Dimethyl fumarate ameliorates acetaminophen-induced hepatic injury in mice dependent of Nrf-2/HO-1 pathway

Mof plays distinct roles in hepatic lipid metabolism under healthy or non-alcoholic fatty liver conditions

The disturbance of hepatic lipid metabolism has a strong association with non-alcoholic fatty liver disease (NAFLD) and diabetes. Mof, an acetyltransferase involved in obesity and carbon metabolism, has not been thoroughly examined in its connection to hepatic metabolism. We aimed to explore the impact of Mof on hepatic lipid metabolism. The alteration of Mof expression was found in both obese mice and NAFLD human liver. The genes regulated by Mof were closely associated with lipid metabolism. In normal mice or hepatic cells, the down-regulation or inhibition of Mof resulted in increased lipid accumulation due to decreased PPARα expression. Conversely, in diet-induced obesity (DIO) mice or hepatic cells treated with palmitic acid, the inhibition of Mof led to improved lipid metabolism, attributed to the reduction in p-mTOR/mTOR levels. In summary, Mof exhibited distinct roles in lipid metabolism under different conditions. The inhibition of Mof may hold potential as a therapeutic target for hepatic lipid metabolism disturbances.

Simultaneous intervention against oxidative stress and inflammation by targeting Nrf2/ARE and NLRP3 inflammasome pathway mitigates thioacetamide-induced liver fibrosis in rat

Liver fibrosis is a typical pathological state/stage involved in most chronic liver diseases and its persistence results in cirrhosis. Inflammasomes are cytoplasmic sensors that induce inflammation in response to stress. Glibenclamide (GLB) is an USFDA-approved drug for type 2 diabetes and is reported to possess anti-inflammatory activity by inhibiting inflammatory cytokines. Dimethyl fumarate (DMF) is an USFDA-approved drug for multiple sclerosis and has been reported to activate the Nrf2/ARE pathway to maintain the cellular antioxidant balance. A total of 36 rats were randomized into six groups (n = 6 each). The rats were injected with thioacetamide (TAA) 200 mg/kg, intraperitoneally every third day for eight consecutive weeks to induce liver fibrosis and oral treatment of GLB 0.5 mg/kg/day and DMF 25 mg/kg/day, and their combinations were provided for the last four consecutive weeks. Treatment with GLB, DMF, and GLB+DMF significantly protected against TAA-mediated oxidative stress and inflammatory conditions by improving hepatic function test, triglycerides, hydroxyproline, and histopathological alterations, by inhibiting the NLRP3 inflammasome signaling and fibrogenic markers, and by activating Nrf2/ARE pathway in Wistar rats. The present results suggest that simultaneous Nrf2/ARE activation and NLRP3 inflammasome inhibition could significantly contribute to developing a novel therapy for patients with liver fibrosis.

Novel Gastroprotective and Thermostable Cocrystal of Dimethyl Fumarate: Its Preparation, Characterization, and In Vitro and In Vivo Evaluation

Crystallization has revolutionized the field of solid-state formulations by modulating the physiochemical and release profile of active pharmaceutical ingredients (APIs). Dimethyl fumarate (DF), an FDA-approved first-line drug for relapsing-remitting multiple sclerosis, has a sublimation problem, leading to loss of the drug during its processing. To tackle this problem, DF cocrystal has been prepared by using solvent evaporation technique using nicotinamide as a coformer, which has been chosen based on in silico predictions and their ability to participate in hydrogen bonding. Fourier transform infrared (FT-IR), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and sublimation analysis have characterized the cocrystal and its thermostability. Comparative analysis of the release profile has been done by the dissolution and pharmacokinetic study of DF and its cocrystal. Formulated cocrystal is noncytotoxic, antioxidant and inhibits interleukin-6 and tissue necrosis factor-α in peripheral blood mononuclear cells induced by lipopolysaccharide. We have obtained a thermostable cocrystal of DF with a similar physicochemical and release profile to that of DF. The formulated cocrystal also provides a gastroprotective effect which helps counterbalance the adverse effects of DF by reducing lipid peroxidation and total nitrite levels.

Psoriatic disease and non-alcoholic fatty liver disease shared pathogenesis review

Psoriatic disease (PD) and non-alcoholic fatty liver disease (NAFLD) potentially share disease pathways given the numerous inflammatory pathways involved in both diseases and a higher prevalence of NAFLD in PD patients.  Metabolic syndrome and obesity are a key link between the two diseases, but even when controlling for this, associations between both diseases are still seen. Therapeutics that impact metabolic or inflammatory pathways may be impactful in both PD and NAFLD. In this review, we describe common inflammatory pathways contributing to both PD and NAFLD and critically review the potential impact of treatments for and on both diseases.

Down-regulation of connexin 43 contributes to structure and function of pulmonary artery in nicotine-administered mice

Dysregulated connexin signaling is implicated in the pathophysiology of pulmonary artery hypertension (PAH). Nicotine affects pulmonary vascular remodeling. However, the potential mechanistic link between connexin signaling and nicotine-induced pulmonary artery remodeling remains unclear. We aimed to investigate the role of connexin 43 (Cx43) in pulmonary artery remodeling in nicotine-administered C57BL/6 J wild-type (WT) and Cx43 heterozygous (Cx43^+/-) mice. Hemodynamic parameters and right ventricle pathology were assessed in the mice. Serum biochemical indices of hepatic and renal function were measured. The RT-PCR, immunofluorescence, and western blotting were conducted to evaluate Cx43 mRNA and protein levels. We performed histological staining to identify pulmonary arteries. Wire myography was used to examine contraction and relaxation responses in the pulmonary arteries. Pulmonary vascular permeability was assessed through Evans blue staining. Compared with the WT group, the Cx43^+/- group showed lower Cx43 mRNA and protein expression in the pulmonary arteries (P < 0.01). Nicotine treatment significantly increased Cx43 expression (P < 0.01) and induced morphological changes in the pulmonary arteries (P < 0.01). Our findings suggest that Cx43 plays a crucial role in pulmonary artery reactivity and permeability in mice. Furthermore, downregulation of Cx43 expression may contribute to alterations in pulmonary artery structure and function.

