nM For Liver Research Articles

Cinnamaldehyde hydrazone derivatives as potential cathepsin B inhibitors: parallel in-vitro investigation in liver and cerebrospinal fluid

The emergence of cathepsins as a potential target for anticancer drugs has led to extensive research in the development of their inhibitors. In the present study, we designed, synthesized, and characterized several cinnamaldehyde schiff bases employing diverse hydrazines, as potential cathepsin B inhibitors. The parallel studies on cathepsin B isolated from liver and cerebrospinal fluid unveiled the significance of the synthesized compounds as cathepsin B inhibitors at nanomolar concentrations. The compound, 7 exhibited the highest inhibition of 83.48 % and 82.96 % with an IC50 value of 0.06 nM and 0.09 nM for liver and cerebrospinal fluid respectively. The inhibitory potential of synthesized compounds has been extremely effective in comparison to previous reports. With the help of molecular docking studies using iGEMDOCK software, we found that the active site -CH2SH group is involved in the case of α-N-benzoyl-D, l-arginine-b-naphthylamide (BANA), curcumin 2, 3, 6, and 7. For toxicity prediction, ADMET studies were conducted and the synthesized compounds emerged to be non-toxic. The results obtained from the in vitro studies were supported with in silico studies. The synthesized cinnamaldehyde schiff bases can be considered promising drug candidates in conditions with elevated cathepsin B levels.

Tissular localization and excretion of intravenously administered silica nanoparticles of different sizes

The nanotoxicology as a new subdiscipline of nanotechnology needs to be studied in vivo. To do so, it is essential to understand certain pharmacological information of the nanoparticles in vivo. Silica nanoparticles (SiNPs) have been developed for a number of biomedical uses; however, research on their tissular localization and excretion has been limited. In this study, we analyzed the localization of intravenously administered SiNPs with sizes of 20 and 80 nm in liver and spleen and quantitatively investigated the excretion of SiNPs through urine and feces. The results of the tissular localization study showed that the SiNPs were located in liver evenly; however, they were mainly accumulated in the white pulp of spleen. The quantitative excretory assay found the renal excretion being the main excretion pathway of SiNPs and indicated that the accumulated excretory rate of 80 nm SiNPs through urine was higher than that of 20 nm SiNPs because of the higher hemoconcentration. Further analysis of radioactive substances in the excreta showed the convincing confirmatory evidence that the SiNPs of both the sizes of 20 and 80 nm could be excreted through urine. These results provide important information on in vivo distribution and excretion of SiNPs.

Inhibition of rat liver and duodenum soluble catechol- O-methyltransferase by a tight-binding inhibitor OR-462

The inhibition kinetics of rat liver and duodenum soluble catechol- O-methyltransferase (COMT) with a disubstituted catechol OR-462 was studied. After preincubation of the enzyme and inhibitor in the presence of magnesium and S-adenyosylmethionine, an inhibition about thirty times greater than that without preincubation was observed. Reversible tight-binding inhibition was demonstrated with K i values of 0.7 nM and 1.0 nM for liver and duodenum enzyme, respectively. K m values of 53.4 μM and 56.9 μM for substrate 3,4-dihydroxybenzoic acid and 23.0 μM and 17.5 μM for S-adenosylmethionine were calculated for liver and duodenum enzyme, respectively. A catalytic number of 24/min for liver soluble COMT was calculated.

Isolation and characterization of proteolipids from rat liver (LSP) and kidney (KSP).

AbstractIn this study, the biochemical characteristics of proteolipids of rat liver and kidney homogenates were compared. In all preparations, the proteo‐lipids were eluted at the void volume of the Biogel A‐15 m column after gel chromatography, and a molecular weight over 15×106 was estimated. Electron microscopy of the concentrated void volume fractions showed globular particles with diameters of 30–100 nm for liver (LSP) and 30–60 nm for kidney (KSP) preparations that might be formed from plasma membrane fragments. After ultracentrifugation in a CsCl gradient, rat LSP and KSP floated in a small density range from 1.16–1.17 g/ml. There was no significant difference between the relative percentages of phospholipids, triglycerides and cholesterol of both proteo‐lipids. However, the relative mean amount of total protein in rat KSP (60.4% vs 50.4%) was significantly higher and the content of free fatty acids (4.3% vs 12.6%) significantly lower compared to rat LSP. SDS‐PAGE revealed at least 12 protein subunits ranging from 15,000–130,000 in both preparations, but one protein of about Mr 49,000 might represent a liver specific component. The isolated proteo‐lipids from rat liver and kidney homogenates showed similar biochemical characteristics as those from human sources, which could explain the known cross‐reactivity of antibodies against these preparations.The putative function of these proteo‐lipids is not known, although there is some evidence from human studies that they carry receptor proteins.

Insulin receptors of chicken liver and brain. Characterization of alpha and beta subunit properties.

Receptors on membranes of chicken liver and brain bound porcine 125I-insulin in a specific and temperature-dependent manner. Competition with unlabeled insulin derivatives exhibited typical insulin potency ratios, i.e. chicken greater than porcine insulin greater than human proinsulin (2.1/1/0.02). Apparent binding affinity was higher in brain with a 50% inhibition of tracer binding of 1.3 +/- 0.2 nM porcine insulin as compared to 2.8 +/- 0.3 nM in liver. The apparent molecular mass of the 125I-insulin cross-linked alpha subunit of the insulin receptor was 139 +/- 2 kDa for chicken liver and 127 +/- 2 kDa for chicken brain. These molecular masses were similar to those of rat liver and brain insulin receptors. Neuraminidase treatment of the cross-linked insulin receptor increased the mobility of the alpha subunit from liver but did not affect that from brain, suggesting a difference in the glycosylation of the chicken brain alpha subunit as previously described in the rat. Despite this change, both receptors could be purified on wheat germ agglutinin (WGA) chromatography after Triton solubilization. In the presence of CTP and vanadate (phosphatase inhibitors) insulin-stimulatable tyrosine-specific phosphorylation of exogenous substrates was demonstrated with chicken liver and brain receptors. The reaction was dependent on Mg2+ and Mn2+. As noted with other insulin receptors, the best artificial substrate for phosphorylation was poly(Glu,Tyr)4:1. In both chicken liver and brain the smallest effective insulin dose as well as maximal stimulation of phosphorylation of the substrate was similar to that seen with rat liver, and in all three tissues chicken insulin was more potent than porcine insulin. In chicken liver an active ATP hydrolytic activity copurified with the insulin receptors during WGA chromatography. Further purification using S-300 Sephacryl filtration or affinity (insulin-biotin-avidin) chromatography could dissociate the phosphorylation and the hydrolytic activities. Gel electrophoresis, under reducing conditions revealed beta subunits with apparent Mr of 97-99 kDa in chicken liver and brain, which were phosphorylated in the presence of insulin. Similar apparent molecular masses have been described for the beta subunit of rat liver receptors. These studies suggest that both chicken brain and liver insulin receptors exhibit coupling of alpha and beta subunits with fully active tyrosine kinase and that the structural difference of the brain insulin receptor is widespread and phylogenetically old.