RNAi screens identify HES4 as a regulator of redox balance supporting pyrimidine synthesis and tumor growth

Jing He; Aoxue Wang; Qin Zhao; Yejun Zou; Zhuo Zhang; Nannan Sha; Guofang Hou; Bei Zhou; Yi Yang; Tao Chen; Yuzheng Zhao; Yuhui Jiang

doi:10.1038/s41594-024-01309-3

RNAi screens identify HES4 as a regulator of redox balance supporting pyrimidine synthesis and tumor growth

Nat Struct Mol Biol. 2024 May 20. doi: 10.1038/s41594-024-01309-3. Online ahead of print.

Authors

Jing He^#¹, Aoxue Wang^#^{2

3}, Qin Zhao¹, Yejun Zou^{2

3

4}, Zhuo Zhang^{2

3}, Nannan Sha¹, Guofang Hou¹, Bei Zhou¹, Yi Yang², Tao Chen⁵, Yuzheng Zhao^{6

7}, Yuhui Jiang⁸

Affiliations

¹ Department of Liver Surgery and Shanghai Cancer Institute, State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
² Optogenetics & Synthetic Biology Interdisciplinary Research Center, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai, China.
³ Research Unit of New Techniques for Live-Cell Metabolic Imaging, Chinese Academy of Medical Sciences, Beijing, China.
⁴ Department of Gynecology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai, China.
⁵ Endoscopy Center, Department of Gastroenterology, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
⁶ Optogenetics & Synthetic Biology Interdisciplinary Research Center, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, State Key Laboratory of Bioreactor Engineering, School of Pharmacy, East China University of Science and Technology, Shanghai, China. yuzhengzhao@ecust.edu.cn.
⁷ Research Unit of New Techniques for Live-Cell Metabolic Imaging, Chinese Academy of Medical Sciences, Beijing, China. yuzhengzhao@ecust.edu.cn.
⁸ Department of Liver Surgery and Shanghai Cancer Institute, State Key Laboratory of Systems Medicine for Cancer, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. yhjiang@shsmu.edu.cn.

^# Contributed equally.

PMID: 38769389
DOI: 10.1038/s41594-024-01309-3

Abstract

NADH/NAD⁺ redox balance is pivotal for cellular metabolism. Systematic identification of NAD(H) redox regulators, although currently lacking, would help uncover unknown effectors critically implicated in the coordination of growth metabolism. In this study, we performed a genome-scale RNA interference (RNAi) screen to globally survey the genes involved in redox modulation and identified the HES family bHLH transcription factor HES4 as a negative regulator of NADH/NAD⁺ ratio. Functionally, HES4 is shown to be crucial for maintaining mitochondrial electron transport chain (ETC) activity and pyrimidine synthesis. More specifically, HES4 directly represses transcription of SLC44A2 and SDS, thereby inhibiting mitochondrial choline oxidation and cytosolic serine deamination, respectively, which, in turn, ensures coenzyme Q reduction capacity for DHODH-mediated UMP synthesis and serine-derived dTMP production. Accordingly, inhibition of choline oxidation preserves mitochondrial serine catabolism and ETC-coupled redox balance. Furthermore, HES4 protein stability is enhanced under EGFR activation, and increased HES4 levels facilitate EGFR-driven tumor growth and predict poor prognosis of lung adenocarcinoma. These findings illustrate an unidentified mechanism, underlying pyrimidine biosynthesis in the intersection between serine and choline catabolism, and underscore the physiological importance of HES4 in tumor metabolism.