Natural antioxidants' effects on endoplasmic reticulum stress-related diseases

Neuroprotective Effects of Lilium Lancifolium Thunberg Extract Against Corticosterone-Induced Dysfunctions in PC12 Cells

Chronic stress in the central nervous system can lead to neurological dysfunction characterized by spontaneous neuronal cell death. This study investigated the neuroprotective potential of an aqueous extract of Lilium lancifolium Thunberg (ELL) against corticosterone (CORT)-induced pathophysiology in PC12 cells. To assess the neuroprotective effects of ELL, PC12 cells were pretreated with 50 µg/mL of ELL before being exposed to CORT. ELL significantly prevented CORT-induced neuronal cell death by attenuating pro-apoptotic protein expression, lactate dehydrogenase release, and reactive oxygen species generation, while maintaining intact adenosine triphosphate levels. Furthermore, ELL significantly mitigated CORT-induced endoplasmic reticulum (ER) stress responses by attenuating the elevation of unfolded protein responses, intracellular calcium levels, opening of mitochondrial permeability transition pores, and loss of mitochondrial membrane potential. In conclusion, ELL exerts neuroprotective effects by inhibiting apoptosis through the mitigation of CORT-induced ER stress and mitochondrial dysfunction, suggesting that ELL may prevent neuronal damage associated with chronic stress-induced neurotoxicity.

Multi-Targeting Phytochemicals for Alzheimer's Disease

Alzheimer's disease (AD) is a type of neurodegenerative illness in which β-amyloid (Aβ) and tau protein accumulate in neurons in the form of tangles. The pathophysiological pathway of AD consists of Aβ-amyloid peptides, tau proteins, and oxidative stress in neurons and increased neuro-inflammatory response. Food and Drug Administration in the United States has authorized various drugs for the effective treatment of AD, which include galantamine, rivastigmine, donepezil, memantine, sodium oligomannate, lecanemab, and aducanumab. The major disadvantage of these drugs is that they only provide "symptomatic" relief. They are most effective in the early stages or for mild to moderate cases of the disease, but are not suitable for long-term use. Besides conventional therapies, phytochemicals have the potential to stop the progression of AD. According to research, the use of potential phytochemicals against AD has gained attention due to their potent anti-inflammatory, antioxidant, anti-hyperphosphorylation of the tau protein, metal chelation, and anti-amyloid properties. This study seeks to provide an up-to-date compilation of the most current and promising breakthroughs in AD therapy using phytochemicals. It could be concluded that phytochemicals light serve as an effective therapy for AD. However, more mechanistic investigations are needed to determine the clinical implications of phytochemicals in AD treatment.

A review on endoplasmic reticulum-dependent anti-breast cancer activity of herbal drugs: possible challenges and opportunities

Breast cancer (BC) is a major cause of cancer-related mortality across the globe and is especially highly prevalent in females. Based on the poor outcomes and several limitations of present management approaches in BC, there is an urgent need to focus and explore an alternate target and possible drug candidates against the target in the management of BC. The accumulation of misfolded proteins and subsequent activation of unfolded protein response (UPR) alters the homeostasis of endoplasmic reticulum (ER) lumen that ultimately causes oxidative stress in ER. The UPR activates stress-detecting proteins such as IRE1α, PERK, and ATF6, these proteins sometimes may lead to the activation of pro-apoptotic signaling pathways in cancerous cells. The ER stress-dependent antitumor activity could be achieved either through suppressing the adaptive UPR to make cells susceptible to ER stress or by causing chronic ER stress that may lead to triggering of pro-apoptotic signaling pathways. Several herbal drugs trigger ER-dependent apoptosis in BC cells. Therefore, this review discussed the role of fifty-two herbal drugs and their active constituents, focusing on disrupting the balance of the ER within cancer cells. Further, several challenges and opportunities have also been discussed in ER-dependent management in BC.Breast cancer (BC) is a major cause of cancer-related mortality across the globe and is especially highly prevalent in females. Based on the poor outcomes and several limitations of present management approaches in BC, there is an urgent need to focus and explore an alternate target and possible drug candidates against the target in the management of BC. The accumulation of misfolded proteins and subsequent activation of unfolded protein response (UPR) alters the homeostasis of endoplasmic reticulum (ER) lumen that ultimately causes oxidative stress in ER. The UPR activates stress-detecting proteins such as IRE1α, PERK, and ATF6, these proteins sometimes may lead to the activation of pro-apoptotic signaling pathways in cancerous cells. The ER stress-dependent antitumor activity could be achieved either through suppressing the adaptive UPR to make cells susceptible to ER stress or by causing chronic ER stress that may lead to triggering of pro-apoptotic signaling pathways. Several herbal drugs trigger ER-dependent apoptosis in BC cells. Therefore, this review discussed the role of fifty-two herbal drugs and their active constituents, focusing on disrupting the balance of the ER within cancer cells. Further, several challenges and opportunities have also been discussed in ER-dependent management in BC.

Sigma-1 receptor exerts protective effects on ameliorating nephrolithiasis by modulating endoplasmic reticulum-mitochondrion association and inhibiting endoplasmic reticulum stress-induced apoptosis in renal tubular epithelial cells

Oxalate-induced damage to renal tubular epithelial cells (RTECs) is an essential factor in the incident kidney stone, but the specific mechanism is unclear. Recent research has pinpointed interacting areas within the endoplasmic reticulum and mitochondria, called mitochondria-associated membranes (MAMs). These studies have linked endoplasmic reticulum stress (ERS) and oxidative imbalance to kidney disease development. The sigma-1 receptor (S1R), a specific protein found in MAMs, is involved in various physiological processes, but its role in oxalate-induced kidney stone formation remains unclear. In this study, we established cellular and rat models of oxalate-induced kidney stone formation to elucidate the S1R's effects against ERS and apoptosis and its mechanism in oxalate-induced RTEC injury. We found that oxalate downregulated S1R expression in RTECs and escalated oxidative stress and ERS, culminating in increased apoptosis. The S1R agonist dimemorfan up-regulated S1R expression and mitigated ERS and oxidative stress, thereby reducing apoptosis. This protective effect was mediated through S1R inhibition of the CHOP pathway. Animal experiments demonstrated that S1R's activation attenuated oxalate-induced kidney injury and alleviated kidney stone formation. This is the first study to establish the connection between S1R and kidney stones, suggesting S1R's protective role in inhibiting ERS-mediated apoptosis to ameliorate kidney stone formation.

