(I and J) RT-PCR analysis of FSP-1 (I) and α-SMA (J) mRNA expression in fibrotic skin tissues (n = 10 per group).
At the same time, the cytoplasm of these cells showed positive staining for a mesenchymal marker, FSP-1.
Compounding these issues, markers that initially appeared to be fibroblast-specific such as FSP-1/S100A4 have since been reported to be more widely expressed [47], [50].
Localization of type I collagen (diluted 1∶300; Abcam, USA) and FSP-1 (diluted 1∶600, A5114, DAKO, Ely, UK) were assessed in paraffin-embedded tissue sections.
Indeed, type I collagen protein deposition, as well as FSP-1, was notably decreased in the Hemin-treated group, as shown in Figure 9.
Decrease or loss of E-cadherin expression is a typical alarm signal indicating disappearance of the normal epithelial phenotype, whereas induction of FSP-1 expression is associated to the appearance of myofibroblasts and interstitial fibrosis.
In contrast, lung specimens from MHV68-infected mice demonstrated nuclear staining for TTF-1 as well as diffuse cytoplasmic staining for FSP-1 in alveolar epithelial cells (Fig. 4C).
Also, type I collagen and FSP-1 (an EMT marker) were enhanced in animals subjected only to UUO, which was not seen in the Hemin-treated group (Figure 3B, 3D, and 3E).
Thus, in addition to megalin decrease, RenTg mice showed decreased expression of E-cadherin concomitant to the appearance of tubulointerstitial fibrosis and increased expression of FSP-1; AT1 receptor antagonism reversed to normal these phenomena.
It is important to highlight, however, that late treatment with Hemin was able to reduce the expression and production of pro-fibrotic molecules, as well as type I collagen and FSP-1 deposition on the injured kidney.
In addition, virus-infected epithelial cells identified by a monoclonal antibody against the viral open reading frame 59, an early DNA replication protein, expressed the mesenchymal cell marker, FSP-1 (Fig. 4B).
