Polymyxin B exerts nephrotoxicity effects via inhibition of the Nrf2/NQO1 pathway-mediated antioxidant response.

Polymyxin B (PMB) is a polypeptide antibiotic widely used in treating multidrug-resistant Gram-negative bacteria. However, nephrotoxicity is a serious adverse effect that limits its clinical use. Therefore, clarification of the molecular mechanism of PMB-induced renal injury is essential. Our study aimed to explore possible mechanisms of PMB-induced nephrotoxicity in vivo and in vitro. Mice were treated with PMB to construct the kidney injury model. The antioxidant capacity was assessed by measuring the superoxide dismutase (SOD) and catalase (CAT) activities and the glutathione (GSH) and malondialdehyde (MDA) contents. The pathway of the nuclear factor erythroid 2-related factor 2/NADH quinone oxidoreductase 1 (Nrf2/NQO1) was examined after PMB treatment in NRK-52E cells and mice. Finally, the expressions of genes and proteins (Bax, Bcl-2, Caspase-3, Caspase-9) related to apoptosis were evaluated through quantitative polymerase chain reaction and western blot assay. The study verified PMB-induced nephrotoxicity in mice and NRK-52E cells in a dose- and time-dependent manner. PMB treatment significantly decreased the expression of Nrf2 and its downstream target gene NQO1 and increased the apoptosis-related proteins expression. In summary, our results suggested that PMB-induced oxidative stress damage by inhibiting the Nrf2/NQO1 pathway and promoting apoptosis in kidney tissues.

Spotlight on endoplasmic reticulum stress in acute kidney injury: A bibliometric analysis and visualization from 1997 to 2024.

BACKGROUND: Endoplasmic reticulum (ER) stress, a protective stress response of body and play important role in maintain ER stability. Acute kidney injury (AKI) is a severe syndrome, and the molecular mechanisms of AKI has not been fully elucidated. With an increasing understanding of ER stress, ER stress has been investigated and considered a potential and novel therapeutic target in AKI. This study aims to employ a bibliometric approach to analyze research trends and focal points in ER stress associated with AKI over 3 decades. METHODS: Data were retrieved from the Web of Science Core Collection on April 15, 2024. CiteSpace and VOSviewer bibliometric software were mainly used to measure bibliometrics and analyze knowledge graphs to predict the latest research trends in the field. RESULTS: There were 452 "ER stress in AKI" articles in the Web of Science Core Collection. According to the report, China and the United States were the leading research drivers in this field. Central South University was the most active academic institution, contributing the most documents. In this field, Dong Zheng was the most prolific author. The American Journal of Physiology-Renal Physiology was the journal with the most records among all journals. The keywords "NLRP3 inflammasome," "redox signaling," and novel forms of cell death such as "ferroptosis" may represent current research trends and directions. CONCLUSION: The bibliometric analysis comprehensively examines the trends and hotspots on "ER stress and AKI." Studies on AKI related to stress in the ER are still in their infancy. Research should focus on understanding the relationship between ER stress and inflammasome, redox signal pathways and new forms of cell death such as ferroptosis.

Unraveling Neurotoxicity Discrepancies: Comparative In vitro and In vivo Analysis of Colistin and Polymyxin B and the Underlying Mechanisms.