Piperine mitigates aortic vasculopathy in streptozotocin-diabetic rats via targeting TXNIP-NLRP3 signaling

Several in vivo and in vitro studies reported a favorable effect of piperine (PIP) on vascular function. However, the potential impacts of PIP on macrovasculopathy in streptozotocin (STZ)-diabetic rats have not yet been studied. Thirty-two Sprague Dawley rats were used (n= 8/group). STZ-administered rats (50 mg/kg once, i.p) received PIP (30 mg/kg/day, orally) or its vehicle starting from day 15 till the end of the study (10 weeks). Control groups consisted of age-matched normal rats with or without PIP treatment. Metabolic and oxidative stress parameters were biochemically determined. Aortas were histologically examined. Ex vivo aortic reactivity to phenylephrine and acetylcholine was studied. Components of the TXNIP-NLRP3 pathway were assessed using real-time PCR, ELISA, and immunohistochemistry. Two-way ANOVA was used to compare groups. Statistical significance was set at P < 0.05. PIP treatment of diabetic rats significantly reduced levels of fasting glycemia, HbA_1c, and serum AGEs, TGs, TC, and LDL-C compared to control diabetic group. PIP diminished aortic endothelial denudation and fibrous tissue proliferation compared to control STZ aortas. PIP lessened aortic contractility to phenylephrine and improved aortic relaxation to acetylcholine relative to untreated STZ group. PIP administration to diabetic rats elicited significant enhancements in GSH and SOD levels, eNOS expression, and total nitrate/nitrite bioavailability compared to untreated STZ rats. Moreover, PIP attenuated aortic contents of ROS, MDA, TXNIP protein and mRNA, NF-κB p65 mRNA, NLRP3 mRNA, IL-1β protein, and caspase-3 and TNF-α expressions compared to untreated STZ levels. In conclusion, PIP might ameliorate diabetes-associated functional and structural aortic remodeling by targeting TXNIP-NLRP3 signaling.

Hepatoprotective effect of nicorandil against acetaminophen-induced oxidative stress and hepatotoxicity in mice via modulating NO synthesis

Acetaminophen (APAP) overdose can produce hepatotoxicity and consequently liver damage. This study investigated the hepatoprotective impacts of nicorandil on hepatic damage induced by APAP. Nicorandil was administered orally (100 mg/kg) for seven days before APAP challenge (500 mg/kg, ip). Pretreatment with nicorandil reduced serum levels of aminotransferases, bilirubin, GGT and LDH, and increased serum level of albumin. Moreover, nicorandil inhibited the increase in liver MDA levels and reversed the decline in GSH content and SOD activity. Besides, it notably alleviated APAP-induced necrosis observed in histopathological findings. Additionally, nicorandil alleviated APAP-induced NO overproduction and iNOS expression; however, the protein expression of eNOS was significantly increased. Moreover, nicorandil markedly reduced hepatic TNF-α and NF-κB levels, in addition to decreasing the protein expression of MPO in hepatic tissues. Furthermore, flow cytometry (annexin V-FITC/PI) displayed a significant decline in late apoptotic and necrotic cells, and an increase in viable cells in nicorandil group. Also, nicorandil caused a significant boost in hepatic antiapoptotic marker bcl-2 level. The presented data proposed that the protective effect of nicorandil might be attributed to its antioxidant, its impact on NO homeostasis, and its anti-inflammatory properties. Therefore, nicorandil may be a promising candidate for protection from liver injury induced by APAP.

Cardamom Extract Alleviates the Oxidative Stress, Inflammation and Apoptosis Induced during Acetaminophen-Induced Hepatic Toxicity via Modulating Nrf2/HO-1/NQO-1 Pathway

Acetaminophen (APAP) is the most extensively used and safest analgesic and antipyretic drug worldwide; however, its toxicity is associated with life-threatening acute liver failure. Cardamom (CARD), a sweet, aromatic, commonly used spice, has several pharmacological actions. In the current study, we tried to explore the chemical composition and the hepato-protective effect of ethanolic aqueous extract of CARD to mitigate APAP-induced hepatic toxicity and elucidate its underlying mechanism of action. Material and methods: Aqueous CARD extract was subjected to LC-TOF-MS analysis to separate and elucidate some of its components. In vivo animal experiments involved five groups of animals. In the normal and cardamom groups, mice were administered either saline or CARD (200 mg/kg), respectively, orally daily for 16 days. In the APAP group, the animals were administered saline orally daily for 15 days, and on the 16th day, animals were administered APAP (300 mg/kg) IP for the induction of acute hepatic failure. In the CARD 200 + APAP group, mice were administered CARD (200 mg/kg) for 15 days, followed by APAP on the 16th day. Results: The aqueous extract of CARD showed several compounds, belonging to polyphenol, flavonoids, cinnamic acid derivatives and essential oil components. In the in vivo investigations, APAP-induced impaired liver function, several histopathological alterations, oxidative stress and inflammatory and apoptotic status signified severe hepatic failure. Whereas, pretreatment with the CARD extract prior to APAP administration diminished serum levels of the hepatic function test and augmented Nrf2 nucleoprotein and HO-1 and NQO-1. CARD down-regulated MDA, inflammatory mediators (IL-1β, IL-6, TNF-α and NF-κB) and apoptotic markers (caspase 3 and 9 and Bax) and amplified the activities of SOD, catalase, GSH-Px and GSH-R in hepatic tissue samples. Conclusion: CARD extract mitigated the hepatic toxicity induced by APAP. The underlying mechanism of action of such hepato-protective action may be through upregulation of the Nrf2/HO-1/NQO-1 pathway with subsequent alleviation of the oxidative stress, inflammation and apoptosis induced by APAP. Many of the compounds identified in the CARD extract could be attributed to this pharmacological action of the extract.

The emerging coloprotective effect of sildenafil against ulcerative colitis in rats via exerting counterbalance between NF-κB signaling and Nrf-2/HO-1 pathway

The current work explored the influences of time dependent Sildenafil (SILD) administration, and the possible outcomes from its concomitant administration with dexamethasone against acetic acid-induced ulcerative colitis in rats. Rats were assigned into six random groups: diseased group (AA), injected once with 2 ml acetic acid (3%) intrarectally, 2 days before sacrification. SILD + AA, received sildenafil (25 mg/kg, orally) for 6 days starting 3 days pre-injection of AA; SILD-t + AA, received sildenafil (25 mg/kg, orally), starting at time of AA injection and continued for 3 days; DEXA + AA, received dexamethasone (2 mg/kg, i.p.) for 3 days, starting at time of AA injection; SILD-t + DEXA + AA, received sildenafil (25 mg/kg, orally) and dexamethasone (2 mg/kg, i.p.), as mentioned. Sildenafil markedly ameliorated disease activity index (DAI), ulcer scores, colon length shortening and colonic histopathological changes. Mechanistically, Sildenafil markedly attenuated immunoexpression of NF-κB p65/ TNF-α and COX-2, diminished oxidative stress (↓ MDA/NO levels and ↑ GSH level and SOD activity), increased levels of Nrf-2/HO-1, compared to untreated group. Taken together, Sildenafil treatment suppressed acetic acid-induced ulcerative colitis, probably via inhibiting NF-κB/TNF-α signaling dependent of Nrf-2/HO-1 pathway, reducing oxidative stress and attenuating inflammation. Surprisingly, effects of sildenafil were unpromoted in a time dependant manner. Short term treatment with sildenafil was sufficient to exert its coloprotective effect, while longer term pretreatment was only superior among other treatments in the macroscopical changes. Moreover, concurrent administration of sildenafil and dexamethasone had the preference in boosting the antioxidant defense and anti-inflammatory mechanisms, visualized by histopathological/immunohistochemical changes.

