[Show abstract][Hide abstract] ABSTRACT: Erythrocytes and megakaryocytes (MK) are derived from a common progenitor that undergoes lineage specification. Lysophosphatidic acid (LPA), a lipid growth factor was previously shown to be a regulator for erythropoietic process through activating LPA receptor 3 (LPA3). However, whether LPA affects megakaryopoiesis remains unclear. In this study, we used K562 leukemia cell line as a model to investigate the roles of LPA in MK differentiation. We demonstrated that K562 cells express both LPA2 and LPA3, and the expression levels of LPA2 are higher than LPA3. Treatment with phorbol 12-myristate 13-acetate, a commonly used inducer of megakaryopoiesis, reciprocally regulates the expressions of LPA2 and LPA3. By pharmacological blockers and knockdown experiments, we showed that activation of LPA2 suppresses whereas, LPA3 promotes megakaryocytic differentiation in K562. The LPA2-mediated inhibition is dependent on β-catenin translocation, whereas reactive oxygen species (ROS) generation is a downstream signal for activation of LPA3. Furthermore, the hematopoietic transcriptional factors GATA-1 and FLI-1, appear to be involved in these regulatory mechanisms. Taken together, our results suggested that LPA2 and LPA3 may function as a molecular switch and play opposing roles during megakaryopoiesis of K562 cells.
Full-text · Article · Nov 2014 · Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids
[Show abstract][Hide abstract] ABSTRACT: Currently, many gastrointestinal diseases are a major reason for the increased mortality rate of children and adults every year. Additionally, these patients may cope with the high cost of the parenteral nutrition (PN), which aids in the long-term survival of the patients. Other treatment options include surgical lengthening, which is not sufficient in many cases, and intestinal transplantation. However, intestinal transplantation is still accompanied by many challenges, including immune rejection and donor availability, which may limit the transplant's success. The development of more safe and promising alternative treatments for intestinal diseases is still ongoing. Stem cell-based therapy (SCT) and tissue engineering (TE) appear to be the next promising choices for the regeneration of the damaged intestine. However, suitable stem cell source is required for the SCT and TE process. Thus, in this review we discuss how intestinal stem cells (ISCs) are a promising cell source for small intestine diseases. We will also discuss the different markers were used to identify ISCs. Moreover, we discuss the dominant Wnt signaling pathway in the ISC niche and its involvement in some intestinal diseases. Additionally, we discuss ISC culture and expansion, which are critical to providing enough cells for SCT and TE. Finally, we conclude and recommend that ISC isolation, culture and expansion should be considered when SCT is a treatment option for intestinal disorders. Therefore, we believe that ISCs should be considered a cell source for SCT for many gastrointestinal diseases and should be highlighted in future clinical applications.
[Show abstract][Hide abstract] ABSTRACT: Skin injuries, congenital lesions, melasma, Addison's disease and many pigment abnormalities prompt us to search for an effective whitening agent. Ideal whitening agent is a natural compound that can inhibit melanogenesis and has no cytotoxic effects. In a previous study, we have developed an optimum method for the production and characterization of ectoine from a halophilic bacterium isolated from a salt environment in Taiwan was identified as Marinococcus sp. In the present study, we screened the whitening properties of the biosynthesized ectoine using mouse and human melanoma cell lines, B16-F0 and A2058. Here, we examined the cell viabilities of melanoma cells after ectoine treatment at various concentrations up to 500 μM. Also, we addressed the melanin synthesis of melanoma cells after treatment with ectoine. The inhibitory effects of ectoine on tyrosinase activity were assessed in both mushroom tyrosinase and cellular tyrosinase. Furthermore, we investigated the type of inhibition of mushroom tyrosinase using Lineweaver–Burk enzyme kinetic. The melanogenesis-related gene expression (tyrosinase, TRP1, TRP2 and MITF) and their protein secretion were determined by the assays of quantitative real-time PCR and western blots, respectively. Our results demonstrated that ectoine is a safe and effective whitening agent, inhibited melanin synthesis, reduced both mushroom tyrosinase and cellular tyrosinase, and had various inhibitory effects on the expressions of melanogenesis-related genes and secretion of proteins in mouse and human melanoma cell lines. Thus, we suggest that ectoine can serve as a useful and safe new agent in cosmetic and clinical applications.
