Switching off key signaling survival molecules to switch on the resolution of inflammation

Pioglitazone as a potential modulator in autoimmune diseases: a review on its effects in systemic lupus erythematosus, psoriasis, inflammatory bowel disease, and multiple sclerosis

INTRODUCTION

Current medications for autoimmune disorders often induce broad-ranging side effects, prompting a growing interest in therapies with more specific immune system modulation. Pioglitazone, known for its anti-diabetic properties, is increasingly recognized for significant immunomodulatory potential. Beyond its traditional use in diabetes management, pioglitazone emerges as a promising therapeutic candidate for autoimmune disorders.

AREAS COVERED

This comprehensive review explores pioglitazone's impact on four prominent autoimmune conditions: systemic lupus erythematosus, psoriasis, inflammatory bowel disease, and multiple sclerosis. We focus on pioglitazone's diverse effects on immune cells and cytokines in these diseases, highlighting its potential as a valuable therapeutic option for autoimmune diseases. Here we have reviewed the latest and most current research literature available on PubMed, based on research published in the last 15 years.

EXPERT OPINION

Pioglitazone as an immunomodulatory agent can regulate T cell differentiation, inhibit inflammatory cytokines, and promote anti-inflammatory macrophages. While further clinical studies are needed to fully understand its mechanisms and optimize treatment strategies, pioglitazone represents a potential therapeutic approach to improve outcomes for patients with these challenging autoimmune conditions. The future of autoimmune disease research may involve personalized treatment approaches, and collaborative efforts to improve patient quality of life.

Antioxidative and Anti-Inflammatory Activities of Rosebud Extracts of Newly Crossbred Roses

Oxidative stress and inflammation are basic pathogenic factors involved in tissue injury and pain, as well as acute and chronic diseases. Since long-term uses of synthetic steroids and non-steroidal anti-inflammatory drugs (NSAIDs) cause severe adverse effects, novel effective materials with minimal side effects are required. In this study, polyphenol content and antioxidative activity of rosebud extracts from 24 newly crossbred Korean roses were analyzed. Among them, Pretty Velvet rosebud extract (PVRE) was found to contain high polyphenols and to show in vitro antioxidative and anti-inflammatory activities. In RAW 264.7 cells stimulated with lipopolysaccharide (LPS), PVRE down-regulated mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and thereby decreased nitric oxide (NO) and prostaglandin E₂ (PGE₂) production. In a subcutaneous air-pouch inflammation model, treatment with PVRE decreased λ-carrageenan-induced tissue exudation, infiltration of inflammatory cells, and inflammatory cytokines such as tumor necrosis factor-α and interleukin-1β concentrations, as achieved with dexamethasone (a representative steroid). Notably, PVRE also inhibited PGE₂, similar to dexamethasone and indomethacin (a representative NSAID). The anti-inflammatory effects of PVRE were confirmed by microscopic findings, attenuating tissue erythema, edema, and inflammatory cell infiltration. These results indicate that PVRE exhibits dual (steroid- and NSAID-like) anti-inflammatory activities by blocking both the iNOS-NO and COX-2-PG pathways, and that PVRE could be a potential candidate as an anti-inflammatory material for diverse tissue injuries.

Possibility of averting cytokine storm in SARS-COV 2 patients using specialized pro-resolving lipid mediators

Fatal "cytokine storms (CS)" observed in critically ill COVID-19 patients are consequences of dysregulated host immune system and over-exuberant inflammatory response. Acute respiratory distress syndrome (ARDS), multi-system organ failure, and eventual death are distinctive symptoms, attributed to higher morbidity and mortality rates among these patients. Consequent efforts to save critical COVID-19 patients via the usage of several novel therapeutic options are put in force. Strategically, drugs being used in such patients are dexamethasone, remdesivir, hydroxychloroquine, etc. along with the approved vaccines. Moreover, it is certain that activation of the resolution process is important for the prevention of chronic diseases. Until recently Inflammation resolution was considered a passive process, rather it's an active biochemical process that can be achieved by the use of specialized pro-resolving mediators (SPMs). These endogenous mediators are an array of atypical lipid metabolites that include Resolvins, lipoxins, maresins, protectins, considered as immunoresolvents, but their role in COVID-19 is ambiguous. Recent evidence from studies such as the randomized clinical trial, in which omega 3 fatty acid was used as supplement to resolve inflammation in COVID-19, suggests that direct supplementation of SPMs or the use of synthetic SPM mimetics (which are still being explored) could enhance the process of resolution by regulating the aberrant inflammatory process and can be useful in pain relief and tissue remodeling. Here we discussed the biosynthesis of SPMs, & their mechanistic pathways contributing to inflammation resolution along with sequence of events leading to CS in COVID-19, with a focus on therapeutic potential of SPMs.

