p62-dependent autophagy in airway smooth muscle cells regulates metabolic reprogramming and promotes airway remodeling

Glycolysis in asthma: Its role and potential as a diagnostic or therapeutic target

Asthma is a heterogeneous disease characterized by chronic airway inflammation and hyperresponsiveness. A number of immune cells are involved in asthma pathogenesis, such as eosinophils, mast cells, T lymphocytes and neutrophils, as well as airway epithelial cells. Glycolysis plays a crucial role in glucose metabolism, and serves as a bridge between metabolic and inflammatory dysfunction. Research has found that abnormal glycolytic metabolism in various immune cells may contribute to the pathogenesis of asthma by inducing dysregulation in congenital and adaptive immune responses. Therefore, the inhibition of glycolysis can be a viable approach to prevent airway inflammation in asthma. The present study reviews the relationship between glycolysis and inflammatory cells in different asthma subtypes, and its potential therapeutic significance.

Elevated aerobic glycolysis driven by p62-mTOR axis promotes arsenic-induced oncogenic phenotypes in human mammary epithelial cells

Chronic arsenic exposure is considered to increase the risk of breast cancer. p62 is a multifunctional adaptor protein that controls myriad cellular processes and is overexpressed in breast cancer tissues. Although previous studies have indicated the involvement of p62 accumulation in arsenic tumorigenesis, the underlying mechanism remains obscure. Here, we found that 0.1 µM or 0.5 µM arsenite exposure for 24 weeks induced oncogenic phenotypes in human mammary epithelial cells. Elevated aerobic glycolysis, cell proliferation capacity, and activation of p62-mTOR pathway, as indicated by increased protein levels of p62, phosphorylated-mTOR (p-mTOR) and hypoxia-inducible factor 1α (HIF1α), were observed in chronically arsenite-exposed cells, and of note in advance of the onset of oncogenic phenotypes. Moreover, p62 silencing inhibited acquisition of oncogenic phenotypes in arsenite-exposed cells. The protein levels of p-mTOR and HIF1α, as well as aerobic glycolysis and cell proliferation, were suppressed by p62 knockdown. In addition, re-activation of p‑mTOR reversed the inhibitory effects of p62 knockdown. Collectively, our data suggest that p62 exerts an oncogenic role via mTORC1 activation and acts as a key player in glucose metabolism during arsenite-induced malignant transformation, which provides a new mechanistic clue for the arsenite carcinogenesis.

Immunometabolism in the pathogenesis of asthma

Bronchial asthma is a heterogeneous disease characterised by chronic airway inflammation. A variety of immune cells such as eosinophils, mast cells, T lymphocytes, neutrophils and airway epithelial cells are involved in the airway inflammation and airway hyperresponsiveness in asthma pathogenesis, resulting in extensive and variable reversible expiratory airflow limitation. However, the precise molecular mechanisms underlying the allergic immune responses, particularly immunometabolism, remains unclear. Studies have detected enhanced oxidative stress, and abnormal metabolic progresses of glycolysis, fatty acid and amino acid in various immune cells, inducing dysregulation of innate and adaptive immune responses in asthma pathogenesis. Immunometabolism mechanisms contain multiple signalling pathways, providing novel therapy targets for asthma. This review summarises the current knowledge on immunometabolism reprogramming in asthma pathogenesis, as well as potential therapy strategies.

Endoplasmic reticulum stress: a vital process and potential therapeutic target in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD), a chronic and progressive disease characterized by persistent respiratory symptoms and progressive airflow obstruction, has attracted extensive attention due to its high morbidity and mortality. Although the understanding of the pathogenesis of COPD has gradually increased because of increasing evidence, many questions regarding the mechanisms involved in COPD progression and its deleterious effects remain unanswered. Recent advances have shown the potential functions of endoplasmic reticulum (ER) stress in causing airway inflammation, emphasizing the vital role of unfolded protein response (UPR) pathways in the development of COPD.

METHODS

A comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original research articles and reviews related to ER stress, UPR, and COPD.

RESULTS

The common causes of COPD, namely cigarette smoke (CS) and air pollutants, induce ER stress through the generation of reactive oxygen species (ROS). UPR promotes mucus secretion and further plays a dual role in the cell apoptosis-autophagy axis in the development of COPD. Existing drug research has indicated the potential of UPR as a therapeutic target for COPD.

CONCLUSIONS

ER stress and UPR activation play significant roles in the etiology, pathogenesis, and treatment of COPD and discuss whether related genes can be used as biomarkers and therapeutic targets.

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.

IL-36 Cytokines: Their Roles in Asthma and Potential as a Therapeutic

Interleukin (IL)-36 cytokines are members of the IL-1 superfamily, which consists of three agonists (IL-36α, IL-36β and IL-36γ) and an IL-36 receptor antagonist (IL-36Ra). IL-36 cytokines are crucial for immune and inflammatory responses. Abnormal levels of IL-36 cytokine expression are involved in the pathogenesis of inflammation, autoimmunity, allergy and cancer. The present study provides a summary of recent reports on IL-36 cytokines that participate in the pathogenesis of inflammatory diseases, and the potential mechanisms underlying their roles in asthma. Abnormal levels of IL-36 cytokines are associated with the pathogenesis of different types of asthma through the regulation of the functions of different types of cells. Considering the important role of IL-36 cytokines in asthma, these may become a potential therapeutic target for asthma treatment. However, existing evidence is insufficient to fully elucidate the specific mechanism underlying the action of IL-36 cytokines during the pathological process of asthma. The possible mechanisms and functions of IL-36 cytokines in different types of asthma require further studies.

