Minocycline blocks asthma-associated inflammation in part by interfering with the T cell receptor-nuclear factor κB-GATA-3-IL-4 axis without a prominent effect on poly(ADP-ribose) polymerase

Unconventional activation of PRKDC by TNF-α: deciphering its crucial role in Th1-mediated inflammation beyond DNA repair as part of the DNA-PK complex

BACKGROUND

The DNA-dependent protein kinase (DNA-PK) complex comprises a catalytic (PRKDC) and two requisite DNA-binding (Ku70/Ku80) subunits. The role of the complex in repairing double-stranded DNA breaks (DSBs) is established, but its role in inflammation, as a complex or individual subunits, remains elusive. While only ~ 1% of PRKDC is necessary for DNA repair, we reported that partial inhibition blocks asthma in mice without causing SCID.

METHODS

We investigated the central role of PRKDC in inflammation and its potential association with DNA repair. We also elucidated the relationship between inflammatory cytokines (e.g., TNF-α) and PRKDC by analyzing its connections to inflammatory kinases. Human cell lines, primary human endothelial cells, and mouse fibroblasts were used to conduct the in vitro studies. For animal studies, LPS- and oxazolone-induced mouse models of acute lung injury (ALI) and delayed-type hypersensitivity (DHT) were used. Wild-type, PRKDC+/-, or Ku70+/- mice used in this study.

RESULTS

A ~ 50% reduction in PRKDC markedly blocked TNF-α-induced expression of inflammatory factors (e.g., ICAM-1/VCAM-1). PRKDC regulates Th1-mediated inflammation, such as DHT and ALI, and its role is highly sensitive to inhibition achieved by gene heterozygosity or pharmacologically. In endothelial or epithelial cells, TNF-α promoted rapid PRKDC phosphorylation in a fashion resembling that induced by, but independent of, DSBs. Ku70 heterozygosity exerted little to no effect on ALI in mice, and whatever effect it had was associated with a specific increase in MCP-1 in the lungs and systemically. While Ku70 knockout blocked VP-16-induced PRKDC phosphorylation, it did not prevent TNF-α - induced phosphorylation of the kinase, suggesting Ku70 dispensability. Immunoprecipitation studies revealed that PRKDC transiently interacts with p38MAPK. Inhibition of p38MAPK blocked TNF-α-induced PRKDC phosphorylation. Direct phosphorylation of PRKDC by p38MAPK was demonstrated using a cell-free system.

CONCLUSIONS

This study presents compelling evidence that PRKDC functions independently of the DNA-PK complex, emphasizing its central role in Th1-mediated inflammation. The distinct functionality of PRKDC as an individual enzyme, its remarkable sensitivity to inhibition, and its phosphorylation by p38MAPK offer promising therapeutic opportunities to mitigate inflammation while sparing DNA repair processes. These findings expand our understanding of PRKDC biology and open new avenues for targeted anti-inflammatory interventions.

Minocycline and antipsychotics inhibit inflammatory responses in BV-2 microglia activated by LPS via regulating the MAPKs/ JAK-STAT signaling pathway

BACKGROUND

Abnormal activation of microglia is involved in the pathogenesis of schizophrenia. Minocycline and antipsychotics have been reported to be effective in inhibiting the activation of microglia and thus alleviating the negative symptoms of patients with schizophrenia. However, the specific molecular mechanism by which minocycline and antipsychotics inhibit microglial activation is not clear. In this study, we aimed to explore the molecular mechanism of treatment effect of minocycline and antipsychotics on schizophrenia.

METHODS

Microglia cells were activated by lipopolysaccharide (LPS) and further treated with minocycline, haloperidol, and risperidone. Then cell morphology, specific marker, cytokines, and nitric oxide production process, and the proteins in related molecular signaling pathways in LPS-activated microglia were compared among groups.

RESULTS

The study found that minocycline, risperidone, and haloperidol significantly inhibited morphological changes and reduced the expression of OX-42 protein induced by LPS. Minocycline significantly decreased the production of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β). Risperidone also showed significant decrease in the production of IL-6 and TNF-α, while haloperidol only showed significant decrease in the production of IL-6. Minocycline, risperidone, and haloperidol were found to significantly inhibit nitric oxide (NO) expression, but had no effect on inducible nitric oxide synthase (iNOS) expression. Both minocycline and risperidone were effective in decreasing the activity of c‑Jun N‑terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in the mitogen-activated protein kinases (MAPKs) signal pathway. Additionally, minocycline and risperidone were found to increase the activity of phosphorylated-p38. In contrast, haloperidol only suppressed the activity of ERK. Minocycline also suppressed the activation of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), while risperidone and haloperidol only suppressed the activation of STAT3.

CONCLUSIONS

The results demonstrated that minocycline and risperidone exert stronger anti-inflammatory and neuroprotective effects stronger than haloperidol, through MAPKs and Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathways in BV2 cells stimulated with LPS, revealing the underlying mechanisms of minocycline and atypical antipsychotics in the treatment of negative schizophrenia symptoms.

