Ginsenoside Rb3 provides protective effects against cisplatin-induced nephrotoxicity via regulation of AMPK-/mTOR-mediated autophagy and inhibition of apoptosis in vitro and in vivo

Nephroprotective effect of umbelliferone against cisplatin-induced kidney damage is mediated by regulation of NRF2, cytoglobin, SIRT1/FOXO-3, and NF- kB-p65 signaling pathways

Cisplatin (Cis) is one of the most potent and effective broad-spectrum antitumor drugs, but its use is limited due to nephrotoxicity. The current study investigated the renoprotective effect of umbelliferone (UMB) on Cis-induced nephrotoxicity in rats. Renal injury was induced by a single injection of Cis (7 mg/kg, ip). Our results exhibited that the injection of Cis significantly disrupted renal function biomarkers as well as KIM-1 expression. The expressions of TNF-α, IL-1β, NF-kB-p65, and IKKβ were elevated along with downregulation of IkBα expression. Also, Cis disrupted cellular oxidant/antioxidant balance through the reduction of glutathione (GSH), glutathione-S-transferase (GST), and superoxide dismutase (SOD) levels and elevation of malondialdehyde (MDA) content. On the contrary, the levels of renal function biomarkers, cytokines, NF-kB-p65, IkBα, IKKβ, and oxidant/antioxidant status have been improved after UMB treatment. Mechanistically, rats administered Cis only exhibited a significant decrease in NRF2 and cytoglobin expressions as well as the CREB, SIRT1, FOXO-3, and PPAR-γ genes. Treatment with UMB significantly upregulated NRF2 and cytoglobin proteins, as well as effectively increased the expression of CREB, SIRT1, FOXO-3, PPAR-γ, and NRF2 genes. Histopathological findings strongly supported our biochemical results, as evidenced by attenuation of renal hemorrhage, cast diffusion, and inflammatory cell infiltration. Interestingly, UMB significantly enhanced Cis cytotoxicity in both HL-60 and HeLa cells in a dose-dependent manner. Together, our results demonstrated that UMB can protect against Cis-induced nephrotoxicity in normal rats along with the enhancement of its in vitro antitumor activity. These findings suggested that UMB could be used as a potential adjuvant therapy in Cis chemotherapeutic protocols.

Ginsenoside Rb3 Alleviates the Toxic Effect of Cisplatin on the Kidney during Its Treatment to Oral Cancer via TGF-β-Mediated Mitochondrial Apoptosis

Objective

The research aimed to confirm the role of the transforming growth factor-β (TGF-β) in cisplatin- (CPT-) evoked kidney toxicity and elucidate the mechanism that ginsenoside Rb3 (Rb3) could alleviate the kidney toxicity by CPT during its treatment to oral cancer via TGF-β-mediated mitochondrial apoptosis.

Methods

The model of xenograft nude mice bearing oral carcinoma cells ACC83 was established and treated with CPT and/or Rb3, respectively. Bodyweights of the treated mice were weighed, and the kidney tissues were collected; following, the histopathology and the expression of TGF-β were examined using H&E staining and immunohistochemistry. Afterward, the renal cells GP-293 were treated with CPT and/or Rb3. The expression and phosphoration of TGF-β, Smad2, Smad3, Bcl-2, and Bax in GP-293 cells were detected by Western blotting. The cellular apoptosis and mitochondrial membrane potential were analyzed using flow cytometry.

Results

The xenograft nude mice exposure to CPT presented the bodyweight loss, necrotic areas, and the increased expression of TGF in kidney tissue, and Rb3 pretreatment relieved these changes evoked by CPT. In GP-293 cells, CPT administration induced the phosphorylation of Smad2 and Smad3, and Rb3 pretreatment suppressed the induced phosphorylation by CPT. Besides, flow cytometry analysis showed that Rb3 inhibited the CPT-evoked cellular apoptosis ratio and mitochondrial membrane depolarization. The Western blotting test indicated that Rb3 alleviated the cleavage of PARP, caspase 3, caspase 8, and caspase 9, the induction of Bax expression, and inhibition of Bcl-2 expression. Additionally, after treating with the TGF inhibitor of disitertide, Rb3 exhibited no alleviation effects on CPT-evoked cellular apoptosis ratio, inhibition of Bax expression, and induction of Bcl-2 expression in GP-293 cells.

