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1

Minocycline administration protects tight junction proteins from degradation after pre-chiasmatic subarachnoid hemorrhange in rats

100%
Gendosz D., Debska K., Jedrzejewska-Szypulka H., Lewin-Kowalik J.
Acta Neurobiologiae Experimentalis
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2015
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tom 75
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nr Supl.
BACKGROUND AND AIMS: Subarachnoid hemorrhage has complex, multisystem and multifaceted pathogenesis that involves several ongoing pathological processes, including BBB degradation. Our aim was to survey potential protective properties of minocycline on Tight Junctions (TJ) proteins in rat brain, after experimentally induced pre-chiasmatic SAH (pSAH). METHODS: pSAH was induced by injection of 200 μL of fresh autologous arterial blood into pre-chiasmatic cistern in rat brain. Minocycline was administrated ip twice, at 1st and 10th h after surgery (dose: 30 mg/kg). 24 h following the surgery, animals were perfused transcardialy and whole brains were collected. In order to investigate immuno-localization of TJ proteins, coronal sections were immuno-stained against Zonulin-1, Occludin and Claudin-5. ZO-1, OCN, CLN-5 proteins levels were examined by WB reactions. RESULTS: We observed numerous blood vessels around the site of blood application as well in more distant areas, where we found essential alterations in immunostaining patterns of ZO-1, OCN and CLN-5, comparing to controls. Minocycline administration preserves physiological ZO-1 and OCN cellular localization comparing to SAH group. Subsequently we provided WB reactions to define SAH impact on TJ protein level. We observed that SAH leads to significant decrease in both OCN and ZO-1 protein level in first 24 h after ictus. Important message comes from the minocycline experiment. We found out significant increase of ZO-1 level comparing to SAH group. Though OCN doesn’t reach significance, we can observe some positive trend in minocycline group. CONCLUSIONS: Administration of arterial blood directly to prechiasmatic cistern leads to serious affections of TJ integrity during first 24 h after pSAH. Minocycline protects TJ proteins from degradation and also preserves TJ unit from morphological alterations at the level of brain vessel endothelium.
2

Solid pituitary adenoma in Eker rats subjected to ketogenic diet

100%
Liskiewicz A., Gendosz D., Jedrzejowska-Szypulka H., Lewin-Kowalik J.
Acta Neurobiologiae Experimentalis
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2013
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tom 73
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nr Suppl.1
Tuberous sclerosis (TS) is a genetic disease causing non-malignant tumors growth in the brain (e.g. pituitary adenoma) and in other organs. Ketogenic diet is already used in TS patients in treatment of epilepsy. However the mechanism of its influence on tumor growth is still not clear. The Eker rat is a useful model of TS: it has a spontaneous germ line mutation of the TSC2 gene what predisposed them to multiple tumors. In Eker rats, pituitary adenomas are common, occurring in 58% of adults (more than 18-months-old). Methods: Forty six 8-month-old Eker rats (males and females) were used. Twenty six (experimental group) have been maintained on high fat, low carbohydrate ketogenic diet for 6 months, while 20 (control group) received a standard rodent diet. At the age of 14 months rats were sacrificed. Anteroposterior, vertical, and transverse diameters of the found pituitary adenomas were measured. Size of tumors was calculated by using the formula for volume of the ellipsoid. Results: 8% animals from experimental group and 20% from control group have developed pituitary adenomas. Mean tumor volume in experimental group was 143 mm2 vs. 217 mm2 in control animals. Conclusion: Eker rats fed with ketogenic diet develops solid pituitary adenoma in 14 months of age. Incidence of these pituitary tumors in Eker rats fed with ketogenic diet (8%) was lower when compared with rats from control group (20%).
3

Role of metalloproteinases in synoptic plasticity in hippocampal mossy fiber-CA3 pathway

