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This is the first in a series of interviews with those closely tied to the Hachette v. Internet Archive lawsuit. In March 2023, the court ruled against the Internet Archive and its use of the Emergency Lending Library causing a ripple throughout the library and education fields. Below, find the answers to some of the questions that the case elicited by JCEL contributors and copyright scholars Dave Hansen, Michelle Wu, and Kyle Courtney.

In this interview, Dr. Thomas discusses the relationship between race and copyright. This conversation with Tucker Taylor of the Journal of Copyright in Education and Librarianship covers Dr. Thomas’s path to copyright education as well as her work at Connecting Communities Digital Initiative (CCDI) at the Library of Congress. Dr. Thomas details the interaction of race and copyright, and how it relates to librarianship and education. She also details ideas for librarians and educators to help improve our current situation.

In this interview, Jacob Rooksby discusses his work and research in intellectual property and higher education law, including a critical examination of the role of copyright on the modern university campus. The conversation, with the Journal of Copyright in Education and Librarianship’s (JCEL) Micah Zeller and Tucker Taylor, covers trends concerning student entrepreneurship, faculty ownership, donor-imposed restrictions in special collections, and why everyone involved—from trustees, administrators, instructors, students, and library staff—should care and know how law and policies affect their interests. The discussion draws on Rooksby’s 2016 book, The Branding of the American Mind: How Universities Capture, Manage, and Monetize Intellectual Property and Why It Matters, which describes problematic practices of institutions, opportunities for those working in this space, and how intellectual property issues connect to our moral expectations for higher education. Professor Rooksby also flags areas for readers to keep an eye on in the future.

Peter Jaszi, copyright expert, lawyer, professor and author, was interviewed by the editors of the Journal of Copyright in Education and Librarainship on his carreer, influences, and copyright law, including what the future may hold for libraries and copyright. He also discusses the Codes of Best Practices for Fair Use, and gives advice for librarians who work with copyright.

An Editorial Introduction

Background: Alpha-1 antitrypsin (AAT)-deficient individuals have a greater risk for developing COPD than individuals with normal AAT levels., Methods: This was a double-blind, randomised, parallel group, placebo-controlled trial to examine the safety and tolerability of "Kamada-AAT for Inhalation" (inhaled AAT) in subjects with AAT deficiency, and to explore its effect on AAT and biomarkers in the lung epithelial lining fluid (ELF). 36 patients with severe AAT deficiency were randomised 2:1 to receive 80 mg or 160 mg inhaled AAT or placebo once daily for 12 weeks. The primary outcomes were AAT and antineutrophil elastase capacity (ANEC) in bronchoalveolar lavage and plasma after treatment. Secondary outcomes included safety, levels of normal M-type AAT in the plasma and concentrations of AAT, neutrophil elastase (NE), AAT-NE complexes and neutrophil count in the ELF., Results: 12 weeks of active treatment significantly increased AAT, ANEC and AAT-NE complexes in the ELF. Mean antigenic AAT levels in the ELF were restored to 5.2±2.3 μM in the 80 mg arm and to 17.7±2 μM in the 160 mg arm. Both doses significantly restored AAT antiprotease activity within the lung and reduced NE levels. M-specific AAT levels in plasma increased in a dose-dependent manner. A clinically meaningful reduction in ELF neutrophil % was observed in the 80 mg arm. AAT for inhalation was well tolerated., Conclusions: Inhaled AAT restores protease-antiprotease homoeostasis and may represent a safe and effective therapy., Competing Interests: Conflict of interest: N. Tov and N. Alagem are Kamada employees. All other authors have no conflict of interest to declare., (Copyright ©The authors 2025.)

Bleeding within the pleural space may result in persistent clot formation called retained hemothorax (RH). RH is prone to organization, which compromises effective drainage, leading to lung restriction and dyspnea. Intrapleural fibrinolytic therapy is used to clear the persistent organizing clot in lieu of surgery, but fibrinolysin selection, delivery strategies, and dosing have yet to be identified. We used a recently established rabbit model of RH to test whether intrapleural delivery of single-chain urokinase (scuPA) can most effectively clear RH. scuPA, or single-chain tissue plasminogen activator (sctPA), was delivered via thoracostomy tube on day 7 as either one or two doses 8 h apart. Pleural clot dissolution was assessed using transthoracic ultrasonography, chest computed tomography, two-dimensional and clot displacement measurements, and gross analysis. Two doses of scuPA (1 mg/kg) were more effective than a bolus dose of 2 mg/kg in resolving RH and facilitating drainage of pleural fluids (PF). Red blood cell counts in the PF of scuPA, or sctPA-treated rabbits were comparable, and no gross intrapleural hemorrhage was observed. Both fibrinolysins were equally effective in clearing clots and promoting pleural drainage. Biomarkers of inflammation and organization were likewise comparable in PF from both groups. The findings suggest that single-agent therapy may be effective in clearing RH; however, the clinical advantage of intrapleural scuPA remains to be established by future clinical trials.

The pathology of atherosclerosis, a leading cause of mortality in patients with cardiovascular disease, involves inflammatory phenotypic changes in vascular endothelial cells. This study explored the role of the dedicator of cytokinesis (DOCK)-2 protein in atherosclerosis. Mice with deficiencies in low-density lipoprotein receptor and Dock2 (Ldlr -/- Dock2 -/- ) and controls (Ldlr -/- ) were fed a high-fat diet (HFD) to induce atherosclerosis. In controls, Dock2 was increased in atherosclerotic lesions, with increased intercellular adhesion molecule (Icam)-1 and vascular cell adhesion molecule (Vcam)-1, after HFD for 4 weeks. Ldlr -/- Dock2 -/- mice exhibited significantly decreased oil red O staining in both aortic roots and aortas compared to that in controls after HFD for 12 weeks. In control mice and in humans, Dock2 was highly expressed in the ECs of atherosclerotic lesions. Dock2 deficiency was associated with attenuation of Icam-1, Vcam-1, and monocyte chemoattractant protein (Mcp)-1 in the aortic roots of mice fed HFD. Findings in human vascular ECs in vitro suggested that DOCK2 was required in TNF-α-mediated expression of ICAM-1/VCAM-1/MCP-1. DOCK2 knockdown was associated with attenuated NF-κB phosphorylation with TNF-α, partially accounting for DOCK2-mediated vascular inflammation. With DOCK2 knockdown in human vascular ECs, TNF-α-mediated VCAM-1 promoter activity was inhibited. The findings from this study suggest the novel concept that DOCK2 promotes the pathogenesis of atherosclerosis by modulating inflammation in vascular ECs., (Copyright © 2024 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

During the progression of pleural fibrosis, pleural mesothelial cells (PMCs) undergo a phenotype switching process known as mesothelial-mesenchymal transition (MesoMT). During MesoMT, transformed PMCs become myofibroblasts that produce increased extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1) that is critical to develop fibrosis. Here, we studied the mechanism that regulates FN1 expression in myofibroblasts derived from human pleural mesothelial cells (HPMCs). We found that myocardin (Myocd), a transcriptional coactivator of serum response factor (SRF) and a master regulator of smooth muscle and cardiac muscle differentiation, strongly controls FN1 gene expression. Myocd gene silencing markedly inhibited FN1 expression. FN1 promoter analysis revealed that deletion of the Smad3-binding element diminished FN1 promoter activity, whereas deletion of the putative SRF-binding element increased FN1 promoter activity. Smad3 gene silencing decreased FN1 expression, whereas SRF gene silencing increased FN1 expression. Moreover, SRF competes with Smad3 for binding to Myocd. These results indicate that Myocd activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression in HPMCs. In HPMCs, TGF-β induced Smad3 nuclear localization, and the proximity ligation signal between Myocd and Smad3 was markedly increased after TGF-β stimulation at nucleus, suggesting that TGF-β facilitates nuclear translocation of Smad3 and interaction between Smad3 and Myocd. Moreover, Myocd and Smad3 were coimmunoprecipitated and isolated Myocd and Smad3 proteins directly bound each other. Chromatin immunoprecipitation assays revealed that Myocd interacts with the FN1 promoter at the Smad3-binding consensus sequence. The results indicate that Myocd regulates FN1 gene activation through interaction and activation of the Smad3 transcription factor. NEW & NOTEWORTHY During phenotype switching from mesothelial to mesenchymal, pleural mesothelial cells (PMCs) produce extracellular matrix (ECM) proteins, including collagen and fibronectin (FN1), critical components in the development of fibrosis. Here, we found that myocardin, a transcriptional coactivator of serum response factor (SRF), strongly activates FN1 expression through Smad3, whereas SRF inhibits FN1 expression. This study provides insights about the regulation of FN1 that could lead to the development of novel interventional approaches to prevent pleural fibrosis.

