In the Shadow of Fibrosis: Innate Immune Suppression Mediated by Transforming Growth Factor-β

Losartan alters osteoblast differentiation and increases bone mass through inhibition of TGFB signalling in vitro and in an OIM mouse model

Excessive production of Transforming Growth Factor β (TGFβ) is commonly associated with dominant and recessive forms of OI. Previous reports have indicated that administration of TGFβ-targeted antibodies maybe of potential therapeutic benefit to OI patients. However, direct targeting of TGFβ is likely to cause multiple adverse effects including simulation of autoimmunity. In the current study we use patient-derived normal and OI fibroblasts, osteoblasts and OIM mouse models to determine the effects of Losartan, an angiotensin II receptor type 1 (AT1) antagonist, on TGFβ signalling and bone morphology in OI. In OIM mice bred on a mixed background administration of 0.6 g/L losartan for 4 weeks was associated with a significant reduction in TGFβ from 79.2 g/L in the control to 60.0 ng/ml following losartan (p < 0.05), reduced osteoclast activity as measured by CTX from 275.9 ng/ml in the control to 157.2 ng/ml following 0.6 g/L of losartan (p < 0.05) and increased cortical bone thickness (P < 0.001). Furthermore in OIM mice bred on a C57BL/6 background 0.6 g/L losartan increased trabecular bone volume in the tibiae (P < 0.05) and the vertebrae (P < 0.01), increased cortical bone thickness (P < 0.001) reduced the trabecular pattern factor (P < 0.01 and P < 0.001 for the tibiae and vertebrae respectively), reduced osteoclast (P < 0.05) and osteoblast (P < 0.01) numbers as well as reducing the area of bone covered by these cell types. Interestingly, losartan did not affect immune cells infiltrating into bone, nor did this drug alter TGFβ signalling in normal or OI fibroblasts. Instead, losartan reduced SMAD2 phosphorylation in osteoblasts, inhibiting their ability to differentiate. Our data suggest that losartan may be an effective treatment for the bone-associated dysmorphia displayed in OI whilst minimising potential adverse immune cell-related effects.

Evolving Paradigms in Sepsis Management: A Narrative Review

Sepsis, a condition characterized by life-threatening organ dysfunction due to a dysregulated host response to infection, significantly impacts global health, with mortality rates varying widely across regions. Traditional therapeutic strategies that target hyperinflammation and immunosuppression have largely failed to improve outcomes, underscoring the need for innovative approaches. This review examines the development of therapeutic agents for sepsis, with a focus on clinical trials addressing hyperinflammation and immunosuppression. It highlights the frequent failures of these trials, explores the underlying reasons, and outlines current research efforts aimed at bridging the gap between theoretical advancements and clinical applications. Although personalized medicine and phenotypic categorization present promising directions, this review emphasizes the importance of understanding the complex pathogenesis of sepsis and developing targeted, effective therapies to enhance patient outcomes. By addressing the multifaceted nature of sepsis, future research can pave the way for more precise and individualized treatment strategies, ultimately improving the management and prognosis of sepsis patients.

Full-spectrum cannabidiol reduces UVB damage through the inhibition of TGF-β1 and the NLRP3 inflammasome

The thermodynamic characteristics, antioxidant potential, and photoprotective benefits of full-spectrum cannabidiol (FS-CBD) against UVB-induced cellular death were examined in this study. In silico analysis of CBD showed antioxidant capacity via proton donation and UV absorption at 209.09, 254.73, and 276.95 nm, according to the HAT and SPLET methodologies. FS-CBD protected against UVB-induced bacterial death for 30 min. FS-CBD protected against UVB-induced cell death by 42% (1.5 μg/mL) and 35% (3.5 μg/mL) in an in vitro keratinocyte cell model. An in vivo acute irradiated CD-1et/et mouse model (UVB-irradiated for 5 min) presented very low photoprotection when FS-CBD was applied cutaneously, as determined by histological analyses. In vivo skin samples showed that FS-CBD regulated inflammatory responses by inhibiting the inflammatory markers TGF-β1 and NLRP3. The docking analysis showed that the CBD molecule had a high affinity for TGF-β1 and NLRP3, indicating that protection against inflammation might be mediated by blocking these proinflammatory molecules. This result was corroborated by the docking interactions between CBD and TGF-β1 and NLRP3, which resulted in a high affinity and inhibition of both proteins The present work suggested a FS-CBD moderate photoprotective agent against UVB light-induced skin damage and that this effect is partially mediated by its anti-inflammatory activity.

Vascularized fascial flap for reconstruction of combined oral mucosa-mandibular defects: The multi-modal biological assessment

OBJECTIVE

The reconstruction of composite defects in the oral and maxillofacial region using vascularized fascial flaps, such as the fibular, iliac, and temporal fascial flaps, has gained increasing attention among surgeons. However, there remains uncertainty regarding the suitability of fascial flaps as transplants, as well as their healing processes and outcomes, due to their non-mucosal nature. This study aims to comprehensively assess the biological aspects of vascularized fascial flaps at clinical, histological, and genetic levels, with the goal of providing essential biological references for their clinical application.

STUDY DESIGN

This study enrolled three patients who underwent reconstruction of combined oral mucosa-mandibular defects using fibular vascularized fascial flaps between 2020 and 2023. Data regarding changes in the appearance of the fascial flaps, bulk-RNA sequencing, and histological slices of initial fascia, initial gingiva, and transformed fascia were collected and analyzed.

RESULTS

Within three months, the fascial flaps exhibited rapid epithelial coverage and displayed distinct characteristics resembling mucosa. High-throughput RNA sequencing analyses and histological slices revealed that the transformed fascia exhibited tissue structures similar to mucosa and demonstrated unique advantages in promoting blood vessel formation and reducing scarring through the high-level expression of relevant genes.

CONCLUSION

These findings emphasize the potential and feasibility of utilizing vascularized fascial flaps for oral mucosa reconstruction, establishing their unique advantage as transplant materials, and providing significant biological information and references for their selection and clinical application.

