Effects of Lipid Peroxidation-Mediated Ferroptosis on Severe Acute Pancreatitis-Induced Intestinal Barrier Injury and Bacterial Translocation

Inflammatory immunity and bacteriological perspectives: A new direction for copper treatment of sepsis

Copper is an essential trace element for all aerobic organisms because of its unique biological functions. In recent years, researchers have discovered that copper can induce cell death through various regulatory mechanisms, thereby inducing inflammation. Efforts have also been made to alter the chemical structure of copper to achieve either anticancer or anti-inflammatory effects. The copper ion can exhibit bactericidal effects by interfering with the integrity of the cell membrane and promoting oxidative stress. Sepsis is a systemic inflammatory response caused by infection. Some studies have revealed that copper is involved in the pathophysiological process of sepsis and is closely related to its prognosis. During the infection of sepsis, the body may enhance the antimicrobial effect by increasing the release of copper. However, to avoid copper poisoning, all organisms have evolved copper resistance genes. Therefore, further analysis of the complex relationship between copper and bacteria may provide new ideas and research directions for the treatment of sepsis.

Ferroptosis exacerbates hyperlipidemic acute pancreatitis by enhancing lipid peroxidation and modulating the immune microenvironment

Abnormal activation of ferroptosis worsens the severity of acute pancreatitis and intensifies the inflammatory response and organ damage, but the detailed underlying mechanisms are unknown. Compared with other types of pancreatitis, hyperlipidemic acute pancreatitis (HLAP) is more likely to progress to necrotizing pancreatitis, possibly due to peripancreatic lipolysis and the production of unsaturated fatty acids. Moreover, high levels of unsaturated fatty acids undergo lipid peroxidation and trigger ferroptosis to further exacerbate inflammation and worsen HLAP. This paper focuses on the malignant development of hyperlipidemic pancreatitis with severe disease combined with the core features of ferroptosis to explore and describe the mechanism of this phenomenon and shows that the activation of lipid peroxidation and the aberrant intracellular release of many inflammatory mediators during ferroptosis are the key processes that regulate the degree of disease development in patients with HLAP. Inhibiting the activation of ferroptosis effectively reduces the intensity of the inflammatory response, thus reducing organ damage in patients and preventing the risk of HLAP exacerbation. Additionally, this paper summarizes the key targets and potential therapeutic agents of ferroptosis associated with HLAP deterioration to provide new ideas for future clinical applications.

Ferroptosis contributes to airway epithelial E-cadherin disruption in a mixed granulocytic asthma mouse model

Aberrant expression of airway epithelial E-cadherin is a key feature of asthma, yet the underlying mechanisms are largely unknown. Ferroptosis is a novel form of regulated cell death involved in asthma pathogenesis. This study was aimed to evaluate the role of ferroptosis and to investigate whether ferroptosis mediates E-cadherin disruption in mixed granulocyte asthma (MGA). Two murine models of MGA were established using toluene diisocyanate (TDI) or ovalbumin with Complete Freund's Adjuvant (OVA/CFA). Specific antagonists of ferroptosis, including Liproxstatin-1 (Lip-1) and Ferrostatin-1 (Fer-1) were given to the mice. The allergen-exposed mice displayed markedly shrunk mitochondria in the airway epithelia, with decreased volume and denser staining accompanied by down-regulated GPX4 as well as up-regulated FTH1 and malondialdehyde, which are markers of ferroptosis. Decreased pulmonary expression of E-cadherin was also observed, with profound loss of membrane E-cadherin in the airway epithelia, as well as increased secretion of sE-cadherin. Treatment with Lip-1 not only showed potent protective effects against the allergen-induced airway hyperresponsiveness and inflammatory responses, but also rescued airway epithelial E-cadherin expression and inhibited the release of sE-cadherin. Taken together, our data demonstrated that ferroptosis mediates airway epithelial E-cadherin dysfunction in MGA.

circ_UTRN inhibits ferroptosis of ARJ21 cells to attenuate acute pancreatitis progression by regulating the miR-760-3p/FOXO1/GPX4 axis

Aim

To explore the function of circ_UTRN in acute pancreatitis (AP).

Methods

After exposing AR42J cells to caerulein, the levels of circ_UTRN, miR-760-3p, and glutathione peroxidase 4 (GPX4) were determined by quantitative polymerase chain reaction. Additionally, GPX4 and forkhead box O1 (FOXO1) protein levels were assessed by western blot. The levels of oxidative stress and ferroptosis in the supernatant of the treated AR42J cells were also assessed using commercial kits.

Results

circ_UTRN inhibited caerulein-induced oxidative stress and ferroptosis by binding with miR-760-3p. Additionally, miR-760-3p directly targeted FOXO1, thereby regulating GPX4 levels. Furthermore, GPX4 knockdown abolished the effect of miR-760-3p downregulation in AP.

