[Relationship of telomere length, mitochondrial DNA copy number of peripheral blood with hypertension in coal miners].

Objective: To explore the relationship of telomere length, mitochondrial DNA copy number of peripheral blood with hypertension and the interaction between telomere length and mtDNA-CN on hypertension in coal miners. Methods: A case control study was conducted in a coal mine of Shanxi province from July to December of 2013, in which 325 healthy workers were selected as the control group and 378 workers with hypertension as the case group. The information about general demographic characteristics and life behavior habits of the subjects were collected through questionnaire. Levels of telomere length and mtDNA-CN in peripheral blood were detected by real-time PCR. Unconditional logistic regression was used to examine the association between hypertension and telomere length, mtDNA-CN. The interaction test between telomere length and mtDNA-CN on hypertension was performed by adding the interaction term in the corresponding model. Results: The mean telomere length of the workers in the case group was (1.50±0.55) kb, and that of the control group was (2.01±0.62) kb, the difference between two groups was significant (t=11.68, P<0.001). The correlation analysis showed that telomere length was positively correlated with mtDNA-CN (r=0.157, P=0.002) in the case group. Multivariate analysis showed that telomere length (OR=4.408, 95%CI: 3.012-6.452), age (OR=0.417, 95%CI: 0.284-0.613), BMI (OR=1.357, 95%CI: 1.162-1.584), monthly household income level (OR=0.656, 95%CI: 0.553-0.778) and work duration (OR=1.249, 95%CI: 1.100-1.417) were influencing factors of hypertension. The multiply interaction between telomere length and mtDNA-CN was significant on hypertension (OR=1.267, 95%CI: 1.094-1.468). Conclusions: The results suggest shorter telomere length is a risk factor of hypertension. There is a multiply interaction between telomere length and mtDNA-CN on hypertension. However, the association between mtDNA-CN and hypertension was not found.

New insights into the heterogeneity and functional diversity of human mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are being tested in several biological systems and clinical settings with the aim of exploring their therapeutic potentials for a variety of diseases. MSCs are also known to be heterogeneous populations with variable functions. In the context of this multidimensional complexity, a recurrent question is what source or population of MSCs is suitable for specific clinical indications. Here, we reported that the biological features of MSCs varied with the individual donor, the tissue source, the culture condition and the subpopulations. Placental chorionic villi (CV) derived MSCs exhibited superior activities of immunomodulation and pro-angiogenesis compared to MSCs derived from bone marrow (BM), adipose and umbilical cord (UC). We identified a subpopulation of CD106(VCAM-1)+MSCs, which are present richly in placental CV, moderately in BM, and lowly in adipose and UC. The CD106+MSCs possess significantly increased immunomodutory and pro-angiogenic activities compared to CD106-MSCs. Analysis of gene expression and cytokine secretion revealed that CD106+MSCs highly expressed several immnumodulatory and pro-angiogenic cytokines. Our data offer new insights on the identification and selection of suitable source or population of MSCs for clinical applications. Further efforts should be concentrated on standardizing methods which will ultimately allow the validation of MSC products with defined biomarkers as predictive of potency in suitable pre-clinical models and clinical settings.

Long-term cultured mesenchymal stem cells frequently develop genomic mutations but do not undergo malignant transformation.

Cultured human umbilical cord mesenchymal stem cells (hUC-MSCs) are being tested in several clinical trials and encouraging outcomes have been observed. To determine whether in vitro expansion influences the genomic stability of hUC-MSCs, we maintained nine hUC-MSC clones in long-term culture and comparatively analyzed them at early and late passages. All of the clones senesced in culture, exhibiting decreased telomerase activity and shortened telomeres. Two clones showed no DNA copy number variations (CNVs) at passage 30 (P30). Seven clones had ≥1 CNVs at P30 compared with P3, and one of these clones appeared trisomic chromosome 10 at the late passage. No tumor developed in immunodeficient mice injected with hUC-MSCs, regardless of whether the cells had CNVs at the late passage. mRNA-Seq analysis indicated that pathways of cell cycle control and DNA damage response were downregulated during in vitro culture in hUC-MSC clones that showed genomic instability, but the same pathways were upregulated in the clones with good genomic stability. These results demonstrated that hUC-MSCs can be cultured for many passages and attain a large number of cells, but most of the cultured hUC-MSCs develop genomic alterations. Although hUC-MSCs with genomic alterations do not undergo malignant transformation, periodic genomic monitoring and donor management focusing on genomic stability are recommended before these cells are used for clinical applications.