Polyubiquitylated rice stripe virus NS3 translocates to the nucleus to promote cytosolic virus replication via miRNA-induced fibrillin 2 upregulation

Viruses are encapsidated mobile genetic elements that rely on host cells for replication. Several cytoplasmic RNA viruses synthesize proteins and/or RNAs that translocate to infected cell nuclei. However, the underlying mechanisms and role(s) of cytoplasmic-nuclear trafficking are unclear. We demonstrate that infection of small brown planthoppers with rice stripe virus (RSV), a negarnaviricot RNA virus, results in K63-linked polyubiquitylation of RSV's nonstructural protein 3 (NS3) at residue K127 by the RING ubiquitin ligase (E3) LsRING. In turn, ubiquitylation leads to NS3 trafficking from the cytoplasm to the nucleus, where NS3 regulates primary miRNA pri-miR-92 processing through manipulation of the microprocessor complex, resulting in accumulation of upregulated miRNA lst-miR-92. We show that lst-miR-92 regulates the expression of fibrillin 2, an extracellular matrix protein, thereby increasing RSV loads. Our results highlight the manipulation of intranuclear, cytoplasmic, and extracellular components by an RNA virus to promote its own replication in an insect vector.

Differential expression of Type I interferon and inflammatory genes in SARS-CoV-2-infected patients treated with monoclonal antibodies

INTRODUCTION

Considering the reported efficacy of monoclonal antibodies (mAbs) directed against the Spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in reducing disease severity, the aim of this study was to investigate the innate immune response before and after mAbs treatment in 72 vaccinated and 31 unvaccinated SARS-CoV-2 patients.

METHODS

The mRNA levels of IFN-I, IFN-related genes and cytokines were evaluated using RT/real-time quantitative PCR.

RESULTS

Vaccinated patients showed increased rate of negative SARS-CoV-2 PCR tests on nasopharyngeal swab compared with unvaccinated ones after mAbs treatment (p = .002). Unvaccinated patients had lower IFN-α/ω and higher IFN-related genes (IFNAR1, IFNAR2, IRF9, ISG15, ISG56 and IFI27) and cytokines (IL-6, IL-10 and TGF-β) mRNA levels compared to vaccinated individuals before mAbs (p < .05 for all genes). Increased IFN-α/ω, IFNAR1, IFNAR2 and IRF9 levels were observed in unvaccinated patients after mAbs treatment, while the mRNA expression ISGs and IL-10 were reduced in all patients.

CONCLUSION

These data suggest that anti-S vaccinated patients have increased levels of innate immune genes compared to unvaccinated ones. Also, gene expression changes in IFN genes after mAbs administration are different according to the vaccination status of patients.

Furin as a therapeutic target in cystic fibrosis airways disease

Clinical management of cystic fibrosis (CF) has been greatly improved by the development of small molecule modulators of the CF transmembrane conductance regulator (CFTR). These drugs help to address some of the basic genetic defects of CFTR; however, no suitable CFTR modulators exist for 10% of people with CF (PWCF). An alternative, mutation-agnostic therapeutic approach is therefore still required. In CF airways, elevated levels of the proprotein convertase furin contribute to the dysregulation of key processes that drive disease pathogenesis. Furin plays a critical role in the proteolytic activation of the epithelial sodium channel; hyperactivity of which causes airways dehydration and loss of effective mucociliary clearance. Furin is also responsible for the processing of transforming growth factor-β, which is increased in bronchoalveolar lavage fluid from PWCF and is associated with neutrophilic inflammation and reduced pulmonary function. Pathogenic substrates of furin include Pseudomonas exotoxin A, a major toxic product associated with Pseudomonas aeruginosa infection and the spike glycoprotein of severe acute respiratory syndrome coronavirus 2, the causative pathogen for coronavirus disease 2019. In this review we discuss the importance of furin substrates in the progression of CF airways disease and highlight selective furin inhibition as a therapeutic strategy to provide clinical benefit to all PWCF.

USP33 promotes pancreatic cancer malignant phenotype through the regulation of TGFBR2/TGFβ signaling pathway

Pancreatic cancer (PC) ranked fourth among cancer-related death worldwide with a survival rate less than 5%. The abnormal proliferation and distant metastasis are major obstacles for the diagnosis and treatment of pancreatic cancer, therefore, it is urgent for researchers to uncover the molecular mechanisms underlying the PC proliferation and metastasis. In current study, we found that USP33, a member of deubiquitinating enzyme family, was upregulated among PC samples and cells, meanwhile, the high expression of USP33 correlated with poor prognosis of patients. Function experiments revealed that USP33 overexpression promoted the proliferation, migration and invasion of PC cells while the inhibition of USP33 expression in PC cells exhibited the opposite effect. The mass spectrum and luciferase complementation assay screened TGFBR2 as the potential binding protein of USP33. Mechanistically, USP33 triggered the deubiquitination of TGFBR2 and prevented its degradation by lysosome, therefore promoted TGFBR2 accumulation in cell membrane and eventually contributed to the sustained activation of TGF-β signaling. Moreover, our results revealed that the activation of TGF-β targeted gene ZEB1 promoted the transcription of USP33. In conclusion, our study found that USP33 contributed to the proliferation and metastasis of pancreatic cancer through a positive feedback loop with TGF-β signaling pathway. Moreover, this study suggested that USP33 may serve as a potential prognostic and therapeutic target in PC.

Inflammation-Associated Lung Tissue Remodeling and Fibrosis in Morphine-Dependent SIV-Infected Macaques

With the advent of antiretroviral therapy, improved survival of people with HIV (PWH) is accompanied with increased prevalence of HIV-associated comorbidities. Chronic lung anomalies are recognized as one of the most devastating sequelae in PWH. The limited available data describing the lung complications in PWH with a history of opioid abuse warrants more research to better define the course of disease pathogenesis. The current study was conducted to investigate the progression of lung tissue remodeling in a morphine (Mor)-exposed rhesus macaque model of SIV infection. Pathologic features of lung remodeling, including histopathologic changes, oxidative stress, inflammation, and proliferation of fibroblasts, were investigated in archival lung tissues of SIVmac-251/macaque model with or without Mor dependence. Lungs of Mor-exposed, SIV-infected macaques exhibited significant fibrotic changes and collagen deposition in the alveolar and the bronchiolar region. There was increased oxidative stress, profibrotic transforming growth factor-β, fibroblast proliferation and trans-differentiation, epithelial-mesenchymal transition, and matrix degradation in SIV-infected macaques, which was further exacerbated in the lungs of Mor-exposed macaques. Interestingly, there was decreased inflammation-associated remodeling in Mor-dependent SIV-infected macaques compared with SIV-infected macaques that did not receive Mor. Thus, the current findings suggest that SIV independently induces fibrotic changes in macaque lungs, which is further aggravated by Mor.

