Molecular mechanism of benign biliary stricture inhibition by rosiglitazone-activated peroxisome proliferator-activated receptor gamma

SUMMARY OBJECTIVE: The aim of this study was to investigate whether rosiglitazone-activated peroxisome proliferator-activated receptor gamma can inhibit the occurrence of benign biliary stricture and further elucidate the relevant molecular signaling mechanism. METHODS: The primary cultured rat biliary fibroblasts following experiments were performed using within the fifth generation cells, which were separated from the bile ducts of Sprague-Dawley rats. The primary cultured rat biliary fibroblasts were co-cultured with 10 ng/mL transforming growth factor-beta 1 for stimulating collagen formation. Competent cells were transfected with siRNA that specifically target Smad3 or connective tissue growth factor to inhibit the expression of the corresponding proteins. The cells were incubated with 10 μmol/L rosiglitazone to activate peroxisome proliferator-activated receptor gamma. The cells were incubated with 10 μmol/L GW9662 in the pretreatment session to inactivate peroxisome proliferator-activated receptor gamma. ELISA was used to determine the levels of connective tissue growth factor and type I collagen in the cell supernatant. Western blotting was used to detect the levels of intracellular p-Smad3/t-Smad3. RESULTS: Rosiglitazone-activated peroxisome proliferator-activated receptor gamma inhibited the secretion of type I collagen induced by transforming growth factor-beta 1. Peroxisome proliferator-activated receptor gamma inhibitor GW9662 could significantly reverse the rosiglitazone-triggered inhibition of transforming growth factor-beta 1-induced type I collagen secretion by suppressing peroxisome proliferator-activated receptor gamma activation (p<0.01). Furthermore, we also found that the activation of peroxisome proliferator-activated receptor gamma was accompanied by the inhibition of transforming growth factor-beta 1-induced Smad3 phosphorylation (p<0.01), increased connective tissue growth factor expression (p<0.01), and production of type I collagen (p<0.01), all of which effects elicited by rosiglitazone could be reversed by peroxisome proliferator-activated receptor gamma inhibitor GW9662. CONCLUSION: Peroxisome proliferator-activated receptor gamma activated by rosiglitazone inhibits the transforming growth factor-beta1 -induced phosphorylation of Smad3 and the increased connective tissue growth factor expression as well as inhibits the secretion of type I collagen in biliary fibroblasts.

Descemet's membrane injury and regeneration, and posterior corneal fibrosis, in rabbits.

The purpose of this investigation was to study Descemet's membrane and corneal endothelial regeneration, myofibroblast generation and disappearance, and TGF beta-1 localization after Descemet's membrane-endothelial excision (Descemetorhexis) in rabbits. Thirty-six rabbits had 8 mm Descemetorhexis and standardized slit lamp photos at 1, 2 and 4 days, 1, 2 and 4 weeks, and 2, 4 and 6 months, as well as multiplex IHC for stromal cell markers keratocan, vimentin, and alpha-smooth muscle actin (SMA); basement membrane (BM) components perlecan, nidogen-1, laminin alpha-5, and collagen type IV; and corneal endothelial marker Na,K-ATPase ß1, and TGF beta-1, with ImageJ quantitation. Stromal transparency increased from the periphery beginning at two months after injury and progressed into the central cornea by six months. At six months, central transparency was primarily limited by persistent mid-stromal neovascularization. Stromal myofibroblast zone thickness in the posterior stroma peaked at one month after injury, and then progressively decreased until to six months when few myofibroblasts remained. The regeneration of a laminin alpha-5 and nidogen-1 Descemet's membrane "railroad track" structure was accompanied by corneal endothelial closure and stromal cell production of BM components in corneas from four to six months after injury. TGF beta-1 deposition at the posterior corneal surface from the aqueous humor peaked at one day after Descemetorhexis and diminished even before regeneration of the endothelium and Descemet's membrane. This decrease was associated with collagen type IV protein production by corneal fibroblasts, and possibly myofibroblasts, in the posterior stroma. Descemet's membrane and the corneal endothelium regenerated in the rabbit cornea by six months after eight mm Descemetorhexis. Real-time quantitative RT-PCR experiments in vitro with marker-verified rabbit corneal cells found that 5 ng/ml or 10 ng/ml TGF beta-1 upregulated col4a1 or col4a2 mRNA expression after 6 h or 12 h of exposure in corneal fibroblasts, but not in myofibroblasts. Stromal cells produced large amounts of collagen type IV that likely decreased TGF beta-1 penetration into the stroma and facilitated the resolution of myofibroblast-generated fibrosis.

