Migratory Neural Crest Cells Phagocytose Dead Cells in the Developing Nervous System.

During neural tube closure and spinal cord development, many cells die in both the central and peripheral nervous systems (CNS and PNS, respectively). However, myeloid-derived professional phagocytes have not yet colonized the trunk region during early neurogenesis. How apoptotic cells are removed from this region during these stages remains largely unknown. Using live imaging in zebrafish, we demonstrate that neural crest cells (NCCs) respond rapidly to dying cells and phagocytose cellular debris around the neural tube. Additionally, NCCs have the ability to enter the CNS through motor exit point transition zones and clear debris in the spinal cord. Surprisingly, NCCs phagocytosis mechanistically resembles macrophage phagocytosis and their recruitment toward cellular debris is mediated by interleukin-1ß. Taken together, our results reveal a role for NCCs in phagocytosis of debris in the developing nervous system before the presence of professional phagocytes.

Modulation of Myelopoiesis Progenitors Is an Integral Component of Trained Immunity.

Trained innate immunity fosters a sustained favorable response of myeloid cells to a secondary challenge, despite their short lifespan in circulation. We thus hypothesized that trained immunity acts via modulation of hematopoietic stem and progenitor cells (HSPCs). Administration of ß-glucan (prototypical trained-immunity-inducing agonist) to mice induced expansion of progenitors of the myeloid lineage, which was associated with elevated signaling by innate immune mediators, such as IL-1ß and granulocyte-macrophage colony-stimulating factor (GM-CSF), and with adaptations in glucose metabolism and cholesterol biosynthesis. The trained-immunity-related increase in myelopoiesis resulted in a beneficial response to secondary LPS challenge and protection from chemotherapy-induced myelosuppression in mice. Therefore, modulation of myeloid progenitors in the bone marrow is an integral component of trained immunity, which to date, was considered to involve functional changes of mature myeloid cells in the periphery.

IL-1ß-associated NNT acetylation orchestrates iron-sulfur cluster maintenance and cancer immunotherapy resistance.

Interleukin-1ß (IL-1ß) is a key protein in inflammation and contributes to tumor progression. However, the role of IL-1ß in cancer is ambiguous or even contradictory. Here, we found that upon IL-1ß stimulation, nicotinamide nucleotide transhydrogenase (NNT) in cancer cells is acetylated at lysine (K) 1042 (NNT K1042ac) and thereby induces the mitochondrial translocation of p300/CBP-associated factor (PCAF). This acetylation enhances NNT activity by increasing the binding affinity of NNT for NADP+ and therefore boosts NADPH production, which subsequently sustains sufficient iron-sulfur cluster maintenance and protects tumor cells from ferroptosis. Abrogating NNT K1042ac dramatically attenuates IL-1ß-promoted tumor immune evasion and synergizes with PD-1 blockade. In addition, NNT K1042ac is associated with IL-1ß expression and the prognosis of human gastric cancer. Our findings demonstrate a mechanism of IL-1ß-promoted tumor immune evasion, implicating the therapeutic potential of disrupting the link between IL-1ß and tumor cells by inhibiting NNT acetylation.

Intestinal Permeability and IgA Provoke Immune Vasculitis Linked to Cardiovascular Inflammation.

Recent experimental data and clinical, genetic, and transcriptome evidence from patients converge to suggest a key role of interleukin-1ß (IL-1ß) in the pathogenesis of Kawasaki disease (KD). However, the molecular mechanisms involved in the development of cardiovascular lesions during KD vasculitis are still unknown. Here, we investigated intestinal barrier function in KD vasculitis and observed evidence of intestinal permeability and elevated circulating secretory immunoglobulin A (sIgA) in KD patients, as well as elevated sIgA and IgA deposition in vascular tissues in a mouse model of KD vasculitis. Targeting intestinal permeability corrected gut permeability, prevented IgA deposition and ameliorated cardiovascular pathology in the mouse model. Using genetic and pharmacologic inhibition of IL-1ß signaling, we demonstrate that IL-1ß lies upstream of disrupted intestinal barrier function, subsequent IgA vasculitis development, and cardiac inflammation. Targeting mucosal barrier dysfunction and the IL-1ß pathway may also be applicable to other IgA-related diseases, including IgA vasculitis and IgA nephropathy.

Pyroptosis in neutrophils: Multimodal integration of inflammasome and regulated cell death signaling pathways.

