STAT3 serine phosphorylation is required for TLR4 metabolic reprogramming and IL-1β expression

Reprogramming macrophage metabolism following myocardial infarction: A neglected piece of a therapeutic opportunity

Given the global prevalence of myocardial infarction (MI) as the leading cause of mortality, there is an urgent need to devise novel strategies that target reducing infarct size, accelerating cardiac tissue repair, and preventing detrimental left ventricular (LV) remodeling. Macrophages, as a predominant type of innate immune cells, undergo metabolic reprogramming following MI, resulting in alterations in function and phenotype that significantly impact the progression of MI size and LV remodeling. This article aimed to delineate the characteristics of macrophage metabolites during reprogramming in MI and elucidate their targets and functions in cardioprotection. Furthermore, we summarize the currently proposed regulatory mechanisms of macrophage metabolic reprogramming and identify the regulators derived from endogenous products and natural small molecules. Finally, we discussed the challenges of macrophage metabolic reprogramming in the treatment of MI, with the goal of inspiring further fundamental and clinical research into reprogramming macrophage metabolism and validating its potential therapeutic targets for MI.

Mycoplasma genitalium membrane lipoprotein induces GAPDH malonylation in urethral epithelial cells to regulate cytokine response

Membrane lipoproteins serve as primary pro-inflammatory virulence factors in Mycoplasma genitalium. Membrane lipoproteins primarily induce inflammatory responses by activating Toll-like Receptor 2 (TLR2); however, the role of the metabolic status of urethral epithelial cells in inflammatory response remains unclear. In this study, we found that treatment of uroepithelial cell lines with M. genitalium membrane lipoprotein induced metabolic reprogramming, characterized by increased aerobic glycolysis, decreased oxidative phosphorylation, and increased production of the metabolic intermediates acetyl-CoA and malonyl-CoA. The metabolic shift induced by membrane lipoproteins is reversible upon blocking MyD88 and TRAM. Malonyl-CoA induces malonylation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and malonylated GAPDH could dissociate from the 3' untranslated region of TNF-α and IFN-γ mRNA. This dissociation greatly reduces the inhibitory effect on the translation of TNF-α and IFN-γ mRNA, thus achieving fine-tuning control over cytokine secretion. These findings suggest that GAPDH malonylation following M. genitalium infection is an important inflammatory signal that plays a crucial role in urogenital inflammatory diseases.

STAT3 promotes NLRP3 inflammasome activation by mediating NLRP3 mitochondrial translocation

Recognition of the translocation of NLRP3 to various organelles has provided new insights for understanding how the NLRP3 inflammasome is activated by different stimuli. Mitochondria have already been demonstrated to be the site of NLRP3 inflammasome activation, and the latest research suggests that NLRP3 is first recruited to mitochondria, then disassociated, and subsequently recruited to the Golgi network. Although some mitochondrial factors have been found to contribute to the recruitment of NLRP3 to mitochondria, the detailed process of NLRP3 mitochondrial translocation remains unclear. Here, we identify a previously unknown role for Signal transducer and activator of transcription-3 (STAT3) in facilitating the translocation of NLRP3 to mitochondria. STAT3 interacts with NLRP3 and undergoes phosphorylation at Ser727 in response to several NLRP3 agonists, enabling the translocation of STAT3 and thus the bound NLRP3 to mitochondria. Disruption of the interaction between STAT3 and NLRP3 impairs the mitochondrial localization of NLRP3, specifically suppressing NLRP3 inflammasome activation both in vitro and in vivo. In summary, we demonstrate that STAT3 acts as a transporter for mitochondrial translocation of NLRP3 and provide new insight into the spatial regulation of NLRP3.

TLR4/TNFR1 blockade suppresses STAT1/STAT3 expression and increases SOCS3 expression in modulation of LPS-induced macrophage responses

Due to the urgent need to create appropriate treatment techniques, which are currently unavailable, LPS-induced sepsis has become a serious concern on a global scale. The primary active component in the pathophysiology of inflammatory diseases such as sepsis is the Gram-negative bacterial lipopolysaccharide (LPS). LPS interacts with cell surface TLR4 in macrophages, causing the formation of reactive oxygen species (ROS), TNF-α, IL-1β and oxidative stress. It also significantly activates the MAPKs and NF-κB pathway. Excessive production of pro-inflammatory cytokines is one of the primary characteristic features in the onset and progression of inflammation. Cytokines mainly signal through the JAK/STAT pathway. We hypothesize that blocking of TLR4 along with TNFR1 might be beneficial in suppressing the effects of STAT1/STAT3 due to the stimulation of SOCS3 proteins. Prior to the LPS challenge, the macrophages were treated with antibodies against TLR4 and TNFR1 either individually or in combination. On analysis of the macrophage populations by flowcytometry, it was seen that receptor blockade facilitated the phenotypic shift of the M1 macrophages towards M2 resulting in lowered oxidative stress. Blocking of TLR4/TNFR1 upregulated the SOCS3 and mTOR expressions that enabled the transition of inflammatory M1 macrophages towards the anti-inflammatory M2 phenotype, which might be crucial in curbing the inflammatory responses. Also the reduction in the production of inflammatory cytokines such as IL-6, IL-1β due to the reduction in the activation of the STAT1 and STAT3 molecules was observed in our combination treatment group. All these results indicated that neutralization of both TLR4 and TNFR1 might provide new insights in establishing an alternative therapeutic strategy for LPS-sepsis.

Mechanism of cigarette smoke in promoting small airway remodeling in mice via STAT 3 / PINK 1-Parkin / EMT

BACKGROUND

Airway remodeling is an important pathological of airflow limitation in chronic obstructive pulmonary disease (COPD).However,its mechanism still needs to be further clarify.

METHODS

Animals:Healthy male C57BL/6 mice aged 4-6 weeks were randomly divided into control group and cigarette smoke(CS)group. Mice in the CS group were placed in a homemade glass fumigator, 5 cigarettes/time, 40 min/time, 4 times/day, 5 days/week, for 24 weeks. Mice in the control group were placed in a normal air environment.Cells:BEAS-2B cells were stimulated with 0.1%cigarette smoke extract(CSE).HE staining, immunohistochemical staining and Masson staining were used to observe the pathological of lung tissues, transmission electron microscopy was used to observe the structural of mitochondria in bronchial epithelial cells.Western blotting was used to detect the expression of STAT3,transforming growth factor-β1(TGF-β1),microtubule-associated protein 1A/1B-light chain3(LC3),PINK1,Parkin,E-cadherin,zonula occludens1(ZO-1),vimentin and snail family transcriptional inhibitor1 (Snail1),and MitoSOX Red was used to detect mitochondrial reactive oxygen species(mtROS).

RESULTS

CS exposure causes lung parenchymal destruction and airway remodeling in mice.Compared to the control group,the expression of p-STAT3,TGF-β1 and EMT in the whole lung homogenate of the CS group was increased.Mitochondrial architecture disruption in bronchial epithelial cells of CS mice, with impaired PINK1-Parkin-dependent mitophagy.In vitro experiments showed that CSE exposure led to STAT3 activation, increased TGF-β1,EMT and enhanced PINK1-Parkin-mediated mitophagy.STAT3 inhibition reversed TGF-β1 upregulation induced by CSE and improved CSE-induced EMT and mitophagy.Inhibition of mitophagy improves EMT induced by CSE. Inhibition of mitophagy reduces STAT3-induced EMT.

CONCLUSION

CS activates the STAT3,and activated STAT3 promotes EMT in bronchial epithelial cells by enhancing PINK1-Parkin-mediated mitophagy and TGF-β1 signaling.Moreover, activated STAT3 can promote EMT directly.This may be one of the mechanisms by which CS causes small airway remodeling in COPD.

Crosstalk and Prospects of TBK1 in Inflammation

BACKGROUND

TANK-binding kinase 1 (TBK1) is a pivotal mediator of innate immunity, activated by receptors such as mitochondrial antiviral signaling protein (MAVS), stimulator of interferon genes (STING), and TIR-domain-containing adaptor inducing interferon-β (TRIF). It modulates immune responses by exerting influence on the type I interferons (IFN-Is) signaling and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, Over the past few years, TBK1 multifaceted role in both immune and inflammatory responses is increasingly recognized.

METHODS AND RESULTS

This review aims to scrutinize how TBK1 operates within the NF-κB pathway and the interferon regulatory transcription factor 3 (IRF3)-dependent IFN-I pathways, highlighting the kinases and other molecules involved in these processes. This analysis reveals the distinctive characteristics of TBK1's involvement in these pathways. Furthermore, it has been observed that the role of TBK1 in exerting anti-inflammatory or pro-inflammatory effects is contingent upon varying pathological conditions, indicating a multifaceted role in immune regulation.

DISCUSSION

TBK1's evolving role in various diseases and the potential of TBK1 inhibitors as therapeutic agents are explored. Targeting TBK1 may provide new strategies for treating inflammatory disorders and autoimmune diseases associated with IFN-Is, warranting further investigation.

