Advances in cellular senescence in idiopathic pulmonary fibrosis (Review)

Treatment of Bleomycin-induced Pulmonary Fibrosis by Intratracheal Instillation Administration of Ellagic Acid-Loaded Chitosan Nanoparticles

Idiopathic Pulmonary Fibrosis (IPF) is a rare and serious chronic interstitial lung disease that may endanger the lives of patients. The median survival time of patients with idiopathic pulmonary fibrosis is short, and the mortality rate is higher than that of many types of cancer. At present, pirfenidone (PFD) and nintedanib (NDNB) have been approved by FDA for IPF, but they can only delay the process of pulmonary fibrosis and cannot cure the disease. Therefore, it is urgent to develop other drugs with the effect of improving pulmonary fibrosis. Ellagic acid (EA) can inhibit the Wnt-signaling pathway and has an effect in treating pulmonary fibrosis induced by bleomycin (BLM) in mice. However, its solubility is poor, resulting in its low bioavailability and limited therapeutic benefits, so its clinical application has been limited. Herein, based on the characteristics of nano-drug lung delivery system, chitosan (CS) was selected as the carrier, and ellagic acid-loaded chitosan nanoparticles (EA-CS-NPs) were prepared by ionic gelation method. The EE% and DL% of prepared EA-CS-NPs was 73.73 ± 4.52% and 6.23 ± 1.09%, the particle size was 119.6 ± 5.51 nm (PDI = 0.234 ± 0.017), the zeta potential was 29.833 ± 0.503 mV. The morphology of the nanoparticles was observed by TEM microscope, which was round, uniform dispersion, indicating that the preparation process is stable and feasible. The toxicity experiment showed that EA-CS-NPs maintained 80% cell viability, significantly higher than that of the NDNB group, indicating lower toxicity and better inhibitory effects on TGF-β1-stimulated MLg and NIH-3T3 cells. Wound healing assay results showed that the inhibitory effect of EA-CS-NPs on cell migration was more pronounced than that of EA in the same amount of EA-containing drugs. Drug uptake experiments revealed that EA-CS-NPs significantly enhanced drug uptake in MLg and NIH-3T3 cells. In vivo, Cy7-CS-NPs exhibited higher fluorescence intensity in rat lungs compared to Cy7 solution, indicating better lung retention. The in vivo efficacy test showed that compared with the EA group, EA-CS-NPs could better reduce the area of pulmonary fibrosis and collagen deposition, improve lung function, and have a longer retention time in the lung. In summary, our results revealed that EA-CS-NPs may be a good choice for the treatment of pulmonary fibrosis.

Crosstalk between ROS-inflammatory gene expression axis in the progression of lung disorders

A significant number of deaths and disabilities worldwide are brought on by inflammatory lung diseases. Many inflammatory lung disorders, including chronic respiratory emphysema, resistant asthma, resistance to steroids, and coronavirus-infected lung infections, have severe variants for which there are no viable treatments; as a result, new treatment alternatives are needed. Here, we emphasize how oxidative imbalance contributes to the emergence of provocative lung problems that are challenging to treat. Endogenic antioxidant systems are not enough to avert free radical-mediated damage due to the induced overproduction of ROS. Pro-inflammatory mediators are then produced due to intracellular signaling events, which can harm the tissue and worsen the inflammatory response. Overproduction of ROS causes oxidative stress, which causes lung damage and various disease conditions. Invasive microorganisms or hazardous substances that are inhaled repeatedly can cause an excessive amount of ROS to be produced. By starting signal transduction pathways, increased ROS generation during inflammation may cause recurrent DNA damage and apoptosis and activate proto-oncogenes. This review provides information about new targets for conducting research in related domains or target factors to prevent, control, or treat such inflammatory oxidative stress-induced inflammatory lung disorders.

Aging Lung: Molecular Drivers and Impact on Respiratory Diseases-A Narrative Clinical Review

The aging process significantly impacts lung physiology and is a major risk factor for chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, and non-IPF interstitial lung fibrosis. This narrative clinical review explores the molecular and biochemical hallmarks of aging, such as oxidative stress, telomere attrition, genomic instability, epigenetic modifications, proteostasis loss, and impaired macroautophagy, and their roles in lung senescence. Central to this process are senescent cells, which, through the senescence-associated secretory phenotype (SASP), contribute to chronic inflammation and tissue dysfunction. The review highlights parallels between lung aging and pathophysiological changes in respiratory diseases, emphasizing the role of cellular senescence in disease onset and progression. Despite promising research into modulating aging pathways with interventions like caloric restriction, mTOR inhibitors, and SIRT1 activators, clinical evidence for efficacy in reversing or preventing age-related lung diseases remains limited. Understanding the interplay between aging-related mechanisms and environmental factors, such as smoking and pollution, is critical for developing targeted therapies. This review underscores the need for future studies focusing on therapeutic strategies to mitigate aging's detrimental effects on lung health and improve outcomes for patients with chronic respiratory conditions.

