The sustained PGE2 release matrix improves neovascularization and skeletal muscle regeneration in a hindlimb ischemia model.

BACKGROUND: The promising therapeutic strategy for the treatment of peripheral artery disease (PAD) is to restore blood supply and promote regeneration of skeletal muscle regeneration. Increasing evidence revealed that prostaglandin E2 (PGE2), a lipid signaling molecule, has significant therapeutic potential for tissue repair and regeneration. Though PGE2 has been well reported in tissue regeneration, the application of PGE2 is hampered by its short half-life in vivo and the lack of a viable system for sustained release of PGE2. RESULTS: In this study, we designed and synthesized a new PGE2 release matrix by chemically bonding PGE2 to collagen. Our results revealed that the PGE2 matrix effectively extends the half-life of PGE2 in vitro and in vivo. Moreover, the PGE2 matrix markedly improved neovascularization by increasing angiogenesis, as confirmed by bioluminescence imaging (BLI). Furthermore, the PGE2 matrix exhibits superior therapeutic efficacy in the hindlimb ischemia model through the activation of MyoD1-mediated muscle stem cells, which is consistent with accelerated structural recovery of skeletal muscle, as evidenced by histological analysis. CONCLUSIONS: Our findings highlight the chemical bonding strategy of chemical bonding PGE2 to collagen for sustained release and may facilitate the development of PGE2-based therapies to significantly improve tissue regeneration.

In vivo two-photon microscopy reveals the contribution of Sox9+ cell to kidney regeneration in a mouse model with extracellular vesicle treatment.

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) have been shown to stimulate regeneration in the treatment of kidney injury. Renal regeneration is also thought to be stimulated by the activation of Sox9+ cells. However, whether and how the activation mechanisms underlying EV treatment and Sox9+ cell-dependent regeneration intersect is unclear. We reasoned that a high-resolution imaging platform in living animals could help to untangle this system. To test this idea, we first applied EVs derived from human placenta-derived MSCs (hP-MSCs) to a Sox9-CreERT2; R26mTmG transgenic mouse model of acute kidney injury (AKI). Then, we developed an abdominal imaging window in the mouse and tracked the Sox9+ cells in the inducible Sox9-Cre transgenic mice via in vivo lineage tracing with two-photon intravital microscopy. Our results demonstrated that EVs can travel to the injured kidneys post intravenous injection as visualized by Gaussia luciferase imaging and markedly increase the activation of Sox9+ cells. Moreover, the two-photon living imaging of lineage-labeled Sox9+ cells showed that the EVs promoted the expansion of Sox9+ cells in kidneys post AKI. Histological staining results confirmed that the descendants of Sox9+ cells contributed to nephric tubule regeneration which significantly ameliorated the renal function after AKI. In summary, intravital lineage tracing with two-photon microscopy through an embedded abdominal imaging window provides a practical strategy to investigate the beneficial functions and to clarify the mechanisms of regenerative therapies in AKI.

Heterogeneity of Human Mesenchymal Stromal/Stem Cells.

Increasing evidence has shown that mesenchymal stem cells (MSCs) isolated from body tissues are heterogeneous while being examined in vitro and in vivo. Besides some common characteristics, MSCs derived from different tissues exhibit unique biological properties. In addition, the therapeutic effects of MSCs may vary widely due to their heterogeneity and the technical differences in large-scale ex vivo expansion. In this chapter, the heterogeneity of MSCs will be discussed in three levels: the individual donors, the tissue sources, and the cell surface markers.

[Comparison of the Biological Functions between Human Bone Marrow Derived CD106 +Mesenchymal Stem Cells and CD106 - Subgroup].