A hepatocyte-specific transcriptional program driven by Rela and Stat3 exacerbates experimental colitis in mice by modulating bile synthesis

Hepatic factors secreted by the liver promote homeostasis and are pivotal for maintaining the liver-gut axis. Bile acid metabolism is one such example wherein, bile acid synthesis occurs in the liver and its biotransformation happens in the intestine. Dysfunctional interactions between the liver and the intestine stimulate varied pathological outcomes through its bidirectional portal communication. Indeed, aberrant bile acid metabolism has been reported in inflammatory bowel disease (IBD). However, the molecular mechanisms underlying these crosstalks that perpetuate intestinal permeability and inflammation remain obscure. Here, we identify a novel hepatic gene program regulated by Rela and Stat3 that accentuates the inflammation in an acute experimental colitis model. Hepatocyte-specific ablation of Rela and Stat3 reduces the levels of primary bile acids in both the liver and the gut and shows a restricted colitogenic phenotype. On supplementation of chenodeoxycholic acid (CDCA), knock-out mice exhibit enhanced colitis-induced alterations. This study provides persuasive evidence for the development of multi-organ strategies for treating IBD and identifies a hepatocyte-specific Rela-Stat3 network as a promising therapeutic target.

KLF4 Induces Colorectal Cancer by Promoting EMT via STAT3 Activation

OBJECTIVE

Krüppel-like factor 4 (KLF4) has been demonstrated to exert a pro-carcinogenic effect in solid tissues. However, the precise biological function and underlying mechanisms in colorectal cancer (CRC) remains elucidated.

AIMS

To investigate whether KLF4 participates in the proliferation and invasion of CRC.

METHODS

The expression of KLF4 was investigated using immunohistochemistry and immunoblotting. The clinical significance of KLF4 was evaluated. Furthermore, the effect of inhibiting or overexpressing KLF4 on tumor was examined. Immunoblotting and qPCR were used to detect Epithelial-mesenchymal transition-related proteins levels. Additionally, the molecular function of KLF4 is related to the STAT3 signaling pathway and was determined through JASPAR, GSEA analysis, and in vitro experiments.

RESULTS

KLF4 exhibits down-regulated expression in CRC and is part of the vessel invasion, TNM stage, and worse prognosis. In vitro studies have shown that KLF4 promotes cellular proliferation and invasion, as well as EMT processes. Xenograft tumor models confirmed the oncogenic role of KLF4 in nude mice. Furthermore, GSEA and JASPAR databases analysis reveal that the binding of KLF4 to the signal transducer and activator of transcription 3 (STAT3) promoter site induces activation of p-STAT3 signaling. Subsequent targeting of STAT3 confirmed its pivotal role in mediating the oncogenic effects exerted by KLF4.

CONCLUSION

The study suggests that KLF4 activates STAT3 signaling, inducing epithelial-mesenchymal transition, thereby promoting CRC progression.

Stimuli-Mediated Macrophage Switching, Unraveling the Dynamics at the Nanoplatforms-Macrophage Interface

Macrophages play an essential role in immunotherapy and tissue regeneration owing to their remarkable plasticity and diverse functions. Recent bioengineering developments have focused on using external physical stimuli such as electric and magnetic fields, temperature, and compressive stress, among others, on micro/nanostructures to induce macrophage polarization, thereby increasing their therapeutic potential. However, it is difficult to find a concise review of the interaction between physical stimuli, advanced micro/nanostructures, and macrophage polarization. This review examines the present research on physical stimuli-induced macrophage polarization on micro/nanoplatforms, emphasizing the synergistic role of fabricated structure and stimulation for advanced immunotherapy and tissue regeneration. A concise overview of the research advancements investigating the impact of physical stimuli, including electric fields, magnetic fields, compressive forces, fluid shear stress, photothermal stimuli, and multiple stimulations on the polarization of macrophages within complex engineered structures, is provided. The prospective implications of these strategies in regenerative medicine and immunotherapeutic approaches are highlighted. This review will aid in creating stimuli-responsive platforms for immunomodulation and tissue regeneration.

Phosphorylation of PFKL regulates metabolic reprogramming in macrophages following pattern recognition receptor activation

Innate immune responses are linked to key metabolic pathways, yet the proximal signaling events that connect these systems remain poorly understood. Here we show that phosphofructokinase 1, liver type (PFKL), a rate-limiting enzyme of glycolysis, is phosphorylated at Ser775 in macrophages following several innate stimuli. This phosphorylation increases the catalytic activity of PFKL, as shown by biochemical assays and glycolysis monitoring in cells expressing phosphorylation-defective PFKL variants. Using a genetic mouse model in which PFKL Ser775 phosphorylation cannot take place, we observe that upon activation, glycolysis in macrophages is lower than in the same cell population of wild-type animals. Consistent with their higher glycolytic activity, wild-type cells have higher levels of HIF1α and IL-1β than PfklS775A/S775A after LPS treatment. In an in vivo inflammation model, PfklS775A/S775A mice show reduced levels of MCP-1 and IL-1β. Our study thus identifies a molecular link between innate immune activation and early induction of glycolysis.

miR-146a-/- mice model reveals that NF-κB inhibition reverts inflammation-driven myelofibrosis-like phenotype

Emerging evidence shows the crucial role of inflammation (particularly NF-κB pathway) in the development and progression of myelofibrosis (MF), becoming a promising therapeutic target. Furthermore, tailoring treatment with currently available JAK inhibitors (such as ruxolitinib or fedratinib) does not modify the natural history of the disease and has important limitations, including cytopenias. Since recent studies have highlighted the role of miR-146a, a negative regulator of the NF-κB pathway, in the pathogenesis of MF; here we used miR-146a-/- (KO) mice, a MF-like model lacking driver mutations, to investigate whether pharmacological inhibition of JAK/STAT and/or NF-κB pathways may reverse the myelofibrotic phenotype of these mice. Specifically, we tested the JAK1/2 inhibitor, ruxolitinib; the NF-κB inhibitor via IKKα/β, BMS-345541; both inhibitors in combination; or a dual inhibitor of both pathways (JAK2/IRAK1), pacritinib. Although all treatments decreased spleen size and partially recovered its architecture, only NF-κB inhibition, either using BMS-345541 (alone or in combination) or pacritinib, resulted in a reduction of extramedullary hematopoiesis, bone marrow (BM) fibrosis and osteosclerosis, along with an attenuation of the exacerbated inflammatory state (via IL-1β and TNFα). However, although dual inhibitor improved anemia and reversed thrombocytopenia, the combined therapy worsened anemia by inducing BM hypoplasia. Both therapeutic options reduced NF-κB and JAK/STAT signaling in a context of JAK2V617F-driven clonal hematopoiesis. Additionally, combined treatment reduced both COL1A1 and IL-6 production in an in vitro model mimicking JAK2-driven fibrosis. In conclusion, NF-κB inhibition reduces, in vitro and in vivo, disease burden and BM fibrosis, which could provide benefits in myelofibrosis patients.

The "root" causes behind the anti-inflammatory actions of ginger compounds in immune cells

Ginger (Zingiber officinale) is one of the most well-known spices and medicinal plants worldwide that has been used since ancient times to treat a plethora of diseases including cold, gastrointestinal complaints, nausea, and migraine. Beyond that, a growing body of literature demonstrates that ginger exhibits anti-inflammatory, antioxidant, anti-cancer and neuroprotective actions as well. The beneficial effects of ginger can be attributed to the biologically active compounds of its rhizome such as gingerols, shogaols, zingerone and paradols. Among these compounds, gingerols are the most abundant in fresh roots, and shogaols are the major phenolic compounds of dried ginger. Over the last two decades numerous in vitro and in vivo studies demonstrated that the major ginger phenolics are able to influence the function of various immune cells including macrophages, neutrophils, dendritic cells and T cells. Although the mechanism of action of these compounds is not fully elucidated yet, some studies provide a mechanistic insight into their anti-inflammatory effects by showing that ginger constituents are able to target multiple signaling pathways. In the first part of this review, we summarized the current literature about the immunomodulatory actions of the major ginger compounds, and in the second part, we focused on the possible molecular mechanisms that may underlie their anti-inflammatory effects.

Dysregulated STAT3 signaling and T cell immunometabolic dysfunction define a targetable, high mortality subphenotype of critically ill children

Sepsis is the leading cause of death of hospitalized children worldwide. Despite the established link between immune dysregulation and mortality in pediatric sepsis, it remains unclear which host immune factors contribute causally to adverse sepsis outcomes. Identifying modifiable pathobiology is an essential first step to successful translation of biologic insights into precision therapeutics. We designed a prospective, longitudinal cohort study of 88 critically ill pediatric patients with multiple organ dysfunction syndrome (MODS), including patients with and without sepsis, to define subphenotypes associated with targetable mechanisms of immune dysregulation. We first assessed plasma proteomic profiles and identified shared features of immune dysregulation in MODS patients with and without sepsis. We then employed consensus clustering to define three subphenotypes based on protein expression at disease onset and identified a strong association between subphenotype and clinical outcome. We next identified differences in immune cell frequency and activation state by MODS subphenotype and determined the association between hyperinflammatory pathway activation and cellular immunophenotype. Using single cell transcriptomics, we demonstrated STAT3 hyperactivation in lymphocytes from the sickest MODS subgroup and then identified an association between STAT3 hyperactivation and T cell immunometabolic dysregulation. Finally, we compared proteomics findings between patients with MODS and patients with inborn errors of immunity that amplify cytokine signaling pathways to further assess the impact of STAT3 hyperactivation in the most severe patients with MODS. Overall, these results identify a potentially pathologic and targetable role for STAT3 hyperactivation in a subset of pediatric patients with MODS who have high severity of illness and poor prognosis.

