Effect of long-term exposure to acrylamide on endoplasmic reticulum stress and autophagy in rat cerebellum

Effects of dietary acrylamide on kidney and liver health: Molecular mechanisms and pharmacological implications

Acrylamide (AA) has raised concerns throughout the world in recent years because of its potential negative effects on human health. Numerous researches on humans and animals have connected a high dietary exposure to AA to a possible risk of cancer. Additionally, higher consumption of acrylamide has also been associated with dysfunctioning of various organ systems from nervous system to the reproductive system. Acrylamide is primarily metabolised into the glycidamide inside the body which gets accumulated in different tissues including kidney and liver, and chronic exposure to this can lead to the nephrotoxicity and hepatotoxicity through different molecular mechanisms. This review summarizes the various sources, formation and metabolism of the dietary acrylamide along with the different molecular mechanisms such as oxidative stress, inflammation, DNA damage, autophagy, mitochondrial dysfunction and morphological changes in nephron and hepatocytes through which acrylamide exerts its deleterious effect on kidney and liver causing nephrotoxicity and hepatotoxicity. This review summarizes various animal and cellular studies that demonstrate AA-induced nephrotoxicity and hepatotoxicity. Lastly, the article emphasizes on underlying protective molecular mechanisms of various pharmacological interventions against acrylamide induced hepatotoxicity and nephrotoxicity.

Acrylamide Induces Antiapoptotic Autophagy and Apoptosis by Activating PERK Pathway in SH-SY5Y Cells

Acrylamide (ACR) is a commonly used organic compound that exhibits evident neurotoxicity in humans. Our previous studies showed that the mechanisms of ACR-caused neurotoxicity included apoptosis, PERK-mediated endoplasmic reticulum stress, and autophagy, but the relationships among them were still unclear. This paper investigated the relationships among apoptosis, autophagy, and the PERK pathway to demonstrate the mechanism of ACR neurotoxicity further. Different doses of ACR were set to value ACR toxicity. Then, a PERK inhibitor and autophagy inhibitor, GSK2606414 and 3-methyladenine (3-MA), were used separately to inhibit the PERK pathway and autophagy activation in SH-SY5Y cells under ACR treatment. With the increase of ACR dose, the apoptotic rate increased in a dose-dependent manner. After the inhibition of the PERK pathway, the activated apoptosis and autophagosome accumulation caused by ACR were alleviated. Under 3-MA and ACR treatment, the autophagy inhibition deteriorated apoptosis in SH-SY5Y cells but had no significant effect on ACR-induced PERK pathway activation; thus, PERK pathway-induced autophagy had an antiapoptotic role in this condition. This paper provides an experimental basis for exploring potential molecular targets to prevent and control ACR toxicity.

Attenuated neuronal differentiation caused by acrylamide is not related to oxidative stress in differentiated human neuroblastoma SH-SY5Y cells

Acrylamide (ACR) is a known neurotoxicant and developmental neurotoxicant. As a soft electrophile, ACR reacts with thiol groups in cysteine. One hypothesis of ACR induced neurotoxicity and developmental neurotoxicity (DNT) is conjugation with reduced glutathione (GSH) leading to GSH depletion, increased reactive oxygen species (ROS) production and further oxidative stress and cellular damage. In this regard, we have investigated the effect of ACR on neuronal differentiation, glutathione levels and ROS production in the human neuroblastoma SH-SY5Y cell model. After 9 days of differentiation and exposure, ACR significantly impaired area neurites per cell at non-cytotoxic concentrations (0.33 μM and 10 μM). Furthermore, 10 μM ACR dysregulated 9 mRNA markers important for neuronal development, 5 of them being associated with cytoskeleton organization and axonal guidance. At the non-cytotoxic concentrations that significantly attenuate neuronal differentiation, ACR did neither decrease the level of GSH or total glutathione levels, nor increased ROS production. In addition, the expression of 5 mRNA markers for cellular stress was assessed with no significant altered regulation after ACR exposure up to 320 μM. Thus, ACR-induced DNT is not due to GSH depletion and increased ROS production, neither at non-cytotoxic nor cytotoxic concentrations, in the SH-SH5Y model during differentiation.

