Celastrol Administration Research Articles

Neuroprotection of celastrol against postoperative cognitive dysfunction through dampening cGAS-STING signaling

Neuroinflammation is a central player in postoperative cognitive dysfunction (POCD), an intractable and highly confounding neurological complication with finite therapeutic options. Celastrol, a quinone methide triterpenoid, is a bioactive ingredient extracted from Tripterygium wilfordii with talented anti-inflammatory capacity. However, it is unclear whether celastrol can prevent anesthesia/surgery-evoked cognitive deficits in an inflammation-specific manner. The STING agonist 5,6-dimethylxanthenone-4-acetic acid (DMXAA) was used to determine whether celastrol possesses neuroprotection dependent on the STING pathway in vivo and in vitro. Isoflurane and laparotomy triggered cGAS-STING activation, caspase-3/GSDME-dependent pyroptosis, and enhanced Iba-1 immunoreactivity. Celastrol improved cognitive performance and decreased the levels of cGAS, 2′3′-cGAMP, STING, NF-κB phosphorylation, Iba-1, TNF-α, IL-6, and IFN-β. Downregulation of cleaved caspase-3 and N-GSDME was observed in the hippocampus of POCD mice and HT22 cells after celastrol administration, accompanied by limited secretion of pyroptosis-pertinent pro-inflammatory cytokines IL-1β and IL-18. DMXAA neutralized the favorable influences of celastrol on cognitive function, as confirmed by the activation of the STING/caspase-3/GSDME axis. These findings implicate celastrol as a therapeutic agent for POCD through anti-inflammation and anti-pyroptosis.

Celastrol inhibits platelet function and thrombus formation

IntroductionCelastrol is an active pentacyclic triterpenoid extracted from Tripterygium wilfordii and has anti-inflammatory and anti-tumor properties. Whether Celastrol modulates platelet function remains unknown. Our study investigated its role in platelet function and thrombosis. MethodsHuman platelets were isolated and incubated with Celastrol (0, 1, 3 and 5 μM) at 37 °C for 1 h to measure platelet aggregation, granules release, spreading, thrombin-induced clot retraction and intracellular calcium mobilization. Additionally, Celastrol (2 mg/kg) was intraperitoneally administrated into mice to evaluate hemostasis and thrombosis in vivo. ResultsCelastrol treatment significantly decreased platelet aggregation and secretion of dense or alpha granules induced by collagen-related peptide (CRP) or thrombin in a dose-dependent manner. Additionally, Celastrol-treated platelets showed a dramatically reduced spreading activity and decreased clot retraction. Moreover, Celastrol administration prolonged tail bleeding time and inhibited formation of arterial/venous thrombosis. Furthermore, Celastrol significantly reduced calcium mobilization. ConclusionCelastrol inhibits platelet function and venous/arterial thrombosis, implying that it might be utilized for treating thrombotic diseases.

Celastrol restricts experimental periodontitis related alveolar bone loss by suppressing inflammatory cytokine response.

Periodontitis is a common chronic inflammatory disease characterized by the destruction of the supporting structures of the teeth. The host defense mechanisms are responsible for inflamatuar and destructive reactions in periodontitis. Celastrol is one of the most promising components of the plant in Eastern and Southern China that has a long history of use in traditional medicine for the treatment of inflammatory conditions. The aim of this animal study was to inspect the preventive or restrictive effects of celastrol on periodontitis-related inflammatory host response and alveolar bone loss. 24 male Sprague Dawley rats were randomly assigned into 3 groups: control, experimental periodontitis (Ep), and experimental periodontitis-celastrol (Ep-Cel). Periodontitis was induced by placing ligatures sub-paramarginally around the mandibular first molars of the rats in the Ep and Ep-Cel groups and maintaining the ligatures for 15 days. For 14 days following the ligature placement, celastrol administration (1 mg/kg BW day) for the Ep-Cel group and vehicle injection for the control and Ep groups was carried out. At the end of the experiment, mandibula and gingiva samples were obtained after the euthanasia. Alveolar bone loss was measured on serial histological slices; Tumor Necrosis Factor-α and Interleukin-1β levels were measured on gingiva samples by ELISA. Systemic celastrol administration significantly restricted the alveolar bone loss that was higher in rats with periodontitis. (p < 0.05) Tumor Necrosis Factor-α and Interleukin-1β levels that were high in the gingiva of the rats with periodontitis were found significantly lower in rats administered celastrol. (p < 0.05). Celastrol restricted periodontitis-related alveolar bone loss by suppressing the inflammatory response.

