MSC-derived exosomes protect auditory hair cells from neomycin-induced damage via autophagy regulation

Background Sensorineural hearing loss (SNHL) poses a major threat to both physical and mental health; however, there is still a lack of effective drugs to treat the disease. Recently, novel biological therapies, such as mesenchymal stem cells (MSCs) and their products, namely, exosomes, are showing promising therapeutic potential due to their low immunogenicity, few ethical concerns, and easy accessibility. Nevertheless, the precise mechanisms underlying the therapeutic effects of MSC-derived exosomes remain unclear. Results Exosomes derived from MSCs reduced hearing and hair cell loss caused by neomycin-induced damage in models in vivo and in vitro. In addition, MSC-derived exosomes modulated autophagy in hair cells to exert a protective effect. Mechanistically, exogenously administered exosomes were internalized by hair cells and subsequently upregulated endocytic gene expression and endosome formation, ultimately leading to autophagy activation. This increased autophagic activity promoted cell survival, decreased the mitochondrial oxidative stress level and the apoptosis rate in hair cells, and ameliorated neomycin-induced ototoxicity. Conclusions In summary, our findings reveal the otoprotective capacity of exogenous exosome-mediated autophagy activation in hair cells in an endocytosis-dependent manner, suggesting possibilities for deafness treatment.

Isolation of bone marrow mesenchymal stem cells in transgenic pigs and co-culture with porcine islets / 器官移植

Objective To investigate the isolation and culture of porcine bone marrow mesenchymal stem cell (BMSC) with α-1, 3-galactosyltransferase (GGTA1) gene knockout (GTKO), GTKO/ human CD46 (hCD46) insertion and cytidine monopho-N-acetylneuraminic acid hydroxylase (CMAH)/GGTA1 gene knockout (Neu5GC/Gal), and the protective effect of co-culture with porcine islets on islet cells. Methods Bone marrow was extracted from different transgenic pigs modified with GTKO, GTKO/hCD46 and Neu5GC/Gal. Porcine BMSC were isolated by the whole bone marrow adherent method and then cultured. The morphology of BMSC was observed and the surface markers of BMSC were identified by flow cytometry. Meantime, the multi-directional differentiation induced by BMSC was observed, and the labeling and tracing of BMSC were realized by green fluorescent protein (GFP) transfection. The porcine BMSC transfected with GFP were co-cultured with porcine islet cells. Morphological changes of porcine islet cells were observed, and compared with those in the porcine islet cell alone culture group. Results BMSC derived from pigs were spindle-shaped in vitro, expressing biomarkers of CD29, CD44, CD73, CD90, CD105 and CD166 rather than CD34 and CD45. These cells were able to differentiate into adipocytes, osteoblasts and chondrocytes. Porcine BMSC with GFP transfection could be labeled and traced, which could be stably expressed in the daughter cells after cell division. Porcine BMSC exerted certain protective effect on islet cells. Conclusions GFP-labeled porcine BMSC modified with GTKO, GTKO/hCD46 and Neu5GC/Gal are successfully established, which exert certain protective effect upon islet cells.

Progress of mesenchymal stem cells in the treatment of bronchopulmonary dysplasia / 国际儿科学杂志

Bronchopulmonary dysplasia(BPD) is a chronic lung disease in the premature infants, which is an important cause of poor prognosis in the premature infants.The pathogenesis of BPD involves a variety of prenatal and postnatal mechanisms affecting the development of immature lungs.The combined effect of BPD alters lung morphogenesis, disrupts capillary gas exchange in the alveoli, and leads to pathological and clinical features of BPD.The current clinical methods used to treat BPD are still difficult to improve its prognosis.Mesenchymal stem/stromal cell(MSC) is a promising and innovative therapy for the treatment of a wide range of diseases due to the ease of extraction, low immunogenicity, anti-inflammatory properties and regenerative ability.In recent years, many experimental and clinical studies have found and proved that mesenchymal stem cell transplantation has a certain effect on BPD, so MSC may become the promising treatment for BPD in the future.However, the possibility that MSC may promote tumor growth, the presence of heterogeneous cell populations resulting in different efficacy, and ethical issues regarding the use of this treatment in humans make it a number of therapeutic challenges.This article reviews the mechanism of action and treatment of MSC in BPD, as well as the research progress in the treatment of BPD with MSC.

A novel mesenchymal stem cell-based regimen for acute myeloid leukemia differentiation therapy

Currently the main treatment of acute myeloid leukemia (AML) is chemotherapy combining hematopoietic stem cell transplantation. However, the unbearable side effect of chemotherapy and the high risk of life-threatening infections and disease relapse following hematopoietic stem cell transplantation restrict its application in clinical practice. Thus, there is an urgent need to develop alternative therapeutic tactics with significant efficacy and attenuated adverse effects. Here, we revealed that umbilical cord-derived mesenchymal stem cells (UC-MSC) efficiently induced AML cell differentiation by shuttling the neutrophil elastase (NE)-packaged extracellular vesicles (EVs) into AML cells. Interestingly, the generation and release of NE-packaged EVs could be dramatically increased by vitamin D receptor (VDR) activation in UC-MSC. Chemical activation of VDR by using its agonist 1α,25-dihydroxyvitamin D3 efficiently enhanced the pro-differentiation capacity of UC-MSC and then alleviated malignant burden in AML mouse model. Based on these discoveries, to evade the risk of hypercalcemia, we synthetized and identified sw-22, a novel non-steroidal VDR agonist, which exerted a synergistic pro-differentiation function with UC-MSC on mitigating the progress of AML. Collectively, our findings provided a non-gene editing MSC-based therapeutic regimen to overcome the differentiation blockade in AML.

