Schisantherin A attenuates sepsis-induced acute kidney injury by suppressing inflammation via regulating the NRF2 pathway

Clemastine mitigates sepsis-induced acute kidney injury in rats; the role of α-Klotho/TLR-4/MYD-88/NF-κB/ Caspase-3/ p-P38 MAPK signaling pathways

Sepsis is a fatal condition, with an annual incidence of more than 48 million cases as well as 11 million deaths resulting from it. Moreover, sepsis continues to rank as the fifth most prevalent cause of mortality globally. The objective of this study is to investigate if Clemastine (CLM) pretreatment protects against acute kidney injury (AKI) caused by cecal ligation and puncture (CLP) via modulating Toll-like receptor-4 (TLR-4), Myeloid differentiation primary response 88 (MYD-88), nuclear factor kappa B (NF-κB), Bcl-2-associated X (Bax), B-cell lymphoma-2 (Bcl-2), and caspase-3 signaling pathways. CLM markedly attenuated sepsis-caused molecular, biochemical, and histopathological alterations. CLM downregulated the levels of the proinflammatory markers, suppressed the expression of cleaved caspase-3, TLR-4 and MYD-88 as well as inactivating NF-κB p-P65 and p-P38 proteins, inhibited Bax, NF-κB, and caspase-3 genes expression, and augmented α-Klotho protein expression as well as Bcl-2 gene expression. Finally, CLM pretreatment protected against acute kidney injury by preventing TLR-4/p-P38 pathway-mediated apoptotic cell death in rats.

Anti-pneumoconiosis effect of schisantherin A in PMA-induced A549 cells and SiO2/TiO2nanoparticles-induced acute pulmonary injury in mice

There has been significant global interest in respiratory health driven by the coronavirus disease (COVID-19) and severe environmental pollution. This study explored the potential of schisantherin A (SchA), a compound derived from Schisandra chinensis, to protect against acute pneumoconiosis. We assessed the effects of SchA on phorbol 12-myristate 13-acetate (PMA)-stimulated A549 alveolar epithelial cells and SiO2/TiO2-induced pulmonary injury in mice. In A549 cells, SchA significantly decreased pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and interleukin (IL)-8 levels. SchA-mediated reduction in inflammatory mediators was associated with the downregulation of PMA-stimulated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling activation. In SiO2/TiO2-induced lung-injured mice, SchA administration significantly reduced MUC5AC production in lung tissue. SchA administration significantly downregulated the overexpression of NK-κB and the subsequent production of COX-2, iNOS, and NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasomes. It significantly suppressed expected increases in total cell numbers and pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and IL-1β in the bronchoalveolar lavage fluid (BALF) in SiO2/TiO2-stimulated mice. In contrast, the SiO2/TiO2-mediated decrease in IL-10 levels was significantly improved by SchA treatment. These fundamental results can be used to develop potential treatments involving SchA for acute pneumoconiosis.

The promising antioxidant effects of lignans: Nrf2 activation comes into view

Lignans are biologically active compounds widely distributed, recognized, and identified in seeds, fruits, and vegetables. Lignans have several intriguing bioactivities, including anti-inflammatory, antioxidant, and anticancer activities. Nrf2 controls the expression of many cytoprotective genes. Activation of Nrf2 is a promising therapeutic approach for treating and preventing diseases resulting from oxidative injury and inflammation. Lignans have been demonstrated to stimulate Nrf2 signaling in a variety of in vitro and experimental animal models. The review summarizes the findings of fourteen lignans (Schisandrin A, Schisandrin B, Schisandrian C, Magnolol, Honokiol, Sesamin, Sesamol, Sauchinone, Pinoresinol, Phyllanthin, Nectandrin B, Isoeucommin A, Arctigenin, Lariciresinol) as antioxidative and anti-inflammatory agents, affirming how Nrf2 activation affects their pharmacological effects. Therefore, lignans may offer therapeutic candidates for the treatment and prevention of various diseases and may contribute to the development of effective Nrf2 modulators.

