Protective effect of Ganoderma atrum polysaccharide on acrolein-induced macrophage injury via autophagy-dependent apoptosis pathway

Structural characteristics and anti-tumor activity of alkali-extracted acidic polysaccharide extracted from Panax ginseng

In this paper, Panax ginseng residue after boiling water extraction was reused to obtain the acidic polysaccharide PGP-1, and its structural characterization and anti-tumor activity were investigated. Structural experiments showed that PGP-1 consisted of Rha, Ara, Glc, Gal, and GalA in a molar ratio of 0.04:0.31:1.00:0.28:0.54. The backbone of PGP-1 was formed by the 1 → 4 glycosidic linkage of HG and RG-I, with Araf, Glcp, and Galp sidechains attached at position O-3. In vitro experiments showed that PGP-1 induced apoptosis in MGC803 cells through the mitochondrial pathway, with apoptotic features such as nuclear consolidation and generation of apoptotic vesicles. Animal experiments showed that PGP-1 could inhibit the proliferation of tumor cells in H22 tumor-bearing mice by improving the status of immune organs, enhancing the activity of immune cells, and increasing the levels of serum cytokines and apoptosis-related proteins, with the tumor inhibition rate reaching 45.70 % (200 mg/kg). The above experimental results indicated that Panax ginseng polysaccharides had the potential to be functional anti-tumor agents.

Structure-function insights of natural Ganoderma polysaccharides: advances in biosynthesis and functional food applications

Ganoderma polysaccharides (GPs), derived from various species of the Ganoderma genus, exhibit diverse bioactivities, including immune modulation, anti-tumor effects, and gut microbiota regulation. These properties position GPs as dual-purpose agents for medicinal and functional food development. This review comprehensively explores the structural complexity of six key GPs and their specific mechanisms of action, such as TLR signaling in immune modulation, apoptosis pathways in anti-tumor activity, and their prebiotic effects on gut microbiota. Additionally, the structure-activity relationships (SARs) of GPs are highlighted to elucidate their biological efficacy. Advances in green extraction techniques, including ultrasonic-assisted and enzymatic methods, are discussed for their roles in enhancing yield and aligning with sustainable production principles. Furthermore, the review addresses biotechnological innovations in polysaccharide biosynthesis, improving production efficiency and making large-scale production feasible. These insights, combined with ongoing research into their bioactivity, provide a solid foundation for developing health-promoting functional food products that incorporate GPs. Furthermore, future research directions are suggested to optimize biosynthesis pathways and fully harness the health benefits of these polysaccharides.

The roles and regulatory mechanisms of cigarette smoke constituents in vascular remodeling

Vascular remodeling is a dynamic process involving cellular and molecular changes, including cell proliferation, migration, apoptosis and extracellular matrix (ECM) synthesis or degradation, which disrupt the homeostasis of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). Cigarette smoke exposure (CSE) is thought to promote vascular remodeling, but the components are complex and the mechanisms are unclear. In this review, we overview the progression of major components of cigarette smoke (CS), such as nicotine and acrolein, involved in vascular remodeling in terms of ECs injury, VSMCs proliferation, migration, apoptosis, and ECM disruption. The aim was to elucidate the effects of different components of CS on different cells of the vascular system, to discover the relevance of their actions, and to provide new references for future studies.

The mechanism of acrolein exposure inhibited the release of neutrophil extracellular traps: By reducing respiratory burst and Raf/MEK/ERK pathway and promote cell apoptosis

