• The Korean Journal of Physiology and Pharmacology
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• 제25권6호
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• pp.585-592
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• 2021

Cisplatin has been reported to cause side effects such as muscle wasting in humans and rodents. The physiological mechanisms involved in preventing muscle wasting, such as the regulation of AKT, PGC1-α, and autophagy-related factor FOXO3a by MuRF 1 and Atrogin-1, remain unclear following different types of exercise and in various skeletal muscle types. Eight-week-old male Wistar rats (n = 34) were assigned to one of four groups: control (CON, n = 6), cisplatin injection (1 mg/kg) without exercise (CC, n = 8), cisplatin (1 mg/kg) + resistance exercise (CRE, n = 9) group, and cisplatin (1 mg/kg) + aerobic exercise (CAE, n = 11). The CRE group performed progressive ladder exercise (starting with 10% of body weight on a 1-m ladder with 2-cm-interval grids, at 85°) for 8 weeks. The CAE group exercised by treadmill running (20 m/min for 60 min daily, 4 times/week) for 8 weeks. Compared with the CC group, the levels of the autophagy-related factors BNIP3, Beclin 1, LC3-II/I ratio, p62, and FOXO3a in the gastrocnemius and soleus muscles were significantly decreased in the CRE and CAE groups. The CRE and CAE groups further showed significantly decreased MuRF 1 and Atrogin-1 levels and increased phosphorylation of AKT, FOXO3a, and PGC1-α. These results suggest that both ladder and aerobic exercise directly affected muscle wasting by modulating the AKT/PGC1-α/FOXO3a signaling pathways regardless of the skeletal muscle type.

• The Korean Journal of Physiology and Pharmacology
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• 제25권4호
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• pp.341-354
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• 2021

Cardamonin (CARD) is a chalconoid with anti-inflammatory and antioxidant properties, and it is present in several plants. We sought to explore whether CARD exerts any positive effects against hyperglycemia-induced testicular dysfunction caused by type 2 diabetes and aimed to identify its possible intracellular pathways. Adult male rats were subdivided into six groups: control, CARD, diabetic (DM), DM + glibenclamide (GLIB), DM + CARD and DM + GLIB + CARD. Type 2 DM induced a significant increase in blood glucose and insulin resistance, along with diminished serum insulin, testosterone and gonadotropins levels, which were associated with the impairment of key testicular androgenic enzymes and cellular redox balance. Administration of CARD at a dose of 80 mg/kg for 4 weeks effectively normalized all of these alterations, and the improvement was confirmed by epididymal sperm analysis. After treatment with CARD, the pathological changes in spermatogenic tubules were markedly improved. Significantly, CARD upregulated testicular glucose transporter-8 (GLUT-8) expression and had inhibitory effects on elevated autophagy markers and caspase-3 immunoreactive cells. Furthermore, our results revealed that CARD was able to attenuate damage via activation of Nrf2 through the p62-dependent degradation of testicular anti-Kelch-like ECH-associated protein-1 (Keap-1). In conclusion, this study suggests that CARD provides protection against diabetic stress-mediated testicular damage. The use of CARD with conventional anti-diabetic therapy was associated with improved efficacy compared with conventional therapy alone.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.33-33
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• 2019

The AKT signaling pathway is a highly regulated cell signaling system that forms a network with other cell signaling pathways. Hence, the AKT signaling pathway mediates several important cellular functions that include cell survival, proliferation, cell migration, and et cetera. Irregularities that led overactive AKT signaling have been linked to many diseases such as cancer and metabolic-associated diseases. Hence, modulating the overactive AKT signaling pathway via inhibitor is a tantalizing prospect for treatment of cancer and metabolic-associated diseases. Two inhibitors of the AKT signaling pathway will be presented in this symposium: 1) Bisleuconothine A (BisA), a bisindole alkaloid that inhibit autophagy and 2) Ceramicine B (CerB), a limonoid that inhibit adipogenesis. The first topic is on a bisindole alkaloid, BisA and its mechanism in inducing autophagosome formation in lung cancer cell line, A549.(1) Since most autophagy inducing agents generally induce apoptosis, we found that BisA does not induce apoptosis even in high dose. BisA up-regulation of LC3 lipidation is achieved through mTOR inactivation. The phosphorylation of PRAS40, a mTOR repressor was suppressed by BisA. This observation suggested that BisA inactivates mTOR via suppression of PRAS40 phosphorylation. Interestingly, the phosphorylation of AKT, an upstream regulator of PRAS40 phosphorylation was also down-regulated by BisA. These findings suggested that Bis-A induces autophagosomes formation by interfering with the AKT-mTOR signaling pathway. The second topic is on CerB and its mechanism in inhibiting adipogenesis in preadipocytes cell line, MC3T3-G2/PA6.(2,3) CerB inhibits the phosphorylation of protein kinase B (AKT) at the Thr308 position but not the Ser473. Consequently, the phosphorylation of FOXO3 which is located downstream of AKT is also inhibited. Considering that FOXO3 is an important regulator of PPARγ which is a key factor in adipogenesis, CerB may inhibit adipogenesis via the AKT-FOXO3 signaling pathway. Taken together, both BisA and CerB highlighted the potential of AKT signaling pathway modulation as an approach to induce autophagy and inhibit the formation of fat cells, respectively.

