Cepharanthine alleviates liver injury in a rodent model of limb ischemia-reperfusion

The Bis(1,2,3,4-tetrahydroisoquinoline) Alkaloids Cepharanthine and Berbamine Are Ligands of SK Channels

Cepharanthine, a multitarget alkaloid which has recently been shown to be effective against SARS-Cov-2, and berbamine, an alkaloid characterized as a calcium channel blocker, both share key structural elements with known small conductance calcium-activated potassium (SK) channel blockers. These structural similarities led us to evaluate their affinity for SK channels. Therefore, we performed in vitro binding on SK2 and SK3 subtypes and highlighted micromolar to sub-micromolar affinities. Respectively, the Ki values on SK2 and SK3 are 1,318 μM and 1,091 μM for cepharanthine and 0,284 μM and 0,679 μM for berbamine. These newfound affinities correspond to the concentrations at which the alkaloids are found to be active against several pathologies. As SK interactions occur at the same levels as their therapeutic effects, there is a strong incentive to further investigate whether SK channels are involved in their pharmaceutical potency.

Pharmacological Activity of Cepharanthine

Cepharanthine, a natural bisbenzylisoquinoline (BBIQ) alkaloid isolated from the plant Stephania Cephalantha Hayata, is the only bisbenzylisoquinoline alkaloid approved for human use and has been used in the clinic for more than 70 years. Cepharanthine has a variety of medicinal properties, including signaling pathway inhibitory activities, immunomodulatory activities, and antiviral activities. Recently, cepharanthine has been confirmed to greatly inhibit SARS-CoV-2 infection. Therefore, we aimed to describe the pharmacological properties and mechanisms of cepharanthine, mainly including antitumor, anti-inflammatory, anti-pathogen activities, inhibition of bone resorption, treatment of alopecia, treatment of snake bite, and other activities. At the same time, we analyzed and summarized the potential antiviral mechanism of cepharanthine and concluded that one of the most important anti-viral mechanisms of cepharanthine may be the stability of plasma membrane fluidity. Additionally, we explained its safety and bioavailability, which provides evidence for cepharanthine as a potential drug for the treatment of a variety of diseases. Finally, we further discuss the potential new clinical applications of cepharanthine and provide direction for its future development.

Network analysis-based strategy to investigate the protective effect of cepharanthine on rat acute respiratory distress syndrome

Combined with Network Analysis (NA) and in vivo experimental methods, we explored and verified the mechanism of Cepharanthine (CEP) involved in the treatment of acute respiratory distress syndrome (ARDS). Potential targets of CEP were searched using the SwissTargetPrediction database. The pathogenic genes related to ARDS were obtained using the DisGeNET database. A protein-protein interaction network of common target genes of disease-compound was subsequently built and visualised. Functional enrichment analysis was performed through the Enrichr database. Finally, for in vivo experimental verification, we established an oleic acid-induced ARDS rat model, mainly through histological evaluation and the ELISA method to evaluate both the protective effect of CEP on ARDS and its effect on inflammation. A total of 100 genes were found to be CEP targeted genes, while 153 genes were found to be associated with ARDS. The PPI network was used to illustrate the link and purpose of the genes associated with CEP and ARDS, which contained 238 nodes and 2,333 links. GO and KEGG analyses indicated that inflammatory response and its related signalling pathways were closely associated with CEP-mediated ARDS treatment. Thus, a key CEP–gene–pathway-ARDS network was constructed through network analysis, including 152 nodes (5 targets and 6 pathways) and 744 links. The results of in vivo experiments showed that CEP could alleviate histopathological changes and pulmonary edema related to ARDS, in addition to reducing neutrophil infiltration and secretion of inflammatory cytokines, whilst increasing serum contents of ResolvinD1 and ResolvinE1. Thus, these effects enhance the anti-inflammatory responses. Thus, our results show that CEP can treat oleic acid-induced ARDS in rats via ResolvinE1 and ResolvinD1 signalling pathways that promote inflammation resolution, providing a new avenue to explore for the clinical treatment of ARDS.

