The complex interplay between endoplasmic reticulum stress and the NLRP3 inflammasome: a potential therapeutic target for inflammatory disorders

Unravelling the interplay between ER stress, UPR and the cGAS-STING pathway: Implications for osteoarthritis pathogenesis and treatment strategy

Osteoarthritis (OA) is a debilitating chronic degenerative disease affecting the whole joint organ leading to pain and disability. Cellular stress and injuries trigger inflammation and the onset of pathophysiological changes ensue after irreparable damage and inability to resolve inflammation, impeding the completion of the healing process. Extracellular matrix (ECM) degradation leads to dysregulated joint tissue metabolism. The reparative effort induces the proliferation of hypertrophic chondrocytes and matrix protein synthesis. Aberrant protein synthesis leads to endoplasmic reticulum (ER) stress and chondrocyte apoptosis with consequent cartilage matrix loss. These events in a vicious cycle perpetuate inflammation, hindering the restoration of normal tissue homeostasis. Recent evidence suggests that inflammatory responses and chondrocyte apoptosis could be caused by the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signalling axis in response to DNA damage. It has been reported that there is a crosstalk between ER stress and cGAS-STING signalling in cellular senescence and other diseases. Based on recent evidence, this review discusses the role of ER stress, Unfolded Protein Response (UPR) and cGAS-STING pathway in mediating inflammatory responses in OA.

Asiatic Acid Alleviates LPS-Induced Pyroptosis and Endoplasmic Reticulum Stress-Mediated Apoptosis via Inhibiting the HMGB1/TLR4/NF-κB Pathway in Broiler Hepatocytes

Lipopolysaccharides (LPS) is the major compoent of Gram-negative bacteria and an important factor in inducing inflammation, which usually leads to multiple organ failure in broilers, seriously affecting the growth performance of broilers and hindering the development of poultry farming. Under the policy of prohibiting antibiotics in feed, it has become more urgent to find natural drugs to prevent liver damage caused by LPS in broilers. Asiatic acid (AA) is a pentacyclic triterpene that has been proven to have anti-inflammatory and antioxidant effects. However, the protective effects of AA in LPS-induced liver damage in broilers still need to be clarified. This study aims to explore the complete mechanism of AA against LPS-induced acute liver injury (ALI) in broilers. A total of 60 broilers (1 day old) were randomly divided into the control group, LPS group, LPS+AA (15, 30 and 60 mg/kg) group and control+AA (60 mg/kg) group. At 16, 18 and 20 days of age, the broilers were attacked with LPS (0.5 mg/kg) to construct liver injury model. H&E staining assessed liver pathological changes. The mRNA and protein expression levels related to the HMGB1/TLR4/NF-κB pathway, pyroptosis, and ERS-mediated apoptosis in the liver tissue were detected. Our results founded that intraperitoneal injection of LPS in broilers increased the activities of AST and ALT, as well as raising the related gene and protein expression of the HMGB1/TLR4/NF-κB pathway, pyroptosis, and ERS-mediated apoptosis. Interestingly, AA improved LPS-induced liver damage and decreased the activities of AST and ALT in broilers. Additionally, AA mitigated LPS-induced ALI by reducing the mRNA levels and protein expressions of the HMGB1/TLR4/NF-κB pathway, pyroptosis and ERS-mediated apoptosis. In conclusion, the present study investigated that AA mitigated LPS-induced ALI in broilers by reducing pyroptosis and ERS-mediated apoptosis via inhibition of the HMGB1/TLR4/NF-κB pathway. Therefore, AA may serve as a potential feed additive for the prevention of LPS-induced ALI in broilers.

Aegeline attenuates TNBS-induced colitis by suppressing the NFƙB-mediated NLRP3 inflammasome pathway in mice

A chronic inflammatory condition of the intestine, ulcerative colitis (UC), is challenging to successfully manage once diagnosed. Currently, available medical therapies for UC exhibit minimal efficacy with unacceptable side effects, while inventive biological agents are expensive and yet not well accepted by patients. Discovering more effective and safer treatments to treat UC is therefore essential. One of the primary alkaloids found in Aegle marmelos, aegeline, has anti-inflammatory and antioxidant properties as well as being able to suppress several pro-inflammatory cytokines responsible for inflammation. The study aimed to investigate the effectiveness of aegeline in alleviating 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis through the NFƙB-mediated NLRP3 inflammasome pathway. Mice were randomly allocated into six groups, Normal control (NC), Model control (MC-TNBS, 2,4,6-trinitrobenzene sulfonic acid), STD (TNBS + sulfasalazine 100 mg/kg), AG1, AG2, and AG3 (TNBS + aegeline 5, 10, 20 mg/kg) respectively. Physical parameters such as a change in body weight, stool consistency, rectal bleeding, colon length, myeloperoxidase (MPO) levels and nitric oxide (NO) levels, and disease activity index (DAI) were assessed and supporting gene expression studies of various pro-inflammatory cytokines and enzymes were evaluated and histopathological changes observed. Administration of aegeline (10, 20 mg/kg) was found to be effective in colon protection by lowering the disease activity score and myeloperoxidase level and improving other physical parameters. Aegeline in high dose significantly downregulated the gene expression of NFƙB, iNOS, COX-2, NLRP3, IL-1β, and IL-18, conferring great anti-inflammatory potential. Suggestive of the findings, aegeline reduced the damage to the colon by downregulating transcriptional genes and enzymes leading to inflammation and mitigated TNBS-induced colitis probably through the NFƙB-mediated NLRP3 inflammasome pathway.

Emerging insights into the role of NLRP3 inflammasome and endoplasmic reticulum stress in renal diseases

NLRP3 inflammasome is a key component of the innate immune system, mediating the activation of caspase-1, and the maturity and secretion of the pro-inflammatory cytokine interleukin (IL)-1beta (IL-1β) and IL-18 to cope with microbial infections and cell injury. The NLRP3 inflammasome is activated by various endogenous danger signals, microorganisms and environmental stimuli, including urate, extracellular adenosine triphosphate (ATP) and cholesterol crystals. Increasing evidence indicates that the abnormal activation of NLRP3 is involved in multiple diseases including renal diseases. Hence, clarifying the mechanism of action of NLRP3 inflammasome in different diseases can help prevent and treat various diseases. Endoplasmic reticulum (ER) is an important organelle which participates in cell homeostasis maintenance and protein quality control. The unfolded protein response (UPR) and ER stress are caused by the excessive accumulation of unfolded or misfolded proteins in ER to recover ER homeostasis. Many factors can cause ER stress, including inflammation, hypoxia, environmental toxins, viral infections, glucose deficiency, changes in Ca2+ level and oxidative stress. The dysfunction of ER stress participates in multiple diseases, such as renal diseases. Many previous studies have shown that NLRP3 inflammasome and ER stress play an important role in renal diseases. However, the relevant mechanisms are not yet fully clear. Herein, we focus on the current understanding of the role and mechanism of ER stress and NLRP3 inflammasome in renal diseases, hoping to provide theoretical references for future related researches.

