Enhanced Th2 cell differentiation and function in the absence of Nox2

Inhibition of NADPH oxidase 2 enhances resistance to viral neuroinflammation by facilitating M1-polarization of macrophages at the extraneural tissues

BACKGROUND

Macrophages play a pivotal role in the regulation of Japanese encephalitis (JE), a severe neuroinflammation in the central nervous system (CNS) following infection with JE virus (JEV). Macrophages are known for their heterogeneity, polarizing into M1 or M2 phenotypes in the context of various immunopathological diseases. A comprehensive understanding of macrophage polarization and its relevance to JE progression holds significant promise for advancing JE control and therapeutic strategies.

METHODS

To elucidate the role of NADPH oxidase-derived reactive oxygen species (ROS) in JE progression, we assessed viral load, M1 macrophage accumulation, and cytokine production in WT and NADPH oxidase 2 (NOX2)-deficient mice using murine JE model. Additionally, we employed bone marrow (BM) cell-derived macrophages to delineate ROS-mediated regulation of macrophage polarization by ROS following JEV infection.

RESULTS

NOX2-deficient mice exhibited increased resistance to JE progression rather than heightened susceptibility, driven by the regulation of macrophage polarization. These mice displayed reduced viral loads in peripheral lymphoid tissues and the CNS, along with diminished infiltration of inflammatory cells into the CNS, thereby resulting in attenuated neuroinflammation. Additionally, NOX2-deficient mice exhibited enhanced JEV-specific Th1 CD4 + and CD8 + T cell responses and increased accumulation of M1 macrophages producing IL-12p40 and iNOS in peripheral lymphoid and inflamed extraneural tissues. Mechanistic investigations revealed that NOX2-deficient macrophages displayed a more pronounced differentiation into M1 phenotypes in response to JEV infection, thereby leading to the suppression of viral replication. Importantly, the administration of H2O2 generated by NOX2 was shown to inhibit M1 macrophage polarization. Finally, oral administration of the ROS scavenger, butylated hydroxyanisole (BHA), bolstered resistance to JE progression and reduced viral loads in both extraneural tissues and the CNS, along with facilitated accumulation of M1 macrophages.

CONCLUSION

In light of our results, it is suggested that ROS generated by NOX2 play a role in undermining the control of JEV replication within peripheral extraneural tissues, primarily by suppressing M1 macrophage polarization. Subsequently, this leads to an augmentation in the viral load invading the CNS, thereby facilitating JE progression. Hence, our findings ultimately underscore the significance of ROS-mediated macrophage polarization in the context of JE progression initiated JEV infection.

In adult X-CGD patients, regulatory T cells are expanded while activated T cells display a NOX2-independent ROS increase

The X-linked chronic granulomatous disease (X-CGD), a rare genetic disease characterised by recurrent infections, is caused by mutations of NOX2. Significant proportions of X-CGD patients display signs of immune dysregulation. Regulatory T cells (Tregs) are CD4+T lymphocytes that expand in active inflammation and prevent autoimmune disorders. Here we asked whether X-CGD is associated to Treg dysfunctions in adult patients. To this aim, the frequency of Tregs was analysed through intracellular flow cytometry in a cohort of adult X-CGD patients, carriers and controls. We found that Tregs were significantly expanded and activated in blood of adult X-CGD patients, and this was associated with activation of conventional CD4+T cells (Tconvs). T cell activation was characterised by accumulation of intracellular ROS, not derived from NOX2 but likely produced by cellular metabolism. The higher TNF production by Tconvs in X-CGD patients might contribute to the expansion of Tregs through the TNFR2 receptor. In summary, our data indicate that Tregs expand in adult X-CGD in response to immune activation, and that the increase of NOX2-independent ROS content is a feature of activated T cells.

Peripheral T Cell Populations are Differentially Affected in Familial Mediterranean Fever, Chronic Granulomatous Disease, and Gout

Both innate errors of immunity, such as familial Mediterranean fever (FMF) and chronic granulomatous disease (CGD), and the common inflammatory disease gout are characterized by episodes of sterile inflammatory attacks in the absence of an infection. While these disorders encompass distinct pathologies due to differentially affected metabolic pathways and inflammasome activation mechanisms, their common features are the excessive production of interleukin (IL)-1ß and innate immune cell hyperreactivity. On the other hand, the role of T cells and innate-like lymphocytes such as gamma delta (γδ) T cells in these pathologies is ill-defined. In order to widen our understanding of T cell involvement in CGD, FMF and gout pathology, we developed multicolour immunophenotyping panels for flow cytometry to characterize γδ T cells as well as CD4 and CD8 T cell populations in terms of their cytokine production, activation status, memory or naive phenotypes, exhaustion status, homing receptor expression, and cytotoxic activity. Our study is the first deep immunophenotyping analysis of T cell populations in CGD, FMF, and gout patients. We found that CGD affects the frequencies and activation status of T cells, while gout impairs the cytokine production capacity of Vδ2 T cells. FMF was characterized by decreased percentages of regulatory T cells in circulation and attenuated IFN-γ production capacity by Vδ2 T cells. Autoinflammatory syndromes and congenital defects of phagocyte differentially affect T cell compartments. Future studies are warranted to assess whether these phenotypical changes are relevant for disease pathology.