Bioavailability Enhancement of Cepharanthine via Pulmonary Administration in Rats and Its Therapeutic Potential for Pulmonary Fibrosis Associated with COVID-19 Infection

Cepharanthine (CEP) has excellent anti-SARS-CoV-2 properties, indicating its favorable potential for COVID-19 treatment. However, its application is challenged by its poor dissolubility and oral bioavailability. The present study aimed to improve the bioavailability of CEP by optimizing its solubility and through a pulmonary delivery method, which improved its bioavailability by five times when compared to that through the oral delivery method (68.07% vs. 13.15%). An ultra-performance liquid chromatography tandem-mass spectrometry (UPLC-MS/MS) method for quantification of CEP in rat plasma was developed and validated to support the bioavailability and pharmacokinetic studies. In addition, pulmonary fibrosis was recognized as a sequela of COVID-19 infection, warranting further evaluation of the therapeutic potential of CEP on a rat lung fibrosis model. The antifibrotic effect was assessed by analysis of lung index and histopathological examination, detection of transforming growth factor (TGF)-β1, interleukin-6 (IL-6), α-smooth muscle actin (α-SMA), and hydroxyproline level in serum or lung tissues. Our data demonstrated that CEP could significantly alleviate bleomycin (BLM)-induced collagen accumulation and inflammation, thereby exerting protective effects against pulmonary fibrosis. Our results provide evidence supporting the hypothesis that pulmonary delivery CEP may be a promising therapy for pulmonary fibrosis associated with COVID-19 infection.

Cepharanthine Attenuates Early Brain Injury after Subarachnoid Hemorrhage in Mice via Inhibiting 15-Lipoxygenase-1-Mediated Microglia and Endothelial Cell Ferroptosis

Background

Ferroptosis is a newly identified form of programmed cell death caused by iron-dependent lipid peroxidation. Our study was designed to determine the expression patterns and role of 15-lipoxygenase-1 (ALOX15) in subarachnoid hemorrhage (SAH) and to investigate whether cepharanthine (CEP) can inhibit ferroptosis by inhibiting ALOX15 in specific cell types.

Methods

A mouse model of SAH was developed by the endovascular perforation method. bEend.3 endothelial cells and BV2 microglial cells as well as RSL3 and hemin were used to simulate SAH in vitro. Mice and cell lines were treated with CEP and a group of specific oxygenase inhibitors to explore the protection effect from ferroptosis. Lipid peroxidation staining with BODIPY 581/591 C11 and transmission electron microscopy were used to identify ferroptosis in vitro and in vivo.

Results

In the present study, the accumulation of lipid peroxide, a defect in the glutathione peroxidase 4 (GPx4)/glutathione (GSH) antioxidant system, highly expressed ALOX15 in microglia and endothelium, and ferroptotic changes in microglial mitochondria confirmed the occurrence of ferroptosis after SAH in vivo. Further, CEP was shown to inhibit ferroptosis and improve neurological function by downregulating the expression of ALOX15. During in vitro experiments, we investigated the important role ALOX15 in RSL3-induced endothelial ferroptosis. In addition, we found that M2-type microglia are more sensitive to RSL3-induced ferroptosis than M1-type microglia and that hemin probably induced ferroptosis in M2-type microglia by increasing ALOX15 levels and decreasing GPx4 levels. The effect of CEP treatment was also demonstrated in vitro.

Conclusions

In summary, to the best of our knowledge, this is the first study demonstrating that ferroptosis occurred in the microglia and endothelium after SAH, and this process was facilitated by increased ALOX15 levels. More importantly, treatment with CEP could inhibit ferroptosis through downregulating the expression of ALOX15.

Cepharanthine Regulates Autophagy via Activating the p38 Signaling Pathway in Lung Adenocarcinoma Cells

BACKGROUND

Cepharanthine (CEP) is an alkaloid extracted from Stephania cepharantha Hayata. This compound has been reported as a promising anti-tumor drug, although its potential molecular mechanism is not fully understood. Here, we studied the anti-tumor effect of CEP on human lung cancer cells and evaluated its molecular mechanism.

