Beclin 1 prevents ISG15-mediated cytokine storms to secure fetal hematopoiesis and survival
Wen Wei, Xueqin Gao, Jiawei Qian, Lei Li, Chen Zhao, Li Xu, Yanfei Zhu, Zhenzhen Liu, Nengrong Liu, Xueqing Wang, Zhicong Jin, Bowen Liu, Lan Xu, Jin Dong, Suping Zhang, Jiarong Wang, Yumu Zhang, Yao Yu, Zhanjun Yan, Yanjun Yang, Jie Lu, Yixuan Fang, Na Yuan, Jianrong Wang
Wen Wei, Xueqin Gao, Jiawei Qian, Lei Li, Chen Zhao, Li Xu, Yanfei Zhu, Zhenzhen Liu, Nengrong Liu, Xueqing Wang, Zhicong Jin, Bowen Liu, Lan Xu, Jin Dong, Suping Zhang, Jiarong Wang, Yumu Zhang, Yao Yu, Zhanjun Yan, Yanjun Yang, Jie Lu, Yixuan Fang, Na Yuan, Jianrong Wang
View: Text | PDF
Research Article Hematology Immunology

Beclin 1 prevents ISG15-mediated cytokine storms to secure fetal hematopoiesis and survival

Abstract

Proper control of inflammatory responses is essential for embryonic development, but the underlying mechanism is poorly understood. Here, we show that under physiological conditions, inactivation of ISG15, an inflammation amplifier, is associated with the interaction of Beclin 1 (Becn1), via its evolutionarily conserved domain, with STAT3 in the major fetal hematopoietic organ of mice. Conditional loss of Becn1 caused sequential dysfunction and exhaustion of fetal liver hematopoietic stem cells, leading to lethal inflammatory cell–biased hematopoiesis in the fetus. Molecularly, the absence of Becn1 resulted in the release of STAT3 from Becn1 tethering and subsequent phosphorylation and translocation to the nucleus, which in turn directly activated the transcription of ISG15 in fetal liver hematopoietic cells, coupled with increased ISGylation and production of inflammatory cytokines, whereas inactivating STAT3 reduced ISG15 transcription and inflammation but improved hematopoiesis potential, and further silencing ISG15 mitigated the above collapse in the Becn1-null hematopoietic lineage. The Becn1/STAT3/ISG15 axis remains functional in autophagy-disrupted fetal hematopoietic organs. These results suggest that Becn1, in an autophagy-independent manner, secures hematopoiesis and survival of the fetus by directly inhibiting STAT3/ISG15 activation to prevent cytokine storms. Our findings highlight a previously undocumented role of Becn1 in governing ISG15 to safeguard the fetus.

Authors

Wen Wei, Xueqin Gao, Jiawei Qian, Lei Li, Chen Zhao, Li Xu, Yanfei Zhu, Zhenzhen Liu, Nengrong Liu, Xueqing Wang, Zhicong Jin, Bowen Liu, Lan Xu, Jin Dong, Suping Zhang, Jiarong Wang, Yumu Zhang, Yao Yu, Zhanjun Yan, Yanjun Yang, Jie Lu, Yixuan Fang, Na Yuan, Jianrong Wang

×

Figure 7

Inhibition of STAT3 activity rescues colony-forming ability and reduces Isg15 transcription in Becn1-deleted fetal liver hematopoietic cells, and Becn1 deletion results in p-STAT3 binding to the Isg15 gene.

Options: View larger image (or click on image) Download as PowerPoint
Inhibition of STAT3 activity rescues colony-forming ability and reduces ...
(A) Schematic plan for CFU assay of STAT3 inhibitor–treated Lin– cells from E12.5 FLCs. (B) Pharmacological inhibition of STAT3 reversed the colony formation capacity of Becn1–/– liver hematopoietic cells. Left: Representative images. Right: Statistical results of colonies from E12.5 fetal liver Lin– cells treated with a STAT3 inhibitor (n = 4). Scale bars: 100 μm. (C) Real-time qPCR analysis of ISG15 expression in E12.5 Lin– cells after STAT3 inhibitor treatment. n = 4–5. (D) Profile plots of p-STAT3 enrichment at the transcription start site (TSS) region based on ChIP-Seq of E14.5 Becn1–/– fetal livers (n = 2). (E) Peak center read density heatmap of ChIP-Seq signals for the binding of p-STAT3 in E14.5 FLCs. (F) p-STAT3 interacted with the Isg15 gene according to the Integrative Genomics Viewer (IGV). *P < 0.05; **P < 0.01. Unpaired 2-tailed Student’s t test (B); 1-way ANOVA (Tukey’s multiple-comparison test) (C). Data represent the mean ± SEM.