The Protective Role of Celastrol in Renal Ischemia-Reperfusion Injury by Activating Nrf2/HO-1, PI3K/AKT Signaling Pathways, Modulating NF-κb Signaling Pathways, and Inhibiting ERK Phosphorylation

The impact of PPAR-γ/Nrf-2/HO-1, NF-κB/IL-6/ Keap-1, and Bcl-2/caspase-3/ATG-5 pathways in mitigation of DOX-induced cardiotoxicity in an animal model: The potential cardioprotective role of oxyresveratrol and/or dapagliflozin

Antioxidants given concurrently with chemotherapy offer an effective strategy for reducing the negative effects of the drug. One remaining obstacle to the use of doxorubicin (DOX) in chemotherapy is cardiotoxicity. Using vitamin E (Vit. E) as a reference standard, our study focuses on the potential preventive benefits of oxyresveratrol (ORES) and/or dapagliflozin (DAPA) against DOX-induced cardiac injury. Acute cardiotoxicity was noticed after a single intravenous injection of a male rat's tail vein with 10 mg/kg of DOX. Oral doses of ORES (80 mg/kg), DAPA (10 mg/kg), and Vit. E (1 g/kg) were given, respectively. Pretreatment of animals with Vit. E, ORES and/or DAPA revealed a considerable alleviation of heart damage, as evidenced by histopathological change mitigation and a notable drop in serum AST, LDH, CK, CK-MB, and cardiac contents of MDA and NO2-. Also, serum TAC, tissue GSH, and SOD showed substantial increases. Additionally, tissue caspase-3, serum IL-6, and TNF-α were considerably reduced. Moreover, a downregulation in cardiac gene expression of ATG-5, Keap-1, and NF-κB in addition to an upregulation of Bcl-2 gene expression and HO-1, Nrf-2, and PPAR-γ protein expression clearly appeared. Ultimately, ORES and/or DAPA have an optimistic preventive action against severe heart deterioration caused by DOX.

Celastrol alleviates airway hyperresponsiveness and inflammation in obese asthma through mediation of alveolar macrophage polarization

Obese asthma is a unique asthma phenotype that decreases sensitivity to inhaled corticosteroids, and currently lacks efficient therapeutic medication. Celastrol, a powerful bioactive substance obtained naturally from the roots of Tripterygium wilfordii, has been reported to possess the potential effect of weight loss in obese individuals. However, its role in the treatment of obese asthma is not fully elucidated. In the present study, diet-induced obesity (DIO) mice were used with or without ovalbumin (OVA) sensitization, the therapeutic effects of celastrol on airway hyperresponsiveness (AHR) and airway inflammation were examined. We found celastrol significantly decreased methacholine-induced AHR in obese asthma, as well as reducing the infiltration of inflammatory cells and goblet cell hyperplasia in the airways. This effect was likely due to the inhibition of M1-type alveolar macrophages (AMs) polarization and the promotion of M2-type macrophage polarization. In vitro, celastrol yielded equivalent outcomes in Lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells, featuring a reduction in the expression of M1 macrophage makers (iNOS, IL-1β, TNF-α) and heightened M2 macrophage makers (Arg-1, IL-10). Mechanistically, the PI3K/AKT signaling pathway has been implicated in these processes. In conclusion, we demonstrated that celastrol assisted in mitigating various parameters of obese asthma by regulating the balance of M1/M2 AMs polarization.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery

BACKGROUND

Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system.

PURPOSE

To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis.

METHODS

First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol.

RESULTS

Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI.

CONCLUSION

Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

Human Wharton's jelly-derived mesenchymal stromal stem cells preconditioned with valproic acid promote cell migration and reduce renal inflammation in ischemia/reperfusion injury by activating the AKT/P13K and SDF1/CXCR4 pathways

OBJECTIVE

To determine whether WJ-MSCs pretreated with VPA would enhance their migration to improve functional recovery of renal IRI in rats.

METHODS

150 Sprague-Dawley rats were distributed into 5 groups; Sham, IRI, WJ-MSC, VPA, and WJ-MSCs + VPA. 10 rats were sacrificed after 3, 5, and 7 days. Role of WJ-MSCs pretreated with VPA was evaluated by assessment of renal function, antioxidant enzymes together with renal histopathological and immunohistopathological analyses and finally by molecular studies.

