Caiazza, Carmen (2021) Knock-out of STING causes impairment of antigen presentation and abolishes STAT1 activation in mouse macrophages. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Resource language: English
Title: Knock-out of STING causes impairment of antigen presentation and abolishes STAT1 activation in mouse macrophages
Date: 14 July 2021
Number of Pages: 98
Institution: Università degli Studi di Napoli Federico II
Department: Medicina Molecolare e Biotecnologie Mediche
Dottorato: Medicina molecolare e biotecnologie mediche
Ciclo di dottorato: 33
Coordinatore del Corso di dottorato:
Mallardo, MassimoUNSPECIFIED
Date: 14 July 2021
Number of Pages: 98
Keywords: STING, antigen presentation, knock-out, macrophages, STAT1
Settori scientifico-disciplinari del MIUR: Area 05 - Scienze biologiche > BIO/11 - Biologia molecolare
Area 05 - Scienze biologiche > BIO/13 - Biologia applicata
Date Deposited: 19 Jul 2021 11:03
Last Modified: 07 Jun 2023 11:25

Collection description

STimulator of INterferon Genes (STING) is a transmembrane ER resident protein involved in the interferon response to viral infection. Recent accumulating evidences show that the role of STING is not restricted to viral response but covers a broad range of processes. Here we assessed the role of STING in the MHC-I antigen presentation by generating mouse macrophages cell line, J774, STING KO. We observed an impaired OVA-derived SIINFEKL peptide presentation in STING KO cells. The defect is not caused by either uptake or processing of the ovalbumin. The analysis of the peptide loading complex showed an impaired gene expression of TAP1, TAP2 and TAPBP in STING KO though no differences in the protein expression were noticed. Co-IP assay upon OVA-treatment revealed no interaction between STING and TAP1. Cell surface levels of MHC-I were heavily decreased in STING KO macrophages. The mRNA expression of H2K1 heavy chain was not divergent between WT and KO whereas β2m light chain level was reduced in STING KO either at steady state and upon OVA treatment. Notably, STAT1 phosphorylation resulted impaired in KO upon OVA and LPS treatments. Moreover, the basal levels of STAT1 mRNA expression and protein were affected in the STING KO phenotype. Furthermore, OVA-induced STAT1 transcription was not observed in STING KO. We observed a reduction in CD11c cell surface levels in KO macrophages. In contrast, gene expression analysis revealed a basal higher level in STING KO and an OVA-induced increase. Finally, defects in Nf-κB activation and response to IFN-γ were observed in STING KO macrophages. Taken together these data confirm a role of STING in the antigen presentation that may occur either by regulating STAT1 signaling or by mediating the transport to the cell surface.


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