OBJECTIVETo screen human stem cell factor (hSCF) mimetic peptides in vitro with a phage-display random peptide library.

METHODSPhage clones with high hSCF receptor (rc-kit/Ig 1-3)-binding activity was screened from phage-displayed random hepta/dodecapeptide library by phage enzyme-linked immunosorbent assay (ELISA). Phage single DNA was extracted and sequenced. Four kinds of peptide with higher c-Kit/Ig 1-3 binding activity were chosen for synthesis and characterized by using cell proliferation assay with 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) method in UT-7 cells.

RESULTSEleven Ph.D.-C7C clones and eight Ph.D-12 phage clones with high hSCF receptor-binding activity were selected from phage-displayed random hepta/dodecapeptide library, respectively. Sequence analysis showed there were no homologous sequence between hSCF and these screened mimetic peptides except one homologous sequence DPSPHTH found in heptapeptide library. All these four synthesized peptides (CE3, CE16, LE4, and LE20), particularly CE16 and LE20, stimulated UT-7 cell proliferation.

CONCLUSIONFour hSCF mimetic peptides were successfully isolated from phage-displayed random peptide library..

Humans ; Peptide Library ; Peptides ; genetics ; isolation & purification ; Stem Cell Factor ; genetics ; isolation & purification

In order to investigate the levels of stem cell factor (SCF) and its receptor c-kit protein and mRNA in pediatric aplastic anemia (AA) and their relevance to the pathogenesis, immunocytochemical and in situ hybridization were utilized to detect the expression of SCF and its receptor c-kit gene protein and mRNA, respectively in 59 children with AA and 51 normal controls. The relationship between SCF and c-kit and the pathogenesis of AA was analyzed subsequently. The results showed that the positive rate of SCF protein and mRNA expression in children with AA was significantly lower than that in healthy controls (P < 0.05). However, there was no significant difference in the positive rate of c-kit protein and mRNA expression between children with AA and control group (P > 0.05). It was concluded that the expression of SCF is significantly decreased in children with AA, which may be closely associated with the pathogenesis of the AA. c-kit may be unrelated to the development of pediatric AA. Therefore, AA in children may have abnormalities at SCF/c-kit signal transduction levels.
Anemia, Aplastic/etiology ; Anemia, Aplastic/*metabolism ; RNA, Messenger/biosynthesis ; RNA, Messenger/genetics ; Receptors, Colony-Stimulating Factor/*biosynthesis ; Receptors, Colony-Stimulating Factor/genetics ; Stem Cell Factor/*biosynthesis ; Stem Cell Factor/genetics

Stem cell growth factor (SCGF) is an early-acting hematopoitic cytokine that has two isoforms including hSCGF with full length molecules and hSCGFbeta, 78 amino acids of which lost in the conserved calcium-dependent carbohydrate-recognition domain (CRD). It has been demonstrated that hSCGFbeta is strictly species-specific in regulating he-matopoiesis. This study was aimed to explore whether human SCGF can exert synergistic stimulatory effect on heterogenous murine CFU-GM progenitor. Firstly, hSCGF cDNA was amplified from human fetal liver cDNA library by using two-step PCR. The hSCGF mature peptide coding sequence was subsequently placed at downstream of glutathione S-transferase (GST) sequence in GST gene fusion expression vector. The results indicated that there existed an additional 60 kD protein compared with mock BL21 when the cells hosting recombinant plasmid were induced with IPTG at 37 degrees C. SDS-PAGE analysis demonstrated that the GST-hSCGF fusion protein mainly existed in insoluble form. When induced at low temperature (28 degrees C), the recombinant protein was mostly soluble. The GST-fusion recombinant protein was subsequently purified by using affinity chromatography. The clonogenic assay revealed that, unlike hSCGFbeta, hSCGF had the granulocyte/macrophage promoting activity (GPA) for murine bone marrow GM progenitor. It is concluded that, in contrast to human SCGFbeta, the intact molecular hSCGF may have no species specificity, implying that CRD domain in human SCGFbeta does not directly bind to corresponding SCGF receptor, but may have certain biological function.
Cloning, Molecular ; DNA, Complementary ; biosynthesis ; genetics ; isolation & purification ; Hematopoiesis ; genetics ; Humans ; Species Specificity ; Stem Cell Factor ; biosynthesis ; genetics ; isolation & purification

OBJECTIVETo study the mechanism of stem cell factor (SCF) in bone marrow stem cells heart transplantation (BMT) and the influence of bone marrow mobilization on the transplantation efficacy.

METHODSRats with acute myocardial infarction (AMI) accepted BMT. The SCF expression in the bone marrow was measured by RT-PCR after the operation. Then bone marrow stem cells with different SCF levels for the transplantation were used and the cardiac function was compared by using echocardiography. The SCF protein expression in the heart, plasma and bone marrow was detected by ELISA.