Resolution of Inflammation in Acute Graft-Versus-Host-Disease: Advances and Perspectives

Inflammation is an essential reaction of the immune system to infections and sterile tissue injury. However, uncontrolled or unresolved inflammation can cause tissue damage and contribute to the pathogenesis of various inflammatory diseases. Resolution of inflammation is driven by endogenous molecules, known as pro-resolving mediators, that contribute to dampening inflammatory responses, promoting the resolution of inflammation and the recovery of tissue homeostasis. These mediators have been shown to be useful to decrease inflammatory responses and tissue damage in various models of inflammatory diseases. Graft-versus-host disease (GVHD) is a major unwanted reaction following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is characterized by an exacerbated inflammatory response provoked by antigen disparities between transplant recipient and donor. There is no fully effective treatment or prophylaxis for GVHD. This review explores the effects of several pro-resolving mediators and discusses their potential use as novel therapies in the context of GVHD.

Ethyl 2-Succinate-Anthraquinone Attenuates Inflammatory Response and Oxidative Stress via Regulating NLRP3 Signaling Pathway

Aloe-emodin widely possesses antibacterial, anti-inflammatory, antioxidant, antiviral, and anti-infectious properties. This study investigated the effect of ethyl 2-succinate-anthraquinone (Luhui derivative, LHD) on inflammation. In vitro, a THP-1 macrophage inflammation model, made by 100 ng/ml phorbol-12-myristate-13-acetate (PMA) and 1 μg/ml LPS for 24 h, was constructed. The LHD group (6.25 μmol/L, 12.5 μmol/L, 25 μmol/L, 50 μmol/L) had no effect on THP-1 cell activity, and the expression of IL-6 mRNA was down-regulated in a concentration-dependent manner, of which the 25 μmol/L group had the best inhibitory effect. The migration of THP-1 macrophages induced by LPS was decreased by the LHD. Moreover, the LHD suppressed ROS fluorescence expression by inhibiting MDA expression and increasing SOD activity. In vivo, we revealed that the LHD, in different doses (6.25 mg/kg, 12.5 mg/kg, 25 mg/kg, 50 mg/kg), has a protective effect on stress physiological responses by assessing the body temperature of mice. Interestingly, acute lung injury (e.g., the structure of the alveoli disappeared and capillaries in the alveolar wall were dilated and congested) and liver damage (e.g., hepatocyte swelling, neutrophil infiltration, and hepatocyte apoptosis) were obviously improved at the same condition. Furthermore, we initially confirmed that the LHD can down-regulate the expression of NLRP3, IL-1β, and caspase-1 proteins, thereby mediating the NLRP3 inflammasome signaling pathway to produce anti-inflammatory effects. In conclusion, our results indicate that the LHD exerts anti-inflammatory activity via regulating the NLRP3 signaling pathway, inhibition of oxidative stress, and THP-1 macrophage migration.

Oral Formulation of Angiotensin-(1-7) Promotes Therapeutic Actions in a Model of Eosinophilic and Neutrophilic Asthma

