Morin alleviates hepatic ischemia/reperfusion-induced mischief: In vivo and in silico contribution of Nrf2, TLR4, and NLRP3

Natural products as non-covalent and covalent modulators of the KEAP1/NRF2 pathway exerting antioxidant effects

By controlling several antioxidant and detoxifying genes at the transcriptional level, including NAD(P)H quinone oxidoreductase 1 (NQO1), multidrug resistance-associated proteins (MRPs), UDP-glucuronosyltransferase (UGT), glutamate-cysteine ligase catalytic (GCLC) and modifier (GCLM) subunits, glutathione S-transferase (GST), sulfiredoxin1 (SRXN1), and heme-oxygenase-1 (HMOX1), the KEAP1/NRF2 pathway plays a crucial role in the oxidative stress response. Accordingly, the discovery of modulators of this pathway, activating cellular signaling through NRF2, and targeting the antioxidant response element (ARE) genes is pivotal for the development of effective antioxidant agents. In this context, natural products could represent promising drug candidates for supplementation to provide antioxidant capacity to human cells. In recent decades, by coupling in silico and experimental methods, several natural products have been characterized to exert antioxidant effects by targeting the KEAP1/NRF2 pathway. In this review article, we analyze several natural products that were investigated experimentally and in silico for their ability to modulate KEAP1/NRF2 by non-covalent and covalent mechanisms. These latter represent the two main sections of this article. For each class of inhibitors, we reviewed their antioxidant effects and potential therapeutic applications, and where possible, we analyzed the structure-activity relationship (SAR). Moreover, the main computational techniques used for the most promising identified compounds are detailed in this survey, providing an updated view on the development of natural products as antioxidant agents.

Therapeutic Potential of Morin Hydrate Against Rifampicin Induced Hepato and Renotoxicity in Albino Wistar Rats: Modulation of Organ Function, Oxidative Stress and Inflammatory Response

Tuberculosis (TB) is a challenging public health issue, particularly in poor and developing countries. Rifampicin (RIF) is one of the most common first-line anti-TB drugs but it is known for its adverse effects on the hepato-renal system. The present study investigated the efficacy of morin hydrate (MH) in protecting hepato-renal damage inflicted by RIF in rats. RIF (50 mg/kg), and a combination of RIF (50 mg/kg) and MH (50 mg/kg) were administered orally for 4 weeks in rats. Silymarin (50 mg/kg) was used as a positive control. Increased levels of serological parameters such as AST, ALT, ALP, LDH, GGT, bilirubin, triglyceride, total cholesterol, urea, uric acid, creatinine, TNF-α, IFN-γ, IL-6 along with the decreased level of IL-10, total protein and albumin were used as markers of hepatic and renal injury. Oxidative damage in the tissues was measured by the increase in lipid peroxidation and decline in GSH, SOD and catalase activities. Histopathology of liver slices was used to study hepatic architecture. Four-week RIF treatment produced altered serological parameters with an increase in pro-inflammatory cytokines in serum suggesting hepatotoxicity and nephrotoxicity. The antioxidant status of the liver and kidney (increased lipid peroxidation and decline in GSH, SOD and catalase) was compromised. Cellular damage and necrosis were observed in liver slices. MH supplementation with RIF improved hepato-renal functions by restoring the serum and tissue markers towards normal values. Histological observations authenticated the results. MH supplementation also reduced the production of pro-inflammatory cytokines. Thus, the results revealed that MH provides protection against RIF-induced hepato-renal injury.

NLRP3 inhibitors: Unleashing their therapeutic potential against inflammatory diseases

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome has been linked to the release of pro-inflammatory cytokines and is essential for innate defence against infection and danger signals. These secreted cytokines improve the inflammatory response caused by tissue damage and associated inflammation. Consequently, the development of NLRP3 inflammasome inhibitors are viable option for the treatment of diverse inflammatory disorders. The significant anti-inflammatory effects of the NLRP3 inhibitors have severe side effects. Hence, the application of NLRP3 inhibitors against inflammatory disease has not yet been understood and most of the developed inhibitors are unsuccessful in clinical trials. The processes behind the NLRP3 complex, priming, and activation are the main emphasis of this review, which also covers therapeutical inhibitors of the NLRP3 inflammasome and potential therapeutic strategies for directing the NLRP3 inflammasome towards clinical development.

