Journal of Stem Cells最新文献

Nearly 2 million people annually die prematurely from various illness contributed by indoor air pollutants (IAP). Such pollutants affect the lungs leading to diseases ranging from bronchial diseases to malignant lung cancer. Stem cells (SC) with the property of self-renewal, pluripotency, and capability of homing into tumors and metastases, have been reported to be promising in treatment of lung cancer. In this review, we have tried to understand the role of components of IAP affect the SC. Although very few studies have been conducted in these lines, existing reports suggest that IAP causes damage to stem cells and their niches thereby reducing successful chances of autologous stem cell transplantation and therapy. The mechanism by which components of IAP affects the functioning of stem cells thus conferring toxicity remains unexplored. The future scope of this review lies in revealing answer to underlying questions of repair and modulation of stem cells in therapeutic treatment of lung diseases.

The aim of this study was to evaluate human adipose-derived stem cells (ASCs) from passage 2 (P2) to P8 cultured in medium containing 5% autologous serum (AS) after a long-term cryopreservation with regards to their surface marker expression, differentiation potential, and immunosuppressive effect in vitro. 8-color flow cytometry and real time PCR were used to determine mesenchymal stem cell (MSC) surface marker expression on ASCs from various passages. In vitro differentiation ability and immunomodulatory properties of ASCs were also tested. Flow cytometry showed that all ASCs express typical MSC markers CD29, CD44, CD73, CD90, CD105 simultaneously, but do not express such markers as HLA-DR, CD34, CD14, CD19, and CD45. Furthermore, median fluorescence intensity of positive cell surface markers increased with each subsequent passage indicating the accumulation of protein expression. The multilineage differentiation demonstrated the ability of ASCs from P6 to efficiently differentiate into adipocytes and chondrocytes, but their potential of osteogenic differentiation was diminished. Data from co-culture of ASCs and autologous peripheral blood mononuclear cells (PBMNCs) indicated that ASCs from P3, P6, and P9 significantly reduce the proliferation of PBMNCs at ASCs:PBMNCs ratio 1:1 and this suppression is dose dependent. This study demonstrated that ASCs from P2 to P8, cultured in the presence of AS, represent a highly homogeneous cell population with a peak accumulation of MSC surface proteins at P5 possessing multilineage differentiation ability and significant immunosuppressive properties after double freezing and more than 4 years of cryopreservation.

Endothelial Progenitor Cells (EPCs) are bone-marrow derived stem cells that are postulated to contribute to post-natal vasculogenesis and to repair of damaged endothelium by incorporation into the vessel wall, secretion of paracrine hormones and stimulation of angiogenesis. Since the first description of the putative EPCs in 1997, and the role of these cells in neovascularisation of mouse and rabbit ischaemic limbs was originally described, there has been an explosion of research into the role of EPCs in human cardiovascular disease. There is now a large body of direct and indirect evidence to support an important role for EPCs in cardiovascular disease processes. This book chapter explores the following: 1. Correlation between EPCs and other cardiovascular risk markers 2. EPCs in patients with established cardiovascular disease 3. Reversible defects in EPC number and function in patients with an increased cardiovascular risk 4. Statins and EPC biology 5. The effect on EPCs of other interventions known to reduce cardiovascular risk - EPCs and treatment of diabetes, hypertension, subclinical hypothyroidism 6. Beneficial effects of EPC-based therapies animal models of ischaemia 7. Human Studies of EPC-based therapies A lower level of circulating EPCs and reduced EPC function in vitro are associated with an increased cardiovascular risk. The accumulated evidence suggests that a balance between the damaging effects of conventional cardiovascular risk factors and the ability of circulating EPCs to affect endothelial repair determines this cardiovascular risk.

