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Research Containing: Mechanotransduction

Properties of mechano-transduction via simulated microgravity and its effects on intracellular trafficking of VEGFR's

by on 9 June 2015in Biology & Biotechnology No comment

This study emphasizes the dynamical properties of mechanical loading via simulated microgravity, its effect on acute myeloid leukemia proliferation and hematopoietic stem cell (HSPC) growth and its implications in the area of tissue regeneration. Data presented illustrates that mechanical transduction changes the expression of humoral factors by facilitating paracrine/autocrine signalling, therefore modulating intracellular trafficking of tyrosine kinase receptors. Understanding mechano-transduction in the context of cell and tissue morphogenesis is the major focus of this study. The effects of external physiological stresses, such as blood flow, on several cellular subtypes seem to produce very intricate cellular responses. It is well accepted that mechanical loading plays an intrinsic and extrinsic influence on cell survival. This study shows how microgravity effects hematopoietic stem cells, and human leukemic cell proliferation and expression of its receptors that control cell survival, such as the tyrosine kinase vascular endothelial growth factor receptor-1, receptor-2 and receptor-3.

Related URLs:
http://ovidsp.ovid.com/ovidweb.cgi?T=JS&CSC=Y&NEWS=N&PAGE=fulltext&D=emed10&AN=2012656922
http://sfxhosted.exlibrisgroup.com/mayo?sid=OVID:embase&id=pmid:&id=doi:&issn=1949-2553&isbn=&volume=3&issue=4&spage=426&pages=426-434&date=2012&title=Oncotarget&atitle=Properties+of+mechano-transduction+via+simulated+microgravity+and+its+effects+on+intracellular+trafficking+of+VEGFR%27s&aulast=Puca&pid=%3Cauthor%3EPuca+A.%3C%2Fauthor%3E&%3CAN%3E2012656922%3C%2FAN%3E

Microbial responses to microgravity and other low-shear environments

by on 9 June 2015in Biology & Biotechnology No comment

Microbial adaptation to environmental stimuli is essential for survival. While several of these stimuli have been studied in detail, recent studies have demonstrated an important role for a novel environmental parameter in which microgravity and the low fluid shear dynamics associated with microgravity globally regulate microbial gene expression, physiology, and pathogenesis. In addition to analyzing fundamental questions about microbial responses to spaceflight, these studies have demonstrated important applications for microbial responses to a ground-based, low-shear stress environment similar to that encountered during spaceflight. Moreover, the low-shear growth environment sensed by microbes during microgravity of spaceflight and during ground-based microgravity analogue culture is relevant to those encountered during their natural life cycles on Earth. While no mechanism has been clearly defined to explain how the mechanical force of fluid shear transmits intracellular signals to microbial cells at the molecular level, the fact that cross talk exists between microbial signal transduction systems holds intriguing possibilities that future studies might reveal common mechanotransduction themes between these systems and those used to sense and respond to low-shear stress and changes in gravitation forces. The study of microbial mechanotransduction may identify common conserved mechanisms used by cells to perceive changes in mechanical and/or physical forces, and it has the potential to provide valuable insight for understanding mechanosensing mechanisms in higher organisms. This review summarizes recent and future research trends aimed at understanding the dynamic effects of changes in the mechanical forces that occur in microgravity and other low-shear environments on a wide variety of important microbial parameters.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/15187188

Ex vivo expansion of hematopoietic stem cells derived from umbilical cord blood in rotating wall vessel

by on 9 June 2015in Biology & Biotechnology No comment

Expansion of umbilical cord blood mononuclear cells (UCB MNCs) was carried out in a rotating wall vessel (RWV) bioreactor and tissue culture flasks (T-flasks) in serum-containing medium supplemented with relatively low doses of purified recombinant human cytokines (5.33 ng/ml IL-3, 16 ng/ml SCF, 3.33 ng/ml G-CSF, 2.13 ng/ml GM-CSF, 7.47 ng/ml FL and 7.47 ng/ml TPO) for 8 days. The cell density, pH and osmolality of the culture medium in the two culture systems were measured every 24 It. Flow cytometric assay for CD34(+) cells was carried out at 0, 144 and 197 h and methylcellulose colony assays were performed at 0, 72, 144 and 197 It. The pH and osmolality of the medium in the two culture systems were maintained in the proper ranges for hematopoietic stem cells (HSCs) and progenitors culture. The RWV bioreactor, combined with a cell-dilution feeding protocol, was efficient to expand UCB MNCs. At the end of 200 h culture, the total cell number was multiplied by 435.5 +/- 87.6 times, and CD34(+) cells 32.7 +/- 15.6 times, and colony-forming units of granulocyte-macrophage (CFU-GM) 21.7 +/- 4.9 times. While in T-flasks, however, total cells density changed mildly, CD34(+) cells and CFU-GM decreased in number. It is demonstrated that the RWV bioreactor can provide a better environment for UCB MNCs expansion, enhance the contact between HSCs and accessory cells and make the utilization of cytokines more effective than T-flask. (c) 2006 Elsevier B.V. All rights reserved.

Related URLs:
<Go to ISI>://WOS:000239156700012

Erk 1/2 activation in enhanced osteogenesis of human mesenchymal stem cells in poly(lactic-glycolic acid) by cyclic hydrostatic pressure

by on 9 June 2015in Biology & Biotechnology No comment

The aim of this study was to identify the signal transduction pathways and mechano-transducers that play critical roles in the processes induced by changes in cyclic hydrostatic pressure and fluid shear in 3-dimensional (3D) culture systems. Mesenchymal stem cells were loaded into a polymeric scaffold and divided into three groups according to the stress treatment: static, fluid shear, and hydrostatic pressure with fluid shear. Cells were exposed daily to a hydrostatic pressure of 0.2 MPa for 1 min followed by 14 min rest with fluid flow at 30 rpm. Protein extracts were analyzed by Western blot for extracellular signal-regulated kinase 1/2 (ERK1/2). The complexes were cultured under the mechanical stimuli for 21 days with or without phospho-ERK1/2 inhibitor (U0126) and evaluated by RT-PCR, calcium contents, and immunohistochemistry. Under conditions of mechanical stimulation, the activation of ERK1/2 was sustained or increased with time. U0126 suppressed mechanical stimuli-induced expression of osteocalcin. In addition, calcium contents and the degrees of osteocalcin and osteopontin staining were decreased by this inhibitor. These results demonstrate that mechanical stimuli, particularly hydrostatic pressure with fluid shear, enhance osteogenesis in 3D culture systems via ERK1/2 activation. (c) 2006 Wiley Periodicals, Inc.

Related URLs:
<Go to ISI>://WOS:000244429600007