Interleukin‐13 and interleukin‐33 mRNA are underexpressed in the duodenal mucosa of German Shepherd dogs with chronic enteropathy

Abstract

Background A recent genome‐wide association study in German Shepherd dogs (GSDs) with chronic enteropathy (CE) has identified polymorphisms in the Th2 cytokine genes. Hypothesis/objective To determine if the expression of the Th2 cytokines, interleukin‐13 (IL‐13) and interleukin‐33 (IL‐33), is altered in the duodenal mucosa of GSDs with CE compared to non‐GSDs with CE and healthy dogs. Animals Twenty client‐owned dogs diagnosed with CE (10 GSDs and 10 non‐GSDs) at the Bristol Veterinary School and 8 healthy Beagle dogs from the Iowa State University Service Colony. Methods Retrospective study using archived paraffin‐embedded duodenal biopsy samples. A novel RNA in situ hybridization technology (RNAscope) was used to hybridize IL‐13 and IL‐33 mRNA probes onto at least 10 sections from duodenal biopsy samples for each dog. RNAscope signals were visualized using a microscope and semi‐quantitative assessment was performed by a single operator. Results Based on duodenal villus, subvillus, epithelial, and lamina propria average expression scores, GSDs with CE had significantly lower IL‐13 and IL‐33 mRNA expression compared to non‐GSDs with CE (IL‐13, P < .04; IL‐33, P < .02) and healthy Beagle dogs (IL‐13, P < .02; IL‐33, P < .004). Conclusions and Clinical Importance Similar to human patients with ulcerative colitis, a subtype of human inflammatory bowel disease, these data indicate that Th2 cytokines may be involved in the pathogenesis of CE in GSDs.

RNAScope in situ Hybridization as a Novel Technique for the Assessment of c-KIT mRNA Expression in Canine Mast Cell Tumor

“…In particular, the recent development and availability of RNAScope represented a major improvement over traditional RNA ISH methods that are largely affected by low stability of RNA in the sample ( 43 , 44 ), often resulting in a suboptimal detection of RNA and also in poor reproducibility ( 43 ). In veterinary medicine, the use of RNAScope has begun to emerge, but it is still mainly limited to the detection of specific infectious agents ( 45 , 46 ) or inflammatory cytokines ( 47 ). With the present study, we aimed to experiment and validate the use of RNAScope in detecting and measuring the expression of c-KIT mRNA in formalin fixed and paraffin-embedded (FFPE) canine MCTs.…”

Upregulation of signal transducer and activator of transcription 3 in dogs with chronic inflammatory enteropathies

“…Previous studies in CIE dogs failed to detect signature cytokines during chronic enteric inflammation, 31,32 or a Th17 polarization 33,34 as in CD in humans 4 . However, more recent studies in dogs have described differences in the cytokine expression profiles of intestinal epithelial cells in subgroups of dogs with CIEs 35 and show involvement of Th2 cytokines in German Shepherd dog (GSD) enteropathy 36 . Other factors such as polymorphisms in the STAT3 locus as described in humans with CD and UC 37 or single nucleotide polymorphisms in genes encoding cytokines, such as those recently detected in GSD, also could play a role but were not investigated in our study.…”

Pro-inflammatory cytokine expression and the STAT1/3 pathway in canine chronic enteropathy and intestinal T-cell lymphoma

“…8,25 Since canine CE involves various inflammatory cells, such as CD4 + T-cells, CD8 + T-cells, plasma cells, and macrophages, 19 a more detailed understanding of the cytokine interactions between these inflammatory cells is essential for elucidating the pathogenesis of this disease. Previous studies on canine duodenal CE reported decreases in interleukin (IL)-17, IL-13, and IL-33 mRNA expression in German shepherd dogs, 24,45 while others found no significant difference in cytokine mRNA expression patterns between dogs with and without CE. 35,39 Therefore, canine CE is currently considered to be a complex group of diseases involving multiple factors, such as breed, the type of cellular infiltration in the lamina propria, and disease progression.…”