Octanoic Acid and Decanoic Acid Inhibit Tunicamycin-Induced ER Stress in Rat Aortic Smooth Muscle Cells

ER stress is a crucial factor in the progression of vascular cell diseases. Notably, octanoic acid (OA; C8:0) and decanoic acid (DA; C10:0), prominent components of medium-chain fatty acids (MCFAs), may provide potential health benefits. However, their effects on vascular smooth muscle cells (VSMCs) remain unknown. Given the link between ER stress and vascular cell pathological conditions, the primary goal of this research is to investigate the protective effects of OA and DA against ER stress induction in rat aortic smooth muscle cells (RASMCs). To achieve this objective, RASMCs were pretreated with OA and DA at concentrations of 250 and 500 μM for 24 h. Subsequently, the cells were exposed to 1 μg/mL of tunicamycin, an ER stress inducer, for an additional 24 h. Apoptosis was assessed using DAPI staining, while DCFH2-DA probe was used to measure ROS levels. Furthermore, the gene expression of ER stress markers, such as CHOP, GRP78, ATF4, and eIF2α, as well as contractile markers like αSMA and MYH11, was assessed using real-time reverse transcription polymerase chain reaction. Moreover, the αSMA protein level was measured using immunocytochemistry techniques. The study revealed that OA and DA significantly mitigated cell death caused by tunicamycin, decreased ROS production, and inhibited the gene expression of ER stress markers (CHOP, GRP78, and eIF2α). Notably, OA and DA also inhibited the expression of contractile genes (α-SMA and MYH11) and reduced the number of α-SMA-positive cells in tunicamycin-treated RASMCs. These findings indicate that OA and DA offer protection against ER stress-stimulated cell death and ROS generation in VSMCs, thereby supporting their potential therapeutic applications for safeguarding these cells.

The protective role of selenium against high-fructose corn syrup-induced kidney damage: a histopathological and molecular analysis

With the growth of the food industry, fructose, the intake of which increases with food, causes obesity and metabolic syndrome. Kidney damage may develop from metabolic syndrome. Selenium (Se) participates in the structure of antioxidant enzymes and has a medicinal effect. In this work, the protective impact of Se on kidney damage produced by high-fructose corn syrup (HFCS) via endoplasmic reticulum (ER) stress was examined. The study comprised four groups, each consisting of ten experimental animals: control, HFCS (20%-HFCS), HFCS (20%-HFCS), + Se (0.3 mg/kg/day/po), and Se (0.3 mg/kg/day/po) alone. The duration of the experiment was 6 weeks. Kidney tissues were stained with hematoxylin and eosin for histological examination. Immunohistochemical analysis was conducted to assess TNF-α and caspase-3 levels. The spectrophotometric evaluation was performed to measure TOS (total oxidant status), TAS (total antioxidant status), and OSI (oxidative stress index) levels. The PERK, ATF4, CHOP, BCL-2, and caspase-9 gene expression levels were assessed by the RT-qPCR method. After Se treatment, histopathological abnormalities and TNF-α and caspase-3 levels in the HFCS+Se group decreased (p < 0.001). While TOS and OSI levels increased dramatically in the HFCS group, TAS values decreased significantly but improved after Se application (p < 0.001). The expression levels of the genes PERK, ATF4, CHOP, and caspase-9 were significantly lower in the HFCS group when compared to the HFCS+Se group (p < 0.05). Our findings suggest that Se may protect against ER stress, oxidative stress, apoptosis, and kidney damage caused by high-dose fructose consumption.

Usnic acid alleviates testicular ischemia/reperfusion injury in rats by modulating endoplasmic reticulum stress

Testicular torsion (TT) is a urological condition that can result in infertility in men. The etiopathogenesis of TT includes ischemia/reperfusion injury (IRI) characterized by oxidative stress (OS), inflammation and apoptosis resulting from increased levels of free radicals. Usnic acid (UA), a dibenzofuran, is one of the most common metabolites found in lichens and is known to possess powerful antioxidant properties. The aim of this study was to investigate the potential protective activity of UA in an experimental testicular IRI model for the first time. A total of 18 rats were randomly assigned to three groups (n=6): sham control, IRI and IRI+UA. The IRI groups underwent a four-hour period of ischemia and a two-hour period of reperfusion. The OS, inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in testicular tissue were evaluated using colorimetric methods. Furthermore, tissue samples were subjected to histological examination, with staining using hematoxylin and eosin. Histopathological findings supported by increased OS, inflammation, ERS and apoptosis levels were obtained in IRI group compared with sham control group. However, UA treatment restored these pathological and biochemical changes. Although this study provides the first preliminary evidence that UA may be used as a useful molecule against testicular IRI, further extensive molecular preclinical studies should be performed before clinical use is considered.