Senescence and tissue fibrosis: opportunities for therapeutic targeting

Cellular senescence is a key hallmark of aging. It has now emerged as a key mediator in normal tissue turnover and is associated with a variety of age-related diseases, including organ-specific fibrosis and systemic sclerosis (SSc). This review discusses the recent evidence of the role of senescence in tissue fibrosis, with an emphasis on SSc, a systemic autoimmune rheumatic disease. We discuss the physiological role of these cells, their role in fibrosis, and that targeting these cells specifically could be a new therapeutic avenue in fibrotic disease. We argue that targeting senescent cells, with senolytics or senomorphs, is a viable therapeutic target in fibrotic diseases which remain largely intractable.

Cellular and Molecular Genetic Mechanisms of Lung Fibrosis Development and the Role of Vitamin D: A Review

Idiopathic pulmonary fibrosis remains a relevant problem of the healthcare system with an unfavorable prognosis for patients due to progressive fibrous remodeling of the pulmonary parenchyma. Starting with the damage of the epithelial lining of alveoli, pulmonary fibrosis is implemented through a cascade of complex mechanisms, the crucial of which is the TGF-β/SMAD-mediated pathway, involving various cell populations. Considering that a number of the available drugs (pirfenidone and nintedanib) have only limited effectiveness in slowing the progression of fibrosis, the search and justification of new approaches aimed at regulating the immune response, cellular aging processes, programmed cell death, and transdifferentiation of cell populations remains relevant. This literature review presents the key modern concepts concerning molecular genetics and cellular mechanisms of lung fibrosis development, based mainly on in vitro and in vivo studies in experimental models of bleomycin-induced pulmonary fibrosis, as well as the latest data on metabolic features, potential targets, and effects of vitamin D and its metabolites.

Rheumatoid arthritis extra-articular lung disease: new insights on pathogenesis and experimental drugs

INTRODUCTION

Pulmonary involvement is one of the most common extra-articular manifestations of rheumatoid arthritis (RA), a systemic inflammatory disease characterized by joint swelling and tenderness. All lung compartments can be interested in the course of RA, including parenchyma, airways, and, more rarely, pleura and vasculature.

AREAS COVERED

The aim of this paper is to review the main RA lung manifestations, focusing on pathogenesis, clinical and therapeutic issues of RA-related interstitial lung disease (ILD). Despite an increasing number of studies in the last years, pathogenesis of RA-ILD remains largely debated and the treatment of RA patients with lung involvement is still challenging in these patients.

EXPERT OPINION

Management of RA-ILD is largely based on expert-opinion. Due to the broad clinical manifestations, including both joints and pulmonary involvement, multidisciplinary discussion, including rheumatologist and pulmonologist, is essential, not only for diagnosis, but also to evaluate the best therapeutic approach and follow-up. In fact, the coexistence of different lung manifestations may influence the treatment response and safety. The identification of biomarkers and risk-factors for an early identification of RA patients at risk of developing ILD remains a need that still needs to be fulfilled, and that will require further investigation in the next years.

Exploring the effects of Saorilao-4 on the gut microbiota of pulmonary fibrosis model rats based on 16S rRNA sequencing

AIMS

Pulmonary fibrosis (PF) is a progressive and incurable lung disease for which treatment options are limited. Here, we aimed to conduct an exploratory study on the effects of the Mongolian medicine Saorilao-4 (SRL) on the gut microbiota structure, species abundance, and diversity of a rat PF model as well as the mechanisms underlying such effects.