Beneficial effect of trimetazidine on folic acid-induced acute kidney injury in mice: Role of HIF-1α/HO-1

Acute kidney injury (AKI) is a complex syndrome associated with a decrease in renal function and a significant impact on patient outcomes. Injection of folic acid (FA) in mice is used for studying the pathogenesis of AKI. This study investigated the impact of trimetazidine (a metabolic modulator-antianginal drug; TMZ), against FA-induced AKI. AKI was induced by FA (250 mg/kg, ip) in mice. Two doses of TMZ were administered orally for 10 days. Administration of TMZ at a high dose (20 mg/kg) exhibited significant decreases in the renal somatic index (RSI), serum levels of lactate dehydrogenase (LDH), creatinine (Cr), blood urea nitrogen (1), and proteins level in urine. Moreover, TMZ significantly increased creatinine clearance (CCr), serum albumin, urine creatinine, and urine urea levels. This improvement in markers of kidney damage was associated with marked renal antioxidant effects (↓NO and ↓lipid peroxidation, normalized reduced glutathione (GSH) level and superoxide dismutase (SOD) activity, and increased HIF-1α/HO-1 level). Furthermore, TMZ significantly decreased FA-induced expression of MPO and inflammatory cytokine IL-18, TNF-α, and NF-κB p65 subunit. Renal apoptosis, along with apoptotic markers, were enhanced by FA injection and suppressed by TMZ administration (↓Caspase-3, ↓Bax, and ↑Bcl2 expression). Finally, TMZ amended FA-induced histopathological changes in kidneys. By mitigating functional alteration, oxidative stress, and preventing the development of inflammatory and apoptosis signals, TMZ provides dose-dependent defense against FA-induced AKI mainly via stimulation of hypoxia-inducible factor-1 alpha (HIF-1α)/heme oxygenase-1 (HO-1) pathway.

Protocatechuic acid protects against thioacetamide-induced chronic liver injury and encephalopathy in mice via modulating mTOR, p53 and the IL-6/ IL-17/ IL-23 immunoinflammatory pathway

Protocatechuic acid (PCA), a natural phenolic acid, is known for antioxidant, anti-inflammatory, anti-apoptotic, and anti-fibrotic activities. However, the protective mechanisms of PCA on thioacetamide (TAA)-induced liver/brain injury are not well addressed. Chronic liver injury was induced in mice by intraperitoneal injection of TAA (200 mg/kg, 3 times/week) for 8 weeks. Simultaneously, PCA (100, 150 mg/kg/day, p.o.) was given daily from the 4th week. Protocatechuic acid ameliorated liver and brain damage indicated by the decrease in serum activities of aminotransferases, gamma-glutamyl transferase, alkaline phosphatase, lactate dehydrogenase, levels of bilirubin, and ammonia concomitant with restoration of normal albumin levels. Additionally, PCA treatment ameliorated oxidative stress in liver and brain, confirmed by the decrease in malondialdehyde and nitric oxide levels and the increase in antioxidant activities. Moreover, PCA showed anti-inflammatory actions through downregulation of TNF-α expression in the liver and IL-6/IL-17/IL-23 levels in the brain, which is confirmed by the decrease in CD4⁺ T brain cell numbers. Most importantly, PCA treatment showed a significant decrease in mTOR level and number of LC3 positive cells in both liver and brain tissues. Consequently, PCA could inhibit mTOR-induced apoptosis, as it showed anti-apoptotic actions through downregulation of caspase-3 expression in liver and p53 expression in liver and brain. Furthermore, liver and brain tissues of treated mice showed restoration of normal histology. It can be concluded that, several mechanisms, including: antioxidant, anti-inflammatory, anti-autophagic and anti-apoptotic activities can be implicated in the hepato- and neuroprotective potentials of PCA.

Non-Alcoholic Fatty Liver Disease (NAFLD) in Patients with Psoriasis: A Review of the Hepatic Effects of Systemic Therapies

There is increasing interest in the association between psoriasis and non-alcoholic fatty liver disease (NAFLD), which is a prevalent liver disease characterized by excessive fat storage and inflammation that can progress to fibrosis and cancer. Patients with psoriasis have a two-fold higher risk to develop NAFLD and a higher risk to progress to more severe liver disease. Psoriasis and NAFLD share common risk factors such as smoking, alcohol consumption, and the presence of metabolic syndrome and its component disorders. In addition, both psoriasis and NAFLD hinge upon a systemic low-grade inflammation that can lead to a vicious cycle of progressive liver damage in NAFLD as well as worsening of the underlying psoriasis. Other important shared pathophysiological pathways include peripheral insulin resistance and oxidative stress. NAFLD should receive clinical awareness as important comorbidity in psoriasis. In this review, we assess the recent literature on the epidemiological and pathophysiological relationship of psoriasis and NAFLD, discuss the clinical implications of NAFLD in psoriasis patients, and summarize the hepatotoxic and hepatoprotective potential of systemic psoriasis therapies.

Vinpocetine attenuates fluoxetine-induced liver damage in rats; Role of Nrf2 and PPAR-γ

BACKGROUND

Fluoxetine (FLX) has been widely used as first-line treatment in cases of depression and other neuropsychiatric disorders. Although its safety has been approved, the use of FLX was associated with liver injury and chronic liver disease. Vinpocetine (Vinpo), a nootropic drug, possesses antioxidant and anti-inflammatory effects.

OBJECTIVE

This study aimed to evaluate the protective effects of Vinpo on FLX-induced liver damage pointing to the role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and nuclear factor erythroid 2-related factor 2 (Nrf2).

METHODS

Rats were randomized to four groups: control group, Vinpo group (20 mg/kg/day; orally), FLX group (10 mg/kg/day; orally), and Vinpo + FLX group.

