Fibronectin is an important large adhesive glycoprotein of the extracellular matrix, which is alternatively spliced in three regions, designated EIIIA, EIIIB and IIIcs respectively. IIIcs contains two binding domains for a variety of cell surface and extracellular ligands. Through this multiplicity of adhesive activities, IIIcs can fulfill key roles in a broad spectrum of physiological processes, such as cell spreading and migration, differentiation and embryogenesis, wound healing, malignant transformation and metastasis, etc. Here, we will discuss the structure, biological property, and function of IIIcs splicing variants and its forensic applications.
Alternative Splicing ; Animals ; Cattle ; Fibronectins/physiology* ; Forensic Medicine ; Humans ; Rats ; Wound Healing/physiology*

Irisin is a circulating myokine induced by exercise, which is a cleaved version of fibronectin type III domain containing protein 5 (FNDC5). It can promote the browning of white fat tissue, increase energy consumption, and decrease weight. Irisin plays an important role in the regulation of various diseases, such as diabetes and coronary heart disease. Different types of exercise have different effects on irisin level in blood circulation, and moderate exercise can reduce cardiovascular symptoms. In this paper, the cardiovascular protective effect of irisin and its research progress in the field of exercise are reviewed, hoping to provide a new target for the prevention and treatment of cardiovascular diseases.
Cardiovascular Diseases ; prevention & control ; Diabetes Mellitus ; Exercise ; Fibronectins ; physiology ; Humans ; Muscle, Skeletal ; Sports Medicine

Alternative Splicing ; Fibronectins/genetics* ; Forensic Medicine ; Humans ; Protein Conformation ; Protein Isoforms/genetics* ; Wound Healing/physiology*

PURPOSE: This study aimed to evaluate the effects of fibronectin and oxysterol immobilized on machined-surface dental implants for the enhancement of cell attachment and osteogenic differentiation, on peri-implant bone healing in the early healing phase using an experimental model in dogs. METHODS: Five types of dental implants were installed at a healed alveolar ridge in five dogs: a machined-surface implant (MI), apatite-coated MI (AMI), fibronectin-loaded AMI (FAMI), oxysterol-loaded AMI (OAMI), and sand-blasted, large-grit, acid-etched surface implant (SLAI). A randomly selected unilateral ridge was observed for 2 weeks, and the contralateral ridge for a 4-week period. Histologic and histometric analyses were performed for the bone-to-implant contact proportion (BIC) and bone density around the dental implant surface. RESULTS: Different bone healing patterns were observed according to the type of implant surface 2 weeks after installation; newly formed bone continuously lined the entire surfaces in specimens of the FAMI and SLAI groups, whereas bony trabecula from adjacent bone tissue appeared with minimal new bone lining onto the surface in the MI, AMI, and OAMI groups. Histometric results revealed a significant reduction in the BIC in MI, AMI, and OAMI compared to SLAI, but FAMI demonstrated a comparable BIC with SLAI. Although both the BIC and bone density increased from a 2- to 4-week healing period, bone density showed no significant difference among any of the experimental and control groups. CONCLUSIONS: A fibronectin-coated implant surface designed for cell adhesion could increase contact osteogenesis in the early bone healing phase, but an oxysterol-coated implant surface designed for osteoinductivity could not modify early bone healing around implants in normal bone physiology.
Alveolar Process ; Animals ; Bone and Bones ; Bone Density ; Cell Adhesion ; Dental Implants ; Dogs* ; Fibronectins ; Models, Theoretical ; Osteogenesis ; Physiology ; Surface Properties ; Titanium

OBJECTIVETo observe the expression of laminin and fibronectin in alkali-burned corneas in rats.

METHODSA total of 18 normal Wistar rats were randomly divided into 6 groups (n = 3 in each group). For each rat, one eye was injured by alkali burn, the other one was taken as the normal control. Then all the corneas were surgically removed and the expression of laminin and fibronectin was observed with immunohistochemistry respectively at 7 hours, 1 day, 3 days, 7 days, 14 days and 28 days after alkali burn.

RESULTSCompared with that of the normal controls, the expression of laminin and fibronectin of the burned eyes was dramatically higher at 7 hours, reached peak at 14 days and decreased to the normal level at 28 days after alkali burn.

CONCLUSIONSIn the process of wound healing after alkali burn, the expression of laminin and fibronectin increases dramatically, which suggests that laminin and fibronectin may participate in the process of corneal wound healing.

