Xiang-Qing Zhu

TRANSIENT IN VITRO EPIGENETIC REPROGRAMMING OF SKIN FIBROBLASTS INTO MULTIPOTENT CELLS

Multipotent stem cells have the potential to establish a new field of promising regenerative medicine to treat tissue damage, genetic disorders, and degenerative diseases. However, limited resource of stem cells has turned to be an evitable obstacle in clinical applications. We utilized a simple in vitro epigenetic reprogramming approach to convert skin fibroblasts into multipotent cells. After transient reprogramming, stem cell markers, including Oct4 and Nanog, became activated in the treated cells. The reprogrammed cells were multipotent as demonstrated by their ability to differentiate into a variety of cells and to form teratomas. Genomic imprinting of insulin-like growth factor II (Igf2) and H19 was not affected by this short period of cell reprogramming. This study may provide an alternative strategy to efficiently generate patient-specific stem cells for basic and clinical research, solving major hurdles of virally-induced pluripotent stem (iPS) cells that entail the potential risks of mutation, gene instability, and malignancy.

Irisin Increased the Number and Improved the Function of Endothelial Progenitor Cells in Diabetes Mellitus Mice

Abstract: The dysfunction of endothelial progenitor cells (EPCs) was found to be associated with vascular complications in diabetes mellitus (DM) patients. Previous studies found that regular exercise could improve the function of EPCs in DM patients, but the underling mechanism was unclear. Irisin, a newly identified myokine, was induced by exercise and has been demonstrated to mediate some of the positive effects of exercise. In this study, we hypothesize that irisin may have direct effects on EPC function in DM mice. These data showed for the first time that irisin increased the number of EPCs in peripheral blood of DM mice and improved the function of EPCs derived from DM mice bone marrow. The mechanism for the effect of irisin is related to the PI3K/Akt/eNOS pathway. Furthermore, irisin was demonstrated to improve endothelial repair in DM mice that received EPC transplants after carotid artery injury. The results of this study indicate a novel effect of irisin in regulating the number and function of EPCs via the PI3K/Akt/eNOS pathway, suggesting a potential for the administration of exogenous irisin as a succedaneum to improve EPC function in diabetic patients who fail to achieve such improvements through regular exercise.

Chronic Toxicity Test in Cynomolgus Monkeys For 98 Days with Repeated Intravenous Infusion of Cynomolgus Umbilical Cord Mesenchymal Stem Cells

Background/Aims: Stem cell-based therapy is attractive in many clinical studies, but current data on the safety of stem cell applications remains inadequate. This study observed the safety, immunological effect of cynomolgus monkey umbilical cord mesenchymal stem cells (mUC-MSCs) injected into cynomolgus monkeys, in order to evaluate the safety of human umbilical cord mesenchymal stem cells (hUC-MSCs) prepared for human clinical application. Methods: Eighteen cynomolgus monkeys were divided into three groups. Group 1 is control group, Group 2 is low-dose group, Group 3 is high-dose group. After repeated administrations of mUC-MSCs, cynomolgus monkeys were observed for possible toxic reactions. Results: During the experiment, no animal died. There were no toxicological abnormalities in body weight, body temperature, electrocardiogram, coagulation and pathology. In the groups 2 and 3, AST and CK transiently increased, and serum inorganic P slightly decreased. All animals were able to recover at 28 days after the infusion was stopped. In the groups 2 and 3, CD3+ and IL-6 levels significantly increased, and recovery was after 28 days of infusion. There were no obvious pathological changes associated with the infusion of cells in the general and microscopic examinations. Conclusions: The safe dosage of repeated intravenous infusion of mUC-MSCs in cynomolgus monkeys is 1.0 × 107/kg, which is 10 times of that in clinical human use.