Conclusion

circ_UTRN inhibited oxidative stress and ferroptosis by regulating the miR-760-3p/FOXO1/GPX4 axis. This is a potential new treatment strategy for AP.

Ageratina adenophora causes intestinal integrity damage in goats via the activation of the MLCK/ROCK signaling pathway

As a global toxin invasive species, the whole herb of Ageratina adenophora (A. adenophora) contains various sesquiterpenes, which can cause various degrees of toxic reactions characterized by inflammatory damage when ingested by animals. Current studies on the toxicity of A. adenophora have focused on parenchymatous organs such as the liver and spleen, but few studies have been conducted on the intestine as the organ that is first exposed to A. adenophora and digests and absorbs its toxic components. In this study, after feeding goats with 40 % A. adenophora herb powder for 90 d, we found that the intestinal structure of goats showed pathological changes characterized, and the damage to the small intestinal segments was more severe than that of the large intestine. The MLCK/ROCK signaling pathway was activated, the cytoskeleton underwent centripetal contraction, the composition of tight junctions between intestinal epithelial cells was altered table, Occludin, Claudin-1 and Zonula occluden (ZO-1) amount was decreased, and the intestinal mechanical barrier was disrupted. The intestinal damage markers diamine oxidase (DAO) and D-lactate (D-LA) levels were elevated. In addition, we also found that intestinal bacteria translocate and enter the portal vein to colonize the liver and mesenteric lymph nodes. The expression of intestinal pro-inflammatory factors and anti-inflammatory factors was changed, the intestinal immune function was disrupted. The present study is the first to analyze the mechanism of poisoning of A. adenophora from the intestinal tract in compound-gastric animals.

METTL14 depletion ameliorates ferroptosis in severe acute pancreatitis by increasing the N6-methyladenosine modification of ACSL4 and STA1

Methyltransferase-like 14 (METTL14) is implicated in the regulation of various inflammatory disorders. However, its function and molecular mechanism in severe acute pancreatitis (SAP) remains unrevealed. Here we reported an increase in METTL14 in the pancreas of SAP mice and cerulein-LPS-treated AR42J cells. METTL14 depletion reversed inflammatory response and ferroptosis by reducing the expression of SAT1 (spermidine/spermine N1-acetyltransferase 1) and ACSL4 (acyl-CoA synthetase long chain family member 4) in an m6A-dependent manner. IGF2BP2 (insulin like growth factor 2 mRNA binding protein 2) could recognize m6A-modified SAT1 and ACSL4 mRNA and enhance their stability. Moreover, METTL14 depletion ameliorated pancreatic injury, inflammation, and ferroptosis induced by SAP. METTL14 overexpression aggravated SAP by promoting ferroptosis in vivo. Therefore, these results demonstrated that METTL14-induced ferroptosis promoted the progression of SAP, and targeting METTL14 or ferroptosis could be a potential strategy for the prevention and treatment of SAP.

FGF10 protects against LPS-induced epithelial barrier injury and inflammation by inhibiting SIRT1-ferroptosis pathway in acute lung injury in mice

Pulmonary alveolar epithelial cell injury is considered the main pathological and physiological change in acute lung injury. Ferroptosis in alveolar epithelial cells is one of crucial factors contributing to acute lung injury (ALI). Therefore, reducing ferroptosis and repair epithelial barrier is very necessary. More and more evidence suggested that FGF10 plays an important role in lung development and repair after injury. However, the relationship between FGF10 and ferroptosis remains unclear. This study aims to explore the regulatory role of FGF10 on ferroptosis in ALI. Differential gene expression analysis indicated that genes associated with ferroptosis showed that FGF10 can significantly alleviate LPS induced lung injury and epithelial barrier damage by decreasing levels of malonaldehyde(MDA), and lipid ROS. SIRT1 activator (Resveratrol) and inhibitor (EX527) are used in vivo showed that FGF10 protects ferroptosis of pulmonary epithelial cells through SIRT1 signal. Furthermore, knockdown of FGFR2 gene reduced the protective effect of FGF10 on acute lung injury in mice and SIRT1 activation. After the application of NRF2 inhibitor ML385 in vitro, the results showed that SIRT1 regulated the expression of ferroptosis related proteins NRF2, GPX4 and FTH1 are related to activation of NRF2. These data indicate that SIRT-ferroptosis was one of the critical mechanisms contributing to LPS-induced ALI. FGF10 is promising as a therapeutic candidate against ALI through inhibiting ferroptosis.