Animals ; Burns, Chemical ; metabolism ; Corneal Injuries ; Eye Burns ; metabolism ; Fibronectins ; metabolism ; Immunohistochemistry ; Laminin ; metabolism ; Rats ; Rats, Wistar ; Wound Healing ; physiology

OBJECTIVES: Long-term elevated blood pressure may lead to kidney damage, yet the pathogenesis of hypertensive kidney damage is still unclear. This study aims to explore the role and significance of leucine-rich alpha-2-glycoprotein-1 (LRG-1) in hypertensive renal damage through detecting the levels of LRG-1 in the serum and kidney of mice with hypertensive renal damage and its relationship with related indexes. METHODS: C57BL/6 mice were used in this study and randomly divided into a control group, an angiotensin II (Ang II) group, and an Ang II+irbesartan group. The control group was gavaged with physiological saline. The Ang II group was pumped subcutaneously at a rate of 1.5 mg/(kg·d) for 28 days to establish the hypertensive renal damage model in mice, and then gavaged with equivalent physiological saline. The Ang II+irbesartan group used the same method to establish the hypertensive renal damage model, and then was gavaged with irbesartan. Immunohistochemistry and Western blotting were used to detect the expression of LRG-1 and fibrosis-related indicators (collagen I and fibronectin) in renal tissues. ELISA was used to evaluate the level of serum LRG-1 and inflammatory cytokines in mice. The urinary protein-creatinine ratio and renal function were determined, and correlation analysis was conducted. RESULTS: Compared with the control group, the levels of serum LRG-1, the expression of LRG-1 protein, collagen I, and fibronectin in kidney in the Ang II group were increased (all P<0.01). After treating with irbesartan, renal damage of hypertensive mice was alleviated, while the levels of LRG-1 in serum and kidney were decreased, and the expression of collagen I and fibronectin was down-regulated (all P<0.01). Correlation analysis showed that the level of serum LRG-1 was positively correlated with urinary protein-creatinine ratio, blood urea nitrogen, and blood creatinine level in hypertensive kidney damage mice. Serum level of LRG-1 was also positively correlated with serum inflammatory factors including TNF-α, IL-1β, and IL-6. CONCLUSIONS Hypertensive renal damage mice display elevated expression of LRG-1 in serum and kidney, and irbesartan can reduce the expression of LRG-1 while alleviating renal damage. The level of serum LRG-1 is positively correlated with the degree of hypertensive renal damage, suggesting that it may participate in the occurrence and development of hypertensive renal damage.
Animals ; Mice ; Mice, Inbred C57BL ; Fibronectins ; Irbesartan ; Creatinine ; Kidney/physiology* ; Hypertension/complications* ; Angiotensin II ; Collagen Type I

OBJECTIVE: In order to supply an effective reference of early injury time estimation and explore the time limit of detection of EDA\EDB mRNA in human skin samples, the expression of alternative splicing segment of fibronectin--EDA\EDB in incised wound of human skin were studied. METHODS: Using in situ hybridization with DIG-labeled anti-sense RNA probe, the expression of FN EDA\EDB domain was detected in human skin incised wound at the early stage of injury (from 30 min to 3 h). RESULTS: The positive expression rates of FN-EDA\EDB immediately after injury and area far away from wound were same as the control group. The expression of FN-EDA\EDB in human skin incised wound showed a gradually increased tendency in early injury time (within 3 h). The positive expression cells were mainly distributed in basement cells of epidermis and the expression of EDA is much higher than EDB. It's difficult to detect EDA\EDB mRNA when the samples were deposited in air for 4 hour. CONCLUSION FN-EDA\EDB may be used as a sensitive mark for the estimation of early injury time. The in-situ hybridization technique is not applicable in the application.
Fibronectins/genetics* ; Forensic Medicine ; Humans ; In Situ Hybridization ; Protein Isoforms/genetics* ; RNA, Messenger/genetics* ; Skin/metabolism* ; Time Factors ; Wound Healing/physiology*

OBJECTIVETo study the expression and location of early growth response gene-1 (Egr-1), transforming growth factor-beta(1) (TGF-beta(1)), fibronectin (FN) in silicotic rat and to discuss the role of Egr-1 in the development of silicosis.

METHODSSilicotic animal model of rat was established, and the expressions of Egr-1, TGF-beta(1), FN in various lung cells of silicotic rat were analysed by using immunohistochemical technique (SP) and the image analysis.

RESULTSThe expressions of Egr-1 in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell in lung silicotic tissue (gray values: 118.58 +/- 5.65 - 168.52 +/- 5.67) were higher than those of controls (gray values: 166.23 +/- 5.23 - 188.12 +/- 8.35) during 1 - 28 days, and the expression was mainly in nucleus; the expressions of TGF-beta(1) in these cells (gray values: 123.49 +/- 5.65 - 170.24 +/- 3.56) were also higher than those of controls (166.53 +/- 6.25 - 198.56 +/- 4.53), and the expression was mainly in cytoplasm. The expressions of FN in bronchial epithelial cell, pulmonary macrophage and alveolar epithelial cell (gray values: 150.32 +/- 6.54 - 201.54 +/- 7.38) were lower, while those in interstitial cell (gray values: 121.43 +/- 5.65 - 167.55 +/- 6.35) were higher than those of controls. The changes of TGF-beta(1) and Egr-1 expression level in bronchial epithelial cell, pulmonary macrophage, alveolar epithelium cell and interstitial cell were synchronous during the experiment (1 - 28 days). Both of them were correlated with each other (r = 0.61, P < 0.01), while the expression of FN was not correlated with Egr-1, but correlated to TGF-beta(1) in interstitial cell (r = 0.46, P < 0.01).

