Identification of Differentially Expressed Gpr116 (Adgrf5) Transcript Variants in Mouse Kidney

Adhesion G protein-coupled receptors (aGPCRs) are important and understudied modulators of physiological processes. Previous work suggests that aGPCRs, and Adgrf5 in particular, undergo significant tissue-specific mRNA processing that results in holoreceptors with unique and variable N-terminal structures (Knierim et al. 2019). Recently, it was shown that transcripts of the postsynaptic aGPCR Latrophilin-3 (Lphn3/Adgrl3) undergo physiologically relevant alternative splicing, which determined heterotrimeric signaling through Gαs- or Gα12/13- mediated pathways (Südhof et al. 2024). These results demonstrate that identifying precise, tissue-specific transcript variants is critical to understanding the physiological relevance of aGPCRs. Moreover, these studies highlight the possibility that tissue expression of single aGPCRs is likely comprised of multiple transcript variants. We previously demonstrated that kidney-specific Adgrf5/Gpr116 knockout causes luminal membrane accumulation of V-ATPase in acid-secreting A-type intercalated cells (AICs) in the collecting ducts and a significant reduction in urine pH (Zaidman et al. 2020). Renal Adgrf5 is restricted to two distinct populations of cells: AICs and endothelial cells (ECs). We hypothesized that cell-specific Adgrf5 transcript variants are expressed in renal AICs and ECs, and therefore are activated by distinct mechanisms unique to the cellular microenvironment. We detected and aligned three Adgrf5 exons that undergo differential expression in the kidney: exons 2, 12, and 22. Adgrf5 transcripts in FACS-sorted GFP + ICs do not contain the exon 2 variable region, or the alternative exons 12 and 22, while ECs contain all three. However, EC markers were detected in GFP + ICs, demonstrating some EC contamination in the sorted ICs. Detection of transcripts that do, and do not, contain multiple variable regions suggests expression of multiple mRNAs in specific cells. These data demonstrate that Adgrf5 transcript variants are cell-specific in the kidney. Moreover, the complete repertoire of aGPCRs expressed in the kidney is undefined. We performed single-nucleus RNA sequencing on male and female kidneys. snRNAseq revealed abundant, cell-specific expression of six aGPCRs (Adgrl4, Adgre5, Adgrf1, Adgrf5, Adgrg1, and Adgrg3). Detection of these, as well as 18 other aGPCRs, was confirmed by PCR screening for GAIN/GPS domains on cDNA from whole-kidney lysates. These results reveal the complete set of aGPCRs expressed in the murine kidney. Future studies will focus on determining the physiological roles and tissue-specific variants of these receptors. NIDDK (R00DK127215; Zaidman), UNM Research Allocation Committee, UNM CCC Support Grant NCI P30CA118100, and the Analytical & Translational Genomics Shared Resource This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.