76%
Mozrzymas J. W., Wojtowicz T., Wiera G., Gendosz D., Chmielewska M., Wawrzyniak M.
Acta Neurobiologiae Experimentalis
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2011
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tom 71
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nr S
Matrix metalloproteinases (MMPs) are widely recognized as endopeptidases involved in remodeling of extracellular matrix. Last decade studies revealed these enzymes as important regulators of synaptic plasticity and cognitive processes. In particular, MMPs inhibition led to impairment of hippocampus-dependent learning and to down regulation of long-term potentiation (LTP) maintenance in the Schaffer collateral– CA1 (SC-CA1) pathway. However, the impact of MMPs on plasticity in other hippocampal paths was not known. In our recent studies, we have we addressed the impact of MMPs on plasticity in mossy fiber-CA3 (mf-CA3) projection in which, in contrast to SC-CA1, LTP expression in presynaptic. We found that pharmacological blockade of MMPs nearly abolished the late phase of LTP. Induction of LTP resulted in increased immunoreactivity for MMP-9 and enhanced gelatinase activity (in situ zymography) and these effects were associated with up regulation of de novo expression of active and latent MMP-9 forms (gel zymography). Interestingly, the late phase of LTP in the mf-CA3 pathway was reduced both in the MMP-9 KO mice and in rats overexpressing MMP-9. This finding indicates that maintenance of synaptic plasticity requires an optimal, finely tuned MMP-9 activity level. Pyramidal neurons in the CA3 region form a dense autoassociative network due to associational/commissural (AC) projections and plasticity mechanisms in AC and mf-CA3 synapses are different. Recently, we found that the late LTP phase in the AC synapses is also impaired by MMPs inhibition. Moreover, EPSC-spike potentiation in the CA3 region is strongly down regulated by MMPs blockade. In conclusion, MMPs appear to play a universal role in consolidation of synaptic plasticity in various hippocampal pathways characterized by different mechanisms of synaptic plasticity. Supported by Ministry for Science and Higher Education grants PN/030/2006 and N N401 541540.
4

Induction of long term potentiation in DG-CA3 hippocampal pathway results in increased MMP-2/9 gelatinolysis in target hilar and CA3 neurons

64%
Wojtowicz T., Gendosz D., Lebida K., Drulis-Fajdasz D., Wiera G., Caponga M., Wilczynski G., Dziegiel P., Mozrzymas J. W.
Acta Neurobiologiae Experimentalis
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2011
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tom 71
|
nr S
Matrix metalloproteinases (MMPs) are capable of remodeling extracellular matrix and have been implicated in synaptic plasticity, learning and memory. In particular, upregulation of gelatinases (MMP-2 and 9) accompanies long-term potentiation (LTP) in hippocampal Schaeffer collateral-CA1 pathway. However, the role of gelatinases in synaptic plasticity in other hippocampal pathways remains unknown. Recently, we have found that MMPs blockade by FN-439 abolishes LTP consolidation in the dentate gyrus-CA3 (DG-CA3) projection (where LTP expression is presynaptic, Wójtowicz and Mozrzymas 2010). To address the involvement of gelatinases in the plasticity of this pathway, we have combined high resolution in situ zymography with DQ-gelatin (DQ-G) and immunofluorescence in hippocampal sections from slices used in electrophysiological experiments. LTP was evoked by high frequency stimulation (HFS, 4×100 Hz) while baseline (control) stimulation was applied at 0.1 Hz. Following fixation, slices were cut into thin sections, treated with DQ-G and stained against a neuronal marker MAP-2. The intensity of DQ-G fluorescence was quantified for MAP-2 positive neurons using confocal microscopy. Computer- and visually-guided analysis of cytoplasm and proximal dendrites of target hilar and CA3 neurons revealed that LTP induction was associated with a significant increase in DQ-G fluorescence (30% and 35% increase, respectively, n=6 animals, p<0.05). Importantly, cytoplasmic DQ-G fluorescence profile corroborated with immunoreactivity for MMP-9. The overall DQ-G fluorescence signal in MAP-2 and GFAP-negative extracellular space did not differ between control and HFS-stimulated preparations (n=6 animals, p=0.89). In conclusion, we provide evidence that stimulation pattern that evokes LTP in the DG-CA3 pathway, induces a significant up regulation of gelatinases in the cytoplasm of postsynaptic hilar and CA3 neurons. Support: Grants NN401541540 and UDA-POKL.04.01.01-00-010/08-01.
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