Browsing by Author "Liu, Xiaojing"

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    CoA synthase regulates mitotic fidelity via CBP-mediated acetylation.
    (Nature communications, 2018-03-12) Lin, Chao-Chieh; Kitagawa, Mayumi; Tang, Xiaohu; Hou, Ming-Hsin; Wu, Jianli; Qu, Dan Chen; Srinivas, Vinayaka; Liu, Xiaojing; Thompson, J Will; Mathey-Prevot, Bernard; Yao, Tso-Pang; Lee, Sang Hyun; Chi, Jen-Tsan
    The temporal activation of kinases and timely ubiquitin-mediated degradation is central to faithful mitosis. Here we present evidence that acetylation controlled by Coenzyme A synthase (COASY) and acetyltransferase CBP constitutes a novel mechanism that ensures faithful mitosis. We found that COASY knockdown triggers prolonged mitosis and multinucleation. Acetylome analysis reveals that COASY inactivation leads to hyper-acetylation of proteins associated with mitosis, including CBP and an Aurora A kinase activator, TPX2. During early mitosis, a transient CBP-mediated TPX2 acetylation is associated with TPX2 accumulation and Aurora A activation. The recruitment of COASY inhibits CBP-mediated TPX2 acetylation, promoting TPX2 degradation for mitotic exit. Consistently, we detected a stage-specific COASY-CBP-TPX2 association during mitosis. Remarkably, pharmacological and genetic inactivation of CBP effectively rescued the mitotic defects caused by COASY knockdown. Together, our findings uncover a novel mitotic regulation wherein COASY and CBP coordinate an acetylation network to enforce productive mitosis.
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    Metabolic programming and PDHK1 control CD4+ T cell subsets and inflammation.
    (J Clin Invest, 2015-01) Gerriets, Valerie A; Kishton, Rigel J; Nichols, Amanda G; Macintyre, Andrew N; Inoue, Makoto; Ilkayeva, Olga; Winter, Peter S; Liu, Xiaojing; Priyadharshini, Bhavana; Slawinska, Marta E; Haeberli, Lea; Huck, Catherine; Turka, Laurence A; Wood, Kris C; Hale, Laura P; Smith, Paul A; Schneider, Martin A; MacIver, Nancie J; Locasale, Jason W; Newgard, Christopher B; Shinohara, Mari L; Rathmell, Jeffrey C
    Activation of CD4+ T cells results in rapid proliferation and differentiation into effector and regulatory subsets. CD4+ effector T cell (Teff) (Th1 and Th17) and Treg subsets are metabolically distinct, yet the specific metabolic differences that modify T cell populations are uncertain. Here, we evaluated CD4+ T cell populations in murine models and determined that inflammatory Teffs maintain high expression of glycolytic genes and rely on high glycolytic rates, while Tregs are oxidative and require mitochondrial electron transport to proliferate, differentiate, and survive. Metabolic profiling revealed that pyruvate dehydrogenase (PDH) is a key bifurcation point between T cell glycolytic and oxidative metabolism. PDH function is inhibited by PDH kinases (PDHKs). PDHK1 was expressed in Th17 cells, but not Th1 cells, and at low levels in Tregs, and inhibition or knockdown of PDHK1 selectively suppressed Th17 cells and increased Tregs. This alteration in the CD4+ T cell populations was mediated in part through ROS, as N-acetyl cysteine (NAC) treatment restored Th17 cell generation. Moreover, inhibition of PDHK1 modulated immunity and protected animals against experimental autoimmune encephalomyelitis, decreasing Th17 cells and increasing Tregs. Together, these data show that CD4+ subsets utilize and require distinct metabolic programs that can be targeted to control specific T cell populations in autoimmune and inflammatory diseases.
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    Paracrine Wnt5a-β-Catenin Signaling Triggers a Metabolic Program that Drives Dendritic Cell Tolerization.
    (Immunity, 2018-01) Zhao, Fei; Xiao, Christine; Evans, Kathy S; Theivanthiran, Tbalamayooran; DeVito, Nicholas; Holtzhausen, Alisha; Liu, Juan; Liu, Xiaojing; Boczkowski, David; Nair, Smita; Locasale, Jason W; Hanks, Brent A
    Despite recent advances, many cancers remain refractory to available immunotherapeutic strategies. Emerging evidence indicates that the tolerization of local dendritic cells (DCs) within the tumor microenvironment promotes immune evasion. Here, we have described a mechanism by which melanomas establish a site of immune privilege via a paracrine Wnt5a-β-catenin-peroxisome proliferator-activated receptor-γ (PPAR-γ) signaling pathway that drives fatty acid oxidation (FAO) in DCs by upregulating the expression of the carnitine palmitoyltransferase-1A (CPT1A) fatty acid transporter. This FAO shift increased the protoporphyrin IX prosthetic group of indoleamine 2,3-dioxgenase-1 (IDO) while suppressing interleukin(IL)-6 and IL-12 cytokine expression, culminating in enhanced IDO activity and the generation of regulatory T cells. We demonstrated that blockade of this pathway augmented anti-melanoma immunity, enhanced the activity of anti-PD-1 antibody immunotherapy, and suppressed disease progression in a transgenic melanoma model. This work implicates a role for tumor-mediated metabolic reprogramming of local DCs in immune evasion and immunotherapy resistance.