Enteric Neurospheres Are Not Specific to Neural Crest Cultures: Implications for Neural Stem Cell Therapies

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Tissue engineering, stem cells, cloning, and parthenogenesis: new paradigms for therapy

Patients suffering from diseased and injured organs may be treated with transplanted organs. However, there is a severe shortage of donor organs which is worsening yearly due to the aging population. Scientists in the field of tissue engineering apply the principles of cell transplantation, materials science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Both therapeutic cloning (nucleus from a donor cell is transferred into an enucleated oocyte), and parthenogenesis (oocyte is activated and stimulated to divide), permit extraction of pluripotent embryonic stem cells, and offer a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy. The present article reviews recent progress in tissue engineering and describes applications of these new technologies that may offer novel therapies for patients with end-stage organ failure

Optimisation of Biochemical Condition and Substrates In Vitro for Tissue Engineering of Ligament

In this work, we analysed the effect of growth factors on in vitro cell proliferation and collagens synthesis by fibroblasts cultured for 72 h on different substrates (silicon sheet with or without 1% gelatin, and glass as control surface) for ligament tissue engineering. A human fibroblast cell line (CRL-2703) was used. The synthesis of type I and type III collagens were evaluated qualitatively and quantitatively by RT-PCR and confocal microscopy, respectively. Cell proliferation was evaluated by two methods: (1) MTT assay (2) cell cycle analysis. It was found that PDGF-AB stimulate the proliferation of fibroblast cultured on gelatin coated silicon sheet in dose dependant manner with a maximum effect at 10 ng ml(−1). The exogenous TGF-β1 induced the expression of type I and type III collagens in a dose and substrate-dependant manner. We deduce from this work that biochemical conditions and substrates have an important impact for optimisation of the tissue neo synthesis

Venous Graft-Derived Cells Participate in Peripheral Nerve Regeneration

Background: Based on growing evidence that some adult multipotent cells necessary for tissue regeneration reside in the walls of blood vessels and the clinical success of vein wrapping for functional repair of nerve damage, we hypothesized that the repair of nerves via vein wrapping is mediated by cells migrating from the implanted venous grafts into the nerve bundle. Methodology/Principal Findings: To test the hypothesis, severed femoral nerves of rats were grafted with venous grafts from animals of the opposite sex. Nerve regeneration was impaired when decellularized or irradiated venous grafts were used in comparison to untreated grafts, supporting the involvement of venous graft-derived cells in peripheral nerve repair. Donor cells bearing Y chromosomes integrated into the area of the host injured nerve and participated in remyelination and nerve regeneration. The regenerated nerve exhibited proper axonal myelination, and expressed neuronal and glial cell markers. Conclusions/Significance: These novel findings identify the mechanism by which vein wrapping promotes nerve regeneration. © 2011 Lavasani et al

Integration of Transcriptomics, Proteomics, and MicroRNA Analyses Reveals Novel MicroRNA Regulation of Targets in the Mammalian Inner Ear

We have employed a novel approach for the identification of functionally important microRNA (miRNA)-target interactions, integrating miRNA, transcriptome and proteome profiles and advanced in silico analysis using the FAME algorithm. Since miRNAs play a crucial role in the inner ear, demonstrated by the discovery of mutations in a miRNA leading to human and mouse deafness, we applied this approach to microdissected auditory and vestibular sensory epithelia. We detected the expression of 157 miRNAs in the inner ear sensory epithelia, with 53 miRNAs differentially expressed between the cochlea and vestibule. Functionally important miRNAs were determined by searching for enriched or depleted targets in the transcript and protein datasets with an expression consistent with the dogma of miRNA regulation. Importantly, quite a few of the targets were detected only in the protein datasets, attributable to regulation by translational suppression. We identified and experimentally validated the regulation of PSIP1-P75, a transcriptional co-activator previously unknown in the inner ear, by miR-135b, in vestibular hair cells. Our findings suggest that miR-135b serves as a cellular effector, involved in regulating some of the differences between the cochlear and vestibular hair cells

The expression of Clcn7 and Ostm1 in osteoclasts is coregulated by microphthalmia transcription factor

Microphthalmia transcription factor (MITF) regulates osteoclast function by controling the expression of genes, including tartrate-resistant acid phosphatase (TRAP) and cathepsin K in response to receptor activator of nuclear factor-kappa B ligand (RANKL)-induced signaling. To identify novel MITF target genes, we have overexpressed MITF in the murine macrophage cell line RAW264.7 subclone 4 (RAW/C4) and examined the gene expression profile after sRANKL-stimulated osteoclastogenesis. Microarray analysis identified a set of genes superinduced by MITF overexpression, including Clcn7 (chloride channel 7) and Ostm1 (osteopetrosis-associated transmembrane protein 1). Using electrophoretic mobility shift assays, we identified two MITF-binding sites (M-boxes) in the Clcn7 promoter and a single M-box in the Ostm1 promoter. An anti-MITF antibody supershifted DNA-protein complexes for promoter sites in both genes, whereas MITF binding was abolished by mutation of these sites. The Clcn7 promoter was transactivated by coexpression of MITF in reporter gene assays. Mutation of one Clcn7 M-box prevented MITF transactivation, but mutation of the second MITF-binding site only reduced basal activity. Chromatin immunoprecipitation assays confirmed that the two Clcn7 MITF binding and responsive regions in vitro bind MITF in genomic DNA. The expression of Clcn7 is repressed in the dominant negative mutant Mitf mouse, mi/mi, indicating that the dysregulated bone resorption seen in these mice can be attributed in part to transcriptional repression of Clcn7. MITF regulation of the TRAP, cathepsin K, Clcn7, and Ostm1 genes, which are critical for osteoclast resorption, suggests that the role of MITF is more significant than previously perceived and that MITF may be a master regulator of osteoclast function and bone resorption

Mechanistic target of rapamycin inhition extend cellular lifespan in dendritic cells by preserving mitochondrial function

TLR-mediated activation of dendritic cells (DCs) is associated with a metabolic transition in which mitochondrial oxidative phosphorylation is inhibited by endogenously synthesized NO and the cells become committed to glucose and aerobic glycolysis for survival. We show that inhibition of mechanistic target of rapamycin (mTOR) extends the lifespan of TLR-activated DCs by inhibiting the induction of NO production, thereby allowing the cells to continue to use their mitochondria to generate ATP, and allowing them the flexibility to use fatty acids or glucose as nutrients to fuel core metabolism. These data provide novel mechanistic insights into how mTOR modulates DC metabolism and cellular longevity following TLR activation and provide an explanation for previous findings that mTOR inhibition enhances the efficacy of DCs in autologous vaccination