Blood pharming is a recently designed concept to enable in vitro production of blood cells that are safe, effective and readily available. This approach represents an alternative to blood donation and may contribute to overcome the shortage of blood products. However, the high variability of the human leukocyte antigen (HLA) loci remains a major hurdle to the application of off-the-shelf blood products. Refractoriness to platelet (PLT) transfusion caused by alloimmunization against HLA class I antigens constitutes a relevant clinical problem. Thus, it would be desirable to generate PLT units devoid of HLA antigens. To reduce the immunogenicity of cell-based therapeutics, we have permanently reduced HLA class I expression using an RNA interference strategy. Furthermore, we demonstrated that the generation of HLA class I-silenced (HLA-universal) PLTs from CD34+ progenitor cells using an shRNA targeting β2-microglobulin transcripts is feasible. CD34+ progenitor cells derived from G-CSF mobilised donors were transduced with a lentiviral vector encoding for the β2-microglobulin-specific shRNA and differentiated into PLTs using a liquid culture system. The functionality of HLA-silenced PLTs and their ability to escape HLA antibody-mediated cytotoxicity were evaluated in vitro and in vivo. Platelet activation in response to ADP and thrombin were assessed in vitro. The immune-evasion capability of HLA-universal megakaryocytes (MKs) and PLTs was tested in lymphocytotoxicity assays using anti-HLA antibodies. To assess the functionality of HLA-universal PLTs in vivo, HLA-silenced MKs were infused into NOD/SCID/IL-2Rγc(-/-) mice with or without anti-HLA antibodies. PLT generation was evaluated by flow cytometry using anti-CD42a and CD61 antibodies. HLA-universal PLTs demonstrated to be functionally similar to blood-derived PLTs. Lymphocytotoxicity assays showed that HLA-silencing efficiently protects MKs against HLA antibody-mediated complement-dependent cytotoxicity. 80-90% of HLA-expressing MKs, but only 3% of HLA-silenced MKs were lysed. In vivo, both HLA-expressing and HLA-silenced MKs showed human PLT production (up to 0.5% within the PLT population) when anti-HLA antibodies were absent. However, in presence of anti-HLA antibodies HLA-expressing MKs were rapidly cleared from the circulation of mice, while HLA-silenced MKs escaped HLA antibody-mediated cytotoxicity and human PLT production was detectable up to 11 days. Our studies show that HLA-silenced PLTs are functional and efficiently protected against HLA antibody-mediated cytotoxicity. In this chapter, we provide a review of our most recent findings in the use of CD34+ progenitor cells for the production of HLA-universal PLTs and their potential clinical applications. Provision of HLA-universal PLT units may become an important component in the management of patients with PLT transfusion refractoriness.

Regenerative medicine with the promise of complete organ restoration could change the treatment paradigm for various degenerative disorders. In order to develop successful, safe and efficient regenerative therapies, appropriate amount of pluripotent autologous cells are desired. Pluripotent stem cell lines, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), offer a unique opportunity to derive various cell types that can be exploited for regenerative medicine. However, their application in therapies is limited due to inherent potential tumorigenesis, problems with immune-rejection, applied reprogramming methods, and ethical considerations. Recent reports on the establishment of very small embryonic-like cells (VSELs) are pointing to a way out of this dilemma, since it is proposed that these cells have similar characteristics as ESCs and could serve as basis for therapeutic applications. A careful scientific comparison of VSELs is now needed in order to make judgments about their capabilities and characteristics. In any case, the development of successful, safe and efficient regenerative therapies based on human pluripotent cells requires additional quality assessments of critical parameters that are also summarized within the review.

We have since the 1970's embarked on the development of biologically derived fluorophore-protein complexes that will find applications in the communicable and non-communicable disease etiology processes and their cures. We have since then become largely successful in these endeavors along with interspersed contributions also from investigators who have generally restricted to working in confined disciplines. Their encompassment with our works as this investigator has traversed his definitely chosen and not merely a circumstantial, coincidental, or accidental step-wise multi-disciplinary scientific path from biophysics to regenerative medicine spanning these lines of investigations for last four decades have finally yielded the much necessitated disease related applied biological interventions for human benefits. Taking a cue from our early investigations and findings on which we call attention to the identification and characterization of the use of the primary light-emitting lumazine precursor of riboflavin which is 6,7-dimethyl-8-ribityl lumazine-protein complex which we had derived from the bioluminescence bacterium (Photobacterium phosphoreum) wherein it functions as a naturally occurring fluorescence light emitter (LumP). These in vivo phenomena have been a precursor to the subsequent developments in vitro. This in vivo to in vitro investigation path of ours has been also comprised among others of binding of photosynthetic light-harvesting marine dinoflagellate algae (Glenodinium sp.) derived peridinin-chlorophyll a-protein (PerCP) complex-labeled monoclonal antibodies useful in the development of flow cytometry. These fluorescence labeled antibodies bound antigens which include those of communicable infectious diseases (HIV/AIDS - env-gp160, gag-p24), non-communicable but also potential hereditary and malignant disorders (Cancer/Tumor Markers - Melan-A/Mart-1 of melanoma), normal immune response cells (Human/Mouse/species cellular MHC/TCR/CD45/CD33/CD56/CD19/CD41), and of types of stem cells (CD34/CD38/c-Mpl/Oct4/Neuropilin-1/SOX17). Such antigens have been analyzed by us and other investigators by fluorescence-activated cell sorting (FACS - cell surface and intracellular binding), confocal fluorescence microscopy, or/and immunohistochemistry, to determine qualitative and quantitative antigen expression levels and their mechanistic implications. We have followed stem cell differentiation patterns and signaling mechanisms through marker antigen-antibody binding wherein the antibodies are labeled with covalently linked fluorophore-protein complexes or fluorescence emitting chromophores. These complexes among others also have included PerCP. We are also now in the process of developing flow cytometry applications of additional visible light emitting chromophore-protein complexes through industrial collaborations. The United States Navy has long been known for interest in the estimation of changes in illumination intensity in and under th