RESULTSSCF expression level decreased significantly 1 week after AMI (P < 0.01), but it didn't decrease in those accepting BMT. Though the rats accepted BMT with bone marrow stem cells from different sources, the cardiac function showed no difference (P > 0.05). After BMT, the SCF protein level in the plasma decreased significantly (P < 0.05).

CONCLUSIONSBMT may make mobilization through SCF. Bone marrow stem cells from rats with AMI and also those with myocardial infarction plus BMT therapy can also be used for the transplantation into heart, and have no influence on cardiac function improvement.

Animals ; Bone Marrow Cells ; cytology ; Bone Marrow Transplantation ; Male ; Mesenchymal Stem Cell Transplantation ; Myocardial Infarction ; therapy ; RNA, Messenger ; genetics ; Rats ; Rats, Inbred Lew ; Stem Cell Factor ; genetics ; metabolism

OBJECTIVETo investigate the expression of bFGF, ET-1 and SCF in different passages of cultured dermal papilla cells (DPC), and their possible effect on biological behaviour of DPC.

METHODSThe expression of bFGF, ET-1 and SCF in different passages of cultured DPC was detected by immunocytochemistry and in situ hybridization.

RESULTThe expression of ET-1 and SCF in early passages of cultured DPC was stronger, but became negative in late passages (>6 passages). The stronger the expression of ET-1 and SCF in DPC, the higher ability of DPC to induce hair follicle regeneration.

CONCLUSIONThe expression strength of ET-1 and SCF is related to the ability of DPC inducing hair follicle regeneration.

Endothelin-1 ; analysis ; genetics ; Fibroblast Growth Factor 2 ; analysis ; genetics ; Hair Follicle ; chemistry ; cytology ; physiology ; Humans ; Immunohistochemistry ; In Situ Hybridization ; Stem Cell Factor ; analysis ; genetics

Mesenchymal stem cells (MSC) are multipotent in nature and believed to facilitate the engraftment of hematopoietic stem cells (HSC) when transplanted simultaneously in animal studies and even in human trials. In this study, we transfected culture-expanded MSC with granulocyte macrophage-colony stimulating factor (GMCSF) and stem cell factor (SCF) cytokine genes and then cotransplanted with mononuclear cells (MNC) to further promote HSC engraftment. MNC were harvested from cord blood and seeded in long-term culture for ex vivo MSC expansion. A total of 1 x 10(7) MNC plus MSC/microliter were introduced to the tail vein of nonobese diabetic/severe combined immunodeficiency mice. After 6-8 weeks later, homing and engraftment of human cells were determined by flow cytometry and fluorescence in situ hybridization studies. The total nucleated cell count and the engraftment of CD45+/CD34+ cells and XX or XY positive human cells were significantly increased in cotransplanted mice and even higher with the cytokine gene-transfected MSC (GM-CSF>SCF, p<0.05) than in transplantation of MNC alone. These results suggest that MSC transfected with hematopoietic growth factor genes are capable of enhancing the hematopoietic engraftment. Delivering genes involved in homing and cell adhesions, CXCR4 or VLA, would further increase the efficiency of stem cell transplantation in the future.
Transfection/*methods ; Stem Cell Factor/genetics/*metabolism ; Mice, SCID ; Mice ; Mesenchymal Stem Cells/*metabolism ; Mesenchymal Stem Cell Transplantation/*methods ; Hematopoietic Stem Cell Transplantation/*methods ; Granulocyte Macrophage Colony-Stimulating Factors, Recombinant/*metabolism ; Graft Survival/*immunology ; Genetic Enhancement/methods ; Animals

Irreversible destruction of bronchi and alveoli can lead to multiple incurable lung diseases. Identifying lung stem/progenitor cells with regenerative capacity and utilizing them to reconstruct functional tissue is one of the biggest hopes to reverse the damage and cure such diseases. Here we showed that a rare population of SOX9 basal cells (BCs) located at airway epithelium rugae can regenerate adult human lung. Human SOX9 BCs can be readily isolated by bronchoscopic brushing and indefinitely expanded in feeder-free condition. Expanded human SOX9 BCs can give rise to alveolar and bronchiolar epithelium after being transplanted into injured mouse lung, with air-blood exchange system reconstructed and recipient's lung function improved. Manipulation of lung microenvironment with Pirfenidone to suppress TGF-β signaling could further boost the transplantation efficiency. Moreover, we conducted the first autologous SOX9 BCs transplantation clinical trial in two bronchiectasis patients. Lung tissue repair and pulmonary function enhancement was observed in patients 3-12 months after cell transplantation. Altogether our current work indicated that functional adult human lung structure can be reconstituted by orthotopic transplantation of tissue-specific stem/progenitor cells, which could be translated into a mature regenerative therapeutic strategy in near future.
Bronchiectasis ; genetics ; metabolism ; Humans ; Pulmonary Alveoli ; cytology ; metabolism ; SOX9 Transcription Factor ; genetics ; metabolism ; Stem Cell Transplantation ; methods ; Stem Cells ; cytology ; metabolism

OBJECTIVETo evaluate the therapeutic effect of transplantation of mesencephalic neural stem cells (mNSCs) genetically modified by glial cell line-derived neurotrophic factor (GDNF) gene in a rat model of Parkinson disease.