Effect of Hypoxia-Supported Umbilical Cord Mesenchymal Stem Cells on the Expansion of Cord Blood Mononuclear Cells in vitro / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of hypoxia-supported umbilical cord mesenchymal stem cell (UC-MSC) on the expansion of cord blood mononuclear cell （MNC） in vitro.@*METHODS@#The isolated cord blood mononuclear cells were inoculated on the preestablished umbilical cord mesenchymal stem cell layer and cultured under hypoxic conditions (3％ O2) and the experimental groups were normoxia (MNCs were cultured under normoxic conditions), hypoxia (MNCs were cultured under hypoxic conditions), UC-MSC (MNCs were cultured with UC-MSC under normoxic conditions), and UC-MSC+hypoxia (MNCs were cultured with UC-MSC under hypoxic conditions). To further investigate the combinational effect of 3 factors of SCF+FL+TPO (SFT) on expansion of cord blood MNCs in vitro in hypoxia-supported UC-MSC culture system, the experiments were further divided into group A (MNCs were cultured with UC-MSC and SFT under normoxic conditions), group B (MNCs were cultured with UC-MSC under hypoxic conditions), group C (MNCs were cultured with UC-MSC and SFT under hypoxic conditions). The number of nucleated cells (TNC), CD34+ cell, CFU and CD34+CXCR4+, CD34+CD49d+, CD34+CD62L+ cells of each groups were detected at 0, 7, 10 and 14 days, respectively.@*RESULTS@#Compared with group hypoxia and UC-MSC, group UC-MSC+hypoxia effectively promoted the expansion of TNC, CD34+ cell and CFU, and upregulated the expression level of adhesion molecule and CxCR4 of the cord blood CD34+ cell（P<0.05）. After culturing for 14 days, compared with group A and group B, group C effectively promoted the expansion of cord blood MNC at different time points（P<0.05）, and the effect of group A was better than that of group B at 7 and 10 days（P<0.05）.@*CONCLUSION@#Hypoxia-supported UC-MSC efficiently promoted the expansion and expression of adhesion molecule and CXCR4 of cord blood CD34+ cell, and the effect of expansion could be enhanced when SFT 3 factors were added.

Effect of PKM2 on Osteogenic and Adipogenic Differentiation of Bone Marrow Mesenchymal Stem Cells in Myeloma Bone Disease / 中国实验血液学杂志

OBJECTIVE@#To investigate the expression of pyruvate kinase M2 (PKM2) in bone marrow mesenchymal stem cells (BMSCs) in myeloma bone disease (MBD) and its effect on osteogenic and adipogenic differentiation of BMSCs.@*METHODS@#BMSCs were isolated from bone marrow of five patients with multiple myeloma (MM) (MM group) and five with iron deficiency anemia (control group) for culture and identification. The expression of PKM2 protein were compared between the two groups. The differences between osteogenic and adipogenic differentiation of BMSCs were assessed by using alkaline phosphatase (ALP) and oil red O staining, and detecting marker genes of osteogenesis and adipogenesis. The effect of MM cell line (RPMI-8226) and BMSCs co-culture on the expression of PKM2 was explored. Functional analysis was performed to investigate the correlations of PKM2 expression of MM-derived BMSCs with osteogenic and adipogenic differentiation by employing PKM2 activator and inhibitor. The role of orlistat was explored in regulating PKM2 expression, osteogenic and adipogenic differentiation of MM-derived BMSCs.@*RESULTS@#Compared with control, MM-originated BMSCs possessed the ability of increased adipogenic and decreased osteogenic differentiation, and higher level of PKM2 protein. Co-culture of MM cells with BMSCs markedly up-regulated the expression of PKM2 of BMSCs. Up-regulation of PKM2 expression could promote adipogenic differentiation and inhibit osteogenic differentiation of MM-derived BMSCs, while down-regulation of PKM2 showed opposite effect. Orlistat significantly promoted osteogenic differentiation in MM-derived BMSCs via inhibiting the expression of PKM2.@*CONCLUSION@#The overexpression of PKM2 can induce the inhibition of osteogenic differentiation of BMSCs in MBD. Orlistat can promote the osteogenic differentiation of BMSCs via inhibiting the expression of PKM2, indicating a potential novel agent of anti-MBD therapy.

