Proximal tubule ATR regulates DNA repair to prevent maladaptive renal injury responses
Seiji Kishi, … , Ryuji Morizane, Joseph V. Bonventre
Seiji Kishi, … , Ryuji Morizane, Joseph V. Bonventre
Published October 7, 2019
Citation Information: J Clin Invest. 2019;129(11):4797-4816. https://doi.org/10.1172/JCI122313.
View: Text | PDF
Research Article Nephrology

Proximal tubule ATR regulates DNA repair to prevent maladaptive renal injury responses

Abstract

Maladaptive proximal tubule (PT) repair has been implicated in kidney fibrosis through induction of cell-cycle arrest at G2/M. We explored the relative importance of the PT DNA damage response (DDR) in kidney fibrosis by genetically inactivating ataxia telangiectasia and Rad3-related (ATR), which is a sensor and upstream initiator of the DDR. In human chronic kidney disease, ATR expression inversely correlates with DNA damage. ATR was upregulated in approximately 70% of Lotus tetragonolobus lectin–positive (LTL+) PT cells in cisplatin-exposed human kidney organoids. Inhibition of ATR resulted in greater PT cell injury in organoids and cultured PT cells. PT-specific Atr-knockout (ATRRPTC–/–) mice exhibited greater kidney function impairment, DNA damage, and fibrosis than did WT mice in response to kidney injury induced by either cisplatin, bilateral ischemia-reperfusion, or unilateral ureteral obstruction. ATRRPTC–/– mice had more cells in the G2/M phase after injury than did WT mice after similar treatments. In conclusion, PT ATR activation is a key component of the DDR, which confers a protective effect mitigating the maladaptive repair and consequent fibrosis that follow kidney injury.

Authors

Seiji Kishi, Craig R. Brooks, Kensei Taguchi, Takaharu Ichimura, Yutaro Mori, Akinwande Akinfolarin, Navin Gupta, Pierre Galichon, Bertha C. Elias, Tomohisa Suzuki, Qian Wang, Leslie Gewin, Ryuji Morizane, Joseph V. Bonventre

×

Figure 10

Atr deletion increases the formation of TASCCs in RPTECs in human kidney organoids exposed to cisplatin and mice after UUO.

Options: View larger image (or click on image) Download as PowerPoint
Atr deletion increases the formation of TASCCs in RPTECs in human kidne...
(A) Representative images of H9 cell–derived day-64 organoids treated with either cisplatin (5 μM for 24 hours and analyzed 24 hours or 120 hours after cisplatin removal [long term]) or vehicle (DMSO). Sections of the organoids were stained for LC3, mTOR, and DAPI. Arrowheads point to TASCCs. The right 6 panels are enlarged images of the boxed areas. n = 2× 8–11 HPF in each treatment group. Scale bars: 10 μm. (B) Super-resolution SIM images of kidney tissue from ATRCtrl and ATRRPTC–/– mice 7 days after UUO, stained for LC3, mTOR, and DAPI. Shown are representative single-plane and 3D reconstruction images. Scale bars: 2 μm (all panels). Dot plot shows the quantification of TASCCs. ATRCtrl (n = 4), ATRRPTC–/– (n = 4). Data are presented as the mean ± SEM. Statistical significance was determined by 1-way ANOVA with Tukey’s post hoc test (A) and 2-tailed, unpaired t test (B). **P < 0.01.