• Biomolecules & Therapeutics
• /
• v.28 no.2
• /
• pp.172-183
• /
• 2020

Phosphoinositide 3-kinase (PI3K) is considered as a promising therapeutic target for rheumatoid arthritis (RA) because of its involvement in inflammatory processes. However, limited studies have reported the involvement of PI3KC2γ in RA, and the underlying mechanism remains largely unknown. Therefore, we investigated the role of PI3KC2γ as a novel therapeutic target for RA and the effect of its selective inhibitor, PBT-6. In this study, we observed that PI3KC2γ was markedly increased in the synovial fluid and tissue as well as the PBMCs of patients with RA. PBT-6, a novel PI3KC2γ inhibitor, decreased the cell growth of TNF-mediated synovial fibroblasts and LPS-mediated macrophages. Furthermore, PBT-6 inhibited the PI3KC2γ expression and PI3K/AKT signaling pathway in both synovial fibroblasts and macrophages. In addition, PBT-6 suppressed macrophage migration via CCL2 and osteoclastogenesis. In CIA mice, it significantly inhibited the progression and development of RA by decreasing arthritis scores and paw swelling. Three-dimensional micro-computed tomography confirmed that PBT-6 enhanced the joint structures in CIA mice. Taken together, our findings suggest that PI3KC2γ is a therapeutic target for RA, and PBT-6 could be developed as a novel PI3KC2γ inhibitor to target inflammatory diseases including RA.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.27 no.6
• /
• pp.764-770
• /
• 2013

Stevia rebaudiana is a traditional herb used as a sweetener in Brazil and Paraguay as well as Korea and China. This study investigated the efficacy of Stevia rebaudiana methanol extract (SRE) to protect cells against the mitochondrial dysfunction and apoptosis in hepatocyte. To determine the effects of SRE on oxidative stress, we used the human derived hepatocyte cell line, HepG2 cell. Treatment of arachidonic acid (AA)+iron in HepG2 cells synergistically amplified cytotoxicity, as indicated by the excess reactive oxygen species (ROS) and mitochondrial permeability transition by fluorescence activated cell sorter (FACS) and immunoblot analysis. Treatment with SRE protected hepatocytes from AA+iron-induced cellular toxicity, as shown by alterations in the protein levels related with cell viability such as procaspase-3. SRE also prevented the mitochondrial dysfunction induced by AA+iron, and showed anti-oxidant effects as inhibition of $H_2O_2$ production and GSH depletion. Moreover, we measured the effects of SRE on AMP-activated protein kinase (AMPK), a key regulator in determining cell survival or death. Acetyl-CoA Carboxylase (ACC), a direct downstream target of AMPK. SRE increased phosphorylation of ACC, and prevented the inhibition of ACC phosphorylation by AA+iron. These results indicated that SRE has the ability to protect cells against AA+iron-induced $H_2O_2$ production and mitochondrial impairment, which may be mediated with AMPK-ACC pathway.

• Clinical and Experimental Pediatrics
• /
• v.55 no.9
• /
• pp.350-353
• /
• 2012

An 18-year-old boy was admitted with chest discomfort, nausea, and dyspnea at rest. At the age of 3 years, he underwent muscle biopsy and dystrophin gene analysis owing to an enlarged calf muscle and elevated serum kinase level (6,378 U/L) without overt weakness; based on the results, Becker muscular dystrophy (BMD) was diagnosed. The dystrophin gene showed deletion of exons 45 to 49. He remained ambulant and could step upstairs without significant difficulties. A chest roentgenogram showed cardiomegaly (cardiothoracic ratio, 54%), and his electrocardiogram (ECG) showed abnormal ST-T wave, biatrial enlargement, and left ventricular hypertrophy. The 2-dimensional and M-mode ECGs showed a severely dilated left ventricular cavity with diffuse hypokinesis. The systolic indices were reduced, including fractional shortening (9%) and ejection fraction (19%). Despite receiving intensive medical treatment, he died from congestive heart failure 5 months after the initial cardiac symptoms. We report a case of BMD with early-onset dilated cardiomyopathy associated with deletion of exons 45 to 49. Early cardiomyopathy can occur in BMD patients with certain genotypes; therefore, careful follow-up is required even in patients with mild phenotypes of BMD.