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 enhances bone wound healing in rats.

Bone fracture is one of the most common injuries in the human musculoskeletal system. This study was performed to investigate the effects of celastrol on bone wound healing in rats. Bone wound models of Sprague-Dawley rats were treated with low (10 μg/kg) and high (100 μg/kg) celastrol for 14 days. Serum calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) contents, bone mechanical properties, bone mineral density (BMD), and the levels of osteogenesis-related and inflammation-related proteins were assessed at the end of the experiments. Rats feeding with celastrol grew normally as control. Compared with model, celastrol administration significantly increased fracture strength, elastic load (0.12 vs 0.16 kg/m), bending energy (11.23 vs 14.23 n x mm), and BMD (0.49 vs 0.54 g/cm3), particularly at a high dose. Serum Ca (2.2 vs 2.7 mmol/L) and ALP (217.3 vs 245.8 IU/L) contents were significantly increased after a high dose celastrol administration, although P content did not change. Western blot analyses showed that OPG (0.72 vs 1.15) and COL-1 (0.20 vs 0.42) but not RUNX2 were upregulated significantly after celastrol administration, and IL-1α (0.82 vs 0.37), IL-6 (0.62 vs 0.28), MCP-1(0.68 vs 0.18), and VEGF (0.62 vs 0.42) were significantly downregulated, while IFN-γ was upregulated (0.29 vs 0.46). Our data demonstrate that celastrol effectively promotes the healing of bone wound in rats and may be further explored as a therapeutic agent to treat bone fracture.

Induction of the ER stress response in NRVMs is linked to cardiotoxicity caused by celastrol.

Celastrol is a quinone methide triterpenoid extracted from the root bark of Tripterygium wilfordii Hook F, and it exhibits extensive biological activities such as anti-cancer effects. However, narrow therapeutic window together with undesired side effects limit its clinical application. In this study, we explore celastrol's cardiotoxicity using the methods of histology and cell biology. The results show that celastrol administration dose-dependently induces cardiac dysfunction in mice as manifested by left ventricular dilation, myocardial interstitial fibrosis, and cardiomyocyte hypertrophy. Exposure to celastrol greatly decreases neonatal rat ventricular myocyte (NRVM) viability and promotes its apoptosis. More importantly, we demonstrate that celastrol exerts its pro-apoptotic effects through endoplasmic reticulum (ER) stress and unfolded protein response. Furthermore, siRNA targeting C/EBP homologous protein, a pivotal component of ER stress-mediated apoptosis, effectively prevents the pro-apoptotic effect of celastrol. Taken together, our results demonstrate the potential cardiotoxicity of celastrol and a direct involvement of ER stress in the celastrol-induced apoptosis of NRVMs. Thus, we recommend careful evaluation of celastrol's cardiovascular effects when using it in the clinic.

Celastrol alleviates high-fat diet-induced obesity via enhanced muscle glucose utilization and mitochondrial oxidative metabolism-mediated upregulation of pyruvate dehydrogenase complex

Celastrol, a natural triterpene from the Tripterygium wilfordii has been demonstrated to possess attributive properties to attenuate various animal models of obesity-associated conditions. The present study aimed to elucidate the putative targets of celastrol on intracellular glucose utilization and mitochondrial oxidative metabolism in the isolated quadriceps skeletal muscle of high-fat diet (HFD)-induced obese male C57BL6/J mice. Here we showed that celastrol remarkably attenuated obesity and insulin resistance through improvement of systemic glucose tolerance and insulin sensitivity. Enhanced mRNA transcription factors of key rate-limiting glycolytic and TCA cycle enzymes were observed following celastrol administration. The metabolic profiling revealed profound changes induced by celastrol administration on several key metabolites of glycolysis and tricarboxylic acid (TCA) cycle including glucose-1-phosphate, pyruvate, citrate, α-ketoglutarate, succinate and fumarate. Celastrol effectively increased mitochondrial oxidative functions via increased pyruvate dehydrogenase complex (PDC) activity and downregulated pyruvate dehydrogenase kinase 4 (PDK4) expressions. Enhanced succinate dehydrogenase (SDH) activity was noticed following celastrol co-supplementation, leading to a steady establishment of the electrochemical gradient across mitochondrial membrane for ATP production and mitochondrial biogenesis. In conclusion, the current findings accentuate the therapeutic potential of celastrol against HFD-induced obese mice via enhanced glucose utilization and mitochondrial oxidative metabolism-mediated upregulation of PDC activity in the skeletal muscle.