Conclusion

Rb3 could alleviate CPT-evoked toxic effects on kidney cells during its treatment to oral cancer via TGF-β-mediated mitochondrial apoptosis.

AMPK/mTOR Signaling in Autophagy Regulation During Cisplatin-Induced Acute Kidney Injury

Autophagy is a conserved, multistep pathway that degrades and recycles dysfunctional organelles and macromolecules to maintain cellular homeostasis. Mammalian target of rapamycin (mTOR) and adenosine-monophosphate activated-protein kinase (AMPK) are major negative and positive regulators of autophagy, respectively. In cisplatin-induced acute kidney injury (AKI) or nephrotoxicity, autophagy is rapidly induced in renal tubular epithelial cells and acts as a cytoprotective mechanism for cell survival. Both mTOR and AMPK have been implicated in the regulation of autophagy in cisplatin-induced AKI. Targeting mTOR and/or AMPK may offer effective strategies for kidney protection during cisplatin-mediated chemotherapy.

Metformin enhances anti-cancer effects of cisplatin in meningioma through AMPK-mTOR signaling pathways

Cisplatin is currently used to treat inoperable recurrent meningiomas, but its side effects and drug resistance limit its use. Metformin has recently been identified as a chemosensitizing agent. However, the combined treatment of cisplatin and metformin in high-grade meningiomas has not been reported. Herein, our findings demonstrate metformin significantly enhanced cisplatin-induced inhibition of proliferation in meningioma cells, which was associated with the induction of G0/G1 cell cycle arrest. Additionally, metformin activated adenosine monophosphate activated protein kinase (AMPK) and repressed the mammalian target of rapamycin (mTOR) signaling pathways via an AMPK-dependent mechanism. Furthermore, our xenograft murine model confirmed that metformin enhanced cisplatin’s anti-cancer effect by upregulation of AMPK and downregulation of mTOR signaling pathways. In addition, in 63 patients with atypical meningiomas, the activation of AMPK was significantly associated with tumor recurrence and short disease-free survival (DFS). These results demonstrate metformin enhanced the anti-cancer effect of cisplatin in meningioma in vitro and in vivo, an effect mediated through the activation of AMPK and repression of mTOR signaling pathways. Our study suggests the combined treatment of metformin and cisplatin is an effective and safe treatment for high-grade meningiomas.

A meta-analysis of preclinical studies using antioxidants for the prevention of cisplatin nephrotoxicity: implications for clinical application

Cisplatin is an effective chemotherapeutic drug whose clinical use and efficacy are limited by its nephrotoxicity, which affects mainly the renal tubules and vasculature. It accumulates in proximal and distal epithelial tubule cells and causes oxidative stress-mediated cell death and malfunction. Consequently, many antioxidants have been tested for their capacity to prevent cisplatin nephrotoxicity. In this study, we made a systematic review of the literature and meta-analyzed 152 articles, which tested the nephroprotective effect of isolated compounds or mixtures of natural origin on cisplatin nephrotoxicity in preclinical models. This meta-analysis identified the most effective candidates and examined the efficacy obtained by antioxidants administered by the oral and intraperitoneal routes. By comparing with a recent, similar meta-analysis performed on clinical studies, this article identifies a disconnection between preclinical and clinical research, and contextualizes, discusses, and integrates the existing preclinical information toward the optimized selection of candidates to be further explored (clinical level). Despite proved efficacy, this article discusses the barriers limiting the clinical development of natural mixtures, such as those in extracts from Calendula officinalis flowers and Heliotropium eichwaldii roots. On the contrary, isolated compounds are more straightforward candidates, among which arjunolic acid and quercetin stand out in this meta-analysis.

