The ILEI/LIFR complex induces EMT via the Akt and ERK pathways in renal interstitial fibrosis

J Transl Med. 2022 Jan 29;20(1):54. doi: 10.1186/s12967-022-03265-2.

Abstract

Background: Chronic kidney disease (CKD) is characterized by high morbidity and mortality and is difficult to cure. Renal interstitial fibrosis (RIF) is a major determinant of, and commonly occurs within, CKD progression. Epithelial mesenchymal transition (EMT) has been identified as a crucial process in triggering renal interstitial fibrosis (RIF). Interleukin-like EMT inducer (ILEI) is an important promotor of EMT; this study aims to elucidate the mechanisms involved.

Methods: Male C57BL6/J mouse were randomly divided into 6 groups: sham (n = 10), sham with negative control (NC) shRNA (sham + NC, n = 10), sham with ILEI shRNA (sham + shILEI, n = 10), unilateral ureteral obstruction (UUO, n = 10), UUO with NC (UUO + NC, n = 10) and UUO with ILEI shRNA (UUO + shILEI, n = 10). Hematoxylin and eosin (H&E), Masson, and immunohistochemical (IHC) staining and western blotting (WB) were performed on murine kidney tissue to identify the function and mechanism of ILEI in RIF. In vitro, ILEI was overexpressed to induce EMT in HK2 cells and analyzed via transwell, WB, real-time PCR, and co-immunoprecipitation. Finally, tissue from 12 pediatric CKD patients (seven with RIF and five without RIF) were studied with H&E, Masson, and IHC staining.

Results: Our in vitro model revealed that ILEI facilitates RIF in the UUO model via the Akt and ERK pathways. Further experiments in vivo and in vitro revealed that ILEI promotes renal tubular EMT by binding and activating leukemia inhibitory factor receptor (LIFR), in which phosphorylation of Akt and ERK is involved. We further find markedly increased expression levels of ILEI and LIFR in kidneys from pediatric CKD patients with RIF.

Conclusion: Our results indicate that ILEI may be a useful biomarker for renal fibrosis and a potential therapeutic target for modulating RIF.

Keywords: Epithelial-to-mesenchymal transition (EMT); Interleukin-like epithelial-to-mesenchymal transition inducer (ILEI); Leukemia inhibitory factor receptor (LIFR); Renal interstitial fibrosis (RIF).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Child
  • Disease Models, Animal
  • Epithelial-Mesenchymal Transition
  • Fibrosis
  • Humans
  • Kidney Diseases* / metabolism
  • Leukemia Inhibitory Factor Receptor alpha Subunit / metabolism
  • MAP Kinase Signaling System
  • Male
  • Mice
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptors, OSM-LIF / metabolism
  • Renal Insufficiency, Chronic*
  • Transforming Growth Factor beta1 / metabolism

Substances

  • LIFR protein, human
  • Leukemia Inhibitory Factor Receptor alpha Subunit
  • Receptors, OSM-LIF
  • Transforming Growth Factor beta1
  • Proto-Oncogene Proteins c-akt