Abstract: Neutrophil extracellular trap (NET) are thin and long web-like structures composed of DNA and antimicrobial proteins released by activated polymorphonuclear neutrophils (PMN) as part of the innate immune response. Adipose-derived stem cells (ADSCs) represent an accessible, abundant and minimal invasive source of mesenchymal stem cells (MSCs), with high regenerative potential, immunomodulatory and anti-inflammatory properties. Although recognized immunomodulatory properties of ADSCs, their interaction with PMN and their role on NET formation remains poorly characterized. The present study aimed to evaluate the effects of equine ADSCs on NET formation by equine PMN. Equine ADSCs were isolated from two different sources of adipose tissue, subcutaneous and retroperitoneal adipose stores. Equine PMN were isolated from peripheral blood with a discontinuous density gradient and stimulated with phorbol 12-myristate 13-acetate (PMA) to induce NET release as positive control. Scanning electron microscopy (SEM) and immunofluorescence microscopy (IFM) analyses were performed to assess NET release by equine PMN co-cultured with ADSCs. IFM-NET quantification revealed a significant NET decrease for PMN co-cultured with ADSCs and PMA. Furthermore, extracellular DNA quantification showed that inhibition of equine NET is dependent on the ADSCs to PMN ratio, for PMA and ionomycin stimulated PMN. Moreover, our findings unveil no modulation of reactive oxygen species (ROS) production by equine PMN when co-cultured with ADSCs. In summary, our results provide evidence of ADSCs on equine PMN, particularly in their capacity to attenuate NET formation and release. These results support the potential role of ADSCs on host innate immune response and thereby maintaining immune homeostasis. Further investigation is needed to better understand the specific molecular pathways involved in NETosis via ADSCs.
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
Overview
This study investigated how stem cells derived from horse fat tissue (adipose-derived stem cells or ADSCs) influence the formation of neutrophil extracellular traps (NETs) released by immune cells called polymorphonuclear neutrophils (PMNs).
The research found that these stem cells can reduce NET formation, suggesting a role in modulating innate immune responses and inflammation in horses.
Background
Neutrophil Extracellular Traps (NETs): NETs are web-like DNA structures mixed with antimicrobial proteins that PMNs release when activated, helping to trap and neutralize pathogens as part of the innate immune system.
Adipose-Derived Stem Cells (ADSCs): These are mesenchymal stem cells sourced from fat tissue, known for their regenerative abilities, immunomodulatory effects, and anti-inflammatory properties.
Despite known immune effects of ADSCs, their interaction with PMNs and impact on NET formation had been unclear before this study.
Research Objectives
To evaluate the effects of equine ADSCs on NET formation by equine PMNs in vitro.
To compare ADSCs derived from two fat tissue sources: subcutaneous and retroperitoneal adipose tissue.
To determine whether the presence of ADSCs affects reactive oxygen species (ROS) production by PMNs, which are involved in NET formation.
Methods
Isolation of Cells: ADSCs were isolated from two types of horse fat tissue; PMNs were isolated from peripheral horse blood using density gradient separation.
NET Induction: PMNs were stimulated using phorbol 12-myristate 13-acetate (PMA) and ionomycin to induce NET formation.
Co-Culture Experiments: PMNs were co-cultured with ADSCs to observe effects on NET release.
Visualization Techniques: Scanning electron microscopy (SEM) and immunofluorescence microscopy (IFM) were used to visualize and quantify NET release.
Extracellular DNA Quantification: Used as a measure of NET abundance, with analyses performed at different ADSC to PMN ratios.
ROS Measurement: Investigated to see if ADSCs impacted PMN oxidative burst, an important step in NETosis.
Key Findings
When equine PMNs were co-cultured with ADSCs and stimulated with PMA, the amount of NETs released was significantly reduced, indicating that ADSCs suppress NET formation.