Immunoregulatory mechanism of acute kidney injury in sepsis: A Narrative Review

Sepsis acute kidney injury (SAKI) is a common complication of sepsis, accounting for 26-50 % of all acute kidney injury (AKI). AKI is an independent risk factor for increased mortality risk in patients with sepsis. The excessive inflammatory cascade reaction in SAKI is one of the main causes of kidney damage. Both the innate immune system and the adaptive immune system are involved in the inflammation process of SAKI. Under the action of endotoxin, neutrophils, monocytes, macrophages, T cells and other complex immune network reactions occur, and a large number of endogenous inflammatory mediators are released, resulting in the amplification and loss of control of the inflammatory response. The study of immune cells in SAKI will help improve the understanding of the immune mechanisms of SAKI, and will lay a foundation for the development of new diagnostic and therapeutic targets. This article reviews the role of known immune mechanisms in the occurrence and development of SAKI, with a view to finding new targets for SAKI treatment.

Overview of the Mechanisms of Oxidative Stress: Impact in Inflammation of the Airway Diseases

Inflammation of the human lung is mediated in response to different stimuli (e.g., physical, radioactive, infective, pro-allergenic or toxic) such as cigarette smoke and environmental pollutants. They often promote an increase in inflammatory activities in the airways that manifest themselves as chronic diseases (e.g., allergic airway diseases, asthma, chronic bronchitis/chronic obstructive pulmonary disease (COPD) or even lung cancer). Increased levels of oxidative stress (OS) reduce the antioxidant defenses, affect the autophagy/mitophagy processes, and the regulatory mechanisms of cell survival, promoting inflammation in the lung. In fact, OS potentiate the inflammatory activities in the lung, favoring the progression of chronic airway diseases. OS increases the production of reactive oxygen species (ROS), including superoxide anions (O₂^-), hydroxyl radicals (OH) and hydrogen peroxide (H₂O₂), by the transformation of oxygen through enzymatic and non-enzymatic reactions. In this manner, OS reduces endogenous antioxidant defenses in both nucleated and non-nucleated cells. The production of ROS in the lung can derive from both exogenous insults (cigarette smoke or environmental pollution) and endogenous sources such as cell injury and/or activated inflammatory and structural cells. In this review, we describe the most relevant knowledge concerning the functional interrelation between the mechanisms of OS and inflammation in airway diseases.

Molecular mechanisms of oxidative stress in asthma

The lungs are exposed to reactive oxygen species oxygen (ROS) produced as a result of inhalation of oxygen, as well as smoke and other air pollutants. Cell metabolism and the NADPH oxidases (Nox) generate low levels of intracellular ROS that act as signal transduction mediators by inducing oxidative modifications of histones, enzymes and transcription factors. Redox signalling is also regulated by localised production and sensing of ROS in mitochondria, the endoplasmic reticulum (ER) and inside the nucleus. Intracellular ROS are maintained at low levels through the action of a battery of enzymatic and non-enzymatic antioxidants. Asthma is a heterogeneous airway inflammatory disease with different immune endotypes; these include atopic or non-atopic Th2 type immune response associated with eosinophilia, or a non-Th2 response associated with neutrophilia. Airway remodelling and hyperresponsiveness accompany the inflammatory response in asthma. Over-production of ROS resulting from infiltrating immune cells, particularly eosinophils and neutrophils, and a concomitant impairment of antioxidant responses lead to development of oxidative stress in asthma. Oxidative stress is augmented in severe asthma and during exacerbations, as well as by air pollution and obesity, and causes oxidative damage of tissues promoting airway inflammation and hyperresponsiveness. Furthermore, deregulated Nox activity, mitochondrial dysfunction, ER stress and/or oxidative DNA damage, resulting from exposure to irritants, inflammatory mediators or obesity, may lead to redox-dependent changes in cell signalling. ROS play a central role in airway epithelium-mediated sensing, development of innate and adaptive immune responses, and airway remodelling and hyperresponsiveness. Nonetheless, antioxidant compounds have proven clinically ineffective as therapeutic agents for asthma, partly due to issues with stability and in vivo metabolism of these compounds. The compartmentalised nature of ROS production and sensing, and the role of ROS in homeostatic responses and in the action of corticosteroids and β2-adrenergic receptor agonists, adds another layer of complexity to antioxidant therapy development. Nox inhibitors and mitochondrial-targeted antioxidants are in clinical development for a number of diseases but they have not yet been investigated in asthma. A better understanding of the complex role of ROS in the pathogenesis of asthma will highlight new opportunities for more targeted and effective redox therapies.

