WenYe Liu,Xi Liu,LingYa Li,ZhiPeng Tai,GuoLiang Li,Jing-Xia Liu
Summary Enhancers of polycomb 1 (EPC1) and 2 (EPC2) are involved in multiple biological processes as components of histone acetyltransferases/deacetylase complexes and transcriptional cofactors, and their dysfunction was associated with developmental defects and diseases. However, it remains unknown how their dysfunction induces hematopoietic stem and progenitor cell (HSPC) defects. Here, we show that depletion of EPC1 / 2 significantly reduced the number of hematopoietic stem and progenitor cells (HSPCs) in the aorta-gonad mesonephros and caudal hematopoietic tissue regions by impairing HSPC proliferation, and consistently downregulated the expression of HSPC genes in K562 cells. This study demonstrates the functions of EPC1 / 2 in regulating histone H3 acetylation, and in regulating DLST (dihydrolipoamide S-succinyltransferase) via H3 acetylation and cooperating with transcription factors serum response factor and FOXR2 together, and in the subsequent HSPC emergence and proliferation. Our results demonstrate the essential roles of EPC1 / 2 in regulating H3 acetylation, and DLST as a linkage between EPC1 and EPC2 with mitochondria metabolism, in HSPC emergence and proliferation.
Cutaneous T-cell lymphomas (CTCLs) represent a rare form of non-Hodgkin lymphomas characterized by an accumulation of malignant CD4 + T cells in the skin. TP53 genetic alteration is one of the most prevalent genetic abnormalities in CTCLs. Therefore, it is a promising target for innovative therapeutic approaches. We found that p53 could physically interact with histone deacetylase (HDAC) 1 and HDAC8, and was subsequently deacetylated to lose its function in CTCL cells, and the p53 downstream apoptosis-associated genes were repressed. Thus, the anti-CTCL activity displayed by HDAC inhibitors depends on p53 status. However, recent studies have reported that HDAC inhibitors could induce a wide variety of drug-resistant characteristics in cancer cells by regulating ATP-binding cassette transporters. Moreover, we discovered that Baicalein, a natural product, exhibited an inhibitory effect on HDAC1 and HDAC8. Though the inhibition of HDAC1 was mild, Baicalein could induce the degradation of HDAC1 through the ubiquitin proteasome pathway, thereby markedly upregulating the acetylation of histone H3 without promoting ATP-binding cassette transporter gene expression. In terms of the mechanism, Baicalein showed better growth inhibition than traditional HDAC inhibitors in CTCLs. This study indicates a special mechanism of HDAC1 and HDAC8 and p53 in T-cell lymphoma cells and identifies a potential and safe natural HDAC inhibitor for the treatment of CTCLs.
In vivo an ecological network of polysaccharides utilization by gut microbiota is not only an intense competition but also an impressive cooperation pattern. The present study evaluated the in vivo protective effect of combined fungal polysaccharides (CFP) from Cordyceps sinensis and Ganoderma atrum on colon immune dysfunction, induced by 150 mg/kg cyclophosphamide (CP). The results showed that C. sinensis polysaccharides (CSP) significantly promoted microbial-derived butyrate to improve histone h3 acetylation mediating regulatory T (Treg) cell specific Foxp3, as well as significantly restored CP-induced elevation of interleukin (IL)-17 and IL-21. Additionally, G. atrum polysaccharides (PSG) significantly down-regulated MyD88, as well as significantly increased IL-10 and TGF-β3. Furthermore, CFP balanced the disequilibrium of cytokines secretion and Foxp3/RORγt ratio related Treg/T helper 17 (Th17) balance, as well as down-regulated the TLR-mediated inflammatory signaling pathway and promoted secretory immunoglobulin A (sIgA) secretion to suppress colonic inflammation. Therefore, our results typically contribute to understand the in vivo immunoregulatory function of fungal polysaccharides compounds, involving microbial-associated inflammatory signals and specific metabolic products.
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