Differential susceptibility of BRL cells with/without insulin resistance and the role of endoplasmic reticulum stress signaling pathway in response to acrylamide-exposure toxicity effects in vitro

Acrylamide (ACR) is an endogenous food contaminant, high levels of ACR have been detected in a large number of foods, causing widespread concern. Since different organism states respond differently to the toxic effects of pollutants, this study establishes an insulin-resistant BRL cell model to explore the differential susceptibility of BRL cells with/without insulin resistance in response to acrylamide-exposure (0.0002, 0.02, or 1 mM) toxicity effects and its mechanism. The results showed that ACR exposure decreased glucose uptake and increased intracellular lipid levels by promoting the expression of fatty acid synthesis, transport, and gluconeogenesis genes and inhibiting the expression of fatty acid metabolism genes, thereby further exacerbating disorders of gluconeogenesis and lipid metabolism in insulin-resistant BRL cells. Simultaneously, its exposure also exacerbated BRL cells with/without insulin-resistant damage. Meanwhile, insulin resistance significantly raised susceptibility to BRL cell response to ACR-induced toxicity. Furthermore, ACR exposure further activated the endoplasmic reticulum stress (ERS) signaling pathway (promoting phosphorylation of PERK, eIF-2α, and IRE-1α) and the apoptosis signaling pathway (activating Caspase-3 and increasing the Bax/Bcl-2 ratio) in BRL cells with insulin-resistant, which were also attenuated after ROS scavenging or ERS signaling pathway blockade. Overall results suggested that ACR evokes a severer toxicity effect on BRL cells with insulin resistance through the overactivation of the ERS signaling pathway.

Rosmarinic acid mitigates acrylamide induced neurotoxicity via suppressing endoplasmic reticulum stress and inflammation in mouse hippocampus

BACKGROUND

Acrylamide (ACR) is a widely used compound that is known to be neurotoxic to both experimental animals and humans, causing nerve damage. The widespread presence of ACR in the environment and food means that the toxic risk to human health can no longer be ignored. Rosmarinic acid (RA), a natural polyphenolic compound extracted from the perilla plant, exhibits anti-inflammatory, antioxidant, and other properties. It has also been demon strated to possess promising potential in neuroprotection. However, its role and potential mechanism in treating ACR induced neurotoxicity are still elusive.

PURPOSE

This study explores whether RA can improve ACR induced neurotoxicity and its possible mechanism.

METHODS

The behavioral method was used to study RA effect on ACR exposed mice's neurological function. We studied its potential mechanism through metabolomics, Nissl staining, HE staining, immunohistochemical analysis, and Western blot.

RESULTS

RA pretreatment reversed the increase in mouse landing foot splay and decrease in spontaneous activity caused by 3 weeks of exposure to 50 mg/kg/d ACR. Further experiments demonstrated that RA could prevent ACR induced neuronal apoptosis, significantly downregulate nuclear factor-κB and tumor necrosis factor-α expression, and inhibit NOD-like receptor protein 3 inflammasome activation, thereby reducing inflammation as confirmed by metabolomics results. Additionally, RA treatment prevented endoplasmic reticulum stress (ERS) caused by ACR exposure, as evidenced by the reversal of significant P-IRE1α,TRAF2,CHOP expression increase.

CONCLUSION

RA alleviates ACR induced neurotoxicity by inhibiting ERS and inflammation. These results provide a deeper understanding of the mechanism of ACR induced neurotoxicity and propose a potential new treatment method.

