Xanthohumol attenuates cisplatin-induced nephrotoxicity through inhibiting NF-κB and activating Nrf2 signaling pathways

Amino acid sequences characterization and anti-inflammatory potency evaluation of Portulaca oleracea L. oligopeptides in macrophages

The Portulaca oleracea L. oligopeptides are seldom explored because they are often present in a complex matrix. In the current study, eleven novel Portulaca oleracea L. oligopeptides (POPs) were isolated and their mino acid sequence identified. Further, the anti-inflammatory potency was explored in lipopolysaccharide (LPS)-induced RAW264.7 cells. Results showed that POP-1∼[EHGEYE] possessed excellent anti-inflammatory potency by attenuating the pro-inflammatory cytokine expression (TNF-α, NO, IL-1β); inhibiting iNOS and COX-2 expressions and regulating the MAPK, PI3K/Akt and NF-κB signaling pathways. This may be an important molecular mechanism of POPs in anti-inflammatory damage.

POP-1 performed excellent anti-inflammatory potency by attenuating the pro-inflammatory cytokine expression (TNF-α, NO, IL-1β); inhibiting iNOS and COX-2 expressions and regulating the MAPK, PI3K/Akt and NF-κB signaling pathways.

Cordyceps cicadae Mycelia Ameliorate Cisplatin-Induced Acute Kidney Injury by Suppressing the TLR4/NF-κB/MAPK and Activating the HO-1/Nrf2 and Sirt-1/AMPK Pathways in Mice

Acute kidney injury (AKI) is a common clinical problem, characterized by a sudden loss of renal function, a high risk of death, and the eventual development of renal fibrosis and renal failure. Cordyceps cicadae is a traditional Chinese medicine with the potential function of kidney protection. We analyze two sputum extracts, a water extract (WCC), and an ethanol extract (ECC), to assess the potential of treating AKI in an animal model of kidney injury induced by cisplatin. A nephrotoxic mouse model was first established by intraperitoneal injection of cisplatin. Subsequently, WCC and ECC were orally administered in these mice. The results show that WCC and ECC significantly alleviated cisplatin-induced AKI renal histological changes, serum creatinine (CRE) and blood urea nitrogen (BUN) production, and the levels of NO, TNF-α, IL-1β, and IL-6. The levels of malondialdehyde (MDA) and glutathione (GSH) were suppressed by administration of WCC and ECC. However, WCC treatment prevented these changes significantly better than ECC treatment. In addition, Western blot data showed that WCC attenuated the cisplatin-induced protein expression of cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS), as well as inhibiting nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation in the kidney tissues. Furthermore, WCC greatly inhibited the expression of Toll-like receptor 4 (TLR4) and cisplatin-induced NF-κB activation, as well as dramatically increasing the production of antioxidative enzymes (i.e., superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1)), silent information regulator T1 (Sirt1), and p-AMP-activated protein kinase (AMPK) in the kidney tissues. In addition, we found that WCC increased the expression levels of the autophagy-related proteins LC3B and Beclin-1; proapoptotic proteins, including cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) 1; and organic anion transporters 1 (OAT1) and 3 (OAT3) in the kidney tissues. Finally, WCC, ECC, and two bioactive compounds-adenosine and N6-(2-hydroxyethyl) adenosine (HEA)-inhibited the production of nitrite oxide (NO) and intracellular reactive oxygen species (ROS) triggered by lipopolysaccharide- (LPS-) stimulated RAW264.7 macrophages in vitro. Collectively, WCC could provide a potential therapeutic candidate for the prevention of cisplatin-induced kidney injury through the inhibition of oxidative stress and inflammation.

Benzbromarone mitigates cisplatin nephrotoxicity involving enhanced peroxisome proliferator-activated receptor-alpha (PPAR-α) expression

AIM

Despite the great efficacy reported for cisplatin as a widely used chemotherapeutic agent, its clinical use is limited by the challenge of facing its serious side effect; nephrotoxicity. In this study, the effect of the benzbromarone on peroxisome proliferator-activated receptor-alpha (PPAR-α) was investigated against cisplatin nephrotoxicity.

MAIN METHODS

Rats were administered benzbromarone (10 mg/kg/day; p.o.) for 14 days, and cisplatin (6.5 mg/kg; i.p.) as a single dose on the 10th day. Blood and kidney tissue samples were collected for determination of kidney function, biochemical and molecular markers, as well as histopathological investigation.

