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| Identifier |
000388602 |
| Title |
Delineating the role of autophagy in shaping the autoreactive phenotype of monocytes from patients with Systemic Lupus Erythematosus (SLE) upon IFNa signaling |
| Alternative Title |
Ο ρόλος της αυτοφαγίας στο σχηματισμό του αυτοδραστικού φαινοτύπου των μονοκυττάρων από ασθενείς με Συστηματικό Ερυθυματώδη Λύκο (ΣΕΛ) μέσω της σηματοδότησης από ιντερφερόνη-α |
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Author
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Καμπράνη, Ελένη Γ.
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Thesis advisor
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Γκιρτζιμανάκη, Κατερίνα
Βεργίνης, Παναγιώτης
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Reviewer
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Σπηλιανάκης, Χαράλαμπος
Τοκατλίδης, Κωνσταντίνος
Θεοδωρόπουλος, Παναγιώτης
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| Abstract |
Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder, predominantly affecting females, in which loss of tolerance to nucleic acids and their interacting proteins results in the production of pathogenic autoantibodies that cause inflammation and tissue damage. The pathogenic role of type I IFNs in SLE is supported by a signature of IFN-induced genes in the peripheral blood of patients and from high IFN-a serum levels in active SLE patients, which is associated with high disease activity and severity. Autoreactive monocytes in SLE are characterized by IFNa-dendritic cell-like phenotype and their differentiation and capacity to present self-antigen by major histocompatibility class (MHC-) II proteins has been shown to depend on cell autophagy. Autophagy is a cellular catabolic process that involves degradation of unnecessary or dysfunctional cellular components and relies on the cooperation of autophagosomes with lysosomes.
The aim of this project was to delineate the role of autophagy in shaping the autoreactive phenotype of SLE monocytes upon IFNa signaling. For this purpose, CD14+ monocytes were isolated both from SLE patients and healthy donors and the levels of the autophagic proteins LC3 and P62 were assessed by immunobloting analysis and confocal microscopy. ATG5 and P62 mRNA levels were assessed by Real Time PCR. The same experimental approach was followed in ex vivo treatments of CD14+ healthy monocytes with 10% v/v SLE or healthy serum and recombinant human IFNa 104U/ml. The results from these experiments indicated that SLE monocytes exhibit increased levels of autophagy and that treatment of healthy monocytes with SLE serum or recombinant IFNa can induce autophagy. The antigen presenting capacity of healthy monocytes treated with rIFNa was assessed by flow cytometry for the expression of HLA-DR and CD86 surface markers. The results showed that monocytes have increased antigen presenting capacity when treated with rIFNA. Finally, alterations in the autophagolysosomal pH were observed by conducting immunofluoresence analysis of SLE monocytes compared to healthy controls but also of healthy monocytes treated with rIFNa at different time-points. The acidic autophagolysosomal pH sensitive dye, Lysotracker Red-DND99, exhibited significantly reduced staining implying that the autophagic flux may be deregulated in the lupus milieu. As a consequence, not fully processed self-antigens inside autophagolysosomes could be loaded in the Major Histocompatibility Complex II (MHCII) and subsequently trigger an autoimmune response. It is of great importance to unravel a possible mechanism through which IFNa can result in deregulation of autophagy and the production of autoantibodies not only in the context of lupus but also in other autoimmune diseases. By acquiring this knowledge, more targeted therapeutic approaches could be established to these incurable diseases up until now.
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| Language |
English |
| Subject |
Αυτοφαγία |
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Ιντερφερόνη-α |
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Μονοκύτταρα |
| Issue date |
2014-11-21 |
| Collection
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School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
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Type of Work--Post-graduate theses
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| Views |
289 |
Delineating the role of autophagy in shaping the autoreactive phenotype of monocytes from patients with Systemic Lupus Erythematosus (SLE) upon IFNa signaling
