Cell adhesion is a basic and very important tissue in the field of tissue engineering. Fibronectin and integrins are the most important elements to cell adhesion. Some surface receptors of fibroblast can also conjugate with type I collagen in extracellular matrix (ECM) directly. Laminin receptors on the surface of fibroblast bound to laminin also play a role in cell adhesion. In this paper are reviewed a number of related articles. The structures and function of fibronectin and integrins are discussed in detail; the tendon cell's adhesion structures are also discussed. Yet, there was scarcely any paper on the effects which the preservation of tissue engineered products may have on cells' adhesion fo ECM. Therefore, researching on cell adhesion and finding a way of preservation that has no or very little adverse effect on cell adhesion is an important topic. Results from expected advanced researches on cell adhesion may probably find promising applications in the field of tissue engineering.
Cell Adhesion ; Extracellular Matrix ; metabolism ; Fibroblasts ; cytology ; Fibronectins ; metabolism ; Humans ; Integrins ; metabolism ; Laminin ; metabolism ; Tendons ; metabolism ; Tissue Engineering

Osteoarthritis (OA) is a kind of degenerative disease characterized by hyperosteogeny at the joint margins and articular cartilage degeneration. Mechanical stress can regulate the multiple functions of cells. The integrin as one of the mechanoreceptors on the surface of cells, mainly mediated adhesion between cells and extracellular matrix, which plays an important role in the mechanical signal transmission to regulate the physiological functions of cell. Therefore, it is very important to select proper mechanical stimulation (such as naprapathy) in the early and middle stage of osteoarthritis, which regulate the expression of integrins to affect the function of chondrocytes, repair the damaged chondrocyte and delay the articular cartilage degeneration.
Animals ; Biomechanical Phenomena ; Chondrocytes ; cytology ; metabolism ; pathology ; Gene Expression Regulation ; Humans ; Integrins ; metabolism ; Mechanical Phenomena ; Protein Subunits ; metabolism

Distant metastasis is the main cause of cancer death. Tetraspanins (transmembrane 4 superfamily, TM4SF) is capable of forming transmembrane complexes with integrin family participating in cell adhesion, migration and tumor metastasis. This review elucidates the structure of tetraspanins and its function in regulating metastasis as form of multimolecular transmembrane complexes with integrin.
Cell Adhesion ; Humans ; Integrins ; chemistry ; metabolism ; physiology ; Membrane Proteins ; chemistry ; metabolism ; physiology ; Neoplasm Metastasis ; Neoplasms ; metabolism ; pathology ; Tetraspanins

OBJECTIVETo investigate the role of integrin α4β7 in the development of ulcerative colitis (UC) in rats.

METHODSSixty Sprague-Dawley rats were randomly divided into the control group (acetone enema), the model group (2,4-dinitrochlorobenzene, DNCB enema), and the α4 intervention group. Colonic mucosa of different groups was observed and compared in terms of pathology and cytokine changes(IL-2 and IL-6) using ELISA. Semi-quantitative RT-PCR was used to detect the colon α4β7 expression. Integrin α4β7(+) lymphocytes in the portal vein of rats were determined by flow cytometry.

RESULTSThe expression of α4 mRNA was 0.68±0.24 in the model group and 0.58±0.37 in the intervention group, and the expression of β7 mRNA was 0.84±0.37 in the model group and 0.65±0.30 in the intervention group, which were all significantly higher as compared to those in the control group(0.15±0.13 for α4 and 0.24±0.62 for β7, P<0.01). The proportions of integrin α4β7 positive lymphocytes in the portal vein in the model group and intervention group were significantly higher than that in the control group [(76.7±8.2)% and (68.2±7.6)% vs. (14.7±6.7)%, P<0.01]. The expression of IL-2 and IL-6 and the result of macroscopic and microscopic scores in the intervention group were lower than those in the model group(P<0.05).

