Mesenchymal stromal cells effectively limit house dust mite extract‐induced mixed granulocytic lung inflammation
Authors: Marlena Tynecka, Adrian Janucik, Agnieszka Tarasik, Arkadiusz Zbikowski, Magdalena Niemira, Agnieszka Kulczynska‐Przybik, Anna Zeller, Nino Stocker, Joanna Reszec‐Gielazyn, Barbara Mroczko, Adam Kretowski, Cezmi A. Akdis, Milena Sokolowska, Marcin Moniuszko, Andrzej Eljaszewicz
Journal: Allergy (2024)

Mesenchymal stromal cells (MSCs, also known as mesenchymal stem cells) have gained considerable interest due to their immunosuppressive properties and regenerative potential. In the vast majority of published papers, the beneficial effects of MSCs in asthma have been confirmed in experimental eosinophilic (T2-dependent) allergic airway inflammation in the OVA/alum-induced model, while their immunoregulatory activities in mixed-granulocytic inflammatory phenotypes remain not fully elucidated.1-4 Moreover, the majority of published reports utilize intraperitoneal or intravenous injection of bone marrow-derived MSCs.2-5 Therefore, we aimed to evaluate the effects of adipose tissue-derived MSC intranasal administration on experimental mixed granulocytic asthma. House dust mite (HDM) extract-induced experimental mixed-granulocytic asthma was induced in C57BL6 mice (Figures S1 and S2).6 MSCs were administrated intranasally on Day 6 (Figure 1A, a detailed description of the model and materials and methods can be found in the supplementary materials to this manuscript). First, we observed a significant reduction of lung leukocyte infiltration after administration of MSCs (Figure 1B). In addition, we found a substantial decrease in eosinophil numbers and a trend to decrease neutrophil counts within the lung (Figure 1C). MSCs' immunomodulatory potential depends on the local microenvironment in which proinflammatory stimuli induce anti-inflammatory properties of these cells.3, 7 To date, described mechanisms include (a) regulation of monocyte maturation and inhibition of macrophage polarization toward inflammatory cells (classically activated M1 cells); (b) promotion of antigen-presenting cell maturation toward tolerogenic cells; (c) regulation of CD4+ T helper cells and CD8+ cytotoxic T-cell proliferation and activation; (d) recruitment of regulatory T cells; (e) induction of functional plasticity of effector T cells; and (f) reduction of B-cell maturation and antibody production.3 To define potential mechanisms in which mixed granulocytic inflammation in the lung is regulated by MSCs, we performed a transcriptomic analysis of the lungs. First, we found distinct signatures of differentially expressed genes among the analyzed groups (Figure S3). We observed decreased expression of genes associated with eosinophil recruitment (Figure 1D), neutrophil recruitment (Figure 1E), and lymphocyte proliferation (Figure 1F). In addition, we observed changes in the expression of genes responsible for epithelial barrier function (tight junctions, Figure S4) and encoding chemotactic factors (Figure S5) after MSCs administration compared to untreated asthmatic mice. Uncontrolled prolonged airway inflammation damages the lung and triggers the healing processes, leading to mucus hypersecretion and subepithelial fibrosis, among others. Therefore, having found that MSCs effectively limit lung inflammation, we aimed to evaluate the effect on mucus production and subepithelial fibrosis. Surprisingly, we found no differences in mucus production after MSC transfer (Figure 1G); however, we observed a significant reduction of extracellular matrix deposition in the subepithelial area (Figure 1H). Moreover, we found changes in the expression level of proteolytic enzymes involved in extracellular matrix degradation, namely matrix metalloproteinases (MMPs, Figure S6A), a disintegrin and metalloproteinases (ADAMs, Figure S6B), and ADAMTSs (a disintegrin and metalloproteinases with thrombospondin motifs, Figure S6C). Next, we aimed to validate the results at the protein level (Figure 2). In contrast to tight junction gene expression (Figure S4), at the protein level, we observed a slight increase in the presence of ZO-1 in the lung epithelial cells but not occludin and claudin 3 (Figure 2A). In addition, we found that MSCs administration to the lung with mixed allergic inflammation does not change the levels of alarmins, namely interleukin (IL)-33 and IL-25 in bronchoalveolar lavage fluid (BALF). However, we observed differences in the