Recent progress of endoplasmic reticulum stress in the mechanism of atherosclerosis

The research progress of endoplasmic reticulum (ER) stress in atherosclerosis (AS) is of great concern. The ER, a critical cellular organelle, plays a role in important biological processes including protein synthesis, folding, and modification. Various pathological factors may cause ER stress, and sustained or excessive ER stress triggers the unfolded protein response, ultimately resulting in apoptosis and disease. Recently, researchers have discovered the importance of ER stress in the onset and advancement of AS. ER stress contributes to the occurrence of AS through different pathways such as apoptosis, inflammatory response, oxidative stress, and autophagy. Therefore, this review focuses on the mechanisms of ER stress in the development of AS and related therapeutic targets, which will contribute to a deeper understanding of the disease's pathogenesis and provide novel strategies for preventing and treating AS.

Preventive effects of prenatal administration of OM-85/BV on asthma and respiratory infection risk in the offspring: A review of animal models

Asthma is the most common chronic disease in childhood affecting the daily lives of many patients despite current treatment regimens. Therefore, the need for new therapeutic approaches is evident, where a primary prevention strategy is the ultimate goal. Studies of children born to mothers in farming environments have shown a lower risk of respiratory infections and asthma development. Already at birth, these newborns have demonstrated accelerated maturation and upregulation of host defense immune functions suggesting a prenatal transplacental training of the innate immune system through maternal microbial exposure. This mechanism could possibly be utilized to help prevent both respiratory infections and asthma in young children. Human studies exploring the potential preventative effects of pregnancy bacterial lysate treatment on asthma and respiratory infections are lacking, however, this has been studied in experimental studies using mice through administrations of the bacterial lysate OM-85. This review will present the current literature on the immunomodulatory effects relevant for respiratory infections and asthma in the offspring of mice treated with OM-85 throughout pregnancy. Further, the review will discuss the cellular and molecular mechanisms behind these effects. In conclusion, we found promising results of an accelerated immune competence and improved resistance to airway challenges as a result of prenatal bacterial lysate treatment that may pave the way for implementing this in human trials to prevent asthma and respiratory infections.

Nerolidol rescues hippocampal injury of diabetic rats through inhibiting NLRP3 inflammasome and regulation of MAPK/AKT pathway

Despite the observation of diabetes-induced brain tissue damage and impaired learning and memory, the underlying mechanism of damage remains elusive, and effective, targeted therapeutics are lacking. Notably, the NLRP3 inflammasome is highly expressed in the hippocampus of diabetic individuals. Nerolidol, a naturally occurring compound with anti-inflammatory and antioxidant properties, has been identified as a potential therapeutic option for metabolic disorders. However, the ameliorative capacity of nerolidol on diabetic hippocampal injury and its underlying mechanism remain unclear. Network pharmacology and molecular docking was used to predict the signaling pathways and therapeutic targets of nerolidol for the treatment of diabetes. Then established a diabetic rat model using streptozotocin (STZ) combined with a high-fat diet and nerolidol was administered. Morris water maze to assess spatial learning memory capacity. Hematoxylin and eosin and Nissl staining was used to detect neuronal damage in the diabetic hippocampus. Transmission electron microscopy was used to detect the extent of damage to mitochondria, endoplasmic reticulum (ER) and synapses. Immunofluorescence was used to detect GFAP, IBA1, and NLRP3 expression in the hippocampus. Western blot was used to detect apoptosis (Bcl-2, BAX, and Cleaved-Caspase-3); synapses (postsynaptic densifying protein 95, SYN1, and Synaptophysin); mitochondria (DRP1, OPA1, MFN1, and MFN2); ER (GRP78, ATF6, CHOP, and caspase-12); NLRP3 inflammasome (NLRP3, ASC, and caspase-1); inflammatory cytokines (IL-18, IL-1β, and TNF-α); AKT (P-AKT); and mitogen-activated protein kinase (MAPK) pathway (P-ERK, P-p38, and P-JNK) related protein expression. Network pharmacology showed that nerolidol's possible mechanisms for treating diabetes are the MAPK/AKT pathway and anti-inflammatory effects. Animal experiments demonstrated that nerolidol could improve blood glucose, blood lipids, and hippocampal neuronal damage in diabetic rats. Furthermore, nerolidol could improve synaptic, mitochondrial, and ER damage in the hippocampal ultrastructure of diabetic rats by potentially affecting synaptic, mitochondrial, and ER-related proteins. Further studies revealed that nerolidol decreased neuroinflammation, NLRP3 and inflammatory factor expression in hippocampal tissue while also decreasing MAPK pathway expression and enhancing AKT pathway expression. However, nerolidol improves hippocampal damage in diabetic rats cannot be shown to improve cognitive function. In conclusion, our study reveals for the first time that nerolidol can ameliorate hippocampal damage, neuroinflammation, synaptic, ER, and mitochondrial damage in diabetic rats. Furthermore, we suggest that nerolidol may inhibit NLRP3 inflammasome and affected the expression of MAPK and AKT. These findings provide a new experimental basis for the use of nerolidol to ameliorate diabetes-induced brain tissue damage and the associated disease.