RESULTS

FLX-induced liver damage was evidenced through elevated liver function biomarkers and induced hepatic histopathological changes. Concurrent Vinpo treatment resulted in a significant decrease in hepatotoxicity biomarkers and histopathological alterations. FLX-induced oxidative stress and inflammation were attenuated by Vinpo. In addition, Vinpo attenuated the hepatic NRF2 and HO-1 levels and up-regulated PPAR-γ expression. Moreover, FLX elevated Bcl-2-associated X protein (Bax) mRNA expression and decreased B-cell lymphoma 2 (Bcl2) mRNA expression were markedly reversed by Vinpo.

CONCLUSION

Vinpo possesses ameliorative effects against FLX-induced liver injury in rats. This effect may be due to attenuation of oxidative stress and inflammation, in addition to upregulation of PPAR-γ expression.

Simultaneous Modulation of NLRP3 Inflammasome and Nrf2/ARE Pathway Rescues Thioacetamide-Induced Hepatic Damage in Mice: Role of Oxidative Stress and Inflammation

Chronic tissue injury resulting in fibrosis of multiple organs, responsible for one-third of the death globally. Liver fibrosis is a common pathway/condition involved in all chronic liver diseases. Thioacetamide (TAA), a hepatotoxicant, was used to induce hepatic fibrosis. Anti-diabetic drug glibenclamide (GLB) possesses anti-inflammatory properties and inhibits NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome activation. Dimethyl fumarate (DMF), a multiple sclerosis drug, activates the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and maintains the antioxidant status in the cell. The present study was designed to investigate (i) role of NLRP3 inflammasome and Nrf2/ARE pathway in TAA-induced hepatotoxicity and liver fibrosis, (ii) mechanism involved in GLB and DMF mediated hepatoprotection against TAA-induced hepatotoxicity, and (iii) additional/synergistic hepatoprotective effect of combination treatment with NLRP3 inhibition + Nrf2 activation or GLB + DMF or MCC950 + 4OI to reverse/ameliorate the experimental liver fibrosis completely. TAA was administered intraperitoneally to mice for seven consecutive weeks, and treatments of GLB, DMF, GLB + DMF, MCC950, 4OI, and MCC950 + 4OI were provided for the last three consecutive weeks. The intervention with GLB, DMF, GLB + DMF, MCC950, 4OI, and MCC950 + 4OI significantly protected TAA-induced oxidative stress and inflammatory conditions by improving biochemical, histological, and immunoexpression changes in mice. The GLB, DMF, and GLB + DMF intervention exhibited a better protective effect compared with MCC950, 4OI, and MCC950 + 4OI, which revealed that this specific inhibitor/activator possesses only NLRP3 inflammasome inhibitory/Nrf2 activatory properties. In contrast, the clinical drug GLB and DMF have several other beneficial effects, which are independent of NLRP3 inhibition and Nrf2 activation.

Dimethyl fumarate reduces hepatocyte senescence following paracetamol exposure

Liver disease is a major cause of premature death. Oxidative stress in the liver represents a key disease driver. Compounds, such as dimethyl fumarate (DMF), can activate the antioxidant response and are used clinically to treat disease. In this study, we tested the protective properties of DMF before or after paracetamol exposure. Following DMF administration, Nrf2 nuclear translocation was tracked at the single-cell level and target gene transactivation confirmed. Next, the protective properties of DMF were examined following paracetamol exposure. Transcriptomic and biochemical analysis revealed that DMF rescue was underpinned by reduced Nf-kB and TGF-β signaling and cell senescence. Following on from these studies, we employed a Zebrafish model to study paracetamol exposure in vivo. We combined a genetically modified Zebrafish model, expressing green fluorescent protein exclusively in the liver, with automated microscopy. Pre-treatment with DMF, prior to paracetamol exposure, led to reduced liver damage in Zebrafish demonstrating protective properties.

Epac-1/Rap-1 signaling pathway orchestrates the reno-therapeutic effect of ticagrelor against renal ischemia/reperfusion model

Despite the renal expression of P₂Y₁₂, the purinergic receptor for adenosine diphosphate, few data are available to discuss the renotherapeutic potential of ticagrelor, one of its reversible blockers. Indeed, the tonic inhibitory effect of this receptor has been linked to the activation of exchange protein activated by cyclic adenosine monophosphate-1 (Epac-1) protein through the cyclic adenosine monophosphate cascade. Epac-1 is considered a crossroad protein, where its activation has been documented to manage renal injury models. Hence, the current study aimed to investigate the possible therapeutic effectiveness of ticagrelor, against renal ischemia/reperfusion (I/R) model with emphasis on the involvement of Epac-1 signaling pathway using R-CE3F4, a selective Epac-1 blocker. Accordingly, rats were randomized into four groups; viz., sham-operated, renal I/R, I/R post-treated with ticagrelor for 3 days, and ticagrelor + R-CE3F4. Treatment with ticagrelor ameliorated the I/R-mediated structural alterations and improved renal function manifested by the reduction in serum BUN and creatinine. On the molecular level, ticagrelor enhanced renal Epac-1 mRNA expression, Rap-1 activation (Rap-1-GTP) and SOCS-3 level. On the contrary, it inhibited the protein expression of JAK-2/STAT-3 hub, TNF-α and MDA contents, as well as caspase-3 activity. Additionally, ticagrelor enhanced the protein expression/content of AKT/Nrf-2/HO-1 axis. All these beneficial effects were obviously antagonized upon using R-CE3F4. In conclusion, ticagrelor reno-therapeutic effect is partly mediated through modulating the Epac-1/Rap-1-GTP, AKT/Nrf-2/HO-1 and JAK-2/STAT-3/SOCS-3 trajectories, pathways that integrate to afford novel explanations to its anti-inflammatory, anti-oxidant, and anti-apoptotic potentials.

Standard of care versus new-wave corticosteroids in the treatment of Duchenne muscular dystrophy: Can we do better?

BACKGROUND

Pharmacological corticosteroid therapy is the standard of care in Duchenne Muscular Dystrophy (DMD) that aims to control symptoms and slow disease progression through potent anti-inflammatory action. However, a major concern is the significant adverse effects associated with long term-use. MAIN: This review discusses the pros and cons of standard of care treatment for DMD and compares it to novel data generated with the new-wave dissociative corticosteroid, vamorolone. The current status of experimental anti-inflammatory pharmaceuticals is also reviewed, with insights regarding alternative drugs that could provide therapeutic advantage.

CONCLUSIONS

Although novel dissociative steroids may be superior substitutes to corticosteroids, other potential therapeutics should be explored. Repurposing or developing novel pharmacological therapies capable of addressing the many pathogenic features of DMD in addition to anti-inflammation could elicit greater therapeutic advantages.