The anti-inflammatory effects of minocycline on lipopolysaccharide-induced paw oedema in rats: a histopathological and molecular study

Minocycline is a semi-synthetic antimicrobial agent with claimed anti-inflammatory properties reported from different experimental models. This study was aimed to evaluate the anti-inflammatory effects of minocycline, compared to the actions of two common anti-inflammatory agents, on lipopolysaccharide (LPS)-induced paw oedema through some clinical, histopathological, haematological and molecular analyses. Forty-eight rats were divided into eight groups (n = 6). In control group (Ctrl), each animal was injected with normal saline into its sub-plantar region of hind paw. In groups 2-7, hind paw oedema was induced by injection of LPS. One hour before injections, groups 1 (Ctrl) and 2 (LPS) were treated orally with distilled water, 3 and 4 with methylprednisolone (Pred) and meloxicam (Melo) and 5-7 with minocycline in doses of 50, 150 and 450 mg/kg (M50, M150 and M450, respectively). The 8th group (MC) was given minocycline (150 mg/kg) orally and normal saline was injected into sub-plantar region. Paw swelling and body temperature were assessed at 0, 2, 4, 6 and 24 h post-injections. At 24 h, samples of blood and liver, kidney, spleen and hind paw tissues were taken for haematological and histopathological examinations. Some samples of the paw were also obtained for molecular analysis of some inflammatory-related cytokines at mRNA level. Paw swelling and body temperature increased in all LPS-injected groups 2 h post-injection. In LPS group, they remained significantly increased up to 24 h; however, these parameters decreased to normal in Pred, Melo and all minocycline groups. The histological findings showed mild-to-moderate signs of inflammation in tissue samples of groups 2-6, but not in group M450. Additionally, gene expression of pro-inflammatory cytokines (IL-1β and IL-6) increased significantly in LPS group compared to other groups. In conclusion, this study supports the role of minocycline as an anti-inflammatory agent with effects comparable to those of meloxicam and methylprednisolone.

An exopolysaccharide from Bacillus subtilis alleviates airway inflammatory responses via the NF-κB and STAT6 pathways in asthmatic mice

Bacillus subtilis is an intestinal probiotic for immune homeostasis and its exopolysaccharide (EPS) is known to possess anti-inflammatory and antioxidant properties. The underlying mechanisms are not yet fully understood. In the present study, we investigated the effects of the EPS (50, 100, 200 mg/kg) on airway inflammation in asthmatic mice. Our results showed that EPS treatment of asthmatic mice significantly alleviated pathological damage in the lungs, remarkably decreased the counts of total inflammatory cells including lymphocytes, and eosinophils in the bronchoalveolar lavage fluid (BALF) and reduced indexes of oxidative damage. Moreover, the expression of type II T-helper cell (Th2) cytokines (interleukin- (IL)4 and -5) subsequent to EPS treatment was found to be dramatically down-regulated in a concentration-dependent manner. Additionally, the EPS treatment reduced JAK1, STAT6 and nuclear factor-κB (NF-κB) expression in the lungs of asthmatic mice. Taken together, these results suggest that the EPS from B. subtilis alleviates asthmatic airway inflammation, which involves the reduction in reactive oxygen species (ROS) and the down-regulation of the STAT6 and NF-κB inflammatory pathways, which can further reduce Th2 cytokine expression and eosinophilic inflammation. Thus, our findings provide a potential mechanism through which the EPS mitigates asthma, suggesting that the EPS could be a potential source of an anti-asthmatic drug.

Blockade of GITRL/GITR signaling pathway attenuates house dust mite-induced allergic asthma in mice through inhibition of MAPKs and NF-κB signaling

GITRL/GITR signaling pathway plays an important role in allergy, inflammation, transplantation and autoimmunity. However, its role in asthma remains unclear. Thus, the present study aimed to investigate changes in this pathway and observe the therapeutic effect of its blocking on asthma. By using house dust mite-induced asthma model, changes of GITRL/GITR and its downstream molecules MAPKs (e.g., p38 MAPK, JNK and Erk) and NF-κB were observed. After that, GITRL in lung of mice was knocked down by recombinant adeno-associated virus to observe the impact on its downstream molecules and assess the therapeutic effect on asthma. These results showed that GITRL/GITR and its downstream molecules MAPKs/NF-κB were activated in asthmatic mice. This activation was suppressed after GITRL knockdown, and allergic airway inflammation and airway hyperresponsiveness were alleviated. These results demonstrate that GITRL/GITR-MAPKs/NF-κB signaling pathway participates in the pathogenesis of asthma. Blockade of GITRL/GITR signaling pathway exhibits protective effects in a mouse model of house dust mite-induced allergic asthma.

