Regulation of transforming growth factor-β1-driven lung fibrosis by galectin-3

Atropisomerism Observed in Galactose-Based Monosaccharide Inhibitors of Galectin-3 Comprising 2-Methyl-4-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-thione

Galectin-3 (Gal-3) is a carbohydrate binding protein that has been implicated in the development and progression of fibrotic diseases. Proof-of-principal animal models have demonstrated that inhibition of Gal-3 is a potentially viable pathway for the treatment of fibrosis─with small molecule Gal-3 inhibitors advanced into clinical trials. We hereby report the discovery of novel galactose-based monosaccharide Gal-3 inhibitors comprising 2-methyl-4-phenyl-2,4-dihydro-3H-1,2,4-triazole-3-thione (compound 20) and 4-phenyl-4H-1,2,4-triazole (compound 15). Notably, hindered rotation caused by steric interaction between the 3-thione and ortho-trifluoromethyl group of compounds 20, 21 induced formation of thermodynamically stable atropisomers. Distinct X-ray cocrystal structures of 20 and 21 were obtained, which clearly demonstrated that the configuration of 21 proscribes a key halogen bonding σ-hole interaction of 3-chloro with carbonyl oxygen of Gly182, thereby leading to significant loss in potency. Ultimately, 20 and 15 were evaluated in mouse pharmacokinetic studies, and both compounds exhibited oral exposures suitable for further in vivo assessment.

Relative bioavailability and food effect of the galectin-3 inhibitor selvigaltin (GB1211) administered as a tablet in healthy participants (GALBA-1)

PURPOSE

Overexpression of galectin-3, a β-galactoside-binding lectin, is associated with fibrotic diseases and cancer. Selvigaltin is an oral galectin-3 inhibitor, previously administered as a 50 mg capsule. This study aimed to evaluate the relative bioavailability and food effect of selvigaltin as a 100 mg tablet in healthy volunteers.

METHODS

In this single-dose, randomized, three-period, crossover study (GALBA-1; NCT05747573), participants received selvigaltin as a 100 mg tablet (under fasted and fed conditions) or as two 50 mg capsules (under fasted conditions). Primary endpoints included plasma and urine pharmacokinetic (PK) parameters. Secondary endpoints were safety and tolerability.

RESULTS

Of the 13 enrolled participants, 12 completed the study. Under fasted conditions, geometric mean maximum observed plasma concentration (Cmax) and systemic exposure (AUC0─inf) of selvigaltin were 161.0% and 84.0% higher, respectively, after administration of a tablet vs. capsules. Under fed vs. fasted conditions, geometric mean Cmax of the selvigaltin tablet was 20.0% lower, whereas AUC0─inf was unaffected. Geometric mean percentage of total dose of selvigaltin excreted in urine over 0─96 h was 30.3% and 35.9% for the tablet under fasted and fed conditions, respectively, and 14.5% for the capsules. No treatment-emergent severe or serious adverse events or study discontinuations due to a treatment-emergent adverse event were reported.

CONCLUSION

The tablet formulation of selvigaltin displayed higher bioavailability vs. the capsule formulation, with minimal effect of food on PK. Selvigaltin was well-tolerated during all treatments. These findings warrant further clinical development of the tablet formulation of selvigaltin without specific food restrictions.

CLINICAL TRIAL REGISTRATION

NCT05747573; February 28, 2023.

High-Throughput Extracellular Matrix Proteomics of Human Lungs Enabled by Photocleavable Surfactant and diaPASEF

The extracellular matrix (ECM) is a complex assembly of proteins that provide interstitial scaffolding and elastic recoil for human lungs. The pulmonary extracellular matrix is increasingly recognized as an independent bioactive entity, by creating biochemical and mechanical signals that influence disease pathogenesis, making it an attractive therapeutic target. However, the pulmonary ECM proteome ("matrisome") remains challenging to analyze by mass spectrometry due to its inherent biophysical properties and relatively low abundance. Here, we introduce a strategy designed for rapid and efficient characterization of the human pulmonary ECM using the photocleavable surfactant Azo. We coupled this approach with trapped ion mobility MS with diaPASEF to maximize the depth of matrisome coverage. Using this strategy, we identify nearly 400 unique matrisome proteins with excellent reproducibility that are known to be important in lung biology, including key core matrisome proteins.

Emerging Roles of Galectin-3 in Pulmonary Diseases

Galectin-3 is a multifunctional protein that is involved in various physiological and pathological events. Emerging evidence suggests that galectin-3 also plays a critical role in the pathogenesis of pulmonary diseases. Galectin-3 can be produced and secreted by various cell types in the lungs, and the overexpression of galectin-3 has been found in acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary hypertension (PH), pulmonary fibrosis diseases, lung cancer, lung infection, chronic obstructive pulmonary disease (COPD), and asthma. Galectin-3 exerts diverse effects on the inflammatory response, immune cell activation, fibrosis and tissue remodeling, and tumorigenesis in these pulmonary disorders, and genetic and pharmacologic modulation of galectin-3 has therapeutic effects on the treatment of pulmonary illnesses. In this review, we summarize the structure and function of galectin-3 and the underlying mechanisms of galectin-3 in pulmonary disease pathologies; we also discuss preclinical and clinical evidence regarding the therapeutic potential of galectin-3 inhibitors in these pulmonary disorders. Additionally, targeting galectin-3 may be a very promising therapeutic approach for the treatment of pulmonary diseases.

The Possible Effects of Galectin-3 on Mechanisms of Renal and Hepatocellular Injury Induced by Intravascular Hemolysis

Intravascular hemolysis is a central feature of congenital and acquired hemolytic anemias, complement disorders, infectious diseases, and toxemias. Massive and/or chronic hemolysis is followed by the induction of inflammation, very often with severe damage of organs, which enhances the morbidity and mortality of hemolytic diseases. Galectin-3 (Gal-3) is a β-galactoside-binding lectin that modulates the functions of many immune cells, thus affecting inflammatory processes. Gal-3 is also one of the main regulators of fibrosis. The role of Gal-3 in the development of different kidney and liver diseases and the potential of therapeutic Gal-3 inhibition have been demonstrated. Therefore, the objective of this review is to discuss the possible effects of Gal-3 on the process of kidney and liver damage induced by intravascular hemolysis, as well as to shed light on the potential therapeutic targeting of Gal-3 in intravascular hemolysis.

Transcriptome Analyses of Liver Sinusoidal Endothelial Cells Reveal a Consistent List of Candidate Genes Associated with Endothelial Dysfunction and the Fibrosis Progression

Liver fibrosis is an important step in the transformation of chronic liver disease into cirrhosis and liver cancer, and structural changes and functional disorders of liver sinusoidal endothelial cells (LSECs) are early events in the occurrence of liver fibrosis. Therefore, it is necessary to identify the key regulatory genes of endothelial dysfunction in the process of liver fibrosis to provide a reference for the diagnosis and treatment of liver fibrosis. In this study, we identified 230 common differentially expressed genes (Co-DEGs) by analyzing transcriptomic data of primary LSECs from three different liver fibrosis mouse models (carbon tetrachloride; choline-deficient, l-amino acid-defined diet; and nonalcoholic steatohepatitis). Enrichment analysis revealed that the Co-DEGs were mainly involved in regulating the inflammatory response, immune response, angiogenesis, formation and degradation of the extracellular matrix, and mediating chemokine-related pathways. A Venn diagram analysis was used to identify 17 key genes related to the progression of liver cirrhosis. Regression analysis using the Lasso-Cox method identified genes related to prognosis among these key genes: SOX4, LGALS3, SERPINE2, CD52, and LPXN. In mouse models of liver fibrosis (bile duct ligation and carbon tetrachloride), all five key genes were upregulated in fibrotic livers. This study identified key regulatory genes for endothelial dysfunction in liver fibrosis, namely SOX4, LGALS3, SERPINE2, CD52, and LPXN, which will provide new targets for the development of therapeutic strategies targeting endothelial dysfunction in LSECs and liver fibrosis.

