Biliverdin protects against cisplatin-induced apoptosis of renal tubular epithelial cells

Toxicity and Metabolomic Dysfunction Invoked by Febrifugin, a Harmful Component of Edible Nut of Swietenia macrophylla

Swietenia macrophylla fruit is a valuable and historically significant medicinal plant with anti-hypertension and anti-diabetes. We identified a toxic component, Febrifugin, from the edible part of the nut following zebrafish toxicity-guided isolation. Febrifugin is a mexicanolide-type limonoid compound. The toxic factor induced acute toxicity in zebrafish, including yolk sac edema and pericardial edema, reduced body length, decreased melanin deposition, and presented acute skeletal developmental issues. Further exploration of the acute toxicity mechanism through metabolomics revealed that Febrifugin caused significant changes in 13 metabolites in zebrafish larvae, which are involved in the pentose phosphate, tricarboxylic acid (TCA) cycle, and amino acid biosynthesis. The bioassay of oxidative stress capacity and qRT-PCR measurement showed that the compound significantly affected the h6pd gene in the pentose phosphate pathway and the mRNA expression of cs, idh3a, fh, and shda genes in the TCA cycle, leading to reactive oxygen species (ROS) accumulation and a notable decrease in glutathione (GSH) activity in zebrafish. These findings provide a basis for the rational use of S. macrophylla as a medicinal plant and raise awareness of the safety of medicinal plants.

Endogenous stimuli-responsive drug delivery nanoplatforms for kidney disease therapy

Kidney disease is one of the most life-threatening health problems, affecting millions of people in the world. Commonly used steroids and immunosuppressants often fall exceptionally short of outcomes with inescapable systemic toxicity. With the booming research in nanobiotechnology, stimuli-responsive nanoplatform has come an appealing therapeutic strategy for kidney disease. Endogenous stimuli-responsive materials have shown profuse promise owing to their enhanced spatiotemporal control and precise to the location of the lesion. This review focuses on recent advances stimuli-responsive drug delivery nano-architectonics for kidney disease. First, a brief introduction of pathogenesis of kidney disease and pathological microenvironment were provided. Then, various endogenous stimulus involved in drug delivery nanoplatforms including pH, ROS, enzymes, and glucose were categorized based on the pathological mechanisms of kidney disease. Next, we separately summarized literature examples of endogenous stimuli-responsive nanomaterials, and outlined the design strategies and response mechanisms. Finally, the paper was concluded by discussing remaining challenges and future perspectives of endogenous stimuli-responsive drug delivery nanoplatform for expediting the speed of development and clinical applications.

Biliverdin as a disease-modifying agent: An integrated viewpoint

Biliverdin is one of the three by-products of heme oxygenase (HO) activity, the others being ferrous iron and carbon monoxide. Under physiological conditions, once formed in the cell, BV is reduced to bilirubin (BR) by the biliverdin reductase (BVR). However, if BVR is inhibited by either genetic variants, as occurs in the Inuit ethnicity, or dioxin intoxication, BV accumulates in cells giving rise to a clinical syndrome known as green jaundice. Preclinical studies have demonstrated that BV not only has a direct antioxidant effect by scavenging free radicals, but also targets many signal transduction pathways, such as BVR, soluble guanylyl cyclase, and the aryl hydrocarbon receptor. Through these direct and indirect mechanisms, BV has shown beneficial roles in ischemia/reperfusion-related diseases, inflammatory diseases, graft-versus-host disease, viral infections and cancer. Unfortunately, no clinical data are available to confirm these potential therapeutic effects and the kinetics of exogenous BV in humans is unknown. These limitations have so far excluded the possibility of transforming BV from a mere by-product of heme degradation into a disease-modifying agent. A closer collaboration between basic and clinical researchers would be advantageous to overcome these issues and promote translational research on BV in free radical-induced diseases.