Objective To analyze the differences in biological functions between bone marrow(BM)-derived CD106 +mesenchymal stem cells(MSCs)and the CD106 - subgroup. Methods The MSCs from normal BM were isolated and expanded.The subgroups of CD106 + and CD106 -MSCs were sorted.The cell proliferation and adhesion functions,chemotactic activities,adipogenic and osteogenic potentials,senescence,and senescence protein 21(p21)were detected.The capacity of translocation into nucleus of nuclear factor-kappa B(NF-κB)when stimulated by tumor necrosis factor(TNF-α)was measured. Results The proliferative ability was higher in CD106 +MSCs than that in CD106 -MSCs.In 48 hours,the value of optical density(OD)was significantly higher in CD106 +MSCs than that in CD106 - subgroup(1.004±0.028 vs. 0.659±0.023,t=3.946,P=0.0225).In 72 hours,this phenomenon was even more pronounced(2.574±0.089 vs. 1.590±0.074,t=11.240,P=0.0000).The adhesive capacity of CD106 +MSCs was significantly stronger than that of CD106 - subgroup(0.648±0.018 vs. 0.418±0.023,t=7.869,P=0.0002).Besides,the metastasis ability of CD106 +MSCs were significantly stronger than that of CD106 - subgroup(114.500±4.481 vs.71.000±4.435,t=6.900,P=0.0005).The CD106 +MSCs had signifcnatly lower proportions of senescent cells.The expression of aging protein p21 in CD106 +MSCs was significantly lower than that in CD106 -MSCs [(17.560±1.421)% vs.(45.800±2.569)%,t=9.618,P=0.0000].Furthermore,there were no visible pigmenting cells after ß-galactosidase staining in CD106 +MSCs subgroup.However,in CD106 -MSCs,some colored green cells were detected.The rate of NF-κB translocation into nucleus after stimulated by TNF-α was significantly higher in CD106 +MSCs than CD106 - MSCs [(37.780±3.268)% vs.(7.30±1.25)%,t=8.713,P=0.0001]. Conclusion Bone marrow-derived CD106 +MSCs possess more powerful biological functions than CD106 -MSCs.

[Effect of CD106+ Mesenchymal Stem Cell on Bone Marrow Vascular Failure in Patients with Aplastic Anemia].

Objective To investigate the vascularization ability of mesenchymal stem cells(MSCs)and explore its influencing factors in aplastic anemia(AA) patients. Methods MSCs were isolated from the bone marrow of AA patients(AA MSCs) and normal controls(N MSCs) were cultured and then evaluated by flow cytometry and immunofluorescene staining technique.The expression level of vascular cell adhesion molecule-1(CD106) was detected by gene sequencing,and the content and fluorescene intensity of CD106+MSCs was determined by fluorescence-activated cell sorting.The content of CD105+CD106+MSCs in fresh AA bone marrow was measured,followed by the determination of the capability of endothelial differentiation from AA MSCs and N MSCs with immunofluorescene analysis;finally,the capability of CD31+cell differentiation from CD106-blocking N MSCs and its tubular structures formation in matrigel were tested.Results The expression of CD106 in AA patients was defective(decreased by 12.13 times when compared with N MSCs) and the concentration and fluorescene degree of CD106+MSCs was also decreased in AA patients [(28.03±17.71)% vs.(59.61±12.26)%,P=0.000].The content of CD105+CD106+MSCs decreased significantly in the fresh bone marrow [(0.33±0.10)% vs.(2.98±0.46)%,P=0.0005].Besides, the capability of CD31+cell differentiation from AA MSCs was significantly delayed [(13.67±1.50)% vs.(43.24±0.96)%,P=0.0004].Also,the capability of CD31+cell differentiation and tubular structures formation of CD106-blocking N MSCs was also obviously decreased [(26.00±2.65)% vs.(91.78±2.44)%,P=0.000;(13.81±1.98)mm vs.(68.12±6.78)mm,P=0.0015].Conclusion The deficient or decreased expression of CD106+MSCs accelerate the bone marrow vascularization failure in AA patients.

[Human Umbilical Cord-derived Mesenchymal Stem Cells Secrete Interleukin-6 to Influence Differentiation of Leukemic Cells].