Immune mechanisms in fibrotic interstitial lung disease

Fibrotic interstitial lung diseases (fILDs) have poor survival rates and lack effective therapies. Despite evidence for immune mechanisms in lung fibrosis, immunotherapies have been unsuccessful for major types of fILD. Here, we review immunological mechanisms in lung fibrosis that have the potential to impact clinical practice. We first examine innate immunity, which is broadly involved across fILD subtypes. We illustrate how innate immunity in fILD involves a complex interplay of multiple cell subpopulations and molecular pathways. We then review the growing evidence for adaptive immunity in lung fibrosis to provoke a re-examination of its role in clinical fILD. We close with future directions to address key knowledge gaps in fILD pathobiology: (1) longitudinal studies emphasizing early-stage clinical disease, (2) immune mechanisms of acute exacerbations, and (3) next-generation immunophenotyping integrating spatial, genetic, and single-cell approaches. Advances in these areas are essential for the future of precision medicine and immunotherapy in fILD.

Network pharmacology and experimental verification to decode the action of Qing Fei Hua Xian Decotion against pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis (PF) is a common interstitial pneumonia disease, also occurred in post-COVID-19 survivors. The mechanism underlying the anti-PF effect of Qing Fei Hua Xian Decotion (QFHXD), a traditional Chinese medicine formula applied for treating PF in COVID-19 survivors, is unclear. This study aimed to uncover the mechanisms related to the anti-PF effect of QFHXD through analysis of network pharmacology and experimental verification.

METHODS

The candidate chemical compounds of QFHXD and its putative targets for treating PF were achieved from public databases, thereby we established the corresponding "herb-compound-target" network of QFHXD. The protein-protein interaction network of potential targets was also constructed to screen the core targets. Furthermore, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to predict targets, and pathways, then validated by in vivo experiments.

RESULTS

A total of 188 active compounds in QFHXD and 50 target genes were identified from databases. The key therapeutic targets of QFHXD, such as PI3K/Akt, IL-6, TNF, IL-1β, STAT3, MMP-9, and TGF-β1 were identified by KEGG and GO analysis. Anti-PF effects of QFHXD (in a dose-dependent manner) and prednisone were confirmed by HE, Masson staining, and Sirius red staining as well as in vivo Micro-CT and immunohistochemical analysis in a rat model of bleomycin-induced PF. Besides, QFXHD remarkably inhibits the activity of PI3K/Akt/NF-κB and TGF-β1/Smad2/3.

CONCLUSIONS

QFXHD significantly attenuated bleomycin-induced PF via inhibiting inflammation and epithelial-mesenchymal transition. PI3K/Akt/NF-κB and TGF-β1/Smad2/3 pathways might be the potential therapeutic effects of QFHXD for treating PF.

A Quantitative Human Red Blood Cell Agglutination Assay for Characterisation of Galectin Inhibitors

Galectins are a family of beta-galactoside-binding proteins that are characterised by their carbohydrate recognition domain (CRD) and include galectin-1 and galectin-3. These galectins have been implicated in numerous diseases due to their pleiotropic nature, including cancer and fibrosis, with therapeutic inhibitors being clinically developed to block the CRD. One of the early methods developed to characterise these galectins was the hemagglutination of red blood cells. Although it is insightful, this approach has been hampered by a lack of sensitivity and accurate quantification of the agglutination observed. In this study, we aimed to validate a more precise and quantitative method to enable the further investigation of differences between galectins in respect to agglutination induction in different blood groups, as well as the characterisation of small molecule inhibitors. Quantification of hemagglutination was shown to be optimal using U-bottom plates imaged and analysed with FIJI ImageJ rather than flat-bottom plates read for absorbance on an optical density plate reader. Galectin-3-induced red blood cell agglutination efficacy increased significantly from blood group O to A to B. However, for both the galectin-1 monomer and concatemer, a more comparable effect was observed between blood group B and O, but with more potent effects than in blood group A. Inhibition assays for both galectin-3 and galectin-1 induced-hemagglutination were able to demonstrate clear concentration responses and expected selectivity profiles for a set of small-molecule glycomimetics, confirming the historical profiles obtained in biochemical binding and functional cellular assays.

Galectin-3 inhibition alleviated LPS-induced periodontal inflammation in gingival fibroblasts and experimental periodontitis mice

OBJECTIVES

Clinical studies have confirmed that galectin-3 (Gal-3) levels are significantly elevated in periodontitis patients. The present study aimed to explore the effects of Gal-3 inhibition on periodontal inflammation in vitro and in vivo.

METHODS

Human gingival fibroblasts (HGFs) with or without Gal-3 knockdown were stimulated by lipopolysaccharide (LPS), and a ligation-induced mouse periodontitis model treated with a Gal-3 inhibitor was established. Hematoxylin-eosin (H&E) and immunohistochemistry (IHC) staining were used to evaluate Gal-3 levels in gingival tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to detect Gal-3, interleukin (IL)-6, IL-8, and C-C motif ligand 2 (CCL2) expression. Immunofluorescence and western blotting were used to detect NF-κB and ERK signaling pathway activation. Micro-computed tomography was used to analyse the degree of bone loss.

RESULTS

Gal-3 was significantly up-regulated in inflamed gingival tissues and LPS-induced HGFs. Gal-3 knockdown markedly decreased LPS-induced IL-6, IL-8, and CCL2 expression and blocked NF-κB and ERK signaling pathway activation in HGFs. In the mouse periodontitis model, Gal-3 inhibition significantly alleviated IL-1β and IL-6 infiltration in gingival tissue and mitigated periodontal bone loss.

CONCLUSIONS

Gal-3 inhibition notably alleviated periodontal inflammation partly through blocking NF-κB and ERK signaling pathway activation.

Oligonucleotide therapies for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) represents a severe disease subtype of nonalcoholic fatty liver disease (NAFLD) that is thought to be highly associated with systemic metabolic abnormalities. It is characterized by a series of substantial liver damage, including hepatocellular steatosis, inflammation, and fibrosis. The end stage of NASH, in some cases, may result in cirrhosis and hepatocellular carcinoma (HCC). Nowadays a large number of investigations are actively under way to test various therapeutic strategies, including emerging oligonucleotide drugs (e.g., antisense oligonucleotide, small interfering RNA, microRNA, mimic/inhibitor RNA, and small activating RNA) that have shown high potential in treating this fatal liver disease. This article systematically reviews the pathogenesis of NASH/NAFLD, the promising druggable targets proven by current studies in chemical compounds or biological drug development, and the feasibility and limitations of oligonucleotide-based therapeutic approaches under clinical or pre-clinical studies.

Biomarkers in idiopathic pulmonary fibrosis: Current insight and future direction

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease with a dismal prognosis. Early diagnosis, accurate prognosis, and personalized therapeutic interventions are essential for improving patient outcomes. Biomarkers, as measurable indicators of biological processes or disease states, hold significant promise in IPF management. In recent years, there has been a growing interest in identifying and validating biomarkers for IPF, encompassing various molecular, imaging, and clinical approaches. This review provides an in-depth examination of the current landscape of IPF biomarker research, highlighting their potential applications in disease diagnosis, prognosis, and treatment response. Additionally, the challenges and future perspectives of biomarker integration into clinical practice for precision medicine in IPF are discussed.

Defining the mechanism of galectin-3-mediated TGF-β1 activation and its role in lung fibrosis

Integrin-mediated activation of the profibrotic mediator transforming growth factor-β1 (TGF-β1), plays a critical role in idiopathic pulmonary fibrosis (IPF) pathogenesis. Galectin-3 is believed to contribute to the pathological wound healing seen in IPF, although its mechanism of action is not precisely defined. We hypothesized that galectin-3 potentiates TGF-β1 activation and/or signaling in the lung to promote fibrogenesis. We show that galectin-3 induces TGF-β1 activation in human lung fibroblasts (HLFs) and specifically that extracellular galectin-3 promotes oleoyl-L-α-lysophosphatidic acid sodium salt-induced integrin-mediated TGF-β1 activation. Surface plasmon resonance analysis confirmed that galectin-3 binds to αv integrins, αvβ1, αvβ5, and αvβ6, and to the TGFβRII subunit in a glycosylation-dependent manner. This binding is heterogeneous and not a 1:1 binding stoichiometry. Binding interactions were blocked by small molecule inhibitors of galectin-3, which target the carbohydrate recognition domain. Galectin-3 binding to β1 integrin was validated in vitro by coimmunoprecipitation in HLFs. Proximity ligation assays indicated that galectin-3 and β1 integrin colocalize closely (≤40 nm) on the cell surface and that colocalization is increased by TGF-β1 treatment and blocked by galectin-3 inhibitors. In the absence of TGF-β1 stimulation, colocalization was detectable only in HLFs from IPF patients, suggesting the proteins are inherently more closely associated in the disease state. Galectin-3 inhibitor treatment of precision cut lung slices from IPF patients' reduced Col1a1, TIMP1, and hyaluronan secretion to a similar degree as TGF-β type I receptor inhibitor. These data suggest that galectin-3 promotes TGF-β1 signaling and may induce fibrogenesis by interacting directly with components of the TGF-β1 signaling cascade.

Galectin-3 impairs calcium transients and β-cell function

In diabetes, macrophages and inflammation are increased in the islets, along with β-cell dysfunction. Here, we demonstrate that galectin-3 (Gal3), mainly produced and secreted by macrophages, is elevated in islets from both high-fat diet (HFD)-fed and diabetic db/db mice. Gal3 acutely reduces glucose-stimulated insulin secretion (GSIS) in β-cell lines and primary islets in mice and humans. Importantly, Gal3 binds to calcium voltage-gated channel auxiliary subunit gamma 1 (CACNG1) and inhibits calcium influx via the cytomembrane and subsequent GSIS. β-Cell CACNG1 deficiency phenocopies Gal3 treatment. Inhibition of Gal3 through either genetic or pharmacologic loss of function improves GSIS and glucose homeostasis in both HFD-fed and db/db mice. All animal findings are applicable to male mice. Here we show a role of Gal3 in pancreatic β-cell dysfunction, and Gal3 could be a therapeutic target for the treatment of type 2 diabetes.

Can Galectin-3 be a reliable predictive biomarker for post-COVID syndrome development?

BACKGROUND AND OBJECTIVES

Reliable biomarkers able to predict post-COVID syndrome development are still lacking. The aim of the study was to evaluate the relationship between Galectin-3 blood concentrations and the development of post-COVID syndrome.

METHODS

We performed a single-center, prospective, observational study, enrolling 437 consecutive patients attending our outpatient clinic for the post-COVID assessment. For each patient, we recorded the main clinical, functional and radiological findings. We also dosed several blood biomarkers which have been related to COVID-19 disease, including Galectin-3. We performed Receiver Operating Characteristic (ROC) and multivariate regression analysis to evaluate the predictive performance of Galectin-3 for post-COVID syndrome development.

RESULTS

Among the blood biomarkers tested, Galectin-3 resulted the only one correlated with the outcome, although the insufficient performance of the Cox regression model from a statistical standpoint. Correlation coefficients and ROC curves analysis revealed the close relationship between Galectin-3 levels and the time passed from the acute phase of COVID-19 disease, suggesting a possible predictive role for this biomarker when dosed from 60 to 120 days after the infection.

CONCLUSIONS

Galectin-3 could play an important role as predictive biomarker for COVID-19 sequelae, but its evaluation must be carefully planned along the follow up to avoid misinterpretations.

Galectins in epithelial-mesenchymal transition: roles and mechanisms contributing to tissue repair, fibrosis and cancer metastasis

Galectins are soluble glycan-binding proteins that interact with a wide range of glycoproteins and glycolipids and modulate a broad spectrum of physiological and pathological processes. The expression and subcellular localization of different galectins vary among tissues and cell types and change during processes of tissue repair, fibrosis and cancer where epithelial cells loss differentiation while acquiring migratory mesenchymal phenotypes. The epithelial-mesenchymal transition (EMT) that occurs in the context of these processes can include modifications of glycosylation patterns of glycolipids and glycoproteins affecting their interactions with galectins. Moreover, overexpression of certain galectins has been involved in the development and different outcomes of EMT. This review focuses on the roles and mechanisms of Galectin-1 (Gal-1), Gal-3, Gal-4, Gal-7 and Gal-8, which have been involved in physiologic and pathogenic EMT contexts.

Exploring therapeutic targets for molecular therapy of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis is a chronic and progressive interstitial lung disease with a poor prognosis. Idiopathic pulmonary fibrosis is characterized by repeated alveolar epithelial damage leading to abnormal repair. The intercellular microenvironment is disturbed, leading to continuous activation of fibroblasts and myofibroblasts, deposition of extracellular matrix, and ultimately fibrosis. Moreover, pulmonary fibrosis was also found as a COVID-19 complication. Currently, two drugs, pirfenidone and nintedanib, are approved for clinical therapy worldwide. However, they can merely slow the disease's progression rather than rescue it. These two drugs have other limitations, such as lack of efficacy, adverse effects, and poor pharmacokinetics. Consequently, a growing number of molecular therapies have been actively developed. Treatment options for IPF are becoming increasingly available. This article reviews the research platform, including cell and animal models involved in molecular therapy studies of idiopathic pulmonary fibrosis as well as the promising therapeutic targets and their development progress during clinical trials. The former includes patient case/control studies, cell models, and animal models. The latter includes transforming growth factor-beta, vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, lysophosphatidic acid, interleukin-13, Rho-associated coiled-coil forming protein kinase family, and Janus kinases/signal transducers and activators of transcription pathway. We mainly focused on the therapeutic targets that have not only entered clinical trials but were publicly published with their clinical outcomes. Moreover, this work provides an outlook on some promising targets for further validation of their possibilities to cure the disease.

Insights into Disease Progression of Translational Preclinical Rat Model of Interstitial Pulmonary Fibrosis through Endpoint Analysis

Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease characterized by the relentless deposition of extracellular matrix (ECM), causing lung distortions and dysfunction. Animal models of human IPF can provide great insight into the mechanistic pathways underlying disease progression and a means for evaluating novel therapeutic approaches. In this study, we describe the effect of bleomycin concentration on disease progression in the classical rat bleomycin model. In a dose-response study (1.5, 2, 2.5 U/kg i.t), we characterized lung fibrosis at day 14 after bleomycin challenge using endpoints including clinical signs, inflammatory cell infiltration, collagen content, and bronchoalveolar lavage fluid-soluble profibrotic mediators. Furthermore, we investigated fibrotic disease progression after 2 U/kg i.t. bleomycin administration at days 3, 7, and 14 by quantifying the expression of clinically relevant signaling molecules and pathways, epithelial mesenchymal transition (EMT) biomarkers, ECM components, and histopathology of the lung. A single bleomycin challenge resulted in a progressive fibrotic response in rat lung tissue over 14 days based on lung collagen content, histopathological changes, and modified Ashcroft score. The early fibrogenesis phase (days 3 to 7) is associated with an increase in profibrotic mediators including TGFβ1, IL6, TNFα, IL1β, CINC1, WISP1, VEGF, and TIMP1. In the mid and late fibrotic stages, the TGFβ/Smad and PDGF/AKT signaling pathways are involved, and clinically relevant proteins targeting galectin-3, LPA1, transglutaminase-2, and lysyl oxidase 2 are upregulated on days 7 and 14. Between days 7 and 14, the expressions of vimentin and α-SMA proteins increase, which is a sign of EMT activation. We confirmed ECM formation by increased expressions of procollagen-1Aα, procollagen-3Aα, fibronectin, and CTGF in the lung on days 7 and 14. Our data provide insights on a complex network of several soluble mediators, clinically relevant signaling pathways, and target proteins that contribute to drive the progressive fibrotic phenotype from the early to late phase (active) in the rat bleomycin model. The framework of endpoints of our study highlights the translational value for pharmacological interventions and mechanistic studies using this model.

Anti-Angiogenic and Anti-Scarring Dual Effect of Galectin-3 Inhibition in Mouse Models of Corneal Wound Healing

Corneal scarring is the third leading cause of global blindness. Neovascularization of ocular tissues is a major predisposing factor in scar development. Although corneal transplantation is effective in restoring vision, some patients are at high risk for graft rejection due to the presence of blood vessels in the injured cornea. Current treatment options for controlling corneal scarring are limited, and outcomes are typically poor. In this study, topical application of a small-molecule inhibitor of galectin-3, GB1265, in mouse models of corneal wound healing, led to the reduction of the following in injured corneas: i) corneal angiogenesis; ii) corneal fibrosis; iii) infiltration of immune cells; and iv) expression of the proinflammatory cytokine IL-1β. Four independent techniques (RNA sequencing, NanoString, real-time quantitative RT-PCR, and Western blot analysis) determined that decreased corneal opacity in the galectin-3 inhibitor-treated corneas was associated with decreases in the numbers of genes and signaling pathways known to promote fibrosis. These findings allowed for a high level of confidence in the conclusion that galectin-3 inhibition by the small-molecule inhibitor GB1265 has dual anti-angiogenic and anti-scarring effects. Targeting galectin-3 by GB1265 is, thus, attractive for the development of innovative therapies for a myriad of ocular and nonocular diseases characterized by pathologic angiogenesis and fibrosis.

Identification of benzothiazole derived monosaccharides as potent, selective, and orally bioavailable inhibitors of human and mouse galectin-3; a rare example of using a S···O binding interaction for drug design

As a result of our continued efforts to pursue Gal-3 inhibitors that could be used to fully evaluate the potential of Gal-3 as a therapeutic target, two novel series of benzothiazole derived monosaccharides as potent (against both human and mouse Gal-3) and orally bioavailable Gal-3 inhibitors, represented by 4 and 5, respectively, were identified. These discoveries were made based on proposals that the benzothiazole sulfur atom could interact with the carbonyl oxygen of G182/G196 in h/mGal-3, and that the anomeric triazole moiety could be modified into an N-methyl carboxamide functionality. The interaction between the benzothiazole sulfur and the carbonyl oxygen of G196 in mGal-3 was confirmed by an X-ray co-crystal structure of early lead 9, providing a rare example of using a S···O binding interaction for drug design. It was found that for both the series, methylation of 3-OH in the monosaccharides caused no loss in h & mGal-3 potencies but significantly improved permeability of the molecules.

Galectin-3 is involved in inflammation and fibrosis in arteriogenic erectile dysfunction via the TLR4/MyD88/NF-κB pathway

Galectin-3 (Gal-3) is a multifunctional protein that has been linked to fibrosis and inflammation in the cardiovascular system. In this study, we examined the impact of Gal-3 on inflammation and fibrosis in patients with arteriogenic erectile dysfunction (A-ED) and the underlying mechanisms involved. To induce arterial injury, we utilized cuffs on the periaqueductal common iliac arteries of Sprague‒Dawley (SD) rats and administered a high-fat diet to co-induce local atherosclerosis. Our results showed that we successfully developed a novel A-ED model that was validated based on histological evidence. In vivo, the vascular lumen of rats subjected to a high-fat diet and cuff placement exhibited significant narrowing, accompanied by the upregulation of Gal-3, Toll-like receptor 4 (TLR4), and myeloid differentiation primary response protein 88 (MyD88) expression in the penile cavernosa. This led to the activation of nuclear factor kappa B 65 (NF-κB-p65), resulting in reduced intracavernosal pressure, endothelial nitric oxide synthase expression, and smooth muscle content, promoting inflammation and fibrosis. However, treatment with Gal-3 inhibitor-modified citrus pectin (MCP) significantly normalized those effects. In vitro, knocking down Gal-3 led to a significant reduction in TLR4, MyD88, and NF-κB-p65 expression in corpus cavernosum smooth muscle cells (CCSMCs), decreasing inflammation levels. In conclusion, inhibiting Gal-3 may improve A-ED by reducing inflammation, endothelial injury, and fibrosis in the penile corpus cavernosum through the TLR4/MyD88/NF-κB pathway. These findings highlight the potential therapeutic target of Gal-3 in A-ED.

Cigarette smoke-induced galectin-3 as a diagnostic biomarker and therapeutic target in lung tissue remodeling

Galectin-3 (Gal-3), a multifunctional carbohydrate-binding lectin, has emerged as a key player in various biological processes including inflammation, cancer, cardiovascular diseases and fibrotic disorders, however it remains unclear if Gal-3 is a bystander or drives lung tissue remodeling (LTR). Persistent exposure to cigarette smoke (CS) is the leading cause of oxidative and inflammatory damage to the lung tissues. CS-induced pathological increase in Gal-3 expression has been implicated in the pathogenesis of various respiratory conditions, such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and lung cancer. We and others have reported that CS induces Gal-3 synthesis and secretion, which modulates the pathological signaling pathways in lung epithelial cells implicating Gal-3 as a novel diagnostic marker and a factor driving LTR in CS-exposed lungs. Therefore, pharmacological interventions targeting Gal-3 and its upstream and downstream signaling pathways can help combat CS-induced LTR. Excitingly, preclinical models have demonstrated the efficacy of interventions such as Gal-3 expression inhibition, Gal-3 receptor blockade, and signaling pathways modulation open up promising avenues for future therapeutic interventions. Furthermore, targeting extracellular vesicles-mediated Gal-3 release and the potential of microRNA-based therapy are emerging as novel therapeutic approaches in CS-induced LTR and have been discussed in this article.

CCL18, CHI3L1, ANG2, IL-6 systemic levels are associated with the extent of lung damage and radiomic features in SARS-CoV-2 infection

OBJECTIVE AND DESIGN

We aimed to identify cytokines whose concentrations are related to lung damage, radiomic features, and clinical outcomes in COVID-19 patients.

MATERIAL OR SUBJECTS

Two hundred twenty-six patients with SARS-CoV-2 infection and chest computed tomography (CT) images were enrolled.

METHODS

CCL18, CHI3L1/YKL-40, GAL3, ANG2, IP-10, IL-10, TNFα, IL-6, soluble gp130, soluble IL-6R were quantified in plasma samples using Luminex assays. The Mann-Whitney U test, the Kruskal-Wallis test, correlation and regression analyses were performed. Mediation analyses were used to investigate the possible causal relationships between cytokines, lung damage, and outcomes. AVIEW lung cancer screening software, pyradiomics, and XGBoost classifier were used for radiomic feature analyses.

RESULTS

CCL18, CHI3L1, and ANG2 systemic levels mainly reflected the extent of lung injury. Increased levels of every cytokine, but particularly of IL-6, were associated with the three outcomes: hospitalization, mechanical ventilation, and death. Soluble IL-6R showed a slight protective effect on death. The effect of age on COVID-19 outcomes was partially mediated by cytokine levels, while CT scores considerably mediated the effect of cytokine levels on outcomes. Radiomic-feature-based models confirmed the association between lung imaging characteristics and CCL18 and CHI3L1.

CONCLUSION

Data suggest a causal link between cytokines (risk factor), lung damage (mediator), and COVID-19 outcomes.

Galectin-3 Mediates Endotoxin Internalization and Caspase-4/11 Activation in Tubular Epithelials and Macrophages During Sepsis and Sepsis-Associated Acute Kidney Injury

Besides being recognized by membrane receptor TLR4, lipopolysaccharide (LPS) can also be internalized into the cytosol and activate Caspase-4/11 pyroptotic pathways to further amplify inflammation in sepsis. The objective of this study was to investigate whether Galectin-3 (Gal3) could promote the uptake of LPS by governing RAGE or administering endocytosis, consequently activating Caspase 4/11 and mediating pyroptosis in sepsis-associated acute kidney injury (SA-AKI). By pinpointing Gal3, LPS, and EEA1 (endosome-marker) or LAMP1 (lysosome-marker) respectively, immunofluorescence discovered that Gal3 and LPS were mainly aggregated in early endosomes initially and translocated into lysosomes afterwards. In cells and animal models, Gal3 and the Caspase-4/11 pathways were simultaneously activated, and the overexpression of Gal3 could exacerbate pyroptosis, whereas inhibition of Gal3 or the knockdown of its expression could ameliorate pyroptosis, reduce the pathological changes of SA-AKI and improve the survival of the animals with SA-AKI. Silencing RAGE reduced pyroptosis in primary tubular epithelial cells (PTCs) activated by Gal3 and LPS but not in cells activated by Gal3 and outer membrane vesicles (with LPS inside), whereas pyroptosis in both was reduced by blockade of Gal3, indicating Gal3 promoted pyroptosis through both RAGE-dependent and RAGE-independent pathways. Our investigation further revealed a positive correlation between serum Gal3 and pyroptotic biomarkers IL-1 beta and IL-18 in patients with sepsis, and that serum Gal3 was an independent risk factor for mortality. Through our collective exploration, we unraveled the significant role of Gal3 in the internalization of LPS and the provocation of more intense pyroptosis, thus making it a vital pathogenic factor in SA-AKI and a possible therapeutic target. Gal3 enabled the internalization of endotoxin into endosomes and lysosomes via both RAGE-dependent (A) and RAGE-independent (B) pathways, leading to pyroptosis. The suppression of Gal3 curbed Caspase4/11 noncanonical inflammasomes and diminished sepsis and SA-AKI.

Therapeutic potential of melatonin in targeting molecular pathways of organ fibrosis

Fibrosis, the excessive deposition of fibrous connective tissue in an organ in response to injury, is a pathological condition affecting many individuals worldwide. Fibrosis causes the failure of tissue function and is largely irreversible as the disease progresses. Pharmacologic treatment options for organ fibrosis are limited, but studies suggest that antioxidants, particularly melatonin, can aid in preventing and controlling fibrotic damage to the organs. Melatonin, an indole nocturnally released from the pineal gland, is commonly used to regulate circadian and seasonal biological rhythms and is indicated for treating sleep disorders. While it is often effective in treating sleep disorders, melatonin's anti-inflammatory and antioxidant properties also make it a promising molecule for treating other disorders such as organ fibrosis. Melatonin ameliorates the necrotic and apoptotic changes that lead to fibrosis in various organs including the heart, liver, lung, and kidney. Moreover, melatonin reduces the infiltration of inflammatory cells during fibrosis development. This article outlines the protective effects of melatonin against fibrosis, including its safety and potential therapeutic effects. The goal of this article is to provide a summary of data accumulated to date and to encourage further experimentation with melatonin and increase its use as an anti-fibrotic agent in clinical settings.

CircMMP2(6,7) Cooperates with β-Catenin and PRMT5 to Disrupt Bone Homeostasis and Promote Breast Cancer Bone Metastasis

The bone is the most common site of distant metastasis of breast cancer, which leads to serious skeletal complications and mortality. Understanding the mechanisms underlying breast cancer bone metastasis would provide potential strategies for the prevention and treatment of breast cancer bone metastasis. In this study, we identified a circular RNA that we named circMMP2(6,7) that was significantly upregulated in bone metastatic breast cancer tissues and correlated with breast cancer-bone metastasis. Upregulation of circMMP2(6,7) dramatically enhanced the metastatic capability of breast cancer cells to the bone via inducing bone metastatic niche formation by disrupting bone homeostasis. Mechanistically, circMMP2(6,7) specifically bound to the promoters of bone-remodeling factors calcium-binding protein S100A4 and carbohydrate-binding protein LGALS3 and formed a complex with β-catenin and arginine methyltransferase PRMT5, eliciting histone H3R2me1/H3R2me2s-induced transcriptional activation. Treatment with GSK591, a selective PRMT5 inhibitor, effectively inhibited circMMP2(6,7)/β-catenin/PRMT5 complex-induced breast cancer bone metastasis. These findings reveal a role for circMMP2(6,7) in bone homeostasis disruption and shed light on the mechanisms driving breast cancer bone metastasis.

SIGNIFICANCE

Upregulation of bone-remodeling factors S100A4 and LGALS3 mediated by a circMMP2(6,7)/β-catenin/PRMT5 complex generates a niche that supports breast cancer bone metastasis, identifying PRMT5 as a promising target for treating metastasis.

Inhibition of Pro-Fibrotic Molecules Expression in Idiopathic Pulmonary Fibrosis-Derived Lung Fibroblasts by Lactose-Modified Hyaluronic Acid Compounds

Idiopathic pulmonary fibrosis (IPF) is a chronic inflammatory and fibrotic pathological condition with undefined effective therapies and a poor prognosis, partly due to the lack of specific and effective therapies. Galectin 3 (Gal-3), a pro-fibrotic ß-galactoside binding lectin, was upregulated in the early stages of the pathology, suggesting that it may be considered a marker of active fibrosis. In the present in vitro study, we use Hylach®, a lactose-modified hyaluronic acid able to bind Gal-3, to prevent the activation of lung myofibroblast and the consequent excessive ECM protein cell expression. Primary human pulmonary fibroblasts obtained from normal and IPF subjects activated with TGF-β were used, and changes in cell viability, fibrotic components, and pro-inflammatory mediator expression at both gene and protein levels were analyzed. Hylach compounds with a lactosylation degree of about 10% and 30% (Hylach1 and Hylach 2), administrated to TGF-β-stimulated lung fibroblast cultures, significantly downregulated α-smooth muscle actin (α-SMA) gene expression and decreased collagen type I, collagen type III, elastin, fibronectin gene and protein expression to near baseline values. This anti-fibrotic activity is accompanied by a strong anti-inflammatory effect and by a downregulation of the gene expression of Smad2 for both Hylachs in comparison to the native HA. In conclusion, the Gal-3 binding molecules Hylachs attenuated inflammation and TGF-β-induced over-expression of α-SMA and ECM protein expression by primary human lung fibroblasts, providing a new direction for the treatment of pulmonary fibrotic diseases.

Mesenchymal ovarian cancer cells promote CD8+ T cell exhaustion through the LGALS3-LAG3 axis

Cancer cells often metastasize by undergoing an epithelial-mesenchymal transition (EMT). Although abundance of CD8+ T-cells in the tumor microenvironment correlates with improved survival, mesenchymal cancer cells acquire greater resistance to antitumor immunity in some cancers. We hypothesized the EMT modulates the immune response to ovarian cancer. Here we show that cancer cells from infiltrated/inflamed tumors possess more mesenchymal cells, than excluded and desert tumors. We also noted high expression of LGALS3 is associated with EMT in vivo, a finding validated with in vitro EMT models. Dissecting the cellular communications among populations in the tumor revealed that mesenchymal cancer cells in infiltrated tumors communicate through LGALS3 to LAG3 receptor expressed by CD8+ T cells. We found CD8+ T cells express high levels of LAG3, a marker of T cell exhaustion. The results indicate that EMT in ovarian cancer cells promotes interactions between cancer cells and T cells through the LGALS3 - LAG3 axis, which could increase T cell exhaustion in infiltrated tumors, dampening antitumor immunity.

M-type pyruvate kinase 2 (PKM2) tetramerization alleviates the progression of right ventricle failure by regulating oxidative stress and mitochondrial dynamics

BACKGROUND

Right ventricle failure (RVF) is a progressive heart disease that has yet to be fully understood at the molecular level. Elevated M-type pyruvate kinase 2 (PKM2) tetramerization alleviates heart failure, but detailed molecular mechanisms remain unclear.

OBJECTIVE

We observed changes in PKM2 tetramerization levels during the progression of right heart failure and in vitro cardiomyocyte hypertrophy and explored the causal relationship between altered PKM2 tetramerization and the imbalance of redox homeostasis in cardiomyocytes, as well as its underlying mechanisms. Ultimately, our goal was to propose rational intervention strategies for the treatment of RVF.

METHOD

We established RVF in Sprague Dawley (SD) rats by intraperitoneal injection of monocrotaline (MCT). The pulmonary artery pressure and right heart function of rats were assessed using transthoracic echocardiography combined with right heart catheterization. TEPP-46 was used both in vivo and in vitro to promote PKM2 tetramerization.

RESULTS

We observed that oxidative stress and mitochondrial disorganization were associated with increased apoptosis in the right ventricular tissue of RVF rats. Quantitative proteomics revealed that PKM2 was upregulated during RVF and negatively correlated with the cardiac function. Facilitating PKM2 tetramerization promoted mitochondrial network formation and alleviated oxidative stress and apoptosis during cardiomyocyte hypertrophy. Moreover, enhancing PKM2 tetramer formation improved cardiac mitochondrial morphology, mitigated oxidative stress and alleviated heart failure.

CONCLUSION

Disruption of PKM2 tetramerization contributed to RVF by inducing mitochondrial fragmentation, accumulating ROS, and finally promoted the progression of cardiomyocyte apoptosis. Facilitating PKM2 tetramerization holds potential as a promising therapeutic approach for RVF.

