STAT3 Activator Research Articles

SIRT3 Activator Honokiol Inhibits Th17 Cell Differentiation and Alleviates Colitis.

Honokiol (HKL), a natural extract of the bark of the magnolia tree and an activator of the mitochondrial protein sirtuin-3 (SIRT3), has been proposed to possess anti-inflammatory effects. This study investigated the inhibitory effects of HKL on T helper (Th) 17 cell differentiation in colitis. Serum and biopsies from 20 participants with ulcerative colitis (UC) and 18 healthy volunteers were collected for the test of serum cytokines, flow cytometry analysis (FACS), and relative messenger RNA (mRNA) levels of T cell subsets, as well as the expression of SIRT3 and phosphorylated signal transducer and activator of transcription/retinoic acid-related orphan nuclear receptor γt (p-STAT3/RORγt) signal pathway in colon tissues. In vitro, naïve clusters of differentiation (CD) 4 + T cells isolated from the mouse spleen differentiated to subsets including Th1, Th2, Th17, and regulatory T (Treg) cells. Peripheral blood monocytes (PBMCs) from healthy volunteers were induced to the polarization of Th17 cells. After HKL treatment, changes in T cell subsets, related cytokines, and transcription factors were measured. The dextran sulfate sodium (DSS)-induced colitis and interleukin (IL)-10-deficient mice were intraperitoneally injected with HKL. These experiments were conducted to study the effect of HKL on the development, cytokines, and expression of signaling pathway proteins in colitis. Patients with UC had higher serum IL-17 and a higher proportion of Th17 differentiation in blood compared with healthy participants; while IL-10 level and the proportion of Treg cells were lower. Higher relative mRNA levels of RORγt and a lower SIRT3 expression in colon tissues were observed. In vitro, HKL had little effect on the differentiation of naïve CD4+ T cells to Th1, Th2, or Treg cells, but it downregulated IL-17 levels and the Th17 cell ratio in CD4+ T cells from the mouse spleen and human PBMCs under Th17 polarization. Even with a STAT3 activator, HKL still significantly inhibited IL-17 levels. In DSS-induced colitis mice and IL-10 deficient mice treated with HKL, the length of the colon, weight loss, disease activity index, and histopathological scores were improved, IL-17 and IL-21 levels, and the proportion of Th17 cells were decreased. Sirtuin-3 expression was increased, whereas STAT3 phosphorylation and RORγt expression were inhibited in the colon tissue of mice after HKL treatment. Our study demonstrated that HKL could partially protect against colitis by regulating Th17 differentiation through activating SIRT3, leading to inhibition of the STAT3/RORγt signaling pathway. These results provide new insights into the protective effects of HKL against colitis and may facilitate the research of new drugs for inflammatory bowel disease.

Baicalein Attenuates Neuroinflammation in LPS-Treated BV-2 Cells by Inhibiting Glycolysis via STAT3/c-Myc Pathway.

More and more evidence shows that metabolic reprogramming is closely related to the occurrence of AD. The metabolic conversion of oxidative phosphorylation into glycolysis will aggravate microglia-mediated inflammation. It has been demonstrated that baicalein could inhibit neuroinflammation in LPS-treated BV-2 microglial cells, but whether the anti-neuroinflammatory mechanisms of baicalein were related to glycolysis is unclear. Our results depicted that baicalein significantly inhibited the levels of nitric oxide (NO), interleukin-6 (IL-6), prostaglandin 2 (PGE2) and tumor necrosis factor (TNF-α) in LPS-treated BV-2 cells. 1H-NMR metabolomics analysis showed that baicalein decreased the levels of lactic acid and pyruvate, and significantly regulated glycolytic pathway. Further study revealed that baicalein significantly inhibited the activities of glycolysis-related enzymes including hexokinase (HK), 6-phosphate kinase (6-PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), and inhibited STAT3 phosphorylation and c-Myc expression. By using of STAT3 activator RO8191, we found that baicalein suppressed the increase of STAT3 phosphorylation and c-Myc expression triggered by RO8191, and inhibited the increased levels of 6-PFK, PK and LDH caused by RO8191. In conclusion, these results suggested that baicalein attenuated the neuroinflammation in LPS-treated BV-2 cells by inhibiting glycolysis through STAT3/c-Myc pathway.

AhR agonist tapinarof ameliorates lupus autoimmunity by suppressing Tfh cell differentiation via regulation of the JAK2-STAT3 signaling pathway.