Celastrol Alleviates Autoimmune Hepatitis Through the PI3K/AKT Signaling Pathway Based on Network Pharmacology and Experiments.

Objective: This work aims to explore the potential targets and underlying therapeutic mechanisms of celastrol in autoimmune hepatitis (AIH) through network pharmacology and experiments on Laboratory Animals. Methods: A drug-target interaction network was constructed to predict the possible targets of celastrol and their potential relationship with the drug; docking studies were also performed for validation. This study used both acute and chronic rodent models of autoimmune hepatitis. Gross appearance of liver and spleen were obtained from murine models, hematoxylin-eosin staining and Sirius red staining were performed to examine hepatic inflammation and fibrosis respectively. By combining molecular docking and enrichment analysis results, the most prominent signaling pathway was selected and further confirmed by Western blot in AIH models administered with celastrol. Results: In total, 82 common targets of celastrol and AIH were obtained from databases, identified by network pharmacology, and adequately enriched. Among them, PIK3R1, SRC, MAPK1, AKT1, and HRAS were selected as the top 5 closely related targets to celastrol. They all performed effectively in molecular docking, with AKT1 and PIK3R1 exhibiting more-prominent binding energy. Subsequently, celastrol administration significantly ameliorated hepatitis and liver fibrosis by reducing AKT1 and PI3K phosphorylation in both acute liver injury and chronic models of autoimmune hepatitis. Conclusion: In summary, celastrol significantly attenuates autoimmune hepatitis by suppressing the PI3K/AKT signaling pathway, confirmed by validated animal models. These findings may help identify the mechanism involved in the anti-inflammatory action of celastrol in autoimmune hepatitis and provide ideas for future comprehensive studies.

Celastrol Attenuates Learning and Memory Deficits in an Alzheimer's Disease Rat Model.

Alzheimer's disease (AD) is a chronic progressive neurodegenerative disorder that is associated with learning, memory, and cognitive deficits. Neuroinflammation and synapse loss are involved in the pathology of AD. Diverse measures have been applied to treat AD, but currently, there is no effective treatment. Celastrol (CEL) is a pentacyclic triterpene isolated from Tripterygium wilfordii Hook F that has been shown to enhance cell viability and inhibit amyloid-β production induced by lipopolysaccharides in vitro. In the present study, the protective effect of CEL on Aβ25-35-induced rat model of AD was assessed. Our results showed that CEL administration at a dose of 2 mg/kg/day improved spatial memory in the Morris water maze. Further biochemical analysis showed that CEL treatment of intrahippocampal Aβ25-35-microinjected rats attenuated hippocampal NF-κB activity; inhibited proinflammatory markers, namely, IL-1β, IL-6, and TNF-α; and upregulated anti-inflammatory factors, such as IL-4 and IL-10. Furthermore, CEL upregulated hippocampal neurexin-1β, neuroligin-1, CA1, and PSD95 expression levels, which may improve synaptic function. Simultaneously, CEL also increased glucose metabolism in Aβ25-35-microinjected rats. In conclusion, CEL could exert protective effects against learning and memory decline induced by intrahippocampal Aβ25-35 through anti-inflammation, promote synaptic development, and maintain hippocampal energy metabolism.

Celastrol protects against early brain injury after subarachnoid hemorrhage in rats through alleviating blood-brain barrier disruption and blocking necroptosis.