During the development of pleural fibrosis, pleural mesothelial cells (PMCs) undergo phenotypic switching from differentiated mesothelial cells to mesenchymal cells (MesoMT). Here, we investigated how external stimuli such as TGF-β induce HPMC-derived myofibroblast differentiation to facilitate the development of pleural fibrosis. TGF-β significantly increased di-phosphorylation but not mono-phosphorylation of myosin II regulatory light chain (RLC) in HPMCs. An increase in RLC di-phosphorylation was also found at the pleural layer of our carbon black bleomycin (CBB) pleural fibrosis mouse model, where it showed filamentous localization that coincided with alpha smooth muscle actin (αSMA) in the cells in the pleura. Among the protein kinases that can phosphorylate myosin II RLC, ZIPK (zipper-interacting kinase) protein expression was significantly augmented after TGF-β stimulation. Furthermore, ZIPK gene silencing attenuated RLC di-phosphorylation, suggesting that ZIPK is responsible for di-phosphorylation of myosin II in HPMCs. Although TGF-β significantly increased the expression of ZIP kinase protein, the change in ZIP kinase mRNA was marginal, suggesting a posttranscriptional mechanism for the regulation of ZIP kinase expression by TGF-β. ZIPK gene knockdown (KD) also significantly reduced TGF-β-induced upregulation of αSMA expression. This finding suggests that siZIPK attenuates myofibroblast differentiation of HPMCs. siZIPK diminished TGF-β-induced contractility of HPMCs consistent with siZIPK-induced decrease in the di-phosphorylation of myosin II RLC. The present results implicate ZIPK in the regulation of the contractility of HPMC-derived myofibroblasts, phenotype switching, and myofibroblast differentiation of HPMCs. NEW & NOTEWORTHY Here, we highlight that ZIP kinase is responsible for di-phosphorylation of myosin light chain, which facilitates stress fiber formation and actomyosin-based cell contraction during mesothelial to mesenchymal transition in human pleural mesothelial cells. This transition has a significant impact on tissue remodeling and subsequent stiffness of the pleura. This study provides insight into a new therapeutic strategy for the treatment of pleural fibrosis.

The surface spike (S) glycoprotein mediates cell entry of SARS-CoV-2 into the host through fusion at the plasma membrane or endocytosis. Omicron lineages/sublineages have acquired extensive mutations in S to gain transmissibility advantages and altered antigenicity. The fusogenicity, antigenicity, and evasion of Omicron subvariants have been extensively investigated at unprecedented speed to align with the mutation rate of S. Cells that overexpress receptors/cofactors are mostly used as hosts to amplify infection sensitivity to tested variants. However, systematic cell entry comparisons of most prior dominant Omicron subvariants using human lung epithelium cells are yet to be well-studied. Here, with human bronchial epithelium BEAS-2B cells as the host, we compared single-round virus-to-cell entry and cell-to-cell fusion of Omicron BA.1, BA.5, BQ.1.1, CH.1.1, XBB.1.5, and XBB.1.16 based upon split NanoLuc fusion readout assays and the S-pseudotyped lentivirus system. Virus-to-cell entry of tested S variants exhibited cell-type dependence. The parental Omicron BA.1 required more time to develop full entry to HEK293T-ACE2-TMPRSS2 than BEAS-2B cells. Compared to unchanged P681, S-cleavage constructs of P681H/R did not have any noticeable advantages in cell entry. Omicron BA.1 and its descendants entered BEAS-2B cells more efficiently than D614G, and it was slightly less or comparable to that of Delta. Serine protease-pretreated Omicron subvariants enhanced virus-to-cell entry in a dose-dependent manner, suggesting fusion at the plasma membrane persists as a productive cell entry route. Spike-mediated cell-to-cell fusion and total S1/S2 processing of Omicron descendants were similar. Our results indicate no obvious entry or fusion advantages of recent Omicron descendants over preceding variants since Delta, thus supporting immune evasion conferred by antigenicity shifts due to altered S sequences as probably the primary viral fitness driver.

Progressive lung scarring because of persistent pleural organization often results in pleural fibrosis (PF). This process affects patients with complicated parapneumonic pleural effusions, empyema, and other pleural diseases prone to loculation. In PF, pleural mesothelial cells undergo mesomesenchymal transition (MesoMT) to become profibrotic, characterized by increased expression of α-smooth muscle actin and matrix proteins, including collagen-1. In our previous study, we showed that blocking PI3K/Akt signaling inhibits MesoMT induction in human pleural mesothelial cells (HPMCs) (1). However, the downstream signaling pathways leading to MesoMT induction remain obscure. Here, we investigated the role of mTOR complexes (mTORC1/2) in MesoMT induction. Our studies show that activation of the downstream mediator mTORC1/2 complex is, likewise, a critical component of MesoMT. Specific targeting of mTORC1/2 complex using pharmacological inhibitors such as INK128 and AZD8055 significantly inhibited transforming growth factor β (TGF-β)-induced MesoMT markers in HPMCs. We further identified the mTORC2/Rictor complex as the principal contributor to MesoMT progression induced by TGF-β. Knockdown of Rictor, but not Raptor, attenuated TGF-β-induced MesoMT in these cells. In these studies, we further show that concomitant activation of the SGK1/NDRG1 signaling cascade is essential for inducing MesoMT. Targeting SGK1 and NDRG1 with siRNA and small molecular inhibitors attenuated TGF-β-induced MesoMT in HPMCs. Additionally, preclinical studies in our Streptococcus pneumoniae- mediated mouse model of PF showed that inhibition of mTORC1/2 with INK128 significantly attenuated the progression of PF in subacute and chronic injury. In conclusion, our studies demonstrate that mTORC2/Rictor-mediated activation of SGK1/NDRG1 is critical for MesoMT induction and that targeting this pathway could inhibit or even reverse the progression of MesoMT and PF.