Telocytes protect against lung tissue fibrosis through hexokinase 2-dependent pathway by secreting hepatocyte growth factor

Pulmonary fibrosis (PF) is one of the common manifestations of end-stage lung disease. Chronic lung failure after lung transplantation is mainly caused by bronchiolitis obliterans syndrome (BOS) and is mainly characterized by lung tissue fibrosis. Pulmonary epithelial-mesenchymal transformation (EMT) is crucial for pulmonary fibrosis. Telocytes (TCs), a new type of mesenchymal cells, play a protective role in various acute injuries. For exploring the anti-pulmonary fibrosis effect of TCs in the BOS model in vitro and the related mechanism, rat tracheal epithelial (RTE) cells were treated with transforming growth factor-β (TGF-β) to simulate lung tissue fibrosis in vitro. The RTE cells were then co-cultured with TCs primarily extracted from rat lung tissue. Western blot, Seahorse XF Analysers and enzyme-linked immunosorbent assay were used to detect the level of EMT and aerobic respiration of RTE cells. Furthermore, anti-hepatocyte growth factor (anti-HGF) antibody was exogenously added to the cultured cells to explore further mechanisms. Moreover, hexokinase 2 (HK2) in RTE cells was knocked down to assess whether it influences the blocking effect of the anti-HGF antibody. TGF-β could induce lung tissue fibrosis in RTE cells in vitro. Nevertheless, TCs co-culture decreased the level of EMT, glucose metabolic indicators (lactate and ATP) and oxygen levels. Furthermore, TCs released hepatocyte growth factor (HGF). Therefore, the exogenous addition of anti-HGF antibody in the co-culture system blocked the anti-lung tissue fibrosis effect. However, HK2 knockdown attenuated the blocking effect of the anti-HGF antibody. In conclusion, TCs can protect against lung tissue fibrosis by releasing HGF, a process dependent on HK2.

TGF-β, EMT, and resistance to anti-cancer treatment

Transforming growth factor-β (TGF-β) signaling regulates cell-specific programs involved in embryonic development, wound-healing, and immune homeostasis. Yet, during tumor progression, these TGF-β-mediated programs are altered, leading to epithelial cell plasticity and a reprogramming of epithelial cells into mesenchymal lineages through epithelial-to-mesenchymal transition (EMT), a critical developmental program in morphogenesis and organogenesis. These changes, in turn, lead to enhanced carcinoma cell invasion, metastasis, immune cell differentiation, immune evasion, and chemotherapy resistance. Here, we discuss EMT as one of the critical programs associated with carcinoma cell plasticity and the influence exerted by TGF-β on carcinoma status and function. We further explore the composition of carcinoma and other cell populations within the tumor microenvironment, and consider the relevant outcomes related to the programs associated with cancer treatment resistance.

An update on emerging drugs for the treatment of idiopathic pulmonary fibrosis: a look towards 2023 and beyond

INTRODUCTION

Currently approved drug treatments for idiopathic pulmonary fibrosis (IPF), pirfenidone and nintedanib, have been shown to slow lung function decline and improve clinical outcomes. Since significant advances in the understanding of pathogenetic mechanisms in IPF, novel potential agents are being tested to identify new targeted and better tolerated therapeutic strategies.

AREAS COVERED

This review describes the evidence from IPF phase II and III clinical trials that have been completed or are ongoing in recent years. The literature search was performed using Medline and Clinicaltrials.org databases. Particular attention is paid to the new inhibitor of phosphodiesterase 4B (BI 1015550), being studied in a more advanced research phase. Some emerging critical issues of the pharmacological research are highlighted considering the recent outstanding failures of several phase III trials.

EXPERT OPINION

An exponential number of randomized clinical trials are underway testing promising new molecules to increase treatment choices for patients with IPF and improve patients' quality of life. The next goals should aim at a deeper understanding of the pathogenic pathways of the disease with the challenging goal of being able not only to stabilize but also to reverse the ongoing fibrotic process in patients with IPF.

Disclosing the molecular profile of the human amniotic mesenchymal stromal cell secretome by filter-aided sample preparation proteomic characterization

BACKGROUND

The secretome of mesenchymal stromal cells isolated from the amniotic membrane (hAMSCs) has been extensively studied for its in vitro immunomodulatory activity as well as for the treatment of several preclinical models of immune-related disorders. The bioactive molecules within the hAMSCs secretome are capable of modulating the immune response and thus contribute to stimulating regenerative processes. At present, only a few studies have attempted to define the composition of the secretome, and several approaches, including multi-omics, are underway in an attempt to precisely define its composition and possibly identify key factors responsible for the therapeutic effect.

METHODS

In this study, we characterized the protein composition of the hAMSCs secretome by a filter-aided sample preparation (FASP) digestion and liquid chromatography-high resolution mass spectrometry (LC-MS) approach. Data were processed for gene ontology classification and functional protein interaction analysis by bioinformatics tools.

RESULTS

Proteomic analysis of the hAMSCs secretome resulted in the identification of 1521 total proteins, including 662 unique elements. A number of 157 elements, corresponding to 23.7%, were found as repeatedly characterizing the hAMSCs secretome, and those that resulted as significantly over-represented were involved in immunomodulation, hemostasis, development and remodeling of the extracellular matrix molecular pathways.

CONCLUSIONS

Overall, our characterization enriches the landscape of hAMSCs with new information that could enable a better understanding of the mechanisms of action underlying the therapeutic efficacy of the hAMSCs secretome while also providing a basis for its therapeutic translation.

Inhibition of galectin-3 post-infarction impedes progressive fibrosis by regulating inflammatory profibrotic cascades

AIMS

Acute myocardial infarction (MI) causes inflammation, collagen deposition, and reparative fibrosis in response to myocyte death and, subsequently, a pathological myocardial remodelling process characterized by excessive interstitial fibrosis, driving heart failure (HF). Nonetheless, how or when to limit excessive fibrosis for therapeutic purposes remains uncertain. Galectin-3, a major mediator of organ fibrosis, promotes cardiac fibrosis and remodelling. We performed a preclinical assessment of a protein inhibitor of galectin-3 (its C-terminal domain, Gal-3C) to limit excessive fibrosis resulting from MI and prevent ventricular enlargement and HF.

METHODS AND RESULTS

Gal-3C was produced by enzymatic cleavage of full-length galectin-3 or by direct expression of the truncated form in Escherichia coli. Gal-3C was intravenously administered for 7 days in acute MI models of young and aged rats, starting either pre-MI or 4 days post-MI. Echocardiography, haemodynamics, histology, and molecular and cellular analyses were performed to assess post-MI cardiac functionality and pathological fibrotic progression. Gal-3C profoundly benefitted left ventricular ejection fraction, end-systolic and end-diastolic volumes, haemodynamic parameters, infarct scar size, and interstitial fibrosis, with better therapeutic efficacy than losartan and spironolactone monotherapies over the 56-day study. Gal-3C therapy in post-MI aged rats substantially improved pump function and attenuated ventricular dilation, preventing progressive HF. Gal-3C in vitro treatment of M2-polarized macrophage-like cells reduced their M2-phenotypic expression of arginase-1 and interleukin-10. Gal-3C inhibited M2 polarization of cardiac macrophages during reparative response post-MI. Gal-3C impeded progressive fibrosis post-MI by down-regulating galectin-3-mediated profibrotic signalling cascades including a reduction in endogenous arginase-1 and inducible nitric oxide synthase (iNOS).

CONCLUSION

Gal-3C treatment improved long-term cardiac function post-MI by reduction in the wound-healing response, and inhibition of inflammatory fibrogenic signalling to avert an augmentation of fibrosis in the periinfarct region. Thus, Gal-3C treatment prevented the infarcted heart from extensive fibrosis that accelerates the development of HF, providing a potential targeted therapy.