The effect of mesenchymal stem cells on dynamic changes of T cell subsets in experimental autoimmune uveoretinitis.

Mesenchymal stem cells (MSCs) are being explored extensively as a promising treatment for autoimmune diseases. We have recently reported that MSCs could ameliorate experimental autoimmune uveoretinitis (EAU) in rats. In this study, we examined further the effects of MSCs on the dynamics of T cell subsets in both eye and spleen and their cytokine production during the course of EAU. We focused on when and where the MSCs had inhibitory effects on T helper type 1 (Th1) and Th17 cells and how long the inhibitory effect lasted, in order to provide more mechanistic evidence for MSCs on the treatment of uveitis. Compared to the control group, administration of MSCs decreased the production of Th1 and Th17 cytokines significantly, while the production of Th2 and regulatory T cell (T(reg)) cytokines [interleukin (IL)-10 and transforming growth factor (TGF)-ß] was elevated during the entire course of EAU. Correspondingly, the dynamic levels of IL-17 in the aqueous humour (AqH) were reduced in MSC-treated rats. Moreover, the ratio of Th17/T(reg) cells in both spleen and eye was decreased. These results provide powerful evidence that MSCs can regulate negatively both Th1 and Th17 responses and restore the balance of Th17/T(regs) in the whole course of EAU, which is important for the regression of the disease.

Interleukin-27 as a negative regulator of human neutrophil function.

Interleukin-27 (IL-27) is a novel cytokine of the IL-6/12 family with a broad range of immune regulation properties, which has been considered as a potential therapeutic agent for immune diseases and cancers. However, little is known about the effect of IL-27 on human neutrophils before its clinical administration. In this study, we investigated the effects of IL-27 on human neutrophil functions including adhesion, reactive oxygen species (ROS)/cytotoxic granule components production, inflammatory cytokines production, major histocompatibility complex (MHC) molecules expression and neutrophils' survival. We showed that IL-27 receptor complex, WSX-1/TCCR and gp130, is constitutively expressed on human neutrophils. In vitro, IL-27 suppressed neutrophil adhesion in response to fMLP, which might depend on the down-regulation of Mac-1. IL-27 also suppressed lipopolysaccharide-induced ROS production and attenuated cytotoxic granule components production in the cytoplasm of human neutrophils. In addition, IL-27 enhanced the production of IL-1ß but not TNF-α from neutrophils. However, IL-27 failed to regulate the expression of MHC molecules and the survival of human neutrophils. In conclusion, our data demonstrate that IL-27 mainly down-modulates human neutrophil function, which might extend our understanding of the role of IL-27 in the innate immune response.

Therapeutic potential of human umbilical cord-derived stem cells in ischemic diseases.

Recent advances suggest human umbilical cord is a new source for stem cells. Our laboratory has established a method to readily isolate and expand stem cells from human umbilical cord tissues. The aim of this study was to investigate the therapeutic potential of human umbilical cord-derived stem (UCDS) cells in ischemic diseases. The UCDS cells were characterized by flow cytometry and differentiation into osteogenic and adipogenic cells. Unilateral hind limb ischemia was surgically induced by femoral artery ligation in nude mice. The animals were intramuscularly injected with 10(6) UCDS cells or control phosphate-buffered saline. Blood perfusion of ischemic limbs was detected by laser Doppler perfusion imaging. Transplantation of UCDS cells to the ischemic limbs of nude mice significantly improved the blood flow to the affected limbs. Thus, transplantation of UCDS cells may potentially be a promising treatment for human ischemic diseases.

