The effect of 17ß-estradiol on the expression of dipeptidyl peptidase III and heme oxygenase 1 in liver of CBA/H mice.

BACKGROUND: 17ß-estradiol (E2) has well-established cardioprotective, antioxidant and neuroprotective role, and exerts a vast range of biological effects in both sexes. Dipeptidyl peptidase III (DPP III) is protease involved as activator in Keap1-Nrf2 signalling pathway, which is important in cellular defense to oxidative and electrophilic stress. It is generally accepted that oxidative stress is crucial in promoting liver diseases. OBJECTIVE: To examine the effect of E2 on the expression of DPP III and haeme oxygenase 1 (HO-1) in liver of adult CBA/H mice of both sexes. METHODS: Gene and protein expressions of studied enzymes were determined by quantitative real-time PCR and Western blot analysis. Immunohistochemistry was performed to analyse the localization of both proteins in different liver cell types. RESULTS: Ovariectomy diminished expression of DPP III and HO-1 proteins. E2 administration abolished this effect, and even increased these proteins above the control. A significant enhancement in DPP III protein was found in E2-treated males, as well. A decrease in the expression of HO-1, but not of the DPP III gene, was detected in the liver of ovariectomized females. HO-1 protein was found localized in the pericentral areas of hepatic lobules (Kupffer cells and hepatocytes), whilst DPP III showed a uniform distribution within hepatic tissue. CONCLUSIONS: We demonstrate for the first time that E2 influences the protein level of DPP III in vivo, and confirm earlier finding on HO-1 gene upregulation by 17ß-estradiol. These results additionally confer new insights into complexity of protective action of E2.

nNOS expression in reactive astrocytes correlates with increased cell death related DNA damage in the hippocampus and entorhinal cortex in Alzheimer's disease.

The immunocytochemical distribution of the neuronal form of nitric oxide synthase (nNOS) was compared with neuropathological changes and with cell death related DNA damage (as revealed by in situ end labeling, ISEL) in the hippocampal formation and entorhinal cortex of 12 age-matched control subjects and 12 Alzheimer's disease (AD) patients. Unlike controls, numerous nNOS-positive reactive astrocytes were found in AD patients around beta-amyloid plaques in CA1 and subiculum and at the places of clear and overt neuron loss, particularly in the entorhinal cortex layer II and CA4. This is the first evidence of nNOS-like immunoreactivity in reactive astrocytes in AD. In contrast to controls, in all but one AD subject, large numbers of ISEL-positive neuronal nuclei and microglial cells were found in the CA1 and CA4 regions and subiculum. Semiquantitative analysis showed that neuronal DNA fragmentation in AD match with the distribution of nNOS-expressing reactive astroglial cells in CA1 (r = 0.74, P < 0.01) and CA4 (r = 0.58, P < 0.05). A portion of the nNOS-positive CA2/CA3 pyramidal neurons was found to be spared even in the most affected hippocampi. A significant inverse correlation between nNOS expression and immunoreactivity to abnormally phosphorylated tau proteins (as revealed by AT8 monoclonal antibody) in perikarya of these CA2/3 neurons (r = -0.85, P < 0.01) suggests that nNOS expression may provide selective resistance to neuronal degeneration in AD. In conclusion, our results imply that an upregulated production of NO by reactive astrocytes may play a key role in the pathogenesis of AD.

Ultrastructural analysis and TUNEL demonstrate motor neuron apoptosis in Werdnig-Hoffmann disease.

Werdnig-Hoffmann disease (WHD) is the most severe clinical type of spinal muscular atrophy characterized by loss of lower motor neurons and paralysis. We examined the hypothesis that disease pathogenesis is based on an inappropriate persistence of normally occurring motor neuron programmed cell death. The diagnosis of WHD was made on the basis of clinical findings, electromyoneurography, and biopsy, and further confirmed by mutation analysis of the survival motor neuron (SMN) and neuronal apoptosis inhibitory protein (NAIP) genes using PCR. We used ultrastructural analysis as well as TUNEL and ISEL methods to assess DNA fragmentation, and immunocytochemistry to identify expression of the apoptosis-related proteins bcl-2 and p53. A significant number of motor neurons in the spinal cord of children with WHD were shown to die by apoptosis. As revealed by TUNEL, dying neurons in WHD patients comprised 0.2%-6.4% of the neuron numbers counted. This finding contradicts earlier studies that failed to find such evidence and suggests that early blockade of prolonged motor neuron apoptosis may be a potential therapeutic strategy for WHD.

Entorhinal cortex lesion does not alter reelin messenger RNA expression in the dentate gyrus of young and adult rats.

The extracellular matrix protein reelin plays an important role in neuronal pattern formation and axonal collateralization during the development of the central nervous system. With the concept that reelin might also be important for axonal growth in the injured nervous system we investigated whether reelin is re-expressed in areas of collateral sprouting after brain injury. The expression of reelin messenger RNA was studied in the denervated fascia dentata of adult rats one, four, seven and 14 days following entorhinal cortex lesion. In adult control animals, in situ hybridization histochemistry with digoxigenin-labeled reelin riboprobes revealed reelin messenger RNA expression in neurons located in the outer molecular layer and beneath the granule cell layer of the dentate gyrus. After entorhinal cortex lesion, this expression pattern did not change during the whole post-lesional time period investigated despite a strong glial activation and reactive sprouting in the outer molecular layer of the dentate gyrus as visualized by immunohistochemistry for glial fibrillary acidic protein and acetylcholinesterase histochemistry, respectively. The expression of reelin messenger RNA was also unaffected by entorhinal cortex lesion in the dentate gyrus of young animals (postnatal day seven), where an even stronger sprouting response occurs.