Effects of TGF-ß1 on mineralization mediated by rat calvaria-derived osteogenic cells.

In this study, we have analyzed the viability and cell growth, as well as, the mineralization of extracellular matrix (ECM) by alizarin red and von Kossa staining of calvaria-derived osteogenic cultures, treated with TGF-ß1 alone or associated with Dex comparing with acid ascorbic (AA) + ß-glicerophosphate (ßGP) (positive mineralization control). The expression of the noncollagenous proteins bone sialoprotein (BSP), osteopontin (OPN) and fibronectin (FN) were evaluated by indirect immunofluorescence. In addition, the main ultrastructural morphological findings were assessed by transmission electron microscopy. Osteogenic cells were isolated of calvaria bone from newborn (2-day-old) Wistar rats were treated with TGF-ß1 alone or with dexamethasone for 7, 10, and 14 days. As positive mineralization control, the cells were supplemented only with AA+ ßGP. As negative control, the cells were cultured with basal medium (α-MEM + 10%FBS + 1%gentamicin). The treatment with TGF-ß1, even when combined with Dex, decreased the viability and cell growth when compared with the positive control. Osteoblastic cell cultures were positive to alizarin red and von Kossa stainings after AA + ßGP and Dex alone treatments. Positive immunoreaction was found for BSP, OPN and FN in all studied treatments. Otherwise, when the cell cultures were supplemented with TGF-ß1 and TGF-ß1 + Dex, no mineralization was observed in any of the studied periods. These present findings suggest that TGF-ß1, in the studied in vitro doses, inhibits the proliferation and differentiation of osteoblastic cells by impairment of nodule formation.

Diabetes mellitus affects the biomechanical function of the callus and the expression of TGF-beta1 and BMP2 in an early stage of fracture healing

Transforming growth factor beta 1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) are important regulators of bone repair and regeneration. In this study, we examined whether TGF-β1 and BMP-2 expressions were delayed during bone healing in type 1 diabetes mellitus. Tibial fractures were created in 95 diabetic and 95 control adult male Wistar rats of 10 weeks of age. At 1, 2, 3, 4, and 5 weeks after fracture induction, five rats were sacrificed from each group. The expressions of TGF-β1 and BMP2 in the fractured tibias were measured by immunohistochemistry and quantitative reverse-transcription polymerase chain reaction, weekly for the first 5 weeks post-fracture. Mechanical parameters (bending rigidity, torsional rigidity, destruction torque) of the healing bones were also assessed at 3, 4, and 5 weeks post-fracture, after the rats were sacrificed. The bending rigidity, torsional rigidity and destruction torque of the two groups increased continuously during the healing process. The diabetes group had lower mean values for bending rigidity, torsional rigidity and destruction torque compared with the control group (P<0.05). TGF-β1 and BMP-2 expression were significantly lower (P<0.05) in the control group than in the diabetes group at postoperative weeks 1, 2, and 3. Peak levels of TGF-β1 and BMP-2 expression were delayed by 1 week in the diabetes group compared with the control group. Our results demonstrate that there was a delayed recovery in the biomechanical function of the fractured bones in diabetic rats. This delay may be associated with a delayed expression of the growth factors TGF-β1 and BMP-2.

Blood cells and endothelial barrier function.