Pyroptosis is a proinflammatory mode of lytic cell death mediated by accumulation of plasma membrane (PM) macropores composed of gasdermin-family (GSDM) proteins. It facilitates two major functions in innate immunity: (i) elimination of intracellular replicative niches for pathogenic bacteria; and (ii) non-classical secretion of IL-1 family cytokines that amplify host-beneficial inflammatory responses to microbial infection or tissue damage. Physiological roles for gasdermin D (GSDMD) in pyroptosis and IL-1ß release during inflammasome signaling have been extensively characterized in macrophages. This involves cleavage of GSDMD by caspase-1 to generate GSDMD macropores that mediate IL-1ß efflux and progression to pyroptotic lysis. Neutrophils, which rapidly accumulate in large numbers at sites of tissue infection or damage, become the predominant local source of IL-1ß in coordination with their potent microbiocidal capacity. Similar to macrophages, neutrophils express GSDMD and utilize the same spectrum of diverse inflammasome platforms for caspase-1-mediated cleavage of GSDMD. Distinct from macrophages, neutrophils possess a remarkable capacity to resist progression to GSDMD-dependent pyroptotic lysis to preserve their viability for efficient microbial killing while maintaining GSDMD-dependent mechanisms for export of bioactive IL-1ß. Rather, neutrophils employ cell-specific mechanisms to conditionally engage GSDMD-mediated pyroptosis in response to bacterial pathogens that use neutrophils as replicative niches. GSDMD and pyroptosis have also been mechanistically linked to induction of NETosis, a signature neutrophil pathway that expels decondensed nuclear DNA into extracellular compartments for immobilization and killing of microbial pathogens. This review summarizes a rapidly growing number of recent studies that have produced new insights, unexpected mechanistic nuances, and some controversies regarding the regulation of, and roles for, neutrophil inflammasomes, pyroptosis, and GSDMs in diverse innate immune responses.

Reactive Oxygen Species Localization Programs Inflammation to Clear Microbes of Different Size.

How the number of immune cells recruited to sites of infection is determined and adjusted to differences in the cellular stoichiometry between host and pathogen is unknown. Here, we have uncovered a role for reactive oxygen species (ROS) as sensors of microbe size. By sensing the differential localization of ROS generated in response to microbes of different size, neutrophils tuned their interleukin (IL)-1ß expression via the selective oxidation of NF-κB, in order to implement distinct inflammatory programs. Small microbes triggered ROS intracellularly, suppressing IL-1ß expression to limit neutrophil recruitment as each phagocyte eliminated numerous pathogens. In contrast, large microbes triggered ROS extracellularly, amplifying IL-1ß expression to recruit numerous neutrophils forming cooperative clusters. Defects in ROS-mediated microbe size sensing resulted in large neutrophil infiltrates and clusters in response to small microbes that contribute to inflammatory disease. These findings highlight the impact of ROS localization on signal transduction.

ORMDL3 regulates NLRP3 inflammasome activation by maintaining ER-mitochondria contacts in human macrophages and dictates ulcerative colitis patient outcome.

Genome-wide association studies in inflammatory bowel disease have identified risk loci in the orosomucoid-like protein 3/ORMDL sphingolipid biosynthesis regulator 3 (ORMDL3) gene to confer susceptibility to ulcerative colitis (UC), but the underlying functional relevance remains unexplored. Here, we found that a subpopulation of the UC patients who had higher disease activity shows enhanced expression of ORMDL3 compared to the patients with lower disease activity and the non-UC controls. We also found that the patients showing high ORMDL3 mRNA expression have elevated interleukin-1ß cytokine levels indicating positive correlation. Further, knockdown of ORMDL3 in the human monocyte-derived macrophages resulted in significantly reduced interleukin-1ß release. Mechanistically, we report for the first time that ORMDL3 contributes to a mounting inflammatory response via modulating mitochondrial morphology and activation of the NLRP3 inflammasome. Specifically, we observed an increased fragmentation of mitochondria and enhanced contacts with the endoplasmic reticulum (ER) during ORMDL3 over-expression, enabling efficient NLRP3 inflammasome activation. We show that ORMDL3 that was previously known to be localized in the ER also becomes localized to mitochondria-associated membranes and mitochondria during inflammatory conditions. Additionally, ORMDL3 interacts with mitochondrial dynamic regulating protein Fis-1 present in the mitochondria-associated membrane. Accordingly, knockdown of ORMDL3 in a dextran sodium sulfate -induced colitis mouse model showed reduced colitis severity. Taken together, we have uncovered a functional role for ORMDL3 in mounting inflammation during UC pathogenesis by modulating ER-mitochondrial contact and dynamics.