Monitoring of the Forgotten Immune System during Critical Illness-A Narrative Review

Immune organ failure is frequent in critical illness independent of its cause and has been acknowledged for a long time. Most patients admitted to the ICU, whether featuring infection, trauma, or other tissue injury, have high levels of alarmins expression in tissues or systemically which then activate innate and adaptive responses. Although necessary, this response is frequently maladaptive and leads to organ dysfunction. In addition, the counter-response aiming to restore homeostasis and repair injury can also be detrimental and contribute to persistent chronic illness. Despite intensive research on this topic in the last 40 years, the immune system is not routinely monitored in critical care units. In this narrative review we will first discuss the inflammatory response after acute illness and the players of maladaptive response, focusing on neutrophils, monocytes, and T cells. We will then go through commonly used biomarkers, like C-reactive protein, procalcitonin and pancreatic stone protein (PSP) and what they monitor. Next, we will discuss the strengths and limitations of flow cytometry and related techniques as an essential tool for more in-depth immune monitoring and end with a presentation of the most promising cell associated markers, namely HLA-DR expression on monocytes, neutrophil expression of CD64 and PD-1 expression on T cells. In sum, immune monitoring critically ill patients is a forgotten and missing piece in the monitoring capacity of intensive care units. New technology, including bed-side equipment and in deep cell phenotyping using emerging multiplexing techniques will likely allow the definition of endotypes and a more personalized care in the future.

Research Note: Transcriptomic analysis of LMH cells in response to the overexpression of a hypothetical protein identified in Eimeria tenella SD-01 strain

Though genome sequencing of Eimeria tenella predicts more than 8,000 genes, the molecular functions of many proteins remain unknown. In this study, the coding region corresponding to the mature peptide of a hypothetical protein of E. tenella (ETH_00023950) was amplified and expressed in a bacterial system. Following preparation of polyclonal antibody that recognizes ETH_00023950, the expression of ETH_00023950 in merozoites was examined. Meanwhile, we determined the transcriptomic responses of the leghorn male hepatoma (LMH) cells to its expression. Sequencing analysis showed that one single nucleotide polymorphism and one indel of ETH_00023950 of E. tenella SD-01 strain were found compared with that of the UK reference Houghton strain, leading to a frame shift and a premature stop codon. The expression of ETH_00023950 in E. tenella merozoites was confirmed by indirect immunofluorescence and Western blot analysis. Transcriptomic analysis showed that ETH_00023950 altered the expression of 2,680 genes (321 downregulated genes and 2,359 upregulated genes) in LMH cells. The RNA-sequencing data were consistent with the results of the quantitative real-time polymerase chain reaction (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that differentially expressed transcripts were significantly related to 8 pathways, including oxidative phosphorylation and TGF-beta signaling pathway. These findings contribute to understanding host-pathogen interaction and secondary bacterial infections related to E. tenella.

Regulatory T Cells Decreased during Recovery from Mild COVID-19

Depending on the intensity and duration of SARS-CoV-2 infection, the host immune response plays a significant role in immunological protection. Here, we studied the regulatory T-cell (Treg) response in relation to kinetic change and cytokine production in patients with mild COVID-19. Nineteen SARS-CoV-2-positive patients were recruited, and blood was collected at four time points, i.e., seven days after admission, after discharge, and one and three months after recovery. CD3⁺CD4⁺CD25⁺CD127^low was marked as the Treg population, with IL-10 and TGF-β used to study cytokine-producing Tregs. IFN-γ-producing CD8⁺ T cells were observed for an effector response. The Treg percentage in patients with mild COVID-19 increased during hospitalization compared to during the recovery period. Peripheral blood mononuclear cells (PBMCs) were quantified, and the T-cell response was characterized by re-stimulation with S1 and N peptides. IL-10 and TGF-β were produced by CD25⁺CD127^low T cells during the active infection phase, especially with N peptide stimulation. Compared to N peptide stimulation, S1 peptide stimulation provided superior IFN-γ-secreting CD8⁺ T-cell responses. Our results suggest that while IFN-γ⁺CD8⁺ T cells confer antiviral immunity, cytokine-producing Tregs may have a substantial role in regulating inflammatory responses in mild SARS-CoV-2 infection. Novel vaccine development may also consider enhancing T-cell repertoires.

Single-cell transcriptomics reveals immune dysregulation mediated by IL-17A in initiation of chronic lung injuries upon real-ambient particulate matter exposure

Background

Long-term exposure to fine particulate matter (PM_2.5) increases susceptibility to chronic respiratory diseases, including inflammation and interstitial fibrosis. However, the regulatory mechanisms by which the immune response mediates the initiation of pulmonary fibrosis has yet to be fully characterized. This study aimed to illustrate the interplay between different cell clusters and key pathways in triggering chronic lung injuries in mice following PM exposure.

Results

Six-week-old C57BL/6J male mice were exposed to PM or filtered air for 16 weeks in a real-ambient PM exposure system in Shijiazhuang, China. The transcriptional profiles of whole lung cells following sub-chronic PM exposure were characterized by analysis of single-cell transcriptomics. The IL-17A knockout (IL-17A^−/−) mouse model was utilized to determine whether the IL-17 signaling pathway mediated immune dysregulation in PM-induced chronic lung injuries. After 16-week PM exposure, chronic lung injuries with excessive collagen deposition and increased fibroblasts, neutrophils, and monocytes were noted concurrent with a decreased number of major classes of immune cells. Single-cell analysis showed that activation of the IL-17 signaling pathway was involved in the progression of pulmonary fibrosis upon sub-chronic PM exposure. Depletion of IL-17A led to significant decline in chronic lung injuries, which was mainly triggered by reduced recruitment of myeloid-derived suppressor cells (MDSCs) and downregulation of TGF-β.

Conclusion

These novel findings demonstrate that immunosuppression via the IL-17A pathway plays a critical role in the initiation of chronic lung injuries upon sub-chronic PM exposure.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00483-w.

Possible Role of Matrix Metalloproteinases and TGF-β in COVID-19 Severity and Sequelae

The costs of coronavirus disease 2019 (COVID-19) are devastating. With millions of deaths worldwide, specific serological biomarkers, antiviral agents, and novel therapies are urgently required to reduce the disease burden. For these purposes, a profound understanding of the pathobiology of COVID-19 is mandatory. Notably, the study of immunity against other respiratory infections has generated reference knowledge to comprehend the paradox of the COVID-19 pathogenesis. Past studies point to a complex interplay between cytokines and other factors mediating wound healing and extracellular matrix (ECM) remodeling that results in exacerbated inflammation, tissue injury, severe manifestations, and a sequela of respiratory infections. This review provides an overview of the immunological process elicited after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Also, we analyzed available data about the participation of matrix metalloproteinases (MMPs) and transforming growth factor-beta (TGF-β) in immune responses of the lungs. Furthermore, we discuss their possible implications in severe COVID-19 and sequela, including pulmonary fibrosis, and remark on the potential of these molecules as biomarkers for diagnosis, prognosis, and treatment of convalescent COVID-19 patients. Our review provides a theoretical framework for future research aimed to discover molecular hallmarks that, combined with clinical features, could serve as therapeutic targets and reliable biomarkers of the different clinical forms of COVID-19, including convalescence.