Converting skin fibroblasts into hepatic-like cells by transient programming

Transplantation of hepatocytes is a promising therapy for end‐stage liver disease, but the availability of functional cells currently precludes its clinical application. We now report a simple transient reprogramming approach to convert fibroblasts into hepatic‐like cells. Human skin fibroblasts were treated with fish egg extracts to become the transiently remodeled cells (TRCs). After infected with retroviral EGFP, they were directly injected into the fetal monkey liver, where they underwent in situ differentiation in the hepatic niche. The hepatic‐like cells were functional as shown by the synthesis of hepatic markers in vivo, including albumin, cytokeratin‐18, and hepatic serum antigen. Similarly, when implanted in the mouse liver, the TRCs were differentiated into hepatic‐like cells that synthesize albumin and CK18 and became completely integrated into the liver parenchyma. The potency of TRCs was mechanistically related to the activation of several signal pathways, which reactivate endogenous genes related to cell potency. This study demonstrates the feasibility of a simple and inexpensive epigenetic remodeling approach to convert human fibroblasts into therapeutic hepatic‐like cells for the treatment of end‐stage liver disease. J. Cell. Biochem. 117: 589–598, 2016.

In vitro and in vivo analysis of human fibroblast reprogramming and multipotency.

Abstract Multipotent stem cells have potential therapeutic roles in the treatment of Duchenne muscular dystrophy (DMD). However, the limited access to stem cell sources restricts their clinical application. To address this issue, we established a simple in vitro epigenetic reprogramming technique in which skin fibroblasts are induced to dedifferentiate into multipotent cells. In this study, human fibroblasts were isolated from circumcised adult foreskin and were reprogrammed by co-culture for 72 h with fish oocyte extract (FOE) in serum-free medium. The cells were then observed and analyzed by immunofluorescence staining, flow cytometry and in vitro differentiation assays. Then FOE-treated human fibroblasts were transplanted by tail vein injection into irradiated mdx mice, an animal model of DMD. Two months after injection, the therapeutic effects of FOE-treated fibroblasts on mdx skeletal muscle were evaluated by serum creatine kinase (CK) activity measurements and by immunostaining and RT-PCR of human dystrophin expression. The results indicated that the reprogrammed fibroblasts expressed higher levels of the pluripotent antigen markers SSEA-4, Nanog and Oct-4, and were able to differentiate in vitro into adipogenic cells, osteoblastic cells, and myotube-like cells. Tail vein injection of FOE-treated fibroblasts into irradiated mdx mice slightly reduced serum CK activity and the percentage of centrally nucleated myofibers two months after cell transplantation. Furthermore, we confirmed human dystrophin protein and mRNA expression in mdx mouse skeletal muscle. These data demonstrated that FOE-treated fibroblasts were multipotent and could integrate into mdx mouse myofibers through the vasculature.

Systemic delivery of human bone marrow embryonic-like stem cells improves motor function of severely affected dystrophin/utrophin–deficient mice

BACKGROUND AIMS Embryonic-like stem cells (ELSCs) express embryonic stem cell-specific marker genes, such as SSEA-4, Oct-4 and Nanog, and can be induced to differentiate into cells of all 3 germ layers. Our preliminary data showed that ELSCs isolated from human bone marrow express multipotent antigen markers and differentiate into multinucleated myotube-like cells more efficiently than do mesenchymal stromal cells (MSCs) isolated from the same source. We investigated the therapeutic effect of ELSCs in dystrophin/utrophin double knock-out (dko) mice, one of the Duchenne muscular dystrophy animal models, by systemically transplanting them through tail-vein injection. METHODS ELSCs and MSCs were both isolated from human bone marrow. Two months after equal amounts of ELSCs or MSCs were injected through tail-vein injection, we evaluated skeletal muscle motor function and serum creatine kinase activity and measured dystrophin expression by means of immunostaining, Western blotting and semi-quantitative reverse transcriptase-polymerase chain reaction. RESULTS ELSCs positive for Oct-4 and Nanog-3 expressed higher levels of SSEA-4, FZD-9 and CD105 and were induced to differentiate into myotube-like cells more efficiently than did MSCs in vitro. Transplantation of ELSCs through the tail vein improved motor function and decreased serum creatine kinase activity at 2 months after cell transplantation. In addition, dystrophin protein and messenger RNA were upregulated and the skeletal muscle histology was improved in these dko mice transplanted with ELSCs. CONCLUSIONS ELSCs could be more efficiently induced to differentiate into myotubes than were MSCs in vitro, and systematically transplanting ELSCs improved muscle motor function and muscle histology in dko mice.