MicroRNA-22-3p Regulates the Expression of Kruppel-like Factor 6 to Affect the Cardiomyocyte-like Differentiation of Bone Marrow Mesenchymal Stem Cell / 中国医学科学院学报

Objective To explore the effect of microRNA-22-3p (miR-22-3p) regulating the expression of Kruppel-like factor 6 (KLF6) on the cardiomyocyte-like differentiation of bone marrow mesenchymal stem cell (BMSC). Methods Rat BMSC was isolated and cultured,and the third-generation BMSC was divided into a control group,a 5-azacytidine(5-AZA)group,a mimics-NC group,a miR-22-3p mimics group,a miR-22-3p mimics+pcDNA group,and a miR-22-3p mimics+pcDNA-KLF6 group.Real-time fluorescent quantitative PCR (qRT-PCR) was carried out to determine the expression of miR-22-3p and KLF6 in cells.Immunofluorescence staining was employed to detect the expression of Desmin,cardiac troponin T (cTnT),and connexin 43 (Cx43).Western blotting was employed to determine the protein levels of cTnT,Cx43,Desmin,and KLF6,and flow cytometry to detect the apoptosis of BMSC.The targeting relationship between miR-22-3p and KLF6 was analyzed by dual luciferase reporter gene assay. Results Compared with the control group,5-AZA up-regulated the expression of miR-22-3p (q=7.971,P<0.001),Desmin (q=7.876,P<0.001),cTnT (q=10.272,P<0.001),and Cx43 (q=6.256,P<0.001),increased the apoptosis rate of BMSC (q=12.708,P<0.001),and down-regulated the mRNA (q=20.850,P<0.001) and protein (q=11.080,P<0.001) levels of KLF6.Compared with the 5-AZA group and the mimics-NC group,miR-22-3p mimics up-regulated the expression of miR-22-3p (q=3.591,P<0.001;q=11.650,P<0.001),Desmin (q=5.975,P<0.001;q=13.579,P<0.001),cTnT (q=7.133,P<0.001;q=17.548,P<0.001),and Cx43 (q=4.571,P=0.037;q=11.068,P<0.001),and down-regulated the mRNA (q=7.384,P<0.001;q=28.234,P<0.001) and protein (q=4.594,P=0.036;q=15.945,P<0.001) levels of KLF6.The apoptosis rate of miR-22-3p mimics group was lower than that of 5-AZA group (q=8.216,P<0.001).Compared with the miR-22-3p mimics+pcDNA group,miR-22-3p mimics+pcDNA-KLF6 up-regulated the mRNA(q=23.891,P<0.001) and protein(q=13.378,P<0.001)levels of KLF6,down-regulated the expression of Desmin (q=9.505,P<0.001),cTnT (q=10.985,P<0.001),and Cx43 (q=8.301,P<0.001),and increased the apoptosis rate (q=4.713,P=0.029).The dual luciferase reporter gene experiment demonstrated that KLF6 was a potential target gene of miR-22-3p. Conclusion MiR-22-3p promotes cardiomyocyte-like differentiation of BMSC by inhibiting the expression of KLF6.

Avaliação dos efeitos modulatórios da hematopoese no envelhecimento: Papel das células tronco mesenquimais medulares / Evaluation of the modulatory effects of hematopoiesis during aging: Role of bone marrow mesenchymal stem cells

O envelhecimento é um processo fisiológico que traz consigo uma série de alterações no organismo que se estendem até o nível molecular. Diante disto, este é um processo complexo que afeta diversos tecidos, sendo um deles o hematopoético, local onde, através de interações da Célula Tronco Hematopoética (CTH) com o ambiente ao seu redor, incluindo a Célula Tronco Mesenquimal (CTM), ocorre a hematopoese. Embora já sejam descritas na literatura algumas alterações na medula óssea consequentes do envelhecimento, os mecanismos por trás de tais mudanças permanecem elusivas, principalmente no âmbito das interações celulares ocorrentes na medula óssea. Portanto, este trabalho buscou investigar como o envelhecimento afeta a regulação hematopoética no contexto de sua relação com as CTM medulares. Para esta pesquisa, foram utilizados camundongos machos isogênicos da linhagem C57BL/6, dividindoos em grupos conforme sua idade: jovens (3 ­ 5 meses) e idosos (18 ­ 19 meses). Foi realizada a caracterização do modelo através de aspectos físicos como consumo proteico, variação de peso, entre outros, seguido de avaliação bioquímica e hematológica. Adicionalmente, foram coletadas células medulares e, posteriormente, realizado o isolamento das CTMs. Para estudar a relação destas células com a hematopoese, foram realizados ensaios in vitro utilizando a linhagem celular leucêmica C1498 (TIB-49™, ATCC®) mantidas em contato com o sobrenadante das CTMs isoladas. Quanto aos parâmetros bioquímicos, os animais idosos apresentaram menores níveis de albumina, aspartato alanina transferase (ALT) e de triglicerídeos quando comparados aos animais jovens. Contrariamente, os animais idosos apresentaram um maior nível de colesterol. Na avaliação hematológica, foi constatado pelo hemograma que os animais idosos apresentaram valores comparáveis aos animais jovens, todavia, o mielograma mostrou menor celularidade geral, seguido de menor número de células da linhagem eritroide e maior número de precursores granulocíticos. Através da imunofenotipagem, foi revelado um maior número de CTHs e de precursores grânulosmonocíticos na medula de animais idosos quando comparado aos jovens, e uma menor frequência de progenitores linfoides. Na imunofenotipagem de sangue periférico de animais idosos houve uma redução no número de linfócitos B e de eritrócitos, e aumento na população de células natural killers. Na imunofenotipagem de CTMs, o marcador CD73 apresentou menor expressão nos animais idosos. Avaliando o secretoma destas células estromais, foram encontrados no sobrenadante de CTMs de animais idosos aumentos significativos nas concentrações de CXCL12 e SCF e redução de IL-11. No âmbito molecular, as CTMs de animais idosos apresentaram aumento na expressão de Akt1, Nos e Ppar-γ, e redução na expressão de Csf3 e Cdh2. Adicionalmente, quando comparado a ação das CTMs de animais idosos em relação as CTMs de animais jovens, observou-se que CTMs de animais idosos foram capazes de aumentar a expressão de Sox2, Pou5f1 e Nanog e diminuir a expressão de Cdkn1a de células da linhagem C1498. O sobrenadante de CTMs de animais idosos também resultou na maior proliferação e migração de células da linhagem C1498. Portanto, levando em consideração a importância das CTMs sobre a regulação do sistema hematopoético, pode-se concluir que, no envelhecimento, as CTMs criam um ambiente propício para a proliferação celular no qual a manutenção da pluripotência é estimulada, o que pode acarretar em uma desregulação do sítio hematopoético quando habitado por células malignas