KEY FINDINGS

Benzbromarone improved kidney function, that was evidenced by reduced serum creatinine and blood urea nitrogen to nearly the half, compared to the group administered cisplatin alone. The protein expression of PPAR-α was enhanced with benzbromarone treatment, along with a considerable suppression of oxidative stress as benzbromarone reduced mRNA expression of NADPH oxidase, while increased the anti-oxidant HO-1 protein expression associated with enhancing Nrf2. Besides, it displayed a marked anti-inflammatory effect involved suppression of p38 MAPK/NF-κB p65 signaling pathway and its downstream targets. Moreover, benzbromarone retarded apoptosis associated with reducing the pro-apoptotic (Bax) and enhancing the anti-apoptotic (Bcl-2) protein expressions. The protective effects of benzbromarone were also confirmed by histopathological results.

SIGNIFICANCE

Our data confirm the relation between PPAR-α, and the deleterious effects induced by cisplatin. It can also be suggested that enhancing PPAR-α expression by benzbromarone is a promising therapeutic approach that overcomes cisplatin nephrotoxicity, involving regulation of different signaling pathways: Nrf2/HO-1, p38 MAPK/NF-κB p65, and Bax/Bcl-2.

The role of NLRP3 inflammasome activation in the neuroinflammatory responses to Ag2Se quantum dots in microglia

Silver selenide quantum dots (Ag₂Se QDs) provide bright prospects for the application of QDs in the field of biomedicine because they contain low-toxic compounds and show great advantages in the imaging of deep tissues and tiny vascular structures. However, the biosafety of these novel QDs has not been thoroughly evaluated, especially in one main target for toxicity-the central nervous system (CNS). Our previous studies have suggested severe inflammatory responses to cadmium-containing QDs in the hippocampus, which gives us a hint regarding the risk assessment of Ag₂Se QDs. In this study, microglial activation followed by enhanced levels of pro-inflammatory cytokines was observed in the hippocampus of mice intravenously injected with Ag₂Se QDs. When using the microglial BV2 cells to investigate the underlying mechanisms, we found that the NLRP3 inflammasome activation was involved in the IL-1β-mediated inflammation induced by Ag₂Se QDs. On the one hand, Ag₂Se QD-activated NF-κB participated in the NLRP3 inflammasome priming and assembly as well as the pro-IL-1β upregulation. On the other hand, Ag₂Se QD-induced ROS generation, particularly mtROS, triggered the NLRP3 inflammasome activation and resulted in active caspase-1 to process pro-IL-1β into mature IL-1β release. These findings not only indicated that it is important to evaluate the biosafety of novel QDs, even those containing low-toxic compounds, but also provided an unbiased and mechanism-based risk assessment of similar nanoparticles.

MicroRNA-106a Provides Negative Feedback Regulation in Lipopolysaccharide-Induced Inflammation by targeting TLR4

Acute lung injury (ALI) is a common clinical disease with high incidence and mortality rate, which is characterized by severe inflammatory response and tissues damage. MicroRNAs (miRNAs) have been regarded as novel regulators of inflammation, and play an important role in various inflammatory diseases. However, it remains unknown whether the regulatory mechanisms mediated by miR-106a is involved in LPS-induced ALI. In this study, we found that expression of miR-106a was significantly decreased in lung tissues of ALI mice and LPS-stimulated macrophages. We also revealed that over-expression of miR-106a significantly decreased the production of pro-inflammatory cytokines, including IL-1β, IL-6 and TNF-α, whereas this effect was reversed by the inhibition of miR-106a. Moreover, miR-106a inhibits NF-κB activation by targeting TLR4 expression. We further demonstrated that miR-106a inhibited TLR4 expression via binding directly to the 3'-UTR of TLR4. Taken together, the results of the present study illuminated that miR-106a is a negative feedback regulator in LPS-stimulated inflammation through TLR4/NF-κB signaling pathway.

Xanthohumol Analogues as Potent Nrf2 Activators against Oxidative Stress Mediated Damages of PC12 Cells

The nuclear factor erythroid 2-related factor 2 (Nrf2), a master transcription factor controlling a series of cytoprotective genes, is closely associated with scavenging the reactive oxygen species and maintaining the intracellular redox balance. Accumulating evidence has indicated that activation of Nrf2 is efficient to block or retard oxidative stress mediated neurodegenerative disorders. Small molecules that contribute directly or indirectly to the Nrf2 activation thus are promising therapeutic agents. Herein, we screened xanthohumol and its analogues, and two analogues (11 and 12) were disclosed to possess low cytotoxicity and rescue PC12 cells from the hydrogen peroxide or 6-hydroxydopamine induced injuries. Molecular mechanism studies demonstrated that compounds 11 and 12 are potent Nrf2 activators by promoting the nuclear accumulation of Nrf2 and enhancing the cellular antioxidant defense system. More importantly, genetically silencing the Nrf2 expression shuts down the observed cytoprotection conferred by both compounds, supporting the critical involvement of Nrf2 for the cellular actions of compounds 11 and 12.

