TGF-beta1 regulates TGF-beta1 and FGF-2 mRNA expression during fibroblast wound healing (original) (raw)
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Transforming growth factor-?1 expression in cultured corneal fibroblasts in response to injury
Journal of Cellular Biochemistry, 2000
Aims: To evaluate the expression of transforming growth factor β1 (TGF-β1) and fibroblast growth factor 2 (FGF-2) mRNA in stromal cells in response to injury in the presence of either TGF-β1 or FGF-2. It has been shown previously that heparan sulfate proteoglycans and FGF-2 are present transiently during wound repair in vivo and that an increase in TGF-β1 mRNA is detected rapidly after injury. Methods: Primary corneal fibroblasts were cultured to confluency, serum starved, and linear wound(s) were made in medium containing TGF-β1 or FGF-2. TGF-β1 and FGF-2 mRNA expression were evaluated using both northern blot analysis and in situ hybridisation. Both dose dependent and time course experiments were performed. Whole eye organ culture experiments were also carried out and growth factor expression was assessed.
Distribution of TGF-β isoforms and signaling intermediates in corneal fibrotic wound repair
Journal of Cellular Biochemistry, 2009
In this study, temporal and spatial distribution of three TGF-b isoforms and their downstream signaling pathways including pSmad2 and p38MAPK were examined during fibrotic wound repair. In normal chick corneas, TGF-b1, -2, and -3 were weakly detected in Bowman's layer (BL). In healing corneas, TGF-b1 was primarily deposited in the fibrin clot and the unwounded BL. TGF-b2 was highly expressed in healing epithelial and endothelial cells, and numerous active fibroblasts/myofibroblasts. TGF-b3 was mainly detected in the unwound region of basal epithelial cells. a-Smooth muscle actin (a-SMA) was initially appeared in the posterior region of repairing stroma at day 3, and was detected in the entire healing stroma by day 7. Notably, a-SMA was absent in the central region of healing stroma by day 14, and its staining pattern was similar to those of TGF-b2 and p38MAPK. By contrast, pSmad2 was mainly detected in the fibroblasts. In normal cornea, laminin was mainly detected in both epithelial basement membrane (BM) and Descemet's membrane (DM). By contrast to reconstitution of the BM in the wound region, the DM was not repaired although endothelial layer was regenerated, indicating that high levels of TGF-b2 were released into the posterior region of healing stroma on day 14. High levels of a-SMA staining, shown in cultured repair stromal cells from healing corneas on day 14 and in TGF-b2 treated normal stromal cells, were significantly reduced by p38MAPK inhibition. Collectively, this study suggests that TGF-b2-mediated myofibroblast transformation is mediated, at least partly, by the p38MAPK pathway in vivo.
Acta Ophthalmol Scandinavica, 2005
To study the expression of basic fibroblast growth factor (bFGF) in the early phases of corneal wound healing in the presence or absence of granulocytes. Methods: A central penetrating corneal alkali wound was inflicted to one eye in each of 14 rabbits under general anaesthesia. Subsequently, seven of the rabbits were given fucoidin i.v. for 36 hours in order to block the selectins on the vascular endothelium, thus preventing blood granulocytes from entering the tissues. Then, corneas were prepared, stained for bFGF and evaluated by light microscopy. Results: Whereas normal corneal epithelium expressed bFGF weakly, conjunctival epithelium did so strongly, particularly the goblet cells. The corneal endothelium showed medium staining, while keratocytes and vascular endothelial cells did not consistently express bFGF. After 36 hours of wound healing, a marked upregulation of bFGF expression was observed in the corneal epithelial and endothelial cells, as well as in the keratocytes, that were migrating into the wound. No other changes were noted. None of these features were modulated when granulocyte emigration was prevented by fucoidin administration. Conclusions: The difference in bFGF expression between the corneal and conjunctival epithelium suggests a role for this growth factor in the barrier function at the limbus. Moreover, the specific presence of bFGF in cells migrating into the wound indicates the participation of bFGF in corneal wound healing. Expression of bFGF was independent of granulocytes.
