Dissecting paracrine effectors for mesenchymal stem cells

Preparation of poly(acrylic acid)/tricalcium phosphate nanoparticles scaffold: Characterization and releasing UC-MSCs derived exosomes for bone differentiation

Introduction

This study focused on preparing a multiscale three-dimensional (3D) scaffold using tricalcium phosphate nanoparticles (triCaPNPs) in a substrate of poly(acrylic acid) (PAA) polymer for controlled release of exosomes in bone tissue engineering.

Methods

A scaffold was fabricated with a material mixture containing acrylic acid (AA) monomer, N,N'-methylenebisacrylamide (MBAA), ammonium persulfate (APS), sodium bicarbonate (SBC), and triCaPNPs called composite scaffold (PAA/triCaPNPs) via cross-linking and freeze-drying methods. The synthesis process was easy and without complex multi-steps. Through mimicking the hybrid (organic-inorganic) structure of the bone matrix, we here chose triCaPNPs for incorporation into the PAA polymer. After assessing the physicochemical properties of the scaffold, the interaction of the scaffold with human umbilical cord mesenchymal stem cells (UC-MSCs) such as attachment, proliferation, and differentiation to osteoblast cells was evaluated. In addition, we used DiI-labeled exosomes to verify the exosome entrapment and release from the scaffold.

Results

The polymerization reaction of 3D scaffold was successful. Based on results of physicochemical properties, the presence of nanoparticles in the composite scaffold enhanced the mechanical stiffness, boosted the porosity with a larger pore size range, and offered better hydrophilicity, all of which would contribute to greater cell penetration, proliferation, and then better bone differentiation. In addition, our results indicated that our scaffold could take up and release exosomes, where the exosomes released from it could significantly enhance the osteogenic commitment of UC-MSCs.

Conclusion

The current research is the first study fabricating a multiscale scaffold using triCaPNPs in the substrate of PPA polymer using a cross-linker and freeze-drying process. This scaffold could mimic the nanoscale structure and chemical combination of native bone minerals. In addition, our results suggest that the PAA/triCaPNPs scaffold could be beneficial to achieve controlled exosome release for exosome-based therapy in bone tissue engineering.

Mesenchymal stromal cell-derived extracellular vesicles: novel approach in hematopoietic stem cell transplantation

Bone marrow mesenchymal stromal cells (MSCs) play a crucial role in the regulation of hematopoiesis. These cells affect the process through direct cell–cell contact, as well as releasing various trophic factors and extracellular vehicles (EVs) into the bone marrow microenvironment. MSC-derived EVs (MSC-EVs) are prominent intercellular communication tolls enriched with broad-spectrum bioactive factors such as proteins, cytokines, lipids, miRNAs, and siRNAs. They mimic some effects of MSCs by direct fusion with hematopoietic stem cells (HSC) membranes in the bone marrow (BM), thereby affecting HSC fate. MSC-EVs are attractive scope in cell-free therapy because of their unique capacity to repair BM tissue and regulate proliferation and differentiation of HSCs. These vesicles modulate the immune system responses and inhibit graft-versus-host disease following hematopoietic stem cell transplantation (HSCT). Recent studies have demonstrated that MSC-EVs play an influential role in the BM niches because of their unprecedented capacity to regulate HSC fate. Therefore, the existing paper intends to speculate upon the preconditioned MSC-EVs as a novel approach in HSCT.