The presence of eosinophils and neutrophils in the lungs of asthmatic patients is associated with the severity of the disease and resistance to corticosteroids. Thus, defective resolution of eosinophilic and neutrophilic inflammation is importantly related to exacerbation of asthma. In this study, we investigated a therapeutic action of angiotensin-(1-7) (Ang-(1-7)) in a model of asthma induced by ovalbumin (OVA) and lipopolysaccharide (LPS). Balb-c mice were sensitized and challenged with OVA. Twenty-three hours after the last OVA challenge, experimental groups received LPS, and 1 h and 7 h later, mice were treated with oral formulation of Ang-(1-7). On the next day, 45 h after the last challenge with OVA, mice were subjected to a test of motor and exploratory behavior; 3 h later, lung function was evaluated, and bronchoalveolar lavage fluid (BALF) and lungs were collected. Motor and exploratory activities were lower in OVA + LPS-challenged mice. Treatment with Ang-(1-7) improved these behaviors, normalized lung function, and reduced eosinophil, neutrophil, myeloperoxidase (MPO), eosinophilic peroxidase (EPO), and ERK1/2 phosphorylation (p-ERK1/2) in the lungs. In addition, Ang-(1-7) decreased the deposition of mucus and extracellular matrix in the airways. These results extended those of previous studies by demonstrating that oral administration of Ang-(1-7) at the peak of pulmonary inflammation can be valuable for the treatment of neutrophil- and eosinophil-mediated asthma. Therefore, these findings potentially provide a new drug to reverse the natural history of the disease, unlike the current standards of care that manage the disease symptoms at best.

Evaluation of the genotoxic and antigenotoxic potential of lignin-derivative BP-C2 in the comet assay in vivo

The genotoxic and antigenotoxic potential of BP-C2, a novel lignin-derived polyphenolic composition with ammonium molybdate, was investigated as a radioprotector/radiomitigator for civil applications and as a medical countermeasure for radiation emergencies. Using the alkaline comet assay and methyl methanesulfonate (MMS, 40 mg/kg) as the DNA-damaging agent, these effects of BP-C2 on liver, bone marrow cells and blood leukocytes in rats were studied. The DNA damage was estimated by the DNA content in the comet tail (TDNA, %) 1, 6 and 18 h post exposure to MMS. BP-C2 at doses of 20, 200 and 2000 mg/kg did not exert genotoxic activity in the tested tissues in rats. BP-C2 administered at doses of 20, 100 and 200 mg/kg 1 h before MMS significantly (p < 0.01) mitigated MMS-induced DNA damage, showing a strong genoprotective effect in the liver. In blood leukocytes and bone marrow samples of animals treated with BP-C2, the TDNA % was slightly higher than in the negative control (vehicle) but significantly lower than in the positive control (MMS). Thus, BP-C2 exerted a genoprotective effect against MMS-induced DNA damage to a greater extent towards liver cells, requiring further evaluation of this substance as a genoprotective agent.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast

Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.

Sensory Ganglia-Specific TNF Expression Is Associated With Persistent Nociception After Resolution of Inflammation

Joint pain is a distressing symptom of arthritis, and it is frequently persistent even after treatments which reduce local inflammation. Continuous production of algogenic factors activate/sensitize nociceptors in the joint structures and contribute to persistent pain, a challenging and difficult condition to treat. TNF is a crucial cytokine for the pathogenesis of several rheumatic diseases, and its inhibition is a mainstay of treatment to control joint symptoms, including pain. Here, we sought to investigate the inflammatory changes and the role of TNF in dorsal root ganglia (DRG) during persistent hypernociception after the resolution of acute joint inflammation. Using a model of antigen-induced arthritis, the peak of joint inflammation occurred 12–24 h after local antigen injection and was characterized by an intense influx of neutrophils, pro-inflammatory cytokine production, and joint damage. We found that inflammatory parameters in the joint returned to basal levels between 6 and 8 days after antigen-challenge, characterizing the resolving phase of joint inflammation. Mechanical hyperalgesia was persistent up to 14 days after joint insult. The persistent nociception was associated with the inflammatory status of DRG after cessation of acute joint inflammation. The late state of neuroinflammation in the ipsilateral side was evidenced by gene expression of TNF, TNFR2, IL-6, IL-1β, CXCL2, COX2, and iNOS in lumbar DRG (L3-L5) and leukocyte adhesion in the lumbar intumescent vessels between days 6 and 8. Moreover, there were signs of resident macrophage activation in DRG, as evidenced by an increase in Iba1-positive cells. Intrathecal or systemic injection of etanercept, an agent clinically utilized for TNF neutralization, at day 7 post arthritis induction, alleviated the persistent joint hyperalgesia by specific action in DRG. Our data suggest that neuroinflammation in DRG after the resolution of acute joint inflammation drives continuous neural sensitization resulting in persistent joint nociception in a TNF-dependent mechanism.