METHODS AND RESULTS

Rat fecal samples were analyzed using 16S rRNA sequencing technology. Bioinformatic and correlation analyses were performed on microbiota data to determine significant associations. SRL substantially attenuated the adverse effects exerted by PF on the structure and diversity of gut microbiota while regulating its alpha and beta diversities. Linear discriminant analysis effect size enabled the identification of 62 differentially abundant microbial taxa. Gut microbiota abundance analysis revealed that SRL significantly increased the relative abundance of bacterial phyla such as Firmicutes and Bacteroidetes. Moreover, SRL increased the proportion of beneficial bacteria, such as Lactobacillus and Bifidobacteriales, decreased the proportion of pathogenic bacteria, such as Rikenellaceae, and balanced the gut microbiota by regulating metabolic pathways.

CONCLUSIONS

SRL may attenuate PF by regulating gut microbiota. This exploratory study establishes the groundwork for investigating the metagenomics of PF.

Sirtuins and Cellular Senescence in Patients with Idiopathic Pulmonary Fibrosis and Systemic Autoimmune Disorders

The sirtuin family is a heterogeneous group of proteins that play a critical role in many cellular activities. Several degenerative diseases have recently been linked to aberrant sirtuin expression and activity because of the involvement of sirtuins in maintaining cell longevity and their putative antiaging function. Idiopathic pulmonary fibrosis and progressive pulmonary fibrosis associated with systemic autoimmune disorders are severe diseases characterized by premature and accelerated exhaustion and failure of alveolar type II cells combined with aberrant activation of fibroblast proliferative pathways leading to dramatic destruction of lung architecture. The mechanisms underlying alveolar type II cell exhaustion in these disorders are not fully understood. In this review, we have focused on the role of sirtuins in the pathogenesis of idiopathic and secondary pulmonary fibrosis and their potential as biomarkers in the diagnosis and management of fibrotic interstitial lung diseases.

Redox organization of living systems

Redox organization governs an underlying simplicity in living systems. Critically, redox reactions enable the essential characteristics of life: extraction of energy from the environment, use of energy to support metabolic and structural organization, use of dynamic redox responses to defend against environmental threats, and use of redox mechanisms to direct differentiation of cells and organ systems essential for reproduction. These processes are sustained through a redox context in which electron donor/acceptor couples are poised at substantially different steady-state redox potentials, some with relatively reducing steady states and others with relatively oxidizing steady states. Redox-sensitive thiols of the redox proteome, as well as low molecular weight redox-active molecules, are maintained individually by the kinetics of oxidation-reduction within this redox system. Recent research has revealed opposing network interactions of the metallome, redox proteome, metabolome and transcriptome, which appear to be an evolved redox response structure to maintain stability of an organism in the presence of variable oxidative environments. Considerable opportunity exists to improve human health through detailed understanding of these redox networks so that targeted interventions can be developed to support new avenues for redox medicine.

Pulmonary Fibrosis and Diabetes Mellitus: Two coins with the same face

Idiopathic pulmonary fibrosis (IPF) constitutes a long-term disease with a complex pathophysiology composed of multiple molecular actors that lead to the deposition of extracellular matrix, the loss of pulmonary function and ultimately the patient's death. Despite the approval of pirfenidone and nintedanib for the treatment of the disease, lung transplant is the only long-term solution to fully recover the respiratory capacity and gain quality of life. One of the risk factors for the development of IPF is the pre-existing condition of diabetes mellitus. Both, IPF and diabetes mellitus, share similar pathological damage mechanisms, including inflammation, endoplasmic reticulum stress, mitochondrial failure, oxidative stress, senescence and signaling from glycated proteins through receptors. In this critical review article, we provide information about this interrelationship, examining molecular mediators that play an essential role in both diseases and identify targets of interest for the development of potential drugs. We review the findings of clinical trials examining the progression of IPF and how novel molecules may be used to stop this process. The results highlight the importance of early detection and addressing multiple therapeutic targets simultaneously to achieve better therapeutic efficacy and potentially reverse lung fibrosis.