PDLSCs Regulate Angiogenesis of Periodontal Ligaments via VEGF Transferred by Exosomes in Periodontitis

Abnormal angiogenesis is one of the significant features in periodontitis leading to progressive inflammation, but angiogenic changes of periodontal ligaments under inflammatory condition were rarely reported. Periodontal ligament stem cells (PDLSCs) were a kind of dental stem cells associated with vascularization. Here we investigated the alteration of angiogenesis of periodontal ligament in periodontitis, and revealed an exosome-mediated pathway to support the effect of PDLSCs on angiogenic improvement. Vascular specific marker CD31 and VEGFA were found to be highly expressed in periodontal ligaments of periodontitis. The VEGFA expression was up-regulated in inflamed PDLSCs compared to control, meanwhile the tube formation of HUVECs was improved when co-cultured with inflamed PDLSCs. Exosomes secretion of PDSLCs was augmented by inflammation, and promoted angiogenesis of HUVECs, whereas blocking secretion of exosomes led to degenerated angiogenesis of HUVECs. Exosome-trasferred VEGFA was proven to be the crucial communicator between PDLSCs and HUVECs. Inflammation inhibited miR-17-5p expression of PDLSCs and relieved its target VEGFA. However, overexpression of miR-17-5p blocked the pro-angiogenic ability of inflamed PDLSCs. In conclusion, the findings indicated that vascularization of periodontal ligaments was enhanced, and inflammatory micro-environment of periodontitis facilitated pro-angiogenesis of PDLSCs through regulating exosome-mediated transfer of VEGFA, which was targeted by miR-17-5p.

Potential role of stem cells in disease prevention based on a murine model of experimental necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating disease of newborns, and despite years of research, there is no known cure. The mortality rate of infants with NEC remains as high as 20%-30%. Babies who survive NEC frequently have long term complications including short gut syndrome, developmental delays and neurological sequelae. Unfortunately, despite much research over the past years, the precise pathogenesis of the disease is still not completely understood.

METHODS

Our laboratory has focused on identifying novel therapies to prevent the disease, including the use of stem cells (SC), heparin-binding epidermal growth factor-like growth factor (HB-EGF) and recently, stem cell derived-exosomes, a type of nanovesicle, to combat this illness.

RESULTS

We have outlined the major SC lines and data suggesting potential benefit as a curative or preventive approach for NEC as well as describing several new therapeutic strategies, including stem cell derived- exosomes and HB-EGF for decreasing the incidence and severity of this disease in rat models in our lab.

CONCLUSION

Overall, our lab has demonstrated that these different types of SC equivalently reduce the incidence and severity of NEC and equally preserve intestinal barrier function during NEC. We have previously demonstrated that AF-MSC can protect the intestines from intestinal injury and may therefore hold strong therapeutic potential for the prevention of NEC. Most recently, our work with stem cell derived-exosomes has shown them to be equivalent to their derived SC lines in decreasing the incidence of this disease.

Dental pulp stem cells: Novel cell-based and cell-free therapy for peripheral nerve repair

The regeneration of peripheral nerves comprises complicated steps involving a set of cellular and molecular events in distal nerve stumps with axonal sprouting and remyelination. Stem cell isolation and expansion for peripheral nerve repair (PNR) can be achieved using a wide diversity of prenatal and adult tissues, such as bone marrow or brain tissues. The ability to obtain stem cells for cell-based therapy (CBT) is limited due to donor site morbidity and the invasive nature of the harvesting process. Dental pulp stem cells (DPSCs) can be relatively and simply isolated from the dental pulps of permanent teeth, extracted for surgical or orthodontic reasons. DPSCs are of neural crest origin with an outstanding ability to differentiate into multiple cell lineages. They have better potential to differentiate into neural and glial cells than other stem cell sources through the expression and secretion of certain markers and a range of neurotropic factors; thus, they should be considered a good choice for PNR using CBT. In addition, these cells have paracrine effects through the secretion of neurotrophic growth factors and extracellular vesicles, which can enhance axonal growth and remyelination by decreasing the number of dying cells and activating local inhabitant stem cell populations, thereby revitalizing dormant or blocked cells, modulating the immune system and regulating inflammatory responses. The use of DPSC-derived secretomes holds great promise for controllable and manageable therapy for peripheral nerve injury. In this review, up-to-date information about the neurotrophic and neurogenic properties of DPSCs and their secretomes is provided.