GITRL on dendritic cells aggravates house dust mite-induced airway inflammation and airway hyperresponsiveness by modulating CD4+ T cell differentiation

Background

Glucocorticoid-induced tumor necrosis factor receptor family-related protein ligand (GITRL) plays an important role in tumors, autoimmunity and inflammation. However, GITRL is not known to modulate the pathogenesis of allergic asthma. In this study, we investigated whether regulating GITRL expressed on dendritic cells (DCs) can prevent asthma and to elucidate its mechanism of action.

Methods

In vivo, the role of GITRL in modulating house dust mite (HDM)-induced asthma was assessed in adeno-associated virus (AAV)-shGITRL mice. In vitro, the role of GITRL expression by DCs was evaluated in LV-shGITRL bone marrow dendritic cells (BMDCs) under HDM stimulation. And the direct effect of GITRL was observed by stimulating splenocytes with GITRL protein. The effect of regulating GITRL on CD4⁺ T cell differentiation was detected. Further, GITRL mRNA in the peripheral blood of asthmatic children was tested.

Results

GITRL was significantly increased in HDM-challenged mice. In GITRL knockdown mice, allergen-induced airway inflammation, serum total IgE levels and airway hyperresponsiveness (AHR) were reduced. In vitro, GITRL expression on BMDCs was increased after HDM stimulation. Further, knocking down GITRL on DCs partially restored the balance of Th1/Th2 and Th17/Treg cells. Moreover, GITRL stimulation in vitro inhibited Treg cell differentiation and promoted Th2 and Th17 cell differentiation. Similarly, GITRL mRNA expression was increased in the peripheral blood from asthmatic children.

Conclusions

This study identified a novel role for GITRL expressed by DCs as a positive regulator of CD4⁺ T cells responses in asthma, which implicates that GITRL inhibitors may be a potential immunotherapy for asthma.

Minocycline impairs TNF-α-induced cell fusion of M13SV1-Cre cells with MDA-MB-435-pFDR1 cells by suppressing NF-κB transcriptional activity and its induction of target-gene expression of fusion-relevant factors

Background

To date, several studies have confirmed that driving forces of the inflammatory tumour microenvironment trigger spontaneous cancer cell fusion. However, less is known about the underlying factors and mechanisms that facilitate inflammation-induced cell fusion of a cancer cell with a normal cell. Recently, we demonstrated that minocycline, a tetracycline antibiotic, successfully inhibited the TNF-α-induced fusion of MDA-MB-435 cancer cells with M13SV1 breast epithelial cells. Here, we investigated how minocycline interferes with the TNF-α induced signal transduction pathway.

Methods

A Cre-LoxP recombination system was used to quantify the fusion of MDA-MB-435-pFDR1 cancer cells and M13SV1-Cre breast epithelial cells. The impact of minocycline on the TNF-α signalling pathway was determined by western blotting. The transcriptional activity of NF-κB was characterised by immunocytochemistry, western blot and ChIP analyses. An NF-κB-luciferase reporter assay was indicative of NF-κB activity.

Results

Minocycline treatment successfully inhibited the TNFR1-TRAF2 interaction in both cell types, while minocycline abrogated the phosphorylation of IκBα and NF-κB-p65 to suppress nuclear NF-κB and its promotor activity only in M13SV1-Cre cells, which attenuated the expression of MMP9 and ICAM1. In MDA-MB-435-pFDR1 cells, minocycline increased the activity of NF-κB, leading to greater nuclear accumulation of NF-κB-p65, thus increasing promoter activity to stimulate the expression of ICAM1. Even though TNF-α also activated all MAPKs (ERK1/2, p38 and JNK), minocycline differentially affected these kinases to either inhibit or stimulate their activation. Moreover, SRC activation was analysed as an upstream activator of MAPKs, but no activation by TNF-α was revealed. The addition of several specific inhibitors that block the activation of SRC, MAPKs, AP-1 and NF-κB confirmed that only NF-κB inhibition was successful in inhibiting the TNF-α-induced cell fusion process.

Conclusion

Minocycline is a potent inhibitor in the TNF-α-induced cell fusion process by targeting the NF-κB pathway. Thus, minocycline prevented NF-κB activation and nuclear translocation to abolish the target-gene expression of MMP9 and ICAM1 in M13SV1-Cre cells, resulting in reduced cell fusion frequency.