Role and mechanism of endoplasmic reticulum stress and NLRP3 inflammasome in acute kidney injury

Acute kidney injury (AKI) is a common critical condition in clinical practice, characterized by a rapid decline in renal function within a short period. The pathogenesis of AKI is complex and has not been fully elucidated. In recent years, studies have found that the activation of endoplasmic reticulum stress (ERS) and the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome are closely related to the occurrence of AKI. When the kidneys is damaged, the internal environment of the kidney cells is disrupted, leading to the activation of ERS. Excessive ERS can induce apoptosis of renal cells, leading to the occurrence of AKI. Additionally, the NLRP3 inflammasome can mediate the recognition of endogenous and exogenous danger signal molecules by the host, subsequently activating caspase-1, pro-inflammatory cytokines such as IL-1β and IL-18, inducing inflammatory responses, and promoting apoptosis of renal cells. In animal models of AKI, the upregulation of ERS markers is often accompanied by increased expression levels of NLRP3 inflammasome-related proteins, indicating that ERS can regulate the activation process of the NLRP3 inflammasome. Clarifying the role and mechanism of ERS and NLRP3 inflammasome in AKI is expected to provide new insights for the prevention and treatment of AKI.

Insights into the influence of three types of sugar on goose fatty liver formation from endoplasmic reticulum stress (ERS)

This study analyzed the formation of goose fatty liver due to endoplasmic reticulum stress (ERS) caused by 3 types of sugar. Transcriptome analysis was performed for liver tissues from geese fed a traditional diet (maize flour), geese overfed with traditional diet, and geese overfed with diet supplemented with glucose, fructose, or sucrose. Correlation analysis of the liver tissue transcriptomes showed that differentially expressed genes (DEGs) involved in ERS were significantly negatively correlated with DEGs involved in inflammation response in the sucrose overfeeding group, and significantly positively correlated with the DEGs involved in lipid metabolism in fructose overfeeding group. Goose primary hepatocytes were isolated in vitro and then treated with glucose or fructose. Some were also treated with ERS inhibitor 4-phenylbutyric acid (4-PBA). In the hepatocytes, mRNA expression of X-Box Binding Protein 1 (XBP1), activating transcription factor 6 (AFT6) and glucose-regulated protein 78 (GRP78) genes increased in the two sugar groups (glucose and fructose), but were suppressed by adding 4-PBA. The mRNA expression data, protein kinase contents, and triglyceride (TG) and very low-density lipoprotein (VLDL) concentrations all suggest that ERS regulates lipid deposition induced by glucose and fructose via elevating lipid synthesis, inhibiting fatty acid oxidation, and decreasing lipid transportation. In conclusion, glucose, or fructose cause ERS and then ERS causes lipid deposition in goose primary hepatocytes. Three types of sugar cause lipid accumulation and then lipid accumulation prevents ERS during goose fatty liver formation, which suggests a potential mechanism protects goose livers from ERS. The different sugars may induce lipid deposition in different ways.

Organelle stress and alterations in interorganelle crosstalk during liver fibrosis

The synchronous functioning and quality control of organelles ensure cell survival and function and are essential for maintaining homeostasis. Prolonged exposure to stressors (viruses, bacteria, parasitic infections, alcohol, drugs) or genetic mutations often disrupt the functional integrity of organelles which plays a critical role in the initiation and progression of several diseases including chronic liver diseases. One of the most important pathologic consequences of chronic liver diseases is liver fibrosis, characterized by tissue scarring due to the progressive accumulation of extracellular matrix components. Left untreated, fibrosis may advance to life-threatening complications such as cirrhosis, hepatic decompensation, and HCC, which collectively accounts for ∼1 million deaths per year worldwide. Owing to the lack of treatment options that can regress or reverse cirrhosis, liver transplantation is currently the only available treatment for end-stage liver disease. However, the limited supply of usable donor organs, adverse effects of lifelong immunosuppressive regimes, and financial considerations pose major challenges and limit its application. Hence, effective therapeutic strategies are urgently needed. An improved understanding of the organelle-level regulation of fibrosis can help devise effective antifibrotic therapies focused on reducing organelle stress, limiting organelle damage, improving interorganelle crosstalk, and restoring organelle homeostasis; and could be a potential clinical option to avoid transplantation. This review provides a timely update on the recent findings and mechanisms covering organelle-specific dysfunctions in liver fibrosis, highlights how correction of organelle functions opens new treatment avenues and discusses the potential challenges to clinical application.

Linking NLRP3 inflammasome and pulmonary fibrosis: mechanistic insights and promising therapeutic avenues

Pulmonary fibrosis is a devastating disorder distinguished by redundant inflammation and matrix accumulation in the lung interstitium. The early inflammatory cascade coupled with recurring tissue injury orchestrates a set of events marked by perturbed matrix hemostasis, deposition of matrix proteins, and remodeling in lung tissue. Numerous investigations have corroborated a direct correlation between the NLR family pyrin domain-containing 3 (NLRP3) activation and the development of pulmonary fibrosis. Dysregulated activation of NLRP3 within the pulmonary microenvironment exacerbates inflammation and may incite fibrogenic responses. Nevertheless, the precise mechanisms through which the NLRP3 inflammasome elicits pro-fibrogenic responses remain inadequately defined. Contemporary findings suggest that the pro-fibrotic consequences stemming from NLRP3 signaling primarily hinge on the action of interleukin-1β (IL-1β). IL-1β instigates IL-1 receptor signaling, potentiating the activity of transforming growth factor-beta (TGF-β). This signaling cascade, in turn, exerts influence over various transcription factors, including SNAIL, TWIST, and zinc finger E-box-binding homeobox 1 (ZEB 1/2), which collectively foster myofibroblast activation and consequent lung fibrosis. Here, we have connected the dots to illustrate how the NLRP3 inflammasome orchestrates a multitude of signaling events, including the activation of transcription factors that facilitate myofibroblast activation and subsequent lung remodeling. In addition, we have highlighted the prominent role played by various cells in the formation of myofibroblasts, the primary culprit in lung fibrosis. We also provided a concise overview of various compounds that hold the potential to impede NLRP3 inflammasome signaling, thus offering a promising avenue for the treatment of pulmonary fibrosis.

A bibliometric analysis of cardiomyocyte apoptosis from 2014 to 2023: A review

Cardiomyocyte apoptosis is an important factor in cardiac function decline observed in various cardiovascular diseases. To understand the progress in the field of cardiomyocyte apoptosis research, this paper uses bibliometrics to statistically analyze publications in this field. A total of 5939 articles were retrieved from the core Web of Science database, and then VOSviewer and Citespace were used to conduct a scientometric analysis of the authors, countries, institutions, references and keywords included in the articles to determine the cooperative relationships between researchers that study cardiomyocyte apoptosis. At present, the research hotspots in this field mainly include experimental research, molecular mechanisms, pathophysiology and cardiac regeneration of cardiomyocyte apoptosis-related diseases. NOD-like receptor thermal protein domain associated protein 3 inflammasome, circular RNA, and sepsis are the research frontiers in this field and are emerging as new areas of research focus. This work provides insight into research directions and the clinical application value for the continued advancement of cardiomyocyte apoptosis research.

Prdx6 Regulates Nlrp3 Inflammasome Activation-Driven Inflammatory Response in Lens Epithelial Cells

The continuum of antioxidant response dysregulation in aging/oxidative stress-driven Nlrp3 inflammasome activation-mediated inflammatory response is associated with age-related diseases. Peroxiredoxin (Prdx) 6 is a key antioxidant that provides cytoprotection by regulating redox homeostasis. Herein, using lens epithelial cells (LECs) derived from the targeted inactivation of Prdx6 gene and aging lenses, we present molecular evidence that Prdx6-deficiency causes oxidative-driven Nlrp3 inflammasome activation, resulting in pyroptosis in aging/redox active cells wherein Prdx6 availability offsets the inflammatory process. We observed that Prdx6-/- and aging LECs harboring accumulated reactive oxygen species (ROS) showed augmented activation of Nlrp3 and bioactive inflammatory components, like Caspase-1, IL-1β, ASC and Gasdermin-D. Similar to lipopolysaccharide treatment, oxidative exposure led to further ROS amplification with increased activation of the Nlrp3 inflammasome pathway. Mechanistically, we found that oxidative stress enhanced Kruppel-like factor 9 (Klf9) expression in aging/Prdx6-/- mLECs, leading to a Klf9-dependent increase in Nlrp3 transcription, while the elimination of ROS by the delivery of Prdx6 or by silencing Klf9 prevented the inflammatory response. Altogether, our data identify the biological significance of Prdx6 as an intrinsic checkpoint for regulating the cellular health of aging or redox active LECs and provide opportunities to develop antioxidant-based therapeutic(s) to prevent oxidative/aging-related diseases linked to aberrant Nlrp3 inflammasome activation.

CARMA3 Deficiency Aggravates Angiotensin II-Induced Abdominal Aortic Aneurysm Development Interacting Between Endoplasmic Reticulum and Mitochondria

BACKGROUND

Abdominal aortic aneurysm (AAA) is life threatening and associated with vascular walls' chronic inflammation. However, a detailed understanding of the underlying mechanisms is yet to be elucidated. CARMA3 assembles the CARMA3-BCL10-MALT1 (CBM) complex in inflammatory diseases and is proven to mediate angiotensin II (Ang II) response to inflammatory signals by modulating DNA damage-induced cell pyroptosis. In addition, interaction between endoplasmic reticulum (ER) stress and mitochondrial damage is one of the main causes of cell pyroptosis.

METHODS

Male wild type (WT) or CARMA3-/- mice aged 8 to 10 weeks were subcutaneously implanted with osmotic minipumps, delivering saline or Ang II at the rate of 1 μg/kg/min for 1, 2, and 4 weeks.

RESULTS

We discovered that CARMA3 knockout promoted formation of AAA and prominently increased diameter and severity of the mice abdominal aorta infused with Ang II. Moreover, a significant increase in the excretion of inflammatory cytokines, expression levels of matrix metalloproteinases (MMPs) and cell death was found in the aneurysmal aortic wall of CARMA3-/- mice infused with Ang II compared with WT mice. Further studies found that the degree of ER stress and mitochondrial damage in the abdominal aorta of CARMA3-/- mice was more severe than that in WT mice. Mechanistically, CARMA3 deficiency exacerbates the interaction between ER stress and mitochondrial damage by activating the p38MAPK pathway, ultimately contributing to the pyroptosis of vascular smooth muscle cells (VSMCs).

CONCLUSIONS

CARMA3 appears to play a key role in AAA formation and might be a potential target for therapeutic interventions of AAA.

Role of the ER-induced UPR pathway, apoptosis, and autophagy in colorectal cancer

When large amounts of misfolded or unfolded proteins accumulate in the endoplasmic reticulum (ER) in response to stress, a process called unfolded protein response (UPR) is activated. The disruption of this process leads to many diseases including diabetes, neurodegenerative diseases, and many cancers. In the process of UPR in response to stress and unfolded proteins, specific signaling pathways are induced in the endoplasmic reticulum and subsequently transmitted to the nucleus and cytoplasm, causing homeostasis and restoring the cell's normal condition with reducing protein translation and synthesis. The UPR response followed by stress enhancement balances cell survival with death, therefore in this condition cells decide either to survive or have the path of apoptosis ahead. However, in some cases, this balance is disturbed and the UPR pathway is chronically activated or not activated and the cell conditions lead to cancer. This study aimed to briefly investigate the association between ER stress, UPR, apoptosis, and autophagy in colorectal cancer (CRC). Moreover, in current study, we will try to demonstrate canonical ways and methods for the treatment of CRC cells with attenuated ER stress.

Fisetin derivatives exhibit enhanced anti-inflammatory activity and modulation of endoplasmic reticulum stress

Inflammation and endoplasmic reticulum (ER) stress are often hand in hand in the context of chronic disease. Both are activated upon perceived disturbances in homeostasis, being deleterious when intensely or chronically activated. Fisetin (FST) is a dietary flavonol that is known to possess multiple relevant bioactivities, raising the question of its potential health benefits and even its use in novel pharmacological approaches against ER stress and inflammation. To attain this prospect, some limitations to this molecule, namely its poor bioavailability and solubility, must be addressed. In an attempt to improve the biological properties of the parent molecule, we have synthesized a set of FST derivatives. These new molecules were tested along with the original compound for their ability to mitigate the activation of the signaling pathways underlying inflammation and ER stress. By reducing LPS-induced nuclear factor-kappa B (NF-κB) activation, cytokine release, inflammasome activation and reactive oxygen species (ROS) generation, FST has proven to be effective against the onset of inflammation. The molecule also decreases the activation of the unfolded protein response (UPR), as evidenced by the reduced expression of relevant UPR-related genes upon ER stress induction. Some of the tested derivatives are novel inhibitors of targets associated to inflammation and ER stress signaling, in some cases more potent than the parent compound. Furthermore, the reduced cytotoxicity of some of these molecules enabled the use of higher concentrations than that of FST, resulting in the observation of enhanced bioactivities.