OBJECTIVE: To investigate the effect of human umbilical cord-derived mesenchymal stem cells (UC-MSC) on the differentiation of leukemic cells. METHODS: The co-culture system of UC-MSC with acute promyelocytic leukemic cell line NB4 cells was constructed in vitro,and the differentiation status of the leukemic cells was assessed by cell morphology,nitroblue tetrazolium reduction test,and cell surface differentiation marker CD11b. RESULTS: UC-MSC induced the granulocytic differentiation of NB4 cells. When UC-MSC and a small dose of all-trans retinoic acid were applied together,the differentiation-inducing effect was enhanced in an additive manner. Interleukin (IL)-6Ra neutralization attenuated differentiation and exogenous IL-6-induced differentiation of leukemic cells. CONCLUSION: UC-MSC can promotd granulocytic differentiation of acute promyelocytic leukemia cells by way of IL-6 and presented additive effect when combined with a small dose of all-trans retinoic acid.

Inhibition of Notch Signaling Promotes the Adipogenic Differentiation of Mesenchymal Stem Cells Through Autophagy Activation and PTEN-PI3K/AKT/mTOR Pathway.

BACKGROUND: The Notch signaling pathway is implicated in a broad range of developmental processes, including cell fate decisions. This study was designed to determine the role of Notch signaling in adipogenic differentiation of human bone marrow derived MSCs (BM-MSCs). METHODS: The Notch signaling was inhibited by the γ-secretase inhibitor N-[N-(3,5-difluor- ophenacetyl-L-alanyl)]-S-phenylglycine t-butylester (DAPT). The markers involving adipogenic differentiation of MSCs, the relative pathway PTEN-PI3K/Akt/mTOR and autophagy activation were then analyzed. Furthermore, the autophagy inhibitor chloroquine (CQ) and 3-methyladenine (3-MA) were used to study the role of autophagy in the DAPT-induced the adipogenic differentiation of MSCs. RESULTS: We first confirmed the down -regulation of Notch gene expression during MSCs adipocyte differentiation, and showed that the inhibition of Notch signaling significantly enhanced adipogenic differentiation of MSCs. Furthermore, Notch inhibitor DAPT induced early autophagy by acting on PTEN-PI3K/Akt/mTOR pathway. The autophagy inhibitor CQ and 3-MA dramatically abolished the effects of DAPT-induced autophagy and adipogenic differentiation of MSCs. CONCLUSION: Our results indicate that inhibition of Notch signaling could promote MSCs adipogenesis mediated by autophagy involving PTEN-PI3K/Akt/mTOR pathway. Notch signaling could be a novel target for regulating the adipogenic differentiation of MSCs.

Transfer of the IL-37b gene elicits anti-tumor responses in mice bearing 4T1 breast cancer.

AIM: IL-37b has shown anti-cancer activities in addition to its anti-inflammatory properties. In this study, we investigated the effects of IL-37b on breast carcinoma growth in mice and to determine the involvement of T cell activation in the effects. METHODS: IL-37b gene was transferred into mouse breast carcinoma cell line 4T1 (4T1-IL37b cells), the expression of secretory IL-37b by the cells was detected, and the effects of IL-37b expression on the cell proliferation in vitro was evaluated. After injection of 4T1 cells or 4T1-IL37b cells into immunocompetent BALB/c mice, immunodeficient BALB/c nude mice and NOD-SCID mice, the tumor growth and survival rate were measured. The proliferation of T cells in vitro was also detected. RESULTS: IL-37b was detected in the supernatants of 4T1-IL37b cells with a concentration of 12.02 ± 0.875 ng/mL. IL-37b expression did not affect 4T1 cell proliferation in vitro. BALB/c mice inoculated with 4T1-IL37b cells showed significant retardation of tumor growth. BALB/c mice inoculated with both 4T1 cells and mitomycin C-treated 4T1-IL37b cells also showed significant retardation of tumor growth. But the anti-cancer activity of IL-37b was abrogated in BALB/c nude mice and NOD-SCID mice inoculated with 4T1-IL37b cells. Recombinant IL-37b slightly promoted CD4(+) T cell proliferation without affecting CD8(+) T cell proliferation. CONCLUSION: IL-37b exerts anti-4T1 breast carcinoma effects in vivo by modulating the tumor microenvironment and influencing T cell activation.

