Conditional Abatement of Tissue Fibrosis Using Nucleoside Analogs to Selectively Corrupt DNA Replication in Transgenic Fibroblasts

Abstract

Progressive tissue fibrosis can compromise epithelial function resulting in organ failure. Appreciating evidence suggests that fibroblasts provide fibrogenic collagens during such injury. We further tested this notion by attempting to reduce the physiologic consequences of organ fibrosis through the selective killing of fibroblasts at sites of injury. Here, we report the conditional reduction of tissue fibroblasts using the coding sequence for herpesvirus thymidine kinase (DeltaTK) put under the control of a cell-specific promoter from the gene encoding fibroblast-specific protein 1 (FSP1). Transgenic fibroblasts from mice carrying FSP1.DeltaTK minigenes expressed thymidine kinase concordantly with native FSP1 and, compared to transgenic epithelium, were selectively susceptible to the lethal effects of nucleoside analogs either in culture or during experimental renal fibrosis. The numbers of fibroblasts in fibrogenic kidney tissue were reduced on exposure to nucleoside analogs as was the degree of type I collagen deposition and the extent of fibrosis. Fibroblast reduction following the stress of DNA chain termination highlights the important contribution of cell division during fibrogenesis. Our findings convey a proof of principle regarding the importance of FSP1(+) fibroblasts in fibrosis as well as providing a new approach to treating the relentless scarification of tissue.

Pericytes and Perivascular Fibroblasts Are the Primary Source of Collagen-Producing Cells in Obstructive Fibrosis of the Kidney

“…40 However our studies identify S100A4 in macrophages and not in collagen producing cells. We have previously demonstrated an important role for macrophages in the development of fibrosis in the kidney and other organs.…”

FSP1+ Fibroblasts Promote Skin Carcinogenesis by Maintaining MCP-1-Mediated Macrophage Infiltration and Chronic Inflammation

“…And in normal mice, it has been proved that FSP1 is specific for fibroblasts by genetic and protein criteria. 18 Also, we have found that no expression of FSP1 in F4/80 ϩ macrophages and CD31 ϩ endothelial cells in TPA-treated mouse skin tissues (see Supplemental Figure S4, http://ajp.amjpathol.org). Therefore, during our experiments, FSP1 was used as the marker for fibroblasts in TPA-treated skin.…”

“…18 Fibroblasts were seeded in 24 multiwell plates (1 ϫ 10 5 cells/well) in serum-free DMEM and were treated with or without 10 nmol/L TPA for 24 hours. Then the fibroblast-conditioned medium was collected.…”

S100A4 promotes colon inflammation and colitis-associated colon tumorigenesis

“…To explore the role of S100A4 + cells in the development of CRC, S100A4-thymidine kinase (TK) transgenic mice were used, 22 , 39 and proliferating S100A4 + cells in these mice could be selectively depleted upon the treatment of ganciclovir (GCV) after the administration of AOM/DSS, as illustrated in Fig. 3A.…”