Human amniotic epithelial stem cell is a cell therapy candidate for preventing acute graft-versus-host disease.

Graft-versus-host disease (GVHD), an immunological disorder that arises from donor T cell activation through recognition of host alloantigens, is the major limitation in the application of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Traditional immunosuppressive agents can relieve GVHD, but they induce serious side effects. It is highly required to explore alternative therapeutic strategy. Human amniotic epithelial stem cells (hAESCs) were recently considered as an ideal source for cell therapy with special immune regulatory property. In this study, we evaluated the therapeutic role of hAESCs in the treatment of GVHD, based on our previous developed cGMP-grade hAESCs product. Humanized mouse model of acute GVHD (aGVHD) was established by injection of huPBMCs via the tail vein. For prevention or treatment of aGVHD, hAESCs were injected to the mice on day -1 or on day 7 post-PBMC infusion, respectively. We showed that hAESCs infusion significantly alleviated the disease phenotype, increased the survival rate of aGVHD mice, and ameliorated pathological injuries in aGVHD target organs. We demonstrated that hAESCs directly induced CD4+ T cell polarization, in which Th1 and Th17 subsets were downregulated, and Treg subset was elevated. Correspondingly, the levels of a series of pro-inflammatory cytokines were reduced while the levels of the anti-inflammatory cytokines were upregulated in the presence of hAESCs. We found that hAESCs regulated CD4+ subset polarization in a paracrine mode, in which TGFß and PGE2 were selectively secreted to mediate Treg elevation and Th1/Th17 inhibition, respectively. In addition, transplanted hAESCs preserved the graft-versus-leukemia (GVL) effect by inhibiting leukemia cell growth. More intriguingly, hAESCs infusion in HSCT patients displayed potential anti-GVHD effect with no safety concerns and confirmed the immunoregulatory mechanisms in the preclinical study. We conclude that hAESCs infusion is a promising therapeutic strategy for post-HSCT GVHD without compromising the GVL effect. The clinical trial was registered at www.clinicaltrials.gov as #NCT03764228.

Biological characterization of human amniotic epithelial cells in a serum-free system and their safety evaluation.

Human amniotic epithelial cells (hAECs), derived from the innermost layer of the term placenta closest to the fetus, have been shown to be potential seed cells for allogeneic cell therapy. Previous studies have shown a certain therapeutic effect of hAECs. However, no appropriate isolation and culture system for hAECs has been developed for clinical applications. In the present study, we established a serum-free protocol for hAEC isolation and cultivation, in which better cell growth was observed compared with that in a traditional culture system with serum. In addition to specific expression of cell surface markers (CD29, CD166 and CD90), characterization of the biological features of hAECs revealed expression of the pluripotent markers SSEA4, OCT4 and NANOG, which was greater than that in human mesenchymal stem cells, whereas very low levels of HLA-DR and HLA-DQ were detected, suggesting the weak immunogenicity of hAECs. Intriguingly, CD90+ hAECs were identified as a unique population with a powerful immunoregulatory capacity. In a systemic safety evaluation, intravenous administration of hAEC did not result in hemolytic, allergy, toxicity issues or, more importantly, tumorigenicity. Finally, the therapeutic effect of hAECs was demonstrated in mice with radiation-induced damage. The results revealed a novel function of hAECs in systemic injury recovery. Therefore, the current study provides an applicable and safe strategy for hAEC cell therapy administration in the clinical setting.

CMV-hFasL transgenic mice prevent from experimental autoimmune thyroiditis.

BACKGROUND: Previous studies showed that the role of Fas ligand (FasL) is not consistent in the pathogenesis of autoimmune thyroiditis. This study was designed to investigate the effects of FasL on the pathogenesis of experimental autoimmune thyroiditis (EAT) using CMV-human FasL (hFasL) transgenic mice. METHODS: Transgenic mice ubiquitously expressing hFasL were used as an animal model of EAT by injection of porcine thyroglobulin (pTg). Expression of hFasL was detected by RT-PCR and Western blot. The activity of hFasL transgenic thyrocytes killing Jurket cells was determined. CMV-hFasL transgenic mice and wild type (WT) mice were immunized with pTg and killed 28 days later to evaluate the lymphocytic infiltration of their thyroids. The number of CD4+ and CD8+ lymphocytes from the spleen was detected using FACS. The serum interferon-gamma (IFN-gamma) concentration was measured by ELISA. RESULTS: hFasL expression in the thyroid of CMV-hFasL transgenic mice was confirmed. After co-incubation of Jurket thymocytes with thyroid tissues of CMV-hFasL transgenic mice, the percentage of apoptotic cells in the CMV-hFasL transgenic thyroid group was significantly higher than that of the control WT thyroid group [(23.4 +/- 4.3)% vs (6.6 +/- 2.5)%, P < 0.01]. On day 28 after immunization with pTg, the infiltration index of lymphocytes in thyroids of the CMV-hFasL transgenic mice was significantly lower than that of the WT mice [(1.0 +/- 0.5) vs (2.1 +/- 0.7), P < 0.001]. Moreover, the number of CD4+ and CD8+ lymphocytes of the spleen and serum IFN-gamma concentration were significantly decreased in the CMV-hFasL transgenic mice. CONCLUSIONS: FasL plays an important role in the pathogenesis of autoimmune thyroiditis. Transgenic mice ubiquitously expressing hFasL may strongly inhibit lymphocytic infiltration of the thyroid of EAT and ameliorate the course of this disease.

