Involvement of autophagy in exacerbation of eosinophilic airway inflammation in a murine model of obese asthma

AMPK Regulates M1 Macrophage Polarization through the JAK2/STAT3 Signaling Pathway to Attenuate Airway Inflammation in Obesity-Related Asthma

Abstract-Obesity-related asthma is primarily characterized by nonallergic inflammation, with pathogenesis involving oxidative stress, metabolic imbalance, and immunoinflammatory mechanisms. M1 macrophages, which predominantly secrete pro-inflammatory factors, mediate insulin resistance and systemic metabolic inflammation in obese individuals. Concurrently, adenosine monophosphate-activated protein kinase (AMPK) serves as a critical regulator of intracellular energy metabolism and is closely associated with macrophage activation. However, their specific roles and associated mechanisms in obesity-related asthma remain to be explored. In this study, we investigated the macrophage polarization status and potential interventional mechanisms through obesity-related asthmatic models and lipopolysaccharide (LPS) -treated RAW264.7 cell with a comprehensive series of evaluations, including HE, PAS and Masson staining of lung histopathology, immunohistochemical staining, immunofluorescence technology, qRT-PCR, Western Blot, and ELISA inflammatory factor analysis. The results revealed M1 macrophage polarization in obesity-related asthmatic lung tissue alongside downregulation of AMPK expression. Under LPS stimulation, exogenous AMPK activation attenuated M1 macrophage polarization via the Janus kinase 2/ signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Additionally, in obesity-related asthmatic mice, AMPK activation was found to alleviate airway inflammation by regulating M1 macrophage polarization, the mechanism closely associated with the JAK2/STAT3 pathway. These findings not only advance our understanding of macrophage polarization in obesity-related asthma, but also provide new therapeutic targets for its treatment.

TLR2-ERK signaling pathway regulates expression of galectin-3 in a murine model of OVA-induced allergic airway inflammation

Toll-like receptor 2 (TLR2) and galectin-3 (Gal-3) are involved in the pathological process of asthma, but the underlying mechanism is not fully understood. We hypothesized that TLR2 pathway may regulate expression of Gal-3 in allergic airway inflammation. Wild-type (WT) and TLR2-/- mice were sensitized on day 0 and challenged with ovalbumin (OVA) on days 14-21 to establish a model of allergic airway inflammation, and were treated with a specific ERK inhibitor U0126. Histological changes in the lungs were analyzed by hematoxylin-eosin (HE) and Periodic Acid-Schiff (PAS) staining; cytokines and anti-OVA immunoglobulin E (IgE) were tested by ELISA; and related protein expression in lung tissues was measured by western blot. We found that the expression levels of TLR2 and Gal-3 markedly increased concomitantly with airway inflammation after OVA induction, while TLR2 deficiency significantly alleviated airway inflammation and reduced Gal-3 expression. Moreover, the expression levels of phosphorylated mitogen-activated protein kinases (p-MAPKs) were significantly elevated in OVA-challenged WT mice, while TLR2 deficiency only significantly decreased phosphorylated extracellular signal-regulated kinase (p-ERK) levels. Furthermore, we found that U0126 treatment significantly alleviated allergic airway inflammation and decreased Gal-3 levels in OVA-challenged WT mice, but had no further effect in OVA-challenged TLR2-/- mice. These above results suggested that TLR2 is an upstream signal molecule of ERK. We further demonstrated that TLR2 regulates Gal-3 expression through the ERK pathway in LTA-stimulated macrophages in vitro. Our findings showed that the TLR2-ERK signaling pathway regulates Gal-3 expression in a murine model of allergic airway inflammation.