New insights into the role of berberine against 3-nitropropionic acid-induced striatal neurotoxicity: Possible role of BDNF-TrkB-PI3K/Akt and NF-κB signaling

Berberine (Berb) is a major alkaloid with potential protective effects against multiple neurological disorders. Nevertheless, its positive effect against 3-nitropropionic acid (3NP) induced Huntington's disease (HD) modulation has not been fully elucidated. Accordingly, this study aimed to assess the possible action mechanisms of Berb against such neurotoxicity using an in vivo rats model pretreated with Berb (100 mg/kg, p.o.) alongisde 3NP (10 mg/kg, i.p.) at the latter 2 weeks to induce HD symptoms. Berb revealed its capacity to partially protect the striatum as mediated via the activation of BDNF-TrkB-PI3K/Akt signaling and amelioration of neuroinflammation status by blocking NF-κB p65 with a concomitant reduction in its downstream cytokines TNF-α and IL-1β. Moreover, its antioxidant potential was evidenced from induction of Nrf2 and GSH levels concurrent with a reduction in MDA level. Furthermore, Berb anti-apoptotic effect was manifested through the induction of pro-survival protein (Bcl-2) and down-regulation of the apoptosis biomarker (caspase-3). Finally, Berb intake ascertained its striatum protective action by improving the motor and histopathological abnormalities with concomitant dopamine restoration. In conclusion, Berb appears to modulate 3NP-induced neurotoxicity by moderating BDNF-TrkB-PI3K/Akt signaling besides its anti-inflammatory, antioxidant, as well as anti-apoptotic effect.

Ameliorative Effect of D-Carvone against Hepatic Ischemia-Reperfusion-Induced Injury in Rats

BACKGROUND

D-carvone is a monoterpene that exists in the essential oils of several plant species. Hepatic ischemia-reperfusion (Hep I/R) takes place clinically during different scenarios of liver pathologies. The aim of the current investigation is to disclose the hepato-protective actions of carvone against Hep I/R-induced damage and to reveal the underlying mechanism.

MATERIAL AND METHODS

Rats were assigned into five groups: sham and carvone plus sham groups, in which rats were administered either saline or carvone orally for three weeks prior to the induction of Hep I/R. In the Hep I/R group, rats were administered saline orally prior to the Hep I/R induction operation. The carvone 25 plus Hep I/R and Carvone 50 plus Hep I/R groups were administered carvone (25 and 50 mg/kg, respectively) for three weeks, followed by the induction of Hep I/R.

RESULTS

Liver ischemic animals demonstrated impaired liver function, several histopathological variations, and reduced levels of antioxidant enzyme activities. Furthermore, the Hep I/R groups showed the elevated gene expression of high-mobility group box 1 (HMGB1), toll-like receptors 4 (TLR4), nuclear factor kappa B (NFκB), and LR family pyrin domain containing 3 (NLP3), with subsequent escalated adhesion molecule 1 (ICAM-1), neutrophil infiltration, and several inflammatory mediators, including interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α), as well as apoptotic markers. Pretreatment with D-carvone alleviated ischemia/reperfusion-induced impaired liver function, diminished the histopathological deviations, and augmented the antioxidant enzymes. In addition, D-carvone mitigated the gene expression of HMGB1, TLR4, NFκB, and NLP3, with a subsequent reduction in ICAM-1, neutrophils infiltration, inflammatory mediators, and apoptotic markers.

CONCLUSION

Rats pretreated with D-carvone exhibited hepato-protective actions against Hep I/R-induced damage via the downregulation of HMGB1, TLR4, NFκB, NLP3, associated inflammatory mediators, and apoptotic markers.