Ligand Sulfur Oxidation State Progressively Alters Galectin-3-Ligand Complex Conformations To Induce Affinity-Influencing Hydrogen Bonds

Galectins play biological roles in immune regulation and tumor progression. Ligands with high affinity for the shallow, hydrophilic galectin-3 ligand binding site rely primarily on a galactose core with appended aryltriazole moieties, making hydrophobic interactions and π-stacking. We designed and synthesized phenyl sulfone, sulfoxide, and sulfide-triazolyl thiogalactoside derivatives to create affinity-enhancing hydrogen bonds, hydrophobic and π-interactions. Crystal structures and thermodynamic analyses revealed that the sulfoxide and sulfone ligands form hydrogen bonds while retaining π-interactions, resulting in improved affinities and unique binding poses. The sulfoxide, bearing one hydrogen bond acceptor, leads to an affinity decrease compared to the sulfide, whereas the corresponding sulfone forms three hydrogen bonds, two directly with Asn and Arg side chains and one water-mediated to an Asp side chain, respectively, which alters the complex structure and increases affinity. These findings highlight that the sulfur oxidation state influences both the interaction thermodynamics and structure.

Idiopathic pulmonary fibrosis: Addressing the current and future therapeutic advances along with the role of Sotatercept in the management of pulmonary hypertension

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive and debilitating lung disease characterized by irreversible scarring of the lungs. The cause of IPF is unknown, but it is thought to involve a combination of genetic and environmental factors. There is no cure for IPF, and treatment is focused on slowing disease progression and relieving symptoms.

AIMS

We aimed in this review to investigate and provide the latest insights into IPF management modalities, including the potential of Saracatinibas a substitute for current IPF drugs. We also investigated the therapeutic potential of Sotatercept in addressing pulmonary hypertension associated with IPF.

MATERIALS AND METHODS

We conducted a comprehensive literature review of relevant studies on IPF management. We searched electronic databases, including PubMed, Scopus, Embase, and Web of science.

RESULTS

The two Food and Drug Administration-approved drugs for IPF, Pirfenidone, and Nintedanib, have been pivotal in slowing disease progression, yet experimental evidence suggests that Saracatinib surpasses their efficacy. Preclinical trials investigating the potential of Saracatinib, a tyrosine kinase inhibitor, have shown to be more effective than current IPF drugs in slowing disease progression in preclinical studies. Also, Sotatercept,a fusion protein, has been shown to reduce pulmonary vascular resistance and improve exercise tolerance in patients with PH associated with IPF in clinical trials.

CONCLUSIONS

The advancements discussed in this review hold the promise of improving the quality of life for IPF patients and enhancing our understanding of this condition. There remains a need for further research to confirm the efficacy and safety of new IPF treatments and to develop more effective strategies for managing exacerbations.

Increased Levels of Galectin-3 in Critical COVID-19

Severe COVID-19 is related to hyperinflammation and multiple organ injury, including respiratory failure, thus requiring intensive care unit (ICU) admission. Galectin-3, a carbohydrate-binding protein exhibiting pleiotropic effects, has been previously recognized to participate in inflammation, the immune response to infections and fibrosis. The aim of this study was to evaluate the relationship between galectin-3 and the clinical severity of COVID-19, as well as assess the prognostic accuracy of galectin-3 for the probability of ICU mortality. The study included 235 COVID-19 patients with active disease, treated in two different Greek hospitals in total. Our results showed that median galectin-3 serum levels on admission were significantly increased in critical COVID-19 patients (7.2 ng/mL), as compared to the median levels of patients with less severe disease (2.9 ng/mL, p = 0.003). Galectin-3 levels of the non-survivors hospitalized in the ICU were significantly higher than those of the survivors (median 9.1 ng/mL versus 5.8 ng/mL, p = 0.001). The prognostic accuracy of galectin-3 for the probability of ICU mortality was studied with a receiver operating characteristic (ROC) curve and a multivariate analysis further demonstrated that galectin-3 concentration at hospital admission could be assumed as an independent risk factor associated with ICU mortality. Our results were validated with galectin-3 measurements in a second patient cohort from a different Greek university hospital. Our results, apart from strongly confirming and advancing previous knowledge with two patient cohorts, explore the possibility of predicting ICU mortality, which could provide useful information to clinicians. Therefore, galectin-3 seems to establish its involvement in the prognosis of hospitalized COVID-19 patients, suggesting that it could serve as a promising biomarker in critical COVID-19.

The Role of Galectin-3 in Retinal Degeneration and Other Ocular Diseases: A Potential Novel Biomarker and Therapeutic Target

Galectin-3 is the most studied member of the Galectin family, with a large range of mediation in biological activities such as cell growth, proliferation, apoptosis, differentiation, cell adhesion, and tissue repair, as well as in pathological processes such as inflammation, tissue fibrosis, and angiogenesis. As is known to all, inflammation, aberrant cell apoptosis, and neovascularization are the main pathophysiological processes in retinal degeneration and many ocular diseases. Therefore, the review aims to conclude the role of Gal3 in the retinal degeneration of various diseases as well as the occurrence and development of the diseases and discuss its molecular mechanisms according to research in systemic diseases. At the same time, we summarized the predictive role of Gal3 as a biomarker and the clinical application of its inhibitors to discuss the possibility of Gal3 as a novel target for the treatment of ocular diseases.

Differential Transcriptomic Signatures of Small Airway Cell Cultures Derived from IPF and COVID-19-Induced Exacerbation of Interstitial Lung Disease

Idiopathic pulmonary fibrosis (IPF) is a pathological condition wherein lung injury precipitates the deposition of scar tissue, ultimately leading to a decline in pulmonary function. Existing research indicates a notable exacerbation in the clinical prognosis of IPF patients following infection with COVID-19. This investigation employed bulk RNA-sequencing methodologies to describe the transcriptomic profiles of small airway cell cultures derived from IPF and post-COVID fibrosis patients. Differential gene expression analysis unveiled heightened activation of pathways associated with microtubule assembly and interferon signaling in IPF cell cultures. Conversely, post-COVID fibrosis cell cultures exhibited distinctive characteristics, including the upregulation of pathways linked to extracellular matrix remodeling, immune system response, and TGF-β1 signaling. Notably, BMP signaling levels were elevated in cell cultures derived from IPF patients compared to non-IPF control and post-COVID fibrosis samples. These findings underscore the molecular distinctions between IPF and post-COVID fibrosis, particularly in the context of signaling pathways associated with each condition. A better understanding of the underlying molecular mechanisms holds the promise of identifying potential therapeutic targets for future interventions in these diseases.

Antibody-mediated neutralization of galectin-3 as a strategy for the treatment of systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune, inflammatory and fibrotic disease with limited treatment options. Developing new therapies is therefore crucial to address patient needs. To this end, we focused on galectin-3 (Gal-3), a lectin known to be associated with several pathological processes seen in SSc. Using RNA sequencing of whole-blood samples in a cross-sectional cohort of 249 patients with SSc, Gal-3 and its interactants defined a strong transcriptomic fingerprint associated with disease severity, pulmonary and cardiac malfunctions, neutrophilia and lymphopenia. We developed new Gal-3 neutralizing monoclonal antibodies (mAb), which were then evaluated in a mouse model of hypochlorous acid (HOCl)-induced SSc. We show that two of these antibodies, D11 and E07, reduced pathological skin thickening, lung and skin collagen deposition, pulmonary macrophage content, and plasma interleukin-5 and -6 levels. Moreover, E07 changed the transcriptional profiles of HOCl-treated mice, resulting in a gene expression pattern that resembled that of control mice. Similarly, pathological pathways engaged in patients with SSc were counteracted by E07 in mice. Collectively, these findings demonstrate the translational potential of Gal-3 blockade as a therapeutic option for SSc.

Molecular mechanisms of COVID-19-induced pulmonary fibrosis and epithelial-mesenchymal transition

As the outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first broke out in Hubei Province, China, at the end of 2019. It has brought great challenges and harms to global public health. SARS-CoV-2 mainly affects the lungs and is mainly manifested as pulmonary disease. However, one of the biggest crises arises from the emergence of COVID-19-induced fibrosis. At present, there are still many questions about how COVID-19 induced pulmonary fibrosis (PF) occurs and how to treat and regulate its long-term effects. In addition, as an important process of fibrosis, the effect of COVID-19 on epithelial-mesenchymal transition (EMT) may be an important factor driving PF. This review summarizes the main pathogenesis and treatment mechanisms of COVID-19 related to PF. Starting with the basic mechanisms of PF, such as EMT, transforming growth factor-β (TGF-β), fibroblasts and myofibroblasts, inflammation, macrophages, innate lymphoid cells, matrix metalloproteinases and tissue inhibitors of metalloproteinases, hedgehog pathway as well as Notch signaling. Further, we highlight the importance of COVID-19-induced EMT in the process of PF and provide an overview of the related molecular mechanisms, which will facilitate future research to propose new clinical therapeutic solutions for the treatment of COVID-19-induced PF.