Aging is a physiological process in which occurs a series of alterations in an organism that extend to a molecular level. It is a complex process that affects various tissues, one of them being the bone marrow, wherethrough the interactions of the hematopoietic stem cell (CTH) with its surrounding environment, including with the mesenchymal stem cell (CTM), hematopoiesis takes place. Although some aging-associated alterations in the bone marrow can be found described in the literature, the mechanisms behind said changes remain elusive, especially when regarding the cellular interactions present inside the bone marrow. Therefore, this research aimed to investigate how aging affects the regulation of hematopoiesis in the context of its interactions with bone marrow-derived CTMs. For this investigation, male isogenic C57BL/6 mice were used as animal models. These were separated in two groups according to their age: young (3 ­ 5 months) and aged (18 ­ 19 months). The animal models were characterized by their physical properties such as protein intake and weight variation, followed by biochemical and hematological evaluation. Bone marrow cells were obtained and identified through immunophenotyping, thus isolating different cell populations, including the CTMs. To study the relationship between these cells and hematopoiesis, in vitro assays were conducted utilizing the leukemic cell lineage C1498 (TIB-49™, ATCC®) maintained in contact with the supernatant of isolated CTMs. By their biochemical profile, aged mice showed lower levels of albumin, alanine-aspartate transferase (ALT) and triglycerides compared to the young group. In contrast, aged mice had a higher cholesterol level. Hematological evaluation by total blood count showed similar results between the two groups, however, the myelogram revealed that the aged animals had lower cellularity, with less frequent cells from the erythroid lineage, with an increase in granulocytic precursors. Through immunophenotyping, it was also revealed that aged mice have higher numbers of hematopoietic stem cells, while also being noted a reduced population of lymphoid progenitors. An increase in the granulomonocytic progenitors was also found. Immunophenotyping peripheral blood cells of aged mice revealed reduced numbers of B lymphocytes and erythrocytes, and an increased natural killer cell population. Additionally, the cell surface marker CD73 was found to be less expressed in aged mice CTMs. The secretome of these stromal cells obtained from aged mice showed higher levels of CXCL12 and SCF, and lower levels of IL-11when compared to the young counterparts. At a molecular level, CTMs obtained from aged mice expressed more Akt1, Nos and Ppar-γ, while the expression of Csf3 and Cdh2 was reduced. Additionally, when comparing the effects of aged mice CTMs with young mice CTMs, it was observed that the first expressed were capable of increasing the expression of Sox2, Pou5f1 and Nanog, while decreasing Cdkn1a expression in the C1498 cell lineage. The supernatant obtained from aged mice also favored the proliferation and cell migration of the C1498 cell line. Thus, considering the importance that CTMs have over the hematopoietic system, we can conclude that, in aging, CTMs create a special environment which favors cell proliferation and maintenance of pluripotency, which can result in a dysregulation of the hematopoietic tissue when malignant cells are present

Mesenchymal cells in rotator cuff repair - technique description and case reports / Células mesenquimais no reparo da rotura do manguito rotador - descrição de técnica e relato de casos

ABSTRACT Objective: To describe a protocol of obtention of mesenchymal stem cells and to report their use as a biological adjuvant in three patients undergoing arthroscopic rotator cuff repair. Methods: Case series of patients who underwent arthroscopic repair of isolated full-thickness supraspinatus tear using mesenchymal stem cells obtained from the bone marrow as a biological adjuvant. All patients were operated on at the same institution, by a surgeon with 13 years of experience. The cells were applied at the end of the procedure, at the tendon-bone interface, at an approximate concentration of 2,000,000 mesenchymal cells/mm3 and a total volume of 5 ml. Results: All patients improved with the procedure, with one excellent and two good results. All cases overcame the minimally important clinical difference. All cases reached tendon healing, without partial or complete re-tears. We observed no complications. Conclusion: Arthroscopic rotator cuff repair with added mesenchymal cells obtained from bone marrow and submitted to a cell expansion process led to good functional results and healing in all cases in the sample, with no complications. Level of Evidence IV, Case Series.