NCOA4-mediated ferritinophagy aggravate intestinal oxidative stress and ferroptosis after traumatic brain injury

Intestinal injury caused by traumatic brain injury (TBI) seriously affects patient prognosis; however, the underlying mechanisms are unknown. Recent studies have demonstrated that ferritinophagy-mediated ferroptosis is involved in several intestinal disorders. However, uncertainty persists regarding the role of ferritinophagy-mediated ferroptosis in the intestinal damage caused by TBI. High-throughput transcriptional sequencing was used to identify the genes that were differentially expressed in the intestine after TBI. The intestinal tissues were harvested for hematoxylin and eosin staining (HE), immunofluorescence, and western blot (WB). Lipid peroxide markers and iron content in the intestines were determined using the corresponding kits. High throughput sequencing revealed that the ferroptosis signaling pathway was enriched, demonstrating that intestinal damage caused by TBI may include ferroptosis. Chiu's score, tight junction proteins, and lipid peroxide indicators demonstrated that TBI caused an intestinal mucosal injury that persisted for several days. The ferroptosis pathway-related proteins, ferritin heavy polypeptide 1 (Fth1) and glutathione peroxidase 4 (GPX4), exhibited dynamic changes. The results indicated that lipid peroxide products were markedly increased, whereas antioxidant enzymes were markedly decreased. WB analysis demonstrated that the expression levels of nuclear receptor coactivator 4 (NCOA4), LC3II/LC3I, and p62 were markedly upregulated, whereas those of GPX4 and Fth1 were markedly downregulated. In addition, ferrostatin-1 attenuates intestinal ferroptosis and injury post-TBI in vivo. Intriguingly, 3-methyladenine (3-MA) reduces intestinal ferritin decomposition, iron accumulation, and ferroptosis after TBI. Moreover, 3-MA markedly reduced intestinal apoptosis. In conclusion, NCOA4 mediated ferritinophagy and ferroptosis play roles in intestinal oxidative stress injury post-TBI. This study provides a deeper understanding of the mechanisms underlying intestinal damage following TBI.

Fabp5 is a common gene between a high-cholesterol diet and acute pancreatitis

Background and aims

Hypercholesterolemia has been identified as risk factor for severe acute pancreatitis (AP). We aimed to identify the common differentially expressed genes (DEGs) between a high-cholesterol diet and AP.

Methods

We retrived gene expression profiles from the GEO database. DEGs were assessed using GEO2R. For AP hub genes, we conducted functional enrichment analysis and protein-protein interaction (PPI) analysis. GeneMANIA and correlation analysis were employed to predict potential DEG mechanisms. Validation was done across various healthy human tissues, pancreatic adenocarcinoma, peripheral blood in AP patients, and Sprague-Dawley rats with AP.

Results

The gene "Fabp5" emerged as the sole common DEG shared by a high-cholesterol diet and AP. Using the 12 topological analysis methods in PPI network analysis, Rela, Actb, Cdh1, and Vcl were identified as hub DEGs. GeneMANIA revealed 77.6% physical interactions among Fabp5, TLR4, and Rela, while genetic correlation analysis indicated moderate associations among them. Peripheral blood analysis yielded area under the ROC curve (AUC) values of 0.71, 0.63, 0.74, 0.64, and 0.91 for Fabp5, TLR4, Actb, Cdh1 genes, and artificial neural network (ANN) model respectively, in predicting severe AP. In vivo immunohistochemical analysis demonstrated higher Fabp5 expression in the hyperlipidemia-associated AP group compared to the AP and control groups.

Conclusion

Fabp5 emerged as the common DEG connecting a high-cholesterol diet and AP. Rela was highlighted as a crucial hub gene in AP. Genetic interactions were observed among Fabp5, TLR4, and Rela. An ANN model consisting of Fabp5, TLR4, Actb, and Cdh1 was helpful in predicting severe AP.

The role of iron and ferroptosis in the pathogenesis of acute pancreatitis

Acute pancreatitis (AP) is an inflammatory disease of the pancreas. Iron is an essential element for life and is involved in many metabolic processes. Ferroptosis is a type of regulated cell death that is triggered by iron and oxidative stress. A well-established mouse AP model was adopted to study the role of iron and ferroptosis in the pathogenesis of pancreatitis. Mice were injected with cerulein to induce AP, and pancreatic tissue samples were analyzed to determine the pathology, cell death, iron deposition, expression of iron transporters, and lipid peroxidation. The role of iron was studied by giving mice extra iron or iron chelator. In vitro studies with acinar cells with ferroptosis activator and inhibitor were also performed to assess the inflammatory response. Iron was found accumulated in the pancreatic tissue of mice who suffered cerulein-induced pancreatitis. Cell death and lipid peroxidation increased in these tissues and could be further modulated by iron dextran or iron chelator. Mice given Hemin through gavage had reduced levels of GSH in pancreatic tissue and increased inflammatory response. Studies with acinar cells showed increased levels of lipid peroxidation and ferroptosis-specific mitochondrial damage when treated with ferroptosis inducer and inflammatory cytokines.