Screening of candidate genes associated with high titer production of oncolytic measles virus based on systems biology approach

The number of viral particles required for oncolytic activity of measles virus (MV) can be more than a million times greater than the reported amount for vaccination. The aim of the current study is to find potential genes and signaling pathways that may be involved in the high-titer production of MV. In this study, a systems biology approach was considered including collection of gene expression profiles from the Gene Expression Omnibus (GEO) database, obtaining differentially expressed genes (DEGs), performing gene ontology, functional enrichment analyses, and topological analyses on the protein-protein interaction (PPI) network. Then, to validate the in-silico data, total RNA was isolated from five cell lines, and full-length cDNA from template RNA was synthesized. Subsequently, quantitative reverse transcription-PCR (RT-qPCR) was employed. We identified five hub genes, including RAC1, HSP90AA1, DNM1, LTBP1, and FSTL1 associated with the enhancement in MV titer. Pathway analysis indicated enrichment in PI3K-Akt signaling pathway, axon guidance, proteoglycans in cancer, regulation of actin cytoskeleton, focal adhesion, and calcium signaling pathways. Upon verification by RT-qPCR, the relative expression of candidate genes was generally consistent with our bioinformatics analysis. Hub genes and signaling pathways may be involved in understanding the pathological mechanisms by which measles virus manipulates host factors in order to facilitate its replication. RAC1, HSP90AA1, DNM1, LTBP1, and FSTL1 genes, in combination with genetic engineering techniques, will allow the direct design of high-throughput cell lines to answer the required amounts for the oncolytic activity of MV.

Urine-derived exosomes from individuals with IPF carry pro-fibrotic cargo

BACKGROUND

MicroRNAs (miRNA) and other components contained in extracellular vesicles may reflect the presence of a disease. Lung tissue, sputum, and sera of individuals with idiopathic pulmonary fibrosis (IPF) show alterations in miRNA expression. We designed this study to test whether urine and/or tissue derived exosomal miRNAs from individuals with IPF carry cargo that can promote fibrosis.

METHODS

Exosomes were isolated from urine (U-IPFexo), lung tissue myofibroblasts (MF-IPFexo), serum from individuals with IPF (n=16) and age/sex-matched controls without lung disease (n=10). We analyzed microRNA expression of isolated exosomes and their in vivo bio-distribution. We investigated the effect on ex vivo skin wound healing and in in vivo mouse lung models.

RESULTS

U-IPFexo or MF-IPFexo expressed miR-let-7d, miR-29a-5p, miR-181b-3p and miR-199a-3p consistent with previous reports of miRNA expression obtained from lung tissue/sera from patients with IPF. In vivo bio-distribution experiments detected bioluminescent exosomes in the lung of normal C57Bl6 mice within 5 min after intravenous infusion, followed by distribution to other organs irrespective of exosome source. Exosomes labeled with gold nanoparticles and imaged by transmission electron microscopy were visualized in alveolar epithelial type I and type II cells. Treatment of human and mouse lung punches obtained from control, non-fibrotic lungs with either U-IPFexo or MF-IPFexo produced a fibrotic phenotype. A fibrotic phenotype was also induced in a human ex vivo skin model and in in vivo lung models.

CONCLUSIONS

Our results provide evidence of a systemic feature of IPF whereby exosomes contain pro-fibrotic miRNAs when obtained from a fibrotic source and interfere with response to tissue injury as measured in skin and lung models.

FUNDING

This work was supported in part by Lester and Sue Smith Foundation and The Samrick Family Foundation and NIH grants R21 AG060338 (SE and MKG), U01 DK119085 (IP, RS, MTC).

Uterine Fibroids: Hiding in Plain Sight

Uterine fibroids (leiomyomas) are present in >75% of women and can cause serious morbidity. They are by far the leading cause of hysterectomy. Fibroids are a complex mixture of cells that include fibroblasts and smooth muscle cells. Rich in extracellular matrix, they typically arise through somatic mutations, most commonly MED12. Their lack of growth inhibition and their ability to have facets of malignancy yet be histologically and biologically benign provide opportunities to explore basic processes. To date, the mechanisms responsible for growth and development of leiomyomas are an enigma. This review provides an overview of current understanding and future directions for clinical and basic research of fibroids.

RGD-binding integrins and TGF-β in SARS-CoV-2 infections - novel targets to treat COVID-19 patients?

The new coronavirus SARS-CoV-2 is a global pandemic and a severe public health crisis. SARS-CoV-2 is highly contagious and shows high mortality rates, especially in elderly and patients with pre-existing medical conditions. At the current stage, no effective drugs are available to treat these patients. In this review, we analyse the rationale of targeting RGD-binding integrins to potentially inhibit viral cell infection and to block TGF-β activation, which is involved in the severity of several human pathologies, including the complications of severe COVID-19 cases. Furthermore, we demonstrate the correlation between ACE2 and TGF-β expression and the possible consequences for severe COVID-19 infections. Finally, we list approved drugs or drugs in clinical trials for other diseases that also target the RGD-binding integrins or TGF-β. These drugs have already shown a good safety profile and, therefore, can be faster brought into a trial to treat COVID-19 patients.

Actin Cytoskeleton and Regulation of TGFβ Signaling: Exploring Their Links

Human tissues, to maintain their architecture and function, respond to injuries by activating intricate biochemical and physical mechanisms that regulates intercellular communication crucial in maintaining tissue homeostasis. Coordination of the communication occurs through the activity of different actin cytoskeletal regulators, physically connected to extracellular matrix through integrins, generating a platform of biochemical and biomechanical signaling that is deregulated in cancer. Among the major pathways, a controller of cellular functions is the cytokine transforming growth factor β (TGFβ), which remains a complex and central signaling network still to be interpreted and explained in cancer progression. Here, we discuss the link between actin dynamics and TGFβ signaling with the aim of exploring their aberrant interaction in cancer.

