5-hydroxymethylcytosine (5hmC) is enriched in brain and has been recognized as an important DNA modification. However, the roles of 5hmC and its writers, ten-eleven translocation (Tet) proteins, in stress-induced response have yet to be elucidated. Here, we show that chronic restraint stress (CRS) induced depression-like behavior in mice and resulted in a 5hmC reduction in prefrontal cortex (PFC). We found that loss of Tet1 (Tet1 KO) led to resistance to CRS, whereas loss of Tet2 (Tet2 KO) increased the susceptibility of mice to CRS. Genome-wide 5hmC profiling identified the phenotype-associated stress-induced dynamically hydroxymethylated loci (PA-SI-DhMLs), which are strongly enriched with hypoxia-induced factor (HIF) binding motifs. We demonstrated the physical interaction between TET1 and HIF1α induced by CRS and revealed that the increased HIF1α binding under CRS is associated with SI-DhMLs. These results suggest that TET1 could regulate stress-induced response by interacting with HIF1α. The roles of 5-hydroxymethylcytosine (5hmC) and its writers, Tet proteins, in stress-induced response remain unclear. Cheng et al. show that Tet1 knockout mice exhibit resistance, whereas Tet2 knockout mice have increased susceptibility to stress. Biochemical and genome-wide analyses suggest that Tet1 could regulate stress-induced response by interacting with Hif1α.
by
Xuyu Qian;
Ha Nam Nguyen;
Mingxi M. Song;
Christopher Hadiono;
Sarah C. Ogden;
Christy Hammack;
Bing Yao;
Gregory Hamersky;
Fadi Jacob;
Chun Zhong;
Ki-Joon Yoon;
William Jeang;
Li Lin;
Yujing Li;
Jai Thakor;
Daniel Berg;
Ce Zhang;
Eunchai Kang;
Michael Chickering;
David Nauen;
Cheng-Ying Ho;
Zhexing Wen;
Kimberly M Christian;
Pei-Yong Shi;
Brady J. Maher;
Hao Wu;
Peng Jin;
Hao Tang;
Hongjun Song;
Guo-li Ming
Cerebral organoids, three-dimensional cultures that model organogenesis, provide a new platform to investigate human brain development. High cost, variability, and tissue heterogeneity limit their broad applications. Here, we developed a miniaturized spinning bioreactor (SpinΩ) to generate forebrain-specific organoids from human iPSCs. These organoids recapitulate key features of human cortical development, including progenitor zone organization, neurogenesis, gene expression, and, notably, a distinct human-specific outer radial glia cell layer. We also developed protocols for midbrain and hypothalamic organoids. Finally, we employed the forebrain organoid platform to model Zika virus (ZIKV) exposure. Quantitative analyses revealed preferential, productive infection of neural progenitors with either African or Asian ZIKV strains. ZIKV infection leads to increased cell death and reduced proliferation, resulting in decreased neuronal cell-layer volume resembling microcephaly. Together, our brain-region-specific organoids and SpinΩ provide an accessible and versatile platform for modeling human brain development and disease and for compound testing, including potential ZIKV antiviral drugs.
TET1/2/3 are methylcytosine dioxygenases that regulate cytosine hydroxymethylation. Tet1/2 are abundantly expressed in HSC/HPCs and are implicated in hematological malignancies. Tet2 deletion in mice causes myeloid malignancies, while Tet1-null mice develop B cell lymphoma after an extended period of latency. Interestingly, TET1/2 are often concomitantly downregulated in acute B-lymphocytic leukemia. Here, we investigated the overlapping and non-redundant functions of Tet1/2 using Tet1/2 double-knockout (DKO) mice. DKO and Tet2-/- HSC/HPCs show overlapping and unique 5hmC and 5mC profiles. DKO mice exhibit strikingly decreased incidence and delayed onset of myeloid malignancies in comparison to Tet2-/- mice and in contrast develop lethal B cell malignancies. Transcriptome analysis of DKO tumors reveals expression changes in many genes dysregulated in human B cell malignancies, including LMO2, BCL6, and MYC. These results highlight the critical roles of TET1/2 individually and together in the pathogenesis of hematological malignancies.