Polymyxins, including colistin and polymyxin B, are the final resort against Gram-negative bacterial infections. However, its clinical application is restricted due to concerns related to neurotoxicity. Despite the similar antibacterial spectrum and mode of action shared between colistin and polymyxin B, there is still a lack of definitive evidence to support the idea that their neurotoxicity profiles are identical. To comprehensively compare the neurotoxicity between colistin and polymyxin B both in vivo and in vitro and establish a theoretical foundation to guide the rational use of polymyxins within clinical settings. in vitro experiments simulated nerve damage by exposing N2a and RSC96 cells to colistin and polymyxin B. The evaluation of nerve injury included assessments of cell viability and apoptosis. To discern the variance in the mechanisms of nerve injury between colistin and polymyxin B, oxidative stress levels were examined, such as SOD, CAT, GSH, and malondialdehyde (MDA). In in vivo experiments, a rat nerve injury model was created by intraventricular injections of colistin and polymyxin B, respectively. The impact of these drugs on brain injury in rats, particularly within the hippocampus and medulla oblongata, was measured using HE and Nissl staining. The potential influence of polymyxins on the ferroptosis pathway was evaluated by assessing LPO and Fe2+ levels and the degree of mitochondrial impairment. At equivalent doses, colistin demonstrated a reduced level of neurotoxicity compared to polymyxin B, both in vitro and in vivo. in vitro experiments revealed greater cell viability and a lower apoptosis rate after colistin treatment than after polymyxin B treatment. This variance in outcomes could be attributed to the comparatively lower levels of oxidative stress associated with colistin administration. In a rat model, nerve injury resulted in observable damage to both the hippocampus and the medulla oblongata. A comprehensive assessment of the extent of damage in the CA1 to CA4 regions of the hippocampus, and the solitary tract nucleus of the medulla oblongata underscored that the neurotoxic effects of colistin remained milder compared to those elicited by polymyxin B. Even when evaluated at equivalent multiples of clinically recommended doses, colistin exhibited lower neurotoxicity in vivo than polymyxin B. For the first time, this study demonstrated the role of ferroptosis in polymyxin B-induced nerve damage. The activation levels observed within the ferroptosis pathway due to polymyxin B exceeded those triggered by colistin. Colistin exhibited a marked reduction in neurotoxicity compared to polymyxin B, evident in both the equivalent and clinically recommended doses. These findings suggest that, from the perspective of neurotoxicity, colistin presents a more favorable option for clinical use.

Advances in Ferroptosis-Inducing Agents by Targeted Delivery System in Cancer Therapy.

Currently, cancer remains one of the most significant threats to human health. Treatment of most cancers remains challenging, despite the implementation of diverse therapies in clinical practice. In recent years, research on the mechanism of ferroptosis has presented novel perspectives for cancer treatment. Ferroptosis is a regulated cell death process caused by lipid peroxidation of membrane unsaturated fatty acids catalyzed by iron ions. The rapid development of bio-nanotechnology has generated considerable interest in exploiting iron-induced cell death as a new therapeutic target against cancer. This article provides a comprehensive overview of recent advancements at the intersection of iron-induced cell death and bionanotechnology. In this respect, the mechanism of iron-induced cell death and its relation to cancer are summarized. Furthermore, the feasibility of a nano-drug delivery system based on iron-induced cell death for cancer treatment is introduced and analyzed. Secondly, strategies for inducing iron-induced cell death using nanodrug delivery technology are discussed, including promoting Fenton reactions, inhibiting glutathione peroxidase 4, reducing low glutathione levels, and inhibiting system Xc-. Additionally, the article explores the potential of combined treatment strategies involving iron-induced cell death and bionanotechnology. Finally, the application prospects and challenges of iron-induced nanoagents for cancer treatment are discussed.

Piceatannol-3'-O-ß-D-glucopyranoside attenuates colistin-induced neurotoxicity by suppressing oxidative stress via the NRF2/HO-1 pathway.