• The Korean Journal of Physiology and Pharmacology
• /
• v.8 no.4
• /
• pp.227-235
• /
• 2004

The aim of the present study was to examine the effect of leptin on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Leptin $(1{\sim}100\;ng/ml)$, when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced a dose-dependently the secretory responses of CA evoked by ACh $(5.32{\times}10^{-3}\;M)$, DMPP $(10^{-4}\;M)$ and McN-A-343 $(10^{-4}\;M)$, although it alone has weak effect on CA secretion. However, it did not affect the CA secretion evoked by excess $K^+\;(5.6{\times}10^{-2}\;M)$. Leptin alone produced a weak secretory response of the CA. Moreover, leptin (10 ng/ml) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase. However, in the presence of U0126 $(1\;{\mu}M)$, an inhibitor of mitogen-activated protein kinase (MAPK), leptin no longer enhanced the CA secretion evoked by ACh and DMPP. Furthermore, in the presence of anti-leptin (10 ng/ml), an antagonist of Ob receptor, leptin (10 ng/ml) also no longer potentiated the CA secretory responses evoked by DMPP and Bay-K-8644. Collectively, these experimental results suggest that leptin enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors), but does not that by membrane depolarization. It seems that this enhanced effect of leptin may be mediated by activation of U0126-sensitive MAPK through the leptin receptors, which is probably relevant to the activation of the dihydropyridine L-type $Ca^{2+}$ channels located on the rat adrenomedullary chromaffin cells.

• The Korean Journal of Physiology and Pharmacology
• /
• v.13 no.6
• /
• pp.491-496
• /
• 2009

Skeletal muscle atrophy is a common phenomenon during the prolonged muscle disuse caused by cast immobilization, extended aging states, bed rest, space flight, or other factors. However, the cellular mechanisms of the atrophic process are poorly understood. In this study, we investigated the involvement of mitogen-activated protein kinase (MAPK) in the expression of muscle-specific RING finger 1 (MuRF1) during atrophy of the rat gastrocnemius muscle. Histological analysis revealed that cast immobilization induced the atrophy of the gastrocnemius muscle, with diminution of muscle weight and cross-sectional area after 14 days. Cast immobilization significantly elevated the expression of MuRF1 and the phosphorylation of p38 MAPK. The starvation of L6 rat skeletal myoblasts under serum-free conditions induced the phosphorylation of p38 MAPK and the characteristics typical of cast-immobilized gastrocnemius muscle. The expression of MuRF1 was also elevated in serum-starved L6 myoblasts, but was significantly attenuated by SB203580, an inhibitor of p38 MAPK. Changes in the sizes of L6 myoblasts in response to starvation were also reversed by their transfection with MuRF1 small interfering RNA or treatment with SB203580. From these results, we suggest that the expression of MuRF1 in cast-immobilized atrophy is regulated by p38 MAPK in rat gastrocnemius muscles.

• The Korean Journal of Physiology and Pharmacology
• /
• v.17 no.4
• /
• pp.283-289
• /
• 2013

This study was designed to evaluate the protective effect of Korean red ginseng (KRG) against ischemia/reperfusion (I/R) injury in isolated guinea pig heart. KRG has been shown to possess various ginsenosides, which are the major components of Panax ginseng. These components are known naturally occurring compounds with beneficial effects and free radical scavenging activity. The heart was induced to ischemia for 60 min, followed by 120 min reperfusion. The hearts were randomly allocated into five groups (n=8 for each group): normal control (N/C), KRG control, I/R control, 250 mg/kg KRG group and 500 mg/kg KRG group. KRG significantly increased hemodynamics parameters such as aortic flow, coronary flow and cardiac output. Moreover, KRG significantly increased left ventricular systolic pressure (LVSP), the maximal rate of contraction (+dP/$dt_{max}$) and maximal rate of relaxation (-dP/$dt_{max}$). Also, treatment of KRG ameliorated electrocardiographic index such as the QRS, QT and RR intervals. Moreover, KRG significantly suppressed the lactate dehydrogenase, creatine kinase-MB fraction and cardiac troponin I and ameliorated the oxidative stress markers such as malondialdehyde and glutathione. KRG was standardized through ultra performance liquid chromatograph analysis for its major ginsenosides. Taken together, KRG has been shown to prevent cardiac injury by normalizing the biochemical and oxidative stress.

• Korean Journal of Bronchoesophagology
• /
• v.16 no.1
• /
• pp.39-46
• /
• 2010

Background and Objectives Various tumor markers have been studied in an attempt to evaluate and decide the optimal treatment of the patients with head and neek squamous cell carcinoma (HNSCC). A nuclear antigen Ki-67 is a proliferative marker of tumor cells in all phases of cell cycle except G0. c-met gene, the tyrosine kinase receptor for hepatocyte growth tactor, may play various roles in malignant transformation. The authors evaluated the prognostic significance of Ki-67 and c-Met in surgical specimens of HNSCC to determine the relationship with the various clinicopathological characteristics. Materials and Methods Formatin-fixed paraffin-embedded surgical specimens were obtained from 54 patients with HNSCC. Ki-67 and c-Met expressions were analyzed by immunohistochemical staning and were compared with the clinicopathological characteristics such as, pathologic differentiation, tumor stage, clinical stage and lymph node metastasis. Results Ki-67 and c-Met over-expression was detected in 66.7% and 90.7% in HNSCC. There was positive correlation of increased expression of Ki-67 with tumor stage. and clinical stage, increased expression of e-Met with tumor stage, clinical stage, and nodal status. The expression of c-Met had a significant positive relationship with Ki-67 index (p<0.05). Conclusion Therefore, Ki-67 and c-Met are useful markers of tumor progression, aggressiveness and prognosis in HNSCC.

