Interleukin (IL) 4 and IL-13 act on human lung fibroblasts. Implication in asthma

A review of the pathophysiology and the role of ion channels on bronchial asthma

Asthma is one of the main non-communicable chronic diseases and affects a huge portion of the population. It is a multifactorial disease, classified into several phenotypes, being the allergic the most frequent. The pathophysiological mechanism of asthma involves a Th2-type immune response, with high concentrations of allergen-specific immunoglobulin E, eosinophilia, hyperreactivity and airway remodeling. These mechanisms are orchestrated by intracellular signaling from effector cells, such as lymphocytes and eosinophils. Ion channels play a fundamental role in maintaining the inflammatory response on asthma. In particular, transient receptor potential (TRP), stock-operated Ca2+ channels (SOCs), Ca2+-activated K+ channels (IKCa and BKCa), calcium-activated chloride channel (TMEM16A), cystic fibrosis transmembrane conductance regulator (CFTR), piezo-type mechanosensitive ion channel component 1 (PIEZO1) and purinergic P2X receptor (P2X). The recognition of the participation of these channels in the pathological process of asthma is important, as they become pharmacological targets for the discovery of new drugs and/or pharmacological tools that effectively help the pharmacotherapeutic follow-up of this disease, as well as the more specific mechanisms involved in worsening asthma.

Single-Cell Profiling of Cells in the Lung of a Patient with Chronic Hypersensitivity Pneumonitis Reveals Inflammatory Niche with Abundant CD39+ T Cells with Functional ATPase Phenotype: A Case Study

This study investigated immune cell characteristics in chronic hypersensitivity pneumonitis (HP), focusing on CD39-expressing cells' impact on inflammation and tissue remodelling. Lung tissue from an HP patient was analysed using single-cell transcriptomics, flow cytometry, and gene expression profiling. The tissue revealed diverse cell types like macrophages, T cells, fibroblasts, and regulatory T cells (Tregs). CD39-expressing Tregs exhibited heightened ATP hydrolysis capacity and regulatory gene expression. CD39hi cells displayed markers of both Tregs and proinflammatory Th17 cells, suggesting transitional properties. Communication networks involving molecules like SPP1, collagen, CSF1, and IL-1β were identified, hinting at interactions between cell types in HP pathogenesis. This research provides insights into the immune response and cell interactions in chronic HP. CD39-expressing cells dual nature as Tregs and Th17 cells suggests a role in modulating lung inflammation, potentially affecting disease progression. These findings lay the groundwork for further research, underscoring CD39-expressing cells as potential therapeutic targets in HP.

Immune dysregulation and pathophysiology of alcohol consumption and alcoholic liver disease

Alcoholic liver disease (ALD) is a clinical-pathologic entity caused by the chronic excessive consumption of alcohol. The disease includes a broad spectrum of anomalies at the cellular and tissual level that can cause acute-on-chronic (alcoholic hepatitis) or chronic (fibrosis, cirrhosis, hepatocellular cancer) injury, having a great impact on morbidity and mortality worldwide. Alcohol is metabolized mainly in the liver. During alcohol metabolism, toxic metabolites, such as acetaldehyde and oxygen reactive species, are produced. At the intestinal level, alcohol consumption can cause dysbiosis and alter intestinal permeability, promoting the translocation of bacterial products and causing the production of inflammatory cytokines in the liver, perpetuating local inflammation during the progression of ALD. Different study groups have reported systemic inflammatory response disturbances, but reports containing a compendium of the cytokines and cells involved in the pathophysiology of the disease, from the early stages, are difficult to find. In the present review article, the role of the inflammatory mediators involved in ALD progression are described, from risky patterns of alcohol consumption to advanced stages of the disease, with the aim of understanding the involvement of immune dysregulation in the pathophysiology of ALD.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

Inhibition of ROCK ameliorates pulmonary fibrosis by suppressing M2 macrophage polarisation through phosphorylation of STAT3

BACKGROUND

Emerging evidence provides mechanistic insights into the pathogenesis of pulmonary fibrosis (PF), and rare anti-PF therapeutic method has promising effect in its treatment. Rho-associated coiled-coil kinases (ROCK) inhibition significantly ameliorates bleomycin-induced PF and decreases macrophage infiltration, but the mechanism remains unclear. We established bleomycin and radiation-induced PF to identify the activity of WXWH0265, a newly designed unselective ROCK inhibitor in regulating macrophages.

METHODS

Bleomycin-induced PF was induced by intratracheal instillation and radiation-induced PF was induced by bilateral thoracic irradiation. Histopathological techniques (haematoxylin and eosin, Masson's trichrome and immunohistochemistry) and hydroxyproline were used to evaluate PF severity. Western blot, quantitative real-time reverse transcription-polymerase chain reaction and flow cytometry were performed to explore the underlying mechanisms. Bone marrow-derived macrophages (BMDMs) were used to verify their therapeutic effect. Clodronate liposomes were applied to deplete macrophages and to identify the therapeutic effect of WXWH0265.

RESULTS

Therapeutic administration of ROCK inhibitor ameliorates bleomycin-induced PF by inhibiting M2 macrophages polarisation. ROCK inhibitor showed no significant anti-fibrotic effect in macrophages-depleted mice. Treatment with WXWH0265 demonstrated superior protection effect in bleomycin-induced PF compared with positive drugs. In radiation-induced PF, ROCK inhibitor effectively ameliorated PF. Fibroblasts co-cultured with supernatant from various M2 macrophages phenotypes revealed that M2 macrophages stimulated by interleukin-4 promoted extracellular matrix production. Polarisation of M2 macrophages was inhibited by ROCK inhibitor treatment in vitro. The p-signal transducer and activator of transcription 3 (STAT3) in lung tissue and BMDMs was significantly decreased in PF in vivo and vitro after treated with ROCK inhibitors.

CONCLUSION

Inhibiting ROCK could significantly attenuate bleomycin- and radiation-induced PF by regulating the macrophages polarisation via phosphorylation of STAT3. WXWH0265 is a kind of efficient unselective ROCK inhibitor in ameliorating PF. Furthermore, the results provide empirical evidence that ROCK inhibitor, WXWH0265 is a potential drug to prevent the development of PF.

IL-13 Regulates Orai1 Expression in Human Bronchial Smooth Muscle Cells and Airway Remodeling in Asthma Mice Model via LncRNA H19

Background

Increased proliferation and hypertrophy of airway smooth muscle cells (ASMCs) contribute substantially to airway remodeling in asthma. Interleukin (IL)-13 regulates ASMC proliferation by increasing Orai1 expression, the pore-forming subunit of store-operated Ca²⁺ entry (SOCE). The underlying mechanisms of this effect are not fully understood.

Methods

Bioinformatic analysis identified an interaction between microRNA 93-5p (miR-93-5p) and long non-coding RNA (lncRNA) H19, and between miR-93-5p and Orai1. RNA interference was used to investigate H19 knockdown on IL-13-induced proliferation and migration of in vitro cultured human bronchial smooth muscle cells (hBSMCs). Functional relevance of H19 in airway inflammation and airway remodeling was investigated in murine models of acute and chronic asthma.

Results

IL-13 concentration-dependently increased the expression of H19 and Orai1 and decreased the expression of miR-93-5p in hBSMCs. H19 knockdown partly reversed the effects of IL-13 on the expression of miR-93-5p and Orai1 and attenuated the proliferation and migration of hBSMCs promoted by IL-13. IL-13-promoted expression of Orai1 was attenuated by miR-93-5p mimic and increased by miR-93-5p inhibitor. IL-13-promoted proliferation of hBSMCs was increased by miR-93-5p inhibitor but not affected by miR-93-5p mimic, whereas IL-13-promoted migration of hBSMCs was increased by miR-93-5p inhibitor and attenuated by miR-93-5p mimic. The inhibiting effect of H19 knockdown on IL-13-induced Orai1 expression and the proliferation and migration of hBSMCs was counteracted by miR-93-5p inhibitor but only marginally or not impacted by miR-93-5p mimic. The expression of H19 and Orai1 was higher in the lungs of asthmatic mice than in control mice. In asthmatic mice, H19 siRNA reduced Orai1 expression, inflammatory cell infiltration, goblet cell hyperplasia, collagen deposition and smooth muscle mass in the lungs.

Conclusion

H19 may mediate the effects of IL-13 on Orai1 expression by inhibition of miR-93-5p in hBSMCs. H19 may be a therapeutic target for airway inflammation and airway remodeling.