Advancements of Annexin A1 in inflammation and tumorigenesis

Annexin A1 is a Ca²⁺-dependent phospholipid binding protein involved in a variety of pathophysiological processes. Accumulated evidence has indicated that Annexin A1 has important functions in cell proliferation, apoptosis, differentiation, metastasis, and inflammatory response. Moreover, the abnormal expression of Annexin A1 is closely related to the occurrence and development of tumors. In this review article, we focus on the structure and function of Annexin A1 protein, especially the recent evidence of Annexin A1 in the pathophysiological role of inflammatory and cancer. This summary will be very important for further investigation of the pathophysiological role of Annexin A1 and for the development of novel therapeutics of inflammatory and cancer based on targeting Annexin A1 protein.

Formyl peptide receptor-2 is decreased in foetal growth restriction and contributes to placental dysfunction

STUDY QUESTION

What is the association between placental formyl peptide receptor 2 (FPR2) and trophoblast and endothelial functions in pregnancies affected by foetal growth restriction (FGR)?

SUMMARY ANSWER

Reduced FPR2 placental expression in idiopathic FGR results in significantly altered trophoblast differentiation and endothelial function in vitro.

WHAT IS KNOWN ALREADY

FGR is associated with placental insufficiency, where defective trophoblast and endothelial functions contribute to reduced feto-placental growth.

STUDY DESIGN, SIZE, DURATION

The expression of FPR2 in placental tissues from human pregnancies complicated with FGR was compared to that in gestation-matched uncomplicated control pregnancies (n = 25 from each group). Fpr2 expression was also determined in placental tissues obtained from a murine model of FGR (n = 4). The functional role of FPR2 in primary trophoblasts and endothelial cells in vitro was assessed in diverse assays in a time-dependent manner.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Placentae from third-trimester pregnancies complicated by idiopathic FGR (n = 25) and those from gestation-matched pregnancies with appropriately grown infants as controls (n = 25) were collected at gestation 27-40 weeks. Placental tissues were also collected from a spontaneous CBA/CaH × DBA/2 J murine model of FGR. Placental FPR2/Fpr2 mRNA expression was determined by real-time PCR, while protein expression was examined by immunoblotting and immunohistochemistry. siRNA transfection was used to silence FPR2 expression in primary trophoblasts and in human umbilical vein endothelial cells (HUVEC), and the quantitation of cytokines, chemokines and apoptosis was performed following a cDNA array analyses. Functional effects of trophoblast differentiation were measured using HCGB/β-hCG and syncytin-2 expression as well as markers of apoptosis, tumour protein 53 (TP53), caspase 8, B cell lymphoma 2 (BCL2) and BCL associated X (BAX). Endothelial function was assessed by proliferation, network formation and permeability assays.

MAIN RESULTS AND THE ROLE OF CHANCE

Placental FPR2/Fpr2 expression was significantly decreased in FGR placentae (n = 25, P < 0.05) as well as in murine FGR placentae compared to controls (n = 4, P < 0.05). FPR2 siRNA (siFPR2) in term trophoblasts significantly increased differentiation markers, HCGB and syncytin-2; cytokines, interleukin (IL)-6, CXCL8; and apoptotic markers, TP53, caspase 8 and BAX, but significantly reduced the expression of the chemokines CXCL12 and its receptors CXCR4 and CXCR7; CXCL16 and its receptor, CXCR6; and cytokine, IL-10, compared with control siRNA (siCONT). Treatment of HUVECs with siFPR2 significantly reduced proliferation and endothelial tube formation, but significantly increased permeability of HUVECs.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

Reduced expression of placental FPR2/Fpr2 was observed in the third trimester at delivery after development of FGR, suggesting that FPR2 is associated with FGR pregnancies. However, there is a possibility that the decreased placental FPR2 observed in FGR may be a consequence rather than a cause of FGR, although our in vitro functional analyses using primary trophoblasts and endothelial cells suggest that FPR2 may have a direct or indirect regulatory role on trophoblast differentiation and endothelial function in FGR.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study linking placental FPR2 expression with changes in the trophoblast and endothelial functions that may explain the placental insufficiency observed in FGR.