Dihydromyricetin Nanoparticles Alleviate Lipopolysaccharide-Induced Acute Kidney Injury by Decreasing Inflammation and Cell Apoptosis via the TLR4/NF-κB Pathway

Acute kidney injury (AKI) is the most severe and fatal complication of sepsis resulting from infectious trauma. Currently, effective treatment options are still lacking. Dihydromyricetin is the main component extracted from Vine tea (Ampelopsis megalophylla Diels et Gilg). In our previous research, chitosan-tripolyphosphate-encapsulated nanoparticles of dihydromyricetin (CS-DMY-NPs) have been proven to have potential protective effects against cisplatin-induced AKI. Here, we investigated the protective effects and mechanisms of DMY and its nano-formulations against LPS-induced AKI by assessing pathological and inflammatory changes in mice. In mice with LPS-AKI treated with 300 mg/kg CS-DMY-NPs, the levels of creatinine (Cr), blood urea nitrogen (BUN), and KIM-1 were significantly reduced by 56%, 49%, and 88%, respectively. CS-DMY-NPs can upregulate the levels of GSH, SOD, and CAT by 47%, 7%, and 14%, respectively, to inhibit LPS-induced oxidative stress. Moreover, CS-DMY-NPs decreased the levels of IL-6, IL-1β, and MCP-1 by 31%, 49%, and 35%, respectively, to alleviate the inflammatory response. TUNEL and immunohistochemistry showed that CS-DMY-NPs reduced the number of apoptotic cells, increased the Bcl-2/Bax ratio by 30%, and attenuated renal cell apoptosis. Western blot analysis of renal tissue indicated that CS-DMY-NPs inhibited TLR4 expression and downregulated the phosphorylation of NF-κB p65 and IκBα. In summary, DMY prevented LPS-induced AKI by increasing antioxidant capacity, reducing inflammatory responses, and blocking apoptosis, and DMY nanoparticles were shown to have a better protective effect for future applications.

Natural products: A potential immunomodulators against inflammatory-related diseases

The incidence and prevalence of inflammatory-related diseases (IRDs) are increasing worldwide. Current approved treatments for IRDs in the clinic are combat against inhibiting the pro-inflammatory cytokines. Though significant development in the treatment in the IRDs has been achieved, the severe side effects and inefficiency of currently practicing treatments are endless challenge. Drug discovery from natural sources is efficacious over a resurgence and also natural products are leading than the synthetic molecules in both clinical trials and market. The use of natural products against IRDs is a conventional therapeutic approach since it is a reservoir of unique structural chemistry, accessibility and bioactivities with reduced side effects and low toxicity. In this review, we discuss the cause of IRDs, treatment of options for IRDs and the impact and adverse effects of currently practicing clinical drugs. As well, the significant role of natural products against various IRDs, the limitations in the clinical development of natural products and thus pave the way for development of natural products as immunomodulators against IRDs are also discussed.

Urea nitrogen-to-albumin ratio predicts ventricular aneurysm formation in ST-segment elevation myocardial infarction

AIMS

Left ventricular aneurysm (LVA) is an important complication of acute myocardial infarction. The aim of this study was to investigate the possible predictive value of blood urea nitrogen-to-albumin ratio (BAR) for the LVA formation in acute ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A total of 1123 consecutive patients with STEMI were prospectively enrolled. The clinical and laboratory data were compared between LVA group and non-LVA group. Multivariable logistic regression analysis was performed to assess the independent risk factors of LVA formation. Predictive power of BAR and composite variable for LVA formation were assessed using receiver operating characteristic curve. LVA was detected in 162 patients (14.4%). The BAR was significantly higher in patients with LVA [0.16 (0.13-0.19) vs. 0.13 (0.10-0.17), P < 0.001]. Multivariable logistic regression analysis revealed that left ventricular ejection fraction (LVEF) [odds ratio (OR) = 0.865, P < 0.001], culprit vessel-left anterior descending artery (LAD) (OR = 4.705, P < 0.001), and BAR (OR = 2.208, P = 0.018) were all independent predictors for LVA formation. The predictive value of BAR remained significant even after cross-validation by splitting population into training set (OR = 1.957, P = 0.034) and validation set (OR = 1.982, P = 0.039). The maximal length and width of LVA were significantly increased in patients with BAR ≥ 0.15 when compared with BAR < 0.15 (3.37 ± 1.09 vs. 2.92 ± 0.93, P = 0.01, for maximal length, and 2.20 ± 0.55 vs. 1.85 ± 0.63, P = 0.001, for maximal width). The discriminant power of BAR for LVA is 0.723, which is superior to both blood urea nitrogen (C statistic = 0.586, P < 0.001) and albumin (C statistic = 0.64, P < 0.001). The combination of BAR, LVEF, and culprit vessel-LAD could significantly increase the predictive ability (C statistic = 0.874, P < 0.001, for vs. BAR). Subgroup analysis of age, sex, hypertension, diabetes, smoking, LVEF, serum albumin, multiple-vessel disease, and Gensini score had no effect on the association between BAR and risk of LVA formation (P < 0.05 for all subgroups).