TLR4 deficiency does not alter glaucomatous progression in a mouse model of chronic glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Toll-like receptor 4 (TLR4) is a pattern-recognition transmembrane receptor that induces neuroinflammatory processes in response to injury. Tlr4 is highly expressed in ocular tissues and is known to modulate inflammatory processes in both anterior and posterior segment tissues. TLR4 activation can lead to mitochondrial dysfunction and metabolic deficits in inflammatory disorders. Due to its effects on inflammation and metabolism, TLR4 is a candidate to participate in glaucoma pathogenesis. It has been suggested as a therapeutic target based on studies using acute models, such as experimentally raising IOP to ischemia-inducing levels. Nevertheless, its role in chronic glaucoma needs further evaluation. In the current study, we investigated the role of TLR4 in an inherited mouse model of chronic glaucoma, DBA/2J. To do this, we analyzed the effect of Tlr4 knockout (Tlr4 -/-) on glaucoma-associated phenotypes in DBA/2J mice. Our studies found no significant differences in intraocular pressure, iris disease, or glaucomatous progression in Tlr4 -/- compared to Tlr4 +/+ DBA/2J mice. These data do not identify a role for TLR4 in this chronic glaucoma, but further research is warranted to understand its role in other glaucoma models and different genetic contexts.

Transcriptional profiling links unique human macrophage phenotypes to the growth of intracellular Salmonella enterica serovar Typhi

Macrophages provide a crucial environment for Salmonella enterica serovar Typhi (S. Typhi) to multiply during typhoid fever, yet our understanding of how human macrophages and S. Typhi interact remains limited. In this study, we delve into the dynamics of S. Typhi replication within human macrophages and the resulting heterogeneous transcriptomic responses of macrophages during infection. Our study reveals key factors that influence macrophage diversity, uncovering distinct immune and metabolic pathways associated with different stages of S. Typhi intracellular replication in macrophages. Of note, we found that macrophages harboring replicating S. Typhi are skewed towards an M1 pro-inflammatory state, whereas macrophages containing non-replicating S. Typhi exhibit neither a distinct M1 pro-inflammatory nor M2 anti-inflammatory state. Additionally, macrophages with replicating S. Typhi were characterized by the increased expression of genes associated with STAT3 phosphorylation and the activation of the STAT3 transcription factor. Our results shed light on transcriptomic pathways involved in the susceptibility of human macrophages to intracellular S. Typhi replication, thereby providing crucial insight into host phenotypes that restrict and support S. Typhi infection.

Pattern-Recognition Receptors and Immunometabolic Reprogramming: What We Know and What to Explore

BACKGROUND

Evolutionarily, immune response is a complex mechanism that protects the host from internal and external threats. Pattern-recognition receptors (PRRs) recognize MAMPs, PAMPs, and DAMPs to initiate a protective pro-inflammatory immune response. PRRs are expressed on the cell membranes by TLR1, 2, 4, and 6 and in the cytosolic organelles by TLR3, 7, 8, and 9, NLRs, ALRs, and cGLRs. We know their downstream signaling pathways controlling immunoregulatory and pro-inflammatory immune response. However, the impact of PRRs on metabolic control of immune cells to control their pro- and anti-inflammatory activity has not been discussed extensively.

SUMMARY

Immune cell metabolism or immunometabolism critically determines immune cells' pro-inflammatory phenotype and function. The current article discusses immunometabolic reprogramming (IR) upon activation of different PRRs, such as TLRs, NLRs, cGLRs, and RLRs. The duration and type of PRR activated, species studied, and location of immune cells to specific organ are critical factors to determine the IR-induced immune response.

KEY MESSAGE

The work herein describes IR upon TLR, NLR, cGLR, and RLR activation. Understanding IR upon activating different PRRs is critical for designing better immune cell-specific immunotherapeutics and immunomodulators targeting inflammation and inflammatory diseases.

Harnessing innate immune pathways for therapeutic advancement in cancer

The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.

Enhanced STAT3/PIK3R1/mTOR signaling triggers tubular cell inflammation and apoptosis in septic-induced acute kidney injury: implications for therapeutic intervention

Septic acute kidney injury (AKI) is a severe form of renal dysfunction associated with high morbidity and mortality rates. However, the pathophysiological mechanisms underlying septic AKI remain incompletely understood. Herein, we investigated the signaling pathways involved in septic AKI using the mouse models of lipopolysaccharide (LPS) treatment and cecal ligation and puncture (CLP). In these models, renal inflammation and tubular cell apoptosis were accompanied by the aberrant activation of the mechanistic target of rapamycin (mTOR) and the signal transducer and activator of transcription 3 (STAT3) signaling pathways. Pharmacological inhibition of either mTOR or STAT3 significantly improved renal function and reduced apoptosis and inflammation. Interestingly, inhibition of STAT3 with pharmacological inhibitors or small interfering RNA blocked LPS-induced mTOR activation in renal tubular cells, indicating a role of STAT3 in mTOR activation. Moreover, knockdown of STAT3 reduced the expression of the phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1/p85α), a key subunit of the phosphatidylinositol 3-kinase for AKT and mTOR activation. Chromatin immunoprecipitation assay also proved the binding of STAT3 to PIK3R1 gene promoter in LPS-treated kidney tubular cells. In addition, knockdown of PIK3R1 suppressed mTOR activation during LPS treatment. These findings highlight the dysregulation of mTOR and STAT3 pathways as critical mechanisms underlying the inflammatory and apoptotic phenotypes observed in renal tubular cells during septic AKI, suggesting the STAT3/ PIK3R1/mTOR pathway as a therapeutic target of septic AKI.

E. Coli LPS-induced calcium signaling regulates the expression of hypoxia-inducible factor 1α in periodontal ligament fibroblasts in a non-hypoxia-dependent manner

Periodontitis, an inflammatory disease, can cause significant damage to the oral tissues which support the teeth. During the early development of periodontitis, periodontal ligament fibroblasts (PDLFs) undergo metabolic reprogramming regulated by hypoxia-inducible factor 1α (HIF-1α), which is strongly linked to the progression of inflammation. However, the precise mechanisms by which PDLFs regulate HIF-1α and its associated metabolic reprogramming during early inflammation remain unclear. This study illustrated that brief and low-dose exposure to Escherichia coli (E. coli) lipopolysaccharide (LPS) can serve as a non-hypoxic stimulus, effectively replicating early periodontal inflammatory reactions. This is evidenced by the upregulation of HIF-1α expression and the activation of HIF-1α-mediated crucial glycolytic enzymes, namely lactate dehydrogenase a, pyruvate kinase, and hexokinase 2, concomitant with an augmentation in the inflammatory response within PDLFs. We observed that the effects mentioned and their impact on macrophage polarization were notably attenuated when intracellular and extracellular stores of Ca2+ were depleted using BAPTA-AM and Ca2+-free medium, respectively. Mechanistically, our findings demonstrated that the transcriptional process of HIF-1α is regulated by Ca2+ during E. coli LPS stimulation, mediated through the signal transducer and activator of transcription 3 (STAT3) pathway. Additionally, we observed that the stabilization of intracellular HIF-1α proteins occurs via the endothelin (ET)-1-endothelin A receptor pathway, independent of hypoxia. Taken together, our research outcomes underscore the pivotal involvement of Ca2+ in the onset of early periodontitis by modulating HIF-1α and glycolysis, thereby presenting novel avenues for early therapeutic interventions.

Aerobic glycolysis of bronchial epithelial cells rewires Mycoplasma pneumoniae pneumonia and promotes bacterial elimination

The immune response to Mycoplasma pneumoniae infection plays a key role in clinical symptoms. Previous investigations focused on the pro-inflammatory effects of leukocytes and the pivotal role of epithelial cell metabolic status in finely modulating the inflammatory response have been neglected. Herein, we examined how glycolysis in airway epithelial cells is affected by M. pneumoniae infection in an in vitro model. Additionally, we investigated the contribution of ATP to pulmonary inflammation. Metabolic analysis revealed a marked metabolic shift in bronchial epithelial cells during M. pneumoniae infection, characterized by increased glucose uptake, enhanced aerobic glycolysis, and augmented ATP synthesis. Notably, these metabolic alterations are orchestrated by adaptor proteins, MyD88 and TRAM. The resulting synthesized ATP is released into the extracellular milieu via vesicular exocytosis and pannexin protein channels, leading to a substantial increase in extracellular ATP levels. The conditioned medium supernatant from M. pneumoniae-infected epithelial cells enhances the secretion of both interleukin (IL)-1β and IL-18 by peripheral blood mononuclear cells, partially mediated by the P2X7 purine receptor (P2X7R). In vivo experiments confirm that addition of a conditioned medium exacerbates pulmonary inflammation, which can be attenuated by pre-treatment with a P2X7R inhibitor. Collectively, these findings highlight the significance of airway epithelial aerobic glycolysis in enhancing the pulmonary inflammatory response and aiding pathogen clearance.

