Biogenic Selenium Nanoparticles Alleviate Intestinal Epithelial Barrier Damage through Regulating Endoplasmic Reticulum Stress-Mediated Mitophagy

Review on the role of autophagy in the toxicity of nanoparticles and the signaling pathways involved

As the development of nanotechnology, the application of nanoproducts and the advancement of nanomedicine, the contact of nanoparticles (NPs) with human body is becoming increasingly prevalent. This escalation elevates the risk of NPs exposure for workers, consumers, researchers, and both aquatic and terrestrial organisms throughout the production, usage, and disposal stages. Consequently, evaluating nanotoxicity remains critically important, though standardized assessment criteria are still lacking. The diverse and complex properties of NPs further complicate the understanding of their toxicological mechanisms. Autophagy, a fundamental cellular process, exhibits dual functions-both pro-survival and pro-death. This review offers an updated perspective on the dual roles of autophagy in nanotoxicity and examines the factors influencing autophagic responses. However, no definitive framework exists for predicting NPs-induced autophagy. Beyond the conventional autophagy pathways, the review highlights specific transcription factors activated by NPs and explores metabolic reprogramming. Particular attention is given to NPs-induced selective autophagy, including mitophagy, ER-phagy, ferritinophagy, lysophagy, and lipophagy. Additionally, the review investigates autophagy's involvement in NPs-mediated biological processes such as ferroptosis, inflammation, macrophage polarization, epithelial-mesenchymal transition, tumor cell proliferation and drug resistance, as well as liver and kidney injury, neurotoxicity, and other diseases. In summary, this review presents a novel update on selective autophagy-mediated nanotoxicity and elucidates the broader interactions of autophagy in NPs-induced biological processes. Collectively, these insights offer valuable strategies for mitigating nanotoxicity through autophagy modulation and advancing the development of NPs in biomedical applications.

Selenium participates in the formation of kidney stones by alleviating endoplasmic reticulum stress and apoptosis of renal tubular epithelial cells

Objectives: To investigate the role of selenium and selenium-containing proteins in the etiology and pathogenesis of kidney stones.Methods: The HK-2 cell line was subjected to supersaturation oxalate treatment to establish an in vitro model of calcium oxalate kidney stones, while SD rats were administered with ethylene glycol to establish an in vivo model of calcium oxalate kidney stones. qPCR analysis was employed to investigate the alterations in selenoproteins within the models, and subsequently, genes exhibiting significant changes were identified. Subsequently, based on the functions of these genes, their regulatory effects on endoplasmic reticulum stress (ERS) and apoptosis during the disease progression were examined both in HK-2 cells and rat kidneys. Finally, Selenomethionine (SeMet) supplementation was introduced to explore its therapeutic potential for kidney stone management.Results: The involvement of Selenoprotein K in the pathogenesis of calcium oxalate kidney stone disease has been confirmed, exhibiting significant alterations. Manipulation of its expression levels through overexpression and knockdown techniques resulted in a corresponding reduction or increase in oxidative stress, ERS, and apoptosis within renal tubular epithelial cells. SelK regulates ERS and apoptosis by controlling the IRE1-ASK1-JNK pathway. In addition, SeMet treatment, which contains selenium, effectively reduced the levels of oxidative stress, ERS, and apoptosis in vivo and in vitro models, thereby alleviating tubular epithelial cell damage and reducing the formation of kidney stones in experimental rats.Discussion: Selenium is involved in the occurrence and development of kidney stones by regulating oxidative damage to renal tubular epithelial cells. The results suggest that dietary selenium supplementation in daily life may be of great significance for the prevention and treatment of kidney stones.