Ginsenoside Rb3 Inhibits Pro-Inflammatory Cytokines via MAPK/AKT/NF-κB Pathways and Attenuates Rat Alveolar Bone Resorption in Response to Porphyromonas gingivalis LPS

Conventional treatments for chronic periodontitis are less effective in controlling inflammation and often relapse. Therefore, it is necessary to explore an immunomodulatory medication as an adjuvant. Ginsenoside Rb3 (Rb3), one of the most abundant active components of ginseng, has been found to possess anti-inflammatory and immunomodulatory properties. Here, we detected the anti-inflammatory effect of Rb3 on Porphyromonas gingivalis LPS-stimulated human periodontal ligament cells and experimental periodontitis rats for the first time. We found that the expression of pro-inflammatory mediators, including IL-1β, IL-6 and IL-8, upregulated by lipopolysaccharide (LPS) stimulation was remarkably downregulated by Rb3 treatment in a dose-dependent manner at both transcriptional and translational levels. Network pharmacological analysis of Rb3 showed that the mitogen-activated protein kinase (MAPK) signaling pathway had the highest richness and that p38, JNK, and ERK molecules were potential targets of Rb3 in humans. Western blot analysis revealed that Rb3 significantly suppressed the phosphorylation of p38 MAPK and p65 NF-κB, as well as decreased the expression of total AKT. In experimental periodontitis rat models, reductions in alveolar bone resorption and osteoclast generation were observed in the Rb3 treatment group. Thus, we can conclude that Rb3 ameliorated Porphyromonas gingivalis LPS-induced inflammation by inhibiting the MAPK/AKT/NF-κB signaling pathways and attenuated alveolar bone resorption in experimental periodontitis rats.

AMPK/mTOR/ULK1 Axis-Mediated Pathway Participates in Apoptosis and Autophagy Induction by Oridonin in Colon Cancer DLD-1 Cells

BACKGROUND

Oridonin has been demonstrated to exert strong antitumor activities in various types of human cancers. Our previous study established that oridonin induced the apoptosis of and exerted an inhibitory effect on colon cancer cells in vitro and in vivo. However, the mechanisms behind the antitumor effects of oridonin on colorectal cancer are not clearly known. This study explored whether autophagy was involved in antitumorigenesis effects caused by the usage of oridonin in colon cancer and examined whether the AMPK/mTOR/ULK1 signaling pathway was involved in this process.

METHODS

Cell viability was determined using CCK-8 assay. The distribution of cell apoptosis was evaluated using flow cytometry. RT-PCR and Western blotting analysis were conducted to identify the key target genes and proteins involved in the AMPK/mTOR cascade. AMPK siRNA was used to disturb AMPK expression. A DLD-1 cell orthotopic transplantation tumor model was established to explore the anti-cancer effects in vivo.

RESULTS

Oridonin exhibited a suppressive effect on DLD-1 cells in a concentration- and time-dependent manner. Additionally, in a dose-dependent manner, oridonin induced cell apoptosis via inducing the protein expression levels of cleaved caspase-3, cleaved PARP and stimulated autophagy by increasing protein expression levels of Becin1, LC3-II, decreasing protein expression levels of LC3-I, p62, which were respectively attenuated and elevated by autophagy inhibitor 3-MA. Furthermore, oridonin upregulated the expression level of p-AMPK and downregulated the expression levels of p-mTOR, p-ULK1 in the DLD-1 cells in a dose-dependent manner. Moreover, knockdown of AMPK by a specific siRNA reversed the expression levels of proteins involved in the AMPK/mTOR pathway, autophagy and apoptosis. In addition, outcomes from the in vivo experiments also showed that oridonin treatment significantly repressed tumorigenic growth of DLD-1 cells without any side effects, which was accompanied by the upregulation of p-AMPK, LC3-II, active caspase-3 protein expression levels and the downregulation of p-mTOR and p-ULK1 protein expression levels.