RESULTS

WJ-MSCs and VPA significantly improved renal function and increased antioxidants compared to IRI group. Regarding gene expression, WJ-MSCs and VPA decreased BAX and TGF-β1, up-regulated Akt, PI3K, BCL2, SDF1α, and CXCR4 related to IRI. Additionally, WJ-MSCs pretreated with VPA improved the measured parameters more than either treatment alone.

CONCLUSION

WJ-MSCs isolated from the umbilical cord and pretreated with VPA defended the kidney against IRI by more easily homing to the site of injury.

Loss of SAV1 in Kidney Proximal Tubule Induces Maladaptive Repair after Ischemia and Reperfusion Injury

Kidney ischemia and reperfusion injury (IRI) is a significant contributor to acute kidney injury (AKI), characterized by tubular injury and kidney dysfunction. Salvador family WW domain containing protein 1 (SAV1) is a key component of the Hippo pathway and plays a crucial role in the regulation of organ size and tissue regeneration. However, whether SAV1 plays a role in kidney IRI is not investigated. In this study, we investigated the role of SAV1 in kidney injury and regeneration following IRI. A proximal tubule-specific knockout of SAV1 in kidneys (SAV1ptKO) was generated, and wild-type and SAV1ptKO mice underwent kidney IRI or sham operation. Plasma creatinine and blood urea nitrogen were measured to assess kidney function. Histological studies, including periodic acid-Schiff staining and immunohistochemistry, were conducted to assess tubular injury, SAV1 expression, and cell proliferation. Western blot analysis was employed to assess the Hippo pathway-related and proliferation-related proteins. SAV1 exhibited faint expression in the proximal tubules and was predominantly expressed in the connecting tubule to the collecting duct. At 48 h after IRI, SAV1ptKO mice continued to exhibit severe kidney dysfunction, compared to attenuated kidney dysfunction in wild-type mice. Consistent with the functional data, severe tubular damage induced by kidney IRI in the cortex was significantly decreased in wild-type mice at 48 h after IRI but not in SAV1ptKO mice. Furthermore, 48 h after IRI, the number of Ki67-positive cells in the cortex was significantly higher in wild-type mice than SAV1ptKO mice. After IRI, activation and expression of Hippo pathway-related proteins were enhanced, with no significant differences observed between wild-type and SAV1ptKO mice. Notably, at 48 h after IRI, protein kinase B activation (AKT) was significantly enhanced in SAV1ptKO mice compared to wild-type mice. This study demonstrates that SAV1 deficiency in the kidney proximal tubule worsens the injury and delays kidney regeneration after IRI, potentially through the overactivation of AKT.

Celastrol inhibits necroptosis by attenuating the RIPK1/RIPK3/MLKL pathway and confers protection against acute pancreatitis in mice

Necroptosis is a necrotic form of regulated cell death, which is primarily mediated by the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) pathway in a caspase-independent manner. Necroptosis has been found to occur in virtually all tissues and diseases evaluated, including pancreatitis. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii (thunder god vine), possesses potent anti-inflammatory and anti-oxidative activities. Yet, it is unclear whether celastrol has any effects on necroptosis and necroptotic-related diseases. Here we showed that celastrol significantly suppressed necroptosis induced by lipopolysaccharide (LPS) plus pan-caspase inhibitor (IDN-6556) or by tumor-necrosis factor-α in combination with LCL-161 (Smac mimetic) and IDN-6556 (TSI). In these in vitro cellular models, celastrol inhibited the phosphorylation of RIPK1, RIPK3, and MLKL and the formation of necrosome during necroptotic induction, suggesting its possible action on upstream signaling of the necroptotic pathway. Consistent with the known role of mitochondrial dysfunction in necroptosis, we found that celastrol significantly rescued TSI-induced loss of mitochondrial membrane potential. TSI-induced intracellular and mitochondrial reactive oxygen species (mtROS), which are involved in the autophosphorylation of RIPK1 and recruitment of RIPK3, were significantly attenuated by celastrol. Moreover, in a mouse model of acute pancreatitis that is associated with necroptosis, celastrol administration significantly reduced the severity of caerulein-induced acute pancreatitis accompanied by decreased phosphorylation of MLKL in pancreatic tissues. Collectively, celastrol can attenuate the activation of RIPK1/RIPK3/MLKL signaling likely by attenuating mtROS production, thereby inhibiting necroptosis and conferring protection against caerulein-induced pancreatitis in mice.