Gentisic acid attenuates 5-fluorouracil-induced ovotoxicity in rats via modulating Nrf2 signalling: An experimental approach

5-Fluorouracil (5-FU) is the third most used chemotherapeutic in the world with its anticancer effect resulting from its potential to block DNA replication. Like other cytotoxic agents, 5-FU has side effects on healthy tissues, and the reproductive system is among the tissues most affected by these undesirable effects. Gentisic acid (GEA) is a secondary metabolite that is abundant in fruits, vegetables and spices and has antioxidant activity. This study was conducted to investigate the toxicity of 5-FU in rat ovarian tissue and to determine the therapeutic activity of GEA on ovotoxicity caused by 5-FU. The results showed that 5-FU caused histopathological findings by suppressing Nrf2 pathway and accordingly increasing oxidative stress, inflammation, endoplasmic reticulum stress and apoptosis. However, GEA treatments after 5-FU application ameliorated 5-FU-induced ovotoxicity dose-dependently through activation of Nrf2 pathway. All these findings provided strong evidence supporting the hypothesis that GEA treatment may have therapeutic effects against 5-FU-induced ovarian damage. However, the beneficial effect of GEA use in eliminating ovarian damage in women after 5-FU chemotherapy should continue to be investigated with more detailed molecular studies.

The detrimental role of galectin-3 and endoplasmic reticulum stress in the cardiac consequences of myocardial ischemia in the context of obesity

The association between cardiac fibrosis and galectin-3 was evaluated in patients with acute myocardial infarction (MI). The role of galectin-3 and its association with endoplasmic reticulum (ER) stress activation in the progression of cardiovascular fibrosis was also evaluated in obese-infarcted rats. The inhibitor of galectin-3 activity, modified citrus pectin (MCP; 100 mg/kg/day), and the inhibitor of the ER stress activation, 4-phenylbutyric acid (4-PBA; 500 mg/kg/day), were administered for 4 weeks after MI in obese rats. Overweight-obese patients who suffered a first MI showed higher circulating galectin-3 levels, higher extracellular volume, and LV infarcted size, as well as lower E/e'ratio and LVEF compared with normal-weight patients. A correlation was observed between galectin-3 levels and extracellular volume. Obese-infarcted animals presented cardiac hypertrophy and reduction in LVEF, and E/A ratio as compared with control animals. They also showed an increase in galectin-3 gene expression, as well as cardiac fibrosis and reduced autophagic flux. These alterations were associated with ER stress activation characterized by enhanced cardiac levels of binding immunoglobulin protein, which were correlated with those of galectin-3. Both MCP and 4-PBA not only reduced cardiac fibrosis, oxidative stress, galectin-3 levels, and ER stress activation, but also prevented cardiac functional alterations and ameliorated autophagic flux. These results show the relevant role of galectin-3 in the development of diffuse fibrosis associated with MI in the context of obesity in both the animal model and patients. Galectin-3 in tandem with ER stress activation could modulate different downstream mechanisms, including inflammation, oxidative stress, and autophagy.

Protective roles of thrombomodulin in cisplatin-induced nephrotoxicity through the inhibition of oxidative and endoplasmic reticulum stress

Cisplatin is an effective chemotherapeutic agent widely used for the treatment of various solid tumors. However, cisplatin has an important limitation in its use; currently, there is no method to ameliorate cisplatin-induced acute kidney injury (AKI). Thrombomodulin (TM) is well known not only for its role as a cofactor in the clinically important natural anticoagulation pathway but also for its anti-inflammatory properties. Here, we investigated the effects of TM in cisplatin-induced AKI. In mice intraperitoneally injected with 15 mg/kg cisplatin, TM (10 mg/kg) or PBS was administered intravenously at 24 h after cisplatin injection. TM significantly attenuated cisplatin-induced nephrotoxicity with the suppressed elevation of blood urea nitrogen and serum creatinine, and reduced histological damages. Actually, TM treatment significantly alleviated oxidative stress-induced apoptosis by reducing reactive oxygen species (ROS) levels in cisplatin-treated renal proximal tubular epithelial cells (RPTECs) in vitro. Furthermore, TM clarified cisplatin-induced apoptosis by reducing caspase-3 levels. In addition, TM attenuated the endoplasmic reticulum (ER) stress signaling pathway in both renal tissues and RPTECs to protect the kidneys from cisplatin-induced AKI. These findings suggest that TM is a potential protectant against cisplatin-induced nephrotoxicity through suppressing ROS generation and ER stress in response to cisplatin.

Impact of Air-Drying Temperatures on Drying Kinetics, Physicochemical Properties, and Bioactive Profile of Ginger

Ginger (Zingiber officinale Roscoe) is a perishable commodity that requires proper processing to maintain its bioactivity. This study evaluated the effect of different air-drying temperatures (50 °C, 60 °C, and 70 °C) on ginger's drying kinetics and quality attributes. For an enhanced understanding of the drying kinetics, we employed a detailed approach by combining an existing drying model (namely, Midilli) with the Arrhenius model. This combined model facilitates a thorough analysis of how temperature and time concurrently affect the moisture ratio, offering more profound insights into the drying mechanism. A higher drying rate was achieved at 70 °C, yet elevated drying temperatures could compromise the quality attributes of ginger slices. Ginger slices dried at 50 °C displayed improved physicochemical properties and less color browning. The evaluation of the bioactivity profile of resultant ginger extracts also revealed higher total phenolic contents (1875.87 ± 31.40 mg GAE/100 g) and DPPH radical scavenging activity (18.2 ± 0.9 mg TE/kg) in 50 °C treated ginger samples. Meanwhile, the hydroethanolic mixture (70% ethanol) was also reorganized with better extraction efficiency than water and MWF (a ternary blend of methanol, water, and formic acid) solution. The promising outcomes of this study endorse the influence of drying temperature on the quality characteristics and bioactive profile of ginger and the selection of suitable extraction solvents to acquire phenolic-rich extract.

