Antioxidant effect of mogrosides against oxidative stress induced by palmitic acid in mouse insulinoma NIT-1 cells

Linoleyl acetate and mandenol alleviate HUA-induced ED via NLRP3 inflammasome and JAK2/STAT3 signalling conduction in rats

Hyperuricemia (HUA) is characterized by elevated blood uric acid levels, which can increase the risk of erectile dysfunction (ED). Clinical studies have demonstrated satisfactory efficacy of a traditional Chinese medicine formula QYHT decoction in improving ED. Furthermore, the main monomeric components of this formula, linoleyl acetate and mandenol, demonstrate promise in the treatment of ED. This study established an ED rat model induced by HUA and the animals were administered with linoleyl acetate and mandenol. HE and TUNEL were performed to detect tissue changes, ELISA to measure the levels of serum testosterone (T), MDA, NO, CRP, and TNF-α and qPCR and WB to assess the expression levels of NLRP3, ASC, Caspase-1, JAK2, and STAT3 in whole blood. The findings showed that linoleyl acetate and mandenol improved kidney tissue morphology, reduced cell apoptosis in penile tissue, significantly increased T and NO levels, while substantially decreasing levels of MDA, CRP, and TNF-α. Meanwhile, the expression of NLRP3, ASC, and Caspase-1 mRNAs and proteins was markedly reduced, and the phosphorylation of JAK2 and STAT3 was inhibited. These findings were further validated through faecal microbiota transplantation results. Taken together, linoleyl acetate and mandenol could inhibit NLRP3 inflammasome activation, reduce inflammatory and oxidative stress responses, suppress the activity of JAK-STAT signalling pathway, ultimately providing a potential treatment for HUA-induced ED.

Glucotoxicity is mediated by cytoplasmic distribution of RAP1 in pancreatic β-cells

Diabetes mellitus (DM) is a group of chronic metabolic disorders characterized by persistent hyperglycemia. In our study, we analyzed the level and location of RAP1 changes in the development of β-cell dysfunction induced by glucotoxicity. We employed three pancreatic β-cell lines, namely INS-1, 1.2B4, and NIT-1, as well as a streptozotocin-induced diabetes rat model. We demonstrate that after high glucose treatment, RAP1 is increased, probably through induction by AKT, allowing RAP1 to shuttle from the nucleus to the cytoplasm and activate NF-κB signaling. Furthermore, non-enzymatic post-translational modifications of RAP1, such as advanced glycation end products and carbonylation may affect the function of RAP1, such as activation of the NF-κB signaling. Taken together, we showed that RAP1 is a new player in the mechanism of glucotoxicity in pancreatic β-cells.

The Counteracting Effects of Ang II and Ang-(1-7) on the Function andGrowth of Insulin-secreting NIT-1 Cells

INTRODUCTION

China now has the highest number of diabetes in the world. Angiotensin II (Ang II) causes insulin resistance by acting on the insulin signaling pathway of peripheral target tissues. However, its effect on islet β-cells remains unclear. The possible role of Angiotensin-( 1-7) [Ang-(1-7)] as an antagonist to the effects of Ang II and in treating diabetes needs to be elucidated.

OBJECTIVES

To assess the effects of Ang II and Ang-(1-7) on the function and growth of islet β cell line NIT-1, which is derived from the islets of non-obese diabetic/large T-antigen (NOD/LT) mice with insulinoma.

METHODS

NIT-1 cells were treated with Ang II, Ang-(1-7) and their respective receptor antagonists. The impact on cell function and growth was then evaluated.

RESULTS

Ang II significantly reduced insulin-stimulated IR-β-Tyr and Akt-Ser; while Ang-(1-7), saralasin (an Ang II receptor antagonist), and diphenyleneiodonium [DPI, a nicotinamide adenine dinucleotide phosphate oxidase (NOX) antagonist] reversed the inhibiting effect. Conversely, Ang II significantly increased insulin-stimulated intracellular H2O2 and P47 phox, while saralasin and DPI reverted the effect. Furthermore, Ang-(1-7) reduced the elevated concentrations of ROS and MDA while increasing the proliferation rate that was reduced by high glucose, all of which were reversed by A-779, an antagonist of the Mas receptor (MasR).