CINS: Cell Interaction Network inference from Single cell expression data

Studies comparing single cell RNA-Seq (scRNA-Seq) data between conditions mainly focus on differences in the proportion of cell types or on differentially expressed genes. In many cases these differences are driven by changes in cell interactions which are challenging to infer without spatial information. To determine cell-cell interactions that differ between conditions we developed the Cell Interaction Network Inference (CINS) pipeline. CINS combines Bayesian network analysis with regression-based modeling to identify differential cell type interactions and the proteins that underlie them. We tested CINS on a disease case control and on an aging mouse dataset. In both cases CINS correctly identifies cell type interactions and the ligands involved in these interactions improving on prior methods suggested for cell interaction predictions. We performed additional mouse aging scRNA-Seq experiments which further support the interactions identified by CINS.

The role of immune response in the pathogenesis of idiopathic pulmonary fibrosis: far beyond the Th1/Th2 imbalance

INTRODUCTION

. Idiopathic pulmonary fibrosis (IPF) is a chronic disease of unknown origin characterized by progressive scarring of the lung leading to irreversible loss of function. Despite the availability of two drugs that are able to slow down disease progression, IPF remains a deadly disease. The pathogenesis of IPF is poorly understood, but a dysregulated wound healing response following recurrent alveolar epithelial injury is thought to be crucial. Areas covered. In the last few years, the role of the immune system in IPF pathobiology has been reconsidered; indeed, recent data suggest that a dysfunctional immune system may promote and unfavorable interplay with pro-fibrotic pathways thus acting as a cofactor in disease development and progression. In this article, we review and critically discuss the role of T cells in the pathogenesis and progression of IPF in the attempt to highlight ways in which further research in this area may enable the development of targeted immunomodulatory therapies for this dreadful disease.

EXPERT OPINION

A better understanding of T cells interactions has the potential to facilitate the development of immune modulators targeting multiple T cell-mediated pathways thus halting disease initiation and progression.

Increased inflammatory markers in adult patients born with an atrial septal defect

Patients with atrial septal defect (ASD) have higher mortality and higher risk of atrial fibrillation, heart failure, pneumonia, and stroke than the general population even if the ASD closes spontaneously in childhood. The reason for the long-term complications remains unknown. Since many of the complications can be linked up with alterations in inflammatory response, we speculate that inflammation may contribute to the association between ASD and morbidity and mortality. We investigated inflammatory activity in adults with an ASD compared with controls. We included 126 adults with an unrepaired ASD. A group of healthy controls were recruited as comparison group (n = 23). Serum samples were analyzed for 92 inflammation-related protein biomarkers using a proximity extension assay. A pathway enrichment analysis was performed using Reactome database. Out of 92 biomarkers, 73 were eligible for data analysis. Increased levels of 14 (19%) biomarkers were found in patients with open ASD and 24 (33%) biomarkers in patients with spontaneously closed defects compared with controls (p < 0.05). Multiple inflammatory pathways showed stronger enrichment in both patient groups when compared with controls. In conclusion, inflammatory activity is altered in adult patients with an unrepaired ASD compared with healthy controls. The increased inflammatory burden of patients with an unrepaired ASD may contribute to the development of morbidities.

Modulation of IL-4/IL-13 cytokine signaling in the context of allergic disease

Aberrant activation of CD4 T_H2 cells and excessive production of T_H2 cytokines such as IL-4 and IL-13 have been implicated in the pathogenesis of allergic diseases. Generally, IL-4 and IL-13 utilize Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways for induction of inflammatory gene expression and the effector functions associated with disease pathology in many allergic diseases. However, it is increasingly clear that JAK/STAT pathways activated by IL-4/IL-13 can themselves be modulated in the presence of other intracellular signaling programs, thereby changing the overall tone and/or magnitude of IL-4/IL-13 signaling. Apart from direct activation of the canonic JAK/STAT pathways, IL-4 and IL-13 also induce proinflammatory gene expression and effector functions through activation of additional signaling cascades. These alternative signaling cascades contribute to several specific aspects of IL-4/IL-13-associated cellular and molecular responses. A more complete understanding of IL-4/IL-13 signaling pathways, including the precise conditions under which noncanonic signaling pathways are activated, and the impact of these pathways on cellular- and host-level responses, will better allow us to design agents that target specific pathologic outcomes or tailor therapies for the treatment of uncommon disease endotypes.

Sulforaphane inhibits cytokine-stimulated chemokine and adhesion molecule expressions in human corneal fibroblasts: Involvement of the MAPK, STAT, and NF-κB signaling pathways

Chemokines and adhesion molecules are major inflammatory mediators of chronic and recurrent vernal keratoconjunctivitis (VKC). Sulforaphane (SFN) is a natural plant extract that is known to have anti-inflammatory and antioxidant properties. SFN is demonstrated to be effective against a variety of human diseases. The current investigation examines the effects and the molecular mechanisms of SFN on cytokine-induced human corneal fibroblasts (HCFs) expression of adhesion molecules and chemokines. HCFs were exposed to both interleukin (IL)-4 and tumor necrosis factor (TNF)-α in the absence or presence of SFN treatment. The levels of thymus- and activation-regulated chemokine (TARC) and eotaxin-1 in culture supernatants were evaluated using enzyme-linked immunosorbent assay (ELISA). Reverse transcription-polymerase chain reaction analysis (RT-PCR) enabled quantification of mRNA levels of vascular cell adhesion molecule (VCAM)-1, eotaxin-1, and TARC along with cytokine receptors. An immunoblotting assay was used to evaluate the activities of VCAM-1, nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), signal transducer and activator of transcription factor (STAT)6 pathways, along with the expression of the cytokine receptors including IL-4 receptor (R)α, IL-13Rα1, TNFRI, as well as TNFRII. SFN inhibited TARC and eotaxin-1 release in HCFs stimulated by TNF-α and IL-4 in a manner dependent on dose and time. SFN suppressed transcriptions of TARC, eotaxin-1, and VCAM-1. Furthermore, the mRNA and protein expression levels of IL-4Rα, TNFRI, and TNFRII were also attenuated by SFN exposure, however, those of IL-13Rα1 remained unaffected. In addition, SFN downregulated the expression of VCAM-1 and the phosphorylation of MAPKs, IκBα, and STAT6. These results suggest that SFN inhibited cytokine-stimulated TARC, eotaxin-1 secretion as well as VCAM-1 expression in HCFs, with these effects likely occurring as a result of cytokine receptor inhibition and attenuation of MAPK, NF-κB, and STAT6 signaling. SFN may therefore have therapeutic potential in VKC treatment.

Translational targeting of inflammation and fibrosis in frozen shoulder: Molecular dissection of the T cell/IL-17A axis

Frozen shoulder is a common fibroproliferative disease characterized by the insidious onset of pain and restricted range of shoulder movement with a significant socioeconomic impact. The pathophysiological mechanisms responsible for chronic inflammation and matrix remodeling in this prevalent fibrotic disorder remain unclear; however, increasing evidence implicates dysregulated immunobiology. IL-17A is a key cytokine associated with inflammation and tissue remodeling in numerous musculoskeletal diseases, and thus, we sought to determine the role of IL-17A in the immunopathogenesis of frozen shoulder. We demonstrate an immune cell landscape that switches from a predominantly macrophage population in nondiseased tissue to a T cell-rich environment in disease. Furthermore, we observed a subpopulation of IL-17A-producing T cells capable of inducing profibrotic and inflammatory responses in diseased fibroblasts through enhanced expression of the signaling receptor IL-17RA, rendering diseased cells more sensitive to IL-17A. We further established that the effects of IL-17A on diseased fibroblasts was TRAF-6/NF-κB dependent and could be inhibited by treatment with an IKKβ inhibitor or anti-IL-17A antibody. Accordingly, targeting of the IL-17A pathway may provide future therapeutic approaches to the management of this common, debilitating disease.

Promising Biomarkers of Radiation-Induced Lung Injury: A Review

Radiation-induced lung injury (RILI) is one of the main dose-limiting side effects in patients with thoracic cancer during radiotherapy. No reliable predictors or accurate risk models are currently available in clinical practice. Severe radiation pneumonitis (RP) or pulmonary fibrosis (PF) will reduce the quality of life, even when the anti-tumor treatment is effective for patients. Thus, precise prediction and early diagnosis of lung toxicity are critical to overcome this longstanding problem. This review summarizes the primary mechanisms and preclinical animal models of RILI reported in recent decades, and analyzes the most promising biomarkers for the early detection of lung complications. In general, ideal integrated models considering individual genetic susceptibility, clinical background parameters, and biological variations are encouraged to be built up, and more prospective investigations are still required to disclose the molecular mechanisms of RILI as well as to discover valuable intervention strategies.