Effect of Short-Chain Fatty Acids on Inflammatory and Metabolic Function in an Obese Skeletal Muscle Cell Culture Model

The fermentation of non-digestible carbohydrates produces short-chain fatty acids (SCFAs), which have been shown to impact both skeletal muscle metabolic and inflammatory function; however, their effects within the obese skeletal muscle microenvironment are unknown. In this study, we developed a skeletal muscle in vitro model to mimic the critical features of the obese skeletal muscle microenvironment using L6 myotubes co-treated with 10 ng/mL lipopolysaccharide (LPS) and 500 µM palmitic acid (PA) for 24 h ± individual SCFAs, namely acetate, propionate and butyrate at 0.5 mM and 2.5 mM. At the lower SCFA concentration (0.5 mM), all three SCFA reduced the secreted protein level of RANTES, and only butyrate reduced IL-6 protein secretion and the intracellular protein levels of activated (i.e., ratio of phosphorylated-total) NFκB p65 and STAT3 (p < 0.05). Conversely, at the higher SCFA concentration (2.5 mM), individual SCFAs exerted different effects on inflammatory mediator secretion. Specifically, butyrate reduced IL-6, MCP-1 and RANTES secretion, propionate reduced IL-6 and RANTES, and acetate only reduced RANTES secretion (p < 0.05). All three SCFAs reduced intracellular protein levels of activated NFκB p65 and STAT3 (p < 0.05). Importantly, only the 2.5 mM SCFA concentration resulted in all three SCFAs increasing insulin-stimulated glucose uptake compared to control L6 myotube cultures (p < 0.05). Therefore, SCFAs exert differential effects on inflammatory mediator secretion in a cell culture model, recapitulating the obese skeletal muscle microenvironment; however, all three SCFAs exerted a beneficial metabolic effect only at a higher concentration via increasing insulin-stimulated glucose uptake, collectively exerting differing degrees of a beneficial effect on obesity-associated skeletal muscle dysfunction.

Optimal compatibility proportional screening of Trichosanthis Pericarpium - Trichosanthis Radix and its anti - Inflammatory components effect on experimental zebrafish and coughing mice

ETHNOPHARMACOLOGICAL RELEVANCE

The herbal pair of Trichosanthis Pericarpium (TP) - Trichosanthis Radix (TR) can be seen in the famous formula "Beimu Gualou San". It is a commonly selected combination of medicinal herbs for the treatment of cough with lung heat. Both drugs are derived from Trichosanthes kirilowii Maxim, a medicinal plant known for its ability to clear heat, resolve phlegm, produce saliva, and alleviate dryness. However, the optimal combination ratio and active ingredients of TP-TR have yet to be determined.

AIM OF THE STUDY

This study aims to investigate the optimal combination ratio of TP-TR and its anti-inflammatory active ingredients in cough treatment.

MATERIALS AND METHODS

A zebrafish (Danio rerio) inflammatory injury model and response surface method were applied in the present study to determine the appropriate proportion of TP-TR. Chemical constituents in TP-TR were identified using HPLC-ELSD and UPLC-MS/MS methods. Subsequently, a cough mouse model was created using an ammonia solution to evaluate the effectiveness of the optimal TP-TR ratio. Network pharmacology and intestinal flora sequencing were used to validate the anti-inflammatory components of TP-TR.

RESULTS

The herbal pair of TP - TR at the ratio of 1:2 showed an optimal anti-inflammatory effect, with a composite inflammatory factor score of 119.645 in the zebrafish experiment. TP-TR combination facilitated the dissolution of glutamine, inosine, cytosine, isoquercetin, and other substances. In the animal model, the TP-TR (1:2) treatment significantly reduced the frequency of coughs and prolonged cough latency compared to the model group. Results of the network pharmacology indicated that inflammatory-related factors such as TLR4, STAT3, EGFR, and AKT1 played crucial roles in cough treatment with TP-TR, consistent with the validation experiment. The 16s rDNA sequencing results revealed a significant increase in the abundance of Clostridia_UCG-014, Lachnospiraceae, Christenella, Ruminococcus, and other species in the intestinal tract of mice after modelling. TP-TR (1:2) reduced the abundance of pro-inflammatory flora such as Clostridium_UCG-014 and Lachnospira, which were closely associated with L-lysine and trans-4-hydroxy-L-proline present in TP-TR according to correlation analysis.

CONCLUSION

TP-TR may promote the dissolution of glutamine, thymidine, inosine, cytosine, isoquercetin, and other components through their combination, thereby regulating the abundance of Clostridium_UCG-014 and Lachnospira and exerting an antitussive effect. This study, for the first time, showed that TP-TR at a 1:2 ratio exhibits superior anti-inflammatory effects. In addition to inflammatory mediators like EGFR, TLR4, AKT1, and STAT3, gut microbes could also serve as potential regulatory targets of TP-TR in the treatment of cough. 2'-Deoxyguanosine monohydrate, L-lysine, L-leucine, γ-aminobutyric acid, L-valine, L-tryptophan, L-proline, trans-4-hydroxy-L-proline, L-methionine, uridine, 2'-deoxyinosine, guanosine, cucurbitacin B and cucurbitacin D were identified as its anti-inflammatory active ingredients.

Isorhamnetin Regulates Programmed Death Ligand-1 Expression by Suppressing the EGFR-STAT3 Signaling Pathway in Canine Mammary Tumors

Programmed death ligand-1 (PD-L1) is highly expressed in a variety of cancer cells and suggests a poorer prognosis for patients. The natural compound isorhamnetin (ISO) shows promise in treating cancers and causing damage to canine mammary tumor (CMT) cells. We investigated the mechanism of ISO in reducing PD-L1 expression in CMT cells. Clustered, regularly interspaced short palindromic repeat-associated protein 9 (CRISPR/Cas9) was used to mediate CD274 knockout in U27 cells. Then, monoclonal cells were screened and cultured. Nucleotide sequencing and expression of PD-L1 were detected. Additionally, we examined cell migration, invasion, and damage. Immunofluorescent staining of PD-L1 was examined in U27 cells. The signaling pathways were measured by Western blotting. Murine xenotransplantation models and murine immunocompetent allograft mammary tumor models were established to evaluate the effect of ISO therapy. Expression of Ki-67, caspase3, and PD-L1 were analyzed by immunohistochemistry. A pull-down assay was used to explore which proteins could bind to ISO. Canine EGFR protein was purified and used to detect whether it directly binds to ISO using a surface plasmon resonance assay. ISO inhibited the EGFR-STAT3-PD-L1 signaling pathway and blocked cancer growth, significantly increasing the survival rate of healthy cells. The cell membrane receptor EGFR was identified as a direct target of ISO. ISO could be exploited as an antineoplastic treatment of CMT by targeting EGFR to suppress PD-L1 expression.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

Ceapin-A7 potentiates lipopolysaccharide-induced endothelial injury

Barrier dysfunction is the hallmark of severe lung injury, including acute respiratory distress syndrome. Efficient medical countermeasures to counteract endothelial hyperpermeability do not exist, hence the mortality rates of disorders related to barrier abnormalities are unacceptable high. The unfolded protein response is a highly conserved mechanism, which aims to support the cells against endoplasmic reticulum stress, and ATF6 is a protein sensor that triggers its activation. In the current study, we investigate the effects of ATF6 suppression in LPS-induced endothelial inflammation. Our observations suggest that Ceapin-A7, which is an ATF6 suppressor, potentiates LPS-induced STAT3 and JAK2 activation. Hence ATF6 activation may serve as a new therapeutic possibility toward diseases related to barrier dysfunction.

RIPK1 and RIPK3 inhibitors: potential weapons against inflammation to treat diabetic complications

Diabetes mellitus is a metabolic disease that is characterized by chronic hyperglycemia due to a variety of etiological factors. Long-term metabolic stress induces harmful inflammation leading to chronic complications, mainly diabetic ophthalmopathy, diabetic cardiovascular complications and diabetic nephropathy. With diabetes complications being one of the leading causes of disability and death, the use of anti-inflammatories in combination therapy for diabetes is increasing. There has been increasing interest in targeting significant regulators of the inflammatory pathway, notably receptor-interacting serine/threonine-kinase-1 (RIPK1) and receptor-interacting serine/threonine-kinase-3 (RIPK3), as drug targets for managing inflammation in treating diabetes complications. In this review, we aim to provide an up-to-date summary of current research on the mechanism of action and drug development of RIPK1 and RIPK3, which are pivotal in chronic inflammation and immunity, in relation to diabetic complications which may be benefit for explicating the potential of selective RIPK1 and RIPK3 inhibitors as anti-inflammatory therapeutic agents for diabetic complications.

