Protective effect of rapamycin against acrylamide-induced hepatotoxicity: The associations between autophagy, apoptosis, and necroptosis

Saroglitazar mitigated NASH-associated hepatic injury in dexamethasone-treated rats via modulating autophagy, apoptosis, and necroptosis

This study aimed to evaluate the possible ameliorative effects of saroglitazar (SAR) on aspects of hepatic injury in dexamethasone (DEX)-induced nonalcoholic steatohepatitis (NASH) in rats. Wistar rats received SAR (2 or 4 mg/kg/day, orally) or metformin (MET, 500 mg/kg/day, orally) for one week before and concurrently with DEX administration (8 mg/kg/day, i.p., for 6 days. Control and drug control groups received vehicle or the higher dose of SAR, respectively. At the end of the experiment, an oral glucose tolerance test (OGTT) was conducted, serum hepatic function parameters and lipid profile were assessed, and hepatic histological changes were evaluated. Moreover, hepatic p-Akt/Akt ratios, malondialdehyde (MDA) content, SREBP-1, FOXO1, LC3, cleaved caspase-3, and p-MLKL protein levels were determined. Furthermore, hepatic immunohistochemical expressions of FOXO1, caspase-3, Bcl-2, LC3, and P62 were examined. SAR (mainly at 4 mg/kg/day) significantly improved Area under the OGTT curve (P < 0.0001), hepatic function parameters, lipid profile, and hepatic histopathological features in DEX-administered rats. Moreover, SAR significantly attenuated DEX-induced increases in hepatic MDA content (P < 0.05), SREBP-1 levels (P < 0.0001), and nuclear FOXO1, caspase-3, LC3, P62, and p-MLKL protein expressions (P < 0.0001). Furthermore, SAR significantly enhanced hepatic p-Akt/Akt ratio and Bcl-2 protein expression in DEX-administered rats (P < 0.0001). The higher dose of SAR showed greater hepatoprotective effects compared to its corresponding lower dose and MET in most assessments, approaching levels similar to the control group. SAR mitigated hepatic injury associated with DEX-induced NASH in rats, suggesting it might be a potential hepatoprotective drug for patients with or at high risk of NASH.

Intranasal Exendin-4 modifies necroptosis-mediated innate immune response to combat septic encephalopathy in rats: Role of mTORC1 in immunogenic and tolerogenic cell demise

Septic encephalopathy (SE) is a critical mental status associated with potential long-term cognitive deficits and higher mortality rates in ICU patients. The shortfall in comprehending its pathophysiology limits effective treatment options, however, GLP-1 agonists opened an entry point for future neurodegenerative disease management. This work aims to explore the mTORC1 prospective role in the pathogenesis of SE using rapamycin (RAPA) and investigate the involvement of this complex in exendin-4 (EX4) neurotherapeutic potential using cecal ligation and puncturing (CLP)-induced SE model, focusing on necroptosis as a novel intervention besides necrosis and apoptosis. EX4 was administered intranasally alone or preceded by RAPA, which was also solely given to male Sprague-Dawley rats subjected to CLP. First, opposite to the SE effect, RAPA inhibited mTORC1 and blunted TNF-α-induced necroptosis and Drp1, a mitochondrial fission marker. However, RAPA worsened the SE effect on endotoxemia, functional/cortical structures, and apoptotic/necrotic cell deaths. Second, EX4 increased mTORC1 assembly in the cerebral cortex and reduced sepsis-induced endotoxemia and behavioral/cerebral histopathology deficits in an mTOR-dependent manner. EX4 also reduced the inflammatory marker TNF-α and necroptosis as indicated by RIPK-1/RIPK-3/MLKL dephosphorylation and deactivated PGAM/Drp1 axis. Besides, EX4 turned off the apoptotic cue, caspase-3&8/cytochrome-C. However, RAPA pre-administration nullified the EX4 effect on apoptosis and HMGB1-induced necrosis. In conclusion, our research declares that targeting mTORC1 could be a promising approach for managing SE. Additionally, we highlight that the novel neuroprotective effect of EX4 in ameliorating SE is achieved by reducing necroptosis and utilizing the anti-apoptotic and anti-necrotic properties of mTORC1.