Mitophagy and its regulatory mechanisms in the biological effects of nanomaterials

Mitophagy is a selective cellular process critical for the removal of damaged mitochondria. It is essential in regulating mitochondrial number, ensuring mitochondrial functionality, and maintaining cellular equilibrium, ultimately influencing cell destiny. Numerous pathologies, such as neurodegenerative diseases, cardiovascular disorders, cancers, and various other conditions, are associated with mitochondrial dysfunctions. Thus, a detailed exploration of the regulatory mechanisms of mitophagy is pivotal for enhancing our understanding and for the discovery of novel preventive and therapeutic options for these diseases. Nanomaterials have become integral in biomedicine and various other sectors, offering advanced solutions for medical uses including biological imaging, drug delivery, and disease diagnostics and therapy. Mitophagy is vital in managing the cellular effects elicited by nanomaterials. This review provides a comprehensive analysis of the molecular mechanisms underpinning mitophagy, underscoring its significant influence on the biological responses of cells to nanomaterials. Nanoparticles can initiate mitophagy via various pathways, among which the PINK1-Parkin pathway is critical for cellular defense against nanomaterial-induced damage by promoting mitophagy. The role of mitophagy in biological effects was induced by nanomaterials, which are associated with alterations in Ca2+ levels, the production of reactive oxygen species, endoplasmic reticulum stress, and lysosomal damage.

Prophylactic supplementation with selenium nanoparticles protects against foodborne toxin zearalenone-induced intestinal barrier dysfunction

Selenium nanoparticles (SeNPs) have been used as a potential alternative to other forms of selenium in nutritional supplements for the treatment and prevention of inflammatory and oxidative stress-related diseases. Zearalenone (ZEA) is a foodborne mycotoxin present in grains that poses a health threat. Here, we investigated the adverse impacts of ZEA on intestinal homeostasis and explored the protective effects of probiotic-synthesized SeNPs against its damage. Results showed that ZEA reduced mucin and tight junction proteins expression in jejunum, induced inflammatory process and oxidative stress which in turn increased intestinal permeability in mice. ZEA-induced intestinal toxicity was further verified in vitro. Intracellular redox imbalance triggered endoplasmic reticulum (ER) stress in intestinal epithelial cells, which caused structural damage to the ER. Remarkably, SeNPs exhibited a counteractive effect by inducing a decrease in intracellular levels of Inositol 1,4,5-trisphosphate (IP3) and Ca2+, along with a reduction in the expression level of IP3 receptor. SeNPs effectively mitigated ZEA-induced ER stress was related to the increased activity of selenium-dependent antioxidant enzymes and the expression of ER-resident selenoproteins. Furthermore, SeNPs significantly inhibited the activation of PERK/eIF2α/ATF4/CHOP pathway in vitro and in vivo. In addition, SeNPs effectively reversed ZEA-induced gut microbiota dysbiosis and increased the abundance of short-chain fatty acid-producing beneficial bacteria (Alloprevotella and Muribaculaceae). The Spearman correlation analysis suggested that the structure of gut microbiota was closely related to the SeNPs attenuation of ZEA-induced intestinal toxicity. This study provides new insights into ZEA-induced intestinal toxicity and identifies a novel potential nutrient SeNPs to overcome adverse effects.

Endoplasmic reticulum stress: A possible connection between intestinal inflammation and neurodegenerative disorders

BACKGROUND

Different studies have shown the key role of endoplasmic reticulum (ER) stress in autoimmune and chronic inflammatory disorders, as well as in neurodegenerative diseases. ER stress leads to the formation of misfolded proteins which affect the secretion of different cell types that are crucial for the intestinal homeostasis.

PURPOSE

In this review, we discuss the role of ER stress and its involvement in the development of inflammatory bowel diseases, chronic conditions that can cause severe damage of the gastrointestinal tract, focusing on the alteration of Paneth cells and goblet cells (the principal secretory phenotypes of the intestinal epithelial cells). ER stress is also discussed in the context of neurodegenerative diseases, in which protein misfolding represents the signature mechanism. ER stress in the bowel and consequent accumulation of misfolded proteins might represent a bridge between bowel inflammation and neurodegeneration along the gut-to-brain axis, affecting intestinal epithelial homeostasis and the equilibrium of the commensal microbiota. Targeting intestinal ER stress could foster future studies for designing new biomarkers and new therapeutic approaches for neurodegenerative disorders.

