BACKGROUND: Mitochondrial transfer is becoming recognized as an important immunomodulatory mechanism used by mesenchymal stem cells (MSCs) to influence immune cells. While effects on T cells and macrophages have been documented, the influence on B cells remains unexplored. This study investigates the modulation of B lymphocyte fate by MSC-mediated mitochondrial transfer. METHODS: MSCs labelled with MitoTracker dyes or derived from mito::mKate2 transgenic mice were co-cultured with splenocytes. Flow cytometry assessed mitochondrial transfer, reactive oxygen species (ROS) levels, apoptosis and mitophagy. Glucose uptake was measured using the 2-NBDG assay. RNA sequencing analysed gene expression changes in CD19+ mitochondria recipients and nonrecipients. Pathway analysis identified affected processes. In an LPS-induced inflammation model, mito::mKate2 MSCs were administered, and B cells from different organs were analysed for mitochondrial uptake and phenotypic changes. MSC-derived mitochondria were also isolated to confirm uptake by FACS-sorted CD19+ cells. RESULTS: MSCs transferred mitochondria to CD19+ cells, though less than to other immune cells. Transfer correlated with ROS levels and mitophagy induction. Mitochondria were preferentially acquired by activated B cells, as indicated by increased CD69 expression and glycolytic activity. Bidirectional transfer occurred, with immune cells exchanging dysfunctional mitochondria for functional ones. CD19+ recipients exhibited increased viability, proliferation and altered gene expression, with upregulated cell division genes and downregulated antigen presentation genes. In vivo, mitochondrial acquisition reduced B cell activation and inflammatory cytokine production. Pre-sorted B cells also acquired isolated mitochondria, exhibiting a similar anti-inflammatory phenotype. CONCLUSIONS: These findings highlight mitochondrial trafficking as a key MSC-immune cell interaction mechanism with immunomodulatory therapeutic potential.

• Keywords
• B cell, immunoregulation, mesenchymal stem cell, metabolism, mitochondria,
• MeSH
• Lymphocyte Activation MeSH
• Antigens, CD19 metabolism   MeSH
• Apoptosis MeSH
• B-Lymphocytes * immunology   physiology   metabolism   MeSH
• Antigens, CD MeSH
• Antigens, Differentiation, T-Lymphocyte MeSH
• Coculture Techniques MeSH
• Lectins, C-Type MeSH
• Mesenchymal Stem Cells * physiology   MeSH
• Mitochondria * metabolism   physiology   MeSH
• Mitophagy MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Reactive Oxygen Species metabolism   MeSH
• Spleen cytology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antigens, CD19 MeSH
• Antigens, CD MeSH
• CD69 antigen MeSH Browser
• Antigens, Differentiation, T-Lymphocyte MeSH
• Lectins, C-Type MeSH
• Reactive Oxygen Species MeSH

It is becoming increasingly evident that selecting an optimal source of mesenchymal stromal cells (MSCs) is crucial for the successful outcome of MSC-based therapies. During the search for cells with potent regenerative properties, Sertoli cells (SCs) have been proven to modulate immune response in both in vitro and in vivo models. Based on morphological properties and expression of surface markers, it has been suggested that SCs could be a kind of MSCs, however, this hypothesis has not been fully confirmed. Therefore, we compared several parameters of MSCs and SCs, with the aim to evaluate the therapeutic potential of SCs in regenerative medicine. We showed that SCs successfully underwent osteogenic, chondrogenic and adipogenic differentiation and determined the expression profile of canonical MSC markers on the SC surface. Besides, SCs rescued T helper (Th) cells from undergoing apoptosis, promoted the anti-inflammatory phenotype of these cells, but did not regulate Th cell proliferation. MSCs impaired the Th17-mediated response; on the other hand, SCs suppressed the inflammatory polarisation in general. SCs induced M2 macrophage polarisation more effectively than MSCs. For the first time, we demonstrated here the ability of SCs to transfer mitochondria to immune cells. Our results indicate that SCs are a type of MSCs and modulate the reactivity of the immune system. Therefore, we suggest that SCs are promising candidates for application in regenerative medicine due to their anti-inflammatory and protective effects, especially in the therapies for diseases associated with testicular tissue inflammation.

• Keywords
• Mesenchymal stem cells. Sertoli cells. Immunomodulation. Mitochondrial transfer,
• MeSH
• Anti-Inflammatory Agents MeSH
• Immunity MeSH
• Humans MeSH
• Mesenchymal Stem Cells * MeSH
• Mitochondria MeSH
• Sertoli Cells * MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anti-Inflammatory Agents MeSH

BACKGROUND: Immunosuppressive cell-based therapy is a recent strategy for controlling Graft-versus-Host Disease (GvHD). Such cells ought to maintain their suppressive function in inflammatory conditions and in the presence of immunosuppressive agents currently used in allogeneic hematopoietic cell transplantation (allo-HCT). Moreover, these therapies should not diminish the benefits of allo-HCT, the Graft-versus-Leukemia (GvL) effect. We have previously reported on a novel subset of human monocyte-derived suppressor cells (HuMoSC) as a prospective approach for controlling GvHD.Objective. UNLABELLED: The objective of this study was to explore the therapeutic relevance of the HuMoSC in clinical conditions. METHODS: Immune regulatory functions of HuMoSC were assessed in inflammatory conditions and in the presence of immunosuppressants. The therapeutic efficiency of the association of HuMoSC with immunosuppressants was evaluated in an experimental model of GvHD induced by human PBMC in NOD/SCID/IL2-Rγc-/- (NSG) mice. UNLABELLED: Interestingly, the inhibitory functions of HuMoSC against T lymphocytes and their ability to polarize Treg are preserved, in vitro, in inflammatory environments and are not affected by immunosuppressive agents. In vivo, the association of HuMoSC-based treatment with an immunosuppressive drug showed a synergistic effect for controlling GvHD. Furthermore, HuMoSC control GvHD while preserving GvL effect in a xeno-GvHD conditioned mouse model with cell neoplasm (CAL-1). HuMoSC are generated according to good manufacturing practices (GMP) and we demonstrated that these cells tolerate long-term preservation with unaltered phenotype and function.Conclusion. UNLABELLED: HuMoSC-based therapy represents a promising approach for controlling GvHD and could be quickly implemented in clinical practice.

• Keywords
• Human monocyte-derived suppressor cells, graft-versus-host disease, graft-versus-leukemia effect, immunosuppressive drugs, inflammation, regulatory T cells,
• MeSH
• Leukemia * MeSH
• Leukocytes, Mononuclear MeSH
• Humans MeSH
• Monocytes MeSH
• Mice, Inbred NOD MeSH
• Mice, SCID MeSH
• Mice MeSH
• Graft vs Host Disease * prevention & control   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH