Fenbendazole Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice via Suppression of Fibroblast-to-Myofibroblast Differentiation

Mechanisms and Therapeutic Potential of Myofibroblast Transformation in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible, and fatal disease with an increasing incidence and limited therapeutic options. It is characterized by the formation and deposition of excess extracellular matrix proteins resulting in the gradual replacement of normal lung architecture by fibrous tissue. The cellular and molecular mechanism of IPF has not been fully understood. A hallmark in IPF is pulmonary fibroblast to myofibroblast transformation (FMT). During excessive lung repair upon exposure to harmful stimuli, lung fibroblasts transform into myofibroblasts under stimulation of cytokines, chemokines, and vesicles from various cells. These mediators interact with lung fibroblasts, initiating multiple signaling cascades, such as TGFβ1, MAPK, Wnt/β-catenin, NF-κB, AMPK, endoplasmic reticulum stress, and autophagy, contributing to lung FMT. Furthermore, single-cell transcriptomic analysis has revealed significant heterogeneity among lung myofibroblasts, which arise from various cell types and are adapted to the altered microenvironment during pathological lung repair. This review provides an overview of recent research on the origins of lung myofibroblasts and the molecular pathways driving their formation, with a focus on the interactions between lung fibroblasts and epithelial cells, endothelial cells, and macrophages in the context of lung fibrosis. Based on these molecular insights, targeting the lung FMT could offer promising avenues for the treatment of IPF.

PDK2-enhanced glycolysis aggravates fibrosis via IL11 signaling pathway in Graves' orbitopathy

Objectives

Transforming growth factor β1 (TGFβ1)-interleukin 11 (IL11) is a newly found critical signaling pathway in fibrotic diseases such as Graves' orbitopathy (GO). It has now been confirmed that enhanced glycolysis plays a key role in the pathogenesis of GO. However, little is known about the relationship between glycolysis and IL11-mediated fibrosis in GO. This study aimed to identify the relationship between glycolysis and TGFβ1-IL11 signaling pathway and investigate the role of IL11 in glycolysis-facilitated fibrosis in GO.

Methods

Orbital connective tissues were collected from GO and control patients. Primary orbital fibroblasts (OFs) were cultured from clinical tissues. Patient-derived xenografts were established via intraorbital transplantation of GO orbital tissue in humanized NCG mice. Protein levels were measured using Capillary Western Immunoassay (WES). Small interfering RNA (siRNA) was used to construct transfected OF strains. Lactate production was measured to assess glycolysis status. Animal models were assessed by T2-weighted magnetic resonance (MR) scan. Immunohistochemistry staining was applied to patients' orbital connective tissues.

Results

Orbital connective tissues were collected from GO patients. Immunohistochemical (IHC) staining of GO tissues revealed the phenomenon of pyruvate dehydrogenase kinase 2 (PDK2)-enhanced glycolysis and upregulated IL11-IL11Rα pathway. In vitro experiments showed successful induction of fibrosis of patient-derived orbital fat/connective tissues, which could be alleviated by dichloroacetic acid (DCA). MRI images and analysis of hematoxylin and eosin (HE) and Masson-stained section demonstrated enhanced glycolysis in GO, facilitating fibrosis of the orbital tissue. Targeting PDK2 decreased IL11 expression to suppress fibrosis. In vivo experiment confirmed anti-fibrotic effect of inhibition of glycolysis.

Conclusions

PDK2-enhanced glycolysis exacerbates fibrosis via IL11-IL11Rα signaling pathway, shedding light on a potential therapeutic role of metabolic modulators such as DCA in GO treatment.

The role of the cytoskeleton in fibrotic diseases

Fibrosis is the process whereby cells at a damaged site are transformed into fibrotic tissue, comprising fibroblasts and an extracellular matrix rich in collagen and fibronectin, following damage to organs or tissues that exceeds their repair capacity. Depending on the affected organs or tissues, fibrosis can be classified into types such as pulmonary fibrosis, hepatic fibrosis, renal fibrosis, and cardiac fibrosis. The primary pathological features of fibrotic diseases include recurrent damage to normal cells and the abnormal activation of fibroblasts, leading to excessive deposition of extracellular matrix and collagen in the intercellular spaces. However, the etiology of certain specific fibrotic diseases remains unclear. Recent research increasingly suggests that the cytoskeleton plays a significant role in fibrotic diseases, with structural changes in the cytoskeleton potentially influencing the progression of organ fibrosis. This review examines cytoskeletal remodeling and its impact on the transformation or activation of normal tissue cells during fibrosis, potentially offering important insights into the etiology and therapeutic strategies for fibrotic diseases.

