Case-inspired exploration of renin mutations in autosomal dominant tubulointerstitial kidney disease: not all paths lead to the endoplasmic reticulum

Joanna Niedbalska-Tarnowska; Anna Jakubowska; Michał Majkowski; Michalina Pęcherz; Anna Medyńska; Robert Mroczek; Katarzyna Kiliś-Pstrusińska; Małgorzata Cebrat; Agnieszka Łaszkiewicz

doi:10.1007/s00467-024-06350-4

Case-inspired exploration of renin mutations in autosomal dominant tubulointerstitial kidney disease: not all paths lead to the endoplasmic reticulum

Pediatr Nephrol. 2024 Mar 23. doi: 10.1007/s00467-024-06350-4. Online ahead of print.

Authors

Joanna Niedbalska-Tarnowska¹, Anna Jakubowska², Michał Majkowski³, Michalina Pęcherz¹, Anna Medyńska², Robert Mroczek¹, Katarzyna Kiliś-Pstrusińska², Małgorzata Cebrat¹, Agnieszka Łaszkiewicz⁴

Affiliations

¹ Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Laboratory of Molecular and Cellular Immunology, Wroclaw, Poland.
² Department of Pediatric Nephrology, Wroclaw Medical University, Wroclaw, Poland.
³ Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland.
⁴ Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Laboratory of Molecular and Cellular Immunology, Wroclaw, Poland. agnieszka.laszkiewicz@hirszfeld.pl.

PMID: 38520530
DOI: 10.1007/s00467-024-06350-4

Abstract

Background: Autosomal dominant tubulointerstitial kidney disease (ADTKD) results from mutations in various genes, including REN, UMOD, MUC1, and HNF1B. ADTKD due to REN mutations (ADTKD-REN) is often characterized as a proteinopathy that triggers the endoplasmic reticulum stress (ERS) cascade, potentially sharing similarities with ADTKD-UMOD and ADTKD-MUC1 at the cellular level. This study, inspired by a patient harboring a W17R mutation, investigates ERS activation by this mutation alongside two other renin variants, W10R and L381P.

Methods: We established stable cell lines expressing both wild-type and mutated renin forms (W17R, W10R, and L381P). Using luciferase reporter assays, RT-qPCR, and confocal microscopy, we evaluated ERS activation, determined the cellular localization of the renin variants, and characterized the mitochondrial network in the W17R line.

Results: The L381P line exhibited ERS activation, including transcriptional upregulation of MANF and CRELD2. No ERS activation was observed in the W17R line, while the W10R line exhibited intermediate characteristics. Notably, the W17R variant was misrouted to the mitochondria resulting in changes of the mitochondrial network organisation.

Conclusions: ERS activation is not a universal response to different renin mutations in ADTKD-REN. The pathogenesis of the W17R mutation may involve mitochondrial dysfunction rather than the ER pathway, albeit further research is needed to substantiate this hypothesis fully. Testing CRELD2 and MANF as targeted therapy markers for a specific subgroup of ADTKD-REN patients is recommended. Additionally, fludrocortisone treatment has shown efficacy in stabilizing the renal function of our patient over a four-year period without significant side effects.

Keywords: ADTKD-REN; ADTKD-UMOD; Autosomal dominant tubulointerstitial kidney disease; CRELD2; MANF; Mitochondrially inherited tubulointerstitial kidney disease (MITKD); Renin.