1.Effect of Kaempferol on Modulation of Vascular Contractility Mainly through PKC and CPI-17 Inactivation
Hyuk-Jun YOON ; Heui Woong MOON ; Young Sil MIN ; Fanxue JIN ; Joon Seok BANG ; Uy Dong SOHN ; Hyun Dong JE
Biomolecules & Therapeutics 2024;32(3):361-367
In this study, we investigated the efficacy of kaempferol (a flavonoid found in plants and plant-derived foods such as kale, beans, tea, spinach and broccoli) on vascular contractibility and aimed to clarify the detailed mechanism underlying the relaxation. Isometric contractions of divested muscles were stored and linked with western blot analysis which was carried out to estimate the phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) and phosphorylation-dependent inhibitory protein for myosin phosphatase (CPI-17) and to estimate the effect of kaempferol on the RhoA/ROCK/CPI-17 pathway. Kaempferol conspicuously impeded phorbol ester-, fluoride- and a thromboxane mimetic-derived contractions regardless of endothelial nitric oxide synthesis, indicating its direct effect on smooth muscles. It also conspicuously impeded the fluoride-derived elevation in phospho-MYPT1 rather than phospho-CPI-17 levels and phorbol 12,13-dibutyrate-derived increase in phospho-CPI-17 and phospho-ERK1/2 levels, suggesting the depression of PKC and MEK activities and subsequent phosphorylation of CPI-17 and ERK1/2. Taken together, these outcomes suggest that kaempferol-derived relaxation incorporates myosin phosphatase retrieval and calcium desensitization, which appear to be modulated by CPI-17 dephosphorylation mainly through PKC inactivation.
2.The Effect of Luteolin on the Modulation of Vascular Contractility via ROCK and CPI-17 Inactivation
Hyuk-Jun YOON ; Dae Hong KANG ; Fanxue JIN ; Joon Seok BANG ; Uy Dong SOHN ; Hyun Dong JE
Biomolecules & Therapeutics 2023;31(2):193-199
In this investigation, we made a study of the efficacy of luteolin (a flavonoid found in plants such as vegetables, herbs and fruits) on vascular contractibility and to elucidate the mechanism underlying the relaxation. Isometric contractions of denuded muscles were stored and combined with western blot analysis which was conducted to assess the phosphorylation of myosin phosphatase targeting subunit 1 (MYPT1) and phosphorylation-dependent inhibitory protein for myosin phosphatase (CPI-17) and to examine the effect of luteolin on the RhoA/ROCK/CPI-17 pathway. Luteolin significantly alleviated phorbol ester-, fluoride- and thromboxane mimetic-elicited contractions regardless of endothelial nitric oxide synthesis, implying its direct effect on smooth muscle. It also significantly alleviated the fluoride-elicited elevation in pCPI-17 and pMYPT1 levels and phorbol 12,13-dibutyrate-elicited in-crease in pERK1/2 level, suggesting depression of ROCK and PKC/MEK activity and ensuing phosphorylation of MYPT1, CPI-17 and ERK1/2. Taken together, these results suggest that luteolin-elicited relaxation includes myosin phosphatase reactivation and calcium desensitization, which seems to be arbitrated by CPI-17 dephosphorylation via ROCK/PKC inhibition.
3.Benzyl Isothiocyanate-Induced Cytotoxicity via the Inhibition of Autophagy and Lysosomal Function in AGS Cells
Wah Wah PO ; Won Seok CHOI ; Tin Myo KHING ; Ji-Yun LEE ; Jong Hyuk LEE ; Joon Seok BANG ; Young Sil MIN ; Ji Hoon JEONG ; Uy Dong SOHN
Biomolecules & Therapeutics 2022;30(4):348-359
Gastric adenocarcinoma is among the top causes of cancer-related death and is one of the most commonly diagnosed carcinomas worldwide. Benzyl isothiocyanate (BITC) has been reported to inhibit the gastric cancer metastasis. In our previous study, BITC induced apoptosis in AGS cells. The purpose of the present study was to investigate the effect of BITC on autophagy mechanism in AGS cells. First, the AGS cells were treated with 5, 10, or 15 μM BITC for 24 h, followed by an analysis of the autophagy mechanism. The expression level of autophagy proteins involved in different steps of autophagy, such as LC3B, p62/SQSTM1, Atg5-Atg12, Beclin1, p-mTOR/mTOR ratio, and class III PI3K was measured in the BITC-treated cells. Lysosomal function was investigated using cathepsin activity and Bafilomycin A1, an autophagy degradation stage inhibitor. Methods including qPCR, western blotting, and immunocytochemistry were employed to detect the protein expression levels. Acridine orange staining and omnicathepsin assay were conducted to analyze the lysosomal function. siRNA transfection was performed to knock down the LC3B gene. BITC reduced the level of autophagy protein such as Beclin 1, class III PI3K, and Atg5-Atg12. BITC also induced lysosomal dysfunction which was shown as reducing cathepsin activity, protein level of cathepsin, and enlargement of acidic vesicle. Overall, the results showed that the BITC-induced AGS cell death mechanism also comprises the inhibition of the cytoprotective autophagy at both initiation and degradation steps.
