Generation and Validation of a Zebrafish Model of EAST (Epilepsy, Ataxia, Sensorineural Deafness and Tubulopathy) Syndrome.

Generation and validation of a zebrafish model of EAST (Epilepsy, ataxia, sensorineural deafness and tubulopathy) syndrome.

Dis Model Mech. 2013 Feb 14;
Mahmood F, Mozere M, Zdebik AA, Stanescu HC, Tobin J, Beales PL, Kleta R, Bockenhauer D, Russell C

Recessive mutations in KCNJ10, which encodes an inwardly rectifying potassium channel, were recently identified as the cause of EAST syndrome, a severe and disabling multi-organ disorder consisting of epilepsy, ataxia, sensorineural deafness and tubulopathy that becomes clinically apparent with seizures in infancy. A Kcnj10 knockout mouse shows postnatal mortality and is therefore not suitable for drug discovery. Because zebrafish are ideal for in vivo screening for potential therapeutics, we tested whether kcnj10 knockdown in zebrafish would fill this need. We cloned zebrafish kcnj10 and demonstrated that its function is equivalent to that of human KCNJ10. We next injected splice- and translation-blocking kcnj10 antisense morpholino oligonucleotides and reproduced the cardinal symptoms of EAST syndrome – ataxia, epilepsy and renal tubular defects. Several of these phenotypes could be assayed in an automated manner. We could rescue the morphant phenotype with complementary RNA (cRNA) encoding human wild-type KCNJ10, but not with cRNA encoding a KCNJ10 mutation identified in individuals with EAST syndrome. Our results suggest that zebrafish will be a valuable tool to screen for compounds that are potentially therapeutic for EAST syndrome or its individual symptoms. Knockdown of kcnj10 represents the first zebrafish model of a salt-losing tubulopathy, which has relevance for blood pressure control. HubMed – drug


Physicochemical Properties of Protein-Coated Gold Nanoparticles in Biological Fluids and Cells before and after Proteolytic Digestion.

Angew Chem Int Ed Engl. 2013 Mar 7;
Chanana M, Rivera Gil P, Correa-Duarte MA, Liz-Marzán LM, Parak WJ

What’s going on in there?! Little is known about the fate of nanoparticles (NPs) after their internalization by cells and organisms. Protein-coated gold NPs were used to study the physicochemical properties of NPs in extra- and intracellular fluids. These potential vehicles for enzymatic drug delivery were highly stable at pH 7.4 in the presence of salts and free proteins, but agglomerated reversibly under acidic conditions. HubMed – drug


Millepachine (MIL), a novel chalcone, induces G2/M arrest by inhibiting CDK1 activity and causing apoptosis via ROS-mitochondrial apoptotic pathway in human hepatocarcinoma cells in vitro and in vivo.

Carcinogenesis. 2013 Mar 7;
Wu W, Ye H, Wan L, Han X, Wang G, Hu J, Tang M, Duan X, Fan Y, He S, Huang L, Pei H, Wang X, Li X, Xie C, Zhang R, Yuan Z, Mao Y, Wei Y, Chen L

In this paper, we reported millepachine (MIL), a novel chalcone compound for the first time isolated from Millettia pachycarpa Benth (Leguminosae) induced cell cycle arrest and apoptosis in human hepatocarcinoma cells in vitro and in vivo. In in vitro screening experiments, MIL showed strong anti-proliferation activity in several human cancer cell lines, especially in HepG2 cells with an IC 50 of 1.51 ?M. Therefore, we chose HepG2 and SK-HEP-1 cells to study MIL’s anti-tumor mechanism. Flow cytometry showed that MIL induced a G2/M arrest and apoptosis in a dose-dependent manner. Western blot demonstrated that MIL-induced G2/M arrest was correlated with the inhibition of CDK1 activity, including a remarkable decrease in cdc2 synthesis, the accumulation of phosphorylated-Thr14 and decrease of phosphorylation at Thr161 of cdc2. This effect was associated with the down-regulation of cdc25C and up-modulation of Chk2 in response to DNA damage. MIL also activated caspase 9 and caspase 3, and significantly increased the ratio of Bax/Bcl-2 and stimulated the release of cytochrome c into cytosol, suggesting MIL induced apoptosis via mitochondrial apoptotic pathway. Associated with those effects, MIL also induced the generation of reactive oxygen species. In HepG2 tumor-bearing mice models, MIL remarkably and dose dependently inhibited tumor growth. Treatment of mice with MIL (20 mg/kg i.v.) caused more than 65% tumor inhibition without cardiac damage compared to 47.57% tumor reduction by 5 mg/kg i.v. doxorubicin with significant cardiac damage. These effects suggested MIL and its easily modified structural derivative might be a potential lead compound for anti-tumor drug. HubMed – drug