Small molecule inhibitors of the Fcγ receptor-dependent autoantibody-induced granulocyte activation

Abstract: Bullous pemphigoid (BP) and epidermolysis bullosa acquisita (EBA) are major subepidermal autoimmune blistering diseases, which are associated with antibodies against BP180 (type XVII collagen)/BP230 and type VII collagen, respectively. BP180, BP230 and type VII collagen are basement membrane components which promote adhesion at the dermal-epidermal junction. Immune complexes composed of IgG antibodies and BP180/BP230 or type VII collagen activate Fcγ-receptors (FcγRs) that induce signaling pathways leading to cellular cytotoxity via granulocyte-mediated tissue damage and release of reactive oxygen species (ROS). While a great number of small molecule inhibitors of these pathways have been tested in ex vivo and in vivo assays and are currently undergoing clinical trials for oncologic indications, their application in autoimmune diseases such as BP and EBA has received little attention so far. The current study addresses the potential inhibitory effect of 8 small molecule inhibitors (dasatinib, wortmannin, NSC 23766, EHT 1864, U0126, SB203580, PIK-93 and hesperadin) on FcγR-dependent granulocyte-mediated dermal-epidermal separation (DES) in previously established ex vivo assays. In a first set of experiments, the abilitiy of the inhibitors to prevent DES after injection into cryosections of neonatal human foreskin previously incubated with BP patient sera was addressed using cryosection assay. Furthermore, to assess the contribution of ROS generation by leucocytes upon contact with BP180 immune complexes to the occuring tissue damage, a ROS luminol assay was performed. Inhibition of the ROS production and tissue damage in the cryosection assay for the Src family kinase inhibitor dasatinib, the Aurora B inhibitor hesperadin, the MEK1/2 inhibitor U0126 and the PI3K inhibitor PIK-93 fully correlated and seemed to be dose-dependent. The Rac family small GTPases inhibitor EHT1864 completely inhibited ROS production while only 25% DES inhibition was detected in the cryosection experiments. Surprisingly, concentrations of 50 μM or even lower caused complete DES inhibition. Rac GTPase inhibitor NSC23766 did not show any inhibitory effect in the ROS production assay, while clear inhibition was detected in the cryosection assay. Interestingly, we observed a clear dose-dependency in the cryosection assay with the MAP kinase inhibitor SB203580, but increasing concentrations of the inhibitor rather enhanced ROS production. Finally, we observed a complete inhibition of ROS production by any of the tested concentrations of the PI3K inhibitor wortmannin, although DES and its gradual inhibition were seen in the cryosection assay. These results provide a mechanistic insight into the pathology of BP, EBA and of FcγR-mediated autoimmiune diseases in general and suggest new therapeutic strategies for the future. Recently developed animal models of EBA and BP should further facilitate reliable preclinical testing

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Albert-Ludwigs-Universität Freiburg, Dissertation, 2018

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2018
• Urheber: Shimanovich, Maria
• Beteiligte Personen und Organisationen: Sitaru, Cassian ; Klinik für Dermatologie und Venerologie ; Albert-Ludwigs-Universität Freiburg. Medizinische Fakultät ; Albert-Ludwigs-Universität Freiburg

Weitere Informationen

• DOI: 10.6094/UNIFR/15176
• URN: urn:nbn:de:bsz:25-freidok-151762
• Rechteinformation: Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 14.08.2025, 11:02 MESZ