METHODSmNSCs isolated from the lateral component of the midbrain of fetal rats at gestational age of 14 or 15 days were cultured for 5 days before genetic modification with GFP or GDNF gene. Rat models of Parkinson disease established by stereotactic injection of 6-hydroxy dopamine in the ventral area of the midbrain and the medial forebrain bundle were randomized into 3 groups to receive PBS injection, GFP gene-modified mNSCs transplantation, or GDNF gene-modified mNSCs transplantation into the right stratum. The behavioral changes of the rats were evaluated by observing rotations induced by intraperitoneal injection of apomorphine after the transplantation, and the survival, migration and differentiation of the transplanted cells were identified by immunohistochemistry.

RESULTSTransplantation with GDNF gene-modified mNSCs significantly improved the behavioral abnormalities of the rat models as compared with PBS injection and GFP gene-modified mNSCs transplantation. At 56 days after the transplantation, a greater number of the transplanted cells survived in the rat brain and more differentiated dopaminergic neurons were detected in GDNF gene-modified mNSCs transplantation group than in GFP gene-modified mNSCs transplantation group.

CONCLUSIONGDNF gene-modified mNSCs transplantation can significantly improve dyskinesia in rat models of Parkinson disease, but the molecular mechanism needs further clarification.

Animals ; Disease Models, Animal ; Glial Cell Line-Derived Neurotrophic Factor ; genetics ; therapeutic use ; Mesencephalon ; cytology ; Neural Stem Cells ; transplantation ; Parkinson Disease ; therapy ; Rats ; Stem Cell Transplantation

We studied the function and mechanism of miR-24 in regulating beta-like globin gene expression. We first detected the expression of miR-24 during erythroid differentiation and also detected the globin gene expression in miR-24 overexpressing K562 cells through q-PCR. Dual-luciferase reporter assay and Western blotting were used to identify target genes of miR-24. "Rescue experiment" was further used to investigate the regulation of miR-24 on globin gene expression whether depending on targeting Sp1 or not. We found that miR-24 increased during hemin-induced K562 cells and EPO-induced HPCs (hematopoietic progenitor cells) erythroid differentiation. Overexpression of miR-24 in K562 cells promoted the epsilon- and gamma-globin gene expression during hemin-induced erythroid differentiation through targeting the negative globin regulator Sp1. These results suggested that miR-24 can improve the expression of beta-like globin gene through targeting Sp1.
Cell Differentiation ; Gene Expression Regulation ; Hematopoietic Stem Cells ; metabolism ; Humans ; K562 Cells ; MicroRNAs ; genetics ; Sp1 Transcription Factor ; genetics ; epsilon-Globins ; genetics ; gamma-Globins ; genetics

We transfected human neural stem cells using lentiviral vectors encoding glial cell line derived neurotrophic factor (GDNF) to study its expression level in vitro and to get a stable cell line expressing GDNF. First, GDNF gene was sub-cloned into the lentiviral transfer vectors. Then, the recombinant lentiviral supernatants were packaged by 293T cells through three plasmids transient co-transfection method using standard lipofectamine reagent. The viral titers were tested by the transfection efficiency of 293T cells. At the same time, human neural stem cells (hNSC) were transfected under different multiplicity of infection. GDNF gene expression level and protein secretion level of hNSC were tested by real-time PCR and ELISA methods after transfection. Lentiviral vectors encoding GDNF were constructed. Using lentiviral vectors encoding GDNF we successfully transfected human neural stem cells, and got a stable neural stem cell lines over-expressing GDNF. Furthermore, the results indicated that GDNF expression was influenced by the multiplicity of infection. Human neural stem cells could over-express GDNF through lentivial vectors tranfection. Its gene expression level and protein expression level correlate with the multiplicity of infection.
Embryonic Stem Cells ; metabolism ; Genetic Vectors ; genetics ; Glial Cell Line-Derived Neurotrophic Factor ; biosynthesis ; genetics ; Humans ; Lentivirus ; genetics ; Nerve Tissue ; cytology ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection