Small molecules enable highly efficient neuronal conversion of human fibroblasts.

Forced expression of proneural transcription factors has been shown to direct neuronal conversion of fibroblasts. Because neurons are postmitotic, conversion efficiencies are an important parameter for this process. We present a minimalist approach combining two-factor neuronal programming with small molecule-based inhibition of glycogen synthase kinase-3ß and SMAD signaling, which converts postnatal human fibroblasts into functional neuron-like cells with yields up to >200% and neuronal purities up to >80%.

Erythroid differentiation of human induced pluripotent stem cells is independent of donor cell type of origin.

Epigenetic memory in induced pluripotent stem cells, which is related to the somatic cell type of origin of the stem cells, might lead to variations in the differentiation capacities of the pluripotent stem cells. In this context, induced pluripotent stem cells from human CD34(+) hematopoietic stem cells might be more suitable for hematopoietic differentiation than the commonly used fibroblast-derived induced pluripotent stem cells. To investigate the influence of an epigenetic memory on the ex vivo expansion of induced pluripotent stem cells into erythroid cells, we compared induced pluripotent stem cells from human neural stem cells and human cord blood-derived CD34(+) hematopoietic stem cells and evaluated their potential for differentiation into hematopoietic progenitor and mature red blood cells. Although genome-wide DNA methylation profiling at all promoter regions demonstrates that the epigenetic memory of induced pluripotent stem cells is influenced by the somatic cell type of origin of the stem cells, we found a similar hematopoietic induction potential and erythroid differentiation pattern of induced pluripotent stem cells of different somatic cell origin. All human induced pluripotent stem cell lines showed terminal maturation into normoblasts and enucleated reticulocytes, producing predominantly fetal hemoglobin. Differences were only observed in the growth rate of erythroid cells, which was slightly higher in the induced pluripotent stem cells derived from CD34(+) hematopoietic stem cells. More detailed methylation analysis of the hematopoietic and erythroid promoters identified similar CpG methylation levels in the induced pluripotent stem cell lines derived from CD34(+) cells and those derived from neural stem cells, which confirms their comparable erythroid differentiation potential.

MicroRNAs miR-26a, miR-26b, and miR-29b accelerate osteogenic differentiation of unrestricted somatic stem cells from human cord blood.

BACKGROUND: MicroRNAs are a population of short non-coding RNAs with widespread negative regulatory impact on mRNA translation. Unrestricted somatic stem cells (USSC) are a rare population in human cord blood that can be induced into cells representative of all three germinal layers. Here we analyzed the functional impact of miRNAs on the osteogenic differentiation in USSC. RESULTS: Gene expression profiling identified 20 microRNAs that were consistently upregulated during osteogenic differentiation of two different USSC cell lines (SA5/73 and SA8/25). Bioinformatic target gene prediction indicated that among these microRNAs, miR-10a, -22, -26a, -26b, and -29b recognize transcripts that encode a set of proteins inhibiting osteogenesis. We subsequently verified osteo-inhibitory CDK6, CTNNBIP1, HDAC4, and TOB1 and osteo-promoting SMAD1 as targets of these microRNAs. In Western blot analyses demonstrated that endogenous levels of CDK6 and HDAC4 were downregulated during osteogenic differentiation of USSC and reduced following ectopic expression of miR-26a/b and miR-29b. In contrast, endogenous expression of SMAD1, targeted by miR-26a/b, was unaltered during osteogenic differentiation of USSC or following ectopic expression of miR-26a/b. Functional overexpression analyses using microRNA mimics revealed that miR-26a/b, as well as miR-29b strongly accelerated osteogenic differentiation of USSC as assessed by Alizarin-Red staining and calcium-release assays. CONCLUSIONS: miR-26a/b and miR-29b are upregulated during osteogenic differentiation of USSC and share target genes inhibiting osteogenesis. Furthermore, these microRNAs accelerate osteogenic differentiation, likely mediated by osteo-inhibitory proteins such as CDK6 and HDAC4.

Significant clinical, neuropathological and behavioural recovery from acute spinal cord trauma by transplantation of a well-defined somatic stem cell from human umbilical cord blood.

Stem cell therapy is a potential treatment for spinal cord injury and different stem cell types have been grafted into animal models and humans suffering from spinal trauma. Due to inconsistent results, it is still an important and clinically relevant question which stem cell type will prove to be therapeutically effective. Thus far, stem cells of human sources grafted into spinal cord mostly included barely defined heterogeneous mesenchymal stem cell populations derived from bone marrow or umbilical cord blood. Here, we have transplanted a well-defined unrestricted somatic stem cell isolated from human umbilical cord blood into an acute traumatic spinal cord injury of adult immune suppressed rat. Grafting of unrestricted somatic stem cells into the vicinity of a dorsal hemisection injury at thoracic level eight resulted in hepatocyte growth factor-directed migration and accumulation within the lesion area, reduction in lesion size and augmented tissue sparing, enhanced axon regrowth and significant functional locomotor improvement as revealed by three behavioural tasks (open field Basso-Beattie-Bresnahan locomotor score, horizontal ladder walking test and CatWalk gait analysis). To accomplish the beneficial effects, neither neural differentiation nor long-lasting persistence of the grafted human stem cells appears to be required. The secretion of neurite outgrowth-promoting factors in vitro further suggests a paracrine function of unrestricted somatic stem cells in spinal cord injury. Given the highly supportive functional characteristics in spinal cord injury, production in virtually unlimited quantities at GMP grade and lack of ethical concerns, unrestricted somatic stem cells appear to be a highly suitable human stem cell source for clinical application in central nervous system injuries.

The BCR-ABL1 kinase bypasses selection for the expression of a pre-B cell receptor in pre-B acute lymphoblastic leukemia cells.

The BCR-ABL1 kinase expressed in acute lymphoblastic leukemia (ALL) drives malignant transformation of human pre-B cells. Comparing genome-wide gene expression profiles of BCR-ABL1+ pre-B ALL and normal bone marrow pre-B cells by serial analysis of gene expression, many genes involved in pre-B cell receptor signaling are silenced in the leukemia cells. Although normal pre-B cells are selected for the expression of a functional pre-B cell receptor, BCR-ABL1+ ALL cells mostly do not harbor a productively rearranged IGH allele. In these cases, we identified traces of secondary VH gene rearrangements, which may have rendered an initially productive VH region gene nonfunctional. Even BCR-ABL1+ ALL cells harboring a functional VH region gene are unresponsive to pre-B cell receptor engagement and exhibit autonomous oscillatory Ca2+ signaling activity. Conversely, leukemia subclones surviving inhibition of BCR-ABL1 by STI571 restore responsiveness to antigen receptor engagement and differentiate into immature B cells expressing immunoglobulin light chains. BCR-ABL1 kinase activity is linked to defective pre-B cell receptor signaling and the expression of a truncated isoform of the pre-B cell receptor-associated linker molecule SLP65. Also in primary leukemia cells, truncated SLP65 is expressed before but not after treatment of the patients with STI571. We conclude that inhibition of BCR-ABL1 reconstitutes selection for leukemia cells expressing a functional (pre-) B cell receptor.

Nucleolin as activator of human papillomavirus type 18 oncogene transcription in cervical cancer.

High risk human papillomaviruses (HPVs) are central to the development of cervical cancer and the deregulated expression of high risk HPV oncogenes is a critical event in this process. Here, we find that the cell protein nucleolin binds in a sequence-specific manner to the HPV18 enhancer. The DNA binding activity of nucleolin is primarily S phase specific, much like the transcription of the E6 and E7 oncoproteins of HPV18 in cervical cancer cells. Antisense inactivation of nucleolin blocks E6 and E7 oncogene transcription and selectively decreases HPV18(+) cervical cancer cell growth. Furthermore, nucleolin controls the chromatin structure of the HPV18 enhancer. In contrast, HPV16 oncogene transcription and proliferation rates of HPV16(+) SiHa cervical cancer cells are independent of nucleolin activity. Moreover, nucleolin expression is altered in HPV18(+) precancerous and cancerous tissue from the cervix uteri. Whereas nucleolin was homogeneously distributed in the nuclei of normal epithelial cells, it showed a speckled nuclear phenotype in HPV18(+) carcinomas. Thus, the host cell protein nucleolin is directly linked to HPV18-induced cervical carcinogenesis.

A new human somatic stem cell from placental cord blood with intrinsic pluripotent differentiation potential.

Here a new, intrinsically pluripotent, CD45-negative population from human cord blood, termed unrestricted somatic stem cells (USSCs) is described. This rare population grows adherently and can be expanded to 10(15) cells without losing pluripotency. In vitro USSCs showed homogeneous differentiation into osteoblasts, chondroblasts, adipocytes, and hematopoietic and neural cells including astrocytes and neurons that express neurofilament, sodium channel protein, and various neurotransmitter phenotypes. Stereotactic implantation of USSCs into intact adult rat brain revealed that human Tau-positive cells persisted for up to 3 mo and showed migratory activity and a typical neuron-like morphology. In vivo differentiation of USSCs along mesodermal and endodermal pathways was demonstrated in animal models. Bony reconstitution was observed after transplantation of USSC-loaded calcium phosphate cylinders in nude rat femurs. Chondrogenesis occurred after transplanting cell-loaded gelfoam sponges into nude mice. Transplantation of USSCs in a noninjury model, the preimmune fetal sheep, resulted in up to 5% human hematopoietic engraftment. More than 20% albumin-producing human parenchymal hepatic cells with absence of cell fusion and substantial numbers of human cardiomyocytes in both atria and ventricles of the sheep heart were detected many months after USSC transplantation. No tumor formation was observed in any of these animals.

Suppression of cellular immunity by cord blood-derived unrestricted somatic stem cells is cytokine-dependent.

Unrestricted somatic stem cells (USSC) have the potential to differentiate into tissues derived from all three germinal layers and therefore hold promise for use in regenerative therapies. Furthermore, they have haematopoietic stromal activity, a characteristic that may be exploited to enhance haematopoietic engraftment. Both applications may require USSC to be used in an allogeneic, HLA-mismatched setting. We have therefore studied their in vitro interaction with cellular immunity. USSC showed no allostimulatory activity and caused only minimal inhibition of allogeneic T-cell responses. However, following pre-stimulation with IFNgamma and TNFalpha, they inhibited T-cell proliferation in an indoleamine 2, 3-dioxygenase-dependent manner and suppressed graft-versus-host type reactions. In addition, USSC inhibited DC maturation and function. This inhibition was overridden by stronger DC maturation signals provided by IL-1beta, IL-6, PGE(2) and TNFalpha compared to TNFalpha alone. Pre-stimulation of USSC with IFNgamma and TNFalpha had a similar effect: Inhibition of DC maturation was no longer observed. Thus, USSC are conditionally immunosuppressive, and IFNgamma and TNFalpha constitute a switch, which regulates their immunological properties. They either suppress T-cell responses in the presence of both cytokines or in their absence block DC differentiation and function. These activities may contribute to fine-tuning the immune system especially at sites of tissue damage in order to ensure appropriate differentiation of USSC and subsequent tissue repair. Therapeutically, they may help to protect USSC and possibly their progeny from immune rejection.

Unrestricted somatic stem cells from human umbilical cord blood can be differentiated into neurons with a dopaminergic phenotype.

Recently, it has been shown that human unrestricted somatic stem cells (USSCs) from umbilical cord blood represent pluripotent, neonatal, nonhematopoietic stem cells with the potential to differentiate into the neural lineage. However, molecular and functional characterization of the neural phenotype and evaluation of the degree of maturity of the resulting cells are still lacking. In this study, we addressed the question of neuronal differentiation and maturation induced by a defined composition of growth and differentiation factors (XXL medium). We demonstrated the expression of different neuronal markers and their enrichment in USSC cultures during XXL medium incubation. Furthermore, we showed enrichment of USSCs expressing tyrosine hydroxylase (TH), an enzyme specific for dopaminergic neurons and other catecholamine-producing neurons, accompanied by induction of Nurr1, a factor regulating dopaminergic neurogenesis. The functionality of USSCs has been analyzed by patch-clamp recordings and high-performance liquid chromatography (HPLC). Voltage-gated sodium-channels could be identified in laminin-predifferentiated USSCs. In addition, HPLC analysis revealed synthesis and release of the neurotransmitter dopamine by USSC-derived cells, thus correlating well with the detection of TH transcripts and protein. This study provides novel insight into the potential of unrestricted somatic stem cells from human umbilical cord blood to acquire a neuronal phenotype and function.

Pegylated granulocyte colony-stimulating factor mobilizes CD34+ cells with different stem and progenitor subsets and distinct functional properties in comparison with unconjugated granulocyte colony-stimulating factor.

BACKGROUND: Pegylated granulocyte colony-stimulating factor (G-CSF) has recently been introduced as a new compound for mobilization of CD34(+) hematopoietic stem and progenitor cells. In this study, we compared the molecular and functional characteristics of CD34(+) cells mobilized by pegylated G-CSF with those mobilized by unconjugated G-CSF. DESIGN AND METHODS: Gene expression of immunomagnetically enriched CD34(+) cells from leukapheresis products of patients who were given pegylated-G-CSF or unconjugated G-CSF was analyzed using Affymetrix HG Focus microarrays and quantitative reverse transcriptase polymerase chain reaction. Flow cytometry and fluorescence activated cell sorting was conducted to assess the CD34(+) subset composition and to obtain Lin(-), CD34(+), CD38(-) hematopoietic stem cells. Cell cycle assays and clonogenic assays were performed for functional corroboration. RESULTS: Pegylated G-CSF and unconjugated G-CSF mobilized CD34(+) and hematopoietic stem cells with different molecular phenotypes and functional properties. The CD34(+) cells mobilized by pegylated G-CSF had higher expression levels of genes indicative of early hematopoiesis, including HOXA9, MEIS1 and GATA3. We found lower expression of genes characteristic of erythroid and later stages of myeloid differentiation and a lower functional burst-forming unit erythroid/colony-forming unit-granulocyte-macrophage ratio. Consistently, greater numbers of hematopoietic stem cells and common myeloid progenitors and fewer megakaryocyte-erthrocyte progenitors were found in the pegylated-G-CSF-mobilized CD34(+) cells. Additionally, sorted pegylated-G-CSF-mobilized hematopoietic stem cells displayed higher expression of HOXA9 in comparison to G-CSF-mobilized hematopoietic stem cells. In line with the gene expression data, CD34(+) cells mobilized by pegylated G-CSF, as well as sorted hematopoietic stem cells, showed a significantly greater cell cycle activity. CONCLUSIONS: Stimulation with pegylated-G-CSF or G-CSF results in different expression of key regulatory genes and different functional properties of mobilized hematopoietic stem cells as well as their progeny, a finding that might be relevant for the application of these cells in blood stem cell transplantation.

Cellular signaling in normal and cancerous stem cells.

Self-renewing divisions of normal and cancerous stem cells are responsible for the initiation and maintenance of normal and certain cancerous tissues, respectively. Recent findings suggest that tumor surveillance mechanisms can reduce regenerative capacity and frequency of normal stem cells, thereby contributing to tissue aging. Signaling pathways promoting self-renewal of stem cells can also drive proliferation in cancer. The BMI-1 proto-oncogene is required for the maintenance of tissue-specific stem cells and is involved in carcinogenesis within the same tissues. BMI-1 promotes self-renewal of stem cells largely by interfering with two central cellular tumor suppressor pathways, p16(Ink4a)/retinoblastoma protein (Rb) and ARF/p53, whose disruption is a hallmark of cancer. Nucleolin, an Rb-associated protein, is abundant in proliferating cancerous cells and likely contributes to the maintenance of human CD34-positive stem/progenitor cells of hematopoiesis. Elucidation of the involvement of proto-oncogenes and tumor suppressors in the maintenance of stem cells might have therapeutic implications.

Comparative generation and characterization of pluripotent unrestricted somatic stem cells with mesenchymal stem cells from human cord blood.

OBJECTIVE: Generation and expansion of pluripotent unrestricted somatic stem cells (USSCs) and mesenchymal cells (MSCs) from human cord blood as well their functional characterization were assessed. METHODS: USSC generation was initiated from fresh and cryopreserved cord blood (CB). Culture conditions and functional assays distinguishing between USSCs and MSCs (e.g., endodermal differentiation) are described. RESULTS: USSC cultures were initiated from 573 placental CB samples with a total generation frequency of 35.4% (n = 203), whereas successful generation of USSCs from cryopreserved products was scare. Medium, dexamethasone, and the fetal calf serum source are the major parameters to generate and expand the cells in a pluripotent state (osteogeneic, neural, and endodermal differentiation). CONCLUSIONS: USSC or MSC cultures can be easily obtained from fresh CB samples, good manufacturing practice production of such cells is feasible. These USSCs or MSCs from CB, when matched for HLA antigens, may serve as an allogeneic stem cell source for the development of cellular therapy for tissue repair.

Comparison of rapidly cycled tandem high-dose chemotherapy plus peripheral-blood stem-cell support versus dose-dense conventional chemotherapy for adjuvant treatment of high-risk breast cancer: results of a multicentre phase III trial.

BACKGROUND: Breast cancer with extensive axillary-lymph-node involvement has a poor prognosis after conventional treatment. In trials with historical controls, high-dose chemotherapy produced improved outcomes. We compared an intensive double-cycle high-dose chemotherapy regimen with an accelerated conventionally dosed regimen in high-risk breast cancer in a multicentre trial. METHODS: Patients with at least nine positive nodes were randomly assigned either two courses of accelerated (2-week intervals, with filgrastim support), conventionally dosed epirubicin and cyclophosphamide followed by two courses of high-dose chemotherapy (epirubicin, cyclophosphamide, and thiotepa supported by peripheral-blood progenitors) or four identical cycles of epirubicin and cyclophosphamide followed by three cycles of accelerated cyclophosphamide, methotrexate, and fluorouracil. The primary endpoint was event-free survival. Analyses were done both by intention to treat and per protocol. FINDINGS: 403 patients were enrolled; 201 were assigned high-dose chemotherapy and 202 conventional treatment. The mean number of positive nodes was 17.6, and median follow-up was 48.6 months. 4-year event-free survival (intention-to-treat analysis) was 60% (95% CI 53-67) in the high-dose chemotherapy group and 44% (37-52) in the control group (p=0.00069). The corresponding overall survival was 75% (69-82) versus 70% (64-77; p=0.02). There were no treatment-related deaths. INTERPRETATION: Our finding of significant improvements in both event-free and overall survival for high-dose chemotherapy compared with a dose-dense conventional regimen contrasts with the results of other studies. The discrepancy might be due partly to design differences (tandem, brief induction) between our regimen and those studied in other trials. This approach merits further study.

Nucleofection, an efficient nonviral method to transfer genes into human hematopoietic stem and progenitor cells.

The targeted manipulation of the genetic program of single cells as well as of complete organisms has strongly enhanced our understanding of cellular and developmental processes and should also help to increase our knowledge of primary human stem cells, e.g., hematopoietic stem cells (HSCs), within the next few years. An essential requirement for such genetic approaches is the existence of a reliable and efficient method to introduce genetic elements into living cells. Retro- and lentiviral techniques are efficient in transducing primary human HSCs, but remain labor and time consuming and require special safety conditions, which do not exist in many laboratories. In our study, we have optimized the nucleofection technology, a modified electroporation strategy, to introduce plasmid DNA into freshly isolated human HSC-enriched CD34(+) cells. Using enhanced green fluorescent protein (eGFP)-encoding plasmids, we obtained transfection efficiencies of approximately 80% and a mean survival rate of 50%. Performing functional assays using GFU-GEMM and long-term culture initiating cells (LTC-IC), we demonstrate that apart from a reduction in the survival rate the nucleofection method itself does not recognizably change the short- or long-term cell fate of primitive hematopoietic cells. Therefore, we conclude, the nucleofection method is a reliable and efficient method to manipulate primitive hematopoietic cells genetically.

Unrelated cord blood transplants in adults with hematologic malignancies.

BACKGROUND AND OBJECTIVES: We analyzed outcomes and risk factors after unrelated cord blood transplantation (CBT) in adults with hematologic malignancies. DESIGN AND METHODS: One hundred and seventy-one patients were transplanted after 1997. Their median age was 29 years (15-55), and the median follow-up time was 18 months (1-71). Most patients had acute or chronic leukemia (n=142, 83%), 91 (53%) were transplanted in advanced phase and an autologous transplant had failed in 32 (19%). Most patients (87%) received an HLA-mismatched cord blood unit with 1-2 HLA disparities. At infusion, the median number of nucleated cells and CD34(+) cells was 2.1x10(7)/kg and 1x10(5)/kg, respectively RESULTS: The cumulative incidence of neutrophil recovery at day 60 was 72+/-3% with a median of 28 days (11-57). A higher neutrophil count and use of hematopoietic growth factors were independently associated with faster neutrophil recovery. The cumulative incidence of grade II-IV acute graft-versus-host disease was 32+/-4% and this complication was not associated with the number of HLA mismatches. The 2-year cumulative incidence of chronic graft-versus-host disease, transplant related-mortality and relapse were 36+/-10%, 51+/-4% and 22+/-4%, respectively. At 2-years, disease-free-survival for patients transplanted in early, intermediate and advanced phases of disease was 41+/-9%, 34+/-10% and 18+/-4%, respectively. In multivariate analyses, advanced disease status was an adverse factor for relapse and disease-free survival. INTERPRETATION AND CONCLUSIONS: Unrelated CBT is a clear alternative for adults with hematological malignancies lacking an HLA-matched related or unrelated donor. The choice of units containing a higher neutrophil count and a policy of earlier transplantation are likely to provide better results.

Cellular immunity of patients with malignant glioma: prerequisites for dendritic cell vaccination immunotherapy.

OBJECT: Vaccination therapy that uses dendritic cells (DCs) is a promising immunotherapeutic approach. However, it relies on intact cellular immunity and efficient generation of mature DCs, both of which can be impaired in patients with glioma. Therefore, the immune status and ex vivo generation of DC in such patients were studied. METHODS: The frequencies of white blood cell subsets and monocyte-derived, mature DCs in patients with high-grade gliomas and healthy control volunteers were analyzed using flow cytometry. In the patients, frequencies of lymphocytes, T cells, and B cells were reduced in comparison with the volunteers in the control group, whereas frequencies of neutrophils and monocytes were increased. There were no differences between the two groups in terms of white blood cell counts or the frequency of NK cells and the major T-cell subsets. The responsiveness of T cells to lectin stimulation was normal. For monocytes, lower frequencies of CD80+ and CD86+ cells but not of CD40+ and HLA-DR+ cells were observed in patients. Ex vivo DC generation in a two-step culture protocol in autologous plasma-supplemented medium or in serum-free medium showed only minor differences in CD80 and HLA-DR expression between the patient and control groups. Frequencies of CD83+, CD1a+, CD14-, CD40+, and CD86+ cells were comparable. Overall, the serum-free medium was superior to the plasma-supplemented medium and allowed efficient ex vivo generation of CD83+, CD1a+, and CD14- mature DCs. CONCLUSIONS: Only minor defects in the immune status of patients with glioma were observed, which probably would not hamper immunotherapy. Mature DCs can be generated successfully in normal numbers and with typical immunophenotypes from monocytes of patients with glioma, particularly under serum-free conditions.

[Transplantation of autologous adult bone marrow stem cells in patients with severe peripheral arterial occlusion disease]. / Transplantation von autologen adulten Knochenmarkstammzellen bei Patienten mit schwerer peripherer arterieller Verschlusskrankheit.

BACKGROUND: For many patients with severe peripheral arterial occlusion disease (PAOD) an interventional or surgical treatment is not feasible. The regenerative potential of adult autologous mononuclear stem cells could contribute to neoangiogenesis. PATIENTS AND METHODS: Ten patients with severe PAOD were included. The walking distance was < 200 m and no interventional or surgical treatment was possible. After harvesting of 80 ml of bone marrow the mononuclear cell fraction was separated. Thereafter, intraarterial (10 ml into the common femoral artery) and intramuscular (5 ml into the muscles of the thigh and the lower leg) transplantation of the cell suspension was performed. RESULTS: After 2 months the walking distance was enhanced significantly in all patients. Furthermore, a significant improvement of ankle-brachial index at rest, capillary-venous oxygen saturation and parameters of venous occlusion plethysmography was seen. No complications or side effects could be monitored. CONCLUSION: These results demonstrate, that the combined intraarterial and intramuscular transplantation of autologous adult bone marrow stem cells leads to a significant improvement of perfusion indices in patients with severe PAOD.

Cytokine production and hematopoiesis supporting activity of cord blood-derived unrestricted somatic stem cells.