Interstitial lung diseases can result in poor patient outcomes, especially in idiopathic pulmonary fibrosis (IPF), a severe interstitial lung disease with unknown causes. The lack of treatment options requires further understanding of the pathological process/mediators. Membrane-associated RING-CH 8 (MARCH8) has been implicated in immune function regulation and inflammation, however, its role in the development of pulmonary fibrosis and particularly the fibroblast to myofibroblast transition (FMT) remains a gap in existing knowledge. In this study, we demonstrated decreased MARCH8 expression in patients with IPF compared with non-PF controls and in bleomycin-induced PF. TGF-β dose- and time-dependently decreased MARCH8 expression in normal and IPF human lung fibroblast (HLFs), along with induction of FMT markers α-SMA, collagen type I (Col-1), and fibronectin (FN). Interestingly, overexpression of MARCH8 significantly suppressed TGF-β-induced expression of α-SMA, Col-1, and FN. By contrast, the knockdown of MARCH8 using siRNA upregulated basal expression of α-SMA/Col-1/FN. Moreover, MARCH8 knockdown enhanced TGF-β-induced FMT marker expression. These data clearly show that MARCH8 is a critical "brake" for FMT and potentially affects PF. We further found that TGF-β suppressed MARCH8 mRNA expression and the proteasome inhibitor MG132 failed to block MARCH8 decrease induced by TGF-β. Conversely, TGF-β decreases mRNA levels of MARCH8 in a dose- and time-dependent manner, suggesting the transcriptional regulation of MARCH8 by TGF-β. Mechanistically, MARCH8 overexpression suppressed TGF-β-induced Smad2/3 phosphorylation, which may account for the observed effects. Taken together, this study demonstrated an unrecognized role of MARCH8 in negatively regulating FMT and profibrogenic responses relevant to interstitial lung diseases. NEW & NOTEWORTHY MARCH8 is an important modulator of inflammation, immunity, and other cellular processes. We found that MARCH8 expression is downregulated in the lungs of patients with idiopathic pulmonary fibrosis (IPF) and experimental models of pulmonary fibrosis. Furthermore, TGF-β1 decreases MARCH8 transcriptionally in human lung fibroblasts (HLFs). MARCH8 overexpression blunts TGF-β1-induced fibroblast to myofibroblast transition while knockdown of MARCH8 drives this profibrotic change in HLFs. The findings support further exploration of MARCH8 as a novel target in IPF.

Bromodomain and extra-terminal domain (BET) proteins are epigenetic modulators that regulate gene transcription through interacting with acetylated lysine residues of histone proteins. BET proteins have multiple roles in regulating key cellular functions such as cell proliferation, differentiation, inflammation, oxidative and redox balance, and immune responses. As a result, BET proteins have been found to be actively involved in a broad range of human lung diseases including acute lung inflammation, asthma, pulmonary arterial hypertension, pulmonary fibrosis, and chronic obstructive pulmonary disease (COPD). Due to the identification of specific small molecular inhibitors of BET proteins, targeting BET in these lung diseases has become an area of increasing interest. Emerging evidence has demonstrated the beneficial effects of BET inhibitors in preclinical models of various human lung diseases. This is, in general, largely related to the ability of BET proteins to bind to promoters of genes that are critical for inflammation, differentiation, and beyond. By modulating these critical genes, BET proteins are integrated into the pathogenesis of disease progression. The intrinsic histone acetyltransferase activity of bromodomain-containing protein 4 (BRD4) is of particular interest, seems to act independently of its bromodomain binding activity, and has implication in some contexts. In this review, we provide a brief overview of the research on BET proteins with a focus on BRD4 in several major human lung diseases, the underlying molecular mechanisms, as well as findings of targeting BET proteins using pharmaceutical inhibitors in different lung diseases preclinically.

Respiratory viruses pose a continuing and substantive threat to human health globally. Host innate and adaptive immune responses are the critical antiviral defense mechanisms to control viral replication and spread. The present study is designed to determine the role of transcription factor Runx3 in the host immune response to influenza A virus (IAV) infection. As Runx3 is required for embryonic development, we generated an inducible Runx3 global knockout (KO) mouse model and found that Runx3 KO in adult C57BL/6 mice minimally affected thymic function under normal conditions and survival was at least 250 days post Runx3 deletion. We applied the mouse model to IAV infection and found that Runx3 KO resulted in a huge reduction (>85%) in numbers of total and antigen-specific pulmonary CD8 + cytotoxic T cells during IAV infection, while it had a minor effect on pulmonary generation of CD4 + T cells. To our surprise, this general KO of Runx3 did not significantly alter viral clearance and animal survival following IAV infection. Interestingly, we found that Runx3 KO significantly increased the numbers of pulmonary innate immune cells such as macrophages and neutrophils and the production of pro-inflammatory cytokines during IAV infection. We further found that Runx3 was strongly detected in CCR2 + immune cells in IAV-infected mouse lungs and was induced in activated macrophages and dendritic cells (DCs). As pulmonary CD8 + cytotoxic T cells play a central role in the clearance of IAV, our findings suggest that Runx3 KO may enhance host innate immunity to compensate for the loss of pulmonary CD8 + cytotoxic T cells during IAV infection., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hao, Kundu, Shetty, Tucker, Idell and Tang.)

Idiopathic pulmonary fibrosis (IPF) is the most common chronic interstitial lung disease and is characterized by progressive scarring of the lung. Transforming growth factor-β (TGF-β) signaling plays an essential role in IPF and drives fibroblast to myofibroblast transition (FMT). Dedicator of cytokinesis 2 (DOCK2) is known to regulate diverse immune functions by activating Rac and has been recently implicated in pleural fibrosis. We now report a novel role of DOCK2 in pulmonary fibrosis development by mediating FMT. In primary normal and IPF human lung fibroblasts (HLFs), TGF-β induced DOCK2 expression concurrent with FMT markers, smooth muscle α-actin (α-SMA), collagen-1, and fibronectin. Knockdown of DOCK2 significantly attenuated TGF-β-induced expression of these FMT markers. In addition, we found that the upregulation of DOCK2 by TGF-β is dependent on both Smad3 and ERK pathways as their respective inhibitors blocked TGF-β-mediated induction. TGF-β also stabilized DOCK2 protein, which contributes to increased DOCK2 expression. In addition, DOCK2 was also dramatically induced in the lungs of patients with IPF and in bleomycin, and TGF-β induced pulmonary fibrosis in C57BL/6 mice. Furthermore, increased lung DOCK2 expression colocalized with the FMT marker α-SMA in the bleomycin-induced pulmonary fibrosis model, implicating DOCK2 in the regulation of lung fibroblast phenotypic changes. Importantly, DOCK2 deficiency also attenuated bleomycin-induced pulmonary fibrosis and α-SMA expression. Taken together, our study demonstrates a novel role of DOCK2 in pulmonary fibrosis by modulating FMT and suggests that targeting DOCK2 may present a potential therapeutic strategy for the prevention or treatment of IPF.

Pleural mesothelial cells (PMCs) can become myofibroblasts via mesothelial-mesenchymal transition (MesoMT) and contribute to pleural organization, fibrosis, and rind formation. However, how these transformed mesothelial cells contribute to lung fibrosis remains unclear. Here, we investigated the mechanism of contractile myofibroblast differentiation of PMCs. Transforming growth factor-β (TGF-β) induced marked upregulation of calponin 1 expression, which was correlated with notable cytoskeletal rearrangement in human PMCs (HPMCs) to produce stress fibers. Downregulation of calponin 1 expression reduced stress fiber formation. Interestingly, induced stress fibers predominantly contain α-smooth muscle actin (αSMA) associated with calponin 1 but not β-actin. Calponin 1-associated stress fibers also contained myosin II and α-actinin. Furthermore, focal adhesions were aligned with the produced stress fibers. These results suggest that calponin 1 facilitates formation of stress fibers that resemble contractile myofibrils. Supporting this notion, TGF-β significantly increased the contractile activity of HPMCs, an effect that was abolished by downregulation of calponin 1 expression. We infer that differentiation of HPMCs to contractile myofibroblasts facilitates stiffness of scar tissue in pleura to promote pleural fibrosis (PF) and that upregulation of calponin 1 plays a central role in this process.

