doktorska disertacija
Mićo Božić (Author), Matjaž Stenovec (Mentor), Robert Zorec (Co-mentor)

Abstract

Astrociti so homeostatične celice centralnega živčevja, ki se odzivajo na patološke dražljaje s procesom aktivacije. Vnetni citokin interferon γ (IFNγ) v astrocitih inducira izražanje molekul poglavitnega histokompatibilnostnega kompleksa razreda II (MHCII), ki so potrebne za predstavitev antigenov. Izolirane astrocite tradicionalno gojimo v celični kulturi s serumom, ki poveča bazalno raven aktivacije in spremeni njihovo morfologijo ter znotrajcelično signalizacijo s kalcijevimi ioni. Vpliv obeh prožilcev aktivacije astrocitov na elementarne dogodke ekso-/endocitoze v astrocitih je nepoznan. V delu smo zato raziskali dinamiko in lastnosti elementarnih dogodkov ekso-/endocitoze v podganjih netretiranih serumskih astrocitih, serumskih astrocitih, tretiranih z IFNγ in astrocitih v brezserumski kulturi. Znotrajcelično porazdelitev imunofluorescenčno označenih molekul MHCII smo analizirali s konfokalno mikroskopijo in mikroskopijo s strukturirano osvetlitvijo, lastnosti elementarnih dogodkov ekso-/endocitoze smo raziskali z meritvami membranske kapacitivnosti z metodo vpete napetosti krpice membrane. V astrocitih, tretiranih z IFNγ, so se molekule MHCII lokalizirale pretežno v pozne endo-/lizosome, vendar so dosegle tudi plazmalemo. Z njo so prehodno interagirali večji eksocitotski mešički, medtem ko so bili inhibirani dogodki popolne endocitoze. Ekso-/endocitotska dejavnost brezserumskih astrocitov je bila primerljiva z dejavnostjo serumskih astrocitov v spontanih razmerah, medtem ko je bil zavrt njihov ekso-/endocitotski odziv na draženje z ATP. Aktivacija astrocitov v kulturi z IFNγ ali serumom spremeni dinamiko elementarnih dogodkov ekso-/endocitoze in podaljša zadrževanje molekul MHCII na površini.

Keywords

astrociti;eksocitoza;endocitoza;aktivacija astrocitov;predstavitev antigenov;serum;elektrofiziologija;meritve kapacitivnosti;doktorske disertacije;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UL MF - Faculty of Medicine
Publisher: [M. Božić]
UDC: 576.3:611.8(043.3)=163.6
COBISS: 49776643 Link will open in a new window
Views: 518
Downloads: 91
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Other data

Secondary language: English
Secondary title: Elementary exocytotic and endocytotic events in activated cultured astrocytes
Secondary abstract: Astrocytes are homeostatic glial cells in the central nervous system that respond to pathologic changes with a process of activation. Interferon γ (IFNγ), an inflammatory cytokine, induces astrocyte expression of major histocompatibility class II (MHCII) molecules required for antigen presentation. Isolated astrocytes are traditionally cultured with serum; however, serum increases astrocyte basal activation and alters their morphology and intracellular calcium signalling. The impact of both triggers of astrocyte activation on exo-/endocytotic activity in astrocytes is not understood. We have thus studied the properties and dynamics of exo-/endocytotic events in non-treated and IFNγ-treated serum as well as serum-free cultured rat astrocytes. The intracellular distribution of immunofluorescently labelled MHCII molecules was analysed with confocal and structural illumination microscopies. Furthermore, elementary exo-/endocytotic activity was studied by patch clamp membrane capacitance measurements. In IFNγ-treated astrocytes, MHCII molecules predominantly localized to late endo-/lysosomes, but also reached the plasmalemma. Additionally, larger exocytotic vesicles reversibly interacted with the plasmalemma, while full endocytotic events were inhibited. Exo-/endocytotic activity of astrocytes in serum-free culture was unaltered at rest, however their exo-/endocytotic activity in response to ATP stimulation was suppressed. Activated cultured astrocytes instigated by treatment with IFNγ or serum culture supplementation display altered dynamics of elementary exo-/endocytotic activity and prolonged surface retention of MHCII.
Secondary keywords: astrocytes;exocytosis;endocytosis;astrocyte activation;antigen presentation;serum;electrophysiology;capacitance measurements;
Type (COBISS): Doctoral dissertation
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak.
Pages: XII f., 89 str.
ID: 12349038