Repression of let-7 by transforming growth factor-β1-induced Lin28 upregulates collagen expression in glomerular mesangial cells under diabetic conditions

Jung Tak Park, Mitsuo Kato, Linda Lanting, Nancy Castro, Bo Young Nam, Mei Wang, Shin-Wook Kang, Rama Natarajan

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Accumulation of mesangial extracellular matrix (ECM) proteins such as collagen type 1-a2 (Col1a2) and collagen type 4-a1 (Col4a1) is a key feature of diabetic nephropathy (DN). Transforming growth factor (TGF)-ß1 plays important roles in ECM accumulation in DN, and evidence shows a mediatory role for microRNAs. In the present study, we found that microRNA let-7 family members (let-7b/c/d/g/i) were downregulated in TGF-ß-treated mouse mesangial cells (MMCs) along with upregulation of Col1a2 and Col4a1. Ectopic expression of let-7b in TGF-ß-treated MMCs attenuated Col1a2 and Col4a1 upregulation. Conversely, let-7b inhibitors increased Col1a2 and Col4a1 levels. Cotransfection of MMCs with mouse Col1a2 or Col4a1 3'-untranslated region luciferase constructs and let-7b inhibitors increased luciferase activity. However, constructs with let-7 target site mutations were unresponsive to TGF-ß. TGF-ß-induced 3'-untranslated region activity was attenuated by let-7b mimics, suggesting that Col1a2 and Col4a1 are direct targets of let-7b. In addition, Lin28b, a negative regulator of let-7 biogenesis, was upregulated in TGF-ß-treated MMCs. Lu-ciferase assays showed that the Lin28b promoter containing the Smad-binding element (SBE) responded to TGF-ß, which was abolished in constructs without SBE. Chromatin immunoprecipitation assays showed TGF-ß-induced enrichment of Smad2/3 at the Lin28b promoter, together suggesting that Lin28b is transcriptionally induced by TGF-ß through SBE. Furthermore, let-7b levels were decreased, whereas Lin28b, Col1a2, and Col4a1 levels were increased, in glom-eruli of diabetic mice compared with nondiabetic control mice, demonstrating the in vivo relevance of this Lin28/let-7/collagen axis. These results identify Lin28 as a new TGF-ß target gene and suggest a novel role for the Lin28/let-7 pathway in controlling TGF-ß-induced collagen accumulation in DN.

Original languageEnglish
Pages (from-to)F1390-F1403
JournalAmerican Journal of Physiology - Renal Physiology
Volume307
Issue number12
DOIs
Publication statusPublished - 2014 Dec 15

Fingerprint

Mesangial Cells
Transforming Growth Factors
Up-Regulation
Collagen
Collagen Type IV
Collagen Type I
Diabetic Nephropathies
3' Untranslated Regions
Luciferases
MicroRNAs
Glomerular Mesangium
Chromatin Immunoprecipitation
Extracellular Matrix Proteins
Extracellular Matrix
Down-Regulation

All Science Journal Classification (ASJC) codes

  • Physiology
  • Urology

Cite this

Park, Jung Tak ; Kato, Mitsuo ; Lanting, Linda ; Castro, Nancy ; Nam, Bo Young ; Wang, Mei ; Kang, Shin-Wook ; Natarajan, Rama. / Repression of let-7 by transforming growth factor-β1-induced Lin28 upregulates collagen expression in glomerular mesangial cells under diabetic conditions. In: American Journal of Physiology - Renal Physiology. 2014 ; Vol. 307, No. 12. pp. F1390-F1403.
@article{a480c3ae2feb437a85200014e322de12,
title = "Repression of let-7 by transforming growth factor-β1-induced Lin28 upregulates collagen expression in glomerular mesangial cells under diabetic conditions",
abstract = "Accumulation of mesangial extracellular matrix (ECM) proteins such as collagen type 1-a2 (Col1a2) and collagen type 4-a1 (Col4a1) is a key feature of diabetic nephropathy (DN). Transforming growth factor (TGF)-{\ss}1 plays important roles in ECM accumulation in DN, and evidence shows a mediatory role for microRNAs. In the present study, we found that microRNA let-7 family members (let-7b/c/d/g/i) were downregulated in TGF-{\ss}-treated mouse mesangial cells (MMCs) along with upregulation of Col1a2 and Col4a1. Ectopic expression of let-7b in TGF-{\ss}-treated MMCs attenuated Col1a2 and Col4a1 upregulation. Conversely, let-7b inhibitors increased Col1a2 and Col4a1 levels. Cotransfection of MMCs with mouse Col1a2 or Col4a1 3'-untranslated region luciferase constructs and let-7b inhibitors increased luciferase activity. However, constructs with let-7 target site mutations were unresponsive to TGF-{\ss}. TGF-{\ss}-induced 3'-untranslated region activity was attenuated by let-7b mimics, suggesting that Col1a2 and Col4a1 are direct targets of let-7b. In addition, Lin28b, a negative regulator of let-7 biogenesis, was upregulated in TGF-{\ss}-treated MMCs. Lu-ciferase assays showed that the Lin28b promoter containing the Smad-binding element (SBE) responded to TGF-{\ss}, which was abolished in constructs without SBE. Chromatin immunoprecipitation assays showed TGF-{\ss}-induced enrichment of Smad2/3 at the Lin28b promoter, together suggesting that Lin28b is transcriptionally induced by TGF-{\ss} through SBE. Furthermore, let-7b levels were decreased, whereas Lin28b, Col1a2, and Col4a1 levels were increased, in glom-eruli of diabetic mice compared with nondiabetic control mice, demonstrating the in vivo relevance of this Lin28/let-7/collagen axis. These results identify Lin28 as a new TGF-{\ss} target gene and suggest a novel role for the Lin28/let-7 pathway in controlling TGF-{\ss}-induced collagen accumulation in DN.",
author = "Park, {Jung Tak} and Mitsuo Kato and Linda Lanting and Nancy Castro and Nam, {Bo Young} and Mei Wang and Shin-Wook Kang and Rama Natarajan",
year = "2014",
month = "12",
day = "15",
doi = "10.1152/ajprenal.00458.2014",
language = "English",
volume = "307",
pages = "F1390--F1403",
journal = "American Journal of Physiology - Renal Physiology",
issn = "1931-857X",
publisher = "American Physiological Society",
number = "12",

}

Repression of let-7 by transforming growth factor-β1-induced Lin28 upregulates collagen expression in glomerular mesangial cells under diabetic conditions. / Park, Jung Tak; Kato, Mitsuo; Lanting, Linda; Castro, Nancy; Nam, Bo Young; Wang, Mei; Kang, Shin-Wook; Natarajan, Rama.

In: American Journal of Physiology - Renal Physiology, Vol. 307, No. 12, 15.12.2014, p. F1390-F1403.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Repression of let-7 by transforming growth factor-β1-induced Lin28 upregulates collagen expression in glomerular mesangial cells under diabetic conditions

