A previous whole-genome microarray of affected and unaffected ileocecal resection specimens from Crohn's disease (CD) patients, showed a TMIGD1 differential expression (FC=-109 and -26; FDR=0 in unaffected and affected mucosa, respectively) compared to controls. TMIGD1 function is unknown in CD, and only existing data comes from colorectal cancer (Cattaneo, E et al.EMBO mol med.2011)
Objectives
To define functional and molecular TMIGD1 expression changes between affected and unaffected CD ileocecal resections.
Methods
TMIGD1 gene expression (Codelink microarrays) has corroborated by Taqman assay-PCR (Lifetechnologies), protein and glycosylation level has analyzed by Western-blot and GlycoProfileTM-II (Sigma-Aldrich) test, respectively. By double immunolabeling (TMIGD1 vs NOD2 or Sucrase-isomaltase) has used to determinate their spatial localization in different mucosal compartments.
Results
RT-qPCR correlates with TMIGD1 gene expression profiling results (Pearson correlation =-0.8 and r2 0.66). Enzymatic assay and western-blot reveal that TMIGD1 is non-glycosylated protein, whereas it could be a truncated isoform (http://www.uniprot.org/). TMIGD1/Sucrase-isomaltase immunofluorescence shows continuous apical microvilli localization in healthy differentiated cells, but not in affected mucosa.
Conclusions
Despite the lack of knowledge about TMIGD1 function, our study demonstrates that presence of an apical truncated form in epithelial cells is associated with cell differentiation and inflammation degree.