Dietary conjugated linoleic acid downregulates the AlCl3-induced hyperactivation of compensatory and maladaptive signalling in the mouse brain cortex

Oxidative stress, hyperactivation of compensatory mechanisms (unfolded protein response, UPR; nuclear factor erythroid 2-related factor 2, Nrf2) and the stimulation of maladaptive response (inflammation/apoptosis) are interconnected pathogenic processes occurring during Alzheimer's disease (AD) progression. The neuroprotective ability of dietary Conjugated linoleic acid (CLAmix) in a mouse model of AlCl3-induced AD was recently described but, the effects of AlCl3 or CLAmix intake on these pathogenic processes are still unknown. The effects of dietary AlCl3 or CLAmix - alone and in combination - were examined in the brain cortex of twenty-eight BalbC mice divided into 4 groups (n = 7 each). The neurotoxic effects of AlCl3 were investigated in animals treated for 5 weeks with 100 mg/kg/day (AL). CLAmix supplementation (600 mg/kg bw/day) for 7 weeks (CLA) was aimed at evaluating its modulatory effects on the Nrf2 pathway while its co-treatment with AlCl3 during the last 5 weeks of CLAmix intake (CLA + AL) was used to investigate its neuroprotective ability. Untreated mice were used as controls. In the CLA group, the NADPH oxidase (NOX) activation in the brain cortex was accompanied by the modulation of the Nrf2 pathway. By contrast, in the AL mice, the significant upregulation of oxidative stress markers, compensatory pathways (UPR/Nrf2), proinflammatory cytokines (IL-6, TNFα) and the proapoptotic protein Bax levels were found as compared with control. Notably, in CLA + AL mice, the marked decrease of oxidative stress, UPR/Nrf2 markers and proinflammatory cytokines levels were associated with the significant increase of the antiapoptotic protein Bcl2. The involvement of NOX in the adaptive response elicited by CLAmix along with its protective effects against the onset of several pathogenic processes triggered by AlCl3, broadens the knowledge of the mechanism underlying the pleiotropic activity of Nrf2 activators and sheds new light on their potential therapeutic use against neurodegenerative disorders.

Isoliquiritigenin pretreatment regulates ER stress and attenuates cisplatin-induced nephrotoxicity in male Wistar rats

Cisplatin (CP) is a chemotherapeutic drug used to treat solid tumors. However, studies have revealed its nephrotoxic effect. Oxidative stress, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction are involved in CP-induced renal damage. Thus, preconditioning (hormetic effect) of ER stress is a strategy to prevent CP-induced renal damage. On the other hand, isoliquiritigenin (IsoLQ) is recognized as a flavonoid with antioxidant properties and an inducer of ER stress. Therefore, we evaluated the ER stress-inducing capacity of IsoLQ and its possible protective effect against CP-induced nephrotoxicity in adult male Wistar rats. The findings reflected that IsoLQ pretreatment might decrease renal damage by reducing plasma creatinine and blood urea nitrogen levels in animals with CP-induced nephrotoxicity. These may be associated with IsoLQ activating ER stress and unfolded protein response (UPR). We found increased messenger RNA levels of the ER stress marker glucose-related protein 78 kDa (GRP78). In addition, we also found that pretreatment with IsoLQ reduced the levels of CCAAT/enhancer-binding protein-homologous protein (CHOP) and X-box-binding protein 1 (XBP1) in the renal cortex, reflecting that IsoLQ can regulate the UPR and activation of the apoptotic pathway. Moreover, this preconditioning with IsoLQ of ER stress had oxidative stress-regulatory effects, as it restored the activity of glutathione peroxidase and glutathione reductase enzymes. Finally, IsoLQ modifies the protein expression of mitofusin 2 (Mfn-2) and voltage-dependent anion channel (VDAC). In conclusion, these data suggest that IsoLQ pretreatment has a nephroprotective effect; it could functionally regulate the ER and mitochondria and reduce CP-induced renal damage by attenuating hormesis-mediated ER stress.

Punicalagin relieves lipotoxic injuries on pancreatic β-cells via regulating the oxidative stress and endoplasmic reticulum stress-mediated apoptosis

Cellular toxicity of hyperlipidemia has been long considered a major cause of various intractable disease such as diabetes. Discovering lipotoxicity antagonist with high efficiency and low side effects is of importance to develop therapeutics for relevant diseases. In the current study, we evaluate the anti-lipotoxic potential of punicalagin (PU) on pancreatic cells and investigate its underpinning mechanism involved. The administration of PU effectively improved cell viability, quenched intracellular reactive oxygen species, alleviated lipid peroxidation, and enhanced cellular antioxidative capacity in RINm5F cells stimulated by sodium palmitate. Besides that, PU treatment significantly inhibited the overload of mitochondrial calcium ions; alleviated the activation of endoplasmic reticulum (ER) stress mediators including glucose-regulated protein 78, protein kinase RNA-like ER kinase, eukaryotic initiation factor 2α, activating transcription factor 6, caspase 12, and C/EBP homologous protein (CHOP); and attenuated the expression of cleaved caspase 3 and poly ADP-ribose polymerase in test cells. Further RNA interference experiment results and miR211-5p expression analysis revealed that PU may directly mitigate CHOP expression and upregulate the expression of miR211-5p to reduce ER stress-induced pancreatic cell death. The efficacy of PU in maintaining redox equilibrium and diminishing ER stress on pancreatic cells stressed by hyperlipidemia suggests that PU can be used as a promising dietary natural product to safeguard the pancreatic health against lipotoxicity.

SIK2 protects against renal tubular injury and the progression of diabetic kidney disease

Despite optimal medical therapy, many patients with diabetic kidney disease (DKD) progress to end-stage renal disease. The identification of new biomarkers and drug targets for DKD is required for the development of more effective therapies. The apoptosis of renal tubular epithelial cells is a key feature of the pathogenicity associated with DKD. SIK2, a salt-inducible kinase, regulates important biological processes, such as energy metabolism, cell cycle progression and cellular apoptosis. In our current study, a notable decrease in the expression of SIK2 was detected in the renal tubules of DKD patients and murine models. Functional experiments demonstrated that deficiency or inactivity of SIK2 aggravates tubular injury and interstitial fibrosis in diabetic mice. Based on transcriptome sequencing, molecular mechanism exploration revealed that SIK2 overexpression reduces endoplasmic reticulum (ER) stress-mediated tubular epithelial apoptosis by inhibiting the histone acetyltransferase activity of p300 to activate HSF1/Hsp70. Furthermore, the specific restoration of SIK2 in tubules blunts tubular and interstitial impairments in diabetic and vancomycin-induced kidney disease mice. Together, these findings indicate that SIK2 protects against renal tubular injury and the progression of kidney disease, and make a compelling case for targeting SIK2 for therapy in DKD.