CD109 Attenuates Bleomycin-induced Pulmonary Fibrosis by Inhibiting TGF-β Signaling

Pulmonary fibrosis is a fatal condition characterized by fibroblast and myofibroblast proliferation and collagen deposition. TGF-β plays a pivotal role in the development of pulmonary fibrosis. Therefore, modulation of TGF-β signaling is a promising therapeutic strategy for treating pulmonary fibrosis. To date, however, interventions targeting TGF-β have not shown consistent efficacy. CD109 is a GPI-anchored glycoprotein that binds to TGF-β receptor I and negatively regulates TGF-β signaling. However, no studies have examined the role and therapeutic potential of CD109 in pulmonary fibrosis. The purpose of this study was to determine the role and therapeutic value of CD109 in bleomycin-induced pulmonary fibrosis. CD109-transgenic mice overexpressing CD109 exhibited significantly attenuated pulmonary fibrosis, preserved lung function, and reduced lung fibroblasts and myofibroblasts compared with wild-type (WT) mice. CD109-/- mice exhibited pulmonary fibrosis comparable to WT mice. CD109 expression was induced in variety types of cells, including lung fibroblasts and macrophages, upon bleomycin exposure. Recombinant CD109 protein inhibited TGF-β signaling and significantly decreased ACTA2 expression in human fetal lung fibroblast cells in vitro. Administration of recombinant CD109 protein markedly reduced pulmonary fibrosis in bleomycin-treated WT mice in vivo. Our results suggest that CD109 is not essential for the development of pulmonary fibrosis, but excess CD109 protein can inhibit pulmonary fibrosis development, possibly through suppression of TGF-β signaling. CD109 is a novel therapeutic candidate for treating pulmonary fibrosis.

Carbon black nanoparticles and cadmium co-exposure aggravates bronchial epithelial cells inflammation via autophagy-lysosome pathway

Carbon black nanoparticles (CBNPs) and cadmium (Cd) are major components of various air pollutants and cigarette smoke. Autophagy and inflammation both play critical roles in understanding the toxicity of particles and their components, as well as maintaining body homeostasis. However, the effects and mechanisms of CBNPs and Cd (CBNPs-Cd) co-exposure on the human respiratory system remain unclear. In this study, a CBNPs-Cd exposure model was constructed to explore the respiratory toxicity and combined mechanism of these chemicals on the autophagy-lysosome pathway in the context of respiratory inflammation. Co-exposure of CBNPs and Cd significantly increased the number of autophagosomes and lysosomes in human bronchial epithelial cells (16HBE) and mouse lung tissues compared to the control group, as well as the groups exposed to CBNPs and Cd alone. Autophagic markers, LC3II and P62 proteins, were up-regulated in 16HBE cells and mouse lung tissues after CBNPs-Cd co-exposure. However, treatment with Cq inhibitor (an indicator of lysosomal acid environment) resulted in a substantial decreased co-localization fluorescence of LC3 and lysosomes in the CBNPs-Cd combination group compared with the CBNPs-Cd single and control groups. No difference in LAMP1 protein expression was observed among the exposed groups. Adding 3 MA alleviated inflammatory responses, while applying the Baf-A1 inhibitor aggravated inflammation both in vitro and in vivo following CBNPs-Cd co-exposure. Factorial analysis showed no interaction between CBNPs and Cd in their effects on 16HBE cells. We demonstrated that co-exposure to CBNPs-Cd increases the synthesis of autophagosomes and regulates the acidic environment of lysosomes, thereby inhibiting autophagy-lysosome fusion and enhancing the inflammatory response in both 16HBE cells and mouse lung. These findings provide evidence for a comprehensive understanding of the interaction between CBNPs and Cd in mixed pollutants, as well as for the prevention and control of occupational exposure to these two chemicals.

Anti-inflammatory effects of reticuline on the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathway in a mouse model of obesity-associated asthma

BACKGROUND

Asthma associated with obesity is a chronic disease characterized by earlier airway remodeling, severe wheezing, and increased insensitivity to hormone therapy. Reticuline, a bioactive compound of Magnoliae Flos, exerts anti-inflammatory activity and can inhibit neutrophil recruitment. Thus, this study investigated the role of reticuline in obesity-related asthma.

METHODS

The BALB/c mice fed a low-fat diet (LFD) and high-fat diet (HFD) were intranasally challenged with house dust mites (HDMs) or ovalbumin (OVA). Reticuline (0.25 mg/kg) was administrated into mice by intragastrical gavage. Airway hyper-responsiveness was examined after the final challenge. Body weight was measured, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected. The number of inflammatory cells in BALF was estimated. Histological changes were assessed by performing hematoxylin-eosin staining, and production of proinflammatory cytokines and IgE was examined by ELISA kits. Related pathways were studied with western blotting.