Serum-free media and the immunoregulatory properties of mesenchymal stem cells in vivo and in vitro.

BACKGROUND: Mesenchymal stem cells are capable of self-renewal and multi-lineage differentiation. They are used extensively to treat several diseases. Traditionally, mesenchymal stem cells are cultured in serum-containing media, typically supplemented with fetal bovine serum (FBS). However, the variability of FBS is likely to skew experimental results. Although serum-free media used to expand mesenchymal stem cells has facilitated remarkable achievements, immunomodulation of these cells in under serum-free conditions is poorly understood. We hypothesized that mesenchymal stem cells expanded in serum-free media will retain powerful immunoregulatory functions in vitro and in vivo. DESIGN AND METHODS: Immunosuppressive activity and the immunomodulatory cytokines produced by mesenchymal stem cells in serum-free media were characterized in vitro. Immunomodulation by serum-free mesenchymal stem cell expansion in monocrotaline-induced pulmonary hypertension was explored in vivo. RESULTS: Similar to cells in serum-containing media, mesenchymal stem cells expanded in serum-free media inhibited proliferation and apoptosis of CD4(+)T cells. They also exhibited strong immunosuppressive activities and secreted high levels of immunomodulatory cytokines such as PGE2, IDO1, COX2, IL-6, and IL-1ß, but not HGF. On the other hand, growth of mesenchymal stem cells in serum-free media attenuated pulmonary vascular remodeling and inhibited mRNA expression of proinflammatory cytokines TNF-α, IFN-γ, IL-6, IL-1ß, and IL-18. CONCLUSIONS: Mesenchymal stem cells in serum-free media maintained powerful immunomodulatory function in vitro and in vivo; serum-free media may replace serum-containing media for basic research and clinical applications.

Combined lineage tracing and scRNA-seq reveal the activation of Sox9+ cells in renal regeneration with PGE2 treatment.

Uncovering mechanisms of endogenous regeneration and repair through resident stem cell activation will allow us to develop specific therapies for injuries and diseases by targeting resident stem cell lineages. Sox9+ stem cells have been reported to play an essential role in acute kidney injury (AKI). However, a complete view of the Sox9+ lineage was not well investigated to accurately elucidate the functional end state and the choice of cell fate during tissue repair after AKI. To identify the mechanisms of fate determination of Sox9+ stem cells, we set up an AKI model with prostaglandin E2 (PGE2) treatment in a Sox9 lineage tracing mouse model. Single-cell RNA sequencing (scRNA-seq) was performed to analyse the transcriptomic profile of the Sox9+ lineage. Our results revealed that PGE2 could activate renal Sox9+ cells and promote the differentiation of Sox9+ cells into renal proximal tubular epithelial cells and inhibit the development of fibrosis. Furthermore, single-cell transcriptome analysis demonstrated that PGE2 could regulate the restoration of lipid metabolism homeostasis in proximal tubular epithelial cells by participating in communication with different cell types. Our results highlight the prospects for the activation of endogenous renal Sox9+ stem cells with PGE2 for the regenerative therapy of AKI.

MicroRNA-124 suppresses breast cancer cell growth and motility by targeting CD151.