Manganese-induced neuronal apoptosis: new insights into the role of endoplasmic reticulum stress in regulating autophagy-related proteins

Manganese (Mn) is an essential trace element that participates in various physiological and pathological processes. However, epidemiological observations indicate that overexposure to Mn is strongly associated with neurodegenerative disorders and has been recognized as a potential risk factor of neuronal apoptosis. Many mechanisms are involved in the pathogenesis of Mn-induced neuronal apoptosis, such as reactive oxygen species generation, neuroinflammation reactions, protein accumulation, endoplasmic reticulum stress (ER stress), and autophagy, all of which collectively accelerate the process of nerve cell damage. As sophisticated cellular processes for maintaining intracellular homeostasis, ER-mediated unfolded protein response and autophagy both play bilateral roles including cell protection and cell injury under pathophysiological conditions, which might interact with each other. Although emerging evidence suggests that ER stress is involved in regulating the compensatory activation of autophagy to promote cell survival, the inherent relationship between ER stress and autophagy on Mn-induced neurotoxicity remains obscure. Here, our review focuses on discussing the existing mechanisms and connections between ER stress, autophagy, and apoptosis, which provide a new perspective on Mn-induced neuronal apoptosis, and the pathogenesis of neurodegenerative diseases.

Syringic acid ameliorates ischemia/reperfusion-induced testicular injury in rats via suppressing of HMGB1/NF-κB axis and endoplasmic reticulum stress

PURPOSE

To investigate the possible protective role of syringic acid on torsion/detorsion-induced testicular injury using biochemical and histopathological approaches for the first time.

METHODS

A total of 24 rats were divided into 4 groups: sham control, torsion/detorsion, torsion/detorsion + syringic acid (50 mg/kg and 100 mg/kg). Tissue malondialdehyde, total oxidant status and total antioxidant status levels were determined using colorimetric methods. Tissue 8-hydroxy-2'-deoxyguanosine, superoxide dismutase, catalase, high mobility group box 1, nuclear factor kappa B protein 65, tumor necrosis factor-alpha, interleukin-6, myeloperoxidase, 78-kDa glucose-regulated protein, activating transcription factor-6, C/EBP homologous protein and caspase-3 levels were determined using commercial enzyme-linked immunosorbent assay kits. Johnsen's testicle scoring system was used for histological evaluation.

RESULTS

Compared with the control group, the levels of oxidative stress, inflammation, endoplasmic reticulum stress and apoptosis were significantly increased in the torsion/detorsion group (p < 0.05). Syringic acid administrations statistically significantly restored these damage in a dose dependent manner (p < 0.05). Moreover, it was found that the results of histological examinations supported the biochemical results to a statistically significant extent.

CONCLUSION

The overall results suggest that syringic acid emerges as a potential compound for the treatment of testicular torsion and may be subject to clinical trials.

Antioxidants affect endoplasmic reticulum stress-related diseases

The endoplasmic reticulum (ER) is a complex multifunctional organelle that maintains cell homeostasis. Intrinsic and extrinsic factors alter ER functions, including the rate of protein folding that triggers the accumulation of misfolded proteins and alters homeostasis, thus generating stress in the ER, which activates the unfolded protein response (UPR) pathway to promote cell survival and restore their homeostasis; however, if the damage is not corrected, it could also trigger cell death. In addition, ER stress and oxidative stress are closely related because excessive production of reactive oxygen species (ROS), a well-known inducer of ER stress, promotes the accumulation of misfolded proteins; at the same time, the ER stress enhances ROS production, generating a pathological cycle. Furthermore, it has been described that the dysregulation of the UPR contributes to the progression of various diseases, so the use of compounds capable of regulating ER stress, such as antioxidants, has been used in several experimental models of diseases to alleviate the damage induced by the maladaptive signaling of the UPR, the mechanism of action of antioxidants generally is dose-dependent, and it is specific in each tissue and pathology, could decrease or enhance specific proteins of the UPR to have beneficial or detrimental effects.

Protective Effect of Natural Antioxidants on Reducing Cisplatin-Induced Nephrotoxicity

The clinical application of cisplatin is limited by its adverse events, of which nephrotoxicity is the most commonly observed. In a cisplatin-induced pathological response, oxidative stress is one of the upstream reactions which inflicts different degrees of damages to the intracellular material components. Reactive oxygen species (ROS) are also one of the early signaling molecules that subsequently undergo a series of pathological reactions, such as apoptosis and necrosis. This review summarizes the mechanism of intracellular ROS generation induced by cisplatin, mainly from the consumption of endogenous antioxidants, destruction of antioxidant enzymes, induction of mitochondrial crosstalk between the endoplasmic reticulum by ROS and Ca²⁺, and destruction of the cytochrome P450 (CYP) system in the endoplasmic reticulum, all of which result in excessive accumulation of intracellular ROS and oxidative stress. In addition, studies demonstrated that natural antioxidants can protect against the cisplatin-induced nephrotoxicity, by reducing or even eliminating excess free radicals and also affecting other nonredox pathways. Therefore, this review on the one hand provides theoretical support for the research and clinical application of natural antioxidants and on the other hand provides a new entry point for the detailed mechanism of cisplatin nephrotoxicity, which may lay a solid foundation for the future clinical use of cisplatin.

