Pulmonary oxygen toxicity plays an important role in the lung injury process that leads to the development of bronchopulmonary dysplasia. Connective tissue growth factor (CTGF) is a fibroblast mitogen and promoter of collagen deposition. We investigated the effects of postnatal hyperoxia on lung collagen and CTGF expression in rats. Rat pups were exposed to 7 d of Ͼ95% O 2 and a further 3 wk of 60% O 2 . CTGF mRNA and protein expression increased after hyperoxia treatment, and the values were significantly higher in hyperoxia-exposed rats on postnatal d 7 and 14. Lung collagen levels increased as rats aged, and the values were comparable between room air-exposed and hyperoxia-exposed rats on postnatal d 7 and 14 and were significantly higher in hyperoxia-exposed rats on postnatal d 21 and 28. Increases in CTGF mRNA and protein expressions preceded the onset of increased lung collagen. These data demonstrate that CTGF is up-regulated at time points preceding the fibrotic phase of the lung injury adding credence to the hypothesis that CTGF seems to be involved in the pathogenesis of hyperoxia-induced lung fibrosis and an anti-CTGF strategy might attenuate hyperoxia-induced lung fibrosis. (Pediatr Res 62: 128-133, 2007)

Perfluorinated chemicals (PFCs) are ubiquitously distributed in the environments including stainless pan-coating, raincoat, fire extinguisher, and semiconductor products. The PPAR family has been shown to contribute to the toxic effects of PFCs in thymus, immune and excretory systems. Herein, we demonstrated that perfluorooctanesulfonate (PFOS) caused cell apoptosis through increasing ratio of Bcl-xS/xL, cytosolic cytochrome C, and caspase 3 activation in renal tubular cells (RTCs). In addition, PFOS increased transcription of inflammatory cytokines (i.e., TNFα, ICAM1, and MCP1) by NFκB activation. Conversely, PFOS reduced the mRNA levels of antioxidative enzymes, such as glutathione peroxidase, catalase, and superoxide dismutase, as a result of reduced PPARγ transactivational activity by using reporter and chromatin immuoprecipitation (ChIP) assays. PFOS reduced the protein interaction between PPARγ and PPARγ coactivator-1 alpha (PGC1α) by PPARγ deacetylation through Sirt1 upregulation, of which the binding of PPARγ and PGC1α to a peroxisome proliferator response element (PPRE) in the promoter regions of these antioxidative enzymes was alleviated in the ChIP assay. Furthermore, Sirt1 also deacetylated p53 and then increased the binding of p53 to Bax, resulting in increased cytosolic cytochrome C. The effect of PPARγ inactivation by PFOS was validated using the PPARγ antagonist GW9662, whereas the adverse effects of PFOS were prevented by PPARγ overexpression and activators, rosiglitozone and L-carnitine, in RTCs. The in vitro finding of protective effect of L-carnitine was substantiated in vivo using Balb/c mice model subjected to PFOS challenge. Altogether, we provide in vivo and in vitro evidence for the protective mechanism of L-carnitine in eliminating PFOS-mediated renal injury, at least partially, through PPARγ activation.

Myoepithelial tumors of soft tissue are uncommon neoplasms characterized histologically by spindle to epithelioid cells arranged in cords, nests, and/or reticular pattern with chondromyxoid to hyaline stroma, and genetically by rearrangement involving EWSR1 (among other less common genes) in about half of the cases. The diagnosis often requires immunostaining to confirm myoepithelial differentiation, most importantly the expression of epithelial markers and S100 protein and/or GFAP. However, there are cases wherein the morphology is reminiscent of myoepithelial tumors, while the immunophenotype falls short. Here, we report 2 highly similar myoepithelioma-like tumors arising in the hands of young adults. Both tumors were well-demarcated and composed of alternating cellular areas with palely eosinophilic hyaline stroma and scattered acellular zones of densely eosinophilic collagen deposition. The tumor cells were mainly epithelioid cells and arranged in cords or small nests. Vacuolated cells encircling hyaline matrix globules were focally prominent. A minor component of nonhyaline fibrous nodular areas composed of bland spindle cells and rich vasculature was also observed. Perivascular concentric spindle cell proliferation and perivascular hyalinization were present in some areas. The tumor cells were positive for CD34 and epithelial membrane antigen (focal) by immunostaining, while largely negative for cytokeratin, S100, GFAP, p63, GLUT1, and claudin-1. By RNA sequencing, a novel OGT-FOXO3 fusion gene was identified in case 1 and confirmed by reverse transcription polymerase chain reaction and fluorescence in situ hybridization in both cases. Sharing the unusual clinicopathologic features and the novel fusion, these 2 cases probably represent a distinct tumor entity, whose relationship with myoepithelial tumors and tumorigenic mechanisms exerted by the OGT-FOXO3 fusion remain to be studied.

We have previously reported that perfluorooctanesulfonate (PFOS) causes cell apoptosis in renal tubular epithelial cells (RTCs). Here, we extend our findings and provide evidence of epithelial-mesenchymal transition (EMT)-associated renal fibrosis caused by PFOS and the protection by l-carnitine. Our results demonstrate that PFOS increased the expression of EMT and renal injury biomarkers (eg, N-cadherin, vimentin, Snail, Kim1, and Lcn2). In addition, PFOS caused EMT induction through Sirt1-mediated PPARγ deacetylation and inactivation. l-carnitine reversed the EMT induction caused by PFOS and alleviated PFOS-mediated increases in cell migration by reactivating PPARγ through the inhibition of Sirt1 activity. The critical role of Sirt1 in this process was validated by using Sirt1 overexpression, resveratrol (a pharmacologic activator of Sirt1), nicotinamide (a Sirt1 inhibitor) and siSirt1. Nicotinamide and siSirt1, but not Sirt1 overexpression and resveratrol, alleviated PFOS-mediated EMT induction, suggesting that increased Sirt1 activity contributed to the alterations. Furthermore, through PPARγ overexpression and pharmacologic interventions, we validated the crucial role of increased PPARγ deacetylation caused by aberrant increased Sirt1 activity in RTC transformation. Similar to PPARγ overexpression, rosiglitazone (a PPARγ agonist) alleviated the effects of PFOS on the EMT-related features, whereas GW9662 (a PPARγ antagonist) mimicked the effects. The protective effect of l-carnitine was also verified in a mouse model of chronic PFOS exposure, in which decreased EMT biomarker levels and renal fibrosis by l-carnitine were observed in Western blot and histological analyses. Accordingly, l-carnitine alleviated EMT-associated renal fibrosis caused by PFOS through a Sirt1- and PPARγ-dependent mechanism.