Study of extracellular matrix and water channels in bovine spongiform encephalopathy

Descripció del recurs: el 26 d'agost de 2008Consultable des del TDXTítol obtingut de la portada digitalitzadaLa matriu extracel·lular (MEC) del sistema nerviós central (SNC) es troba dispersa al neuròpil o formant agregats al voltant de les neurones, anomenats xarxes perineuronals (PNN). La MEC conté proteoglicans de tipus condroitin sulfat (CSPG), àcid hialurònic (AH) i tenascina-R. També es poden trobar proteoglicans de tipus heparan sulfat (HSPG) secretats a la MEC o formant part de la membrana cel·lular. Les aquaporines (AQP) són una família de proteïnes transmembrana que actuen com a canals d'aigua. L'AQP1 i l'AQP4 s'expressen àmpliament al SNC on tenen diverses funcions. Malgrat la importància de totes aquestes molècules, la seva distribució al SNC del ratolí només s'ha descrit parcialment. La distribució histoquímica de les PNNs, l'agrecà, l'AH, els HSPG i l'AQP4 es van valorar semiquantitativament al SNC del ratolí. Els resultats van demostrar que l'agrecà, l'AH i els HSPG tenen una distribució perineuronal, mentre que l'AQP4 té una distribució heterogènia al neuròpil del SNC. Es va observar una correlació inversa entre l'AQP4 i els components de la MEC, suggerint que poden tenir un paper complementari en el manteniment de la homeòstasi de l'aigua. L'AQP4 i els HSPG van presentar una localització comú al neuròpil del SNC. La MEC i les AQPs es van estudiar a la encefalopatia espongiforme bovina (EEB) i a la tremolor ovina. Ambdues malalties pertanyen al grup de les encefalopaties espongiformes transmissibles (EET) o malalties priòniques, les quals es caracteritzen per l'acumulació de proteïna prió resistent (PrPres) al SNC, pèrdua neuronal, degeneració espongiforme i proliferació de cèl·lules glials. L'estudi de la MEC es va desenvolupar en la línia de ratolí transgènic boTg110 infectat intracranialment amb EEB; i en el ratolins C57Bl6 infectats amb RML (una soca de tremolor ovina). En tots dos casos es va observar una alteració molt marcada de la MEC a l'estadi final de les dues malalties. L'AQP1 i l'AQP4 es van estudiar al ratolí boTg110 per immunohistoquímica, i casos naturals d'EEB per immunohistoquímica i western blot. Les dues AQPs estaven sobreexpressades a la membrana dels astròcits a l'estadi terminal de la malaltia en el cas dels ratolins, i en vaques pre-clíniques. Els canvis de la MEC i la sobreexpressió de les AQPs es va correlacionar amb l'acumulació de PrPres, i l'activació de les cèl·lules glials. Per això es va concloure que les alteracions a la MEC, l'AQP1 i l'AQP4 eren conseqüència de l'activació de les cèl·lules glials induïda per la PrPres, i tots aquests canvis podrien produir desequilibris en els iòns i l'aigua al SNC i contribuir a l'aparició de les lesions típiques de les EETs.The extracellular matrix (ECM) of the central nervous system (CNS) is found dispersed in the neuropil or forming aggregates around the neurons called perineuronal nets (PNNs). The ECM mainly contains chondroitin sulphate proteoglycans (CSPG), hyaluronic acid (HA) and tenascin-R. Heparan sulphate proteoglycans (HSPG) can also be secreted in the ECM or be part of the cell membrane. Aquaporins (AQP) are a family of transmembrane proteins that act as water selective channels. AQP1 and AQP4 are widely expressed in the CNS where they play several roles. Nevertheless the importance of these elements, their distribution in the CNS of mice is only partially known. The histochemical distribution of PNNs, aggrecan, HA, HSPGs and AQP4 were semiquantitatively evaluated in the whole CNS of mice. The results showed that aggrecan, HA and HSPGs have a perineuronal distribution, and AQP4 has an heterogeneous distribution throughout the neuropil of the CNS. An inverse correlation between AQP4 and ECM components was observed, suggesting a complementary role in the maintenance of water homeostasis. A common location for AQP4 and HSPGs was also observed in CNS neuropil. ECM and AQPs were studied in bovine spongiform encephalopathy (BSE) and Scrapie. Both diseases belong to the group of animal transmissible spongiform encephalopathies (TSE) or prion diseases. They are characterized by the accumulation of resistant prion protein (PrPres) in the CNS, neuronal loss, spongiform degeneration and glial cell proliferation. The ECM was studied by immunohistochemistry in the transgenic mice boTg110, overexpresing bovine PrPc, intracranially infected with cattle BSE; and in C57BL/6 mice intraperitoneally infected with RML scrapie strain. Both of them showed dramatical ECM disturbances at latest stage of both diseases. AQP1 and AQP4 were studied in boTg110 mice by immunohistochemistry, and in BSE field cases by immunohistochemistry and western blot. Both AQPs were overexpressed in the membrane of astrocytes at terminal stage of the disease in mice with evident clinical signs, and in pre-clinical cattle. The ECM changes and AQPs overexpression were correlated with PrPres accumulation, and activated glial cells. Therefore we conclude that alterations in the ECM, AQP1 and AQP4 are a consequence of glial cell activation induced by PrPres, and both changes could lead to ion and water imbalance in the CNS which could contribute to trigger the typical histopathological features of TSEs