Tumour-associated macrophages: versatile players in the tumour microenvironment

Tumour-Associated Macrophages (TAMs) are one of the pivotal components of the tumour microenvironment. Their roles in the cancer immunity are complicated, both pro-tumour and anti-cancer activities are reported, including not only angiogenesis, extracellular matrix remodeling, immunosuppression, drug resistance but also phagocytosis and tumour regression. Interestingly, TAMs are highly dynamic and versatile in solid tumours. They show anti-cancer or pro-tumour activities, and interplay between the tumour microenvironment and cancer stem cells and under specific conditions. In addition to the classic M1/M2 phenotypes, a number of novel dedifferentiation phenomena of TAMs are discovered due to the advanced single-cell technology, e.g., macrophage-myofibroblast transition (MMT) and macrophage-neuron transition (MNT). More importantly, emerging information demonstrated the potential of TAMs on cancer immunotherapy, suggesting by the therapeutic efficiency of the checkpoint inhibitors and chimeric antigen receptor engineered cells based on macrophages. Here, we summarized the latest discoveries of TAMs from basic and translational research and discussed their clinical relevance and therapeutic potential for solid cancers.

A Bidens pilosa L. Non-Polar Extract Modulates the Polarization of Human Macrophages and Dendritic Cells into an Anti-Inflammatory Phenotype

Different communities around the world traditionally use Bidens pilosa L. for medicinal purposes, mainly for its anti-inflammatory, antinociceptive, and antioxidant properties; it is used as an ingredient in teas or herbal medicines for the treatment of pain, inflammation, and immunological disorders. Several studies have been conducted that prove the immunomodulatory properties of this plant; however, it is not known whether the immunomodulatory properties of B. pilosa are mediated by its ability to modulate antigen-presenting cells (APCs) such as macrophages (MØs) and dendritic cells (DCs) (through polarization or the maturation state, respectively). Different polar and non-polar extracts and fractions were prepared from the aerial part of B. pilosa. Their cytotoxic and immunomodulatory effects were first tested on human peripheral blood mononuclear cells (PBMCs) and phytohemagglutinin (PHA)-stimulated PBMCs, respectively, via an MTT assay. Then, the non-cytotoxic plant extracts and fractions that showed the highest immunomodulatory activity were selected to evaluate their effects on human MØ polarization and DC maturation (cell surface phenotype and cytokine secretion) through multiparametric flow cytometry. Finally, the chemical compounds of the B. pilosa extract that showed the most significant immunomodulatory effects on human APCs were identified using gas chromatography coupled with mass spectrometry. The petroleum ether extract and the ethyl acetate and hydroalcoholic fractions obtained from B. pilosa showed low cytotoxicity and modulated the PHA-stimulated proliferation of PBMCs. Furthermore, the B. pilosa petroleum ether extract induced M2 polarization or a hybrid M1/M2 phenotype in MØs and a semi-mature status in DCs, regardless of exposure to a maturation stimulus. The immunomodulatory activity of the non-polar (petroleum ether) extract of B. pilosa on human PBMC proliferation, M2 polarization of MØs, and semi-mature status in DCs might be attributed to the low-medium polarity components in the extract, such as phytosterol terpenes and fatty acid esters.

Janus kinase inhibitors are potential therapeutics for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a poorly treated multifactorial neurodegenerative disease associated with multiple cell types and subcellular organelles. As with other multifactorial diseases, it is likely that drugs will need to target multiple disease processes and cell types to be effective. We review here the role of Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) signalling in ALS, confirm the association of this signalling with fundamental ALS disease processes using the BenevolentAI Knowledge Graph, and demonstrate that inhibitors of this pathway could reduce the ALS pathophysiology in neurons, glia, muscle fibres, and blood cells. Specifically, we suggest that inhibition of the JAK enzymes by approved inhibitors known as Jakinibs could reduce STAT3 activation and modify the progress of this disease. Analysis of the Jakinibs highlights baricitinib as a suitable candidate due to its ability to penetrate the central nervous system and exert beneficial effects on the immune system. Therefore, we recommend that this drug be tested in appropriately designed clinical trials for ALS.

A STAT3 protein complex required for mitochondrial mRNA stability and cancer

Signal transducer and activator of transcription 3 (STAT3) is a potent transcription factor necessary for life whose activity is corrupted in diverse diseases, including cancer. STAT3 biology was presumed to be entirely dependent on its activity as a transcription factor until the discovery of a mitochondrial pool of STAT3, which is necessary for normal tissue function and tumorigenesis. However, the mechanism of this mitochondrial activity remained elusive. This study uses immunoprecipitation and mass spectrometry to identify a complex containing STAT3, leucine-rich pentatricopeptide repeat containing (LRPPRC), and SRA stem-loop-interacting RNA-binding protein (SLIRP) that is required for the stability of mature mitochondrially encoded mRNAs and transport to the mitochondrial ribosome. Moreover, we show that this complex is enriched in patients with lung adenocarcinoma and that its deletion inhibits the growth of lung cancer in vivo, providing therapeutic opportunities through the specific targeting of the mitochondrial activity of STAT3.

FAM3C/ILEI protein is elevated in psoriatic lesions and triggers psoriasiform hyperproliferation in mice

FAM3C/ILEI is an important cytokine for tumor progression and metastasis. However, its involvement in inflammation remains elusive. Here, we show that ILEI protein is highly expressed in psoriatic lesions. Inducible keratinocyte-specific ILEI overexpression in mice (K5-ILEIind ) recapitulates many aspects of psoriasis following TPA challenge, primarily manifested by impaired epidermal differentiation and increased neutrophil recruitment. Mechanistically, ILEI triggers Erk and Akt signaling, which then activates STAT3 via Ser727 phosphorylation. Keratinocyte-specific ILEI deletion ameliorates TPA-induced skin inflammation. A transcriptomic ILEI signature obtained from the K5-ILEIind model shows enrichment in several signaling pathways also found in psoriasis and identifies urokinase as a targetable enzyme to counteract ILEI activity. Pharmacological inhibition of urokinase in TPA-induced K5-ILEIind mice results in significant improvement of psoriasiform symptoms by reducing ILEI secretion. The ILEI signature distinguishes psoriasis from healthy skin with uPA ranking among the top "separator" genes. Our study identifies ILEI as a key driver in psoriasis, indicates the relevance of ILEI-regulated genes for disease manifestation, and shows the clinical impact of ILEI and urokinase as novel potential therapeutic targets in psoriasis.

Paeonol represses A549 cell glycolytic reprogramming and proliferation by decreasing m6A modification of Acyl-CoA dehydrogenase

Aberrant glycolytic reprogramming is involved in lung cancer progression by promoting the proliferation of non-small cell lung cancer cells. Paeonol, as a traditional Chinese medicine, plays a critical role in multiple cancer cell proliferation and inflammation. Acyl-CoA dehydrogenase (ACADM) is involved in the development of metabolic diseases. N6-methyladenosine (m6A) modification is important for the regulation of messenger RNA stability, splicing, and translation. Here, we investigated whether paeonol regulates the proliferation and glycolytic reprogramming via ACADM with m6A modification in A549 cells (human non-small cell lung cancer cells). Cell counting kit 8, 5-Bromo-2-deoxyuridine, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, flow cytometry analysis, western blotting and seahorse XFe24 extracellular flux analyzer assays showed that paeonol had a significant inhibitory effect against A549 cell proliferation and glycolysis. Mechanistically, ACADM was a functional target of paeonol. We also showed that the m6A reader YTH domain containing 1 plays an important role in m6A-modified ACADM expression, which is negatively regulated by paeonol, and is involved in A549 cell proliferation and glycolytic reprogramming. These results indicated the central function of paeonol in regulating A549 cell glycolytic reprogramming and proliferation via m6A modification of ACADM.

Bacterial Lipoproteins Shift Cellular Metabolism to Glycolysis in Macrophages Causing Bone Erosion

Belonging to a group of membrane proteins, bacterial lipoproteins (LPPs) are defined by a unique lipid structure at their N-terminus providing the anchor in the bacterial cell membrane. In Gram-positive bacteria, LPPs play a key role in host immune activation triggered through a Toll-like receptor 2 (TLR2)-mediated action resulting in macrophage stimulation and subsequent tissue damage demonstrated in in vivo experimental models. Yet the physiologic links between LPP activation, cytokine release, and any underlying switches in cellular metabolism remain unclear. In this study, we demonstrate that Staphylococcus aureus Lpl1 not only triggers cytokine production but also confers a shift toward fermentative metabolism in bone marrow-derived macrophages (BMDMs). Lpl1 consists of di- and tri-acylated LPP variants; hence, the synthetic P2C and P3C, mimicking di-and tri-acylated LPPs, were employed to reveal their effect on BMDMs. Compared to P3C, P2C was found to shift the metabolism of BMDMs and the human mature monocytic MonoMac 6 (MM6) cells more profoundly toward the fermentative pathway, as indicated by lactate accumulation, glucose consumption, pH reduction, and oxygen consumption. In vivo, P2C caused more severe joint inflammation, bone erosion, and lactate and malate accumulation than P3C. These observed P2C effects were completely abrogated in monocyte/macrophage-depleted mice. Taken together, these findings now solidly confirm the hypothesized link between LPP exposure, a macrophage metabolic shift toward fermentation, and ensuing bone destruction. IMPORTANCE Osteomyelitis caused by S. aureus is a severe infection of the bone, typically associated with severe bone function impairment, therapeutic failure, high morbidity, invalidity, and occasionally even death. The hallmark of staphylococcal osteomyelitis is the destruction of the cortical bone structures, yet the mechanisms contributing to this pathology are hitherto poorly understood. One bacterial membrane constituent found in all bacteria is bacterial lipoproteins (LPPs). Previously, we have shown that injection of purified S. aureus LPPs into wild-type mouse knee joints caused a TLR2-dependent chronic destructive arthritis but failed to elicit such effect in monocyte/macrophage-depleted mice. This observation stirred our interest in investigating the interaction of LPPs and macrophages and analyzing the underlying physiological mechanisms. This ascertainment of LPP-induced changes in the physiology of macrophages provides an important clue in the understanding of the mechanisms of bone disintegration, opening novel avenues to manage the course of S. aureus disease.