The aryl hydrocarbon receptor (AhR) is a critical regulator of the pathogenesis of autoimmune disorders. We aimed to investigate the therapeutic effect of the AhR agonist tapinarof during the development of systemic lupus erythematosus (SLE). MRL/lpr mice were intraperitoneally injected with 1 or 5 mg/kg tapinarof for 6 weeks. Kidney histopathology was evaluated using hematoxylin and eosin (H&E) and Periodic-Acid-Schiff (PAS) staining. Immunofluorescence microscopy was performed to detect immune complex renal depositions. Flow cytometry (FCM) analysis was carried out to determine the proportions of T and B cell subsets. Realtime qPCR was used to quantify the expression of Tfh cell-associated genes. We conducted an in vitro polarization experiment to observe the effect of tapinarof on Tfh differentiation. Western blotting was used to detect the expression of target proteins. We found that tapinarof treatment ameliorated lupus phenotypes, including splenomegaly, lymph node enlargement, kidney damages, immune complex deposition, and excessive secretion of antibodies. Additionally, we showed that Treg subpopulation frequencies significantly increased in MRL/lpr mice treated with tapinarof, while the proportion of Th1/Th2 cells was reduced after tapinarof administration. Moreover, tapinarof suppressed Tfh cell differentiation and germinal center (GC) reaction in vivo. The inhibitory effect of tapinarof on Tfh cells was further verified in the in vitro Tfh cell polarization experiment. Realtime qPCR revealed that tapinarof repressed the expression of Tfh signature genes. Mechanistically, tapinarof significantly inhibited the phosphorylation levels of JAK2 and STAT3. The capacity for Tfh differentiation was partially rescued by the STAT3 activator Colivelin TFA. Furthermore, our in vitro Tfh polarization experiments indicated that tapinarof suppressed Tfh cell development in SLE. Our data demonstrated that tapinarof modulated the JAK2-STAT3 pathway to suppress Tfh cell differentiation for the treatment of lupus symptoms in MRL/lpr mice.

Unfolded protein response factor ATF6 augments T helper cell responses and promotes mixed granulocytic airway inflammation

The unfolded protein response (UPR) is associated with the risk of asthma, including treatment-refractory severe asthma. Recent studies demonstrated a pathogenic role of activating transcription factor 6a (ATF6a or ATF6), an essential UPR sensor, in airway structural cells. However, its role in T helper (TH) cells has not been well examined. In this study, we found that ATF6 was selectively induced by signal transducer and activator of transcription6 (STAT6) and STAT3 in TH2 and TH17 cells, respectively. ATF6 upregulated UPR genes and promoted the differentiation and cytokine secretion of TH2 and TH17 cells. T cell-specific Atf6-deficiency impaired TH2 and TH17 responses in vitro and in vivo and attenuated mixed granulocytic experimental asthma. ATF6 inhibitor Ceapin A7 suppressed the expression of ATF6 downstream genes and TH cell cytokines by both murine and human memory clusters of differentiation 4 (CD4)+ T cells. At the chronic stage of asthma, administration of Ceapin A7 lessened TH2 and TH17 responses, leading to alleviation of both airway neutrophilia and eosinophilia. Thus, our results demonstrate a critical role of ATF6 in TH2 and TH17 cell-driven mixed granulocytic airway disease, suggesting a novel option to combat steroid-resistant mixed and even T2-low endotypes of asthma by targeting ATF6.

Disturbance of sleep maintenance, but not sleep duration, activates nuclear factor-κB and signal transducer and activator of transcription family proteins in older adults: sex differences.

Disturbances of sleep maintenance and sleep duration are common in older adults and associated with an increased risk for age-related mortality and morbidity. Converging evidence implicates inflammation as an underlying mechanism, especially in females. However, it is unknown what specific aspects of sleep disturbance impact inflammatory mechanisms in older adults. Using data from community-dwelling older adults who participated in the Sleep Health and Aging Research (SHARE) field study (n = 262, mean age 71.9 ± 8.0 years), we conducted a secondary analysis to examine whether disturbance of sleep maintenance (i.e. greater amount of wake time after sleep onset [WASO]) and sleep duration (i.e. shorter total sleep time [TST]) assessed by sleep diary and actigraphy are associated with greater activation of nuclear factor (NF)-κB and signal transducer and activator of transcription (STAT) family proteins STAT1, STAT3, and STAT5 in peripheral blood monocytic cells. In addition, moderation effects of sex were explored. Data were available for sleep diary (n = 82), actigraphy (n = 74), and inflammatory signaling and transcriptional measures (n = 132). As assessed by sleep diary, greater amount of WASO (β = 0.39, p < 0.01), but not TST, was associated with higher levels of NF-κB. Whereas diary-assessed sleep measures were not associated with STAT family proteins, a moderation analysis revealed that greater diary-assessed WASO was associated with higher levels of STAT1 (p < 0.05), STAT3 (p < 0.05), and STAT5 (p < 0.01) in females, but not in males. Actigraphy-assessed sleep measures were not associated either with NF-κB or STAT activation. In older adults, self-reported disturbance of sleep maintenance assessed by sleep diary was uniquely associated with higher levels of NF-κB, along with higher levels of STAT family proteins in females, but not in males. Our data suggest that improvingself-reported sleep maintenance might mitigate age-related increases in inflammatory signaling and transcriptional pathways, possibly more strongly in females, with the potential to reduce mortality risk in older adults.