STUDY FUNDING/COMPETING INTERESTS

P.M. and P.R.E. received funding from the Australian Institute of Musculoskeletal Science, Western Health, St. Albans, Victoria 3021, Australia. M.L. is supported by a Career Development Fellowship from the National Health and Medical Research Council (NHMRC; Grant no. 1047025). Monash Health is supported by the Victorian Government's Operational Infrastructure Support Programme. The authors declare that there is no conflict of interest in publishing this work.

Lung

In the present chapter, we review and summarize current advances on the role of angiotensin-(1-7) [Ang-(1-7)] in the pathophysiology of main lung diseases: pulmonary hypertension (PH), acute respiratory distress syndrome (ARDS), asthma, and pulmonary fibrosis. Understanding the involvement of renin angiotensin system (RAS) in pulmonary inflammation may open new therapeutic possibilities for the treatment of respiratory diseases. Studies to date showed that Ang-(1-7) presents anti-inflammatory, antifibrotic activities and reduces pulmonary remodeling. These actions support the development of new pharmacological therapies based on the increase in Ang-(1-7) in the lungs to improve the treatment of inflammatory diseases.

Resolution of inflammation in periodontitis: a review

Inflammation is a physiological response to an injury or infection. It is supposed to be self-limiting, stopping when the situation recovers to normal to protect the tissue. This self-limiting action is called "resolution of inflammation". Currently, periodontitis is thought to be the result of failed resolution of inflammation; specifically, it is the result of excessive inflammation that leads to gingival recession and alveolar bone loss. In this review, we will focus on the processes of resolution of inflammation in periodontitis, which may be a therapeutic target of periodontitis.

Angiotensin-(1-7) Promotes Resolution of Eosinophilic Inflammation in an Experimental Model of Asthma

Defective apoptosis of eosinophils, the main leukocyte in the pathogenesis of asthma, and delay in its removal lead to lung damage and loss of pulmonary function due to failure in the resolution of inflammation. Here, we investigated the ability of angiotensin-(1-7) [Ang-(1-7)], a pivotal peptide of the renin-angiotensin system, to promote resolution of an allergic lung inflammatory response. Balb/c mice were sensitized and challenged with ovalbumin and treated with Ang-(1-7) at the peak of the inflammatory process. Bronchoalveolar lavage (BAL) fluid and lungs were collected 24 h after treatment. Different lung lobes were processed for histology to evaluate inflammatory cell infiltration, airway and pulmonary remodeling, total collagen staining, and measurements of (i) collagen I and III mRNA expression by qRT-PCR; (ii) ERK1/2, IκB-α, and GATA3 protein levels by Western blotting; and (iii) eosinophilic peroxidase activity. Total number of inflammatory cells, proportion of apoptotic eosinophils and immunofluorescence for caspase 3 and NF-κB in leukocytes were evaluated in the BAL. Mas receptor immunostaining was evaluated in mouse and human eosinophils. Engulfment of human polimorphonuclear cells by macrophages, efferocytosis, was evaluated in vivo. Ang-(1-7) reduced eosinophils in the lung and in the BAL, increased the number of apoptotic eosinophils, shown by histology criteria and by increase in caspase 3 immunostaining. Furthermore, Ang-(1-7) decreased NF-kB immunostaining in eosinophils, reduced GATA3, ERK1/2, and IκB-α expression in the lung and decreased pulmonary remodeling and collagen deposition. Importantly, Ang-(1-7) increased efferocytosis. Our results demonstrate, for the first time, Ang-(1-7) activates events that are crucial for resolution of the inflammatory process of asthma and promotion of the return of lung homeostasis, indicating Ang-(1-7) as novel endogenous inflammation-resolving mediator.

