Notch signaling regulates CXCR4 expression and the migration of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have been used to repair injured tissues through immune-suppression and/or cell replace mechanisms. However, a significant barrier to MSC therapy is insufficient MSC engraftment in injured tissues after systemic administration. Here, we report that cell surface, total protein, and mRNA levels of CXCR4 were significantly increased in MSCs when Notch signaling was interrupted by γ-secretase inhibitor (GSI) or knockout of the transcription factor RBP-J, which mediates signaling from all four mammalian Notch receptors. The GSI-treated or RBP-J deficient MSCs showed stronger migration toward stromal cell-derived factor-1α (SDF-1α) than that of the control. In a mouse hepatic ischemia/reperfusion model, RBP-J deficient MSCs migrated into the injured liver tissues at a significantly higher efficiency than that of the control MSCs. Mice transfused with RBP-J deficient MSCs showed reduced liver damage. Therefore, Notch signaling regulates MSC migration and function, at least partially via the modulation of CXCR4 expression.

The dynamics behavior of Rh nanoclusters on boron nitride sheet.

The configurations and corresponding adsorption energies of Rh(n) (n = 4-13) nanoclusters on the boron nitride sheet are investigated by density functional theory (DFT). We use the force-matching method (FMM) to modify parameters of Morse and Tersoff potential functions. To elucidate the dynamical behaviors of Rh nanoclusters on the boron nitride sheet, molecular dynamics (MD) is applied with modified Morse potential function parameter. Finally, the square displacement (SD) is utilized the dynamics behavior of different size Rh nanoclusters at different temperatures.

Kinetics and mechanisms for the adsorption, dissociation, and diffusion of hydrogen in Ni and Ni/YSZ slabs: a DFT study.

The adsorption, dissociation, and diffusion of hydrogen in Ni(100) and Ni(100)/YSZ(100) slabs with two different interfaces (Ni/cation and Ni/O interface) have been studied by the density functional theory (DFT) with the Perdew-Wang functional. The H(2) molecule is found to preferentially absorb on a Top (T) site with side-on configuration on the Ni(100) surface, while the H-atom is strongly bound at a fcc Hollow (H) site. The barrier for the H(2) dissociation on both surfaces is calculated to be only ~0.1 eV. The potential energy pathways of H diffusion on pure Ni and Ni/YSZ with the two different interfaces are studied. Our calculated results show that the H-atom diffusion occurs via surface path rather than the bulk path. For the bulk path in Ni/YSZ, H-atom migration can occur more readily at the Ni/cation interface compared to the Ni/O interface. The existence of vacancy in the interface region is found to improve the mobility of H-atoms at the interface of Ni/YSZ slab. The rate constants for hydrogen dissociation and diffusion in pure Ni and Ni/YSZ are predicted.

The balance between two isoforms of LEF-1 regulates colon carcinoma growth.

BACKGROUND: Colon cancer is one of the most aggressive human malignancies, with a very poor prognosis. Although it has been suggested that different isoforms of the lymphoid enhancer factor (LEF-1) have opposing biological activities, the biological outcome of aberrant LEF-1 activation in colon cancer is still unclear. The aim of this study was to evaluate the effect of the different LEF-1 phenotypes on the growth of colon carcinoma cell lines. A deeper understanding of these processes might improve the targeted therapies for colon cancer by regulating the expression of LEF-1. METHODS: The role of different isoforms of LEF-1 on the growth of human colon carcinoma cell lines (SW480 and HT-29) was studied using various in vitro and in vivo assays. In vitro proliferation, migration, adhesion and apoptosis of the cells stably transfected of different isoforms of LEF-1 were monitored by MTT assay, carboxyfluorescein diacetate-succinimidyl ester staining, annexin V staining, ECM adhesion assay and transwell assay, respectively. In nude mice, the formation of neovasculature in the tumors formed by our constructed cells was measured by immunohistochemistry. All the data were analyzed using a t test, and data were treated as significant when p < 0.05. RESULTS: Overexpression of truncated LEF-1 (LEF-1-ΔL) in the colon cell lines, SW480 and HT29, inhibited their growth significantly in vitro and in vivo, but the full-length LEF-1 (LEF-1-FL) promoted the proliferation of HT29. Inactivation of Wnt signaling by LEF-1-ΔL reduced the expression of CXCR4 in colon cell lines, which may lead to a decrease in activities such as migration, adhesion and survival. In nude mice, the formation of neovasculature as well as an increase in tumor volume were inhibited by the short isoform of LEF-1. LEF-1-FL, however, caused an increase in all these parameters compared with controls. CONCLUSIONS: These findings suggest that LEF-1 might play an important role in colon carcinogenesis by acting as a regulator. Enhanced expression of LEF-1-FL, which occurs frequently in colon cancer, may be a new target for clinical therapy.