Research Progress on PARP14 as a Drug Target

Poly-adenosine diphosphate-ribose polymerase (PARP) implements posttranslational mono- or poly-ADP-ribosylation modification of target proteins. Among the known 18 members in the enormous family of PARP enzymes, several investigations about PARP1, PARP2, and PARP5a/5b have been launched in the past few decades; more specifically, PARP14 is gradually emerging as a promising drug target. An intact PARP14 (also named ARTD8 or BAL2) is constructed by macro1, macro2, macro3, WWE, and the catalytic domain. PARP14 takes advantage of nicotinamide adenine dinucleotide (NAD⁺) as a metabolic substrate to conduct mono-ADP-ribosylation modification on target proteins, taking part in cellular responses and signaling pathways in the immune system. Therefore, PARP14 has been considered a fascinating target for treatment of tumors and allergic inflammation. More importantly, PARP14 could be a potential target for a chemosensitizer based on the theory of synthetic lethality and its unique role in homologous recombination DNA repair. This review first gives a brief introduction on several representative PARP members. Subsequently, current literatures are presented to reveal the molecular mechanisms of PARP14 as a novel drug target for cancers (e.g., diffuse large B-cell lymphoma, multiple myeloma, prostate cancer, and hepatocellular carcinoma) and allergic inflammatory. Finally, potential PARP inhibitor-associated adverse effects are discussed. The review could be a meaningful reference for innovative drug or chemosensitizer discovery targeting to PARP14.

Mast cells partially contribute to mucosal adjuvanticity of surfactin in mice

Introduction

Surfactin (SF) is a cyclic lipopeptide that has potent mucosal adjuvant properties. However, immunological mechanisms of SF adjuvant action have not yet been elucidated. As some cyclic lipopeptides, such as polymyxin, can stimulate histamine release from mast cells, we hypothesized that mast cell activation is critical for SF adjuvanticity.

Methods/Results

We observed that following intranasal immunization with ovalbumin (OVA) plus SF, the titers of the OVA‐specific antibody (Ab) in the mucosal secretions and plasma of mast cell‐deficient mice were significantly lower than those in congenic normal mice, although OVA‐specific Ab did not entirely disappear from mast cell‐deficient mice. SF induced degranulation of mast cells and release of histamine in vitro. To investigate whether SF stimulated mast cells in vivo, we measured body temperature of mice immunized intranasally with OVA plus SF because histamine level affects body temperature. Following immunizations, body temperature of immunized congenic normal mice transiently decreased, whereas body temperature of mast cell‐deficient mice did not change. Plasma levels of OVA‐specific IgE Ab were not significantly different in mast cell‐deficient and congenic normal mice. These findings suggest that SF directly affected mast cells in an IgE Ab‐independent fashion. Furthermore, we analyzed the effects of SF on MC/9 mast cells cultured in vitro. MC/9 cells stimulated by SF released not only histamine but also leukotriene B₄ and prostaglandin D₂. Moreover, SF up‐regulated mRNA expression levels of Tnf, Ccr5, and Il4 genes in mast cells. These cytokines may play a facilitating role in OVA‐specific immune responses in mice.

Conclusion

Overall, our results showed that mast cell activation partially mediated SF adjuvanticity.

Fuelling the mechanisms of asthma: Increased fatty acid oxidation in inflammatory immune cells may represent a novel therapeutic target

BACKGROUND

Increasing evidence has shown the close link between energy metabolism and the differentiation, function, and longevity of immune cells. Chronic inflammatory conditions such as parasitic infections and cancer trigger a metabolic reprogramming from the preferential use of glucose to the up-regulation of fatty acid oxidation (FAO) in myeloid cells, including macrophages and granulocytic and monocytic myeloid-derived suppressor cells. Asthma is a chronic inflammatory condition where macrophages, eosinophils, and polymorphonuclear cells play an important role in its pathophysiology.

OBJECTIVE

We tested whether FAO might play a role in the development of asthma-like traits and whether the inhibition of this metabolic pathway could represent a novel therapeutic approach.

METHODS

OVA- and house dust mite (HDM)-induced murine asthma models were used in this study.

RESULTS

Key FAO enzymes were significantly increased in the bronchial epithelium and inflammatory immune cells infiltrating the respiratory epithelium of mice exposed to OVA or HDM. Pharmacologic inhibition of FAO significantly decreased allergen-induced airway hyperresponsiveness, decreased the number of inflammatory cells, and reduced the production of cytokines and chemokines associated with asthma.

CONCLUSIONS AND CLINICAL RELEVANCE

These novel observations suggest that allergic airway inflammation increases FAO in inflammatory cells to support the production of cytokines, chemokines, and other factors important in the development of asthma. Inhibition of FAO by re-purposing existing drugs approved for the treatment of heart disease may provide a novel therapeutic approach for the treatment of asthma.

A pilot, open-label, 8-week study evaluating the efficacy, safety and tolerability of adjunctive minocycline for the treatment of bipolar I/II depression

OBJECTIVES

The objectives of the study were to determine if adjunctive minocycline mitigates depressive symptom severity and improves cognitive function in individuals with bipolar I/II disorder (BD). The study also aimed to determine if changes in depressive and/or cognitive symptoms over the course of treatment were associated with changes in circulating inflammatory cytokine levels.

