Protein acetylation in mitochondria plays critical functions in the pathogenesis of fatty liver disease.

BACKGROUND: Fatty liver is a high incidence of perinatal disease in dairy cows caused by negative energy balance, which seriously threatens the postpartum health and milk production. It has been reported that lysine acetylation plays an important role in substance and energy metabolism. Predictably, most metabolic processes in the liver, as a vital metabolic organ, are subjected to acetylation. Comparative acetylome study were used to quantify the hepatic tissues from the severe fatty liver group and normal group. Combined with bioinformatics analysis, this study provides new insights for the role of acetylation modification in fatty liver disease of dairy cows. RESULTS: We identified 1841 differential acetylation sites on 665 proteins. Among of them, 1072 sites on 393 proteins were quantified. Functional enrichment analysis shows that higher acetylated proteins are significantly enriched in energy metabolic pathways, while lower acetylated proteins are significantly enriched in pathways related to immune response, such as drug metabolism and cancer. Among significantly acetylated proteins, many mitochondrial proteins were identified to be interacting with multiple proteins and involving in lipid metabolism. Furthermore, this study identified potential important proteins, such as HADHA, ACAT1, and EHHADH, which may be important regulatory factors through modification of acetylation in the development of fatty liver disease in dairy cows and possible therapeutic targets for NAFLD in human beings. CONCLUSION: This study provided a comprehensive acetylome profile of fatty liver of dairy cows, and revealed important biological pathways associated with protein acetylation occurred in mitochondria, which were involved in the regulation of the pathogenesis of fatty liver disease. Furthermore, potential important proteins, such as HADHA, ACAT1, EHHADH, were predicted to be essential regulators during the pathogenesis of fatty liver disease. The work would contribute to the understanding the pathogenesis of NAFLD, and inspire in the development of new therapeutic strategies for NAFLD.

LC-MS/MS analysis of pazufloxacin in human plasma and otorrhea: application to a pharmacokinetic study of ear drops / 药学学报

Pazufloxacin eardrops are a topical quinolone agent for the treatment of outer ear infection. The present study evaluated the pharmacokinetics and topical distribution of pazufloxacin eardrops by a sensitive LC-MS/MS method for determining pazufloxacin in plasma and otorrhea. Plasma and otorrhea samples were extracted by acetonitrile-induced protein precipitation and were subjected to liquid chromatography-tandem mass spectrometric analysis with an electrospray ionization interface. The samples were separated on an HSS T3 column (50 mm×2.1 mm, 1.8 μm). To avoid the matrix effect, gradient elution was performed with the mobile phase consisting of methanol and 1 mmol·L-1 ammonium acetate aqueous solution (0.1% formic acid). The ion transitions for pazufloxacin and pazufloxacin-d4 were m/z 319.1→281.2 and m/z 323.1→285.2, respectively, under the multiple reaction monitoring (MRM) mode. The method was linear in the range of 0.010 0 - 8.00 ng·mL-1 for pazufloxacin in plasma and 0.500 - 1 000 ng·mg-1 in otorrhea. The intra- and inter-day accuracy and precision for pazufloxacin in plasma and in otorrhea met acceptable criteria. The clinical trial was approved by the Society of Ethics and conducted in Nanjing First Hospital and Jiangsu Province Hospital. The validated methods were used in a systemic and topical pharmacokinetic study of 0.1% pazufloxacin eardrops in 3 patients with chronic suppurative otitis media.