Therapeutic neovascularization for peripheral arterial diseases: advances and perspectives.

Recently, with the better understanding of the mechanisms of neovascularization, many new therapeutic approaches to enhance neovascularization have emerged. Of these diverse emerging methods, use of growth factors and cells are the two major ones. This review will provide an update on the present understanding of the basic mechanisms of angiogenesis, vasculogenesis, and arteriogenesis, as a basis for designing future pro-neovascularization treatments. Several angiogenic factors including vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) have been implicated in augmenting the neovascularization process. However, single growth factors are not sufficient to generate functional vessels. In synergistic or complementary manner, these factors may be used in harmony to form long-term functional vessels. Cell therapy has the potential to supply stem/progenitor cells and multiple angiogenic factors to the region of ischemia. However, the efficacy of stem cells transplantation may be impaired by low survival rate, insufficient cell number and impaired function in aging and diseases. Combination of cells or cells primed with growth factor(s) or genetic modification may augment the therapeutic efficacy. This paper reviews critical literature in depth to elucidate the mechanism of therapeutic neovascularization, angiogenic factor therapy and cell transplantation. Based on past experience and actual knowledge, we propose future strategies for clinical application and discuss the problems and controversies that need to be addressed in order to fully exploit the potential of growth factors and/or cell transplantation with clinical relevance.

G-CSF-mobilized peripheral blood mononuclear cells from diabetic patients augment neovascularization in ischemic limbs but with impaired capability.

BACKGROUND: Autologous transplantation of mobilized peripheral blood mononuclear cells (M-PBMNCs) is a novel approach to improve critical limb ischemia (CLI) in diabetes. However, endothelial progenitor cells (EPCs) from diabetes are dysfunctional and impaired in ischemia-induced neovascularization. OBJECTIVE: This study aimed to confirm the compromised efficiency of diabetic M-PBMNCs in therapeutic neovascularization, and to determine the underlying mechanisms of this impairment. METHODS: Diabetic M-PBMNCs from 17 diabetic patients or healthy controls, or phosphate-buffered saline (PBS) were injected into the ischemic limbs of streptozotocin-induced diabetic nude mice. The limb blood perfusion, ambulatory score, ischemia damage, capillary/fiber ratio, arteriole density, collateral vessel formation, and pericytes recruitment were evaluated between these three groups. Non-invasive real time image and histopathology were used to detect the in vivo role of transplanted M-PBMNCs. Proliferation and adhesion of EPCs were assayed. In vitro vascular network incorporation and matrigel plug assay were used to test the pro-neovascularization role of M-PBMNCs. RESULTS: Transplantation of diabetic M-PBMNCs also improved neovascularization, but to a lesser extent from that observed with non-diabetic ones. This was associated with the impairment of diabetic M-PBMNCs capacity to differentiate into EPCs, to incorporate into vessel-like tubules in vitro, to participate in vascular-like structure formation in a subcutaneous matrigel plug, and to stimulate the recruitment of pericytes/smooth muscle cells. In addition, there was impairment in vasculogenesis, which was related to the reduced adhesion ability of EPCs from diabetic M-PBMNCs. CONCLUSIONS: Diabetes reduced the capacity of M-PBMNCs to augment neovascularization in ischemia.

Matrix metalloproteinases in bone marrow: roles of gelatinases in physiological hematopoiesis and hematopoietic malignancies.

Turnover balance of extracellular matrix (ECM) is a prerequisite for the structural and functional homeostasis of bone marrow (BM) microenvironment. The role of ECM in physiologic hematopoiesis and its pathologic change in hematopoietic malignancies are very important and under extensive investigation. Accumulating evidence suggests that matrix metalloproteinases (MMPs), a family of zinc-dependent proteinases, take an active part in the physiological and pathological hematopoiesis through remodeling the ECM in BM hematopoietic microenvironment. In this review, we will focus on the roles of MMPs in physiological hematopoiesis, hematopoietic stem cells mobilization/transplantation, and hematological malignancies. Furthermore, the preclinical studies on the role of synthetic MMP inhibitors in the treatment of hematological malignancies will be discussed.