Celastrol alleviates oxidative stress induced by multi-walled carbon nanotubes through the Keap1/Nrf2/HO-1 signaling pathway

Multi-walled carbon nanotubes (MWCNTs) mainly induce oxidative stress through the overproduction of reactive oxygen species (ROS), which can lead to cytotoxicity. Celastrol, a plant-derived compound, can exert antioxidant effects by reducing ROS production. Our results indicated that exposure to MWCNTs decreased cell viability and increased ROS production. Nrf2 knockdown (kd) led to increased ROS production and enhanced MWCNT-induced cytotoxicity. Keap1-kd led to decreased ROS production and attenuated cytotoxicity. Treatment with celastrol significantly decreased ROS production and promoted Keap1 protein degradation through the lysosomal pathway, thereby enhancing the translocation of Nrf2 from the cytoplasm to the nucleus and increasing HO-1 expression. The in vivo results showed that celastrol could alleviate the inflammatory damage of lung tissues, increase the levels of the antioxidants, GSH and SOD, as well as promote the expression of the antioxidant protein, HO-1 in MWCNT-treated mice. Celastrol can alleviate MWCNT-induced oxidative stress through the Keap1/Nrf2/HO-1 signaling pathway.

In Silico Analysis of Ferroptosis-Related Genes and Its Implication in Drug Prediction against Fluorosis

Fluorosis is a serious global public health problem. Interestingly, so far, there is no specific drug treatment for the treatment of fluorosis. In this paper, the potential mechanisms of 35 ferroptosis-related genes in U87 glial cells exposed to fluoride were explored by bioinformatics methods. Significantly, these genes are involved in oxidative stress, ferroptosis, and decanoate CoA ligase activity. Ten pivotal genes were found by the Maximal Clique Centrality (MCC) algorithm. Furthermore, according to the Connectivity Map (CMap) and the Comparative Toxicogenomics Database (CTD), 10 possible drugs for fluorosis were predicted and screened, and a drug target ferroptosis-related gene network was constructed. Molecular docking was used to study the interaction between small molecule compounds and target proteins. Molecular dynamics (MD) simulation results show that the structure of the Celestrol-HMOX1 composite is stable and the docking effect is the best. In general, Celastrol and LDN-193189 may target ferroptosis-related genes to alleviate the symptoms of fluorosis, which may be effective candidate drugs for the treatment of fluorosis.

A molecular network-based pharmacological study on the protective effect of Panax notoginseng rhizomes against renal ischemia-reperfusion injury

Objective: We aimed to explore the protective effect of Panax notoginseng rhizomes (PNR) on renal ischemia and reperfusion injury (RIRI) and the underlying molecular network mechanism based on network pharmacology and combined systemic experimental validation. Methods: A bilateral RIRI model was established, and Cr, SCr, and BUN levels were detected. Then, the PNR was pretreated 1 week before the RIRI model was prepared. To determine the effects of the PNR in RIRI, histopathological damage and the effect of PNRs to the kidney was assessed, using TTC, HE, and TUNEL staining. Furthermore, the underlying network pharmacology mechanism was detected by screening drug-disease intersection targets from PPI protein interactions and GO and KEGG analysis, and the hub genes were screened for molecular docking based on the Degree value. Finally, the expression of hub genes in kidney tissues was verified by qPCR, and the protein expression of related genes was further detected by Western blot (WB). Results: PNR pretreatment could effectively increase Cr level, decrease SCr and BUN levels, reduce renal infarct areas and renal tubular cell injury areas, and inhibit renal cell apoptosis. By using network pharmacology combined with bioinformatics, we screened co-targets both Panax notoginseng (Sanchi) and RIRI, acquired ten hub genes, and successfully performed molecular docking. Of these, pretreatment with the PNR reduced the mRNA levels of IL6 and MMP9 at postoperative day 1 and TP53 at postoperative day 7, and the protein expression of MMP9 at postoperative day 1 in IRI rats. These results showed that the PNR could decrease kidney pathological injury in IRI rats and inhibit apoptotic reaction and cell inflammation so as to improve renal injury effectively, and the core network mechanism is involved in the inhibition of MMP9, TP53, and IL-6. Conclusion: The PNR has a marked protective effect for RIRI, and the underlying mechanism is involved in inhibiting the expression of MMP9, TP53, and IL-6. This striking discovery not only provides fruitful evidence for the protective effect of the PNR in RIRI rats but also provides a novel mechanic explanation.