CONCLUSIONS

A higher BAR was an independent predictor for LVA formation in STEMI patients with primary PCI.

Schisandrin A alleviates renal fibrosis by inhibiting PKCβ and oxidative stress

BACKGROUND

Renal fibrosis is a common pathway that drives the advancement of numerous kidney maladies towards end-stage kidney disease (ESKD). Suppressing renal fibrosis holds paramount clinical importance in forestalling or retarding the transition of chronic kidney diseases (CKD) to renal failure. Schisandrin A (Sch A) possesses renoprotective effect in acute kidney injury (AKI), but its effects on renal fibrosis and underlying mechanism(s) have not been studied.

STUDY DESIGN

Serum biochemical analysis, histological staining, and expression levels of related proteins were used to assess the effect of PKCβ knockdown on renal fibrosis progression. Untargeted metabolomics was used to assess the effect of PKCβ knockdown on serum metabolites. Unilateral Ureteral Obstruction (UUO) model and TGF-β induced HK-2 cells and NIH-3T3 cells were used to evaluate the effect of Schisandrin A (Sch A) on renal fibrosis. PKCβ overexpressed NIH-3T3 cells were used to verify the possible mechanism of Sch A.

RESULTS

PKCβ was upregulated in the UUO model. Knockdown of PKCβ mitigated the progression of renal fibrosis by ameliorating perturbations in serum metabolites and curbing oxidative stress. Sch A alleviated renal fibrosis by downregulating the expression of PKCβ in kidney. Treatment with Sch A significantly attenuated the upregulated proteins levels of FN, COL-I, PKCβ, Vimentin and α-SMA in UUO mice. Moreover, Sch A exhibited a beneficial impact on markers associated with oxidative stress, including MDA, SOD, and GSH-Px. Overexpression of PKCβ was found to counteract the renoprotective efficacy of Sch A in vitro.

CONCLUSION

Sch A alleviates renal fibrosis by inhibiting PKCβ and attenuating oxidative stress.

Cardioprotective effects of Schisantherin A against isoproterenol-induced acute myocardial infarction through amelioration of oxidative stress and inflammation via modulation of PI3K-AKT/Nrf2/ARE and TLR4/MAPK/NF-κB pathways in rats

BACKGROUND AND AIMS

The scientific community is concerned about cardiovascular disease mortality and morbidity, especially myocardial infarction (MI). Schisantherin A (SCA), a dibenzocyclooctadiene lignan monomer found in S. chinensis fruits has cardiovascular advantages such as increasing NO production in isolated rat thoracic aorta and reducing heart damage caused by ischemia-reperfusion (I/R) through decreasing apoptosis. The present study was undertaken to explore the potential effects of SCA on ISO-induced myocardial infarction in rats.

METHODS

Rats were randomly allocated to four groups: control; ISO-treated, and two additional groups of ISO + SCA (5 or 10 mg/kg body weight). All SCA-treated groups were administered with SCA for 20 days and all ISO groups were challenged with ISO on days 19 and 20.

RESULTS

SCA significantly attenuated ISO-induced rise in heart/body weight ratio, myocardial infarct size, and cardiac functional biomarkers (CK-MB, cTnI and BNP). SCA pre- and co-treatment resulted in a significant reduction in oxidative stress (via MDA, NO and GSH and increased activities of SOD, CAT and GPx) and inflammation (via decreased levels of TNF-α, IL-6 and IL-1β) markers when compared to the same levels in cardiac tissue of ISO-treated rats. This study also showed that SCA protects ISO-induced oxidative stress and inflammation by activating the PI3K-AKT/Nrf2/ARE pathway and suppressing TLR4/MAPK/NF-κB pathways. Furthermore, SCA treatment protected histopathological alterations observed in only ISO-treated cardiac transverse sections of rats.

CONCLUSION

In conclusion, the findings of this study suggest that SCA protects against cardiac injury in the ISO-induced MI model of rats.

Schisandrin A ameliorates increased pulmonary capillary endothelial permeability accompanied with sepsis through inhibition of RhoA/ROCK1/MLC pathways

BACKGROUND

Sepsis is a systemic inflammatory response, and vascular leakage associated with acute lung injury (ALI) is an important pathophysiological process during sepsis. Schisandrin A (SchA) is a bioactive lignan which has been reported to have the anti-inflammatory effects in many studies, while whether SchA can ameliorate ALI-related vascular leakage caused by sepsis is unknown.