Photocatalytic and biodegradation treatments of paracetamol: investigation of the in vivo toxicity

Medicines and drugs consumption by all populations of the world can be expected to result in the contamination of the environment since 30-90% of residual drugs will be found into wastewaters. In this study, we investigate the degradation of acetaminophen, selected as a xenobiotic model molecule, via two separate procedures, the TiO₂ impregnated on cellulosic paper photocatalysis, and specific bacterial biodegradation process. Results showed that for initial drug content of 400 mg/L and after 5 hours of processing, around 85% of paracetamol was photocatalytically degraded. The use of Pseudomonas putida E1.21 isolate allowed an abatement of around 92% after 32 h of processing. The acetaminophen toxicity conducted in vivo on laboratory mice showed a net decrease of the creatinine release and enzymes activities like ALP, ALT, AST, and LDH decreased significantly (p < 0.05) when mice were treated distinctly by acetaminophen treated with UV/TiO₂ and the Pseudomonas putida E1.21 strain compared with the control experiments. CAT, MDA, and AchE serum level disruption measurement indicated a serious affection of the mice antioxidant system. These results were found to be in correlation with the ones of the histological analysis of the liver and kidney.

Vinpocetine attenuates thioacetamide-induced liver fibrosis in rats

Liver fibrosis is associated with increased mortality and morbidity. However, there is not effective treatment so far. Vinpocetine (Vinpo) is a synthetic derivative of vinca alkaloid vincamine. Limited previous reports have shown some beneficial effects of Vinpo in different organ fibrosis, but the ability of Vinpo to inhibit liver fibrosis induced by thioacetamide (TAA) has not been reported, that is why we investigate the potential ability of this vinca alkaloid derivative to attenuate liver fibrosis. Hepatic fibrosis was induced in male Sprague Dawley rats by TAA (200 mg/kg; ip; 3 times/week) for 6 weeks. Daily treatments with Vinpo (10-20 mg/kg/day; orally) ameliorated TAA-induced hepatic oxidative stress and histopathological damage as indicated by a decrease in liver injury markers, LDH, hepatic MDA, and NOx levels, as well as increase anti-oxidative parameters. Besides, the anti-fibrotic efficacy of Vinpo was confirmed by decreasing hydroxyproline, and α-SMA. Also, the anti-inflammatory effect of Vinpo was explored by decreasing IL-6 and TNF-α levels. Our novel findings were that Vinpo decreased VEGF/Ki-67 expression in the liver confirming its effect on angiogenesis and proliferation. These findings reveal the anti-fibrotic effect of Vinpo against TAA-induced liver fibrosis in rats, and suggest the modulation of oxidative stress, inflammation, angiogenesis and proliferation as mechanistic cassette underlines this effect.

Dimethyl fumarate protects against intestinal ischemia/reperfusion lesion: Participation of Nrf2/HO-1, GSK-3β and Wnt/β-catenin pathway

OBJECTIVE

Dimethyl fumarate (DMFU), a known Nrf2 activator, has proven its positive effect in different organs against ischemia/reperfusion (Is/Re) injury. Nevertheless, its possible impact to modulate intestinal Is/Re-induced injury has not been previously demonstrated before. Hence, this study aimed to investigate DMFU mechanistic maneuver against intestinal Is/Re.

METHODS

To accomplish this goal, Wistar rats were allocated into four groups; Sham-operated (SOP), intestinal Is/Re (1 h/6 h), and 14 days pre-treated DMFU (15 and 25 mg/kg/day, p.o).

RESULTS

The mechanistic maneuver divulged that DMFU safeguarded the intestine partly via amplifying the expression/content of Nrf2 along with enhancing its downstream, HO-1 expression/content. In addition, DMFU lessened GSK-3β expression/content accompanied by enriching β-catenin expression/content. The antioxidant action was affirmed by enhancing total antioxidant capacity, besides reducing MDA, iNOS, and its by-product, NOx. The DMFU action entailed anti-inflammatory character manifested by down-regulation of expression/content NF-κB with subsequent rebating the contents of TNF-α, IL-1β, and P-selectin, as well as MPO activity. Moreover, DMFU had anti-apoptotic nature demonstrated through enriching Bcl-2 level and diminishing that of caspase-3.

CONCLUSION

DMFU purveyed tenable novel protective mechanisms and mitigated events associated with intestinal Is/Re mischief either in the lower or the high dose partly by amending of oxidative stress and inflammation through the modulation of Nrf2/HO-1, GSK-3β, and Wnt/β-catenin pathways.

Prevention of Autoimmune Diabetes in NOD Mice by Dimethyl Fumarate

Oxidative stress plays critical roles in the pathogenesis of diabetes. This study tested the hypothesis that by protecting β-cells against oxidative stress and inflammation, an Nrf2 activator, dimethyl fumarate (DMF), may prevent or delay the onset of type 1 diabetes in non-obese diabetic (NOD) mice. Firstly, islet isolation was conducted to confirm the antioxidative effects of DMF oral administration on islet cells. Secondly, in a spontaneous diabetes model, DMF (25 mg/kg) was fed to mice once daily starting at the age of 8 weeks up to the age of 22 weeks. In a cyclophosphamide-induced accelerated diabetes model, DMF (25 mg/kg) was fed to mice twice daily for 2 weeks. In the islet isolation study, DMF administration improved the isolation yield, attenuated oxidative stress and enhanced GCLC and NQO1 expression in the islets. In the spontaneous model, DMF significantly reduced the onset of diabetes compared to the control group (25% vs. 54.2%). In the accelerated model, DMF reduced the onset of diabetes from 58.3% to 16.7%. The insulitis score in the islets of the DMF treatment group (1.6 ± 0.32) was significantly lower than in the control group (3.47 ± 0.21). The serum IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-9, IL-12p70, IFN-γ, TNF-α, MCP-1 and CXCL16 levels in the DMF-treated group were lower than in the control group. In conclusion, DMF may protect islet cells and reduce the incidence of autoimmune diabetes in NOD mice by attenuating insulitis and proinflammatory cytokine production.

Calming the (Cytokine) Storm: Dimethyl Fumarate as a Therapeutic Candidate for COVID-19

COVID-19 has rapidly spread worldwide and incidences of hospitalisation from respiratory distress are significant. While a vaccine is in the pipeline, there is urgency for therapeutic options to address the immune dysregulation, hyperinflammation and oxidative stress that can lead to death. Given the shared pathogenesis of severe cases of COVID-19 with aspects of multiple sclerosis and psoriasis, we propose dimethyl fumarate as a viable treatment option. Currently approved for multiple sclerosis and psoriasis, dimethyl fumarate is an immunomodulatory, anti-inflammatory and anti-oxidative drug that could be rapidly implemented into the clinic to calm the cytokine storm which drives severe COVID-19.

