Fibroproliferative mechanisms in organ fibrosis

National Institute On Alcohol Abuse And Alcoholism

Investigators

Linked publications, trials & patents

Abstract

The Section on Fibrotic Disorders (SFD) pursues four major lines of research to achieve our goals as detailed below. 1) Investigating the effects of alcohol misuse in lung health The lungs are frequently exposed to bacteria, viruses, and other environmental factors due to their direct exposure to the environment via inhalation. Therefore, the lungs are particularly susceptible to injuries and inflammatory conditions caused by external factors, making the integrity of lung immunity a critical factor for normal lung physiology. Chronic alcohol drinking dysregulates lung immunity and host defense, making individuals with alcohol use disorder (AUD) more susceptible to developing lung diseases with poor prognoses. Additionally, alcohol misuse makes the lungs more prone to inflammatory conditions while facilitating secondary injuries and fibrosis-prone conditions. Multiple clinical and preclinical pieces of evidence have highlighted that dysregulation of lung immunity may have a central role in the multiple pulmonary complications of AUD. Therefore, understanding the underlying mechanisms by which alcohol consumption disrupts lung immunity in both humans and animal models is essential for conducting clinically and translationally relevant research. Using a data-driven approach through systems biology helps to create hypotheses to identify critical regulators of immune dysregulation in the lungs induced by chronic alcohol consumption. Therefore, our research focuses on investigating the molecular and cellular effects of alcohol drinking on lung immunity in male and female subjects using population-based human lung transcriptomics analysis, and an experimental mouse model of chronic alcohol drinking using the NIAAA alcohol feeding model. Our recent study demonstrated a sexually dimorphic effect of chronic alcohol consumption on dysregulating lung immunity in both humans and mice with immunometabolic alterations. Alcohol dysregulates immune-related genes in the lungs, with a more pronounced effect in males compared to females. This suggests that men may be more vulnerable to alcohol-induced lung immune dysregulation, which could make them more susceptible to secondary lung infections and inflammatory conditions (Pommerolle et al., 2024 PMID: 39024537). Chronic alcohol drinking and a single binge significantly reduced the numbers of various immune cells, including macrophages, eosinophils, and natural killer cells. Alcohol drinking causes significant immunometabolic changes in the lungs, characterized by the upregulation of metabolic pathways and the downregulation of immune system pathways. Furthermore, chronic alcohol consumption resulted in reduced mTOR signaling. Our study demonstrated that mTOR signaling changes might be an upstream regulator of alcohol-induced dysregulation of lung immunity. Our recent study proposed that understanding further the immunometabolic changes induced by alcohol can help develop strategies to mitigate its adverse effects on lung health, particularly in individuals with alcohol use disorder in the future studies. 2) Diagnostic and prognostic biomarker discovery in inflammatory and fibrotic lung diseases Multiple chronic interstitial lung diseases (ILDs) exhibit a common pathological manifestation of progressive pulmonary fibrosis (PPF) and lead to significant mortality and morbidity among affected individuals. Effective management could be achieved by identifying diagnostic and prognostic biomarkers, which could be instrumental to start anti-fibrotic therapy timely to prevent the progression of the disease. Our biomarker discovery research focuses on Hermansky-Pudlak syndrome pulmonary fibrosis (HPSPF) within the spectrum of ILDs since it emerges as a prime candidate for biomarker discovery due to its predictable progression to PF. HPS is an autosomal recessive rare disorder with 11 genetic subtypes. Individuals with HPS-1, HPS-2, HPS-4, or HPS-10 are at risk of developing HPSPF, which is the leading cause of morbidity and premature mortality in HPS. The almost certain development of HPSPF in HPS-1 patients, which intensifies with age and exhibits accelerated onset compared to other PPF variants, underscores the potential of HPS as a platform for early detection and intervention strategies. These unique attributes of HPS provide a unique opportunity to not only anticipate disease advancement but also to explore early therapeutic interventions. Thus, HPSPF linked to HPS-1 offers a valuable framework for uncovering biomarkers that could inform early detection and treatment strategies in PPF considering its similarity to other forms of PF. We conducted two studies using blood samples of HPS patients and healthy volunteer subjects in collaboration with Dr William Gahl's group from the NHGRI. 