Steady-state memory-phenotype conventional CD4+ T cells exacerbate autoimmune neuroinflammation in a bystander manner via the Bhlhe40/GM-CSF axis

Memory-phenotype (MP) CD4+ T cells are a substantial population of conventional T cells that exist in steady-state mice, yet their immunological roles in autoimmune disease remain unclear. In this work, we unveil a unique phenotype of MP CD4+ T cells determined by analyzing single-cell transcriptomic data and T cell receptor (TCR) repertoires. We found that steady-state MP CD4+ T cells in the spleen were composed of heterogeneous effector subpopulations and existed regardless of germ and food antigen exposure. Distinct subpopulations of MP CD4+ T cells were specifically activated by IL-1 family cytokines and STAT activators, revealing that the cells exerted TCR-independent bystander effector functions similar to innate lymphoid cells. In particular, CCR6high subpopulation of MP CD4+ T cells were major responders to IL-23 and IL-1β without MOG35-55 antigen reactivity, which gave them pathogenic Th17 characteristics and allowed them to contribute to autoimmune encephalomyelitis. We identified that Bhlhe40 in CCR6high MP CD4+ T cells as a key regulator of GM-CSF expression through IL-23 and IL-1β signaling, contributing to central nervous system (CNS) pathology in experimental autoimmune encephalomyelitis. Collectively, our findings reveal the clearly distinct effector-like heterogeneity of MP CD4+ T cells in the steady state and indicate that CCR6high MP CD4+ T cells exacerbate autoimmune neuroinflammation via the Bhlhe40/GM-CSF axis in a bystander manner.

Investigating in vitro NF-κB and STAT3 activation in MOGAD (S40.010)

<h3>Objective:</h3> To investigate the in vitro activation of NF-κB (nuclear factor kappa B) and STAT3 pathways in central memory CD4+ T (CD45RACD62L+, Tcm) cells of MOGAD patients after antigen and cytokine stimulation or glucocorticoid treatment compared to age-matched healthy controls (HC). <h3>Background:</h3> There is increasing evidence that T cells play a key role in MOGAD. Proinflammatory cytokines IL6 and TNFα, activators of STAT3 and NF-κB pathways, respectively, are reported to increase in CSF of MOGAD patients and increase during infections, which commonly precede MOGAD relapses, We previously found decreased A20, a negative regulator of NF-κB, serum levels at relapse. <h3>Design/Methods:</h3> 4 pediatric MOGAD remission samples (untreated) and 4 sex and age-matched HC were studied. 8×10⁴ PBMCs were plated per well. Cells were stimulated with MOG peptides, anti-CD3/CD28, TNFα, IL6, or PMA/Ionomycin. A20, IκBα (inhibitor kappa B-alpha), p-p65 (phospho-p65), and p-STAT3 (phospho-STAT3) expression levels (MFI, mean fluorescence intensity) were determined by flow cytometry and MFI levels in Tcm. <h3>Results:</h3> Ex vivo expression levels of A20, IκBα, p-p65, and p-STAT3 levels were not significantly different in MOGAD compared to HC in Tcm. Upon short IL6 or TNFα (0–15/7–75 minutes) stimulation, we observed similar NF-κB and STAT3 activation in the Tcm, while STAT3 activation was significantly higher at 75 minutes in MOGAD. MOG peptide stimulation for 24 hours decreased A20 and IκBα levels and increased p-STAT3 and p-p65 levels in both MOGAD and HC. When co-incubated with either MOG peptide or CD3, prednisolone decreased NF-κB and STAT3 activation. <h3>Conclusions:</h3> MOG peptide stimulation activates STAT3 and NF-κB in CD4+Tcm cells from MOGAD and HC, while prednisolone treatment had the opposite effect. IL6 and TNFα also activate Tcm similarly in MOGAD and HC, while STAT3 activation was more extended in MOGAD. Modulating the NF-κB-A20 or IL6/STAT3 pathway in T cells may have therapeutic potential in MOGAD. <b>Disclosure:</b> Mr. Corbali has nothing to disclose. Shrishti Saxena has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Chitnis has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. Dr. Chitnis has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Roche-Genentech. Dr. Chitnis has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Academic CME. The institution of Dr. Chitnis has received research support from Novartis. The institution of Dr. Chitnis has received research support from Sanofi. The institution of Dr. Chitnis has received research support from Octave.