Induced autologous stem cell transplantation for treatment of rabbit type 1 diabetes.

We have examined the effects of induced autologous stem cells on blood sugar levels in a rabbit model of type 1 diabetes. Rabbit skin fibroblasts were induced to dedifferentiate into multipotent stem cells, and were transplanted into the treatment group via the pancreatic artery. After the fibroblasts had been induced for 72 h, some of them became multipotent stem cells. Four weeks after cell transplantation, blood glucose levels of the induced stem cell treatment group were significantly lower. The plasma insulin and plasma C‐peptide levels of the treated group were significantly increased (P < 0.05). The shape and number of islets was different. In the control group, induced cell treatment group and non‐induced cell treatment group. In the control group, islet β‐cell nucleoli were obvious, and cell volumes were larger with more abundant cytoplasm. The rough endoplasmic reticulum was well‐developed and a large number of secretory granules could be seen within the cytoplasm. In the induced cell treatment group, islet β cells were scattered, and their nuclei were oval and slightly irregular in shape. The cytoplasm of these cells contained a nearly normal number of secretory granules. In the non‐induced cell treatment group, islet β‐cells were atrophied and cell volumes were reduced. Cytoplasmic endocrine granules were significantly reduced or absent. In conclusion, treatment with induced multipotent stem cells can reduce blood sugar levels, improve islet cell function, and repair damaged pancreas in a rabbit model of type 1 diabetes.

Efficacy and mechanisms underlying the effects of allogeneic umbilical cord mesenchymal stem cell transplantation on acute radiation injury in tree shrews

Umbilical cord mesenchymal stem cells (UC-MSCs) exert strong immunomodulatory effects and can repair organs. However, their roles in radiation injury remain unclear. We show that in tree shrews with acute radiation injury, injected UC-MSCs significantly improved survival rates, reduced lung inflammation and apoptosis, prevented pulmonary fibrotic processes, recovered hematopoiesis, and increased blood counts. A protein microarray analysis showed that serum levels of the anti-inflammatory cytokines IL-10 and IL-13 and the growth factors BMP-5, BMP-7, HGF, insulin, NT-4, VEGFR3, and SCF were significantly higher, while those of the inflammatory cytokines IL-2, TIMP-2, TNF-α, IFN-γ, IL-1ra, and IL-8 and the fibrosis-related factors PDGF-BB, PDGF-AA, TGF-β1, IGFBP-2, and IGFBP-4 were significantly lower in UC-MSC-injected animals. A transcriptome analysis of PBMCs showed that the mRNA expression of C1q was upregulated, while that of HLA-DP was downregulated after UC-MSC injection. These results confirm the immunohistochemistry results. eGFP-labeled UC-MSCs were traced in vivo and found in the heart, liver, spleen, lungs, kidneys, thymus, small intestine and bone marrow. Our findings suggest that UC-MSC transplantation may be a novel therapeutic approach for treating acute radiation injury.

Reprogrammed Peripheral Blood Mononuclear Cells are Able to Survive Longer in Irradiated Female Mice

Induced multipotent stem (iMS) cells are originated from somatic cells and become multipotent by genetic and/or epigenetic modifications. Previous studies have shown that the fish oocytes extracts (FOE) can induce skin fibroblast cells into iMS cells. In this study, we aim to determine whether FOE can similarly induce mouse peripheral blood mononuclear cells (PBMCs) into the iMS state and if so, whether they can survive longer when they are transplanted into the irradiation female mice. PBMCs of GFP-transgenic male mice were cultured and transiently reprogrammed by FOE. They were deemed reaching the iMS state after detection of expression of stem cell markers. The iMS-like PBMCs were transplanted into female C57BL mice by tail vein injection. The spleen wet weights as well as numbers of colonies of the recipient mice were examined. The results showed the spleen wet weights and numbers of spleen colonies of FOE-induced group were all significantly higher than those of the non-induced group and negative control group. On day 90 after transplantation, FISH analysis detected the presence of Y chromosome in the induced group, but not of the other groups. The current findings demonstrate that FOE-induced PBMCs are able to survive longer in irradiated female mice.