NLRP3: Role in ischemia/reperfusion injuries

NLR family pyrin domain containing 3 (NLRP3) is expressed in immune cells, especially in dendritic cells and macrophages and acts as a constituent of the inflammasome. This protein acts as a pattern recognition receptor identifying pathogen-associated molecular patterns. In addition to recognition of pathogen-associated molecular patterns, it recognizes damage-associated molecular patterns. Triggering of NLRP3 inflammasome by molecules ATP released from injured cells results in the activation of the inflammatory cytokines IL-1β and IL-18. Abnormal activation of NLRP3 inflammasome has been demonstrated to stimulate inflammatory or metabolic diseases. Thus, NLRP3 is regarded as a proper target for decreasing activity of NLRP3 inflammasome. Recent studies have also shown abnormal activity of NLRP3 in ischemia/reperfusion (I/R) injuries. In the current review, we have focused on the role of this protein in I/R injuries in the gastrointestinal, neurovascular and cardiovascular systems.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

The Role of NLRP3 Inflammasome Activation Pathway of Hepatic Macrophages in Liver Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) is considered an inherent component involved in liver transplantation, which induce early organ dysfunction and failure. And the accumulating evidences indicate that the activation of host innate immune system, especially hepatic macrophages, play a pivotal role in the progression of LIRI. Inflammasomes is a kind of intracellular multimolecular complexes that actively participate in the innate immune responses and proinflammatory signaling pathways. Among them, NLRP3 inflammasome is the best characterized and correspond to regulate caspase-1 activation and the secretion of proinflammatory cytokines in response to various pathogen-derived as well as danger-associated signals. Additionally, NLRP3 is highly expressed in hepatic macrophages, and the assembly of NLRP3 inflammasome could lead to LIRI, which makes it a promising therapeutic target. However, detailed mechanisms about NLRP3 inflammasome involving in the hepatic macrophages-related LIRI is rarely summarized. Here, we review the potential role of the NLRP3 inflammasome pathway of hepatic macrophages in LIRI, with highlights on currently available therapeutic options.

Selenium nanoparticles impart robust neuroprotection against deltamethrin-induced neurotoxicity in male rats by reversing behavioral alterations, oxidative damage, apoptosis, and neuronal loss

This study investigated the neuroprotective role of selenium nanoparticles (SeNPs) on deltamethrin-induced neurotoxicity in rats. A total of 32 adult male Wister rats were allocated into the following four groups: 1) control, 2) deltamethrin (0.6 mg/kg), 3) SeNPs (0.5 mg/kg), and 4) deltamethrin + SeNPs. All agents were administered orally three times per week for 2 months. Locomotor behavior, anxiety-like behavior, biochemical parameters, including brain oxidative damage biomarkers (Malondialdehyde (MDA) and reduced glutathione (GSH)), brain acetylcholinesterase (AChE), and brain genotoxicity were evaluated. The gene expression levels of IGF-1 and Bcl₂ were also determined. Moreover, a brain histopathological examination associated with the immunohistochemical determination of Bax in brain tissue was performed. Deltamethrin-intoxicated rats showed a reduction in the locomotor activity associated with a highly anxious state. They also displayed a disturbance in the brain redox state with a decrease in the brain AChE levels and a high DNA fragmentation percentage. Furthermore, they showed a decrement in the immunohistochemical GFAP levels as well as IGF-1 and Bcl₂ gene expression levels with an increase in the immunohistochemical Bax levels. All these changes were confirmed by brain histopathology. Interestingly, SeNPs ameliorated all these changes and restored the normal brain architecture. In conclusion. SeNPs possess a potent medicinal activity due to their antioxidant and anti-inflammatory activity. Therefore, SeNPs can be a potential agent in ameliorating deltamethrin-induced neurotoxicity.

Berberine-loaded nanostructured lipid carriers mitigate warm hepatic ischemia/reperfusion-induced lesion through modulation of HMGB1/TLR4/NF-κB signaling and autophagy

OBJECTIVE

Berberine (BBR) is a known alkaloid that has verified its protective effects against ischemia/reperfusion (I/RN) lesion in multiple organs but its poor oral bioavailability limited its use. Despite the previous works, its possible impact on the warm hepatic I/RN-induced lesion is not clear. Accordingly, a nanostructured lipid carrier of BBR (NLC BBR) was developed for enhancing its efficiency and to inspect its protective mechanistic against warm hepatic I/RN.