IgG4-related disease and idiopathic multicentric Castleman's disease: confusable immune-mediated disorders

IgG4-related disease (IgG4-RD) and idiopathic multicentric Castleman's disease (iMCD) are both rare systemic immune-mediated disorders. However, pathogenesis differs markedly between the two diseases, and differing therapeutic strategies are adopted: IgG4-RD is treated using a moderate dose of glucocorticoids or rituximab, while iMCD therapy involves an interleukin (IL)-6 targeted approach. Nonetheless, some clinical features of IgG4-RD and iMCD overlap, so differential diagnosis is sometimes difficult, even though the classification and diagnostic criteria of the diseases require careful exclusion of the other. The key findings in IgG4-RD are high IgG4/IgG ratio, allergic features, and germinal centre expansion involving T follicular helper cells, while iMCD involves polyclonal antibody production (high IgA and IgM levels), sheet-like mature plasma cell proliferation, and inflammatory features driven by IL-6. The distribution of organ involvement also provides important clues in both diseases. Particular attention should be given to differential diagnosis using combined clinical and/or pathological findings, because single features cannot distinguish IgG4-RD from iMCD. In the present review, we discuss the similarities and differences between IgG4-RD and iMCD, as well as how to distinguish the two diseases.

IL-13 deficiency exacerbates lung damage and impairs epithelial-derived type 2 molecules during nematode infection

IL-13 is implicated in effective repair after acute lung injury and the pathogenesis of chronic diseases such as allergic asthma. Both these processes involve matrix remodelling, but understanding the specific contribution of IL-13 has been challenging because IL-13 shares receptors and signalling pathways with IL-4. Here, we used Nippostrongylus brasiliensis infection as a model of acute lung damage comparing responses between WT and IL-13-deficient mice, in which IL-4 signalling is intact. We found that IL-13 played a critical role in limiting tissue injury and haemorrhaging in the lung, and through proteomic and transcriptomic profiling, identified IL-13-dependent changes in matrix and associated regulators. We further showed a requirement for IL-13 in the induction of epithelial-derived type 2 effector molecules such as RELM-α and surfactant protein D. Pathway analyses predicted that IL-13 induced cellular stress responses and regulated lung epithelial cell differentiation by suppression of Foxa2 pathways. Thus, in the context of acute lung damage, IL-13 has tissue-protective functions and regulates epithelial cell responses during type 2 immunity.

Beneficial impact of cathelicidin on hypersensitivity pneumonitis treatment-In vivo studies

Cathelicidin (CRAMP) is a defence peptide with a wide range of biological responses including antimicrobial, immunomodulatory and wound healing. Due to its original properties the usefulness of CRAMP in the treatment of pulmonary fibrosis was assessed in a murine model of hypersensitivity pneumonitis (HP). The studies were conducted on mouse strain C57BL/6J exposed to a saline extract of Pantoea agglomerans cells (HP inducer). Cathelicidin was administered in the form of an aerosol during and after HP development. Changes in the composition of immune cell populations (NK cells, macrophages, lymphocytes: Tc, Th, Treg, B), were monitored in lung tissue by flow cytometry. Extracellular matrix deposition (collagens, hydroxyproline), the concentration of cytokines involved in inflammatory and the fibrosis process (IFNγ, TNFα, TGFβ1, IL1β, IL4, IL5, IL10, IL12α, IL13) were examined in lung homogenates by the ELISA method. Alterations in lung tissue morphology were examined in mouse lung sections stained with haematoxylin and eosin as well as Masson trichrome dyes. The performed studies revealed that cathelicidin did not cause any negative changes in lung morphology/structure, immune cell composition or cytokines production. At the same time, CRAMP attenuated the immune reaction induced by mice chronic exposure to P. agglomerans and inhibited hydroxyproline and collagen deposition in the lung tissue of mice treated with bacteria extract. The beneficial effect of CRAMP on HP treatment was associated with restoring the balance in quantity of immune cells, cytokines production and synthesis of extracellular matrix components. The presented study suggests the usefulness of cathelicidin in preventing lung fibrosis; however, cathelicidin was not able to reverse pathological changes completely.

Polymorphisms of interleukin 4 and interleukin 4 receptor genes and bronchial asthma risk among Egyptian children

BACKGROUND

Interleukin 4 (IL4) is a key cytokine that regulates the inflammatory cascade in bronchial asthma. We investigated the association between the IL4 and IL4R polymorphisms and the susceptibility for bronchial asthma among Egyptian children.

METHODS

IL4 VNTR and IL4R c.1902 A>G p.(Q576R) polymorphisms were investigated among 100 children with bronchial asthma and 100 healthy controls using PCR method. Serum levels of IL4 and immunoglobulin E (IgE) were assessed by ELISA.

RESULTS

The frequencies of (A1A2 + A2A2) genotypes and A2-allele of the IL4 VNTR variant were significantly higher among asthmatic patients than controls (p = 0.01, OR = 2.34, 95% CI = 1.24-4.44; p = 0.01, OR = 2.27, 95% CI = 1.29-3.99, respectively). The frequencies of (AG + GG) genotypes and G-allele of the IL4R (A1902G) variant were significantly higher among asthmatic patients than controls (p = 0.003, OR = 2.52, 95% CI = 1.39-4.58; p = 0.002, OR = 2.25, 95% CI = 1.35-3.76, respectively). There was a significant association between (A1A2 + A2A2) genotypes of the IL4 VNTR variant and high serum IL4 level among asthmatic patients (p < 0.001). The (AG + GG) genotypes of the IL4R (A1902G) variant were significantly associated with exposure to triggers, atopic dermatitis and higher serum IgE level in asthmatic patients (p = 0.02, 0.04 and 0.01, respectively).

CONCLUSION

IL4 VNTR and IL4R (A1902G) polymorphisms could be associated with higher risks of bronchial asthma among Egyptian children.

Phase 2 trial to assess lebrikizumab in patients with idiopathic pulmonary fibrosis

This phase 2, randomised, double-blind, placebo-controlled trial evaluated the efficacy and safety of lebrikizumab, an interleukin (IL)-13 monoclonal antibody, alone or with background pirfenidone therapy, in patients with idiopathic pulmonary fibrosis (IPF).

Patients with IPF aged ≥40 years with forced vital capacity (FVC) of 40%–100% predicted and diffusing capacity for carbon monoxide of 25%–90% predicted and who were treatment-naïve (cohort A) or receiving pirfenidone (2403 mg·day⁻¹; cohort B) were randomised 1:1 to receive lebrikizumab 250 mg or placebo subcutaneously every 4 weeks. The primary endpoint was annualised rate of FVC % predicted decline over 52 weeks.

In cohort A, 154 patients were randomised to receive lebrikizumab (n=78) or placebo (n=76). In cohort B, 351 patients receiving pirfenidone were randomised to receive lebrikizumab (n=174) or placebo (n=177). Baseline demographics were balanced across treatment arms in both cohorts. The primary endpoint (annualised rate of FVC % predicted decline) was not met in cohort A (lebrikizumab versus placebo, −5.2% versus −6.2%; p=0.456) or cohort B (lebrikizumab versus placebo, −5.5% versus −6.0%; p=0.557). In cohort B, a non-statistically significant imbalance in mortality favouring combination therapy was observed (hazard ratio 0.42 (95% CI 0.17–1.04)). Pharmacodynamic biomarkers indicated lebrikizumab activity. The safety profile was consistent with that in previous studies of lebrikizumab and pirfenidone as monotherapies.

Lebrikizumab alone or with pirfenidone was not associated with reduced FVC % predicted decline over 52 weeks despite evidence of pharmacodynamic activity. Lebrikizumab was well tolerated with a favourable safety profile. These findings suggest that blocking IL-13 may not be sufficient to achieve a lung function benefit in patients with IPF.