RESULTS

Reticuline suppressed airway resistance and inflammatory infiltration in lung tissue and reduced inflammatory cell recruitment in BALF in obesity mice with asthma. Additionally, the levels of IL-17A, IL-1β, IL-5, macrophage inflammatory protein 2, and regulated on activation, normal T cell expressed and secreted in the lung were reduced by reticuline. Mechanistically, reticuline inactivated the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways in obesity-related asthma.

CONCLUSION

Reticuline alleviates airway inflammation in obesity-related asthma by inactivating the JAK2/STAT3/SOCS3 and p38 MAPK/NF-κB signaling pathways.

Potential role of irisin in lung diseases and advances in research

Irisin, a myokine, is secreted by the movement of skeletal muscles. It plays an important role in metabolic homeostasis, insulin resistance, anti-inflammation, oxidative stress, and bone metabolism. Several studies have reported that irisin-related signaling pathways play a critical role in the treatment of various diseases, including obesity, cardiovascular disease, diabetes, and neurodegenerative disorders. Recently, the potential role of irisin in lung diseases, including chronic obstructive pulmonary disease, acute lung injury, lung cancer, and their associated complications, has received increasing attention. This article aims to explore the role of irisin in lung diseases, primarily focusing on the underlying molecular mechanisms, which may serve as a marker for the diagnosis as well as a potential target for the treatment of lung diseases, thus providing new strategies for their treatment.

Lactobacillus rhamnosus Modulates Lung Inflammation and Mitigates Gut Dysbiosis in a Murine Model of Asthma-COPD Overlap Syndrome

The asthma-COPD overlap syndrome (ACOS) presents lung inflammation similar to both asthma and chronic obstructive pulmonary disease (COPD). Due to the immune response between the lung and gut, it is possible that ACOS individuals present gut dysbiosis. Due to therapeutic limitations in ACOS, Lactobacillus rhamnosus (Lr) have received attention once Lr has been effective in asthma and COPD. However, there is no data about the Lr effect on both lung inflammation and gut dysbiosis in ACOS. Thus, our study investigated the Lr effect on lung inflammation, bronchoconstriction, airway remodeling, and gut dysbiosis in the murine ACOS model. Treated mice with Lr were exposed to HDM and cigarette smoke to induce ACOS. Sixty days after ACOS induction, mice were euthanized. Lung inflammation was evaluated in leukocytes in bronchoalveolar lavage fluid (BALF), airway remodeling, cytokine secretion, and transcription factor expression in the lung. The gut microbiota was assayed by 16S mRNA sequencing from a fecal sample. Leukocyte population, bronchial hyperreactivity, pro-inflammatory cytokines, and airway remodeling were attenuated in Lr-treated ACOS mice. Likewise, IL-4, IL-5, and IL-13, STAT6 and GATA3, as well as IL-17, IL-21, IL-22, STAT3, and RORɣt were reduced after Lr. In addition, IL-2, IL-12, IFN-γ, STAT1, and T-bet as well as IL-10, TGF-β, STAT5, and Foxp3 were restored after the Lr. Firmicutes was reduced, while Deferribacteres was increased after Lr. Likewise, Lr decreased Staphylococcus and increased Mucispirillum in ACOS mice. Lr improves fecal bacterial β-diversity. Our findings show for the first time the Lr effect on lung inflammation and gut dysbiosis in murine ACOS.

Comparison with gastric cancer-associated genes reveals the role of ferroptosis-related genes in eosinophils of asthma patients: A bioinformatic study