Acrylamide interferes with autophagy and induces apoptosis in Neuro-2a cells by interfering with TFEB-regulated lysosomal function

Acrylamide (ACR), a well-documented human neurotoxicant that is widely exists in starchy foods. More than 30% of human daily energy is provided by ACR-containing foods. Evidence indicated that ACR can induce apoptosis and inhibit autophagy, but the mechanisms are limited. Transcription Factor EB (TFEB) is a major transcriptional regulator of the autophagy-lysosomal biogenesis that regulates autophagy processes and cell degradation. Our study aimed to investigated the potential mechanisms of TFEB-regulated lysosomal function in ACR-caused autophagic flux inhibition and apoptosis in Neuro-2a cells. Our results found that ACR exposure inhibited the autophagic flux, as revealed by the elevated LC3-II/LC3-I and p62 levels and a notable increased autophagosomes. ACR exposure reduced the amounts of LAMP1 and mature cathepsin D and caused an accumulation of ubiquitinated proteins, which suggests lysosomal dysfunction. In addition, ACR increased cellular apoptosis via decreasing Bcl-2 expression, increasing Bax and cleaved caspase-3 expression, and raising the apoptotic rate. Interestingly, TFEB overexpression alleviated the ACR-induced lysosomal dysfunction, and then mitigated the autophagy flux inhibition and cellular apoptosis. On the other hand, TFEB knockdown exacerbated the ACR-induced lysosomal dysfunction, autophagy flux inhibition, and cellular apoptosis. These findings strongly suggested that TFEB- regulated lysosomal function is responsible for ACR-caused autophagic flux inhibition and apoptosis in Neuro-2a cells. The present study hopes to explore new sensitive indicators in the mechanism of ACR neurotoxicity and thus provide new targets for the prevention and treatment of ACR intoxication.

Acrylamide in food: Occurrence, metabolism, molecular toxicity mechanism and detoxification by phytochemicals

Acrylamide (ACR) is a common pollutant formed during food thermal processing such as frying, baking and roasting. ACR and its metabolites can cause various negative effects on organisms. To date, there have been some reviews summarizing the formation, absorption, detection and prevention of ACR, but there is no systematic summary on the mechanism of ACR-induced toxicity. In the past five years, the molecular mechanism for ACR-induced toxicity has been further explored and the detoxification of ACR by phytochemicals has been partly achieved. This review summarizes the ACR level in foods and its metabolic pathways, as well as highlights the mechanisms underlying ACR-induced toxicity and ACR detoxification by phytochemicals. It appears that oxidative stress, inflammation, apoptosis, autophagy, biochemical metabolism and gut microbiota disturbance are involved in various ACR-induced toxicities. In addition, the effects and possible action mechanisms of phytochemicals, including polyphenols, quinones, alkaloids, terpenoids, as well as vitamins and their analogs on ACR-induced toxicities are also discussed. This review provides potential therapeutic targets and strategies for addressing various ACR-induced toxicities in the future.

Acrylamide induced hepatotoxicity through oxidative stress: Mechanisms and interventions

SIGNIFICANCE

Acrylamide (AA) widely exists in the environment. Studies have demonstrated that AA has neurotoxicity and potential carcinogenicity in humans, and genotoxicity and severe hepatotoxicity in animals. As the critical metabolism organ for AA, the liver is the primary attacking target of AA. This review summarizes the recent advances in hepatotoxicity mechanism through AA-induced oxidative stress in rodent livers and hepatic cell lines, this is beneficial to assess risks of AA exposure and explore effective intervention methods for AA hepatotoxicity.

RECENT ADVANCES

Accumulating evidences have indicated that AA-induced oxidative stress is responsible for its hepatotoxicity. The changes in homological and biochemical indexes such as activities of hepatic antioxidant enzymes have been elucidated with the occurrence and development of oxidative stress. Also, the molecular mechanisms underlying AA-induced hepatotoxicity through oxidative stress have been mainly explained by apoptosis, inflammatory and autophagic pathways.

CRITICAL ISSUES

This review is focusing on the molecular mechanism of hepatotoxicity through AA-induced oxidative stress, this can provide a theoretical basis for the assessment of AA-induced health risk and finding potential intervention targets.

FUTURE DIRECTIONS

Epigenetic modifications like miRNAs and modulation of the gut microbiome involved in AA toxification pathway must be investigated, and will provide novel insights to unravel the toxification mechanism and intervention strategy for AA hepatotoxicity.

Neuroprotective and therapeutic effects of calcitriol in rotenone-induced Parkinson’s disease rat model

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Treatment of PD is challenging, as current treatment strategies are only symptomatic and do not stop disease development. Recent studies reported neuroprotective effects of calcitriol in PD through its antioxidant and anti-inflammatory properties. The exact pathomechanisms of PD are not yet fully understood. So, investigation of different molecular pathways is challenging. Sirtuin-1 (Sirt1) modulates multiple physiological processes, including programmed cell death, DNA repair, and inflammation. Furthermore, defective autophagy is considered a key pathomechanism in PD as it eliminates protein aggregation and dysfunctional cell organelles. The present study investigated the involvement of autophagy and Sirt1/NF-κB molecular pathway in rotenone-induced PD and explored the protective and restorative effects of calcitriol through these mechanisms. Therefore, behavioral tests were used to test the effect of calcitriol on motor disability and equilibrium. Furthermore, the histological and neuronal architecture was assessed. The expression of genes encoding neuroinflammation and autophagy markers was determined by qPCR while their protein levels were determined by Western blot analysis and immune-histochemical staining. Our results indicate that behavioral impairments and dopaminergic neuron depletion in the rotenone-induced PD model were improved by calcitriol administration. Furthermore, calcitriol attenuated rotenone-induced neuroinflammation and autophagy dysfunction in PD rats through up-regulation of Sirt1 and LC3 and down-regulation of P62 and NF-κB expression levels. Thus, calcitriol could induce a neuro-protective and restorative effect in the rotenone-induced PD model by modulating autophagy and Sirt1/NF-κB pathway.