Investigative Opthalmology & Visual Science, 2009
PURPOSE. To determine the relationship between signaling by different growth factors and the phases of corneal stromal wound repair. The authors hypothesize that the process involves sequential signaling, resulting first in proliferation and then in extracellular matrix (ECM) synthesis. METHODS. The effects of IGF-I, TGF-1, FGF-2, and PDGF on proliferation and ECM production by primary cultured bovine keratocytes were evaluated. DNA synthesis was determined by 3 H-thymidine incorporation, and maximal cell density was determined by measurement of DNA content. Relative levels of ECM components synthesized by keratocytes and secreted into the media were evaluated by 3 H-glycine incorporation into total ECM protein and collagen, by 3 H-glucosamine incorporation into chondroitin sulfate, keratan sulfate, and hyaluronan, and by Western blotting with antibodies specific to procollagen types ⌱ and ⌱⌱⌱. RESULTS. FGF-2 stimulated the highest level of proliferation and the lowest level of glycosaminoglycan synthesis and inhibited the synthesis of collagen types ⌱ and ⌱⌱⌱. IGF-I, in contrast, stimulated the lowest level of proliferation and the highest levels of collagen synthesis. PDGF and TGF-1 had intermediate effects on proliferation and collagen synthesis. Although FGF-2 inhibited collagen production, it could be restored by subsequent treatment with IGF-I, TGF-1, and PDGF. CONCLUSIONS. The results of this study showed that the level of proliferation induced by the growth factors was inversely related to the levels of collagen production. The authors suggest that FGF-2 initiates the hypercellular phase of corneal wound healing and that IGF-I and PDGF are involved in the restoration of a normal ECM.
TGF-b Receptor Types I and II Are Differentially Expressed during Corneal Epithelial Wound Repair
2001
PURPOSE. It has been demonstrated that cells migrating to cover an epithelial débridement wound exit the cell cycle and that the cell-cycle inhibitor p15 INK4b is upregulated in these cells. TGF- signaling has been implicated in both of these processes, and this study was conducted to determine whether the expression and localization of TGF- receptor (TR)-I and -II are altered during corneal epithelial wound repair.
Experimental Eye Research, 1992
Prior to a clinical trial in humans, we studied the effect and pharmacological distribution of recombinant human basic fibroblast growth-factor (Rh-bFGF) in vivo. Healing experiments on de-epithelialized rabbits corneas (n = 24 animals) compared the efficacy of three bFGF doses to controls and revealed a significantly increased healing rate for both 200 ng and 500 ng per application Rh-bFGF treatment groups compared to the control groups. To assess possible side effects of Rh-bFGF (500 ng topically applied for up to 7 days, twice daily), ten rabbits were involved in a model of an anterior keratectomy wound (performed with Draeger's roto-keratome to a depth of 0.15 mm). Light microscopy of thin sections of treated corneas showed an increased fibrogenesis in the anterior stroma with a more pronounced activation of keratocytes. No evidence for abnormal neovascularization or inflammation was observed when compared to control corneas. Ocular penetration and systemic distribution of topically applied labelled 125T FGF was assessed in three models (iodine vapour epithelial burn, anterior keratectomy and penetrating autokeratoplasty) in 24 rabbits. No intraocular penetration of bFGF occurred as shown by direct gamma counting. Macroautoradiography showed a selective labelling of epithelial basement membrane when denuded and intact, as previously described. Evidence for systemic absorption of breakdown products was confirmed by heparin-sepharose chromatography of blood and urine samples. Under these conditions. we suggest that topical Rh-bFGF promotes cornea1 wound healing without morphological adverse reaction or intraocular and systemic penetration.
Acta Ophthalmologica Scandinavica, 2005
To study the expression of basic fibroblast growth factor (bFGF) in the early phases of corneal wound healing in the presence or absence of granulocytes. A central penetrating corneal alkali wound was inflicted to one eye in each of 14 rabbits under general anaesthesia. Subsequently, seven of the rabbits were given fucoidin i.v. for 36 hours in order to block the selectins on the vascular endothelium, thus preventing blood granulocytes from entering the tissues. Then, corneas were prepared, stained for bFGF and evaluated by light microscopy. Whereas normal corneal epithelium expressed bFGF weakly, conjunctival epithelium did so strongly, particularly the goblet cells. The corneal endothelium showed medium staining, while keratocytes and vascular endothelial cells did not consistently express bFGF. After 36 hours of wound healing, a marked up-regulation of bFGF expression was observed in the corneal epithelial and endothelial cells, as well as in the keratocytes, that were migrating into the wound. No other changes were noted. None of these features were modulated when granulocyte emigration was prevented by fucoidin administration. The difference in bFGF expression between the corneal and conjunctival epithelium suggests a role for this growth factor in the barrier function at the limbus. Moreover, the specific presence of bFGF in cells migrating into the wound indicates the participation of bFGF in corneal wound healing. Expression of bFGF was independent of granulocytes.
Comparison of the effects of EGF, pFGF and EDGF on corneal epithelium wound healing
1984
EDGF, a growth factor purified from bovine retina is able to increase the rate of wound healing of rabbit corneal epithelium in a dose dependent way. Two applications a day are enough to obtain the maximum rate. The most purified preparation of EDGF is as effective as EGF or pFGF in promoting this phenomenon and allows the epithelium to reach its normal organization earlier. Excess addition of EDGF did not adversely affect the normal or healed epithelium.