Multi-Target Mechanisms of Phytochemicals in Alzheimer’s Disease: Effects on Oxidative Stress, Neuroinflammation and Protein Aggregation

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by a tangle-shaped accumulation of beta-amyloid peptide fragments and Tau protein in brain neurons. The pathophysiological mechanism involves the presence of Aβ-amyloid peptide, Tau protein, oxidative stress, and an exacerbated neuro-inflammatory response. This review aims to offer an updated compendium of the most recent and promising advances in AD treatment through the administration of phytochemicals. The literature survey was carried out by electronic search in the following specialized databases PubMed/Medline, Embase, TRIP database, Google Scholar, Wiley, and Web of Science regarding published works that included molecular mechanisms and signaling pathways targeted by phytochemicals in various experimental models of Alzheimer’s disease in vitro and in vivo. The results of the studies showed that the use of phytochemicals against AD has gained relevance due to their antioxidant, anti-neuroinflammatory, anti-amyloid, and anti-hyperphosphorylation properties of Tau protein. Some bioactive compounds from plants have been shown to have the ability to prevent and stop the progression of Alzheimer’s.

Resolvin D1 Attenuates Doxorubicin-Induced Cardiotoxicity by Inhibiting Inflammation, Oxidative and Endoplasmic Reticulum Stress

Resolvin D1 (RvD1) is a lipid mediator that promotes resolution of inflammation. However, the function of RvD1 in doxorubicin- (Dox-) induced cardiotoxicity remains to be clarified. This study aimed to investigate whether RvD1 could attenuate Dox-induced cardiac injury. The mice were divided into three groups: control, Dox (20 mg/kg, once, intraperitoneally), and Dox + RvD1. RvD1 (2.5 μg/kg, intraperitoneally) was injected daily for 5 days. Echocardiography was performed to evaluate the cardiac function, and the heart tissue and serum samples were collected for further analyses. The results showed that RvD1 attenuated the decreased ratio of heart weight/body weight and heart weight/tibia length, the increased level of creatine kinase and activity of lactate dehydrogenase after Dox treatment. RvD1 improved the ejection fraction and fractional shortening of left ventricular and attenuated the severity of apoptosis induced by Dox. As for the underlying pathways, the results showed that RvD1 reduced the expression of IL-1 and IL-6, and attenuated the phosphorylation of P65 in cardiac tissue. RvD1 attenuated the oxidative stress induced by Dox, as demonstrated by the attenuated levels of superoxide dismutase, glutathione, and malondialdehyde, decreased expression of Nox-2 and Nox-4 and increased expression of Nrf-2 and HO-1. In addition, RvD1 also inhibited the endoplasmic reticulum stress induced by Dox. These results indicate the potential therapeutic benefits of RvD1 in Dox-induced cardiotoxicity in mice, and the mechanism may be related to the attenuated inflammation, oxidative stress and endoplasmic reticulum stress.

Arctigenin alleviates cadmium-induced nephrotoxicity: Targeting endoplasmic reticulum stress, Nrf2 signaling, and the associated inflammatory response

AIM

Nephrotoxicity is a critical consequence of cadmium toxicity. Cadmium induces nephrotoxicity through disruption of cellular redox balance and induction of endoplasmic reticulum stress (ERS) and inflammatory responses. The present study investigated the renoprotective effects of the naturally occurring arctigenin against the cadmium-induced nephrotoxicity.

MAIN METHODS

Male Wistar rats were randomized into normal control, arctigenin control, cadmium, and cadmium/arctigenin groups. Cadmium and arctigenin were administered daily over a seven-day period. On the eighth day, blood and kidney tissue specimens were collected and subjected to spectrophotometric, ELISA, and immunoblotting analysis.

KEY FINDINGS

Arctigenin significantly improved renal functions and reduced renal tubular injury in the cadmium-intoxicated rats as reflected by increased GFR and reduced levels of serum creatinine, BUN, urinary albumin-to-creatinine ratio, and protein expression of KIM-1. Arctigenin alleviated the cadmium-induced oxidative DNA damage and lipid peroxidation while boosted reduced glutathione level and antioxidant enzymes activity. Mechanistically, arctigenin enhanced nuclear translocation of the antioxidant transcription factor Nrf2 and up-regulated its downstream redox-regulating enzymes HO-1 and NQO1. Importantly, arctigenin ameliorated the cadmium-evoked ERS as demonstrated by reduced protein expression of the key molecules Bip, PERK, IRE1α, CHOP, phspho-eIF2α, and caspase-12 and diminished activity of caspase-12. Additionally, arctigenin down-regulated the cadmium-induced NF-κB nuclear translocation and decreased its downstream pro-inflammatory cytokines TNF-α and IL-1β.

SIGNIFICANCE

The current work underlines the alleviating activity of arctigenin against cadmium-evoked nephrotoxicity potentially through mitigating ERS and targeting Nrf2 and NF-κB signaling. The current findings support possible therapeutic application of arctigenin in controlling cadmium-induced nephrotoxicity although clinical investigations are necessary.

Artepillin C, a major component of Brazilian green propolis, inhibits endoplasmic reticulum stress and protein aggregation

Propolis, a compound produced by honeybees, has long been used in food and beverages to improve health and prevent diseases. We previously reported that the ethanol extracts of Brazilian green propolis and its constituents artepillin C, kaempferide, and kaempferol mitigate oxidative stress-induced cell death via oxytosis/ferroptosis. Here, we investigated the potential of Brazilian green propolis and its constituents to protect against endoplasmic reticulum stress in the mouse hippocampal cell line HT22. Ethanol extracts of Brazilian green propolis, artepillin C, and kaempferol attenuated tunicamycin-induced unfolded protein response and cell death. Interestingly, artepillin C inhibited both tunicamycin-induced protein aggregation in HT22 cells and the spontaneous protein aggregation of mutant canine superoxide dismutase 1 (E40K-SOD1-EGFP) in Neuro2a cells. These findings indicate that in addition to oxidative stress, the ethanol extracts of Brazilian green propolis help prevent endoplasmic reticulum stress-related neuronal cell death, which is proposedly involved in several neurodegenerative diseases. Moreover, artepillin C, a major constituent of Brazilian green propolis, may exhibit chemical chaperone-like properties.

