Cisplatin Protects against Acute Liver Failure by Inhibiting Nuclear HMGB1 Release. Int J Mol Sci. 2013;14:11224-11237. [PMID: 23712360 DOI: 10.3390/ijms140611224]

Inhibition of the HMGB1/RAGE axis protects against cisplatin-induced ototoxicity via suppression of inflammation and oxidative stress

As an anti-tumor drug widely used in the clinic, cisplatin is limited by its ototoxic side effects associated with various factors, including inflammatory responses. Receptor for Advanced Glycation Endproducts (RAGE) recognizes damage-associated molecular patterns (DAMPs) and promotes stress and inflammation. This study intended to determine the potential behavior of the HMGB1/RAGE axis after cisplatin injury and whether it has a protective effect after inhibiting this pathway. We used FPS-ZM1, a RAGE inhibitor, to modulate the axis of HMGB1/RAGE in neonatal mouse cochlear explants and C57BL/6 mice in vivo. Apoptosis was identified by Annexin V-FITC/PI assay, Cleaved Caspase-3, and TUNEL staining. Reactive oxygen species (ROS) level was assessed by MitoSOX Red and CellROX Green assay. The expression of proteins associated with the HMGB1/RAGE axis and apoptosis was observed by western blotting. The expression of inflammatory cytokines was evaluated by qPCR. The protective effect of HMGB1/RAGE knockdown was also assessed on cisplatin-induced ototoxicity. These results demonstrated that cisplatin could activate the HMGB1/RAGE pathway in cochlear hair cells and release inflammatory factors. Pretreatment with FPS-ZM1 alleviated cisplatin-induced ototoxicity in vivo and in vitro. Knocking down HMGB1 and RAGE achieved specific protective effects. Altogether, inhibiting HMGB1/RAGE axis can reverse the increase of ROS accumulation, the activation of apoptosis, and the production of inflammatory reactions after cisplatin injury. FPS-ZM1 could resist the ototoxicity of cisplatin by suppressing the HMGB1/RAGE signal pathway, and it may be considered the new otoprotective potential strategy for hearing loss.

Limonin ameliorates cisplatin-induced acute liver injury by inhibiting 11β-hydroxysteroid dehydrogenase type 1

BACKGROUND

Acute liver injury (ALI) is a common side effect of cisplatin treatment in the clinic and can lead to liver failure if not treated promptly. Previous studies have revealed that Limonin, a critical bioactive substance in citrus fruits, can protect multiple organs from various medical conditions. However, whether Limonin could ameliorate cisplatin-induced ALI remains unclear.

METHODS

In vivo and in vitro models were induced by cisplatin in the present study. Non-targeted metabolomics was employed to analyze the metabolic changes in the liver after ALI. In addition, molecular docking was utilized to predict the potential targets of Limonin.

RESULTS

Limonin attenuated hepatic histopathological injury by reducing hepatocyte apoptosis, lipid peroxidation, and inflammation in cisplatin-challenged mice. Employing metabolomics, we revealed that Limonin mediated the balance of various disturbed metabolic pathways in the liver after cisplatin-induced ALI. Integrating public data mining, molecular docking studies, and in vitro experiments demonstrated that Limonin suppressed the expression and activity of its direct target, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), in the liver, thus reducing the production of corticosterone (CORT), a key metabolite promoted hepatocyte apoptosis.

CONCLUSIONS

Limonin improves the liver metabolic microenvironment by inhibiting 11β-HSD1 to protect against cisplatin-induced ALI.