This phase 2 RCT found no benefit in FVC decline over 52 weeks in IPF patients for lebrikizumab versus placebo as monotherapy (n=78 versus 76) or in combination with pirfenidone (n=174 versus 177); pirfenidone therapy was consistent with previous resultshttps://bit.ly/313NVR8

Regulation of extracellular matrix assembly and structure by hybrid M1/M2 macrophages

Aberrant extracellular matrix (ECM) assembly surrounding implanted biomaterials is the hallmark of the foreign body response, in which implants become encapsulated in thick fibrous tissue that prevents their proper function. While macrophages are known regulators of fibroblast behavior, how their phenotype influences ECM assembly and the progression of the foreign body response is poorly understood. In this study, we used in vitro models with physiologically relevant macrophage phenotypes, as well as controlled release of macrophage-modulating cytokines from gelatin hydrogels implanted subcutaneously in vivo to investigate the role of macrophages in ECM assembly. Primary human macrophages were polarized to four distinct phenotypes, which have each been associated with fibrosis, including pro-inflammatory M1, pro-healing M2, and a hybrid M1/M2, generated by exposing macrophages to M1-and M2-promoting stimuli simultaneously. Additionally, macrophages were first polarized to M1 and then to M2 (M1→M2) to generate a phenotype typically observed during normal wound healing. Human dermal fibroblasts that were cultured in macrophage-conditioned media upregulated numerous genes involved in regulation of ECM assembly, especially in M2-conditioned media. Hybrid M1/M2 macrophage-conditioned media caused fibroblasts to produce a matrix with thicker and less aligned fibers, while M2 macrophage-conditioned media caused the formation of a more aligned matrix with thinner fibers. Gelatin methacrylate hydrogels containing interleukin-4 (IL4) and IL13-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were designed to promote the M2 phenotype in a murine subcutaneous in vivo model. NanoString multiplex gene expression analysis of hydrogel explants showed that hydrogels without cytokines caused mostly M1 phenotype markers to be highly expressed at an early time point (3 days), but the release of IL4+IL13 promoted upregulation of M2 markers and genes associated with regulation of ECM assembly, such as Col5a1 and Col6a1. Biochemical analysis and second harmonic generation microscopy showed that the release of IL4+IL13 increased total sulfated glycosaminoglycan content and decreased fibril alignment, which is typically associated with less fibrotic tissue. Together, these results show that hybrid M1/M2 macrophages regulate ECM assembly, and that shifting the balance towards M2 may promote architectural and compositional changes in ECM with enhanced potential for downstream remodeling.

Hesperetin attenuates silica-induced lung injury by reducing oxidative damage and inflammatory response

Oxidative stress and the inflammatory response are two important mechanisms of silica-induced lung injury. Hesperetin (HSP) is a natural flavonoid compound that is found in citrus fruits and has been indicated to exhibit strong antioxidant and anti-inflammatory properties. The current study evaluated the protective effect of HSP on lung injury in rats exposed to silica. The results indicated that the degree of alveolitis and pulmonary fibrosis in the HSP-treated group was significantly decreased compared with the silica model group. The content of hydroxyproline (HYP) was also revealed to decrease overall in the HSP treated group compared with the silica model group, indicating that the degree of pulmonary fibrosis was decreased compared with the silica model group. The present study also demonstrated that HSP reduced oxidation levels of malondialdehyde (MDA) and increased the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX). Total antioxidant capacity (T-AOC) was also increased following HSP treatment, indicating that HSP can alleviate oxidative stress in the lung tissue of silica-exposed rats. In addition, HSP was revealed to inhibit the synthesis and secretion of fibrogenic factor TGF-β1, reduce the production of pro-inflammatory cytokines IL-1β, IL-4, TNF-α and increase the levels of anti-inflammatory factors IFN-γ and IL-10. The current study demonstrated that HSP can effectively attenuate silica-induced lung injury by reducing oxidative damage and the inflammatory response.

Structure and function of small airways in asthma patients revisited

Small airways (<2 mm in diameter) are probably involved across almost all asthma severities and they show proportionally more structural and functional abnormalities with increasing asthma severity. The structural and functional alterations of the epithelium, extracellular matrix and airway smooth muscle in small airways of people with asthma have been described over many years using in vitro studies, animal models or imaging and modelling methods. The purpose of this review was to provide an overview of these observations and to outline several potential pathophysiological mechanisms regarding the role of small airways in asthma.

Maternal high-fat diet activates hepatic interleukin-4 in rat male offspring accompanied by increased eosinophil infiltration

Interleukin-4 (IL-4) is activated as an immune response during infection or tissue injury. Epigenetic programming of maternal high-fat (HF) diet has long-term effects in the offspring. In the present study, we investigated the epigenetic regulation of IL-4 in a maternal HF diet model in the liver of adult offspring. Timed-pregnant Sprague-Dawley rats were fed either control (C) or HF diet throughout gestation and lactation. Offspring were placed on a control diet after weaning, generating C/C and HF/C groups. The liver was collected at 12 wk of age, followed by histological and molecular analysis to investigate the maternal programming effects on IL-4 by HF diet. Maternal HF diet significantly induced mRNA expression and protein level of IL-4 and promoted hypomethylation of Il4 compared with the control group. Methylation-selective PCR (MSP) confirmed that maternal HF diet increased RNA polymerase II, acetylation of histone H4, and dimethylation of histone 3 lysine 4 at the +6 kb region of Il4. Moreover, the rat eosinophil marker Siglec-F was increased and colocalized with IL-4 in the liver. In conclusion, our study indicated that IL-4 was increased in liver cells in response to maternal HF diet. This coincides with DNA hypomethylation in combination with chromatin remodeling at the +6 kb region of the 3' downstream region as well as an induced immune cell infiltration, especially eosinophil infiltration, in the liver of offspring.NEW & NOTEWORTHY The present study identifies that maternal high-fat-diet-induced IL-4 upregulation is associated with DNA hypomethylation at the +6 kb region of the 3' downstream region of the gene. Furthermore, our results confirm that the induced Il4 expression in the liver of male offspring corresponds to the induced immune cell, especially eosinophil, infiltration.

The regulatory role of SFRP5/WNT5A axis in allergic rhinitis through inhibiting JNK pathway activation and lowering mucin generation in human nasal epithelial cells

Allergic rhinitis (AR) is tightly associated with type 2 inflammation. SFRP5 combined with WNT5A mainly inhibits chronic inflammatory response, atherosclerosis, and other metabolic disorders. However, the effect of SFRP5/WNT5A axis on recombinant human interleukin-13 (rhIL-13)-induced inflammation has not been studied. In this study, we aimed to investigate whether secreted frizzled-related protein 5 (SFRP5) could modulate the production of cytokines relevant to eosinophil infiltration and mucin secretion through blocking the activation of Wnt family 5A (WNT5A) signaling pathway. A mouse model of AR demonstrated low expression of SFRP5 and high expression of WNT5A, and indicated that the number of eosinophil and goblet cells was increased, concomitant with elevated IL-13, colony stimulating factor 2 (CSF2), chemokine ligand 11 (CCL11), Mucin 4, and Mucin 5AC levels. Furthermore, lentivirus-SFRP5 overexpression up-regulated the expression of SFRP5 but down-regulated WNT5A level, and inhibited the activation of JNK pathway via decreasing p-JNK1/2 (Thr183/Tyr185) and p-c-Jun (Ser73) protein expressions in rhIL-13-treated human nasal epithelial cells (HNEpCs). Noticeably, SFRP5 overexpression markedly reduced rhIL-13-induced inflammatory protein and mucin generation through lowered CSF2, CCL11, Mucin 4, as well as Mucin 5AC levels. Taken together, these findings confirmed the regulatory role of SFRP5/WNT5A axis in rhIL-13-mediated inflammatory response in HNEpCs.

Circulating fibrocytes as prognostic biomarkers of autoimmune interstitial lung disease

Background

Autoimmunity is a common cause of pulmonary fibrosis and can present either as a manifestation of an established connective tissue disease or as the recently described entity of interstitial pneumonia with autoimmune features. The rate of progression and responsiveness to immunosuppression in these illnesses are difficult to predict. Circulating fibrocytes are bone marrow-derived progenitor cells that home to injured tissues and contribute to lung fibrogenesis. We sought to test the hypothesis that the blood fibrocyte concentration predicts outcome and treatment responsiveness in autoimmune interstitial lung diseases.

Methods

We compared the concentration of circulating fibrocytes in 50 subjects with autoimmune interstitial lung disease and 26 matched healthy controls and assessed the relationship between serial peripheral blood fibrocyte concentrations and clinical outcomes over a median of 6.25 years.

Results

As compared to controls, subjects with autoimmune interstitial lung disease had higher circulating concentrations of total fibrocytes, the subset of activated fibrocytes, and fibrocytes with activation of PI3K/AKT/mTOR, transforming growth factor-β (TGF-β) receptor and interleukin (IL)-4/IL-13 receptor signalling pathways. Over the follow-up period, there were episodes of marked elevation in the concentration of circulating fibrocytes in subjects with autoimmune interstitial lung disease but not controls. Initiation of immunosuppressive therapy was associated with a decline in the concentration of circulating fibrocytes. For each 100 000 cells·mL⁻¹ increase in peak concentration of circulating fibrocytes, we found a 5% increase in odds of death or lung function decline.

Conclusion

In patients with autoimmune interstitial lung disease, circulating fibrocytes may represent a biomarker of outcome and treatment response.