The transcription factor E2F: a crucial switch in the control of homeostasis and tumorigenesis.

The transcription factor E2F plays a crucial role in governing cell proliferation through manipulation of the expression of many genes required for cell cycle progression. As studies are exploring in depth, E2F has grown into a multimember family and has been required for the regulation of a large number of genes involved in various cellular processes. The expanding E2F membership and biological function provide us some new insights relating to the evolution of E2F. One of them is to understand the exact mechanisms by which E2F executes in these different cellular processes during ontogenesis. This review summarizes recent advances in this field, with an emphasis on a notion that E2F acts as a molecular switch in the control of both normal cell and tumor development.

Inhibition of human leukemia xenograft in nude mice by adenovirus-mediated tissue inhibitor of metalloproteinase-3.

Considerable studies have demonstrated the pivotal roles of matrix metalloproteinases (MMPs) in leukemia dissemination and extramedullary infiltration. Tissue inhibitors of matrix metalloproteinases (TIMPs) are multifunctional proteins with MMPs inhibitory effects. However, little is known about the application of TIMPs in the treatment of leukemia. Here, we investigated the effects of TIMP-3 overexpression via adenoviral gene delivery on the in vitro growth and invasiveness of leukemic cells and the in vivo progress of K562-derived xenografts in nude mice. The in vitro invasiveness of K562 cells was markedly impaired by AdTIMP-3 infection. Moreover, TIMP-3 significantly inhibited K562-derived angiogenic factors-induced proliferation, migration and bFGF-induced tube formation of endothelial cells (ECs) in vitro, and reduced VEGF-induced gelatinases expression and activation in ECs. Although TIMP-3 overexpression had no direct effect on the growth of K562 cells in vitro, repeated intratumoral injection of AdTIMP-3 significantly inhibited the growth of K562 xenografts in nude mice. Furthermore, lower microvessel density, less vessel maturity and increased apoptosis were observed in AdTIMP-3-treated K562 xenografts, suggesting the importance of antiangiogenic action of TIMP-3. These data demonstrated the potential of applying AdTIMP-3 as an effective antiangiogenic adjuvant in the treatment of leukemia progression.

Enhanced growth suppression of Philadephia1 leukemia cells by targeting bcr3/abl2 and VEGF through antisense strategy.

An antisense strategy by targeting both bcr3/abl2 and VEGF was designed to suppress the growth of Philadephia1 leukemia cells in vitro and in vivo in mice. In vitro, although bcr3/abl2 or VEGF antisense oligodeoxyribonucleotides (AS-ODNs) alone was able to inhibit the proliferation of K562 cells, the combination of bcr3/abl2 and VEGF AS-ODNs produced an additive inhibitory effect on the growth of K562 cells and significantly enhanced the sensibility of K562 cells to apoptosis-inducing stimuli including STI571. In vivo, the nude mice xenografted with K562 cells received intratumoral injections of bcr3/abl2 and VEGF AS-ODNs showed a significant reduction in leukemia tumor size and microvessel density and an increase of apoptosis in the tumors when compared to the mice that received an individual agent. These results demonstrate that targeting both bcr3/abl2 and VEGF can result in an additive tumor-suppressive action and may represent an excellent strategy to augment the efficacy of chemotherapy in CML.

Akt signaling and its role in postnatal neovascularization.