Extracellular gp96 is a crucial mediator for driving immune hyperactivation and liver damage

Liver failure leads to the massive necrosis of hepatocytes, releasing large amounts of intracellular components including damage-associated molecular patterns (DAMPs). We found that extracellular gp96 levels in serum were elevated in patients with chronic hepatitis B infection (CHB) and acute-on-chronic liver failure (ACLF). Meanwhile, the gp96 level positively correlated with hepatic necroinflammation. We employed two mouse liver damage and liver failure models induced by lipopolysaccharide (LPS) plus d-galactosamine (d-Galn), and concanavalin A (ConA) to identify the function of extracellular gp96. As a result, the inhibition of extracellular gp96 by a specific peptide efficiently mitigated both LPS/d-Galn- and ConA-induced liver injury and immune hyperactivation, whereas exogenous gp96 aggravated the symptoms of hepatic injury in mice but not in Kupffer cells-ablated mice. The exposure of Kupffer cells to gp96 induced the secretion of pro-inflammatory cytokines. Collectively, our data demonstrate that gp96 released from necrotic hepatocytes aggravates immune hyperactivation and promotes liver damage and possibly the development of liver failure mainly by activating Kupffer cells.

Resveratrol Reduced Liver Damage After Liver Resection in a Rat Model by Upregulating Sirtuin 1 (SIRT1) and Inhibiting the Acetylation of High Mobility Group Box 1 (HMGB1)

Background

Liver failure after resection for liver cancer is associated with increased patient mortality. This study aimed to investigate the mechanism of the protective effects of resveratrol, a natural plant-derived compound, on liver injury in a rat model of partial hepatectomy.

Material/Methods

Adult male Sprague-Dawley (SD) rats (n=60) were divided into the sham group (n=20), the liver resection group (n=20), and the liver resection plus resveratrol-treated group (n=20). Liver resection removed 2/3 of the liver resection; resveratrol was given at a dose of 30 mg/kg/day from one week before surgery until death. Liver injury was assessed by serum liver function tests, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl-transferase (γ-GT) and total bilirubin, histological examination of the rat liver, and liver cell apoptosis using the TUNEL assay. High mobility group box 1 (HMGB1) expression was measured by enzyme-linked immunoassay (ELISA). Sirtuin 1 (SIRT1) and acetylated HMGB1 (Ac-HMGB1) expression were detected by Western blot. Normal human liver cells and HepG2 liver cancer cells were incubated with acetylated HMGB1, and albumin production and ammonia elimination assays were performed.

Results

Resveratrol reduced postoperative liver injury as shown by reduced ALT, AST, γ-GT, and total bilirubin levels, maintained liver structure, and reduced cell apoptosis. Resveratrol treatment reduced the expression and acetylation levels of HMGB1 via the SIRT1 signaling pathway. Resveratrol reversed Ac-HMGB1 induced dysfunction in liver cells cultured in vitro.

Conclusions

Resveratrol reduced liver damage after liver resection in a rat model by upregulating SIRT1 and reducing the acetylation of HMGB1.

Inhibitory effects of lupane‑type triterpenoid saponins from the leaves of Acanthopanax gracilistylus on lipopolysaccharide-induced TNF‑α, IL‑1β and high‑mobility group box 1 release in macrophages

Acanthopanax gracilistylus (AGS) has long been used in traditional Chinese medicine for the treatment of various inflammatory diseases. 3‑O‑β‑D‑glucopyranosyl 3α, 11α‑dihydroxylup‑20(29)‑en‑28‑oic acid, acantrifoside A, acankoreoside D, acankoreoside B and acankoreoside A are major lupane‑type triterpenoid saponins derived from AGS. In the present study, these five saponins were isolated from AGS by chromatography and their anti‑inflammatory activities were investigated in lipopolysaccharide (LPS)‑treated RAW264.7 macrophages. Cell viability was evaluated by MTT assay. Tumor necrosis factor (TNF)‑α, interleukin (IL)‑1β and NF‑κB p65 were measured by ELISA. The gene expression levels of TNF‑α and IL‑1β was detected by reverse‑transcription polymerase chain reaction. And high‑mobility group box 1 (HMGB1) were analyzed by western blotting. The results demonstrated that these five saponins significantly suppressed LPS‑induced expression of TNF‑α and IL‑1β at the mRNA and protein level in RAW264.7 cells. Further analysis revealed that acankoreoside A and acankoreoside B were able to reduce the secretion of HMGB1 and NF‑κB activity induced by LPS in RAW264.7 macrophages. Taken together, these results suggested that the anti‑inflammatory activity of AGS‑derived saponins may be associated with the downregulation of TNF‑α and IL‑1β, and the 'late‑phase' proinflammatory cytokine HMGB1, via negative regulation of the NF‑κB pathway in RAW264.7 cells.