Pulmonary toxicants and fibrosis: innate and adaptive immune mechanisms

Pulmonary fibrosis is characterized by destruction and remodeling of the lung due to an accumulation of collagen and other extracellular matrix components in the tissue. This results in progressive irreversible decreases in lung capacity, impaired gas exchange and eventually, hypoxemia. A number of inhaled and systemic toxicants including bleomycin, silica, asbestos, nanoparticles, mustard vesicants, nitrofurantoin, amiodarone, and ionizing radiation have been identified. In this article, we review the role of innate and adaptive immune cells and mediators they release in the pathogenesis of fibrotic pathologies induced by pulmonary toxicants. A better understanding of the pathogenic mechanisms underlying fibrogenesis may lead to the development of new therapeutic approaches for patients with these debilitating and largely irreversible chronic diseases.

Impact of the Local Inflammatory Environment on Mucosal Vitamin D Metabolism and Signaling in Chronic Inflammatory Lung Diseases

Vitamin D plays an active role in the modulation of innate and adaptive immune responses as well as in the protection against respiratory pathogens. Evidence for this immunomodulatory and protective role is derived from observational studies showing an association between vitamin D deficiency, chronic airway diseases and respiratory infections, and is supported by a range of experimental studies using cell culture and animal models. Furthermore, recent intervention studies have now shown that vitamin D supplementation reduces exacerbation rates in vitamin D-deficient patients with chronic obstructive pulmonary disease (COPD) or asthma and decreases the incidence of acute respiratory tract infections. The active vitamin D metabolite, 1,25-dihydroxy-vitamin D (1,25(OH)₂D), is known to contribute to the integrity of the mucosal barrier, promote killing of pathogens (via the induction of antimicrobial peptides), and to modulate inflammation and immune responses. These mechanisms may partly explain its protective role against infections and exacerbations in COPD and asthma patients. The respiratory mucosa is an important site of local 1,25(OH)₂D synthesis, degradation and signaling, a process that can be affected by exposure to inflammatory mediators. As a consequence, mucosal inflammation and other disease-associated factors, as observed in e.g., COPD and asthma, may modulate the protective actions of 1,25(OH)₂D. Here, we discuss the potential consequences of various disease-associated processes such as inflammation and exposure to pathogens and inhaled toxicants on vitamin D metabolism and local responses to 1,25(OH)₂D in both immune- and epithelial cells. We furthermore discuss potential consequences of disturbed local levels of 25(OH)D and 1,25(OH)₂D for chronic lung diseases. Additional insight into the relationship between disease-associated mechanisms and local effects of 1,25(OH)₂D is expected to contribute to the design of future strategies aimed at improving local levels of 1,25(OH)₂D and signaling in chronic inflammatory lung diseases.

miR-301a Suppression within Fibroblasts Limits the Progression of Fibrosis through the TSC1/mTOR Pathway

Pulmonary fibrosis has been characterized by abnormal proliferation of fibroblasts and massive deposition of the extracellular matrix, which results from a complex interplay of chronic injury and inflammatory responses. MicroRNA-301a (miR-301a) is activated by multiple inflammatory stimulators, contributing to multiple tumorigenesis and autoimmune diseases. This study showed that miR-301a was overexpressed in a bleomycin-induced murine model of pulmonary fibrosis and patients with idiopathic pulmonary fibrosis (IPF). In addition, miR-301a was activated by transforming growth factor β (TGF-β) and interleukin 6 (IL-6) in normal and IPF fibroblasts, which was markedly reversed by the signal transducer and activator of transcription 3 (STAT3) inhibitor. The genetic ablation of miR-301a in mice reduced bleomycin-induced lung fibrosis, and the downregulation of miR-301a restrained proliferation and activation of fibroblasts. Furthermore, this study demonstrated that TSC1 was a functional target of miR-301a in fibroblasts, and the negative regulation of TSC1 by miR-301a promoted the severity of pulmonary fibrosis through the mammalian target of rapamycin (mTOR) signaling pathway. The blocking of miR-301a by the intravenous injection of antagomiR-301a inhibited the proliferation of fibroblasts and the structural destruction of lung tissues in the bleomycin-induced lung fibrosis mouse model. The findings revealed the crucial role of the miR-301a/TSC1/mTOR axis in the pathogenesis of pulmonary fibrosis, suggesting that miR-301a might serve as a potential therapeutic target.

Bronchial lavage under fiberoptic bronchoscopy in the treatment of severe pulmonary infection

Objective:

To investigate the clinical efficacy of bronchial lavage under fiberoptic bronchoscopy in the treatment of severe pulmonary infection.

Methods:

One hundred forty eight patients with severe pulmonary infection who were admitted to our hospital from October 2016 to December 2017 were included in this study. According to the random number table method, they were divided into a control group and an observation group with 79 patients each. The control group was given conventional treatment, while the observation group was given bronchoalveolar lavage with fiberoptic bronchoscopy on the basis of the treatment in the control group. The clinical efficacy of the two groups was compared, the duration of mechanical ventilation, antibiotic use and symptoms improvement of the two groups were recorded, and the respiratory mechanics parameters, serum procalcitonin (PCT) and transforming growth factor β (TGF-β) level were measured before and after treatment.

Results:

The duration of mechanical ventilation, antibiotic use, respiratory failure correction, body temperature decline and white blood cell recovery in the observation group were significantly shorter than those in the control group (P<0.05). The total efficacy of the observation group was significantly higher than that of the control group (92.4% vs. 74.7%). The respiratory mechanics parameters of the two groups after treatment were higher than those before treatment (P<0.05) and the increase of the observation group was more obvious than that of the control group (P<0.05). The serum PCT and TGF-β levels of the two groups after treatment were lower than those before treatment (P<0.05), and the decrease level in the observation group was more obvious (P<0.05).

Conclusion:

Bronchial lavage under fiberoptic bronchoscopy can improve the clinical efficacy, accelerate the improvement of clinical symptoms and respiratory mechanics parameters, significantly reduce the PCT and TGF-β levels, and promote the rapid recovery of patients in the treatment of severe pulmonary infection.

Clinical quantification of the integrin αvβ6 by [18F]FB-A20FMDV2 positron emission tomography in healthy and fibrotic human lung (PETAL Study)

PURPOSE

The RGD-integrin, αvβ6, plays a role in the pathogenesis of pulmonary fibrosis through activation of transforming growth factor beta (TGFβ). This study sought to quantify expression of αvβ6 in the lungs of healthy humans and subjects with pulmonary fibrosis using the αvβ6-selective [18F]FB-A20FMDV2 PET ligand.

