Protein Expression Of p-FAK Research Articles

Massage protects skeletal muscle from injury during long-term heavy-duty exercise via integrin β1 and laminin 2 channels of basement membrane

BackgroundMassage is widely used in exercise-induced skeletal muscle damage (EIMD). It has been proven that massage can improve the morphology and function of damaged skeletal muscle in multiple ways. However, whether massage can protect skeletal muscles from injury during long-term heavy-duty exercise has not yet been determined.MethodsIn this study, a rat model of overuse injury was established by eccentric running for 4 weeks, and pressing at constant pressure and frequency and massage were used as intervention methods to explore whether massage could protect skeletal muscle from injury through upregulating integrin and the basement membrane laminin.ResultsThe results showed that compared with the model group, the ultrastructure of skeletal muscle in the massage group was relatively complete and clear, and the maximum isotonic and tetanic contraction forces were significantly increased (P < 0.01). In addition, in the massage group, β1 integrin expression was significantly increased, p-FAK protein expression was decreased, and the co-localization of β1 integrin and the basement membrane laminin 2 was significantly increased (P < 0.01).ConclusionOur study shows that during long-term heavy-duty exercise, massage can enhance the cell adhesion function mediated by integrin β1 and laminin 2 to protect skeletal muscle from injury and prevent the occurrence of overuse injury.

Fak silencing impairs osteogenic differentiation of bone mesenchymal stem cells induced by uniaxial mechanical stretch

Background/purposeMechanical stretch plays a key role in promoting proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs) in distraction osteogenesis (DO). A better understanding of how the extracellular biomechanical stimulation is transferred to intracellular signal expression will benefit DO. Focal adhesion kinase (FAK) is a key factor in integrin signaling pathway. However, little is known about the effect of integrin-FAK signaling during the process of stretch induced osteogenic differentiation of BMSCs. Materials and methodsA specific short hairpin RNAs (shRNAs) lentiviral expression vector was used to silence Fak gene and a well-established in vitro uniaxial dynamic stretching device was applied to stimulate DO. Fak silencing was confirmed by fluorescence microscopy and the detection of Fak mRNA and FAK, p-FAK protein expression. Alkaline phosphatase (ALP) activity, expression of osteogenic differentiation markers - runt-related transcription factor 2 (RUNX2/Runx2) and alkaline phosphatase (Alp) together with integrin upstream signal transduction molecules integrin beta-1 (ITGB1/Itgb1) and downstream signal transduction molecules integrin-linked kinase (ILK) were detected after the stretch. ResultsThe results showed that mechanical stretch in control groups significantly induced the osteogenic differentiation of BMSCs with increased ALP activity, expression of RUNX2/Runx2 and Alp, together with upregulated ITGB1/Itgb1 and ILK, which all vanished in Fak silencing group. ConclusionSilencing of the Fak gene inhibited the osteogenic differentiation of rat BMSCs induced by in vitro mechanical stretch through integrin signaling pathway.

NGF/FAK signal pathway is implicated in angiogenesis after acute cerebral ischemia in rats

Neurogenesis in the cerebral infarction after an ischemic event is important to the rehabilitation of patients. However, the mechanism of angiogenesis around cerebral ischemia is not clear. Our study designed to test whether the nerve growth factor (NGF)-P-focal adhesion kinase (FAK) signaling pathway for associations with angiogenesis plays a key role in post-acute cerebral ischemia of rats. Firstly, we implanted the Matrigel, a carrier of basement membrane matrix, into the abdominal skin of rats to identify the relevant components of the NGF-P-FAK signaling pathway related to angiogenesis. Secondly, we used a model established by ligation of the middle cerebral artery (MCA) to observe the effect of the same signal pathway on angiogenesis in the subventricular and subgranular zones of the dentate gyrus(SVG and SGZ). The results showed that the tissue scores was significantly increased by NGF. However, the tissue scores was signifcaintly decreased by FAK inhibitor TAE226. Furthermore, CD31 and α-SMA were significantly increased by NGF and were decreased by anti-NGF and TAE226 in Matrigel. The P-FAK protein expression in Matrigel was markedly increased by NGF and decreased by TAE226. In the SVZ and SVG of cerebral ischemia, the numbers of BrdU-positive cells were significantly increased by NGF and decreased by TAE226, respectively. Our findings suggest that the therapy targeting the NGF-P-FAK signaling pathway may be an option for patients suffering from cerebral ischemia.