Beyond the Extra Respiration of Phagocytosis: NADPH Oxidase 2 in Adaptive Immunity and Inflammation

Reactive oxygen species (ROS) derived from the phagocyte NADPH oxidase (NOX2) are essential for host defence and immunoregulation. Their levels must be tightly controlled. ROS are required to prevent infection and are used in signalling to regulate several processes that are essential for normal immunity. A lack of ROS then leads to immunodeficiency and autoinflammation. However, excess ROS are also deleterious, damaging tissues by causing oxidative stress. In this review, we focus on two particular aspects of ROS biology: (i) the emerging understanding that NOX2-derived ROS play a pivotal role in the development and maintenance of adaptive immunity and (ii) the effects of excess ROS in systemic disease and how limiting ROS might represent a therapeutic avenue in limiting excess inflammation.

Deficiency of voltage-gated proton channel Hv1 aggravates ovalbumin-induced allergic lung asthma in mice

Asthma is a chronic airway inflammation that caused by many factors. The voltage-gated proton channel Hv1 has been proposed to extrude excessive protons produced by NADPH oxidase (NOX) from cytosol to maintain its activity during respiratory bursts. Here, we showed that loss of Hv1 aggravates ovalbumin (OVA)-induced allergic lung asthma in mice. The numbers of total cells, eosinophils and neutrophils in bronchoalveolar lavage fluid (BALF) of Hv1-deficiency (KO) mice are obviously increased after OVA challenge compared with that of wild-type (WT) mice. Histopathological staining reveals that Hv1-deficiency aggravates OVA-induced inflammatory cell infiltration and goblet cell hyperplasia in lung tissues. The expression of IL-4, IL-5 and IL-13 are markedly increased in lung tissues of OVA-challenged KO mice compared with that of WT mice. Furthermore, the expression levels of NOX2, NOX4 and DUOX1 are dramatically increased, while the expression levels of SOD2 and catalase are significantly reduced in lung tissues of OVA-challenged KO mice compared with that of WT mice. The production of ROS in lung tissues of KO mice is significantly higher than that of WT mice after OVA challenge. Our data suggest that Hv1-deficiency might aggravate the development of allergic asthma through increasing ROS production.

Root extract of Angelica reflexa B.Y.Lee reduces allergic lung inflammation by regulating Th2 cell activation

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally, the roots of Angelica reflexa B.Y.Lee (AR) have been used to treat cough, phlegm, neuralgia, and arthralgia in Northeast Asia.

AIM OF THE STUDY

The anti-asthmatic effect of AR root extract (ARE) was determined using a murine airway allergic inflammation model and the primary T cell polarization assay.

MATERIALS AND METHODS

To evaluate the anti-asthmatic effect of ARE, inflammatory cell infiltration was determined histologically and inflammatory mediators were measured in bronchoalveolar lavage fluid (BALF). Furthermore, the effects of AREs on Th2 cell differentiation and activation were determined by western blotting and flow cytometry.

RESULTS

Asthmatic phenotypes were alleviated by ARE treatment, which reduced mucus production, inflammatory cell infiltration (especially eosinophilia), and type 2 cytokine levels in BALF. ARE administration to mice reduced the number of activated Th2 (CD4⁺CD25⁺) cells and level of GATA3 in the lungs. Furthermore, ARE treatment inhibited the differentiation of Th2 cells in primary cell culture systems via interferon regulatory factor 4 (IRF4) signaling.

CONCLUSIONS

Our findings indicate that the anti-asthmatic effect of AREs is mediated by the reduction in Th2 cell activation by regulating IRF4.

Metabolic Reprogramming and Reactive Oxygen Species in T Cell Immunity

T cells undergo metabolic reprogramming and multiple biological processes to satisfy their energetic and biosynthetic demands throughout their lifespan. Several of these metabolic pathways result in the generation of reactive oxygen species (ROS). The imbalance between ROS generation and scavenging could result in severe damage to the cells and potential cell death, ultimately leading to T cell-related diseases. Interestingly, ROS play an essential role in T cell immunity. Here, we introduce the important connectivity between T cell lifespan and the metabolic reprogramming among distinct T cell subsets. We also discuss the generation and sources of ROS production within T cell immunity as well as highlight recent research concerning the effects of ROS on T cell activities.