IL11 activates the placental inflammasome to drive preeclampsia

Introduction

Preeclampsia is a life-threatening disorder of pregnancy unique to humans. Interleukin (IL)11 is elevated in serum from pregnancies that subsequently develop early-onset preeclampsia and pharmacological elevation of IL11 in pregnant mice causes the development of early-onset preeclampsia-like features (hypertension, proteinuria, and fetal growth restriction). However, the mechanism by which IL11 drives preeclampsia is unknown.

Method

Pregnant mice were administered PEGylated (PEG)IL11 or control (PEG) from embryonic day (E)10-16 and the effect on inflammasome activation, systolic blood pressure (during gestation and at 50/90 days post-natal), placental development, and fetal/post-natal pup growth measured. RNAseq analysis was performed on E13 placenta. Human 1^st trimester placental villi were treated with IL11 and the effect on inflammasome activation and pyroptosis identified by immunohistochemistry and ELISA.

Result

PEGIL11 activated the placental inflammasome causing inflammation, fibrosis, and acute and chronic hypertension in wild-type mice. Global and placental-specific loss of the inflammasome adaptor protein Asc and global loss of the Nlrp3 sensor protein prevented PEGIL11-induced fibrosis and hypertension in mice but did not prevent PEGIL11-induced fetal growth restriction or stillbirths. RNA-sequencing and histology identified that PEGIL11 inhibited trophoblast differentiation towards spongiotrophoblast and syncytiotrophoblast lineages in mice and extravillous trophoblast lineages in human placental villi.

Discussion

Inhibition of ASC/NLRP3 inflammasome activity could prevent IL11-induced inflammation and fibrosis in various disease states including preeclampsia.

Forsythiaside A alleviates Lipopolysacchrride-induced acute liver Injury through inhibiting endoplasmic reticulum stress and NLRP3 inflammasome activation

The liver is the primary site of inflammation caused by bacterial endotoxins in sepsis, and septic acute liver injury (SALI) is usually associated with poor outcomes in sepsis. Forsythiaside A (FTA), an active constituent of Forsythia suspensa, has been reported to have anti-inflammatory properties, antioxidant properties, and protective properties against neuroinflammation, sepsis, and edema.Therefore, the purpose of the present study was to examine FTA's potential effects on lipopolysaccharide (LPS)-induced SALI in mice.Our results indicated that pretreatment with FTA significantly attenuated aspartate aminotransferase (AST) and aminoleucine transferase (ALT) levels in plasma, ameliorated histopathological damage, inhibited hepatocyte apoptosis, diminished the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in the liver from mice exposed to LPS. Furthermore, our data showed that the administration of LPS resulted in robust endoplasmic reticulum (ER) stress response, as evidenced by GRP78 upregulation, p-PERK activation, elF2α phosphorylation, and ATF4 and CHOP overexpression in the liver. This, in turn, led to nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome activation, including the cleavage of caspase-1, secretion of IL-1β, and pyroptotic cell death in the liver specimens. Importantly, the ER stress response induced by the LPS challenge was blocked by FTA administration. Correspondingly, NLRP3 inflammasome activation was significantly ameliorated by the pretreatment with FTA. Thus, we demonstrated that FTA pretreatment could protect mice from LPS-induced SALI, and its protective effects were possibly mediated by inhibiting ER stress response and subsequent NLRP3 inflammasome activation.

The endoplasmic reticulum participated in drug metabolic toxicity

Covalent binding of reactive metabolites formed by drug metabolic activation with biological macromolecules is considered to be an important mechanism of drug metabolic toxicity. Recent studies indicate that the endoplasmic reticulum (ER) could play an important role in drug toxicity by participating in the metabolic activation of drugs and could be a primarily attacked target by reactive metabolites. In this article, we summarize the generation and mechanism of reactive metabolites in ER stress and their associated cell death and inflammatory cascade, as well as the systematic modulation of unfolded protein response (UPR)-mediated adaptive pathways.

Identification of immune-related endoplasmic reticulum stress genes in sepsis using bioinformatics and machine learning

Background

Sepsis-induced apoptosis of immune cells leads to widespread depletion of key immune effector cells. Endoplasmic reticulum (ER) stress has been implicated in the apoptotic pathway, although little is known regarding its role in sepsis-related immune cell apoptosis. The aim of this study was to develop an ER stress-related prognostic and diagnostic signature for sepsis through bioinformatics and machine learning algorithms on the basis of the differentially expressed genes (DEGs) between healthy controls and sepsis patients.

Methods

The transcriptomic datasets that include gene expression profiles of sepsis patients and healthy controls were downloaded from the GEO database. The immune-related endoplasmic reticulum stress hub genes associated with sepsis patients were identified using the new comprehensive machine learning algorithm and bioinformatics analysis which includes functional enrichment analyses, consensus clustering, weighted gene coexpression network analysis (WGCNA), and protein-protein interaction (PPI) network construction. Next, the diagnostic model was established by logistic regression and the molecular subtypes of sepsis were obtained based on the significant DEGs. Finally, the potential diagnostic markers of sepsis were screened among the significant DEGs, and validated in multiple datasets.

Results

Significant differences in the type and abundance of infiltrating immune cell populations were observed between the healthy control and sepsis patients. The immune-related ER stress genes achieved strong stability and high accuracy in predicting sepsis patients. 10 genes were screened as potential diagnostic markers for sepsis among the significant DEGs, and were further validated in multiple datasets. In addition, higher expression levels of SCAMP5 mRNA and protein were observed in PBMCs isolated from sepsis patients than healthy donors (n = 5).

Conclusions

We established a stable and accurate signature to evaluate the diagnosis of sepsis based on the machine learning algorithms and bioinformatics. SCAMP5 was preliminarily identified as a diagnostic marker of sepsis that may affect its progression by regulating ER stress.