OBJECTIVE

To evaluate the role and the underlying mechanism of SchA in increase of pulmonary vascular permeability induced by sepsis.

METHODS

The effect of SchA on pulmonary vascular permeability was examined in rat acute lung injury model. The effect of SchA on skin vascular permeability of mice was investigated through Miles assay. MTT assay was performed to detect the cell activity, and transwell assay was used to detect the effect of SchA on cell permeability. The effects of SchA on junction proteins and RhoA/ROCK1/MLC signaling pathway were manifested by immunofluorescence staining and western blot.

RESULTS

The administration of SchA alleviated rat pulmonary endothelial dysfunction, relieved increased permeability in the mouse skin and HUVECs induced by lipopolysaccharide (LPS). Meanwhile, SchA inhibited the formation of stress fibers, reversed the decrease of expression of ZO-1 and VE-cadherin. Subsequent experiments confirmed that SchA inhibited RhoA/ROCK1/MLC canonical pathway in rat lungs and HUVECs induced by LPS. Moreover, overexpression of RhoA reversed the inhibitory effect of SchA in HUVECs, which suggested that SchA protected the pulmonary endothelial barrier by inhibiting RhoA/ROCK1/MLC pathway.

CONCLUSION

In summary, our results indicate that SchA ameliorates the increase of pulmonary endothelial permeability induced by sepsis through inhibition of RhoA/ROCK1/MLC pathway, providing a potentially effective therapeutic strategy for sepsis.

Exosomal microRNA-342-5p secreted from adipose-derived mesenchymal stem cells mitigates acute kidney injury in sepsis mice by inhibiting TLR9

BACKGROUND

Sepsis-related acute kidney injury (AKI) is an inflammatory disease associated with extremely high mortality and health burden. This study explored the possibility of exosomes secreted by adipose-derived mesenchymal stem cells (AMSCs) serving as a carrier for microRNA (miR)-342-5p to alleviate sepsis-related AKI and investigated the possible mechanism.

METHODS

Serum was obtained from 30 patients with sepsis-associated AKI and 30 healthy volunteers for the measurement of miR-342-5p, blood urea nitrogen (BUN), and serum creatinine (SCr) levels. For in vitro experiments, AMSCs were transfected with LV-miR-342-5p or LV-miR-67 to acquire miR-342-5p-modified AMSCs and miR-67-modified AMSCs, from which the exosomes (AMSC-Exo-342 and AMSC-Exo-67) were isolated. The human renal proximal tubular epithelial cell line HK-2 was induced by lipopolysaccharide (LPS) to construct a cellular model of sepsis. The expression of Toll-like receptor 9 (TLR9) was also detected in AKI cells and mouse models. The interaction between miR-342-5p and TLR9 was predicted by dual luciferase reporter gene assay.

RESULTS

Detection on clinical serum samples showed that BUN, SCr, and TLR9 were elevated and miR-342-5p level was suppressed in the serum of patients with sepsis-associated AKI. Transfection with LV-miR-342-5p reinforced miR-342-5p expression in AMSCs and AMSC-secreted exosomes. miR-342-5p negatively targeted TLR9. LPS treatment enhanced TLR9 expression, reduced miR-342-5p levels, suppressed autophagy, and increased inflammation in HK-2 cells, while the opposite trends were observed in LPS-induced HK-2 cells exposed to AMSC-Exo-342, Rapa, miR-342-5p mimic, or si-TLR9. Additionally, the effects of AMSC-Exo-342 on autophagy and inflammation in LPS-induced cells could be weakened by 3-MA or pcDNA3.1-TLR9 treatment. Injection of AMSC-Exo-342 enhanced autophagy, mitigated kidney injury, suppressed inflammation, and reduced BUN and SCr levels in sepsis-related AKI mouse models.

CONCLUSION

miR-342-5p transferred by exosomes from miR-342-5p-modified AMSCs ameliorated AKI by inhibiting TLR9 to accelerate autophagy.

Cytoprotective remedies for ameliorating nephrotoxicity induced by renal oxidative stress

AIMS

Nephrotoxicity is the hallmark of anti-neoplastic drug metabolism that causes oxidative stress. External chemical agents and prescription drugs release copious amounts of free radicals originating from molecular oxidation and unless sustainably scavenged, they stimulate membrane lipid peroxidation and disruption of the host antioxidant mechanisms. This review aims to provide a comprehensive collection of potential cytoprotective remedies in surmounting the most difficult aspect of cancer therapy as well as preventing renal oxidative stress by other means.