Sojadodamgangki-tang attenuates allergic lung inflammation by inhibiting T helper 2 cells and Augmenting alveolar macrophages

ETHNOPHARMACOLOGICAL RELEVANCE

Sojadodamgangki-tang (SDG) is a traditional East-Asian herbal medicine mainly composed of Pinellia ternate (Thunb.) Makino, Perilla frutescens (L.) Britt and 10 kinds of medicinal herbs. It has been used to treat asthma and mucus secretion including lung and bronchi.

AIM OF THE STUDY

The aim of this study was to investigate the anti-inflammatory effects of Sojadodamgangki-tang (SDG) on allergic lung inflammation in vitro and in vivo as well as the underlying mechanisms.

MATERIALS AND METHODS

We used an ovalbumin (OVA)-induced murine allergic airway inflammation model. Five groups of 8-week-old female BALB/C mice were divided into the following groups: saline control group, the vehicle (allergic) group that received OVA only, groups that received OVA and SDG (200 mg/kg or 400 mg/kg), and a positive control group that received OVA and Dexamethasone (5 mg/kg). In vitro experiments include T helper 2 (TH2) polarization system, murine macrophage cell culture, and human bronchial epithelial cell line (BEAS-2B) culture.

RESULTS

SDG administration reduced allergic airway inflammatory cell infiltration, especially of eosinophils, mucus production, Th2 cell activation, OVA-specific immunoglobulin E (IgE), and total IgE production. Moreover, the activation of alveolar macrophages, which leads to immune tolerance in the steady state, was promoted by SDG treatment. Interestingly, SDG treatment also reduced the production of alarmin cytokines by the human bronchial epithelial cell line BEAS-2B stimulated with urban particulate matter.

CONCLUSION

Our findings indicate that SDG has potential as a therapeutic drug to inhibit Th2 cell activation and promote alveolar macrophage activation.

Expression of nicotinamide adenine dinucleotide phosphate oxidase in chronic rhinosinusitis with nasal polyps

BACKGROUND

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase produces reactive oxygen species (ROS) involved in oxidative stress and signal transduction. Recent studies have suggested that NADPH oxidase is associated with the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP). The aim of this study was to detect the expression of NADPH oxidase subunits and 4-hydroxynonenal (4-HNE) in nasal polyp tissue and normal nasal mucosa, in order to explore the possible role played by NADPH oxidase in the pathogenesis of CRSwNP.

METHODS

Thirteen patients with CRSwNP and 9 normal control subjects were selected to participate in this study, in which we evaluated the expression of different NADPH oxidase subunits (gp91^phox , p67^phox , p47^phox , and p22^phox ) in nasal polyp (NP) tissue and control mucosa by Western blotting and real-time polymerase chain reaction (PCR). Immunohistochemistry and immunofluorescence staining were used to detect expression of the p67^phox subunit and 4-HNE in NP tissue and normal nasal mucosa.

RESULTS

Western blot and real-time PCR results showed that p67^phox expression was significantly increased in NP tissue when compared with its expression in control mucosa (p = 0.004). p67^phox was expressed in the eosinophils and neutrophils found in NP tissue, but not in the macrophages. Additionally, the levels of 4-HNE expression were also significantly increased in NP tissue when compared with control mucosa (p = 0.001).

CONCLUSION

The levels of p67^phox messenger RNA (mRNA) and protein as well as 4-HNE were both upregulated in NP tissue, suggesting that p67^phox and oxidative stress play roles in the pathogenesis of CRSwNP.

Anti-asthmatic effects of lepidii seu Descurainiae Semen plant species in ovalbumin-induced asthmatic mice

ETHNOPHARMACOLOGICAL EVIDENCE

Lepidii seu Descurainiae Semen (LDS) is used as a traditional herbal medicine in northeast Asia, mainly in Korea, Japan, and China to treat lung disorders including coughs and phlegm caused by acute and chronic airway inflammation.

AIM OF THE STUDY

Recently, interest regarding health problems incurred by air pollution has rapidly grown. Herbal medicines are being considered as alternative agents to treat various diseases. In the present study, we evaluated and compared the anti-inflammatory effects of LDS, which is derived from Lepidium apetalum Willd. extracts (LAE) and Descurainia sophia (L.) Webb ex Prantl extracts (DSE), on allergic airway inflammation.

MATERIALS AND METHODS

We established an ovalbumin-induced asthmatic mouse model to evaluate the efficacy of LDS extracts. We performed histological examination and measured relevant inflammatory mediators and cells in bronchoalveolar lavage fluid and lung. Furthermore, we conducted an in vitro T helper 2 (Th2) polarization assay, flow cytometry, and western blot analysis.