Acrolein (AC) is a highly toxic volatile substance in the environment, and studies have found that excessive AC had a toxic effect on the immune system. Neutrophils are the first line of defense against pathogen invasion. The release of neutrophil extracellular traps (NETs) is a protective mechanism for neutrophils, and its release is affected by environmental pollutants. However, the effect of AC on NETs release and its mechanism remains unclear. In this study, chicken peripheral blood neutrophils were pretreated with 20 μM AC and treated with 5 μM Phorbol 12-myristate 13-acetate (PMA) to stimulate the release of NETs. The results showed that AC exposure significantly inhibited the release of NETs induced by PMA, respiratory burst, and the expression levels of phospho-rapidly accelerated fibrosarcoma (p-Raf), phospho-mitogen-activated extracellular signal-regulated kinase (p-MEK) and phospho-extracellular regulated protein kinases (p-ERK). In addition, AC exposure significantly inhibited the expression of B-cell lymphoma-2 (Bcl-2) and promoted the expression of apoptotic factors Bcl2-Associated X (Bax), cytochrome c (Cyt C), cysteinyl aspartate specific proteinase 9 (Casp 9) and cysteinyl aspartate specific proteinase 3 (Casp 3). Further inhibition of neutrophil apoptosis significantly improved the release of NETs. The above results indicated that AC exposure led to a decrease in the formation of NETs, which is caused by excessive AC-induced neutrophil apoptosis. Our study clarified the immune toxicity mechanism of AC on chickens, which is of great significance and reference value for protecting the ecological environment and poultry health.

Protective effects and mechanism of Paecilomyces cicadae TJJ1213 intracellular polysaccharide against H2 O2 -induced PC12 cells damage

Oxidative stress is a key process in the development of neurodegenerative diseases. More attention is needed to screen natural antioxidants and explore pharmacological mechanisms. Natural product polysaccharides with no toxic side effects have powerful antioxidant activity. Two purified intracellular polysaccharide fractions (IPS1 and IPS2) from Paecilomyces cicadae TJJ1213 was isolated. Then, a model of H2 O2 -induced oxidative stress in PC12 cells was established to investigate the neuroprotective role of IPS and elucidate the potential protection mechanism. Results showed that IPS1 and IPS2 reduced reactive oxygen species (ROS) production, inhibited the leakage of lactate dehydrogenase (LDH) and Ca2+ and attenuated the expression of apoptotic proteins. In addition, western blots displayed that IPS1 and IPS2 significantly inhibited mitophagy induced by H2 O2 in PC12 cells via PINK/Parkin pathway. Therefore, IPS1 and IPS2 deserved further investigation as protective agents against neurodegenerative diseases.

Cell Protection and Crystal Endocytosis Inhibition by Sulfated Laminaria Polysaccharides Against Nano-COM-Induced Oxidative Damage in Renal Epithelial Cells

Background: The damage to renal tubular epithelial cells is closely related to the formation of kidney stones. At present, research on drugs that can protect cells from damage remains limited. Methods: This study aims to explore the protective effects of four different sulfate groups (-OSO₃ ^-) of Laminaria polysaccharides (SLPs) on human kidney proximal tubular epithelial (HK-2) cells and determine the difference in the endocytosis of nano-sized calcium oxalate monohydrate (COM) crystals before and after protection. COM with a size of 230 ± 80 nm was used to damage HK-2 cells to establish a damage model. The protection capability of SLPs (LP0, SLP1, SLP2, and SLP3) with -OSO₃ ^- contents of 0.73, 15, 23, and 31%, respectively, against COM crystal damage and the effect of SLPs on the endocytosis of COM crystals were studied. Results: Compared with that of the SLP-unprotected COM-injured group, the cell viability of the SLP-protected group was improved, healing capability was enhanced, cell morphology was restored, production of reactive oxygen species was reduced, mitochondrial membrane potential and lysosome integrity were increased, intracellular Ca²⁺ level and autophagy were decreased, cell mortality was reduced, and internalized COM crystals were lessened. The capability of SLPs to protect cells from damage and inhibit the endocytosis of crystals in cells enhanced with an increase in the -OSO₃ ^- content of SLPs. Conclusions: SLPs with a high -OSO₃ ^- content may become a potential green drug for preventing the formation of kidney stones.

Apigenin and its octoic acid diester attenuated glycidol-induced autophagic-dependent apoptosis via inhibiting the ERK/JNK/p38 signaling pathways in human umbilical vein endothelial cells (HUVECs)