RESUMO Objetivo: Descrever o protocolo de obtenção de células mesenquimais e relatar seu uso como adjuvante biológico em três pacientes submetidos ao reparo artroscópico do manguito rotador. Métodos: Série de casos de pacientes submetidos ao reparo artroscópico de rotura transfixante do músculo supraespinal utilizando como adjuvante biológico células mesenquimais obtidas da medula óssea. Todos ospacientes foram operados na mesma instituição por um cirurgião com 13 anos de experiência. As células foram aplicadas ao final do procedimento, na interface do tendão com o osso, na concentração aproximada de 2 milhões de células mesenquimais/mm3 e volume total de 5 ml. Resultados: Todos os pacientes melhoraram após o procedimento, havendo um resultado excelente e dois bons. Todos superaram a diferença clínica minimamente importante. Em todos os casos ocorreu cicatrização tendínea, sem a presença de rerroturas parciais ou completas. Não observamos complicações. Conclusão: O reparo do manguito rotador artroscópico com adição de células mesenquimais obtidas da medula óssea e submetidas a processo de expansão celular levou a bons resultados funcionais e cicatrização, sem complicações, em todos os casos da amostra. Nível de Evidência IV, Série de Casos.

Mesenchymal stem cells modulate IL-17 and IL-9 production induced by Th17-inducing cytokine conditions in autoimmune arthritis: an explorative analysis

Abstract Background The importance of proinflammatory T-cells and their cytokine production in patients with autoimmune arthritis has been widely described. Due to their immunomodulatory properties, mesenchymal stem cells (MSCs) have come into focus as a potential therapeutic concept. The aim of this study was to investigate the influence of MSCs on the phenotype, cytokine profile, and functionality of naive and non-naive CD4+ T-cells from healthy donors (HD) and patients with autoimmune arthritis under Th17-cytokine polarizing conditions in an explorative way using a transwell system prohibiting any cell-cell-contact. Methods Magnetically isolated naive and non-naive CD4+ T-cells were stimulated under Th17-polarizing proinflammatory cytokine conditions in presence and absence of bone marrow derived mesenchymal stromal cells (MSCs). After an incubation period of 6 days, the proportions of the T-cell subpopulations TEMRA (CD45RA+CD27−), memory (CD45RA−CD27+), effector (CD45RA−CD27−) and naive cells (CD45RA+CD27+) were determined. Quantitative immunofluorescence intensity was used as a measure for IL-9, IL-17 and IFN-γ production in each subpopulation. Results In isolated naive CD4+ T-cells from HD and patients, MSCs suppressed the differentiation of naive towards an effector phenotype while memory and naive cells showed higher percentages in culture with MSCs. In patients, MSCs significantly decreased the proportion of IL-9 and IL-17 producing effector T-cells. MSCs also reduced IFN-γ production in the naive and memory phenotype from HD. Conclusions The results of the study indicate significant immunomodulatory properties of MSCs, as under Th17-polarizing conditions MSCs are still able to control T-cell differentiation and proinflammatory cytokine production in both HD and patients with autoimmune arthritis.

Research progress of periodontal tissue regeneration by combined biomaterials of dental derived mesenchymal stem cells / 口腔医学

@#The ultimate treatment goal of periodontitis is the structural and functional regeneration of periodontium. However, existing methods for periodontal regeneration have difficulties in regenerating the hierarchical structure. Therefore, stem cell-based tissue engineering has attracted more and more attention for its advantages of self-renewal and multi-lineage differentiation potential. This review summarized the progress of research on periodontal tissue regeneration by combined biomaterials of dental-derived stem cells. It is pointed out that the application of autologous stem cell transplantation is limited by the donor source, and the subsequent research should focus on the development of multi-phase scaffold materials and the attempt to establish a stem cell bank.

Cross-regulation of Wnt/β-catenin and NF-κB signaling pathway and their involvement in the differentiation of mesenchymal stem cells / 口腔医学

@#Both Wnt/β-catenin signaling pathway and NF-κB signaling pathway are highly conservative pathways that regulate a variety of biological processes, and their cross-regulation have attracted attention in many biological and medical research fields. In this review, we summarize the cross-regulation between Wnt/β-catenin signaling pathway and NF-κB signaling pathway and discuss their involvement in the multi-directional differentiation of mesenchymal stem cells.

Potential value of mesenchymal stem cells and their derivatives in repairing donor liver / 器官移植

In recent years, organ transplantation has developed rapidly in China, whereas the proportion of supply and demand of organs for donation is severely unbalanced. To resolve the shortage of donor livers, repairing extended criteria donor liver and improving the quality of donor liver are critical research directions. Mesenchymal stem cell (MSC) is a category of stem cells with self-renewal and differentiation potential, which possess the functions of immunomodulation and tissue repair. The derivatives of MSC have the advantages of low immunogenicity and high biocompatibility, which have been widely applied in the treatment of multiple diseases. In this article, research progress on the role of MSC, exosomes and extracellular vesicles in alleviating liver steatosis, repairing ischemia-reperfusion injury and promoting the regeneration of small-for-size liver allograft was reviewed, and the feasibility and safety of MSC and the derivatives in repairing donor liver were summarized, aiming provide novel ideas for repairing marginal donor liver and enhancing the quality of liver allograft.

