Visual detection of histone acetylation in cells is highly desirable for medical diagnostics, particularly in cancer. Currently, a single substrate-indicated multi-mode visual platform has been developed for detecting the activity of acetyltransferase (KAT Tip60) in circulating tumor cells (CTCs) of esophageal cancer. o-Phenylenediamine (OPD) serves as a single indicator in our constructed multi-mode analytical method, where the introduction of Cu(II) stimulates a change in fluorescent/UV–vis signals and colors. However, coenzyme A (CoA), a byproduct of the acetylation process, effectively prevents the interaction between Cu(II) and OPD, and this competitive reaction is aptly associated with the KAT Tip60-domonicated acetylation process. Good linear relationships are observed between the optical signals in the multi-mode method and the logarithms of the Tip60 concentration, with detection limits of 0.0045 ng/mL (fluorescence) and 0.058 ng/mL (UV–vis), respectively, calculated as 3σ/slope. To meet the needs of smart/precision medicine, a smartphone-based visualization approach tailored to the red-green-blue (RGB) color space is developed via Cu(II)-OPD redox catalysis. This approach is successfully employed for the analysis of Tip60-indicated acetylation in CTCs of esophageal cancer. This study establishes an important foundation for advancing RGB color-based smartphone modes for actual analyses, and integrating another catalytic unit based on the single OPD substrate presents a viable strategy for analyzing other biomarkers in cancer-targeted clinical applications.
Su Xiaoran,Wang Xinliu,Zhang Xin,Sun Yajie,Jia Yugai
Massive evidence shows that intestinal tryptophan metabolites affected by intestinal flora can modulate the progression of rheumatoid arthritis (RA). However, the effects and mechanisms of intestinal tryptophan metabolites on RA are not yet detailed. Herein, we investigated the protective effects of intestinal tryptophan metabolites on RA and its detailed mechanisms. In this study, the collagen-induced arthritis (CIA) rat model was established. Based on metabolomics analysis, the contents of β-indole-3-acetic acid (IAA), indolylpropionic acid, and indole-3-β-acrylic acid in the sera of CIA rats were significantly less compared with those of the normal rats. Under the condition of Treg or Th17 cell differentiation, IAA significantly promoted the differentiation and activation of Treg cells instead of Th17 cells. Intestinal tryptophan metabolites are well-known endogenic ligands of aryl hydrocarbon receptor (AhR). Not surprisingly, IAA increased the level of Foxp3 through activating the AhR pathway. Interestingly, IAA had little impact on the level of Foxp3 mRNA, but reducing the ubiquitination and degradation of Foxp3. Mechanically, IAA reduced the expression of the transcriptional coactivator TAZ, which was almost completely reversed by either AhR antagonist CH223191 or siRNA. In vitro, IAA decreased the combination of TAZ and the histone acetyltransferase Tip60, while it increased the combination of Tip60 and Foxp3. In CIA rats, oral administration of IAA increased the number of Treg cells and relieved the inflammation. A combined use with CH223191 almost abolished the effect of IAA. Taken together, IAA attenuated CIA by promoting the differentiation of Treg cells through reducing the ubiquitination of Foxp3 via the AhR-TAZ-Tip60 pathway.
Histone lysine isonicotinylation (Kinic) induced by isoniazid (INH) was recently identified as a post-translational modification in cells. However, global cellular non-histone proteins Kinic remains unclear. Using proteomic technology, we identified 11,442 Kinic sites across 2,792 proteins and demonstrated that Kinic of non-histone proteins is involved in multiple function pathways. Non-histone proteins Kinic can be regulated by isonicotinyl-transferases, including CBP and Tip60, and deisonicotinylases, including HDAC8 and HDAC6. In particular, the Kinic of poly (ADP-ribose) (PAR) polymerase 1 (PARP1) can be catalyzed by CBP and deisonicotinylation can be catalyzed by HDAC8. Tip60 and HDAC6 are isonicotinyl-transferase and the deisonicotinylase of SMAD3, respectively. Importantly, we found the K378inic of SMAD3 increases its phosphorylation, activates TGFβ pathway, and promotes liver cancer cells migration and invasion. In conclusion, our study demonstrated non-histone proteins Kinic occur extensively in cells and plays an important role in regulation of various cellular functions, including cancer progression.
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