Monocyte to macrophage differentiation-associated (MMD) positively regulates ERK and Akt activation and TNF-α and NO production in macrophages.

Macrophage activation is modulated by both environmental cues and endogenous programs. In the present study, we investigated the role of a PAQR family protein, monocyte to macrophage differentiation-associated (MMD), in macrophage activation and unveiled its underlying molecular mechanism. Our results showed that while MMD expression could be detected in all tissues examined, its expression level is significantly up-regulated upon monocyte differentiation. Within cells, EGFP-MMD fusion protein could be co-localized to endoplasmic reticulum, mitochondria, Golgi apparatus, but not lysosomes and cytoplasm. MMD expression is up-regulated in macrophages after LPS stimulation, and this might be modulated by RBP-J, the critical transcription factor of Notch signaling. Overexpression of MMD in macrophages increased the production of TNF-α and NO upon LPS stimulation. We found that MMD overexpression enhanced ERK1/2 and Akt phosphorylation in macrophages after LPS stimulation. Blocking Erk or Akt by pharmacological agent reduced TNF-α or NO production in MMD-overexpressing macrophages, respectively. These results suggested that MMD modulates TNF-α and NO production in macrophages, and this process might involves Erk or Akt.

The dynamic behavior of ethanol and water mixtures inside an Au nanotube molecule filter.

Molecular dynamics (MD) simulation was used to investigate the behavior of water and ethanol molecules, which were mixed with five water-ethanol weight fractions (100:0, 0:100, 25:75, 50:50, and 75:25) inside the Au nanotube. To investigate the nano-confinement effect on water and ethanol molecules, the data of both molecules were analyzed by the probability of the number H-bonds per water and ethanol molecule and radial density distribution. Our results reveal that the radial density distributions and the number of H-bonds are significantly influenced by the Au nanotube, and the molecules also display different behavior from those in the bulk environment. In addition, the interaction between water molecules and the Au nanotube is stronger than that between ethanol molecules and the Au nanotube, from the profile of radial density distribution. Finally, both the number of H-bonds per water and per ethanol will be affected by the weight fraction, because the H-bond not only forms between the same material, but also between different materials.

Differential expression and clinical significance of COX6C in human diseases.

Mitochondria, independent double-membrane organelles, are intracellular power plants that feed most eukaryotic cells with the ATP produced via the oxidative phosphorylation (OXPHOS). Consistently, cytochrome c oxidase (COX) catalyzes the electron transfer chain's final step. Electrons are transferred from reduced cytochrome c to molecular oxygen and play an indispensable role in oxidative phosphorylation of cells. Cytochrome c oxidase subunit 6c (COX6C) is encoded by the nuclear genome in the ribosome after translation and is transported to mitochondria via different pathways, and eventually forms the COX complex. In recent years, many studies have shown the abnormal level of COX6C in familial hypercholesterolemia, chronic kidney disease, diabetes, breast cancer, prostate cancer, uterine leiomyoma, follicular thyroid cancer, melanoma tissues, and other conditions. Its underlying mechanism may be related to the cellular oxidative phosphorylation pathway in tissue injury disease. Here reviews the varied function of COX6C in non-tumor and tumor diseases.

The transcription factor RBP-J-mediated signaling is essential for dendritic cells to evoke efficient anti-tumor immune responses in mice.