Salvia chinensia Benth induces autophagy in esophageal cancer cells via AMPK/ULK1 signaling pathway

Salvia chinensia Benth (Shijianchuan in Chinese, SJC) has been used as a traditional anti-cancer herb. SJC showed good anti-esophageal cancer efficacy based on our clinical application. However, the current research on SJC is minimal, and its anti-cancer effect lacks scientific certification. This study aims to clarify the inhibitory effect of SJC on esophageal cancer and explore its underlying mechanism. Q-Orbitrap high-resolution LC/MS was used to identify the primary chemical constituents in SJC. Cell proliferation and colony formation assays showed that SJC could effectively inhibit the growth of esophageal tumor cells in vitro. To clarify its mechanism of action, proteomic and bioinformatic analyses were carried out by combining tandem mass labeling and two-dimensional liquid chromatography-mass spectrometry (LC-MS). Data are available via ProteomeXchange with identifier PXD035823. The results indicated that SJC could activate AMPK signaling pathway and effectively promote autophagy in esophageal cancer cells. Therefore, we further used western blotting to confirm that SJC activated autophagy in esophageal cancer cells through the AMPK/ULK1 signaling pathway. The results showed that P-AMPK and P-ULK1 were significantly up-regulated after the treatment with SJC. The ratio of autophagosomes marker proteins LC3II/I was significantly increased. In addition, the expression of the autophagy substrate protein P62 decreased with the degradation of autophagosomes. Using lentiviral transfection of fluorescent label SensGFP-StubRFP-LC3 protein and revalidation of LC3 expression before and after administration by laser confocal microscopy. Compared with the control group, the fluorescence expression of the SJC group was significantly enhanced, indicating that it promoted autophagy in esophageal cancer cells. Cell morphology and the formation of autophagosomes were observed by transmission electron microscopy. Our study shows that the tumor suppressor effect of SJC is related to promoting autophagy in esophageal tumor cells via the AMPK/ULK1 signaling pathway.

The Protective Impact of Salsola imbricata Leaf Extract From Taif Against Acrylamide-Induced Hepatic Inflammation and Oxidative Damage: The Role of Antioxidants, Cytokines, and Apoptosis-Associated Genes

Salsola imbricata is a herbal plant native to Saudi Arabia, known for its antioxidative and anti-inflammatory properties. This study explored the protective effects of an ethanolic leaf extract of Salsola imbricata against the oxidative stress and hepatic injury caused by acrylamide. Rats received intragastric administrations of 20 mg/kg of body weight of acrylamide to induce hepatic injury, or 300 mg/kg of body weight of Salsola ethanolic extract orally for 7 days before acrylamide administration. The treatments were continued for 3 weeks. Blood and liver samples were collected from all the groups, and the following biochemical parameters were tested: serum ALT (alanine aminotransferase), AST (aspartate aminotransferase), GGT (gamma glutaryl transferase), urea, albumin, total proteins, catalase, SOD (superoxide dismutase), reduced glutathione (GSH), nitric oxide (NO), and MDA (malondialdehyde). Quantitative real-time PCR (qRT-PCR) was used to examine the expression of Nrf2 (Nuclear factor-erythroid factor 2-related factor 2), HO-1 (Hemoxygenase-1), COX-2 (Cyclooxgenase-2), TGF-β1 (transforming growth factor-beta1), Bax, and Bcl2 (B-cell lymphoma 2), which are associated with oxidative stress, fibrosis, apoptosis, and anti-apoptotic effects. The annexin and survivin immunoreactivity were examined at the immunohistochemical level. Pretreatment with the Salsola ethanolic extract reduced the negative impact of acrylamide on ALT, AST, GGT, urea, albumin, and total proteins. The Salsola ethanolic extract reversed acrylamide's effects on serum and tissue antioxidants. Nrf2/HO-1 expression was downregulated, while COX-2 and TGF-β1 were upregulated in the acrylamide-administered group and normalized by the pre-administration of Salsola ethanolic extract to the acrylamide experimental group. The immunoreactivity of annexin and survivin was restored in the experimental group administered Salsola ethanolic extract plus acrylamide. In conclusion, Salsola ethanolic extract inhibits and regulates the side effects induced in the liver by acrylamide. Salsola induced its impacts by regulating inflammation, oxidative stress, and apoptosis-/anti-apoptosis-associated genes at the biochemical, molecular, and cellular levels. Salsola is recommended as oxidative stress relievers against environmental toixicity at high altitude areas.