Angiotensin-(1-7) Promotes Resolution of Neutrophilic Inflammation in a Model of Antigen-Induced Arthritis in Mice

Defective resolution of inflammation may be crucial for the initiation and development of chronic inflammatory diseases, such as arthritis. Therefore, it has been suggested that therapeutic strategies based on molecules that facilitate inflammation resolution present great potential for the treatment of chronic inflammatory diseases. In this study, we investigated the effects and role of angiotensin-(1-7) [Ang-(1-7)] in driving resolution of neutrophilic inflammation in a model of arthritis. For this purpose, male C57BL/6 mice were subjected to antigen-induced arthritis and treated with Ang-(1-7) at the peak of the inflammatory process. Analysis of the number of inflammatory cells, apoptosis, and immunofluorescence for NF-κB was performed in the exudate collected from the knee cavity. Neutrophil accumulation in periarticular tissue was measured by assaying myeloperoxidase activity. Apoptosis of human neutrophil after treatment with Ang-(1-7) was evaluated morphologically and by flow cytometry, and NF-κB phosphorylation by immunofluorescence. Efferocytosis was evaluated in vivo. Therapeutic treatment with Ang-(1-7) at the peak of inflammation promoted resolution, an effect associated with caspase-dependent neutrophils apoptosis and NF-κB inhibition. Importantly, Ang-(1-7) was also able to induce apoptosis of human neutrophils, an effect associated with NF-κB inhibition. The pro-resolving effects of Ang-(1-7) were inhibited by the Mas receptor antagonist A779. Finally, we showed that Ang-(1-7) increased the efferocytic ability of murine macrophages. Our results clearly demonstrate that Ang-(1-7) resolves neutrophilic inflammation in vivo acting in two key step of resolution: apoptosis of neutrophils and their removal by efferocytosis. Ang-(1-7) is a novel mediator of resolution of inflammation.

EVALUATION OF THE ANTI-INFLAMMATORY CAPACITY OF BETA-SITOSTEROL IN RODENT ASSAYS

BACKGROUND

Beta-sitosterol (BS) is a compound discovered to be present in numerous plants. A number of interesting biomedical properties have been attributed to BS, including immuno-modulating and anti-inflammatory activities. Therefore, the aim of this report was to evaluate its anti-inflammatory capacity by applying various rodent experimental tests.

METHODS

To carry out the objective of the study we applied the methods indicated here. Two of the adopted methods were based on the passive reverse Arthus reaction: the rat paw edema test and the rat pleurisy assay. We also applied two methods related with the non-specific acute inflammation: the mouse ear edema test, and the mouse mieloperoxidase activity assay.

RESULTS

The results obtained in all tests established a significant anti-inflammatory potential of BS. In the rat paw edema test we found an inhibitory effect which goes from 50-70%; in the rat pleurisy assay our findings with respect to the volume of pleural exuded showed a reduction of 46%, as well as a 20% low amount of neutrophils in comparison with the level of the control group. In the mouse ear edema test we found a mean inflammatory inhibition of 75%, and with respect to mieloproxidase activity the results showed a significant inhibition induced by the three doses of BS.

CONCLUSIONS

In the present study we determined a potent anti-inflammatory capacity of BS in specific and non-specific types of acute inflammation in rodents.

Aqueous extract from Ipomoea asarifolia (Convolvulaceae) leaves and its phenolic compounds have anti-inflammatory activity in murine models of edema, peritonitis and air-pouch inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Ipomoea asarifolia (Desr.) Roem. and Schult.(Convolvulaceae), popularly known as salsa or salsa-brava, is a plant of which the decoction of leaves is used in folk medicine to treat various inflammatory disorders such of dermatitis, scabies, symptoms of syphilis, skin ulcers and external wounds. However, little is known about possible compounds and mechanisms of action of the plant to support the activities reported by popular use.

AIM OF THE STUDY

The study aimed to identify bioactive molecules present in the crude extract of I. asarifolia leaves and investigate the anti-inflammatory potential of this extract in different experimental in vivo models to improve the understanding on that activity.