METHODS

The A549 cells were treated with CEP, the cell viability was measured by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay, and formation of autophagosome was observed by acridine orange staining under a fluorescence microscope. The cell migration and invasion were determined by wound healing and transwell assay. The protein levels of autophagy-associated molecules, light chain 3 (LC3)、p38、and phospho-p38 in A549 cells, were determined by western blot analysis.

RESULT

The results showed that CEP inhibited cell proliferation, migration and invasion in A549 cells. Moreover, we found that CEP resulted in significant increases in levels of the autophagy marker protein LC3 in A549 cells. The number of intracellular acid dye follicular bright red fluorescence in A549 cells was significantly increased after CEP treatment. At the molecular levels, CEP markedly increased the phosphorylation of p38 in A549 cells. The knockdown of p38 expression by siRNA-p38 impaired the autophagy-regulating effect of CEP. Our results indicated that CEP-regulated autophagy was an anti-tumor effect and not a protective response to CEP.

CONCLUSION

Taken together, these results demonstrated that CEP regulated autophagy by activating the p38 signaling pathway, which could be provided a potential application for preventing lung cancer.

Cepharanthine attenuates cerebral ischemia/reperfusion injury by reducing NLRP3 inflammasome-induced inflammation and oxidative stress via inhibiting 12/15-LOX signaling

Cepharanthine (CEP) is a potential candidate for treatment of cerebral ischemia/reperfusion (I/R) injury, due to its anti-inflammatory and anti-oxidative properties. To investigate the effect of CEP on cerebral I/R injury, we established a mouse model of transient middle cerebral artery occlusion (tMCAO) and a microglia cell model of oxygen and glucose deprivation/reoxygenation (OGD/R). Administration of CEP attenuated neurological deficits, reduced infarct volume and edema, and decreased microglia activation in MCAO mice. Immunofluorescence staining showed an up-regulation in NLR Family Pyrin Domain Containing 3 (NLRP3) immunoreactivity in Iba1-labled microglia together with total Iba1 and NLRP3 expression in the brain following tMCAO, while down-regulated by CEP treatment. In both tMCAO-induced mice and OGD/R-treated BV-2 cells, CEP exhibited dose-dependent inhibition on the expression of NLRP3, ASC and cleaved caspase-1. Importantly, CEP attenuated tMCAO or OGD/R-induced overproduction of M1 microglia-regulated pro-inflammation cytokines IL-1β and IL-18, suggesting that CEP might involve in suppressing microglia polarization to M1 phenotype in vivo and in vitro. Moreover, CEP dose-dependently inhibited tMCAO-induced arachidonate 15 lipoxygenase (ALOX15) together with Iba1-labled microglia. The subsequent ALOX15-mediated oxidative stress was decreased by CEP treatment in vivo and in vitro, as evidenced by reduced ROS generation and MDA level, and increased SOD activity. Taken together, we demonstrate that CEP attenuates cerebral I/R injury probably by inhibiting microglia activation and NLRP3 inflammasome-induced inflammation and reducing oxidative stress via suppressing 12/15-LOX signaling.

How important is the damage to the liver after lower limb ischemia-reperfusion? An experimental study in a rat model

Background

The aim of this study was to compare the effect of lower extremity ischemia reperfusion on the liver and the effect of ischemiareperfusion on the liver itself in a rat model.

Methods

Thirty Sprague-Dawley male rats were randomly divided into three groups including 10 in each group: sham (Group 1), lower limb ischemia-reperfusion (Group 2), and liver ischemia-reperfusion (Group 3). In Group 2, one hour of left lower limb ischemia was performed. In Group 3, one hour of ischemia in the liver was performed, followed by 24 hours of reperfusion. After reperfusion, the liver tissues were removed, and the groups were evaluated biochemically and histologically.