Breast cancer is a leading cause of deaths in humans. Mesenchymal stem cells (MSC) have been identified to possess powerful therapeutic properties in humans. The capability of MSC to migrate toward injured tissue suggests their potential in new clinical applications. The aim of this study was to investigate the potential role of adipose stem cells (ADSCs) for recovering cellular potential and delaying or treating breast cancer in an animals model of human breast cancer. Cellular adoptive immunotherapy using adipose derived mesenchymal stem cells tailored made for Breast Cancer patients would offer a new effective less invasive treatment method. ADSCs injected into the cancer tumor did not affect tumor growth and the cancer kept growing. ADSCs injected so that they surrounded the tumor decreased growth and the tumor had disappeared after 3 to 8 weeks and total recovery was maintained throughout the 6 months of study. The adipose stem cells are the "active" and "regenerative" part of fat. ADSCs may appear promising for their use as "secretor" of the supernatant substance against breast cancer cells.

Aim: Clonospheres formed due to modified culture conditions are often studied for their stem cell like behaviour. The main objective of the current study is to compare the stem cell markers and link it to hTERT levels by monitoring their quantitative gene expression as they are potential targets for new generation combination therapeutics.

Method: In the present study we created stable colonospheres of Human colon cancer cell line HCT-116 long term culture conditions of Serum deprivation. Clonospheres formed after 15 days were collected by gentle and enzymatic dissociation was performed. Single cell suspension was obtained by mechanically dissociating the cells through a 22G needle. Single cells were replanted at a density 1200 cells/ml in Serum Free Medium in the 6 well plates for further passage. Passaging of cells was done at an interval of 8 days. The spheres formed were cyto-spun in special slides for Immunocytochemistry (ICC) studies for β-catenin protein and hTERT. The colonospheres were also processed for real time PCR expression studies for the same genes to confirm.

Results: In this present study, immunofluorescence studies revealed high β-catenin expression in the nucleus in colonospheres as compared to that of differentiated cancer cell line HCT-116 where the signal was localized mostly in the membranous and non-nuclear regions. Also increased TRF2 signal in colonospheres indicated higher activity of hTERT gene as TRF2 is the direct activator of hTERT to protect the telomere. Quantitative PCR studies showed that there was a significant over expression (p<0.05) at the mRNA level of the hTERT, TRF2, Rap1 genes along with the β-catenin over expression. Immunofluorescence analysis also revealed higher expression of CSC marker CD44 and ALDH1in colonospheres compared to the parental population.

Conclusion: Clonospheres sub-population is showing higher degree of hTERT gene expression along with β-catenin when compared to the parental HCT-116 cancer cells. We also checked the co expression of other telomere maintenance genes mainly TRF 2 and Rap1 which also showed similar results. Therefore, we conclude that not only hTERT but possibly other Sheltrin proteins are regulated by β-catenin which is co expressed.

Cancer stem cells (CSCs) are defined by their innate stem cell like properties and can be identified by specific markers that include antigens, molecules and signaling pathways. Like stem cells, CSC divide indefinitely giving rise to both more CSCs and differentiated cell progeny. CSCs can give rise to tumors that phenotypically resemble their origin, either morphologically or by expression of tissue specific genes. Tumors arise from a single cell, the CSC, but the cells that constitute the tumor are not identical to each other. Evidence of heterogeneous populations within a tumor has led to an investigation of the cellular hierarchy of cancers. This review gives an overview of cancer stem cells, from breast, cervical, lung, prostate, head and neck, glioblastoma, pancreatic and colorectal cancers and mechanisms implicated in tumor development and therapeutic interventions.