heterogeneity of T effector cells among the analyzed groups (Figure 2C; for a detailed description of the results, please see supplementary data results and Figure S7). We observed a reduction in the frequency of putative Th1, Th17, and, surprisingly, Treg but not Th2 cells (Figure 2D). Finally, we observed decreased macrophage colony-stimulating factor (M-CSF) concentrations after MSCs, intranasal transfer while no differences were observed in granulocyte macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) levels (Figure 2E). Furthermore, MSCs administration to the lungs with mixed neutrophilic inflammation decreased CCL21 level in BALF, while did not affect CCL3, CCL5, CCL11, CCL22, CXCL2, CXCL5, CXCL10, and CXCL12 (Figure 2F,G). However, the CXCL16 level tend to increase after (Figure 2G). Taking together, we showed here that adipose tissue-derived MSCs are effective in the regulation of mixed granulocytic HDM-induced asthmatic inflammation by (i) limitation of leukocyte migration, (ii) reduction in subepithelial collagen deposition, (iii) restoration of ZO-1 epithelial expression, (iv) changes in T-cell heterogeneity accompanied by decreased effector T-cell frequency and reduced eosinophil and neutrophil counts, and (v) decrease in CCL21 level (a chemokine responsible for leukocyte tracking to secondary lymphoid organs). Further studies are needed to fully elucidate the effects of MSCs in non-T2-driven asthmatic inflammation, to assess the long-term consequences of MSCs transplantation, and their fate in this complex asthmatic lung microenvironment. Concept design: AE; data collection: MT, AJ, AT, AZb, AK-P, AZe, NS; analysis/interpretation of data: MT, AJ, MN, JR-G, BM, AK, CAA, MS, MM, AE; draft preparation/intellectual contribution: MT, AJ, CA, MS, MM, AE. All authors recognized Agnieszka Popielska MSc and the Center of Experimental Medicine employees for technical support. The publication was written during doctoral studies under the project no. POWR.03.02.00-00-I050/16 co-funded from European Union Funds, PO WER 2014–2020, and the Medical University of Bialystok statutory funding. MT was supported by the Foundation for Polish Science START 2023. MT reports National Science Centre (grant no. 2020/37/N/NZ5/04144), National Centre for Research and Development (POLTUR3/MT-REMOD/2/2019); AKP received a consultation and/or lecture honoraria from Roche company; BM reports consultation and/or lecture honoraria from Abbott, Wiener, Roche, Cormay, Biameditek, Biokom and TK Biotech companies. CA has received research grants from the Swiss National Science Foundation, European Union (EU CURE, EU Syn-Air-G), Novartis Research Institutes, (Basel, Switzerland), Stanford University (Redwood City, Calif), Seed Health (Boston, USA) and SciBase (Stockholm, Sweden); is the Co-Chair for EAACI Guidelines on Environmental Science in Allergic diseases and Asthma; Chair of the EAACI Epithelial Cell Biology Working Group is on the Advisory Boards of Sanofi/Regeneron (Bern, Switzerland, New York, USA), Stanford University Sean Parker Asthma Allergy Center (CA, USA), Novartis (Basel, Switzerland), Glaxo Smith Kline (Zurich, Switzerland), Bristol–Myers Squibb (New York, USA), Seed Health (Boston, USA) and SciBase (Stockholm, Sweden); and is the Editor-in-Chief of Allergy. MS reports research grants from Swiss National Science Foundation (nr 310030_189334/1), Novartis Foundation for Medical-Biological Research, GSK, and Stiftung vorm. Buendner Heilstaette Arosa; speaker's fee from AstraZeneca; voluntary positions in the European Academy of Allergy and Clinical Immunology (EAACI) as Executive Board member and Basic and Clinical Immunology Section Chair. MM reports personal payments from Astra Zeneca, GSK, Sanofi, Berlin-Chemie/Menarini, Chiesi, Lek-AM, Takeda, Teva, Novartis, CSL Behring, Celon and support for attending meetings from Chiesi, Astra Zeneca, GSK, Berlin-Chemie/Menarini. AE reports National Science Centre (grant no. 2020/37/N/NZ5/04144), National Centre for Research and Development (no. STRATEGMED2/269807/14/NCBR/2015), National Centre for Research and Development (POLTUR3/MT-REMOD/2/2019). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. All authors read and accepted the manuscript. The data that support the findings of this study are openly available in the Gene Expression Omnibus (GEO) repository at https://www.ncbi.nlm.nih.gov/gds, reference number GSE211620. Data S1. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.