Phosphorylation of USP20 on Ser334 by IRAK1 promotes IL-1ß-evoked signaling in vascular smooth muscle cells and vascular inflammation.

Reversible lysine-63 (K63) polyubiquitination regulates proinflammatory signaling in vascular smooth muscle cells (SMCs) and plays an integral role in atherosclerosis. Ubiquitin-specific peptidase 20 (USP20) reduces NFκB activation triggered by proinflammatory stimuli, and USP20 activity attenuates atherosclerosis in mice. The association of USP20 with its substrates triggers deubiquitinase activity; this association is regulated by phosphorylation of USP20 on Ser334 (mouse) or Ser333 (human). USP20 Ser333 phosphorylation was greater in SMCs of atherosclerotic segments of human arteries as compared with nonatherosclerotic segments. To determine whether USP20 Ser334 phosphorylation regulates proinflammatory signaling, we created USP20-S334A mice using CRISPR/Cas9-mediated gene editing. USP20-S334A mice developed ∼50% less neointimal hyperplasia than congenic WT mice after carotid endothelial denudation. WT carotid SMCs showed substantial phosphorylation of USP20 Ser334, and WT carotids demonstrated greater NFκB activation, VCAM-1 expression, and SMC proliferation than USP20-S334A carotids. Concordantly, USP20-S334A primary SMCs in vitro proliferated and migrated less than WT SMCs in response to IL-1ß. An active site ubiquitin probe bound to USP20-S334A and USP20-WT equivalently, but USP20-S334A associated more avidly with TRAF6 than USP20-WT. IL-1ß induced less K63-linked polyubiquitination of TRAF6 and less downstream NFκB activity in USP20-S334A than in WT SMCs. Using in vitro phosphorylation with purified IRAK1 and siRNA-mediated gene silencing of IRAK1 in SMCs, we identified IRAK1 as a novel kinase for IL-1ß-induced USP20 Ser334 phosphorylation. Our findings reveal novel mechanisms regulating IL-1ß-induced proinflammatory signaling: by phosphorylating USP20 Ser334, IRAK1 diminishes the association of USP20 with TRAF6 and thus augments NFκB activation, SMC inflammation, and neointimal hyperplasia.

Role of caspase-11 non-canonical inflammasomes in retinal ischemia/reperfusion injury.

BACKGROUND: Retinal ischemia/reperfusion (IR) injury is a common pathological process in many ophthalmic diseases. Interleukin-1ß (IL-1ß) is an important inflammatory factor involved in the pathology of retinal IR injury, but the mechanism by which IL-1ß is regulated in such injury remains unclear. Caspase-11 non-canonical inflammasomes can regulate the synthesis and secretion of IL-1ß, but its role in retinal IR injury has not been elucidated. This study aimed to evaluate the role of caspase-11 non-canonical inflammasomes in retinal IR injury. METHODS: Retinal IR injury was induced in C57BL/6J mice by increasing the intraocular pressure to 110 mmHg for 60 min. The post-injury changes in retinal morphology and function and in IL-1ß expression were compared between caspase-11 gene knockout (caspase-11-/-) mice and wild-type (WT) mice. Morphological and functional changes were evaluated using hematoxylin-eosin staining and retinal whole mount staining and using electroretinography (ERG), respectively. IL-1ß expression in the retina was measured using enzyme-linked immunosorbent assay (ELISA). The levels of caspase-11-related protein were measured using western blot analysis. The location of caspase-11 in the retina was determined via immunofluorescence staining. Mouse type I astrocytes C8-D1A cells were used to validate the effects of caspase-11 simulation via hypoxia in vitro. Small-interfering RNA targeting caspase-11 was constructed. Cell viability was evaluated using the MTT assay. IL-1ß expression in supernatant and cell lysate was measured using ELISA. The levels of caspase-11-related protein were measured using western blot analysis. RESULTS: Retinal ganglion cell death and retinal edema were more ameliorated, and the ERG b-wave amplitude was better after retinal IR injury in caspase-11-/- mice than in WT mice. Further, caspase-11-/- mice showed lower protein expressions of IL-1ß, cleaved caspase-1, and gasdermin D (GSDMD) in the retina after retinal IR injury. Caspase-11 protein was expressed in retinal glial cells, and caspase-11 knockdown played a protective role against hypoxia in C8-D1A cells. The expression levels of IL-1ß, cleaved caspase-1, and GSDMD were inhibited after hypoxia in the si-caspase-11 constructed cells. CONCLUSIONS: Retinal IR injury activates caspase-11 non-canonical inflammasomes in glial cells of the retina. This results in increased protein levels of GSDMD and IL-1ß and leads to damage in the inner layer of the retina.