A New Approach to Cerebral Palsy Treatment: Discussion of the Effective Components of Umbilical Cord Blood and its Mechanisms of Action

Cerebral palsy (CP) includes a group of persistent non-progressive disorders affecting movement, muscle tone, and/or posture. The total economic loss during the life-span of an individual with CP places a heavy financial burden on such patients and their families worldwide; however, a complete cure is still lacking. Umbilical cord blood (UCB)-based interventions are emerging as a scientifically plausible treatment and possible cure for CP. Stem cells have been used in many experimental CP animal models and achieved good results. Compared with other types of stem cells, those from UCB have advantages in terms of treatment safety and efficacy, ethics, non-neoplastic proliferation, accessibility, ease of preservation, and regulation of immune responses, based on findings in animal models and clinical trials. Currently, the use of UCB-based interventions for CP is limited as the components of UCB are complex and possess different therapeutic mechanisms. These can be categorized by three aspects: homing and neuroregeneration, trophic factor secretion, and neuroprotective effects. Our review summarizes the features of active components of UCB and their therapeutic mechanism of action. This review highlights current research findings and clinical evidence regarding UCB that contribute to treatment suggestions, inform decision-making for therapeutic interventions, and help to direct future research.

Interleukin 17 (IL-17)-Induced Mesenchymal Stem Cells Prolong the Survival of Allogeneic Skin Grafts

BACKGROUND Mesenchymal stem cells (MSCs) have the potential of self-renewal and multi-differentiation and have a wide application prospect in organ transplantation for the effect of inducing immune tolerance. It has found that interleukin 17 (IL-17) could enhance the inhibition effect of MSCs on T cell proliferation and increase the immunosuppressive effect of MSCs. In this study, we aimed to investigate the effect of IL-17-induced MSCs on allograft survival time after transplantation. MATERIAL AND METHODS BMSCs were characterized by differential staining. The allogenic skin transplantations were performed and the BMSCs pre-treated by IL-17 were injected. To assess the immunosuppressive function of IL-17-induced BMSCs, the morphology of the grafts, the homing ability of the BMSCs, and the survival time of the grafts were analyzed. RESULTS BMSCs from BALB/c have multidirectional differentiation potential to differentiate into osteogenic, chondrogenic, and adipogenic lineage cells. IL-17-induced BMSCs prolonged the survival time of allogeneic skin grafts dramatically. We found that there were more labeled MSCs in the skin grafts, and the Treg subpopulations percentage, IL-10, and TGF-β were significantly increased, while the IFN-γ level was decreased compared to the control group and MSCs group. In conclusion, IL-17 can enhance the homing ability of MSCs and regulate the immunosuppressive function of MSC. CONCLUSIONS Our data demonstrate that IL-17 plays the crucial role in MSC homing behaviors and promotes immunosuppression of MSCs during transplantation procedures, suggesting that IL-17-pre-treated MSCs have potential to prolong graft survival and reduce transplant rejection.

Bone marrow mesenchymal stem cells reduce ureteral stricture formation in a rat model via the paracrine effect of extracellular vesicles

With no effective therapy to prevent or treat ureteral stricture (US), a multifactorial fibrotic disease after iatrogenic injury of the ureter, the need for new therapies is urgent. Mesenchymal stem cells (MSCs) have been widely studied for treating tissue defects and excessive fibrosis, and recent studies established that one of the main therapeutic vectors of MSCs is comprised in their secretome and represented by extracellular vesicles (EVs). Thus, we have determined to explore the specific role of MSCs‐derived EVs (MSC‐EVs) treatment in a pre‐clinical model of US. The results firstly showed that either a bolus dose of MSCs or a bolus dose of MSC‐EVs (administration via renal‐arterial) significantly ameliorated ureteral fibrosis and recuperated ureter morphological development in a US rat model. We confirmed our observations through MSCs or MSC‐EVs treatment alleviated hydronephrosis, less renal dysfunction and blunted transforming growth factor‐β1 induced fibration. Due to MSC‐EVs are the equivalent dose of MSCs, and similar curative effects of transplantation of MSCs and MSC‐EVs were observed, we speculated the curative effect of MSCs in treating US might on account of the release of EVs through paracrine mechanisms. Our study demonstrated an innovative strategy to counteract ureteral stricture formation in a rat model of US.