RESULTS

Asthmatic phenotypes were attenuated by LDS extract treatments. LDS extract administration significantly reduced mucus production, inflammatory cell infiltration into airways, and eosinophil activation. Furthermore, LDS extracts reduced the expression of type 2 cytokines and inhibited differentiation and activation of Th2 cells.

CONCLUSION

LDS alleviated eosinophilic inflammation by inhibiting Th2 cell differentiation, and DSE was more effective in attenuating allergic lung inflammation than LAE.

Cholinergic neuron-like D-U87 cells promote polarization of allergic rhinitis T-helper 2 cells

BACKGROUND

Parasympathetic nerve hypersensitivity contributes to the severity of allergic rhinitis (AR), but the precise mechanism underlying neuroimmune regulation in patients with AR remains unclear. This study investigated the effect of cholinergic nerve inhibition on AR CD4⁺ T-helper (Th)2-cell polarization and the underlying regulatory mechanism in vitro.

METHODS

An in-vitro neuroimmune coculture model of D-U87 cells and CD4⁺ T cells was established. D-U87 cells with cholinergic neuron characteristics were used as cholinergic neuron models. CD4⁺ T cells were derived from peripheral blood monocytes from AR patients (n = 60) and control subjects (n = 40). Th1- and Th2-cell percentages were measured by flow cytometry. Proteins involved in related signaling pathways were analyzed by protein chip assay and Western blotting.

RESULTS

The Th2-cell percentage among CD4⁺ T cells from AR patients was significantly increased after coculture with D-U87 cells and was decreased by ipratropium bromide (IB) treatment. In contrast, the Th1-cell percentage among control CD4⁺ T cells was significantly increased after coculture with D-U87 cells, but was unaltered by IB treatment. Furthermore, phosphorylated Akt (p-Akt) protein levels increased in CD4⁺ T cells from both controls and AR patients after coculture with D-U87 cells and decreased after IB treatment. However, higher p-Akt levels were observed in cells from AR patients than in cells from control subjects. Moreover, Akt inhibition decreased Th2-cell percentage in AR patients.

CONCLUSION

In-vitro cholinergic nerve inhibition with IB decreased AR CD4⁺ T-cell polarization into Th2 cells partially through an Akt-dependent mechanism.

Regulatory T cell features in chronic granulomatous disease

Chronic granulomatous disease (CGD) is a primary immunodeficiency caused by mutations in any of the genes encoding the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system, responsible for the production of reactive oxygen species (ROS). CGD is marked by invasive bacterial and fungal infections and by autoinflammation/autoimmunity, of which the exact pathophysiology remains elusive. Contributing factors include decreased neutrophil apoptosis, impaired apoptotic neutrophil clearance, increased proinflammatory protein expression and reduced ROS-mediated inflammasome dampening. We have explored a fundamentally different potential mechanism: it has been reported that macrophage-mediated induction of regulatory T cells (T_regs ) depends on ROS production. We have investigated whether numerical or functional deficiencies exist in T_regs of CGD patients. As the prevalence of autoinflammation/autoimmunity differs between CGD subtypes, we have also investigated T_regs from gp91^phox -, p47^phox - and p40^phox -deficient CGD patients separately. Results show that T_reg numbers and suppressive capacities are not different in CGD patients compared to healthy controls, with the exception that in gp91^phox -deficiency effector T_reg (eT_reg ) numbers are decreased. Expression of T_reg markers CD25, inducible T cell co-stimulator (ICOS), Helios, cytotoxic T lymphocyte antigen 4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor receptor (GITR) did not provide any clue for differences in T_reg functionality or activation state. No correlation was seen between eT_reg numbers and patients' clinical phenotype. To conclude, the only difference between T_regs from CGD patients and healthy controls is a decrease in circulating eT_regs in gp91^phox -deficiency. In terms of autoinflammation/autoimmunity, this group is the most affected. However, upon culture, patient-derived T_regs showed a normal phenotype and normal functional suppressor activity. No other findings pointed towards a role for T_regs in CGD-related autoinflammation/autoimmunity.

Anthriscus sylvestris root extract reduces allergic lung inflammation by regulating interferon regulatory factor 4-mediated Th2 cell activation

ETHNOPHARMACOLOGICAL RELEVANCE

Anthriscus sylvestris L. Hoffmann (AS) is a perennial plant that grows in Asia and Eastern Europe. Its dried root is used to treat conditions such as asthma, bronchitis, and cough.