Biliverdin modulates the Nrf2/A20/eEF1A2 axis to alleviate cerebral ischemia-reperfusion injury by inhibiting pyroptosis

This study aimed to examine whether Biliverdin, which is a common metabolite of haem, can alleviate cerebral ischemia reperfusion injury (CIRI) by inhibiting pyroptosis. Here, CIRI was induced by middle cerebral artery occlusion-reperfusion (MCAO/R) in C57BL/6 J mice and modelled by oxygen and glucose deprivation/reoxygenation (OGD/R) in HT22 cells, it was treated with or without Biliverdin. The spatiotemporal expression of GSDMD-N and infarction volumes were assessed by immunofluorescence staining and triphenyltetrazolium chloride (TTC), respectively. The NLRP3/Caspase-1/GSDMD pathway, which is central to the pyroptosis process, as well as the expression of Nrf2, A20, and eEF1A2 were determined by Western-blots. Nrf2, A20, and eEF1A2 interactions were verified using dual-luciferase reporter assays, chromatin immunoprecipitation, or co-immunoprecipitation. Additionally, the role of Nrf2/A20/eEF1A2 axis in modulating the neuroprotective properties of Biliverdin was investigated using A20 or eEF1A2 gene interference (overexpression and/or silencing). 40 mg/kg of Biliverdin could significantly alleviate CIRI both in vivo and in vitro, promoted the activation of Nrf2, elevated A20 expression, but decreased eEF1A2 expression. Nrf2 can bind to the promoter of A20, thereby transcriptionally regulating the expression of A20. A20 can furthermore interacted with eEF1A2 through its ZnF4 domain to ubiquitinate and degrade it, leading to the downregulation of eEF1A2. Our studies have also demonstrated that either the knock-down of A20 or over-expression of eEF1A2 blunted the protective effect of Biliverdin. Rescue experiments further confirmed that Biliverdin could regulate the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. In summary, our study demonstrates that Biliverdin ameliorates CIRI by inhibiting the NF-κB pathway via the Nrf2/A20/eEF1A2 axis. Our findings can help identify novel therapeutic targets for the treatment of CIRI.

Physiologically Relevant Levels of Biliverdin Do Not Significantly Oppose Oxidative Damage in Plasma In Vitro

AbstractAntioxidants have important physiological roles in limiting the amount of oxidative damage that an organism experiences. One putative antioxidant is biliverdin, a pigment that is most commonly associated with the blue or green colors of avian eggshells. However, despite claims that biliverdin functions as an antioxidant, neither the typical physiological concentrations of biliverdin in most species nor the ability of biliverdin to oppose oxidative damage at these concentrations has been examined. Therefore, we quantified biliverdin in the plasma of six bird species and found that they circulated levels of biliverdin between 0.02 and 0.5 μM. We then used a pool of plasma from northern bobwhite quail (Colinus virginianus) and spiked it with one of seven different concentrations of biliverdin, creating plasma-based solutions ranging from 0.09 to 231 μM biliverdin. We then compared each solution's ability to oppose oxidative damage in response to hydrogen peroxide relative to a control addition of water. We found that hydrogen peroxide consistently induced moderate amounts of oxidative damage (quantified as reactive oxygen metabolites) but that no concentration of biliverdin ameliorated this damage. However, biliverdin and hydrogen peroxide interacted, as the amount of biliverdin in hydrogen peroxide-treated samples was reduced to approximately zero, unless the initial concentration was over 100 μM biliverdin. These preliminary findings based on in vitro work indicate that while biliverdin may have important links to metabolism and immune function, at physiologically relevant concentrations it does not detectably oppose hydrogen peroxide-induced oxidative damage in plasma.