MATERIALS AND METHODS

Over 400 published research and review articles spanning several decades were scrutinised to obtain the relevant data which is presented in 3 categories; sources, mechanisms, and mitigation of renal oxidative stress.

KEY-FINDINGS

Drug and chemical-induced nephrotoxicity commonly manifests as chronic or acute kidney disease, nephritis, nephrotic syndrome, and nephrosis. Renal replacement therapy requirements and mortalities from end-stage renal disease are set to rapidly increase in the next decade for which 43 different cytoprotective compounds which have the capability to suppress experimental nephrotoxicity are described.

SIGNIFICANCE

The renal system performs essential homeostatic functions that play a significant role in eliminating toxicants, and its accumulation and recurrence in nephric tissues results in tubular degeneration and subsequent renal impairment. Global statistics of the latest chronic kidney disease prevalence is 13.4 % while the end-stage kidney disease requiring renal replacement therapy is 4-7 million per annum. The remedial compounds discussed herein had proven efficacy against nephrotoxicity manifested consequent to impaired antioxidant mechanisms in preclinical models produced by renal oxidative stress activators.

Protocatechuic acid ameliorates lipopolysaccharide-induced kidney damage in mice via downregulation of TLR-4-mediated IKBKB/NF-κB and MAPK/Erk signaling pathways

Acute kidney injury (AKI) is a very critical cause of death in the whole world. Lipopolysaccharide (LPS) induces kidney damage by activating various deleterious inflammatory and oxidative pathways. Protocatechuic acid, a natural phenolic compound, has shown to exert beneficial effects against oxidative and inflammatory responses. The study aimed to clarify the nephroprotective activity of protocatechuic acid in LPS-induced acute kidney damage in mice. Forty male Swiss mice were allocated in four groups as follows: normal control group; LPS (250 μg/kg, ip)-induced kidney injury group; LPS-injected mice treated with protocatechuic acid (15 mg/kg, po), and LPS-injected mice treated with protocatechuic acid (30 mg/kg, po). Significant toll-like receptor 4 (TLR-4)-mediated activation of IKBKB/NF-κB and MAPK/Erk/COX-2 inflammatory pathways has been observed in kidneys of mice treated with LPS. Oxidative stress was revealed by inhibition of total antioxidant capacity, catalase, nuclear factor erythroid 2-related factor 2 (Nrf2), and NAD(P)H quinone oxidoreductase (NQO1) enzyme along with increased nitric oxide level. In parallel, focal inflammatory effects were shown in between the tubules and glomeruli as well as in the perivascular dilated blood vessels at the cortex affecting the normal morphology of the kidney tissues of LPS-treated mice. However, treatment with protocatechuic acid reduced LPS-induced changes in the aforementioned parameters and restored normal histological features of the affected tissues. In conclusion, our study uncovered that protocatechuic acid has nephroprotective effects in mice with AKI through opposing different inflammatory and oxidative cascades.

Metabolic profiling on the analysis of different parts of Schisandra chinensis based on UPLC-QTOF-MS with comparative bioactivity assays

The Schisandra chinensis is an important edible plant, and previous phytochemical research focused on the S. chinensis fruit (SF) due to its long history as traditional Chinese medicine. Schisandra chinensis fruit was used as an astringent tonic to astringe the lungs and the kidneys, replenish energy, promote the production of body fluids, tonify the kidney, and induce sedation. The components of S. chinensis, such as its stems (SS), leaves (SL), and roots (SR), have drawn little attention regarding their metabolites and bioactivities. In this study, a strategy of combining a chemical database with the Progenesis QI informatics platform was applied to characterize the metabolites. A total of 332 compounds were tentatively identified, including lignans, triterpenoids, flavonoids, tannins, and other compound classes. Heatmap and principal component analysis (PCA) showed remarkable differences in different parts of the plants. By multiple orthogonal partial least-squares discriminant analyses (OPLS-DA), 76 compounds were identified as potential marker compounds that differentiate these different plant parts. Based on the variable influence on the projection score from OPLS-DA, the active substances including gomisin D, schisandrol B, schisantherin C, kadsuranin, and kadlongilactone F supported the fact that the biological activity of the roots was higher than that of the fruit. These substances can be used as marker compounds in the plant roots, which likely contribute to their antioxidant and anti-inflammatory activities. The plant roots could be a new medicinal source that exhibits better activity than that of traditional medicinal parts, which makes them worth exploring.