AIM OF THE STUDY

The present study investigated the anti-inflammatory effects of whole AS extract (ASE) on allergic lung inflammation in vitro and in vivo as well as the underlying mechanisms.

MATERIALS AND METHODS

We used an ovalbumin (OVA)-induced asthma mouse model and in vitro primary T helper (Th)2 polarization system. Five groups of 8-week-old female C57BL/6 mice were divided into the following groups: saline control, or OVA-induced allergic asthma with vehicle, ASE (100 or 200 mg/kg), or dexamethasone (5 mg/kg) treatment for 7 days.

RESULTS

ASE attenuated mucus secretion in airway epithelial cells, inflammatory cell infiltration, eosinophilia, and Th2 cytokine levels in bronchoalveolar lavage fluid. Mice administered ASE showed reductions in the activated cluster of differentiation 4⁺ T cell population and GATA-binding protein-3 gene expression in the lung, and diminished Th2 cell differentiation and activation in vitro. Furthermore, ASE-treated mice showed decreased interleukin-6 and interferon regulatory factor (IRF)4 expression, with corresponding reductions in nitric oxide levels in the lungs of asthmatic mice and in stimulated RAW cells.

CONCLUSION

ASE exerts anti-asthmatic effects by inhibiting IRF4 expression and thereby suppressing Th2 cell activation.

Precision medicine and phenotypes, endotypes, genotypes, regiotypes, and theratypes of allergic diseases

A rapidly developing paradigm for modern health care is a proactive and individualized response to patients' symptoms, combining precision diagnosis and personalized treatment. Precision medicine is becoming an overarching medical discipline that will require a better understanding of biomarkers, phenotypes, endotypes, genotypes, regiotypes, and theratypes of diseases. The 100-year-old personalized allergen-specific management of allergic diseases has particularly contributed to early awareness in precision medicine. Polyomics, big data, and systems biology have demonstrated a profound complexity and dynamic variability in allergic disease between individuals, as well as between regions. Escalating health care costs together with questionable efficacy of the current management of allergic diseases facilitated the emergence of the endotype-driven approach. We describe here a precision medicine approach that stratifies patients based on disease mechanisms to optimize management of allergic diseases.

Codonopsis lanceolata attenuates allergic lung inflammation by inhibiting Th2 cell activation and augmenting mitochondrial ROS dismutase (SOD2) expression

Allergic asthma is a chronic inflammatory disease induced by the inhalation of allergens, which trigger the activation of T helper type 2 (Th2) cells that release Th2 cytokines. Recently, herbal medicines are being considered a major source of novel agents to treat various diseases. In the present study, we evaluated the anti-asthmatic effects of a Codonopsis lanceolata extract (CLE) and the mechanisms involved in its anti-inflammatory effects. Treatment with CLE reduced infiltration of inflammatory cells, especially eosinophils, and the production of mucus in lung tissues. Levels of Th2 cytokines, such as IL-4, IL-5, and IL-13, and chemokines were also decreased following treatment with CLE. Moreover, Th2 cell proportion in vivo and differentiation in vitro were reduced as evidenced by the decreased expression of GATA3⁺. Furthermore, the expression of superoxide dismutase (SOD)2, a mitochondrial ROS (mROS) scavenger, was increased, which was related to Th2 cell regulation. Interestingly, treatment with CLE increased the number of macrophages in the lungs and enhanced the immune-suppressive property of macrophages. Our findings indicate that CLE has potential as a novel therapeutic agent to inhibit Th2 cell differentiation by regulating mROS scavenging.

Gastrointestinal Complications in Chronic Granulomatous Disease

Almost half of patients with chronic granulomatous disease (CGD) suffer from gastrointestinal (GI) inflammation, the pathogenesis of which is complex and multifactorial. As a result, the management of CGD-associated GI inflammation remains challenging due to its chronicity and difficulty in managing the simultaneous need for immunomodulation with increased susceptibility to infection. In order to contextualize prospective treatment interventions for CGD-associated GI inflammation, we have reviewed the clinical presentation, pathogenesis and current management of this disease. Increased understanding of the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex 2 (NOX2)-derived reactive oxygen species (ROS) in inflammatory bowel disease (IBD) will likely reveal novel targets for therapeutic intervention.