Glycidol is a well-known food contaminant mainly formed in refined edible oils and various thermally processed foods. Here, we studied the toxicity effects and related mechanism of glycidol on Human umbilical vein endothelial cells (HUVECs). Glycidol was found to induce Gap period 2 (G2)/Mitosis (M) phase cell cycle arrest, apoptosis, and autophagy in HUVECs. Inhibition of autophagy by 3-methyladenine (3-MA) attenuated glycidol-induced cell death, suggesting that glycidol-induced apoptosis was autophagy-dependent. Moreover, glycidol treatment induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38. Inhibition of ERK, JNK, and p38 phosphorylation by the inhibitors U0126, SP600125, and SB203580 attenuated glycidol-induced autophagy and prevented glycidol-mediated reduction in cell viability, demonstrating that glycidol inhibited HUVECs growth by inducing autophagic-dependent apoptosis through activation of the ERK, JNK and p38 signaling pathways. In addition, apigenin (API) and its octoic acid diester apigenin-7 (API-C8), 4'-O-dioctanoate were found to significantly attenuate glycidol-induced cell growth inhibition by inhibiting the above signaling pathways. Collectively, glycidol induces autophagic-dependent apoptosis via activating the ERK/JNK/p38 signaling pathways in HUVECs and API-C8 could attenuate the toxicity effects.

Apigenin and apigenin-7, 4'-O-dioctanoate protect against acrolein-aggravated inflammation via inhibiting the activation of NLRP3 inflammasome and HMGB1/MYD88/NF-κB signaling pathway in Human umbilical vein endothelial cells (HUVEC)

Exposure to acrolein, one environmental and dietary pollutant, has been shown to cause inflammation. Here, we reported for the first time that acrolein aggravated lipopolysaccharide (LPS)-induced inflammation in Human umbilical vein endothelial cells (HUVEC) as evidenced by the further increased mRNA expression of three pro-inflammatory cytokines, including interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Acrolein also further increased the generation of reactive oxygen species (ROS) and decreased the activity of glutathione peroxidase (GSH-Px) in LPS-pretreated HUVEC. Moreover, acrolein treatment further increased the nucleotide oligomerization domain-like receptor protein 3 (NLRP3) and apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) expression, caspase-1 cleavage, and downstream matures interleukin 18 (IL-18) and IL-1β level in LPS-pretreated HUVEC. Acrolein treatment also further increased the expressions of high-mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and phospho-NF-κB P65 (P-P65) in the LPS pre-treated HUVEC. Thus, acrolein aggravated LPS-induced HUVEC inflammation through induction of oxidative stress, and activation of NLRP3 inflammasome and HMGB1/MYD88/NF-κB signaling pathway. In addition, apigenin and apigenin-7, 4'-O-dioctanoate attenuated acrolein-aggravated inflammation by targeting the above signaling pathways. Our findings could help to develop potential therapeutic strategies against acrolein-enhanced inflammation.

Interaction between nanometer calcium oxalate and renal epithelial cells repaired with carboxymethylated polysaccharides

OBJECTIVE

Injury of renal tubular epithelial cells (HK-2) is an important cause of kidney stone formation. In this article, the repairing effect of polysaccharide (PCP0) extracted from the traditional Chinese medicine Poria cocos and its carboxymethylated derivatives on damaged HK-2 cells was studied, and the differences in adhesion and endocytosis of the cells to nanometer calcium oxalate monohydrate (COM) before and after repair were explored.

METHODS

Sodium oxalate (2.8 mmol/L) was used to damage HK-2 cells to establish a damage model, and then Poria cocos polysaccharides (PCPs) with different carboxyl (COOH) contents were used to repair the damaged cells. The changes in the biochemical indicators of the cells before and after the repair and the changes in the ability to adhere to and internalize nano-COM were detected.

RESULTS

The natural PCPs (PCP0, COOH content = 2.56%) were carboxymethylated, and three carboxylated modified Poria cocos with 7.48% (PCP1), 12.07% (PCP2), and 17.18% (PCP3) COOH contents were obtained. PCPs could repair the damaged HK-2 cells, and the cell viability was enhanced after repair. The cell morphology was gradually repaired, the proliferation and healing rate were increased. The ROS production was reduced, and the polarity of the mitochondrial membrane potential was restored. The level of intracellular Ca²⁺ ions decreased, and the autophagy response was weakened.

CONCLUSION

The cells repaired by PCPs inhibited the adhesion to nano-COM and simultaneously promoted the endocytosis of nano-COM. The endocytic crystals mainly accumulated in the lysosome. Inhibiting adhesion and increasing endocytosis could reduce the nucleation, growth, and aggregation of cell surface crystals, thereby inhibiting the formation of kidney stones. With the increase of COOH content in PCPs, its ability to repair damaged cells, inhibit crystal adhesion, and promote crystal endocytosis all increased, that is, PCP3 with the highest COOH content showed the best ability to inhibit stone formation.

