Researching glutamate – induced cytotoxicity in different cell lines: a comparative/collective analysis/study

Although glutamate is one of the most important excitatory neurotransmitters of the central nervous system, its excessive extracellular concentration leads to uncontrolled continuous depolarization of neurons, a toxic process called, excitotoxicity. In excitotoxicity glutamate triggers the rise of intracellular Ca2+ influx, followed by up regulation of nNOS, dysfunction of mitochondria, ROS production, ER stress and release of lysosomal enzymes. Excessive calcium concentration is the key mediator of glutamate toxicity through over activation of ionotropic and metabotropic receptors. In addition, glutamate accumulation can also inhibit cystine uptake by reversing the action of the cystine/glutamate antiporter. Reversal of the antiporter action reinforces the aforementioned events by depleting neurons of cysteine and eventually glutathione’s reducing potential. Various cell lines have been employed in the pursuit to understand the mechanism(s) by which excitotoxicity affects the cells leading them ultimately to their demise. In some cell lines glutamate toxicity is exerted mainly through over activation of NMDA, AMPA or Kainate receptors whereas in other cell lines lacking such receptors, the toxicity is due to glutamate induced oxidative stress. However in the greatest majority of the cell lines ionotropic-glutamate receptors are present, co-existing to cystine/glutamate antiporters and metabotropic glutamate receptors, supporting the assumption that excitotoxicity effect in these cells is accumulative. Different cell lines differ in their responses when exposed to glutamate. In this review article the responses of PC12, SH-SY5Y, HT-22, NT-2, OLCs, C6, primary rat cortical neurons, RGC-5 and SCN2.2 cell systems are systematically collected and analyzed

Alcian Blue Histological investigation of generated hyaline cartilage tissue from adipose mesenchymal stem cells, on Polycaprolactone scaffolds.

Purpose: Cartilage has a low regenerative capacity and research has recently focused on regenerative medicine and the construction of three-dimensional scaffolds for cartilage production. The aim of the study was to compare three types of polycaprolactone scaffolds (PCLs) and to characterize the produced cells as chondrocytes, using Alcian blue, a widespread histochemical staining. Methods: We manufactured polycaprolactone scaffolds with three different geometry patterns, named PCL1, PCL2 and PCL3. Adipose mesenchymal stem cells ADMSCs were harvested and were cultivated on all scaffolds. After 26 days of culture, scaffolds were histologically examined. Results: Chondrocytes and extracellular material in scaffolds were revealed by alcian blue staining. In all three types of scaffolds extracellular matrix high in proteoglycans was produced. Small cells were usually found in three-dimensional, tight groups. Larger cells were often identified in flat groups with more extracellular material. In PCL2 scaffolds, cells were usually more rounded and often appeared to be inside lacunae. Perichondrium was detected. Conclusion: Chondrogenesis was achieved in all three types of scaffolds. In all cases we identified cells at various stages of maturation. In the PCL2 scaffold, cells appeared more mature, suggesting that this type of scaffold may be a little more favorable for chondrogenesis

An indirect negative autoregulatory mechanism involved in hepatocyte nuclear factor-1 gene expression.

Recent studies have revealed that hepatocyte nuclear factor 4 (HNF-4) is an essential positive regulator of another liver enriched transcription factor HNF-1, defining a transcriptional hierarchy between the two factors operating in hepatocytes. To assess the possible autoregulation of the HNF-1 gene we have examined the effect of HNF-1 on its own transcription. In transient transfection assays, HNF-1 strongly down-regulated transcription driven by its own promoter in HepG2 cells. In addition HNF-1 also repressed the activity of HNF-4 dependent ApoCIII and ApoAI promoters. The same effect was observed using vHNF-1, a distinct but highly related protein to HNF-1. Both HNF-1 and vHNF-1 downregulated HNF-4 activated transcription from intact and chimeric promoter constructs carrying various HNF-4 binding sites implying that they act by impeding HNF-4 binding or activity. DNA binding and cell free transcription experiments however failed to demonstrate any direct or indirect interaction of HNF-1 and vHNF-1 with the above regulatory regions. Both factors repressed HNF-4 induced transcription of the ApoCIII and HNF-1 genes in HeLa cells, arguing against the requirement of a hepatocyte specific function. These findings define an indirect negative autoregulatory mechanism involved in HNF-1 gene expression, which in turn may affect HNF-4 dependent transcription of other liver specific genes

Supporting Remote Sensing Research with Small Unmanned Aerial Systems

We describe several remote sensing research projects supported with small Unmanned Aerial Systems (sUAS) operated by the NGA Basic and Applied Research Office. These sUAS collections provide data supporting Small Business Innovative Research (SBIR), NGA University Research Initiative (NURI), and Cooperative Research And Development Agreements (CRADA) efforts in addition to inhouse research. Some preliminary results related to 3D electro-optical point clouds are presented, and some research goals discussed. Additional details related to the autonomous operational mode of both our multi-rotor and fixed wing small Unmanned Aerial System (sUAS) platforms are presented