BACKGROUND: Multidrug-resistant Gram-negative bacteria are the most pressing problem in treating infectious diseases. As one of the primary drugs for multidrug-resistant Gram-negative bacteria, the neurotoxicity of colistin has become a significant challenge in clinical practice. PURPOSE: This study aimed to investigate the potential effect of piceatannol-3'-O-ß-D glucopyranoside (PG) on colistin-induced neurotoxicity and the underlying mechanism. METHODS: In vitro, nerve cell damage models were established by exposing N2a cells to 400 µM colistin for 24 h. The effects of PG on cell viability, apoptosis level, and oxidative stress level were analyzed. A western blot experiment was performed to determine the NRF2 pathway, apoptosis, and autophagy-related proteins. Mitochondrial morphology and mitochondrial membrane potential were detected after staining using laser confocal microscopy. In vivo, nerve injury mouse model was established by intracerebroventricular colistin administration. Morphological changes in brain tissues were observed using HE and Nissl staining. RESULTS: PG significantly reduced colistin-induced neuronal apoptosis levels. The apoptosis-related protein expressions were suppressed after PG intervention. Mechanistically, PG increased the levels of antioxidant factors and decreased the levels of oxidative factors, which might be related to the activation of the NRF2 pathway. In addition, PG treatment reversed the deviations in mitochondrial morphology and membrane potential. PG suppressed autophagy levels in N2a cells, possibly because PG inhibited colistin-induced apoptosis, thus reducing the level of spontaneous protective autophagy in cells. Nrf2 knockdown N2a cell models were applied to confirm that the activation of the NRF2 pathway played a vital role in PG alleviating the nerve damage caused by colistin. CONCLUSION: PG is a potential treatment option for colistin-induced neurotoxicity. It mitigated colistin-induced oxidative stress-associated injury and mitochondrial damage by activating the NRF2/HO-1 pathway, thus reducing nerve cell apoptosis.

Curcumin nicotinate decreases serum LDL cholesterol through LDL receptor-mediated mechanism.

Curcumin nicotinate (Curtn) is a synthesized ester derivative of curcumin and niacin. Our previous study has shown that Curtn lowers serum low-density lipoprotein cholesterol (LDL-C) levels in apoE-/- mice and promotes LDL-C uptake into HepG2 cells in vitro. The present study was to test the hypothesis that Curtn decreases serum LDL-C levels through decreased expression of pro-protein convertase subtilisin/kexin type 9 (PCSK9) and subsequent increase in LDL receptor expression. Male Wistar rats on high-fat diet (HFD) were treated with Curtn or rosuvastatin. Curtn or rosuvastatin treatment significantly decreased serum levels of total cholesterol (TC) and LDL-C in rats on HFD with increased liver LDL receptor expression. LDL-C-lowering effect of Curtn was not observed in LDL receptor deficient (LDLR-/-) mice on HFD, while rosuvastatin still decreased serum lipid levels in LDLR-/- mice, indicating that the reduction of serum LDL-C levels by Curtn treatment was LDL receptor-dependent. Curtn treatment also significantly decreased the protein expression of PCSK9 in Wistar rats and LDLR-/- mice. In HepG2 cells with overexpression of human PCSK9, Curtn treatment significantly increased LDL-C uptakes into hepatocytes, and increased LDL receptor distribution on cell surface in association with decreased PCSK9 protein expression. RNAi-LDLR significantly attenuated the effect of Curtn on LDLR distribution on cell surface. These data indicates that Curtn would decrease serum LDL-C level at least partially through inhibition of PCSK9 expression, and subsequent increase in LDL receptor expression and distribution in hepatocytes, serving as a potential novel compound to treat hyperlipidemia.

Different Effects of Endothelial Extracellular Vesicles and LPS-Induced Endothelial Extracellular Vesicles on Vascular Smooth Muscle Cells: Role of Curcumin and Its Derivatives.