Long-term efficacy of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in two patients with sJIA and recurrent episodes of MAS.

INTRODUCTION: Systemic juvenile idiopathic arthritis (sJIA), a multifaceted autoinflammatory disorder, can be complicated by life-threatening conditions such as macrophage activation syndrome (MAS) and interstitial lung disease (ILD). The management of these conditions presents a therapeutic challenge, underscoring the need for innovative treatment approaches. OBJECTIVES: to report the possible role of MAS825, a bispecific anti-IL1ß and IL-18 monoclonal antibody, in the treatment of multi-drug-resistant sJIA. METHODS: We report two patients affected by sJIA with severe and refractory MAS and high serum IL-18 levels, responding to dual blockade of IL-1ß and IL-18. RESULTS: The first patient is a 20-year-old man, presenting a severe MAS complicated by thrombotic microangiopathy, following SARS-CoV-2 infection. He was treated with MAS825, with quick improvement. Eighteen months later, the patient is still undergoing biweekly treatment with MAS825, associated with MTX, ciclosporin and low-dose glucocorticoids, maintaining good control over the systemic features of the disease.The second patient, a 10-year-old girl, presented a severe MAS case, complicated by posterior reversible encephalopathy syndrome (PRES), following an otomastoiditis. The MAS was not fully controlled despite treatment with IV high-dose glucocorticoids, anakinra and ciclosporin. She began biweekly MAS825, which led to a prompt amelioration of MAS parameters. After 10 months, the patient continues to receive MAS825 and is in complete remission. CONCLUSION: In light of the pivotal role of IL-1ß and IL-18 in sJIA, MAS and ILD, MAS825 might represent a possible valid and safe option in the treatment of drug-resistant sJIA, especially in the presence of high serum IL-18 levels.

Melatonin improves influenza virus infection-induced acute exacerbation of COPD by suppressing macrophage M1 polarization and apoptosis.

BACKGROUND: Influenza A viruses (IAV) are extremely common respiratory viruses for the acute exacerbation of chronic obstructive pulmonary disease (AECOPD), in which IAV infection may further evoke abnormal macrophage polarization, amplify cytokine storms. Melatonin exerts potential effects of anti-inflammation and anti-IAV infection, while its effects on IAV infection-induced AECOPD are poorly understood. METHODS: COPD mice models were established through cigarette smoke exposure for consecutive 24 weeks, evaluated by the detection of lung function. AECOPD mice models were established through the intratracheal atomization of influenza A/H3N2 stocks in COPD mice, and were injected intraperitoneally with melatonin (Mel). Then, The polarization of alveolar macrophages (AMs) was assayed by flow cytometry of bronchoalveolar lavage (BAL) cells. In vitro, the effects of melatonin on macrophage polarization were analyzed in IAV-infected Cigarette smoking extract (CSE)-stimulated Raw264.7 macrophages. Moreover, the roles of the melatonin receptors (MTs) in regulating macrophage polarization and apoptosis were determined using MTs antagonist luzindole. RESULTS: The present results demonstrated that IAV/H3N2 infection deteriorated lung function (reduced FEV20,50/FVC), exacerbated lung damages in COPD mice with higher dual polarization of AMs. Melatonin therapy improved airflow limitation and lung damages of AECOPD mice by decreasing IAV nucleoprotein (IAV-NP) protein levels and the M1 polarization of pulmonary macrophages. Furthermore, in CSE-stimulated Raw264.7 cells, IAV infection further promoted the dual polarization of macrophages accompanied with decreased MT1 expression. Melatonin decreased STAT1 phosphorylation, the levels of M1 markers and IAV-NP via MTs reflected by the addition of luzindole. Recombinant IL-1ß attenuated the inhibitory effects of melatonin on IAV infection and STAT1-driven M1 polarization, while its converting enzyme inhibitor VX765 potentiated the inhibitory effects of melatonin on them. Moreover, melatonin inhibited IAV infection-induced apoptosis by suppressing IL-1ß/STAT1 signaling via MTs. CONCLUSIONS: These findings suggested that melatonin inhibited IAV infection, improved lung function and lung damages of AECOPD via suppressing IL-1ß/STAT1-driven macrophage M1 polarization and apoptosis in a MTs-dependent manner. Melatonin may be considered as a potential therapeutic agent for influenza virus infection-induced AECOPD.

