Dr. Rabia Bilge Özgül Özdemir

Conference 2024 Live Talk

Talk Title

Investigation of the effect of Toll-like Receptor 4 and Fc-gamma Receptor III inhibition on macrophage activity

Authors and Affiliations

Rabia Bilge Özgül Özdemir1, Alper Tunga Özdemir2, Özgül Soysal Gündüz3, Kamil Vural5, Mustafa Öztatlıcı4, Özgür Akgül6

1- Department of Allergy and Clinical Immunology, Manisa City Hospital, Manisa, Turkey
2- Department of Medical Biochemistry, Merkezefendi State Hospital, Manisa, Turkey
3- Department of Internal Medicine, Division of Rheumatology, Manisa Celal Bayar University, Manisa, Turkey
4- Department of Histology and Embryology, Islam Science and Technology University, Gaziantep, Turkey
5- Department of Pharmacology, Manisa Celal Bayar University, Manisa, Turkey
6- Department of Physical Therapy and Rehabilitation, Division of Rheumatology, Manisa Celal Bayar University, Manisa, Turkey

Abstract

Background

Rheumatoid arthritis (RA) is an autoimmune disease in which joint involvement is prominent but affects all systems. Anti-Cyclic citrullinated peptide (Anti-CCP) autoantibodies, which have critical roles in the pathogenesis of RA, and their immune complexes (IC) with their antigens lead to the activation of immune cells such as macrophages, resulting in the secretion of inflammatory cytokines such as TNF-α, IL-1β and IL-6. It is possible. With this project, CCP molecules α-enolase, collagen-II and vimentin, which are commonly found in RA patients, and ICs from ACPAs found in patient serums were prepared and their effects on macrophages isolated from RA and control subjects were investigated comparatively.

Methods

PBMC isolation was performed by taking venous blood samples from 7 RA patients (4 females and 3 males) and 7 healthy subjects (4 females and 3 males). Human recombinant M-CSF and IFN-γ were used to obtain macrophages. Subsequently, experimental groups were formed in which TLR4 inhibitor, Fc receptor inhibitor and both of them were applied simultaneously to macrophages activated by LPS and ACPA-ICs, respectively. Changes in CD14, CD32, CD64, CD86, CD163 and CD200R expressions for macrophage phenotype changes were analyzed flow-cytometrically. Changes in TNF-α, IL-1β and IL-6 levels were determined by ELISA method.

Results

We showed that LPS administration produces a significant increase in all inflammatory cytokines as expected and this increase can be blocked with TLR4 inhibitor. We then showed that ACPA-ICs led to stronger activation than citrullinated peptides alone, and the increase in inhibitory macrophage markers such as CD163 and CD200R was significantly increased only in the double-blocking groups with TLR4 and Fc receptor inhibitors co-administered (p=0.037 and p<0.001, respectively). A similar situation was also valid for TNF-α, IL-1β and IL-6 expressions, the levels of these cytokines were significantly more suppressed in the double block group than in the other groups (p<0.001, p=0.018 and p<0.001, respectively). Conclusions Our project has revealed the first data that the dual-blocking approach may be a more effective approach than TLR4 or Fc receptor inhibition alone in effectively controlling both the macrophage phenotype and the inflammatory cytokines it secretes. In the light of the data we obtained from this project, we started to prepare projects for the development of recombinant chimeric TLR4-FcR inhibitor. After demonstrating the possible in-vitro efficacy of these chimeric molecules, we plan to conduct in-vivo and clinical phase studies. In this way, we aim to add a new one to the targeted alternative treatment approaches in the treatment of RA.