Soo Young Kim

Chronic exposure to ethanol of male mice before mating produces attention deficit hyperactivity disorder‐like phenotype along with epigenetic dysregulation of dopamine transporter expression in mouse offspring

Preconception exposure to EtOH through the paternal route may affect neurobehavioral and developmental features of offspring. This study investigates the effects of paternal exposure to EtOH before conception on the hyperactivity, inattention, and impulsivity behavior of male offspring in mice. Sire mice were treated with EtOH in a concentration range approximating human binge drinking (0–4 g/kg/day EtOH) for 7 weeks and mated with untreated females mice to produce offspring. EtOH exposure to sire mice induced attention deficit hyperactivity disorder (ADHD)‐like hyperactive, inattentive, and impulsive behaviors in offspring. As a mechanistic link, both protein and mRNA expression of dopamine transporter (DAT), a key determinant of ADHD‐like phenotypes in experimental animals and humans, were significantly decreased by paternal EtOH exposure in cerebral cortex and striatum of offspring mice along with increased methylation of a CpG region of the DAT gene promoter. The increase in methylation of DAT gene promoter was also observed in the sperm of sire mice, suggesting germline changes in the epigenetic methylation signature of DAT gene by EtOH exposure. In addition, the expression of two key regulators of methylation‐dependent epigenetic regulation of functional gene expression, namely, MeCP2 and DNMT1, was markedly decreased in offspring cortex and striatum sired by EtOH‐exposed mice. These results suggest that preconceptional exposure to EtOH through the paternal route induces behavioral changes in offspring, possibly via epigenetic changes in gene expression, which is essential for the regulation of ADHD‐like behaviors.

Effects of ethanol exposure during early pregnancy in hyperactive, inattentive and impulsive behaviors and MeCP2 expression in rodent offspring.

Prenatal exposure to alcohol has consistently been associated with adverse effects on neurodevelopment, which is collectively called fetal alcohol spectrum disorder (FASD). Increasing evidence suggest that prenatal exposure to alcohol increases the risk of developing attention deficit/hyperactivity disorder-like behavior in human. In this study, we investigated the behavioral effects of prenatal exposure to EtOH in offspring mice and rats focusing on hyperactivity and impulsivity. We also examined changes in dopamine transporter and MeCP2 expression, which may underlie as a key neurobiological and epigenetic determinant in FASD and hyperactive, inattentive and impulsive behaviors. Mouse or rat offspring born from dam exposed to alcohol during pregnancy (EtOH group) showed hyper locomotive activity, attention deficit and impulsivity. EtOH group also showed increased dopamine transporter and norepinephrine transporter level compared to control group in the prefrontal cortex and striatum. Prenatal exposure to EtOH also significantly decreased the expression of MeCP2 in both prefrontal cortex and striatum. These results suggest that prenatal exposure to EtOH induces hyperactive, inattentive and impulsive behaviors in rodent offspring that might be related to global epigenetic changes as well as aberration in catecholamine neurotransmitter transporter system.

Diabetes augments cognitive dysfunction in chronic cerebral hypoperfusion by increasing neuronal cell death: implication of cilostazol for diabetes mellitus-induced dementia.