CSF SERPINA3 Levels Are Elevated in Patients With Progressive MS

Multiple sclerosis; SERPINA3Esclerosi múltiple; SERPINA3Esclerosis múltiple; SERPINA3Objective To identify biomarkers associated with progressive phases of MS and with neuroprotective potential. Methods Combined analysis of the transcriptional and proteomic profiles obtained in CNS tissue during chronic progressive phases of experimental autoimmune encephalomyelitis (EAE) with the transcriptional profile obtained during the differentiation of murine neural stem cells into neurons. Candidate biomarkers were measured by ELISA in the CSF of 65 patients with MS (29 with relapsing-remitting MS [RRMS], 20 with secondary progressive MS, and 16 with primary progressive MS [PPMS]) and 30 noninflammatory neurologic controls (NINCs). Results Integrative analysis of gene and protein expression data identified 2 biomarkers, the serine protease inhibitor Serpina3n and the calcium-binding protein S100A4, which were upregulated in chronic progressive EAE and whose expression was induced during neuronal differentiation. Immunofluorescence studies revealed a primarily neuronal expression of S100A4 and Serpina3n during EAE. CSF levels of SERPINA3, the human ortholog of murine Serpina3n, and S100A4 were increased in patients with MS compared with NINCs (SERPINA3: 1,320 vs 838.6 ng/mL, p = 0.0001; S100A4: 1.6 vs 0.8 ng/mL, p = 0.02). Within the MS group, CSF SERPINA3 levels were significantly elevated in patients with progressive forms, mainly patients with PPMS compared with patients with RRMS (1,617 vs 1,129 ng/mL, p = 0.02) and NINCs (1,617 vs 838.6 ng/mL, p = 0.0001). Of interest, CSF SERPINA3 levels significantly correlated with CSF neurofilament light chain levels only in the PPMS group (r = 0.62, p = 0.01). Conclusion These results point to a role of SERPINA3 as a biomarker associated with the progressive forms of MS, particularly PPMS.This work was supported by grants from the Fondo de Investigación Sanitaria (FIS; grant number PI17/00596), Ministry of Science and Innovation, Spain; Generalitat de Catalunya Suport Grups de Recerca (2017 SGR 0527); and the Red Española de Esclerosis Múltiple (RD16/0015/0004) funded by the FIS