The reduction in NET release was dependent on the ratio of ADSCs to PMNs, showing that higher numbers of ADSCs more effectively inhibited NET production.
This inhibitory effect was observed with both PMA- and ionomycin-stimulated PMNs.
No significant change was detected in the production of reactive oxygen species (ROS) by PMNs in the presence of ADSCs, suggesting ADSCs reduce NET release through mechanisms other than affecting oxidative burst.
Conclusions and Implications
Equine ADSCs have the ability to attenuate NET formation by PMNs, indicating they can modulate innate immune responses and potentially reduce excessive inflammation.
This immunomodulatory interaction highlights the therapeutic potential of ADSCs in managing immune system-related conditions in horses, especially where NETs may contribute to inflammation or tissue damage.
Understanding the molecular pathways by which ADSCs inhibit NETosis could reveal novel targets for controlling immune responses and improving regenerative therapies.
Further research is needed to dissect the exact biochemical and molecular mechanisms involved in ADSC-mediated NET regulation.
Cite This Article
APA
Salinas-Varas C, Espinosa G, Muñoz-Caro T, Conejeros I, Gärtner U, Fey K, Arnhold S, Taubert A, Hermosilla C.
(2025).
Equine adipose-derived stem cells modulate in vitro neutrophil extracellular trap release by polymorphonuclear neutrophils.
Front Vet Sci, 12, 1685757.
https://doi.org/10.3389/fvets.2025.1685757
Institute of Parasitology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Espinosa, Gabriel
Institute of Parasitology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Muñoz-Caro, Tamara
Escuela de Medicina Veterinaria, Facultad de Medicina Veterinaria y Recursos Naturales, Universidad Santo Tomás, Talca, Chile.
Conejeros, Iván
Institute of Parasitology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Gärtner, Ulrich
Institute of Anatomy and Cell Biology, Justus Liebig University Giessen, Giessen, Germany.
Fey, Kerstin
Equine Clinic, Internal Medicine, Justus Liebig University Giessen, Giessen, Germany.
Arnhold, Stefan
Institute of Veterinary Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Taubert, Anja
Institute of Parasitology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Hermosilla, Carlos
Institute of Parasitology, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany.
Conflict of Interest Statement
The 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.
References
This article includes 56 references
Ullah I, Subbarao RB, Rho GJ. Human mesenchymal stem cells - current trends and future prospective.. Biosci Rep (2015) 35:e00191.
Ferreira-Baptista C, Ferreira R, Fernandes MH, Gomes PS, Colaço B. Influence of the anatomical site on adipose tissue-derived stromal cells’ biological profile and osteogenic potential in companion animals.. Vet Sci (2023) 10:673.
Zhang J, Liu Y, Chen Y, Yuan L, Liu H, Wang J. Adipose-derived stem cells: current applications and future directions in the regeneration of multiple tissues.. Stem Cells Int (2020) 2020:1–26.
Chen B, Chen Z, He M, Zhang L, Yang L, Wei L. Recent advances in the role of mesenchymal stem cells as modulators in autoinflammatory diseases.. Front Immunol (2024) 15:1525380.
Kangari P, Talaei-Khozani T, Razeghian-Jahromi I, Razmkhah M. Mesenchymal stem cells: amazing remedies for bone and cartilage defects.. Stem Cell Res Ther (2020) 11:492.
Lv Z, Cai X, Bian Y, Wei Z, Zhu W, Zhao X. Advances in mesenchymal stem cell therapy for osteoarthritis: from preclinical and clinical perspectives.. Bioengineering (2023) 10:195.
Shi X, Chen Q, Wang F. Mesenchymal stem cells for the treatment of ulcerative colitis: a systematic review and meta-analysis of experimental and clinical studies.. Stem Cell Res Ther (2019) 10:266.
Yuan Z, Jiang D, Yang M, Tao J, Hu X, Yang X. Emerging roles of macrophage polarization in osteoarthritis: mechanisms and therapeutic strategies. Orthop Surg (2024) 16:532–50.