CONCLUSION

Angiotensin II poses a negative regulatory effect on insulin signal transduction, increases oxidative stress, and may inhibit the transcription of insulin genes stimulated by insulin in NIT-1 cells. Meanwhile, angiotensin-(1-7) blocked these effects via MasR. These results corroborate the rising potential of the renin-angiotensin system (RAS) in treating diabetes.

Perinatal stress exposure induced oxidative stress, metabolism disorder, and reduced GLUT-2 in adult offspring of rats

PURPOSE

Growing evidence has demonstrated that adversity in early life, especially in the prenatal and postnatal period, may change the programming of numerous body systems and cause the incidence of various disorders in later life. Accordingly, this experimental animal study aimed to investigate the effect of stress exposure during perinatal (prenatal and/or postnatal) on the induction of oxidative stress in the pancreas and its effect on glucose metabolism in adult rat offspring.

METHODS

In this experimental study based on maternal exposure to variable stress throughout the perinatal period, the pups were divided into eight groups, as follows: control group (C); prepregnancy, pregnancy, lactation stress group (PPPLS); prepregnancy stress group (PPS); pregnancy stress group (PS); lactation stress group (LS); prepregnancy, pregnancy stress group (PPPS); pregnancy, lactation stress group (PLS); and prepregnancy, lactation stress group (PPLS). Following an overnight fast on postnatal day (PND) 64, plasma glucose, insulin, leptin levels, and lipid profiles were evaluated in the offspring groups. GLUT-2 protein levels, lipid peroxidation, antioxidant status, and number of beta-cells in the pancreatic islets of Langerhans as well as the weights of intra-abdominal fat and adrenal glands were assessed. Levels of plasma corticosterone were determined in the different groups of mothers and offspring.

RESULTS

The levels of plasma corticosterone, insulin, and HOMA-B index increased, whereas glucose level and QUICKI index were reduced in the perinatal stress groups compared to C group (p < 0.001 to p < 0.05). Plasma triglyceride, LDL, and cholesterol level rose significantly, but HDL level decreased in the perinatal stress groups compared to C group (p < 0.001 to p < 0.05). Perinatal stress raised MDA concentrations and reduced the activities of antioxidant enzymes in plasma and pancreas compared to C group (p < 0.001 to p < 0.05). GLUT-2 protein levels and number of beta-cells in the stress groups declined compared to C group (p < 0.001 to p < 0.05). Intra-abdominal fat weight decreased in the PPS, PS, and LS groups compared to C group (p < 0.001 to p < 0.01), but adrenal gland weight remained unchanged.

CONCLUSION

Our results showed that long-term exposure to elevated levels of corticosterone during critical development induces metabolic syndrome in adult male rats.

Guanmaitong Granule Attenuates Atherosclerosis by Inhibiting Inflammatory Immune Response in ApoE−/− Mice Fed High-Fat Diet

Background

Atherosclerosis (AS) is the leading cause of cardiovascular diseases, such as myocardial infarction and stroke. Guanmaitong granule (GMTG) is a TCM (Traditional Chinese medicine) prescribed to treat AS. However, its mechanism remains unclear.

Methods

We obtained reliable ingredients and targets of GMTG using the HERB database. AS-related targets were obtained from HERB and GeneCards databases. The target database was constructed by intersecting the ingredients of GMTG with the AS-related targets. STRING and Cytoscape were used to create protein-protein interaction (PPI) network and screen core targets. GO enrichment analysis and KEGG pathway analyses were performed using R. Finally, the ApoE^−/− mice AS model was induced by a high-fat diet (HFD) for in vivo validation of core pathways and targets.