BACKGROUND: Dendritic cells (DCs) are professional antigen presenting cells that initiate specific immune responses against tumor cells. Transcription factor RBP-J-mediated Notch signaling regulates DC genesis, but whether this pathway regulates DC function in anti-tumor immunity remains unclear. In the present work we attempted to identify the role of Notch signaling in DC-mediated anti-tumor immune response. RESULTS: When DCs were co-inoculated together with tumor cells, while the control DCs repressed tumor growth, the RBP-J deficient DCs had lost tumor repression activity. This was most likely due to that DCs with the conditionally ablated RBP-J were unable to evoke anti-tumor immune responses in the solid tumors. Indeed, tumors containing the RBP-J deficient DCs had fewer infiltrating T-cells, B-cells and NK-cells. Similarly, the draining lymph nodes of the tumors with RBP-J-/- DCs were smaller in size, and contained fewer cells of the T, B and NK lineages, as compared with the controls. At the molecular level, the RBP-J deficient DCs expressed lower MHC II, CD80, CD86, and CCR7, resulting in inefficient DC migration and T-cell activation in vitro and in vivo. T-cells stimulated by the RBP-J deficient DCs did not possess efficient cytotoxicity against tumor cells, in contrast to the control DCs. CONCLUSION: The RBP-J-mediated Notch signaling is essential for DC-dependent anti-tumor immune responses. The deficiency of RBP-J impairs the DC-based anti-tumor immunity through affecting series of processes including maturation, migration, antigen presentation and T-cell activation. The Notch signaling pathway might be a target for the establishment of the DC-based anti-tumor immunotherapies.

Disruption of the transcription factor recombination signal-binding protein-Jkappa (RBP-J) leads to veno-occlusive disease and interfered liver regeneration in mice.

UNLABELLED: Liver sinusoid (LS) endothelial cells (LSECs) support hepatocytes in resting livers and proliferate during liver regeneration to revascularize regenerated liver parenchyma. We report that recombination signal-binding protein-Jkappa (RBP-J), the critical transcription factor mediating Notch signaling, regulates both resting and regenerating LSECs. Conditional deletion of RBP-J resulted in LSEC proliferation and a veno-occlusive disease-like phenotype in the liver, as manifested by liver congestion, deposition of fibrin-like materials in LSs, edema in the space of Disse, and increased apoptosis of hepatocytes. Regeneration of liver was remarkably impaired, with reduced LSEC proliferation and destroyed sinusoidal structure. LSEC degeneration was obvious in the regenerating liver of RBP-J-deficient mice, with some LSECs losing cytoplasm, and organelles protruding into the remnant plasma-membrane of LSs to hamper the microcirculation and intensify veno-occlusive disease during liver regeneration. Hepatocytes were also degenerative, as shown by dilated endoplasmic reticulum, decreased proliferation, and increased apoptosis during liver regeneration. Molecular analyses revealed that the dynamic expression of several related molecules-such as vascular endothelial growth factor, vascular endothelial growth factor receptors 1 and 2, interleukin-6, and hepatocyte growth factor-was disturbed. CONCLUSION: Notch/RBP-J signaling may play dual roles in LSECs: in resting liver it represses proliferation, and in regenerating liver it supports proliferation and functional differentiation.

The interfacial behavior of water/PMMA thin film under normal compression.

Molecular dynamics simulation (MD) has been used to investigate the structure property of water/PMMA interface under compression and compression release. A virtual repulsive wall was employed to generate a normal compression strain on the simulation model, leading a compressive system. In order to understand the difference of interfacial phenomenon between the system under strain and under release, the hydrogen bond and density distributions of water and PMMA along the normal direction are calculated. The results show that the hydrogen bond distribution profile of compressive system is different from that of the release system at the same strain. It demonstrates that the characteristic structure of water/PMMA interface under a compression-release cycle is not reversible.