Acrolein Promotes Aging and Oxidative Stress via the Stress Response Factor DAF-16/FOXO in Caenorhabditis elegans

For this investigation, Caenorhabditis elegans (C. elegans) served, for the first time, as a model organism to evaluate the toxic effect and possible underlying mechanisms under acrolein (ACR) exposure. The results showed that ACR exposure (12.5–100 μM) shortened the lifespan of C. elegans. The reproductive capacity, body length, body width, and locomotive behavior (head thrash) of C. elegans were diminished by ACR, especially the doses of 50 and 100 μM. Furthermore, ACR significantly enhanced the endogenous ROS levels of C. elegans, inhibited the antioxidant-related enzyme activities, and affected the expression of antioxidant related genes. The increasing oxidative stress level promoted the migration of DAF-16 into the nucleus that was related to the DAF-16/FOXO pathway. It was also confirmed by the significant decrease of the lifespan-shortening trend in the daf-16 knockout mutant. In conclusion, ACR exposure induced aging and oxidative stress in C.elegans, resulting in aging-related decline and defense-related DAF-16/FOXO pathways’ activation.

Protective Effect of Ganoderma atrum Polysaccharide on Acrolein-Induced Apoptosis and Autophagic Flux in IEC-6 Cells

This study was designed to explore the beneficial effect and mechanism of Ganoderma atrum (G. atrum) polysaccharide (PSG-1) on acrolein-induced IEC-6 cells. Our results indicated that PSG-1 significantly reduced the impairment of acrolein on cell viability, decreased oxidative stress, and enabled normal expression of tight junction (TJ) proteins that were inhibited by acrolein in IEC-6 cells. Furthermore, PSG-1 attenuated the elevation of microtubule-associated proteins light chain 3 (LC3) and Beclin 1-like protein 1 (Beclin 1) and increased the protein levels of phospho-mTOR (p-mTOR) and phospho-akt (p-akt), indicating that PSG-1 activated the mammalian target of rapamycin (mTOR) signaling pathway and alleviated acrolein-induced autophagy in IEC-6 cells. Moreover, PSG-1 markedly attenuated the acrolein-induced apoptosis, as evidenced by the increase in mitochondrial membrane potential (MMP) and B-cell lymphoma 2 (Bcl-2) expression, and the decrease in cysteine aspartate lyase (caspase)-3 and caspase-9. In addition, autophagy the inhibitor inhibited acrolein-induced TJ and apoptosis of IEC-6 cells, while the apoptosis inhibitor also inhibited acrolein-induced TJ and autophagy, suggesting that autophagy and apoptosis were mutually regulated. Taken together, the present study proved that PSG-1 could protect IEC-6 cells from acrolein-induced oxidative stress and could repair TJ by inhibiting apoptosis and autophagic flux, where autophagy and apoptosis were mutually regulated.

Exploring the molecular mechanisms of the inhibition of acrolein-induced BEAS-2B cytotoxicity by luteolin using network pharmacology and cell biology technology

Acrolein is a highly reactive unsaturated hazardous air pollutant, which is extremely irritating to the respiratory tract. Luteolin, an active flavonoid compound, possesses multiple biological activities. The purpose of this study was to evaluate the mechanism of the inhibition of acrolein-induced human bronchial epithelial (BEAS-2B) cells cytotoxicity by luteolin using network pharmacology and cell biology technology. Firstly, network pharmacology results indicated that oxidative stress processes might play an important role in luteolin inhibiting lung injury. Next, it was verified at the cellular level. Reactive oxygen species (ROS) generation increased, glutathione (GSH) level decreased after exposure to acrolein. MAPK signaling pathways were activated, which activated downstream IκBα/NF-κB signaling pathways. Meanwhile, acrolein caused oxidative DNA damage and double-strand breaks, induced DNA damage response (DDR) and apoptosis. These adverse effects were significantly reversed by luteolin, which inhibited the activation of MAPK/IκBα/NF-κB and DDR pathways, and reduced the ratio of Bax/Bcl-2. Moreover, luteolin also had a similar effect to antioxidant N-acetyl cysteine (NAC) in the regulation of signaling transduction mechanisms, which indicated that the regulation of oxidative stress played an important role in the process. These results provide an experimental basis for elucidating the molecular mechanisms of the inhibition of acrolein-induced BEAS-2B cytotoxicity with luteolin.