Ferroptosis-inducing agents (FIAs) induced lipid-peroxidation-independent ferroptosis in eosinophils, thus ameliorating airway inflammation in asthmatic mice. Differences in ferroptosis-related genes (FerrGs) between eosinophils and cells in which FIAs induce canonical ferroptosis are supposed to contribute to this noncanonical ferroptosis but remain unclear. This study aims to explore these differences. This study used gastric cancer cells (GCCs) in stomach adenocarcinoma as the representative of cells in which FIAs induce canonical ferroptosis. FerrGs in Ferroptosis Database V2 respectively intersected with differentially expressed genes (DEGs) of eosinophils (E-MTAB-4660 dataset) and GCCs (GEPIA2 Stomach adenocarcinoma dataset) to obtain original ferroptosis DEGs (FerrDEGs). Then, they were subjected to Venn analysis to identify FerrDEGs shared by them and FerrDEGs exclusively expressed in eosinophils or GCCs. Identified genes were subjected to functional enrichment analysis, protein-protein interactions analysis, Hub genes analysis, and construction of the LncRNA-mediated ceRNA network. Sixty-six original FerrDEGs in eosinophils and 110 original FerrDEGs in GCCs were obtained. Venn analysis identified that eosinophils and GCCs shared 19 FerrDEGs that presented opposite expression directions and were involved in the ferroptosis pathway. Four upregulated and 20 downregulated FerrDEGs were exclusively expressed in eosinophils and GCCs, respectively. The former were enriched only in glycerolipid metabolism, while the latter were not enriched in pathways. Forty downregulated and 68 upregulated FerrDEGs were solely expressed in eosinophils and GCCs, respectively. The former was associated with the FoxO signaling pathway; the latter was related to glutathione metabolism and they were all implicated in autophagy. PPI analysis shows that the top 10 Hub genes of 66 original FerrDEGs and 44 exclusive FerrDEGs in eosinophils shared 9 genes (STAT3, NFE2L2, MAPK8, PTEN, MAPK3, TLR4, SIRT1, BECN1, and PTGS2) and they were also involved in the FoxO signaling pathway and autophagy pathway. Among them, PTEN is involved in forming a ceRNA network containing 3 LncRNAs, 3 miRNAs and 3 mRNAs. In contrast to FerrGs in cells in which FIAs induce canonical ferroptosis, the FerrGs in eosinophils differ in expression and in the regulation of ferroptosis, FoxO signaling pathway, and autophagy. It lays the groundwork for targeted induction of eosinophils lipid-peroxidation-independent ferroptosis in asthma.

Serum autophagy protein 5 is positively related to T helper 2/T helper 1 ratio, inflammation, and exacerbation in adult asthma patients

BACKGROUND

Autophagy protein 5 (ATG5) regulates airway epithelial cell autophagy, immune response, and inflammation, which is involved in asthma progression. This study aimed to evaluate ATG5 levels and its clinical roles in adult asthma patients.

METHODS

Totally, 200 adult asthma patients and 100 healthy controls (HCs) were enrolled in this case-control study. Subsequently, serum ATG5 was measured by enzyme-linked immunosorbent assay.

RESULTS

ATG5 was increased in asthma patients compared with HCs [median (interquartile range): 44.2 (31.7-77.8) vs. 23.2 (16.7-39.2) ng/mL] (P < 0.001). In asthma patients, ATG5 was positively related to male gender (P = 0.022), a family history of asthma (P = 0.035), eosinophil count (P < 0.001), and immune globulin E (P < 0.001), while it was negatively correlated with forced expiratory volume in 1 s (FEV1)/forced vital capacity (P < 0.001) and FEV1 (Predicted) (P < 0.001). Meanwhile, ATG5 was inversely associated with T helper (Th) 1 cells (P = 0.008), while it was positively linked with Th2 cells (P < 0.001), Th2/Th1 ratio (P < 0.001), interleukin (IL)-4 (P = 0.002), and IL-4/interferon-γ ratio (P = 0.015). Additionally, ATG5 was positively correlated with tumor necrosis factor-α (P < 0.001), IL-1β (P = 0.001), IL-6 (P = 0.003), and IL-17 (P = 0.029). Notably, ATG5 was elevated in asthma patients at exacerbation compared to those at remission [median (interquartile range): 53.6 (37.6-90.0) vs. 35.6 (28.2-51.5) ng/mL] (P < 0.001). It was also noteworthy that ATG5 was positively linked with exacerbation severity in asthma patients (P = 0.005).

CONCLUSION

Serum ATG5 is related to increased Th2/Th1 ratio, inflammation, exacerbation risk and severity in adult asthma patients, which serves as a candidate marker for the management of asthma. However, further validation is still needed.