[Show abstract][Hide abstract] ABSTRACT: Serratia marcescens C3 produces a natural red-pigment, prodigiosin, which exhibits immunosuppressive properties, in vitro apoptotic effects, and in vivo anti-tumor activities. This work seeks to improve the production of prodigiosin by S. marcescens C3 using various strategies. Starch and peptone were identified as the optimized carbon and nitrogen sources for the production of prodigiosin, yielding a prodigiosin concentration of 2.3 g/L. This value was significantly increased to 6.7 g/L using a carbon/nitrogen ratio of 6/4 (starch/peptone = 16 g/L/10.67 g/L). To enhance prodigiosin production even further, a statistical experimental design methodology was utilized to optimize the composition of the culture medium that is utilized in the production of prodigiosin. Prodigiosin production of 7.07 g/L was achieved when the concentrations of two trace compounds, FeSO4·4H2O and MnSO4·4H2O, were optimized using the statistical experimental design methodology. Their optimal concentrations were 0.56 mM and 3.25 mM, respectively. Ultimately, the production of prodigiosin was increased from 2.3 g/L to 15.6 g/L, or by a factor of nearly seven by immobilizing microorganisms in 3% calcium alginate beads.
[Show abstract][Hide abstract] ABSTRACT: Background aims:
The number of hematopoietic stem cells (HSCs) is critical for transplantation. The ex vivo expansion of mobilized peripheral blood (MPB) HSCs is of clinical value for reconstitution to meet clinical need.
This study proposed a simple, defined, stromal-free and serum-free culture system (SF-HSC medium) for clinical use, which is composed of Iscove's modified Dulbecco's medium, cytokine cocktails and serum substitutes. This study also characterized the cellular properties of expanded MPB CD133(+) HSCs from patients with hematologic malignancies and healthy donors by surface antigen, colony-forming cell, long-term culture-initiating cell, gene expression and in vivo engraftment assays.
The expanded fold values of CD45(+) white blood cells and CD34(+), CD133(+), CD34(+)CD38(-), CD133(+)CD38(-), CD34(+)CD133(+), colony-forming and long-term culture-initiating cells at the end of 7-day culture from CD133(+) MPB of hematologic malignancies were 9.4-fold, 5.9-fold, 4.0-fold, 35.8-fold, 21.9-fold, 3.8-fold, 11.8-fold and 6.7-fold, and values from healthy donor CD133(+) MPB were 20.7-fold, 14.5-fold, 8.5-fold, 83.8-fold, 37.3-fold, 6.2-fold, 19.1-fold and 14.6-fold. The high enrichment of CD38(-) cells, which were either CD34(+) or CD133(+), sustained the proliferation of early uncommitted HSCs. The expanded cells showed high levels of messenger RNA expression of HOBX4, ABCG2 and HTERT and had the in vivo ability to re-populate NOD/SCID mice.
Our results demonstrated that an initial, limited number of MPB CD133(+) HSCs could be expanded functionally in SF-HSC medium. We believe that this serum-free expansion technique can be employed in both basic research and clinical transplantation.
