Cho IJ

References (5)

Title : Ginseng berry aqueous extract prevents scopolamine-induced memory impairment in mice - Hu_2019_Exp.Ther.Med_18_4388
Author(s) : Hu JR , Chun YS , Kim JK , Cho IJ , Ku SK
Ref : Exp Ther Med , 18 :4388 , 2019
Abstract : Ginseng berry exhibits a diverse range of pharmacological activities. The present study aimed to examine the neuroprotective effects of ginseng berry aqueous extract (GBE) against oxidative stress and to assess the impact of GBE on memory impairment in mice. In HT-22 cells, GBE pretreatment significantly inhibited glutamate- and hydrogen peroxide-mediated cytotoxicity in a concentration-dependent manner, while treatment with up to 100 microg/ml GBE alone did not change cell viability. In a murine model of scopolamine (SCP)-induced memory impairment, results from the passive avoidance test and the Morris water maze test indicated that GBE administration for 4 weeks prolonged step-through latency time and shortened escape latency time, suggesting that GBE can attenuate deficits in long-term memory induced by SCP. Additionally, GBE prevented SCP-induced reductions in acetylcholine by decreasing acetylcholinesterase activity and upregulating choline acetyltransferase mRNA levels in the hippocampus. GBE mitigated SCP-mediated mRNA decreases in brain-derived neurotrophic factor levels and its associated signaling molecules. Furthermore, GBE administration significantly suppressed malondialdehyde production and increased glutathione levels, catalase activity and superoxide dismutase activity in SCP-induced memory impaired mice. Therefore, the results of the current study indicated that ginseng berry may be a potential candidate for treating or preventing memory deficits that are associated with neurodegenerative disorders.
ESTHER : Hu_2019_Exp.Ther.Med_18_4388
PubMedSearch : Hu_2019_Exp.Ther.Med_18_4388
PubMedID: 31772634

Title : Reply to 'Conformational fitting of a flexible oligomeric substrate does not explain the enzymatic PET degradation' -
Author(s) : Seo H , Cho IJ , Joo S , Son HF , Sagong HY , Choi SY , Lee SY , Kim KJ
Ref : Nat Commun , 10 :5582 , 2019
PubMedID: 31811201

Title : Rational Protein Engineering of Thermo-Stable PETase from Ideonella sakaiensis for Highly Efficient PET Degradation - Son_2019_ACS.Catal_9_3519
Author(s) : Son HF , Cho IJ , Joo S , Seo H , Sagong HY , Choi SY , Lee SY , Kim KJ
Ref : ACS Catal , 9 :3519 , 2019
Abstract : Widespread utilization of polyethylene terephthalate (PET) has caused a variety of environmental and health problems; thus, the enzymatic degradation of PET can be a promising solution. Although PETase from Ideonalla sakaiensis (IsPETase) has been reported to have the highest PET degradation activity under mild conditions of all PET-degrading enzymes reported to date, its low thermal stability limits its ability for efficient and practical enzymatic degradation of PET. Using the structural information on IsPETase, we developed a rational protein engineering strategy using several IsPETase variants that were screened for high thermal stability to improve PET degradation activity. In particular, the IsPETaseS121E/D186H/R280A variant, which was designed to have a stabilized beta6-beta7 connecting loop and extended subsite IIc, had a Tm value that was increased by 8.81 C and PET degradation activity was enhanced by 14-fold at 40 C in comparison with IsPETaseWT. The designed structural modifications were further verified through structure determination of the variants, and high thermal stability was further confirmed by a heat-inactivation experiment. The proposed strategy and developed variants represent an important advancement for achieving the complete biodegradation of PET under mild conditions
ESTHER : Son_2019_ACS.Catal_9_3519
PubMedSearch : Son_2019_ACS.Catal_9_3519
Gene_locus related to this paper: idesa-mheth

Title : Structural insight into molecular mechanism of poly(ethylene terephthalate) degradation - Joo_2018_Nat.Commun_9_382
Author(s) : Joo S , Cho IJ , Seo H , Son HF , Sagong HY , Shin TJ , Choi SY , Lee SY , Kim KJ
Ref : Nat Commun , 9 :382 , 2018
Abstract : Plastics, including poly(ethylene terephthalate) (PET), possess many desirable characteristics and thus are widely used in daily life. However, non-biodegradability, once thought to be an advantage offered by plastics, is causing major environmental problem. Recently, a PET-degrading bacterium, Ideonella sakaiensis, was identified and suggested for possible use in degradation and/or recycling of PET. However, the molecular mechanism of PET degradation is not known. Here we report the crystal structure of I. sakaiensis PETase (IsPETase) at 1.5 A resolution. IsPETase has a Ser-His-Asp catalytic triad at its active site and contains an optimal substrate binding site to accommodate four monohydroxyethyl terephthalate (MHET) moieties of PET. Based on structural and site-directed mutagenesis experiments, the detailed process of PET degradation into MHET, terephthalic acid, and ethylene glycol is suggested. Moreover, other PETase candidates potentially having high PET-degrading activities are suggested based on phylogenetic tree analysis of 69 PETase-like proteins.
ESTHER : Joo_2018_Nat.Commun_9_382
PubMedSearch : Joo_2018_Nat.Commun_9_382
PubMedID: 29374183
Gene_locus related to this paper: idesa-peth

Title : Tacrine, an Oral Acetylcholinesterase Inhibitor, Induced Hepatic Oxidative Damage, Which Was Blocked by Liquiritigenin through GSK3-beta Inhibition - Park_2015_Biol.Pharm.Bull_38_184
Author(s) : Park SM , Ki SH , Han NR , Cho IJ , Ku SK , Kim SC , Zhao RJ , Kim YW
Ref : Biol Pharm Bull , 38 :184 , 2015
Abstract : Although the cholinesterase inhibitor tacrine has been successfully used for the treatment of Alzheimer's disease, it is known to have hepatotoxic effects. Liquiritigenin (LQ), an active flavonoid in Glycyrrhizae radix, exerts protective effects against liver damage. This study investigated the toxic effect of tacrine on hepatocytes and the beneficial effect of LQ on tacrine intoxication in vivo and in vitro, and the underlying mechanism involved. In hepatocyte cell lines, tacrine induced cell death and oxidative stress, as indicated by decreases in cell viability and glutathione (GSH) contents, which were blocked by pretreatment with LQ. Fluorescent activated cell sorter (FACS) analysis revealed that LQ inhibited cellular H2O2 production and mitochondrial dysfunction induced by tacrine in HepG2 cells. Furthermore, LQ promoted inhibitory phosphorylation of glycogen synthase kinase-3beta (GSK3beta) and prevented decreases in GSK3beta phosphorylation induced by tacrine. In rats treatment with tacrine at 30 mg/kg increased hepatic damage as assessed by blood biochemistry and histopathology. Administration of LQ (10 or 30 mg/kg/d, per os (p.o.)) or the hepatoprotective drug sylimarin (100 mg/kg/d) for 3 d inhibited elevations in alanine aminotransferase, aspartate aminotransferase, and histological changes induced by tacrine. These results show that LQ efficaciously protects the rat liver against tacrine-induced liver damage, and suggest that LQ is a therapeutic candidate for ameliorating the hepatotoxic effects of tacrine.
ESTHER : Park_2015_Biol.Pharm.Bull_38_184
PubMedSearch : Park_2015_Biol.Pharm.Bull_38_184
PubMedID: 25747977