4.The Effect of Galangin on the Regulation of Vascular Contractility via the Holoenzyme Reactivation Suppressing ROCK/CPI-17 rather than PKC/CPI-17
Hyuk-Jun YOON ; Won Pill JUNG ; Young Sil MIN ; Fanxue JIN ; Joon Seok BANG ; Uy Dong SOHN ; Hyun Dong JE
Biomolecules & Therapeutics 2022;30(2):145-150
In this study, we investigated the influence of galangin on vascular contractibility and to determine the mechanism underlying the relaxation. Isometric contractions of denuded aortic muscles were recorded and combined with western blot analysis which was performed to measure the phosphorylation of phosphorylation-dependent inhibitory protein of myosin phosphatase (CPI-17) and myosin phosphatase targeting subunit 1 (MYPT1) and to evaluate the effect of galangin on the RhoA/ROCK/CPI-17 pathway.Galangin significantly inhibited phorbol ester-, fluoride- and thromboxane mimetic-induced vasoconstrictions regardless of endothelial nitric oxide synthesis, suggesting its direct effect on vascular smooth muscle. Galangin significantly inhibited the fluoridedependent increase in pMYPT1 and pCPI-17 levels and phorbol 12,13-dibutyrate-dependent increase in pERK1/2 level, suggesting repression of ROCK and MEK activity and subsequent phosphorylation of MYPT1, CPI-17 and ERK1/2. Taken together, these results suggest that galangin-induced relaxation involves myosin phosphatase reactivation and calcium desensitization, which appears to be mediated by CPI-17 dephosphorylation via not PKC but ROCK inactivation.
5.Autophagy and Digestive Disorders: Advances in Understanding and Therapeutic Approaches
Wynn THEIN ; Wah Wah PO ; Won Seok CHOI ; Uy Dong SOHN
Biomolecules & Therapeutics 2021;29(4):353-364
The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.
6.Effects of the Combination of Evogliptin and Leucine on Insulin Resistance and Hepatic Steatosis in High-Fat Diet-Fed Mice
Chang Yell SHIN ; Hak Yeong LEE ; Gil Hyung KIM ; Sun Young PARK ; Won Seok CHOI ; Uy Dong SOHN
Biomolecules & Therapeutics 2021;29(4):419-426
In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branchedchain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.
7.Autophagy and Digestive Disorders: Advances in Understanding and Therapeutic Approaches
Wynn THEIN ; Wah Wah PO ; Won Seok CHOI ; Uy Dong SOHN
Biomolecules & Therapeutics 2021;29(4):353-364
The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.
8.Effects of the Combination of Evogliptin and Leucine on Insulin Resistance and Hepatic Steatosis in High-Fat Diet-Fed Mice
Chang Yell SHIN ; Hak Yeong LEE ; Gil Hyung KIM ; Sun Young PARK ; Won Seok CHOI ; Uy Dong SOHN
Biomolecules & Therapeutics 2021;29(4):419-426
In this study, we aimed to investigate the effects of 8 weeks of treatment with a combination of evogliptin and leucine, a branchedchain amino acid, in mice with high-fat diet (HFD)-induced diabetes. Treatment with evogliptin alone or in combination with leucine reduced the body weight of the mice, compared to the case for those from the HFD control group. Long-term treatment with evogliptin alone or in combination with leucine resulted in a significant reduction in glucose intolerance; however, leucine alone did not affect postprandial glucose control, compared to the case for the mice from the HFD control group. Furthermore, the combination of evogliptin and leucine prevented HFD-induced insulin resistance, which was associated with improved homeostasis model assessment for insulin resistance, accompanied by markedly reduced liver fat deposition, hepatic triglyceride content, and plasma alanine aminotransferase levels. The combination of evogliptin and leucine increased the gene expression levels of hepatic peroxisome proliferator-activated receptor alpha, whereas those of the sterol regulatory element-binding protein 1 and stearoyl-CoA desaturase 1 were not altered, compared to the case in the HFD-fed mice (p<0.05). Thus, our results suggest that the combination of evogliptin and leucine may be beneficial for treating patients with type 2 diabetes and hepatic steatosis; however, further studies are needed to delineate the molecular mechanisms underlying the action of this combination.