CONCLUSIONSilicon dioxide could up-regulate the expression of nuclear transcription factor Egr-1 in several kinds of cell in lung. The activated Egr-1 may coordinate the expression of TGF-beta(1) and FN to regulate the development of silicosis.

Animals ; DNA-Binding Proteins ; analysis ; physiology ; Disease Models, Animal ; Early Growth Response Protein 1 ; Fibronectins ; analysis ; physiology ; Immediate-Early Proteins ; analysis ; physiology ; Immunohistochemistry ; Lung ; chemistry ; physiopathology ; Rats ; Silicosis ; etiology ; metabolism ; Transcription Factors ; analysis ; physiology ; Transforming Growth Factor beta ; analysis ; physiology

Laminins, a subset of glycoproteins, are main components of the basement membrane along with fibronectin, type IV collagen, and heparan sulfate proteoglycan and influence the biologic features, such as growth and polarization, of all tissues attached on the basement membrane. Although evidence has been suggested that laminins are involved in the process of hair follicle formation in mammalian skin tissues, the significance of laminin on the physiology of hair follicles remains to be fully understood. In this study, we assessed whether the distribution of laminin is associated with the growth of hair follicles and whether all-trans retinoic acid (RA), a stimulus of hair follicle growth, affects the expression profile of laminins. To observe the distribution of laminin varied depending on the developmental stages, fetuses(at day 20 of gestation) and pups(at day 1 and 3 after birth) of Sprague- Dawley rats were used. To examine the effect of RA, 5 days-old pups were administered with RA and their skin tissues were removed post mortem 2, 4, or 7 days later. Skin specimens were sectioned and observed using the immunohistochemical staining, immunogold staining for electron microscopy, and in situ RT-PCR assays. In fetuses at day 20 of gestation and 1 and 3-days-old pups, the distribution of laminin within hair follicles was restricted in the cytoplasm of fibroblasts located in hair papilla and dermal root sheath, basement membrane, and glassy membrane. Following RA treatment for 2 and 4 days, laminin expression was increased in the basement membrane, glassy membrane, outer root sheath, and dermal root sheath in hair follicles. Following RA treatment for 2 and 4 days, the level of laminin was increased in fibroblasts and matrix cells present in hair follicles, as shown in immunogold staining. The expression of laminin at day 7 post administration with RA was decreased at the level comparable with that of untreated controls. In in situ RT-PCR assays, matrix cells in hair follicles exhibited an increase in the levels of laminin alpha1 and beta1 transcripts following RA administration. Thus, these results suggest that matrix cells play a role in the growth of hair by enhancing laminin gene expression and all-trans retinoic acid promotes this induction.
Animals ; Basement Membrane ; Collagen Type IV ; Cytoplasm ; Fetus ; Fibroblasts ; Fibronectins ; Gene Expression ; Glycoproteins ; Hair Follicle* ; Hair* ; Heparan Sulfate Proteoglycans ; Laminin* ; Membranes ; Microscopy, Electron ; Physiology ; Pregnancy ; Rats* ; Skin ; Tretinoin*

BACKGROUNDPrevious researches have indicated that glioma invasion may occur within a tumor-host microecology, and that fibronectin may be involved in glioma invasion as an important component of the extracellular matrix. However, how the interaction between tumor cells and vascular endothelial cells affects glioma invasion is poorly understood. The aim of this study was to investigate the effects of the interaction between tumor cells and vascular endothelial cells on glioma invasion, and the relationship of this interaction to fibronectin.

METHODSThe localization of fibronectin in different brain astrocytoma tissues was determined by immunohistochemistry. Then, vascular endothelial cells and glioma cells were co-cultured in a Transwell co-culturing system. Fibronectin expression was detected by reverse transcriptase-polymerase chain reaction, immunocytochemistry, and enzyme-linked immunosorbent assay. Additionally, the influence of the interaction between tumor cells and vascular endothelial cells on glioma cell invasion was determined by an in vitro rapid invasion test.

RESULTSIn brain astrocytoma tissues, fibronectin was present on the endothelial cells, in the extracellular matrix. Fibronectin expression was greater in higher grade tumors than in lower grade tumors. The interaction of glioma cells and vascular endothelial cells in vitro induced fibronectin release from vascular endothelial cells, which in turn stimulated glioma cell migration. This effect was inhibited by fibronectin blocking antibody.

CONCLUSIONGlioma cells may induce vascular epithelial cells to express fibronectin, and in turn fibronectin could promote glioma cell invasion.

Astrocytoma ; metabolism ; Brain Neoplasms ; metabolism ; Cell Movement ; physiology ; Cells, Cultured ; Coculture Techniques ; Enzyme-Linked Immunosorbent Assay ; Fibronectins ; metabolism ; Glioma ; metabolism ; Humans ; Immunohistochemistry ; Reverse Transcriptase Polymerase Chain Reaction