[Show abstract][Hide abstract] ABSTRACT: Protein arginine methylation is emerging as a pivotal posttranslational modification involved in regulating various cellular processes; however, its role in erythropoiesis is still elusive. Erythropoiesis generates circulating red blood cells which are vital for body activity. Deficiency in erythroid differentiation causes anemia which compromises the quality of life. Despite extensive studies, the molecular events regulating erythropoiesis are not fully understood. This study showed that the increase in protein arginine methyltransferase 1 (PRMT1) levels, via transfection or protein transduction, significantly promoted erythroid differentiation in the bipotent human K562 cell line as well as in human primary hematopoietic progenitor CD34+ cells. PRMT1 expression enhanced the production of hemoglobin and the erythroid surface marker glycophorin A, and also up-regulated several key transcription factors, GATA1, NF-E2 and EKLF, which are critical for lineage-specific differentiation. The shRNA-mediated knockdown of PRMT1 suppressed erythroid differentiation. The methyltransferase activity-deficient PRMT1G80R mutant failed to stimulate differentiation, indicating the requirement of arginine methylation of target proteins. Our results further showed that a specific isoform of p38 MAPK, p38α, promoted erythroid differentiation, whereas p38β did not play a role. The stimulation of erythroid differentiation by PRMT1 was diminished in p38α- but not p38β-knockdown cells. PRMT1 appeared to act upstream of p38α, since expression of p38α still promoted erythroid differentiation in PRMT1-knockdown cells, and expression of PRMT1 enhanced the activation of p38 MAPK. Importantly, we showed for the first time that PRMT1 was associated with p38α in cells by co-immunoprecipitation and that PRMT1 directly methylated p38α in in vitro methylation assays. Taken together, our findings unveil a link between PRMT1 and p38α in regulating the erythroid differentiation program and provide evidence suggesting a novel regulatory mechanism for p38α through arginine methylation.
[Show abstract][Hide abstract] ABSTRACT: Mesenchymal stem cells (MSCs) are multi-potent with numerous mesenchymal-lineage differentiation potential and immunomodulatory capabilities. However, the immunoregulatory properties of MSCs are not clearly defined. The objective of the present study was to elucidate the role(s) of MSCs in IL-17 production and the subsequent effect(s) on neutrophil activation. We have demonstrated that human bone marrow-derived MSCs (BM-MSCs) instruct anti-CD3/anti-CD28 antibody-activated CD4(+) CD45RO(+) memory T cells, but not other CD4(+) subsets or CD8(+) T cells, to produce IL-17 after cell-cell contact. After the addition of IL-17, neutrophil phagocytic activity was increased. This is the first report on the ability of BM-MSCs to induce IL-17 production in memory CD4(+) T cells that, in turn, promotes enhanced phagocytic activity of neutrophils. These results suggest that MSCs regulate the functional activation of neutrophils via their role in modulating IL-17 from CD4(+) CD45RO(+) memory T cells.
[Show abstract][Hide abstract] ABSTRACT: Human mesenchymal stromal cells (hMSCs) play a crucial role in tissue engineering and regenerative medicine and thus have important clinical potential for cell-based therapy. However, the limited cell number and the difficulty in detecting these cells in vivo have restricted many hMSC studies. Therefore, the development of hMSCs immortalized with telomerase and expressing red fluorescence protein will facilitate their expansion and detection in vivo, and these cells will be important for both to stem cell research and clinical use. In this chapter, we describe the protocols used to establish telomerase- and red fluorescence protein-expressing immortalized hMSCs using a nonviral transfection method. These cells will be useful tools for stem cell research and translational studies.
No preview · Article · Jan 2012 · Methods in molecular biology (Clifton, N.J.)
