Liu Yl

CCR7 guides migration of mesenchymal stem cell to secondary lymphoid organs: a novel approach to separate GvHD from GvL effect.

Inefficient homing of systemically infused mesenchymal stem cells (MSCs) limits the efficacy of existing MSC‐based clinical graft‐versus‐host disease (GvHD) therapies. Secondary lymphoid organs (SLOs) are the major niches for generating immune responses or tolerance. MSCs home to a wide range of organs, but rarely to SLOs after intravenous infusion. Thus, we hypothesized that targeted migration of MSCs into SLOs may significantly improve their immunomodulatory effect. Here, chemokine receptor 7 (CCR7) gene, encoding a receptor that specifically guides migration of immune cells into SLOs, was engineered into a murine MSC line C3H10T1/2 by retrovirus transfection system (MSCs/CCR7). We found that infusion of MSCs/CCR7 potently prolonged the survival of GvHD mouse model. The infused MSCs/CCR7 migrate to SLOs, relocate in proximity with T lymphocytes, therefore, potently inhibited their proliferation, activation, and cytotoxicity. Natural killer (NK) cells contribute to the early control of leukemia relapse. Although MSCs/CCR7 inhibited NK cell activity in vitro coculture, they did not impact on the proportion and cytotoxic capacities of NK cells in the peripheral blood of GvHD mice. In an EL4 leukemia cell loaded GvHD model, MSCs/CCR7 infusion preserved the graft‐versus‐leukemia (GvL) effect. In conclusion, this study demonstrates that CCR7 guides migration of MSCs to SLOs and thus highly intensify their in vivo immunomodulatory effect while preserving the GvL activity. This exciting therapeutic strategy may improve the clinical efficacy of MSC based therapy for immune diseases. Stem Cells 2014;32:1890–1903

Electrochemical Discharge Machining Micro-Hole in Stainless Steel with Tool Electrode High-Speed Rotating

Electrochemical discharge machining with high-speed micro-electrode is a micro-machining process based on the fundamental of electrochemical discharge principle. The process has been applied in metal for drilling micro-holes. Drilling of micro-holes in stainless steel is a challenge working. A few qualitative conclusions are obtained by drilling micro-holes in stainless steel by electrochemical discharge machining with high-speed electrode using pure water as electrolyte. An experimental setup was established. A micro-hole was drilled in stainless steel successfully.

Tumor Necrosis Factor-α Alters the Modulatory Effects of Mesenchymal Stem Cells on Osteoclast Formation and Function

Mesenchymal stem cells (MSCs) are characterized by their hematopoiesis-supporting and immunosuppressive capacity, while osteoclasts are main cell components in the endosteal hematopoietic stem cell niche and pivotal players in osteoimmunology. To clarify the association of these 2 kinds of cells, mouse CD11b(+) monocytes were cultured onto MSC layers in the presence or absence of macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL). The results showed that MSCs independently supported osteoclast development and this effect was enhanced by M-CSF and RANKL. Interestingly, tumor necrosis factor-alpha (TNF-alpha)-stimulated MSCs turned to inhibit osteoclast formation and protect tusk slices from osteoclastic resorption. Real-time PCR and ELISA assays demonstrated that osteoprotegerin expression at both mRNA and protein levels in TNF-alpha-stimulated MSCs was up-regulated, at least partially by activating the mitogen-activated protein kinase pathway. Furthermore, TNF-alpha-stimulated MSCs maintained their immunophenotypic, multipotential differentiation and immunosuppressive characteristics. Moreover, MSCs treated with synovial fluid from rheumatoid arthritis patients modulated osteoclast generation in close relation with the TNF-alpha levels. This study suggests that MSCs exhibit dual modulatory function on osteoclasts and the result might shed light on understanding the involvement of MSCs in the inflammatory diseases.

Electrochemical Micromachining of Complex Shapes on Nickel and Nickel-Based Superalloys

This paper proposes a high-precision electrochemical micromachining (EMM) system. By applying nanosecond pulses, workpiece dissolution can be restricted to a very small area around the microelectrode. First, an EMM system that meets the requirements of the EMM process is built. Second, sets of comparative experiments are performed on pure nickel and superalloy plates to study the effects of main machining parameters, e.g., pulse on time, applied voltage, pulse period, and electrode diameters, on side gap. Finally, after the preliminary experiments, complex microshapes with characteristic size of several tens of micrometers are successfully fabricated on the nickel and superalloy plates, thereby demonstrating that EMM is a very promising microfabrication technology.