CONCLUSION

This study demonstrated that oridonin induced apoptosis and autophagy of colon cancer DLD-1 cells via regulating the AMPK/mTOR/ULK1 pathway, which indicated that oridonin may be used as a novel therapeutic intervention for patients with colorectal cancer.

Saponins derived from the stems and leaves of Panax ginseng attenuate scrotal heat-induced spermatogenic damage via inhibiting the MAPK mediated oxidative stress and apoptosis in mice

Heat stress (HS) reaction is a stress response caused by adverse conditions. Currently, the incidence of reproductive malignancies particularly in males has been constantly increasing. This work investigated the effects of saponins derived from the stems and leaves of Panax ginseng (GSLS) on testicular injury induced by scrotal hyperthermia in mice. GSLS (150, 300 mg/kg) were administered intragastrically to mice for 14 days, then exposed to a single scrotal heat treatment at 43°C for 18 min on seventh day. HS induced a significant loss of multinucleate giant cells, desquamation of germ cells in destructive seminiferous tubules. Moreover, HS reduced the serum testosterone, testicular tissue superoxide dismutase activity and glutathione (GSH) content, while significantly enhanced the production of malondialdehyde (p < .05). GSLS exhibited the protective potential against HS-induced injury not only by modulating Bcl-2 family and caspase protease family, but also by suppressing the protein levels of heme oxygenase-1 (HO-1), heat shock protein 70 (HSP70), hypoxia inducible factor-1α (HIF-1α) and activation of Mitogen-activated protein kinase (MAPK) signaling pathways (p < .05). In conclusion, we clearly demonstrated that GSLS exhibited a significant protective effect against HS-induced testicular dysfunction, mainly the inhibition of oxidative stress associated apoptosis partly via regulation of the MAPK signaling pathway.

Role of STAT3/mTOR pathway in chronic kidney injury

STAT3/mTOR pathway plays an important role in inflammation, cell growth, and proliferation. However, the role of STAT3/mTOR pathway in chronic kidney injury remains unclear. Folic acid was used to induce kidney injury C57BL/6 mouse model followed by analysis of serum creatinine, renal weight ratio changes, renal pathological changes and STAT3/mTOR pathway changes. Glomerular mesangial cells were divided into control group, model group, STAT3 inhibitor (S3I-201) group followed by analysis of cell proliferation by MTT assay, cell apoptosis by flow cytometry, formation of autophagosomes by electron microscopy, expression of STAT3/mTOR signaling proteins and autophagy proteins LC3II and p62 by Western blot, expression of E-cadherin and Vimentin by immunofluorescence. The serum creatinine and renal weight ratio was increased with obvious lesions and upregulated STAT3 and p-mTOR level. Compared with control group, the difference was statistically significant (P < 0.05). Folic acid-induced injury of mesangial cells showed inhibited cell proliferation, promoted apoptosis, increased LC3II expression, decreased p62 expression, increased autophagic vacuoles and expression of STAT3 and p-mTOR as well as decreased E-cadherin expression and increased Vimentin expression. The difference was statistically significant compared with control group (P < 0.05). All above changes were significantly reversed after treatment with STAT3 inhibitor S3I-201 (P < 0.05). Activated STAT3/mTOR pathway, enhanced autophagy, promoted apoptosis of mesangial cells and inhibited cell proliferation were found in mice with renal injury. Inhibition of STAT3/mTOR activation inhibits autophagy and cell apoptosis and promotes cell proliferation.