Targeting reprogrammed metabolism as a therapeutic approach for respiratory diseases

Metabolic reprogramming underlies the etiology and pathophysiology of respiratory diseases such as asthma, idiopathic pulmonary fibrosis (IPF), and chronic obstructive pulmonary disease (COPD). The dysregulated cellular activities driving airway inflammation and remodelling in these diseases have reportedly been linked to aberrant shifts in energy-producing metabolic pathways: glycolysis and oxidative phosphorylation (OXPHOS). The rewiring of glycolysis and OXPHOS accompanying the therapeutic effects of many clinical compounds and natural products in asthma, IPF, and COPD, supports targeting metabolism as a therapeutic approach for respiratory diseases. Correspondingly, inhibiting glycolysis has largely attested effective against experimental asthma, IPF, and COPD. However, modulating OXPHOS and its supporting catabolic pathways like mitochondrial pyruvate catabolism, fatty acid β-oxidation (FAO), and glutaminolysis for these respiratory diseases remain inconclusive. An emerging repertoire of metabolic enzymes are also interconnected to these canonical metabolic pathways that similarly possess therapeutic potential for respiratory diseases. Taken together, this review highlights the urgent demand for future studies to ascertain the role of OXPHOS in different respiratory diseases, under different stimulatory conditions, and in different cell types. While this review provides strong experimental evidence in support of the inhibition of glycolysis for asthma, IPF, and COPD, further verification by clinical trials is definitely required.

Tuftelin1 drives experimental pulmonary fibrosis progression by facilitating stress fiber assembly

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease (ILD) with unknown etiology, characterized by sustained damage repair of epithelial cells and abnormal activation of fibroblasts, the underlying mechanism of the disease remains elusive.

METHODS

To evaluate the role of Tuftelin1 (TUFT1) in IPF and elucidate its molecular mechanism. We investigated the level of TUFT1 in the IPF and bleomycin-induced mouse models and explored the influence of TUFT1 deficiency on pulmonary fibrosis. Additionally, we explored the effect of TUFT1 on the cytoskeleton and illustrated the relationship between stress fiber and pulmonary fibrosis.

RESULTS

Our results demonstrated a significant upregulation of TUFT1 in IPF and the bleomycin (BLM)-induced fibrosis model. Disruption of TUFT1 exerted inhibitory effects on pulmonary fibrosis in both in vivo and in vitro. TUFT1 facilitated the assembly of microfilaments in A549 and MRC-5 cells, with a pronounced association between TUFT1 and Neuronal Wiskott-Aldrich syndrome protein (N-WASP) observed during microfilament formation. TUFT1 can promote the phosphorylation of tyrosine residue 256 (Y256) of the N-WASP (pY256N-WASP). Furthermore, TUFT1 promoted transforming growth factor-β1 (TGF-β1) induced fibroblast activation by increasing nuclear translocation of pY256N-WASP in fibroblasts, while wiskostatin (Wis), an N-WASP inhibitor, suppressed these processes.

CONCLUSIONS

Our findings suggested that TUFT1 plays a critical role in pulmonary fibrosis via its influence on stress fiber, and blockade of TUFT1 effectively reduces pro-fibrotic phenotypes. Pharmacological targeting of the TUFT1-N-WASP axis may represent a promising therapeutic approach for pulmonary fibrosis.

Promising small molecule anti-fibrotic agents: Newly developed or repositioned drugs targeting myofibroblast transdifferentiation

Fibrosis occurs in all organs and tissues except the brain, and its progression leads to dysfunction of affected organs. Fibrosis-induced organ dysfunction results from the loss of elasticity, strength, and functionality of tissues due to the extracellular matrix secreted by myofibroblasts that express smooth muscle-type actin as a marker. Myofibroblasts, which play a major role in fibrosis, were once thought to originate exclusively from activated fibroblasts; however, it is now clear that myofibroblasts are diverse in origin, from epithelial cells, endothelial cells, adipocytes, macrophages, and other cells. Fibrosis of vital organs, such as the heart, lungs, kidneys, and liver, is a serious chronic disease that ultimately leads to death. Currently, anti-cancer drugs have made remarkable progress, as evidenced by the development of many molecular-targeted drugs, and are making a significant contribution to improving the prognosis of cancer treatment. However, the development of anti-fibrotic agents, which also play an important role in prognosis, has lagged. In this review, the current knowledge regarding myofibroblasts is summarized, with particular attention given to their origin and transdifferentiation signaling pathways (e.g., TGF-β, Wnt/β-catenin, YAP/TAZ and AMPK signaling pathways). The development of new small molecule anti-fibrotic agents and the repositioning of existing drugs targeting myofibroblast transdifferentiation are discussed.