Adenosine-ADORA2A Promotes Ang-Induced Angiogenesis in Intrauterine Growth Restriction Placenta via the Stat3/Akt Pathway.

Abnormal placental angiogenesis is an important cause of fetal intrauterine growth restriction (IUGR), but its underlying mechanisms and therapies remain unclear. Adenosine and its mediated signaling has been reported to be associated with the development of angiogenesis. However, whether the adenosine-related signaling plays a role in modulating angiogenesis in placenta and the IUGR pregnancy outcomes remains unclear. The angiogenesis and adenosine signaling expressions in normal and IUGR placentas were detected in different species. And the role of adenosine in regulating IUGR pregnancy outcomes was evaluated using diet-induced IUGR mouse model. Molecular mechanisms underlying adenosine-induced angiogenesis were investigated by in vitro angiogenesis assays and in vivo Matrigel plug assays. Here, we demonstrated poor angiogenesis and low adenosine concentration and downregulated expression of its receptor A2a (ADORA2A [adenosine A2a receptor]) in IUGR placenta. Additionally, the beneficial effects of adenosine in improving IUGR pregnancy outcomes were revealed in a diet-induced IUGR mouse model. Moreover, adenosine was found to effectively improve adenosine signaling and angiogenesis in IUGR mice placenta. Mechanistically, by using angiogenesis assays in vitro and in vivo, adenosine was shown to activate ADORA2A to promote the phosphorylation of Stat3 (signal transducer and activator of transcription 3) and Akt (protein kinase B), resulting in increased Ang (angiogenin)-dependent angiogenesis. Collectively, this study uncovers an unexpected mechanism of promoting placental angiogenesis by adenosine-ADORA2A signaling and advances the translation of this signaling as a prognostic indicator and therapeutic target in IUGR treatment.

Correlation of signal transducer and activator of transcription-3 andβ-catenin expression in laryngeal squamous cell carcinoma

The specific roles of phosphorylated signal transducer and activator of transcription-3 (p-STAT3) and β-Catenin in laryngeal squamous cell carcinoma (LSCC) remain unclear. In this study, the correlations between p-STAT3, β-Catenin, and clinicopathological characteristics were investigated using tissues and clinical data from 124 LSCC cases. Immunohistochemistry and immunofluorescence assays were used to examine p-STAT3 and β-Catenin expression and localization in these samples. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognostic significance of these proteins. LSCC cell lines were treated with a STAT3 inhibitor (dihydroartemisinin) or activator (interleukin-6) to explore the mechanism of p-STAT3 and β-Catenin. There was an inverse correlation between p-STAT3 and β-Catenin expression in the LSCC samples. Patients with high p-STAT3 and low β-Catenin expression levels had significantly worse overall survival. Multivariate Cox regression analysis revealed that lymph node metastasis and β-Catenin expression were both independently correlated with unfavorable overall survival. Cell treatment with the p-STAT3 inhibitor inhibited the nuclear accumulation of β-Catenin, while p-STAT3 activator treatment could promote β-Catenin translocation to the nucleus. Overall, our data indicate that p-STAT3 expression is associated with LSCC by promoting β-Catenin degradation.

LOX-1 Activation by oxLDL Induces AR and AR-V7 Expression via NF-κB and STAT3 Signaling Pathways Reducing Enzalutamide Cytotoxic Effects.

The oxidized low-density lipoprotein receptor 1 (LOX-1) is one of the most important receptors for modified LDLs, such as oxidated (oxLDL) and acetylated (acLDL) low-density lipoprotein. LOX-1 and oxLDL are fundamental in atherosclerosis, where oxLDL/LOX1 promotes ROS generation and NF-κB activation inducing the expression of IL-6, a STAT3 activator. Furthermore, LOX-1/oxLDL function has been associated with other diseases, such as obesity, hypertension, and cancer. In prostate cancer (CaP), LOX-1 overexpression is associated with advanced stages, and its activation by oxLDL induces an epithelial-mesenchymal transition, increasing angiogenesis and proliferation. Interestingly, enzalutamide-resistant CaP cells increase the uptake of acLDL. Enzalutamide is an androgen receptor (AR) antagonist for castration-resistant prostate cancer (CRPC) treatment, and a high percentage of patients develop a resistance to this drug. The decreased cytotoxicity is promoted in part by STAT3 and NF-κB activation that induces the secretion of the pro-inflammatory program and the expression of AR and its splicing variant AR-V7. Here, we demonstrate for the first time that oxLDL/LOX-1 increases ROS levels and activates NF-κB, inducing IL-6 secretion and the activation of STAT3 in CRPC cells. Furthermore, oxLDL/LOX1 increases AR and AR-V7 expression and decreases enzalutamide cytotoxicity in CRPC. Thus, our investigation suggests that new factors associated with cardiovascular pathologies, such as LOX-1/oxLDL, may also promote important signaling axes for the progression of CRPC and its resistance to drugs used for its treatment.