Background: During the progression of atherosclerosis (AS), the vascular endothelial and smooth muscle cells are reciprocally regulated by extracellular vesicles (EVs). EVs have different effects on pathological and physiological processes due to the different cargoes contained in EVs. Purpose: To study the effects of endothelial cells-derived EVs on normal and inflammatory conditions. To investigate the effects of curcumin and curcumin derivatives (Nicotinic-curcumin) on endothelial EVs. Methods: EVs were isolated from human umbilical vein endothelial cells (HUVECs) by ultracentrifugation. To examined the effect of normal and LPS-induced endothelial cells-derived EVs on the proliferation of human aortic smooth muscle cells (HASMCs), the CCK-8 assay was performed. Transwell and wound healing assays were conducted to assess cell migration. The effects of EVs on lipid accumulation following treatment with oxidized low-density lipoprotein (Ox-LDL) were evaluated with the oil red O staining assay and HPLC. The number of EVs was calculated using the nanoparticle tracking analysis (NTA) and BCA. The expression levels of Rab27a and Rab27b that regulate the EVs secretion were measured by Western blotting assay. The differential expression of miRNAs in endothelial EVs and LPS-induced endothelial EVs was analyzed using miRNA-Sequencing (miRNA-Seq) and RT-PCR. Results: Treatment with endothelial EVs reduced the proliferation and migration of HASMCs as well as lipid accumulation in HASMCs. However, treatment with LPS-induced endothelial EVs did not inhibit the migration of HASMCs or lipid accumulation, instead it promoted the proliferation of HASMCs. Treatment with the two types of EVs induced differential expression of several miRNAs, including miR-92a-3p, miR-126-5p, miR-125a-3p, miR-143-3p, etc. Moreover, 1 µg/mL LPS induction greatly increased secretion of endothelial EVs. Treatment with curcumin and nicotinic-curcumin reduced endothelial EVs secretion, possibly by inhibiting inflammation. Conclusion: Endothelial EVs may confer beneficial effects on atherosclerosis by regulating vascular smooth muscle cell (VSMCs), whereas pro-inflammatory factors may disrupt this effect.

Curcumin: From a controversial "panacea" to effective antineoplastic products.

BACKGROUND: Curcumin, a controversial "panacea," has been broadly studied. Its bioactivities including antioxidant, anti-inflammatory, and especially antineoplastic activities have been documented. However, due to its extensive bioactivities, some scientists hold a skeptical point of view toward curcumin and described curcumin as a "deceiver" to chemists. The objective of this study was to explore curcumin's another possibility as a potential supplementary leading compound to cancer treatments. METHODS: Literature searches were conducted using electronic databases. Search terms such as "curcumin," "curcumin analogues," and so on were used. The literatures were collected and summarized. In this article, reported targets of curcumin are reviewed. The limitations of a curcumin as a therapeutic anticancer product including low bioavailability and poor targeting are mentioned. Furthermore, modified curcumin analogues and antitumor mechanisms are listed and discussed in the aspects of cell death and tumor microenvironment including angiogenesis, tissue hypoxia status, and energy metabolism. RESULTS: Several possible modification strategies were presented by analyzing the relationships between the antitumor activity of curcumin analogues and their structural characteristics, including the introduction of hydrophilic group, shortening of redundant hydrocarbon chain, the introduction of extra chemical group, and so on. CONCLUSIONS: From our perspective, after structural modification curcumin could be more effective complementary product for cancer therapies by the enhancement of targeting abilities and the improvement of bioavailability.

A novel recombinant peptide INSR-IgG4Fc (Yiminsu) restores insulin sensitivity in experimental insulin resistance models.

Type 2 diabetes mellitus (T2DM) is a chronic degenerative endocrine and metabolic disease with high mortality and morbidity, yet lacks effective therapeutics. We recently generated a novel fusion peptide INSR-IgG4Fc, Yiminsu (YMS), to facilitate the high-affinity binding and transportation of insulin. Thus, the aim of the present study was to determine whether the novel recombinant peptide, YMS, could contribute to restoring insulin sensitivity and glycaemic control in insulin resistance models and revealing its underlying mechanism. Palmitic acid (PA)-treated LO2 cells and high fat diet (HFD)-fed mice were treated with YMS. Therapeutic effects of YMS were measured using Western blotting, ELISA, qPCR, Histology and transmission electron microscopy. We observed that YMS treatment effectively improved insulin signaling in PA-treated LO2 cells and HFD-fed mice. Notably, YMS could significantly reduce serum levels of glucose, triglycerides, fatty acids and cholesterol without affecting the serum insulin levels. Moreover, our data demonstrated that YMS could restore glucose and lipid homeostasis via facilitating insulin transportation and reactivating PI3K/Akt signaling in both PA-treated cells and liver, gastrocnemius and brown fat of HFD-fed mice. Additionally, we noticed that the therapeutic effects of YMS was similar as rosiglitazone, a well-recognized insulin sensitizer. Our findings suggested that YMS is a potentially candidate for pharmacotherapy for metabolic disorders associated with insulin resistance, particularly in T2DM.