Polyphenols, flavonoids and inflammasomes: the role of cigarette smoke in COPD

COPD is predicted to become the third leading cause of morbidity and mortality worldwide by 2030. Cigarette smoking (active or passive) is one of its chief causes, with about 20% of cigarette smokers developing COPD from cigarette smoke (CS)-induced irreversible damage and sustained inflammation of the airway epithelium. Inflammasome activation leads to the cleavage of pro-interleukin (IL)-1β and pro-IL-18, along with the release of pro-inflammatory cytokines via gasdermin D N-terminal fragment membrane pores, which further triggers acute phase pro-inflammatory responses and concurrent pyroptosis. There is currently intense interest in the role of nucleotide-binding oligomerisation domain-like receptor family, pyrin domain containing protein-3 inflammasomes in chronic inflammatory lung diseases such as COPD and their potential for therapeutic targeting. Phytochemicals including polyphenols and flavonoids have phyto-medicinal benefits in CS-COPD. Here, we review published articles from the last decade regarding the known associations between inflammasome-mediated responses and ameliorations in pre-clinical manifestations of CS-COPD via polyphenol and flavonoid treatment, with a focus on the underlying mechanistic insights. This article will potentially assist the development of drugs for the prevention and therapy of COPD, particularly in cigarette smokers.

This review compiles current investigations into the role of polyphenols/flavonoids in the alleviation of cigarette smoke-induced inflammasome; notably it provides a promising hit for rectifying the treatment of COPD.https://bit.ly/36OcUO9

The Inflammasome NLR Family Pyrin Domain-Containing Protein 3 (NLRP3) as a Novel Therapeutic Target for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a dramatic disease without cure. The US Food and Drug Administration-approved drugs, pirfenidone and nintedanib, only slow disease progression. The clinical investigation of novel therapeutic approaches for IPF is an unmet clinical need. Nucleotide-binding oligomerization domain-like receptor or NOD-like receptors are pattern recognition receptors capable of binding a large variety of stress factors. NLR family pyrin domain-containing protein 3 (NLRP3), once activated, promotes IL-1β, IL-18 production, and innate immune responses. Multiple reports indicate that the inflammasome NLRP3 is overactivated in IPF patients, leading to increased production of class I IL and collagens. Similarly, data from animal models of pulmonary fibrosis confirm the role of NLRP3 in the development of chronic lung injury and pulmonary fibrosis. This report provides a review of the evidence of NLRP3 activation in IPF and of NLRP3 inhibition in different animal models of fibrosis, and highlights the recent advances in direct and indirect NLRP3 inhibitors.

Endoplasmic Reticulum Stress and Its Role in Homeostasis and Immunity of Central and Peripheral Neurons

Neuronal cells are specialists for rapid transfer and translation of information. Their electrical properties relay on a precise regulation of ion levels while their communication via neurotransmitters and neuropeptides depends on a high protein and lipid turnover. The endoplasmic Reticulum (ER) is fundamental to provide these necessary requirements for optimal neuronal function. Accumulation of misfolded proteins in the ER lumen, reactive oxygen species and exogenous stimulants like infections, chemical irritants and mechanical harm can induce ER stress, often followed by an ER stress response to reinstate cellular homeostasis. Imbedded between glial-, endothelial-, stromal-, and immune cells neurons are constantly in communication and influenced by their local environment. In this review, we discuss concepts of tissue homeostasis and innate immunity in the central and peripheral nervous system with a focus on its influence on ER stress, the unfolded protein response, and implications for health and disease.

Cyanidin-3-O-Glucoside Ameliorates Palmitic-Acid-Induced Pancreatic Beta Cell Dysfunction by Modulating CHOP-Mediated Endoplasmic Reticulum Stress Pathways

Cyanidin-3-O-glucoside (C3G) is a natural colorant with anti-diabetic properties, while its underlying mechanisms remain far from clear. Here, we investigated the protective role of C3G on palmitic acid (PA)-induced pancreatic beta cell dysfunction and further decipher its possible molecular mechanisms. Both primary isolated mouse islets and the INS-1E cell were used, and treated with a mixture of PA (0.5 mM) and C3G (12.5 µM, 25 µM, 50 µM) for different durations (12, 24, 48 h). We found that C3G could dose-dependently ameliorate beta cell secretory function and further alleviate cell apoptosis. Mechanistically, the primary role of the PKR-like ER kinase (PERK) endoplasmic reticulum (ER) stress pathway was detected by RNA sequencing, and the PERK-pathway-related protein expression, especially the pro-apoptotic marker C/EBP homologous protein (CHOP) expression, was significantly downregulated by C3G treatment. The critical role of CHOP in mediating the protective effect of C3G was further validated by small interfering RNA. Conclusively, C3G could ameliorate PA-induced pancreatic beta cell dysfunction targeting the CHOP-related ER stress pathway, which might be used as a nutritional intervention for the preservation of beta cell dysfunction in type 2 diabetes mellitus.

Icariin attenuates ischemic stroke through suppressing inflammation mediated by endoplasmic reticulum stress signaling pathway in rats

Ischemic stroke possesses the characteristics of high incidence, high disability, and high mortality. Icariin (ICA) is a flavonoid extracted from the traditional Chinese medicine Epimedium. The protective effect of ICA on ischemic stroke is worthy to be further studied. In this study, male Sprague-Dawley rats were randomly divided into the following seven groups: sham, model, ICA low-dose (10 mg/kg), ICA medium-dose (20 mg/kg), ICA high-dose (40 mg/kg), positive control drug (12 mg/kg nimodipine) and endoplasmic reticulum stress induction (0.16 mg/kg tunicamycin) groups. The model of cerebral ischemia-reperfusion injury in the rats, including 2 h ischemia and 24 h reperfusion, was accomplished by applying the method of transient middle cerebral artery occlusion (MCAO). At 24 h reperfusion, neurological deficits, brain water content, pathological damage of brain tissues, the expression of inflammation-related targets, and the signal pathway-related proteins were explored. Compared with the model group, ICA significantly improved neurological deficits, brain edema and pathological damage after MCAO. In addition, ICA increased neuron survival, reduced microglial activation and expression of IL-1β, alleviating the inflammatory damage caused by ischemic stroke. Moreover, ICA suppressed the expressions of glucose-regulated protein 78 (GRP78), inositol requiring enzyme-1 α (IRE1α), phospho-IRE1α (p-IRE1α), protein kinase RNA-like ER kinase (PERK), phospho-PERK (p-PERK), spliced XBP1 (XBP1s), unspliced XBP1 (XBP1u), thioredoxin-interacting protein (TXNIP), NLRP3, and caspase-1. These results suggested that ICA offers neuroprotection against ischemic stroke by inhibiting ER stress-mediated inflammation. This article is protected by copyright. All rights reserved.