2A) Untargeted biomarker discovery with an integrative multi-dimensional dataset using longitudinal human data in a rare fibrotic lung disease tracking disease progression The multidimensional nature of HPSPF pathophysiology necessitates a multi-omics strategy to identify biomarkers that capture the dynamic factors driving the fibrotic cascade in the lungs of HPS subjects. In this study, our primary objective was to identify markers that can be used to follow disease progression to HPSPF in HPS-1 subjects. We constructed a multi-dimensional dataset encompassing pulmonary function test (PFT) parameters, age, metabolomics, and multiplex cytokines and chemokines from distinct patient groups (Arif et al.,2025 PMID:40720784). To understand the intricate interplay within and between different datasets, we employed a multi-omics approach coupled with longitudinal analyses. Using an unbiased systems biology approach, we identified that both CCL22 and choline may serve as prognostic blood biomarkers of HPSPF. The findings were validated in an independent cohort from Puerto Rico, confirming the potential of choline and CCL22 as predictive biomarkers for HPSPF. We noted a similarity in the molecular signatures of CCL22 in progressive Idiopathic Pulmonary Fibrosis (IPF) and HPSPF. Furthermore, integrative multi-modal network analysis highlighted the critical role of CCL22 and choline in progressive HPSPF. Importantly, we found that inducible nitric oxide synthase (iNOS) is an upstream regulator of releasing profibrotic mediators (CCL22, CCL24, IL-18, IL1α, IL1β) in HPSPF, suggesting the therapeutic potential of iNOS inhibition in progressive HPSPF and potentially other forms of PF (Arif et al., PMID:40720784). 2B) Targeted biomarker discovery: Blood biomarker function of endocannabinoids in inflammatory and fibrotic lung diseases The endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are synthesized and utilized on demand by multiple cell types in tissues and blood to modulate the cannabinoid receptors that serve autocrine or paracrine functions. Endocannabinoids act through cannabinoid receptor 1 (CB1R) to promote fibrosis in various peripheral organs including the lung. Consequently, peripheral CB1R antagonism has emerged as a potential therapeutic strategy for fibrotic disorders (5). Previously, we found increased AEA levels in the BALF of human IPF (Cinar et al., 2017 PMID:28422760) and HPSPF (Cinar et al, 2021 PMID:34323400) subjects, indicating dysregulated endocannabinoid/CB1R signaling involved in the fibrotic process in the lung microenvironment in PF. In a recent study, we investigated endocannabinoids in longitudinal blood specimens of HPS patients exhibiting progressive HPSPF. We also utilized an animal model of HPSPF to support these findings and further our understanding of the disease mechanism. The longitudinal analysis in a small patient subset of HPSPF suggests that blood anandamide levels begin to increase with the fibrotic lung process at subclinical stages. The increase of blood anandamide correlated with worsening pulmonary function. In alignment with the human data, serum AEA increased early in the fibrotic lung process and remained elevated during the disease progression in the HPS-1 experimental animal model. Experimental treatment with a CB1R antagonist (zevaquenabant) reversed both AEA elevation in serum and fibrosis in lungs, supporting AEA’s utility as a pharmacodynamic biomarker. The findings bridge human and animal data, establishing AEA as a surrogate marker for disease activity and response to targeted therapy (CB1R antagonists), paving the way for potential future clinical trials for HPS pulmonary fibrosis with enabling earlier therapeutic intervention, patient stratification, and real-time monitoring (Cinar et al, 2025 PMID:39841973). Accordingly, our recent studies (Cinar et al, 2025 PMID:39841973, Arif et al.,2025 PMID:40720784) may also endorse zevaquenabant (a dual inhibitor of CB1R/iNOS) as a potential candidate drug for progressive HPSPF, warranting testing in prospective clinical trials. 3) Therapeutic target identification and preclinical drug discovery in inflammatory and fibrotic lung diseases 3A) Identifying CB1R in fibrotic lung macrophages as a therapeutic target for pulmonary fibrosis The level of the endogenous CB1R agonist anandamide (AEA) was significantly increased in bronchoalveolar lavage fluid (BALF) of IPF and HPSPF patients compared with their respective healthy controls, and it was negatively correlated with pulmonary function test parameters (Cinar et al., 2017 PMID:28422760, Cinar et al, 2021 PMID:34323400). As in human PF, AEA levels in BALF were also increased in bleomycin-induced PF mouse models. The increase in the BALF was attenuated by CB1R antagonism, which resulted in the attenuation of PF. All this points to the critical role of AEA and CB1R activation in the fibrotic lung microenvironment in PF. However, cell-specific roles of CB1R in fibrotic lungs have not yet been explored. In our recent study, we identified CB1R-expressing alveolar macrophages (AMs) as a therapeutic target in PF by demonstrating the role of CB1R in profibrotic macrophage activation and inducing a fibrotic microenvironment. Furthermore, we have also shown the prognostic utility of the endocannabinoid AEA in BALF during PF, which is induced by activation of CB1R in AMs (Basu et al., 2025 PMID:40608428). 