In vitro research of mesenchymal stem cell-coated human islets to alleviate instant blood-mediated inflammatory reaction / 器官移植

Objective To evaluate the effect of mesenchymal stem cell (MSC) coated-islets on instant blood-mediated inflammatory reaction (IBMIR) after islet transplantation. Methods MSC labeled with tracer and human islets were placed into an ultra-low adsorption cell culture dish, shaken and mixed twice at an interval of 0.5 h, and then incubated at 37 ℃ and 5% CO2 for 24 h to obtain MSC-coated islets. The coating effect of MSC and in vitro function of the islets were assessed. A blood circulation tube-shaped model was established in vitro. In the blank control group, 0.2 mL of islet culture solution was added. In the islet group, 800 islet equivalent quantity (IEQ) of uncoated islets were supplemented. In the MSC-coated islets group, 800 IEQ of MSC-coated islets were added, and circulated for 60 min at 37 ℃. A portion of 0.5 mL blood sample was taken for routine blood test at 0, 30 and 60 min, respectively. After 60 min circulation, the blood sample was filtered with a 70 μm filter to collect plasma, blood clots and islets. Blood clots and islets were subject to hematoxylin-eosin (HE) staining and immunohistochemical staining. Morphological changes and the aggregation of CD11b-positive cells surrounding the islets were observed. The contents of plasma thrombin-antithrombin complex (TAT), tissue factor (TF), C3a, C5b-9, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1 and IL-8 were determined by enzyme-linked immune absorbent assay. Results After 24 h co-incubation, the islets were coated by MSC, with a coating degree of approximately 80%. In the islet and MSC-coated islet group, a large quantity of neutrophils and monocytes were observed surrounding the blood clots and islets, and the quantity of CD11b-positive cells in the MSC-coated islet group was less compared with that in the islet group. After co-incubation with the whole blood for 0, 30 and 60 min, the quantity of platelets, neutrophils and monocytes was declined in the MSC-coated and islet groups, and gradually decreased over time. Compared with the blank control group, the quantity of platelets, monocytes and neutrophils was lower, whereas the TF content was higher in the MSC-coated islet group. Compared with the islet group, the quantity of platelets, monocytes and neutrophils was higher, whereas the TAT and TF contents were less in the MSC-coated islet group, the differences were statistically significant (all P < 0.05). Compared with the blank control group, the expression levels of C3a, C5b-9, IL-6, TNF-α and IL-8 were up-regulated in the MSC-coated islet group. Compared with the islet group, the expression levels of C3a, C5b-9, IL-1β, IL-6, TNF-α, IL-8 and MCP-1 were down-regulated in the MSC-coated islet group, and the differences were statistically significant (all P < 0.05). Conclusions MSC-coated islets may reduce the exposure of islet TF in the blood and prevent the incidence of IBMIR during the coagulation response stage, thereby mitigating the injury and loss of islet allograft in the early stage of islet transplantation.

Comparison of Exosomes Derived from Fibroblasts and Mesenchymal Stem Cells for the Treatment of Acute Wound Healing / 中山大学学报(医学科学版)

ObjectiveTo compare the therapeutical effect of exosomes derived from fibroblasts and mesenchymal stem cells on acute wound healing. MethodsPrimary human dermal fibroblasts （hDF） were isolated， cultured and identified. Human bone marrow mesenchymal stem cell exosomes （hMSC-EXO） and hDF exosomes （hDF-EXO） were extracted by ultracentrifuga tion. After 24 h of coincubation with hDF-EXO or hMSC-EXO， hDFs proliferation and migratory capacity were evaluated by cell counting kit-8 （CCK8） assay and scratch test. Full-thickness cutaneous wounds were created on 8-week-old female C57BL/6 mice， and topically applied with PBS （control）， hDF-EXO or hMSC-EXO. Wounds were measured at day 0， 2， 4， 7， and the uptake of exosomes in wound was observed at day 1. Quantitative PCR （qPCR） analysis was performed to detect the mRNA expression levels of TNF-α， IL-6， IL-1β， IL-10 in wound at day 1. HE staining was conducted to analyze the histological structure of wounds at day 7， while immunofluorescence staining was used to examine expression of PDGFR-α、α-SMA、Ki67. ResultshDF exhibited certain fibrolast-like characteristics with respect to expression of cell surface markers and specific proteins. hDF-EXO and hMSC-EXO presented exosomal morphology， size， and markers， and both concentrations were not statistically different （P>0.05）； CCK8 assay showed that both exosomes promoted hDF cell viability， compared with the negative control （P<0.01）， and hDF-EXO group had greater cell viability than hMSC-EXO group （P<0.01）. Scratch test indicated that hDF-EXO induced a significant increase in scratch healing rate versus the negative control （P<0.01）， hMSC-EXO （P<0.05）. In vivo experiments showed wound tissues took up exosomes at day 1. qPCR detected TNF-α， IL-6， IL-1β expression levels in wound at day 1 were lower in exosomes group than in the control group， and were the lowest in hMSC-EXO group （all P<0.01）. Wound areas were measured smaller at day 7 in exosomes group than in the control group （all P<0.01） and hDF-EXO group had better closure than hMSC-EXO group （P<0.05）. HE staining revealed that compared with control group， scar， incomplete epidermis and few collagen deposition remained in the hMSC-EXO group， whereas hDF-EXO group showed re-epithelialization， continuous neo-epidermis and regenerated dermis. Immunofluorescence staining suggested that the number of fibroblasts， myofibroblasts， proliferating cells was higher in both exosomes group than that in the control group， especially the highest in hDF-EXO group. ConclusionOur study shows both exosomes accelerate wound healing， whereas hDF-EXO is more effective in promoting fibroblasts proliferation， migration， transition to myofibroblasts， and hMSC-EXO may play a role in inhibiting inflammatory reaction during early stage of wound healing.