METHODS

[18F]FB-A20FMDV2 PET/CT scans were performed in healthy subjects and those with fibrotic lung disease. Standard uptake values (SUV) and volume of distribution (VT) were used to quantify αvβ6 expression. In subjects with fibrotic lung disease, qualitative assessment of the relationship between αvβ6 expression and the distribution of fibrosis on high resolution computed tomography was conducted.

RESULTS

A total of 15 participants (6 healthy, 7 with idiopathic pulmonary fibrosis (IPF) and 2 with connective tissue disease (CTD) associated PF) were enrolled. VT and SUV of [18F]FB-A20FMDV2 were increased in the lungs of subjects with pulmonary fibrosis (PF) compared with healthy subjects. Geometric mean VT (95% CI) was 0.88 (0.60, 1.29) mL/cm3 for healthy subjects, and 1.40 (1.22, 1.61) mL/cm3 for subjects with IPF; and SUV was 0.54 (0.36, 0.81) g/mL for healthy subjects and 1.03 (0.86, 1.22) g/mL for subjects with IPF. The IPF/healthy VT ratio (geometric mean, (95% CI of ratio)) was 1.59 (1.09, 2.32) (probability ratio > 1 = 0.988)) and the SUV ratio was 1.91 (1.27, 2.87) (probability ratio > 1 = 0.996). Increased uptake of [18F]FB-A20FMDV2 in PF was predominantly confined to fibrotic areas. [18F]FB-A20FMDV2 measurements were reproducible at an interval of 2 weeks. [18F]FB-A20FMDV2 was safe and well tolerated.

CONCLUSIONS

Lung uptake of [18F]FB-A20FMDV2, a measure of expression of the integrin αvβ6, was markedly increased in subjects with PF compared with healthy subjects.

A Staphylococcus pro-apoptotic peptide induces acute exacerbation of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal disease of unknown etiology; however, apoptosis of lung alveolar epithelial cells plays a role in disease progression. This intractable disease is associated with increased abundance of Staphylococcus and Streptococcus in the lungs, yet their roles in disease pathogenesis remain elusive. Here, we report that Staphylococcus nepalensis releases corisin, a peptide conserved in diverse staphylococci, to induce apoptosis of lung epithelial cells. The disease in mice exhibits acute exacerbation after intrapulmonary instillation of corisin or after lung infection with corisin-harboring S. nepalensis compared to untreated mice or mice infected with bacteria lacking corisin. Correspondingly, the lung corisin levels are significantly increased in human IPF patients with acute exacerbation compared to patients without disease exacerbation. Our results suggest that bacteria shedding corisin are involved in acute exacerbation of IPF, yielding insights to the molecular basis for the elevation of staphylococci in pulmonary fibrosis.

Mesenchymal stem cells may ameliorate inflammation in an ex vivo model of extracorporeal membrane oxygenation

INTRODUCTION

Mesenchymal stem cells exhibit immunomodulatory properties which are currently being investigated as a novel treatment option for Acute Respiratory Distress Syndrome. However, the feasibility and efficacy of mesenchymal stem cell therapy in the setting of extracorporeal membrane oxygenation is poorly understood. This study aimed to characterise markers of innate immune activation in response to mesenchymal stem cells during an ex vivo simulation of extracorporeal membrane oxygenation.

METHODS

Ex vivo extracorporeal membrane oxygenation simulations (n = 10) were conducted using a commercial extracorporeal circuit with a CO₂-enhanced fresh gas supply and donor human whole blood. Heparinised circuits (n = 4) were injected with 40 × 10⁶-induced pluripotent stem cell-derived human mesenchymal stem cells, while the remainder (n = 6) acted as controls. Simulations were maintained, under physiological conditions, for 240 minutes. Circuits were sampled at 15, 30, 60, 120 and 240 minutes and assessed for levels of interleukin-1β, interleukin-6, interleukin-8, interleukin-10, tumour necrosis factor-α, transforming growth factor-β1, myeloperoxidase and α-Defensin-1. In addition, haemoglobin, platelet and leukocyte counts were performed.

RESULTS

There was a trend towards reduced levels of pro-inflammatory cytokines in mesenchymal stem cell-treated circuits and a significant increase in transforming growth factor-β1. Blood cells and markers of neutrophil activation were reduced in mesenchymal stem cell circuits during the length of the simulation. As previously reported, the addition of mesenchymal stem cells resulted in a reduction of flow and increased trans-oxygenator pressures in comparison to controls.

CONCLUSIONS

The addition of mesenchymal stem cells during extracorporeal membrane oxygenation may cause an increase in transforming growth factor-β1. This is despite their ability to adhere to the membrane oxygenator. Further studies are required to confirm these findings.

Plant-derived oleanolic acid ameliorates markers of subclinical inflammation and innate immunity activation in diet-induced pre-diabetic rats

AIMS

Sub-clinical inflammation during pre-diabetes is one of the predisposing factors that facilitates the progression of pre-diabetes to type 2 diabetes. The administration of oleanolic acid (OA) with or without dietary intervention ameliorates the metabolic and cardiovascular complications in diet-induced pre-diabetes animal models of pre-diabetes. This study aimed to investigate whether OA can also suppress immune activation and ameliorate pro-inflammatory markers.

METHODS

Pre-diabetes was induced by feeding Sprague Dawley rats a high-fat high carbohydrate diet for 20 weeks. The pre-diabetic rats were then treated with OA (80 mg/kg) or metformin (500 mg/kg) in the presence or absence of dietary interventions for a period of 12 weeks. At the end of the treatment period, the animals were euthanised and whole blood was used for platelet and immune cell count while plasma was used for fibrinogen, cluster differentiation 40 ligand and pro-inflammatory cytokine evaluation.

RESULTS

The results of this study revealed that OA, with or without dietary intervention, improved lipid metabolism by restoring high-density lipoprotein (HDL) and low-density lipoproteins (LDLs) as well as reducing platelets and immune cell counts. Furthermore, OA also decreased plasma proinflammatory cytokines, including tumour necrosis factor-α and -1β. Markers of immune activation such as C-reactive protein, fibrinogen, and CD40L were also decreased upon administration of OA with or without dietary intervention.

CONCLUSION

The findings of this study suggest that OA may provide an alternative to prevent the progression of pre-diabetes to overt diabetes. This was evident by the reduction of differential white blood cell count and proinflammatory cytokines that exercebate insulin resistance. However, more studies are needed to elucidate the molecular mechanisms and to improve efficacy.