HIF-1α inhibition in macrophages preserves acute liver failure by reducing IL-1ß production.

The development of acute liver failure (ALF) is dependent on its local inducer. Inflammation is a high-frequency and critical factor that accelerates hepatocyte death and liver failure. In response to injury stress, the expression of the transcription factor hypoxia-inducible factor-1α (HIF-1α) in macrophages is promoted by both oxygen-dependent and oxygen-independent mechanisms, thus promoting the expression and secretion of the cytokine interleukin-1ß (IL-1ß). IL-1ß further induces hepatocyte apoptosis or necrosis by signaling through the receptor (IL-1R) on hepatocyte. HIF-1α knockout in macrophages or IL-1R knockout in hepatocytes protects against liver failure. However, whether HIF-1α inhibition in macrophages has a protective role in ALF is unclear. In this study, we revealed that the small molecule HIF-1α inhibitor PX-478 inhibits the expression and secretion of IL-1ß, but not tumor necrosis factor α (TNFα), in bone marrow-derived macrophages (BMDMs). PX-478 pretreatment alleviates liver injury in LPS/D-GalN-induced ALF mice by decreasing the hepatic inflammatory response. In addition, preventive or therapeutic administration of PX-478 combined with TNFα neutralizing antibody markedly improved LPS/D-GalN-induced ALF. Taken together, our data suggest that PX-478 administration leads to HIF-1α inhibition and decreased IL-1ß secretion in macrophages, which represents a promising therapeutic strategy for inflammation-induced ALF.

Interleukin-1ß moderates the relationships between middle frontal-mACC/insular connectivity and depressive symptoms in bipolar II depression.

The functional alterations of the brain in bipolar II depression (BDII-D) and their clinical and inflammatory associations are understudied. We aim to investigate the functional brain alterations in BDII-D and their relationships with inflammation, childhood adversity, and psychiatric symptoms, and to examine the moderating effects among these factors. Using z-normalized amplitude of low-frequency fluctuation (zALFF), we assessed the whole-brain resting-state functional activity between 147 BDII-D individuals and 150 healthy controls (HCs). Differential ALFF regions were selected as seeds for functional connectivity analysis to observe brain connectivity alterations resulting from abnormal regional activity. Four inflammatory cytokines including interleukin (IL)-6, IL-1ß, tumor necrosis factor (TNF)-α, and C-reactive protein (CRP) and five clinical scales including Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), Positive and Negative Syndrome Scale (PANSS), Columbia-Suicide Severity Rating Scale (C-SSRS), and Childhood Trauma Questionnaire (CTQ) were tested and assessed in BDII-D. Partial correlations with multiple comparison corrections identified relationships between brain function and inflammation, childhood adversity, and psychiatric symptoms. Moderation analysis was conducted based on correlation results and previous findings. Compared to HCs, BDII-D individuals displayed significantly lower zALFF in the superior and middle frontal gyri (SFG and MFG) and insula, but higher zALFF in the occipital-temporal area. Only the MFG and insula-related connectivity exhibited significant differences between groups. Within BDII-D, lower right insula zALFF value correlated with higher IL-6, CRP, and emotional adversity scores, while lower right MFG zALFF was related to higher CRP and physical abuse scores. Higher right MFG-mid-anterior cingulate cortex (mACC) connectivity was associated with higher IL-1ß. Moreover, IL-1ß moderated associations between higher right MFG-mACC/insula connectivity and greater depressive symptoms. This study reveals that abnormal functional alterations in the right MFG and right insula were associated with elevated inflammation, childhood adversity, and depressive symptoms in BDII-D. IL-1ß may moderate the relationship between MFG-related connectivity and depressive symptoms.

