Novel antibacterial drug target against Gram-negative bacteria: lipopolysaccharide transport protein LptDE and its inhibitors / 药学学报

The outer membrane composed predominantly of lipopolysaccharide (LPS) is an essential biological barrier for most Gram-negative (G-) bacteria. Lipopolysaccharide transport protein (Lpt) complex LptDE is responsible for the critical final stage of LPS transport and outer membrane assembly. The structure and function of LptDE are highly conserved in most G- bacteria but absent in mammalian cells, and thus LptDE complex is regarded as an attractive antibacterial target. In recent 10 years, the deciphering of the three-dimensional structure of LptDE protein facilities the drug discovery based on such "non-enzyme" proteins. Murepavadin, a peptidomimetic compound, was reported to be the first compound able to target LptD, enlightening a new class of antibacterial molecules with novel mechanisms of action. This article is devoted to summarize the molecular characteristics, structure-function of LptDE protein complex and review the development of murepavadin and related peptidomimetic compounds, in order to provide references for relevant researches.

Comparison of in vivo pharmacokinetics of five constituents in Zhishi Zhizi Chi Decoction in normal rats and CUMS-induced depressive rats / 中国中药杂志

A LC-MS/MS method was developed for the rapid and simultaneous determination of genipin-1-β-D-gentiobioside,geniposide,naringin,hesperidin and neohesperidin in SD rat plasma.The linear relationships of these five constituents in rats were validated,and the specificity,accuracy,precision and stability met the requirements.Their pharmacokinetic parameters were calculated by DAS 3.2.2,and the results showed that the metabolic process in vivo of the five constituents accorded with the characteristics of noncompartmental model.Their main pharmacokinetic parameters were listed as follows:(1) genipin-1-β-D-gentiobioside:t_(1/2)(3.20±0.51)h,C_(max)(403.15±96.93)μg·L~(-1)and AUC_(0-t)(612.56±148.50)μg·L~(-1)·h for the model group,while t_(1/2)(3.07±0.75) h,C_(max)(229.50±60.63)μg·L~(-1)and AUC_(0-t)(413.14±76.37)μg·L~(-1)·h for the normal group;(2) geniposide:t_(1/2)(3.24±0.68) h,C_(max)(2 961.40±688.02)μg·L~(-1),and AUC_(0-t)(10 972.87±1 992.96)μg·L~(-1)·h for the model group,while t_(1/2)(4.56±0.96) h,C_(max)(1 833.27±558.13)μg·L~(-1),and AUC_(0-t)(8 996.27±3 053.48)μg·L~(-1)·h for the normal group;(3) naringin:t_(1/2)(1.64±0.59) h,C_(max)(415.13±259.54)μg·L~(-1),and AUC_(0-t)(608.62±289.05)μg·L~(-1)·h for the model group,while t_(1/2)(1.02±0.25) h,C_(max)(355.08±180.00)μg·L~(-1),and AUC_(0-t)(501.07±242.68)μg·L~(-1)·h for the normal group;(4) hesperidin:t_(1/2)(0.86±0.29) h,C_(max)(95.17±22.80)μg·L~(-1)and AUC_(0-t)(141.19±54.63)μg·L~(-1)·h for the model group,while t_(1/2)(0.95±0.31) h,C_(max)(46.48±18.33)μg·L~(-1)and AUC_(0-t)(69.51±14.73)μg·L~(-1)·h for the normal group;(5) neohesperidin:t_(1/2)(0.89±0.29) h,C_(max)(828.78±361.56)μg·L~(-1)and AUC_(0-t)(1 292.29±553.73)μg·L~(-1)·h for the model group,while t_(1/2)(0.90±0.31) h,C_(max)(314.68±172.45)μg·L~(-1)and AUC_(0-t)(385.99±138.55)μg·L~(-1)·h for the normal group.

Effects of Jiaotai Pills on CUMS-induced depression model in mice based on changes of SIRT1 expression in hippocampus / 中国中药杂志

The present study investigated the effects and mechanisms of Jiaotai Pills on depressed mice induced by chronic unpredictable mild stress(CUMS). The CUMS-induced depression model mice were established and the depression behaviors of mice were evaluated by sucrose preference test, open field test, tail suspension test, and forced swimming test. Molecular docking was employed to simulate the interaction of six main active ingredients in Jiaotai Pills with SIRT1. Immunohistochemical staining was used to detect the level of SIRT1 in the hippocampus of mice. Western blot was used to detect the protein expression levels of SIRT1, p-NF-κB p65, NF-κB p65, and FoxO1 in the hippocampus of mice. Enzyme-linked immunosorbent assay(ELISA) kits were used to detect the levels of interleukin(IL)-1β, IL-6, tumor necrosis factor-α(TNF-α), and brain-derived neurotrophic factor(BDNF) in the hippocampus and serum of mice. Biochemical kits were used to detect superoxide dismutase(SOD) activity and malondialdehyde(MDA) and glutathione(GSH) levels in the hippocampus and serum of mice. Liquid chromatography-tandem mass spectrometry(LC-MS/MS) was used to detect the levels of dopamine(DA), 5-hydroxytryptamine(5-HT), and norepinephrine(NE) in the hippocampus and serum of mice. The results showed that the sucrose preference rate, movement distance, and the number of crossing centers were reduced in the model group(P<0.01), and the tail suspension time and swimming immobility time were increased(P<0.01). Molecular docking results indicated good binding of six main active ingredients in Jiaotai Pills to SIRT1. In the hippocampus, the expression level of SIRT1 was reduced(P<0.01), and the levels of p-NF-κB p65/NF-κB p65 and FoxO1 were increased(P<0.01). In the hippocampus and serum, the levels of IL-1β, IL-6, TNF-α, and MDA were increased(P<0.01), and the activity of SOD and the levels of GSH, DA, 5-HT, NE, and BDNF were reduced(P<0.01). The treatment with high-dose Jiaotai Pills increased the sucrose preference rate, movement distance, and the number of crossing centers(P<0.05), reduced tail suspension time and swimming immobility time(P<0.01), elevated hippocampal SIRT1 expression level(P<0.01), decreased hippocampal and serum IL-1β, IL-6, TNF-α, and MDA levels(P<0.01), potentiated SOD activity, and up-regulated GSH, DA, 5-HT, NE, and BDNF levels in the hippocampus and serum(P<0.05, P<0.01) in model mice. In conclusion, the results showed that Jiaotai Pills could improve the depression behaviors of model mice with CUMS-induced depression, and the underlying mechanism was related to the up-regulation of SIRT1 in the hippocampus of mice to exert anti-inflammatory and anti-oxidative stress effects.