[Effects of the extracts from Ajuga decumbens on anti-fatigue in mice].

OBJECTIVE: To investigate the effects of extracts from Ajuga decumbens on anti-fatigue in mice. METHODS: One hundred and twenty female Kunming (KM) mice were randomly divided into quiet control group, sport control group, positive control group and 3 experimental groups which were the low, medium and high dose group given the extracts from Ajuga decumbens. The low, medium and high dose group were given the extracts with 100 mg/kg, 200 mg/kg, 400 mg/kg by body weight of mice for 30 d, respectively, but the positive control group was given American ginseng granules, while the quiet control group and the sport control groups were treated with saline. After this, the exhausting time, the physio-biochemical indexes (including lactic acid, blood urea nitrogen, blood sugar, total cholesterol and triglyceride) in serum, the contents of muscle and liver glycogen, and the antioxidative indexes (including glutathione peroxidase, superoxide dismutase, catalase and malondialdehyde) of organs in mice were investigated. RESULTS: The exhausting time, the number of red blood cell, the contents of hemoglobin and blood sugar, the contents of muscle and liver glycogen, and the activities of glutathione peroxidase, superoxide dismutase and catalase in organs of mice in the medium dose group and the high dose group were significantly more than those of the sport control group, but the contents of blood lactic acid, blood urea nitrogen and that of triglyceride and total cholesterol in serum, and the content of malondialdehyde in organs of mice in the medium dose group and the high dose group were significantly lower than those of the sport control group. And the effect of medium dose extracts from Ajuga decumbens on anti-fatigue was better than that of American ginseng granules. CONCLUSIONS: The extracts from Ajuga decumbens has significant anti-fatigue effect in mice.

[Effects of Lonicera Japonica flavone on immunomodulation in mice].

OBJECTIVE: To study immunomodulating activity of Lonicera Japonica flavone by investigating immune enzymatic activity of serum and antoxidized activity of lymphoid organs in mice. METHODS: Fifty KM mice were randomly divided into control group, model group, low dose group, middle dose group and high dose group(n = 10), respectively. And low dose group, middle dose group and high dose group were given Lonicera Japonica flavone with 100 mg/kg, 200 mg/kg and 400 mg/kg every day, respectively, while control group and model group were administered with NS. After continuously giving drug 7 weeks, other groups were injected with Dexamethasome (Dex: 25 mg /kg) for 3 days by subcutaneous injection, but the control group were treated with NS. And after giving Lonicera Japonica flavone 1 week simultaneously, organ indexes , the activity of acid phosphatase (ACP), alkaline phosphatase (AKP) and lysozyme (LSZ) in serum , and the content of monoamine oxidase (MAO), total antioxidant capacity (T-AOC), total superoxide dismutase (SOD) and malondialdehyde (MDA) in lymphoid organs in mice were tested, respectively. RESULTS: Lonicera Japonica flavone could significantly improve the organ indexes, and significantly improve the activity of ACP, AKP and LSZ in serum, and significantly improve the contents of T-AOC and SOD, but reduce that of MAO and MDA in lymphoid organs in immunosuppressed mice. CONCLUSION: Ionicera Japonica flavone can significantly improve the activity of immune enzyme in serum and the antioxidized activity of lymphoid organs in mice. It suggests that Ionicera Japonica flavone has a good immunomodulatory effects.