Adjunctive canakinumab reduces peripheral inflammation markers and improves positive symptoms in people with schizophrenia and inflammation: A randomized control trial.

BACKGROUND: Clinical trials of anti-inflammatories in schizophrenia do not show clear and replicable benefits, possibly because patients were not recruited based on elevated inflammation status. Interleukin 1-beta (IL-1ß) mRNA and protein levels are increased in serum, plasma, cerebrospinal fluid, and brain of some chronically ill patients with schizophrenia, first episode psychosis, and clinical high-risk individuals. Canakinumab, an approved anti-IL-1ß monoclonal antibody, interferes with the bioactivity of IL-1ß and interrupts downstream signaling. However, the extent to which canakinumab reduces peripheral inflammation markers, such as, high sensitivity C-reactive protein (hsCRP) and symptom severity in schizophrenia patients with inflammation is unknown. TRIAL DESIGN: We conducted a randomized, placebo-controlled, double-blind, parallel groups, 8-week trial of canakinumab in chronically ill patients with schizophrenia who had elevated peripheral inflammation. METHODS: Twenty-seven patients with schizophrenia or schizoaffective disorder and elevated peripheral inflammation markers (IL-1ß, IL-6, hsCRP and/or neutrophil to lymphocyte ratio: NLR) were randomized to a one-time, subcutaneous injection of canakinumab (150 mg) or placebo (normal saline) as an adjunctive antipsychotic treatment. Peripheral blood hsCRP, NLR, IL-1ß, IL-6, IL-8 levels were measured at baseline (pre injection) and at 1-, 4- and 8-weeks post injection. Symptom severity was assessed at baseline and 4- and 8-weeks post injection. RESULTS: Canakinumab significantly reduced peripheral hsCRP over time, F(3, 75) = 5.16, p = 0.003. Significant hsCRP reductions relative to baseline were detected only in the canakinumab group at weeks 1, 4 and 8 (p's = 0.0003, 0.000002, and 0.004, respectively). There were no significant hsCRP changes in the placebo group. Positive symptom severity scores were significantly reduced at week 8 (p = 0.02) in the canakinumab group and week 4 (p = 0.02) in the placebo group. The change in CRP between week 8 and baseline (b = 1.9, p = 0.0002) and between week 4 and baseline (b = 6.0, p = 0.001) were highly significant predictors of week 8 change in PANSS Positive Symptom severity scores. There were no significant changes in negative symptoms, general psychopathology or cognition in either group. Canakinumab was well tolerated and only 7 % discontinued. CONCLUSIONS: Canakinumab quickly reduces peripheral hsCRP serum levels in patients with schizophrenia and inflammation; after 8 weeks of canakinumab treatment, the reductions in hsCRP are related to reduced positive symptom severity. Future studies should consider increased doses or longer-term treatment to confirm the potential benefits of adjunctive canakinumab in schizophrenia. Australian and New Zealand Clinical Trials Registry number: ACTRN12615000635561.

IL-1ß-activated PI3K/AKT and MEK/ERK pathways coordinately promote induction of partial epithelial-mesenchymal transition.

Epithelial-mesenchymal transition (EMT) is a cellular process in embryonic development, wound healing, organ fibrosis, and cancer metastasis. Previously, we and others have reported that proinflammatory cytokine interleukin-1ß (IL-1ß) induces EMT. However, the exact mechanisms, especially the signal transduction pathways, underlying IL-1ß-mediated EMT are not yet completely understood. Here, we found that IL-1ß stimulation leads to the partial EMT-like phenotype in human lung epithelial A549 cells, including the gain of mesenchymal marker (vimentin) and high migratory potential, without the complete loss of epithelial marker (E-cadherin). IL-1ß-mediated partial EMT induction was repressed by PI3K inhibitor LY294002, indicating that the PI3K/AKT pathway plays a significant role in the induction. In addition, ERK1/2 inhibitor FR180204 markedly inhibited the IL-1ß-mediated partial EMT induction, demonstrating that the MEK/ERK pathway was also involved in the induction. Furthermore, we found that the activation of the PI3K/AKT and MEK/ERK pathways occurred downstream of the epidermal growth factor receptor (EGFR) pathway and the IL-1 receptor (IL-1R) pathway, respectively. Our findings suggest that the PI3K/AKT and MEK/ERK pathways coordinately promote the IL-1ß-mediated partial EMT induction. The inhibition of not one but both pathways is expected yield clinical benefits by preventing partial EMT-related disorders such as organ fibrosis and cancer metastasis.