Results

The liver malondialdehyde levels were significantly higher in Groups 2 and 3 than in the sham group (p<0.001). In Group 2, the malondialdehyde levels were significantly higher than in Group 3 (p=0.019). The glutathione levels in the liver were significantly lower in Groups 2 and 3 than in the sham group (p<0.001). However, the glutathione levels were significantly higher in Group 2 than in Group 3 (p=0.005). In the histological evaluation, although the liver damage score was higher in Group 3 than in Group 2 (p=0.015), there was no significant difference between the two groups in TUNEL(+) cell number (p>0.05).

Conclusion

Reperfusion injury in the liver after lower limb ischemiareperfusion is as important as ischemia-reperfusion injury which is specifically induced in the liver. This should be taken into account, particularly in reperfusion surgeries following vascular trauma or in cases of leg tourniquets to stop bleeding after lower limb vascular trauma.

Which Distant Organ is Most Affected by Lower Extremity Ischemia-Reperfusion?

BACKGROUND

It has been experimentally shown that reperfusion injury occurs in many remote organs after ischemia-reperfusion (I/R) of the lower extremity. However, which distant organ is affected more after I/R of the lower extremity has not been investigated. In this study, we investigate which remote organ is predominantly affected after lower extremity I/R.

METHODS

Twenty male Sprague-Dawley rats were randomly divided into 2 groups: sham (group 1) and lower extremity I/R (group 2). In group 2, 1 hr of ischemia of the left lower extremity was followed by 24 hr of reperfusion of the limb. After reperfusion, the lung, liver, kidney, heart, and small intestine tissues were harvested in both groups.

RESULTS

In the I/R group, the malondialdehyde levels were significantly higher in the heart and small intestine tissues than those in other tissues (P < 0.05). In addition, in the I/R group, the glutathione and glutathione peroxidase activities were also higher in the heart tissues than those in other tissues (P < 0.05). However, these results were not significant because the malondialdehyde, glutathione, and glutathione peroxidase levels of the heart tissues in the control group were higher than those of the other tissues. Therefore, no statistically significant difference was found between the tissues in terms of the histological damage score we created and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cell numbers.

CONCLUSIONS

There was no difference in the severity of reperfusion injury between the tissues we examined after lower extremity I/R. This suggests that every distal organ should be carefully monitored after lower extremity I/R.

Cepharanthine: An update of its mode of action, pharmacological properties and medical applications

BACKGROUND

Cepharanthine (CEP) is a drug used in Japan since the 1950s to treat a number of acute and chronic diseases, including treatment of leukopenia, snake bites, xerostomia and alopecia. It is the only approved drug for Human use in the large class of bisbenzylisoquinoline alkaloids. This natural product, mainly isolated from the plant Stephania cephalantha Hayata, exhibits multiple pharmacological properties including anti-oxidative, anti-inflammatory, immuno-regulatory, anti-cancer, anti-viral and anti-parasitic properties.

PURPOSE

The mechanism of action of CEP is multifactorial. The drug exerts membrane effects (modulation of efflux pumps, membrane rigidification) as well as different intracellular and nuclear effects. CEP interferes with several metabolic axes, primarily with the AMP-activated protein kinase (AMPK) and NFκB signaling pathways. In particular, the anti-inflammatory effects of CEP rely on AMPK activation and NFκB inhibition.

CONCLUSION

In this review, the historical discovery and development of CEP are retraced, and the key mediators involved in its mode of action are presented. The past, present, and future of CEP are recapitulated. This review also suggests new opportunities to extend the clinical applications of this well-tolerated old Japanese drug.