Involvement of Inflammasome Components in Kidney Disease

Inflammasomes are multiprotein complexes with an important role in the innate immune response. Canonical activation of inflammasomes results in caspase-1 activation and maturation of cytokines interleukin-1β and -18. These cytokines can elicit their effects through receptor activation, both locally within a certain tissue and systemically. Animal models of kidney diseases have shown inflammasome involvement in inflammation, pyroptosis and fibrosis. In particular, the inflammasome component nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) and related canonical mechanisms have been investigated. However, it has become increasingly clear that other inflammasome components are also of importance in kidney disease. Moreover, it is becoming obvious that the range of molecular interaction partners of inflammasome components in kidney diseases is wide. This review provides insights into these current areas of research, with special emphasis on the interaction of inflammasome components and redox signalling, endoplasmic reticulum stress, and mitochondrial function. We present our findings separately for acute kidney injury and chronic kidney disease. As we strictly divided the results into preclinical and clinical data, this review enables comparison of results from those complementary research specialities. However, it also reveals that knowledge gaps exist, especially in clinical acute kidney injury inflammasome research. Furthermore, patient comorbidities and treatments seem important drivers of inflammasome component alterations in human kidney disease.

GDF11 alleviates neointimal hyperplasia in a rat model of artery injury by regulating endothelial NLRP3 inflammasome activation and rapid re-endothelialization

Background

Neointimal hyperplasia induced by interventional surgery can lead to progressive obliteration of the vascular lumen, which has become a major factor affecting prognosis. The rate of re-endothelialization is known to be inversely related to neointima formation. Growth differentiation factor 11 (GDF11) is a secreted protein with anti-inflammatory, antioxidant, and antiaging properties. Recent reports have indicated that GDF11 can improve vascular remodeling by maintaining the differentiated phenotypes of vascular smooth muscle cells. However, it is not known whether and how GDF11 promotes re-endothelialization in vascular injury. The present study was performed to clarify the influence of GDF11 on re-endothelialization after vascular injury.

Methods

An adult Sprague–Dawley rat model of common carotid artery balloon dilatation injury was surgically established. A recombinant adenovirus carrying GDF11 was delivered into the common carotid artery to overexpress GDF11. Vascular re-endothelialization and neointima formation were assessed in harvested carotid arteries through histomolecular analysis. CCK-8 analysis, LDH release and Western blotting were performed to investigate the effects of GDF11 on endothelial NLRP3 inflammasome activation and relevant signaling pathways in vitro.

Results

GDF11 significantly enhanced re-endothelialization and reduced neointima formation in rats with balloon-dilatation injury by suppressing the activation of the NLRP3 inflammasome. Administration of an endoplasmic reticulum stress (ER stress) inhibitor, 4PBA, attenuated endothelial NLRP3 inflammasome activation induced by lysophosphatidylcholine. In addition, upregulation of LOX-1 expression involved elevated ER stress and could result in endothelial NLRP3 inflammasome activation. Moreover, GDF11 significantly inhibited NLRP3 inflammasome-mediated endothelial cell pyroptosis by negatively regulating LOX-1-dependent ER stress.

Conclusions

We conclude that GDF11 improves re-endothelialization and can attenuate vascular remodeling by reducing endothelial NLRP3 inflammasome activation. These findings shed light on new treatment strategies to promote re-endothelialization based on GDF11 as a future target.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03229-6.

AIM2 inflammasome contributes to aldosterone-induced renal injury via endoplasmic reticulum stress

Inflammatory response and renal fibrosis are the hallmarks of chronic kidney disease (CKD). However, the specific mechanism of aldosterone-induced renal injury in the progress of CKD requires elucidation. Emerging evidence has demonstrated that absent in melanoma 2 (AIM2)-mediated inflammasome activation and endoplasmic reticulum stress (ERS) play a pivotal role in the renal fibrosis. Here, we investigated whether overexpression or deficiency of AIM2 affects ERS and fibrosis in aldosterone-infused renal injury. Interestingly, we found that AIM2 was markedly expressed in the diseased proximal tubules from human and experimental CKD. Mechanically, overactivation of AIM2 aggravated aldosterone-induced ERS and fibrotic changes in vitro while knockdown of AIM2 blunted these effects in vivo and in vitro. By contrast, AIM2 deficiency ameliorated renal structure and function deterioration, decreased proteinuria levels and lowered systolic blood pressure in vivo; silencing of AIM2 blocked inflammasome-mediated signaling pathway, relieved ERS and fibrotic changes in vivo. Furthermore, mineralocorticoid receptor (MR) antagonist eplerenone and ERS inhibitor tauroursodeoxycholic acid (TUDCA) had nephroprotective effects on the basis of AIM2 overactivation in vitro, while they failed to produce a more remarkable renoprotective effect on the treatment of AIM2 silence in vitro. Notably, the combination of TUDCA with AIM2 knockdown significantly reduced proteinuria levels in vivo. Additionally, immunofluorescence assay identified that apoptosis-associated speck-like protein (ASC) recruitment and Gasdermin-D (GSDMD) cleavage respectively occurred in the glomeruli and tubules in vivo. These findings establish a crucial role for AIM2 inflammasome in aldosterone-induced renal injury, which may provide a novel therapeutic target for the pathogenesis of CKD.

AGEs-Induced and Endoplasmic Reticulum Stress/Inflammation-Mediated Regulation of GLUT4 Expression and Atherogenesis in Diabetes Mellitus

In recent decades, complex and exquisite pathways involved in the endoplasmic reticulum (ER) and inflammatory stress responses have been demonstrated to participate in the development and progression of numerous diseases, among them diabetes mellitus (DM). In those pathways, several players participate in both, reflecting a complicated interplay between ER and inflammatory stress. In DM, ER and inflammatory stress are involved in both the pathogenesis of the loss of glycemic control and the development of degenerative complications. Furthermore, hyperglycemia increases the generation of advanced glycation end products (AGEs), which in turn refeed ER and inflammatory stress, contributing to worsening glycemic homeostasis and to accelerating the development of DM complications. In this review, we present the current knowledge regarding AGEs-induced and ER/inflammation-mediated regulation of the expression of GLUT4 (solute carrier family 2, facilitated glucose transporter member 4), as a marker of glycemic homeostasis and of cardiovascular disease (CVD) development/progression, as a leading cause of morbidity and mortality in DM.