Autoimmune diseases are common causes of pulmonary fibrosis. The blood concentration of fibrocytes, cells involved in formation of scar tissue, predicts outcomes and response to immunosuppression in these patients.https://bit.ly/35bel62

Emerging concepts and directed therapeutics for the management of asthma: regulating the regulators

Asthma is a common, heterogeneous and serious disease, its prevalence has steadily risen in most parts of the world, and the condition is often inadequately controlled in many patients. Hence, there is a major need for new therapeutic approaches. Mild-to-moderate asthma is considered a T-helper cell type-2-mediated inflammatory disorder that develops due to abnormal immune responses to otherwise innocuous allergens. Prolonged exposure to allergens and persistent inflammation results in myofibroblast infiltration and airway remodelling with mucus hypersecretion, airway smooth muscle hypertrophy, and excess collagen deposition. The airways become hyper-responsive to provocation resulting in the characteristic wheezing and obstructed airflow experienced by patients. Extensive research has progressed the understanding of the underlying mechanisms and the development of new treatments for the management of asthma. Here, we review the basis of the disease, covering new areas such as the role of vascularisation and microRNAs, as well as associated potential therapeutic interventions utilising reports from animal and human studies. We also cover novel drug delivery strategies that are being developed to enhance therapeutic efficacy and patient compliance. Potential avenues to explore to improve the future of asthma management are highlighted.

Kathon Induces Fibrotic Inflammation in Lungs: The First Animal Study Revealing a Causal Relationship between Humidifier Disinfectant Exposure and Eosinophil and Th2-Mediated Fibrosis Induction

Currently available toxicity data on humidifier disinfectants are primarily limited to polyhexamethylene guanidine phosphate-induced lung fibrosis. We, therefore, investigated whether the sterilizer component Kathon, which is a mixture of chloromethylisothiazolinone and methylisothiazolinone, induces fibrotic lung injury following direct lung exposure in an animal model. Mice were intratracheally instilled with either the vehicle or Kathon. Differential cell counts, cytokine analysis, and histological analysis of lung tissue were then performed to characterize the injury features, and we investigated whether Kathon altered fibrosis-related gene expression in lung tissues via RNA-Seq and bioinformatics. Cell counting showed that Kathon exposure increased the proportion of macrophages, eosinophils, and neutrophils. Moreover, T helper 2 (Th2) cytokine levels in the bronchoalveolar lavage were significantly increased in the Kathon groups. Histopathological analysis revealed increased perivascular/alveolar inflammation, eosinophilic cells, mucous cell hyperplasia, and pulmonary fibrosis following Kathon exposure. Additionally, Kathon exposure modulated the expression of genes related to fibrotic inflammation, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, extracellular signal regulated kinase (ERK)1 and ERK2 cascade, extracellular matrix (ECM)-receptor interaction pathway, transforming growth factor beta receptor signaling pathway, cellular response to tumor necrosis factor, and collagen fibril organization. Our results suggest that Kathon exposure is associated with fibrotic lung injury via a Th2-dependent pathway and is thus a possible risk factor for fibrosis.

Modulation of Cytokines and Extracellular Matrix Proteins Expression by Leishmania amazonensis in Susceptible and Resistant Mice

Leishmaniases are a complex of diseases with a broad spectrum of clinical forms, which depend on the parasite species, immunological status, and genetic background of the host. In the Leishmania major model, susceptibility is associated with the Th2 pattern of cytokines production, while resistance is associated with Th1 response. However, the same dichotomy does not occur in L. amazonensis-infected mice. Cytokines are key players in these diseases progression, while the extracellular matrix (ECM) components participate in the process of parasite invasion as well as lesion healing. In this article, we analyzed the influence of host genetics on the expression of cytokines, inducible nitric oxide synthase (iNOS), and ECM proteins, as well as the parasite load in mice with different genetic backgrounds infected by L. amazonensis. C57BL/10 and C3H/He mice were subcutaneously infected with 10⁶L. amazonensis promastigotes. Lesion kinetics, parasite load, cytokines, iNOS, and ECM proteins expression were measured by quantitative PCR (qPCR) in the footpad, draining lymph nodes, liver, and spleen at early (24 h and 30 days) and late phase (120 and 180 days) of infection. Analysis of lesion kinetics showed that C57BL/10 mice developed ulcerative lesions at the inoculation site after L. amazonensis infection, while C3H/He showed slight swelling in the footpad 180 days after infection. C57BL/10 showed progressive enhancement of parasite load in all analyzed organs, while C3H/He mice showed extremely low parasite loads. Susceptible C57BL/10 mice showed high levels of TGF-β mRNA in the footpad early in infection and high levels of proinflammatory cytokines mRNA (IL-12, TNF-α, and IFN-γ) and iNOS in the late phase of the infection. There is an association between increased expression of fibronectin, laminin, collagen III and IV, and TGF-β. On the other hand, resistant C3H/He mice presented a lower repertory of cytokines mRNA expression when compared with susceptible C57BL/10 mice, basically producing TNF-α, collagen IV, and laminin early in infection. The findings of our study indicate that L. amazonensis infection induces different cytokine expression in resistant and susceptible mice but not like the L. major model. An organ-compartmentalized cytokine response was observed in our model. Host genetics determine this response, which modulates ECM proteins expression.

Attenuation of Dupuytren's fibrosis via targeting of the STAT1 modulated IL-13Rα1 response

Fibrotic disorders represent common complex disease pathologies that are therapeutically challenging. Inflammation is associated with numerous fibrotic pathogeneses; however, its role in the multifaceted mechanisms of fibrosis remains unclear. IL-13 is implicated in aberrant responses involved in fibrotic disease, and we aimed to understand its role in the inflammatory processes of a common fibrotic disorder, Dupuytren's disease. We demonstrated T-cells produced IFN-g, which induced IL-13 secretion from mast cells and up-regulated IL-13Ra1 on fibroblasts, rendering them more reactive to IL-13. Consequently, diseased myofibroblasts demonstrated enhanced fibroproliferative effects upon IL-13 stimulation. We established IFN-g and IL-13 responses involved STAT dependent pathways, and STAT targeting (tofacitinib) could inhibit IL-13 production from mast cells, IL-13Ra1 up-regulation in fibroblasts and fibroproliferative effects of IL-13 on diseased myofibroblasts. Accordingly, utilizing Dupuytren's as an accessible human model of fibrosis, we propose targeting STAT pathways may offer previously unidentified therapeutic approaches in the management of fibrotic disease.

Radiation-Induced Lung Fibrosis: Preclinical Animal Models and Therapeutic Strategies

Radiation-induced lung injury (RILI), including acute radiation pneumonitis and chronic radiation-induced lung fibrosis, is the most common side effect of radiation therapy. RILI is a complicated process that causes the accumulation, proliferation, and differentiation of fibroblasts and, finally, results in excessive extracellular matrix deposition. Currently, there are no approved treatment options for patients with radiation-induced pulmonary fibrosis (RIPF) partly due to the absence of effective targets. Current research advances include the development of small animal models reflecting modern radiotherapy, an understanding of the molecular basis of RIPF, and the identification of candidate drugs for prevention and treatment. Insights provided by this research have resulted in increased interest in disease progression and prognosis, the development of novel anti-fibrotic agents, and a more targeted approach to the treatment of RIPF.

Evaluation serum levels of YKL-40, Periostin, and some inflammatory cytokines together with IL-37, a new anti-inflammatory cytokine, in patients with stable and exacerbated asthma

INTRODUCTION

As asthma has a wide range of inflammatory pathways, the researchers were focused on the markers that may be associated with exacerbation and stability in asthma.

OBJECTIVE

Our aim is to investigate the serum levels of some inflammatory markers and cytokines in stable and exacerbated asthmatic patients.

METHODS

The study included in 59 non-smoker asthma patient (Exacerbated=25, Stable=34) and 30 healthy volunteers. The serum level of periostin, YKL-40, IL-4, IL-5, IL-37, and TNF-α were detected by enzyme-linked immunosorbent assay.

RESULTS

Except for IL-37, the periostin, YKL-40, IL-4, IL-5, and TNF-α level in asthmatic patients were significantly higher than those of healthy control. In the exacerbated group, the periostin, YKL-40, IL-5, and TNF-α level were significantly higher than stable asthma and healthy control groups. The serum levels of IL-4 in exacerbated and stable asthma groups were significantly higher than healthy control group. There was a significant difference between IL4 levels, in stable asthma and healthy control groups. In exacerbated asthma group, IL-37 level was significantly lower than stable and healthy control groups. The highest area under the ROC curve (AUC) was found for IL-4. While there was a significant negative correlation between these parameters and FEV1, there was a positive correlation between IL-37 and FEV1, but not significant.

