Joo-Ho Chung

Estrogen receptor-α gene haplotype is associated with primary knee osteoarthritis in Korean population

Estrogen and estrogen receptors (ERs) are known to play important roles in the pathophysiology of osteoarthritis (OA). To investigate ER-α gene polymorphisms for its associations with primary knee OA, we conducted a case–control association study in patients with primary knee OA (n = 151) and healthy individuals (n = 397) in the Korean population. Haplotyping analysis was used to determine the relationship between three polymorphisms in the ER-α gene (intron 1 T/C, intron 1 A/G and exon 8 G/A) and primary knee OA. Genotypes of the ER-α gene polymorphism were determined by PCR followed by restriction enzyme digestion (PvuII for intron 1 T/C, XbaI for intron 1 A/G, and BtgI for exon 8 G/A polymorphism). There was no significant difference between primary knee OA patients and healthy control individuals in the distribution of any of the genotypes evaluated. However, we found that the allele frequency for the exon 8 G/A BtgI polymorphism (codon 594) was significantly different between primary knee OA patients and control individuals (odds ratio = 1.38, 95% confidence interval = 1.01–1.88; P = 0.044). In haplotype frequency estimation analysis, there was a significant difference between primary knee OA patients and control individuals (degrees of freedom = 7, χ2 = 21.48; P = 0.003). Although the number OA patients studied is small, the present study shows that ER-α gene haplotype may be associated with primary knee OA, and genetic variations in the ER-α gene may be involved in OA.

Proteomic analysis of the neuroprotective mechanisms of acupuncture treatment in a Parkinson's disease mouse model

Acupuncture is frequently used as an alternative therapy for Parkinsons disease (PD), and it attenuates dopaminergic (DA) neurodegeneration in the substantia nigra (SN) in PD animal models. Using proteomic analysis, we investigated whether acupuncture alters protein expression in the SN to favor attenuation of neuronal degeneration. In C57BL/6 mice treated with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP, 30 mg/kg/day), intraperitoneal (i.p.) for 5 days, 2 or 100 Hz electroacupuncture (EA) was applied at the effective and specific acupoint, GB34, once a day for 12 consecutive days from the first MPTP treatment. Both treatments in MPTP mice led to restoration of behavioral impairment and rescued tyrosine hydroxylase (TH)‐positive DA neurodegeneration. Using peptide fingerprinting MS, we identified changes in 22 proteins in the SN following MPTP treatment, and nine of these proteins were normalized by EA. They were involved in cell death regulation, inflammation, or restoration from damage. The levels of cyclophilin A (CypA), which is a neuroprotective agent, were unchanged by MPTP treatment but were increased in MPTP‐EA mice. These results suggest that acupoint GB34‐specific EA changes protein expression profiles in the SN in favor of DA neuronal survival in MPTP‐treated mice, and that EA treatment may be an effective therapy for PD patients.

Melatonin suppresses NO-induced apoptosis via induction of Bcl-2 expression in PGT-β immortalized pineal cells

Abstract: In the present study, we investigated whether melatonin would prevent nitric oxide (NO)‐induced apoptotic death of PGT‐β immortalized pineal cells. To examine the protective effect of melatonin, cytotoxicity assay, DNA fragmentation analysis, caspase‐3 activity assay, and Western blotting for caspase‐3 and poly(ADP‐ribose) polymerase (PARP) were performed. Treatment of cells with S‐nitroso‐N‐acetylpenicillamine (SNAP), an NO donor, was shown to induce apoptotic cell death in a dose‐dependent manner, and pretreatment with melatonin (0.1 mm) attenuated the occurrence of NO‐induced apoptotic cell death. DNA fragmentation in response to NO was also arrested by melatonin. Caspase‐3 activity induced by NO was decreased with melatonin treatment. Furthermore, the active fragments of caspase‐3 and PARP were almost completely absent following exposure to melatonin. To elucidate the protective mechanisms of action of melatonin, Western blot analyses for Bcl‐2 expression and cytochrome c release were carried out. Pretreatment with melatonin (0.1 mm) induced the expression of Bcl‐2 and suppressed the release of cytochrome c into the cytosol, thereby arresting NO‐induced apoptotic cell death. These results suggest that the antiapoptotic effect of melatonin is associated with induction of Bcl‐2 expression in PGT‐β cells, which in turn blocks caspase‐3 activation and inhibits cytochrome c release into the cytosol.