Berberine-Albumin Nanoparticles: Preparation, Thermodynamic Study and Evaluation Their Protective Effects Against Oxidative Stress in Primary Neuronal Cells as a Model of Alzheimer's Disease

Berberine has shown an outstanding antioxidant activity, however the low bioavailability limits its applications in pharmaceutical platforms. Therefore, in this paper, after fabrication of the berberine-HSA nanoparticles by desolvation method, they were well characterized by TEM, SEM, DLS, and FTIR techniques. Afterwards the interaction of HSA and the berberine was evaluated by molecular docking analysis. Finally, the antioxidant activity of the berberine-HSA nanoparticles against H₂O₂-induced oxidative stress in cultured neurons as a model of AD was evaluated by cellular assays. The results showed that the prepared berberine-HSA nanoparticles have a spherical-shaped morphology with a size of around 100 nm and zeta potential value of -31.84 mV. The solubility value of nanoparticles was calculated to be 40.27%, with a berberine loading of 19.37%, berberine entrapment efficiency of 70.34%, and nanoparticles yield of 88.91%. Also, it was shown that the berberine is not significantly released from HSA nanoparticles within 24 hours. Afterwards, molecular docking investigation revealed that berberine spontaneously interacts with HSA through electrostatic interaction. Finally, cellular assays disclosed that the pretreatment of neuronal cultures with berberine-HSA nanoparticles decreased the H₂O₂-stimulated cytotoxicity and relevant morphological changes and enhanced the CAT activity. In conclusion, it can be indicated that the nanoformulation of the berberine can be used as a promising platform for inhibition of oxidative damage-induced Alzheimer's disease (AD).

Endoplasmic reticulum stress as the basis of obesity and metabolic diseases: focus on adipose tissue, liver, and pancreas

Obesity challenges lipid and carbohydrate metabolism. The resulting glucolipotoxicity  causes endoplasmic reticulum (ER) dysfunction, provoking the accumulation of immature proteins, which triggers the unfolded protein reaction (UPR) as an attempt to reestablish ER homeostasis. When the three branches of UPR fail to correct the unfolded/misfolded proteins, ER stress happens. Excessive dietary saturated fatty acids or fructose exhibit the same impact on the ER stress, induced by excessive ectopic fat accumulation or rising blood glucose levels, and meta-inflammation. These metabolic abnormalities can alleviate through dietary interventions. Many pathways are disrupted in adipose tissue, liver, and pancreas during ER stress, compromising browning and thermogenesis, favoring hepatic lipogenesis, and impairing glucose-stimulated insulin secretion within pancreatic beta cells. As a result, ER stress takes part in obesity, hepatic steatosis, and diabetes pathogenesis, arising as a potential target to treat or even prevent metabolic diseases. The scientific community seeks strategies to alleviate ER stress by avoiding inflammation, apoptosis, lipogenesis suppression, and insulin sensitivity augmentation through pharmacological and non-pharmacological interventions. This comprehensive review aimed to describe the contribution of excessive dietary fat or sugar to ER stress and the impact of this adverse cellular environment on adipose tissue, liver, and pancreas function.

A recent update on the multifaceted health benefits associated with ginger and its bioactive components

Due to recent lifestyle shifts and health discernments among consumers, synthetic drugs are facing the challenge of controlling disease development and progression. Various medicinal plants and their constituents are recognized for their imminent role in disease management via modulation of biological activities. At present, research scholars have diverted their attention on natural bioactive entities with health-boosting perception to combat the lifestyle-related disarrays. In particular, Zingiber officinale is a medicinal herb that has been commonly used in food and pharmaceutical products. Its detailed chemical composition and high value-added active components have been extensively studied. In this review, we have summarized the pharmacological potential of this well-endowed chemo preventive agent. It was revealed that its functionalities are attributed to several inherent chemical constituents, including 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 6-hydroshogaol, and oleoresin, which were established through many studies (in vitro, in vivo, and cell lines). In this review, we also focused on the therapeutic effects of ginger and its constituents for their effective antioxidant properties. Their consumption may reduce or delay the progression of related diseases, such as cancer, diabetes, and obesity, via modulation of genetic and metabolic activities. The updated data could elucidate the relationship of the extraction processes with the constituents and biological manifestations. We have collated the current knowledge (including the latest clinical data) about the bioactive compounds and bioactivities of ginger. Their detailed mechanisms, which can lay foundation for their food and medical applications are also discussed.

Sedum takesimense Protects PC12 Cells against Corticosterone-Induced Neurotoxicity by Inhibiting Neural Apoptosis

