Effects of Astragaloside IV Against the TGF-β1-Induced Epithelial-to-Mesenchymal Transition in Peritoneal Mesothelial Cells by Promoting Smad 7 Expression

Background/Aims: Astragaloside (AGS) extracted from radix astragalin (Huangqi) has been considered to be beneficial to liver diseases. In this study, we examined the role played by AGS in alleviating hepatic fibrosis function via protease-activated receptor-2 (PAR2) mechanisms. We hypothesized that AGS affects PAR2 signaling pathway thereby improving hepatic function in rats with hepatic fibrosis induced by carbon tetrachloride (CCl₄). We further hypothesized that AGS attenuates impaired hepatic function evoked by CCl₄ to a greater degree in diabetic animals. Methods: ELISA and Western Blot analysis were used to examine PAR2 signaling pathway in diabetic CCl₄-rats and non-diabetic CCl₄-rats. Results: AGS inhibited the protein expression of PAR2 and its downstream pathway PKA and PKCɛ in CCl₄-rats. Notably, the effects of AGS were greater in CCl₄-rats with diabetes. AGS also significantly attenuated the CCl₄-induced upregulations of pro-inflammatory cytokines, namely interleukin-1β, interleukin-6 and tumor necrosis factor-α accompanied with decreases of collagenic parameters such as hexadecenoic acid, laminin and hydroxyproline. Additionally, AGS improved the CCl₄-induced exaggerations of liver index and functions including alanine aminotransferase, aspartate aminotransferase. Moreover, TGF-β1, a marker of hepatic fibrosis, was increased in CCl₄-rats and AGS inhibited increases in TGF-β1 induced by CCl₄. Conclusions: AGS alleviates hepatic fibrosis by inhibiting PAR2 signaling expression and its effects are largely enhanced in diabetic animals. Targeting one or more of these signaling molecules may present new opportunities for treatment and management of hepatic fibrosis; and results of our study are likely to shed light on strategies for application of AGS because it has potentially greater therapeutic effectiveness for hepatic fibrosis in diabetes.

Section: Discussionsupporting

confidence: 66%

“…Astragaloside (AGS) extracted from radix astragali has been considered to play a central role [11-15]. Thus, in this study we examined the effects of AGS on PAR2 signal pathway in rats with hepatic fibrosis induced by carbon tetrachloride (CCl 4 ).…”

Section: Introductionmentioning

confidence: 99%

Astragaloside Alleviates Hepatic Fibrosis Function via PAR2 Signaling Pathway in Diabetic Rats

Wang

Xiang

et al. 2017

“…Furthermore, TNF-α- and LPS-induced inflammatory reactions may be inhibited by AS-IV treatment via the NF-kB pathway in endothelial cells [8]. Evidence from pharmacological research and clinical practice suggests that AS-IV possesses effective anti-inflammatory properties and the ability to treat infectious diseases [9, 10]. …”

Section: Introductionmentioning

confidence: 99%

Astragaloside-IV Alleviates Heat-Induced Inflammation by Inhibiting Endoplasmic Reticulum Stress and Autophagy

Dong

Zhou

Zhang

et al. 2017

Background: Thermal injury is the main cause of pulmonary disease in stroke after burn and can be life threatening. Heat-induced inflammation is an important factor that triggers a series of induces pathological changes. However, this mechanism underlying heat-induced inflammation in thermal inhalation injury remains unclear. Studies have revealed that astragaloside-IV (AS-IV), a natural compound extracted from Astragalus membranaceus, has protective effects in inflammatory diseases. Here, we investigated whether the protective effects of AS-IV occur because of the suppression of heat-induced endoplasmic reticulum (ER) stress and excessive autophagy Methods: AS-IV was administered to Wistar rats after thermal inhalation injury and 16HBE140-cells were treated with AS-IV. TNF-α, IL-6, and IL-8 levels were determined by ELISA and real-time PCR. ER stress and autophagy were determined by western blot. Autophagic flux was measured by recording the fluorescence emission of the fusion protein mRFP-GFP-LC3 by dynamic live-cell imaging. Results: AS-IV had protective effects against heat-induced reactive oxygen species production and attenuated ER stress. AS IV alleviated heat-induced excessive autophagy in vitro and in vivo. Excessive autophagy was attenuated by the PERK inhibitor GSK2656157 and eIF2α siRNA, suggesting that heat stress-induced autophagy can activate the PERK-eIF2α pathway. Beclin 1 and Atg5 siRNAs inhibited the upregulation of the inflammatory cytokines TNF-α, IL-6, and IL-8 after heat exposure. Conclusions: Thus, AS-IV may attenuate inflammatory responses by disrupting the crosstalk between autophagy and the PERK-eIF2α pathway and may be an ideal agent for treating inflammatory pulmonary diseases.

“…As-IV is a monomer located in an extract of Astragalus membranaceus [41]. Herein, our study is the first time to report that AS-IV prevents against heat induced apoptosis in heat-induced thermal inhalation injury and elucidated the mechanisms responsible for this protective effect.…”

Section: Discussionmentioning

confidence: 84%

Astragaloside-IV Protects Against Heat-induced Apoptosis by Inhibiting Excessive Activation of Mitochondrial Ca2+ Uniporter

Dong

Zhang

Chen

et al. 2017

Background: Heat causes airway damage during inhalation injury because of bronchial epithelial cell damage. Accumulating evidence shows that mitochondrial uniporter (MCU) is involved in cell damage. We investigated the MCU activity after heat treatment and assessed whether Astragaloside-IV (AS-IV) suppresses heat-induced apoptosis in bronchial epithelial cells by inhibiting the activation of the mitochondrial Ca²⁺ uniporter (MCU), mitochondrial depolarisation and reactive oxygen species (ROS) production. Methods: The bronchial epithelial cell line 16HBE14o- was heat treated, and cell apoptosis was induced in vitro and in vivo. AS-IV was inorganically administered to Wistar rats twice a day after thermal inhalation injury, and 16HBE140- cells were treated with AS-IV after incubation at 47°C for 5 min. Protein expression was determined using Western blotting and commercial kits, apoptosis with TUNEL staining, mitochondrial channel activity by patch clamp, reactive oxygen species by MitoSOX^TM fluorescence, ATP levels and enzyme activities by commercial kits as well as mitochondrial respiration and calcium by fluorescence. Results: AS-IV markedly inhibited heat-induced apoptosis, as indicated by the increased expression of the pro-apoptotic genes Bak, Bik and Bmf and increased expression of the apoptosis markers Bax, cleaved parp, cleaved caspase3 and cytochrome C. We found that MCU activation promoted mitochondrial Ca²⁺ overload, ATP depletion, mitochondrial ROS production and cytochrome c release and rapidly induced apoptosis. However, AS-IV treatment reduced excessive MCU activation and led to resistance against mitochondrial Ca²⁺ overload and excessive cytochrome C release; these effects were blocked by the MCU activator spermine. AS-IV treatment elevated ATP production and decreased ROS activity. Conclusions: MCU plays crucial roles in heat-induced mitochondrial apoptosis in 16HBE140- cells, suggesting a potential target for AS-IV treatment.