Rubia cordifolia L. ameliorates DSS-induced ulcerative colitis in mice through dual inhibition of NLRP3 inflammasome and IL-6/JAK2/STAT3 pathways.

The aerial part of â€‹Rubia cordifolia â€‹L. has been used as an herbal medicine for a long time with various pharmacological activities, including anti-inflammatory, anticancer, and antibacterial activities. The most notable usage of these was that this herbal medicine had good therapeutic effects on diarrhea caused by various factors. However, the mechanism for the ethanolic extract of â€‹R. cordifolia â€‹L. (RCEE) to treat Ulcerative colitis (UC) effectively is still unclear. In this study, DSS successfully induced UC mice and then intervene using different polar parts of RCEE. The results indicated that RCEE-treatment inhibited colonic combination NLRP3 inflammasome formation and IL-6/JAK2/STAT3 activation in vivo, significantly ameliorating the clinical symptoms, including alleviating colonic mucosal damage and infiltration of macrophages, suppressing the release of inflammatory cytokines, and reducing mortality. Taken together, this study suggests that dual inhibition of NLRP3 inflammasome and IL-6/JAK2/STAT3 pathways activation using RCEE may be a promising therapeutic strategy for preventing the progression of UC.

Bright near-infrared fluorescence bio-labeling with a biliprotein triad.

Biliproteins have extended the spectral range of fluorescent proteins into the near-infrared region (NIR, 700-770 nm) of maximal transmission of most tissues and are also favorable for multiplex labeling. Their application, however, presents considerable challenges to increase their stability under physiological conditions and, in particular, to increase their brightness while maintaining the emission in near-infrared regions: their fluorescence yield generally decreases with increasing wavelengths, and their effective brightness depends strongly on the environmental conditions. We report a fluorescent biliprotein triad, termed BDFP1.1:3.1:1.1, that combines a large red-shift (722 nm) with high brightness in mammalian cells and high stability under changing environmental conditions. It is fused from derivatives of the phycobilisome core subunits, ApcE2 and ApcF2. These two subunits are induced by far-red light (FR, 650-700 nm) in FR acclimated cyanobacteria. Two BDFP1.1 domains engineered from ApcF2 covalently bind biliverdin that is accessible in most cells. The soluble BDFP3 domain, engineered from ApcE2, binds phytochromobilin non-covalently, generating BDFP3.1. This phytochromobilin chromophore was added externally; it is readily generated by an improved synthesis in E. coli and subsequent extraction. Excitation energy absorbed in the FR by covalently bound biliverdins in the two BDFP1.1 domains is transferred via fluorescence resonance energy transfer to the non-covalently bound phytochromobilin in the BDFP3.1 domain fluorescing in the NIR around 720 nm. Labeling of a variety of proteins by fusion to the biliprotein triad is demonstrated in prokaryotic and mammalian cells, including human cell lines.

Far-red acclimating cyanobacterium as versatile source for bright fluorescent biomarkers.

Far-red and near-infrared emitting chromophores extend applications of fluorescent proteins to regions of maximal transmission of most tissues, but present considerable engineering challenges. Far-red adapting cyanobacteria generate a novel set of biliproteins. One of them, ApcF2, from a thermophilic cyanobacterium was subjected to structure-guided, site-directed random and specific mutagenesis, and was screened for bright far-red emission. We report the generation of chromoproteins, termed BDFPs, that are small, bind auto-catalytically the ubiquitous biliverdin as chromophore, express well, and retain their fluorescence in mammalian cells and in the nematode, C. elegans. They are, moreover, photostable and tolerate high temperature, low pH and chemical denaturation. Homo-bichromophoric tandems of these proteins improve labeling, while hetero-bichromophoric systems with large Stokes shifts are suitable for applications like FRET, multi-channel or super-resolution microscopy. The BDFPs compare favorably to other biliproteins and provide a novel, extremely versatile labeling tool-box.

Small monomeric and highly stable near-infrared fluorescent markers derived from the thermophilic phycobiliprotein, ApcF2.

Biliproteins have extended the spectral range of fluorescent proteins into the region of maximal transmission of most tissues and are favorable for multiplexing, but their application presents considerable challenges. Their fluorescence derives from open-chain tetrapyrrole chromophores which often require the introduction of dedicated reductases and lyases. In addition, their fluorescence yield generally decreases with increasing wavelengths and depends strongly on the state of the binding protein. We report fluorescent biliproteins, termed BDFPs, that are derived from the phycobilisome core subunit, ApcF2: this subunit is induced in the thermophilic cyanobacterium, Chroococcidiopsis thermalis, by far-red light and binds phycocyanobilin non-covalently. The BDFPs obtained by molecular evolution of ApcF2 bind the more readily accessible biliverdin covalently while retaining the red-shifted fluorescence in the near-infrared spectral region (~710nm). They are small monomers (~15kDa) and not only show excellent photostability, but are also thermostable up to 80°C, tolerate acid down to pH2 and high concentrations of denaturants. The result indicates far-red adapting cyanobacteria as a useful source for designing extremely red-shifted fluorescent markers. In vivo performance of BDFPs as biomarkers in conventional and super-resolution microscopy, alone or fused to target proteins, is exemplified in several mammalian cells, including, human cell lines, in the nematode, Caenorhabditis elegans and, at low pH, in Lactobacillus lactis.