FANCD2 inhibits ferroptosis by regulating the JAK2/STAT3 pathway in osteosarcoma

BackgroundThis research aimed to investigate the roles of fanconi anemia complementation group D2 (FANCD2) on the regulation of ferroptosis in osteosarcoma progression.MethodsThe function of FANCD2 on cell viability, invasion, migration, and tumor growth were explored. FANCD2 and pathway-related genes were determined by western blot. Ferroptosis-associated markers were determined, including lipid peroxidation, labile iron pool (LIP), ferrous iron (Fe2+), and ferroptosis-related genes.ResultsFANCD2 expression was increased in osteosarcoma cells. FANCD2 knockdown reduced cell viability, invasion, and migration of osteosarcoma cells. FANCD2 knockdown regulated ferroptosis-related gene expression, and distinctly increased the levels of LIP, Fe2+, and lipid peroxidation, and these effects were reversed by a ferroptosis inhibitor Fer-1. In addition, JAK2 and STAT3 expression were reduced by silencing of FANCD2, and STAT3 activator (colivelin) distinctly reversed tumor suppressor effects of FANCD2 silencing on osteosarcoma development.ConclusionThese findings suggested that FANCD2 silencing could suppress osteosarcoma cell viability, migration, invasion, and tumor growth, and induced ferroptosis by regulating the JAK2/STAT3 axis. These findings may provide novel therapeutic ideas for clinical treatment of osteosarcoma.

DOCK8 interference alleviates Aβ‑induced damage of BV2 cells by inhibiting STAT3/NLRP3/NF‑κB signaling.

Dementia is defined as memory loss and other cognitive decline and it severely influences daily life. Alzheimer's disease (AD) is the most common cause of dementia. Dedicator of cytokinesis 8 (DOCK8) is reported to be involved in neurological diseases. The present study focused on investigating the role that DOCK8 serves in AD and addressing its hidden regulatory mechanism. Initially, Aβ1-42 (Aβ) was applied for the administration of BV2 cells. Subsequently, the mRNA and protein expression levels of DOCK8 were evaluated utilizing reverse transcription-quantitative PCR (RT-qPCR) and western blotting. After the DOCK8 silencing, immunofluorescence staining (IF), ELISA, wound healing and Transwell assays were applied to assess ionized calcium binding adapter molecule-1 (IBA-1) expression, release of inflammatory factors, migration and invasion in Aβ-induced BV2 cells. IF was used to evaluate cluster of differentiation (CD)11b expression. RT-qPCR and western blotting were to analyze the levels of M1 cell markers inducible nitric oxide synthase (iNOS) and CD86. The expression of STAT3/NLR family pyrin domain containing 3 (NLRP3)/NF-κB signaling-related proteins were determined by western blotting. Finally, the viability and apoptosis in hippocampal HT22 cells with DOCK8 depletion were estimated. Results revealed that Aβ induction greatly stimulated the expression levels of IBA-1 and DOCK8. DOCK8 silencing suppressed Aβ-induced inflammation, migration and invasion of BV2 cells. Additionally, DOCK8 deficiency conspicuously decreased the expression levels of CD11b, iNOS and CD86. The expression of phosphorylated (p-)STAT3, NLRP3, ASC, caspase1 and p-p65 was downregulated in Aβ-induced BV2 cells after DOCK8 depletion. STAT3 activator Colivelin reversed the effects of DOCK8 knockdown on IBA-1 expression, inflammation, migration, invasion and M1 cell polarization. In addition, the viability and apoptosis in hippocampal HT22 cells stimulated by neuroinflammatory release of BV2 cells were repressed following DOCK8 deletion. Collectively, DOCK8 interference alleviated Aβ-induced damage of BV2 cells by inhibiting STAT3/NLRP3/NF-κB signaling.

