Pulp stem cells with hepatocyte growth factor overexpression exhibit dual effects in rheumatoid arthritis

Dong et al. Stem Cell Research & Therapy (2020) 11:229 https://doi.org/10.1186/s13287-020-01747-y RESEARCH Open Access Pulp stem cells with hepatocyte growth factor overexpression exhibit dual effects in rheumatoid arthritis Xiwen Dong1,2, Fanxuan Kong1,2, Chao Liu3, Shiyun Dai1,2, Yuning Zhang1,2, Fengjun Xiao1,2, Huan Zhang4, Chu-Tse Wu1,2* and Hua Wang1,2* Abstract Background: To investigate the therapeutic effect of human dental pulp stem cells (DPSCs) transfected with adenovirus expressing hepatocyte growth factor (HGF) in a mouse model of collagen-induced arthritis (CIA). Methods: DPSCs were modified with Ad-HGF to produce HGF-overexpressing DPSCs, DPSCs-HGF. In experimental mouse CIA model, DPSCs-HGF and DPSCs-Null (modified with Ad-Null) were engrafted via intravenously after disease onset, which was determined by the presence of joint swelling. The therapeutic effects on joints were evaluated at 49 days after collagen injection by histopathological analysis and microcomputed tomography imaging. The inflammatory cytokines were analyzed both in sera and joints via MILLIPLEX kit and immunohistochemical staining, respectively, and the regulatory T cells (Tregs) were analyzed in peripheral blood by using flow cytometry. Furthermore, primary fibroblast-like synoviocytes were isolated, colony formation analysis and FACS were performed to evaluate the effect of HGF on the proliferation and cell cycle of FLSs. Western blot assay was carried out to clarify the signal pathway of HGF-cMet. Results: We found that without HGF modification, DPSC transfusion was helpful in controlling autoimmune status, local synovitis, and bone erosion after intravenous administration. However, HGF-modified DPSCs have dual role in rheumatoid arthritis (RA). In the early phase, HGF overexpression inhibited RA progression by its immunosuppressive effects, while in the late phase, HGF promoted synovitis by activating fibroblast-like synoviocytes to produce pathogenic IL-6, accelerating cell proliferation and inducing apoptosis resistance via phosphorylating the c-Met/Akt pathway. The overall effect of HGF modification attenuated the therapeutic effect of DPSCs. Conclusions: Our study provides a comprehensive evaluation of the therapeutic effect of DPSCs in the mouse model and a primary answer to the divergence of whether HGF is harmful or helpful in RA. Keywords: Dental pulp stem cells (DPSCs), Hepatocyte growth factor (HGF), Rheumatoid arthritis (RA), Cell therapy * Correspondence: ; 1 Department of Experimental Hematology, Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, People’s Republic of China Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Dong et al. Stem Cell Research & Therapy (2020) 11:229 Introduction RA is one of the most prevalent chronic autoimmune diseases, with an incidence of 0.5–1% in adults worldwide [1]. RA patients have both articular symptoms (pain, stiffness, swelling, etc.) and extra-articular manifestations (pleurisy, hydrothorax, anemia, etc.) as a result of autoimmune activation, prolonged inflammation, cartilage deterioration, and bone destruction [2]. Innate and adaptive immune cells as well as synovial cells participate in RA pathogenesis [3, 4]. Innate immune cells, such as macrophages and dendritic cells, facilitate the breakdown of immune tolerance. After that, adaptive immune cells (such as T or B lymphocytes) are activated, causing transformation of synovial cells to a more aggressive phenotype, which contributes to joint damage, and enhancing osteoclast activity, which induces osteolysis [3]. Disease-modifying anti-rheumatic drugs (DMARDs) and nonsteroidal anti-inflammatory drugs (NSAIDs) are the two major first-line drugs in RA treatment [1]. In terms of a treatment-to-target strategy, the prospects for most patients are now favorable, yet approximately 30% still do not respond to current drugs. Even when clinical remission is achieved, cartilage and bone erosion may stealthily persist resulting from ongoing autoimmune reaction [5]. Therefore, a promising strategy is to restore prolonged immune tolerance and to protect against local joint damage [6]. Recent evidence demonstrated that mesenchymal stem cells (MSCs) can reshape the immune response by altering both innate and adaptive immunity through direct cell-cell contact or secretion of modulatory factors. The immunomodulatory effects of MSCs have been extensively studied in MSCs from diverse tissue sources (such as bone marrow, adipose tissue, and dental pulp) [7]. As an important type of MSC, DPSCs are the first human dental stem cells extracted from dental pulp, which possess the capacity of immunomodulation, multilineage differentiation, and self-renewal [8]. DPSCs have been reported to possess stronger immune-regulatory effect than that of BMSCs [9, 10]. Conditioned medium from human deciduous DPSCs was reported to be helpful in anti-collagen type II antibody-induced arthritis. Moreover, in terms of their strong osteogenic capacity, DPSCs are an ideal cell source for bone regeneration. For instance, Kong et al. reported that DPSCs could prevent bone loss in ovariectomy-induced osteoporosis [11]. However, DPSCs’ prevention of bone erosion in RA needs to be studied. HGF is a multifunctional growth factor that plays a vital role in embryogenesis and organ development [12]. It could suppress acute and chronic inflammation after binding to its receptor c-Met. HGF/c-Met can modulate both innate and adaptive immune responses by stimulating anti-inflammatory cytokine secretion and inducing Page 2 of 15 tolerogenic dendritic cells, respectively [13]. It has been reported that HGF delivery by hydrogel could suppress antigen-induced T cell priming and enhance the Th2-type immune response to inhibit the development of CIA [14]. However, whether HGF modification could synergy DPSC therapeuti (...truncated)