Role of unfolded protein response in genital malformation/damage of male mice induced by flutamide

The unfolded protein response (UPR) is one of a switch of autophagy and apoptosis, and the endoplasmic reticulum stress (ERS) which inducing UPR plays a role in the malformations caused by some genetic and environmental factors. Exposure to flutamide during pregnancy will also cause abnormalities in some male offspring reproductive organs such as cryptorchidism. In this study, after administered the pregnant mouse orally at a dose of 300 mg/kg body weight every day during gestational day (GD)12 to GD18, flutamide can not only caused hypospadias in the male mouse offspring but also damaged the morphology and function of their testis. And the expression of UPR-related genes and proteins, autophagy, apoptosis, and angiogenesis-related genes of the damaged/teratogenic testis and penis in the mice were investigated to determine the role of UPR in this model. It was found that flutamide activated maybe the Atg7-Atg3-Lc3 pathway through the UPR pathway, caused cells excessive autophagy and apoptosis, and inhibited the formation of penile and testicular blood vessels by activating UPR and affecting the messenger RNA level of vascular endothelial growth factor and hypoxia-inducible factor 1.

TIPE1-mediated autophagy suppression promotes nasopharyngeal carcinoma cell proliferation via the AMPK/mTOR signalling pathway

Recent studies have shown that tumour necrosis factor‐α–induced protein 8 like‐1(TIPE1) plays distinct roles in different cancers. TIPE1 inhibits tumour proliferation and metastasis in a variety of tumours but acts as an oncogene in cervical cancer. The role of TIPE1 in nasopharyngeal carcinoma (NPC) remains unknown. Interestingly, TIPE1 expression was remarkably increased in NPC tissue samples compared to adjacent normal nasopharyngeal epithelial tissue samples in our study. TIPE1 expression was positively correlated with that of the proliferation marker Ki67 and negatively correlated with patient lifespan. In vitro, TIPE1 inhibited autophagy and induced cell proliferation in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells. In addition, knocking down TIPE1 expression promoted autophagy and decreased proliferation, whereas overexpressing TIPE1 increased the levels of pmTOR, pS6 and P62 and decreased the level of pAMPK and the LC3B. Furthermore, the decrease in autophagy was remarkably rescued in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells treated with the AMPK activator AICAR. In addition, TIPE1 promoted tumour growth in BALB/c nude mice. Taken together, results indicate that TIPE1 promotes NPC progression by inhibiting autophagy and inducing cell proliferation via the AMPK/mTOR signalling pathway. Thus, TIPE1 could potentially be used as a valuable diagnostic and prognostic biomarker for NPC.

SPAG6 silencing induces autophagic cell death in SKM-1 cells via the AMPK/mTOR/ULK1 signaling pathway

As a member of the cancer-testis antigen family, sperm-associated antigen 6 (SPAG6) has been reported to be associated with the pathogenesis of myelodysplastic syndromes (MDS). Previous studies have demonstrated that SPAG6 is upregulated in bone marrow from patients with MDS and MDS-transformed acute myeloid leukemia and that knockdown of SPAG6 expression levels suppressed proliferation and promote apoptosis and differentiation in SKM-1 cells. However, the association between SPAG6 and autophagy in SKM-1 cells remains unclear. Hence, the aim of the present study was to investigate this association and its underlying mechanism. The present study used a short hairpin RNA (shRNA) lentivirus to silence SPAG6 expression levels in SKM-1 cells and demonstrated that SPAG6 knockdown increased autophagy and apoptosis. Furthermore, pharmacologically inhibiting autophagy with chloroquine and 3-methyladenine decreased SPAG6 knockdown-mediated apoptosis, indicating that SPAG6 knockdown-mediated autophagy promoted apoptosis in SKM-1 cells. Additionally, compared with the expression levels in negative control-shRNA lentivirus-transfected SKM-1 cells, the protein expression levels of phosphorylated AMP-activated protein kinase (p-AMPK) and phosphorylated unc-51-like autophagy activating kinase 1 (p-ULK1) were upregulated, while phosphorylated mammalian target of rapamycin (p-mTOR) protein expression was downregulated in SPAG6-shRNA lentivirus-transfected cells. Moreover, inhibiting AMPK expression levels with Compound C, a specific inhibitor of AMPK, attenuated SPAG6 knockdown-induced autophagy and apoptosis, suggesting that AMPK-mediated autophagy enhanced the pro-apoptotic effect of SPAG6 knockdown in SKM-1 cells. Taken together, the results of the present study demonstrated that SPAG6 silencing triggered autophagy via regulation of the AMPK/mTOR/ULK1 signaling pathway, which further contributed to the apoptosis of SKM-1 cells induced by SPAG6 knockdown. Thus, the current results indicate that SPAG6 may be a potential therapeutic target against MDS, and that autophagy may represent a potential mechanism for the treatment of MDS.