CONCLUSIONS

This study showed that increased serum periostin, YKL-40, IL-5, IL-4, and TNF-α and decreased serum IL-37 were associated with exacerbation showing uncontrolled asthma.

TGFβ1 mimetic peptide modulates immune response to grass pollen allergens in mice

Background

Transforming growth factor β1 (TGFβ1) is a cytokine that exerts immunosuppressive functions, as reflected by its ability to induce regulatory T (Treg) cell differentiation and inhibit Th1 and Th2 responses. Hence, peptides that mimic the active core domain of TGFβ1 may be promising candidates for modulation of the allergic response. This study aimed to investigate a synthetic TGFβ1 mimetic peptide (TGFβ1‐mim) for its ability to modulate the immune response during allergic sensitization to grass pollen allergens.

Methods

The in vitro action of TGFβ1‐mim was evaluated in human lung epithelial cells, Jurkat cells, and rat basophilic leukemia cells. The in vivo action was evaluated in a murine model of Phl p 5 allergic sensitization. Additionally, the Th2 modulatory response was evaluated in IL‐4 reporter mice.

Results

In vitro, TGFβ1‐mim downregulated TNF‐α production, IL‐8 gene expression, and cytokine secretion, upregulated IL‐10 secretion, and inhibited Phl p 5‐induced basophil degranulation. During Phl p 5 sensitization in mice, TGFβ1‐mim downregulated IL‐2, IL‐4, IL‐5, IL‐13, and IFN‐γ, upregulated IL‐10, and induced Treg cell production. Furthermore, mice treated with TGFβ1‐mim had lower levels of IgE, IgG1, IgG2a and higher levels of IgA antibodies than control mice. In a reporter mouse, the mimetic inhibited Th2 polarization.

Conclusion

The TGFβ1‐mim efficiently modulated various important events that exacerbate the allergic microenvironment, including the production of main cytokines that promote Th1 and Th2 differentiation, and the induction of allergen‐specific regulatory T cells, highlighting its potential use in therapeutic approaches to modulate the immune response toward environmental allergens.

IL-4 controls activated neutrophil FcγR2b expression and migration into inflamed joints

Neutrophils are the most abundant immune cells found in actively inflamed joints of patients with rheumatoid arthritis (RA), and most animal models for RA depend on neutrophils for the induction of joint inflammation. Exogenous IL-4 and IL-13 protect mice from antibody-mediated joint inflammation, although the mechanism is not understood. Neutrophils display a very strong basal expression of STAT6, which is responsible for signaling following exposure to IL-4 and IL-13. Still, the role of IL-4 and IL-13 in neutrophil biology has not been well studied. This can be explained by the low neutrophil surface expression of the IL-4 receptor α-chain (IL-4Rα), essential for IL-4- and IL-13-induced STAT6 signaling. Here we identify that colony stimulating factor 3 (CSF3), released during acute inflammation, mediates potent STAT3-dependent neutrophil IL-4Rα up-regulation during sterile inflammatory conditions. We further demonstrate that IL-4 limits neutrophil migration to inflamed joints, and that CSF3 combined with IL-4 or IL-13 results in a prominent neutrophil up-regulation of the inhibitory Fcγ receptor (FcγR2b). Taking these data together, we demonstrate that the IL-4 and CSF3 pathways are linked and play important roles in regulating proinflammatory neutrophil behavior.

Transcriptional regulation of the IL-13Rα2 gene in human lung fibroblasts

Interleukin (IL)-13 is a type 2 cytokine with important roles in allergic diseases, asthma, and tissue fibrosis. Its receptor (R) α1 is primarily responsible for the biological actions of this cytokine, while Rα2 possesses a decoy function which can block IL-13 signaling. Although the expression of Rα2 is known to be subject to modulation, information about its transcriptional regulation is limited. In this study, we sought to expand the understanding of transcriptional control of Rα2 in lung fibroblasts. We confirmed previous reports that IL-13 elicited modest induction of Rα2 in normal adult human lung fibroblasts, but found that prostaglandin E2 (PGE2) and fibroblast growth factor 2 (FGF-2) -mediators known to influence fibroblast activation in tissue fibrosis but not previously investigated in this regard - led to a much greater magnitude of Rα2 induction. Although both PGE2 (via protein kinase A) and FGF-2 (via protein kinase B, also known as AKT) depended on activation of cAMP-responsive element-binding protein (CREB) for induction of Rα2 expression, they nevertheless demonstrated synergy in doing so, likely attributable to their differential utilization of distinct transcriptional start sites on the Rα2 promoter. Our data identify CREB activation via PGE2 and FGF-2 as a previously unrecognized molecular controller of Rα2 gene induction and provide potential new insights into strategies for therapeutic manipulation of this endogenous brake on IL-13 signaling.

Interleukin-13 disrupts type 2 pneumocyte stem cell activity

The T helper 2 (Th2) inflammatory cytokine interleukin-13 (IL-13) has been associated with both obstructive and fibrotic lung diseases; however, its specific effect on the epithelial stem cells in the gas exchange compartment of the lung (alveolar space) has not been explored. Here, we used in vivo lung models of homeostasis and repair, ex vivo organoid platforms, and potentially novel quantitative proteomic techniques to show that IL-13 disrupts the self-renewal and differentiation of both murine and human type 2 alveolar epithelial cells (AEC2s). Significantly, we find that IL-13 promotes ectopic expression of markers typically associated with bronchiolar airway cells and commonly seen in the alveolar region of lung tissue from patients with idiopathic pulmonary fibrosis. Furthermore, we identify a number of proteins that are differentially secreted by AEC2s in response to IL-13 and may provide biomarkers to identify subsets of patients with pulmonary disease driven by "Th2-high" biology.

Targeting interleukin 4 receptor α: A new approach to the treatment of cutaneous autoimmune bullous diseases?

Bullous pemphigoid, mucous membrane pemphigoid, and pemphigus vulgaris are different cutaneous autoimmune blistering diseases, with complex pathogenic mechanisms. In all of them, a type-2 response is thought to have a central role. Interleukin 4 and Interleukin 13 are crucial cytokines in type-2 response. Treatment of these conditions is often challenging. Dupilumab, a recombinant fully human IgG4 monoclonal antibody with binding specificity to human interleukin-4 receptor IL-4Rα, has the potential to inhibit both IL-4 and IL-13. We propose IL-4Rα as a theoretical drug target for cutaneous autoimmune bullous diseases.

The Intriguing Role of Interleukin 13 in the Pathophysiology of Asthma

Approximately 5–10% of asthmatic patients worldwide suffer from severe asthma. Experimental and clinical studies have demonstrated that IL-13 is an important cytokine in chronic airways inflammation. IL-13 is involved in Th2 inflammation and has been identified as a possible therapeutic target in the treatment of asthma. Two different human monoclonal antibodies (mAbs) anti-IL-13 (tralokinumab and lebrikizumab) block binding and signaling of IL-13 to its receptors, IL-13Rα1 and IL-13Rα2. Several randomized, double-blind, placebo-controlled multicenter studies have evaluated the safety and efficacy of tralokinumab and lebrikizumab in the treatment of adult patients with severe asthma, but all have failed to meet their primary endpoints. No serious adverse events related to the treatment with these anti-IL-13 mAbs have been reported in these studies. These negative clinical results contrast with positive findings from blocking IL-13 signaling in experimental models of asthma, raising doubts about the transferrable value of some models. Interestingly, dupilumab, a mAb which blocks both IL-4 and IL-13 signaling reduces exacerbation rates and improves lung function in severe asthmatics. These results suggest that IL-4 and IL-13 share some, but not all functional activities in airway inflammation. Tralokinumab might show efficacy in a highly selected cohort of asthmatics characterized by overexpression of IL-13.

Novel Biological Therapies in Severe Asthma: Targeting the Right Trait

Asthma is a heterogeneous disease characterized by chronic airway inflammation that results in a wide spectrum of clinical manifestations. Patients with severe asthma represent a substantial share of consumption of healthcare resources and hospitalization. Moreover, these patients are at risk of increased morbidity and mortality. Recently, several phenotypes and endotypes of asthma have been identified. The identification of specific subtypes of asthma is fundamental for optimizing the clinical benefit of novel treatments. Although in most patients the disease can be controlled by some combination of pharmacologic agents, in some 5-10% of patients the disease remains uncontrolled. Several monoclonal antibodies (mAbs) targeting pathogenetic molecules (e.g., IgE, IL-5, IL- 5Rα, IL-4, IL-13, TSLP) are currently available or under development for the treatment of different forms of severe type 2 asthma. The identification of diagnostic and predictive biomarkers (e.g., IgE, blood eosinophil count, FeNO, periostin, etc.) has revolutioned the field of targeted therapy in severe asthma. Monoclonal antibodies targeting Th2-driven inflammation are generally safe in adult patients with moderate-to-severe asthma. The long-term safety of these biologics is a relevant issue that should be addressed. Unfortunately, little is known about non-type 2 asthma. Further studies are needed to identify biomarkers to guide targeted therapies of different forms of non-type 2 asthma.