Phosphorylated STAT3 as a potential diagnostic and predictive biomarker in ALK- ALCL vs. CD30high PTCL, NOS

Aims

The differential diagnosis between ALK-negative anaplastic large cell lymphoma (ALK- ALCL) and peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS) with high expression of CD30 (CD30high) are essential. However, no reliable biomarker is available in daily practice except CD30. STAT3 is characteristically activated in ALCL. We aimed to investigate whether the status of STAT3 phosphorylation could help the differential diagnosis.

Methods

The status of phosphorylation of STAT3 was examined using two antibodies against pSTAT3-Y705 and pSTAT3-S727 by immunohistochemistry in ALK+ ALCL (n=33), ALK- ALCL (n=22) and PTCL, NOS (n=34). Ten PTCL, NOS with diffuse CD30 expression were defined as CD30high PTCL, NOS. Flowcytometric analysis were performed to evaluate the expression of pSTAT3-Y705/S727 in PTCL, NOS (n=3).

Results

The median H-scores of pSTAT3-Y705 and S727 were 280 and 260 in ALK+ ALCL, 250 and 240 in ALK- ALCL, and 45 and 75 in CD30high subgroup, respectively. Using H score of 145 as the cutoff value, pSTAT3-S727 alone distinguished between ALK- ALCL and CD30high PTCL, NOS with a sensitivity of 100% and specificity of 83%. Additionally, pSTAT3-S727, but not pSTAT3-Y705, was also expressed by background tumor-infiltrating lymphocytes (S727TILs) in PTCL, NOS. PTCL, NOS patients with high S727TILs H score had a favorable prognosis than those with no TILs (3-year OS rate: 43% vs. 0, p=0.013) or low S727TILs (3-year OS rate: 43% vs. 0, p=0.099). Flowcytometric analysis revealed that of the three patients investigated, two had enhanced pSTAT-S727 signals in neoplastic cell populations, and all three patients were negative for pSTAT3-Y705 expression in both tumor cells and background lymphocytes.

Conclusions

pSTAT3-Y705/S727 can be used to help distinguish ALK- ALCL from CD30high PTCL, NOS and pSTAT3-S727 expression by TILs predicts the prognosis of a subset of PTCL, NOS.

M2 Macrophage-Derived sEV Regulate Pro-Inflammatory CCR2+ Macrophage Subpopulations to Favor Post-AMI Cardiac Repair

Tissue-resident cardiac macrophage subsets mediate cardiac tissue inflammation and repair after acute myocardial infarction (AMI). CC chemokine receptor 2 (CCR2)-expressing macrophages have phenotypical similarities to M1-polarized macrophages, are pro-inflammatory, and recruit CCR2+ circulating monocytes to infarcted myocardium. Small extracellular vesicles (sEV) from CCR2̶ macrophages, which phenotypically resemble M2-polarized macrophages, promote anti-inflammatory activity and cardiac repair. Here, the authors harvested M2 macrophage-derived sEV (M2EV ) from M2-polarized bone-marrow-derived macrophages for intramyocardial injection and recapitulation of sEV-mediated anti-inflammatory activity in ischemic-reperfusion (I/R) injured hearts. Rats and pigs received sham surgery; I/R without treatment; or I/R with autologous M2EV treatment. M2EV rescued cardiac function and attenuated injury markers, infarct size, and scar size. M2EV inhibited CCR2+ macrophage numbers, reduced monocyte-derived CCR2+ macrophage recruitment to infarct sites, induced M1-to-M2 macrophage switching and promoted neovascularization. Analysis of M2EV microRNA content revealed abundant miR-181b-5p, which regulated macrophage glucose uptake, glycolysis, and mitigated mitochondrial reactive oxygen species generation. Functional blockade of miR-181b-5p is detrimental to beneficial M2EV actions and resulted in failure to inhibit CCR2+ macrophage numbers and infarct size. Taken together, this investigation showed that M2EV rescued myocardial function, improved myocardial repair, and regulated CCR2+ macrophages via miR-181b-5p-dependent mechanisms, indicating an option for cell-free therapy for AMI.

p120-Catenin suppresses NLRP3 inflammasome activation in macrophages

Inflammasome activation is of central importance for the process of generation of overwhelming inflammatory response and the pathogenesis of sepsis. The intrinsic molecular mechanism for controlling inflammasome activation is still poorly understood. Here we investigated the role of p120-catenin expression in macrophages in regulating nucleotide-binding oligomerization domain (NOD) and leucine-rich repeat (LRR)- and pyrin domain-containing proteins 3 (NLRP3) inflammasome activation. Depletion of p120-catenin in murine bone marrow-derived macrophages enhanced caspase-1 activation and secretion of active interleukin (IL)-1β in response to ATP stimulation following LPS priming. Coimmunoprecipitation analysis showed that p120-catenin deletion promoted NLRP3 inflammasome activation by accelerating the assembly of the inflammasome complex comprised of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and pro-caspase-1. Depletion of p120-catenin also increased the production of mitochondrial reactive oxygen species. Pharmacological inhibition of mitochondrial reactive oxygen species nearly completely abolished NLRP3 inflammasome activation, caspase-1 activation, and the production of IL-1β in p120-catenin-depleted macrophages. Furthermore, p120-catenin ablation significantly disrupted mitochondrial function, evidenced by decreased mitochondrial membrane potential and lower production of intracellular ATP. In alveolar macrophage-depleted mice challenged with cecal ligation and puncture, pulmonary transplantation of p120-catenin-deficient macrophages dramatically enhanced the accumulation of IL-1β and IL-18 in bronchoalveolar lavage fluid. These results demonstrate that p120-catenin prevents NLRP3 inflammasome activation in macrophages by maintaining mitochondrial homeostasis and reducing the production of mitochondrial reactive oxygen species in response to endotoxin insult. Thus, inhibition of NLRP3 inflammasome activation by stabilization of p120-catenin expression in macrophages may be a novel strategy to prevent an uncontrolled inflammatory response in sepsis.

Crosstalk between oxidative stress and neutrophil response in early ischemic stroke: a comprehensive transcriptome analysis

Background

Ischemic stroke (IS) is the second leading cause of mortality worldwide, continuing to be a serious health concern. It is well known that oxidative stress and neutrophil response play vital roles in the pathophysiology of early IS. However, the complex interactions and critical genes associated with them have not been fully understood.

Methods

Two datasets (GSE37587 and GSE16561) from the Gene Expression Omnibus database were extracted and integrated as the discovery dataset. Subsequent GSVA and WGCNA approaches were used to investigate IS-specific oxidative stress-related genes (ISOSGS). Then, we explored IS-specific neutrophil-associated genes (ISNGS) using CIBERSORT analysis. Next, the protein-protein interaction network was established to ascertain candidate critical genes related with oxidative stress and neutrophil response. Furthermore, these candidate genes were validated using GSE58294 dataset and our clinical samples by RT-qPCR method. Finally, functional annotation, diagnostic capability evaluation and drug-gene interactions were performed by using GSEA analysis, ROC curves and DGIDB database.

Result

In our analysis of discovery dataset, 155 genes were determined as ISOSGS and 559 genes were defined as ISNGS. Afterward, 9 candidate genes were identified through the intersection of ISOSGS and ISNGS, PPI network construction, and filtration by degree algorithm. Then, six real critical genes, including STAT3, MMP9, AQP9, SELL, FPR1, and IRAK3, passed the validation using the GSE58294 dataset and our clinical samples. Further functional annotation analysis indicated these critical genes were associated with neutrophil response, especially neutrophil extracellular trap. Meanwhile, they had a good diagnostic performance. Lastly, 53 potential drugs targeting these genes were predicted by DGIDB database.

Conclusion

We identified 6 critical genes, STAT3, FPR1, AQP9, SELL, MMP9 and IRAK3, related to oxidative stress and neutrophil response in early IS, which may provide new insights into understanding the pathophysiological mechanism of IS. We hope our analysis could help develop novel diagnostic biomarkers and therapeutic strategies for IS.