Red ginseng protects against cisplatin-induced intestinal toxicity by inhibiting apoptosis and autophagy via the PI3K/AKT and MAPK signaling pathways

Although growing evidence has shown that ginseng (Panax ginseng C.A. Meyer.) exerts strong protective and preventive effects on cisplatin-induced side effects, including nephrotoxicity, ototoxicity and cardiotoxicity, the ameliorative effects of ginseng on intestinal damage caused by cisplatin are unknown to date. Red ginseng (RG), a major processed product of the roots of Panax ginseng C.A. Meyer, can be used to control chemotherapy drug-induced multiple toxicity. In the present work, an animal model of cisplatin-induced intestinal injury was established to evaluate the ameliorative effects of RG and their underlying molecular mechanism for the first time. The results showed that a single cisplatin injection (20 mg kg^-1) leads to loss of body weight, shrinkage of the small intestine, and sharp increase of the intestinal function index of diamine oxidase (DAO). These symptoms were remarkably relieved after the administration of RG at 300 and 600 mg kg^-1 for 10 continuous days, respectively. In addition, RG markedly reduced the increase in malondialdehyde (MDA) levels and the consumption of superoxide dismutase (SOD) and catalase (CAT) caused by cisplatin-induced oxidative stress. Furthermore, RG pretreatment dramatically improved the cisplatin-induced apoptosis of intestinal villous cells, irregular nuclear arrangement, ablation of crypt cells, and damage to the mechanical barrier. In this study, pharmacological methods have been used to prove that RG can inhibit cisplatin intestinal toxicity by activating the PI3K/AKT signaling pathway to inhibit apoptosis and by antagonizing the MAPK-mediated autophagy pathway.

Unique Triterpenoid of Jujube Root Protects Cisplatin-induced Damage in Kidney Epithelial LLC-PK1 Cells via Autophagy Regulation

Chronic exposure to cisplatin is associated with irreversible kidney impairment. In this present study, we explored the protective effects of 3-dehydroxyceanothetric acid 2-methyl ester (3DC2ME) isolated from roots of jujube (Ziziphus jujuba, Rhamnaceae) against cisplatin-induced damage in vitro. In kidney epithelial LLC-PK1 cells, western blotting and staining with specific autophagy epifluorescent dye CytoID were used to determine the molecular pathways involving autophagy. Treatment with 3DC2ME reduced the increased Cyto-ID-stained autophagic vesicles and reversed the protein expressions of 5' AMP-activated protein kinase subunit β-1 (AMPK)/mammalian target of rapamycin (mTOR)-dependent signaling pathway in cisplatin-induced cell death. Additionally, treatment with autophagy inhibitor 3-methyladenine (3-MA) and with or without 3DC2ME attenuated the cisplatin-induced apoptosis. Although further research is necessary to substantiate the effects, we evaluated the potential mechanism of action of 3DC2ME as an adjuvant for cancer patients.

Fisetin Prevents Acetaminophen-Induced Liver Injury by Promoting Autophagy

Acetaminophen (APAP) overdose is a leading cause of drug-induced acute liver failure in clinical and hospital settings. Fisetin (FST) is a phenolic compound derived from natural products such as fruit and vegetables. Our research investigated the protective mechanisms of FST in APAP-induced hepatic injury in vitro and vivo. Assessment of mouse serum levels of alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO) activity, malondialdehyde (MDA), glutathione (GSH), and reactive oxygen species (ROS) demonstrated the protective effects of FST toward APAP-induced liver injury. FST also reversed an APAP-induced decrease in mouse L-02 cell line viability. Our results also showed that FST significantly promoted APAP-induced autophagy and inhibited inflammasome activation both in vivo and in vitro. We also found that silencing ATG5, using si-ATG5, reduced the protective effects of FST against APAP-induced hepatotoxicity and reversed the effects on autophagy. Finally, we used the autophagy inhibitor, 3-methyladenine (3-MA) to validate the involvement of autophagy in FST against APAP-induced hepatotoxicity in vitro. We demonstrated that FST prevented APAP-induced hepatotoxicity by increasing ATG5 expression, thereby promoting autophagy and inhibiting inflammasome activation.