Many patients with diabetes are at increased risk of cognitive dysfunction and dementia. Diabetes mellitus is a vascular risk factor that may increase the risk of dementia through its associations with vascular dementia. We tested whether cognitive impairment could be exacerbated in combined injury using a rat model of chronic cerebral hypoperfusion with diabetes. We also determined whether a potent inhibitor of type III phosphodiesterase could prevent the cognitive decline caused by this combined injury. We used Otsuka Long-Evans Tokushima Fatty (OLETF) rats as a model of type II diabetes (T2DM) and Long-Evans Tokushima Otsuka (LETO) rats as a control. Chronic cerebral hypoperfusion was modeled by permanent bilateral common carotid artery occlusion (BCCAO). At 24weeks, the non-diabetic and T2DM rats were randomly assigned into groups for the following experiments: analysis I (1) sham non-diabetic rats (n=8); (2) hypoperfused non-diabetic rats (n=9); (3) sham T2DM rats (n=8); (4) hypoperfused T2DM rats (n=9); analysis II- (1) sham T2DM rats without treatment (n=8); (2) cilostazol-treated T2DM rats (n=8); (3) hypoperfused T2DM rats (n=9); and (4) hypoperfused T2DM rats and cilostazol treatment (n=9). The rats were orally administered cilostazol (50mg/kg) or vehicle once a day for 2weeks after 24weeks. Rats performed Morris water maze tasks, and neuronal cell death and neuroinflammation were investigated via Western blots and histological investigation. Spatial memory impairment was exacerbated synergistically in the hypoperfused T2DM group compared with the hypoperfused non-diabetic group and sham T2DBM group (P<0.05). Compared with the control group, neuronal cell death was increased in the hippocampus of the hypoperfused T2DM group. Cilostazol, a PDE-3 inhibitor, improved the memory impairments through inhibition of neuronal cell death, activation of CREB phosphorylation and BDNF expression in the hypoperfused T2DM group. Our experimental results support the hypothesis that there are deleterious interactions between chronic cerebral hypoperfusion and T2DM. That is, metabolic diseases such as diabetes may exacerbate cognitive impairment in a rat model of vascular dementia. We also suggest that surprisingly, the phosphodiesterase III inhibitor, cilostazol may be useful for the treatment of cognitive impairment in diabetes mellitus-induced dementia. In conclusion, diabetes can aggravate cognitive dysfunction in vascular dementia, and PDE-3 inhibitors, such as cilostazol, may form the basis of a novel therapeutic strategy for diabetes-associated cognitive impairment or vascular dementia.

Effects of donepezil, an acetylcholinesterase inhibitor, on neurogenesis in a rat model of vascular dementia.

Vascular dementia (VaD) is the second most common form of dementia caused by cerebrovascular disease. Several recent reports demonstrated that cholinergic deficits are implicated in the pathogenesis of VaD and that cholinergic therapies have shown improvement of cognitive function in patients with VaD. However, the precise mechanisms by which donepezil achieves its effects on VaD are not fully understood. Donepezil hydrochloride is an acetylcholinesterase inhibitor (AChEI) currently used for the symptomatic treatment of Alzheimers disease (AD). Several lines of evidence have demonstrated that AChEIs such as donepezil promote neurogenesis in the central nervous system. We investigated whether donepezil regulated hippocampal neurogenesis after bilateral common carotid artery occlusion (BCCAO) in rats, a commonly used animal model of VaD. To evaluate the effect of donepezil on neurogenesis, we orally treated rats with donepezil (10mg/kg) once a day for 3weeks, and injected BrdU over the same 3-week period to label newborn cells. The doses of donepezil that we used have been reported to activate cholinergic activity in rats. After 3weeks, a water maze task was performed on these rats to test spatial learning, and a subsequent histopathological evaluation was conducted. Donepezil improved memory impairment and increased the number of BrdU-positive cells in the dentate gyrus (DG) of BCCAO animals. These results indicated that donepezil improves cognitive function and enhances the survival of newborn neurons in the DG in our animal model of VaD, possibly by enhancing the expression of choline acetyltransferase and brain-derived neurotropic factor.

Immunization with Combined HSV-2 Glycoproteins B2:D2 Gene DNAs: Protection against Lethal Intravaginal Challenges in Mice