The barrier properties of endothelial cells are critical for the maintenance of water and protein balance between the intravascular and extravascular compartments. An impairment of endothelial barrier function has been implicated in the genesis and/or progression of a variety of pathological conditions, including pulmonary edema, ischemic stroke, neurodegenerative disorders, angioedema, sepsis and cancer. The altered barrier function in these conditions is often linked to the release of soluble mediators from resident cells (e.g., mast cells, macrophages) and/or recruited blood cells. The interaction of the mediators with receptors expressed on the surface of endothelial cells diminishes barrier function either by altering the expression of adhesive proteins in the inter-endothelial junctions, by altering the organization of the cytoskeleton, or both. Reactive oxygen species (ROS), proteolytic enzymes (e.g., matrix metalloproteinase, elastase), oncostatin M, and VEGF are part of a long list of mediators that have been implicated in endothelial barrier failure. In this review, we address the role of blood borne cells, including, neutrophils, lymphocytes, monocytes, and platelets, in the regulation of endothelial barrier function in health and disease. Attention is also devoted to new targets for therapeutic intervention in disease states with morbidity and mortality related to endothelial barrier dysfunction.

Transforming Growth Factor -beta 1 (TGF-beta 1) immunoreactivity in heterotopic grafts of adult dental apical papilla / Inmunoreactividad del Factor Transformador del Crecimiento-beta 1 (TGF-beta 1) en la papila apical dental adulta heterotópicamente trasplantada

To analyze the expression of transforming growth factor-beta 1 inheterotopic grafts of adult dental apical papilla. Methodology: The apical papilla of adult Wistar rats was grafted in the ear of the same donor rats. 1, 3, 7 and14 days after grafting, rats were perfused and the tissue containing the graft was processed for histological conventional technique and for immunohistochemical detection of transforming growth factor-beta 1. Results: Heterotopically grafted apical papilla developed osteoid dentine. In an early post-grafting stage, odontoblast-like cells organized themselves in palisade and synthesized dentine. However, newly formed dentine possessed the structural appearance of reactive osteoid dentine, which was systematically destroyed by the activity of osteoclaste-like cells. Transforming Growth Factor-beta 1 was observed in mesenchymal cells, extracellular matrix of the graft and surrounding host tissue, while odontoblast-like cells were systematically devoid of immunoreactivity. Conclusion: The different expression of transforming growth factor-beta 1 between normal tissue and grafted tissue development suggests that in heterotopic graft conditions the inflammatory mediation of the transforming growth factor-beta 1 prevails against its morphogenetic role...

Analizar la expresión del factor transformador del crecimiento-beta1 en trasplantes heterotópicos de papila dental del incisivo de la rata adulta. Metodología: La papila apical del incisivo de 12 ratas Wistar adultas fue trasplantada en la oreja de las mismas ratas donantes, y perfundidas 1, 3, 7 y 14 días postrasplante. El tejido fue procesado para histología convencionaly para la detección inmunohistoquímica del factor transformador del crecimiento-beta1. Resultados: La papila apical trasplantada desarrolló osteodentina. En fases tempranas postrasplante se observaron células parecidas a los odontoblastos que se organizaron en empalizada y segregaron dentina que se depositó sobre su superficie apical o secretora. Esta dentina evolucionó a osteodentina caracterizada por perder su estructura tubular e incluir a las células odontoblásticas en lagunas de su matriz. Finalmente, la osteodentina presentó procesos líticos mediados por células de tipo osteoclasto. Durante todo el proceso la expresión del factor transformador del crecimiento-beta1 se restringió a las células mesenquimales, a la matriz del trasplante y a las zonas circundantes del huésped, estando ausente en los odontoblastos, a diferencia de lo que sucede durante la odontogénesis normal. Conclusión: La diferente localización de la expresión del Factor Transformador de crecimiento beta1 entre el tejido hospedero y el trasplantado sugieren que en condiciones de trasplante heterotópico de papila dental la mediación inflamatoria del Factor Transformador de crecimiento beta1 prevalece sobre su papel morfogenético...

EPAC expression and function in cardiac fibroblasts and myofibroblasts.

