Disease relevance of Stress, Mechanical

• We report activation of Cdk7 and -9 in hypertrophy triggered by signaling proteins (Galphaq, calcineurin) or chronic mechanical stress [1].
• Enhancement of osteoclastic bone resorption and suppression of osteoblastic bone formation in response to reduced mechanical stress do not occur in the absence of osteopontin [2].
• The interleukin-6 cytokines, acting via gp130 receptor pathways, play a pivotal role in the reduction of cardiac injury induced by mechanical stress or ischemia and in promoting subsequent adaptive remodeling of the heart [3].
• CONCLUSION: MEA may exert therapeutic effects on cardiac disorders due to ventricular fibrosis through suppression of PLD activity and modulation of the fibrosis pathway even without relief from mechanical stress [4].
• Thus it is suggested that local mechanical stress accelerates beta 2m amyloidosis [5].

High impact information on Stress, Mechanical

• Stimulation with adenosine 5'-triphosphate (ATP), uridine 5'-triphosphate (UTP), acetylcholine, endothelin, A23187 and mechanical stress releases Up(4)A from endothelium, suggesting that Up(4)A contributes to vascular autoregulation [6].
• Thus, melusin prevents cardiac dilation during chronic pressure overload by specifically sensing mechanical stress [7].
• There is increasing evidence that mechanotransduction processes in response to mechanical stresses share many common features with processes in cell adhesion, such as an increase in tyrosine phosphorylation of proteins in the focal adhesion sites [8].
• Thus, mechanical stress activates AT1 receptor independently of angiotensin II, and this activation can be inhibited by an inverse agonist of the AT1 receptor [9].
• Mechanical stress activates angiotensin II type 1 receptor without the involvement of angiotensin II [9].

Chemical compound and disease context of Stress, Mechanical

• The 10% and 20% dietary xylitol supplementation significantly prevented the type I diabetes-induced decrease in the mechanical stress resistance of the tibia in the three-point bending test, the shear stress of the femur in the torsion test, and the stress resistance of the femoral neck in the loading test [10].
• Various potential contributors to the inflammatory response in the vessel wall include atherogenic lipids, mechanical stress and injury, hypertension and angiotensin II, cigarette smoking, immune response to neoantigens, and chronic infections with viruses and or bacteria (Table 1) [11].
• We propose that, in addition to mechanical stress, the rise of estrogen toward the end of pregnancy contributes to pregnancy-related heart hypertrophy by increased c-Src activity and that the rise of estrogen is one factor that down regulates cardiac Kv4.3 gene expression providing a molecular correlate for a longer QT interval in pregnancy [12].
• In addition, it is conceivable that, under certain pathophysiological conditions (e.g., ischemia or excessive mechanical stress), the sensitivity of the channels could be altered in such a way that the conductance opens even in the presence of physiological Ca(2+), Mg(2+), and insulin [13].
• These findings suggest that aging in both HGF and HPLF may be an important factor in the severity of periodontal disease through higher production of inflammatory mediators in response to both LPS and mechanical stress [14].

Biological context of Stress, Mechanical

• The intermediate filament vimentin might play a key role in vascular resistance to mechanical stress [15].
• The crystal structure of the zymogen catalytic domain of complement protease C1r reveals that a disruptive mechanical stress is required to trigger activation of the C1 complex [16].
• LeMPK3 gene expression was also induced very rapidly by mechanical stress and wounding much earlier than upon pathogen infection, but not in response to the defense-related plant hormones ethylene and jasmonic acid [17].
• Prostaglandin up-regulation is associated with an induction of PGHS-2 enzyme mRNA, which may subsequently provide a means for amplifying the cellular response to mechanical stress [18].
• These studies demonstrate that N-cadherin-mediated adhesion is critical for maintaining cell-cell interactions in tissues undergoing active cellular rearrangements and increased mechanical stress associated with morphogenesis [19].