Melatonin stimulates glucose transport via insulin receptor substrate-1/phosphatidylinositol 3-kinase pathway in C2C12 murine skeletal muscle cells

Abstract:  The prevalence of diabetes has exponentially increased in recent decades due to environmental factors such as nocturnal lifestyle and aging, both of which influence the amount of melatonin produced in the pineal gland. The present study investigated the effect of melatonin on signaling pathways of glucose transport in C2C12 mouse skeletal muscle cells. Intriguingly, treatment of C2C12 cells with melatonin (1 nm) stimulated glucose uptake twofold increase. Melatonin‐stimulated glucose transport was inhibited with co‐treatment with the melatonin receptor antagonist luzindole. Furthermore, treatment of stably over‐expressed melatonin receptor type 2B containing C2C12 myotubes with melatonin amplified glucose transport c. 13‐fold. Melatonin also increased the phosphorylation level of insulin receptor substrate‐1 (IRS‐1) and the activity of phosphoinositide 3‐kinase (PI‐3‐kinase). However, 3′,5′‐cyclic adenosine monophosphate‐activated protein kinase (AMPK), another important glucose transport stimulatory mediator via an insulin‐independent pathway, was not influenced by melatonin treatment. Activity of p38 mitogen‐activated protein kinase (MAPK), a downstream mediator of AMPK, was also not changed by melatonin. In addition, melatonin increased the expression level of forkhead box A2, which was recently discovered to regulate fatty acid oxidation and to be inhibited by insulin. In summary, melatonin stimulates glucose transport to skeletal muscle cells via IRS‐1/PI‐3‐kinase pathway, which implies, at the molecular level, its role in glucose homeostasis and possibly in diabetes. Additionally, exposure to light at night and aging, both of which lower endogenous melatonin levels may contribute to the incidence and/or development of diabetes.

Effect of human umbilical cord blood-derived mesenchymal stem cells in a cirrhotic rat model.

Background/Aim: Cirrhosis is a long‐term consequence of chronic hepatic injury and no effective therapy is currently available for this disease. Recent reports have shown that the mesenchymal stem cells (MSCs) have the capacity to differentiate into hepatocytes, and umbilical cord blood is a rich source of MSCs. Hence, we investigated the effect of infusing of human umbilical cord blood‐derived MSCs (HMSCs) in carbon tetrachloride (CCl4)‐induced cirrhosis in a rat model.

Susceptibility for ischemic stroke in Korean population is associated with polymorphisms of the interleukin-1 receptor antagonist and tumor necrosis factor-α genes, but not the interleukin-1β gene

Enhanced release of proinflammatory cytokines may contribute to the pathogenesis of ischemic stroke. Interleukin-1 receptor antagonist (IL-1Ra) is an anti-inflammatory cytokine, and tumor necrosis factor (TNF)-alpha and IL-1beta are proinflammatory cytokine. To determine the role of cytokines in genetic susceptibility to ischemic stroke, we genotyped ischemic stroke patients (n = 152) and the healthy control subjects (n = 165) for IL-1Ra, TNF-alpha and IL-1beta polymorphism by polymerase chain reaction-restriction fragment length polymorphism methods. The analysis shown the association of IL1RN*1, IL1RN*2 allele (IL1RN*1, OR=0.44, P = 0.0206 IL1RN*2, OR=2.90, P = 0.0141) and TNF1, TNF2 allele (TNF1, OR=2.16, P = 0.0225; TNF2, OR=2.16, P = 0.0225) to ischemic stroke. However, the genetic polymorphism of IL-1beta was not associated with ischemic stroke. Our results suggest that IL-1Ra and TNF-alpha gene polymorphism is associated with the susceptibility to ischemic stroke.