The influence of alkaloids on oxidative stress and related signaling pathways

Alkaloids have always attracted scientific interest due to either their positive or negative effects on human beings. This review aims to summarize their antioxidant effects by both classical in vitro scavenging assay and at the cellular level. Since most in vitro studies used the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, the results from those studies are summed up in the first part of the article. In the second part, available data on the effect of alkaloids on NADPH-oxidase, the key enzyme for reactive oxygen species production, at the cellular level, are summarized. More than 130 alkaloids were tested by DPPH assay. However, due to methodological differences, a direct comparison is hardly possible. It can be at least concluded that some of them were either similar to or even more active than standard antioxidants and the number of aromatic hydroxyl groups seems to be the major determinant for the activity. The data on inhibition of NADPH-oxidase activity by alkaloids demonstrated that there is little relationship to the DPPH assay. The mechanism seems to be based on inhibition of synthesis, activation or translocation of NADPH-oxidase subunits. In some alkaloids, activation of the nuclear factor Nrf2 pathway was documented to be the grounds for inhibition of NADPH-oxidase. Interestingly, many alkaloids can behave both as anti-oxidants and pro-oxidants depending on conditions and pro-oxidation might be the reason for activation of Nrf2. Available data on other "antioxidant" transcription factors FOXOs and PPARs are also mentioned.

Effects of hyperbaric therapy on liver morphofunctional of rabbits (Oryctolagus cuniculus) after hind limb ischemia-reperfusion injury

AIM

The objective of this research was to study and to prove the effectiveness of hyperbaric oxygen therapy (HBOT) starting time on liver morphofunctional changes after ischemia-reperfusion in the hind limb of rabbits.

MATERIALS AND METHODS

This research used a complete randomized design with 4 groups and 6 repetitions on each. After 6 h artery femoral is ligation, reperfusion was performed for 100 min (G1), HBOT for 90 min after 10 min reperfusion (G2), 10 min reperfusion (G3), and HBOT 90 min after 60 min reperfusion (G4). Then, all of the rabbits were sacrificed. The liver and blood were taken for histopathological changes examination as well as for measuring the level of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The statistical test using Kruskal-Wallis and Mann-Whitney showed that the score of degeneration, necrosis, and portal inflammation in groups without HBOT (G1 and G3) were not significantly different, as well as in group with HBOT (G2 and G4) (p>0.05). However, the scores of histopathological changes in G1 and G3 were significantly different from those in G2 and G4 (p<0.05). The levels of AST and ALT in the groups without hyperbaric therapy (G1 and G3) were not significantly different from those in the groups treated with hyperbaric therapy (G2 and G4) (p>0.05).

RESULT

Hind limb ischemia injury reperfusion can trigger damage for liver morphology, but not lead to liver dysfunction. Reperfusion can trigger increased activity of neutrophils, while neutrophil infiltration in the organ will lead to dysfunction. HBOT can inhibit the activity of neutrophils and the dysfunction of organs caused by ischemic reperfusion.

CONCLUSION

HBOT for 90 min, both 10 and 60 min after the reperfusion, can protect hepatocytes from damage.

Method of Direct Segmental Intra-hepatic Delivery Using a Rat Liver Hilar Clamp Model

Major hepatic surgery with inflow occlusion, and liver transplantation, necessitate a period of warm ischemia, and a period of reperfusion leading to ischemia/reperfusion (I/R) injury with myriad negative consequences. Potential I/R injury in marginal organs destined for liver transplantation contributes to the current donor shortage secondary to a decreased organ utilization rate. A significant need exists to explore hepatic I/R injury in order to mediate its impact on graft function in transplantation. Rat liver hilar clamp models are used to investigate the impact of different molecules on hepatic I/R injury. Depending on the model, these molecules have been delivered using inhalation, epidural infusion, intraperitoneal injection, intravenous administration or injection into the peripheral superior mesenteric vein. A rat liver hilar clamp model has been developed for use in studying the impact of pharmacologic molecules in ameliorating I/R injury. The described model for rat liver hilar clamp includes direct cannulation of the portal supply to the ischemic hepatic segment via a side branch of the portal vein, allowing for direct segmental hepatic delivery. Our approach is to induce ischemia in the left lateral and median lobes for 60 min, during which time the substance under study is infused. In this case, pegylated-superoxide dismutase (PEG-SOD), a free radical scavenger, is infused directly into the ischemic segment. This series of experiments demonstrates that infusion of PEG-SOD is protective against hepatic I/R injury. Advantages of this approach include direct injection of the molecule into the ischemic segment with consequent decrease in volume of distribution and reduction in systemic side effects.