Advances in the regulation of natural polysaccharides on human health: The role of apoptosis/autophagy pathway

Due to the multiple biological activities of polysaccharides, their great potential as "natural drugs" for many diseases has been the subject of continuous exploration in the field of food and nutrition. Apoptosis and autophagy play a key role in mammalian growth, development and maintenance of cellular homeostasis. Recent studies suggest that apoptosis/autophagy may be the key regulatory target for the beneficial effects of polysaccharides. However, the regulation of apoptosis and autophagy by polysaccharides is not consistent in different disease models. Therefore, this review outlined the relationship between apoptosis/autophagy and some common human diseases, then discussed the role of apoptosis/autophagy pathway in the regulation of human health by polysaccharides, Furthermore, the application of visualization, imaging and multi-omics techniques was proposed in the future trend. The present review may be beneficial to accelerate our understanding of the anti-disease mechanisms of polysaccharides, and promote the development and utilization of polysaccharides.

"Dialogue" between Caco-2 and DCs regulated by Ganoderma atrum polysaccharide in intestinal-like Caco-2/DCs co-culture model

The previous research has indicated that Ganoderma atrum polysaccharide (PSG-1) indirectly affects the immune function of dendritic cells (DCs) in intestinal-like Caco-2/DCs co-culture model, in which NF-κB and MAPK pathway play an essential role. To explore the interaction of Caco-2 in the interaction between the intestinal epithelium and its internal immune cells, the intestinal-like Caco-2/DCs co-culture model was developed. All transcripts of Caco-2 treated with or without PSG-1 were globally screened by RNA-seq. The expression of 452 genes regulated by PSG-1 was statistically significant, the counts of up-regulated and down-regulated genes were 198 and 256, respectively. According to KEGG analysis, tumor necrosis factor (TNF)-α and NF-κB signaling pathways of Caco-2 were selected to elucidate the mechanism of interaction between Caco-2/DCs induced by PSG-1. After the addition of TNF-α inhibitor Apremilast and NF-κB inhibitor BAY11-70821 in Caco-2, expression of cytokines (TNF-α, IL-6, IL-1β, IL-10), chemokines (RANTES, MIP-1α, MCP-1), and the key proteins of MAPK and NF-κB pathways of DCs were all reduced. In summary, "dialogue" between Caco-2 and DCs was regulated by PSG-1 through TNF-α and NF-κB signaling pathways of Caco-2 in the model.

A Ganoderma atrum polysaccharide alleviated DSS-induced ulcerative colitis by protecting the apoptosis/autophagy-regulated physical barrier and the DC-related immune barrier

Polysaccharides are one of the main active substances in Ganoderma atrum (G. atrum). The purpose of this study was to explore the protective effect of a G. atrum polysaccharide (PSG-1) on DSS-induced colitis and the underlying mechanism. The results showed that PSG-1 could maintain the integrity of the intestinal structure by promoting the expression of goblet cells and levels of tight junction proteins in the colon of DSS-induced colitis mice. Furthermore, PSG-1 relieved the inhibition of Bcl-2 and the overexpression of caspase-3 and caspase-9 caused by DSS. Simultaneously, PSG-1 restored the expression of Atg5, Atg7 and beclin-1 and inhibited the p-akt and p-mTOR levels, suggesting that PSG-1 promoted autophagy via the Akt/mTOR pathway. Moreover, PSG-1 inhibited the content of DCs in the colon and modulated the expression of IL-10 in DCs. In conclusion, PSG-1 alleviated DSS-induced ulcerative colitis by protecting the apoptosis/autophagy-regulated physical barrier and the DC-related immune barrier.