AU - Park, Jung Tak

AU - Kato, Mitsuo

AU - Lanting, Linda

AU - Castro, Nancy

AU - Nam, Bo Young

AU - Wang, Mei

AU - Kang, Shin-Wook

AU - Natarajan, Rama

PY - 2014/12/15

Y1 - 2014/12/15

N2 - Accumulation of mesangial extracellular matrix (ECM) proteins such as collagen type 1-a2 (Col1a2) and collagen type 4-a1 (Col4a1) is a key feature of diabetic nephropathy (DN). Transforming growth factor (TGF)-ß1 plays important roles in ECM accumulation in DN, and evidence shows a mediatory role for microRNAs. In the present study, we found that microRNA let-7 family members (let-7b/c/d/g/i) were downregulated in TGF-ß-treated mouse mesangial cells (MMCs) along with upregulation of Col1a2 and Col4a1. Ectopic expression of let-7b in TGF-ß-treated MMCs attenuated Col1a2 and Col4a1 upregulation. Conversely, let-7b inhibitors increased Col1a2 and Col4a1 levels. Cotransfection of MMCs with mouse Col1a2 or Col4a1 3'-untranslated region luciferase constructs and let-7b inhibitors increased luciferase activity. However, constructs with let-7 target site mutations were unresponsive to TGF-ß. TGF-ß-induced 3'-untranslated region activity was attenuated by let-7b mimics, suggesting that Col1a2 and Col4a1 are direct targets of let-7b. In addition, Lin28b, a negative regulator of let-7 biogenesis, was upregulated in TGF-ß-treated MMCs. Lu-ciferase assays showed that the Lin28b promoter containing the Smad-binding element (SBE) responded to TGF-ß, which was abolished in constructs without SBE. Chromatin immunoprecipitation assays showed TGF-ß-induced enrichment of Smad2/3 at the Lin28b promoter, together suggesting that Lin28b is transcriptionally induced by TGF-ß through SBE. Furthermore, let-7b levels were decreased, whereas Lin28b, Col1a2, and Col4a1 levels were increased, in glom-eruli of diabetic mice compared with nondiabetic control mice, demonstrating the in vivo relevance of this Lin28/let-7/collagen axis. These results identify Lin28 as a new TGF-ß target gene and suggest a novel role for the Lin28/let-7 pathway in controlling TGF-ß-induced collagen accumulation in DN.

AB - Accumulation of mesangial extracellular matrix (ECM) proteins such as collagen type 1-a2 (Col1a2) and collagen type 4-a1 (Col4a1) is a key feature of diabetic nephropathy (DN). Transforming growth factor (TGF)-ß1 plays important roles in ECM accumulation in DN, and evidence shows a mediatory role for microRNAs. In the present study, we found that microRNA let-7 family members (let-7b/c/d/g/i) were downregulated in TGF-ß-treated mouse mesangial cells (MMCs) along with upregulation of Col1a2 and Col4a1. Ectopic expression of let-7b in TGF-ß-treated MMCs attenuated Col1a2 and Col4a1 upregulation. Conversely, let-7b inhibitors increased Col1a2 and Col4a1 levels. Cotransfection of MMCs with mouse Col1a2 or Col4a1 3'-untranslated region luciferase constructs and let-7b inhibitors increased luciferase activity. However, constructs with let-7 target site mutations were unresponsive to TGF-ß. TGF-ß-induced 3'-untranslated region activity was attenuated by let-7b mimics, suggesting that Col1a2 and Col4a1 are direct targets of let-7b. In addition, Lin28b, a negative regulator of let-7 biogenesis, was upregulated in TGF-ß-treated MMCs. Lu-ciferase assays showed that the Lin28b promoter containing the Smad-binding element (SBE) responded to TGF-ß, which was abolished in constructs without SBE. Chromatin immunoprecipitation assays showed TGF-ß-induced enrichment of Smad2/3 at the Lin28b promoter, together suggesting that Lin28b is transcriptionally induced by TGF-ß through SBE. Furthermore, let-7b levels were decreased, whereas Lin28b, Col1a2, and Col4a1 levels were increased, in glom-eruli of diabetic mice compared with nondiabetic control mice, demonstrating the in vivo relevance of this Lin28/let-7/collagen axis. These results identify Lin28 as a new TGF-ß target gene and suggest a novel role for the Lin28/let-7 pathway in controlling TGF-ß-induced collagen accumulation in DN.

UR - http://www.scopus.com/inward/record.url?scp=84918834795&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84918834795&partnerID=8YFLogxK

U2 - 10.1152/ajprenal.00458.2014

DO - 10.1152/ajprenal.00458.2014

M3 - Article

VL - 307

SP - F1390-F1403

JO - American Journal of Physiology - Renal Physiology

JF - American Journal of Physiology - Renal Physiology

SN - 1931-857X

IS - 12

ER -