Protective Effect of Panaxynol Isolated from Panax vietnamensis against Cisplatin-Induced Renal Damage: In Vitro and In Vivo Studies

Polyacetylenic compounds isolated from Panax species are comprised of non-polar C17 compounds, exhibiting anti-inflammatory, antitumor, and antifungal activities. Panaxynol represents the major component of the essential oils of ginseng. We investigated whether panaxynol isolated from Panax vietnamensis (Vietnamese ginseng, VG) could prevent cisplatin-induced renal damage induced in vitro and in vivo. Cisplatin-induced apoptotic cell death was observed by staining with annexin V conjugated with Alexa Fluor 488, and western blotting evaluated the molecular mechanism. Panaxynol at concentrations above 0.25 μM prevented cisplatin-induced LLC-PK1 porcine renal proximal tubular cell death. LLC-PK1 cells treated with cisplatin demonstrated an increase in apoptotic cell death, whereas pretreatment with 2 and 4 μM panaxynol decreased this effect. Cisplatin demonstrated a marked increase in the phosphorylation of c-Jun N-terminal kinase (JNK), P38, and cleaved caspase-3. However, pretreatment with 2 and 4 μM panaxynol reversed the upregulated phosphorylation of JNK, P38, and the expression of cleaved caspase-3. We confirmed that the protective effect of panaxynol isolated from P. vietnamensis in LLC-PK1 cells was at least partially mediated by reducing the cisplatin-induced apoptotic damage. In the animal study, panaxynol treatment ameliorated body weight loss and blood renal function markers and downregulated the mRNA expression of inflammatory mediators.

Supplementation of Saponins from Leaves of Panax quinquefolius Mitigates Cisplatin-Evoked Cardiotoxicity via Inhibiting Oxidative Stress-Associated Inflammation and Apoptosis in Mice

Background: Although kidney injury caused by cisplatin has attracted much attention, cisplatin-induced cardiotoxicity is elusive. Our previous studies have confirmed that saponins (ginsenosides) from Panax quinquefolius can effectively reduce acute renal injuries. Our current study aimed to identify the potential effects of saponins from leaves of P. quinquefolius (PQS) on cisplatin-evoked cardiotoxicity. Methods: Mice were intragastrically with PQS at the doses of 125 and 250 mg/kg daily for 15 days. The mice in cisplatin group and PQS + cisplatin groups received four times intraperitoneal injections of cisplatin (3 mg/kg) two days at a time from the 7th day, respectively. All mice were killed at 48 h following final cisplatin injection. Body weights, blood and organic samples were collected immediately. Results: Our results showed that cisplatin-challenged mice experienced a remarkable cardiac damage with obvious histopathological changes and elevation of lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase isoenzyme MB (CK-MB) and cardiac troponin T (cTnT) concentrations and viabilities in serum. Cisplatin also impaired antioxidative defense system in heart tissues manifested by a remarkable reduction in reduced glutathione (GSH) content and superoxide dismutase (SOD) activity, demonstrating the overproduction of reactive oxygen species (ROS) and oxidative stress. Interestingly, PQS (125 and 250 mg/kg) can attenuate cisplatin-evoked changes in the above-mentioned parameters. Additionally, PQS administration significantly alleviated the oxidation resulted from inflammatory responses and apoptosis in cardiac tissues via inhibition of overexpressions of TNF-α, IL-1β, Bax, and Bad as well as the caspase family members like caspase-3, and 8, respectively. Conclusion: Findings from our present research clearly indicated that PQS exerted significant effects on cisplatin-induced cardiotoxicity in part by inhibition of the NF-κB activity and regulation of PI3K/Akt/apoptosis mediated signaling pathways.