An in-Depth Exploration of the Genetic Interaction Network Between Ferroptosis and Acute Pancreatitis

Background

Ferroptosis plays an important role in a variety of disease processes and is equally important in pancreatic diseases. However, the role of ferroptosis-related genes (FRGs) in acute pancreatitis (AP) remains unknown, and their specific potential mechanisms still need to be explored extensively.

Methods

AP-related gene microarray data were obtained from the GEO database, while FRGs were obtained from the ferroptosis database (FerrDb). Differentially expressed genes (DEGs) were screened by the "limma" package, and GSEA was performed. The corresponding ferroptosis-related differentially expressed genes (FRDEGs) were screened, and GO and KEGG pathway analyses were performed. A PPI network was constructed to identify hub FRDEGs by CytoHubba, MCODE and CTD scores. Transcription factors and miRNAs predicted using the NetworkAnalyst database were used to establish the regulatory network. Immune cell infiltration analysis was performed by the R package "ssGSEA" algorithm. The hub genes were validated by transcriptome sequencing of AP model mice and immunohistochemistry in rats and mice.

Results

A total of 82 FRDEGs were screened, and these genes were mainly associated with ferroptosis, hypoxic response, autophagy, mitophagy and immune inflammation. However, we also found that these genes are also jointly involved in other cell death modalities, such as apoptosis and necroptosis. Further analysis obtained 7 hub genes from 82 genes, and single-sample gene set enrichment analysis (ssGSEA) showed that the hub genes are closely associated with the infiltration of specific immune cells and the activation of immune pathways.

Conclusion

This study reveals the complex functions and important roles of ferroptosis-related genes in AP and provides gene targets for further studies of AP.

Inhibition of angiotensin II type 1 receptor reduces oxidative stress damage to the intestinal barrier in severe acute pancreatitis

Intestinal barrier injury is a common complication of severe acute pancreatitis (SAP), which is often accompanied by intestinal mucosal barrier injury and results in serious consequences. However, the exact mechanism remains unclear. We aimed to investigate whether angiotensin II type 1 receptor (AT1)-mediated oxidative stress is involved in SAP intestinal barrier injury and assessed the effects of inhibiting this pathway. The SAP model was established by retrograde bile duct injection of sodium taurocholate (5%). The rats were divided into three groups: the control group (SO), the SAP group (SAP), and the azilsartan intervention group (SAP + AZL). Serum amylase, lipase, and other indexes were measured to evaluate SAP severity in each group. Histopathological changes in the pancreas and intestine were evaluated by HE staining. The oxidative stress of intestinal epithelial cells was detected by superoxide dismutase and glutathione. We also detected the expression and distribution of intestinal barrier-related proteins. The results showed that the serum indexes, the severity of tissue damage, and the level of oxidative stress in the SAP + AZL group were significantly lower than in the SAP group. Our study provided hitherto undocumented evidence of AT1 expression in the intestinal mucosa, confirming that AT1-mediated oxidative stress is involved in SAP intestinal mucosal injury, and inhibiting this pathway could effectively reduce intestinal mucosal oxidative stress injury, providing a new and effective target for the treatment of SAP intestinal barrier injury.

Elevation of HO-1 expression protects the intestinal mucosal barrier in severe acute pancreatitis via inhibition of the MLCK/p-MLC signaling pathway

In severe acute pancreatitis (SAP), intestinal mucosal barrier damage can cause intestinal bacterial translocation and induce or aggravate systemic infections. Heme oxygenase-1 (HO-1) is a validated antioxidant and cytoprotective agent. This research aimed to investigate the effect and mechanism of HO-1 on SAP-induced intestinal barrier damage in SAP rats. Healthy adult male Sprague-Dawley rats were randomly separated into the sham-operated group, SAP group, SAP + Hemin group, and SAP + Znpp group. The rat model of SAP was established by retrograde injection of sodium taurocholate (5%) into the biliopancreatic duct. Hemin (a potent HO-1 activator) and Znpp (a competitive inhibitor of HO-1) were injected intraperitoneally in the selected groups 24 h before SAP. Serum and intestinal tissue samples were collected for analysis after 24 h in each group. Hemin pretreatment significantly reduced systemic inflammation, intestinal oxidative stress, and intestinal epithelial apoptosis in SAP by increasing HO-1 expression. Meanwhile, pretreatment with Hemin abolished the inhibitory effect on the expression of the tight junction proteins and significantly inhibited the activation of the MLCK/P-MLC signaling pathway. Conversely, ZnPP completely reversed these effects. Our study indicates that upregulation of HO-1 expression attenuates the intestinal mucosal barrier damage in SAP. The protective effect of HO-1 on the intestine is attributed to MLCK/p-MLC signaling pathway inhibition.