Anatomical context of Stress, Mechanical

• Thus, OPN is a molecule required for the bone loss induced by mechanical stress that regulates the functions of osteoblasts and osteoclasts [2].
• Although mammalian cardiac muscle cells express bFGF, it is not known whether it plays a role in mediating cardiac adaptation to increased load, nor how release of the cytosolic 18-kD isoform of bFGF would be regulated in response to increased mechanical stress [20].
• Regulation of extracellular matrix by mechanical stress in rat glomerular mesangial cells [21].
• Tensegrity predicts that cells are hard-wired to respond immediately to mechanical stresses transmitted over cell surface receptors that physically couple the cytoskeleton to extracellular matrix (e.g. integrins) or to other cells (cadherins, selectins, CAMs) [22].
• Thickening of actin stress fibers reflects a cellular adaptation to mechanical stress; this cytoskeletal reinforcement coincides with zyxin mobilization and is abrogated in zyxin-null cells [23].

Associations of Stress, Mechanical with chemical compounds

• Here we show that mechanical stresses applied to the cell surface alter the cyclic AMP signalling cascade and downstream gene transcription by modulating local release of signals generated by activated integrin receptors in a G-protein-dependent manner, whereas distortion of integrins in the absence of receptor occupancy has no effect [24].
• Here we show that the AT1 receptor can be activated by mechanical stress through an angiotensin-II-independent mechanism [9].
• The structure reveals unusual features in the SP domain and provides strong support for the hypothesis that C1r activation in C1 is triggered by a mechanical stress caused by target recognition that disrupts the CCP1-SP interfaces and allows formation of transient states involving important conformational changes [16].
• Gene-specific probes were constructed to examine the expression of transcripts encoding the two ACC synthase isoforms under two conditions of enhanced ethylene formation--namely, during fruit ripening and in response to mechanical stress (wounding) [25].
• Interestingly, these non-CRAC channels are selectively activated by mechanical stress, although the mechanism overlaps with BCR-activated pathways, suggesting that they may operate in concert to produce functionally diverse Ca(2+) signals [26].

Gene context of Stress, Mechanical

• The tissue-specific expression of TCH3 suggests that expression may be regulated not only by externally applied mechanical stimuli but also by mechanical stresses generated during development [27].
• Lack of plakoglobin affects the number and structure of desmosomes, resulting in visible defects when cells are subjected to increasing mechanical stress, e.g. when embryonic blood starts circulating or during skin differentiation [28].
• These data link alterations in the microtubule and actin cytoskeleton to the expression of CTGF and provide a molecular basis for the observation that CTGF is up-regulated in cells exposed to mechanical stress [29].
• Suramin, a growth factor receptor antagonist, completely abolished ERK activation, significantly blocked MKP-1 expression, but not JNK/SAPK and p38 MAPK activation, in response to mechanical stress [30].
• Herein, we provide evidence that VSMC responses to mechanical stress also include induction of MAPK phosphatase-1 (MKP-1), which may serve as a negative regulator of MAPK signaling pathways [30].

Analytical, diagnostic and therapeutic context of Stress, Mechanical

• FHL2-deficient mice are viable and maintain normal cardiac function both before and after acute mechanical stress induced by aortic constriction [31].
• Local increases in the intracellular Ca2+ concentration ([Ca2+]i) in several regions within the bovine lens epithelial cell during application of mechanical stress were clearly visualized in the presence of lysophosphatidic acid (LPA), a bioactive lysophospholipid, using real-time confocal microscopy [32].
• To examine the effect of mechanical stress on the expression of PGI2 synthase, cells were subjected to uniaxial cyclic stretch (0.5 Hz, 20% stretch), and PGI2 synthase mRNA expression was assessed by quantitative RT-PCR [33].
• First, handmade bovine pericardial bioprostheses, subjected to chemical treatment with chloroform/ methanol and glutaraldehyde or treated with glutaraldehyde alone for use as controls, were subjected to mechanical stress in a heart valve, accelerated wear tester (100 x 10(6) consecutive cycles) [34].
• Here, we analyzed the effects of mechanical stress (free and forced mobilization vs. immobilization and denervation separately and in combination) on the expression of alpha7 integrin and merosin in regenerating myofibres using quantitative in situ hybridization and immunohistochemistry [35].

References