Mitochondrial dynamics in macrophages: divide to conquer or unite to survive?

Mitochondria have long been appreciated as the metabolic hub of cells. Emerging evidence also posits these organelles as hubs for innate immune signalling and activation, particularly in macrophages. Macrophages are front-line cellular defenders against endogenous and exogenous threats in mammals. These cells use an array of receptors and downstream signalling molecules to respond to a diverse range of stimuli, with mitochondrial biology implicated in many of these responses. Mitochondria have the capacity to both divide through mitochondrial fission and coalesce through mitochondrial fusion. Mitochondrial dynamics, the balance between fission and fusion, regulate many cellular functions, including innate immune pathways in macrophages. In these cells, mitochondrial fission has primarily been associated with pro-inflammatory responses and metabolic adaptation, so can be considered as a combative strategy utilised by immune cells. In contrast, mitochondrial fusion has a more protective role in limiting cell death under conditions of nutrient starvation. Hence, fusion can be viewed as a cellular survival strategy. Here we broadly review the role of mitochondria in macrophage functions, with a focus on how regulated mitochondrial dynamics control different functional responses in these cells.

Innate sensing and cellular metabolism: role in fine tuning antiviral immune responses

Several studies over the last decade have identified intimate links between cellular metabolism and macrophage function. Metabolism has been shown to both drive and regulate macrophage function by producing bioenergetic and biosynthetic precursors as well as metabolites (and other bioactive molecules) that regulate gene expression and signal transduction. Many studies have focused on lipopolysaccharide-induced reprogramming, assuming that it is representative of most inflammatory responses. However, emerging evidence suggests that diverse pathogen-associated molecular patterns (PAMPs) are associated with unique metabolic profiles, which may drive pathogen specific immune responses. Further, these metabolic pathways and processes may act as a rheostat to regulate the magnitude of an inflammatory response based on the biochemical features of the local microenvironment. In this review, we will discuss recent work examining the relationship between cellular metabolism and macrophage responses to viral PAMPs and describe how these processes differ from lipopolysaccharide-associated responses. We will also discuss how an improved understanding of the specificity of these processes may offer new insights to fine-tune macrophage function during viral infections or when using viral PAMPs as therapeutics.

HDAC1 disrupts the tricarboxylic acid (TCA) cycle through the deacetylation of Nur77 and promotes inflammation in ischemia-reperfusion mice

Histone deacetylase enzymes (HDACs) regulate protein acetylation. HDAC1 is known to enhance ischemia/reperfusion (I/R) injury, but its underlying mechanism(s) of action have not been defined. Here, in vivo mouse models of myocardial I/R were used to investigate the role of HDAC1 during I/R myocardial injury. We show that HDAC1 enhances the inflammatory responses of I/R mice. Using a constructed macrophage H/R (hypoxia/ regeneration) injury model (Raw264.7 cells), we identified Nur77 as a HDAC1 target in macrophages. Nur77 deficient macrophages failed to downregulate IDH1 (isocitrate dehydrogenase 1) and accumulated succinic acid and other tricarboxylic acid (TCA) cycle-derived metabolites in a glutamine-independent manner. These data show that the inhibition of HDAC1 ameliorates H/R-inflammation in macrophages through the regulation of Nur77 and the TCA cycle.

Physiological mechanisms of TLR4 in glucolipid metabolism regulation: Potential use in metabolic syndrome prevention

Over-nourishment or an unbalanced diet has been linked to an increase in the prevalence of metabolic syndrome. An imbalance in glucolipid metabolism is a major cause of metabolic syndrome, which has consequences for human health. Toll-like receptor 4 (TLR4), a member of the innate immune pattern recognition receptor family, is involved in inflammation-related disorders, autoimmune diseases, and tumors. Recent research has shown that TLR4 plays a key role in glucolipid metabolism, which is linked to insulin resistance, intestinal flora, and the development of chronic inflammation. TLR4 activation regulates glucolipid metabolism and contributes to the dynamic relationship between innate immunity and nutrition-related disorders. Further, TLR4 regulates glucolipid metabolism by controlling glycolysis and pyruvate oxidative decarboxylation, interfering with insulin signaling, regulating adipogenic gene expression levels, influencing preadipocyte differentiation and lipid accumulation, and altering the intestinal microbiota and permeability. TLR4 functions may provide new therapeutic applications for the prevention and treatment of metabolic syndrome. The purpose of this review is to enrich mechanistic research of diabetes, atherosclerosis, and other nutrition-related disorders by summarizing the role of TLR4 in the regulation of glucolipid metabolism as well as its physiological mechanisms.

Rapid glycolytic activation accompanying innate immune responses: mechanisms and function

Innate immune responses to pathogens, mediated by activation of pattern recognition receptors and downstream signal transduction cascades, trigger rapid transcriptional and epigenetic changes to support increased expression of pro-inflammatory cytokines and other effector molecules. Innate immune cells also rapidly rewire their metabolism. The most prominent metabolic alteration following innate immune activation is rapid up-regulation of glycolysis. In this mini-review, we summarize recent advances regarding the mechanisms of rapid glycolytic activation in innate immune cells, highlighting the relevant signaling components. We also discuss the impact of glycolytic activation on inflammatory responses, including the recently elucidated links of metabolism and epigenetics. Finally, we highlight unresolved mechanistic details of glycolytic activation and possible avenues of future research in this area.

GSK3β Inhibition by Phosphorylation at Ser389 Controls Neuroinflammation

The inhibition of Glycogen Synthase Kinase 3 β (GSK3β) by Ser⁹ phosphorylation affects many physiological processes, including the immune response. However, the consequences of GSK3β inhibition by alternative Ser³⁸⁹ phosphorylation remain poorly characterized. Here we have examined neuroinflammation in GSK3β Ser³⁸⁹ knock-in (KI) mice, in which the phosphorylation of Ser³⁸⁹ GSK3β is impaired. The number of activated microglia/infiltrated macrophages, astrocytes, and infiltrated neutrophils was significantly higher in these animals compared to C57BL/6J wild-type (WT) counterparts, which suggests that the failure to inactivate GSK3β by Ser³⁸⁹ phosphorylation results in sustained low-grade neuroinflammation. Moreover, glial cell activation and brain infiltration of immune cells in response to lipopolysaccharide (LPS) failed in GSK3β Ser³⁸⁹ KI mice. Such effects were brain-specific, as peripheral immunity was not similarly affected. Additionally, phosphorylation of the IkB kinase complex (IKK) in response to LPS failed in GSK3β Ser³⁸⁹ KI mice, while STAT3 phosphorylation was fully conserved, suggesting that the NF-κB signaling pathway is specifically affected by this GSK3β regulatory pathway. Overall, our findings indicate that GSK3β inactivation by Ser³⁸⁹ phosphorylation controls the brain inflammatory response, raising the need to evaluate its role in the progression of neuroinflammatory pathologies.

Programmed death ligand 1 intracellular interactions with STAT3 and focal adhesion protein Paxillin facilitate lymphatic endothelial cell remodeling

Lymphatic endothelial cells (LECs) comprise lymphatic capillaries and vessels that guide immune cells to lymph nodes (LNs) and form the subcapsular sinus and cortical and medullary lymphatic structures of the LN. During an active immune response, the lymphatics remodel to accommodate the influx of immune cells from the tissue, but factors involved in remodeling are unclear. Here, we determined that a TSS motif within the cytoplasmic domain of programmed death ligand 1 (PD-L1), expressed by LECs in the LN, participates in lymphatic remodeling. Mutation of the TSS motif to AAA does not affect surface expression of PD-L1, but instead causes defects in LN cortical and medullary lymphatic organization following immunostimulant, Poly I:C, administration in vivo. Supporting this observation, in vitro treatment of the LEC cell line, SVEC4-10, with cytokines TNFα and IFNα significantly impeded SVEC4-10 movement in the presence of the TSS-AAA cytoplasmic mutation. The cellular movement defects coincided with reduced F-actin polymerization, consistent with differences previously found in dendritic cells. Here, in addition to loss of actin polymerization, we define STAT3 and Paxillin as important PD-L1 binding partners. STAT3 and Paxillin were previously demonstrated to be important at focal adhesions for cellular motility. We further demonstrate the PD-L1 TSS-AAA motif mutation reduced the amount of pSTAT3 and Paxillin bound to PD-L1 both before and after exposure to TNFα and IFNα. Together, these findings highlight PD-L1 as an important component of a membrane complex that is involved in cellular motility, which leads to defects in lymphatic organization.