The immunity of a combined DNA vaccine of HSV-2 glycoproteins B2 (gB2) and D2 (gD2) genes in comparison to individual vaccines was studied with regard to protecting against the HSV infection. Two recombinant DNA vaccines of the pHS2-gB2 or pHS2-gD2 were constructed and formulated. The neutralizing antibody titers appeared higher in the B2:D2 gene cocktail-vaccinated mice than that of the individual B2 or D2 gene-vaccinated group alone, and the positive KOS control induced higher titer of the neutralizing antibody than combined or individual gene vaccines. The mock-immunized mice failed to induce enough. The ranks for the CTL activity and the protection rates against the lethal intravaginal challenge were shown as KOS>B2:D2 cocktail>D2>B2 gene vaccines. The vaginal external diseases in the B2:D2 or D-vaccinated mice were significantly reduced against the challenging dosages. The virus titers in the vaginal secretions of the vaccinated mice significantly reduced with time, and the B2:D2 gene vaccine decreased more than each individual vaccine alone. It can be concluded that the cocktailed vaccines are more effective in the humoral and cellular immune responses in the mice, and in the protection of the mice against the intravaginal challenging dosages when compared with individual gene vaccines. All the DNA vaccines failed to block the latent infection in sensory nerves.The immunity of a combined DNA vaccine of HSV-2 glycoproteins B2 (gB2) and D2 (gD2) genes in comparison to individual vaccines was studied with regard to protecting against the HSV infection. Two recombinant DNA vaccines of the pHS2-gB2 or pHS2-gD2 were constructed and formulated. The neutralizing antibody titers appeared higher in the B2:D2 gene cocktail-vaccinated mice than that of the individual B2 or D2 gene-vaccinated group alone, and the positive KOS control induced higher titer of the neutralizing antibody than combined or individual gene vaccines. The mock-immunized mice failed to induce enough. The ranks for the CTL activity and the protection rates against the lethal intravaginal challenge were shown as KOS>B2:D2 cocktail>D2>B2 gene vaccines. The vaginal external diseases in the B2:D2 or D-vaccinated mice were significantly reduced against the challenging dosages. The virus titers in the vaginal secretions of the vaccinated mice significantly reduced with time, and the B2:D2 gene vaccine decreased more than each individual vaccine alone. It can be concluded that the cocktailed vaccines are more effective in the humoral and cellular immune responses in the mice, and in the protection of the mice against the intravaginal challenging dosages when compared with individual gene vaccines. All the DNA vaccines failed to block the latent infection in sensory nerves.

Mechanism of activation of human c-KIT kinase by internal tandem duplications of the juxtamembrane domain and point mutations at aspartic acid 816

The proto-oncogene c-KIT receptor has been implicated as an essential component in the activation of leukemic cells. The internal tandem duplication (ITD) of c-KIT has also been identified as a predominant cause of acute myeloid leukemia (AML), although its role in the activation process is still unclear. To investigate the biological mechanisms of c-KIT activation, we generated a c-KIT receptor bearing two different immunological tags, HA and Flag tags. In this study, we demonstrated that the mutant (Mt)-ITD and Asp816 (D816Y) c-KIT receptors spontaneously formed dimers and that these Mt-ITD forms of c-KIT displayed high levels of phosphorylation and increased cellular tyrosine phosphorylation. The amount of wild-type homodimers increased following the addition of the c-KIT ligand, while the level of mutant homodimers was less affected by the addition of the c-KIT ligand. Furthermore, we demonstrated that Mt-ITD and activating point mutations of D816Y induced constitutive activation of c-KIT kinase in the absence of ligand in COS-1 cells. These data suggest a novel mechanism for the regulation of cell growth autonomy. Overall, our study suggests that c-KIT activation might have significant effects on hematopoietic cells and might help to improve our understanding of the pathogenesis of systemic mast cell disease, gastrointestinal stromal tumors and AML and potentially lead to the development of novel therapeutic approaches.

MicroRNA expression profiling of p-phenylenediamine treatment in human keratinocyte cell line

Abstractp-Phenylenediamine (PPD), a black dye used in hair coloring and tattoos, irritates the skin, leading to cell cycle arrest, apoptosis, and reactive oxygen species (ROS) generation. MicroRNAs (miRNAs) are well known regulators of these side effects. The aim of the present study was to evaluate PPD-induced miRNA expression profile alterations in human keratinocytes. First, we demonstrated that PPD reduced HaCaT cell viability by inducing cell cycle arrest and death, elevating cellular ROS levels and decreasing the migration rate. In addition, 67 miRNAs were upregulated by at least 5-fold in PPD-treated HaCaT cell and 17 miRNAs were downregulated by at least 5- fold in PPD-treated HaCaT cell. Using bioinformatics, we identified a relationship between PPD-mediated miRNA changes and cell death, cell cycle arrest, generation of ROS, and migration repression. Target genes of PPD-regulated miRNAs were involved in cell proliferation, apoptosis, skin development, and aging. Thus, our results establish a role for miRNAs in regulating PPD-induced cell death, cell cycle arrest, ROS generation, and repression of migration in human keratinocytes.