A20 overexpression under control of mouse osteocalcin promoter in MC3T3-E1 cells inhibited tumor necrosis factor-alpha-induced apoptosis.

AIM: To construct an A20 expression vector under the control of mouse osteocalcin promoter (OC-A20), and investigate osteoblastic MC3T3-E1 cell line, which stably overexpresses A20 protein prevented tumor necrosis factor (TNF)-alpha-induced apoptosis. METHODS: OC-A20 vector was constructed by fusing a fragment of the mouse osteocalcin gene-2 promoter with human A20 complementary DNA. Then the mouse MC3T3-E1 cell line, stably transfected by A20, was established. The expression of A20 mRNA and A20 protein in the cells were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis, respectively. To determine the specificity of A20 expression in osteoblast, the mouse osteoblastic MC3T3-E1 cell line and mouse embryo fibroblast NIH3T3 cell line were transiently transfected with OC-A20. The anti-apoptotic role of A20 in MC3T3-E1 cells was determined by Flow cytometric analysis (FACS), terminal dUTP nick endo-labeling (TUNEL) and DNA gel electrophoresis analysis (DNA Ladder), respectively. RESULTS: Weak A20 expression was found in MC3T3-E1 cells with the primers of mouse A20. A20 mRNA and A20 protein expression were identified in MC3T3-E1 cells transfected with OC-A20 using RT-PCR and Western blot analysis. Only A20 mRNA expression was found in MC3T3-E1 cell after MC3T3-E1 cells and NIH3T3 cells were transient transfected with OC-A20. A decrease obviously occurred in the rate of apoptosis in the OC-A20 group compared with the empty vector (pcDNA3) group by FACS (P< 0.001). A significant increase in TUNEL positive staining was found in the pcDNA group compared with OC-A20 group (P< 0.001). Simultaneously, similar effects were demonstrated in DNA gel electrophoresis analysis. CONCLUSION: We constructed an osteoblast-specific expression vector that expressed A20 protein in MC3T3-E1 cells and confirmed that A20 protects osteoblast against TNF-alpha-induced apoptosis.

Antiapoptotic effect both in vivo and in vitro of A20 gene when transfected into rat hippocampal neurons.

AIM: To evaluate the antiapoptotic effect of the A20 gene in primary hippocampal neurons both in vivo and in vitro. METHODS: Primary hippocampal neurons in embryonic day 18 (E18) rats were transfected with the A20 gene by using the new Nucleofector electroporation transfection method. We then examined, whether A20-neurons possessed anti-apoptotic abilities after TNF-alpha stimulation in vitro. A20-neurons and pcDNA3-neurons were transplanted into the penumbra of the brains of rats that had been subjected to 90-min of ischemia induced by left middle cerebral artery occlusion (MCAO). RESULTS: A20-neurons resisted TNF-alpha induced apoptosis in vitro. The apoptosis rate of neurons overexpressing A20 (28.46%+/-3.87%) was lower than that in neurons transfected with pcDNA3 (53.06%+/-5.36%). More A20-neurons survived in the penumbra both 3-d and 7-d after transplantation than did sham pcDNA3 neurons. CONCLUSION: The novel function of A20 may make it a potential targets for the gene therapy for neurological diseases.

Human alpha galactosidase and alpha 1,2 fucosyltransferase concordantly inhibit xenoreactivity of NIH 3T3 cells with human serum.