The function of SEC22B and its role in human diseases.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins are a large protein complex that is involved in the membrane fusion in vesicle trafficking, cell growth, cytokinesis, membrane repair, and synaptic transmission. As one of the SNARE proteins, SEC22B functions in membrane fusion of vesicle trafficking between the endoplasmic reticulum and the Golgi apparatus, antigen cross-presentation, secretory autophagy, and other biological processes. However, apart from not being SNARE proteins, there is little knowledge known about its two homologs (SEC22A and SEC22C). SEC22B alterations have been reported in many human diseases, especially, many mutations of SEC22B in human cancers have been detected. In this review, we will introduce the specific functions of SEC22B, and summarize the researches about SEC22B in human cancers and other diseases. These findings have laid the foundation for further studies to clarify the exact mechanism of SEC22B in the pathological process and to seek new therapeutic targets and better treatment strategies.

Endothelial cells promote the proliferation of lymphocytes partly through the Wnt pathway via LEF-1.

The function of T cells and B cells is to recognize specific "non-self" antigens, during a process known as antigen presentation. Once they have identified an invader, the cells generate specific responses that are tailored to maximally eliminate specific pathogens or pathogen-infected cells. Endothelial cells (ECs) can trigger the activation of T cells through their class I and class II MHC molecules. In this study, we examined the effect of ECs on the proliferation of lymphocytes. We report that the proliferation of T and B cells can be improved by interaction with ECs. LEF-1 is one of the main molecular mediators in this process, and the inhibition of LEF-1 induces apoptosis. These results suggest that LEF-1 modulates positively the proliferation of lymphocytes induced by their interaction with ECs.

RBP-J, the transcription factor downstream of Notch receptors, is essential for the maintenance of vascular homeostasis in adult mice.

In adults, angiogenic abnormalities are involved in not only tumor growth but several human inherited diseases as well. It is unclear, however, concerning how the normal vascular structure is maintained and how angiogenesis is initiated in normal adults. Using the Cre-LoxP-mediated conditional gene deletion, we show in the present study that in adult mice disruption of the transcription factor recombination signal-binding protein Jkappa (RBP-J) in endothelial cells strikingly induced spontaneous angiogenesis in multiple tissues, including retina and cornea, as well as in internal organs, such as liver and lung. In a choroidal neovascularization model, which mimics the angiogenic process in tumor growth and age-related macular degeneration, RBP-J deficiency induced a more intensive angiogenic response to injury. This could be transmitted by bone marrow, indicating that RBP-J could modulate bone marrow-derived endothelial progenitor cells in adult angiogenesis. In addition, in the absence of RBP-J, proliferation of endothelial cells increased significantly, leading to accumulative vessel outgrowth. These findings suggest that in adults RBP-J-mediated Notch signaling may play an essential role in the maintenance of vascular homeostasis by repressing endothelial cell proliferation.

Modeling of the polyethylene and poly(L-lactide) triblock copolymer: a dissipative particle dynamics study.

Dissipative particle dynamics (DPD), a mesoscopic simulation approach, has been used to investigate the effect of the arrangement of the microstructure and the effect of the volume fraction on the structural properties of the immiscible polyethylene (PE)/poly(L-lactide) (PLLA) polymer in the triblock copolymer system. In this work, the interaction parameter in DPD simulation, related to the Flory-Huggins interaction parameter chi, is estimated by the calculation of mixing energy for each pair of components in molecular dynamics simulation. The immiscibility property of PE and PLLA polymers induces phase separation and exhibits different architectures at different volume fractions. In order to obtain the structural property, the radius of gyration and the end-to-end distance are used to observe the detailed arrangement of the triblock copolymer. The results show first that the relative volume fractions of PE and PLLA directly affect the bridge and loop fraction, and, second, that whether or not the arrangement is symmetrical or asymmetrical affects the equilibrium structure in the triblock copolymer system. Moreover, as the chain length of the component chains within the PE-PLLA-PE triblock copolymer increase, those component chains become softer; therefore, this directly affects the bridge and loop fraction.

Combined molecular dynamics and dissipative particle dynamics to study of the microstructure of poly(L-lactide)/polyethylene blends.

Different type of polymers miscibility has been induced great interest, owing to its relevance to the understanding of processing and performance properties of blends containing different type of polymers. In this article, we investigate the microstructure of poly(L-lactide) (PLLA)/polyethylene (PE) blends. The simulation method is adopted molecular dynamics and dissipative particle dynamics. The results show that the stable microstructures are type of cylinder and lamellae with volume ratio (VPE/VPLLA = 3/7). Furthermore, the lateral compression test is also used to study the stability of microstructure.