Induction of cell apoptosis by biliverdin reductase inhibitor in MCF-7 and MDA-MB-468 breast cancer cell lines: Experimental and in silico studies

Biliverdin reductase, biliverdin and bilirubin are known as important components of cellular signaling pathways that play major roles in cell proliferation and apoptosis, although their physiological relevance is still under evaluation. This study was designed to investigate the expression and activity of BVR-A and its apoptotic effect in the breast cancer cell lines, MCF-7 and MDA-MB-468. The expression of BVR-A was examined by real-time PCR and western blot analysis. Bilirubin concentration was measured by HPLC and molecular docking was performed to identify an appropriate inhibitor for BVR-A. To detect cell apoptosis, annexin V-PI staining, caspase-3, -8, and -9 activities were evaluated. Cell viability was reduced by biliverdin, in a dose-dependent manner, and an intrinsic apoptotic response occurred which was evidenced by caspase-3 and -9 activities. The intra- and extracellular concentrations of bilirubin were higher in MCF-7 cells than those of MDA-MB-468 cells. The expression of BVR-A, at mRNA and protein levels, in MCF-7 was also higher than that of MDA-MB-468 cells. Treatment of both cell lines with biliverdin plus DTNB, a BVR-A inhibitor, increased the cell death significantly when compared with biliverdin alone. Using annexin V-PI staining and assessment of caspase-3 activity, it was confirmed that biliverdin together with DTNB increases apoptosis in breast cancer cells. In conclusion, biliverdin has an important role in cell apoptosis and inhibition of biliverdin reductase increases the apoptotic effect of biliverdin.

Rosamultin from Potentilla anserine L. exhibits nephroprotection and antioxidant activity by regulating the reactive oxygen species/C/EBP homologous protein signaling pathway

Rosamultin, a major bioactive constituent from Potentilla anserine L., has antioxidative and hepatoprotective activities. However, its protective effects on cisplatin-induced acute renal injury and the underlying mechanisms remain elusive. In this work, rosamultin could enhance the viability of HEK293 cells treated by cisplatin. In vivo experiment showed that rosamultin effectively decreased kidney index, reduced blood urea nitrogen level, decreased urinary protein excretion, and ameliorated the histopathological damage and fibrosis of renal tissue induced by cisplatin. Besides, rosamultin showed no obvious toxicity in mice. SILAC-based quantitative proteomic analysis identified 4,461 proteins and eight proteins including C/EBP homologous protein (CHOP) were markedly decreased in cisplatin-treated HEK293 cells when exposed to rosamultin. Biochemical experiments further discovered that rosamultin could inhibit p38 and JNK activation, and downregulate the levels of CHOP and proteins in its upstream PERK-eIF2α-ATF4 signaling pathway stimulated by cisplatin or tunicamycin. At the same time, rosamultin reduced the generation of intracellular ROS induced by cisplatin and enhanced the activities of antioxidant enzymes such as SOD, GSH, and CAT. Moreover, rosamultin markedly suppressed the expression of CHOP, apoptosis-associated proteins, and activation of p38 and JNK in renal tissue. These findings suggest that rosamultin might be a potential protectant against cisplatin-induced nephrotoxicity.

Immunomodulatory Effects of Heme Oxygenase-1 in Kidney Disease

Kidney disease is a general term for heterogeneous damage that affects the function and the structure of the kidneys. The rising incidence of kidney diseases represents a considerable burden on the healthcare system, so the development of new drugs and the identification of novel therapeutic targets are urgently needed. The pathophysiology of kidney diseases is complex and involves multiple processes, including inflammation, autophagy, cell-cycle progression, and oxidative stress. Heme oxygenase-1 (HO-1), an enzyme involved in the process of heme degradation, has attracted widespread attention in recent years due to its cytoprotective properties. As an enzyme with known anti-oxidative functions, HO-1 plays an indispensable role in the regulation of oxidative stress and is involved in the pathogenesis of several kidney diseases. Moreover, current studies have revealed that HO-1 can affect cell proliferation, cell maturation, and other metabolic processes, thereby altering the function of immune cells. Many strategies, such as the administration of HO-1-overexpressing macrophages, use of phytochemicals, and carbon monoxide-based therapies, have been developed to target HO-1 in a variety of nephropathological animal models, indicating that HO-1 is a promising protein for the treatment of kidney diseases. Here, we briefly review the effects of HO-1 induction on specific immune cell populations with the aim of exploring the potential therapeutic roles of HO-1 and designing HO-1-based therapeutic strategies for the treatment of kidney diseases.