The Effect of Mesenchymal Stem Cell-Derived Microvesicles on Erythroid Differentiation of Umbilical Cord Blood-Derived CD34+ Cells

Purpose: Mesenchymal stem cells (MSCs) play an important role in the proliferation and differentiation of hematopoietic stem cells (HSCs) in the bone marrow via cell-to-cell contact, as well as secretion of cytokines and microvesicles (MVs). In this study, we investigated the effect of mesenchymal stem cell-derived microvesicles (MSC-MVs) on erythroid differentiation of umbilical cord blood-derived CD34⁺ cells.

Methods: In this descriptive study, CD34⁺ cells were cultured with mixture of SCF (10 ng/ml) and rhEPO (5 U/ml) cytokines in complete IMDM medium as positive control group. Then, in MV1- and MV2-groups, microvesicles at 10 and 20 µg/ml concentration were added. After 72 hours, erythroid specific markers (CD71 and CD235a) and genes (HBG1, GATA1, FOG1 and NFE2) were assessed by flow cytometry and qRT-PCR, respectively.

Results: The expression of specific markers of the erythroid lineages (CD71 and GPA) in the presence of different concentration of microvesicles were lower than that of the control group (P<0.001). Also, the expression of specific genes of the erythroid lineages (NFE2, FOG1, GATA1, and HBG1) was investigated in comparison to the internal control (GAPDH). Among all of them, HBG1 and FOG1 genes were significantly decreased to the control group (P<0.0001) but GATA1 and NFE2 gene expressions was not significant.

Conclusion: The results of this study showed that MSC-MVs decrease the erythroid differentiation of umbilical cord blood-derived CD34⁺ cells. Therefore, MSC-MVs play a key role in the regulation of normal erythropoiesis.

Mesenchymal Stem Cell Microvesicles Restore Protein Permeability Across Primary Cultures of Injured Human Lung Microvascular Endothelial Cells

Our previous study demonstrated that mesenchymal stem cell (MSC) microvesicles (MV) reduced lung inflammation, protein permeability, and pulmonary edema in endotoxin-induced acute lung injury in mice. However, the underlying mechanisms for restoring lung protein permeability were not fully understood. In this current study, we hypothesized that MSC MV would restore protein permeability across injured human lung microvascular endothelial cells (HLMVEC) in part through the transfer of angiopoietin-1 (Ang1) mRNA to the injured endothelium. A transwell coculture system was used to study the effect of MSC MV on protein permeability across HLMVECs injured by cytomix, a mixture of IL-1β, TNF-α, and IFN-γ (50 ng/ml). Our result showed that cytomix significantly increased permeability to FITC-dextran (70 kDa) across HLMVECs over 24 hours. Administration of MSC MVs restored this permeability in a dose dependent manner, which was associated with an increase in Ang1 mRNA and protein secretion in the injured endothelium. This beneficial effect was diminished when MSC MV was pretreated with an anti-CD44 antibody, suggesting that internalization of MV into the HLMVEC was required for the therapeutic effect. Fluorescent microscopy showed that MSC MV largely prevented the reorganization of cytoskeleton protein F-actin into "actin stress fiber" and restored the location of the tight junction protein ZO-1 and adherens junction protein VE-cadherin in injured HLMVECs. Ang1 siRNA pretreatment of MSC MV prior to administration to injured HLMVECs eliminated the therapeutic effect of MV. In summary, MSC MVs restored protein permeability across HLMVEC in part by increasing Ang1 secretion by injured HLMVEC. Stem Cells Translational Medicine 2018;7:615-624.