OBJECTIVE: Cytokine production and hematopoiesis-supporting stromal activity of cord blood (CB)-derived unrestricted somatic stem cells (USSC) in comparison to bone marrow mesenchymal stem cells (BMMSC) and hematopoietic progenitor expansion solely driven by recombinant cytokines were assessed. METHODS: USSC generation was initiated from fresh and cryopreserved CB. Cytokine production by USSC and BMMSC was determined qualitatively by cytokine mRNA expression array analyses or quantitatively by Multiplex or ELISA analyses. To evaluate hematopoiesis-supporting activity, CB CD34+ cells were expanded in cocultures with USSC and BMMSC or in the presence of Flt3-L, SCF, and TPO. Expansion of CD34+ cells, total cells, colony-forming cells (CFC), and LTC-IC were determined after 1, 2, 3, and 4 weeks of culture. RESULTS: USSC constitutively produced SCF, LIF, TGF-1beta, M-CSF, GM-CSF, VEGF, IL-1beta, IL-6, IL-8, IL-11, IL-12, IL-15, SDF-1alpha, and HGF. When USSC were stimulated with IL-1beta, G-CSF was released. Production of SCF and LIF were significantly higher in USSC compared to BMMSC. At 1, 2, 3, and 4 weeks, cocultivation of CD34+ cells on the USSC layer resulted in a 14.6-fold +/- 1.1-fold, 110.1-fold +/- 17.9-fold, 151.8-fold +/- 39.7-fold, and 183.6-fold +/- 40.4-fold amplification of total cells and in a 30.6-fold +/- 4.4-fold, 101.4-fold +/- 27.5-fold, 64.7-fold +/- 15.8-fold, and 29.4-fold +/- 3.1-fold amplification of CFC, respectively. LTC-IC expansion at 1 and 2 weeks was, with 2.0-fold +/- 0.1-fold and 2.5-fold +/- 0.3-fold, significantly higher for USSC than BMMSC (1.1-fold +/- 0.03-fold and 1.1-fold +/- 0.1-fold), but declined after day 21. Transwell cocultures of USSC did not significantly alter total cell or CFC expansion. CONCLUSIONS: USSC produce functionally significant amounts of hematopoiesis-supporting cytokines and are superior to BMMSC in expansion of CD34+ cells from CB. USSC is therefore a suitable candidate for stroma-driven ex vivo expansion of hematopoietic CB cells for short-term reconstitution.

Sp1 as G1 cell cycle phase specific transcription factor in epithelial cells.

Sp1 binding sites have been identified in enhancer/promoter regions of several growth and cell cycle regulated genes, and it has been shown that Sp1 is increasingly phosphorylated in G1 phase of the cell cycle. Interactions of Sp1 with proteins involved in control of cell cycle and tumor formation have been reported. Here we show that expression of Sp1 protein predominates in the G1 phase of the cell cycle in epithelial cells. This is achieved by proteasome-dependent degradation. Inhibition of endogeneous Sp1 activity by a dominant-negative Sp1 mutant was associated with a cell cycle arrest in G1 phase, a strongly reduced expression of cyclin D1, the EGF-receptor and increased levels of p27Kip1. We have thus identified Sp1 as an important regulator of the cell cycle in G1 phase.

Repair of infarcted myocardium by autologous intracoronary mononuclear bone marrow cell transplantation in humans.

BACKGROUND: Experimental data suggest that bone marrow-derived cells may contribute to the healing of myocardial infarction (MI). For this reason, we analyzed 10 patients who were treated by intracoronary transplantation of autologous, mononuclear bone marrow cells (BMCs) in addition to standard therapy after MI. METHODS AND RESULTS: After standard therapy for acute MI, 10 patients were transplanted with autologous mononuclear BMCs via a balloon catheter placed into the infarct-related artery during balloon dilatation (percutaneous transluminal coronary angioplasty). Another 10 patients with acute MI were treated by standard therapy alone. After 3 months of follow-up, the infarct region (determined by left ventriculography) had decreased significantly within the cell therapy group (from 30+/-13 to 12+/-7%, P=0.005) and was also significantly smaller compared with the standard therapy group (P=0.04). Likewise, infarction wall movement velocity increased significantly only in the cell therapy group (from 2.0+/-1.1 to 4.0+/-2.6 cm/s, P=0.028). Further cardiac examinations (dobutamine stress echocardiography, radionuclide ventriculography, and catheterization of the right heart) were performed for the cell therapy group and showed significant improvement in stroke volume index, left ventricular end-systolic volume and contractility (ratio of systolic pressure and end-systolic volume), and myocardial perfusion of the infarct region. CONCLUSIONS: These results demonstrate for the first time that selective intracoronary transplantation of autologous, mononuclear BMCs is safe and seems to be effective under clinical conditions. The marked therapeutic effect may be attributed to BMC-associated myocardial regeneration and neovascularization.