Results

A total of 124 ingredients and 418 potential targets of GMTG for treating AS were obtained. Numerous ingredients and targets were related to Panax notoginseng, Salvia miltiorrhiza, and Astragalus. Most core targets and pathways were involved in the inflammatory immune response. GMTG could decrease serum triglycerides, total cholesterol, low-density lipoprotein-cholesterol, and oxidized low-density lipoprotein level and increase the serum high-density lipoprotein-cholesterol level. Furthermore, GMTG reduced the plaque burden and promoted plaque remodeling by reducing plaque area, lipid deposition, foam cell content, and collagen fiber content in the plaque in the aortic root of ApoE^−/− mice. GMTG inhibited systemic and plaque inflammatory immune response and increased plaque stability by inhibiting the excessive release of the TLR4/MyD88/NF-κB pathway-induced inflammatory cytokines, tumor necrosis factor, interleukin-6, and interleukin-1 beta.

Conclusion

Radix notoginseng, Radix salviae liguliobae, and Radix astragali are the main ingredients of GMTG for treating AS. Further, GMTG could regulate the level of serum lipids and inhibit inflammatory immune response, which resulted in anti-AS effects such as plaque stabilization, reduction of plaque burden, and plaque remodeling. GMTG is a promising multi-target treatment for AS.

Investigation of pathogenesis of hyperuricemia based on untargeted and targeted metabolomics

Hyperuricemia (HUA) seriously harms human health but the exact etiology and pathogenesis of HUA are not fully understood. Therefore, it is still of great significance to find effective biomarkers and explore the pathogenesis of HUA. Metabolomics reflects the influence of internal and external factors on system metabolism, explains the changes in metabolite levels during the development of diseases, and reveals the molecular mechanism of pathogenesis. Metabolomics is divided into untargeted metabolomics and targeted metabolomics according to different research modes. Each other's advantages can be fully utilized by combining the two so that the results of metabolomics research can be consummated. 20 HUA patients and 20 healthy individuals participated in the experiment, and untargeted metabolomics was employed to find 50 differential metabolites in HUA serum samples. Twelve candidate biomarkers were screened based on literature research and ROC Curve analysis for subsequent verification. Based on the UPLC-TQ-MS analysis platform, the targeted metabolomics detection methods were established and the content of 12 candidate biomarkers was precisely quantified. Compare with the results of untargeted metabolomics, the targeted metabolomics results were considered more reliable.

A Novel Herbal Extract Blend Product Prevents Particulate Matters-Induced Inflammation by Improving Gut Microbiota and Maintaining the Integrity of the Intestinal Barrier

Air pollutants of PM2.5 can alter the composition of gut microbiota and lead to inflammation in the lung and gastrointestinal tract. The aim of this study was to evaluate the protective effect of a novel herbal extract blend, FC, composed of Lonicera japonica extract, Momordica grosvenori extract, and broccoli seed extract, on PM2.5-induced inflammation in the respiratory and intestinal tract. A549 cells and THP-1 cells, as well as C57BL/6 mice, were stimulated with PM2.5 to establish in vitro and in vivo exposure models. The models were treated with or without FC. The expression of inflammatory cytokines and tight junction proteins were studied. Proteomic analysis was performed to elucidate mechanisms. Mouse feces were collected for gut microbiota analysis. FC was shown to modulate the upregulation of pro-inflammatory cytokines mRNA expression in A549 and THP-1 cells and downregulated tight junction proteins mRNA expression in A549 cells due to PM2.5 stimulation. In animal models, the decreased expression of the anti-inflammatory factor il-10, tight junction protein ZO-1, and the elevated expression of COX-2 induced by PM2.5 were improved by FC intervention, which may be associated with zo-1 and cox-2 signaling pathways. In addition, FC was shown to improve the gut microbiota by increasing the abundance of beneficial bacteria.

Protective Effects of Mogroside V on Oxidative Stress Induced by H2O2 in Skin Fibroblasts

Purpose

Damage caused by oxidative stress leads to the premature aging of cells. Mogrosides, the main active components of Siraitia grosvenorii, have strong antioxidant activity; however, it is unclear whether mogroside V (MV) exerts these effects in skin cells. This was investigated in the present study by evaluating the protective effects of MV against oxidative damage induced by hydrogen peroxide (H₂O₂) in skin fibroblasts.