Autophagy/Mitophagy in Airway Diseases: Impact of Oxidative Stress on Epithelial Cells

Autophagy is the key process by which the cell degrades parts of itself within the lysosomes. It maintains cell survival and homeostasis by removing molecules (particularly proteins), subcellular organelles, damaged cytoplasmic macromolecules, and by recycling the degradation products. The selective removal or degradation of mitochondria is a particular type of autophagy called mitophagy. Various forms of cellular stress (oxidative stress (OS), hypoxia, pathogen infections) affect autophagy by inducing free radicals and reactive oxygen species (ROS) formation to promote the antioxidant response. Dysfunctional mechanisms of autophagy have been found in different respiratory diseases such as chronic obstructive lung disease (COPD) and asthma, involving epithelial cells. Several existing clinically approved drugs may modulate autophagy to varying extents. However, these drugs are nonspecific and not currently utilized to manipulate autophagy in airway diseases. In this review, we provide an overview of different autophagic pathways with particular attention on the dysfunctional mechanisms of autophagy in the epithelial cells during asthma and COPD. Our aim is to further deepen and disclose the research in this direction to stimulate the develop of new and selective drugs to regulate autophagy for asthma and COPD treatment.

Programmed Cell Death in Asthma: Apoptosis, Autophagy, Pyroptosis, Ferroptosis, and Necroptosis

Bronchial asthma is a complex heterogeneous airway disease, which has emerged as a global health issue. A comprehensive understanding of the different molecular mechanisms of bronchial asthma may be an efficient means to improve its clinical efficacy in the future. Increasing research evidence indicates that some types of programmed cell death (PCD), including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis, contributed to asthma pathogenesis, and may become new targets for future asthma treatment. This review briefly discusses the molecular mechanism and signaling pathway of these forms of PCD focuses on summarizing their roles in the pathogenesis and treatment strategies of asthma and offers some efficient means to improve clinical efficacy of therapeutics for asthma in the near future.

PIF1 Promotes Autophagy to Inhibit Chronic Hypoxia Induced Apoptosis of Pulmonary Artery Endothelial Cells

Purpose

Pulmonary artery hypertension (PAH) is a common complication of chronic obstructive pulmonary disease and obstructive sleep apnea/hypopnea syndrome worldwide. Pulmonary vascular alterations associated with PAH have multifactorial causes, in which endothelial cells play an important role. Autophagy is closely related to endothelial cell injury and the development of PAH. PIF1 is a multifunctional helicase crucial for cell survival. The present study investigated the effect of PIF1 on autophagy and apoptosis in human pulmonary artery endothelial cells (HPAECs) under chronic hypoxia stress.

Methods

Chronic hypoxia Gene expression profiling chip-assays identified the PIF1 gene as differentially expressed, which was verified by RT-qPCR analysis. Electron microscopy, immunofluorescence, and Western blotting were used to analyze autophagy and the expression of LC3 and P62. Apoptosis was analyzed using flow cytometry.

Results

Our study found that chronic hypoxia induces autophagy in HPAECs, and apoptosis was exacerbated by inhibiting autophagy. Levels of the DNA helicase PIF1 were increased in HPAECs after chronic hypoxia. PIF1 knockdown inhibited autophagy and promoted the apoptosis of HPAECs under chronic hypoxia stress.

Conclusion

Based on these findings, we conclude that PIF1 inhibits the apoptosis of HPAECs by accelerating the autophagy pathway. Therefore, PIF1 plays a crucial role in HPAEC dysfunction in chronic hypoxia-induced PAH and may be a potential target for the treatment of PAH.

T-helper cells and their cytokines in pathogenesis and treatment of asthma

Prosperous advances in understanding the cellular and molecular mechanisms of chronic inflammation and airway remodeling in asthma have been made over the past several decades. Asthma is a chronic inflammatory disease of the airways characterized by reversible airway obstruction that is self-resolving or remits with treatment. Around half of asthma patients are "Type-2-high" asthma with overexpression of type 2 inflammatory pathways and elevated type 2 cytokines. When stimulated by allergens, airway epithelial cells secrete IL-25, IL-33, and TSLP to derive a Th2 immune response. First ILC2 followed by Th2 cells produces a series of cytokines such as IL-4, IL-5, and IL-13. T_FH cells control IgE synthesis by secreting IL-4 to allergen-specific B cells. IL-5 promotes eosinophil inflammation, while IL-13 and IL-4 are involved in goblet cell metaplasia and bronchial hyperresponsiveness. Currently, "Type-2 low" asthma is defined as asthma with low levels of T2 biomarkers due to the lack of reliable biomarkers, which is associated with other Th cells. Th1 and Th17 are capable of producing cytokines that recruit neutrophils, such as IFN-γ and IL-17, to participate in the development of "Type-2-low" asthma. Precision medicine targeting Th cells and related cytokines is essential in the management of asthma aiming at the more appropriate patient selection and better treatment response. In this review, we sort out the pathogenesis of Th cells in asthma and summarize the therapeutic approaches involved as well as potential research directions.