Characterization of unconventional pathogenic Escherichia coli isolated from bloodstream infection: virulence beyond the opportunism

Extraintestinal pathogenic Escherichia coli (ExPEC) is the leading cause of urinary tract infection worldwide and a critical bloodstream infection agent. There are more than 50 virulence factors (VFs) related to ExPEC pathogenesis; however, many strains isolated from extraintestinal infections are devoid of these factors. Since opportunistic infections may occur in immunocompromised patients, E. coli strains that lack recognized VFs are considered opportunist, and their virulence potential is neglected. We assessed eleven E. coli strains isolated from bloodstream infections and devoid of the most common ExPEC VFs to understand their pathogenic potential. The strains were evaluated according to their capacity to interact in vitro with human eukaryotic cell lineages (Caco-2, T24, HEK293T, and A549 cells), produce type 1 fimbriae and biofilm in diverse media, resist to human sera, and be lethal to Galleria mellonella. One strain displaying all phenotypic traits was sequenced and evaluated. Ten strains adhered to Caco-2 (colon), eight to T24 (bladder), five to HEK-293 T (kidney), and four to A549 (lung) cells. Eight strains produced type 1 fimbriae, ten adhered to abiotic surfaces, nine were serum resistant, and seven were virulent in the G. mellonella model. Six of the eleven E. coli strains displayed traits compatible with pathogens, five of which were isolated from an immune-competent host. The genome of the EC175 strain, isolated from a patient with urosepsis, reveals that the strain belonged to ST504-A, and serotype O11:H11; harbors thirteen VFs genes, including genes encoding UpaG and yersiniabactin as the only ExPEC VFs identified. Together, our results suggest that the ExPEC pathotype includes pathogens from phylogroups A and B1, which harbor VFs that remain to be uncovered.

Ferroptosis in Rat Lung Tissue during Severe Acute Pancreatitis-Associated Acute Lung Injury: Protection of Qingyi Decoction

Qingyi decoction (QYD) has anti-inflammatory pharmacological properties and substantial therapeutic benefits on severe acute pancreatitis (SAP) in clinical practice. However, its protective mechanism against SAP-associated acute lung injury (ALI) remains unclear. In this study, we screened the active ingredients of QYD from the perspective of network pharmacology to identify its core targets and signaling pathways against SAP-associated ALI. Rescue experiments were used to determine the relationship between QYD and ferroptosis. Then, metabolomics and 16s rDNA sequencing were used to identify differential metabolites and microbes in lung tissue. Correlation analysis was utilized to explore the relationship between core targets, signaling pathways, metabolic phenotypes, and microbial flora, sorting out the potential molecular network of QYD against SAP-associated lung ALI. Inflammatory damage was caused by SAP in the rat lung. QYD could effectively alleviate lung injury, improve respiratory function, and significantly reduce serum inflammatory factor levels in SAP rats. Network pharmacology and molecular docking identified three key targets: ALDH2, AnxA1, and ICAM-1. Mechanistically, QYD may inhibit ferroptosis by promoting the ALDH2 expression and suppress neutrophil infiltration by blocking the cleavage of intact AnxA1 and downregulating ICAM-1 expression. Ferroptosis activator counteracts the pulmonary protective effect of QYD in SAP rats. In addition, seven significant differential metabolites were identified in lung tissues. QYD relatively improved the lung microbiome's abundance in SAP rats. Further correlation analysis determined the correlation between ferroptosis, differential metabolites, and differential microbes. In this work, the network pharmacology, metabolomics, and 16s rDNA sequencing were integrated to uncover the mechanism of QYD against SAP-associated ALI. This novel integrated method may play an important role in future research on traditional Chinese medicine.

FUT2-dependent fucosylation of HYOU1 protects intestinal stem cells against inflammatory injury by regulating unfolded protein response

The intestinal epithelial repair after injury is coordinated by intestinal stem cells (ISCs). Fucosylation catalyzed by fucosyltransferase 2 (FUT2) of the intestinal epithelium is beneficial to mucosal healing but poorly defined is the influence on ISCs. The dextran sulfate sodium (DSS) and lipopolysaccharide (LPS) model were used to assess the role of FUT2 on ISCs after injury. The apoptosis, function, and stemness of ISCs were analyzed using intestinal organoids from WT and Fut2^ΔISC (ISC-specific Fut2 knockout) mice incubated with LPS and fucose. N-glycoproteomics, UEA-1 chromatography, and site-directed mutagenesis were monitored to dissect the regulatory mechanism, identify the target fucosylated protein and the corresponding modification site. Fucose could alleviate intestinal epithelial damage via upregulating FUT2 and α-1,2-fucosylation of ISCs. Oxidative stress, mitochondrial dysfunction, and cell apoptosis were impeded by fucose. Meanwhile, fucose sustained the growth and proliferation capacity of intestinal organoids treated with LPS. Contrarily, FUT2 depletion in ISCs aggravated the epithelial damage and disrupted the growth and proliferation capacity of ISCs via escalating LPS-induced endoplasmic reticulum (ER) stress and initiating the IRE1/TRAF2/ASK1/JNK branch of unfolded protein response (UPR). Fucosylation of the chaperone protein HYOU1 at the N-glycosylation site of asparagine (Asn) 862 mediated by FUT2 was identified to facilitate ISCs survival and self-renewal, and improve ISCs resistance to ER stress and inflammatory injury. Our study highlights a fucosylation-dependent protective mechanism of ISCs against inflammation, which may provide a fascinating strategy for treating intestinal injury disorders.

