Search bioRxiv⌕ Search

bioRxiv · 10.1101/830224

Natural naphthoquinones isolated from Lithospermum erythrorhizon suppress dextran sulfate sodium-induced murine experimental colitis

Abstract

The purpose of this study was to explore the effects of natural shikonin and its derivatives on mice experimental colitis induced by dextran sulfate sodium, and to investigate the underlying mechanisms in vivo. Our results suggested that, intragastric administration of single compound like shikonin and its derivatives contributed to attenuating symptoms of malignant induced by DSS. Meanwhile, shikonin or its derivatives could also remarkably reduce the disease activity index and histopathological scores, suppress the levels of pro-inflammatory cytokines (including IL-6, IL-1{beta} and TNF-), while increase that of inflammatory cytokine IL-10 in serum. Additionally, both shikonin and alkanin were found to restrain the levels of COX-2, MPO and iNOS in serum and colonic tissues. Moreover, western blotting results demonstrated that shikonin and its derivatives could inhibit the activation of the NLRP3 inflammasome and the NF-{kappa}B signaling pathway, relieve the DSS-induced disruption of colonic epithelial tight junction (TJ) in colonic tissues. Further, docking simulation had been performed to prove that shikonin and its derivatives could bind to the active sites of NLRP3 inflammasome and the NF-{kappa}B to generate an effective inflammatory effect. Taken together, our experimental data can provide some evidence for the potential use of shikonin and its derivatives to treat the inflammatory bowel disease (IBD).

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sun, W. X., Han, H. W., Wang, Z. Y., Wen, Z. L., Yang, M. K., Wang, Y. S., Fu, J. Y., Feng, L., Xu, X. H., Yin, T. M., Wang, X. M., Lu, G. H., Qi, J. L., Lin, H. Y., Yang, Y.- H.. 2019-11-04. Natural naphthoquinones isolated from Lithospermum erythrorhizon suppress dextran sulfate sodium-induced murine experimental colitis. https://doi.org/10.1101/830224

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

The structures of two intermediates en route to DNA repair within a (6-4) photolyase

Pyrimidine (6-4) pyrimidone photoproducts (6-4PPs) are mutagenic DNA lesions produced when UV light crosslinks two adjacent pyrimidine bases. These lesions must be repaired to maintain genome integrity, a function executed by the (6-4) photolyase enzymes. This repair chemistry is complex, involving the transfer of a hydroxyl group from one base to another, accompanied or followed by cleavage of an interbase bond. It remains unclear how the enzyme orchestrates this reaction. Typically, models invoke a stepwise process in which an oxetane intermediate is transiently populated, but despite over thirty years of investigation, such an intermediate has never been definitively observed. Conducting dose-controlled X-ray crystallography on the (6-4) photolyase from Vibrio cholerae, we observed the transformation of 6-4PP into an oxetane species. Furthermore, we identified a previously unanticipated hemi-cleaved intermediate. The progressive transformation of 6-4PP into oxetane, hemi-cleaved, and fully repaired species requires a reexamination of the existing models of DNA repair by (6-4) photolyases.

biochemistry↗

Endothelial protein C receptor is an entry receptor for Langya virus

Langya virus (LayV) was recently discovered in infected individuals with febrile illness and classified as a Parahenipavirus, a group of poorly understood pathogens. LayV is distantly related to Nipah henipavirus which causes recurring outbreaks with case fatality rates reaching up to 90%. No vaccines or therapeutics are approved for use in humans for any parahenipavirus or henipavirus despite their broad geographic distribution and pandemic potential. Here, we discovered that human endothelial protein C receptor (EPCR) is an entry receptor for LayV and that the tetrameric LayV attachment glycoprotein (G) binds EPCR avidly. We reveal the molecular basis of LayV G recognition of the EPCR receptor and provide a blueprint of the determinants of receptor ortholog usage. We found that human and shrew EPCR orthologs promote cell entry of LayV and of the closely related Mojiang pseudoviruses. These results along with the detection of several Parahenipaviruses in shrews set these pathogens apart from Henipaviruses, which use Pteropid fruit bats as reservoir hosts. Our data support future surveillance efforts, by enabling prediction of EPCR utilization among newly discovered Parahenipaviruses, and the development and evaluation of countermeasures targeting this emerging group of human pathogens.

biochemistry↗

RNA-targeted aminopyridine compounds provide a new antifungal strategy

While RNA is an emerging therapeutic target class, progress is limited by a shortage of well-defined targets in which ligand binding is coupled to measurable function. The group I intron, a self-splicing ribozyme essential in fungal mitochondria but absent from humans, offers both a tractable platform for exploring first principles of small molecule-RNA targeting and a selective antifungal target. We recalibrated an intron-splicing assay to approximate cellular conditions and performed an extensive, cryo-EM-guided structure-activity relationship campaign against the Candida albicans mtLSU intron. Ligands containing a flexible diamine outperformed conformationally constrained analogues, suggesting a general principle for engaging dynamic RNA surfaces and yielding lead aminopyridine 56 (IC 21.6 nM). Compound 56 synergizes with amphotericin B against C. albicans, suggesting a path for combination therapies. RT-qPCR confirmed direct target engagement in cells. This work establishes the fungal group I intron as a viable, mechanistically distinct antifungal target and a model platform for RNA-targeted discovery.

biochemistry↗