Programmable Biosynthesis of Plant-Derived 4'-Deoxyflavone Glycosides by an Unconventional Yeast Consortium.

Previous data established 4'-deoxyflavone glycosides (4'-DFGs) as important pharmaceutical components in the roots of rare medical plants like Scutellaria baicalensis Georgi. Extracting these compounds from plants involves land occupation and is environmentally unfriendly. Therefore, a modular ("plug-and-play") yeast-consortium platform is developed to synthesize diverse 4'-DFGs de novo. By codon-optimizing glycosyltransferase genes from different organisms for Pichia pastoris, six site-specific glycosylation chassis are generated to be capable of biosynthesizing 18 different 4'-DFGs. Cellular factories showed increased 4'-DFG production (up to 18.6-fold) due to strengthened synthesis of UDP-sugar precursors and blocked hydrolysis of endogenous glycosides. Co-culturing upstream flavone-synthesis-module cells with downstream glycoside-transformation-module cells alleviated the toxicity of 4'-deoxyflavones and enabled high-level de novo synthesis of 4'-DFGs. Baicalin is produced at the highest level (1290.0 mg L-1 ) in a bioreactor by controlling the consortium through carbon-source shifting. These results provide a valuable reference for biosynthesizing plant-derived 4'-DFGs and other glycosides with potential therapeutic applications.

(-)-Epigallocatechin Gallate Targets Notch to Attenuate the Inflammatory Response in the Immediate Early Stage in Human Macrophages.

Inflammation plays important roles at different stages of diabetes mellitus, tumorigenesis, and cardiovascular diseases. (-)-Epigallocatechin gallate (EGCG) can attenuate inflammatory responses effectively. However, the immediate early mechanism of EGCG in inflammation remains unclear. Here, we showed that EGCG attenuated the inflammatory response in the immediate early stage of EGCG treatment by shutting off Notch signaling and that the effect did not involve the 67-kDa laminin receptor, the common receptor for EGCG. EGCG eliminated mature Notch from the cell membrane and the nuclear Notch intercellular domain, the active form of Notch, within 2 min by rapid degradation via the proteasome pathway. Transcription of the Notch target gene was downregulated simultaneously. Knockdown of Notch 1/2 expression by RNA interference impaired the downregulation of the inflammatory response elicited by EGCG. Further study showed that EGCG inhibited lipopolysaccharide-induced inflammation and turned off Notch signaling in human primary macrophages. Taken together, our results show that EGCG targets Notch to regulate the inflammatory response in the immediate early stage.

Pu-erh Tea Water Extract Mediates Cell Cycle Arrest and Apoptosis in MDA-MB-231 Human Breast Cancer Cells.

Pu-erh tea is believed to have health benefits, the growth inhibition activity of Pu-erh tea on breast cancer cell has not been investigated. In this study, we examined the activity of Pu-erh tea water extract on apoptosis and cell cycle arrest in the human breast adenocarcinoma cell line MDA-MB-231 and clarified its underlying mechanism of action. We found that Pu-erh tea extract inhibited cell proliferation and induced apoptosis in a dose-dependent manner. We also found that Pu-erh tea extract inhibited tumor cell growth within 24 h via accumulation of cells in S phase. Further experiments showed that at 24 h, Pu-erh tea extract up-regulated the expressions of P-p53 (Ser15), p21 and P-JNK and down-regulated the expressions of PCNA, CyclinD1 and CyclinE at the protein level in MDA-MB-231 cells. In particular, the JNK-specific inhibitor SP600125 restored the induction of P-JNK, P-p53 (Ser15), p21, CyclinD1 and CyclinE by Pu-erh tea extract. Our results indicate that Pu-erh tea water extract inhibits cell proliferation of MDA-MB-231 cells through the induction of apoptosis and the stimulation of cell cycle arrest, which is mediated via activation of the JNK-related pathway.