Salidroside ameliorates severe acute pancreatitis-induced cell injury and pyroptosis by inactivating Akt/NF-κB and caspase-3/GSDME pathways

Our previous studies showed that Salidroside (Sal), a glucoside of the phenylpropanoid tyrosol isolated from Rhodiola rosea L, alleviated severe acute pancreatitis (SAP) by inhibiting inflammation. However, the detailed mechanism remains unclear. Recent evidence has indicated a critical role of Sal in ameliorating inflammatory disorders by regulating pyroptosis. The present study aimed to explore the involvement of Sal and pyroptosis in the pathogenesis of SAP and investigate the potential mechanism. The effects of Sal on pyroptosis were first evaluated using SAP rat and cell model. Our results revealed that Sal treatment significantly decreased SAP-induced pancreatic cell damage and pyroptosis in vivo and in vitro, as well as reduced the release of lactate dehydrogenase (LDH), IL-1β and IL-18. Search Tool for Interacting Chemicals (STITCH) online tool identified 4 genes (CASP3, AKT1, HIF1A and IL10) as candidate targets of Sal in both rattus norvegicus and homo sapiens. Western blot and immunohistochemistry staining validated that Sal treatment decreased the phosphorylation levels of Akt and NF-κB p65, as well as cleaved caspase-3 and N-terminal fragments of GSDME (GSDME-N), suggesting that Sal might suppress pyroptosis through inactivating Akt/NF-κB and Caspase-3/GSDME pathways. Furthermore, overexpression of AKT1 or CASP3 could partially reverse the inhibitory effects of Sal on cell injury and pyroptosis, while downregulation of AKT1 or CASP3 promoted the inhibitory effects of Sal. Taken together, our data indicate that Sal suppresses SAP-induced pyroptosis through inactivating Akt/NF-κB and Caspase-3/GSDME pathways.

Identification of AP-1 as a Critical Regulator of Glutathione Peroxidase 4 (GPX4) Transcriptional Suppression and Acinar Cell Ferroptosis in Acute Pancreatitis

Glutathione peroxidase 4 (GPX4)-dependent ferroptosis in pancreatic acinar cells plays a critical role in acute pancreatitis (AP). However, potential upstream regulators of GPX4 are not well defined. Here, we observed a marked reduction in acinar GPX4 expression and ferroptotic cell death in mice with cerulein-induced AP. To determine the critical factors involved in acinar cell ferroptosis, pancreas transcriptome data from an AP mouse model were analyzed and overlapped with predicted transcription factors of Gpx4, and an upregulated transcription factor active protein 1 (AP-1) protein, Jun, was identified. The administration of a specific ferroptosis inhibitor liproxstatin-1 alleviated AP pathology and significantly decreased Jun levels. Bioinformatic analysis indicated that the Gpx4 promoter contains a putative AP-1 binding site. Jun binds directly to the Gpx4 promoter and inhibits Gpx4 transcription under pancreatic conditions. AP-1 inhibition by a selective inhibitor SR11302 reversed GPX4 reduction and ameliorated AP pathology in a GPX4-dependent manner. Collectively, our study demonstrates that the downregulation of GPX4 by AP-1 is critical in the aggravation of acinar cell ferroptosis during the progression of AP. Strategies targeting the AP-1/GPX4 axis may be potentially effective for the prevention and treatment of AP.

Ferulic acid alleviates alveolar epithelial barrier dysfunction in sepsis-induced acute lung injury by activating the Nrf2/HO-1 pathway and inhibiting ferroptosis

CONTEXT

Ferulic acid (FA) has antioxidative and anti-inflammatory effects, and is a promising drug to treat sepsis.

OBJECTIVE

To study the therapeutic effect of FA in sepsis-induced acute lung injury (ALI) and its underlying mechanisms.