Research progresses of small molecule inhibitors targeting TGF-β and its receptors / 药学学报

Transforming growth factor-β (TGF-β) belongs to a group of biologically active cytokines that bind to its receptors to activate Smad signaling and non-Smad signaling pathways. The biological functions of TGF-β include promoting cell epithelial-mesenchymal transition, tissue fibrosis, angiogenesis and tumor immune evasion, as well as dual effects of cancer suppression and cancer promotion. Given the fact that the ligand- and receptors-mediated abnormal activation of TGF-β signaling pathways play an important role in the pathogenesis of multiple diseases such as malignant tumors and tissue fibrosis, more than a dozen small-molecule inhibitors have been developed to block the TGF-β signaling pathways, providing a novel method for controlling the development of these diseases. At present, pirfenidone, an inhibitor for TGF-β production, has been approved for treatment of idiopathic pulmonary fibrosis, while the inhibitors of TGFβRI/ALK5 for therapeutics of tumors or myelodysplastic syndromes, including LY2157299, EW-7197 and LY3200882, are in the phase I to III clinical trials, with additional ones inhibiting TGFβRs such as SB-431542, LY2109761, TP-0427736, and IN-1130 being in the preclinical phase. This paper reviews recent advances in research of small-molecule inhibitors targeting TGF-β and its receptors.

Non-targeted metabolomics in septic mice infected with Klebsiella pneumoniae / 药学学报

UHPLC-QTOF-MS was applied to non-targeted metabolomics study of mice infected with K. pneumoniae ATCC® BAA 2146 to discover potential biomarkers and metabolic pathways that are associated with sepsis. Fifty-eight metabolites were identified by principal components analysis (PCA) and partial least-squares discriminant analysis (OPLS-DA), which was combined with variable projection importance (VIP) and nonparametric test. Eighteen of the 58 metabolites were further found to be involved in 8 metabolic pathways, including nicotinate and nicotinamide metabolism, pyrimidine metabolism, vitamin B6 metabolism, taurine and hypotaurine metabolism, arginine and proline metabolism, alanine, aspartate and glutamate metabolism, D-glutamine and D-glutamate metabolism and glycerophospholipid metabolism.

In vitro metabolism and drug-drug interaction potential of IG-105, a novel antimicrotubule agent / 药学学报

IG-105, N-(2,6-dimethoxypyridine-3-yl)-9-methylcarbazole-3-sulfonamide, a novel antimicrotubule agent, showed potent anticancer activity in a variety of human tumor cells in vitro and in vivo. In order to characterize the metabolism and the possible drug-drug interaction of IG-105, we carried out a series of experiments. Drug metabolizing enzymes involved in IG-105 metabolism were investigated by using pooled human liver microsomes (HLMs) and recombinant cytochrome P450 isoforms (rP450s) respectively. The possible metabolites were analyzed by liquid chromatography-orbitrap-mass spectrometry (LC-Orbitrap-MS). The inhibitory effect of IG-105 on main P450 enzymes was also evaluated. The results showed that IG-105 can be metabolized by a series of rP450s, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5, with the major contribution enzymes being CYP1A2, CYP2B6, CYP2C19, and CYP3A. Three metabolites (M1-M3) were identified and demethylation was the major phase I metabolic reaction for IG-105. IG-105 moderately inhibited CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A enzyme activities with IC50 values of 6.42, 23.64, 0.39, 1.4, and 3.14 μmol·L-1, respectively. Since the biotransformation of IG-105 involves multiple enzymatic pathways, the compound is less likely to be a victim of a concomitantly used medicine which inhibits activity of one of the CYPs. However, as IG-105 showed medium to strong inhibition on CYP1A2, CYP2D6, CYP3A, and CYP2C19, caution is particularly needed when IG-105 is co-administrated with other anticancer drugs which are mainly metabolized by the above enzymes.

Research progresses of Mycobacterium tuberculosis cytochrome P450s as a potential drug target / 药学学报

Identification and validation of a new target is one of the most important steps for new antituberculosis (TB) drug discovery. Researches have shown that Mycobacterium tuberculosis (Mtb) encodes 20 CYP450 enzymes which play important roles in the synthesis and metabolism of lipid, cholesterol utilization, and the electron transport of respiratory chain in Mtb. With the critical roles within the organism as well as the protein structures of six Mtb CYP450 enzymes being clarified, some of them have been highlighted as potential anti-tuberculosis targets. In this paper, the phylogenetic analysis, the structural features, and the enzymatic functions of Mtb CYPs, as well as the mechanism of interactions with selective inhibitors such as azole antifungal agents for the CYPs have been reviewed and summarized. The druggability of the CYPs has also been analyzed for their further utility as targets in high throughput screening and rational design of more selective inhibitors.