexualRESUMO
Interstitial cystitis, neurogenic disturbances of bladder emptying resulting from incomplete supranuclear lesions and idiopathic detrusor hyperreflexia are clinically always associated with frequency, nocturia, urgency or urgency incontinence (urge syndrome). These disturbances of bladder emptying are difficult to distinguish, even urodynamically. With selective sacral nerve blockade, it is possible to differentiate between forms urodynamically using a nerve-blocking anesthetic. Reversible selective sacral nerve blockade is also the treatment for idiopathic detrusor hyperreflexia.