[Show abstract][Hide abstract] ABSTRACT: Lysophosphatidic acid (LPA), an extracellular lipid mediator, exerts multiple bioactivities through activating G protein-coupled receptors. LPA receptor 3 (LPA(3)) is a member of the endothelial differentiation gene family, which regulates differentiation and development of the circulation system. However, the relationship among the LPA receptors (LPARs) and erythropoiesis is still not clear. In this study, we found that erythroblasts expressed both LPA(1) and LPA(3), and erythropoietic defects were observed in zLPA(3) antisense morpholino oligonucleotide-injected zebrafish embryos. In human model, our results showed that LPA enhanced the erythropoiesis in the cord blood-derived human hematopoietic stem cells (hHSCs) with erythropoietin (EPO) addition in the plasma-free culture. When hHSCs were treated with Ki16425, an antagonist of LPA(1) and LPA(3), erythropoietic process of hHSCs was also blocked, as detected by mRNA and protein expressions of CD71 and GlyA. In the knockdown study, we further demonstrated that specific knockdown of LPA(3), not LPA(1), blocked the erythropoiesis. The translocation of β-catenin into the nucleus, a downstream response of LPAR activation, was blocked by Ki16425 treatment. In addition, upregulation of erythropoiesis by LPA was also blocked by quercetin, an inhibitor of the β-catenin/T-cell factor pathway. Furthermore, the enhancement of LPA on erythropoiesis was diminished by blocking c-Jun-activated kinase/signal transducer and activator of transcription and phosphatidylinositol 3-kinase/AKT activation, the downstream signaling pathways of EPO receptor, suggested that LPA might play a synergistic role with EPO to regulate erythropoietic process. In conclusion, we first reported that LPA participates in EPO-dependent erythropoiesis through activating LPA(3).
[Show abstract][Hide abstract] ABSTRACT: Chondroitin sulfate C (CSC) is a kind of glycosaminoglycans (GAGs) with molecular weights of 10,000 to 50,000 Da and a high charge density. GAGs are major components in extracellular matrix (ECM), which play important role in the regulation of cell proliferation, migration, and differentiation. In this study, we studied the effects of chondroitin sulfate C (CSC) on the differentiation of human mesenchymal stem cells (MSCs) toward the chondrocyte lineage. The MSCs were either cultured on type II collagen (COL II) scaffolds with high molecular weight CSC addition in the medium (free CSC) or with free oligosaccharide CSC. Special attention was given to the effects of MSCs cultured on CSC cross-linked type II scaffolds (cross-linked CSC). According to the analysis of histology stain, gene expression, and ECM secretion, our results showed that MSCs cultured with free CSC, free oligosaccharides CSC, and on the cross-linked CSC scaffolds all would be induced into chondrocytes. Moreover, free oligosaccharide CSC present in the microenvironment could significantly up-regulate MSC chondrogenesis gene expression and stimulate cartilage ECM accumulation more than free CSC with high molecular weight after 3-week induction. Importantly, cross-linked CSC had the most excellent effects on the MSC chondrogenesis. Thus, we believed that cross-linked CSC in the scaffold would play the similar roles with free oligosaccharide CSC in the medium. Cross-linked CSC would be a potential candidate for cartilage repair in the cell therapy and tissue engineering.
No preview · Article · Oct 2010 · Journal of Bioscience and Bioengineering
[Show abstract][Hide abstract] ABSTRACT: The feasibility of using genipin cross-linked type II collagen scaffold with rabbit bone marrow mesenchymal stem cells (RBMSCs) to repair cartilage defect was herein studied. Induction of RBMSCs into chondrocytic phenotype on type II collagen scaffold in vitro was conducted using TGF-β 3 containing medium. After 3-weeks of induction, chondrocytic behavior, including marker genes expression and specific extracellular matrix (ECM) secretion, was observed. In the in vivo evaluation experiment, the scaffolds containing RBMSCs without prior induction were autologous implanted into the articular cartilage defects made by subchondral drilling. The repairing ability was evaluated. After 2 months, chondrocyte-like cells with lacuna structure and corresponding ECM were found in the repaired sites without apparent inflammation. After 24 weeks, we could easily find cartilage structure the same with normal cartilage in the repair site. In conclusion, it was shown that the scaffolds in combination of in vivo conditions can induce RBMSCs into chondrocytes in repaired area and would be a possible method for articular cartilage repair in clinic and cartilage tissue engineering.