• 융합정보논문지
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• 제11권2호
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• pp.201-210
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• 2021

본 연구는 메밀 추출물과 비텍신을 이용하여 UVB 손상 개선에 대한 효과를 알아보기 위해 Microarray 분석, 세포의 증식, 세포 상처 회복, 세포주기, 마이크로파지의 생성 양상, 단백질 분석 등을 실시하였다. Microarray 분석 결과는 DRAM1, Atg2a 및 Atg13 유전자에서 UVB에 의해 증가 된 양상을 메밀 에탄올추출물과 비텍신에서 감소시켰다. 세포의 증식, 상처 회복, 주기 및 마이크로파지 양상에서는 메밀 에탄올추출물과 비텍신에서 정상 세포와 유사하게 개선되었으며, 단백질 분석에서 DRAM1, Beclin-1 및 LC3 I/II 모두 비텍신 처리군에서 감소하였고, p-mTOR 및 Survivin은 모두 증가 되었다. UVB에 의한 손상에서 메밀 에탄올추출물과 비텍신은 DRAM1, Atg2a 및 Atg13을 같이 컨트롤 하고 세포 증식, 상처 회복 및 주기를 정상으로 회복하며 UVB에 의한 세포 노화 발생원인 중 하나인 오토파지를 조절하여 세포의 사멸억제 및 재생하므로 기능성 화장품 성분으로 활용가능할 것으로 사료 된다.

• Biomolecules & Therapeutics
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• 제29권2호
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• pp.220-226
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• 2021

The role of particulate matter (PM) in health problems including cardiovascular diseases (CVD) and pneumonia is becoming increasingly clear. Polycyclic aromatic hydrocarbons, major components of PM, bind to aryl hydrocarbon receptor (AhRs) and promote the expression of CYP1A1 through the AhR pathway in keratinocytes. Activation of AhRs in skin cells is associated with cell differentiation in keratinocytes and inflammation, resulting in dermatological lesions. Oleanolic acid, a natural component of L. lucidum, also has anti-inflammation, anticancer, and antioxidant characteristics. Previously, we found that PM10 induced the AhR signaling pathway and autophagy process in keratinocytes. Here, we investigated the effects of oleanolic acid on PM10-induced skin aging. We observed that oleanolic acid inhibits PM10-induced CYP1A1 and decreases the increase of tumor necrosis factor-alpha and interleukin 6 induced by PM10. A supernatant derived from keratinocytes cotreated with oleanolic acid and PM10 inhibited the release of matrix metalloproteinase 1 in dermal fibroblasts. Also, the AhR-mediated autophagy disruption was recovered by oleanolic acid. Thus, oleanolic acid may be a potential treatment for addressing PM10-induced skin aging.