Dimethyl Fumarate Attenuates Lung Inflammation and Oxidative Stress Induced by Chronic Exposure to Diesel Exhaust Particles in Mice

Air pollution is mainly caused by burning of fossil fuels, such as diesel, and is associated with increased morbidity and mortality due to adverse health effects induced by inflammation and oxidative stress. Dimethyl fumarate (DMF) is a fumaric acid ester and acts as an antioxidant and anti-inflammatory agent. We investigated the potential therapeutic effects of DMF on pulmonary damage caused by chronic exposure to diesel exhaust particles (DEPs). Mice were challenged with DEPs (30 μg per mice) by intranasal instillation for 60 consecutive days. After the first 30 days, the animals were treated daily with 30 mg/kg of DMF by gavage for the remainder of the experimental period. We demonstrated a reduction in total inflammatory cell number in the bronchoalveolar lavage (BAL) of mice subjected to DEP + DMF as compared to those exposed to DEPs alone. Importantly, DMF treatment was able to reduce lung injury caused by DEP exposure. Intracellular total reactive oxygen species (ROS), peroxynitrite (OONO), and nitric oxide (NO) levels were significantly lower in the DEP + DMF than in the DEP group. In addition, DMF treatment reduced the protein expression of kelch-like ECH-associated protein 1 (Keap-1) in lung lysates from DEP-exposed mice, whereas total nuclear factor κB (NF-κB) p65 expression was decreased below baseline in the DEP + DMF group compared to both the control and DEP groups. Lastly, DMF markedly reduced DEP-induced expression of nitrotyrosine, glutathione peroxidase-1/2 (Gpx-1/2), and catalase in mouse lungs. In summary, DMF treatment effectively reduced lung injury, inflammation, and oxidative and nitrosative stress induced by chronic DEP exposure. Consequently, it may lead to new therapies to diminish lung injury caused by air pollutants.

4-Octyl Itaconate Alleviates Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting Oxidative Stress and Inflammation

Background

Acute lung injury (ALI) is a fatal disease in the absence of pharmacological treatment. Oxidative stress and inflammation are closely related to ALI. Innate immune cells are the main source of reactive oxygen species (ROS). Macrophages play an extremely important role in ALI through the activation of inflammation and oxidative stress. Itaconate, a metabolite of tricarboxylic acid, has been reported to have strong antioxidant and anti-inflammatory effects. However, the role of itaconate in ALI is unclear. Herein, we use 4-octyl itaconate (OI), the cellular permeable derivate of itaconate, to study the effects of itaconate in vivo and in vitro.

Methods

We used OI to pretreat C57BL/6 mice and LPS-induced ALI models to illustrate the role of itaconate in acute lung injury. The mice were randomly divided into four groups: control group, OI (100 mg/kg) group, ALI Group, ALI + OI (50 mg/kg) group, and ALI + OI (100 mg/kg) group. RAW264.7 cells were used to further prove the role and mechanism of itaconate in vitro.

Results

According to the H&E staining of the lung, OI was observed to significantly reduce lung inflammation. The active oxygen content of tissues was also significantly reduced (P<0.05). OI reduced the accumulation of neutrophils and secretion of inflammatory factors in LPS-induced ALI (P<0.05). At the cellular level, OI also reduced oxidative stress and inflammation. Intervention with OI was also observed to upregulate the expression of nuclear factor erythroid 2-related factor-2 (Nrf-2) and Nrf-2 target genes in the lung tissue and RAW264.7 cells.

Conclusion

OI alleviates LPS-induced ALI. Moreover, the antioxidant and anti-inflammatory effects of OI might depend on the activation of Nrf-2. Therefore, OI might have therapeutic potential for the treatment of ALI.

Dimethyl Fumarate and Its Esters: A Drug with Broad Clinical Utility?

Fumaric acid esters (FAEs) are small molecules with anti-oxidative, anti-inflammatory and immune-modulating effects. Dimethyl fumarate (DMF) is the best characterised FAE and is approved and registered for the treatment of psoriasis and Relapsing-Remitting Multiple Sclerosis (RRMS). Psoriasis and RRMS share an immune-mediated aetiology, driven by severe inflammation and oxidative stress. DMF, as well as monomethyl fumarate and diroximel fumarate, are commonly prescribed first-line agents with favourable safety and efficacy profiles. The potential benefits of FAEs against other diseases that appear pathogenically different but share the pathologies of oxidative stress and inflammation are currently investigated.

Tiron protects against nicotine-induced lung and liver injury through antioxidant and anti-inflammatory actions in rats in vivo

AIMS

Tobacco smoking is a major health problem associated with lung and liver damage. Lung and liver damage secondary to tobacco smoking is mediated through nicotine-induced oxidative stress. Therefore, we hypothesized that antioxidant treatment with tiron may improve nicotine-induced lung and liver damage.

MATERIALS AND METHODS

Rats were divided into six groups, a control, nicotine (10 mg/kg/day, i.p.; for 8 weeks) and tiron (100 or 200 mg/kg/day, i.p.; for 8 weeks) with or without nicotine administration.

KEY FINDINGS

Tiron improved survival rate and attenuated lung and liver damage as reflected by decreased total and differential cell counts, lactate dehydrogenase (LDH) activity in bronchoalveolar lavage fluid (BALF) and decreased alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum; also histopathological examination confirmed the protective effect of tiron in lung and liver tissues of nicotine treated rats. Tiron attenuated dyslipidemia, which is associated with nicotine. These ameliorative effects of tiron may be mainly due to its antioxidant effect as proved by a significant decrease in malondialdehyde (MDA) content, reactive oxygen species (ROS) and total nitrite/nitrate (NOx) levels, and increase in reduced glutathione (GSH) level, catalase (CAT) and superoxide dismutase (SOD) activities. This is likely related to suppression of protein levels of NADPH oxidase enzyme (NOX1), inducible nitric oxide synthase (iNOS), nuclear factor kappa B (NF-κB) and tumor necrosis factor alpha (TNF-α); and up-regulation of protein levels of nuclear factor erythroid-2 (Nrf2).

SIGNIFICANCE

This makes tiron (synthetic analogue of vitamin E) good candidate for future use to minimize nicotine's hazards among smokers.