El prió de la tremolor ovina atípica no presenta limfotropisme

Dins el marc del programa de vigilància activa de les encefalopaties espongiformes transmissibles (EETs) a Catalunya, el laboratori Priocat del Centre de Recerca en Sanitat Animal (CReSA) ha evidenciat la inexistència de limfotropisme per part de la proteïna resistent associada a la tremolor ovina atípica. Uns resultats que s'extreuen del següent article, on es presenta de forma concomitant una encefalitis vírica -el que implica la formació de fol·licles limfoides a l'encèfal- i una malaltia priònica. Així, mentre els prions de la variant clàssica s'acumulen al teixit limfàtic, els de la variant atípica no ho fan ni tan sols estant presents al cervell.En el marco del programa de vigilancia activa de las encefalopatías espongiformes transmisibles (EETs) de Catalunya, el laboratorio Priocat del Centro de Investigación en Sanidad Animal (CReSA) ha evidenciado la inexistencia de limfotropismo por parte de la proteína resistente asociada al temblor ovino atípico. Unos resultados que se extraen del siguiente artículo, donde se presenta de forma concomitante una encefalitis vírica -lo que implica la formación de folículos linfoides en el encéfalo- y una enfermedad priónica. Así, mientras los priones de la variante clásica se acumulan en el tejido linfático, los de la variante atípica no lo hacen ni siquiera estando presentes en el cerebro.From the active TSE surveillance programme in Catalonia, the Priocat laboratory of animal health research centre (CReSA) has detected a noticeable lack of lymphotropsim as far as scrapie-associated prion protein deposition is concerned. Results described in the paper, where a viral encephalitis -which implies formation of lymphoid follicles in the brain- is concomitant to a prion disease. In the classical strains the prions show a strong affinity for the lymphoid tissue but not in this case, even when follicles are as close as in the same brain

El prió de la tremolor ovina atípica no presenta limfotropisme

Dins el marc del programa de vigilància activa de les encefalopaties espongiformes transmissibles (EETs) a Catalunya, el laboratori Priocat del Centre de Recerca en Sanitat Animal (CReSA) ha evidenciat la inexistència de limfotropisme per part de la proteïna resistent associada a la tremolor ovina atípica. Uns resultats que s'extreuen del següent article, on es presenta de forma concomitant una encefalitis vírica -el que implica la formació de fol·licles limfoides a l'encèfal- i una malaltia priònica. Així, mentre els prions de la variant clàssica s'acumulen al teixit limfàtic, els de la variant atípica no ho fan ni tan sols estant presents al cervell.En el marco del programa de vigilancia activa de las encefalopatías espongiformes transmisibles (EETs) de Catalunya, el laboratorio Priocat del Centro de Investigación en Sanidad Animal (CReSA) ha evidenciado la inexistencia de limfotropismo por parte de la proteína resistente asociada al temblor ovino atípico. Unos resultados que se extraen del siguiente artículo, donde se presenta de forma concomitante una encefalitis vírica -lo que implica la formación de folículos linfoides en el encéfalo- y una enfermedad priónica. Así, mientras los priones de la variante clásica se acumulan en el tejido linfático, los de la variante atípica no lo hacen ni siquiera estando presentes en el cerebro.From the active TSE surveillance programme in Catalonia, the Priocat laboratory of animal health research centre (CReSA) has detected a noticeable lack of lymphotropsim as far as scrapie-associated prion protein deposition is concerned. Results described in the paper, where a viral encephalitis -which implies formation of lymphoid follicles in the brain- is concomitant to a prion disease. In the classical strains the prions show a strong affinity for the lymphoid tissue but not in this case, even when follicles are as close as in the same brain

Central nervous system gene expression changes in a transgenic mouse model for bovine spongiform encephalopathy

Gene expression analysis has proven to be a very useful tool to gain knowledge of the factors involved in the pathogenesis of diseases, particularly in the initial or preclinical stages. With the aim of finding new data on the events occurring in the Central Nervous System in animals affected with Bovine Spongiform Encephalopathy, a comprehensive genome wide gene expression study was conducted at different time points of the disease on mice genetically modified to model the bovine species brain in terms of cellular prion protein. An accurate analysis of the information generated by microarray technique was the key point to assess the biological relevance of the data obtained in terms of Transmissible Spongiform Encephalopathy pathogenesis. Validation of the microarray technique was achieved by RT-PCR confirming the RNA change and immunohistochemistry techniques that verified that expression changes were translated into variable levels of protein for selected genes. Our study reveals changes in the expression of genes, some of them not previously associated with prion diseases, at early stages of the disease previous to the detection of the pathological prion protein, that might have a role in neuronal degeneration and several transcriptional changes showing an important imbalance in the Central Nervous System homeostasis in advanced stages of the disease. Genes whose expression is altered at early stages of the disease should be considered as possible therapeutic targets and potential disease markers in preclinical diagnostic tool development. Genes non-previously related to prion diseases should be taken into consideration for further investigations