CONCLUSIONSHigh expression of α4β7 may play an important role in experimental colon mucosa inflammation in rats with ulcerative colitis. The blockade of integrin α4β7 may be a potential target to reduce colonic mucosa inflammation.

Animals ; Colitis, Ulcerative ; metabolism ; pathology ; Colon ; metabolism ; pathology ; Disease Models, Animal ; Female ; Integrins ; metabolism ; physiology ; Interleukin-2 ; metabolism ; Interleukin-6 ; metabolism ; Intestinal Mucosa ; pathology ; Rats

Kindlin-2 belongs to a subfamily of FERM domain containing proteins, which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion. Compared to conventional FERM domains, kindlin-2 FERM contains an inserted pleckstrin homology (PH) domain that specifically binds to phosphatidylinositol (3,4,5) trisphosphate (PIP3) and regulates the kindlin-2 function. We have determined the crystal structure of kindlin-2 PH domain at 1.9 Å resolution, which reveals a conserved PH domain fold with a highly charged and open binding pocket for PIP3 head group. Structural comparison with a previously reported solution structure of kindlin-2 PH domain bound to PIP3 head group reveals that upon PIP3 insertion, there is a significant conformational change of both the highly positively charged loop at the entry of the PIP3 binding pocket and the entire β barrel of the PH domain. We propose that such "induced-fit" type change is crucial for the tight binding of PIP3 to anchor kindlin-2 onto the membrane surface, thereby promoting its binding to integrins. Our results provide important structural insight into kindlin-2-mediated membrane anchoring and integrin activation.
Animals ; Crystallography, X-Ray ; Cytoskeletal Proteins ; chemistry ; metabolism ; Humans ; Integrins ; metabolism ; Membrane Proteins ; chemistry ; metabolism ; Mice ; Models, Molecular ; Muscle Proteins ; chemistry ; metabolism ; Neoplasm Proteins ; chemistry ; metabolism ; Protein Conformation

The process of human embryo implantation is mediated not only by evolutionarily conserved mechanisms, but also by a mechanism unique to humans. Evidence suggests that the cell adhesion molecules, L-selectin and trophinin, play a unique role in human embryo implantation. Here, we describe the dual roles of mucin carbohydrate ligand for L-selectin and trophinin protein and of the trophinin-associated proteins bystin and tastin. We then describe trophinin-mediated signal transduction in trophectoderm cells and endometrial epithelial cells. This review also covers cadherin and integrin in human embryo implantation.
Cadherins ; physiology ; Cell Adhesion Molecules ; physiology ; Embryo Implantation ; Epithelial Cells ; metabolism ; Humans ; Integrins ; physiology ; L-Selectin ; physiology ; Signal Transduction

Integrins are a family of transmembrane receptors that connect the extracellular matrix and actin skeleton, which mediate cell adhesion, migration, signal transduction, and gene transcription. As a bi-directional signaling molecule, integrins can modulate many aspects of tumorigenesis, including tumor growth, invasion, angiogenesis, metastasis, and therapeutic resistance. Therefore, integrins have a great potential as antitumor therapeutic targets. In this review, we summarize the recent reports of integrins in human hepatocellular carcinoma (HCC), focusing on the abnormal expression, activation, and signaling of integrins in cancer cells as well as their roles in other cells in the tumor microenvironment. We also discuss the regulation and functions of integrins in hepatitis B virus-related HCC. Finally, we update the clinical and preclinical studies of integrin-related drugs in the treatment of HCC.
Humans ; Integrins/metabolism* ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Cell Adhesion ; Carcinogenesis ; Cell Transformation, Neoplastic ; Tumor Microenvironment

OBJECTIVETo study the mechanism of integrin in hypertrophic scar.

METHODSFibroblasts from 10 samples of human hypertrophic scars was cultured, FQ-PCR assay was applied to detect mRNA expression of alpha-SMA in hypertrophic scar fibroblasts after integrin and FAK antibody blocking.

