Asthmatic lung fibroblasts promote type 2 immune responses via endoplasmic reticulum stress response dependent thymic stromal lymphopoietin secretion

Increased intracellular stress responses and decreased KLF2 in adult patients with atopic dermatitis

Atopic dermatitis (AD) is prone to exacerbations in response to various triggering factors and flare-ups after remission. We searched for molecules associated with relapse/exacerbation of AD among molecules with altered gene expression in the skin of patients with AD. Microarray analyses were performed on lesional and nonlesional skin of adolescent or adult patients with recalcitrant AD and healthy controls. Five chaperones involved in intracellular stress responses, namely heat shock protein family A (Hsp70) member 9 (HSPA9), heat shock protein 90 beta family member 1 (HSP90B1), calnexin (CANX), malectin (MLEC; endoplasmic reticulum-associated degradation), and heat shock protein family D (Hsp60) member 1 (HSPD1), were consistently upregulated in involved and uninvolved skin of patients with AD. Damage-associated molecular patterns were upregulated in involved skin. KLF transcription factor 2 (KLF2) was decreased in involved skin and exhibited a decreasing trend in uninvolved skin of patients with AD. CD4(+)/CD8(+) double-positive cells (1.4% of T cells) were detected in lesions with declined KLF2 levels. WNT inhibitory factor 1 (WIF1) was downregulated in involved skin. Prolactin-induced protein was upregulated in only uninvolved skin of patients with AD. We found increased intracellular stress responses and decreased expression of KLF2 in the skin of patients with AD. Multifactorial genetic diseases, such as asthma, inflammatory bowel disease, type 2 diabetes, and rheumatoid arthritis, are associated with intracellular stress. Intracellular abnormalities may also be responsible for AD. Further research on AD may incorporate enhanced intracellular stress response and the decreased expression of KLF2 into the mechanism underlying AD.

Endoplasmic reticulum stress in acute lung injury and pulmonary fibrosis

Pulmonary fibrosis (PF) is a progressive and irreversible lung disease that leads to diminished lung function, respiratory failure, and ultimately death and typically has a poor prognosis, with an average survival time of 2 to 5 years. Related articles suggested that endoplasmic reticulum (ER) stress played a critical role in the occurrence and progression of PF. The ER is responsible for maintaining protein homeostasis. However, factors such as aging, hypoxia, oxidative stress, or inflammation can disrupt this balance, promoting the accumulation of misfolded proteins in the ER and triggering ER stress. To cope with this situation, cells activate the unfolded protein response (UPR). Since acute lung injury (ALI) is one of the key onset events of PF, in this review, we will discuss the role of ER stress in ALI and PF by activating multiple signaling pathways and molecular mechanisms that affect the function and behavior of different cell types, with a focus on epithelial cells, fibroblasts, and macrophages. Linking ER stress to these cell types may broaden our understanding of the mechanisms underlying lung fibrosis and help us target these cells through these mechanisms. The relationship between ER stress and PF is still evolving, and future research will explore new strategies to regulate UPR pathways, providing novel therapeutic targets.

The production, function, and clinical applications of IL-33 in type 2 inflammation-related respiratory diseases

Epithelial-derived IL-33 (Interleukin-33), as a member of alarm signals, is a chemical substance produced under harmful stimuli that can promote innate immunity and activate adaptive immune responses. Type 2 inflammation refers to inflammation primarily mediated by Type 2 helper T cells (Th2), Type 2 innate lymphoid cells (ILC2), and related cytokines. Type 2 inflammation manifests in various forms in the lungs, with diseases such as asthma and chronic obstructive pulmonary disease chronic obstructive pulmonary disease (COPD) closely associated with Type 2 inflammation. Recent research suggests that IL-33 has a promoting effect on Type 2 inflammation in the lungs and can be regarded as an alarm signal for Type 2 inflammation. This article provides an overview of the mechanisms and related targets of IL-33 in the development of lung diseases caused by Type 2 inflammation, and summarizes the associated treatment methods. Analyzing lung diseases from a new perspective through the alarm of Type 2 inflammation helps to gain a deeper understanding of the pathogenesis of these related lung diseases. This, in turn, facilitates a better understanding of the latest treatment methods and potential therapeutic targets for diseases, with the expectation that targeting lL-33 can propose new strategies for disease prevention.

Endoplasmic reticulum stress-induced senescence in human lung fibroblasts

Loss of proteostasis and cellular senescence have been previously established as characteristics of aging; however, their interaction in the context of lung aging and potential contributions to aging-associated lung remodeling remains understudied. In this study, we aimed to characterize endoplasmic reticulum (ER) stress response, cellular senescence, and their interaction in relation to extracellular matrix (ECM) production in lung fibroblasts from young (25-45 yr) and old (>60 yr) humans. Fibroblasts from young and old patients without significant preexisting lung disease were exposed to vehicle, MG132, etoposide, or salubrinal. Afterward, cells and cell lysates or supernatants were analyzed for ER stress, cellular senescence, and ECM changes using protein analysis, proliferation assay, and senescence-associated beta-galactosidase (SA-β-Gal) staining. At baseline, fibroblasts from aging individuals showed increased levels of ER stress (ATF6 and PERK), senescence (p21 and McL-1), and ECM marker (COL1A1) compared to those from young individuals. Upon ER stress induction and etoposide exposure, fibroblasts showed an increase in senescence (SA-β-Gal, p21, and Cav-1), ER stress (PERK), and ECM markers (COL1A1 and LUM) compared to vehicle. Additionally, IL-6 and IL-8 levels were increased in the supernatants of MG132- and etoposide-treated fibroblasts, respectively. Finally, the ER stress inhibitor salubrinal decreased the expression of p21 compared to vehicle and MG132 treatments; however, salubrinal inhibited COL1A1 but not p21 expression in MG132-treated fibroblasts. Our study suggests that ER stress response plays an important role in establishment and maintenance of a senescence phenotype in lung fibroblasts and therefore contributes to altered remodeling in the aging lung.NEW & NOTEWORTHY The current study establishes functional links between endoplasmic reticulum (ER) stress and cellular senescence per se in the specific context of aging human lung fibroblasts. Recognizing that the process of aging per se is complex, modulated by the myriad of lifelong and environmental exposures, it is striking to note that chronic ER stress may play a crucial role in the establishment and maintenance of cellular senescence in lung fibroblasts.

Airway remodelling in asthma and the epithelium: on the edge of a new era

Asthma is a chronic, heterogeneous disease of the airways, often characterised by structural changes known collectively as airway remodelling. In response to environmental insults, including pathogens, allergens and pollutants, the epithelium can initiate remodelling via an inflammatory cascade involving a variety of mediators that have downstream effects on both structural and immune cells. These mediators include the epithelial cytokines thymic stromal lymphopoietin, interleukin (IL)-33 and IL-25, which facilitate airway remodelling through cross-talk between epithelial cells and fibroblasts, and between mast cells and airway smooth muscle cells, as well as through signalling with immune cells such as macrophages. The epithelium can also initiate airway remodelling independently of inflammation in response to the mechanical stress present during bronchoconstriction. Furthermore, genetic and epigenetic alterations to epithelial components are believed to influence remodelling. Here, we review recent advances in our understanding of the roles of the epithelium and epithelial cytokines in driving airway remodelling, facilitated by developments in genetic sequencing and imaging techniques. We also explore how new and existing therapeutics that target the epithelium and epithelial cytokines could modify airway remodelling.