Background: Subarachnoid hemorrhage (SAH) is a life-threatening disease worldwide, and effective pharmaceutical treatment is still lacking. Celastrol is a plant-derived triterpene which showed neuroprotective potential in several types of brain insults. This study aimed to investigate the effects of celastrol on early brain injury (EBI) after SAH.Methods: A total of sixty-one male Sprague-Dawley rats were used in this study. Rat SAH endovascular perforation model was established to mimic the pathological changes of EBI after SAH. Multiple methods such as 3.0T MRI scanning, immunohistochemistry, western blotting and propidium iodide (PI) labeling were used to explore the therapeutic effects of celastrol on SAH.Results: Celastrol treatment attenuated SAH-caused brain swelling, reduced T2 lesion volume and ventricular volume in MRI scanning, and improved overall neurological score. Albumin leakage and the degradation of tight junction proteins were also ameliorated after celastrol administration. Celastrol protected blood-brain bairrer integrity through inhibiting MMP-9 expression and anti-neuroinflammatory effects. Additionally, necroptosis-related proteins RIP3 and MLKL were down-regulated and PI-positive cells in the basal cortex were less in the celastrol-treated SAH group than that in untreated SAH group.Conclusions: Celastrol exhibits neuroprotective effects on EBI after SAH and deserves to be further investigated as an add-on pharmaceutical therapy.

Detection and quantification of the anti-obesity drug celastrol in murine liver and brain

Celastrol is a natural pentacyclic triterpene extracted from the roots of Tripterygium wilfordi (thunder god vine). Celastrol was reported as a powerful anti-obesity drug with leptin sensitizing properties that decreases food consumption and mediates body weight loss when administered to diet-induced obese mice at 100 μg/kg body weight. The weight lowering properties of celastrol are likely mediated by the CNS, in particular, by the hypothalamus, but the final proof for the accumulation of celastrol in the brain and hypothalamus remains to be established. Here, we aimed to demonstrate that intraperitoneal celastrol administration at 100 μg/kg can rapidly reach the brain and, in particular, the hypothalamus of mice. We developed and validated a sensitive liquid chromatography mass spectrometry method for the quantitative determination of celastrol in murine tissues, namely liver, brain and hypothalamus. Chow-fed lean mice were randomly assigned to the vehicle vs. celastrol groups, injected with saline or 100 μg/kg body weight of celastrol, and sacrificed 30 min or 120 min post injection. Celastrol was extracted from homogenized tissue using ethyl acetate as organic solvent, and quantified using a matrix-matched calibration curve with glycyrrhetinic acid as internal standard. Liver celastrol concentrations were 32.60 ± 8.21 pg/mg and 40.52 ± 15.6 pg/mg, 30 and 120 min after injection, respectively. We found 4.70 ± 0.31 pg/mg celastrol after 30 min, and 16.22 ± 3.33 pg/mg after 120 min in whole brain lysates, and detectable amounts in the hypothalamus. These results corroborate the validity of our methodology, demonstrate the accumulation of celastrol in the brain of mice injected intraperitoneally with a dose of 100 μg/kg, and confirm the CNS as possible site of action for the weight lowering properties of celastrol.

Celastrol Attenuates Angiotensin II-Induced Cardiac Remodeling by Targeting STAT3.

Excessive Ang II (angiotensin II) levels lead to a profibrotic and hypertrophic milieu that produces deleterious remodeling and dysfunction in hypertension-associated heart failure. Agents that disrupt Ang II-induced cardiac dysfunction may have clinical utility in the treatment of hypertension-associated heart failure. We have examined the potential effect of celastrol-a bioactive compound derived from the Celastraceae family-on Ang II-induced cardiac dysfunction. In rat primary cardiomyocytes and H9C2 (rat cardiomyocyte-like H9C2) cells, celastrol attenuates Ang II-induced cellular hypertrophy and fibrotic responses. Proteome microarrays, surface plasmon resonance, competitive binding assays, and molecular simulation were used to identify the molecular target of celastrol. Our data showed that celastrol directly binds to and inhibits STAT (signal transducer and activator of transcription)-3 phosphorylation and nuclear translocation. Functional tests demonstrated that the protection of celastrol is afforded through targeting STAT3. Overexpression of STAT3 dampens the effect of celastrol by partially rescuing STAT3 activity. Finally, we investigated the in vivo effect of celastrol treatment in mice challenged with Ang II and in the transverse aortic constriction model. We show that celastrol administration protected heart function in Ang II-challenged and transverse aortic constriction-challenged mice by inhibiting cardiac fibrosis and hypertrophy. Our studies show that celastrol inhibits Ang II-induced cardiac dysfunction by inhibiting STAT3 activity.