Schisantherin A inhibits cell proliferation by regulating glucose metabolism pathway in hepatocellular carcinoma

Schisantherin A (STA) is a traditional Chinese medicine extracted from the plant Schisandra chinensis, which has a wide range of anti-inflammatory, antioxidant, and other pharmacological effects. This study investigates the anti-hepatocellular carcinoma effects of STA and the underlying mechanisms. STA significantly inhibits the proliferation and migration of Hep3B and HCCLM3 cells in vitro in a concentration-dependent manner. RNA-sequencing showed that 77 genes are upregulated and 136 genes are downregulated in STA-treated cells compared with untreated cells. KEGG pathway analysis showed significant enrichment in galactose metabolism as well as in fructose and mannose metabolism. Further gas chromatography-mass spectrometric analysis (GC-MS) confirmed this, indicating that STA significantly inhibits the glucose metabolism pathway of Hep3B cells. Tumor xenograft in nude mice showed that STA has a significant inhibitory effect on tumor growth in vivo. In conclusion, our results indicate that STA can inhibit cell proliferation by regulating glucose metabolism, with subsequent anti-tumor effects, and has the potential to be a candidate drug for the treatment of liver cancer.

Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) ameliorates sepsis-associated acute kidney injury by maintaining mitochondrial homeostasis and improving the mitochondrial function

Mitochondrial dysfunction has a role in sepsis-associated acute kidney injury (S-AKI), so the restoration of normal mitochondrial homeostasis may be an effective treatment strategy. Transcription factor nuclear factor erythroid 2 p45-related factor 2 (NRF2) is a main regulator of cell-redox homeostasis, and recent studies reported that NRF2 activation helped to preserve mitochondrial morphology and function under conditions of stress. However, the role of NRF2 in the process of S-AKI is still not well understood. The present study investigated whether NRF2 regulates mitochondrial homeostasis and influences mitochondrial function in S-AKI. We demonstrated activation of NRF2 in an in vitro model: lipopolysaccharide (LPS) challenge of ductal epithelial cells of rat renal tubules (NRK-52e cells), and an in vivo model: cecal ligation and puncture (CLP) of rats. Over-expression of NRF2 attenuated oxidative stress, apoptosis, and the inflammatory response; enhanced mitophagy and mitochondrial biogenesis; and mitigated mitochondrial damage in the in vitro model. In vivo experiments showed that rats treated with an NRF2 agonist had higher adenosine triphosphate (ATP) levels, lower blood urea nitrogen and creatinine levels, fewer renal histopathological changes, and higher expression of mitophagy-related proteins [PTEN-induced putative kinase 1 (PINK1), parkin RBR E3 ubiquitin protein ligase (PRKN), microtubule-associated protein 1 light chain 3 II (LC3 II)] and mitochondrial biogenesis-related proteins [peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α) and mitochondrial transcription factor A (TFAM)]. Electron microscopy of kidney tissues showed that mitochondrial damage was alleviated by treatment with an NRF2 agonist, and the opposite response occurred upon treatment with an NRF2 antagonist. Overall, our findings suggest that mitochondria have an important role in the pathogenesis of S-AKI, and that NRF2 activation restored mitochondrial homeostasis and function in the presence of this disease. This mitochondrial pathway has the potential to be a novel therapeutic target for the treatment of S-AKI.

Pinocembrin ameliorates lipopolysaccharide‑induced HK‑2 cell apoptosis and inflammation by regulating endoplasmic reticulum stress

