Probes for TGF-β

CD4+ T cells that express the forkhead box P3 (FOXP3) transcription factor function as regulatory T (Treg) cells and hinder effective immune responses against cancer cells. Abundant Treg cell infiltration into tumors is associated with poor clinical outcomes in various types of cancers. However, the role of Treg cells is controversial in colorectal cancers (CRCs), in which FOXP3+ T cell infiltration indicated better prognosis in some studies. Here we show that CRCs, which are commonly infiltrated by suppression-competent FOXP3hi Treg cells, can be classified into two types by the degree of additional infiltration of FOXP3lo nonsuppressive T cells. The latter, which are distinguished from FOXP3+ Treg cells by non-expression of the naive T cell marker CD45RA and instability of FOXP3, secreted inflammatory cytokines. Indeed, CRCs with abundant infiltration of FOXP3lo T cells showed significantly better prognosis than those with predominantly FOXP3hi Treg cell infiltration. Development of such inflammatory FOXP3lonon-Treg cells may depend on secretion of interleukin (IL)-12 and transforming growth factor (TGF)-β by tissues and their presence was correlated with tumor invasion by intestinal bacteria, especially Fusobacterium nucleatum. Thus, functionally distinct subpopulations of tumor-infiltrating FOXP3+ T cells contribute in opposing ways to determining CRC prognosis. Depletion of FOXP3hi Treg cells from tumor tissues, which would augment antitumor immunity, could thus be used as an effective treatment strategy for CRCs and other cancers, whereas strategies that locally increase the population of FOXP3lo non-Treg cells could be used to suppress or prevent tumor formation.

Abstract

Purpose/Aim: Many genes have been associated with primary open-angle glaucoma (POAG). Knowing exactly where they are expressed in the eye helps to unravel POAG pathology and to select optimal targets for intervention. We investigated whether RNA in-situ hybridization (RNA-ISH) is a convenient technique to obtain detailed pan-ocular expression data of these genes. We tested this for four diverse candidate POAG genes, selected because of unclear ocular distribution (F5 and Dusp1) and relevance for potential new therapies (Tnf, Tgfβr3). Optn, a POAG gene with well-known ocular expression pattern served as control.

METHODS:

We made a list of candidate glaucoma genes reported in genetic studies. A table of their ocular expression at the tissue level was compiled using publicly available microarray data (the ocular tissue database). To add cellular detail we performed RNA-ISH for Optn, Tnf, Tgfβr3, F5, and Dusp1 on eyes of healthy, 2-month-old, pigmented and albino mice.

RESULTS:

Expression of the Optn control matched with published immunohistochemistry data. Ocular expression of Tnf was generally low, with patches of higher Tnf expression, superficially in the corneal epithelium. F5 had a restricted expression pattern with high expression in the non-pigmented ciliary body epithelium and moderate expression in the peripapillary region. Tgfβr3 and Dusp1 showed ubiquitous expression.

CONCLUSIONS:

RNA-ISH is a suitable technique to determine the ocular expression pattern of POAG genes, adding meaningful cellular detail to existing microarray expression data. For instance, the high expression of F5 in the non-pigmented ciliary body epithelium suggests a role of this gene in aqueous humor dynamics and intraocular pressure. In addition, the ubiquitous expression of Tgfβr3 has implications for designing TGF-β related glaucoma therapies, with respect to side effects. Creating pan-ocular expression maps of POAG genes with RNA-ISH will help to identify POAG pathways in specific cell types and to select targets for drug development.