STAT3 gene expression in ameloblastomas and odontogenic keratocysts

Introduction/Objective. STAT3 (signal transducers and activators of transcription) is involved in different physiological processes, including cell proliferation and survival. High expression of this protein is observed in various types of cancer. This study aimed to investigate the gene and protein expression of STAT3 in a series of odontogenic cysts and tumors to provide more information about their biological profile. Methods. The STAT3 gene expression at mRNA was quantified by real-time quantitative polymerase chain reaction (RT-qPCR) in 23 odontogenic keratocysts (OKCs) and seven ameloblastomas (AMs), and compared to the non-neoplastic oral mucosa. We also assessed the expression of STAT3 gene at protein levels, using immunohistochemistry, in 43 OKCs and 47 AMs. Results. STAT3 transcripts were found in 96.6% of the tumors studied; however, the gene was downregulated in OKC and AM compared to the non-neoplastic oral mucosa. The STAT3 gene expression at mRNA level was higher in sporadic OKC than in syndromic OKC (p = 0.04). There was no difference in STAT3 gene expression at mRNA level between OKCs and AMs (p = 0.88). Immunostaining of STAT3 revealed no significant difference between sporadic and syndrome OKC (p &gt; 0.05), nor between conventional and unicystic AMs (p &gt; 0.05). Ameloblastomas exhibited significantly higher STAT3 immunostaining than OKCs (p = 0.03). In OKC and AM, STAT3 immunostaining was predominantly cytoplasmic and no difference in the cellular localization of STAT3 was observed between these lesions (p = 0.58). Conclusion. Our findings showed low expression of STAT3 gene in OKCs and AMs in relation to nonneoplastic oral mucosa. However, higher STAT3 immunostaining was observed in AMs compared to OKCs.

Pathogenesis of Human Immunodeficiency Virus and Mycobacterium tuberculosis Infection as Revealed by Transcriptome and Interactome Data.

Tuberculosis (TB) among patients with human immunodeficiency virus (HIV) is a major global health burden and contributes to a high mortality rate due to HIV-mediated immunosuppression and subsequent susceptibility to TB. It is imperative to understand the pathogenesis of the association between HIV and TB for therapeutic innovation and preventive medicine. In the present study, we employed transcriptomic and bioinformatic analyses of differential gene expression data obtained from Gene Expression Omnibus (GEO) of the National Center for Biotechnology Information. The expression data of Mycobacterium tuberculosis-infected macrophages and blood samples from TB patients (GSE54992, GSE52819, and GSE19435) and blood samples from HIV patients (GSE30310) were accessed for identification of differentially expressed genes (DEGs). Data from 20 healthy subjects and 19 patients with TB and 16 healthy subjects and 16 patients with HIV were analyzed. We report here the DEGs shared by HIV and TB infection. Moreover, HIV and TB host-pathogen interaction data were collected from BIOGRID, v 4.4.210, for identifying significantly modulated genes' targets and their interactions with the host. Host targets, including PLSCR1 (phospholipid scramblase 1), STAT1 (signal transducer and activator of transcription-1 alpha/beta), FBXO6 (F-box only protein 6), ITGAL (integrin alpha-L), and APP (amyloid beta precursor protein), are commonly modulated in both diseases. The function of these targets was screened from and reconciled with the literature to understand their role in the pathogenesis of HIV and TB. Overall, the study results suggest that these targets may potentially be important contributors to the pathogenesis of this comorbidity. Further experimental work is needed for evaluating these new observations, with a view to future therapeutic innovation for patients with HIV and TB.

STAT3 signaling induced by the IL-6 family of cytokines modulates angiogenesis.

Aberrant angiogenesis is a hallmark of cardiovascular and retinal neovascular disease. The STAT3 signaling pathway represents a potential pharmacological target for these diseases due to its impact on angiogenesis. Surprisingly, some STAT3 activators, such as the IL-6 cytokine family member oncostatin M (OSM), enhance angiogenesis, whereas others, such as ciliary neurotropic factor (CNTF), reduce it. This study aimed to clarify these conflicting effects. In contrast to the anti-angiogenic cytokine CNTF, the pro-angiogenic cytokine OSM was able to activate intracellular signaling pathways beyond the STAT3 pathway, including the ERK and AKT pathways. These differences translated into transcriptomic and metabolic shifts. siRNA-mediated STAT3 knockdown experiments showed a decrease in VEGF-induced endothelial migration and sprouting, enhancing the pro-angiogenic drive of OSM and switching the CNTF response from anti-angiogenic to pro-angiogenic. These effects correlated with a transcriptomic shift representing enhanced STAT1 and ERK activity following STAT3 knockdown, including a compensatory prolonged phosphorylated STAT1 activity. In conclusion, the angiogenic effect of STAT3 appears to be determined by cytokine-induced STAT3 specificity and simultaneous activity of other intracellular signaling pathways, whereas the STAT3 pathway, predominantly recognized for its pro-angiogenic phenotypes, reveals novel anti-angiogenic potential.