3B) Identifying new therapeutic modality to improve anti-fibrotic efficacy and safety by inhalational delivery of the hybrid CB1R/iNOS antagonist zevaquenabant Since we identified CB1R expressing AMs as a therapeutic target to promote pulmonary fibrosis, we hypothesized that selective targeting of CB1R locally in the fibrotic lung via pulmonary delivery of peripherally acting CB1R antagonist could provide optimized antifibrotic efficacy while also enhancing systemic safety. We demonstrated that dual targeting of CB1R and iNOS by MRI-1867 (zevaquenabant) via the inhalation route (0.5 mg/kg) provided similar antifibrotic efficacy as systemic administration of a 20 times higher dose (10 mg/kg). Thus, the direct pulmonary delivery of the drug allows a reduction of its effective therapeutic dose, which could further ensure its systemic and CNS safety. This study also demonstrated that MRI-1867 and nintedanib, which is a clinically approved tyrosine kinase receptor inhibitor for IPF and progressive PF, achieved significant antifibrotic efficacy via attenuating both distinct and shared fibroproliferative pathways and differentially altered genes in PF, which are conserved in human IPF lungs. Furthermore, MRI-1867 treatment also attenuated fibrosis and fibrosis mediators in human Precision Cut Lung Slices (hPCLSs). This makes MRI-1867 an emerging candidate for prospective clinical trials in PF. Based on the present findings (Basu et al., 2025 PMID:40608428), pulmonary delivery of zevaquenabant by inhalation would be an emerging therapeutic modality for PF to optimize improved efficacy and safety. 4) Investigating a multi-target therapeutic approach for improving efficacy in fibrotic disorders For multifactorial chronic diseases, such as fibrosis, simultaneous targeting of multiple pathways has been recommended to improve therapeutic efficacy. One of the major challenges in fibrotic lung diseases in human is the lack of predictive and progressive markers to understand the functional relationship between pulmonary function and other biological metrics. This represents a significant gap in the preclinical to clinical translational process. Furthermore, most of the preclinically validated anti-fibrotic drug candidates were found to lack efficacy in clinical trials, suggesting missing links between the animal model and human disease. Although a need for multi-targeted therapies to cure fibrosing lung diseases has been espoused by the experts in fibrosis research, this gap also poses a challenge in designing rational multi-target therapies in fibrosing lung diseases. Most of our understanding of the biochemistry and genomics of PF in humans is linked to the late presentation of this disease. Therefore, the animal model also needs to be informative as to the progressive nature and the critical pathologic pathways in the early, intermediate, and late stages of the disease. Eventually, these studies may require a systems-level understanding of disease initiation and progression in bleomycin-induced PF to maximize translational value in the clinic. To identify that critical fibroproliferative pathways exist in both mouse model of pulmonary fibrosis and human IPF patients, we employed an integrative multiomics approach using a bleomycin-induced PF model to establish a multiomics framework to identify rational therapeutic targets for PF (Arif et al., 2023 PMID:37038090). Our integrative multiomics framework endorses peripheral CB1R antagonism as a rational therapeutic strategy in PF. Furthermore, our study demonstrates that systems biology and systems pharmacology approaches could be employed to identify and prioritize druggable therapeutic targets that regulate multiple pathologic pathways (Arif et al., 2023 PMID:37038090). Previously, we identified simultaneous dual targeting of the cannabinoid receptor 1 (CB1R) and the inducible nitric oxide synthase (iNOS) for inhibition by an in-house generated hybrid inhibitor (MRI-1867, zevaqunabant) that provided improved antifibrotic efficacy in liver (Cinar et al., 2016, PMID:27525312) and different forms of lung fibrosis (Cinar et al., 2017, PMID:28422760, Cinar et al, 2021 PMID:34323400) compared to inhibiting the single target. In a recent study, we demonstrated using a systems pharmacology approach that simultaneous inhibition of CB1R and iNOS by zevaquenabant attenuated multiple fibrotic pathways while effectively reducing pulmonary fibrosis in the both experimental model of pulmonary fibrosis in mice and human derived model systems such as precision cut lung slices (Basu et al., 2025 PMID:40608428). Furthermore, in collaboration with the Section on Medicinal Chemistry (NIAAA), SFD jointly discovered a new class of chemical entities, cannabinoformins, that act as peripherally restricted antagonists of cannabinoid-1 receptors (CB1R) and an AMPK activator Dvoracsko et al., 2023 PMID:37611316). Cannabinoformins may have a promising therapeutic potential for metabolic and fibrotic disorders with polypharmacology.