Nano-Drug Delivery Systems Targeting CAFs: A Promising Treatment for Pancreatic Cancer

Currently, pancreatic cancer (PC) is one of the most lethal malignant tumors. PC is typically diagnosed at a late stage, exhibits a poor response to conventional treatment, and has a bleak prognosis. Unfortunately, PC's survival rate has not significantly improved since the 1960s. Cancer-associated fibroblasts (CAFs) are a key component of the pancreatic tumor microenvironment (TME). They play a vital role in maintaining the extracellular matrix and facilitating the intricate communication between cancer cells and infiltrated immune cells. Exploring therapeutic approaches targeting CAFs may reverse the current landscape of PC therapy. In recent years, nano-drug delivery systems have evolved rapidly and have been able to accurately target and precisely release drugs with little or no toxicity to the whole body. In this review, we will comprehensively discuss the origin, heterogeneity, potential targets, and recent advances in the nano-drug delivery system of CAFs in PC. We will also propose a novel integrated treatment regimen that utilizes a nano-drug delivery system to target CAFs in PC, combined with radiotherapy and immunotherapy. Additionally, we will address the challenges that this regimen currently faces.

Effect of Administration of Selenium Nanoparticles Synthesized Using Onion Extract on Biochemical and Inflammatory Parameters in Mice Fed with High-Fructose Diet: In Vivo and In Silico Analysis

Fructose consumption has increased globally and has been linked to obesity, insulin resistance, and diabetes. Selenium nanoparticles (SeNPs) can regulate glucose and lipid concentrations and have immunoregulatory properties. Four study groups (n = 7/group) of eight-week-old male mice (Balb/c) were formed for this investigation. One group received a standard diet (C), another standard diet plus SeNPs (C + SeNPs), a high fructose diet (F), and a group with a high fructose diet plus SeNPs (F + SeNPs). Weight, glucose, triglycerides, and cholesterol were evaluated. In the end, mice were sacrificed, blood samples were obtained to assess cytokine profile, and liver, kidney, and pancreas were removed for histological examination. The study was complemented with an in silico analysis where the CTD, STITCH, ToppGene Suite, ShinyGO 0.76.3 databases, and Cytoscape software were implemented. The results of in vivo analysis showed that SeNPs regulated biochemical parameters and showed anti-inflammatory effects by decreasing the concentrations of TNF-alpha, IL-1beta, and IFN-gamma and increasing IL-10. No damage was observed in the studied organs. In addition, SeNPs regulate oxidative stress, preserve cell organelles, and regulate metabolic pathways to avoid the adverse effects of fructose consumption, according to bioinformatics analysis. In conclusion, SeNPs protect against the undesirable effects of a diet rich in fructose.

Role of Autophagy and Pyroptosis in Intervertebral Disc Degeneration

Intervertebral disc degeneration is a chronic degenerative disease caused by the interaction of genetic and environmental factors, mainly manifested as lower back pain. At present, the diagnosis of intervertebral disc degeneration mainly relies on imaging. However, early intervertebral disc degeneration is usually insidious, and there is currently a lack of relevant clinical biomarkers that can reliably reflect early disease progression. Pyroptosis is a regulatory form of cell death triggered by the activation of inflammatory bodies and caspase, which can induce the formation of plasma membrane pores and cell swelling or lysis. Previous studies have shown that during the progression of intervertebral disc degeneration, sustained activation of inflammasomes leads to nuclear cell pyroptosis, which can occur in the early stages of intervertebral disc degeneration. Moreover, intervertebral disc nucleus pulposus cells adapt to the external environment through autophagy and maintain cellular homeostasis and studying the mechanism of autophagy in IDD and intervening in its pathological and physiological processes can provide new ideas for the clinical treatment of IDD. This review analyzes the effects of pyroptosis and autophagy on IDD by reviewing relevant literature in recent years, in order to explore the relationship between pyroptosis, autophagy and IDD.

New insights into the unfolded protein response (UPR)-anterior gradient 2 (AGR2) pathway in the regulation of intestinal barrier function in weaned piglets

Sustained dysfunction of the intestinal barrier caused by early weaning is a major factor that induces postweaning diarrhea in weaned piglets. In both healthy and diseased states, the intestinal barrier is regulated by goblet cells. Alterations in the characteristics of goblet cells are linked to intestinal barrier dysfunction and inflammatory conditions during pathogenic infections. In this review, we summarize the current understanding of the mechanisms of the unfolded protein response (UPR) and anterior gradient 2 (AGR2) in maintaining intestinal barrier function and how modifications to these systems affect mucus barrier characteristics and goblet cell dysregulation. We highlight a novel mechanism underlying the UPR-AGR2 pathway, which affects goblet cell differentiation and maturation and the synthesis and secretion of mucin by regulating epidermal growth factor receptor and mucin 2. This study provides a theoretical basis and new insights into the regulation of intestinal health in weaned piglets.