RLj-RGD3, a Novel Three-RGD-Motif-Containing Recombinant Protein from Lampetra japonica, Protects PC12 Cells from Injury Induced by Oxygen-Glucose Deprivation and Reperfusion.

rLj-RGD3 is a 14.5 kDa recombinant protein with 3 RGD (Arg-Gly-Asp) motifs from the salivary gland secretions of Lampetra japonica, which is a histidine-rich and arginine-rich protein. Previous reports indicated that rLj-RGD3 has typical functions of RGD-toxin protein, such as platelet aggregation suppression tumour metastasis and angiogenesis inhibition. Because histidine and arginine have cerebral ischemia-reperfusion and neuroprotective functions, we investigated whether rLj-RGD3 has such activities and studied the mechanism. The effects of rLj-RGD3 on neuroprotection and antiapoptosis were determined. The expression level of focal adhesion kinase (FAK), p-FAK, Caspase-3, and Bcl-2 after oxygen-glucose deprivation and reperfusion (OGD-R) was examined. The viability of PC12 cells incubated with rLj-RGD3 at high concentrations (16 μmol/L) increased significantly due to its ability to protect the cells from apoptosis after OGD-R-induced injury. Furthermore, rLj-RGD3 attenuated the damage due to OGD-R. Most of the PC12 cells were apoptotic after OGD-R. In contrast, the number of apoptotic PC12 cells was significantly decreased in the group treated with a high-dose of rLj-RGD3. In addition, rLj-RGD3 activated FAK and p-FAK protein. rLj-RGD3 inhibited Caspase-3 and upregulated Bcl-2 protein expression in PC12 cells after OGD-R. The study provides the first evidence for neuroprotective effects of rLj-RGD3 in ischemic injury that may be partly mediated through inhibition of Caspase-3 and upregulation of Bcl-2, FAK, and p-FAK protein expression.

Preliminary Study On Influence of Imatinib-Induced Apoptosis in Chronic Myeloid Leukemia Cells Co-Culture with Fibronectin Adhesion.

Abstract 4264The bone marrow microenvironment supports growth, differentiation and proliferation of normal hematopoietic cells and can also contribute to malignant growth. Recently,it is considered that except for the point mutant of BCR-ABL kinase contribute to imatinib-resistant therapy for patients with chronic myeloid leukemia(CML), environment-mediated drug resistance (EM-DR) is a potential factor in imatinib resistance. Our previous studies found that Integrin, focal adhesion kinase(FAK), RhoA(a small GTPase) are important adhesion molecules,and related to imatinib resistance. But how and what they crosstalk with each other is still open to debate.In order to simulated bone marrow microenvironment, we used the major components of bone marrow microenvironment- Fibronectin (Fn) co-cultured with human leukemia K562 cells.and then K562 cells were inoculated with Fn, collagen-coated plate(Co) and suspended cultures as control(mask) group,and then treated with 0.4μM,0.8μM,1.6μM,3.2μM,6.4μM imatinib for 24h,48h and 72h, detected cell apoptosis and proliferation by MTT and AnnexinV-PI assay, examined p-FAK and Rho-GTP by Wersten Blotting and Pull down-Wersten Blotting. The data showed that compared to the Co and mask groups, the cells growth inhibition and apoptosis in Fn co-culture group was significantly reduced. The protein expression of p-FAK and Rho-GTP was higher in the Fn group,and in time-dependent manner. When K562 cells in Fn group were transfected with 150nM siRNA-RhoA for 48h, there was no significant difference compared with the Co and mask groups. Furthermore, the above groups treated with anti-integrin monoclonal antibody (anti-CD29 mAb), we found that p-FAK was significant lower compared with without anti-CD29 mAb in the Fn group; but there was no significant difference of Rho-GTP compard with without anti-CD29 mAb in Fn group. These results indicate that Fn adhesion co-culture could reduce imatinib-induced cell growth inhibition and apoptosis, and this mechanism may be correlated to Rho-GTP activity,and anti-integrin monoclonal antibody could not completely block the integrin binding to Fn on K562 cells, or there was other pathway activated RhoA. The mechanism of EM-DR is complex,and which is well worth us to speculate and study. Disclosures:No relevant conflicts of interest to declare.