Design and development of 5-(4H)-oxazolones as potential inhibitors of human carbonic anhydrase VA: towards therapeutic management of diabetes and obesity.

Inhibitors of carbonic anhydrase (CAIs) hold promise for addressing various diseases, including cancer, diabetes, and other metabolic syndromes. CAV is the only isoform present in the mitochondria and is considered a potential drug target for obesity. In this work, we have developed C2, and C4 substituted oxazole-5(4H)-one derivatives as a new scaffold for the selective inhibition of human carbonic anhydrase VA (hCAVA). Synthesized compounds were characterized by 1H NMR, 13C NMR, and LC-MS mass spectrometry and subsequently evaluated for in vitro hCAVA inhibition. Two compounds, 4 and 5 showed a considerably higher binding affinity for hCAVA in comparison to the hCAII. Further, cell-based studies showed that these compounds decrease the expression of CAVA and GLUT4 in adipocytes and non-toxic to HEK293 cells. The present work opens a platform for the use of oxazole-5(4H)-ones and holds promise for further refinement of potent and selective hCAVA inhibitors.Communicated by Ramaswamy H. Sarma.

HBOA ameliorates CCl4-incuded liver fibrosis through inhibiting TGF-ß1/Smads, NF-κB and ERK signaling pathways.

An ingredient was isolated from Acanthus ilicifolius and identified as 4-hydroxy-2(3H)-benzoxazolone (HBOA). Its protective effects and underlying mechanism on liver fibrosis were investigated. Briefly, rats were intragastrically administrated with 50% CCl4 twice a week for 12 weeks to induce liver fibrosis. Meanwhile, the animals were treated with various medicines from weeks 8 to 12. Then the histological change, serum biochemical index, inflammatory factors and hepatocyte apoptosis were detected. Moreover, the TGF-ß1/Smads, NF-κB and ERK signaling pathways were also detected to illustrate the underlying mechanism. The results showed that HBOA significantly ameliorated CCl4-induced liver injury and collagen accumulation in rats, as evidenced by the histopathologic improvement. Moreover, HBOA markedly decreased hepatocyte apoptosis by regulating the expression levels of caspase-3, -9 and -12, as well as the Bcl-2 family. The mechanism study showed that HBOA significantly decreased the expressions of α-smooth muscle actin (α-SMA) and collagen and inhibited the generation of excessive extracellular matrix (ECM) components by restoring the balance between matrix metalloproteinases (MMPs) and its inhibitor (TIMPs). HBOA markedly alleviated oxidative stress and inflammatory cytokines through inhibiting the NF-κB pathway. In addition, HBOA significantly down-regulated the levels of TGF-ß1, Smad2/3, Smad4 and up-regulated the level of Smad7, inhibiting the TGF-ß1/Smads signaling pathway. Moreover, HBOA significantly blocked the ERK signaling pathway, leading to the inactivation of hepatic stellate cells. This study suggests that HBOA exerts a protective effect against liver fibrosis via modulating the TGF-ß1/Smads, NF-κB and ERK signaling pathways, which will be developed as a potential agent for the treatment of liver fibrosis.

Antibody buffering of a ligand in vivo.

Clearance is the practical limit on drug action. Here we propose a means of slowing clearance, thereby extending drug lifetime in vivo by "antibody buffering." In this process, a drug and an anti-drug antibody are coadministered. Most of the drug is bound to the antibody, preventing the drug from acting, but also preventing its elimination. A dynamic free drug pool is established by reversible dissociation from the antibody. The free drug is active and can be eliminated, but the free pool is constantly replenished by reequilibration from the antibody-drug complex, giving a long effective lifetime. Here we explore antibody buffering experimentally by using a model compound, 2-phenyloxazol-5-one-gamma-aminobutyrate (Ox), as a drug proxy. We show that antibody buffering can extend by an order of magnitude the plasma lifetime of Ox in rats, and that the steady-state Ox level depends on the molecular properties of the antibody used to buffer the Ox. In addition, the anti-Ox antibody can be recharged with drug in vivo to extend Ox lifetime without additional antibody administration, making this technique even more suitable for possible clinical application.

Ciprofloxacin-induced acute psychosis in a patient with multidrug-resistant tuberculosis.

Tuberculosis (TB) increasingly appears in a multidrug-resistant form (MDR-TB) in Europe, too. Treatment remains difficult due to various side effects of the multi-drug-regimens. Ciprofloxacin is widely used as one of the few TB-second-line drugs. We report on the course of a ciprofloxacin-induced acute psychosis in a patient with MDR(isoniazid, streptomycin)-TB which resolved after cessation of ciprofloxacin treatment and introduction of a novel oxazolidone. Careful treatment considerations particularly in patients with additional predisposing factors to neuropsychiatric symptoms are recommended in the potentially dangerous MDR-TB, thus creating an enormous therapeutic challenge.

The effect of carrier and carrier priming on the kinetics and pattern of somatic mutation in the V chi Ox1 gene.

Priming mice with a chicken gamma globulin (CGG) carrier protein significantly accelerated the onset of somatic mutation in the V chi Ox1 gene when the mice were subsequently immunized with 2-phenyl-5-oxazolone (phOx) coupled to CGG. The first mutations were already detected 7 days after immunization, while in the true primary response, they are not apparent until day 10. It was also found that comparing the mutation pattern of V chi Ox1 genes from hybridomas derived after immunization with phOx coupled to different carriers revealed quite distinct patterns of somatic mutation. Analysis of hybridoma sequences from the primary immune response to phOx-ovalbumin showed that the codons for Ser29, Ser31 and Lys45 were hot-spots for somatic mutation. Thus, the frequency and pattern of somatic mutations in the V chi Ox1 gene depends on the available T cell help as well as on the complex structure of the immunizing antigen.