Methods

Mouse skin fibroblasts (MSFs) were treated with H₂O₂ and cell viability, total antioxidant capacity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and antioxidant enzyme activity were assessed.

Results

Treatment with MV reduced the ROS level and MDA content in MSFs treated with H₂O₂. This was accompanied by increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities.

Conclusion

MV reduces H₂O₂-induced oxidative stress and enhances endogenous antioxidant activity in skin fibroblasts. Thus, MV can potentially be used as an ingredient in anti-aging cosmetic products.

Food-derived cyanidin-3-O-glucoside alleviates oxidative stress: evidence from the islet cell line and diabetic db/db mice

Type 2 diabetes mellitus is a disease associated with an oxidative milieu that often leads to adverse health outcomes. Multiple anthocyanins have been reported to possess outstanding antioxidant activity, however, their effects on hyperglycemia-related oxidative stress remain elusive. In the present study, cyanidin-3-O-glucoside (C3G), a typical anthocyanin with various widely accepted health benefits, was applied to alleviate oxidative stress in pancreas islets under the conditions of hyperglycemia. Firstly, significantly decreased mitochondrial membrane potential (MMP) and antioxidant enzymes, as well as increased reactive oxygen species (ROS) and O₂^- levels, were detected after exposure to a series of concentrations of high glucose (HG) and palmitic acid (PA), which manifested oxidative stress triggered by mitochondrial damage. To evaluate the antioxidant effect of C3G in vitro, the islet cell line NIT-1 was used, and results proved that C3G could effectively relieve cellular oxidative stress induced by HG and PA. Furthermore, we found that the antioxidant effect of C3G was achieved by activating mitophagy via the PINK1-PARKIN signaling pathway. More importantly, an autophagy inhibitor chloroquine (CQ) was added to verify our findings at the protein level, and we observed the co-localization of mitochondria and lysosomes, which may form autophagolysosomes to clean damaged mitochondria. Immediately afterwards, more studies were conducted on pancreatic islets of diabetic db/db mice to verify the antioxidant effect of C3G discovered in islet cells. Along with the decline in fasting blood glucose, the oxidative stress in pancreas islets was successfully alleviated in diabetic db/db mice after supplementation with C3G. This was demonstrated by increased levels of ROS, and the impaired activities of anti-oxidative enzymes superoxide dismutase (SOD) and catalase (CAT) were partly reversed by C3G intervention. Our study has provided evidence for the alleviation effect of C3G against oxidative stress in pancreas islets, which may provide enlightenment for improving the health situation of diabetic patients in the future.

Molecular Mechanisms of Apoptosis Induction and Its Regulation by Fatty Acids in Pancreatic β-Cells

Pancreatic β-cell failure and death contribute significantly to the pathogenesis of type 2 diabetes. One of the main factors responsible for β-cell dysfunction and subsequent cell death is chronic exposure to increased concentrations of FAs (fatty acids). The effect of FAs seems to depend particularly on the degree of their saturation. Saturated FAs induce apoptosis in pancreatic β-cells, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction by saturated FAs in β-cells are not completely elucidated. Saturated FAs induce ER stress, which in turn leads to activation of all ER stress pathways. When ER stress is severe or prolonged, apoptosis is induced. The main mediator seems to be the CHOP transcription factor. Via regulation of expression/activity of pro- and anti-apoptotic Bcl-2 family members, and potentially also through the increase in ROS production, CHOP switches on the mitochondrial pathway of apoptosis induction. ER stress signalling also possibly leads to autophagy signalling, which may activate caspase-8. Saturated FAs activate or inhibit various signalling pathways, i.e., p38 MAPK signalling, ERK signalling, ceramide signalling, Akt signalling and PKCδ signalling. This may lead to the activation of the mitochondrial pathway of apoptosis, as well. Particularly, the inhibition of the pro-survival Akt signalling seems to play an important role. This inhibition may be mediated by multiple pathways (e.g., ER stress signalling, PKCδ and ceramide) and could also consequence in autophagy signalling. Experimental evidence indicates the involvement of certain miRNAs in mechanisms of FA-induced β-cell apoptosis, as well. In the rather rare situations when unsaturated FAs are also shown to be pro-apoptotic, the mechanisms mediating this effect in β-cells seem to be the same as for saturated FAs. To conclude, FA-induced apoptosis rather appears to be preceded by complex cross talks of multiple signalling pathways. Some of these pathways may be regulated by decreased membrane fluidity due to saturated FA incorporation. Few data are available concerning molecular mechanisms mediating the protective effect of unsaturated FAs on the effect of saturated FAs. It seems that the main possible mechanism represents a rather inhibitory intervention into saturated FA-induced pro-apoptotic signalling than activation of some pro-survival signalling pathway(s) or metabolic interference in β-cells. This inhibitory intervention may be due to an increase of membrane fluidity.