METHODS

A total of 29 (intention-to-treat: n=27) adults meeting DSM-IV-TR criteria for a major depressive episode as part of bipolar I or II disorder (i.e. Hamilton Depression Rating Scale 17-item [HAMD-17] ≥20) were enrolled in an 8-week, open-label study with adjunctive minocycline (100 mg bid). The primary outcome measure was the Montgomery-Åsberg Depression Rating Scale (MADRS). The HAMD-17, Clinical Global Impression-Severity (CGI-S), cognitive test composite scores and plasma cytokines were secondary outcome measures. Plasma cytokines were measured with the 30 V-Plex Immunoassay from Meso Scale Discovery.

RESULTS

Adjunctive minocycline was associated with a reduction in depressive symptom severity from baseline to week 8 on the MADRS (P<.001, d=0.835), HAMD-17 (P<.001, d=0.949) and CGI-S (P<.001, d=1.09). Improvement in psychomotor speed, but not verbal memory or executive function, was observed only amongst individuals exhibiting a reduction in depression severity (P=.007, d=0.826). Levels of interleukin (IL)-12/23p40 (P=.002) were increased, while levels of IL-12p70 (P=.001) and C-C motif chemokine ligand 26 (CCL26) (P<.001) were reduced from baseline to week 8. A reduction in CCL26 levels was associated with a less favourable treatment response (P<.001).

CONCLUSIONS

Results from the pilot study suggest that adjunctive minocycline may exert antidepressant effects in individuals with bipolar depression, possibly by targeting inflammatory cytokines.

Opportunities for the repurposing of PARP inhibitors for the therapy of non-oncological diseases

The recent clinical availability of the PARP inhibitor olaparib (Lynparza) opens the door for potential therapeutic repurposing for non-oncological indications. Considering (a) the preclinical efficacy data with PARP inhibitors in non-oncological diseases and (b) the risk-benefit ratio of treating patients with a compound that inhibits an enzyme that has physiological roles in the regulation of DNA repair, we have selected indications, where (a) the severity of the disease is high, (b) the available therapeutic options are limited, and (c) the duration of PARP inhibitor administration could be short, to provide first-line options for therapeutic repurposing. These indications are as follows: acute ischaemic stroke; traumatic brain injury; septic shock; acute pancreatitis; and severe asthma and severe acute lung injury. In addition, chronic, devastating diseases, where alternative therapeutic options cannot halt disease development (e.g. Parkinson's disease, progressive multiple sclerosis or severe fibrotic diseases), should also be considered. We present a preclinical and clinical action plan for the repurposing of PARP inhibitors.

LINKED ARTICLES

This article is part of a themed section on Inventing New Therapies Without Reinventing the Wheel: The Power of Drug Repurposing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.2/issuetoc.

ApoE deficiency promotes colon inflammation and enhances inflammatory potential oxidized-LDL and TNF-α in colon epithelial cells

Although deficiency in Apolipoprotein E (ApoE) is linked to many diseases, its effect on colon homoeostasis remains unknown. ApoE appears to control inflammation by regulating nuclear factor-κB (NF-κB). The present study was designed to examine whether ApoE deficiency affects factors of colon integrity in vivo and given the likelihood that ApoE deficiency increases oxidized lipids and TNF-α, the present study also examined whether such deficiency enhances the inflammatory potential of oxidized-LDL (oxLDL) and TNF-α in colon epithelial cells (CECs), in vitro. Here we show that ApoE deficiency is associated with chronic inflammation systemically and in colonic tissues as assessed by TNF-α levels. Increased colon TNF-α mRNA coincided with a substantial increase in cyclooxygenase (COX)-2. ApoE deficiency enhanced the potential of oxLDL and TNF-α to induce COX-2 expression as well as several other inflammatory factors in primary CECs. Interestingly, oxLDL enhanced TGF-β expression only in ApoE^−/−, but not in wild-type, epithelial cells. ApoE deficiency appears to promote COX-2 expression enhancement through a mechanism that involves persistent NF-κB nuclear localization and PI3 and p38 MAP kinases but independently of Src. In mice, ApoE deficiency promoted a moderate increase in crypt length, which was associated with opposing effects of an increase in cell proliferation and apoptosis at the bottom and top of the crypt respectively. Our results support the notion that ApoE plays a central role in colon homoeostasis and that ApoE deficiency may constitute a risk factor for colon pathologies.

Target-Based Drug Repositioning Using Large-Scale Chemical-Protein Interactome Data

Drug repositioning, or the identification of new indications for known drugs, is a useful strategy for drug discovery. In this study, we developed novel computational methods to predict potential drug targets and new drug indications for systematic drug repositioning using large-scale chemical-protein interactome data. We explored the target space of drugs (including primary targets and off-targets) based on chemical structure similarity and phenotypic effect similarity by making optimal use of millions of compound-protein interactions. On the basis of the target profiles of drugs, we constructed statistical models to predict new drug indications for a wide range of diseases with various molecular features. The proposed method outperformed previous methods in terms of interpretability, applicability, and accuracy. Finally, we conducted a comprehensive prediction of the drug-target-disease association network for 8270 drugs and 1401 diseases and showed biologically meaningful examples of newly predicted drug targets and drug indications. The predictive model is useful to understand the mechanisms of the predicted drug indications.