Stem cell therapy in necrotizing enterocolitis: Current state and future directions

Stem cell therapy is a promising treatment modality for necrotizing enterocolitis. Among the many promising stem cells identified to date, it is likely that mesenchymal stem cells will be the most useful and practical cell-based therapies for this condition. Using acellular components such as exosomes or other paracrine mediators are promising as well. Multiple mechanisms are likely at play in the positive effects provided by these cells, and further research is underway to further elucidate these effects.

Efficient ultrafiltration-based protocol to deplete extracellular vesicles from fetal bovine serum

Fetal bovine serum (FBS) is the most commonly used supplement in studies involving cell-culture experiments. However, FBS contains large numbers of bovine extracellular vesicles (EVs), which hamper the analyses of secreted EVs from the cell type of preference and, thus, also the downstream analyses. Therefore, a prior elimination of EVs from FBS is crucial. However, the current methods of EV depletion by ultracentrifugation are cumbersome and the commercial alternatives expensive. In this study, our aim was to develop a protocol to completely deplete EVs from FBS, which may have wide applicability in cell-culture applications. We investigated different EV-depleted FBS prepared by our novel ultrafiltration-based protocol, by conventionally used overnight ultracentrifugation, or commercially available depleted FBS, and compared them with regular FBS. All sera were characterized by nanoparticle tracking analysis, electron microscopy, Western blotting and RNA quantification. Next, adipose-tissue mesenchymal stem cells (AT-MSCs) and cancer cells were grown in the media supplemented with the three different EV-depleted FBS and compared with cells grown in regular FBS media to assess the effects on cell proliferation, stress, differentiation and EV production. The novel ultrafiltration-based protocol depleted EVs from FBS clearly more efficiently than ultracentrifugation and commercial methods. Cell proliferation, stress, differentiation and EV production of AT-MSCs and cancer cell lines were similarly maintained in all three EV-depleted FBS media up to 96 h. In summary, our ultrafiltration protocol efficiently depletes EVs, is easy to use and maintains cell growth and metabolism. Since the method is also cost-effective and easy to standardize, it could be used in a wide range of cell-culture applications helping to increase comparability of EV research results between laboratories.

Stem cell extracellular vesicles and kidney injury

Extracellular vesicles (EVs) appear as a new promising cell-free therapy for acute and chronic renal diseases. EVs retain characteristics of the cell of origin and those derived from stem cells may mimic their regenerative properties per se. In fact, EVs contain many active molecules such as proteins and RNA species that act on target cells through different mechanisms, stimulating proliferation and angiogenesis and reducing apoptosis and inflammation. There are several reports that demonstrate a general regenerative potential of EVs derived from mesenchymal stromal cells (MSCs) of different sources in kidney injury models. In addition, a promising new approach is the use of EVs in the graft perfusion solution for kidney conditioning before transplant. Here we summarize the application of EVs released by stem cells in preclinical models of acute and chronic renal damage, comparing animal models, use of EVs of different cell origin and of their sub-fractions, doses, route of administration and efficacy of treatment.

Renal Regenerative Potential of Different Extracellular Vesicle Populations Derived from Bone Marrow Mesenchymal Stromal Cells

Extracellular vesicles (EVs) derived from human bone marrow mesenchymal stromal cells (MSCs) promote the regeneration of kidneys in different animal models of acute kidney injury (AKI) in a manner comparable with the cells of origin. However, due to the heterogeneity observed in the EVs isolated from MSCs, it is unclear which population is responsible for the proregenerative effects. We therefore evaluated the effect of various EV populations separated by differential ultracentrifugation (10K population enriched with microvesicles and 100K population enriched with exosomes) on AKI recovery. Only the exosomal-enriched population induced an improvement of renal function and morphology comparable with that of the total EV population. Interestingly, the 100K EVs exerted a proproliferative effect on murine tubular epithelial cells, both in vitro and in vivo. Analysis of the molecular content from the different EV populations revealed a distinct profile. The 100K population, for instance, was enriched in specific mRNAs (CCNB1, CDK8, CDC6) reported to influence cell cycle entry and progression; miRNAs involved in regulating proliferative/antiapoptotic pathways and growth factors (hepatocyte growth factor and insulin-like growth factor-1) that could explain the effect of renal tubular cell proliferation. On the other hand, the EV population enriched in microvesicles (10K) was unable to induce renal regeneration and had a molecular profile with lower expression of proproliferative molecules. In conclusion, the different molecular composition of exosome- and microvesicle-enriched populations may explain the regenerative effect of EVs observed in AKI.