The deleterious effect of stress-induced depression on rat liver: Protective role of resveratrol and dimethyl fumarate via inhibiting the MAPK/ERK/JNK pathway

This study aimed to uncover the protective potentiality of resveratrol and dimethyl fumarate (DMF) in the liver of a chronic unpredictable mild stress (CUMS)-induced depression animal model. Resveratrol and DMF significantly alleviated CUMS-induced behavioral abnormalities in stressed rats through improving sucrose preference in sucrose preference test and decreasing immobility time in a forced swimming test. They also mitigated serum corticosterone levels and elevated serum serotonin levels, which were formerly disturbed in CUMS rats. The hepatoprotective effect is evidenced by improvement in hepatic histopathological examinations, as well as normalized serum alanine aminotransferase and aspartate aminotransferase activities. Molecular signaling of resveratrol and DMF was estimated by diminishing hepatic expression of phosphorylated p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase1/2 (ERK1/2), and c-Jun N-terminal kinase (JNK). Consequently, they improved the hepatic antioxidant and anti-inflammatory activities as elaborated by the normalization of total antioxidant capacity, glutathione, malondialdehyde, nuclear factor-κB, tumor necrosis factor-α, and myeloperoxidase levels. In addition, they inhibited hepatocyte apoptosis as evidenced by the increased expression of B-cell lymphoma 2, the decreased expression of Bax, as well as the suppressed activity of caspase-3. In conclusion, resveratrol and DMF purveyed a significant anti-depressant effect, which may be mediated, at least in part, via inhibiting the MAPK/ERK/JNK pathway in the CUMS rat model.

Targeting Heme Oxygenase-1 in the Arterial Response to Injury and Disease

Heme oxygenase-1 (HO-1) catalyzes the degradation of heme into carbon monoxide (CO), iron, and biliverdin, which is rapidly metabolized to bilirubin. The activation of vascular smooth muscle cells (SMCs) plays a critical role in mediating the aberrant arterial response to injury and a number of vascular diseases. Pharmacological induction or gene transfer of HO-1 improves arterial remodeling in animal models of post-angioplasty restenosis, vascular access failure, atherosclerosis, transplant arteriosclerosis, vein grafting, and pulmonary arterial hypertension, whereas genetic loss of HO-1 exacerbates the remodeling response. The vasoprotection evoked by HO-1 is largely ascribed to the generation of CO and/or the bile pigments, biliverdin and bilirubin, which exert potent antioxidant and anti-inflammatory effects. In addition, these molecules inhibit vascular SMC proliferation, migration, apoptosis, and phenotypic switching. Several therapeutic strategies are currently being pursued that may allow for the targeting of HO-1 in arterial remodeling in various pathologies, including the use of gene delivery approaches, the development of novel inducers of the enzyme, and the administration of unique formulations of CO and bilirubin.

Anti-apoptotic effect of vinpocetine on cisplatin-induced hepatotoxicity in mice: The role of Annexin-V, Caspase-3, and Bax

Hepatic damage is one of the most common complications related to cisplatin (Cis) use. Recently, liver protection lines are being discovered to avoid hepatic cell death as a result of oxidative, inflammatory, and apoptotic disturbance. Limited data reported the hepatoprotective effect of vinpocetine (Vin) in acute liver injury models. This study was designed to determine the potential protective effect of Vin (10-30 mg/kg, orally) against Cis-induced liver injury (10 mg/kg, IP) in mice. Vin administration for 1 week before Cis injection until the end of the experiment. On the 6th day after Cis injection, mice were anesthetized, blood and tissue samples were collected. Hepatic function, histological changes, oxidative stress, inflammation, and apoptotic markers were investigated. Vin administration ameliorated liver injury as indicated by decreased liver injury parameters; serum aminotransferases, ALK-P, GGT, and bilirubin, restored the anti-oxidant status by decrease MDA and NO_x , and increased GSH and SOD, inhibited inflammation (IL-6, TNF-α, NFκB-p65, and iNOS) and apoptosis (Annexin-V, Bax, and Caspase-3) parameters. Vin confers dose-dependent protection against Cis-induced liver injury. The hepatoprotective effect of Vin involved anti-oxidative, anti-inflammatory, and anti-apoptotic activities.

Dimethyl fumarate ameliorates diabetes-associated vascular complications through ROS-TXNIP-NLRP3 inflammasome pathway

Vascular complications are a leading cause of morbidity and mortality among diabetic patients. This work aimed to investigate possible influences of dimethyl fumarate (DMF) on streptozotocin (STZ) diabetes-associated vascular complications in rats, exploring its potential to modulate ROS-TXNIP-NLRP3 inflammasome pathway. Two weeks after induction of diabetes (via a single injection of 50 mg/kg STZ, i.p.), diabetic rats were administered either DMF (25 mg/kg/day) or its vehicle for further eight weeks. Age-matched normal and DMF-administered non-diabetic rats served as controls. DMF treatment elicited a mild ameliorative effect on diabetic glycemia. DMF reduced serum TG and AGE levels and enhanced serum HDL-C concentrations in diabetic rats. Moreover, DMF significantly diminished aortic levels of ROS and MDA and restored aortic GSH, SOD and Nrf2 to near-normal levels in STZ rats. Aortic mRNA levels of TXNIP, NLRP3 and NF-κB p65 in diabetic rats were significantly reduced by DMF treatment. Serum and aortic protein levels of TXNIP and aortic contents of IL-1β, iNOS, NLRP3 and TGF-β1 were significantly lower in DMF-diabetic animals than non-treated diabetic rats. Furthermore, protein expression of TNF-α and caspase-3 in diabetic aortas was greatly attenuated by DMF administration. DMF enhanced eNOS mRNA and protein levels and increased bioavailable NO in diabetic aortas. Functionally, DMF attenuated contractile responses of diabetic aortic rings to KCl and phenylephrine and enhanced their relaxant responses to acetylcholine. DMF also mitigated diabetes-induced fibrous tissue proliferation in aortic tunica media. Collectively, these findings demonstrate that DMF offered vasculoprotective influences on diabetic aortas via attenuation of ROS-TXNIP-NLRP3 inflammasome pathway.