The Crucial Role of NLRP3 Inflammasome in Viral Infection-Associated Fibrosing Interstitial Lung Diseases

Idiopathic pulmonary fibrosis (IPF), one of the most common fibrosing interstitial lung diseases (ILD), is a chronic-age-related respiratory disease that rises from repeated micro-injury of the alveolar epithelium. Environmental influences, intrinsic factors, genetic and epigenetic risk factors that lead to chronic inflammation might be implicated in the development of IPF. The exact triggers that initiate the fibrotic response in IPF remain enigmatic, but there is now increasing evidence supporting the role of chronic exposure of viral infection. During viral infection, activation of the NLRP3 inflammasome by integrating multiple cellular and molecular signaling implicates robust inflammation, fibroblast proliferation, activation of myofibroblast, matrix deposition, and aberrant epithelial-mesenchymal function. Overall, the crosstalk of the NLRP3 inflammasome and viruses can activate immune responses and inflammasome-associated molecules in the development, progression, and exacerbation of IPF.

Infection and autoinflammation in inborn errors of immunity: brothers in arms

The binary view of inborn errors of immunity classified as either autoinflammatory conditions or primary immunodeficiency in the strict sense, that is, increased susceptibility to infection is challenged by the description of recent inborn errors of immunity (IEI) triggers leading to activation and disruption of cell death pathways, play a major part in the pathophysiology of infection and autoinflammation. In addition, molecules with a double role in the extracellular versus intracellular milieu add to the complexity. In all, in-depth study of human inborn errors of immunity will continue to instruct us on fundamental immunology and lead to novel therapeutic targets and approaches that can be used in other monogenic and polygenic/complex immune disorders.

Streptolysins are the primary inflammasome activators in macrophages during Streptococcus pyogenes infection

Group A Streptococcus (GAS) is a Gram-positive bacterial pathogen that causes an array of infectious diseases in humans. Accumulating clinical evidence suggests that proinflammatory interleukin (IL)-1β signaling plays an important role in GAS disease progression. The host regulates the production and secretion of IL-1β via the cytosolic inflammasome pathway. Activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome complex requires two signals: a priming signal that stimulates increased transcription of genes encoding the components of the inflammasome pathway, and an activating signal that induces assembly of the inflammasome complex. Here we show that GAS-derived lipoteichoic acid can provide a priming signal for NLRP3 inflammasome activation. As only few GAS-derived proteins have been associated with inflammasome-dependent IL-1β signaling, we investigated novel candidates that might play a role in activating the inflammasome pathway by infecting mouse bone marrow-derived macrophages and human THP-1 macrophage-like cells with a panel of isogenic GAS mutant strains. We found that the cytolysins streptolysin O (SLO) and streptolysin S are the main drivers of IL-1β release in proliferating logarithmic phase GAS. Using a mutant form of recombinant SLO, we confirmed that bacterial pore formation on host cell membranes is a key mechanism required for inflammasome activation. Our results suggest that streptolysins are major determinants of GAS-induced inflammation and present an attractive target for therapeutic intervention.

Autophagy and Mitophagy-Related Pathways at the Crossroads of Genetic Pathways Involved in Familial Sarcoidosis and Host-Pathogen Interactions Induced by Coronaviruses

Sarcoidosis is a multisystem disease characterized by the development and accumulation of granulomas, the hallmark of an inflammatory process induced by environmental and/or infectious and or genetic factors. This auto-inflammatory disease mainly affects the lungs, the gateway to environmental aggressions and viral infections. We have shown previously that genetic predisposition to sarcoidosis occurring in familial cases is related to a large spectrum of pathogenic variants with, however, a clustering around mTOR (mammalian Target Of Rapamycin)-related pathways and autophagy regulation. The context of the COVID-19 pandemic led us to evaluate whether such genetic defects may increase the risk of a severe course of SARS-CoV2 infection in patients with sarcoidosis. We extended a whole exome screening to 13 families predisposed to sarcoidosis and crossed the genes sharing mutations with the list of genes involved in the SARS-CoV2 host-pathogen protein-protein interactome. A similar analysis protocol was applied to a series of 100 healthy individuals. Using ENRICH.R, a comprehensive gene set enrichment web server, we identified the functional pathways represented in the set of genes carrying deleterious mutations and confirmed the overrepresentation of autophagy- and mitophagy-related functions in familial cases of sarcoidosis. The same protocol was applied to the set of genes common to sarcoidosis and the SARS-CoV2-host interactome and found a significant enrichment of genes related to mitochondrial factors involved in autophagy, mitophagy, and RIG-I-like (Retinoic Acid Inducible Gene 1) Receptor antiviral response signaling. From these results, we discuss the hypothesis according to which sarcoidosis is a model for studying genetic abnormalities associated with host response to viral infections as a consequence of defects in autophagy and mitophagy processes.

Protection against neonatal respiratory viral infection via maternal treatment during pregnancy with the benign immune training agent OM-85

Objectives

Incomplete maturation of immune regulatory functions at birth is antecedent to the heightened risk for severe respiratory infections during infancy. Our forerunner animal model studies demonstrated that maternal treatment with the microbial‐derived immune training agent OM‐85 during pregnancy promotes accelerated postnatal maturation of mechanisms that regulate inflammatory processes in the offspring airways. Here, we aimed to provide proof of concept for a novel solution to reduce the burden and potential long‐term sequelae of severe early‐life respiratory viral infection through maternal oral treatment during pregnancy with OM‐85, already in widespread human clinical use.

Methods

In this study, we performed flow cytometry and targeted gene expression (RT‐qPCR) analysis on lungs from neonatal offspring whose mothers received oral OM‐85 treatment during pregnancy. We next determined whether neonatal offspring from OM‐85 treated mothers demonstrate enhanced protection against lethal lower respiratory infection with mouse‐adapted rhinovirus (vMC₀), and associated lung immune changes.

Results

Offspring from mothers treated with OM‐85 during pregnancy display accelerated postnatal seeding of lung myeloid populations demonstrating upregulation of function‐associated markers. Offspring from OM‐85 mothers additionally exhibit enhanced expression of TLR4/7 and the IL‐1β/NLRP3 inflammasome complex within the lung. These treatment effects were associated with enhanced capacity to clear an otherwise lethal respiratory viral infection during the neonatal period, with concomitant regulation of viral‐induced IFN response intensity.

Conclusion

These results demonstrate that maternal OM‐85 treatment protects offspring against lethal neonatal respiratory viral infection by accelerating development of innate immune mechanisms crucial for maintenance of local immune homeostasis in the face of pathogen challenge.