Mechanism of regulatory effect of recombinant human HMGB1 on endothelial cell angiogenesis / 器官移植

Objective To unravel the possible mechanism of the role of recombinant human high mobility group box 1 (rhHMGB1) protein in regulating the angiogenesis of endothelial cells. Methods Endothelial cells were divided into the control group, bone marrow mesenchymal stem cells (MSC) supernatant group and rhHMGB1 group. The proliferation and survival of endothelial cells were detected by cell counting kit(CCK)-8 assay. The relative expression levels of vascular endothelial growth factor (VEGF), Yes-associated protein (YAP), CD31 and hypoxia inducible factor (HIF)-1α proteins were determined by Western blot. The relative expression levels of VEGF, YAP, CD31 and HIF-1α messenger RNA (mRNA) were detected by real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). The migration ability of endothelial cells was assessed by Transwell chamber test. The localization of YAP was detected by immunofluorescence staining. Results Compared with the control group, the migration rate of endothelial cells was increased in the rhHMGB1 group (P < 0.05), and the cell migration rate was enhanced over time. Compared with the control group, the relative expression levels of VEGF and p-YAP proteins were up-regulated in the MSC supernatant group, and the differences were statistically significant (both P < 0.05). Compared with the control group, the relative expression levels of VEGF and HIF-1α proteins, VEGF and CD31 mRNA and YAP and p-YAP proteins were up-regulated, and YAP/p-YAP ratio was increased in the rhHMGB1 group, and the differences were statistically significant (all P < 0.05). Compared with the MSC supernatant group, the relative expression levels of CD31 mRNA and YAP protein were up-regulated, and the YAP/p-YAP ratio was increased in the rhHMGB1 group, and the differences were statistically significant (all P < 0.05). Conclusions Exogenous high-concentration rhHMGB1 may promote the migration ability of endothelial cells and up-regulate the expression levels of angiogenesis-related proteins by regulating the recruitment of YAP to the nucleus.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles enhance the regenerative capability of fibrotic liver / 器官移植

Objective To investigate the role of human umbilical cord mesenchymal stem cell-derived extracellular vesicle (hUC-MSC-EV) in the regeneration of fibrotic liver. Methods C57BL/6 mice were randomly divided into the 70% normal liver resection group (Oil+PHx group), 70% liver fibrosis resection group (CCl4+PHx group) and 70% liver fibrosis resection+mesenchymal stem cell-derived extracellular vesicle (MSC-EV) treatment group (CCl4+PHx+MSC-EV group), with 8 mice in each group. LX-2 cell lines were assigned into the phosphate buffer solution (PBS) group, transforming growth factor (TGF)-β group and TGF-β+MSC-EV group. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in mice after partial liver resection were detected in each group. The expression levels of liver fibrosis and proliferation-related parameters were analyzed in each group. The messenger RNA (mRNA) expression levels of epidermal growth factor (EGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) in LX-2 cells were detected in each group, and their effects on HGF expression in mouse liver were observed. Results Compared with the Oil+PHx group, the serum levels of AST, ALT and LDH were up-regulated, and the degree of fibrosis was more severe, the positive area of Sirius red and α-smooth muscle actin (α-SMA) staining was larger, and the expression level of α-SMA protein was up-regulated in the CCl4+PHx group. Compared with the CCl4+PHx group, the serum levels of AST, ALT and LDH were decreased, the degree of fibrosis was slighter, the positive area of Sirius red and α-SMA staining was decreased, and the expression level of α-SMA protein was down-regulated in the CCl4+PHx+MSC-EV group, and the differences were statistically significant (all P < 0.05). Compared with the Oil+PHx group, the protein expression levels of Ki67 and proliferating cell nuclear antigen (PCNA) were lower in the CCl4+PHx group. Compared with the CCl4+PHx group, the protein expression levels of Ki67 and PCNA were increased in the CCl4+PHx+MSC-EV group, and the differences were statistically significant (all P < 0.05). Compared with the PBS group, the expression level of CollagenⅠ mRNA in LX-2 cells was increased, the expression level of α-SMA protein was up-regulated and the expression level of HGF protein was decreased in the TGF-β group. Compared with the TGF-β group, the expression level of CollagenⅠ mRNA in LX-2 cells was decreased, the expression levels of HGF mRNA and protein were increased, and the expression level of α-SMA protein was decreased in the TGF-β+MSC-EV group, the differences were statistically significant (all P < 0.05). The expression level of HGF protein in the CCl4+PHx group was lower than that in the Oil+PHx group, whereas the difference was not statistically significant (P > 0.05). The expression level of HGF protein in the CCl4+PHx+MSC-EV group was higher than that in the CCl4+PHx group, and the difference was statistically significant (P < 0.05). Conclusions The regenerative capacity of fibrotic liver is weaker than that of normal liver. hUC-MSC-EV may alleviate liver fibrosis and improve liver regeneration by promoting HGF secretion from actived hepatic stellate cells and effectively enhancing the regenerative capacity of fibrotic liver.