Integrated metabolomics and network toxicology to reveal molecular mechanism of celastrol induced cardiotoxicity

Celastrol (CS), an active triterpene derived from traditional Chinese medicine Tripterygium wilfordii Hook. f, has been used to treat chronic inflammation, arthritis and other diseases. However, it has been reported that CS can trigger cardiotoxicity and the molecular mechanism of heart injury induced by CS is not clear. Considering the wide application of Tripterygium wilfordii Hook. f in clinics, it is necessary to develop an accurate and reliable method to assess the safety of CS, and to elucidate as much as possible the mechanism of cardiotoxicity induced by CS. In this study, Ultra-performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF/MS)-based metabolomics revealed clues to the mechanism of CS-induced heart injury. Palmitic acid significantly increased in plasma from CS-treated rats, and this increase resulted in oxidative stress response in vivo. Excessive ROS further activate TNF signaling pathway and caspase family, which were obtained from the KEGG enrichment analysis of network toxicology strategy. Protein expression level of caspase-3, caspase-8, bax were significantly increased by western blot. Q-PCR also showed the similar results as western blot. It means that apoptosis plays a key role in the process of celastrol induced cardiotoxicity. Blocking this signal axis may be a potential way to protect myocardial tissue.

Berberine attenuates sodium palmitate-induced lipid accumulation, oxidative stress and apoptosis in grass carp(Ctenopharyngodon idella)hepatocyte in vitro

The objective of this work was to investigate the effect of berberine (BBR) on the Cell viability, lipid accumulation, apoptosis, cytochrome c, caspase-9 and caspase-3 in lipid accumulation-hepatocytes induced by sodium palmitate in vitro. The lipid accumulation-hepatocytes (induced by 0.5 mM sodium palmitate for 24 h) were treated with 5 μM berberine for 12 h. Then, the Cell viability, intracellular triglyceride (TG) content, lipid peroxide (LPO), malonaldehyde (MDA) content, cytochrome c, caspase-9, caspase-3 and apoptosis were detected. Sodium palmitate decreased Cell viability and increased intracellular TG content, lipid droplet accumulation, LPO and MDA concentrations, caused caspase-3 and caspase-9 activation, then led to apoptosis accompanied by cytochrome c release from mitochondria into the cytoplasm. Beberine could improve intracellular lipid droplet accumulation and oxidative stress, while reduce apoptosis induced by sodium palmitate.

Inhibition of Receptor Interacting Protein Kinases Attenuates Cardiomyocyte Hypertrophy Induced by Palmitic Acid

