Objective : To investigate the effect of high concentration of Caerulomycin A (Cae A) on HK2 in renal tubular epithelial cells and to explore the role of cytoplasmic nucleotide⁃binding oligomerization domain⁃like receptor protein 3 (NLRP3) in this process. Methods : The effect of different concentrations of Cae A on the viability of HK2 cells was determined by MTT; the expression of kidney injury molecule (KIM⁃1) and NLRP3 was detected by real⁃time quantitative PCR , Western blot and immunofluorescence , while the effect of Cae A on the mRNA expression of IL⁃1β , IL⁃18 , IL⁃33 , MCP⁃1 , TNF⁃α was also measured by real⁃time quantitative PCR. HK2 cells were divided into control group , high concentration of Cae A group and high concentration of Cae A plus NLRP3 inhibitor CY⁃09 group , and the expression of KIM⁃1 and NLRP3 protein was detected by Western blot. Results : The results of MTT showed that high concentration of Cae A could inhibit HK2 cell viability. Real⁃time quantitative PCR , Western blot and immunofluorescence assays showed that high concentration of Cae A upregulated the expression of KIM⁃1 and NLRP3 , as well as the mRNA levels of IL⁃1β , IL⁃18 , IL⁃33 , MCP⁃1 , TNF⁃α , while CY⁃09 could down⁃regulate the expression of NLRP3 and KIM⁃1. Conclusion High concentration of Cae A significantly inhibited the viability of HK2 cells and induced damage and inflammatory response to HK2 with some nephrotoxicity that might be achieved via NLRP3 pathway.

Ribosomal engineering is a technique that can improve the biosynthesis of secondary metabolites in the antibiotics-resistant mutants by attacking the bacterial RNA polymerase or ribosome units using the corresponding antibiotics. Ribosomal engineering can be used to discover and increase the production of valuable bioactive secondary metabolites from almost all actinomycetes strains regardless of their genetic accessibility. As a consequence, ribosomal engineering has been widely applied to genome mining and production optimization of secondary metabolites in actinomycetes. To date, more than a dozen of new molecules were discovered and production of approximately 30 secondary metabolites were enhanced using actinomycetes mutant strains generated by ribosomal engineering. This review summarized the mechanism, development, and protocol of ribosomal engineering, highlighting the application of ribosomal engineering in actinomycetes, with the aim to facilitate future development of ribosomal engineering and discovery of actinomycetes secondary metabolites.
Actinobacteria/metabolism* ; Actinomyces/genetics* ; Anti-Bacterial Agents/metabolism* ; Multigene Family ; Ribosomes/genetics*