Inadequate therapeutic responses to glucocorticoid treatment in bronchial asthma

Bronchial asthma (BA) is a heterogeneous disease. Some patients benefit greatly from glucocorticoid (GC) treatment, whereas others are non-responders. This could be attributable to differences in pathobiology. Thus, predicting the responses to GC treatment in patients with BA is necessary to increase the success rates of GC therapy and avoid adverse effects. The sustained inflammation in BA decreases glucocorticoid receptor (GR, NR3C1) function. Meanwhile, GRβ overexpression might contribute to GC resistance. Important factors in decreased GR function include p38 mitogen-activated protein kinase-dependent GR phosphorylated at Ser226, reduced expression of histone deacetylase 2 following activation of the phosphatidylinositol 3-kinase-δ signaling pathway, and increased nuclear factor-kappa B activity. MicroRNAs, which are involved in GC sensitivity, are considered biomarkers of the response to inhaled GCs. Some studies revealed that inflammatory phenotypes and disease-related modifiable factors, including infections, the airway microbiome, mental stress, smoking, and obesity, regulate individual sensitivity to GCs. Therefore, future investigations are warranted to improve treatment outcomes.

CD109 on Dendritic Cells Regulates Airway Hyperreactivity and Eosinophilic Airway Inflammation

Asthma is a chronic airway inflammatory disease characterized by airway hyperreactivity (AHR) and eosinophilic airway inflammation. Dendritic cells (DCs) are essential for the development of asthma via presenting allergens, causing T-helper cell type 2 (Th2) skewing and eosinophil inflammation. Recent studies have revealed that CD109, a glycosylphosphatidylinositol-anchored glycoprotein, is involved in the pathogenesis of inflammatory diseases such as rheumatoid arthritis and psoriasis. However, no study has addressed the role of CD109 in asthma. This study sought to address the role of CD109 on DCs in the development of AHR and allergic inflammation. CD109-deficient mice (CD109^-/-) were sensitized with house dust mite or ovalbumin and compared with wild-type mice for induction of AHR and allergic inflammation. CD109-deficient mice had reduced AHR and eosinophilic inflammation together with lower Th2 cytokine expression compared with wild-type mice. Interestingly, CD109 expression was induced in lung conventional DC2s (cDC2s), but not lung cDC1s, upon allergic challenge. Lung cDC2s from CD109^-/- mice had a poor ability to induce cytokine production in ex vivo DC-T cell cocultures with high expression of RUNX3 (runt-related transcription factor 3), resulting in suppression of Th2 differentiation. Adoptive transfer of bone marrow-derived CD109^-/- DCs loaded with house dust mite failed to develop AHR and eosinophilic inflammation. Finally, administration of monoclonal anti-CD109 antibody reduced airway eosinophils and significantly decreased AHR. Our results suggest the involvement of CD109 in asthma pathogenesis. CD109 is a novel therapeutic target for asthma.

New insights into autophagy in inflammatory subtypes of asthma

Asthma is a heterogeneous airway disease characterized by airway inflammation and hyperresponsiveness. Autophagy is a self-degrading process that helps maintain cellular homeostasis. Dysregulation of autophagy is involved in the pathogenesis of many diseases. In the context of asthma, autophagy has been shown to be associated with inflammation, airway remodeling, and responsiveness to drug therapy. In-depth characterization of the role of autophagy in asthma can enhance the understanding of the pathogenesis, and provide a theoretical basis for the development of new biomarkers and targeted therapy for asthma. In this article, we focus on the relationship of autophagy and asthma, and discuss its implications for asthma pathogenesis and treatment.