UNLABELLED: In the heart, cardiac fibroblasts (CF) and cardiac myofibroblasts (CMF) are the main cells responsible for wound healing after cardiac insult. Exchange protein activated by cAMP (EPAC) is a downstream effector of cAMP, and it has been not completely studied on CF. Moreover, in CMF, which are the main cells responsible for cardiac healing, EPAC expression and function are unknown. We evaluated in both CF and CMF the effect of transforming growth factor ß1 (TGF-ß1) on EPAC-1 expression. We also studied the EPAC involvement on collagen synthesis, adhesion, migration and collagen gel contraction. METHOD: Rat neonatal CF and CMF were treated with TGF-ß1 at different times and concentrations. EPAC-1 protein levels and Rap1 activation were measured by western blot and pull down assay respectively. EPAC cellular functions were determined by adhesion, migration and collagen gel contraction assay; and collagen expression was determined by western blot. RESULTS: TGF-ß1 through Smad and JNK significantly reduced EPAC-1 expression in CF, while in CMF this cytokine increased EPAC-1 expression through ERK1/2, JNK, p38, AKT and Smad3. EPAC activation was able to induce higher Rap1-GTP levels in CMF than in CF. EPAC and PKA, both cAMP effectors, promoted CF and CMF adhesion on fibronectin, as well as CF migration; however, this effect was not observed in CMF. EPAC but not PKA activation mediated collagen gel contraction in CF, while in CMF both PKA and EPAC mediated collagen gel contraction. Finally, the EPAC and PKA activation reduced collagen synthesis in CF and CMF. CONCLUSION: TGF-ß1 differentially regulates the expression of EPAC in CF and CMF; and EPAC regulates differentially CF and CMF functions associated with cardiac remodeling.

Estudo imuno-histoquímico da presença de miofibroblastos e da expressão do fator transformador de crescimento-beta1, interferon gama, mataloproteinase de matriz 13 e indutor de metaloproteinases de matriz em lesões odontogênicas epiteliais / Immunohistochemical study of the presence of myofibroblasts and the expression of transforming growth factor-beta1, interferon gamma, mataloproteinase matrix 13 and matrix metalloproteinase inducer in odontogenic epithelial lesions

Os miofibroblastos são células que apresentam um fenótipo híbrido exibindo características morfológicas de fibroblastos e de células musculares lisas, sendo a aquisição de tal fenótipo denominada diferenciação, passando então a expressar a a-SMA, a qual é importante na identificação dessas células. Estudos têm sugerido que os miofibrobíastos apresentam relação com a agressividade de diversas lesões e que o seu processo de diferenciação estaria relacionado à expressão do TGF-pl e do IFN-y atuando, respectivamente, no estímulo e na inibição dessa diferenciação. O objetivo deste trabalho foi investigar o papel dos miofibroblastos em lesões odontogênicas epiteliais, relacionando-os à agressividade das lesões e analisar por meio da imuno-histoquímica. a expressão do TGF-pl e IFN-y no processo de diferenciação, além da análise da MMP-13 que é ativada por miofibroblastos e do indutor de metaloproteinases de matriz (EMMPRIN) como precursor desta MMP. A amostra foi constituída por 20 ameloblastomas sólidos, 10 ameloblastomas unicfsticos, 20 ceratocistos odontogênicos e 20 tumores odontogênícos adenomatóides. Para a avaliação dos miofibroblastos, foram quantificadas as células imunorreativas ao anticorpo a-SMA presentes no tecido conjuntivo, próximo ao tecido epitelial. As expressões de TGF-pl, IFN-y, MMP-13 e EMMPRIN, foram avaliadas no componente epitelial e no conjuntivo, estabelecendo-se o percentual de imunorreatividade e atribuindo-se escores de 0 a 4. A análise dos miofibroblastos evidenciou maior concentração nos ameloblastomas sólidos (média de 30,55), seguido pelos ceratocistos odontogênicos (22,50), ameloblastomas unicísticos (20,80) e tumores odontogênicos adenomatóides (19,15) com valor de p= 0,001. Não foi encontrada correlação significativa entre TGF-pl e IFN-y no processo de diferenciação dos miofibroblastos, bem como na relação entre a quantidade de miofibroblastos e a expressão da MMP-13. Constatou-se, correlação estatística entre MMP-13 e TGF-pi (r= 0,087; p= 0,011) além de significante correlação entre MMP-13 e IFN-y (r=0,348; p=0,003). Entre EMMPRÍN e MMP-13 verificou-se significância (r= 0,474; p<0,001) assim como entre EMMPRIN e IFN-y (r=0,393; p=0,001). A maior quantidade de miofibroblastos evidenciada nos ameloblastomas sólidos, ceratocistos odontogênicos e ameloblastomas unicísticos sugere que estas células podem ser um dos fatores responsáveis para um comportamento biológico mais agressivo destas lesões, embora a população de miofibroblastos não tenha apresentado correlação com TGF- -pi, IFN-y ,MMP-13 e EMMPRIN. Quanto a correlação evidenciada entre MMP-13 e TGF-pl, isto pode sugerir um papel indutor do TGF-pl para a expressão da MMP-13, assim como os resultados deste estudo reforçam a relação bem estabelecida do EMMPRIN como indutor da MMP-13. Constatou-se também relação entre EMMPRIN e IFN-y assim como entre MMP-13 e IFN-y sugerindo, dessa forma, um sinergismo na ação anti-fibrótica desses marcadores.