Early Celastrol Administration Prevents Ketamine-Induced Psychotic-Like Behavioral Dysfunctions, Oxidative Stress and IL-10 Reduction in The Cerebellum of Adult Mice.

Administration of subanesthetic doses of ketamine during brain maturation represents a tool to mimic an early insult to the central nervous system (CNS). The cerebellum is a key player in psychosis pathogenesis, to which oxidative stress also contributes. Here, we investigated the impact of early celastrol administration on behavioral dysfunctions in adult mice that had received ketamine (30 mg/kg i.p.) at postnatal days (PNDs) 7, 9, and 11. Cerebellar levels of 8-hydroxydeoxyguanosine (8-OHdG), NADPH oxidase (NOX) 1 and NOX2, as well as of the calcium-binding protein parvalbumin (PV), were also assessed. Furthermore, celastrol effects on ketamine-induced alterations of proinflammatory (TNF-α, IL-6 and IL-1β) and anti-inflammatory (IL-10) cytokines in this brain region were evaluated. Early celastrol administration prevented ketamine-induced discrimination index decrease at adulthood. The same was found for locomotor activity elevations and increased close following and allogrooming, whereas no beneficial effects on sniffing impairment were detected. Ketamine increased 8-OHdG in the cerebellum of adult mice, which was also prevented by early celastrol injection. Cerebellar NOX1 levels were enhanced at adulthood following postnatal ketamine exposure. Celastrol per se induced NOX1 decrease in the cerebellum. This effect was more significant in animals that were early administered with ketamine. NOX2 levels did not change. Ketamine administration did not affect PV amount in the cerebellum. TNF-α levels were enhanced in ketamine-treated animals; however, this was not prevented by early celastrol administration. While no changes were observed for IL-6 and IL-1β levels, ketamine determined a reduction of cerebellar IL-10 expression, which was prevented by early celastrol treatment. Our results suggest that NOX inhibition during brain maturation prevents the development of psychotic-like behavioral dysfunctions, as well as the increased cerebellar oxidative stress and the reduction of IL-10 in the same brain region following ketamine exposure in postnatal life. This opens novel neuroprotective opportunities against early detrimental insults occurring during brain development.

Celastrol Reduces Obesity in MC4R Deficiency and Stimulates Sympathetic Nerve Activity Affecting Metabolic and Cardiovascular Functions.

Leptin resistance is a hallmark of obesity with unclear etiology. Celastrol, a compound found in the roots of the Tripterygium wilfordii and known to reduce endoplasmic reticulum (ER) stress, has recently emerged as a promising candidate to treat obesity by improving leptin sensitivity. However, the underlying neural mechanisms by which celastrol reduces obesity remain unclear. Using three different mouse models of obesity-diet-induced obesity (DIO), leptin receptor (LepR)-null, and melanocortin 4 receptor (MC4R)-null mice-in this study, we show that systemic celastrol administration substantially reduces food intake and body weight in MC4R-null comparable to DIO, proving the MC4R-independent antiobesity effect of celastrol. Body weight reduction was due to decreases in both fat and lean mass, and modest but significant body weight reduction was also observed in nonobese wild-type and LepR-null mice. Unexpectedly, celastrol upregulated proinflammatory cytokines without affecting genes involved in ER stress. Importantly, celastrol steadily increased sympathetic nerve activity to the brown fat and kidney with concordant increases of resting metabolic rate and arterial pressure. Our results suggest a previously unappreciated mechanism of action of celastrol in the regulation of energy homeostasis and highlight the need for careful consideration of its development as a safe antiobesity medication.

The leptin sensitizer celastrol reduces age-associated obesity and modulates behavioral rhythms.