AIM: To study the influence of the expression of human alpha galactosidase and alpha1,2 fucosyltransferase on Gal alpha 1,3 Gal and consequent xenoreactivity in NIH3T3 cells. METHODS: The expression levels of G antigen and H antigen and binding of human natural antibodies (IgG and IgM) and complement (C3c) to NIH3T3 cells were analyzed by flow cytometry. Western blot was employed to further determine the expression of glycoproteins of G antigen. Cytolysis assay with normal human serum was performed by MTT assay. RESULTS: Western blot showed that glycoproteins with molecular weight of 107 kDa, 98 kDa, 88 kDa, 56 kDa, 40 kDa, and 37 kDa were inhibited and even abrogated totally in alpha galactosidase transfectants and alpha 1,2 fucosyltransferase transfectants. The combined transfection of the two enzymes led to a much stronger inhibition of the glycoproteins. The binding of GS-IB4 was decreased by 57.4 % in alpha galactosidase transfectants, 28.8 % in alpha 1,2 fucosyltransferase transfectants, and 72.1 % in combined transfectants, respectively. In contrast, UEA-1 binding was increased about 6.7-fold, 6.0-fold, and 8.0-fold respectively. The xenoreactivity with human IgG was also reduced by 61.4 %, 67.0 %, and 73.4 %, respectively in the three kinds of transfectants. The resistance to cytolysis mediated by human serum was enhanced by 42.4 % in alpha galactosidase transfectants, 51.9 % in alpha 1,2 fucosyltranferase, and even 65.5 % in the combined transfectants. CONCLUSION: Although alpha galactosidase and alpha 1,2 fucosyltransferase had different biochemical properties, they could inhibit the expression of Gal alpha 1,3 Gal synergistically, leading to stronger resistance of xenograft against cytolysis.

Expression of human alpha-galactosidase leads to reduction of major xenoepitope Galalpha(1,3) Gal in NIH 3T3 cell.

AIM: To examine the effects of the expression of alpha-galactosidase on the expression of the major xenoepitope Galalpha(1,3) Gal (G antigen) in NIH 3T3 cell. METHODS: The expression levels of G antigen and H antigen and binding of human natural antibodies (IgG and IgM) and complement (C3c) to NIH 3T3 cells were analyzed by flow cytometry. Western blot was employed to further determine the expression of glycoproteins of G antigen. Cytolysis assay with normal human serum was performed by MTT assay. RESULTS: In transfectants, Western blot showed that the binding of human IgG to glycosylated proteins located on the cell membrane was decreased, even abrogated totally. Together with the reduced binding of Gs-IB4 (Griffonia simplicifolia) to transfectants, the stable expression of human alpha-galactosidase effectively inhibited Galalpha(1,3) Gal, Gal epitope synthesis in NIH 3T3 cell. As a result, the xenoreactivities of human IgG, IgM, and C3c were reduced by 73.4 %, 22.3 % and 47.9 %, respectively, while the cell lysis mediated by human XNA and complements was decreased by 42.4 %. CONCLUSION: The stable expression of human alpha-galactosidase in NIH 3T3 cell strongly inhibits the expression of Gal epitopes, resulting in abrupt reduction in xenorejection induced by human serum.

Direct transfer of A20 gene into pancreas protected mice from streptozotocin-induced diabetes.

AIM: To investigate the efficiency of transfer of A20 gene into pancreas against STZ-induced diabetes. METHODS: PVP-plasmid mixture was directly transferred into the pancreatic parenchyma 2 d before STZ injection. The uptake of plasmid pcDNA3-LacZ or pcDNA3-A20 was detected by PCR and the expression of LacZ was confirmed by histological analysis with X-gal. A20 expression in the pancreas of pcDNA3-A20 transgenic mice was measured by RT-PCR and Western blots. Urine amylase, NO generation, and histological examination were examined. RESULTS: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma increased urine amylase concentration 16 h after operation and reversed it to nearly normal 36 h later. On d 33 LacZ expression could be found in spleen, duodenum, and islets. The development of diabetes was prevented by direct A20 gene transferring into the pancreas and A20-mediated protection was correlated with suppression of NO production. The insulitis was ameliorated in A20-treated mice. CONCLUSION: Injection of PVP-plasmid mixture directly into the pancreatic parenchyma led to target gene expression in islets. Direct transfer of A20 gene into the pancreas protected mice from STZ-induced diabetes.

CMV-hFasL transgenic mice are sensitive to low doses of streptozotocin-induced type I diabetes mellitus.

