Innate Immun. 2017 Jan;23(1):44-53. doi: 10.1177/1753425916674263.

New IL-15 receptor-α splicing variants identified in intestinal epithelial Caco-2 cells.

Escudero-Hernández C1, Martínez-Abad B1, Ruipérez V1, Garrote JA1,2, Arranz E1.

1 Mucosal Immunology Laboratory, Instituto de Biología y Genética Molecular (IBGM), University of Valladolid-CSIC, Valladolid, Spain.
2 Laboratory of Molecular Genetics, Hospital Universitario Rio Hortega, Valladolid, Spain.

 

Abstract

IL-15 is a pleiotropic cytokine related to IL-2 which acts at a broader level than its counterpart. It is presented through its specific high-affinity receptor, IL-15Rα. Both cytokine and receptor are tightly regulated at multiple levels and are widely distributed. Thus, deregulation of their expression leads to an inflammatory immune response. Variants of splicing of IL-15Rα have been described in immune and barrier cells; however, their presence has not been focused on intestinal epithelial cells. In this study, we describe five new alternative variants of splicing of IL-15Rα in Caco-2 cells. Four of them were expressed into proteins inside Caco-2 cells, but these were unable to bind IL-15 or to follow the secretory pathway. However, the expression of mRNA itself might be relevant to diseases such as celiac disease, inflammatory bowel disease or colorectal cancer.

KEYWORDS: Alternative splicing; cancer; disease; epigenetics; interleukin-15

PMID: 27794069

 

Supplementary pictures permitted by SAGE Publications Ltd

 

Figure 5: Immunofluorescence of transfected Caco-2 cells with pEGFP (control); isoforms containing 276 and 510 bp derived from variants, V, 1 and 2; and isoforms containing 130 and 348 bp derived from variant 3. Cell nucleus are shown in blue, EGFP fused proteins are shown in green and specific cell-compartment dyeing are shown in red. Calnexin was used to detect the endoplasmic reticulum; coatomer protein B, COPB, was used to detect the Golgi apparatus; and lysosomal membrane-associated protein 1, LAMP1, was used to detect the lysosomes. Images were taken in a confocal Leica microscope (63x objective). The bars indicate a size of 10 mm.

 

 

Figure 7: Expression of IL-15Ra isoforms in biopsy samples from healthy donors quantified by PCR. C, colon samples; D, duodenal samples; bp, base pairs; V, variant.