[The distribution and phenotype of bone marrow-derived cells in mice's eyes after induction of choroidal neovascularization by laser photocoagulation].

OBJECTIVE: To investigate the phenotype feature of bone marrow-derived cells in mice's eyes after induction of choroidal neovascularization by laser photocoagulation. METHODS: It was a experimental study. Green fluorescent protein (GFP) chimeric mice were developed by transplanting bone marrow cells from GFP +/+ transgenic mice to adult C57BL/6J mice. The chimeric mice underwent laser rupture of Bruch membrane to induce CNV. Fluorescein fundus angiography and histopathological study were used to confirm the stable formation of CNV. Then the eyes were enucleated and processed for immunofluorescence to detect the distribution and phenotype of GFP + cells. RESULTS: The development of CNV has stabled by the 14th day after lasering. GFP-labelled cells appeared in CNV lesions (including choroid beneath CNV lesion), neurosensory retina over CNV, corneoscleral limbus, ciliary body, optic disc and sclera, retina and choroid distant from CNV. GFP + cells, which were immunoreactive for alphaSMA or CD31, appeared in lesions only. However, F4/80 + green cells can be also detected in neurosensory retina over CNV, corneoscleral limbus and ciliary body. CONCLUSIONS: BMC which differentiated into vascular cells presented in CNV lesions only. Some BMC appearing in other positions might be macrophages or dendritic cells. There may be other functions apart from contributing to choroidal neovascularization for BMC in the eyes.

The dynamic conduct of bone marrow-derived cells in the choroidal neovascularization microenvironment.

PURPOSE: Choroidal neovascularization (CNV) is one of the most frequent causes of severe and progressive vision loss. Prior studies have shown that bone marrow-derived cells (BMCs) play an important role in CNV, indicating that BMCs can be a potential target for inhibiting the development of CNV. It could be helpful for our understanding of CNV to study the dynamic conduct of BMCs in the CNV microenvironment. METHODS: Green fluorescent protein (gfp) chimeric mice were developed by transplanting bone marrow cells from gfp+/+ transgenic mice to adult C57BL/6J mice. The chimeric mice underwent laser rupture of Bruch's membrane to induce CNV and were killed at 1, 2, 3, and 4 weeks after laser injury. The eyes were enucleated and processed for immunofluorescence to detect markers for vascular smooth muscle cells (alpha smooth muscle actin, alpha SMA), endothelial cells (CD31), or macrophages (F4/80) on gfp+ cells. All sections were qualitatively and quantitatively assessed by confocal microscopy. RESULTS: Large number of gfp-labeled cells appeared in the lesions and integrated into CNV. Gfp+ cells, which were immunoreactive for alpha SMA, CD31, or F4/80, can be detected through the whole study. The constituent ratio of those three cell-types in total gfp+ cells in CNV altered as CNV developed. The maximal ratios of CD31-labeled cells and F4/80-labeled cells presented at 2 week, while the ratio of alpha SMA-labeled cells upgraded continuously. CONCLUSIONS: BMCs underwent a serial of changes in position and expression during the progression of CNV. Those changes may result from the interaction between BMCs and the CNV microenvironment.

The blockage of Notch signalling promoted the generation of polymorphonuclear myeloid-derived suppressor cells with lower immunosuppression.

Myeloid-derived suppressor cells (MDSCs) mostly consisting of polymorphonuclear (PMN)-MDSCs and mononuclear MDSCs have been considered to play critical roles in immunosuppression, angiogenesis, invasion and metastases of various tumours. However, it is still unclear the regulated mechanisms underlying the generation and immunosuppression of two major MDSC subsets. Here, we report Notch signalling was inhibited significantly in tumour-bearing mouse MDSCs, in which PMN-MDSCs were the major population. MDSCs without recombination signal binding protein-Jк (RBP-J), the critical transcription factor mediating signalling from all four mammalian Notch receptors, reduced their ability of inhibiting the proliferation and activation of allogenic T cells. RBP-J-deficient MDSCs could not down-regulate the expression of co-stimulation molecules on dendritic cells (DCs). The antigen presentation capacity of DCs co-cultured with RBP-J-deficient MDSCs was not impaired in contrast to controls. Moreover, we show the blockage of Notch signalling could improve the generation of PMN-MDSCs but inhibit the production of mononuclear MDSCs both in vitro and in vivo. Stat3 pathway was suppressed in MDSCs blocked Notch signalling and Stat3 activation by IL-6 could reverse the phenotype and immunosuppression of Notch signalling-deficient MDSCs. Therefore, targeting Notch signalling may be an effective therapeutic strategy in tumour therapy.