Tetramethylpyrazine guards against cisplatin-induced nephrotoxicity in rats through inhibiting HMGB1/TLR4/NF-κB and activating Nrf2 and PPAR-γ signaling pathways

Cisplatin-induced acute renal injury is the most common and serious side effect, sometimes requiring discontinuation of the treatment. Thus, the development of new protective strategies is essential. The present study aimed to investigate the potential nephroprotective effect of tetramethylpyrazine (TMP) against acute renal damage induced by cisplatin in rats. Rats were administered 50 and 100 mg/kg TMP intraperitoneally before cisplatin (7 mg/kg). Acute nephrotoxicity was evident in cisplatin-treated rats where relative kidney weight, BUN and serum creatinine were markedly elevated. Cisplatin administration resulted in enhanced oxidative stress, evidenced by depleted GSH level as well as catalase and superoxide dismutase activities. Also, lipid peroxidation was boosted in comparison to the control. This was associated with inhibition of Nrf2 defense pathway. Moreover, cisplatin increased the expression of pro-inflammatory mediators in the kidney tissues. Cisplatin-induced apoptosis was depicted by elevated Bax mRNA expression and caspase-3 activity, as well as decreased Bcl2 mRNA expression. In addition, high mobility group box 1/toll-like receptor 4/nuclear factor-kappa B (HMGB1/TLR4/NF-κB) signaling pathway was significantly upregulated, while peroxisome proliferator-activated receptor-gamma (PPAR-γ) expression was significantly diminished in cisplatin-treated rats. Cisplatin-induced nephrotoxicity, oxidative stress, inflammation, apoptosis and the effect on Nrf2 defense pathway and HMGB1/TLR4/NF-κB as well as PPAR-γ expression were markedly ameliorated by TMP administration. Given the major nephrotoxicity of cisplatin cancer chemotherapy, TMP might be a potential candidate for neoadjuvant chemotherapy due to its antioxidant, anti-inflammatory and anti-apoptotic effects, in addition to its effect on Nrf2, HMGB1/TLR4/NF-κB signaling pathway and PPAR-γ expression.

NAG-targeting fluorescence based probe for precision diagnosis of kidney injury

NAG-targeting fluorescent probe for sensing proximal tubule cells in patient's crude urine and precision diagnosis for kidney injury unit.

Pseudoginsengenin DQ Exhibits Therapeutic Effects in Cisplatin-Induced Acute Kidney Injury via Sirt1/NF-κB and Caspase Signaling Pathway without Compromising Its Antitumor Activity in Mice

In this study, the protective effects of pseudoginsengenin DQ (PDQ) on cisplatin (CDDP)-induced nephrotoxicity were assessed, with a primary investigation into the mechanisms involved. Our results showed that pretreatment with PDQ remarkably restored levels of blood urea nitrogen (BUN) and creatinine (CRE), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Meanwhile, PDQ decreased the CDDP-induced overexpression of heme oxygenase 1 (HO-1), cytochrome P450 E1 (CYP2E1), TNF-α, nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) in renal tissues. Hoechst 33258 and TdT-mediated dUTP nick-end labeling (TUNEL) staining showed that CDDP-induced renal tubular cell apoptosis was apparently inhibited by PDQ. Western blotting showed that PDQ reversed the CDDP-induced (1) downregulation of Sirtuin-1 (Sirt-1), nuclear-related factor 2 (Nrf2), and Bcl-2, and (2) upregulation of NF-κB, Nox-4, Bax, caspase-9, and caspase-3. In addition, PDQ enhanced the antitumor activity of cisplatin in Lewis lung cancer xenograft tumor model mice. In conclusion, we found that PDQ exerted a renal protective effect against CDDP-induced acute nephrotoxicity via Sirt1/NF-κB and the caspase signaling pathway without compromising the antitumor activity of CDDP, which provides a new potential strategy for the clinical treatment of cancer and presents a new medicinal application of PDQ.