• Molecules and Cells
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• 제45권4호
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• pp.257-272
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• 2022

In addition to inducing apoptosis, caspase inhibition contributes to necroptosis and/or autophagy depending on the cell type and cellular context. In macrophages, necroptosis can be induced by co-treatment with Toll-like receptor (TLR) ligands (lipopolysaccharide [LPS] for TLR4 and polyinosinic-polycytidylic acid [poly I:C] for TLR3) and a cell-permeable pan-caspase inhibitor zVAD. Here, we elucidated the signaling pathways and molecular mechanisms of cell death. We showed that LPS/zVAD- and poly I:C/zVAD-induced cell death in bone marrow-derived macrophages (BMDMs) was inhibited by receptor-interacting protein kinase 1 (RIP1) inhibitor necrostatin-1 and autophagy inhibitor 3-methyladenine. Electron microscopic images displayed autophagosome/autolysosomes, and immunoblotting data revealed increased LC3II expression. Although zVAD did not affect LPS- or poly I:C-induced activation of IKK, JNK, and p38, it enhanced IRF3 and STAT1 activation as well as type I interferon (IFN) expression. In addition, zVAD inhibited ERK and Akt phosphorylation induced by LPS and poly I:C. Of note, zVAD-induced enhancement of the IRF3/IFN/STAT1 axis was abolished by necrostatin-1, while zVAD-induced inhibition of ERK and Akt was not. Our data further support the involvement of autocrine IFNs action in reactive oxygen species (ROS)-dependent necroptosis, LPS/zVAD-elicited ROS production was inhibited by necrostatin-1, neutralizing antibody of IFN receptor (IFNR) and JAK inhibitor AZD1480. Accordingly, both cell death and ROS production induced by TLR ligands plus zVAD were abrogated in STAT1 knockout macrophages. We conclude that enhanced TRIF-RIP1-dependent autocrine action of IFNβ, rather than inhibition of ERK or Akt, is involved in TLRs/zVAD-induced autophagic and necroptotic cell death via the JAK/STAT1/ROS pathway.

• BMB Reports
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• 제55권7호
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• pp.354-359
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• 2022

MitoNEET, a mitochondrial outer membrane protein containing the Asn-Glu-Glu-Thr (NEET) sequence, controls the formation of intermitochondrial junctions and confers autophagy resistance. Moreover, mitoNEET as a mitochondrial substrate undergoes ubiquitination by activated Parkin during the initiation of mitophagy. Therefore, mitoNEET is linked to the regulation of autophagy and mitophagy. Mitophagy is the selective removal of the damaged or unnecessary mitochondria, which is crucial to sustaining mitochondrial quality control. In numerous human diseases, the accumulation of damaged mitochondria by impaired mitophagy has been observed. However, the therapeutic strategy targeting of mitoNEET as a mitophagy-enhancing mediator requires further research. Herein, we confirmed that mitophagy is indeed activated by mitoNEET inhibition. CCCP (carbonyl cyanide m-chlorophenyl hydrazone), which leads to mitochondrial depolarization, induces mitochondrial dysfunction and superoxide production. This, in turn, contributes to the induction of mitophagy; mitoNEET protein levels were initially increased before an increase in LC3-II protein following CCCP treatment. Pharmacological inhibition of mitoNEET using mitoNEET Ligand-1 (NL-1) promoted accumulation of Pink1 and Parkin, which are mitophagy-associated proteins, and activation of mitochondria-lysosome crosstalk, in comparison to CCCP alone. Inhibition of mitoNEET using NL-1, or mitoNEET shRNA transfected into RAW264.7 cells, abrogated CCCP-induced ROS and mitochondrial cell death; additionally, it activated the expression of PGC-1α and SOD2, regulators of oxidative metabolism. In particular, the increase in PGC-1α, which is a major regulator of mitochondrial biogenesis, promotes mitochondrial quality control. These results indicated that mitoNEET is a potential therapeutic target in numerous human diseases to enhance mitophagy and protect cells by maintaining a network of healthy mitochondria.

• Journal of Ginseng Research
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• 제46권1호
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• pp.79-90
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• 2022

Background: Herbal medicines are popular approaches to capably prevent and treat obesity and its related diseases. Excessive exposure to dietary lipids causes oxidative stress and inflammation, which possibly induces cellular senescence and contribute the damaging effects in brain. The potential roles of selective enhanced ginsenoside in regulating high fat diet (HFD)-induced brain damage remain unknown. Methods: The protection function of Ginsenoside F1-enhanced mixture (SGB121) was evaluated by in vivo and in vitro experiments. Human primary astrocytes and SH-SY5Y cells were treated with palmitic acid conjugated Bovine Serum Albumin, and the effects of SGB121 were determined by MTT and lipid uptake assays. For in vivo tests, C57BL/6J mice were fed with high fat diet for 3 months with or without SGB121 administration. Thereafter, immunohistochemistry, western blot, PCR and ELISA assays were conducted with brain tissues. Results and conclusion: SGB121 selectively suppressed HFD-induced oxidative stress and cellular senescence in brain, and reduced subsequent inflammation responses manifested by abrogated secretion of IL-6, IL-1β and TNFα via NF-κB signaling pathway. Interestingly, SGB121 protects against HFD-induced damage by improving mitophagy and endoplasmic reticulum-stress associated autophagy flux and inhibiting apoptosis. In addition, SGB121 regulates lipid uptake and accumulation by FATP4 and PPARα. SGB121 significantly abates excessively phosphorylated tau protein in the cortex and GFAP activation in corpus callosum. Together, our results suggest that SGB121 is able to favor the resistance of brain to HFD-induced damage, therefore provide explicit evidence of the potential to be a functional food.