MATERIALS AND METHODS

The caecal ligation and puncture (CLP) manoeuvre was applied to establish a murine model of sepsis-induced ALI, and female BALB/c mice (6 mice per group) were subjected to 100 mg/kg FA or 0.8 mg/kg ferrostatin-1 (Fer-1, ferroptosis inhibitor) treatment to clarify the role of FA in preserving alveolar epithelial barrier function and inhibiting ferroptosis. Lipopolysaccharide (LPS; 500 ng/mL)-induced cell models were prepared and subjected to FA (0.1 μM), sh-Nrf2, and Fe (Fe-citrate, ferroptosis inducer; 5 M) treatment to study the in vitro effect of FA on LPS-induced alveolar epithelial cell injury and the role of the Nrf2/HO-1 pathway.

RESULTS

We found that FA decreased the lung injury score (48% reduction), lung wet/dry weight ratio (33% reduction), and myeloperoxidase activity (58% reduction) in sepsis-induced ALI. Moreover, FA inhibited ferroptosis of alveolar epithelial cells and improved alveolar epithelial barrier dysfunction. The protective role of FA against alveolar epithelial barrier dysfunction could be reversed by the ferroptosis inducer Fe-citrate, suggesting that FA alleviates alveolar epithelial barrier dysfunction by inhibiting ferroptosis. Mechanistically, we found that FA inhibited ferroptosis of alveolar epithelial cells by activating the Nrf2/HO-1 pathway.

CONCLUSION

Collectively, our data highlighted the alleviatory role of ferulic acid in sepsis-induced ALI by activating the Nrf2/HO-1 pathway and inhibiting ferroptosis, offering a new basis for sepsis treatment.

Mitochondrial regulatory mechanisms in spinal cord injury: A narrative review

Spinal cord injury is a severe central nervous system injury that results in the permanent loss of motor, sensory, and autonomic functions below the level of injury with limited recovery. The pathological process of spinal cord injury includes primary and secondary injuries, characterized by a progressive cascade. Secondary injury impairs the ability of the mitochondria to maintain homeostasis and leads to calcium overload, excitotoxicity, and oxidative stress, further exacerbating the injury. The defective mitochondrial function observed in these pathologies accelerates neuronal cell death and inhibits regeneration. Treatment of spinal cord injury by preserving mitochondrial biological function is a promising, although still underexplored, therapeutic strategy. This review aimed to explore mitochondrial-based therapeutic advances after spinal cord injury. Specifically, it briefly describes the characteristics of spinal cord injury. It then broadly discusses the drugs used to protect the mitochondria (e.g., cyclosporine A, acetyl-L-carnitine, and alpha-tocopherol), phenomena associated with mitochondrial damage processes (e.g., mitophagy, ferroptosis, and cuproptosis), mitochondrial transplantation for nerve cell regeneration, and innovative mitochondrial combined protection therapy.

Elevated serum ferritin levels are associated with severity and prognosis of severe acute pancreatitis: a preliminary cohort study

Background

Serum ferritin (SF), as an acute-phase response protein, is used to reflect the degree of oxidative stress and systemic inflammatory responses. This study was designed to assess the effect of elevated SF levels on the severity of acute pancreatitis (AP).

Methods

From January 2013 to December 2020, 200 consecutive patients with AP were retrospectively reviewed to analyze the relationships among the etiologies of pancreatitis, the severity of the disease and SF levels. The receiver operating characteristic (ROC) curve and logistic regression analysis were used to assess whether elevated SF levels could predict the onset of organ failure in AP.

Results

92 (46%) had high SF levels (> 275 ng/ml). SF levels were not associated with the etiology of AP disease. Among patients with high SF levels, there was a significant increase in the proportion of patients with severe AP (23.1% vs. 76.9%) and a higher proportion of systemic inflammatory response scores (25.9% vs. 44.6%) in comparison to patients with normal SF levels. The area under the ROC curve for SF in predicting persistent organ failure was 0.812 [95% confidence interval 0.721–0.904].

Conclusions

F concentrations were positively correlated with the severity of AP, and quantitative assessment of SF can predict disease severity and organ failure in patients with AP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02446-z.

Ferroptosis in sepsis: The mechanism, the role and the therapeutic potential

Sepsis is a common critical illness in the Intensive care unit(ICU) and its management and treatment has always been a major challenge in critical care medicine. The dysregulated host response to infection, causing systemic multi-organ and multi-system damage is the main pathogenesis. Notably, intense stress during sepsis can lead to metabolic disturbances of ions, lipids and energy in the organism. Ferroptosis is an iron-dependent, non-apoptotic cell death distinguished by a disruption of iron metabolism and iron-dependent accumulation of lipid peroxides. Mounting researches have established that ferroptosis has an essential part in anti-inflammatory and sepsis, and drugs targeting ferroptosis-related molecules, such as ferroptosis inhibitors, are gradually proving their effectiveness in sepsis. This paper summarizes and reviews the pathogenesis of ferroptosis, its regulatory network, and its vital involvement in the initiation of sepsis and related organ damage, and finally discusses the possible target drugs provided by the above mechanisms, describes the dilemmas as well as the outlook, in the hope of finding more links between ferroptosis and sepsis and providing new perspectives for the future treatment of sepsis.

