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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

EGF receptors are expressed on most fetal and adult cells but their precise roles are not well known. We previously reported that, in P19 embryonal carcinoma cells, the expression of kinase-negative EGFR inhibits retinoic acid (RA)-induced differentiation to nervous tissue, suggesting that EGFR plays a role in differentiation (J.-X. Wu and E. D. Adamson (1993) Dev. Biol. 159, 208-222). Embryo stem (ES) cells differentiate into a wide range of tissue types after the removal of the cytokine LIF from the culture medium. We demonstrate here that the induction of some early markers of differentiation, tissue-type plasminogen activator (tPA), AFP and keratins 8 and 19 is inhibited, whilst brachyury and myosin are increased, in clones containing kinase-negative mutant EGFR. After an extended period of differentiation, the cell types present in mutant and control cultures differed. Mutant clones produced frequent cardiac and skeletal muscle as the predominant differentiated cell types in vitro; other cells types were sparse or absent. Teratocarcinomas formed by EGFR-deltakinase-expressing ES cells contained frequent skeletal and cardiac muscle as well as apoptotic nuclei, while normal ES cells produced no detectable muscle and less apoptoses. Since mutant differentiated cultures had slower growth rates and increased levels of cell death, we concluded that: (1) inactive EGFR does not allow some cell types to survive and/or proliferate; (2) tissues that do not require EGFR for their survival, development or function predominate in long-term mutant cultures; (3) EGFR activity is not necessary for cardiac and skeletal muscle or endoderm formation and (4) Impaired survival of EGF-dependent lineages leads to preferential selection of muscle in differentiating ES cells.
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PMID:Kinase-negative mutant epidermal growth factor receptor (EGFR) expression during embryonal stem cell differentiation favours EGFR-independent lineages. 889 44

The phospholipid profiles of heart, kidney, and pectoral muscle of 7-day-old chicks and their in vitro response to the endogenous lipolytic enzymes (mainly in the phospholipase group) at pH 7.4 and 38 degrees C for 60 min were analysed by TLC technology and densitometry. The noticeable preferential deacylation of cardiolipin (CL) as detected by the formation of monolysocardiolipin (MLCL) and concurrent reduction of CL level were the most prevalent lipolytic events of chick cardiac muscle, but the least prevalent in chick pectoral muscle. Deacylation of ethanolamine plasmalogen (PE) as revealed by the formation of the corresponding lyso alkenyl derivative was also prominent in cardiac muscle, but much less so in kidney and none at all was detected in pectoral muscle. The level of sphingomyelin (SM) was much higher in kidney than heart and pectoral muscle. Following in vitro incubation, the reduction in the level of SM and the high level of ceramide (Cer) production were most conspicuous in kidney, less in cardiac muscle and least in pectoral muscle. The hydrolysis of PE and SM confirm the action of endogenous PLA(2) and endogenous sphingomyelinase on PE and SM respectively. These data clearly illustrate the differential response of the endogenous substrates (phospholipids) to the endogenous phospholipases of the tissues studied and are probably related to their physiological activities in vivo.
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PMID:Comparative studies of the endogenous phospholipids and their in vitro hydrolysis by endogenous phospholipases of various tissues from 7-day-old chicks: a thin layer chromatographic and densitometric analysis. 1537 32

A novel type of capillary channel fibers (CCFs) containing eight open grooves with depth of 5-15 microm and width of 10 microm were tested for their use in tissue engineering as matrices that provide topographical guidance to neo-tissue development. The matrices fabricated from fibers of poly(l-lactic acid) (PLA) and polyethylene terephthalate (PET) were seeded with rat skin fibroblasts (RSFs) and rat aortic smooth muscle cells (RASMCs) for up to 4 weeks. Cells attached and extended their cytoplasmic lamellapodia within the grooves. The cells were proliferating within the grooves and were highly aligned parallel to the direction of the grooves. RASMCs and RSFs showed highly aligned actin and vimentin cytoskeleton, respectively. The cells also deposited extracellular matrix proteins such as laminin and collagen within the grooves parallel to the groove direction. These CCFs also have the unique ability to move fluids instantaneously by capillary action, thus, have the potential to transport oxygen and nutrients deep within the scaffolds. Such CCF matrices would be useful for creating highly organized tissues such as tendon, ligament, nerve, and cardiac muscle.
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PMID:Novel capillary channel fiber scaffolds for guided tissue engineering. 1670 41

Once damaged, cardiac muscle has little intrinsic repair capability due to the poor regeneration potential of remaining cardiomyocytes. One method of overcoming this issue is to deliver functional cells to the injured myocardium to promote repair. To address this limitation we sought to test the hypothesis that electroactive carbon nanotubes (CNT) could be employed to direct mesenchymal stem cell (MSC) differentiation towards a cardiomyocyte lineage. Using a two-pronged approach, MSCs exposed to medium containing CNT and MSCs seeded on CNT based polylactic acid scaffolds were electrically stimulated in an electrophysiological bioreactor. After electrical stimulation the cells reoriented perpendicular to the direction of the current and adopted an elongated morphology. Using qPCR, an upregulation in a range of cardiac markers was detected, the greatest of which was observed for cardiac myosin heavy chain (CMHC), where a 40-fold increase was observed for the electrically stimulated cells after 14 days, and a 12-fold increase was observed for the electrically stimulated cells seeded on the PLA scaffolds after 10 days. Differentiation towards a cardioprogenitor cell was more evident from the western blot analysis, where upregulation of Nkx2.5, GATA-4, cardiac troponin t (CTT) and connexin43 (C43) was seen to occur. This was echoed in immunofluorescent staining, where increased levels of CTT, CMHC and C43 protein expression were observed after electrical stimulation for both cells and cell-seeded scaffolds. More interestingly, there was evidence of increased cross talk between the cells as shown by the pattern of C43 staining after electrical stimulation. These results establish a paradigm for nanoscale biomimetic cues that can be readily translated to other electroactive tissue repair applications.
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PMID:The electrical stimulation of carbon nanotubes to provide a cardiomimetic cue to MSCs. 2268 74