Figure 3. Tet2-KO hematopoietic progenitor cells show sustained cell survival and heightened activation of Morrbid in response to acute inflammatory challenge.

(A-B) Level of apoptosis in Lin- cells and LSK cells pre and post LPS treatment as assessed by Annexin-V/7-AAD staining. A, representative flow profile of Annexin/7-AAD staining. B, quantification of apoptosis level.

(C) Differential expression of pro-apoptotic and pro-survival genes in Lin- cells pre- and post-LPS treatment.

(D) A scheme for two possible mechanisms by which Tet2 loss induces hyperactivation of Morrbid: one is through direct regulation of Morrbid promoter and another one is through cytokine-modulated phosphorylation of Stat3 (pStat3), which may bind to Morrbid promoter and activate its expression.

(E-F) Tet2-KO HSPCs maintain elevated expression of pStat3, revealed by flow cytometry (E) and by western blot (F).

(G) Stat3 binds to Morrbid locus revealed by CHIP-qPCR enrichment assay. Shown is relative enrichment in binding (1% of input as unit 1).

Data in (A) is a representative profile of flow cytometry. Data in (B-G) are from a representative experiment (n=4 mice per group, mean ± s.e.m.). Results are representative of two independent experiments. P value: * P < 0.05, ** P < 0.01, *** P < 0.001. n.s., not significant. Statistical analysis performed by unpaired, two-tailed Student’s t-test. See also Figure S3 for additional supporting data.