Myofibroblasts are cells that exhibit a hybrid phenotype, sharing the morphoíogical characteristics of fibroblasts and smooth muscle cells, which is acquired during a process called differentiation. These cells then start to express a-SMA, a marker that can be used for their identification. Studies suggest that myofibroblasts are related to the aggressiveness of different tumors and that TGF-pl and IFN-y play a role in myofibroblast differentiation, stimulating or inhibiting this differentiation, respectively. The objective of this study was to investigate the role of myofibroblasts in epithelial odontogenic tumors, correlating the presence of these cells with the aggressiveness of the tumor. Immunohistochemistry was used to evaluate the expression of TGF-pl and IFN-y in myofibroblast differentiation, as well as the expression of MMP-13, which is activated by myofibroblasts, and of EMMPRIN (extracellular matrix metalloproteinase inducer) as a precursor of this MMP. The sample consisted of 20 solid ameloblastomas, 10 unicystic ameloblastomas, 20 odontogenic keratocysts, and 20 adenomatoid odontogenic tumors. For evaluation of myofibroblasts, anti-a-SMA-immunoreactive cells were quantified in connective tissue close to the epithelium. Immunoexpression of TGF-pl, IFN-y, MMP-13 and EMMPRIN was evaluaíed in the epithelial and connective tissue components, attributing scores of 0 to 4. The results showed a higher concentration of myofibroblasts in solid ameloblastomas (mean of 30.55), followed by odontogenic keratocysts (22.50), unicystic ameloblastomas (20.80), and adenomatoid odontogenic tumors (19.15) (p=0.00). No significant correlation between TGF-pl and IFN-y was observed during the process of myofibroblast differentiation. There was also no correlation between the quantity of myofibroblasts and MMP-13 expression. Significant correlations were found between MMP-13 and TGF-pi (r=0.087; p=0.01 1), between MMP-13 and ÍFN-y (r=0.348; p=0.003), as well as between EMMPRIN and MMP-13 (r=0.474; /xO.001) and between EMMPRIN and IFN-y (r=0.393; p=0.00). The higher quantity of myofibroblasts observed in solid ameloblastomas, odontogenic keratocysts and unicystic ameloblastomas suggests that these cells are one of the factors responsible for the more aggressive biological behavior of these tumors, although the myofibroblast population was not correlated with TGF-01, IFN-y, MMP-13 or EMMPRIN. The correlation between MMP-13 and TGF-pl suggests that the latter induces the expression of this metalloproteinase. The present results also support the well-established role of EMMPRIN as an inducer of MMP-13. Furthermore, the relationship between EMMPRIN and IFN-y and between MMP-13 and IFN-y suggests synergism in the antifibrotic effect of these markers.