AIM: To investigate the role of Fas-FasL pathway in the pathogenesis of streptozotocin (STZ)-induced type I diabetes mellitus. METHODS: Low dose injections of STZ were used to induce type I diabetes mellitus in the CMV-hFasL transgenic mice. Blood glucose concentration was measured with Glucotrand Plus blood glucose test strips. Expression of hFasL was detected by RT-PCR and Western blotting. The severity of insulitis was determined by histological examination. Expressions of IL-1beta and TNF-alpha mRNA in the pancreas were detected by semi-quantitative RT-PCR analysis. Fas expression in apoptotic RIN-5F cells was also confirmed by RT-PCR in vitro. RESULTS: hFasL was expressed in the islets of CMV-hFasL transgenic mice. The transgenic mice were sensitive to diabetic induction than the control WT mice. IL-1beta and TNF-alpha expressions in the pancreas of CMV-hFasL transgenic mice were far more than that in WT mice. We also found STZ and IL-1beta could both induce higher expression of Fas in RIN-5F. The combining of Fas-FasL could lead to the apoptosis of beta cells in the CMV-hFasL transgenic mice. CONCLUSION: Fas-FasL interaction plays a significant role in the pathogenic mechanism of type I diabetes mellitus.

Gene therapy of experimental autoimmune thyroiditis mice by in vivo administration of plasmid DNA coding for human interleukin-10.

AIM: To investigate the effect of interleukin-10 (IL-10) gene on experimental autoimmune thyroiditis mice. METHODS: Mice were immunized to induce autoimmune thyroiditis with porcine thyroglobulin (pTg), and thyroids of mice were injected with IL-10 DNA. On d 28 after immunization with pTg, mRNA expression of IL-10 in thyroid glands was detected and thyroid specimens were histopathological studied. RESULTS: The mRNA expression of IL-10 was detected in thyroid glands on d 7 and 14 after injection of IL-10 plasmid DNA or on COS-7 cells 48 h after IL-10 plasmid DNA transfection. In addition, hIL-10 levels in culture media significantly increased 48 h and 72 h after IL-10 plasmid DNA transfection. Infiltration index of lymphocytes (1.1+/-0.4) in thyroids of IL-10-treated mice was significantly lower than that of pcDNA3-null-treated mice (2.2+/-0.5) (P<0.01). Compared with pcDNA3-null control mice, IL-10-treated mice had lower levels of serum IFN-gamma (P<0.01). CONCLUSION: The direct injection of DNA expression vectors encoding IL-10 into thyroid significantly inhibited development of lymphocytic infiltration of thyroid of autoimmune thyroiditis mice, and alleviated the progression of this disease.

Intramuscular injection of interleukin-10 plasmid DNA prevented autoimmune diabetes in mice.

AIM: To investigate the effect of plasmid coding interleukin-10 (IL-10) DNA on the development of autoimmune diabetes induced by multiple low doses of streptozotocin (STZ) in mice. METHODS: Injection of STZ (40 mg/kg, i.p.) was given daily for five consecutive days. pcDNA3-IL-10 plasmid (IL-10-treated group) or pcDNA3-null plasmid (pcDNA3-null-treated group) (100 microg DNA once a day) were injected into skeletal muscles of mice on d 1 and d 14. Blood glucose concentration was measured. After mice were killed on d 28, serum IFN-gamma level was measured by ELISA, and pancreatic IL-1beta and TNF-alpha mRNA expression was detected by semi-quantitative reverse-transcription PCR (RT-PCR). The number of CD4+ and CD8+ lymphocytes from spleen was detected using FACS. In addition, pancreatic histology was measured for determination of insulitis grades. RESULTS: Treatment with pcDNA3-IL-10 resulted in the retention and expression of the vector in skeletal muscle, associated with a considerable elevation in the plasma level of IL-10, which was not observed in pcDNA3-null-treated mice. In IL-10-treated diabetic mice induced by STZ, delay-type hypersensitivity responses were suppressed and the glucose level was greatly lower on d 14, 21, and 28 than pcDNA3-null-treated group (P<0.05 or P<0.01). On d 21 and 28 the incidence of diabetes was 33.3% and 40.0%, respectively, which was markedly lower than that of pcDNA3-null-treated group (P<0.05). In IL-10-treated mice pancreatic IL-1beta and TNF-alpha mRNA expression was depressed, and serum IFN-gamma concentration and the number of spleen CD4+ or CD8+ lymphocytes were decreased on d 28. The insulitis grades of IL-10-treated mice were lower than that of pcDNA3-null-treated group (P<0.01). CONCLUSION: Systemic administration of IL-10 plasmid DNA can alleviate insulitis of experimental autoimmune diabetes in mice and reduce incidence of diabetes.