Mitochondrial Dysfunction as a Pathogenic Mediator of Chronic Obstructive Pulmonary Disease and Idiopathic Pulmonary Fibrosis

The mechanisms underlying the pathogenesis of chronic lung diseases, including chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis, remain incompletely understood. Mitochondria are vital cellular organelles crucial for energy generation, the maintenance of cellular metabolism, calcium homeostasis, intracellular signaling, and the regulation of cell death programs. Emerging evidence suggests that mitochondrial dysfunction plays a cardinal role in the initiation and progression of many human diseases, including chronic lung diseases. Upregulation of the autophagy program, a cellular adaptive mechanism for protein and organelle turnover, can occur in response to injury and may have a cell type-specific impact on the progression of disease. The selective autophagy subtype specific for mitochondria (mitophagy), regulated by PINK1 (phosphatase and tensin homolog-induced putative kinase 1), is a cellular response to accumulation of depolarized or injured mitochondria. Autophagy and mitophagy may be associated with either cellular protection or propagation of injury in a cell type-specific manner, and they may also be associated with modulation of cell death pathways. Genetic studies in mouse models have revealed opposing roles for PINK1 and/or mitophagy in the propagation of emphysema and fibrosis, whereas human studies have shown altered regulation of PINK1 in both idiopathic pulmonary fibrosis and COPD. We have also recently identified a role for mitophagy in regulating the cellular necroptosis program, with implications in COPD pathogenesis. Damage-associated molecular patterns released from injured mitochondria and/or necrotic cells may promote proinflammatory and profibrotic responses. In this review, we explore current experimental evidence for mitochondrial dysfunction as a key determinant in the pathogenesis of chronic lung diseases.

Identification of an emphysema-associated genetic variant near TGFB2 with regulatory effects in lung fibroblasts

Murine studies have linked TGF-β signaling to emphysema, and human genome-wide association studies (GWAS) studies of lung function and COPD have identified associated regions near genes in the TGF-β superfamily. However, the functional regulatory mechanisms at these loci have not been identified. We performed the largest GWAS of emphysema patterns to date, identifying 10 GWAS loci including an association peak spanning a 200 kb region downstream from TGFB2. Integrative analysis of publicly available eQTL, DNaseI, and chromatin conformation data identified a putative functional variant, rs1690789, that may regulate TGFB2 expression in human fibroblasts. Using chromatin conformation capture, we confirmed that the region containing rs1690789 contacts the TGFB2 promoter in fibroblasts, and CRISPR/Cas-9 targeted deletion of a ~ 100 bp region containing rs1690789 resulted in decreased TGFB2 expression in primary human lung fibroblasts. These data provide novel mechanistic evidence linking genetic variation affecting the TGF-β pathway to emphysema in humans.

TGF-β1 Impairs Vitamin D-Induced and Constitutive Airway Epithelial Host Defense Mechanisms

Airway epithelium is an important site for local vitamin D (VD) metabolism; this can be negatively affected by inflammatory mediators. VD is an important regulator of respiratory host defense, for example, by increasing the expression of hCAP18/LL-37. TGF-β1 is increased in chronic obstructive pulmonary disease (COPD), and known to decrease the expression of constitutive host defense mediators such as secretory leukocyte protease inhibitor (SLPI) and polymeric immunoglobulin receptor (pIgR). VD has been shown to affect TGF-β1-signaling by inhibiting TGF-β1-induced epithelial-to-mesenchymal transition. However, interactions between VD and TGF-β1, relevant for the understanding host defense in COPD, are incompletely understood. Therefore, the aim of the present study was to investigate the combined effects of VD and TGF-β1 on airway epithelial cell host defense mechanisms. Exposure to TGF-β1 reduced both baseline and VD-induced expression of hCAP18/LL-37, partly by increasing the expression of the VD-degrading enzyme CYP24A1. TGF-β1 alone decreased the number of secretory club and goblet cells and reduced the expression of constitutive host defense mediators SLPI, s/lPLUNC and pIgR, effects that were not modulated by VD. These results suggest that TGF-β1 may decrease the respiratory host defense both directly by reducing the expression of host defense mediators, and indirectly by affecting VD-mediated effects such as expression of hCAP18/LL-37.

AIM2 Inflammasome Activation Leads to IL-1α and TGF-β Release From Exacerbated Chronic Obstructive Pulmonary Disease-Derived Peripheral Blood Mononuclear Cells

Chronic obstructive pulmonary disease (COPD) is now the fourth-leading cause of death worldwide and its prevalence is increasing. The progressive decline of lung function and airway remodelling are a consequence of chronic inflammatory responses. It was recently postulated the involvement of the inflammasome in COPD, although the underlying mechanism/s still need to be elucidated. Therefore, we isolated peripheral blood mononuclear cells (PBMCs) from exacerbated/unstable COPD patients. The stimulation of PBMCs with an AIM2 inflammasome activator, Poly dA:dT, led to IL-1α, but not IL-1β, release. The release of this cytokine was caspase-1- and caspase-4-dependent and correlated to higher levels of 8-OH-dG in COPD compared to non-smoker and smoker-derived PBMCs. Interestingly, AIM2-depedent IL-1α release was responsible for higher TGF-β levels, crucial mediator during pro-fibrotic processes associated to COPD progression. In conclusion, our data highlight the involvement of AIM2/caspase-1/caspase-4 in IL-1α-induced TGF-β release in unstable COPD-derived PBMCs, opening new therapeutic perspectives for unstable COPD patients.

Pirfenidone, an Anti-Fibrotic Drug, Suppresses the Growth of Human Prostate Cancer Cells by Inducing G₁ Cell Cycle Arrest

Pirfenidone (PFD) is an anti-fibrotic drug used to treat idiopathic pulmonary fibrosis by inducing G₁ cell cycle arrest in fibroblasts. We hypothesize that PFD can induce G₁ cell cycle arrest in different types of cells, including cancer cells. To investigate the effects of PFD treatment on the growth of human prostate cancer (PCa) cells, we used an androgen-sensitive human PCa cell line (LNCaP) and its sublines (androgen-low-sensitive E9 and F10 cells and androgen-insensitive AIDL cells), as well as an androgen-insensitive human PCa cell line (PC-3). PFD treatment suppressed the growth of all PCa cells. Transforming growth factor β1 secretion was significantly increased in PFD-treated PCa cells. In both LNCaP and PC-3 cells, PFD treatment increased the population of cells in the G₀/G₁ phase, which was accompanied by a decrease in the S/G₂ cell population. CDK2 protein expression was clearly decreased in PFD-treated LNCaP and PC-3 cells, whereas p21 protein expression was increased in only PFD-treated LNCaP cells. In conclusion, PFD may serve as a novel therapeutic drug that induces G₁ cell cycle arrest in human PCa cells independently of androgen sensitivity. Thus, in the tumor microenvironment, PFD might target not only fibroblasts, but also heterogeneous PCa cells of varying androgen-sensitivity levels.