Associação dos polimorfismos dos genes TGF-beta1, CD14, IL-4, IL-4R e ADAM33 com a gravidade da asma em crianças e adolescentes / Association of TGF-beta1, CD14, IL-4, IL-4R and ADAM33 gene polymorphisms with asthma severity in children and adolescents

OBJETIVO: Verificar, em uma amostra de pacientes com asma atópica persistente leve, moderada e grave, a associação entre os polimorfismos dos genes fator de crescimento transformante-beta1 (TGF-beta1) (C-509T e T869C), CD14 (C-159T), IL-4 (C-590T), IL-4R (ILe50Val) e ADAM33 (S_2) com a gravidade da asma. MÉTODOS: Realizou-se um estudo clínico laboratorial prospectivo em pacientes com asma atópica persistente, comparados a um grupo controle no Hospital Universitário da Universidade Estadual de Campinas nos anos de 2006 e 2007. A análise do polimorfismo T869C do gene TGF-beta1 foi realizada pela técnica de reação em cadeia da polimerase (PCR) + sistema de amplificação refratária de mutação (ARMS). Os outros polimorfismos, C-509T do gene TGF-beta1, C-159T do gene CD14, C-590T da IL-4, ILe50Val da IL-4Ra e S2 do gene ADAM33, foram detectados por PCR e enzima de restrição. RESULTADOS: Foram incluídos 88 pacientes com asma atópica persistente (27 leves, 23 moderados e 38 graves) e 202 indivíduos saudáveis, doadores de sangue. Em relação ao polimorfismo T869C (TGF-beta1), observou-se uma associação entre o genótipo CC e os pacientes com asma grave. Nenhuma associação foi encontrada com os polimorfismos C-509T (TGF-beta1), C-590T (IL4) e S_2 (ADAM33). Quando se comparou a distribuição da freqüência genotípica do polimorfismo C-159T (CD14) na asma grave com o grupo controle, foi observado um resultado significativo com o genótipo TT. Houve associação significativa do genótipo Val/Val (IL-4R) com a asma leve. CONCLUSÃO: Nossos resultados indicam que os polimorfismos T869C (TGF-beta1), C-159T (CD14) e Val/Val (IL-4R) podem estar envolvidos na modulação da gravidade da asma.

OBJECTIVE: To verify the association of transforming growth factor-beta1 (TGF-beta1) (C-509T and T869C), CD14 (C-159T), IL-4 (C-590T), IL-4R (ILe50Val) and ADAM33 (S_2) gene polymorphisms with asthma severity in a sample of patients with mild, moderate and severe persistent atopic asthma. METHODS: A clinical, laboratory, prospective study was performed in patients with persistent atopic asthma, compared to a control group at Hospital Universitário da Universidade Estadual de Campinas between 2006 and 2007. Analysis of the TGF-beta1 T869C gene polymorphism was performed using the technique polymerase chain reaction (PCR) + amplification refractory mutation system (ARMS). TGF-beta1 C-509T, CD14 C-159T, IL-4 C-590T, IL-4Ra ILe50Val, and ADAM33 S2 gene polymorphisms were detected by PCR and restriction enzyme. RESULTS: This study included 88 patients with persistent atopic asthma (27 mild, 23 moderate and 38 severe) and 202 healthy blood donors. As to T869C polymorphism (TGF-beta1), there was an association between the CC genotype and patients with severe asthma. There was no association in polymorphisms C-509T (TGF-beta1), C-590T (IL-4) and S_2 (ADAM33). When distribution of C-159T polymorphism genotype frequency (CD14) in severe asthma was compared with the control group, there was a significant result with the TT genotype. There was significant association of the Val/Val genotype (IL-4R) with mild asthma. CONCLUSION: Our results indicate that T869C (TGF-beta1), C-159T (CD14) and Val/Val (IL-4R) polymorphisms might be involved in modulation of asthma severity.