The Role of Macrophage Autophagy in Asthma: A Novel Therapeutic Strategy

Asthma is a chronic respiratory disease frequently associated with airway inflammation and remodeling. The development of asthma involves various inflammatory phenotypes that impact therapeutic effects, and macrophages are master innate immune cells in the airway that exert diverse functions including phagocytosis, antigen presentation, and pathogen clearance, playing an important role in the pathogeneses of asthma. Recent studies have indicated that autophagy of macrophages affects polarization of phenotype and regulation of inflammation, which implies that regulating autophagy of macrophages may be a potential strategy for the treatment of asthma. Thus, this review summarizes the signaling pathways and effects of macrophage autophagy in asthma, which will provide a tactic for the development of novel targets for the treatment of this disease.

Mitochondrial VDAC1: A Potential Therapeutic Target of Inflammation-Related Diseases and Clinical Opportunities

The multifunctional protein, voltage-dependent anion channel 1 (VDAC1), is located on the mitochondrial outer membrane. It is a pivotal protein that maintains mitochondrial function to power cellular bioactivities via energy generation. VDAC1 is involved in regulating energy production, mitochondrial oxidase stress, Ca²⁺ transportation, substance metabolism, apoptosis, mitochondrial autophagy (mitophagy), and many other functions. VDAC1 malfunction is associated with mitochondrial disorders that affect inflammatory responses, resulting in an up-regulation of the body’s defensive response to stress stimulation. Overresponses to inflammation may cause chronic diseases. Mitochondrial DNA (mtDNA) acts as a danger signal that can further trigger native immune system activities after its secretion. VDAC1 mediates the release of mtDNA into the cytoplasm to enhance cytokine levels by activating immune responses. VDAC1 regulates mitochondrial Ca²⁺ transportation, lipid metabolism and mitophagy, which are involved in inflammation-related disease pathogenesis. Many scientists have suggested approaches to deal with inflammation overresponse issues via specific targeting therapies. Due to the broad functionality of VDAC1, it may become a useful target for therapy in inflammation-related diseases. The mechanisms of VDAC1 and its role in inflammation require further exploration. We comprehensively and systematically summarized the role of VDAC1 in the inflammatory response, and hope that our research will lead to novel therapeutic strategies that target VDAC1 in order to treat inflammation-related disorders.

Interactions of Autophagy and the Immune System in Health and Diseases

Autophagy is a highly conserved process that utilizes lysosomes to selectively degrade a variety of intracellular cargo, thus providing quality control over cellular components and maintaining cellular regulatory functions. Autophagy is triggered by multiple stimuli ranging from nutrient starvation to microbial infection. Autophagy extensively shapes and modulates the inflammatory response, the concerted action of immune cells, and secreted mediators aimed to eradicate a microbial infection or to heal sterile tissue damage. Here, we first review how autophagy affects innate immune signaling, cell-autonomous immune defense, and adaptive immunity. Then, we discuss the role of non-canonical autophagy in microbial infections and inflammation. Finally, we review how crosstalk between autophagy and inflammation influences infectious, metabolic, and autoimmune disorders.

Obesity-Mediated Immune Modulation: One Step Forward, (Th)2 Steps Back

Over the past decades, the relationship between the immune system and metabolism has become a major research focus. In this arena of immunometabolism the capacity of adipose tissue to secrete immunomodulatory molecules, including adipokines, within the underlying low-grade inflammation during obesity brought attention to the impact obesity has on the immune system. Adipokines, such as leptin and adiponectin, influence T cell differentiation into different T helper subsets and their activation during immune responses. Furthermore, within the cellular milieu of adipose tissue nutrient availability regulates differentiation and activation of T cells and changes in cellular metabolic pathways. Upon activation, T cells shift from oxidative phosphorylation to oxidative glycolysis, while the differential signaling of the kinase mammalian target of rapamycin (mTOR) and the nuclear receptor PPARγ, amongst others, drive the subsequent T cell differentiation. While the mechanisms leading to a shift from the typical type 2-dominated milieu in lean people to a Th1-biased pro-inflammatory environment during obesity are the subject of extensive research, insights on its impact on peripheral Th2-dominated immune responses become more evident. In this review, we will summarize recent findings of how Th2 cells are metabolically regulated during obesity and malnutrition, and how these states affect local and systemic Th2-biased immune responses.