• The Korean Journal of Physiology and Pharmacology
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• 제27권4호
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• pp.345-356
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• 2023

This study aimed to assess the effects of exogenous hydrogen sulfide (H₂S) on abdominal aorta coarctation (AAC) induced myocardial fibrosis (MF) and autophagy in rats. Forty-four Sprague-Dawley rats were randomly divided into control group, AAC group, AAC + H₂S group, and H₂S control group. After a model of rats with AAC was built surgically, AAC + H₂S group and H₂S group were injected intraperitoneally with H₂S (100 µmol/kg) daily. The rats in the control group and the AAC group were injected with the same amount of PBS. We observed that H₂S can improve left ventricular function and the deposition of myocardial collagen fibers, inhibit pyroptosis, down-regulate the expression of P-eif2α in myocardial tissue, and inhibit cell autophagy by activating the phosphatidylinositol 3-kinase (PI3K)/AKT1 signaling pathway (p < 0.05). In addition, angiotensin II (1 µM) H9c2 cardiomyocytes were injured in vitro experiments, and it was also observed that pyroptosis was inhibited after H₂S (400 µmol/kg) intervention, the expression of P-eif2α in cardiomyocytes was significantly down-regulated, and the PI3K/AKT1 signaling pathway was activated at the same time. Therefore, increasing the expression of P-eif2α reverses the activation of the PI3K/AKT1 signaling pathway by H₂S. In conclusion, these findings suggest that exogenous H₂S can ameliorate MF in rats with AAC by inhibiting pyroptosis, and the mechanism may be associated with inhibiting the phosphorylation of eif2α and activating the PI3K/AKT1 signaling pathway to inhibit excessive cell autophagy.

• Biomolecules & Therapeutics
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• 제32권1호
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• pp.162-169
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• 2024

Particulate matter (PM) constitutes a hazardous blend of organic and inorganic particles that poses health risks. Inhalation of fine airborne PM with a diameter of ≤ 2.5 ㎛ (PM_2.5) can lead to significant lung impairments. (+)-afzelechin (AZC), a natural compound sourced from Bergenia ligulata, boasts a range of attributes, including antioxidant, antimicrobial, anticancer, and cardiovascular effects. However, knowledge about the therapeutic potential of AZC for patients with PM_2.5-induced lung injuries remains limited. Thus, in this study, we investigated the protective attributes of AZC against lung damage caused by PM_2.5 exposure. AZC was administered to the mice 30 min after intratracheal instillation of PM_2.5. Various parameters, such as changes in lung tissue wet/dry (W/D) weight ratio, total protein/total cell ratio, lymphocyte counts, levels of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), vascular permeability, and histology, were evaluated in mice exposed to PM_2.5. Data demonstrated that AZC mitigated lung damage, reduced W/D weight ratio, and curbed hyperpermeability induced by PM_2.5 exposure. Furthermore, AZC effectively lowered plasma levels of inflammatory cytokines produced by PM_2.5 exposure. It reduced the total protein concentration in BALF and successfully alleviated PM_2.5-induced lymphocytosis. Additionally, AZC substantially diminished the expression levels of Toll-like receptors 4 (TLR4), MyD88, and autophagy-related proteins LC3 II and Beclin 1. In contrast, it elevated the protein phosphorylation of the mammalian target of rapamycin (mTOR). Consequently, the anti-inflammatory attribute of AZC positions it as a promising therapeutic agent for mitigating PM_2.5-induced lung injuries by modulating the TLR4-MyD88 and mTOR-autophagy pathways.