Biliverdin Protects Against Cerebral Ischemia/Reperfusion Injury by Regulating the miR-27a-3p/Rgs1 Axis

BACKGROUND

We have previously demonstrated that biliverdin has neuroprotective effects that ameliorate cerebral ischemia/reperfusion (I/R) injury in rats. However, the underlying mechanism is unknown. This study aimed at elucidating on the modulatory role of miR-27a-3p on Rgs1 as a mechanism by which biliverdin affects cerebral I/R injury.

METHODS

Middle cerebral artery occlusion/reperfusion (MCAO/R) was used to establish I/R rat models while oxygen glucose deprivation/reoxygenation (OGD/R) was used to induce hippocampal neurons to establish I/R models in vitro. Infarct volume was assessed by TTC staining. Apoptotic analyses of ischemic cortical neurons and cells were performed by TUNEL staining and flow cytometry, respectively. Cell viability was assessed by the CCK-8 assay while the target of miR-27a-3p was determined by double luciferase reporter assay. Relative expression levels of miR-27a-3p and Rgs1 (in vivo and in vitro) as well as markers of inflammation and apoptosis (in vitro) were detected by RT-qPCR. Then, Elisa and western blot were used to assess protein expression levels of inflammatory and apoptotic markers in vitro.

RESULTS

Biliverdin suppressed inflammation and apoptosis in hippocampal neurons upon OGD/R, and reduced cerebral infarction volume as well as apoptosis in the MCAO/R rat model. Furthermore, biliverdin upregulated miR-27a-3p and downregulated hippocampal neuron Rgs1 after OGD/R as well as in rat brain tissues after cerebral I/R. Bioinformatic analysis revealed an miR-27a-3p docking site in the 3'-UTR region of Rgs1. Luciferase reporter assays showed that Rgs1 is an miR-27a-3p target. Moreover, miR-27a-3p upregulation inhibited OGD/R-triggered inflammation and suppressed neuronal apoptosis. Rgs1 knockdown suppressed OGD/R-triggered inflammation and decreased neuronal apoptosis while miR-27a-3p downregulation reversed the protective effect of Rgs1 knockdown. Moreover, miR-27a-3p overexpression and Rgs1 silencing suppressed NF-κB (p65) expression.

CONCLUSION

Biliverdin protects against cerebral I/R injury by regulating the miR-27a-3p/Rgs1 axis, thereby inhibiting inflammation and apoptosis.

Danshen modulates Nrf2-mediated signaling pathway in cisplatin-induced renal injury

Danshen, an efficacious agent for cardiovascular diseases, has been found to play an essential role in kidney injury. In the present study, the effect of Danshen on cisplatin-induced renal dysfunction was investigated in a mouse model. Danshen was administered to mice at a dose of 3 g/kg 4 days before and 3 days after cisplatin treatment. A single intraperitoneal injection of 20 mg/kg cisplatin was used to induce nephrotoxicity. The mice were sacrificed 72 h after cisplatin intoxication. Biochemical parameters including serum creatinine and blood urea nitrogen were analyzed. Histopathological changes of kidney tissues were detected using HE staining. Antioxidant enzymes (GSH-Px and SOD) and peroxidative product (MDA) were detected. Protein expressions of Nrf2 and its target genes including HO-1 and NQO1 were measured by Western blotting. The results showed that pretreatment with Danshen significantly reduced serum creatinine and blood urea nitrogen in the cisplatin-treated mice. Histopathological examination showed that Danshen mitigated the renal damage induced by cisplatin. Moreover, Danshen restored the activities of antioxidant enzymes (GSH-Px and SOD) and normalized the MDA contents in renal tissues. Western blotting revealed that Danshen enhanced the expressions of Nrf2 and its target genes in cisplatin-exposed mice. It was suggested that Danshen protects against the cisplatin-induced renal impairment in the mice, which is potentially associated with the upregulation of Nrf2-mediated signaling pathway.