[TNF-α stimulates bone marrow mesenchymal stem cell VCAM-1 production by ERK signaling pathway].

This study was aimed to explore the effect of TNF-α on the vascular cell adhesion molecule 1 (VCAM-1) expression of human bone marrow mesenchymal stem cells (BMMSC) and the relationship between this process and ERK signalling pathway. BMMSC were isolated by density gradient centrifugation combined with adherent culture method, and then identified by surface antigen expression and differentiation potential. Flow cytometry was used to detect expression of VCAM-1 on BMMSC exposed to TNF-α at different concentrations, and the effect of ERK inhibitor U0126 on VCAM-1 of BMMSC. ERK signaling pathway activation was analyzed by Western blot. The results showed that BMMSC positively expressed CD29, CD69, CD44, CD105, and negatively expressed CD34, CD45. BMMSC could be induced to differentiate into osteoblasts and adipocytes. Flow cytometry analysis showed that after the TNF-α stimulation, the expression of VCAM-1 on BMMSC increased in a dose-dependent manner. And this increase was inhibited by U0126. TNF-α caused activation of ERK signal pathway, and U0126 suppressed this effect induced by TNF-α. It is concluded that TNF-α can increase expression of VCAM-1 of BMMSC via ERK signaling pathway.

[The relationship of telomere and telomerase activity with outcome of aplastic anemia after immunosuppressive therapy].

OBJECTIVE: To observe the changes of telomere length and telomerase activity in patients with aplastic anemia (AA), and relationship with immunosuppressive therapy (IST) efficacy, to explore the pathogenesis of AA and the role of telomere length in evaluating immunosuppressive therapy efficacy. METHODS: 71 cases of AA patients between September 2010 and March 2013 were enrolled into this study. 3 ml peripheral blood specimens from this cohort of patients were collected to test the telomere length in peripheral blood mononuclear cell (PBMNC) with flow-FISH and detect telomerase activity with TRAP-PCR-ELISA method. RESULTS: Telomere length and age showed negative correlation (b=-0.387, P=0.001) in normal control, NSAA and SAA + VSAA groups, telomere length became shorter with the growth of age, and normal control group telomere length decreased along with the age growth slightly greater than the other two groups (NSAA, SAA+VSAA). Besides the effect of age on telomere length, no significant difference was observed between NSAA and SAA+VSAA groups (P=0.573), and NSAA, SAA+VSAA (30.957 ± 4.502,29.510 ± 5.911)groups were significantly shorter than normal control group (51.086±10.844) (P<0.01). Telomere length in NR group (25.357±4.848)was significantly lower than normal control group (51.086 ± 10.844) (P=0.005), telomere length in CR(32.808 ± 4.685)/PR groups (30.334±4.464) compared with normal control group had no significant difference (P=0.517, P=0.254). Telomere length below 29.21% obviously decreased outcomes of IST. Telomerase activity had significant difference (χ²=20.385, P<0.01). The telomerase activity had no significant difference in terms of age and gender in three groups, multiple comparison found that telomerase activities in SAA + VSAA (0.324±0.178) (P<0.01), and NSAA (0.234±0.175) groups (P=0.002) were significantly higher than normal control group (0.107±0.083). CONCLUSION: Telomere length of PBMNC in AA patients was significantly shortened than normal control group with telomerase activity increased, and telomere shorted more apparently in NR group, these patients should adjust the treatment as early as possible. Telomeres could predict the curative effect of IST.