BACKGROUND: CD151 is highly expressed in breast cancer cells and has been shown to accelerate breast cancer by enhancing cell growth and motility, but its regulation is poorly understood. To explore post-translation regulation of CD151, for example microRNAs, will be of great importance to claim the mechanism. METHODS: A luciferase reporter assay was used to determine whether CD151 was a target of miR-124. The levels of CD151 mRNA were detected by real-time PCR and CD151 protein expression was measured by western blot and flow cytometry. The effects of miR-124 expression on growth, apoptosis, cell cycle and motility of breast cancer cells were determined. RESULTS: We discovered that miR-124 directly targets the 3' untranslated region (3'-UTR) of CD151 mRNAs and suppresses its mRNA expression and protein translation. Both siRNA of CD151 and miR-124 mimics could significantly inhibit proliferation of breast cancer cell lines via cell cycle arrest but does not induce apoptosis. Meanwhile, miR-124 mimics significantly inhibited the motility of breast cancer cells. CONCLUSION: miR-124 plays a critical role in inhibiting the invasive and metastatic potential of breast cancer cells, probably by directly targeting the CD151 genes. Our findings highlight an important role of miR-124 in the regulation of invasion and metastasis by breast cancer cells and suggest a potential application for miR-124 in breast cancer treatment.

[Culture of pancreatic progenitor cells in hanging drop and on floating filter].

OBJECTIVE: To construct a method to culture pancreatic progenitor cells in hanging drop and on floating filter,and to examine if pancreatic progenitor cells can differentiate into mature endocrine cells with this method. METHODS: Murine embryos at day 12.5 were isolated and digested into single cells,which were then cultured in hanging drop for 24h and formed spheres.Spheres were cultured on the filter for 6 days,which floated in the dish containing medium.During culture,the expressions of pancreas duodenum homeobox-1(PDX-1)and neurogenin3(Ngn3)were determined.The expressions of endocrine and exocrine markers,insulin,glucagon,and carboxypeptidase(CPA)were determined on day 7 by immunohistochemistry.Insulin secretion of spheres stimulated by glucose was detected by ELISA.The changes of pancreatic marker expressions during culture were monitored by real-time polymerase chain reaction(PCR). RESULTS: One day after the culture,there were still a large amount of PDX-1 positive cells in pancreatic spheres,and these cells proliferated.On day 3,high expression of Ngn3 was detected,and the Ngn3-positive cells did not proliferate.On day 7,The expressions of endocrine and exocrine markers in the differentiated pancreatic progenitor cells were detected,which were consistent with that in vivo.Insulin was secreted by spheres upon the stimulation of glucose. CONCLUSION: In hanging drop and on floating filter,pancreatic progenitor cells can differentiate into mature endocrine cells.

[Comparative Study of the Two High-Efficient Strategies for in vitro Generation of Human Umbilical Cord Blood-derived Natural Killer Cells].

OBJECTIVE: To explore the similarities and variations of biological phenotype and cytotoxicity of human umbilical cord blood natural killer cells (hUC- NK) after human umbilical cord blood-derived mononuclear cells (hUC-MNC) activated and expanded by two in vitro high-efficient strategies. METHODS: Umbilical cord blood mononuclear cells (MNC) from healthy donor were enriched by Ficoll-based density gradient centrifugation. Then, the phenotype, subpopulations, cell viability and cytotoxicity of NK cells derived from Miltenyi medium (denoted as M-NK) and X-VIVO 15 (denoted as X-NK) were compared using a "3IL" strategy. RESULTS: After a 14-day's culture, the contents of CD3-CD56+ NK cells were elevated from 4.25%±0.04% (d 0) to 71%±0.18% (M-NK) and 75.2%±1.1% (X-NK) respectively. Compared with X-NK group, the proportion of CD3+CD4+ T cells and CD3+CD56+ NKT cells in M-NK group decreased significantly. The percentages of CD16+, NKG2D+, NKp44+, CD25+ NK cells in X-NK group was higher than those in the M-NK group, while the total number of expanded NK cells in X-NK group was half of that in M-NK group. There were no significant differences between X-NK and M-NK groups in cell proliferation and cell cycle, except for the lower percentage of Annexin V+ apoptotic cells in M-NK group. Compared with X-NK group, the proportion of CD107a+ NK cells in M-NK group were higher under the same effector-target ratio (E∶T) (P<0.05). CONCLUSION: The two strategies were adequate for high-efficient generation of NK cells with high level of activation in vitro, however, there are differences in biological phenotypes and tumor cytotoxicity.