Restoration of tissue damage, and never activity after hypoxia–ischemia by implantation of peripheral blood mononuclear cells

Hypoxia-ischemia (HI) encephalopathy is a frequent cause of disability and mortality with limited therapeutic options. Here, we collected peripheral blood mononuclear cells (PB-MNCs) from healthy donors and labeled them with CM-DiI before implanting these cells by tail-vein injection into rats at day 3 after hypoxia-ischemia (HI). For immune-suppression the animals received daily injections of cyclosporine throughout the experiment, commencing 24h before cell transplantation. Then we observed the PB-MNCs by fluorescent microscopy, examined motor function of rats by rotarod and cylinder tests, measured the lesion volume using image-pro plus software, and analyzed the apoptosis of neural cells in HI rats by tunnel assay. The results showed PB-MNCs could survive in the brain of hosts, migrate to the damage area and express neural marker. In addition, The HI rats that received PB-MNCs showed a reduction in motor function impairment, lesion volume and neural cell apoptosis. To better understand the mechanism of cell migration, PB-MNCs were also injected into normal rats via tail-vein. The expression of stromal cell-derived factor-1 (SDF-1) in the brain of normal and HI rats was measured by RT- PCR and western-blot, while the response of PB-MNCs in vitro to HI or normal brain extracts were measured by cell migration assay. Collectively these data suggest that the migration of PB-MNCs is directed to the damaged brain through an SDF-1-dependent pathway. Our results suggest that intravenous transplantation of PB-MNCs may be a feasible candidate for HI therapy.

Species-specific mutual regulation of p53 and miR-138 between human, rat and mouse.

In recent years, p53 was identified to regulate the expression of many miRNAs and was also regulated by miRNAs. In this paper, we found that miR-138 showed a pronounced increase after p53 activation in human non-small cell lung cancer (NSCLC) cells, which is mediated by p53 binding sites in the promoter region of its host gene, but this did not happen with rat and mouse cells. More interestingly, we found that p53 could be also regulated by miR-138 in mouse and rat cells, but not in the human NSCLC cells. Our results suggest the existence of species-specific differences of the regulations of miRNA against its targets and the regulations of miRNA itself by other proteins.

MiR-200b modulates the properties of human monocyte-derived dendritic cells by targeting WASF3

AIMS The aim of the study was to explore the effect of miR-200b on the development of human peripheral blood monocyte-deriveddendritic-cell (DC) and its mechanisms. MAIN METHODS Expression levels of miR-200b and its predicted targets were measured by real time-PCR. Protein expression of WASF3 was determined by Western blot and immunohistochemistry. Human peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll-Hypaque density gradient centrifugation from the buffy coat fraction of anticoagulated blood. Monocytes were purified from PBMCs using anti-CD14 microbeads. The immunophenotypes of DCs were tested by flow cytometry. KEY FINDINGS A strong reduction in miR-200b expression was associated with human peripheral blood monocyte-derivedDC differentiation. The overexpression of miR-200b significantly reduced the numbers of protruding veils in mature DCs (mDCs) that are critical for promoting antigen-specificT-cell activation. Further experiments showed that miR-200b could regulate the function of DCs by targeting WASF3, a protein involved in cell movement and invasion. SIGNIFICANCE Our results define an important function of miR-200b in the negative regulation of DC development and provide a potential form of miRNA-mediated cell therapy for diseases that range from auto-immunity to graft-versus-host disease.