Programmed death ligand-1 (PD-L1) is an immune checkpoint protein that has been linked with idiopathic pulmonary fibrosis (IPF) and fibroblast to myofibroblast transition (FMT). However, it remains largely unclear how PD-L1 mediates this process. We found significantly increased PD-L1 in the lungs of idiopathic pulmonary fibrosis patients and mice with pulmonary fibrosis induced by bleomycin and TGF-β. In primary human lung fibroblasts (HLFs), TGF-β induced PD-L1 expression that is dependent on both Smad3 and p38 pathways. PD-L1 knockdown using siRNA significantly attenuated TGF-β-induced expression of myofibroblast markers α-SMA, collagen-1, and fibronectin in normal and IPF HLFs. Further, we found that PD-L1 interacts with Smad3, and TGF-β induces their interaction. Interestingly, PD-L1 knockdown reduced α-SMA reporter activity induced by TGF-β in HLFs, suggesting that PD-L1 might act as a co-factor of Smad3 to promote target gene expression. TGF-β treatment also phosphorylates GSK3β and upregulates β-catenin protein levels. Inhibiting β-catenin signaling with the pharmaceutical inhibitor ICG001 significantly attenuated TGF-β-induced FMT. PD-L1 knockdown also attenuated TGF-β-induced GSK3β phosphorylation/inhibition and β-catenin upregulation, implicating GSK3β/β-catenin signaling in PD-L1-mediated FMT. Collectively, our findings demonstrate that fibroblast PD-L1 may promote pulmonary fibrosis through both Smad3 and β-catenin signaling and may represent a novel interventional target for IPF., (© 2022. The Author(s).)

Necroptosis, a form of programmed lytic cell death, has emerged as a driving factor in the pathogenesis of acute lung injury (ALI). As ALI is often associated with a cytokine storm, we determined whether pro-inflammatory cytokines modulate the susceptibility of lung cells to necroptosis and which mediators dominate to control necroptosis. In this study, we pretreated/primed mouse primary lung epithelial and endothelial cells with various inflammatory mediators and assessed cell type-dependent responses to different necroptosis inducers and their underlying mechanisms. We found that interferon-γ (IFNγ) as low as 1 ng/mL preferentially promoted necroptosis and accelerated the release of damage-associated molecular patterns from primary alveolar and airway epithelial cells but not lung microvascular endothelial cells. Type-I IFNα was about fifty-fold less effective than IFNγ. Conversely, TNFα or agonists of Toll-like receptor-3 (TLR3), TLR4, TLR7 and TLR9 had a minor effect. The enhanced necroptosis in IFNγ-activated lung epithelial cells was dependent on IFNγ signaling and receptor-interacting protein kinase-3. We further showed that necroptosis effector mixed lineage kinase domain-like protein (MLKL) was predominantly induced by IFNγ, contributing to the enhanced necroptosis in lung epithelial cells. Collectively, our findings indicate that IFNγ is a potent enhancer of lung epithelial cell susceptibility to necroptosis.

Obesity is a major risk factor for lung disease development. However, little is known about the impact of chronic high-fat and high-fructose (HFHF) diet-induced obesity on lung inflammation and subsequent pulmonary fibrosis. Herein we hypothesized that dedicator of cytokinesis 2 (DOCK2) promotes a proinflammatory phenotype of lung fibroblasts (LFs) to elicit lung injury and fibrosis in chronic HFHF diet-induced obesity. An HFHF diet for 20 weeks induced lung inflammation and profibrotic changes in wild-type C57BL/6 mice. CD68 and monocyte chemoattractant protein-1 (MCP-1) expression were notably increased in the lungs of wild-type mice fed an HFHF diet. An HFHF diet further increased lung DOCK2 expression that co-localized with fibroblast-specific protein 1, suggesting a role of DOCK2 in regulating proinflammatory phenotype of LFs. Importantly, DOCK2 knockout protected mice from lung inflammation and fibrosis induced by a HFHF diet. In primary human LFs, tumor necrosis factor-α (TNF-α) and IL-1β induced DOCK2 expression concurrent with MCP-1, IL-6, and matrix metallopeptidase 2. DOCK2 knockdown suppressed TNF-α-induced expression of these molecules and activation of phosphatidylinositol 3-kinase/AKT and NF-κB signaling pathways, suggesting a mechanism of DOCK2-mediated proinflammatory and profibrotic changes in human LFs. Taken together, these findings reveal a previously unrecognized role of DOCK2 in regulating proinflammatory phenotype of LFs, potentiation of lung inflammation, and pulmonary fibrosis in chronic HFHF diet-caused obesity., (Copyright © 2022 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Mesothelial to mesenchymal transition (MesoMT) is one of the crucial mechanisms underlying pleural fibrosis, which results in restrictive lung disease. DOCK2 (dedicator of cytokinesis 2) plays important roles in immune functions; however, its role in pleural fibrosis, particularly MesoMT, remains unknown. We found that amounts of DOCK2 and the MesoMT marker α-SMA (α-smooth muscle actin) were significantly elevated and colocalized in the thickened pleura of patients with nonspecific pleuritis, suggesting the involvement of DOCK2 in the pathogenesis of MesoMT and pleural fibrosis. Likewise, data from three different pleural fibrosis models (TGF-β [transforming growth factor-β], carbon black/bleomycin, and streptococcal empyema) consistently demonstrated DOCK2 upregulation and its colocalization with α-SMA in the pleura. In addition, induced DOCK2 colocalized with the mesothelial marker calretinin, implicating DOCK2 in the regulation of MesoMT. Our in vivo data also showed that DOCK2-knockout mice were protected from Streptococcus pneumoniae -induced pleural fibrosis, impaired lung compliance, and collagen deposition. To determine the involvement of DOCK2 in MesoMT, we treated primary human pleural mesothelial cells with the potent MesoMT inducer TGF-β. TGF-β significantly induced DOCK2 expression in a time-dependent manner, together with α-SMA, collagen 1, and fibronectin. Furthermore, DOCK2 knockdown significantly attenuated TGF-β-induced α-SMA, collagen 1, and fibronectin expression, suggesting the importance of DOCK2 in TGF-β-induced MesoMT. DOCK2 knockdown also inhibited TGF-β-induced Snail upregulation, which may account for its role in regulating MesoMT. Taken together, the current study provides evidence that DOCK2 contributes to the pathogenesis of pleural fibrosis by mediating MesoMT and deposition of neomatrix and may represent a novel target for its prevention or treatment.

Pleural injury and subsequent loculation is characterized by acute injury, sustained inflammation and, when severe, pathologic tissue reorganization. While fibrin deposition is a normal part of the injury response, disordered fibrin turnover can promote pleural loculation and, when unresolved, fibrosis of the affected area. Within this review, we present a brief discussion of the current IPFT therapies, including scuPA, for the treatment of pathologic fibrin deposition and empyema. We also discuss endogenously expressed PAI-1 and how it may affect the efficacy of IPFT therapies. We further delineate the role of pleural mesothelial cells in the progression of pleural injury and subsequent pleural remodeling resulting from matrix deposition. We also describe how pleural mesothelial cells promote pleural fibrosis as myofibroblasts via mesomesenchymal transition. Finally, we discuss novel therapeutic targets which focus on blocking and/or reversing the myofibroblast differentiation of pleural mesothelial cells for the treatment of pleural fibrosis.

Pleural fibrosis (PF) is a chronic and progressive lung disease which affects approximately 30,000 people per year in the United States. Injury and sustained inflammation of the pleural space can result in PF, restricting lung expansion and impairing oxygen exchange. During the progression of pleural injury, normal pleural mesothelial cells (PMCs) undergo a transition, termed mesothelial mesenchymal transition (MesoMT). While multiple components of the fibrinolytic pathway have been investigated in pleural remodeling and PF, the role of the urokinase type plasminogen activator receptor (uPAR) is unknown. We found that uPAR is robustly expressed by pleural mesothelial cells in PF. Downregulation of uPAR by siRNA blocked TGF-β mediated MesoMT. TGF-β was also found to significantly induce uPA expression in PMCs undergoing MesoMT. Like uPAR, uPA downregulation blocked TGF-β mediated MesoMT. Further, uPAR is critical for uPA mediated MesoMT. LRP1 downregulation likewise blunted TGF-β mediated MesoMT. These findings are consistent with in vivo analyses, which showed that uPAR knockout mice were protected from S. pneumoniae-mediated decrements in lung function and restriction. Histological assessments of pleural fibrosis including pleural thickening and α-SMA expression were likewise reduced in uPAR knockout mice compared to WT mice. These studies strongly support the concept that uPAR targeting strategies could be beneficial for the treatment of PF., (© 2021. The Author(s).)