• Journal of Veterinary Clinics
• /
• v.34 no.6
• /
• pp.441-444
• /
• 2017

A 15-year-old spayed female Miniature Schnauzer was presented for unilateral foreleg lameness and pain. On physical examination, left elbow joint swelling and stiffness were identified. On a computed tomography (CT) scan, a periosteal reaction of the left humerus from the distal metaphysis to the epiphysis and cortical destruction of the medial condyle was observed. Based on blood tests, histopathology, and immunohistochemistry, it was concluded as a skeletal histiocytic sarcoma. Since the patient's pain was not controlled despite application of a fentanyl patch, a left forelimb amputation was decided upon as part of the palliative therapy. Metronomic chemotherapy with toceranib phosphate and pamidronate was initiated. Toceranib was administered for 3 months without the development of any adverse effects except mild neutropenia. However, 3 months after initiating treatment, the toceranib was discontinued due to moderate gastrointestinal disturbances. Over the next 2 months, a left mandibular bone mass and cortical bone destruction in the bilateral tibia and tarsal joint were identified on CT. The patient became unwilling to eat and was noted to have severe skeletal pain. The anorexia and lethargy were progressively worsening and the owner decided to euthanize the patient. A necropsy was performed and the patient was definitively diagnosed with disseminated histiocytic sarcoma based on histopathologic and immunohistochemical analyses. This report describes a Miniature Schnauzer dog with DHS managed with surgical removal and metronomic chemotherapy with toceranib that survived with an improved quality of life for 7 months.

• Molecules and Cells
• /
• v.38 no.7
• /
• pp.604-609
• /
• 2015

The active metabolite of vitamin D such as $1{\alpha}$,25-dihydroxyvitamin ($D_3(1{\alpha},25(OH)_2D_3)$ is a well-known key regulatory factor in bone metabolism. However, little is known about the potential of vitamin D as an odontogenic inducer in human dental pulp cells (HDPCs) in vitro. The purpose of this study was to evaluate the effect of vitamin $D_3$ metabolite, $1{\alpha},25(OH)_2D_3$, on odontoblastic differentiation in HDPCs. HDPCs extracted from maxillary supernumerary incisors and third molars were directly cultured with $1{\alpha},25(OH)_2D_3$ in the absence of differentiation-inducing factors. Treatment of HDPCs with $1{\alpha},25(OH)_2D_3$ at a concentration of 10 nM or 100 nM significantly upregulated the expression of dentin sialophosphoprotein (DSPP) and dentin matrix protein1 (DMP1), the odontogenesis-related genes. Also, $1{\alpha},25(OH)_2D_3$ enhanced the alkaline phosphatase (ALP) activity and mineralization in HDPCs. In addition, $1{\alpha},25(OH)_2D_3$ induced activation of extracellular signal-regulated kinases (ERKs), whereas the ERK inhibitor U0126 ameliorated the upregulation of DSPP and DMP1 and reduced the mineralization enhanced by $1{\alpha},25(OH)_2D_3$. These results demonstrated that $1{\alpha},25(OH)_2D_3$ promoted odontoblastic differentiation of HDPCs via modulating ERK activation.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.28 no.1
• /
• pp.41-52
• /
• 2015

Objective : This study investigated the inhibitory mechanism of the hypopigmentating effects on ethanol extract of Rosae rugosae Flos (ERR) that has not yet been examined. Methods : We analyzed the anti-melanogenic effects of ethanol extracts from Rosae rugosae Flos by tyrosinase activity, melanin contents. We also examined protein expression levels of tyrosinase, TRP-1, TRP-2, MITF and ERK by western blot analysis in melanoma cells. Results : In this investigation, ERR effectively reduced ${\alpha}$-MSH-stimulated melanin synthesis by suppressing expression of tyrosinase and tyrosinase-related protein-1 (TRP-1). On the other hand, the expression of tyrosinase-related protein-2 (TRP-2) were not affected by treatment with ERR. ERR inhibited the expression of microphthalmia-associated transcription factor (MITF) as a key transcription factor for tyrosinase expression regulating melanogenesis. The upstream signaling pathway including cAMP response element-binding protein (CREB) and MAPKs were also inhibited by ERR. Pretreatment with PD98059, ERK inhibitor, attenuated the inhibitory effect of ERR on ${\alpha}$-MSH-induced tyrosinase activity. Conclusions : Our study suggested that the anti-melanogenic activity of ERR is correlated with the suppression of tyrosinase gene through CREB/MITF/ERK pathway.