Major pathways involved in macrophage polarization in cancer

Macrophages play an important role in tissue homeostasis, tissue remodeling, immune response, and progression of cancer. Consequently, macrophages exhibit significant plasticity and change their transcriptional profile and function in response to environmental, tissue, and inflammatory stimuli resulting in pro- and anti-tumor effects. Furthermore, the categorization of tissue macrophages in inflammatory situations remains difficult; however, there is an agreement that macrophages are predominantly polarized into two different subtypes with pro- and anti-inflammatory properties, the so-called M1-like and M2-like macrophages, respectively. These two macrophage classes can be considered as the extreme borders of a continuum of many intermediate subsets. On one end, M1 are pro-inflammatory macrophages that initiate an immunological response, damage tissue integrity, and dampen tumor progression by fostering robust T and natural killer (NK) cell anti-tumoral responses. On the other end, M2 are anti-inflammatory macrophages involved in tissue remodeling and tumor growth, that promote cancer cell proliferation, invasion, tumor metastasis, angiogenesis and that participate to immune suppression. These decisive roles in tumor progression occur through the secretion of cytokines, chemokines, growth factors, and matrix metalloproteases, as well as by the expression of immune checkpoint receptors in the case of M2 macrophages. Moreover, macrophage plasticity is supported by stimuli from the Tumor Microenvironment (TME) that are relayed to the nucleus through membrane receptors and signaling pathways that result in gene expression reprogramming in macrophages, thus giving rise to different macrophage polarization outcomes. In this review, we will focus on the main signaling pathways involved in macrophage polarization that are activated upon ligand-receptor recognition and in the presence of other immunomodulatory molecules in cancer.

Metabolic and Nonmetabolic Functions of PSAT1 Coordinate Signaling Cascades to Confer EGFR Inhibitor Resistance and Drive Progression in Lung Adenocarcinoma

Emerging evidence demonstrates that the dysregulated metabolic enzymes can accelerate tumorigenesis and progression via both metabolic and nonmetabolic functions. Further elucidation of the role of metabolic enzymes in EGFR inhibitor resistance and metastasis, two of the leading causes of death in lung adenocarcinoma, could help improve patient outcomes. Here, we found that aberrant upregulation of phosphoserine aminotransferase 1 (PSAT1) confers erlotinib resistance and tumor metastasis in lung adenocarcinoma. Depletion of PSAT1 restored sensitivity to erlotinib and synergistically augmented the tumoricidal effect. Mechanistically, inhibition of PSAT1 activated the ROS-dependent JNK/c-Jun pathway to induce cell apoptosis. In addition, PSAT1 interacted with IQGAP1, subsequently activating STAT3-mediated cell migration independent of its metabolic activity. Clinical analyses showed that PSAT1 expression positively correlated with the progression of human lung adenocarcinoma. Collectively, these findings reveal the multifunctionality of PSAT1 in promoting tumor malignancy through its metabolic and nonmetabolic activities.

SIGNIFICANCE

Metabolic and nonmetabolic functions of PSAT1 confer EGFR inhibitor resistance and promote metastasis in lung adenocarcinoma, suggesting therapeutic targeting of PSAT1 may attenuate the malignant features of lung cancer.

STAT3 transcriptionally regulates the expression of genes related to glycogen metabolism in developing motor neurons

Motor neurons in the spinal cord are essential for movement. During the embryonic period, developing motor neurons store glycogen to protect against hypoglycemic and hypoxic stress. However, the mechanisms by which glycogen metabolism is regulated in motor neurons remain unclear. We herein investigated the transcriptional regulation of genes related to glycogen metabolism in the developing spinal cord. We focused on the regulatory mechanism of glycogen synthase (Gys1) and glycogen phosphorylase brain isoform (PygB), which play central roles in glycogen metabolism, and found that the transcription factor STAT3 regulated the expression of Gys1 and PygB via cis-regulatory promoter sequences in the developing spinal cord. These results suggest that STAT3 is important for the regulation of glycogen metabolism during motor neuron development.

Formyl-Peptide Receptor 2 Signaling Redirects Glucose and Glutamine into Anabolic Pathways in Metabolic Reprogramming of Lung Cancer Cells

Glucose and glutamine play a crucial role in the metabolic reprogramming of cancer cells. Proliferating cells metabolize glucose in the aerobic glycolysis for energy supply, and glucose and glutamine represent the primary sources of carbon atoms for the biosynthesis of nucleotides, amino acids, and lipids. Glutamine is also an important nitrogen donor for the production of nucleotides, amino acids, and nicotinamide. Several membrane receptors strictly control metabolic reprogramming in cancer cells and are considered new potential therapeutic targets. Formyl-peptide receptor 2 (FPR2) belongs to a small family of GPCRs and is implicated in many physiopathological processes. Its stimulation induces, among other things, NADPH oxidase-dependent ROS generation that, in turn, contributes to intracellular signaling. Previously, by phosphoproteomic analysis, we observed that numerous proteins involved in energetic metabolism are uniquely phosphorylated upon FPR2 stimulation. Herein, we investigated the role of FPR2 in cell metabolism, and we observed that the concentrations of several metabolites associated with the pentose phosphate pathway (PPP), tricarboxylic acid cycle, nucleotide synthesis, and glutamine metabolism, were significantly enhanced in FPR2-stimulated cells. In particular, we found that the binding of specific FPR2 agonists: (i) promotes NADPH production; (ii) activates the non-oxidative phase of PPP; (iii) induces the expression of the ASCT2 glutamine transporter; (iv) regulates oxidative phosphorylation; and (v) induces the de novo synthesis of pyrimidine nucleotides, which requires FPR2-dependent ROS generation.

Amelioration of TPA-induced skin inflammation by the leaf extract of Vernonia amygdalina involves ERK/STAT3 (Ser727) signaling inhibition

BACKGROUND

Uncontrolled inflammation causes health problems. Extracellular signal-regulated kinase (ERK) phosphorylates signal transducer and activator of transcription 3 (STAT3) at Ser727, resulting in inflammation. The leaf of Vernonia amygdalina (VA) is a medicinal herb for managing inflammation-associated diseases. Oral administration or topical application of VA leaf extract exerts anti-inflammatory effects in rat models. However, the anti-inflammatory mechanisms of the herb are not fully understood.

PURPOSE

In this study, we aimed to investigate the involvement of ERK/STAT3 (Ser727) signaling in the anti-inflammatory effects of an ethanolic extract of VA leaves.

STUDY DESIGN AND METHODS

Extracts of VA leaves were prepared with different concentrations of ethanol. A LPS-stimulated RAW264.7 cell model was used for in vitro assays, and a TPA (12-O-tetradecanoylphorbol-13-acetate)-induced ear edema mouse model was employed for in vivo assays. The 95% ethanol extract of VA leaves (VAE) exerted the strongest inhibitory effect on nitric oxide (NO) production in LPS-stimulated macrophages; thus it was selected for use in this study. Hematoxylin and eosin (H&E) staining was used to examine pathological conditions of mouse ear tissues. Griess reagent was employed to examine NO generation in cell cultures. Immunoblotting and ELISA were used to examine protein levels, and RT-qPCR was employed to examine mRNA levels.

RESULTS

Topical application of VAE ameliorated mouse ear edema induced by TPA. VAE suppressed the phosphorylation of ERK (Thr202/Tyr204) and STAT3 (Ser727); and decreased protein levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, IL-1β and tumor necrosis factor-α (TNF-α) in the mouse ear tissues and in LPS-stimulated RAW 264.7 cells. VAE also inhibited NO production, and lowered mRNA levels of IL-6, IL-1β and TNF-α in the macrophages.

CONCLUSIONS

VAE ameliorates TPA-induced mouse ear edema. Suppression of ERK/STAT3 (Ser727) signaling is involved in VAE's anti-inflammatory effects. These novel data provide further pharmacological justifications for the medicinal use of VA in treating inflammation-associated diseases, and lay the groundwork for developing VAE into a new anti-inflammatory agent.

Differential Effects of Short-Chain Fatty Acids on L6 Myotube Inflammatory Mediator Production in Response to Lipopolysaccharide- or Palmitic Acid-Stimulation

Short-chain fatty acids (SCFA) produced from dietary non-digestible carbohydrate fermentation have metabolic effects in skeletal muscle; however, their effect on inflammatory mediator production is unknown. In this study, L6 myotubes were cultured with individual SCFA (acetate, propionate, and butyrate) at 0.5 mM and 2.5 mM ± 10 ng/mL lipopolysaccharide (LPS) or ± 500 µM palmitic acid (PA) for 24 h. In response to LPS, only butyrate had an effect at the lower concentration (0.5 mM), whereas at the higher concentration (2.5 mM) both propionate and butyrate reduced MCP-1, MIP-1α, and RANTES secretion (p < 0.05), and only butyrate reduced IL-6 secretion and intracellular protein levels of phospho-STAT3 (p < 0.05). In response to PA, 0.5 mM butyrate reduced protein expression of phospho-NFκB p65 and the secretion of IL-6, MIP-1α, and MCP-1, whereas all three SCFA reduced RANTES secretion (p < 0.05). At the 2.5 mM SCFA concentration combined with PA stimulation, all three SCFA reduced intracellular protein expression of phospho-NFκB p65 and phospho-STAT3 and secreted protein levels of MCP-1, IL-6, and RANTES, whereas only butyrate reduced secretion of MIP-1α (p < 0.05). Thus, SCFA exhibit differential effects on inflammatory mediator expression in response to LPS and PA stimulation, which has implications for their individual impacts on inflammation-mediated skeletal muscle dysfunction.