Superior protective effects of PGE2 priming mesenchymal stem cells against LPS-induced acute lung injury (ALI) through macrophage immunomodulation.

BACKGROUND: Mesenchymal stem cells (MSCs) have demonstrated remarkable therapeutic promise for acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS). MSC secretomes contain various immunoregulatory mediators that modulate both innate and adaptive immune responses. Priming MSCs has been widely considered to boost their therapeutic efficacy for a variety of diseases. Prostaglandin E2 (PGE2) plays a vital role in physiological processes that mediate the regeneration of injured organs. METHODS: This work utilized PGE2 to prime MSCs and investigated their therapeutic potential in ALI models. MSCs were obtained from human placental tissue. MSCs were transduced with firefly luciferase (Fluc)/eGFP fusion protein for real-time monitoring of MSC migration. Comprehensive genomic analyses explored the therapeutic effects and molecular mechanisms of PGE2-primed MSCs in LPS-induced ALI models. RESULTS: Our results demonstrated that PGE2-MSCs effectively ameliorated lung injury and decreased total cell numbers, neutrophils, macrophages, and protein levels in bronchoalveolar lavage fluid (BALF). Meanwhile, treating ALI mice with PGE2-MSCs dramatically reduced histopathological changes and proinflammatory cytokines while increasing anti-inflammatory cytokines. Furthermore, our findings supported that PGE2 priming improved the therapeutic efficacy of MSCs through M2 macrophage polarization. CONCLUSION: PGE2-MSC therapy significantly reduced the severity of LPS-induced ALI in mice by modulating macrophage polarization and cytokine production. This strategy boosts the therapeutic efficacy of MSCs in cell-based ALI therapy.

Genetically engineered mesenchymal stem cells as a nitric oxide reservoir for acute kidney injury therapy.

Nitric oxide (NO), as a gaseous therapeutic agent, shows great potential for the treatment of many kinds of diseases. Although various NO delivery systems have emerged, the immunogenicity and long-term toxicity of artificial carriers hinder the potential clinical translation of these gas therapeutics. Mesenchymal stem cells (MSCs), with the capacities of self-renewal, differentiation, and low immunogenicity, have been used as living carriers. However, MSCs as gaseous signaling molecule (GSM) carriers have not been reported. In this study, human MSCs were genetically modified to produce mutant ß-galactosidase (ß-GALH363A). Furthermore, a new NO prodrug, 6-methyl-galactose-benzyl-oxy NONOate (MGP), was designed. MGP can enter cells and selectively trigger NO release from genetically engineered MSCs (eMSCs) in the presence of ß-GALH363A. Moreover, our results revealed that eMSCs can release NO when MGP is systemically administered in a mouse model of acute kidney injury (AKI), which can achieve NO release in a precise spatiotemporal manner and augment the therapeutic efficiency of MSCs. This eMSC and NO prodrug system provides a unique and tunable platform for GSM delivery and holds promise for regenerative therapy by enhancing the therapeutic efficiency of stem cells.