Minocycline inhibits peritoneal macrophages but activates alveolar macrophages in acute pancreatitis

Minocycline is a tetracycline antibiotic that, in addition to its antimicrobial function, has been reported to possess a relevant anti-inflammatory activity. Its effects have been extensively evaluated in inflammatory-related neurological diseases. Here, we evaluate its effect on the systemic inflammatory response in a model of experimental acute pancreatitis. Minocycline treatment significantly reduced the inflammation in pancreas and mesenterium, had no effect on the adipose tissue inflammation, and increased the inflammatory response in the lung. These differences seem to be related with different effects exerted on peritoneal and alveolar macrophages. In vitro, minocycline reduced the expression of IL-1β and inhibit the activation of nuclear factor kappa B (NF-κB) on peritoneal macrophages, while it had no effect on alveolar macrophages. Our data indicates that although minocycline may be useful as a tool to control some inflammatory processes, differences on its effects depending on the population of macrophages involved in the process can be expected. In the particular case of acute pancreatitis, it could promote or potentiate inflammation in the lung so that its use does not appear to be recommended.

PARP is activated in human asthma and its inhibition by olaparib blocks house dust mite-induced disease in mice

The present study establishes poly(ADP-ribose)polymerase's (PARP's) role in chronic asthma, demonstrates that it is activated in human asthma, increases the clinical relevance of targeting PARP for blocking or preventing chronic asthma in humans and presents olaparib as a likely candidate drug.

Our laboratory established a role for poly(ADP-ribose)polymerase (PARP) in asthma. To increase the clinical significance of our studies, it is imperative to demonstrate that PARP is actually activated in human asthma, to examine whether a PARP inhibitor approved for human testing such as olaparib blocks already-established chronic asthma traits in response to house dust mite (HDM), a true human allergen, in mice and to examine whether the drug modulates human cluster of differentiation type 4 (CD4⁺) T-cell function. To conduct the study, human lung specimens and peripheral blood mononuclear cells (PBMCs) and a HDM-based mouse asthma model were used. Our results show that PARP is activated in PBMCs and lung tissues of asthmatics. PARP inhibition by olaparib or gene knockout blocked established asthma-like traits in mice chronically exposed to HDM including airway eosinophilia and hyper-responsiveness. These effects were linked to a marked reduction in T helper 2 (Th2) cytokine production without a prominent effect on interferon (IFN)-γ or interleukin (IL)-10. PARP inhibition prevented HDM-induced increase in overall cellularity, weight and CD4⁺ T-cell population in spleens of treated mice whereas it increased the T-regulatory cell population. In CD3/CD28-stimulated human CD4 ⁺T-cells, olaparib treatment reduced Th2 cytokine production potentially by modulating GATA binding protein-3 (gata-3)/IL-4 expression while moderately affecting T-cell proliferation. PARP inhibition inconsistently increased IL-17 in HDM-exposed mice and CD3/CD28-stimulated CD4⁺ T cells without a concomitant increase in factors that can be influenced by IL-17. In the present study, we provide evidence for the first time that PARP-1 is activated in human asthma and that its inhibition is effective in blocking established asthma in mice.

PARP inhibition by olaparib or gene knockout blocks asthma-like manifestation in mice by modulating CD4(+) T cell function

Background

An important portion of asthmatics do not respond to current therapies. Thus, the need for new therapeutic drugs is urgent. We have demonstrated a critical role for PARP in experimental asthma. Olaparib, a PARP inhibitor, was recently introduced in clinical trials against cancer. The objective of the present study was to examine the efficacy of olaparib in blocking established allergic airway inflammation and hyperresponsiveness similar to those observed in human asthma in animal models of the disease.

Methods

We used ovalbumin (OVA)-based mouse models of asthma and primary CD4⁺ T cells. C57BL/6J WT or PARP-1^−/− mice were subjected to OVA sensitization followed by a single or multiple challenges to aerosolized OVA or left unchallenged. WT mice were administered, i.p., 1 mg/kg, 5 or 10 mg/kg of olaparib or saline 30 min after each OVA challenge.

