Dr. Wang has developed an in vivo shRNA screening approach to identify a differentiation checkpoint limiting hematopoietic stem cell function. We conducted an in vivo short hairpin RNA (shRNA) screening to search for the checkpoints induced by dysfunctional telomere. After analyzing deep sequencing data, basic leucine zipper transcription factor, ATF-like (Batf) was highly selected in mTerc-/- G3 group. Knockdown of Batf rescues the self-renewal capacity of HSCs in response to DNA damage including telomere shortening and ioizing radiation. Upon DNA damage or physiological aging, Batf expression in HSCs is up-regulatd, which is dependent on GCSF/Stat3 signaling. Forced Batf limits HSCs function. Moreover, DNA damage induces differentiation of Ly-HSCs into progenitors, which is mediating by Batf. In addition, disrupt of Batf blocks the differentiation of Ly-HSCs into lymphoid progenitors. The finding points out that differentiation checkpoint activation could be another layer to protect DNA damage accumulation in HSCs, furthermore protecting transformation of damaged HSCs into cancer initiating cells.

1)HSC accumulates DNA damage with aging because most of HSCs are in quiescent stage. DNA damage inducing differentiation of HSCs plays an important manner to prevent damage accumulation. But, some HSCs can bypass differentiation signaling to accumulate DNA damage. What is the molecular signaling activated to prevent the proliferation of severely damaged HSCs is not delineated yet. In our recent study (Wang et al. Blood, 2014), we identified that senescence and apoptosis pathways collaborate to prevent the proliferation of severely damaged HSCs. Once HSCs accumulate high level damage, senescence pathway (p16) is activated to arrest HSCs in quiescent, even though upon stimulation. For the HSCs with low level damage, apoptosis signaling (caspase 3, puma) is activated to render damaged HSCs into apoptosis, thus prohibiting the transformation of damaged HSCs into cancer cells.

2)Aging associated impairments in hemato-lymphopoiesis are associated with DNA damage accumulation and reduced maintenance of lymphoid-biased hematopoietic stem cells (Ly-biased HSCs). We identifies Period circadian protein 2 (Per2) as a critical factor limiting the maintenance of HSCs in response to DNA damage and aging. Under these conditions, Per2 is activated predominantly in Ly-biased HSCs and stimulates DNA damage signaling and p53-dependent apoptosis in hematopoietic cells. Per2 deletion ameliorates replications stress and DNA damage responses in hematopoietic cells thereby improving the maintenance of Ly-biased HSCs, lymphopoiesis, and immune function in aging mice without increasing the accumulation of DNA damage. Per2 deficient mice retain Batf/p53-dependent induction of differentiation of HSCs in response to DNA damage and exhibit an elongated lifespan without increases in cancer. Together, these results identify Per2 as a negative regulator of Ly-biased HSCs and immune functions in response to DNA damage and aging.

1. Hanqing He, Panglian Xu , Xiaofei Zhang , Min Liao , Qiongye Dong , Tingting Cong , Baixue Tang , Xiuxiu Yang , Maoqing Ye , Ying-Jun Chang , Weihua Liu, Xiaowo Wang, Zhenyu Ju, Jianwei Wang#. Aging-induced IL27Ra Signaling Impairs Hematopoietic Stem Cells. BLOOD. 2020;136(2):183-198.

2. Xiuxiu Yang, Liang Ge, Jianwei Wang#. BECN1 modulates hematopoietic stem cells by targeting Caspase-3-GSDME-mediated pyroptosis. BLOOD Science. 2020, in press.

3. Hanqing He, Yuqian Wang, Jianwei Wang#. ALKBH3 is dispensable in maintaining hematopoietic stem cells but forced ALKBH3 rectified the differentiation skewing of aged hematopoietic stem cells. BLOOD Science. 2020;2(3):89-99.

4. Min Liao, Jianwei Wang#. Tcf12 balances the reconstitution and differentiation capacity of hematopoietic stem cell. BLOOD Science. 2020, in press.

5. Xiuxiu Yang, Tingting Cong, Hanqing He, Jianwei Wang#. GSDME maintains Hematopoietic Stem Cells by Balancing Pyroptosis and Apoptosis. BLOOD Science. 2020, in press.