Molecular Interactions Between Reactive Oxygen Species and Autophagy in Kidney Disease

Reactive oxygen species (ROS) are highly reactive signaling molecules that maintain redox homeostasis in mammalian cells. Dysregulation of redox homeostasis under pathological conditions results in excessive generation of ROS, culminating in oxidative stress and the associated oxidative damage of cellular components. ROS and oxidative stress play a vital role in the pathogenesis of acute kidney injury and chronic kidney disease, and it is well documented that increased oxidative stress in patients enhances the progression of renal diseases. Oxidative stress activates autophagy, which facilitates cellular adaptation and diminishes oxidative damage by degrading and recycling intracellular oxidized and damaged macromolecules and dysfunctional organelles. In this review, we report the current understanding of the molecular regulation of autophagy in response to oxidative stress in general and in the pathogenesis of kidney diseases. We summarize how the molecular interactions between ROS and autophagy involve ROS-mediated activation of autophagy and autophagy-mediated reduction of oxidative stress. In particular, we describe how ROS impact various signaling pathways of autophagy, including mTORC1-ULK1, AMPK-mTORC1-ULK1, and Keap1-Nrf2-p62, as well as selective autophagy including mitophagy and pexophagy. Precise elucidation of the molecular mechanisms of interactions between ROS and autophagy in the pathogenesis of renal diseases may identify novel targets for development of drugs for preventing renal injury.

Ginsenoside Rb3 provides protective effects against cisplatin-induced nephrotoxicity via regulation of AMPK-/mTOR-mediated autophagy and inhibition of apoptosis in vitro and in vivo

Objectives

Based on previous reports that ginsenosides have been shown to exert better preventive effects on cisplatin‐induced kidney injury, the present work aims to evaluate the protective effects of ginsenoside Rb3 (G‐Rb3) on cisplatin‐induced renal damage and underlying mechanisms in vivo and in vitro.

Materials and methods

The protective effect of G‐Rb3 on cisplatin‐induced acute renal failure in ICR mouse model and HEK293 cell model was investigated, and the underlying possible mechanisms were also explored. For animal experiment, renal function, kidney histology, inflammation, oxidative stress, relative protein molecules involved in apoptosis and autophagy signalling pathways were assessed. In addition, rapamycin (a specific inhibitor of mTOR), compound C (a specific inhibitor of AMPK) and acetylcysteine (NAC, a specific ROS scavenger) were employed to testify the effects of AMPK/mTOR signal pathway on the protective effects of G‐Rb3 in HEK293 cells.

Results

Pre‐treatment with G‐Rb3 at doses of 10 and 20 mg/kg for ten days significantly reversed the increases in serum creatinine (CRE), blood urea nitrogen (BUN) and malondialdehyde (MDA), and decrease in glutathione (GSH) content and superoxide dismutase (SOD) activity. Histopathological examination further revealed that G‐Rb3 inhibited cisplatin‐induced nephrotoxicity. G‐Rb3 diminished cisplatin‐induced increase in protein expression levels of p62, Atg3, Atg5 and Atg7, and decrease in protein expression level of p‐mTOR and the ratio of LC3‐I/LC3‐II, indicating that G‐Rb3 suppressed cisplatin‐induced activation of autophagy. Inhibition of autophagy induced inactivation of apoptosis, which suggested that autophagy played an adverse effect on cisplatin‐evoked renal damage. Further, we found that G‐Rb3 might potentially modulate the expressions of AMPK‐related signal pathways.

Conclusions

These findings clearly suggested that G‐Rb3‐mediated alleviation of cisplatin‐induced nephrotoxicity was in part due to regulation of AMPK‐/mTOR‐mediated autophagy and inhibition of apoptosis in vitro and in vivo.