High-fat diet exacerbated motor dysfunction via necroptosis and neuroinflammation in acrylamide-induced neurotoxicity in mice

Health risks associated with acrylamide (ACR) or high-fat diet (HFD) exposure alone have been widely concerned in recent years. In a realistic situation, ACR and HFD are generally co-existence, and both are risk factors for the development of neurological diseases. The purpose of the present study was to investigate the combined effects of ACR and HFD on the motor nerve function. As a result, neurobehavioral tests and Nissl staining disclosed that long-term HFD exacerbated motor dysfunction and the damage of spinal cord motor neurons in ACR-exposed mice. Co-exposure of ACR and HFD resulted in morphological changes in neuronal mitochondria of the spinal cord, a significantly reduced mitochondrial subunits NDUFS1, UQCRC2, and MTCO1, released the mitochondrial DNA (mtDNA) into the cytoplasm, and promoted the production of reactive oxygen species (ROS). Combined exposure of HFD and ACR activated the calpain/CDK5/Drp1 axis and caused the mitochondrial excessive division, ultimately increasing MLKL-mediated necroptosis in spinal cord motor neurons. Meanwhile, HFD significantly exacerbated ACR-induced activation of NFkB, NLRP3 inflammasome, and cGAS-STING pathway. Taken together, our findings demonstrated that combined exposure of ACR and HFD aggravated the damage of spinal cord motor neurons via neuroinflammation and necroptosis signaling pathway, pointing to additive effects in mice than the individual stress effects.

Coenzyme Q10 attenuates neurodegeneration in the cerebellum induced by chronic exposure to tramadol

BACKGROUND

Chronic use of tramadol can cause neurotoxic effects and subsequently cause neurodegeneration in the cerebellum. The main damage mechanisms identified are oxidative stress and inflammation. Currently, we investigated the effects of coenzyme Q10 (CoQ10) in attenuates of neurodegeneration in the cerebellum induced by chronic exposure to tramadol.

MATERIAL AND METHODS

Seventy-two male mature albino rats were allocated into four equal groups, including; non-treated group, CoQ10 group (which received CoQ10 at 200 mg/kg/day orally for three weeks), tramadol group (which received tramadol hydrochloride at 50 mg/kg/day orally for three weeks), and tramadol+CoQ10 group (which received tramadol and CoQ10 at the same doses as the previous groups). Tissue samples were obtained for stereological, immunohistochemical, biochemical, and molecular evaluations. Also, functional tests were performed to evaluate behavioral properties.

RESULTS

We found a significant increase in stereological parameters, antioxidant factors (catalase, glutathione, and superoxide dismutase), and behavioral function scores in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05). In addition, malondialdehyde levels, the density of apoptotic cells, as well as the expression of pro-inflammatory (tumor necrosis factor-alpha, interleukin 1 beta, and interleukin 6) and autophagy (lysosome-associated membrane protein 2, autophagy-related 5, beclin 1, and autophagy-related 12) genes were considerably reduced in the tramadol+CoQ10 group compared to the tramadol group (p < 0.05).

CONCLUSION

We conclude that the administration of CoQ10 has neuroprotective effects in the cerebellum of rats that have chronic exposure to tramadol.

Research Progress of Programmed Cell Death Induced by Acrylamide

Acrylamide exposure through environment pollution and diet is very common in daily life. With the deepening of the study on the toxicity of acrylamide, it has attracted widespread attention for the effects of acrylamide on multiple organs through affecting a variety of programmed cell death. Multiple studies have shown that acrylamide could exert its toxic effect by inducing programmed cell death, but its specific molecular mechanism is still unclear. In this review, the research on the main forms of programmed cell death (apoptosis, autophagy, and programmed necrosis) induced by acrylamide and their possible mechanisms are reviewed. This review may provide basic data for further research of acrylamide and prevention of its toxicity.