Autophagy regulation by inorganic, organic, and organic/inorganic hybrid nanoparticles: Organelle damage, regulation factors, and potential pathways

The rapid development of nanotechnology requires a more thorough understanding of the potential health effects caused by nanoparticles (NPs). As a programmed cell death, autophagy is one of the biological effects induced by NPs, which maintain intracellular homeostasis by degrading damaged organelles and removing aggregates of defective proteins through lysosomes. Currently, autophagy has been shown to be associated with the development of several diseases. A significant number of research have demonstrated that most NPs can regulate autophagy, and their regulation of autophagy is divided into induction and blockade. Studying the autophagy regulation by NPs will facilitate a more comprehensive understanding of the toxicity of NPs. In this review, we will illustrate the effects of different types of NPs on autophagy, including inorganic NPs, organic NPs, and organic/inorganic hybrid NPs. The potential mechanisms by which NPs regulate autophagy are highlighted, including organelle damage, oxidative stress, inducible factors, and multiple signaling pathways. In addition, we list the factors influencing NPs-regulated autophagy. This review may provide basic information for the safety assessment of NPs.

Effects of nano-selenium on cecum microbial community and metabolomics in chickens challenged with Ochratoxin A

Introduction

Ochratoxin A (OTA) is a widely distributed mycotoxin. Nano-selenium (Nano-Se) is an emerging form of selenium known for its superior bioavailability, remarkable catalytic efficiency, and robust adsorbing capacity. Despite these characteristics, its impact on the microbial community and metabolomics in the cecum of chickens exposed to OTA has been infrequently investigated. This research examined the microbiota and metabolomic alterations linked to OTA in chickens, with or without Nano-Se present.

Methods

A cohort of 80 healthy chickens at the age of 1 day was randomly distributed into four groups of equal numbers, namely the Se cohort (1 mg/kg Nano-Se), the OTA cohort (50 μg/kg OTA), the OTA-Se cohort (50 μg/kg OTA + 1 mg/kg Nano-Se), and the control group. Each chicken group's caecal microbiome and metabolome were characterized using 16S rRNA sequencing and Liquid chromatography coupled with mass spectrometry (LC-MS) analyses.

Results and discussion

Our results showed that the on day 21, the final body weight was significantly reduced in response to OTA treatments (p < 0.05), the average daily gain in the OTA group was found to be inferior to the other groups (p < 0.01). In addition, Nano-Se supplementation could reduce the jejunum and liver pathological injuries caused by OTA exposure. The 16S rRNA sequencing suggest that Nano-Se supplementation in OTA-exposed chickens mitigated gut microbiota imbalances by promoting beneficial microbiota and suppressing detrimental bacteria. Moreover, untargeted metabolomics revealed a significant difference in caecal metabolites by Nano-Se pretreatment. Collectively, the dataset outcomes highlighted that Nano-Se augmentation regulates intestinal microbiota and associated metabolite profiles, thus influencing critical metabolic pathways, and points to a possible food-additive product.

SeNPs alleviates BDE-209-induced intestinal damage by affecting necroptosis, inflammation, intestinal barrier and intestinal flora in layer chickens

As environmental pollutants, polybrominated diphenyl ethers (PBDEs) can have toxic effects on living organisms and has a bioaccumulative effect. Low doses of selenium nanoparticles (SeNPs) can exert antioxidant, anti-inflammatory and anti-toxin functions on the organism. This experiment evaluated SeNPs' ability to prevent chicken's intestinal damage from decabromodiphenyl ether (BDE-209) exposure. Sixty layer chickens were separated into four groups at randomly and equally: Control group, SeNPs group (1 mg/kg SeNPs), BDE-209 group (400 mg/kg BDE-209), and BDE-209 +SeNPs group (400 mg/kg BDE-209 and 1 mg/kg SeNPs), for 42 days. The results showed that BDE-209 increased MDA content, decreased the activities of T-SOD, T-AOC, GSH and iNOS, up-regulated the expression of TNF-α, RIPK1, RIPK3 and MLKL, promoted the production of inflammatory factors, reduced the levels of tight junction proteins (Claudin-1, Occludin, ZO-1). SeNPs attenuated intestinal oxidative stress, necroptosis, inflammation and intestinal barrier damage caused by BDE-209. This protective effect is associated with the MAPK/NF-κB signaling pathway. Moreover, SeNPs restores flora alpha and beta diversity, improves intestinal flora composition and its abundance. It shifts the dysbiosis of intestinal flora caused by BDE-209 to normal. Overall, SeNPs can alleviate BDE-209-induced intestinal barrier damage and intestinal flora disorders, which are associated with intestinal oxidative stress, necroptosis and inflammation.