Repairing effects of ICAM-1-expressing mesenchymal stem cells in mice with autoimmune thyroiditis

The aim of the present study was to determine the repairing effects of intercellular adhesion molecule (ICAM)-1-expressing mesenchymal stem cells (MSCs) in mice with autoimmune thyroiditis. Following induction of an experimental autoimmune thyroiditis (EAT) model, mice were randomly divided into the following groups (n=10 each): i) Normal control; and experimental groups that were subject to EAT induction, including ii) EAT model; and iii) primary MSC; iv) C3H10T1/2/MSC; v) C3H10T1/2-MIGR1/MSC; and vi) C3H10T1/2-MIGR1-ICAM-1/MSC, which were all administered the relevant cells. MSCs were administered via the caudal vein. A blood sample was harvested from the angular vein of each animal 28 days post-treatment and ELISA was used to determine the serum total triiodothyronine, total thyroxine (T4), thyroid-stimulating hormone (TSH), anti-thyroid peroxidase (TPOAb), anti-thyroid microsomal (TMAb) and anti-thyroglobulin (TGAb) antibodies. Hematoxylin and eosin staining was performed to evaluate injury of the thyroid gland by determining the size of the follicle, inflammatory infiltration, colloidal substance retention and epithelial injury. Reverse transcription-quantitative polymerase chain reaction was performed to determine the mRNA expression of interleukin (IL)-4, IL-10, IL-17 and interferon (INF)-γ. Western blot analysis was performed to determine the expression of p38 mitogen-activated protein kinase (p38) and extracellular signal-regulated kinase (ERK). To observe cellular migration in vivo, mice were divided into the following groups, (n=10 each), which were subject to EAT induction: i) CM-DiI-labeled primary MSC; ii) CM-DiI-labeled C3H10T1/2/MSC; iii) CM-DiI-labeled C3H10T1/2-MIGR1/MSC; and iv) CM-DiI-labeled C3H10T1/2-ICAM-1/MSC, which were all administered the relevant cells via the caudal vein. C3H10T1/2-ICAM-1/MSCs were able to ameliorate the expression of T4, TSH, TPOAb, TMAb and TGAb in vivo, attenuate thyroid follicle injury and decrease the splenic index in mice. They were also able to ameliorate the mRNA expression of IL-4, IL-10, IL-17 and INF-γ, and the modulation of the P38 and ERK-signaling pathways in the mouse spleen. Furthermore, ICAM-1 overexpression was able to modulate the nesting of MSCs in the thyroid gland and lung. These findings suggest that C3H10T1/2-ICAM-1/MSC may affect the differentiation, proliferation and migration of immunocytes through modulating the p38 and ERK signaling pathways, and that ICAM-1 may modulate the immunoregulatory effects of MSCs by affecting the migration of MSCs in vivo.

The Therapeutic Effect of ICAM-1-Overexpressing Mesenchymal Stem Cells on Acute Graft-Versus-Host Disease

Background/Aims: Mesenchymal stem cells (MSCs) do not readily migrate to appropriate sites, and this creates a major obstacle for their use in the treatment of graft-versus-host disease (GVHD). Intercellular adhesion molecule-1 (ICAM-1) can guide the homing of various immune cells to the proper anatomical location within secondary lymphoid organs (SLOs), which are the major niches for generating immune responses or tolerance. MSCs rarely migrate to SLOs after intravenous infusion, and are constitutively low expression of ICAM-1. So in our previous work, ICAM-1 was engineered into a murine MSC line C3H10T1/2 by retrovirus transfection system (ICAM-1MSCs). Here, we hypothesized that ICAM-1highMSCs may significantly improve their immunomodulatory effect. Methods: We used different co-culture methods combined with real-time PCR and flow cytometry to evaluate ICAM-1highMSCs immunomodulatory effect on dendritic cells (DCs) and T cells in vitro and in vivo. MSCs were labeled with carboxyfluorescein diacetate succinimidylester (CFSE) to detect its distribution in mouse model. Results: Our in vitro analyses revealed ICAM-1 MSCs could suppress DCs maturation according to co-culture methods and suppress the T cell immune response according to the mixed lymphocyte response (MLR) and lymphoblast transformation test (LTT) tests. We found that infusion of ICAM-1highMSCs potently prolonged the survival of GVHD mouse model. The infused ICAM-1highMSCs migrate to SLOs in vivo, and suppressed DCs maturation, suppressed CD4+ T cell differentiation to Th1 cells, and increased the ratios of Treg cells. Conclusions: Taken together, these data demonstrate that ICAM-1highMSCs had an enhanced immunosuppressive effect on DCs and T cells, which may help explain the protective effect in a GVHD model. This exciting therapeutic strategy may improve the clinical efficacy of MSC-based therapy for GVHD.