Signalling via the osteopontin and high mobility group box-1 axis drives the fibrogenic response to liver injury

OBJECTIVE

Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression.

DESIGN AND RESULTS

Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl₄-injected Opn^Hep transgenic yet it was less in wild type and almost absent in Opn^-/- mice. Hmgb1 ablation in hepatocytes (Hmgb1^ΔHep) protected mice from CCl₄-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by Opn or Hmgb1 ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I.

CONCLUSIONS

During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs.

Inhibitory effects of 3α-hydroxy-lup-20(29)-en-23, 28-dioic acid on lipopolysaccharide-induced TNF-α, IL-1β, and the high mobility group box 1 release in macrophages

We investigated the anti-inflammatory effects of 3α-hydroxy-lup-20(29)-en-23, 28-dioic acid (HLEDA)-a lupane-type triterpene isolated from leaves of Acanthopanax gracilistylus W. W.Smith (AGS), as well as the underlying molecular mechanisms in lipopolysaccharide (LPS)-induced RAW264.7 cells. Our results demonstrated that HLEDA concentration-dependently reduced the production of nitric oxide (NO), significantly suppressed LPS-induced expression of TNF-α and IL-1β at the mRNA and protein levels in RAW264.7 cells. Further analysis revealed that HLEDA could reduce the secretion of High Mobility Group Box 1 (HMGB1). Additionally, the results showed that HLEDA efficiently decreased nuclear factor-kappaB (NF-κB) activation by inhibiting the degradation and phosphorylation of IκBα. These results suggest that HLEDA exerts anti-inflammatory properties in LPS-induced macrophages, possibly through inhibition of the NF-κB signaling pathway, which mediates the expression of pro-inflammatory cytokines. These results warrant further studies that would concern candidate therapy for diseases, such as fulminant hepatitis and rheumatology of triterpenoids in AGS.

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1's multiple functions.

Turning a water and oil insoluble cisplatin derivative into a nanoparticle formulation for cancer therapy

The formulation of water insoluble organic compounds into nanoparticles has become a widely established method for enhancing the delivery and efficacy of cancer therapeutics. Therefore, a comparable approach when applied to water insoluble inorganic compounds should also promote similar advantages. Herein, we have successfully formulated insoluble iodinated cisplatin (CDDP-I) into an LPI NPs (lipid-coated iodinated CDDP nanoparticles). Two separate microemulsions were combined, each containing a precursor for the synthesis of CDDP-I. The resulting CDDP-I precipitate was then coated with an anionic lipid and dispersed in water with the help of an additional lipid. This method allows us to effectively encapsulate CDDP-I and was able to achieve a considerable drug loading of 82 wt%. Administered LPI NPs demonstrated high level accumulation in tumor tissues and exhibited an anti-cancer activity comparable to free CDDP in two melanoma xenograft models without inducing nephrotoxicity. The benefits offered through this delivery formulation are not unique to CDDP-I, as this versatile platform may be extended to the formulation of other inorganic compounds that are both water and oil insoluble into nanoparticles for superior anti-cancer efficacy.

Shikonin inhibits the lipopolysaccharide-induced release of HMGB1 in RAW264.7 cells via IFN and NF-κB signaling pathways