RESULTSmRNA of alpha-SMA in fibroblasts expressed obviously lower after integrin and FAK antibody blocking than that of control groups ( P < 0.05).

CONCLUSIONThrough accelerating the synthesis of alpha-SMA, integrin and FAK play an important role in contracture of hypertrophic scar.

Actins ; biosynthesis ; Adult ; Cells, Cultured ; Cicatrix, Hypertrophic ; metabolism ; pathology ; Contracture ; metabolism ; pathology ; Fibroblasts ; metabolism ; Focal Adhesion Kinase 1 ; biosynthesis ; Humans ; Integrins ; biosynthesis ; RNA, Messenger ; metabolism ; Young Adult

Normal articular cartilage is composed of chondrocytes embedded within an extracellular matrix (ECM). The patterns of integrin expression determine the adhesive properties of cells by modulating interactions with specific ECMs. Our hypothesis is that chondrocyte integrin expression changes in response to changes in their microenvironment. Porcine articular chondrocytes were encapsulated in alginate beads with several ECMs (collagen type I, collagen type II and fibronectin) for 7 days, subjected to RT-PCR, western blot analysis and immunofluorescence staining. It was found that chondrocytes in different ECMs showed different patterns of integrin expression. Integrin alpha5 and beta1 were strongly expressed in all groups, but integrin alpha1 was strongly expressed only in collagen type I and fibronectin conjugated alginate beads, and integrin alpha2 was strongly expressed only in collagen type II conjugated alginate beads. These findings suggest that the addition of different ECMs to chondrocytes can modulate the patterns and levels of integrin expression possibly through a feedback mechanism. These finding suggest that the modulation of ECM interactions may play a critical role in the pathogenesis of osteoarthritis.
Animals ; Cartilage, Articular/cytology/*metabolism ; Chondrocytes/*metabolism ; Extracellular Matrix/*physiology ; Fluorescent Antibody Technique ; Integrins/genetics/*metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Support, Non-U.S. Gov't ; Swine

OBJECTIVETo investigate the effect of integrin α9β1 on corneal angiogenesis and the expression of vascular endothelial growth factor A (VEGF-A) in rats after corneal suture.

METHODSThirty-nine SD rats were randomly divided into normal control group, corneal suture model group, α9β1 group, and α9β1 suppression group, and in the latter 3 groups, the rats received topical administration of levofloxacin, levofloxacin + α9β1, and levofloxacin+ anti-α9β1 monoclonal antibody (Y9A2) twice daily after corneal suture, respectively. At 3, 5, 7, 14 days after the surgery, 3 rats were randomly selected from each group to observe corneal neovascularization (CNV) under slit lamp. RT-PCR and Western blotting were used to detect the expressions of VEGF-A.

RESULTSCNV was not observed in normal cornea. Neovascularization occurred in the corneal limbus in the 3 corneal suture groups, and the leak neovascularization count (CNVC), which occurred on the 7th postoperative day, was significantly increased after α9β1 treatment compared with that in the model group (4.57∓0.31 vs 3.21∓0.19, P<0.05) but markedly decreased after α9β1 suppression (2.03∓0.26, P<0.05). VEGF-A was expressed at a low level in normal cornea, and increased significantly in the model group, reaching the peak level on 7th day (P<0.05); corneal VEGF-A expression was further enhanced by α9β1 treatment (P<0.05) while significantly lowered by α9β1 suppression (P<0.05).

CONCLUSIONIntegrin α9β1 can promote CNV by up-regulating VEGF-A expression and α9β1 suppression produces the opposite effect after corneal suture in rats.

Animals ; Cornea ; drug effects ; metabolism ; Corneal Neovascularization ; metabolism ; Female ; Integrins ; antagonists & inhibitors ; Rats ; Rats, Sprague-Dawley ; Sutures ; Vascular Endothelial Growth Factor A ; metabolism