9.Improved motility in the gastrointestinal tract of a postoperative ileus rat model with ilaprazole
Geon Min KIM ; Hee Ju SOHN ; Won Seok CHOI ; Uy Dong SOHN
The Korean Journal of Physiology and Pharmacology 2021;25(6):507-515
Postoperative ileus (POI), a symptom that occurs after abdominal surgery, reduces gastrointestinal motility. Although its mechanism is unclear, POI symptoms are known to be caused by inflammation 6 to 72 h after surgery. As proton pump inhibitors exhibit protective effect against acute inflammation, the purpose of this study was to determine the effect of ilaprazole on a POI rat model. POI was induced in rats by abdominal surgery. Rats were divided into six groups: control: normal rat + 0.5% CMC-Na, vehicle: POI rat + 0.5% CMC-Na, mosapride: POI rat + mosapride 2 mg/kg, ilaprazole 1 mg/kg: POI rat + ilaprazole 1 mg/kg, ilaprazole 3 mg/kg: POI rat + ilaprazole 3 mg/kg, and ilaprazole 10 mg/kg: POI rat + ilaprazole 10 mg/kg. Gastrointestinal motility was confirmed by measuring gastric emptying (GE) and gastrointestinal transit (GIT). In the small intestine, inflammation was confirmed by measuring TNF-α and IL-1β; oxidative stress was confirmed by SOD, GSH, and MDA levels; and histological changes were observed by H&E staining. Based on the findings, GE and GIT were decreased in the vehicle group and improved in the ilaprazole 10 mg/kg group. In the ilaprazole 10 mg/kg group, TNF-α and IL-1β levels were decreased, SOD and GSH levels were increased, and MDA levels were decreased. Histological damage was also reduced in the ilaprazole-treated groups. These findings suggest that ilaprazole prevents the decrease in gastrointestinal motility, a major symptom of postoperative ileus, and reduces inflammation and oxidative stress.
10.The hepato-protective effect of eupatilin on an alcoholic liver disease model of rats
Hak Yeong LEE ; Yoonjin NAM ; Won Seok CHOI ; Tae Wook KIM ; Jaehwi LEE ; Uy Dong SOHN
The Korean Journal of Physiology and Pharmacology 2020;24(5):385-394
Eupatilin is known to possess anti-apoptotic, anti-oxidative, and antiinflammatoryproperties. We report here that eupatilin has a protective effect onthe ethanol-induced injury in rats. Sprague–Dawley rats were divided into 6 groups:control, vehicle, silymarin, eupatilin 10 mg/kg, eupatilin 30 mg/kg, and eupatilin 100mg/kg. Plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase(ALT) were analyzed to determine the extent of liver damage. Total cholesterol(TC) and triglycerides (TG) were analyzed to determine the level of liver steatosis.Malondialdehyde level, superoxide dismutase (SOD) activity, and glutathione (GSH)level were analyzed to determine the extent of oxidative stress. Tumor necrosis factor(TNF)- and interleukin (IL)-1 were quantified to verify the degree of inflammation.Based on our findings, chronic alcohol treatment significantly changed the serumindexes and liver indicators of the model rats, which were significantly improved byeupatilin treatment. Rats in the eupatilin-treatment group showed reduced levelsof AST, ALT, TG, TC, TNF-, and IL-1, increased SOD activity and GSH levels, and improvedoverall physiology compared to the alcoholic liver disease model rats. H&Estaining also verified the eupatilin-mediated improvement in liver injury. In conclusion,eupatilin inhibits alcohol-induced liver injury via its antioxidant and anti-inflammatoryeffects.

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