Effects of 18β-Glycyrrhetinic Acid on Fungal Protease-Induced Airway Inflammatory Responses

Airway epithelial cells secrete diverse inflammatory mediators in response to various stimuli. Thus, early regulation of immune responses in the airway epithelium is likely critical for the control of chronic inflammatory diseases. The purpose of the present study was to evaluate the effects of 18β-glycyrrhetinic acid (GA) on inflammatory responses generated in response to a fungal protease allergen that induces epithelial damage. To understand the underlying mechanisms, we also investigated the inhibitory effects of GA on the production of mitochondrial reactive oxygen species (ROS) in the human bronchial epithelial cell line BEAS2B. In this study, GA treatment reduced cytokine production and the human neutrophil cell line HL60 migration through decreased mitochondrial ROS production. In addition, GA significantly reduced inflammatory cell infiltration and cytokine levels in the bronchoalveolar lavage (BAL) fluid of fungal allergen-administered mice. Inhibitory effects of GA are dependent on the mitochondrial ROS/MAPK axis. Moreover, the effect of GA on the regulation of mitochondrial ROS depends on the expression of uncoupling protein-2 (UCP-2). Taken together, GA might represent a potential therapeutic agent for blocking inflammatory responses in airways.

Peucedanum japonicum extract attenuates allergic airway inflammation by inhibiting Th2 cell activation and production of pro-inflammatory mediators

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Peucedanum japonicum Thunberg is traditionally used to treat coughs, colds, headache and inflammatory diseases in Korea and Japan. Its effects on allergic lung inflammation have not been investigated.

AIM OF THE STUDY

To investigate the anti-asthmatic effects of Peucedanum japonicum extract (PJE) using a murine model of asthma and a lipopolysaccharide (LPS)-stimulated macrophage cell line.

MATERIALS AND METHODS

Mice underwent two rounds of sensitization with ovalbumin 1 week apart followed by four intranasal ovalbumin challenges on days 13-16. The control group received saline only. Two ovalbumin-sensitized groups were orally administered vehicle or PJE (200mg/kg) 5 days a week starting 1 week before the first ovalbumin sensitization. The third group was orally administered the asthma medication Montelukast (10mg/kg) on days 12-16. All animals were sacrificed on day 17. The lungs were assessed for histological features, inflammatory cell infiltration, Th2 cell activation and GATA-binding protein-3 (GATA-3) expression. The bronchoalveolar lavage fluid (BALF) was assessed for type 2 cytokine levels. The effect of PJE on the in vitro Th2 polarization of naïve CD4⁺ splenocytes and the production of pro-inflammatory mediators and cytokines by LPS-stimulated RAW 264.7 cells was evaluated.

RESULTS

PJE treatment inhibited OVA-induced inflammatory cell infiltration, eosinophilia, Th2 activation, and GATA-3 expression in the lung, reduced the interleukin (IL)-5 and IL-13 levels in BALF, down-regulated Th2 activation in vitro, and inhibited the macrophage production of inducible nitric oxide, cyclooxygenase-2, tumor necrosis factor-α, and IL-6.

CONCLUSION

PJE attenuated allergic airway inflammation by inhibiting Th2 cell activation and macrophage production of inflammatory mediators. Peucedanum japonicum may be candidate therapy for allergic lung inflammation.

Increased Expression of p22phox Mediates Airway Hyperresponsiveness in an Experimental Model of Asthma

AIM

Chronic airway diseases such as asthma are associated with increased production of reactive oxygen species (ROS) and oxidative stress. Endogenous NADPH oxidases are a major source of superoxide in lung, but their underlying role in asthma pathology is poorly understood. We sought to characterize the involvement of NADPH oxidase in allergic asthma by studying the role of CYBA (p22phox) in human asthma and murine house dust mite (HDM)-induced allergic airway inflammation.

RESULTS

Increased expression and localization of p22-PHOX were observed in biopsies of asthmatic patients. HDM-treated wild-type mice possessed elevated p22phox expression, corresponding with elevated superoxide production. p22phox knockout (KO) mice did not induce superoxide and were protected against HDM-induced goblet cell hyperplasia and mucus production and HDM-induced airway hyperresponsiveness (AHR). IL-13-induced tracheal hyperreactivity and signal transducer and activator of transcription (STAT)6 phosphorylation were attenuated in the absence of p22phox or catalase pretreatment.

INNOVATION

Our study identifies increased expression of p22phox in lungs of asthmatic patients and in experimental model. The induced AHR and mucus hypersecretion are a result of increased ROS from the p22phox-dependent NADPH oxidase, which in turn activates STAT6 for the pathological feature of asthma.

CONCLUSIONS

Together with the increased p22phox expression in lungs of asthmatic patients, these findings demonstrate a crucial role of p22phox-dependent NADPH oxidase for the development of mucus hypersecretion and AHR in HDM-induced model of asthma. This suggests that inhibition of functional NADPH oxidase by selective interference of p22phox might hold a promising therapeutic strategy for the management of asthma. Antioxid. Redox Signal. 27, 1460-1472.