Naringin Protects against Rotenone-induced Apoptosis in Human Neuroblastoma SH-SY5Y Cells

Rotenone, a mitochondrial complex I inhibitor, can induce the pathological features of Parkinsons disease (PD). In the present study, naringin, a grapefruit flavonoid, inhibited rotenone-induced cell death in human neuroblastoma SH-SY5Y cells. We assessed cell death and apoptosis by measuring mitogen-activated protein kinase (MAPKs) and caspase (CASPs) activities and by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 4,6-diamidino-2-phenylindole (DAPI) staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Naringin also blocked rotenone-induced phosphorylation of Jun NH2-terminal protein kinase (JNK) and P38, and prevented changes in B-cell CLL/lymphoma 2 (BCL2) and BCL2-associated X protein (BAX) expression levels. In addition, naringin reduced the enzyme activity of caspase 3 and cleavages of caspase 9, poly (ADP-ribose) polymerase (PARP), and caspase 3. These results suggest that naringin has a neuroprotective effect on rotenone-induced cell death in human neuroblastoma SH-SY5Y cells.

Protective effect of topiramate on kainic acid–induced cell death in mice hippocampus

The protective effect of topiramate (TPM) on seizure‐induced neuronal injury is well known; however, its molecular basis has yet to be elucidated. We investigated the effect and signaling mediators of TPM on seizure‐induced hippocampal cell death in kainic acid (KA)‐treated ICR mice. KA‐induced hippocampal cell death was identified by terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling. Immunoreactivity (IR) of p‐Erk, p‐Jnk, p‐P38, and caspase‐3, and caspase‐3 activity were observed in the hippocampal region 3 h after KA (0.1 μg/5 μL, i.c.v.) administration, and/or TPM (100 mg/kg, i.p.) pretreatment. TPM attenuated seizure‐induced neuronal cell death and reduced KA‐induced p‐Erk IR in the CA3 region of the hippocampus, but did not affect p‐Jnk and p‐P38. In addition, TPM reduced caspase‐3 IR and activation by KA. KA‐induced seizures were also suppressed by TPM pretreatment. TPM inhibits seizures, and decreases Erk phosphorylation and caspase‐3 activation by KA, thereby contributing to protection from neuronal injury.

Association study between catalase gene polymorphisms and the susceptibility to vitiligo in Korean population

Abstract:  Vitiligo is an acquired pigmentary disorder characterized by well‐circumscribed depigmented patches. Autoimmune, self‐destruction, neural, and genetic theories have been proposed for the pathogenesis of vitiligo. Reactive oxygen species play an important role in the physiology of cell damage, and catalase is known to regulate oxidative stress. Reduced catalase enzyme activity and accumulation of excessive hydrogen peroxide were observed in vitiligo. To examine whether catalase gene polymorphisms are associated with vitiligo patients in Korean population, we investigated two CAT gene polymorphisms including (T/C) BstX I (A/T) Hinf I in 118 vitiligo patients and 200 healthy volunteers. The CAT gene genotype distribution and allele frequency were not significantly different between vitiligo patients and healthy controls. But, the haplotype of two polymorphisms was associated with vitiligo. This study suggests possible association between the CAT gene and the vitiligo susceptibility.

Association between IL17A/IL17RA Gene Polymorphisms and Susceptibility to Alopecia Areata in the Korean Population

Background Alopecia areata is marked by autoimmune assault on the hair follicle resulting in hair loss. T helper 17 cell subset has important roles in protecting the host against extracellular pathogens, however, also promotes inflammatory pathology in autoimmune disease, and it expresses both interleukin (IL)-17A and IL-17F, which can signal via the IL-17 receptor A. Objective To investigate the significance of IL17A and IL17RA gene polymorphisms in the susceptibility to alopecia areata. Methods We conducted case-control association study of 238 alopecia areata patients and 270 matched healthy controls. Allele frequency of total 2 single nucleotide polymorphims in the IL17A gene and 4 single nucleotide polymorphims in the IL17RA gene were studied. The statistical analyses were performed according to onset age, the presence of familyhistory, clinical subtypes, and presence of nail involvement or body hair involvement. Results One single nucleotide polymorphim (rs879577) of IL17RA gene showed significant difference between alopecia areata patients group and controls group (p= 0.0288). One single nucleotide polymorphim (rs4819554) of IL17RA gene showed significant difference between the early onset and late onset alopecia areata (p=0.0421). Conclusion IL17RA gene polymorphism might contribute to the increased susceptibility to alopecia areata in Korean population, and IL17RA gene polymorphism may be associated with onset age.