Expression Analysis of Fibronectin Type III Domain-Containing (FNDC) Genes in Inflammatory Bowel Disease and Colorectal Cancer

Abstract

Background. Fibronectin type III domain-containing (FNDC) proteins fulfill manifold functions in tissue development and regulation of cellular metabolism. FNDC4 was described as anti-inflammatory factor, upregulated in inflammatory bowel disease (IBD). FNDC signaling includes direct cell-cell interaction as well as release of bioactive peptides, like shown for FNDC4 or FNDC5. The G-protein-coupled receptor 116 (GPR116) was found as a putative FNDC4 receptor. We here aim to comprehensively analyze the mRNA expression of FNDC1, FNDC3A, FNDC3B, FNDC4, FNDC5, and GPR116 in nonaffected and affected mucosal samples of patients with IBD or colorectal cancer (CRC). Methods. Mucosa samples were obtained from 30 patients undergoing diagnostic colonoscopy or from surgical resection of IBD or CRC. Gene expression was determined by quantitative real-time PCR. In addition, FNDC expression data from publicly available Gene Expression Omnibus (GEO) data sets (GDS4296, GDS4515, and GDS5232) were analyzed. Results. Basal mucosal expression revealed higher expression of FNDC3A and FNDC5 in the ileum compared to colonic segments. FNDC1 and FNDC4 were significantly upregulated in IBD. None of the investigated FNDCs was differentially expressed in CRC, just FNDC3A trended to be upregulated. The GEO data set analysis revealed significantly downregulated FNDC4 and upregulated GPR116 in microsatellite unstable (MSI) CRCs. The expression of FNDCs and GPR116 was independent of age and sex. Conclusions. FNDC1 and FNDC4 may play a relevant role in the pathobiology of IBD, but none of the investigated FNDCs is regulated in CRC. GPR116 may be upregulated in advanced or MSI CRC. Further studies should validate the altered FNDC expression results on protein levels and examine the corresponding functional consequences.

RETRACTED: FNDC1 Promotes the Invasiveness of Gastric Cancer via Wnt/β-Catenin Signaling Pathway and Correlates With Peritoneal Metastasis and Prognosis

“…The FNDC1 gene is closely related to many diseases. Wuensch (20) found that FNDC1 was associated with pathological changes in inflammatory bowel disease. Van 21performed a WES study and found that FNDC1 plays an important role in the development of acute otitis media in children.…”

The silencing of FNDC1 inhibits the tumorigenesis of breast cancer cells via modulation of the PI3K/Akt signaling pathway

“…For instance, the overexpression of FNDC1 was found to be correlated with a poor prognosis in patients with gastric cancer (11). An upregulation of FNDC1 has also been revealed in head and neck squamous cell carcinoma and colorectal cancer (12,13). However, there have been few studies regarding the roles of FNDC1 in the progression of BC.…”

G Protein-Coupled Receptors in the Mammalian Blood-Brain Barrier

“…It has been proposed that ADGRF5 and S1P 1 may Alvarez et al (2011) and Kahn (2014) function in concert to regulate the BBB (Yanagida et al, 2017). A recent report suggests ADGRF5 may also function as a receptor for fibronectin type III domain-containing proteins (FNDC;Wuensch et al, 2019). Several studies have identified ADGRA2, also known as GPR124, as a key endothelial regulator of brain-specific angiogenesis (Obermeier et al, 2013;Sweeney et al, 2019).…”