De Oliveira S, Rosowski EE, Huttenlocher A. Neutrophil migration in infection and wound repair: going forward in reverse. Nat Rev Immunol (2016) 16:378–91.
Zaripova LN, Midgley A, Christmas SE, Beresford MW, Pain C, Baildam EM. Mesenchymal stem cells in the pathogenesis and therapy of autoimmune and autoinflammatory diseases. Int J Mol Sci (2023) 24:16040.
Feng B, Feng X, Yu Y, Xu H, Ye Q, Hu R. Mesenchymal stem cells shift the pro-inflammatory phenotype of neutrophils to ameliorate acute lung injury. Stem Cell Res Ther (2023) 14:197.
Joel MDM, Yuan J, Wang J, Yan Y, Qian H, Zhang X. MSC: immunoregulatory effects, roles on neutrophils and evolving clinical potentials. Am J Transl Res (2019) 11:3890–904.
Taghavi-Farahabadi M, Mahmoudi M, Rezaei N, Hashemi SM. Wharton’s jelly mesenchymal stem cells exosomes and conditioned media increased neutrophil lifespan and phagocytosis capacity. Immunol Investig (2021) 50:1042–57.
Mahmoudi M, Taghavi-Farahabadi M, Namaki S, Baghaei K, Rayzan E, Rezaei N. Exosomes derived from mesenchymal stem cells improved function and survival of neutrophils from severe congenital neutropenia patients in vitro. Hum Immunol (2019) 80:990–8.
Jiang D, Muschhammer J, Qi Y, Kügler A, de Vries JC, Saffarzadeh M. Suppression of neutrophil-mediated tissue damage—a novel skill of mesenchymal stem cells. Stem Cells (2016) 34:2393–406.
Rodrigues M, Turner O, Stolz D, Griffith LG, Wells A. Production of reactive oxygen species by multipotent stromal cells/mesenchymal stem cells upon exposure to Fas ligand. Cell Transplant (2012) 21:2171–87.
Franck T, Ceusters J, Graide H, Mouithys-Mickalad A, Serteyn D. Muscle derived mesenchymal stem cells inhibit the activity of the free and the neutrophil extracellular trap (NET)-bond myeloperoxidase. Cells (2021) 10:3486.
Salami F, Tavassoli A, Mehrzad J, Parham A. Immunomodulatory effects of mesenchymal stem cells on leukocytes with emphasis on neutrophils. Immunobiology (2018) 223:786–91.
Wang LT, Lee W, Liu KJ, Sytwu HK, Yen ML, Yen BL. Mesenchymal stromal/stem cells know best: the remarkable complexities of its interactions with Polymorphonuclear neutrophils. Stem Cells (2024) 42:403–15.
Mumaw JL, Schmiedt CW, Breidling S, Sigmund A, Norton NA, Thoreson M. Feline mesenchymal stem cells and supernatant inhibit reactive oxygen species production in cultured feline neutrophils. Res Vet Sci (2015) 103:60–9.
Müller L, Tunger A, Wobus M, Von Bonin M, Towers R, Bornhäuser M. Immunomodulatory properties of mesenchymal stromal cells: an update. Front Cell Dev Biol (2021) 9:637725.
Conejeros I, Velásquez ZD, Grob D, Zhou E, Salecker H, Hermosilla C. Histone H2A and bovine neutrophil extracellular traps induce damage of Besnoitia besnoiti-infected host endothelial cells but fail to affect Total parasite proliferation. Biology (2019) 8:78.
Islam MM, Takeyama N. Role of neutrophil extracellular traps in health and disease pathophysiology: recent insights and advances. Int J Mol Sci (2023) 24:15805.
Retter A, Singer M, Annane D. “The NET effect”: neutrophil extracellular traps—a potential key component of the dysregulated host immune response in sepsis. Crit Care (2025) 29:59.