Kidney toxicity accounts for a significant percentage of morbidity and drug candidate failure. Serum creatinine (SCr) and blood urea nitrogen (BUN) have been used to monitor kidney dysfunction for over a century but these markers are insensitive and non-specific. In multi-site preclinical rat toxicology studies the diagnostic performance of urinary kidney injury molecule-1 (Kim-1) was compared to traditional biomarkers as predictors of kidney tubular histopathologic changes, currently considered the “gold standard” of nephrotoxicity. In multiple models of kidney injury, urinary Kim-1 significantly outperformed SCr and BUN. The area under the receiver operating characteristic curve for Kim-1 was between 0.91 and 0.99 as compared to 0.79 to 0.9 for BUN and 0.73 to 0.85 for SCr. Thus urinary Kim-1 is the first injury biomarker of kidney toxicity qualified by the FDA and EMEA and is expected to significantly improve kidney safety monitoring.

The multidrug-resistant mutant Streptococcus pneumoniae M22 constitutively overexpresses two genes (patA and patB) that encode proteins homologous to known efflux proteins belonging to the ABC transporter family. It is shown here that PatA and PatB were strongly induced by quinolone antibiotics and distamycin in fluoroquinolone-sensitive strains. PatA was very important for growth of S. pneumoniae, and it could not be disrupted in strain M22. PatB appeared to control metabolic activity, particularly in amino acid biosynthesis, and it may have a pivotal role in coordination of the response to quinolone antibiotics. The induction of PatA and PatB by antibiotics showed a pattern similar to that exhibited by SP1861, a homologue of ABC-type transporters of choline and other osmoprotectants. A second group of quinolone-induced transporter genes comprising SP1587 and SP0287, which are homologues of, respectively, oxalate/formate antiporters and xanthine or uracil permeases belonging to the major facilitator family, showed a different pattern of induction by other antibiotics. There was no evidence for the involvement of PmrA, the putative proton-dependent multidrug transporter that has been implicated in norfloxacin resistance, in the response to quinolone antibiotics in either the resistant mutant or the fluoroquinolone-sensitive strains.Large epidemiological studies of Streptococcus pneumoniae in clinical infections have associated mutations in the genes encoding gyrase and topoisomerase IV with fluoroquinolone resistance (13, 40). However, resistance to fluoroquinolones can also be mediated by active efflux (5, 9-11, 17, 18, 22, 34, 44, 53). Until recently, the only efflux pump implicated in pneumococcal fluoroquinolone resistance was PmrA (22), but it now appears that there must be other efflux pumps involved in this resistance phenotype (11,45). Multidrug-resistant strain M22, a mutant selected after exposure of S. pneumoniae NCTC 7465 (strain M4) to ciprofloxacin, appeared to have such an efflux-mediated resistance mechanism (46). The mutation frequency of 6.9 ϫ 10 Ϫ8 and stable resistance without antibiotic pressure suggested a mutation in a single gene (46). However, no mutations in the fluoroquinolone resistance-determining regions of the A subunits of DNA gyrase or topoisomerase IV have been detected (36). Strain M22 was at least fourfold more resistant than strain M4 to ciprofloxacin, norfloxacin, acriflavine, ethidium bromide, doxorubicin, tetracycline, erythromycin, and cetrimide. The MICs of clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin, and sitafloxacin were reproducibly twofold higher for strain M22 than for strain M4, but those of moxifloxacin, ofloxacin, sparfloxacin, and chloramphenicol were identical for the two strains. The accumulation of ciprofloxacin, gatifloxacin, and ofloxacin by strain M22 was significantly less than that observed in strain M4, whereas the accumulation of norfloxacin and ethidium was consistently higher than in strain M4. Addition of reserpine increased the uptake...

No abstract

MicroRNAs are short non-coding RNAs that regulate gene expression at the post-transcriptional level and play key roles in heart development and cardiovascular diseases. Here, we have characterized the expression and distribution of microRNAs across eight cardiac structures (left and right ventricles, apex, papillary muscle, septum, left and right atrium and valves) in rat, Beagle dog and cynomolgus monkey using microRNA sequencing. Conserved microRNA signatures enriched in specific heart structures across these species were identified for cardiac valve (miR-let-7c, miR-125b, miR-127, miR-199a-3p, miR-204, miR-320, miR-99b, miR-328 and miR-744) and myocardium (miR-1, miR-133b, miR-133a, miR-208b, miR-30e, miR-499-5p, miR-30e*). The relative abundance of myocardium-enriched (miR-1) and valve-enriched (miR-125b-5p and miR-204) microRNAs was confirmed using in situ hybridization. MicroRNA-mRNA interactions potentially relevant for cardiac functions were explored using anti-correlation expression analysis and microRNA target prediction algorithms. Interactions between miR-1/Timp3, miR-125b/Rbm24, miR-204/Tgfbr2 and miR-208b/Csnk2a2 were identified and experimentally investigated in human pulmonary smooth muscle cells and luciferase reporter assays. In conclusion, we have generated a high-resolution heart structure-specific mRNA/microRNA expression atlas for three mammalian species that provides a novel resource for investigating novel microRNA regulatory circuits involved in cardiac molecular physiopathology.