TGR5 expression in normal kidney and renal neoplasms

Area of Science:

• Nephrology
• Oncology
• Molecular Biology

Background:

• The G protein-coupled bile acid receptor (TGR5) is a cell surface receptor involved in cAMP production and epithelial-mesenchymal transition.
• TGR5 is expressed in various tissues, including the kidney, but its expression patterns in normal renal tissue and neoplasms are not well-defined.

Purpose of the Study:

• To investigate TGR5 expression in benign renal tissue and renal neoplasms.
• To evaluate the potential utility of TGR5 as a diagnostic marker for renal tumors.

Main Methods:

• Immunohistochemistry was used to examine TGR5 protein expression in 61 renal cortical neoplasms.
• Real-time PCR was employed to measure TGR5 mRNA levels.

Main Results:

• TGR5 was strongly expressed in collecting ducts, distal convoluted tubules, and the thin loop of Henle in normal kidney tissue.
• A significant decrease in TGR5 protein and mRNA expression was observed in clear cell renal cell carcinomas (RCCs) (92% negative).
• Papillary RCCs, chromophobe RCCs, oncocytomas, and urothelial carcinomas of the renal pelvis showed varying degrees of TGR5 expression, generally higher than in clear cell RCCs.

Conclusions:

• TGR5 exhibits distinct expression patterns in normal renal tubules.
• Downregulation of TGR5 in clear cell RCCs suggests its potential as a biomarker for differentiating these tumors from other renal neoplasms.