MATERIAL AND METHODS

Aqueous extract of I. asarifolia leaves was prepared by decoction (1:10 m/v) and its chromatographic profile was obtained by high performance liquid chromatography coupled with diode array detector (HPLC-DAD) and liquid chromatography diode array detector coupled with mass spectrometry (LC-DAD-MS). The potential anti-inflammatory activity of the extract was assessed using the following in vivo models: xylene-induced ear edema (20, 30 and 40mg/kg), evaluating the degree of edema formation; carrageenan-induced peritonitis (10, 20 and 30mg/kg), evaluating leukocyte migration and cytokine levels (IL-1β, IL-6, IL-12 and TNF-α) at 4h; zymosan-induced air pouch inflammation (20, 30 and 40mg/kg), evaluating the kinetics of leukocyte migration by total and differential counts at 6, 24 and 48h. The same tests were conducted using pure compounds identified in the aqueous extract from I. asarifolia leaves in different doses for each experimental model.

RESULTS

The compounds identified in the aqueous extract of I. asarifolia leaves by HPLC-DAD and LC-DAD-MS were rutin, chlorogenic acid and caffeic acid. The extract significantly reduced ear edema induced by xylene (81%, 85% and 86% for doses of 20, 30 and 40mg/kg, respectively, p<0.001), as well as cell migration in experimental models of peritonitis (70%, 78% and 83% for doses of 10, 20 and 30mg/kg, respectively, p<0.001) and air pouch inflammation (58%, 67% and 53% for doses of 20, 30 and 40mg/kg, respectively, p<0.001). In addition, the extract demonstrated the ability to significantly inhibit the production of cytokines IL-1β, IL-6, IL-12 and TNF-α (p<0.001). The secondary metabolites tested (rutin, chlorogenic acid and caffeic acid) also showed the ability to significantly (p<0.001) decrease the parameters analyzed above.

CONCLUSION

This is the first study to identify and confirm these phenolic compounds in I. asarifolia leaves extract and to suggest that these compounds contribute to the anti-inflammatory activity in vivo, as reported by ethnomedicinal use of this plant. Through the different experimental models performed, we can conclude that the results obtained with the aqueous extract from I. asarifolia leaves support its popular use for the treatment of inflammatory disorders.

Effects of budlein A on human neutrophils and lymphocytes

OBJECTIVE

In this study, we evaluated whether budlein A modulates the activation of innate and adaptive immune cells such as neutrophils and lymphocytes.

MATERIAL AND METHODS

Our research group has investigated several plant species and several compounds have been isolated, identified, and their medical potential evaluated. Budlein A is a SL isolated from the species Aldama buddlejiformis and A. robusta (Asteraceae) and shows anti-inflammatory and anti-nociceptive activities. Advances in understanding how plant-derived substances modulate the activation of innate and adaptive immune cells have led to the development of new therapies for human diseases.

RESULTS

Budlein A inhibited MPO activity, IL-6, CXCL8, IL-10, and IL-12 production and induces neutrophil apoptosis. In contrast, budlein A inhibited lymphocyte proliferation and IL-2, IL-10, TGF-β, and IFN-γ production, but it did not lead to cell death.

CONCLUSIONS

Collectively, our results indicate that budlein A shows distinct immunomodulatory effects on immune cells.

Contribution of Human Fibroblasts and Endothelial Cells to the Hallmarks of Inflammation as Determined by Proteome Profiling

In order to systematically analyze proteins fulfilling effector functionalities during inflammation, here we present a comprehensive proteome study of inflammatory activated primary human endothelial cells and fibroblasts. Cells were stimulated with interleukin 1-β and fractionated in order to obtain secreted, cytoplasmic and nuclear protein fractions. Proteins were submitted to a data-dependent bottom up analytical platform using a QExactive orbitrap and the MaxQuant software for protein identification and label-free quantification. Results were further combined with similarly generated data previously obtained from the analysis of inflammatory activated peripheral blood mononuclear cells. Applying a false discovery rate of less than 0.01 at both, peptide and protein level, a total of 8370 protein groups assembled from 117,599 peptides was identified; mass spectrometry data have been made fully accessible via ProteomeXchange with identifier PXD003406 to PXD003417.Comparative proteome analysis allowed us to determine common and cell type-specific inflammation signatures comprising novel candidate marker molecules and related expression patterns of transcription factors. Cardinal features of inflammation such as interleukin 1-β processing and the interferon response differed substantially between the investigated cells. Furthermore, cells also exerted similar inflammation-related tasks; however, by making use of different sets of proteins. Hallmarks of inflammation thus emerged, including angiogenesis, extracellular matrix reorganization, adaptive and innate immune responses, oxidative stress response, cell proliferation and differentiation, cell adhesion and migration in addition to monosaccharide metabolic processes, representing both, common and cell type-specific responsibilities of cells during inflammation.