Proteinase 3 induces oxidative stress-mediated neuronal death in rat primary cortical neuron.

The recruitment of neutrophils into the cerebral microcirculation occurs, especially, in acute brain diseases like a focal cerebral ischemia and plays important role in pathological processes. Proteinase 3 is one of the three major proteinases expressed in neutrophils but no reports are available whether proteinase 3 can modulate neuronal survival. In this study, treatment of cultured rat primary cortical neuron with proteinase 3 induced overt reactive oxygen species production and decreased total glutathione contents as well as disruption of mitochondrial transmembrane potential. Proteinase 3 induced neuronal cell death as evidenced by MTT analysis as well as propidium iodide staining, which was prevented by pretreatment with an antioxidant, N-acetyl cysteine. Proteinase 3 increased activation of procaspase-3 and altered expression level of apoptotic regulator proteins, such as Bcl-2, Bax, and Bcl-xL. Similar to in vitro data, a direct microinjection of proteinase 3 into striatum of rat brain induced neuronal death, which was mediated by reactive oxygen species. These results suggest that proteinase 3 is new essential regulator of neuronal cell death pathway in a condition of excess neutrophil encounter in neuroinflammatory conditions.

A preliminary study of new single polymorphisms in the T helper type 17 pathway for psoriasis in the Korean population.

Psoriasis is a polygenic and multi‐factorial disease showing ethnic differences in terms of its severity and frequency. Therapies targeting interleukin (IL)−17A, IL‐17 receptor (IL‐17R) and Janus kinases (JAKs) are in clinical development for the treatment of psoriasis, and their success suggests the essential role of these molecules in psoriasis. To investigate the genetic susceptibility in T helper type 17 (Th17) cell signal transduction pathways for promoting psoriasis, we performed candidate gene and linkage disequilibrium analysis. In 208 patients and 266 normal controls, we analysed 31 single nucleotide polymorphisms in 12 genes (CAMP, IL17A, IL17F, IL17RA, IL22, JAK1, JAK2, JAK3, STAT3, TLR7, TLR9 and TYK2; abbreviations: CAMP, human cathelicidin antimicrobial peptide; STAT‐3, signal transducer and activator of transcription 3; TLR, Toll‐like receptor; TYK2, tyrosine kinase 2). Patients with psoriasis showed a strong association for IL17F rs763780 [odds ratio (OR) = 3·27, P = 0·04], which results in a histidine‐to‐arginine substitution, and JAK2 rs2274471 (OR = 2·66, P = 0·02). In addition, JAK2 rs7849191 showed a protective pattern, met the significance threshold (OR = 0·77, P = 0·05) and showed a tendency for an inverse association with the frequency of early‐onset psoriasis under age 40 years (P = 0·07). In haplotype analysis, JAK1 rs310241A/rs2780889T showed a protective effect (OR = 0·73, P = 0·03) in psoriasis. In conclusion, we report two new psoriasis‐susceptibility loci, in IL17F and JAK2, as well as a newly identified late‐onset associated protective JAK2 locus and a protective JAK1 haplotype in the Korean population.

Isolation and identification of Malassezia species from Chinese and Korean patients with seborrheic dermatitis and in vitro studies on their bioactivity on sebaceous lipids and IL-8 production.

We investigated the distribution of Malassezia yeast in 120 Chinese (20 patients from each of six cities) and 20 Korean patients with scalp seborrheic dermatitis (SD) and dandruff (SD/D) using ITS1 and ITS2 polymerase chain reaction‐restriction fragment length polymorphism. Bioactivity was studied by quantifying sebum lipid production by human primary sebocytes and inflammatory cytokine, interleukin‐8 (IL‐8) production was studied by exposing HaCaT keratinocytes with extracts of five standard Malassezia strains; M. globosa, M. restricta, M. sympodialis, M. dermatis and M. slooffiae. M. restricta and M. globosa were the most frequently encountered species from both Chinese and Korean patients. These two Malassezia species also promoted neutral lipid synthesis although the result was not statistically significant and induced significant increase in IL‐8 production among the five Malassezia species studied. The study suggests a possible role of these organisms in the pathogenesis of SD/D.