Pleural organization may occur after empyema or complicated parapneumonic effusion and can result in restrictive lung disease with pleural fibrosis (PF). Pleural mesothelial cells (PMCs) may contribute to PF through acquisition of a profibrotic phenotype, mesothelial-mesenchymal transition (MesoMT), which is characterized by increased expression of α-SMA (α-smooth muscle actin) and other myofibroblast markers. Although MesoMT has been implicated in the pathogenesis of PF, the role of the reactive oxygen species and the NOX (nicotinamide adenine dinucleotide phosphate oxidase) family in pleural remodeling remains unclear. Here, we show that NOX1 expression is enhanced in nonspecific human pleuritis and is induced in PMCs by THB (thrombin). 4-Hydroxy-2-nonenal, an indicator of reactive oxygen species damage, was likewise increased in our mouse model of pleural injury. NOX1 downregulation blocked THB- and Xa (factor Xa)-mediated MesoMT, as did pharmacologic inhibition of NOX1 with ML-171. NOX1 inhibition also reduced phosphorylation of Akt, p65, and tyrosine 216-GSK-3β, signaling molecules previously shown to be implicated in MesoMT. Conversely, ML-171 did not reverse established MesoMT. NOX4 downregulation attenuated TGF-β- and THB-mediated MesoMT. However, NOX1 downregulation did not affect NOX4 expression. NOX1- and NOX4-deficient mice were also protected in our mouse model of Streptococcus pneumoniae -mediated PF. These data show that NOX1 and NOX4 are critical determinants of MesoMT.

Streptococcus pneumoniae is the leading cause of hospital community-acquired pneumonia. Patients with pneumococcal pneumonia may develop complicated parapneumonic effusions or empyema that can lead to pleural organization and subsequent fibrosis. The pathogenesis of pleural organization and scarification involves complex interactions between the components of the immune system, coagulation, and fibrinolysis. EPCR (endothelial protein C receptor) is a critical component of the protein C anticoagulant pathway. The present study was performed to evaluate the role of EPCR in the pathogenesis of S. pneumoniae infection-induced pleural thickening and fibrosis. Our studies show that the pleural mesothelium expresses EPCR. Intrapleural instillation of S. pneumoniae impairs lung compliance and lung volume in wild-type and EPCR-overexpressing mice but not in EPCR-deficient mice. Intrapleural S. pneumoniae infection induces pleural thickening in wild-type mice. Pleural thickening is more pronounced in EPCR-overexpressing mice, whereas it is reduced in EPCR-deficient mice. Markers of mesomesenchymal transition are increased in the visceral pleura of S. pneumoniae- infected wild-type and EPCR-overexpressing mice but not in EPCR-deficient mice. The lungs of wild-type and EPCR-overexpressing mice administered intrapleural S. pneumoniae showed increased infiltration of macrophages and neutrophils, which was significantly reduced in EPCR-deficient mice. An analysis of bacterial burden in the pleural lavage, the lungs, and blood revealed a significantly lower bacterial burden in EPCR-deficient mice compared with wild-type and EPCR-overexpressing mice. Overall, our data provide strong evidence that EPCR deficiency protects against S. pneumoniae infection-induced impairment of lung function and pleural remodeling.

Pleural and parenchymal lung injury have long been characterized by acute inflammation and pathologic tissue reorganization, when severe. Although transitional matrix deposition is a normal part of the injury response, unresolved fibrin deposition can lead to pleural loculation and scarification of affected areas. Within this review, we present a brief discussion of the fibrinolytic pathway, its components, and their contribution to injury progression. We review how local derangements of fibrinolysis, resulting from increased coagulation and reduced plasminogen activator activity, promote extravascular fibrin deposition. Further, we describe how pleural mesothelial cells contribute to lung scarring via the acquisition of a profibrotic phenotype. We also discuss soluble uPAR, a recently identified biomarker of pleural injury, and its diagnostic value in the grading of pleural effusions. Finally, we provide an in-depth discussion on the clinical importance of single-chain urokinase plasminogen activator (uPA) for the treatment of loculated pleural collections.

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with a median survival of 3 years after diagnosis. Although the etiology of IPF is unknown, it is characterized by extensive alveolar epithelial cell apoptosis and proliferation of myofibroblasts in the lungs. While the origins of these myofibroblast appear to be diverse, fibroblast differentiation contributes to expansion of myofibroblasts and to disease progression. We found that agents that contribute to neomatrix formation and remodeling in pulmonary fibrosis (PF); TGF-β, Factor Xa, thrombin, plasmin and uPA all induced fibroblast/myofibroblast differentiation. These same mediators enhanced GSK-3β activation via phosphorylation of tyrosine-216 (p-Y216). Inhibition of GSK-3β signaling with the novel inhibitor 9-ING-41 blocked the induction of myofibroblast markers; α-SMA and Col-1 and reduced morphological changes of myofibroblast differentiation. In in vivo studies, the progression of TGF-β and bleomycin mediated PF was significantly attenuated by 9-ING-41 administered at 7 and 14 days respectively after the establishment of injury. Specifically, 9-ING-41 treatment significantly improved lung function (compliance and lung volumes; p < 0.05) of TGF-β adenovirus treated mice compared to controls. Similar results were found in mice with bleomycin-induced PF. These studies clearly show that activation of the GSK-3β signaling pathway is critical for the induction of myofibroblast differentiation in lung fibroblasts ex vivo and pulmonary fibrosis in vivo. The results offer a strong premise supporting the continued investigation of the GSK-3β signaling pathway in the control of fibroblast-myofibroblast differentiation and fibrosing lung injury. These data provide a strong rationale for extension of clinical trials of 9-ING-41 to patients with IPF.

Plasminogen activator inhibitor 1 (PAI-1), which is elevated in numerous disease states, has been implicated as a stress-related protein involved in the pathogenesis of depression. We measured PAI-1 in the plasma of healthy and depressed individuals and assessed plasminogen activator (PA) expression and regulation by PAI-1 in cultured normal human astrocytes (NHA). Elevated plasma PAI-1 levels were found in depressed patients. Brain tissues from depressed individuals also showed stronger expression of hippocampal PAI-1 by confocal imaging in comparison to healthy individuals. Using a lipopolysaccharide-induced inflammatory model of depression in mice, we measured PAI-1 in murine plasma and brain, by ELISA and immunohistochemistry, respectively. Similar elevations were seen in plasma but not in brain homogenates of mice exposed to LPS. We further correlated the findings with depressive behavior. Ex vivo experiments with NHA treated with proinflammatory cytokines implicated in the pathogenesis of depression showed increased PAI-1 expression. Furthermore, these studies suggest that urokinase-type plasminogen activator may serve as an astrocyte PA reservoir, able to promote cleavage of brain-derived neurotrophic factor (BDNF) during stress or inflammation. In summary, our findings confirm that derangements of PAI-1 variably occur in the brain in association with the depressive phenotype. These derangements may impede the availability of active, mature (m)BDNF and thereby promote a depressive phenotype.

Recent studies have shed new light on the role of the fibrinolytic system in the pathogenesis of pleural organization, including the mechanisms by which the system regulates mesenchymal transition of mesothelial cells and how that process affects outcomes of pleural injury. The key contribution of plasminogen activator inhibitor-1 to the outcomes of pleural injury is now better understood as is its role in the regulation of intrapleural fibrinolytic therapy. In addition, the mechanisms by which fibrinolysins are processed after intrapleural administration have now been elucidated, informing new candidate diagnostics and therapeutics for pleural loculation and failed drainage. The emergence of new potential interventional targets offers the potential for the development of new and more effective therapeutic candidates.