The prevalence of obesity increases with age in humans and in rodents. Age‐related obesity is characterized by leptin resistance and associated with heightened risk of metabolic disorders. However, the effect of leptin resistance per se has been difficult to disentangle from other effects of aging. Here we demonstrate that celastrol, a natural phytochemical that was previously shown to act as a leptin sensitizer, induces weight loss in aged animals, but not in young controls. Celastrol reduces food intake and lowers fasting glucose without affecting energy expenditure. Unexpectedly, administration of celastrol just before the dark period disrupted circadian rhythms of sleep and activity. This regimen was also associated with loss of lean mass an outcome that would not be desirable in elderly patients. Adjusting the timing of celastrol administration by 12 hr, to the beginning of the light period, avoided interference with circadian rhythms while retaining the reductions in body weight and adiposity. Thus, targeting leptin signaling is an effective strategy to ameliorate age‐associated weight gain, and can profoundly impact circadian rhythms.

Celastrol Attenuates Intrahepatic Cholestasis of Pregnancy by Inhibiting Matrix Metalloproteinases-2 and 9

Introduction and aim. Matrix metalloproteinase (MMP)-2 and MMP-9 are reported to participate in several pregnancy-related diseases, including intrahepatic cholestasis of pregnancy (ICP), which is a severe liver disorder in pregnant women. Meanwhile, ample evidences have demonstrated that celastrol inhibits the activity and expression of MMPs. The present study aims to examine the effect of celastrol to alleviate symptoms of ICP in rat model.Material and methods. By inducing ICP with 17 - ethinylestradiol in pregnant female rats, we assessed the impact of celastrol administration on symptoms of ICP, such as the rate of bile flow, the level of total bile acids (TBA), and the activities of MMP-2 and -9. Furthermore, the correlations between the levels of MMPs with the examined ICP symptoms were investigated.Results. In rats with ICP, both MMP-2 and -9 exhibited significantly elevated activities, which were inhibited by the administration of celastrol. Furthermore, ICP symptoms such as bile flow rate and total TBA were restored by celastrol. Lastly, there were strong correlations between levels of the two MMPs and TBA.Conclusion. Our findings described for the first time the effects of celastrol to attenuate ICP symptoms through an inhibition of both MMP-2 and -9, providing evidence for a potential role of celastrol as a new drug for the treatment of ICP.

Genetic and Pharmacological Targeting of Heat Shock Protein 70 in the Mouse Amygdala-Kindling Model.

Inflammatory responses involving Toll-like receptor signaling represent a key factor contributing to epileptogenesis. Thus, it is of particular interest to explore the relevance of toll-like receptor ligands and modulators, such as heat shock protein 70 (HSP70). Motivated by recent findings demonstrating an upregulation of HSP70 in a model of epileptogenesis, we analyzed the consequences of genetic and pharmacological targeting of HSP70 expression in a mouse kindling paradigm. Lack of inducible HSP70 resulted in increased prekindling seizure thresholds. However, at threshold stimulation the deficiency-promoted seizure spread, as indicated by an increased seizure severity. Subsequent kindling stimulations elicited more severe seizures in knockout mice, whereas endogenous termination of seizure activity remained unaffected with duration of behavioral and electrographic seizure activity comparable to that of wild-type mice. Interestingly, HSP70 deficiency resulted in enhanced microglia activation in the CA1 region. Next, we assessed a pharmacological targeting approach aiming to promote HSP70 expression. Celastrol treatment had no impact on kindling progression but reduced postkindling seizure thresholds and enhanced microglia activation in CA1 and CA3. In conclusion, the findings from HSP70-knockout mice support a protective role of HSP70 with an effect on microglia activation and spread of seizure activity. Unexpectedly, celastrol administration resulted in detrimental consequences. These findings should be considered as a warning about the general safety of celastrol as a drug candidate. The impact of pathophysiological mechanisms on the quality of celastrol effects requires comprehensive future studies exploring influencing factors. Moreover, alternate strategies to increase HSP70 expression should be further developed and validated.

Celastrol ameliorates cisplatin nephrotoxicity by inhibiting NF-κB and improving mitochondrial function.

