Histology and histopathology Vol.23, nº4 (2008)
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- PublicationOpen AccessThe role of nitric oxide in remodeling of capillary network in rat interscapular brown adipose tissue after long-term cold acclimation(Murcia : F. Hernández, 2008) Korac, A.; Buzadzic, B.; Petrovic, V.; Vasilijevic, A.; Jankovic, A.; Micunovic, K.; Korac, B.Cold exposure has been shown to increase blood flow in interscapular brown adipose tissue (IBAT). The aim of the present study was to evaluate the role of the L-arginine-nitric oxide (•NO) pathway on IBAT capillary network remodeling and its possible correlation with superoxide anion radical (O2 •–). In the rats that received L-arginine (2.25%) or NG-nitro-L-arginine methyl ester (L-NAME, 0.01%) as a drinking liquid and maintained at room (22±1°C) or low (4±1°C) temperature for 45 days, IBAT capillaries were analyzed by stereology and observed by light and electron microscopy. Additionally, endothelial •NO synthase (eNOS) expression, nitrotyrosine immunoreactivity and both copper zinc superoxide dismutase (CuZnSOD) enzyme activity and immunohistochemical localization were examined. Stereological analyses of IBAT show that the capillary volume density, as well as capillary-tobrown adipocytes ratio, are increased in cold. L-arginine treatment increases, while L-NAME decreases both parameters, compared to respective controls. Those changes were accompanied by capillary dilatation observed by light and electron microscopy. The activity of CuZnSOD is lower in control cold-acclimated rats, as well as in both L-arginine-treated groups, when compared to control animals acclimated to room temperature. L-NAME treatment attenuates the effects both of cold and L-arginine on CuZnSOD and increases immunopositivity for CuZnSOD in room temperatureacclimated rats. Our results show that •NO induces remodeling of the IBAT capillary network by angiogenesis, and presumably that interaction with O2 •– has a role in that modulation. The increased eNOS expression accompanied by an increased nitrotyrosine immunoreaction observed in both L-arginine-treated groups compared to corresponding controls strengthens this hypothesis.
- PublicationOpen AccessAluminium exposure induces Alzheimer s disease-like histopathological alterations in mouse brain(Murcia : F. Hernández, 2008) Rodella, L.F.; Ricci, F.; Borsani, E.; Stacchiotti, A.; Foglio, E.; Favero, G.; Rezzani, R.; Mariani, C.; Bianchi, R.Aluminium (Al) is a neurotoxic metal and Al exposure may be a factor in the aetiology of various neurodegenerative diseases such as Alzheimer’s disease (AD). The major pathohistological findings in the AD brain are the presence of neuritic plaques containing ßamyloid (Aß) which may interfere with neuronal communication. Moreover, it has been observed that GRP78, a stress-response protein induced by conditions that adversely affect endoplasmic reticulum (ER) function, is reduced in the brain of AD patients. In this study, we investigated the correlation between the expression of Aß and GRP78 in the brain cortex of mice chronically treated with aluminium sulphate. Chronic exposure over 12 months to aluminium sulphate in drinking water resulted in deposition of Aß similar to that seen in congophilic amyloid angiopathy (CAA) in humans and a reduction in neuronal expression of GRP78 similar to what has previously been observed in Alzheimer’s disease. So, we hypothesise that chronic Al administration is responsible for oxidative cell damage that interferes with ER functions inducing Aß accumulation and neurodegenerative damage.