Bilirubin nanoparticles ameliorate allergic lung inflammation in a mouse model of asthma

Although asthma, a chronic inflammatory airway disease, is relatively well-managed by inhaled corticosteroids, the side effects associated with the long-term use of these agents precipitate the need for alternative therapeutic options based on differing modes of action. Bilirubin, a potent endogenous antioxidant, and anti-inflammatory molecule have been shown to ameliorate asthmatic symptoms; however, its clinical translation has been limited owing to its water insolubility and associated potential toxicity. Here we report the first application of bilirubin-based nanoparticles (BRNPs) as a nanomedicine for the treatment of allergic lung inflammatory disease. BRNPs were prepared directly from self-assembly of PEGylated bilirubin in aqueous solution and had a hydrodynamic diameter of ∼100 nm. Because allergen-specific type 2 T-helper (Th2) cells play a key role in the pathogenesis and progression of allergic asthma, the effects of BRNPs on Th2 immune responses were investigated both in vivo and in vitro. BRNPs after intravenous injection (i.v.) showed much higher serum concentration and a longer circulation time of bilirubin than the intraperitoneal injection (i.p.) of BRNPs or unconjugated bilirubin (UCB). The anti-asthmatic effects of BRNPs were assessed in a mouse model of allergen-induced asthma. Compared with UCB, treatment with BRNPs suppressed the symptoms of experimental allergic asthma and dramatically ameliorated Th2-related allergic lung inflammation. Consistent with these results, BRNPs caused a reduction of Th2 cell populations and the expression of related cytokines by antibody-stimulated CD4⁺ T cells in vitro. Therefore, our results establish BRNPs as an important immunomodulatory agent that may be useful as a therapeutic for allergic lung inflammatory disease and other immune-mediated disorders.

Major CD4 T-Cell Depletion and Immune Senescence in a Patient with Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) results from primary defects in phagocytic reactive oxygen species (ROS) production. T-cell evaluation is usually neglected during patients’ follow-up, although T-cell depletion has been reported in CGD through unknown mechanisms. We describe here a 36-year-old patient with X-linked CGD with severe CD4 T-cell depletion <200 CD4 T-cells/μl, providing insights into the mechanisms that underlie T-cell loss in the context of oxidative burst defects. In addition to the typical infections, the patient featured a progressive T-cell loss associated with persistent lymphocyte activation, expansion of interleukin (IL)-17-producing CD4 T-cells, and impaired thymic activity, leading to a reduced replenishment of the T-cell pool. A relative CD4 depletion was also found at the gut mucosal level, although no bias to IL-17-production was documented. This immunological pattern of exhaustion of immune resources favors prompt, potentially curative, therapeutic interventions in CGD patients, namely, stem-cell transplantation or gene therapy. Moreover, this clinical case raises new research questions on the interplay of ROS production and T-cell homeostasis and immune senescence.

Reduced allergic lung inflammation by root extracts from two species of Peucedanum through inhibition of Th2 cell activation

ETHNOPHARMACOLOGICAL EVIDENCE

Peucedani Radix (PR), the root of Peucedanum praeruptorum Dunn (PPD) or Peucedanum decursivum (Miq.) Maxim. (PDM), has long been used in Korea to eliminate sputum, relieve cough, and reduce bronchus contraction. Furthermore, these therapeutic strategies are recognized as general and effective methods in western medicine as well as traditional Korean medicine.

AIM OF THE STUDY

To determine and compare the anti-inflammatory effects of PPD extracts (PPDE) and PDM extracts (PDME) on allergic lung inflammation, using in vivo OVA-induced airway inflammation in mice and in vitro primary cell culture systems.

MATERIALS AND METHODS

Eight-week-old female C57BL/6 mice were placed into four groups (n=4 per group): saline control, OVA-induced allergic lung inflammation with vehicle, or PPDE (200mg/kg) or PDME (200mg/kg) treatment. PR extracts (PRE) were administered from 1 week before 1st OVA sensitization to the day before sacrifice. Mice were sacrificed 18h after last OVA intra-nasal challenge followed by histological and biochemical analyses.

RESULTS

Inflammatory phenotypes were alleviated with oral administration of PRE. PRE treatment decreased mucus production in airway epithelium, inflammatory cell number, eosinophilia, type 2 cytokines, and histamine in bronchoalveolar lavage fluid (BALF). Mice with PRE administration showed diminished activated CD4 T cell (CD4⁺CD25⁺ cell) and GATA-3 level in the lung. In addition, PRE treatment reduced Th2 cell activation in vitro, using Th2 polarization system.

CONCLUSION

Our findings indicate that the anti-inflammatory effects of PRE arise from reduced Th2 cell activation and validate the clinical use of PR in traditional Korean medicine.