Selenium nanoparticles alleviate deoxynivalenol-induced intestinal epithelial barrier dysfunction by regulating endoplasmic reticulum stress in IPEC-J2 cells

The intestinal epithelial barrier plays a crucial role in maintaining human and animal health. Deoxynivalenol (DON) is a mycotoxin that contaminates cereal-based foods worldwide, which is a serious threat to human and animal health. This study was aimed to investigate the protective effect of selenium nanoparticles (SeNPs) synthesized by Lactobacillus casei ATCC 393 against DON-induced intestinal epithelial barrier dysfunction and its relationship with PERK-mediated signaling pathway. IPEC-J2 cells were randomly assigned to four groups: Con (vehicle), DON (0.6 μg DON/mL, 48 h), SeNPs+DON (8 μg Se/mL, 24 h; 0.6 μg DON/mL, 48 h) and SeNPs (8 μg Se/mL, 24 h). Compared with Con group, the transepithelial electrical resistance (TEER) and the tight junction proteins expression of IPEC-J2 cells exposed to DON was increased and decreased, respectively. In addition, DON exposure led to increased ROS content, decreased antioxidant capacity, structural damage of endoplasmic reticulum (ER), and activation of endoplasmic reticulum stress (ERS)-related protein kinase R-like endoplasmic reticulum kinase (PERK) pathway in IPEC-J2. Compared with SeNPs+DON group, SeNPs alleviated oxidative stress, ER structure damage and PERK pathway activation and the increase of intestinal epithelial permeability of IPEC-J2 cells exposed to DON. PERK agonist (CCT020312) and inhibitor (GSK2656157) treatments were performed to identify the role of PERK signaling pathway in the regulatory effects of SeNPs on DON-induced intestinal epithelial barrier dysfunction. Compared with SeNPs+DON group, PERK agonist increased the expression levels of p-PERK. PERK inhibitor exerted a similar inhibitory effect to SeNPs on the p-PERK expression. In conclusion, SeNPs effectively alleviate DON-induced intestinal epithelial barrier dysfunction in IPEC-J2 cells, which are closely associated with ERS-related PERK signaling pathway. This will provide a potential solution for prevention and control of DON in the aquaculture industry.

Trends and recent progresses of selenium nanoparticles as novel autophagy regulators for therapeutic development

Autophagy, one of the major intracellular degradation systems, plays an important role in maintaining normal cellular physiological functions and protecting organisms from different diseases. Selenium (Se), an essential trace element, is involved in many metabolic regulatory signaling events and plays a key role in human health. In recent years, selenium nanoparticles (Se NPs) have attracted increasing attentions in biomedical field due to their low toxicity, high bioavailability and high bioactivity. Taking the advantage of their advanced biological activities, Se NPs can be used alone as potential therapeutic agents, or combine with other agents and served as carriers for the development of novel therapeutics. More interestingly, Se NPs have been widely reported to affect autophagy signaling, which therefor allow Se NPs to be used as potential therapeutic agents against different diseases. Here, this review suggested the relationships between Se and autophagy, followed by the trends and recent progresses of Se NPs for autophagy regulation in different diseased conditions. More importantly, this work discussed the roles and potential mechanisms of Se NPs in autophagy regulating, which might enhance our understanding about how Se NPs regulate autophagy for potential disease treatment. This work is expected to promote the potential application of Se NPs as novel autophagy regulators, which might benefit the development of novel autophagy associated therapeutics.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.