Targeting galectin-3 in inflammatory and fibrotic diseases

Galectin (Gal)-3 is a β-galactoside-binding lectin emerging as a key player in cardiac, hepatic, renal, and pulmonary fibrosis and inflammation, respiratory infections caused by COVID-19, and neuroinflammatory disorders. Here, we review recent information highlighting Gal-3 as a relevant therapeutic target in these specific disease conditions. While a causal link was difficult to establish until now, we discuss how recent strategic breakthroughs allowed us to identify new-generation Gal-3 inhibitors with improved potency, selectivity, and bioavailability, and report their usefulness as valuable tools for proof-of-concept studies in various preclinical models of the aforementioned diseases, with emphasis on those actually in clinical stages. We also address critical views and suggestions intended to expand the therapeutic opportunities provided by this complex target.

Cardiac Biomarkers and Their Role in Identifying Increased Risk of Cardiovascular Complications in COVID-19 Patients

Cardiovascular disease (CVD) is a global health concern, causing significant morbidity and mortality. Both lifestyle and genetics influence the development of CVD. It is often diagnosed late, when the treatment options are limited. Early diagnosis of CVD with help of biomarkers is necessary to prevent adverse outcomes. SARS-CoV-2 infection can cause cardiovascular complications even in patients with no prior history of CVD. This review highlights cardiovascular biomarkers, including novel ones, and their applications as diagnostic and prognostic markers of cardiovascular complications related to SARS-CoV-2 infection. Patients with severe SARS-CoV-2 infection were shown to have elevated levels of cardiac biomarkers, namely N-terminal pro-brain natriuretic peptide (NT-pro-BNP), creatine kinase-myocardial band (CK-MB), and troponins, indicating acute myocardial damage. These biomarkers were also associated with higher mortality rates and therefore should be used throughout COVID-19 patient care to identify high-risk patients promptly to optimize their outcomes. Additionally, microRNAs (miRNAs) are also considered as potential biomarkers and predictors of cardiac and vascular damage in SARS-CoV-2 infection. Identifying molecular pathways contributing to cardiovascular manifestations in COVID-19 is essential for development of early biomarkers, identification of new therapeutic targets, and better prediction and management of cardiovascular outcomes.

Untapping the Potential of Astragaloside IV in the Battle Against Respiratory Diseases

Respiratory diseases are an emerging public health concern, that pose a risk to the global community. There, it is essential to establish effective treatments to reduce the global burden of respiratory diseases. Astragaloside IV (AS-IV) is a natural saponin isolated from Radix astragali (Huangqi in Chinese) used for thousands of years in Chinese medicine. This compound has become increasingly popular due to its potential anti-inflammatory, antioxidant, and anticancer properties. In the last decade, accumulated evidence has indicated the AS-IV protective effect against respiratory diseases. This article presents a current understanding of AS-IV roles and mechanisms in combatting respiratory diseases. The ability of the agent to suppress oxidative stress, cell proliferation, and epithelial-mesenchymal transition (EMT), to attenuate inflammatory responses, and modulate programmed cell death (PCD) will be discussed. This review highlights the current challenges in respiratory diseases and recommendations to improve disease management.

Evaluating the affinity and kinetics of small molecule glycomimetics for human and mouse galectin-3 using surface plasmon resonance

Galectin-3 is a beta-galactoside-binding mammalian lectin that is one of a 15-member galectin family that can bind several cell surface glycoproteins via its carbohydrate recognition domain (CRD). As a result, it can influence a range of cellular processes including cell activation, adhesion and apoptosis. Galectin-3 has been implicated in various diseases, including fibrotic disorders and cancer, and is now being therapeutically targeted by both small and large molecules. Historically, the screening and triaging of small molecule glycomimetics that bind to the galectin-3 CRD has been completed in fluorescence polarisation (FP) assays to determine KD values. Surface plasmon resonance (SPR) has not been widely used for compound screening and in this study it was used to compare human and mouse galectin-3 affinity measures between FP and SPR, as well as investigate compound kinetics. The KD estimates for a set of compounds selected from mono- and di-saccharides with affinities across a 550-fold range, correlated well between FP and SPR assay formats for both human and mouse galectin-3. Increases in affinity for compounds binding to human galectin-3 were driven by changes in both kon and koff whilst for mouse galectin-3 this was primarily due to kon. The reduction in affinity observed between human to mouse galectin-3 was also comparable between assay formats. SPR has been shown to be a viable alternative to FP for early drug discovery screening and determining KD values. In addition, it can also provide early kinetic characterisation of small molecule galectin-3 glycomimetics with robust kon and koff values generated in a high throughput manner.

Galectin-3: therapeutic targeting in liver disease

INTRODUCTION

The rising incidence of liver diseases is a worldwide healthcare concern. However, the therapeutic options to manage chronic inflammation and fibrosis, the processes at the basis of morbidity and mortality of liver diseases, are very limited. Galectin 3 (Gal-3) is a protein implicated in fibrosis in multiple organs. Several Gal-3 inhibitors are currently in clinical development.

AREAS COVERED

This review describes our current understanding of the role of Gal-3 in chronic liver diseases, with special emphasis on fibrosis. Also, we review therapeutic advances based on Gal-3 inhibition, describing drug properties and their current status in clinical research.

EXPERT OPINION

Currently, the known effects of Gal-3 point to a direct activation of the NLRP3 inflammasome leading to its activation in liver macrophages and activated macrophages play a key role in tissue fibrogenesis. However, more research is needed to elucidate the role of Gal-3 in the different activation pathways, dissecting the intracellular and extracellular mechanisms of Gal-3, and its role in pathogenesis. Gal-3 could be a target for early therapy of numerous hepatic diseases and, given the lack of therapeutic options for liver fibrosis, there is a strong pharmacologic potential for Gal-3-based therapies.

Intra- and Intertumoral Microglia/Macrophage Infiltration and Their Associated Molecular Signature Is Highly Variable in Canine Oligodendroglioma: A Preliminary Evaluation

The goal of this study was to define the glioma-associated microglia/macrophage (GAM) response and associated molecular landscape in canine oligodendrogliomas. Here, we quantified the intratumoral GAM density of low- and high-grade oligodendrogliomas compared to that of a normal brain, as well as the intratumoral concentration of several known GAM-derived pro-tumorigenic molecules in high-grade oligodendrogliomas compared to that in a normal brain. Our analysis demonstrated marked intra- and intertumoral heterogeneity of GAM infiltration. Correspondingly, we observed significant variability in the intratumoral concentrations of several GAM-associated molecules, unlike what we previously observed in high-grade astrocytomas. However, high-grade oligodendroglioma tumor homogenates (n = 6) exhibited an increase in the pro-tumorigenic molecules hepatocyte growth factor receptor (HGFR) and vascular endothelial growth factor (VEGF), as we observed in high-grade astrocytomas. Moreover, neoplastic oligodendrocytes displayed robust expression of GAL-3, a chimeric galectin implicated in driving immunosuppression in human glioblastoma. While this work identifies shared putative therapeutic targets across canine glioma subtypes (HGFR, GAL-3), it highlights several key differences in the immune landscape. Therefore, a continued effort to develop a comprehensive understanding of the immune microenvironment within each subtype is necessary to inform therapeutic strategies going forward.

Clinicopathological Outlines of Post-COVID-19 Pulmonary Fibrosis Compared with Idiopathic Pulmonary Fibrosis

This review brings together the current knowledge regarding the risk factors and the clinical, radiologic, and histological features of both post-COVID-19 pulmonary fibrosis (PCPF) and idiopathic pulmonary fibrosis (IPF), describing the similarities and the disparities between these two diseases, using numerous databases to identify relevant articles published in English through October 2022. This review would help clinicians, pathologists, and researchers make an accurate diagnosis, which can help identify the group of patients selected for anti-fibrotic therapies and future therapeutic perspectives.