Pleural loculation affects about 30,000 patients annually in the United States and in severe cases can resolve with restrictive lung disease and pleural fibrosis. Pleural mesothelial cells contribute to pleural rind formation by undergoing mesothelial mesenchymal transition (MesoMT), whereby they acquire a profibrotic phenotype characterized by increased expression of α-smooth muscle actin and collagen 1. Components of the fibrinolytic pathway (urokinase plasminogen activator and plasmin) are elaborated in pleural injury and strongly induce MesoMT in vitro. These same stimuli enhance glycogen synthase kinase (GSK)-3β activity through increased phosphorylation of Tyr-216 in pleural mesothelial cells and GSK-3β mobilization from the cytoplasm to the nucleus. GSK-3β down-regulation blocked induction of MesoMT. Likewise, GSK-3β inhibitor 9ING41 blocked induction of MesoMT and reversed established MesoMT. Similar results were demonstrated in a mouse model of Streptococcus pneumoniae-induced empyema. Intraperitoneal administration of 9ING41, after the induction of pleural injury, attenuated injury progression and improved lung function (lung volume and compliance; P < 0.05 compared with untreated and vehicle controls). MesoMT marker α-smooth muscle actin was reduced in 9ING41-treated mice. Pleural thickening was also notably reduced in 9ING41-treated mice (P < 0.05). Collectively, these studies identify GSK-3β as a newly identified target for amelioration of empyema-related pleural fibrosis and provide a strong rationale for further investigation of GSK-3β signaling in the control of MesoMT and pleural injury., (Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Fibrosis involves the production of extracellular matrix proteins in tissues and is often preceded by injury or trauma. In pleural fibrosis excess collagen deposition results in pleural thickening, increased stiffness and impaired lung function. Myofibroblasts are responsible for increased collagen deposition, however the molecular mechanism of transportation of procollagen containing vesicles for secretion is unknown. Here, we studied the role of kinesin on collagen-1 (Col-1) containing vesicle transportation in human pleural mesothelial cells (HPMCs). Among a number of cargo transporting kinesins, KIF5A was notably upregulated during TGF-β induced mesothelial-mesenchymal transition (MesoMT). Using superresolution structured illumination microscopy and the DUO-Link technique, we found that KIF5A colocalized with Col-1 containing vesicles. KIF5A knock-down significantly reduced Col-1 secretion and attenuated TGF-β induced increment in Col-1 localization at cell peripheries. Live cell imaging revealed that GFP-KIF5A and mCherry-Col-1 containing vesicles moved together. Kymography showed that these molecules continuously move with a mean velocity of 0.56 μm/sec, suggesting that the movement is directional but not diffusion limited process. Moreover, KIF5A was notably upregulated along with Col-1 and α-smooth muscle actin in pleural thickening in the carbon-black bleomycin mouse model. These results support our hypothesis that KIF5A is responsible for collagen transportation and secretion from HPMCs.

Background: Pleural infection affects about 65,000 patients annually in the US and UK. In this and other forms of pleural injury, mesothelial cells (PMCs) undergo a process called mesothelial (Meso) mesenchymal transition (MT), by which PMCs acquire a profibrogenic phenotype with increased expression of α-smooth muscle actin (α-SMA) and matrix proteins. MesoMT thereby contributes to pleural organization with fibrosis and lung restriction. Current murine empyema models are characterized by early mortality, limiting analysis of the pathogenesis of pleural organization and mechanisms that promote MesoMT after infection., Methods: A new murine empyema model was generated in C57BL/6 J mice by intrapleural delivery of Streptococcus pneumoniae (D39, 3 × 10(7)-5 × 10(9) cfu) to enable use of genetically manipulated animals. CT-scanning and pulmonary function tests were used to characterize the physiologic consequences of organizing empyema. Histology, immunohistochemistry, and immunofluorescence were used to assess pleural injury. ELISA, cytokine array and western analyses were used to assess pleural fluid mediators and markers of MesoMT in primary PMCs., Results: Induction of empyema was done through intranasal or intrapleural delivery of S. pneumoniae. Intranasal delivery impaired lung compliance (p < 0.05) and reduced lung volume (p < 0.05) by 7 days, but failed to reliably induce empyema and was characterized by unacceptable mortality. Intrapleural delivery of S. pneumoniae induced empyema by 24 h with lung restriction and development of pleural fibrosis which persisted for up to 14 days. Markers of MesoMT were increased in the visceral pleura of S. pneumoniae infected mice. KC, IL-17A, MIP-1β, MCP-1, PGE2 and plasmin activity were increased in pleural lavage of infected mice at 7 days. PAI-1(-/-) mice died within 4 days, had increased pleural inflammation and higher PGE2 levels than WT mice. PGE2 was induced in primary PMCs by uPA and plasmin and induced markers of MesoMT., Conclusion: To our knowledge, this is the first murine model of subacute, organizing empyema. The model can be used to identify factors that, like PAI-1 deficiency, alter outcomes and dissect their contribution to pleural organization, rind formation and lung restriction.

Gram-stain-positive, partially acid-fast, non-spore-forming, anaerobic, catalase-positive, pleomorphic bacteria were isolated from human abscesses. Strains X1036T, X1698 and NML 120705, were recovered from a spinal abscess, a peritoneal abscess and a breast abscess respectively. A phylogenetic analysis of the 16S rRNA gene sequences showed that the strains shared 100 % similarity, and the nearest phylogenetic neighbour was Dietzia timorensis DSM 45568T (95%). Chemotaxonomic characteristics of the strains were consistent with those described for members of the suborder Corynebacterineae. Mycolic acids were detected using HPLC and one-dimensional TLC; whole-cell hydrolysates yielded meso-diaminopimelic acid with arabinose and galactose as the predominant sugars; the muramic acid acyl type was acetylated; the major menaquinone was MK-9 (96.3%); polar lipids detected were phosphatidylglycerol, phosphatidylinositol and an unknown glycophospholipid. Cellular fatty acids were hexadecanoic acid (C16 : 0), octadecenoic acid (C18 : 1ω9c) and decanoic acid (C10 : 0). Tuberculostearic acid was not detected. Based on the results of this polyphasic study, we conclude that these strains represent a novel genus and species within the suborder Corynebacterineae for which we propose the name Lawsonella clevelandensis gen. nov., sp. nov., with the type strain X1036T (=DSM 45743T=CCUG 66657T).

Pleural organization follows acute injury and is characterized by pleural fibrosis, which may involve the visceral and parietal pleural surfaces. This process affects patients with complicated parapneumonic pleural effusions, empyema, and other pleural diseases prone to pleural fibrosis and loculation. Pleural mesothelial cells (PMCs) undergo a process called mesothelial mesenchymal transition (MesoMT), by which PMCs acquire a profibrotic phenotype characterized by cellular enlargement and elongation, increased expression of α-smooth muscle actin (α-SMA), and matrix proteins including collagen-1. Although MesoMT contributes to pleural fibrosis and lung restriction in mice with carbon black/bleomycin-induced pleural injury and procoagulants and fibrinolytic proteases strongly induce MesoMT in vitro, the mechanism by which this transition occurs remains unclear. We found that thrombin and plasmin potently induce MesoMT in vitro as does TGF-β. Furthermore, these mediators of MesoMT activate phosphatidylinositol-3-kinase (PI3K)/Akt and NF-κB signaling pathways. Inhibition of PI3K/Akt signaling prevented TGF-β-, thrombin-, and plasmin-mediated induction of the MesoMT phenotype exhibited by primary human PMCs. Similar effects were demonstrated through blockade of the NF-κB signaling cascade using two distinctly different NF-κB inhibitors, SN50 and Bay-11 7085. Conversely, expression of constitutively active Akt-induced mesenchymal transition in human PMCs whereas the process was blocked by PX866 and AKT8. Furthermore, thrombin-mediated MesoMT is dependent on PAR-1 expression, which is linked to PI3K/Akt signaling downstream. These are the first studies to demonstrate that PI3K/Akt and/or NF-κB signaling is critical for induction of MesoMT., (Copyright © 2015 the American Physiological Society.)

Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of the extrinsic coagulation cascade, and its expression is reported to be relatively stable. Various pathophysiologic agents have been shown to influence TFPI activity by regulating its expression or by modifying the protein. It is not clear how TFPI activity is regulated in normal physiology or in injury. Because thrombin and TFPI are locally elaborated in pleural injury, we sought to determine if thrombin could regulate TFPI in human pleural mesothelial cells (HPMCs). Thrombin significantly decreased TFPI mRNA and protein levels by > 70%. Thrombin-mediated down-regulation of TFPI promoted factor X activation by HPMCs. The ability of thrombin to significantly decrease TFPI mRNA and protein levels was maintained at nanomolar concentrations. Protease-activated receptor (PAR)-1, a mediator of thrombin signaling, is detectable in the mesothelium in human and murine pleural injury. PAR-1 silencing blocked thrombin-mediated decrements of TFPI in HPMCs. Thrombin activates PI3K/Akt and nuclear factor κB (NF-κB) signaling in HPMCs. Inhibition of PI3K (by PX-866) and NF-κB (by SN50) prevented thrombin-mediated TFPI mRNA and protein down-regulation. These are the first studies to demonstrate that thrombin decreases TFPI expression in HPMCs. Our findings demonstrate a novel mechanism by which thrombin regulates TFPI expression in HPMCs and promotes an unrestricted procoagulant response, and suggest that interactions between PI3K and NF-κB signaling pathways are linked in HPMCs and control TFPI expression. These findings raise the possibility that targeting this pathway could limit the ability of the mesothelium to support extravascular fibrin deposition and organization associated with pleural injury.

Background: The recently-identified causative agent of White-Nose Syndrome (WNS), Pseudogymnoascus destructans, has been responsible for the mortality of an estimated 5.5 million North American bats since its emergence in 2006. A primary focus of the National Response Plan, established by multiple state, federal and tribal agencies in 2011, was the identification of biological control options for WNS. In an effort to identify potential biological control options for WNS, multiply induced cells of Rhodococcus rhodochrous strain DAP96253 was screened for anti-P. destructans activity., Results: Conidia and mycelial plugs of P. destructans were exposed to induced R. rhodochrous in a closed air-space at 15°C, 7°C and 4°C and were evaluated for contact-independent inhibition of conidia germination and mycelial extension with positive results. Additionally, in situ application methods for induced R. rhodochrous, such as fixed-cell catalyst and fermentation cell-paste in non-growth conditions, were screened with positive results. R. rhodochrous was assayed for ex vivo activity via exposure to bat tissue explants inoculated with P. destructans conidia. Induced R. rhodochrous completely inhibited growth from conidia at 15°C and had a strong fungistatic effect at 4°C. Induced R. rhodochrous inhibited P. destructans growth from conidia when cultured in a shared air-space with bat tissue explants inoculated with P. destructans conidia., Conclusion: The identification of inducible biological agents with contact-independent anti- P. destructans activity is a major milestone in the development of viable biological control options for in situ application and provides the first example of contact-independent antagonism of this devastating wildlife pathogen.

Local derangements of fibrin turnover and plasminogen activator inhibitor (PAI)-1 have been implicated in the pathogenesis of pleural injury. However, their role in the control of pleural organization has been unclear. We found that a C57Bl/6j mouse model of carbon black/bleomycin (CBB) injury demonstrates pleural organization resulting in pleural rind formation (14 d). In transgenic mice overexpressing human PAI-1, intrapleural fibrin deposition was increased, but visceral pleural thickness, lung volumes, and compliance were comparable to wild type. CBB injury in PAI-1(-/-) mice significantly increased visceral pleural thickness (P < 0.001), elastance (P < 0.05), and total lung resistance (P < 0.05), while decreasing lung compliance (P < 0.01) and lung volumes (P < 0.05). Collagen, α-smooth muscle actin, and tissue factor were increased in the thickened visceral pleura of PAI-1(-/-) mice. Colocalization of α-smooth muscle actin and calretinin within pleural mesothelial cells was increased in CBB-injured PAI-1(-/-) mice. Thrombin, factor Xa, plasmin, and urokinase induced mesothelial-mesenchymal transition, tissue factor expression, and activity in primary human pleural mesothelial cells. In PAI-1(-/-) mice, D-dimer and thrombin-antithrombin complex concentrations were increased in pleural lavage fluids. The results demonstrate that PAI-1 regulates CBB-induced pleural injury severity via unrestricted fibrinolysis and cross-talk with coagulation proteases. Whereas overexpression of PAI-1 augments intrapleural fibrin deposition, PAI-1 deficiency promotes profibrogenic alterations of the mesothelium that exacerbate pleural organization and lung restriction.

The procoagulant protein tissue factor (F3) is a powerful growth promoter in many tumors, but its mechanism of action is not well understood. More generally, it is unknown whether hemostatic factors expressed on tumor cells influence tissue factor-mediated effects on cancer progression. In this study, we investigated the influence of tissue factor, endothelial cell protein C receptor (EPCR, PROCR), and protease activated receptor-1 (PAR1, F2R) on the growth of malignant pleural mesothelioma (MPM), using human MPM cells that lack or express tissue factor, EPCR or PAR1, and an orthotopic nude mouse model of MPM. Intrapleural administration of MPM cells expressing tissue factor and PAR1 but lacking EPCR and PAR2 (F2RL1) generated large tumors in the pleural cavity. Suppression of tissue factor or PAR1 expression in these cells markedly reduced tumor growth. In contrast, tissue factor overexpression in nonaggressive MPM cells that expressed EPCR and PAR1 with minimal levels of tissue factor did not increase their limited tumorigenicity. More importantly, ectopic expression of EPCR in aggressive MPM cells attenuated their growth potential, whereas EPCR silencing in nonaggressive MPM cells engineered to overexpress tissue factor increased their tumorigenicity. Immunohistochemical analyses revealed that EPCR expression in tumor cells reduced tumor cell proliferation and enhanced apoptosis. Overall, our results enlighten the mechanism by which tissue factor promotes tumor growth through PAR1, and they show how EPCR can attenuate the growth of tissue factor-expressing tumor cells., (©2013 AACR.)

Elevated concentrations of plasminogen activator inhibitor-1 (PAI-1) are associated with pleural injury, but its effects on pleural organization remain unclear. A method of adenovirus-mediated delivery of genes of interest (expressed under a cytomegalovirus promoter) to rabbit pleura was developed and used with lacZ and human (h) PAI-1. Histology, β-galactosidase staining, Western blotting, enzymatic and immunohistochemical analyses of pleural fluids (PFs), lavages, and pleural mesothelial cells were used to evaluate the efficiency and effects of transduction. Transduction was selective and limited to the pleural mesothelial monolayer. The intrapleural expression of both genes was transient, with their peak expression at 4 to 5 days. On Day 5, hPAI-1 (40-80 and 200-400 nM of active and total hPAI-1 in lavages, respectively) caused no overt pleural injury, effusions, or fibrosis. The adenovirus-mediated delivery of hPAI-1 with subsequent tetracycline-induced pleural injury resulted in a significant exacerbation of the pleural fibrosis observed on Day 5 (P = 0.029 and P = 0.021 versus vehicle and adenoviral control samples, respectively). Intrapleural fibrinolytic therapy (IPFT) with plasminogen activators was effective in both animals overexpressing hPAI-1 and control animals with tetracycline injury alone. An increase in intrapleural active PAI-1 (from 10-15 nM in control animals to 20-40 nM in hPAI-1-overexpressing animals) resulted in the increased formation of PAI-1/plasminogen activator complexes in vivo. The decrease in intrapleural plasminogen-activating activity observed at 10 to 40 minutes after IPFT correlates linearly with the initial concentration of active PAI-1. Therefore, active PAI-1 in PFs affects the outcome of IPFT, and may be both a biomarker of pleural injury and a molecular target for its treatment.