Results

Administration of olaparib in mice 30 min post-challenge promoted a robust reduction in airway eosinophilia, mucus production and hyperresponsiveness even after repeated challenges with ovalbumin. The protective effects of olaparib were linked to a suppression of Th2 cytokines eotaxin, IL-4, IL-5, IL-6, IL-13, and M-CSF, and ovalbumin-specific IgE with an increase in the Th1 cytokine IFN-γ. These traits were associated with a decrease in splenic CD4⁺ T cells and concomitant increase in T-regulatory cells. The aforementioned traits conferred by olaparib administration were consistent with those observed in OVA-challenged PARP-1^−/− mice. Adoptive transfer of Th2-skewed OT-II-WT CD4⁺ T cells reversed the Th2 cytokines IL-4, IL-5, and IL-10, the chemokine GM-CSF, the Th1 cytokines IL-2 and IFN-γ, and ovalbumin-specific IgE production in ovalbumin-challenged PARP-1^−/−mice suggesting a role for PARP-1 in CD4⁺ T but not B cells. In ex vivo studies, PARP inhibition by olaparib or PARP-1 gene knockout markedly reduced CD3/CD28-stimulated gata-3 and il4 expression in Th2-skewed CD4⁺ T cells while causing a moderate elevation in t-bet and ifn-γ expression in Th1-skewed CD4⁺ T cells.

Conclusions

Our findings show the potential of PARP inhibition as a viable therapeutic strategy and olaparib as a likely candidate to be tested in human asthma clinical trials.

Hierarchical control of coherent gene clusters defines the molecular mechanisms of glioblastoma

Glioblastoma is a highly-aggressive and rapidly-lethal tumor characterized by resistance to therapy. Although data on multiple genes, proteins, and pathways are available, the key challenge is deciphering this information and identifying central molecular targets. Therapeutically targeting individual molecules is often unsuccessful due to the presence of compensatory and redundant pathways, and crosstalk. A systems biology approach that involves a hierarchical gene group networks analysis can delineate the coherent functions of different disease mediators. Here, we report an integrative networks-based analysis to identify a system of coherent gene modules in primary and secondary glioblastoma. Our study revealed a hierarchical transcriptional control of genes in these modules. We elucidated those modules responsible for conversion of the glioma-associated microglia/macrophages into glioma-supportive, immunosuppressive cells. Further, we identified clusters comprising mediators of angiogenesis, proliferation, and cell death for both primary and secondary glioblastomas. Data obtained for these clusters point to a possible role of transcription regulators that function as the gene modules mediators in glioblastoma pathogenesis. We elucidated a set of possible transcription regulators that can be targeted to affect the selected gene clusters at specific levels for glioblastoma. Our innovative approach to construct informative disease models may hold the key to successful management of complex diseases including glioblastoma and other cancers.

DNA-dependent protein kinase inhibition blocks asthma in mice and modulates human endothelial and CD4⁺ T-cell function without causing severe combined immunodeficiency

BACKGROUND

We reported that DNA-dependent protein kinase (DNA-PK) is critical for the expression of nuclear factor κB-dependent genes in TNF-α-treated glioblastoma cells, suggesting an involvement in inflammatory diseases.

OBJECTIVE

We sought to investigate the role of DNA-PK in asthma.

METHODS

Cell culture and ovalbumin (OVA)- or house dust mite-based murine asthma models were used in this study.

RESULTS

DNA-PK was essential for monocyte adhesion to TNF-α-treated endothelial cells. Administration of the DNA-PK inhibitor NU7441 reduced airway eosinophilia, mucus hypersecretion, airway hyperresponsiveness, and OVA-specific IgE production in mice prechallenged with OVA. Such effects correlated with a marked reduction in lung vascular cell adhesion molecule 1 expression and production of several cytokines, including IL-4, IL-5, IL-13, eotaxin, IL-2, and IL-12 and the chemokines monocyte chemoattractant protein 1 and keratinocyte-derived chemokine, with a negligible effect on IL-10/IFN-γ production. DNA-PK inhibition by gene heterozygosity of the 450-kDa catalytic subunit of the kinase (DNA-PKcs(+/-)) also prevented manifestation of asthma-like traits. These results were confirmed in a chronic model of asthma by using house dust mite, a human allergen. Remarkably, such protection occurred without causing severe combined immunodeficiency. Adoptive transfer of TH2-skewed OT-II wild-type CD4(+) T cells reversed IgE and TH2 cytokine production but not airway hyperresponsiveness in OVA-challenged DNA-PKcs(+/-) mice. DNA-PK inhibition reduced IL-4, IL-5, IL-13, eotaxin, IL-8, and monocyte chemoattractant protein 1 production without affecting IL-2, IL-12, IFN-γ, and interferon-inducible protein 10 production in CD3/CD28-stimulated human CD4(+) T cells, potentially by blocking expression of Gata3. These effects occurred without significant reductions in T-cell proliferation. In mouse CD4(+) T cells in vitro DNA-PK inhibition severely blocked CD3/CD28-induced Gata3 and T-bet expression in CD4(+) T cells and prevented differentiation of TH1 and TH2 cells under respective TH1- and TH2-skewing conditions.

CONCLUSION

Our results suggest DNA-PK as a novel determinant of asthma and a potential target for the treatment of the disease.