Postnatal neovascularization has been known to be involved in not only angiogenesis but also vasculogenesis. Several lines of evidence suggest a link between neovascularization and Akt, a family member of serine/threonine protein kinases. Akt phosphorylates endothelial NO synthase (eNOS) and thereby enhances endothelial NO synthesis and influences postnatal vessel growth. Akt signaling is activated by a variety of stimuli in endothelial cells and endothelial progenitor cells (EPCs). Activation of the Akt kinase orchestrates a number of signaling pathways potentially involved in angiogenesis. Dominant negative Akt overexpression leads to functional blocking of EPC bioactivity. Because neovascularization is implicated in the pathophysiology of a number of diseases and is becoming an important therapeutic strategy for those diseases, further dissection of the Akt pathway and elucidation of the downstream effector molecules will lead to a better understanding of postnatal neovascularization and may provide avenues for the development of novel therapeutic interventions. In this review, molecular mechanisms of Akt signal pathway will be discussed with special emphasis on its role in neovascularization.

Stem cell factor improves SCID-repopulating activity of human umbilical cord blood-derived hematopoietic stem/progenitor cells in xenotransplanted NOD/SCID mouse model.

Poor in vivo homing capacity of hematopoietic stem/progenitor cells (HS/PCs) from umbilical cord blood (UCB) can be reversed by short-term ex vivo manipulation with recombinant human stem cell factor (rHuSCF). This study was designed to evaluate the effect of ex vivo manipulation of UCB-derived HS/PCs with rHuSCF on human cell engraftment rates in xenotransplanted NOD/SCID mouse model. The human cell engraftment rates in xenotransplanted primary and secondary NOD/SCID mice were characterized using four-color flow cytometric analysis and progenitor assay. Grafts of rHuSCF-treated UCB CD34(+) cells resulted in significantly higher levels of human cell engraftment than that of nontreated ones in both xenotransplanted primary and secondary NOD/SCID recipients. Fresh UCB CD34(+) cells did not express either of the matrix metalloproteinase (MMP) family members MMP-2 or MMP-9. rHuSCF-treated UCB CD34(+) cells expressed significant levels of MMP-2 and MMP-9. Pretreatment of UCB CD34(+) cells with the specific MMP inhibitor completely blocked human cell engraftment in xenotransplanted NOD/SCID recipients. Our results indicate that ex vivo manipulation of human HS/PCs with rHuSCF might provide an optimal approach to develop more effective stem cell-based therapies in situations where engraftment is delayed due to limiting HS/PCs number, for example, UCB transplantation.

Phosphatidylinositide 3-kinase/AKT in radiation responses.

Ionizing or ultraviolet radiation-induced cellular survival signaling pathways induce development of cancer and insensitivity of tumor cells to radiation therapy. Accumulating evidence suggests that the phosphatidylinositide 3-kinase (PI3K)/AKT signal pathway is a major contributor to radioresistance. In many cell types PI3K/AKT signaling is a key cytoprotective response downstream of the EGFR family receptors and mediated carcinogenesis. Cytokines, such as HGF, IGF-I, and IL-6 also protects cells against apoptosis induced by radiation through PI3K/AKT pathway. The mechanics by which PI3K/AKT signaling functions in radiation responses may include its regulation of mitochondrial proteins, transcription factors, translation machinery, and cell-cycle progression. In addition, cross-talk between the PI3K/AKT pathway and mitogen-activated protein kinases, protein kinase A, and protein kinase C signal pathway may also play an important role.

Signalling mechanisms of anoikis.

Apoptosis following loss of cell anchorage ('anoikis') is of relevance for development, tissue homeostasis and disease. Integrins regulate cell viability through their interaction with the extracellular matrix and they can sense mechanical forces arising from the matrix and convert these stimuli to chemical signals capable of modulating intracellular signal transduction. Recently it has been shown that protein kinase signalling pathways and apoptosis-related molecular control anoikis both positively and negatively. Focal adhesion kinase, when activated by integrins, can suppress anoikis. Phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase may mediate the anoikis-suppressing effects of cells. Conversely, the stress-activated protein kinase/Jun amino-terminal kinase pathway promotes anoikis. In addition, certain bcl-2 and bcl-2-related proteins may also participate in the regulating of anoikis. In this review, molecular mechanisms of signal pathway inducing and perpetuating detachment-induced apoptosis will be discussed with special emphasis on the role of integrins, focal adhesion kinase, phosphatidylinositol 3-kinase/Akt, mitogen-activated protein kinase and bcl-2 family members.