Mesenchymal Stem Cell-Derived Exosomes: New Opportunity in Cell-Free Therapy

Mesenchymal stromal/stem cells (MSCs) are involved in tissue homeostasis through direct cell-to-cell interaction, as well as secretion of soluble factors. Exosomes are the sort of soluble biological mediators that obtained from MSCs cultured media in vitro. MSC-derived exosomes (MSC-DEs) which produced under physiological or pathological conditions are central mediators of intercellular communications by conveying proteins, lipids, mRNAs, siRNA, ribosomal RNAs and miRNAs to the neighbor or distant cells. MSC-DEs have been tested in various disease models, and the results have revealed that their functions are similar to those of MSCs. They have the supportive functions in organisms such as repairing tissue damages, suppressing inflammatory responses, and modulating the immune system. MSC-DEs are of great interest in the scope of regenerative medicine because of their unique capacity to the regeneration of the damaged tissues, and the present paper aims to introduce MSC-DEs as a novel hope in cell-free therapy.

Obesity reduces the pro-angiogenic potential of adipose tissue stem cell-derived extracellular vesicles (EVs) by impairing miR-126 content: impact on clinical applications

BACKGROUND/OBJECTIVES

Soluble factors and cell-derived extracellular vesicles (EVs) are crucial tissue repair mediators in cell-based therapy. In the present study, we investigate the therapeutic impact of EVs released by adipose tissue-derived stem cells (ASCs) recovered from obese subjects' visceral and subcutaneous tissues.

METHODS

ASCs were recovered from 10 obese (oASCs) and 6 non-obese (nASCs) participants and characterized. In selected experiments, nASCs and oASCs were cultured with palmitic acid (PA) or high glucose (HG), respectively. EVs from obese (oEVs) and non-obese (nEVs) subjects' visceral and subcutaneous ASCs were collected after ultracentrifugation and analyzed for their cargo: microRNA-126 (miR-126), vascular endothelial growth factor (VEGF), and matrix metalloproteinase 2 (MMP-2), and for their biological effects on endothelial cells (ECs). Western blotting analysis and loss- and gain-of function experiments were performed.

RESULTS

oEVs show impaired angiogenic potential compared with nEVs. This effect depends on EV cargo: reduced content of VEGF, MMP-2 and, more importantly, miR-126. We demonstrate, using gain- and loss-of-function experiments, that this reduced miR-126 content leads to Spred1 upregulation and the inhibition of the extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase pathway in ECs. We also show that PA treatment of nASCs translates into the release of EVs that recapitulate oEV cargo. Moreover, HG treatment of oASCs further reduces miR-126 EV content and EV-mediated in vitro angiogenesis. Finally, impaired pro-angiogenic potential is also detected in EVs released from obese subcutaneous adipose tissue-derived ASCs.

CONCLUSIONS

These results indicate that obesity impacts on EV pro-angiogenic potential and may raise concerns about the use of adipose tissue-derived EVs in cell-based therapy in the obese setting.