Neuronal cell death induced by chronic stress in the central nervous system is a cause of neurological dysfunction. We investigated the neuroprotective potential of a water extract of S. takesimense (WEST) against corticosterone-induced apoptosis in PC12 cells and the possible underlying mechanisms. Cells were pretreated with 50 µg/mL of WEST to evaluate its neuroprotective effect based on endoplasmic reticulum (ER) stress inhibition and mitochondrial function improvement. Pretreatment with WEST prevented corticosterone-induced injury in PC12 cells, resulting in increased cell survival, decreased lactate dehydrogenase (LDH) release, and potent apoptosis inhibition by a reduction in apoptotic nuclei demonstrated by Hoechst 33342 and propidium iodide (PI) double staining, and TUNEL staining. WEST strongly attenuated calcium (Ca²⁺) elevation, inducing the closure of mitochondrial permeability transition pores (mPTPs), which were opened by corticosterone. It also stabilized mitochondrial membrane potential (MMP) loss and inhibited the corticosterone-induced decrease in adenosine triphosphate (ATP) levels. Furthermore, the increased reactive oxygen species (ROS) production induced by corticosterone was prevented in PC12 cells treated with WEST. WEST also downregulated the expression of glucose-regulated protein 78 (GRP78), growth arrest- and DNA damage-inducible gene 153 (GADD153), the pro-apoptotic protein Bcl-2-associated X (Bax), cytochrome c, cysteine-aspartic protease (caspase)-9, and caspase-3, and upregulated the expression of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2). Thus, WEST exerts a neuroprotective effect by inhibiting the apoptosis pathway in ER stress and the mitochondrial dysfunction induced by corticosterone. These results demonstrate that WEST reduces neuronal damage from the neurotoxicity caused by chronic stress.

Dieckol, an algae-derived phenolic compound, suppresses airborne particulate matter-induced skin aging by inhibiting the expressions of pro-inflammatory cytokines and matrix metalloproteinases through regulating NF-κB, AP-1, and MAPKs signaling pathways

Exposure to particulate matter causes skin aging. In the present study, we investigated the effect of an algae-derived phenolic compound, dieckol (DK), against Chinese particulate matter (CPM)-stimulated aging in vitro in human dermal fibroblasts (HDF cells) and in vivo in zebrafish. DK effectively protected HDF cells against CPM-induced oxidative stress by scavenging intracellular reactive oxygen species. Moreover, DK significantly improved collagen synthesis and inhibited intracellular collagenase activity in CPM-stimulated HDF cells. In addition, DK remarkably reduced the expression of pro-inflammatory cytokines and matrix metalloproteinases via regulating the nuclear factor kappa B, activator protein 1, and mitogen-activated protein kinases signaling pathways in CPM-stimulated HDF cells. Furthermore, the in vivo test results demonstrated that DK effectively improved the survival rate of CPM-stimulated zebrafish via suppressing oxidative stress and inflammatory response. In conclusion, this study suggests that DK is a potential anti-aging compound that can be used as a therapeutic agent to improve CPM-induced skin aging, or as an ingredient to develop a cosmetic or medicine in the cosmeceutical and pharmaceutical industries.

Isoliquiritigenin Pretreatment Induces Endoplasmic Reticulum Stress-Mediated Hormesis and Attenuates Cisplatin-Induced Oxidative Stress and Damage in LLC-PK1 Cells

Isoliquiritigenin (IsoLQ) is a flavonoid with antioxidant properties and inducer of endoplasmic reticulum (ER) stress. In vitro and in vivo studies show that ER stress-mediated hormesis is cytoprotective; therefore, natural antioxidants and ER stress inducers have been used to prevent renal injury. Oxidative stress and ER stress are some of the mechanisms of damage involved in cisplatin (CP)-induced nephrotoxicity. This study aims to explore whether IsoLQ pretreatment induces ER stress and produces hormesis to protect against CP-induced nephrotoxicity in Lilly Laboratories Cell-Porcine Kidney 1 (LLC-PK1) cells. During the first stage of this study, both IsoLQ protective concentration and pretreatment time against CP-induced toxicity were determined by cell viability. At the second stage, the effect of IsoLQ pretreatment on cell viability, ER stress, and oxidative stress were evaluated. IsoLQ pretreatment in CP-treated cells induces expression of glucose-related proteins 78 and 94 kDa (GRP78 and GRP94, respectively), attenuates CP-induced cell death, decreases reactive oxygen species (ROS) production, and prevents the decrease in glutathione/glutathione disulfide (GSH/GSSG) ratio, free thiols levels, and glutathione reductase (GR) activity. These data suggest that IsoLQ pretreatment has a moderately protective effect on CP-induced toxicity in LLC-PK1 cells, through ER stress-mediated hormesis, as well as by the antioxidant properties of IsoLQ.

Melatonin inhibits oxalate-induced endoplasmic reticulum stress and apoptosis in HK-2 cells by activating the AMPK pathway

Background: Deposition of various crystal and organic substances in the kidney can lead to kidney stone formation. Melatonin is an effective endogenous antioxidant that can prevent crystalluria and kidney damage due to crystal formation and aggregation. In this study, we investigated the mechanism by which melatonin inhibits endoplasmic reticulum (ER) stress and apoptosis. Methods: We treated HK-2 cells with oxalate to establish an in vitro kidney stone model, and treated these cells with different concentrations of melatonin (0, 5, 10, 20 μmol/L) and the AMP-activated protein kinase (AMPK) inhibitor Compound C. We measured levels of stress response markers including reactive oxygen species (ROS), lactate dehydrogenase (LDH), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and factors in the stress response pathway, such as ATF6, GRP78, DDIT3, PERK, p-PERK, IRE1, p-IRE1, XBP1s, AMPK, and p-AMPK, using real time-PCR, western blot, and immunofluorescence analyzes. We measured mitochondrial membrane potential and caspases-3 activity using the CCK8, enzyme-linked immunosorbent, and flow cytometry assays to assess HK-2 cell viability and apoptosis. Results: Melatonin improved the total antioxidant capacity (T-AOC) of the HK-2 cells, as evidenced by the dose-dependent reduction in apoptosis, ROS levels, and protein expression of ATF6, GRP78, DDIT3, p-PERK, p-IRE1, XBP1s, caspase-12, cleaved caspase-3 and cleaved caspase-9. Addition of the AMPK inhibitor, Compound C, partially reversed the protective effect of melatonin. Conclusion: Our study revealed that the protective effects of melatonin on oxalate-induced ER stress and apoptosis is partly dependent on AMPK activation in HK-2 cells. These findings provide insight into the prevention and treatment of kidney stones.