[Down regulatory effects of platelet factor four (PF4) on total adherence and respiratory burst of human neutrophil].

OBJECTIVE: The effect of platelet factor four (PF4) on human neutrophil function was studied. METHODS: Crystal violet dye staining, immunofluorescence labeling, PKC kit assay, NBT and HVA fluoro-spectrophotometry were applied to study the effect of PF4 on total adherence, integrin CD11b level, PKC level and respiratory burst level of resting human neutrophils and FMLP/or PMA-stimulated human neutrophils. RESULTS: It was found that PF4 slightly increased the total adherence of resting human neutrophils. There was no change on integrin CD11b level and respiratory burst level of resting human neutrophils after interaction with PF4. However, PF4 significantly down-regulated the total adherence, integrin CD11b level and respiratory burst level of human neutrophils stimulated by FMLP/or PMA. In addition, PF4 did not influence PKC level on resting and activated human neutrophil. CONCLUSION: These results indicate that PF4 plays a down regulation of the function of human neutrophils. Differing from other members of classical CXC-chemokine family, the signaling of PF4 is not through PLC-PKC signal pathway.

Dual structural requirements for multilineage hematopoietic-suppressive activity of chemokine-derived peptides.

Many chemokines have direct suppressive activity in vitro and in vivo on primitive hematopoietic cells. However, few chemokine-derived peptides have shown a significant activity in inhibiting hematopoiesis. Interestingly, a peptide derived from the 34-58 sequence of the CXC chemokine platelet factor 4 (PF4) produced a 30-40% inhibition of proliferation of murine hematopoietic progenitors (CFU-MK, CFU-GM, and BFU-E) in vitro, at concentrations of 30-60-fold lower than PF4. The aim of the present work was to define the structural parameters and motifs involved in conferring biological activity to the peptide PF4(34-58). Both structural predictions and determinations revealed a new helical motif that was further localized between residues 38 and 46. This helix was necessary for binding of the peptide and for permitting the functional DLQ motif at position 54-56 to activate the putative receptor site. Peptides lacking either the helical or the DLQ motif were devoid of inhibitory activity on the hematopoietic progenitors in vitro. However, among inactive peptides, only those having the helical motif counteracted the inhibition induced by the active peptide PF4(34-58). This suggested that the helix might be required for peptide interactions with a putative receptor site, whereas the DLQ motif would be implicated in the activation of this receptor. These results identify for the first time the dual requirements for the design of chemokine-derived peptides with high suppressive activity on hematopoiesis, as well as for the design of molecules with antagonistic action.

Ex vivo expansion of megakaryocytic cells.

The use of platelet transfusion to ensure the recovery of thrombopoiesis in patients constitutes high-cost support. The identification and cloning of recombinant human thrombopoietin (TPO) and the development of efficient methods of purification of hematopoietic stem cells and progenitor cells have ameliorated the development of strategies of ex vivo expansion of megakaryocyte (MK) progenitor cells and mature MKs. Synergistic combinations of cytokines including TPO, interleukin (IL)-1, IL-3, IL-11, stem cell factor, and FLT-3 ligand induce the ex vivo expansion of colony-forming unit-MK progenitors and MKs from cytokine-mobilized peripheral blood cells, bone marrow, and cord blood CD34+ cells. Depending on the various culture conditions, i.e., combinations of growth factors, initial concentration of CD34+, serum or serum-free cultures, and/or oxygen tensions, the expansion-fold of MKs and their progenitor cells vary greatly. The clinical applications of the reinfusion of ex vivo-generated MK cells have been investigated successfully in cancer patients following high-dose chemotherapy. This review reports the latest information concerning ex vivo expansion of MKs and the current status of clinical trials.