[Show abstract][Hide abstract] ABSTRACT: Protein-arginine methyltransferase 1 (PRMT1) plays pivotal roles in various cellular processes. However, its role in megakaryocytic differentiation has yet to be investigated. Human leukemia K562 cells have been used as a model to study hematopoietic differentiation. In this study, we report that ectopic expression of HA-PRMT1 in K562 cells suppressed phorbol 12-myristate 13-acetate (PMA)-induced megakaryocytic differentiation as demonstrated by changes in cytological characteristics, adhesive properties, and CD41 expression, whereas knockdown of PRMT1 by small interference RNA promoted differentiation. Impairment of the methyltransferase activity of PRMT1 diminished the suppressive effect. These results provide evidence for a novel role of PRMT1 in negative regulation of megakaryocytic differentiation. Activation of ERK MAPK has been shown to be essential for megakaryocytic differentiation, although the role of p38 MAPK is still poorly understood. We show that knockdown of p38alpha MAPK or treatment with the p38 inhibitor SB203580 significantly enhanced PMA-induced megakaryocytic differentiation. Further investigation revealed that PRMT1 promotes activation of p38 MAPK without inhibiting activation of ERK MAPK. In p38alpha knockdown cells, PRMT1 could no longer suppress differentiation. In contrast, enforced expression of p38alpha MAPK suppressed PMA-induced megakaryocytic differentiation of parental K562 as well as PRMT1-knockdown cells. We propose modulation of the p38 MAPK pathway by PRMT1 as a novel mechanism regulating megakaryocytic differentiation. This study thus provides a new perspective on the promotion of megakaryopoiesis.
No preview · Article · May 2010 · Journal of Biological Chemistry
[Show abstract][Hide abstract] ABSTRACT: Human mesenchymal stromal cells (hMSC) play a crucial role in tissue engineering and regenerative medicine, and have important clinical potential for cell therapy. However, many hMSC studies have been restricted by limited cell numbers and difficult detection in vivo. To expand the lifespan, hMSC are usually immortalized by virus-mediated gene transfer. However, these genetically modified cells easily lose critical phenotypes and stable genotypes because of insertional mutagenesis.
We used a non-viral transfection method to establish human telomerase reverse transcriptase-immortalized cord blood hMSC (hTERT-cbMSC). We also established red fluorescent protein (RFP)-expressing hTERT-cbMSC (hTERT/RFP-cbMSC) by the same non-viral transfection method, and these cells were injected into a rat model with traumatic brain injury for in vivo detection analysis.
The hTERT-cbMSC could grow more than 200 population doublings with a stable doubling time and maintained differentiation capacities. hTERT/RFP-cbMSC could proliferate efficiently within 2 weeks at the injury location and could be detected easily under a fluorescent microscope. Importantly, both hTERT-cbMSC and hTERT/RFP-cbMSC showed no chromosomal abnormalities by karyotype analysis and no tumor formation in severe combined immunodeficient (SCID) mice by transplantation assay.
We have developed immortalized cbMSC with hTERT expression and RFP expression, which will be useful tools for stem cell research and translational study.
[Show abstract][Hide abstract] ABSTRACT: A complete process for mass generation of megakaryocytes from hematopoietic stem cells under serum-free conditions has great clinical potential for rapid platelet reconstruction in thrombocytopenia patients. We have previously reported on the generation of an optimized serum-free medium (serum-free hematopoietic stem cell medium) for ex vivo expansion of CD34(+) cells. Here, we further generated large amounts of functional megakaryocytes from serum-free expanded CD34(+) cells under a complete and optimal serum-free condition for complying with clinical regulations.
Serum substitutes and cytokines were screened and optimized for their concentration for megakaryocyte generation by systemically methods. Serum-free induced megakaryocytes were characterized by surface antigens, gene expression, ex vivo megakaryocyte activation ability, and ability of megakaryocyte and platelet recovery in nonobese diabetic/severe combined immunodeficient mice.
The optimal serum-free megakaryocyte induction medium was Iscove's modified Dulbecco's medium containing serum substitutes (i.e., human serum albumin, human insulin, and human transferrin) and a cytokine cocktail (i.e., thrombopoietin, stem cell factor, Fms-like tyrosine kinase 3 ligand, interleukin-3, interleukin-6, interleukin-9, and granulocyte-macrophage colony-stimulating factor). After induction, induced megakaryocytes expressed CD41a and CD61 surface antigens, nuclear factor erythroid-derived 2 and GATA-1 transcription factors and megakaryocyte activation ability. Importantly, transplantation of induced megakaryocytes could accelerate megakaryocyte and platelet recovery in irradiated nonobese diabetic/severe combined immunodeficient mice.