Polysaccharides of Dendrobium officinale Kimura & Migo Leaves Protect Against Ethanol-Induced Gastric Mucosal Injury via the AMPK/mTOR Signaling Pathway in Vitro and vivo

Ethanol-induced gastric mucosal injury is a common gastrointestinal disorder. Polysaccharides separated from herbs have been shown to be effective for ethanol-induced gastric mucosal injury, but whether the polysaccharides from Dendrobium officinale Kimura & Migo leaves (LDOP-1) protected mucosa from ethanol-induced injury remains unknown. Thus, the present study carried out gastric mucosal protection and the mechanism of LDOP-1 in vivo and vitro. The chemical composition of LDOP-1 was a heteropolysaccharide comprising mannose, galacturonic acid, glucose, galactose, and arabinose at a molar ratio of 2.0:1.1:0.7:0.5:0.4. Pharmacological results showed that LDOP-1 significantly reduced gastric mucosal injury score and pathological injury, improved antioxidant capacity, reduced the level of reactive oxygen species, and reversed the apoptosis of GES-1 in vivo and vitro. Research showed that LDOP-1 pretreatment upregulated the expression level of p-AMPK, LC3β, HO-1, and Beclin-1; downregulated the expression level of p-mTOR and p62; and reversed the expression level of caspase3, Bax, and Bcl-2. This study was the first to demonstrate that LDOP-1 could protect against ethanol-induced gastric mucosal injury via the AMPK/mTOR signaling pathway in vitro and vivo.

Acrolein exerts a genotoxic effect in the Leydig cells by stimulating DNA damage-induced apoptosis

Acrolein is a highly reactive unsaturated organic molecule and has harmful effects on human health. Acrolein is generally formed in heat-treated foods above 150 °C, as well as in the combustion of gasoline, wood industry, plastic waste, and tobacco smoke. In this study, the effects of acrolein on genotoxicity in Leydig cells and the underlying mechanisms are aimed to be clarified. In addition, the toxicogenomic profile of acrolein was studied in terms of both apoptosis and steroidogenesis. Real-time PCR and ELISA tests were used to analyses of steroidogenic endpoints. Apoptosis was evaluated with double fluorescence staining and gene expression analyses of related genes. Comet assay was used to determine the genotoxicity. The results showed that acrolein caused concentration-dependent inhibition on cell viability at 8 μM and above concentrations, decreased testosterone production at 13.6 and 19.7 μM concentrations, and suppressed expression levels of genes that play an important role in steroidogenic pathway. Furthermore, acrolein downregulated expression of anti-apoptotic Bcl2 gene and upregulated expression of pro-apoptotic Bax, Casp3, and Trp53 gene after 24-h treatment in 7.4, 13.6, and 19.7 μM acrolein-exposed Leydig cells. The results of comet assay showed that acrolein significantly induced tail length, tail % DNA, and Olive tail moment. Overall, it was concluded that acrolein-induced cell damage in Leydig cells may be due to formation of genetic damage in steroidogenesis and apoptosis.

Ganoderma atrum polysaccharide ameliorates intestinal mucosal dysfunction associated with autophagy in immunosuppressed mice

The aim of this study was to investigate the protective effect and underlying mechanisms of Ganoderma atrum polysaccharide (PSG-1) on cyclophosphamide (Cy)-induced intestinal mucosal dysfunction in mice. Results showed that PSG-1 promoted the formation of IgA-secreting cells, modulated sIgA, IgE, IgG, IgM secretion, and improved TLR-2, TLR-4, TLR-6 mRNA levels while these factors were suppressed after Cy treatment. CD4⁺ and CD8⁺ T cell numbers were also elevated by PSG-1. Cytokines including IFN-γ, TNF-α, IL-2, IL-12p70, IL-4, IL-1β, IL-17, IL-21, IL-23, TGF-β3 and transcription factors including T-bet, GATA-3, RORγt, Foxp3 increased after PSG-1 administration. Besides, PSG-1 reversed goblet cell numbers, and upregulated tight junction proteins like ZO-1, occludin and claudin-1 in immunosuppressed mice. Apart from these, the autophagy-related proteins LC3, Beclin-1, Atg5 and Atg7 were enhanced by PSG-1. These findings demonstrated that PSG-1 could ameliorate Cy-induced impairment of intestinal immunity and mucosal integrity, which maybe associated with autophagy in mice.