Unraveling the interplay between vital organelle stress and oxidative stress in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease characterized by excessive accumulation of extracellular matrix, leading to irreversible fibrosis. Emerging evidence suggests that endoplasmic reticulum (ER) stress, mitochondrial stress, and oxidative stress pathways play crucial roles in the pathogenesis of IPF. ER stress occurs when the protein folding capacity of the ER is overwhelmed, triggering the unfolded protein response (UPR) and contributing to protein misfolding and cellular stress in IPF. Concurrently, mitochondrial dysfunction involving dysregulation of key regulators, including PTEN-induced putative kinase 1 (PINK1), Parkin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and sirtuin 3 (SIRT3), disrupts mitochondrial homeostasis and impairs cellular energy metabolism. This leads to increased reactive oxygen species (ROS) production, release of pro-fibrotic mediators, and activation of fibrotic pathways, exacerbating IPF progression. The UPR-induced ER stress further disrupts mitochondrial metabolism, resulting in altered mitochondrial mechanisms that increase the generation of ROS, resulting in further ER stress, creating a feedback loop that contributes to the progression of IPF. Oxidative stress also plays a pivotal role in IPF, as ROS-mediated activation of TGF-β, NF-κB, and MAPK pathways promotes inflammation and fibrotic responses. This review mainly focuses on the links between ER stress, mitochondrial dysfunctions, and oxidative stress with different signaling pathways involved in IPF. Understanding these mechanisms and targeting key molecules within these pathways may offer promising avenues for intervention.

LEF1 isoforms regulate cellular senescence and aging

The study of aging and its mechanisms, such as cellular senescence, has provided valuable insights into age-related pathologies, thus contributing to their prevention and treatment. The current abundance of high-throughput data combined with the surge of robust analysis algorithms has facilitated novel ways of identifying underlying pathways that may drive these pathologies. For the purpose of identifying key regulators of lung aging, we performed comparative analyses of transcriptional profiles of aged versus young human subjects and mice, focusing on the common age-related changes in the transcriptional regulation in lung macrophages, T cells, and B immune cells. Importantly, we validated our findings in cell culture assays and human lung samples. Our analysis identified lymphoid enhancer binding factor 1 (LEF1) as an important age-associated regulator of gene expression in all three cell types across different tissues and species. Follow-up experiments showed that the differential expression of long and short LEF1 isoforms is a key regulatory mechanism of cellular senescence. Further examination of lung tissue from patients with idiopathic pulmonary fibrosis, an age-related disease with strong ties to cellular senescence, revealed a stark dysregulation of LEF1. Collectively, our results suggest that LEF1 is a key factor of aging, and its differential regulation is associated with human and murine cellular senescence.

Cellular Senescence: A Troy Horse in Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a chronic interstitial lung disease characterized by myofibroblast abnormal activation and extracellular matrix deposition. However, the pathogenesis of PF remains unclear, and treatment options are limited. Epidemiological studies have shown that the average age of PF patients is estimated to be over 65 years, and the incidence of the disease increases with age. Therefore, PF is considered an age-related disease. A preliminary study on PF patients demonstrated that the combination therapy of the anti-senescence drugs dasatinib and quercetin improved physical functional indicators. Given the global aging population and the role of cellular senescence in tissue and organ aging, understanding the impact of cellular senescence on PF is of growing interest. This article systematically summarizes the causes and signaling pathways of cellular senescence in PF. It also objectively analyzes the impact of senescence in AECs and fibroblasts on PF development. Furthermore, potential intervention methods targeting cellular senescence in PF treatment are discussed. This review not only provides a strong theoretical foundation for understanding and manipulating cellular senescence, developing new therapies to improve age-related diseases, and extending a healthy lifespan but also offers hope for reversing the toxicity caused by the massive accumulation of senescence cells in humans.

The Role of Macrophages in Connective Tissue Disease-Associated Interstitial Lung Disease: Focusing on Molecular Mechanisms and Potential Treatment Strategies

Connective tissue disease-associated interstitial lung disease (CTD-ILD) is a severe manifestation of CTD that leads to significant morbidity and mortality. Clinically, ILD can occur in diverse CTDs. Pathologically, CTD-ILD is characterized by various histologic patterns, such as nonspecific interstitial pneumonia, organizing pneumonia, and usual interstitial pneumonia. Abnormal immune system responses have traditionally been instrumental in its pathophysiology, and various changes in immune cells have been described, especially in macrophages. This article first briefly overviews the epidemiology, clinical characteristics, impacts, and histopathologic changes associated with CTD-ILD. Next, it summarizes the roles of various signaling pathways in macrophages or products of macrophages in ILD, helped by insights gained from animal models. In the following sections, this review returns to studies of macrophages in CTD-ILD in humans for an overall picture of the current understanding. Finally, we direct attention to potential therapies targeting macrophages in CTD-ILD in investigation or in clinical trials, as well as the future directions regarding macrophages in the context of CTD-ILD. Although the field of macrophages in CTD-ILD is still in its infancy, several lines of evidence suggest the potential of this area.