Grape-Leaf Extract Attenuates Alcohol-Induced Liver Injury via Interference with NF-κB Signaling Pathway

Grape (Vitis vinifera) leaf extracts (GLEs) are known to be rich in phenolic compounds that exert potent antioxidant effects. Given the vulnerability of the liver to oxidative damage, antioxidants have been proposed as therapeutic agents and coadjuvant drugs to ameliorate liver pathologies. The current study was designed to characterize secondary metabolites and investigate the hepatoprotective effects of GLE and its underlying mechanisms. The secondary metabolites were profiled using HPLC–PDA–ESI-MS, and forty-five compounds were tentatively identified. In experimental in vivo design, liver injury was induced by oral administration of high doses of ethanol (EtOH) for 12 days to male Sprague Dawley rats that were split into five different groups. Blood samples and livers were then collected, and used for various biochemical, immunohistochemical, and histopathological analyses. Results showed that GLE-attenuated liver injury and promoted marked hepatic antioxidant effects, in addition to suppressing the increased heat-shock protein-70 expression. Moreover, GLE suppressed EtOH-induced expression of nuclear factor-κB (NF-κB) p65 subunit and proinflammatory cytokine tumor necrosis factor-α. Caspase-3 and survivin were enhanced by EtOH intake and suppressed by GLE intake. Finally, EtOH-induced histopathological changes in liver sections were markedly normalized by GLE. In conclusion, our results suggested that GLE interferes with NF-κB signaling and induces antioxidant effects, which both play a role in attenuating apoptosis and associated liver injury in a model of EtOH-induced liver damage in rats.

Montelukast ameliorates Concanavalin A-induced autoimmune hepatitis in mice via inhibiting TNF-α/JNK signaling pathway

BACKGROUND

Concanavalin A (ConA) is a well-established model to induce autoimmune hepatitis (AIH) in mice which mimics pathological alterations that occur in human. The pathogenesis of ConA-induced AIH involves many signaling pathways. Montelukast is a leukotriene receptor antagonist that is mainly used in the management of asthma. The antioxidant, anti-inflammatory and anti-apoptotic effects of montelukast have been reported in previous studies. Lately, montelukast has been documented to confer protection against various inflammatory diseases. Up to date, no study has explored the effect of montelukast on AIH induced by ConA.

AIM AND METHOD

This study aims to detect the protective effects of montelukast (10 mg/kg) on ConA (20 mg/kg)- induced AIH in mice and to demonstrate its hepatoprotective mechanisms. Hepatic function, histological changes, oxidative stress, inflammation, autophagy, and apoptotic markers were investigated.

RESULTS

Hepatic function and histological data revealed that treatment with montelukast significantly attenuated ConA-induced hepatic damage. Montelukast significantly reduced JNK level and NFκB p65 expression, and inhibited proinflammatory cytokines (TNF-α and IL-6) as well as oxidative stress (MDA, NO, and GSH). Moreover, inflammatory cells (CD4+ infiltration and the levels of apoptotic markers (Bax and caspase-3) besides autophagy biomarkers (Beclin1 and LC3) were reduced.

CONCLUSION

Our results suggest that montelukast could be a potential therapeutic drug against the ConA-induced AIH through its anti-oxidant, anti-inflammatory, anti- autophagy as well as anti-apoptotic properties.

Tetrandrine Ameliorates Airway Remodeling of Chronic Asthma by Interfering TGF-β1/Nrf-2/HO-1 Signaling Pathway-Mediated Oxidative Stress

Background

Imbalanced oxidative stress and antioxidant defense are involved in airway remodeling in asthma. It has been demonstrated that Tetrandrine has a potent role in antioxidant defense in rheumatoid arthritis and hypertension. However, the correlation between Tetrandrine and oxidative stress in asthma is utterly blurry. This study aimed to investigate the role of Tetrandrine on oxidative stress-mediated airway remolding.

Materials and Methods

Chronic asthma was established by ovalbumin (OVA) administration in male Wistar rats. Histopathology was determined by HE staining. Immunofluorescence was employed to detect the expression of α-SMA and Nrf-2. Level of oxidative stress and matrix metalloproteinases were examined by ELISA kits. Cell viability and cell cycle of primary airway smooth muscle cells (ASMCs) were evaluated by CCK8 and flow cytometry, respectively. Signal molecules were detected using western blot.

Results

Tetrandrine effectively impairs OVA-induced airway inflammatory and airway remodeling by inhibiting the expression of CysLT1 and CysLTR1. The increase of oxidative stress and subsequent enhancement of MMP9 and TGF-β1 expression were rescued by the administration of Tetrandrine in the rat model of asthma. In in vitro experiments, Tetrandrine markedly suppressed TGF-β1-evoked cell viability and cell cycle promotion of ASMCs in a dose-dependent manner. Furthermore, Tetrandrine promoted Nrf-2 nuclear transcription and activated its downstream HO-1 in vivo and in vitro.

Conclusion

Tetrandrine attenuates airway inflammatory and airway remodeling in rat model of asthma and TGF-β1-induced cell proliferation of ASMCs by regulating oxidative stress in primary ASMCs, suggesting that Tetrandrine possibly is an effective candidate therapy for asthma.

Dimethyl fumarate attenuates lipopolysaccharide-induced mitochondrial injury by activating Nrf2 pathway in cardiomyocytes

AIMS

To determine whether dimethyl fumarate (DMF) can protect against lipopolysaccharide (LPS) -induced myocardial injury.

MAIN METHODS

H9c2 cells pretreated with or without DMF were stimulated with LPS. Cell viability and apoptosis were evaluated. Nrf2 and HO-1 expression were detected using Western blotting. Mitochondrial morphology, mitochondrial superoxide production were observed using confocal microscope. Mitochondrial respiration function was measured using Seahorse bioanalyzer.

KEY FINDINGS

(1) The cell viability decreased, LDH release and apoptosis increased in LPS- challenged H9c2 cells. DMF pretreatment brought a higher cell viability, and a lower LDH leakage and apoptosis than those of LPS group (P < 0.01). (2) DMF pretreatment resulted in an increased Nrf2 and HO-1 expression, and enhanced nuclear Nrf2 level in LPS-challenged cells (P < 0.01). (3) Nrf2-siRNA could inhibit DMF-induced enhancement of HO-1 expression and cell viability, and partly abolish DMF-induced reduction of LDH leakage and apoptosis. (4) ERK1/2 inhibitor PD98059 could not only prevent the DMF-induced enhancement of nuclear Nrf2 and HO-1, but also inhibit DMF-induced increase in cell viability. (5) Compared with LPS-challenged cells, DMF pretreatment caused a lower production of mitochondrial superoxide and a higher mitochondrial membrane potential, which could be abolished by Nrf2-siRNA. (6) DMF could attenuate LPS-induced mitochondrial fragmentation and improve mitochondrial respiration function by enhancement of the oxygen consumption rate of basal respiration and ATP production in LPS-challenged cells (P < 0.01).

SIGNIFICANCE

DMF protects cardiomyocytes against LPS-induced damage. ERK1/2-dependent activation of Nrf2/HO-1 pathway is responsible for DMF-induced cardioprotection via reduction of oxidative stress, improvement of mitochondrial morphology and energy metabolism.