Xuanfei Baidu Decoction suppresses complement overactivation and ameliorates IgG immune complex-induced acute lung injury by inhibiting JAK2/STAT3/SOCS3 and NF-κB signaling pathway

BackgroundThe significant clinical efficacy of Xuanfei Baidu Decoction (XFBD) is proven in the treatment of patients with coronavirus disease 2019 (COVID-19) in China. However, the mechanisms of XFBD against acute lung injury (ALI) are still poorly understood. MethodsIn vivo, the mouse model of ALI was induced by IgG immune complexes (IgG-IC), and then XFBD (4g/kg, 8g/kg) were administered by gavage respectively. 24 h after inducing ALI, the lungs were collected for histological and molecular analysis. In vitro, alveolar macrophages inflammation models induced by IgG-IC were performed and treated with different dosage of XFBD-containing serum to investigate the protective role and molecular mechanisms of XFBD. ResultsThe results revealed that XFBD mitigated lung injury and significantly downregulated the production of pro-inflammatory mediators in lung tissues and macrophages upon IgG-IC stimulation. Notably, XFBD attenuated C3a and C5a generation, inhibited the expression of C3aR and C5aR and suppressed the activation of JAK2/STAT3/SOCS3 and NF-κB signaling pathway in lung tissues and macrophages induced by IgG-IC. Moreover, in vitro experiments, we verified that Colivelin TFA (CAF, STAT3 activator) and C5a treatment markedly elevated the IgG-IC-triggered inflammatory responses in macrophages and XFBD weakened the effects of CAF or C5a. ConclusionXFBD suppressed complement overactivation and ameliorated IgG immune complex-induced acute lung injury by inhibiting JAK2/STAT3/SOCS3 and NF-κB signaling pathway. These data contribute to understanding the mechanisms of XFBD in COVID-19 treatment.

Fraxetin suppresses the proliferation, migration, and invasion of ovarian cancer cells by inhibiting the TLR4/STAT3 signaling pathway

Background Little therapeutic effect can be exerted on malignant ovarian cancer at the terminal period. Traditional Chinese medicine (TCM) has been a potential way for the treatment of various diseases. In this research, we probed into the potential curative effect of Fraxetin (FXT), a TCM monomer, on ovarian cancer. Methods Ovarian cancer cells were treated with FXT at different concentrations for 12 h, or pretreated by 0.5 μM of colivelin, a STAT3 activator, for 1 h and then treated with 80 μM of FXT for 12 h. The viability of ovarian cancer cells was measured by MTT assay, and the cell colony number was counted after colony formation assay. Transwell assay was conducted for investigating the relationship between the FXT at different concentrations and the invasion as well as migration rates of ovarian cancer cells. The expressions of epithelial-to-mesenchymal transition (EMT)-associated markers and TLR4/STAT3 signaling pathway-related proteins in ovarian cancer cells after the treatment of FXT were measured by western blot. Results FXT inhibited the viability, invasion, migration, and proliferation of SKOV3 and SW626 cells and suppressed EMT, but colivelin reversed the impacts of FXT. FXT also suppressed the expressions of N-cadherin, snail, vimentin, TLR4, phosphorylated (P)-STAT3, cyclin D1, and C-myc, whilst promoting that of E-cadherin by inhibiting the activation of TLR4/STAT3 signaling pathway. Conclusion FXT exerts a therapeutic effect on ovarian cancer by repressing the TLR4/STAT3 signaling pathway. With the accumulating concentrations of FXT, the therapeutic effect becomes more and more obvious.

A CAF-Fueled TIMP-1/CD63/ITGB1/STAT3 Feedback Loop Promotes Migration and Growth of Breast Cancer Cells.

Simple SummaryCarcinoma-associated fibroblasts (CAFs) are a major cellular component of the tumor microenvironment and influence cancer cell behavior in numerous ways. A large part of their actions is based on their high secretory activity, leading to the exposure of cancer cells to all kinds of bioactive factors, such as interleukin-6 (IL-6). Here, we present data showing that CAF-derived TIMP-1 activates STAT3 in breast cancer cells in cooperation with CD63 and integrin β1. In turn, STAT3 increases TIMP-1 secretion by breast cancer cells, leading to a TIMP-1/CD63/integrin β1/STAT3 positive feedback loop, which can be further fueled by IL-6. Functionally, this feedback loop is important for the CAF-induced increase in migratory activity and for CAF-induced resistance to the anti-estrogen fulvestrant.TIMP-1 is one of the many factors that CAFs have been shown to secret. TIMP-1 can act in a tumor-supportive or tumor-suppressive manner. The purpose of this study was to elucidate the role of CAF-secreted TIMP-1 for the effects of CAFs on breast cancer cell behavior. Breast cancer cells were exposed to conditioned medium collected from TIMP-1-secreting CAFs (CAF-CM), and the specific effects of TIMP-1 on protein expression, migration and growth were examined using TIMP-1-specifc siRNA (siTIMP1), recombinant TIMP-1 protein (rhTIMP-1) and TIMP-1 level-rising phorbol ester. We observed that TIMP-1 increased the expression of its binding partner CD63 and induced STAT3 and ERK1/2 activation by cooperating with CD63 and integrin β1. Since TIMP-1 expression was found to be dependent on STAT3, TIMP-1 activated its own expression, resulting in a TIMP-1/CD63/integrin β1/STAT3 feedback loop. IL-6, a classical STAT3 activator, further fueled this loop. Knock-down of each component of the feedback loop prevented the CAF-induced increase in migratory activity and inhibited cellular growth in adherent cultures in the presence and absence of the anti-estrogen fulvestrant. These data show that TIMP-1/CD63/integrin β1/STAT3 plays a role in the effects of CAFs on breast cancer cell behavior.

