Inhibition of the ERK1/2-mTORC1 axis ameliorates proteinuria and the fibrogenic action of transforming growth factor-β in Adriamycin-induced glomerulosclerosis

Ranjan Das, Soo Jin Kim, Nhung Thi Nguyen, Hyeong Ju Kwon, Seung Kuy Cha, Kyu Sang Park

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


Transforming growth factor-β (TGF-β) plays crucial roles in the development of focal segmental glomerulosclerosis, but key molecular pathways remain unknown. Here, we identified the regulation of mammalian target of rapamycin complex1 (mTORC1) by TGF-β via ERK1/2 in the Adriamycin-induced murine model of focal segmental glomerulosclerosis. Adriamycin administration elicited early activation of TGF-β-ERK1/2-mTORC1 in podocytes, which persisted at later stages of albuminuria and glomerulosclerosis. Phosphorylation of the TGF-β receptor-I (TGF-βRI), Smad3, ERK1/2 and ribosomal protein S6 were evident in the glomeruli of adriamycin-treated mice. Targeting TGFβ-RI and mTORC1 with pharmacological inhibitors suppressed TGF-β signaling in glomeruli and significantly reduced albuminuria, glomerulosclerosis, protein levels of collagen 4α3, plasminogen activator inhibitor-1, and vimentin and restored mRNA levels of podocyte markers. Low dose US Food and Drug Administration (FDA)-approved MEK/ERK inhibitor trametinib/GSK1120212 blunted TGF-β1–induced mTORC1 activation in podocytes, ameliorated up-regulation of TGF-β, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, fibronectin and α-smooth muscle actin and prevented albuminuria and glomerulosclerosis with improved serum albumin. In cultured podocytes, this pathway was found to be associated with translation of fibrogenic collagen 4α3 and plasminogen activator inhibitor-1, without influencing their transcription. Notably, rapamycin suppressed upstream p-TGF-βRI, p-Smad3 and p-ERK1/2, and trametinib down-regulated upstream p-Smad3 in ex vivo and in vivo studies, indicating that harmful paracrine signaling among glomerular cells amplified the TGF-β–ERK1/2–mTORC1 axis by forming a positive feedback loop. Thus, an accentuated TGF-β–ERK1/2–mTORC1 pathway is suggested as a central upstream mediator to develop proteinuria and glomerulosclerosis. Hence, preventing activation of this vicious loop by trametinib may offer a new therapeutic strategy for glomerular disease treatment.

Original languageEnglish
Pages (from-to)927-941
Number of pages15
JournalKidney International
Issue number4
Publication statusPublished - 2019 Oct

Bibliographical note

Funding Information:
We are thankful to Prof. Jochen Reiser (Rush University, Chicago, IL) for kindly providing mouse immortalized podocytes. This work was supported by the Medical Research Center Program, Ministry of Science, ICT ( 2017R1A5A2015369 ), Myung Sun Kim Memorial Foundation (2016) , and Yonsei University Future-leading Research Initiative (2017) , Korea.

Publisher Copyright:
© 2019 International Society of Nephrology

All Science Journal Classification (ASJC) codes

  • Nephrology


Dive into the research topics of 'Inhibition of the ERK1/2-mTORC1 axis ameliorates proteinuria and the fibrogenic action of transforming growth factor-β in Adriamycin-induced glomerulosclerosis'. Together they form a unique fingerprint.

Cite this