Compared gene expression between kidney and renal pelvis

Tertiary lymphoid tissues (TLTs) are formed in systemic organs manifesting chronic inflammation. Herein, we found that the renal pelvis (RP) could form urinary tract-associated lymphoid tissues (UTALTs) in a TLT-formation manner in humans and mice with chronic kidney disease (CKD), regardless of infectious pyelonephritis. Our results demonstrated that urine is crucial for UTALT development. Urine leak from the lumen into the parenchyma of the RP through an altered transitional epithelium (TE) barrier, stimulated RP stromal cells immunologically and attracted immune cells via cytokine and chemokine production. Pathophysiological crosstalk was observed between UTALT development and tubulointerstitial lesions and TLT formation in the kidney. The kidney and renal pelvis were isolated from 7 MRL/MpJ (control) and 10 MRL/MpJ-Faslpr/lpr (disease model). For kidney and renal pelvis, the extraRNA from MRL/MpJ (n = 7) and MRL/lpr (n = 10) was pooled as one sample for each group.