BackgroundCelastrol is an active ingredient of Chinese medicine Tripterygium wilfordii which is clinically used to treat the immune diseases. Currently, celastrol is documented as a potent agent for treating cancer and inflammatory disorders. This study was to investigate the effect of celastrol on cisplatin nephrotoxicity and the underlying mechanism.MethodsMale C57BL/6 mice were treated with cisplatin (20 mg/kg) with or without celastrol treatment (1 and 2 mg/kg/day). In vitro, human proximal tubule epithelial cell line (HK−2) and mouse renal tubule epithelial cells (RTECs) were treated with cisplatin (5 μg/mL) with or without celastrol administration. Then renal injury and cell damage were evaluated.FindingsIn vivo, after celastrol treatment, cisplatin-induced kidney injury was significantly ameliorated as shown by the improvement of renal function (BUN, serum creatinine, and cystatin C), kidney morphology (PAS staining) and oxidative stress (MDA) and the suppression of renal tubular injury markers of KIM-1 and NGAL. Meanwhile, the renal apoptosis and inflammation induced by cisplatin were also strikingly attenuated in celastrol-treated mice. In vitro, celastrol treatment markedly inhibited cisplatin-induced renal tubular cell apoptosis, suppressed NF-κB activation, and improved mitochondrial function evidenced by the restored mtDNA copy number, mitochondrial membrane potential, and OXPHOS activity in cisplatin-treated renal tubular epithelial cells.InterpretationThis work suggested that celastrol could protect against cisplatin-induced acute kidney injury possibly through suppressing NF-κB and improving mitochondrial function.FundThe National Natural Science Foundation of China, National Key Research and Development Program, and Natural Science Foundation of Jiangsu Province.

Celastrol Attenuates Intrahepatic Cholestasis of Pregnancy by Inhibiting Matrix Metalloproteinases-2 and 9

Introduction and aim. Matrix metalloproteinase (MMP)-2 and MMP-9 are reported to participate in several pregnancy-related diseases, including intrahepatic cholestasis of pregnancy (ICP), which is a severe liver disorder in pregnant women. Meanwhile, ample evidences have demonstrated that celastrol inhibits the activity and expression of MMPs. The present study aims to examine the effect of celastrol to alleviate symptoms of ICP in rat model. Material and methods. By inducing ICP with 17 - ethinylestradiol in pregnant female rats, we assessed the impact of celastrol administration on symptoms of ICP, such as the rate of bile flow, the level of total bile acids (TBA), and the activities of MMP-2 and -9. Furthermore, the correlations between the levels of MMPs with the examined ICP symptoms were investigated. Results. In rats with ICP, both MMP-2 and -9 exhibited significantly elevated activities, which were inhibited by the administration of celastrol. Furthermore, ICP symptoms such as bile flow rate and total TBA were restored by celastrol. Lastly, there were strong correlations between levels of the two MMPs and TBA. Conclusion. Our findings described for the first time the effects of celastrol to attenuate ICP symptoms through an inhibition of both MMP-2 and -9, providing evidence for a potential role of celastrol as a new drug for the treatment of ICP.

Celastrol, an active constituent of the TCM plant Tripterygium wilfordii Hook.f., inhibits prostate cancer bone metastasis.

Treatment failure of prostate cancer (PCa) is often due to bone metastasis. Celastrol, an active constituent of Tripterygium wilfordii roots, has shown anti-tumor effects in previous studies in accordance with its indication in traditional Chinese medicine. Using a PC-3 cell model, in vitro assays were performed to evaluate the effects of celastrol on proliferation, migration (wound healing assay), tissues invasion (Transwell-Matrigel penetration assay) and vascular endothelial growth factor (VEGF) secretion (enzyme-linked immunosorbent assay). An intra-tibia injection mouse model was used to assess the effect of celastrol on PCa bone metastasis in vivo. Pretreatment with celastrol significantly reduced proliferation of PC-3 cells in a dose-dependent manner and cell migration was much slower than in controls. Significantly fewer cells penetrated the gel-membrane after celastrol administration and their skeletal invasive ability was significantly reduced in a dose-dependent manner. Correspondingly, a significant, dose-dependent decrease in VEGF secretion was observed. In the in vivo mouse model, pretreatment with celastrol (8 μmol l-1) inhibited the tumorigenicity of PC-3 cells so that almost no bone invasion occurred as compared with control injections. Histological examinations using hematoxylin and eosin staining showed that tibiae injected with celastrol pretreated PC-3 cells retained their natural bone structure. Celastrol may have preventive potential against PCa bone metastasis.