In conclusion, we have developed a serum-free megakaryocyte induction medium, and the combination of serum-free megakaryocyte and serum-free hematopoietic stem cell media can generate a large amount of functional megakaryocytes efficiently. Our method represents a promising source of megakaryocytes and platelets for future cell therapy.
No preview · Article · Sep 2009 · Experimental hematology
[Show abstract][Hide abstract] ABSTRACT: Ex vivo generation of megakaryocytes from hematopoietic stem cells (HSCs) is crucial to HSC research and has important clinical potential for thrombocytopenia patients to rapid platelet reconstruction. In this study, factorial design and steepest ascent method were used to screen and optimize the effective cytokines (10.2 ng/ml TPO, 4.3 ng/ml IL-3, 15.0 ng/ml SCF, 5.6 ng/ml IL-6, 2.8 ng/ml FL, 2.8 ng/ml IL-9, and 2.8 ng/ml GM-CSF) in megakaryocyte induction medium that facilitate ex vivo megakaryopoiesis from CD34(+) cells. After induction, the maximum fold expansion for accumulated megakaryocytes was almost 5000-fold, and the induced megakaryocytes were characterized by analysis of gene expression, polyploidy and platelet activation ability. Furthermore, the combination of megakaryocyte induction medium and HSC expansion medium can induce and expand a large amount of functional megakaryocytes efficiently, and might be a promising source of megakaryocytes and platelets for cell therapy in the future.
No preview · Article · Dec 2008 · Biochemical and Biophysical Research Communications
[Show abstract][Hide abstract] ABSTRACT: Scaffolds provide a template for cell distribution, growth, differentiation and extracellular matrix accumulation in a three-dimensional environment. Recent studies have demonstrated the potential of scaffolds for enhancing articular cartilage repair both in vitro and in vivo investigations. Mesenchymal stem cells derived from human umbilical cord blood (CBMSCs) have been characterized by their multipotency to differentiate into mesenchyme-lineage cell types, including chondrocytes, osteoblasts, and adipocytes. In this study, chondrogenesis of CBMSCs was performed in a chemically synthesized thermoreversible gelation polymer (TGP). CBMSCs were embedded in the TGP and supplemented with ascorbic acid and transforming growth factor-beta 3. After a 4-week induction, the results showed that CBMSCs formed into spheroid pellets and increased in size. The induced cells in the TGP expressed specific mRNA of collagen type II, aggrecan, and Sox9 for chondrocytes. Furthermore, CBMSCs embedded in TGP had higher ratio of glycosaminoglycan secretion to DNA content than the traditional induction method by aggregating pellet culture. These results demonstrated that chemically synthesized TGP provided a competent 3-dimentional culture environment for CBMSCs to differentiate into chondrocytes and may be applied clinically to induce chondrogenic differentiation of CBMSCs for cartilage repair in the future.
Full-text · Article · Sep 2008 · The Chinese journal of physiology
[Show abstract][Hide abstract] ABSTRACT: Lysophosphatidic acid (LPA), a low-molecular-weight lysophospholipid enriched in platelets and mildly oxidized low-density lipoproteins, is known to regulate inflammation and atherosclerosis by binding to its cognate receptors. In this study, we reported that LPA upregulated interleukin-1 beta (IL-1 beta) expression in mouse J774A.1 macrophages. By using pharmacological inhibitors, it was suggested that G(i)/Rho activation and subsequent reactive oxygen species (ROS) production were involved in IL-1 beta induction. In addition, IL-1 beta induction by LPA was also observed in human primary macrophages. In summary, LPA is involved in the processes of inflammation by affecting macrophage behavior.
Full-text · Article · Jun 2008 · Journal of Biomedical Science