Impairment of pelvic organ support has been described in mice with genetic modifications of the proteins involved in elastogenesis, such as lysyl oxidase-like 1 (LOXL1) and fibulin 5. During pregnancy, elastic fiber-enriched pelvic tissues are modified to allow safe delivery. In addition, the mouse pubic symphysis is remodeled in a hormone-controlled process that entails the modification of the fibrocartilage into an interpubic ligament (IpL) and the relaxation of this ligament. After first parturition, recovery occurs to ensure pelvic tissue homeostasis. Because ligaments are the main supports of the pelvic organs, this study aimed to evaluate elastogenesis in the IpL during mouse pregnancy and postpartum. Accordingly, virgin, pregnant, and postpartum C57BL/6 mice were studied using light, confocal, and transmission electron microscopy as well as Western blots and real-time PCR. Female mice exhibited the separation of the pubic bones and the formation, relaxation, and postpartum recovery of the IpL. By the time the IpL was formed, the elastic fibers had increased in profile length and diameter, and they consisted of small conglomerates of amorphous material distributed among the bundles of microfibrils. Our analyses also indicated that elastin/tropoelastin, fibrillin 1, LOXL1/Loxl1, and fibulin 5 were spatially and temporally regulated, suggesting that these molecules may contribute to the synthesis of new elastic fibers during IpL development. Overall, this work revealed that adult elastogenesis may be important to assure the elasticity of the pelvic girdle during preparation for parturition and postpartum recovery. This finding may contribute to our understanding of pathological processes involving elastogenesis in the reproductive tract.
The mechanism underlying castration-induced prostate regression, which is a classical physiological concept translated into the therapeutic treatment of advanced prostate cancer, involves epithelial cell apoptosis. In searching for events and mechanisms contributing to prostate regression in response to androgen modulation, we have frequently observed the collective deletion of epithelial cells. This work was undertaken to characterize this phenomenon hereafter named desquamation and to verify its presence after 17β-estradiol (E2) administration. Electron microscopy revealed that the desquamating cells had preserved cell-cell junctions and collapsed nuclear contents. The TUNEL reaction was negative for these cells, which were also negative for cleaved caspases-8, -9, -3 and nuclear apoptosis-inducing factor. Detailed analyses revealed that the condensed chromatin was first affected detaching from the nuclear lamina, which was observable after lamin A immunohistochemistry, suggesting the lack of lamin A degradation. A search in animals treated with supraphysiological E2 employed as an alternative anti-androgen treatment revealed no desquamation. The combined treatment (Cas + E2 group) caused changes particular to each treatment, including desquamation. In conclusion, desquamation appeared as a novel phenomenon contributing to collective prostate epithelial cell deletion, distinct from the classical castration-induced apoptosis and particular to the androgen deprivation resulting from surgical castration, and should be considered as part of the mechanisms promoting organ regression.
Oestrogen exposure during the early post-natal period affects male growth, physiology, and susceptibility to disease in adult life. The prostate gland is susceptible to this oestrogen imprinting, showing a reduced expression of the androgen receptor and inability to respond to androgen stimulus. In this context, we decided to study key signalling regulators of ventral prostate (VP) functioning after early postnatal exposure to high-dose oestrogen. Our results showed a decrease of mTOR phosphorylation and its direct downstream target 4EBP. It is known that mTOR-induced signalling is a pivotal pathway of cell metabolism, which is able to control gene transcription and protein synthesis. We then decided to investigate other indicators of a reduced metabolism in the oestrogenized prostate, and found that the luminal epithelial cells were shorter, less polarized and had smaller nuclei containing more compacted chromatin, suggesting that a general mechanism of regulating gene expression and protein synthesis could be installed in the epithelium of the oestrogenized VP. To evaluate this idea, we analysed nucleolar morphology, and measured the amount of ribosomes and the level of methylation of the 45S ribosomal RNA promoter region. These data indicated that the nucleolus was dismantled and that the methylation at the 45S promoter was increased ( approximately five-fold). Taken together, the results support the idea that the oestrogenized prostate maintains a very low transcriptional level and protein turnover by affecting canonical signalling pathways and promoting nuclear and nucleolar changes.
We built a complete and non-redundant database of bZIP transcriptional regulatory factors from the Arabidopsis reference genome. These Arabidopsis bZIP factors were ordered into thirteen families of evolutionary related proteins and this classification was used to identify and organize sugarcane cDNAs encoding bZIP proteins. We also show how this classification should help in defining putative clusters of orthologous groups of higher plant bZIP regulators and briefly discuss the expected benefits of this procedure to efficiently characterize sugarcane bZIP transcriptional regulators.
A possibilidade de uso por compartilhamento de equipamentos de pesquisa oferecida pelos programas EMU (Equipamentos Multiusuário, Fapesp), aliada à tendência de documentação digital de dados proporcionou uma oportunidade de difusão de conhecimento, através do oferecimento de treinamento em microtomografia computadorizada para alunos da universidade. Assim, no IB, uma parceria entre o LMBCM (Laboratório Multiusuário de Biologia Celular e Molecular/DBEF-IB) e o Herbário UEC proporcionou o treinamento de bolsistas do SAE em microtomografia e representação 3D de sementes do acervo do Herbário, que futuramente constituirá uma carpoteca digital, oferecendo um acervo digital para conhecimento anatômico de sementes.
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