Pinocembrin (PINO) is a natural flavonoid drug that possesses a range of biological activities, including antimicrobial, antioxidant and anti-inflammatory activities. The specific aim of the present study was to examine the pharmacological role of PINO in sepsis-mediated acute kidney injury (AKI), as well as to investigate the potential underlying mechanism. Human renal tubular epithelial cells (of the HK-2 cell line) were stimulated with lipopolysaccharide (LPS) for 24 h to simulate septic AKI in vitro, after which the experiments were repeated and the cells were pretreated with increasing concentrations of PINO (0, 50, 100 and 200 µg/ml). Using an MTT cell viability assay, PINO was revealed to be non-toxic to HK-2 cells. In LPS-treated HK-2 cells, PINO alleviated the loss of cell viability. Western blotting was used to analyze the expression levels of pro-inflammatory cytokines, including IL-1β, IL-6 and TNF-α, and the results revealed that PINO decreased the expression levels of these cytokines in a concentration-dependent manner. Furthermore, malondialdehyde (MDA) and glutathione (GSH) activities were assessed using MDA and GSH assay kits and it was revealed that PINO decreased the significantly increased level of malondialdehyde, while it also decreased the reduction in the level of GSH in LPS-challenged HK-2 cells. In addition, a TUNEL assay and western blotting were performed to examine cell apoptosis, and PINO was identified to significantly inhibit the level of apoptosis in LPS-induced HK-2 cells. Subsequently, the expression levels of endoplasmic reticulum stress (ERS)-associated factors, including activating transcription factor 4, C/EBP homologous protein and phosphorylated/total eukaryotic translation initiation factor 2 subunit 1 were examined by western blotting and it was demonstrated that ERS was triggered in HK-2 cells exposed to LPS, although this was partly circumvented through PINO treatment in a concentration-dependent manner. Furthermore, after the addition of tunicamycin, which acts as an agonist of ERS, the aforementioned experiments were performed again. Tunicamycin led to partial abolition of the protective function of PINO against inflammation, oxidative stress and apoptosis in LPS-challenged HK-2 cells. Overall, the results of the present study demonstrated that PINO was able to ameliorate the injuries sustained by LPS-challenged HK-2 cells via modulating ERS to reduce inflammation, oxidative stress and apoptosis; therefore, PINO may be a novel candidate drug for treating septic AKI.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Schisandra chinensis Oil Attenuates Aristolochic Acid I-Induced Nephrotoxicity in vivo and in vitro

OBJECTIVE

To investigate the protective effects of Schisandra chinensis oil (SCEO) against aristolochic acid I (AA I)-induced nephrotoxicity in vivo and in vitro and elucidate the underlying mechanism.

METHODS

C57BL/6 mice were randomly divided into 5 groups according to a random number table, including control group, AA I group, and AA I +SCEO (0.25, 0.5 and 1 g/kg) groups (n=5 per group). Pretreatment with SCEO was done for 2 days by oral administration, while the control and AA I groups were treated with sodium carboxymethyl cellulose. Mice of all groups except for the control group were injected intraperitoneally with AA I (5 mg/kg) from day 3 until day 7. Histopathological examination and apoptosis of kidney tissue were observed by hematoxylin and eosin and TdT-mediated dUTP nick-end labeling (TUNEL) staining, respectively. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and serum creatinine (SCr), as well as renal malondialdehyde (MDA), glutathione, r-glutamyl cysteingl+glycine (GSH), and superoxide dismutase (SOD) were analyzed using enzyme-linked immunosorbent assay (ELISA). Expressions of hepatic cytochrome P450 1A1 (CYP1A1), CYP1A2, and nad(p)hquinonedehydrogenase1 (NQO1) were analyzed using ELISA, quantitative real-time polymerase chain reaction (qPCR) and Western blot, respectively. In vitro, SCEO (40 µ g/mL) was added 12 h before treatment with AA I (40 µ mol/mL for 48 h) in human renal proximal tubule cell line (HK-2), then apoptosis and reactive oxygen species (ROS) were analyzed by flow cytometry.

RESULTS

SCEO 0.5 and 1 g/kg ameliorated histopathological changes and TUNEL⁺ staining in the kidney tissues of mice with AA I-induced nephrotoxicity, and reduced serum levels of ALT, AST, BUN and SCr (P<0.01 or P<0.05). SCEO 0.5 and 1 g/kg alleviated the ROS generation in kidney, containing MDA, GSH and SOD (P<0.01 or P<0.05). SCEO 1 g/kg increased the expressions of CYP1A1 and CYP1A2 and decreased NQO1 level in the liver tissues (P<0.01 or P<0.05). Besides, in vitro studies also demonstrated that SCEO 40 µ g/mL inhibited apoptosis and ROS generation (P<0.05 or P<0.01).

CONCLUSIONS

SCEO can alleviate AA I-induced kidney damage both in vivo and in vitro. The protective mechanism may be closely related to the regulation of metabolic enzymes, thereby inhibiting apoptosis and ROS production.

Oleic acid alleviates LPS-induced acute kidney injury by restraining inflammation and oxidative stress via the Ras/MAPKs/PPAR-γ signaling pathway

BACKGROUND

Rehmannia Glutinosa Libosch. is applied for the treatment of renal and inflammatory-related diseases, and oleic acid (OA) is a compound isolated from Rehmannia Glutinosa Libosch.. Unfortunately, the pharmacological activity of OA on LPS treated acute kidney injury (AKI) has not been investigated.