Protective role and mechanism of human umbilical cord mesenchymal stem cell-derived exosome in renal ischemia-reperfusion injury / 器官移植

Objective To investigate the protective effect of human umbilical cord mesenchymal stem cell-derived exosome (hucMSC-Exo) on renal ischemia-reperfusion injury (IRI), and to clarify the critical role and regulating mechanism of transient receptor potential canonical (TRPC) 6/poly adenosine-diphosphate-ribose polymerase (PARP) 1 signaling pathway during this process. Methods The hucMSC-Exo was extracted by ultracentrifugation, and identified by transmission electron microscope (TEM), nanoparticle tracing analysis and Western blot. SD rats were randomly divided into the sham operation group (group S), sham operation+TRPC6 inhibitor SKF96365 group (group SS), renal IRI group (group IRI), exosome treatment group (group EXO) and exosome +TRPC6 inhibitor SKF96365 group (group ES), with 6 rats in each group. Serum creatinine and blood urea nitrogen levels were detected. Pathological changes of renal tissues were observed by hematoxylin-eosin (HE) staining and Paller score was calculated. The expression levels of key molecules of necroptosis in rat renal tissues, including receptor-interacting protein kinase (RIPK)1, RIPK3 and mixed-lineage kinase domain-like protein (MLKL), TRPC6 and PARP1, were detected by Western blot. Results Typical saucer-like structure was observed under TEM. Nanoparticle tracing analysis showed that the average diameter of the extracted substance was 125.9 nm. Western blot revealed that the surface markers of CD9, CD63 and CD81 were positively expressed, confirmed that the extracted substance was exosome. Compared with group S, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was worsened, Paller score was elevated, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group IRI (all P < 0.05). Compared with group IRI, the serum creatinine and blood urea nitrogen levels were down-regulated, the pathological damage of renal tissues was mitigated, Paller score was decreased, the relative expression levels of TRPC6 and PARP1 proteins were up-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were down-regulated in group EXO (all P < 0.05). Compared with group EXO, the serum creatinine and blood urea nitrogen levels were up-regulated, the pathological damage of renal tissues was aggravated, Paller score was increased, the relative expression levels of TRPC6 and PARP1 proteins were down-regulated, and the relative expression levels of RIPK1, RIPK3 and MLKL proteins were up-regulated in group ES (all P < 0.05). Conclusions hucMSC-Exo may alleviate the necroptosis induced by renal IRI in rat models, which is related to the activation of TRPC6/PARP1 signaling pathway.

Prevention and treatment of chronic graft-versus-host disease by mesenchymal stem cells: advances and challenges / 器官移植

Chronic graft-versus-host disease (cGVHD) is the main complication after allogeneic hematopoietic stem cell transplantation, which is also the major cause of non-relapse -related death. Due to its complex pathophysiological process, the response rate of conventional glucocorticoids combined with immunosuppressants is less than 50%. Second-line therapy should be given for patients with glucocorticoid-resistant cGVHD. Nevertheless, no consensus has been reached on current second-line therapy and the therapeutic effect is relatively poor. Mesenchymal stem cell (MSC) is one of the most common adult stem cells. Due to multi-dimensional and multi-target immune regulating function, MSC has been widely applied in the prevention and treatment of cGVHD. In addition, accumulated studies have confirmed the safety and efficacy of MSC in the treatment of cGVHD, which is expected to become a novel strategy for the prevention and management of cGVHD. In this article, research progress, mechanism and existing problems of prevention and treatment of cGVHD by MSC were reviewed, aiming to provide novel ideas for optimizing therapeutic regimens of MSC and enhancing the prevention and treatment effect of cGVHD in subsequent research.

Current status and reflections on stem cell transplantation in the treatment of testicular aging / 器官移植

Testicular aging is mainly characterized by a gradual decline in the capability of testosterone synthesis and spermatogenesis, which not only affects male fertility, but also correlates with aging-related chronic diseases intimately. Therefore, delaying testicular aging plays a significant role in improving the health and quality of life of middle-aged and elderly men. Stem cells are a cell group with potent self-renewal capability and multi-directional differentiation potential. In recent years, the research of stem cells in basic and clinical application has been carried out in-depth, which has accelerated the development of cell therapy. Currently, stem cell transplantation has been employed to treat multiple diseases, which has captivated widespread attention in the field of aging and regenerative medicine. Stem cell transplantation has demonstrated promising prospects in the treatment of testicular aging. In this article, research profile and progress of stem cell transplantation in the treatment of testicular aging were reviewed, and bottleneck issues encountered in clinical translation and strategies for optimizing clinical efficacy were discussed, aiming to provide novel ideas for the research and development and clinical translation of stem cell therapy for testicular aging.