To study the anti-inflammation effect of Shikonin (Shik) and its mechanism, murine macrophage-like RAW264.7 cells (RAW264.7 cells) were divided into control group, LPS group (0.125, 0.25 and 0.5μg/ml), LPS (0.125, 0.25 and 0.5μg/ml) plus Shik (0.5, 1 and 2μM) group, and Shik (2μM) group. After exposure for 24h, the levels of Interleukin-6 (IL-6), nitric oxide (NO) and Tumor Necrosis Factor-α (TNF-α) in supernatant were measured with ELISA, the expression of high mobility group box 1(HMGB1) in supernatant and cytoplasm was assayed using qRT-PCR, western blot and immunofluorescence assays, the expression of IFN-β in cellular and supernatant was assayed by qRT-PCR and ELISA, and the ratio of nuclear to cytoplasm for NF-κB protein expression was assayed using western blot. The results of our investigation demonstrated that Shik could reduce significantly the levels of IL-6, NO and TNF-α in RAW264.7 cells exposed to LPS (P<0.05 or P<0.01). The expression of HMGB1, IFN-β and the ratio of nuclear to cytoplasm for NF-κB protein expression in LPS plus Shik group declined significantly as compared with LPS group (P<0.05 or P<0.01). The inhibitors of IFN-β signaling molecule JAK and NF-κB could attenuate significantly the expression of HMGB1 in supernatant. It was found in the present study that Shik could have the anti-inflammatory effects in RAW264.7 cells exposed to LPS, and one of the mechanisms may be the down-regulation of HMGB expression, which was associated with the IFN-β and NF-κB signaling pathways.

Carbamazepine protects the liver against ischemia/reperfusion injury in mice

AIM: To explore the effects of carbamazepine (CBZ) on hepatic ischemia/reperfusion (I/R) injury in mice.

METHODS: Hepatic ischemia in male Balb/c mice was induced by occluding the portal triad for 1 h, and reperfusion was initiated by removing a microvascular clamp. Mice were randomly assigned to three groups (n = 6 for each group): I/R group as control, CBZ treatment group, and CBZ plus chloroquine (CQ) group. Serum ALT/AST levels at different time points were measured using biochemical methods. Hepatic morphological changes at 6 h after I/R were assessed by HE staining, and hepatocyte high mobility group box 1 (HMGB1) cytoplasmic translocation was detected by immunohistochemistry. Expression of Caspase3, Atg7, Beclin-1 and light chain 3 Ⅱ (LC3Ⅱ) in liver tissue was analyzed by Western blot.

RESULTS: CBZ blocked the depletion of Atg7 and Beclin-1 and LC3II expression after reperfusion. CBZ treatment decreased ALT/AST levels significantly 2, 6 and 12 h after I/R compared with the I/R group (all P < 0.01). Expression of Caspase3 in liver tissue and hepatocyte HMGB1 cytoplasmic translocation at 6 h after I/R were also decreased significantly in the CBZ group (both P < 0.01). CQ antagonized the effect of CBZ in decreasing ALT/AST levels, Caspase3 expression and hepatocyte HMGB1 cytoplasmic translocation.

CONCLUSION: CBZ protects the liver against I/R injury in mice.

Lipid-coated Cisplatin nanoparticles induce neighboring effect and exhibit enhanced anticancer efficacy

Encapsulation of cisplatin (CDDP) into nanoparticles (NPs) with high drug loading and encapsulation efficiency has been difficult due to the poor solubility of CDDP. However, this barrier has been overcome with a reverse microemulsion method appropriating CDDP's poor solubility to our advantage promoting the synthesis of a pure cisplatin nanoparticle with a high drug loading capacity (approximately 80.8 wt %). Actively targeted CDDP NPs exhibited significant accumulation in human A375M melanoma tumor cells in vivo. In addition, CDDP NPs achieved potent antitumor efficacy through the neighboring effect at a dose of 1 mg/kg when injected weekly via iv without inducing nephrotoxicity. The neighboring effect regards an observation made in vivo when the tumor cells that took up CDDP NPs released active drug following apoptosis. Via diffusion, surrounding cells that were previously unaffected showed intake of the released drug and their apoptosis soon followed. This observation was also made in vitro when A375M melanoma tumor cells incubated with CDDP NPs exhibited release of active drug and induced apoptosis on untreated neighboring cells. However, the neighboring effect was unique to rapidly proliferating tumor cells. Liver functional parameters and H&E staining of liver tissue in vivo failed to detect any difference between CDDP NP treated and control groups in terms of tissue health. By simultaneously promoting an increase in cytotoxicity and a lesser degree of side effects over free CDDP, CDDP NPs show great therapeutic potential with lower doses of drug while enhancing anticancer effectiveness.