Modulation of apoptosis and Inflammasome activation in chondrocytes: co-regulatory role of Chlorogenic acid.

BACKGROUND: The B-cell lymphoma 2 (Bcl-2) protein regulates programmed cell death throughout the disease conditions by upholding apoptotic pathways. However, the mechanism by which it's expressed in chondrocytes still needs to be studied in chondrocyte-related disorders. Additionally, exploring the potential therapeutic role of Chlorogenic acid (CGA) in confluence with Bcl-2 modulation is of significant interest. METHODS: In vivo and in vitro studies were performed according to our previous methodologies. The chondrocytes were cultured in specific growth media under standard conditions after expression verification of different microRNAs through high-throughput sequencing and verification of Bcl-2 involvement in tibial growth plates. The effect of Bcl-2 expression was investigated by transfecting chondrocytes with miR-460a, siRNA, and their negative controls alone or in combination with CGA. The RNA was extracted and subjected to a reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Western blot analysis and immunofluorescence assays were performed to visualize the intracellular localization of Bcl-2 and associated proteins related to apoptotic and inflammasome pathways. Moreover, apoptosis through flow cytometry was also performed to understand the modulation of concerning pathways. RESULTS: The suppression of Bcl-2 induced higher apoptosis and mitochondrial dysfunction, leading to IL-1ß maturation and affecting the inflammasome during chondrocyte proliferation. Conversely, overexpression attenuated the activation, as evidenced by reduced caspase activity and IL-1ß maturation. In parallel, CGA successfully reduced siRNA-induced apoptosis by decreasing Cytochrome C (Cyto C) release from the mitochondria to the cytoplasm, which in turn decreased Caspase-3 and Caspase-7 cleavage with Bcl-2-associated X protein (Bax). Furthermore, siBcl-2 transfection and CGA therapy increased chondrocyte proliferation and survival. The CGA also showed a promising approach to maintaining chondrocyte viability by inhibiting siRNA-induced apoptosis. CONCLUSIONS: Targeting Bcl-2-mediated regulation might be a possible treatment for chondrocyte-related conditions. Moreover, these results add knowledge of the complicated processes underlying chondrocyte function and the pathophysiology of related diseases, highlighting the significance of target specific therapies. Video Abstract.

Contrasting Iron Metabolism in Undifferentiated Versus Differentiated MO3.13 Oligodendrocytes via IL-1ß-Induced Iron Regulatory Protein 1.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by the loss of dopaminergic neurons and the accumulation of iron in the substantia nigra. While iron accumulation and inflammation are implicated in PD pathogenesis, their impact on oligodendrocytes, the brain's myelin-forming cells, remains elusive. This study investigated the influence of interleukin-1ß (IL-1ß), an elevated proinflammatory cytokine in PD, on iron-related proteins in MO3.13 oligodendrocytes. We found that IL-1ß treatment in undifferentiated MO3.13 oligodendrocytes increased iron regulatory protein 1 and transferrin receptor 1 (TfR1) expression while decreasing ferroportin 1 (FPN1) expression. Consequently, iron uptake was enhanced, and iron release was reduced, leading to intracellular iron accumulation. Conversely, IL-1ß treatment in differentiated MO3.13 oligodendrocytes exhibited the opposite effect, with decreased TfR1 expression, increased FPN1 expression, and reduced iron uptake. These findings suggest that IL-1ß-induced dysregulation of iron metabolism in oligodendrocytes may contribute to the pathological processes observed in PD. IL-1ß can increase the iron content in undifferentiated oligodendrocytes, thus facilitating the differentiation of undifferentiated MO3.13 oligodendrocytes. In differentiated oligodendrocytes, IL-1ß may facilitate iron release, providing a potential source of iron for neighboring dopaminergic neurons, thereby initiating a cascade of deleterious events. This study provides valuable insights into the intricate interplay between inflammation, abnormal iron accumulation, and oligodendrocyte dysfunction in PD. Targeting the IL-1ß-mediated alterations in iron metabolism may hold therapeutic potential for mitigating neurodegeneration and preserving dopaminergic function in PD.