6. Min Liao & Jianwei Wang#. Mechanisms of hematopoietic stem cell ageing and targets for hematopoietic tumour prevention. Adv. Exp. Med. Biol. 2018;1086:117-140.

7. Jianwei Wang, Yohei Morita, Bing Han and Karl Lenhard Rudolph. Per2 induction limits lymphoid-biased hematopoietic stem cells and immune function in the context of DNA damage and aging. (Nat Cell Biol. 2016 May;18(5):480-90)

8. Jianwei Wang, Xin Lu, Vadim Sakk, Christoph A. Klein, and Karl Lenhard Rudolph. Senescence and apoptosis block hematopoietic activation of quiescent hematopoietic stem cells with short telomeres. Blood. 2014 Nov 20;124(22):3237-40.

9. Tobias Sperka*, Jianwei Wang* & K. Lenhard Rudolph. DNA damage checkpoints in stem cells, aging and cancer. Nature Reviews Molecular Cell Biology. 2012; 23:579-590. (*Equal contribution)

10. Jianwei Wang, Qian Sun, Yohei Morita, Hong Jiang,,, K. Lenhard Rudolph. A differentiation checkpoint limiting hematopoietic stem cell self-renewal in response to DNA damage. Cell. 2012;148(5):1001-1014.

11. Jianwei Wang, Hartmut Geiger, K. Lenhard Rudolph. Immunoaging induced by hematopoietic stem cell aging. Current Opinion in Immunology. 2011;23(4):532-536.

12. Jianwei Wang*, Hu Wang*, Jingzhou Chen, Xiaojian Wang, Kai Sun, Yibo Wang, Jizheng, Hui Rutai. GADD45B Inhibits MKK7-induced Cardiac Hypertrophy and is Associated with Hypertropic Cardiomyopathy. Biochem Biophys Res Commun. 2008; 372(4):623-628. (*Equal contribution)

13. Jianwei Wang, Fu Chunyan, Hui Rutai. The Potential Role of GADD45-βGene in the Development of Hypertrophic Cardiomyopathy. Molecular Cardiology of China. 2005;5(4):616-618.

14. Zhangfa Song, Jianwei Wang, Luis Miguel Guachalla, Grzegorz Terszowski, Hans-Reimer Rodewald, Zhenyu Ju, and K. Lenhard Rudolph. Alterations of the systemic environment are the primary cause of impaired B and T lymphopoiesis in telomere-dysfunctional mice. BLOOD. 2010;115(8):1481148-9.

15. Hong Jiang, Eric Schiffer, Zhangfa Song, Jianwei Wang, Petra Zürbig, Kathrin Thedieck, Suzette Moes, Heike Bantel, Nadja Saal, Justyna Jantos, Meiken Brecht, Paul Jenö, Michael N. Hall, Klaus Hager, Michael P. Manns, Hartmut Hecker, Arnold Ganser, Konstanze Döhner, Andrzej Bartke, Christoph Meissner, Harald Mischak, Zhenyu Ju, and K. Lenhard Rudolph. Proteins induced by telomere dysfunction and DNA damage represent biomarkers of human aging and disease. Proc Natl Acad Sci U S A. 2008;105(32):11299–04.

16. Shuxia Wang, Yubao Zou, Chunyan Fu, Xiqi Xu, Jizheng Wang, Lei Song, Hu Wang, Jingzhou Chen, Jianwei Wang, Tujun Huan, Rutai Hui. Worse prognosis with gene mutations of beta-myosin heavy chain than myosin-binding protein C in Chinese patients with hypertrophic cardiomyopathy. Clin Cardiol. 2008;31(3):114-8.

17. Yibo Wang, Weili Zhang, Yuhui Zhang, Yuejin Yang, Lizhong Sun, Shengshou Hu, Jilin Chen，Channa Zhang, Yi Zheng, Yisong Zhen, Kai Sun, Chunyan Fu, Tao Yang, Jianwei Wang, Jing Sun, Haiying Wu, Wayne C Glasgow, and Rutai Hui. VKORC1 Haplotypes are Associated with Arterial Vascular Diseases (Stroke, Coronary Heart Disease and Aortic Dissection). Circulation. 2006; 113(12):1615-21.