Influence of erythropoietin on microvesicles derived from mesenchymal stem cells protecting renal function of chronic kidney disease

Introduction

Mesenchymal stem cells (MSCs) play a central role in the remediation of cell and tissue damage. Erythropoietin (EPO) may enhance the beneficial influence of MSCs during recovery from tissue and organ injuries. Microvesicles (MVs) released from MSCs contribute to the restoration of kidney damage. We studied the influence of EPO on MVs derived from MSCs, and the protective effects of these factors in subjects with chronic kidney disease (CKD).

Methods

The MVs derived from untreated MSCs (MSC-MVs) or from MSCs incubated in different concentrations of EPO (1, 10, 100, and 500 IU/ml EPO-MVs) were used to treat renal injury of unilateral ureteral obstruction (UUO) in vivo, and transforming growth factor-β1 (TGF-β1)-induced fibrosis in a human renal proximal tubular epithelial (HK2) cell line in vitro. Western blot and reverse transcription polymerase chain reaction (RT-PCR) analyses were used to evaluate the expression of epithelial and mesenchymal markers in the renal tissue and HK2 cells. Flow cytometry was used to assess apoptosis within the HK2 cells, and microRNA (miRNA) microarray assays were used to determine the expression profiles of miRNA in the MSC-MVs and EPO-MVs.

Results

Compared to MSC-MVs (untreated), there was a significant increase in the number of EPO-MVs derived from MSCs treated with 1–100 IU/ml EPO, and these EPO-MVs had a greater benefit in UUO mice on days 7 and 14. Moreover, the EPO-MVs had a better restorative effect following TGF-β1-induced fibrosis in HK2 cells at 24 h and 48 h. The flow cytometry results revealed that both types of MVs, especially EPO-MVs, play an important anti-apoptotic role in HK2 cells treated with TGF-β1. The miRNA profiles of the MVs revealed that EPO-MVs changed 212 miRNAs (fold-change ≥ 1.5), including miR-299, miR-499, miR-302, and miRNA-200, and that 70.28 % of these changes involved upregulation. The changed miRNA in EPO-MVs may have contributed to their enhanced protective effects following renal injury compared to MSC-MVs.

Conclusions

There was a dose-dependent increase in the level of EPO-MVs within the range of 1–100 IU/ml EPO. Although both MSC-MVs and EPO-MVs protect the kidney from fibrosis-related damage, there is a superior effect of EPO-MVs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0095-0) contains supplementary material, which is available to authorized users.

Melatonin pretreatment of human adipose tissue-derived mesenchymal stromal cells enhances their prosurvival and protective effects on human kidney cells

The efficacy of cell therapy for many diseases can be limited by the poor survival of implanted cells in an environment of tissue injury. Melatonin has been reported to have antioxidative and antiapoptotic effects. Adipose tissue-derived mesenchymal stromal cells (ASCs), cells easily obtained in high amounts and with minimal discomfort, have shown great promise in cell therapy applications, such as in acute kidney injury. We hypothesized that melatonin pretreatment of human ASCs (hASCs) would improve their renoprotective and prosurvival effects. We therefore investigated the action of melatonin on hASCs, as well as the effect of the resulting hASCs-conditioned media (CM) on human kidney cells exposed to oxidative and apoptotic injury-provoking doses of cisplatin. Our results demonstrated that pretreatment of hASCs with melatonin, 100 μM for 3 h, significantly increased their proliferation and their expression of prosurvival P-Erk1/2 and P-Akt, and of antioxidative enzymes catalase and heme oxygenase (HO)-1. In addition, the CM from hASCs pretreated with melatonin provoked a significantly higher proliferation and migration of HK-2 human kidney epithelial cells. Furthermore, this CM exerted significantly higher prosurvival and antiapoptotic actions on HK-2 cells exposed to cisplatin in vitro. Western blot analysis showed higher expression of P-Erk1/2, Bcl-2, SOD-1, and HO-1 in the HK-2 cells exposed to cisplatin in the presence of CM from melatonin-pretreated hASCs. In sum, our study revealed that in vitro pretreatment of hASCs with melatonin may significantly enhance their survival and their therapeutic effectiveness on injured tissue.