Nlrp3 inflammasome activation in macrophages suffices for inducing autoinflammation in mice.

Cryopyrin-associated periodic syndromes (CAPS) are a spectrum of autoinflammatory disorders caused by gain-of-function NLRP3 mutant proteins that form hyperactive inflammasomes leading to overproduction of the pro-inflammatory cytokines IL-1ß and IL-18. Expressing the murine gain-of-function Nlrp3A350V mutant selectively in neutrophils recapitulates several autoinflammatory features of human CAPS, but the potential contribution of macrophage inflammasome hyperactivation to CAPS development is poorly defined. Here, we show that expressing Nlrp3A350V in macrophages is sufficient for driving severe multi-organ autoinflammation leading to perinatal lethality in mice. In addition, we show that macrophages contribute to autoinflammation also in adult mice, as depleting macrophages in mice ubiquitously expressing Nlrp3A350V significantly diminishes splenic and hepatic IL-1ß production. Interestingly, inflammation induced by macrophage-selective Nlrp3A350V expression does not provoke an influx of mature neutrophils, while neutrophil influx is still occurring in macrophage-depleted mice with body-wide Nlrp3A350V expression. These observations identify macrophages as important cellular drivers of CAPS in mice and support a cooperative cellular model of CAPS development in which macrophages and neutrophils act independently of each other in propagating severe autoinflammation.

Autophagy reduces aortic calcification in diabetic mice by reducing matrix vesicle body-mediated IL-1ß release.

Vascular calcification (VC) is a common pathological process of cardiovascular disease that occurs in patients with type 2 diabetes mellitus (T2DM). However, the molecular basis of VC progression remains unknown. A GEO dataset (GSE146638) was analyzed to show that microbodies and IL-1ß may play important roles in the pathophysiology of VC. The release of matrix vesicle bodies (MVBs) and IL-1ß and the colocalization of IL-1ß with MVBs or autophagosomes were studied by immunofluorescence in an in vivo diabetes mouse model with aortic calcification and an in vitro high glucose cell calcification model. MVB numbers, IL-1ß levels and autophagy were increased in calcified mouse aortas and calcified vascular smooth muscle cells (VSMCs). IL-1ß colocalized with MVBs and autophagosomes. The MVBs from calcified VSMCs induced the calcification of normal recipient VSMCs, and this effect was alleviated by silencing IL-1ß. The autophagy inducer rapamycin reduced IL-1ß expression and calcification in VSMCs, while these processes were induced by the autophagy inhibitor chloroquine. In conclusion, our results suggested that MVBs could carry IL-1ß out of cells and induce VC in normal VSMCs, and these processes could be counteracted by autophagy. These results suggested that MVB-mediated IL-1ß release may be an effective target for treating vascular calcification.

Vitamin B6 alleviates osteoarthritis by suppressing inflammation and apoptosis.

BACKGROUND: Although various anti-inflammatory medicines are widely recommended for osteoarthritis (OA) treatment, no significantly clinical effect has been observed. This study aims to examine the effects of vitamin B6, a component that has been reported to be capable of alleviating inflammation and cell death in various diseases, on cartilage degeneration in OA. METHODS: Collagen-induced arthritis (CIA) mice model were established and the severity of OA in cartilage was determined using the Osteoarthritis Research Society International (OARSI) scoring system. The mRNA and protein levels of indicators associated with extracellular matrix (ECM) metabolism, apoptosis and inflammation were detected. The effect of vitamin B6 (VB6) on the mice were assessed using HE staining and masson staining. The apoptosis rate of cells was assessed using TdT-mediated dUTP nick end labeling. RESULTS: Our results showed a trend of improved OARSI score in mice treated with VB6, which remarkably inhibited the hyaline cartilage thickness, chondrocyte disordering, and knees hypertrophy. Moreover, the VB6 supplementation reduced the protein expression of pro-apoptosis indicators, including Bax and cleaved caspase-3 and raised the expression level of anti-apoptosis marker Bcl-2. Importantly, VB6 improved ECM metabolism in both in vivo and in vitro experiments. CONCLUSIONS: This study demonstrated that VB6 alleviates OA through regulating ECM metabolism, inflammation and apoptosis in chondrocytes and CIA mice. The findings in this study provide a theoretical basis for targeted therapy of OA, and further lay the theoretical foundation for studies of mechanisms of VB6 in treating OA.