Persistent DNA damage–induced NLRP12 improves hematopoietic stem cell function
Qiqi Lin, Limei Wu, Zhilin Ma, Fabliha Ahmed Chowdhury,1, Habibul Hasan Mazumder, Wei Du
Qiqi Lin, Limei Wu, Zhilin Ma, Fabliha Ahmed Chowdhury,1, Habibul Hasan Mazumder, Wei Du
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Research Article Aging Hematology

Persistent DNA damage–induced NLRP12 improves hematopoietic stem cell function

Abstract

NOD-like receptor 12 (NLRP12) is a member of the nucleotide-binding domain and leucine-rich repeat containing receptor inflammasome family that plays a central role in innate immunity. We previously showed that DNA damage upregulated NLRP12 in hematopoietic stem cells (HSCs) of mice deficient in the DNA repair gene Fanca. However, the role of NLRP12 in HSC maintenance is not known. Here, we show that persistent DNA damage–induced NLRP12 improves HSC function in both mouse and human models of DNA repair deficiency and aging. Specifically, treatment of Fanca–/– mice with the DNA cross-linker mitomycin C or ionizing radiation induces NLRP12 upregulation in phenotypic HSCs. NLRP12 expression is specifically induced by persistent DNA damage. Functionally, knockdown of NLRP12 exacerbates the repopulation defect of Fanca–/– HSCs. Persistent DNA damage–induced NLRP12 was also observed in the HSCs from aged mice, and depletion of NLRP12 in these aged HSCs compromised their self-renewal and hematopoietic recovery. Consistently, overexpression of NLRP12 substantially improved the long-term repopulating function of Fanca–/– and aged HSCs. Finally, persistent DNA damage–induced NLRP12 maintains the function of HSCs from patients with FA or aged donors. These results reveal a potentially novel role of NLRP12 in HSC maintenance and suggest that NLRP12 targeting has therapeutic potential in DNA repair disorders and aging.

Authors

Qiqi Lin, Limei Wu, Zhilin Ma, Fabliha Ahmed Chowdhury,1, Habibul Hasan Mazumder, Wei Du

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Figure 5

Constitutive overexpression of Nlrp12 improves the long-term repopulating function of Fanca–/– and aged HSCs.

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Constitutive overexpression of Nlrp12 improves the long-term repopulatin...
(A) Schematic presentation of experiment design. (B and C) Ectopic expression of Nlrp12 increases HSC frequencies of Fanca–/– and aged HSCs in secondary transplanted mice. LSK cells from WT and Fanca–/– mice (B), or young and old mice (C), were transduced with lentiviral vector expressing EGFP alone (Vector) or EGFP-NLRP12. Two thousand sorted cells, along with 2 × 105 protector cells, were transplanted into lethally irradiated BoyJ recipients. Sixteen weeks posttransplant, WBMCs were pooled for secondary transplantation into sublethally irradiated BoyJ mice. WBMCs from the secondary recipients were subjected to flow cytometry analysis for the frequencies of donor-derived (GFP+CD45.2+) SLAM cells at 16 weeks posttransplant. Representative flow plots (left) and quantification (right) are shown (n = 9 per group). (D) Overexpression of NLRP12 does not affect apoptosis. WBMCs from the secondary recipients described in C and D were subjected to flow cytometry analysis for apoptosis in donor-derived SLAM cells. Representative flow plots (left) and quantification (right) are shown (n = 9 per group). (E) Overexpression of NLRP12 increases quiescence of Fanca–/– and aged HSCs. WBMCs from the recipients described in C and D were subjected to flow cytometry analysis for cell cycle in donor-derived SLAM cells. Representative flow plots (left) and quantification (right) are shown (n = 9 per group). *P < 0.05; **P < 0.01. Paired or unpaired 2-tailed Student’s t test was used for 2-group comparison and 1-way ANOVA for comparison of more than 2 groups.