Role of B7H3/IL-33 Signaling in Pulmonary Fibrosis-induced Profibrogenic Alterations in Bone Marrow

Rationale: The impact of lung insult on the bone marrow (BM) and subsequent disease is unknown.Objectives: To study alterations in the BM in response to lung injury/fibrosis and examine their impact on subsequent lung insult.Methods: BM cells from control or bleomycin-treated donor mice were transplanted into naive mice, which were subsequently evaluated for bleomycin-induced pulmonary fibrosis. In addition, the effect of prior bleomycin treatment on subsequent fibrosis was examined in wild-type and B7H3-knockout mice. Samples from patients with idiopathic pulmonary fibrosis were analyzed for potential clinical relevance of the findings.Measurements and Main Results: Recipient mice transplanted with BM from bleomycin-pretreated donors showed significant exacerbation of subsequent fibrosis with increased B7H3+ cell numbers and a T-helper cell type 2-skewed phenotype. Pretreatment with a minimally fibrogenic/nonfibrogenic dose of bleomycin also caused exacerbation, but not in B7H3-deficient mice. Exacerbation was not observed if the mice received naive BM cell transplant after the initial bleomycin pretreatment. Soluble B7H3 stimulated BM Ly6Chi monocytic cell expansion in vitro and caused similar expansion in the lung in vivo. Notably, soluble B7H3 was elevated in plasma of patients with idiopathic pulmonary fibrosis and in BAL fluid in those with acute exacerbation. Finally, ST2 deficiency diminished the bleomycin-induced B7H3 and IL-13 upregulation, suggesting a role for type 2 innate lymphoid cells.Conclusions: Pulmonary fibrosis caused significant alterations in BM with expansion and activation of monocytic cells, which enhanced fibrosis when transplanted to naive recipients with potential mediation by a novel role for B7H3 in the pathophysiology of pulmonary fibrosis in both mice and humans.

Efficacy of an Inhaled IL-13 Antibody Fragment in a Model of Chronic Asthma

RATIONALE

IL-13 is an important cytokine implicated in the pathogenesis of allergic asthma and is an attractive target for an inhaled therapeutic.

OBJECTIVE

To investigate the efficacy of CDP7766, a nebulized inhaled anti-IL-13 monoclonal antibody Fab fragment, in a model of allergic asthma in cynomolgus macaques naturally sensitized to Ascaris suum.

METHODS

CDP7766 was nebulized using a vibrating-membrane nebulizer on the basis of eFlow technology. The aerosol generated was analyzed to determine the particle size profile and the biophysical and functional properties of CDP7766. Nebulized CDP7766 (0.1-60 mg/animal, once daily for 5 d) was delivered via the inhaled route.

MEASUREMENTS AND MAIN RESULTS

The investigational eFlow nebulizer used in this study generated a respirable aerosol of CDP7766 with no evidence of degradation, loss of potency, aggregation, or formation of particulates. Inhaled CDP7766 was well tolerated in the model (no adverse effects related to local irritation) and significantly inhibited BAL allergen-induced cytokine and chemokine upregulation (60 mg vs. vehicle: eotaxin-3, P < 0.0008; MIP [macrophage inflammatory protein]-1β, IL-8, IFN-γ, P ≤ 0.01). CDP7766 significantly inhibited the increase in pulmonary resistance stimulated by inhaled allergen, measured 15 minutes and 24 hours after allergen challenge.

CONCLUSION

Inhaled CDP7766 potently inhibited the function of IL-13 generated during the airway response to inhaled allergen in cynomolgus macaques, demonstrating the potential of inhaled anti-IL-13 therapeutics for the treatment of allergic asthma.

Leptin enhances cytokine/chemokine production by normal lung fibroblasts by binding to leptin receptor

BACKGROUND

Obesity is a known risk and exacerbation factor for bronchial asthma. Leptin is an adipokine secreted by adipocytes and enhances energy consumption. Earlier studies have shown that leptin also activates inflammatory cells and structural cells, including airway epithelial cells, thereby exacerbating inflammation. However, little is known about leptin's effect on normal human lung fibroblasts (NHLFs), which are deeply involved in airway remodeling in asthma. This study aimed to elucidate the direct effect of leptin on NHLFs.

METHODS

NHLFs were co-cultured with leptin, and production of cytokines/chemokines was analyzed with real-time PCR and cytometric bead arrays (CBA). Expression of alpha smooth muscle actin (α-SMA) in the lysate of NHLFs stimulated with leptin was assessed by western blotting. Expression of leptin receptor (Ob-R) was analyzed by real-time PCR and flow cytometry. NHLFs were transfected with Ob-R small interference ribonucleic acid (siRNA) by electroporation and used for experiments.

RESULTS

Leptin enhanced production of CCL11/Eotaxin, monocyte chemoattractant protein-1 (CCL2/MCP-1), CXCL8/IL-8, interferon gamma-induced protein 10 (CXCL10/IP-10) and IL-6 by NHLFs at both the protein and messenger ribonucleic acid (mRNA) levels. Leptin also slightly, but significantly, elevated expression of α-SMA. We found robust Ob-R expression on cell surfaces, and transfection with Ob-R siRNA suppressed the enhanced production of CCL11/Eotaxin, CXCL10/IP-10 and IL-6 by leptin, although not completely.

CONCLUSIONS

These findings indicate that leptin may contribute to worsening of asthma in obese patients by enhancing production of inflammatory mediators by binding to Ob-R and accelerating myofibroblast differentiation.

Interleukin 4: Its Role in Hypertension, Atherosclerosis, Valvular, and Nonvalvular Cardiovascular Diseases

Hypertension is one of the major physiological risk factors for cardiovascular diseases, and it affects more than 1 billion adults worldwide, killing 9 million people every year according to World Health Organization. Also, hypertension is associated with increased risk of kidney disease and stroke. Studying the risk factors that contribute to the pathogenesis of hypertension is key to preventing and controlling hypertension. Numerous laboratories around to globe are very active pursuing research studies to delineate the factors, such as the role of immune system, which could contribute to hypertension. There are studies that were conducted on immune-deficient mice for which experimentally induced hypertension has been ameliorated. Thus, there are possibilities that immune reactivity could be associated with the development of certain type of hypertension. Furthermore, interleukin 4 has been associated with the development of pulmonary hypertension, which could lead to right ventricular remodeling. Also, the immune system is involved in valvular and nonvalvular cardiac remodeling. It has been demonstrated that there is a causative relationship between different interleukins and cardiac fibrosis.

Fra-2-expressing macrophages promote lung fibrosis in mice

Idiopathic Pulmonary Fibrosis (IPF) is a deadly disease with limited therapies. Tissue fibrosis is associated with Type 2 immune response, although the causal contribution of immune cells is not defined. The AP-1 transcription factor Fra-2 is upregulated in IPF lung sections and Fra-2 transgenic mice (Fra-2tg) exhibit spontaneous lung fibrosis. Here we show that Bleomycin-induced lung fibrosis is attenuated upon myeloid-inactivation of Fra-2 and aggravated in Fra-2tg bone marrow chimeras. Type VI collagen (ColVI), a Fra-2 transcriptional target, is up-regulated in three lung fibrosis models, and macrophages promote myofibroblast activation in vitro in a ColVI- and Fra-2-dependent manner. Fra-2 or ColVI inactivation does not affect macrophage recruitment and alternative activation, suggesting that Fra-2/ColVI specifically controls the paracrine pro-fibrotic activity of macrophages. Importantly, ColVI knock-out mice (KO) and ColVI-KO bone marrow chimeras are protected from Bleomycin-induced lung fibrosis. Therapeutic administration of a Fra-2/AP-1 inhibitor reduces ColVI expression and ameliorates fibrosis in Fra-2tg mice and in the Bleomycin model. Finally, Fra-2 and ColVI positively correlate in IPF patient samples and co-localize in lung macrophages. Therefore, the Fra-2/ColVI pro-fibrotic axis is a promising biomarker and therapeutic target for lung fibrosis, and possibly other fibrotic diseases.