Protective effects of astragaloside IV against ovalbumin-induced lung inflammation are regulated/mediated by T-bet/GATA-3

Bronchial asthma is characterized by chronic lung inflammation, airway hyperresponsiveness, and airway remodelling. Astragaloside IV (3-O-β-D-xylopyranosyl-6-O-β-D-glucopyranosyl-cycloastragenol, AST), the primary pure saponin isolated from the root of Astragalus membranaceus, is an effective compound with distinct pharmacological effects including anti-inflammation, immunoregulation, and antifibrosis. However, the effect of AST on asthma remains unclear. In the present study, in the murine model of asthma, the airway hyperresponsiveness was relieved after treatment with AST, accompanied by a reduction of inflammatory cells. In addition, the levels of IL-4 and IL-5 decreased, while the IFN-γ level increased, in bronchoalveolar lavage fluid. The compound also significantly inhibited the synthesis of GATA-3-encoding mRNA and protein in addition to increasing the synthesis of T-bet-encoding mRNA and protein in both lung tissues and CD4+ T cells. Our findings indicate that AST treatment inhibits ovalbumin-induced airway inflammation by modulating the key master switches GATA-3 and T-bet, which results in committing T helper cells to a Th1 phenotype.

Attenuation of pathogenic immune responses during infection with human and simian immunodeficiency virus (HIV/SIV) by the tetracycline derivative minocycline

HIV immune pathogenesis is postulated to involve two major mechanisms: 1) chronic innate immune responses that drive T cell activation and apoptosis and 2) induction of immune regulators that suppress T cell function and proliferation. Both arms are elevated chronically in lymphoid tissues of non-natural hosts, which ultimately develop AIDS. However, these mechanisms are not elevated chronically in natural hosts of SIV infection that avert immune pathogenesis despite similarly high viral loads. In this study we investigated whether minocycline could modulate these pathogenic antiviral responses in non-natural hosts of HIV and SIV. We found that minocycline attenuated in vitro induction of type I interferon (IFN) and the IFN-stimulated genes indoleamine 2,3-dioxygenase (IDO1) and TNF-related apoptosis inducing ligand (TRAIL) in human plasmacytoid dendritic cells and PBMCs exposed to aldrithiol-2 inactivated HIV or infectious influenza virus. Activation-induced TRAIL and expression of cytotoxic T-lymphocyte antigen 4 (CTLA-4) in isolated CD4+ T cells were also reduced by minocycline. Translation of these in vitro findings to in vivo effects, however, were mixed as minocycline significantly reduced markers of activation and activation-induced cell death (CD25, Fas, caspase-3) but did not affect expression of IFNβ or the IFN-stimulated genes IDO1, FasL, or Mx in the spleens of chronically SIV-infected pigtailed macaques. TRAIL expression, reflecting the mixed effects of minocycline on activation and type I IFN stimuli, was reduced by half, but this change was not significant. These results show that minocycline administered after infection may protect against aspects of activation-induced cell death during HIV/SIV immune disease, but that in vitro effects of minocycline on type I IFN responses are not recapitulated in a rapid progressor model in vivo.

Minocycline targets the NF-κB Nexus through suppression of TGF-β1-TAK1-IκB signaling in ovarian cancer

Substantial evidence supports the critical role of NF-κB in ovarian cancer. Minocycline, a tetracycline, has been shown to exhibit beneficial effects in this malignancy through regulation of a cohort of genes that overlap significantly with the NF-κB transcriptome. Here, it was examined whether or not the molecular mechanism could be attributed to modulation of NF-κB signaling using a combination of in vitro and in vivo models. Minocycline suppressed constitutive NF-κB activation in OVCAR-3 and SKOV-3 ovarian carcinoma cells and was correlated with attenuation of IκBα kinase (IKK) activation, IκBα phosphorylation and degradation, and p65 phosphorylation and nuclear translocation. The inhibition of IKK was found to be associated with suppression of TGF-β-activated-kinase-1 (TAK1) activation and its dissociation from TAK1-binding-protein-1 (TAB1), an indispensable functional mediator between TGF-β and TAK1. Further studies demonstrated that minocycline downregulated TGF-β1 expression. Enforced TGF-β1 expression induced NF-κB activity, and minocycline rescued this effect. Consistent with this finding, TGF-β1 knockdown suppressed NF-κB activation and abrogated the inhibitory effect of minocycline on this transcription factor. These results suggest that the minocycline-induced suppression of NF-κB activity is mediated, in part, through inhibition of TGF-β1. Furthermore, the influence of minocycline on NF-κB pathway activation was examined in female nude mice harboring intraperitoneal OVCAR-3 tumors. Both acute and chronic administration of minocycline led to suppression of p65 phosphorylation and nuclear translocation accompanied by downregulation of NF-κB activity and endogenous protein levels of its target gene products. These data reveal the therapeutic potential of minocycline as an agent targeting the pro-oncogenic TGF-β-NF-κB axis in ovarian cancer.

IMPLICATIONS

This preclinical study lends support to the notion that ovarian cancer management would benefit from administration of minocycline.