METHODS

NLC BBR formula was evaluated pharmaceutically. Wistar rats were orally pre-treated with either BBR or NLC BBR (100 mg/kg) for 2 weeks followed by hepatic I/RN (30 min/24 h). Biochemical, ELISA, qPCR, western blot, histopathological, and immunohistochemical studies were performed.

KEY FINDINGS

Optimized NLC BBR was prepared with a particle size of 130 ± 8.3 nm. NLC BBR divulged its aptitude to safeguard the hepatic tissues partly due to anti-inflammatory capacity through downsizing the HMGB1/TLR4/NF-κB trajectory with concomitant rebating of TNF-α, iNOS, COX-2, and MPO content. Furthermore, NLC BBR antiapoptotic trait was confirmed by boosting the prosurvival protein (Bcl-2) and cutting down the pro-apoptotic marker (Bax). Moreover, its antioxidant nature was confirmed by TAC uplifting besides MDA subsiding. On the other hand, NLC BBR action embroiled autophagy flux spiking merit exemplified in Beclin-1 and LC3-II enhancement. Finally, NLC BBR administration ascertained its hepatocyte guarding action by recovering the histopathological ailment and diminishing serum transaminases.

CONCLUSION

NLC BBR purveyed reasonable shielding mechanisms and subsided incidents contemporaneous to warm hepatic I/RN lesion in part, by moderating HMGB1/TLR4/NF-κB inflammatory signaling, autophagy, and apoptosis.

Mangiferin mitigates di-(2-ethylhexyl) phthalate-induced testicular injury in rats by modulating oxidative stress-mediated signals, inflammatory cascades, apoptotic pathways, and steroidogenesis

Di-(2-ethylhexyl) phthalate (DEHP) is an endocrine disruptor that causes reproductive defects in male animal models. This study was conducted to explore the plausible modulatory effects of mangiferin (MF) against DEHP-induced testicular injury in rats. Thirty-two adult male albino rats were allocated into four groups. Two groups were given DEHP (2 g/kg/day, p.o) for 14 days. One of these groups was treated with MF (20 mg/kg/day, i.p) for 7 days before and 14 days after DEHP administration. A vehicle-treated control was included, and another group of rats was given MF only. Results revealed that MF treatment suppressed oxidative testicular injury by amplifying the mRNA expression of nuclear factor-erythroid 2 related factor-2 (Nrf2) and increasing hemoxygenase-1 (HO-1), glutathione, and total antioxidant capacity (TAC) levels. This treatment also enhanced superoxide dismutase activity, but it decreased malondialdehyde and nitric oxide levels. MF had an anti-inflammatory characteristic, as demonstrated by the downregulation of the mRNA of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The content of tumor necrosis factor-alpha also decreased. MF modulated the apoptotic pathway by suppressing the mRNA of cytochrome c (Cyt c), Fas ligand content, Bax IHC expression, caspase-3 activity and cleaved caspase-3 IHC expression. It also upregulated the expression levels of heat-shock protein 70 (HSP70) and B-cell lymphoma 2. Moreover, MF upregulated the mRNA expression levels of HSP70 and c-kit and enriched the content of steroidogenic acute regulatory (StAR) protein, which were reflected in serum testosterone levels. This result indicated that MF played crucial roles in steroidogenesis and spermatogenesis. Besides, the activities of testicular marker enzymes, namely, acid and alkaline phosphatases, and lactate dehydrogenase, significantly increased. Histopathological observations provided evidence supporting the biochemical and molecular measurements. In conclusion, MF provided protective mechanisms against the DEHP-mediated deterioration of testicular functions partially through its antioxidant, anti-inflammatory, and anti-apoptotic properties. It also involved the restoration of steroidogenesis and spermatogenesis through the modulation of Nrf2/HO-1, NF-κB/Cyt c/HSP70, and c-Kit signaling cascades.