Animals are made up of cells of different types, with each type of cell specializing on a specific role. But for the body to work properly, the different types of cells must be able to coordinate with each other to respond to internal and external stimuli. This can be achieved through signaling molecules, that is, molecules released by a cell that can elicit a specific response in other cells. There are many types of different molecules, including hormones and signaling proteins. Gases can also be potent signaling molecules, participating in various biological processes. Nitric oxide (NO) is a gas signaling molecule that can freely diffuse through the membranes of cells and has roles in blood vessel constriction and other disease processes, making it a promising therapeutic agent. Unfortunately, using artificial carriers to deliver nitric oxide to the organs and tissues where it is needed can lead to issues, including immune reactions to the carrier and long-term toxicity. One way to avoid these effects is by using cells to deliver nitric oxide to the right place. Huang, Qian, Liu et al. have used mesenchymal stem cells ­ which usually develop to form connective tissues such as bone and muscle ­ to develop a cell-based NO-delivery system. The researchers genetically modified the mesenchymal stem cells to produce a compound called ß-GAL^H363A. On its own ß-GAL^H363A does not do much, but in its presence, a non-toxic, non-reactive compound developed by Huang, Qian, Liu et al., called MGP, can drive the release of NO from cells. To confirm the usefulness of their cells as a delivery system, Huang, Qian, Liu et al. transplanted some of the genetically modified mesenchymal stem cells into the kidneys of mice, and then showed that when these mice were given MGP, the levels of NO increased in the kidneys but not in other organs. This result confirms that the cell-based delivery system provides spatial and temporal control of the production of NO. These findings demonstrate a new delivery system for therapies using gas molecules, which can be controlled spatiotemporally in mice. In the future, these types of systems could be used in the clinic for long-term treatment of conditions where artificial carriers could lead to complications.

Renal Endothelial Cell-Targeted Extracellular Vesicles Protect the Kidney from Ischemic Injury.

Endothelial cell injury plays a critical part in ischemic acute kidney injury (AKI) and participates in the progression of AKI. Targeting renal endothelial cell therapy may ameliorate vascular injury and further improve the prognosis of ischemic AKI. Here, P-selectin as a biomarker of ischemic AKI in endothelial cells is identified and P-selectin binding peptide (PBP)-engineered extracellular vesicles (PBP-EVs) with imaging and therapeutic functions are developed. The results show that PBP-EVs exhibit a selective targeting tendency to injured kidneys, while providing spatiotemporal information for the early diagnosis of AKI by quantifying the expression of P-selectin in the kidneys by molecular imaging. Meanwhile, PBP-EVs reveal superior nephroprotective functions in the promotion of renal repair and inhibition of fibrosis by alleviating inflammatory infiltration, improving reparative angiogenesis, and ameliorating maladaptive repair of the renal parenchyma. In conclusion, PBP-EVs, as an ischemic AKI theranostic system that is designed in this study, provide a spatiotemporal diagnosis in the early stages of AKI to help guide personalized therapy and exhibit superior nephroprotective effects, offering proof-of-concept data to design EV-based theranostic strategies to promote renal recovery and further improve long-term outcomes following AKI.

Mesenchymal stem cells support proliferation and terminal differentiation of B cells.

BACKGROUND: Mesenchymal stem cells (MSC) play important roles in modulating the activities of T lymphocytes, dendritic cells and natural killer cells. These immunoregulatory properties of MSC suggest their therapeutic potential in autoimmune diseases. However, the effects of MSC on B cells are still poorly understood. The present study was designed to investigate the interaction between MSC and B cells both in vitro and in vivo, and to determine the possible mechanism of action. DESIGN AND METHOD: The effect of human umbilical cord mesenchymal stem cells (UC-MSC) on proliferation and differentiation of B-cells were characterized in vitro, and we also tested the immunoregulatory properties of mouse bone marrow MSC (BM-MSC) on T cell dependent and independent antibody production in vivo in mice. RESULTS: Treatment with human UC-MSC resulted in an increase of proliferation, differentiation of B cells into plasma cells and production of antibodies in vitro. Mouse BM-MSC significantly enhanced T cell dependent and independent antibodies production in vivo in mice. PGE2 partially mediated the immunosuppressive activity of human UC-MSC but IL-6 did not regulate this activity. CONCLUSION: MSC promote proliferation and differentiation of B cells in vitro and in vivo partially through PGE2 but not IL-6.

IL-6 production stimulated by CD14(+) monocytes-paracrined IL-1ß does not contribute to the immunosuppressive activity of human umbilical cord mesenchymal stem cells.