Mitochondrial dysfunction promotes the necroptosis of Purkinje cells in the cerebellum of acrylamide-exposed rats

Acrylamide (ACR) is a common neurotoxicant that can induce central-peripheral neuropathy in human beings. ACR from occupational setting and foods poses a potential threat to people's health. Purkinje cells are the only efferent source of cerebellum, and their output is responsible for coordinating motor activity. Recent studies have reported that Purkinje cell injury is one of the earliest neurotoxicity at any dose rate of ACR. However, the mechanism underlying ACR-mediated damage to Purkinje cells remains unclear. This research aimed to investigate whether necroptosis is involved in ACR-induced Purkinje cell death and its regulatory mechanism. In this study, rats were treated with ACR (40 mg/kg/every other day) for 6 weeks to establish an animal model of ACR neuropathy. Furthermore, an intervention experiment was achieved by rapamycin (RAPA), which is commonly used to activate mitophagy and maintain mitochondrial homeostasis. The results demonstrated ACR exposure caused necroptosis of Purkinje cells, mitochondrial dysfunction, and inflammatory response. By contrast, RAPA alleviated mitochondrial dysfunction and inhibited activation of necroptosis signaling pathway following ACR. In conclusion, our findings suggest that mitochondrial dysfunction and activation of necroptotic signaling are associated with the loss of Purkinje cells in ACR poisoning, which can be a potential therapeutic target for ACR neurotoxicity.

Potential role of TGFΒ and autophagy in early crebellum development

During development, the interconnected generation of various neural cell types within the cerebellar primordium is essential. Over embryonic (E) days E9-E13, Purkinje cells (PCs), and cerebellar nuclei (CN) neurons are among the created primordial neurons. The molecular and cellular mechanisms fundamental for the early cerebellar neurogenesis, migration/differentiation, and connectivity are not clear yet. Autophagy has a vital role in controlling cellular phenotypes, such as epithelial-to-mesenchymal transition (EMT) and endothelial to mesenchymal transition (EndMT). Transforming growth factor-beta 1 (TGF-β1) is the main player in pre-and postnatal development and controlling cellular morphological type via various mechanisms, such as autophagy. Thus, we hypothesized that TGF-β1 may regulate early cerebellar development by modifying the levels of cell adhesion molecules (CAMs) and consequently autophagy pathway in the mouse cerebellar primordium. We demonstrated the stimulation of the canonical TGF-β1 signaling pathway at the point that concurs with the generation of the nuclear transitory zone and PC plate in mice. Furthermore, our data show that the stimulated TGF-β1 signaling pathway progressively and chronologically could upregulate the expression of β-catenin (CTNNB1) and N-cadherin (CDH2) with the most expression at E11 and E12, leading to upregulation of chromodomain helicase DNA binding protein 8 (CDH8) and neural cell adhesion molecule 1 (NCAM1) expression, at E12 and E13. Finally, we demonstrated that the stimulated TGF-β signaling pathway may impede the autophagic flux at E11/E12. Nevertheless, basal autophagy flux happens at earlier developmental phases from E9-E10. Our study determined potential role of the TGF-β signaling and its regulatory impacts on autophagic flux during cerebellar development and cadherin expression, which can facilitate the proliferation, migration/differentiation, and placement of PCs and the CN neurons in their designated areas.

Acrylamide Exposure Destroys the Distribution and Functions of Organelles in Mouse Oocytes

Acrylamide (ACR) is a common industrial ingredient which is also found in foods that are cooked at high temperatures. ACR has been shown to have multiple toxicities including reproductive toxicity. Previous studies reported that ACR caused oocyte maturation defects through the induction of apoptosis and oxidative stress. In the present study, we showed that ACR exposure affected oocyte organelle functions, which might be the reason for oocyte toxicity. We found that exposure to 5 mM ACR reduced oocyte maturation. ACR caused abnormal mitochondrial distribution away from spindle periphery and reduced mitochondrial membrane potential. Further analysis showed that ACR exposure reduced the fluorescence intensity of Rps3 and abnormal distribution of the endoplasmic reticulum, indicating that ACR affected protein synthesis and modification in mouse oocytes. We found the negative effects of ACR on the distribution of the Golgi apparatus; in addition, fluorescence intensity of vesicle transporter Rab8A decreased, suggesting the decrease in protein transport capacity of oocytes. Furthermore, the simultaneous increase in lysosomes and LAMP2 fluorescence intensity was also observed, suggesting that ACR affected protein degradation in oocytes. In conclusion, our results indicated that ACR exposure disrupted the distribution and functions of organelles, which further affected oocyte developmental competence in mice.