Keratin 8 Is an Inflammation-Induced and Prognosis-Related Marker for Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the highest-grade malignancies in the world. More effective biomarkers and treatment plans are necessary to improve the diagnosis rate and clinical outcome. The oncogenesis of PDAC is influenced by several factors, including chronic pancreatitis (CP). Keratin 8 (KRT8) is an important member of the keratin protein family and plays a role in regulating the cellular response to stress stimuli and mediating inflammatory reactions. However, the role of KRT8 in pancreatitis and PDAC is still poorly understood. Here we assessed the differentially expressed genes (DEGs) by bioinformatic methods with expression profiles available online for a caerulein-induced mouse model and human PDAC tissue. The prognostic value was evaluated by Kaplan–Meier analysis and Cox regression analysis. The diagnostic value was evaluated by Receiver Operating Characteristic analysis (ROC). The function of the genes was predicted by protein-protein interaction analysis, correlation analysis, and GO analysis. The conclusion was further validated in rat pancreatitis model, human tissue, and PDAC cell lines, including immunohistochemical staining (IHC), CCK-8 assay, wound healing assay, and flow cytometry. KRT8 was found to be upregulated in murine pancreatitis tissue, human CP tissue, and human PDAC tissue. High expression of KRT8 had a negative impact on the prognosis of PDAC patients. KRT8 was predicted to be involved in the regulation of the migration and viability of PDAC cells, which was validated in PDAC cell lines. Knockdown of KRT8 impaired the migration and proliferation and induced apoptosis in PDAC cell lines. In conclusion, keratin 8 is an inflammation-induced molecule and could serve as a diagnostic and prognostic marker for PDAC patients. More studies are needed for further validation from the perspective of precision and individualized medicine.

UBIAD1 alleviates ferroptotic neuronal death by enhancing antioxidative capacity by cooperatively restoring impaired mitochondria and Golgi apparatus upon cerebral ischemic/reperfusion insult

Background

Neuronal death due to over-oxidative stress responses defines the pathology of cerebral ischemic/reperfusion (I/R) insult. Ferroptosis is a form of oxidative cell death that is induced by disruption of the balance between antioxidants and pro-oxidants in cells. However, the potential mechanisms responsible for cerebral I/R-induced ferroptotic neuronal death have not been conclusively determined. UBIAD1, is a newly identified antioxidant enzyme that catalyzes coenzyme Q10 (CoQ10) and vitamin K2 biosynthesis in the Golgi apparatus membrane and mitochondria, respectively. Even though UBIAD1 is a significant mediator of apoptosis in cerebral I/R challenge, its roles in ferroptotic neuronal death remain undefined. Therefore, we investigated whether ferroptotic neuronal death is involved in cerebral I/R injury. Further, we evaluated the functions and possible mechanisms of UBIAD1 in cerebral I/R-induced ferroptotic neuronal death, with a major focus on mitochondrial and Golgi apparatus dysfunctions.

Results

Ferroptosis occurred in cerebral I/R. Ferroptotic neuronal death promoted cerebral I/R-induced brain tissue injury and neuronal impairment. UBIAD1 was expressed in cerebral tissues and was localized in neurons, astrocytes, and microglia. Under cerebral I/R conditions overexpressed UBIAD1 significantly suppressed lipid peroxidation and ferroptosis. Moreover, upregulated UBIAD1 protected against brain tissue damage and neuronal death by alleviating I/R-mediated lipid peroxidation and ferroptosis. However, UBIAD1 knockdown reversed these changes. Enhanced UBIAD1-mediated ferroptosis elevated the antioxidative capacity by rescuing mitochondrial and Golgi apparatus dysfunction in cerebral I/R-mediated neuronal injury. They improved the morphology and biofunctions of the mitochondria and Golgi apparatus, thereby elevating the levels of SOD, T-AOC and production of CoQ10, endothelial nitric oxide synthase (eNOS)-regulated nitric oxide (NO) generation as well as suppressed MDA generation.

Conclusions

The neuroprotective agent, UBIAD1, modulates I/R-mediated ferroptosis by restoring mitochondrial and Golgi apparatus dysfunction in damaged brain tissues and neurons, thereby enhancing antioxidative capacities. Moreover, the rescue of impaired mitochondrial and Golgi apparatus as a possible mechanism of regulating ferroptotic neuronal death is a potential treatment strategy for ischemic stroke.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00776-9.