Relationship between various cytokines implicated in asthma

Asthma is a complex disorder involving immunologic, environmental, genetic and other factors. Today, asthma is the most common disease encountered in clinical medicine in both children and adults worldwide. Asthma is characterized by increased responsiveness of the tracheobronchial tree resulting in chronic swelling and inflammation of the airways recognized to be controlled by the T-helper 2 (Th2) lymphocytes, which secrete cytokines to increase the production of IgE by B cells. There are many cytokines implicated in the development of the chronic inflammatory processes that are often observed in asthma. Ultimately, these cytokines cause the release of mediators such as histamine and leukotrienes (LT), which in turn promote airway remodeling, bronchial hyperresponsiveness and bronchoconstriction. The CD4⁺ T-lymphocytes from the airways of asthmatics express a panel of cytokines that represent the Th2 cells. The knowledge derived from numerous experimental and clinical studies have allowed physicians and scientists to understand the normal functions of these cytokines and their roles in the pathogenesis of asthma. The main focus of this review is to accentuate the relationship between various cytokines implicated in human asthma. However, some key findings from animal models will be highlighted to support the discoveries from clinical studies.

Amelioration of allergic asthma by Ziziphora clinopodioides via upregulation of aquaporins and downregulation of IL4 and IL5

Ziziphora clinopodioides has been frequently used as an anti asthmatic plant in traditional medication. Recent work explores the anti-asthmatic activity of Z. clinopodioides in allergen-induced asthmatic mice. Intraperitoneal sensitization followed by intranasal challenge were given with ovalbumin (allergen) to develop allergic asthma. Investigational groups of animals were administered with drug methylprednisolone (MP) (15 mg/kg body weight), n-hexane fraction, ethylacetate fraction, and methanolic extract of Z. clinopodioides extract (500 mg/kg b.w.) for successive 07 days. Hematoxyline and eosin (H&E) and periodic acid-Schiff (PAS) stains were used to evaluate histopathological parameters on lung tissues. As an index of lungs tissues edema, wet/dry weight ratio of lungs was determined. Evaluation of expression levels of AQP1, AQP5, IL4, and IL5 was conducted by using RT-PCR. The data exhibited that both Z. clinopodioides and MP attenuated differential and total leukocyte counts in hematological examination i.e. in BALF and blood. Treatment with Z. clinopodioides also caused suppression of inflammatory cell infiltration and expression levels of IL4 and IL5, the later could have caused attenuation of pulmonary inflammation. The study also found decline in lung wet/dry ratio and goblet cellh hyperplasia in treated groups which indicates amelioration of lung edema. Treatment with Z. clinopodioides significantly increased the expression levels of aquaporin-1 and -5, which could have led to reduction in lung edema. The treatment with MP showed comparable results to Z. clinopodioides. Current investigation revealed that Z. clinopodioides possessed anti-asthmatic property which might be accredited to upregulagted AQP1 and AQP5 levels and downregulated IL4 and IL5 levels.

The benefits and prospects of interleukin-6 inhibitor on systemic sclerosis

Systemic sclerosis (SSc) is a connective tissue disease, the pathogenesis of which is thought to involve interleukin-6 (IL-6), an inflammatory cytokine. This is based on findings of its concentration in patient serum, the results of an IL-6 suppression experiment in an animal model, and the results of a pilot study using IL-6 receptor antibody. However, it appears that a number of factors are involved in the pathology of SSc depending on the state of disease progression. In addition, the degree of involvement of IL-6 differs depending on the difference of organs within particular severe symptoms. Based on the findings from measurements of patient serum, the influence of IL-6 on the pathogenesis of SSc is greater in patients at a relatively early phase of the disease and in patients with lung lesions. Interleukin-13 (IL-13) is one of pro-fibrotic factors, and it is afraid that SSc patients with higher IL-13 have already lost the influence of IL-6. Therefore, although a clinical trial using the anti-IL-6 receptor antibody tocilizumab is underway, it is important to recognize the state of SSc patients prior to selecting treatment.

The controversial role of mast cells in fibrosis

Fibrosis is a medical condition characterized by an excessive deposition of extracellular matrix compounds such as collagen in tissues. Fibrotic lesions are present in many diseases and can affect all organs. The excessive extracellular matrix accumulation in these conditions can often have serious consequences and in many cases be life-threatening. A typical event seen in many fibrotic conditions is a profound accumulation of mast cells (MCs), suggesting that these cells can contribute to the pathology. Indeed, there is now substantialv evidence pointing to an important role of MCs in fibrotic disease. However, investigations from various clinical settings and different animal models have arrived at partly contradictory conclusions as to how MCs affect fibrosis, with many studies suggesting a detrimental role of MCs whereas others suggest that MCs can be protective. Here, we review the current knowledge of how MCs can affect fibrosis.

Fibroblast-to-myofibroblast transition in bronchial asthma

Bronchial asthma is a chronic inflammatory disease in which bronchial wall remodelling plays a significant role. This phenomenon is related to enhanced proliferation of airway smooth muscle cells, elevated extracellular matrix protein secretion and an increased number of myofibroblasts. Phenotypic fibroblast-to-myofibroblast transition represents one of the primary mechanisms by which myofibroblasts arise in fibrotic lung tissue. Fibroblast-to-myofibroblast transition requires a combination of several types of factors, the most important of which are divided into humoural and mechanical factors, as well as certain extracellular matrix proteins. Despite intensive research on the nature of this process, its underlying mechanisms during bronchial airway wall remodelling in asthma are not yet fully clarified. This review focuses on what is known about the nature of fibroblast-to-myofibroblast transition in asthma. We aim to consider possible mechanisms and conditions that may play an important role in fibroblast-to-myofibroblast transition but have not yet been discussed in this context. Recent studies have shown that some inherent and previously undescribed features of fibroblasts can also play a significant role in fibroblast-to-myofibroblast transition. Differences observed between asthmatic and non-asthmatic bronchial fibroblasts (e.g., response to transforming growth factor β, cell shape, elasticity, and protein expression profile) may have a crucial influence on this phenomenon. An accurate understanding and recognition of all factors affecting fibroblast-to-myofibroblast transition might provide an opportunity to discover efficient methods of counteracting this phenomenon.

TNFSF14 (LIGHT) Exhibits Inflammatory Activities in Lung Fibroblasts Complementary to IL-13 and TGF-β

The cytokine TNFSF14 [homologous to Lymphotoxin, exhibits Inducible expression and competes with HSV Glycoprotein D for binding to HVEM, a receptor expressed on T lymphocytes (LIGHT)] has been shown in mouse models to be important for development of lung tissue remodeling that is characteristic of asthma, idiopathic pulmonary fibrosis (IPF), and systemic sclerosis (SSc). However, its cellular targets are not fully delineated. In the present report, we show that LTβR and HVEM, the receptors for LIGHT, are constitutively expressed in primary human lung fibroblasts (HLFs). We asked whether LIGHT could promote inflammatory and remodeling-relevant activity in HLFs and how this was similar to, or distinct from, IL-13 or TGF-β, two cytokines strongly implicated in the pathogenesis of asthma, IPF, and SSc. Accumulation of myofibroblasts expressing alpha smooth muscle actin is a feature of lung inflammatory diseases. LIGHT promoted cell cycle progression and proliferation of HLFs, but not alpha smooth muscle actin expression. In contrast, TGF-β upregulated alpha smooth muscle actin but did not drive their proliferation. LIGHT also increased the gene or protein expression of a number of proinflammatory mediators, including ICAM-1 and VCAM-1, IL-6 and GM-CSF, the chemokines CCL5 and 20, and CXCL5, 11, and 12, and lung remodeling-associated proteinases MMP-9 and ADAM8. These were dependent on LTβR but not HVEM. LIGHT displayed overlapping and synergistic activities with IL-13 for a number of the activities, but LIGHT additionally enhanced the gene expression of several molecules, including the innate cytokines IL-33 and TSLP, which were not upregulated by IL-13. Our results highlight the varied and pleiotropic effects of LIGHT in HLFs. LIGHT might then be a therapeutic target for modulation of inflammation and remodeling associated with asthma and other similar diseases of the lung that involve fibroblasts.

Recent Understandings of Biology, Prophylaxis and Treatment Strategies for Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are fibroproliferative disorders that may arise after any deep cutaneous injury caused by trauma, burns, surgery, etc. Hypertrophic scars and keloids are cosmetically problematic, and in combination with functional problems such as contractures and subjective symptoms including pruritus, these significantly affect patients’ quality of life. There have been many studies on hypertrophic scars and keloids; but the mechanisms underlying scar formation have not yet been well established, and prophylactic and treatment strategies remain unsatisfactory. In this review, the authors introduce and summarize classical concepts surrounding wound healing and review recent understandings of the biology, prevention and treatment strategies for hypertrophic scars and keloids.