Palmitic acid (PA) is known to cause cardiomyocyte dysfunction. Cardiac hypertrophy is one of the important pathological features of PA-induced lipotoxicity, but the mechanism by which PA induces cardiomyocyte hypertrophy is still unclear. Therefore, our study was to test whether necroptosis, a receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3-) dependent programmed necrosis, was involved in the PA-induced cardiomyocyte hypertrophy. We used the PA-treated primary neonatal rat cardiac myocytes (NCMs) or H9c2 cells to study lipotoxicity. Our results demonstrated that cardiomyocyte hypertrophy was induced by PA treatment, determined by upregulation of hypertrophic marker genes and cell surface area enlargement. Upon PA treatment, the expression of RIPK1 and RIPK3 was increased. Pretreatment with the RIPK1 inhibitor necrostatin-1 (Nec-1), the PA-induced cardiomyocyte hypertrophy, was attenuated. Knockdown of RIPK1 or RIPK3 by siRNA suppressed the PA-induced myocardial hypertrophy. Moreover, a crosstalk between necroptosis and endoplasmic reticulum (ER) stress was observed in PA-treated cardiomyocytes. Inhibition of RIPK1 with Nec-1, phosphorylation level of AKT (Ser473), and mTOR (Ser2481) was significantly reduced in PA-treated cardiomyocytes. In conclusion, RIPKs-dependent necroptosis might be crucial in PA-induced myocardial hypertrophy. Activation of mTOR may mediate the effect of necroptosis in cardiomyocyte hypertrophy induced by PA.

Fenugreek lactone attenuates palmitate-induced apoptosis and dysfunction in pancreatic β-cells

AIM

To investigate the effect of fenugreek lactone (FL) on palmitate (PA)-induced apoptosis and dysfunction in insulin secretion in pancreatic NIT-1 β-cells.

METHODS

Cells were cultured in the presence or absence of FL and PA (0.25 mmol/L) for 48 h. Then, lipid droplets in NIT-1 cells were observed by oil red O staining, and the intracellular triglyceride content was measured by colorimetric assay. The insulin content in the supernatant was determined using an insulin radio-immunoassay. Oxidative stress-associated parameters, including total superoxide dismutase, glutathione peroxidase and catalase activity and malondialdehyde levels in the suspensions were also examined. The expression of upstream regulators of oxidative stress, such as protein kinase C-α (PKC-α), phospho-PKC-α and P47phox, were determined by Western blot analysis and real-time PCR. In addition, apoptosis was evaluated in NIT-1 cells by flow cytometry assays and caspase-3 viability assays.

RESULTS

Our results indicated that compared to the control group, PA induced an increase in lipid accumulation and apoptosis and a decrease in insulin secretion in NIT-1 cells. Oxidative stress in NIT-1 cells was activated after 48 h of exposure to PA. However, FL reversed the above changes. These effects were accompanied by the inhibition of PKC-α, phospho-PKC-α and P47phox expression and the activation of caspase-3.

CONCLUSION

FL attenuates PA-induced apoptosis and insulin secretion dysfunction in NIT-1 pancreatic β-cells. The mechanism for this action may be associated with improvements in levels of oxidative stress.

Fenugreek lactone attenuates palmitate-induced apoptosis and dysfunction in pancreatic β-cells

AIM

To investigate the effect of fenugreek lactone (FL) on palmitate (PA)-induced apoptosis and dysfunction in insulin secretion in pancreatic NIT-1 β-cells.

METHODS

Cells were cultured in the presence or absence of FL and PA (0.25 mmol/L) for 48 h. Then, lipid droplets in NIT-1 cells were observed by oil red O staining, and the intracellular triglyceride content was measured by colorimetric assay. The insulin content in the supernatant was determined using an insulin radio-immunoassay. Oxidative stress-associated parameters, including total superoxide dismutase, glutathione peroxidase and catalase activity and malondialdehyde levels in the suspensions were also examined. The expression of upstream regulators of oxidative stress, such as protein kinase C-α (PKC-α), phospho-PKC-α and P47phox, were determined by Western blot analysis and real-time PCR. In addition, apoptosis was evaluated in NIT-1 cells by flow cytometry assays and caspase-3 viability assays.

RESULTS

Our results indicated that compared to the control group, PA induced an increase in lipid accumulation and apoptosis and a decrease in insulin secretion in NIT-1 cells. Oxidative stress in NIT-1 cells was activated after 48 h of exposure to PA. However, FL reversed the above changes. These effects were accompanied by the inhibition of PKC-α, phospho-PKC-α and P47phox expression and the activation of caspase-3.

CONCLUSION

FL attenuates PA-induced apoptosis and insulin secretion dysfunction in NIT-1 pancreatic β-cells. The mechanism for this action may be associated with improvements in levels of oxidative stress.