Proresolving Actions of Synthetic and Natural Protease Inhibitors Are Mediated by Annexin A1

Annexin A1 (AnxA1) is a glucocorticoid-regulated protein endowed with anti-inflammatory and proresolving properties. Intact AnxA1 is a 37-kDa protein that may be cleaved in vivo at the N-terminal region by neutrophil proteases including elastase and proteinase-3, generating the 33-kDa isoform that is largely inactive. In this study, we investigated the dynamics of AnxA1 expression and the effects of synthetic (sivelestat [SIV]; Eglin) and natural (secretory leukocyte protease inhibitor [SLPI]; Elafin) protease inhibitors on the resolution of LPS-induced inflammation. During the settings of LPS inflammation AnxA1 cleavage associated closely with the peak of neutrophil and elastase expression and activity. SLPI expression increased during resolving phase of the pleurisy. Therapeutic treatment of LPS-challenge mice with recombinant human SLPI or Elafin accelerated resolution, an effect associated with increased numbers of apoptotic neutrophils in the pleural exudates, inhibition of elastase, and modulation of the survival-controlling proteins NF-κB and Mcl-1. Similar effects were observed with SIV, which dose-dependently inhibited neutrophil elastase and shortened resolution intervals. Mechanistically, SIV-induced resolution was caspase-dependent, associated to increased levels of intact AnxA1 and decreased expression of NF-κB and Mcl-1. The proresolving effect of antiproteases was also observed in a model of monosodium urate crystals-induced inflammation. SIV skewed macrophages toward resolving phenotypes and enhanced efferocytosis of apoptotic neutrophils. A neutralizing antiserum against AnxA1 and a nonselective antagonist of AnxA1 receptor abolished the accelerated resolution promoted by SIV. Collectively, these results show that elastase inhibition not only inhibits inflammation but actually promotes resolution, and this response is mediated by protection of endogenous intact AnxA1 with ensuing augmentation of neutrophil apoptosis.

Induction of eosinophil apoptosis by hydrogen peroxide promotes the resolution of allergic inflammation

Eosinophils are effector cells that have an important role in the pathogenesis of allergic disease. Defective removal of these cells likely leads to chronic inflammatory diseases such as asthma. Thus, there is great interest in understanding the mechanisms responsible for the elimination of eosinophils from inflammatory sites. Previous studies have demonstrated a role for certain mediators and molecular pathways responsible for the survival and death of leukocytes at sites of inflammation. Reactive oxygen species have been described as proinflammatory mediators but their role in the resolution phase of inflammation is poorly understood. The aim of this study was to investigate the effect of reactive oxygen species in the resolution of allergic inflammatory responses. An eosinophilic cell line (Eol-1) was treated with hydrogen peroxide and apoptosis was measured. Allergic inflammation was induced in ovalbumin sensitized and challenged mouse models and reactive oxygen species were administered at the peak of inflammatory cell infiltrate. Inflammatory cell numbers, cytokine and chemokine levels, mucus production, inflammatory cell apoptosis and peribronchiolar matrix deposition was quantified in the lungs. Resistance and elastance were measured at baseline and after aerosolized methacholine. Hydrogen peroxide accelerates resolution of airway inflammation by induction of caspase-dependent apoptosis of eosinophils and decrease remodeling, mucus deposition, inflammatory cytokine production and airway hyperreactivity. Moreover, the inhibition of reactive oxygen species production by apocynin or in gp91^phox−/− mice prolonged the inflammatory response. Hydrogen peroxide induces Eol-1 apoptosis in vitro and enhances the resolution of inflammation and improves lung function in vivo by inducing caspase-dependent apoptosis of eosinophils.