- PublicationOpen AccessExpression of acyl-CoA synthetase 5 in human epidermis(Murcia : F. Hernández, 2008) Gaisa, N.T.; Köster, J.; Reinartz, A.; Ertmer, K.; Ehling, J.; Raupach, K.; Perez-Bouza, A.; Knüchel, R.; Gassler, N.The human epidermis is characterized by a constant renewal of keratinocytes embedded in a matrix enriched with lipids. Numerous proteins involved in lipid metabolism are found in human epidermis, especially in keratinocytes. Long-chain acyl-CoA derivatives, which are catalyzed by human ACSL5, are important metabolites in several biochemical pathways, including ceramide de novo synthesis. The aim of the present study was to investigate expression of acyl-CoA synthetase isoform 5 (ACSL5) in human epidermis by an in situ, as well as a molecular approach. We show that ACSL5 mRNA and protein are found in human epidermis, as well as in non-differentiated and differentiated HaCaT cells. Keratinocytes of stratum spinosum are the main source for ACSL5 expression in both meshed facial or abdominal skin and ridged skin of upper or lower extremities including TUNEL-positive cells in upper cellular layers. Single keratinocytes of chronic solar-exposed meshed facial epidermis occasionally display a stronger ACSL5 immunostaining. In conclusion, our study indicates that epidermal ACSL5 expression might be involved in differentiation and the stress response of keratinocytes.
- PublicationOpen AccessEvidence for a potential tumor suppressor role for the Na,K-ATPase B1-subunit(Murcia : F. Hernández, 2008) Inge, Landon J.; Rajasekaran, Sigrid A.; Yoshimoto, Koji; Mischel, Paul S.; McBride, William; Landaw, Elliot; Rajasekaran, Ayyappan K.The Na,K-ATPase, consisting of two essential subunits (a, ß), plays a critical role in the regulation of ion homeostasis in mammalian cells. Recent studies indicate that reduced expression of the ß1 isoform (NaK-ß1) is commonly observed in carcinoma and is associated with events involved in cancer progression. In this study, we present evidence that repletion of NaK-ß1 in Moloney sarcoma virustransformed Madin-Darby canine kidney cells (MSVMDCK), a highly tumorigenic cell line, inhibits anchorage independent growth and suppresses tumor formation in immunocompromised mice. Additionally, using an in vitro cell-cell aggregation assay, we showed that cell aggregates of NaK-ß1 subunit expressing MSVMDCK cells have reduced extracellular regulated kinase (ERK) 1/2 activity compared with parental MSV-MDCK cells. Finally, using immunohistochemistry and fully quantitative image analysis approaches, we showed that the levels of phosphorylated ERK 1/2 are inversely correlated to the NaK-ß1 levels in the tumors. These findings reveal for the first time that NaK-ß1 has a potential tumor-suppressor function in epithelial cells.
- PublicationOpen AccessOsteopontin is histochemically detected by the AgNOR acid-silver staining(Murcia : F. Hernández, 2008) Gaudin-Audrain, Christine; Gallois, Yves; Pascaretti-Grizon, Florence; Hubert, Laurent; Massin, Philippe; Baslé, Michael-Félix; Chappard, DanielSilver nitrate staining of decalcified bone sections is known to reveal osteocyte canaliculi and cement lines. Nucleolar Organising Regions (NOR) are part of the nucleolus, containing argyrophilic proteins (nucleoclin/C23, nucleophosmin/B23) that can be identified by silver staining at low pH. The aim of this study was to clarify the mechanism explaining why AgNOR staining also reveals osteocyte canaliculi. Human bone and kidney sections were processed for silver staining at light and electron microscopy with a modified method used to identify AgNOR. Sections were processed in parallel for immunohistochemistry with an antibody direct against osteopontin. Protein extraction was done in the renal cortex and decalcified bone and the proteins were separated by western blotting. Purified hOPN was also used as a control. Proteins were electro-transferred on polyvinylidene difluoride membranes and stained for AgNOR proteins. In bone, Ag staining identified AgNOR in cell nuclei, as well as in osteocyte canaliculi, cement and resting lines. In the distal convoluted tubules of the kidney, silver deposits were also observed in cytoplasmic granules on the apical side of the cells. Immunolocalization of osteopontin closely matched with all these locations in bone and kidney. Ag staining of membranes at low pH revealed bands for NOR proteins and 56 KDa (kidney), 60KDa (purified hOPN) and 75 KDa (bone) bands that corresponded to osteopontin. NOR proteins and osteopontin are proteins containing aspartic acid rich regions that can bind Ag. Staining protocols using silver nitrate at low pH can identify these proteins on histological sections or membranes.
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