Effect of Respiration Training-Assisted Western Medicine Therapy on Activity Tolerance, Pulmonary Function, and Quality of Life of Chronic Obstructive Pulmonary Disease Patients in the Stable Phase

Objective

To explore the effect of respiration training-assisted western medicine therapy on activity tolerance, pulmonary function, and quality of life (QOL) of chronic obstructive pulmonary disease (COPD) patients in the stable phase.

Methods

The medical data of 90 COPD patients in the stable phase treated in the respiratory medicine of our hospital (November 2020-November 2021) were chosen for the retrospective analysis, and the patients were split into group A (n = 45, respiration training-assisted western medicine therapy) and group B (n = 45, western medicine therapy) according to the clinical reception order, so as to record and compare the activity tolerance, lung function, and QOL between the groups after intervention.

Results

Compared with group B after intervention, group A showed greatly longer mean 6-min walking distance, significantly lower St. George's Respiratory Questionnaire (SGRQ) score, significantly higher specific airway conductance (sGAW) and level values of various lung function indicators, and significantly lower level values of airway resistance (RAW) and specific airway resistance (sRAW) (p all<0.001); the total effective rate was significantly higher in group A (p < 0.05).

Conclusion

Respiration training-assisted western medicine therapy is a dependable way to improve the activity tolerance of COPD patients in the stable phase, and such strategy largely improves patients' lung function and QOL. Deeper studies will be helpful to establish a preferable solution for such patients.

TFEB signaling attenuates NLRP3-driven inflammatory responses in severe asthma

BACKGROUND

NLRP3-driven inflammatory responses by circulating and lung-resident monocytes are critical drivers of asthma pathogenesis. Autophagy restrains NLRP3-induced monocyte activation in asthma models. Yet, the effects of autophagy and its master regulator, transcription factor EB (TFEB), on monocyte responses in human asthma remain unexplored. Here, we investigated whether activation of autophagy and TFEB signaling suppress inflammatory monocyte responses in asthmatic individuals.

METHODS

Peripheral blood CD14⁺ monocytes from asthmatic patients (n = 83) and healthy controls (n = 46) were stimulated with LPS/ATP to induce NLRP3 activation with or without the autophagy inducer, rapamycin. ASC specks, caspase-1 activation, IL-1β and IL-18 levels, mitochondrial function, ROS release, and mTORC1 signaling were examined. Autophagy was evaluated by LC3 puncta formation, p62/SQSTM1 degradation and TFEB activation. In a severe asthma (SA) model, we investigated the role of NLRP3 signaling using Nlrp3^-/- mice and/or MCC950 administration, and the effects of TFEB activation using myeloid-specific TFEB-overexpressing mice or administration of the TFEB activator, trehalose.

RESULTS

We observed increased NLRP3 inflammasome activation, concomitant with impaired autophagy in circulating monocytes that correlated with asthma severity. SA patients also exhibited mitochondrial dysfunction and ROS accumulation. Autophagy failed to inhibit NLRP3-driven monocyte responses, due to defective TFEB activation and excessive mTORC1 signaling. NLRP3 blockade restrained inflammatory cytokine release and linked airway disease. TFEB activation restored impaired autophagy, attenuated NLRP3-driven pulmonary inflammation, and ameliorated SA phenotype.

CONCLUSIONS

Our studies uncover a crucial role for TFEB-mediated reprogramming of monocyte inflammatory responses, raising the prospect that this pathway can be therapeutically harnessed for the management of SA.

Autophagy: A Friend or Foe in Allergic Asthma?

Autophagy is a major self-degradative process through which cytoplasmic material, including damaged organelles and proteins, are delivered and degraded in the lysosome. Autophagy represents a dynamic recycling system that produces new building blocks and energy, essential for cellular renovation, physiology, and homeostasis. Principal autophagy triggers include starvation, pathogens, and stress. Autophagy plays also a pivotal role in immune response regulation, including immune cell differentiation, antigen presentation and the generation of T effector responses, the development of protective immunity against pathogens, and the coordination of immunometabolic signals. A plethora of studies propose that both impaired and overactive autophagic processes contribute to the pathogenesis of human disorders, including infections, cancer, atherosclerosis, autoimmune and neurodegenerative diseases. Autophagy has been also implicated in the development and progression of allergen-driven airway inflammation and remodeling. Here, we provide an overview of recent studies pertinent to the biology of autophagy and molecular pathways controlling its activation, we discuss autophagy-mediated beneficial and detrimental effects in animal models of allergic diseases and illuminate new advances on the role of autophagy in the pathogenesis of human asthma. We conclude contemplating the potential of targeting autophagy as a novel therapeutic approach for the management of allergic responses and linked asthmatic disease.