BACKGROUND/AIMS: Human umbilical cord mesenchymal stem cells (hUC-MSCs) possess immunosuppressive activities but the mechanisms of such activities are not fully understood. Here, we investigated the role of IL-6, one of the characteristic factors of MSCs, in the immunoregulating effect of hUC-MSCs on CD4(+) T lymphocytes. METHODS: The condition media from human peripheral blood mononuclear cells (hPBMCs) or CD14+/- cell were tested if stimulating IL-6 production by hUC-MSCs. The related signaling pathway of IL-6, and the immunosuppressive activity of IL-6 on CD4(+) T lymphocytes were studied. RESULT: IL-6 production was dramatically increased by hUC-MSCs when co-culturing with resting or activated hPBMCs. CD14(+) monocytes-paracrined IL-1ß promoted the secretion of IL-6 by hUC-MSCs via JNK and NF-κB signaling pathway. Blocking of PGE2 synthesis did not affect the secretion of IL-6, anti-IL-6 antibody was not able to reverse hUC-MSCs-mediated inhibition on CD4(+) T lymphocytes. IL-6 did not mediate the suppressive activity of IL-1ß-hUC-MSCs- PGE2 on CD4(+) T cell. CONCLUSION: CD14(+) monocytes-paracrined IL-1ß promotes IL-6 secretion by hUC-MSCs through activating JNK and NF-κB signaling pathway. However, increased IL-6 production does not contribute to immunosuppressive activity of IL-1ß-hUC-MSCs- PGE2 on CD4(+) T cells.

Cardiac cell therapy: pre-conditioning effects in cell-delivery strategies.

Stem-cell therapy holds great promise for the treatment of ischemic heart disease. However, the benefit of cardiac cell therapy has not yet been proven in long-term clinical trials. Poor engraftment and survival of transplanted cells is one of the major concerns for the successful application of stem cells in cardiac cell therapy. Cell and cardiac pre-conditioning are now being explored as new approaches to support cell survival and enhance the therapeutic efficacy. In this paper, we summarize the state-of-the-art methods of cell delivery and cell survival post-delivery, with a focus on the pre-conditioning approaches that have been attempted to support the survival of transplanted cells.

Immunomodulatory effects of mesenchymal stem cells in a rat corneal allograft rejection model.

Mesenchymal stem cells (MSCs) are promising candidates for immunomodulatory therapy that are currently being tested in several organ transplant rejection models. In this study, we tested the immunomodulatory effects of MSC injection in a rat model of corneal allograft rejection. MSCs were isolated and cultured from bone marrow of Wistar rats. A rat corneal allograft rejection model was established using Wistar rats as donors and Lewis rats as recipients. Lewis rats were randomly separated into 12 groups and treated with MSCs alone or MSCs combined with Cyclosporin A (CsA) at different doses. In MSC-treated rats, the T cell response to ConA was evaluated, Th1/Th2 cytokines produced by T lymphocytes were measured, and the number of CD4+CD25+Foxp3+ regulatory T cells (Treg) was assessed. Results demonstrated that postoperative injection of MSCs prolonged graft survival time. MSCs significantly inhibited proliferation of pathogenic T cells in vitro and prevented T cell response in vivo (p < 0.05). Postoperative injection also reduced Th1 pro-inflammatory cytokines and elevated IL-4 cytokine secretion from T lymphocytes derived from cornea-transplanted rats. In addition, Tregs were upregulated by MSC treatment. Unexpectedly, the application of MSCs combined with low dose CsA therapy (1 mg/kg) accelerated graft rejection compared with postoperative MSC therapy alone. However, when 2 mg/kg CsA was given together with MSCs, graft survival was significantly prolonged. These results suggested that MSCs could exert therapeutic effect against corneal allograft rejection, and further investigation of combined MSC and CsA treatment be required as opposite effects were observed depending on CsA dose.