Notch1 Induces Defective Epithelial Surfactant Processing and Pulmonary Fibrosis.

Rationale: Although type II alveolar epithelial cells (AEC2s) are chronically injured in idiopathic pulmonary fibrosis (IPF), they contribute to epithelial regeneration in IPF. Objectives: We hypothesized that Notch signaling may contribute to AEC2 proliferation, dedifferentiation characterized by loss of surfactant processing machinery, and lung fibrosis in IPF. Methods: We applied microarray analysis, kinome profiling, flow cytometry, immunofluorescence analysis, western blotting, quantitative PCR, and proliferation and surface activity analysis to study epithelial differentiation, proliferation, and matrix deposition invitro (AEC2 lines, primary murine/human AEC2s), ex vivo (human IPF-derived precision-cut lung slices), and invivo (bleomycin and pepstatin application, Notch1 [Notch receptor 1] intracellular domain overexpression). Measurements and Main Results: We document here extensive SP-B and -C (surfactant protein-B and -C) processing defects in IPF AEC2s, due to loss of Napsin A, resulting in increased intra-alveolar surface tension and alveolar collapse and induction of endoplasmic reticulum stress in AEC2s. In vivo pharmacological inhibition of Napsin A results in the development of AEC2 injury and overt lung fibrosis. We also demonstrate that Notch1 signaling is already activated early in IPF and determines AEC2 fate by inhibiting differentiation (reduced lamellar body compartment, reduced capacity to process hydrophobic SP) and by causing increased epithelial proliferation and development of lung fibrosis, putatively via altered JAK (Janus kinase)/Stat (signal transducer and activator of transcription) signaling in AEC2s. Conversely, inhibition of Notch signaling in IPF-derived precision-cut lung slices improved the surfactant processing capacity of AEC2s and reversed fibrosis. Conclusions: Notch1 is a central regulator of AEC2 fate in IPF. It induces alveolar epithelial proliferation and loss of Napsin A and of surfactant proprotein processing, and it contributes to fibroproliferation.

Effect of Antioxidants on the Production of MCP-1 Chemokine by EA.hy926 Cells in Response to IL-6.

An elevated level of circulatory interleukin 6 (IL-6) is a biomarker for cytokine storm of various etiologies, including COVID-19, and contributes to poor prognosis. Vascular endothelial cells are one of the main targets of pathological action of IL-6. IL-6 activates the trans-signaling pathway via the formation of the IL-6/sIL-6Ra/gp130 receptor complex and subsequent activation of the JAK/STAT3 signaling pathway and PI3K/AKT and MEK/ERK kinases in some cases. Previously, it was shown by the authors' group and other researchers that reactive oxygen species (ROS), including mitochondrial ROS (mito-ROS), contribute to the induction of IL-6 expression in the endothelium, mainly due to increased activation of the transcription factor NF-kB. We have also shown that the mitochondria-targeted antioxidant SkQ1 (Plastoquinolyl-10(6'-decyltriphenyl)phosphonium) prevented tumor necrosis factor (TNF)-induced cytokine storm and death in mice. In the aortas of these animals, SkQ1 also prevented the increase in the expression of NF-kB-dependent genes, including the cytokine IL-6 and the chemokine MCP-1. In the current work, the hypothesis of mito-ROS involvement in the IL-6-signaling-mediated proinflammatory gene expression in endothelial cells is tested. SkQ1 suppressed the expression and secretion of the MCP-1 chemokine, induced by IL-6 in combination with sIL-6-Ra, but not the expression of ICAM-1 adhesion molecules in EA.hy926 human endothelial cells. Using specific inhibitors, the authors have shown that, in EA.hy926 cells, IL-6-induced expression of MCP-1 and ICAM-1 depends on the signaling protein and transcription activator STAT3 and, in some cases, on JNK, PI3K, and MEK1/2 kinases and is independent of p38 kinase. In this model, IL-6 induced rapid STAT3 activation, while ERK1/2 activation was less pronounced, and there was no IL-6 effect on Akt and JNK activation. SkQ1 partially suppressed STAT3 and ERK1/2 activation. Thus, we have shown that SkQ1 suppresses not only NF-kB-dependent expression of IL-6 and other proinflammatory genes but also IL-6-induced activation of JAK/STAT3 and STAT3-dependent expression of MCP-1, which probably contributes to the overall therapeutic effect of SkQ1.