Nuclear factor Nrf2 promotes glycosidase OGG1 expression by activating the AKT pathway to enhance leukemia cell resistance to cytarabine

Chemotherapy resistance is the dominant challenge in the treatment of acute myeloid leukemia (AML). Nuclear factor E2-related factor 2 (Nrf2) exerts a vital function in drug resistance of many tumors. Nevertheless, the potential molecular mechanism of Nrf2 regulating the base excision repair pathway that mediates AML chemotherapy resistance remains unclear. Here, in clinical samples, we found that the high expression of Nrf2 and base excision repair pathway gene encoding 8-hydroxyguanine DNA glycosidase (OGG1) was associated with AML disease progression. In vitro, Nrf2 and OGG1 were highly expressed in drug-resistant leukemia cells. Upregulation of Nrf2 in leukemia cells by lentivirus transfection could decrease the sensitivity of leukemia cells to cytarabine, whereas downregulation of Nrf2 in drug-resistant cells could enhance leukemia cell chemosensitivity. Meanwhile, we found that Nrf2 could positively regulate OGG1 expression in leukemia cells. Our chromatin immunoprecipitation assay revealed that Nrf2 could bind to the promoter of OGG1. Furthermore, the use of OGG1 inhibitor TH5487 could partially reverse the inhibitory effect of upregulated Nrf2 on leukemia cell apoptosis. In vivo, downregulation of Nrf2 could increase the sensitivity of leukemia cell to cytarabine and decrease OGG1 expression. Mechanistically, Nrf2-OGG1 axis-mediated AML resistance might be achieved by activating the AKT signaling pathway to regulate downstream apoptotic proteins. Thus, this study reveals a novel mechanism of Nrf2-promoting drug resistance in leukemia, which may provide a potential therapeutic target for the treatment of drug-resistant/refractory leukemia.

Role of PI3K/Akt-Mediated Nrf2/HO-1 Signaling Pathway in Resveratrol Alleviation of Zearalenone-Induced Oxidative Stress and Apoptosis in TM4 Cells

Zearalenone (ZEA) is a common mycotoxin that induces oxidative stress (OS) and affects the male reproductive system in animals. Resveratrol (RSV) has good antioxidant activity and can activate nuclear factor erythroid 2-related factor (Nrf2) to protect cells through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. The objective of this study was to investigate the protective effect and the mechanism of RSV on OS and apoptosis in TM4 cells induced by ZEA. Prior to being exposed to ZEA, TM4 cells were pretreated with RSV or the PI3K/Akt inhibitor LY294002. Cell viability was measured by Cell Counting Kit-8 (CCK-8) assays. Flow cytometry was used to determine the level of apoptosis and intracellular reactive oxygen species (ROS). The expression of poly ADP-ribose polymerase (PARP), caspase-3, BCL2-associated X (Bax)/B-cell lymphoma-2 (Bcl-2), and PI3K/Akt-mediated Nrf2/heme oxygenase 1 (HO-1) signaling pathway-related proteins was evaluated by Western blotting. Nrf2 siRNA transfection and LY294002 treatment were used to investigate the role of the Nrf2/HO-1 and PI3K/Akt signaling pathways in RSV alleviation of ZEA-induced OS. The results showed that pretreatment with RSV significantly reduced the expression of apoptosis-related proteins and increased cell viability. Catalase (CAT) activity and glutathione (GSH) levels were also increased, whereas malondialdehyde (MDA) and ROS levels decreased (p < 0.05). RSV also upregulated Akt phosphorylation, Nrf2 nuclear translocation, and HO-1 expression under conditions of OS (p < 0.05). Transfection with Nrf2 siRNA abolished the protective effects of RSV against ZEA-induced cytotoxicity (p < 0.05), ROS accumulation (p < 0.05), and apoptosis (p < 0.05). LY294002 completely blocked the RSV-mediated increase in Nrf2 nuclear translocation (p < 0.05), HO-1 expression (p < 0.05), and cytoprotective activity (p < 0.05). Collectively, the above findings indicate that RSV can protect against ZEA-induced OS and apoptosis in TM4 cells by PI3K/Akt-mediated activation of the Nrf2/HO-1 signaling pathway.