Immunohistochemical Profile of Tumor Suppressor Proteins RASSF1A and LATS1/2 in Relation to p73 and YAP Expression, of Human Inflammatory Bowel Disease and Normal Intestine.

The intestinal neoplastic transformation is a possible risk of chronic inflammatory bowel disease (IBD). Previous evidence in mice IBD provides a role for the RAS-association domain family tumor suppressor protein 1 A (RASSF1A), in the repairing process following mucosa epithelium damage, through cooperation with the HIPPO-signaling molecules p73, and YAP. HIPPO pathway which has been implicated in stem cell activity includes as key components for signal transduction the large tumor suppressor homology Ser/Thr kinases LATS1/2. The aim of this study was to assess immunohistochemically, using specific antibodies, the RASSF1A and LATS1/2 expression patterns in a cohort of patients with IBD including 52 ulcerative colitis (UC), 24 Crohn's disease (CD) and 24 IBD unclassified (IBD-U), compared with normal intestine from non-IBD patients (control group). The relationship between subtypes of IBD and RASSF1A and LATS1/2 expression, both individually and related to p73 and YAP/pYAP(Ser127) proteins was also investigated. Quantitative analyses of the immunohistochemical findings in mucosa cells revealed a significantly decreased expression in UC and IBD-U for RASSF1A expression and a significantly elevated expression in UC, IBD-U, and CD for LATS1/2 expression compared with normal mucosa (P < 0.05). However, ROC curve analysis showed that only LATS1/2 could differentiate IBD from control group. RASSF1A expression was significantly correlated with LATS1/2 in UC with dysplasia (P < 0.0001), and p73 in UC (P < 0.001), and IBD-U (P < 0.02). The expression of all proteins did not differ significantly between subtypes of IBD (P ≥ 0.05). RASSF1A-LATS1/2 co-expression was mainly observed in IBD samples. These findings suggest that tumor suppression proteins RASSF1A and LATS1/2 may be involved in the pathogenesis of human IBD and imply a potential cooperation of RASSF1A, and HIPPO signaling pathways in human bowel inflammation.

Immunolocalization of cannabinoid receptor type 1 and CB2 cannabinoid receptors, and transient receptor potential vanilloid channels in pterygium.

Cannabinoids, as multi­target mediators, activate cannabinoid receptors and transient receptor potential vanilloid (TRPV) channels. There is evidence to support a functional interaction of cannabinoid receptors and TRPV channels when they are coexpressed. Human conjunctiva demonstrates widespread cannabinoid receptor type 1 (CB1), CB2 and TRPV channel localization. The aim of the present study was to investigate the expression profile for cannabinoid receptors (CB1 and CB2) and TRPV channels in pterygium, an ocular surface lesion originating from the conjunctiva. Semi­serial paraffin­embedded sections from primary and recurrent pterygium samples were immunohistochemically examined with the use of specific antibodies. All of the epithelial layers in 94, 78, 96, 73 and 80% of pterygia cases, exhibited CB1, CB2, TRPV1, TRPV2 and TRPV3 cytoplasmic immunoreactivity, respectively. The epithelium of all pterygia cases (100%) showed strong, mainly nuclear, TRPV4 immunolocalization. In the pterygium stroma, scattered cells demonstrated intense CB2 immunoreactivity, whereas vascular endothelial cells were immunopositive for the cannabinoid receptors and all TRPV channels. Quantitative analyses of the immunohistochemical findings in epithelial cells demonstrated a significantly higher expression level in conjunctiva compared with primary pterygia (P=0.04) for CB1, but not for CB2 (P>0.05). Additionally, CB1 and CB2 were significantly highly expressed in primary pterygia (P=0.01), compared with recurrent pterygia. Furthermore, CB1 expression levels were significantly correlated with CB2 expression levels in primary pterygia (P=0.005), but not in recurrent pterygia (P>0.05). No significant difference was detected for all TRPV channel expression levels between pterygium (primary or recurrent) and conjunctival tissues (P>0.05). A significant correlation between the TRPV1 and TRPV3 expression levels (P<0.001) was detected independently of pterygium recurrence. Finally, TRPV channel expression was identified to be significantly higher than the expression level of cannabinoid receptors in the pterygium samples (P<0.001). The differentiated expression of cannabinoid receptors in combination with the presence of TRPV channels, in primary and recurrent pterygia, imply a potential role of these cannabinoid targets in the underlying mechanisms of pterygium.