Rhodococcus is an important industrial microorganism that possesses diverse metabolic capabilities; it also has a cell envelope, composed of an outer layer of mycolic acids and glycolipids. Selected Rhodococcus species when induced are capable of transforming nitriles to the corresponding amide by the enzyme nitrile hydratase (NHase), and subsequently to the corresponding acid via an amidase. This nitrile biochemistry has generated interest in using the rhodococci as biocatalysts. It was hypothesized that altering sugars in the growth medium might impact cell envelope components and have effects on NHase. When the primary carbon source in growth media was changed from glucose to fructose, maltose, or maltodextrin, the NHase activity increased. Cells grown in the presence of maltose and maltodextrin showed the highest activities against propionitrile, 197 and 202 units/mg cdw, respectively. Stability of NHase was also affected as cells grown in the presence of maltose and maltodextrin retained more NHase activity at 55 °C (45 and 23 %, respectively) than cells grown in the presence of glucose or fructose (19 and 10 %, respectively). Supplementation of trehalose in the growth media resulted in increased NHase stability at 55 °C, as cells grown in the presence of glucose retained 40 % NHase activity as opposed to 19 % without the presence of trehalose. Changes in cell envelope components, such mycolic acids and glycolipids, were evaluated by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC), respectively. Changing sugars and the addition of inducing components for NHase, such as cobalt and urea in growth media, resulted in changes in mycolic acid profiles. Mycolic acid content increased 5 times when cobalt and urea were added to media with glucose. Glycolipids levels were also affected by the changes in sugars and addition of inducing components. This research demonstrates that carbohydrate selection impacts NHase activity and stability. Cell envelope components such as mycolic acids are also influenced by sugars and inducers such as cobalt and urea. This is information that can be useful when implementing rhodococcal catalysts in industrial applications.

Background: Rescue or correction of CFTR function in native epithelia is the ultimate goal of CF therapeutics development. Wild-type (WT) CFTR introduction and replacement is also of particular interest. Such therapies may be complicated by possible CFTR self-assembly into an oligomer or multimer., Results: Surprisingly, functional CFTR assays in native airway epithelia showed that the most common CFTR mutant, ΔF508-CFTR (ΔF-CFTR), inhibits WT-CFTR when both forms are co-expressed. To examine more mechanistically, both forms of CFTR were transfected transiently in varying amounts into IB3-1 CF human airway epithelial cells and HEK-293 human embryonic kidney cells null for endogenous CFTR protein expression. Increasing amounts of ΔF-CFTR inhibited WT-CFTR protein processing and function in CF human airway epithelial cells but not in heterologous HEK-293 cells. Stably expressed ΔF-CFTR in clones of the non-CF human airway epithelial cell line, CALU-3, also showed reduction in cAMP-stimulated anion secretion and in WT-CFTR processing. An ultimate test of this dominant negative-like effect of ΔF-CFTR on WT-CFTR was the parallel study of two different CF mouse models: the ΔF-CFTR mouse and the bitransgenic CFTR mouse corrected in the gut but null in the lung and airways. WT/ΔF heterozygotes had an intermediate phenotype with regard to CFTR agonist responses in in vivo nasal potential difference (NPD) recordings and in Ussing chamber recordings of short-circuit current (ISC) in vitro on primary tracheal epithelial cells isolated from the same mice. In contrast, CFTR bitransgenic +/- heterozygotes had no difference in their responses versus +/+ wild-type mice., Conclusions: Taken altogether, these data suggest that ΔF-CFTR and WT-CFTR co-assemble into an oligomeric macromolecular complex in native epithelia and share protein processing machinery and regulation at the level of the endoplasmic reticulum (ER). As a consequence, ΔF-CFTR slows WT-CFTR protein processing and limits its expression and function in the apical membrane of native airway epithelia. Implications of these data for the relative health of CF heterozygous carriers, for CFTR protein processing in native airway epithelia, and for the relative efficacy of different CF therapeutic approaches is significant and is discussed.

The low-density lipoprotein receptor-related protein 1 (LRP-1) binds and can internalize a diverse group of ligands, including members of the fibrinolytic pathway, urokinase plasminogen activator (uPA), and its receptor, uPAR. In this study, we characterized the role of LRP-1 in uPAR processing, collagen synthesis, proteolysis, and migration in pleural mesothelial cells (PMCs). When PMCs were treated with the proinflammatory cytokines TNF-α and IL-1β, LRP-1 significantly decreased at the mRNA and protein levels (70 and 90%, respectively; P < 0.05). Consequently, uPA-mediated uPAR internalization was reduced by 80% in the presence of TNF-α or IL-1β (P < 0.05). In parallel studies, LRP-1 neutralization with receptor-associated protein (RAP) significantly reduced uPA-dependent uPAR internalization and increased uPAR stability in PMCs. LRP-1-deficient cells demonstrated increased uPAR t(1/2) versus LRP-1-expressing PMCs. uPA enzymatic activity was also increased in LRP-1-deficient and neutralized cells, and RAP potentiated uPA-dependent migration in PMCs. Collagen expression in PMCs was also induced by uPA, and the effect was potentiated in RAP-treated cells. These studies indicate that TNF-α and IL-1β regulate LRP-1 in PMCs and that LRP-1 thereby contributes to a range of pathophysiologically relevant responses of these cells.

Malignant pleural mesothelioma (MPM) is a rare cancer that is refractory to current treatments. It is characterized by a robust deposition of transitional fibrin that is in part promoted by tumor cells. MPM cells express tissue factor (TF) and the tissue factor pathway inhibitor (TFPI), but their contribution to the pathogenesis of MPM has been unclear. We found that REN MPM cells fail to express TFPI. Based on the tumor growth-promoting properties of TF, we hypothesized that the stable transfection of TFPI into REN MPM cells would decrease their aggressiveness. We tested our hypothesis using in vitro, in vivo, and ex vivo analyses. TFPI knock-in decreased the proliferation, invasion, and TF activity of REN cells in vitro. REN TFPI knock-in cells, empty vector, and naive control cells were next injected intrapleurally into nude mice. The expression of TFPI significantly decreased tissue invasion, inflammation, and the deposition of fibrin and collagen associated with tumor tissue, pleural effusions, and tumor burden. In ex vivo analyses, REN cells were cultured from harvested tumors. The overexpression of TFPI was maintained in cells propagated from TFPI knock-in tumors, and attenuated the activation of Factor X and the invasiveness of tumor cells. These analyses demonstrate that TFPI reduces the aggressiveness of MPM in vitro and in vivo, and that its effect involves the inhibition of TF procoagulant activity. These observations suggest that the interactions of TF and TFPI represent a novel therapeutic target in the treatment of MPM.

Despite the use of refrigeration, improved packaging, adsorbents, and ethylene receptor blockers, on average, nearly 40% of all fruits and vegetables harvested in the US are not consumed. Many plant products, especially fruit, continue to ripen after harvesting, and as they do so, become increasingly susceptible to mechanical injury, resulting in increased rot. Other plant products during transportation and storage are susceptible to chill injury (CI). There is a real need for products that can delay ripening or mitigate the effects of CI, yet still permit full ripeness and quality to be achieved. Preliminary results are discussed where catalyst derived from cells of Rhodococcus rhodochrous DAP 96253, grown under conditions that induced high levels of nitrile hydratase, were able to extend the ripening and thus the shelf-life of selected climacteric fruits (banana, avocado, and peach). A catalyst, when placed in proximity to, but not touching, the test fruit delayed the ripening but did not alter the final ripeness of the fruit tested. Organoleptic evaluations conducted with control peaches and with peaches exposed to, but not in contact with, the catalyst showed that the catalyst-treated peaches achieved full, natural levels of ripeness with respect to aroma, flavor, sweetness, and juice content. Furthermore, the results of delayed ripening were achieved at ambient temperatures (without the need for refrigeration).