AIMS

The research is aiming to probe the activities of OA on LPS-induced AKI.

METHODS

Information of OA effect on AKI were from network pharmacology. H&E staining, creatinine (CRE) and urea nitrogen (UN) were performed to evaluate the activities of OA on kidney function. Inflammatory factors in serum were measured by cytometric bead array. Increased ratio of reactive oxygen species (ROS) in kidney and immune cells in the peripheral blood were determined by flow cytometry (FCM). PPAR-γ, MAPK and apoptotic signaling pathways were measured by Western blot. Then, a metabolomics approach was utilized to investigate OA's response to AKI. The role of salirasib (FTS, Ras inhibitor) in OA acted on ROS, Ca²⁺, MMP and Ras signaling pathway in LPS treated NRK-52e cells were investigated by FCM and In-cell western.

RESULTS

It is proved that OA effetively ameliorated renal function, alleviated inflammatory response and oxidative stress, and transformed apoptotic, MAPK and PPAR-γ signaling pathways in mice with AKI, regulated phenylalanine metabolism, purine metabolism, sphingolipid metabolism, taurine and hypotaurine metabolism, moreover, the role of OA in injury of NRK-52e was blocked by FTS.

CONCLUSION

In a word, OA could alleviate AKI by restraining inflammation and oxidative stress via regulating the Ras/MAPKs/PPAR-γ signaling pathway, phenylalanine metabolism, purine metabolism, sphingolipid metabolism and taurine and hypotaurine metabolism, which might be a useful strategy for treating AKI.

Bio-informatics and in Vitro Experiments Reveal the Mechanism of Schisandrin A Against MDA-MB-231 cells

Schisandrin A (SchA) has been reported to have good anti-cancer effects. However, its anti-cancer mechanism in breast cancer remains unknown. This study aimed to explore the mechanism of SchA in breast cancer treatment using bio-informatics analysis and in vitro experiments. The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Gene Cards, and PharmMapper databases were used to screen the candidate targets of SchA against MDA-MB-231 cells selected as the tested cell line through MTT analysis. The functions and pathways of the targets were identified using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and further analyzed using DAVID 6.8.1 database. Network pharmacology analysis revealed 77 candidate targets, 31 signal pathways, and 208 GO entries (P < 0.05). The targets regulated serine-type endopeptidase and protein tyrosine kinase activities, thereby promoting the migration and inhibiting the apoptosis of MDA-MB-231 cells. Comprehensive analysis of the ‘Protein–Protein Interaction’ (PPI) and ‘Component-Targets-Pathways’ (C-T-P) networks constructed using Cytoscape 3.7.1 software revealed four core targets: EGFR, PIK3R1, MMP9 and Caspase 3. Their docking scores with SchA were subsequently investigated through molecular docking. The wound healing, Hoechst 33342/PI, and western blot assays confirmed that SchA significantly down-regulated EGFR, PIK3R1, and MMP9, but up-regulated cleaved-caspase 3, thus inhibiting the migration and promoting the apoptosis of MDA-MB-231 cells. Reckoning the findings of the study, SchA is a potential adjuvant treatment for breast cancer.

Protection against acute renal injury by naturally occurring medicines which act through Nrf2 signaling pathway

The cellular defense pathway plays a key role in maintaining the homeostasis, tissues and organisms. Nuclear factor E2-related factor 2 (Nrf2), as a key cell signaling pathway, plays an important role in encoding detoxification enzymes and other stress response mediators. Recent studies have shown that it is closely related to the prevention and treatment of acute kidney injury (AKI). Therefore, this article reviews the protective effects of Nrf2-related signaling pathways on acute kidney injury, and summarizes the strategies of natural pharmaceutical ingredients such as flavonoids, alkaloids, terpenes, phenylpropionic acid, polyphenols, and polysaccharides to prevent and treat acute kidney injury. It is of great significance to further study the relationship between Nrf2 regulated signal pathway and kidney disease and the development of new medicines for acute kidney injury treatment. It can also provide new ideas and treatment strategies for clinical treatment of acute kidney injury. PRACTICAL APPLICATIONS: This article reviewed the mechanisms by which the active ingredients of natural medicines slow down acute kidney injury through the Nrf2 pathway. It will help us to understand the regulatory role of the Nrf2 pathway in AKI more comprehensively, and provide a theoretical basis for further exploring the mechanism of more natural drugs to reduce acute kidney injury.