Reversion of in vivo fibrogenesis by novel chromone scaffolds

BACKGROUND

Myofibroblasts are known to play a key role in the development of idiopathic pulmonary fibrosis (IPF). Two drugs, pirfenidone and nintedanib, are the only approved therapeutic options for IPF, but their applications are limited due to their side effects. Thus, curative IPF drugs represent a huge unmet medical need.

METHODS

A mouse hepatic stellate cell (HSC) line was established that could robustly differentiate into myofibroblasts upon treatment with TGF-β. Eupatilin was assessed in diseased human lung fibroblasts from IPF patients (DHLFs) as well as in human lung epithelial cells (HLECs). The drug's performance was extensively tested in a bleomycin-induced lung fibrosis model (BLM). Global gene expression studies and proteome analysis were performed.

FINDINGS

Eupatilin attenuated disease severity of BLM in both preventative and therapeutic studies. The drug inhibited the in vitro transdifferantiation of DHLFs to myofibroblasts upon stimulation with TGF-β. No such induction of the in vitro transdifferantiation was observed in TGF-β treated HLECs. Specific carbons of eupatilin were essential for its anti-fibrotic activity. Eupatilin was capable of dismantling latent TGF-β complex, specifically by eliminating expression of the latent TGF-β binding protein 1 (LTBP1), in ECM upon actin depolymerization. Unlike eupatilin, pirfenidone was unable to block fibrosis of DHLFs or HSCs stimulated with TGF-β. Eupatilin attenuated phosphorylation of Smad3 by TGF-β. Eupatilin induced myofibroblasts to dedifferentiate into intermediate HCS-like cells.

INTERPRETATION

Eupatilin may act directly on pathogenic myofibroblasts, disarming them, whereas the anti-fibrotic effect of pirfenidone may be indirect. Eupatilin could increase the efficacy of IPF treatment to curative levels.

Emodin suppresses activation of hepatic stellate cells through p38 mitogen-activated protein kinase and Smad signaling pathways in vitro

The aim of this study was to evaluate the hypothesis that emodin inhibits extracellular matrix (ECM)-related gene expression in activated hepatic stellate cells (HSCs) by blocking canonical or/and noncanonical components of transforming growth factor β1 (TGFβ1) intracellular signaling. Here, we demonstrate that emodin suppressed the gene expression of HSCs activation markers type I collagen, fibronectin, and α-smooth muscle actin, as well as HSCs proliferation. Mechanistically, emodin suppresses TGFβ1, TGFβ receptor II, TGFβ receptor I, and Smad4 gene expression, as well as Smad luciferase activity. Simultaneously, emodin reduced p38 mitogen-activated protein kinase (p38^MAPK ) activity but not c-Jun N-terminal kinases and extracellular signal-regulated kinases 1 and 2 phosphorylation in HSC-T6 cells. Interestingly, deprivation of TGFβ using a neutralizing antibody abolished emodin-mediated inhibitions of the both Smad transcriptional activity and p38^MAPK phosphorylation. Furthermore, emodin-mediated inhibition of HSCs activation could be partially blocked by PD98059 inhibition of p38^MAPK or short hairpin RNA-imposed knockdown of Smad4. Conversely, simultaneous inhibition of Smad4 and p38^MAPK pathways completely reverses the effects of emodin, suggesting that Smad and p38^MAPK locate downstream of TGFβ1 and regulate collagen genes expression in HSCs. Collectively, these data suggest that emodin is a promising candidate for the treatment of hepatic fibrosis.

Chest pain in patients with COPD: the fascia's subtle silence

COPD is a progressive condition that leads to a pathological degeneration of the respiratory system. It represents one of the most important causes of mortality and morbidity in the world, and it is characterized by the presence of many associated comorbidities. Recent studies emphasize the thoracic area as one of the areas of the body concerned by the presence of pain with percentages between 22% and 54% in patients with COPD. This article analyzes the possible causes of mediastinal pain, including those less frequently taken into consideration, which concern the role of the fascial system of the mediastinum. The latter can be a source of pain especially when a chronic pathology is altering the structure of the connective tissue. We conclude that to consider the fascia in daily clinical activity may improve the therapeutic approach toward the patient.

Expression of TGF-beta receptor 1 and Smads in the tissues of primary spontaneous pneumothorax

BACKGROUND

Primary spontaneous pneumothorax (PSP) is a common disease which is often caused by the rupture of bullae in the lungs. The underlying pathogenesis of PSP remains unclear. Some molecules may be involved in the development of PSP potentially. The aim of this study was to investigate the expression of TGF-beta receptor 1 (TβR1), Smad2, Smad3 and Smad4 in the resected bullae of patients with PSP.

METHODS

From May 2015 to May 2016, 34 patients with PSP underwent video-assisted thoracoscopic surgery (VATS) bullectomy. Immunohistochemistry was performed to identify the expression of TβR1, Smad2, Smad3 and Smad4 in the resected pulmonary bullae tissues. The levels of these cytokines were calculated by immunoreactivity scoring system (IRS). Ten patients without pneumothorax associated disease were selected as the control group.

RESULTS

The analysis showed that the expression levels of TβR1, Smad2 and Smad4 were significantly higher in bullae tissues of patients with PSP than that in normal lung tissues (P=0.012, 0.031, 0.000 respectively). There was no significant difference between the expression level of Smad3 in bullae tissue of PSP patients and that in normal lung tissues of the control group (P=0.140). However, the absolute quantity of Smad3 expression in PSP bullae tissues was (4.2529±1.7193), scored by the IRS, which is higher than that in the control lung tissues (3.2600±2.2132). Also, the expression of TβR1, Smad2, Smad3 and Smad4 were not showed correlation with the clinical characteristics of PSP patients, such as age, sex, body mass index (BMI), recurrence and side of pneumothorax.

CONCLUSIONS

TβR1, Smad2 and Smad4 highly expressed in bullae tissues of PSP patients. Our findings suggested that TβR1, Smad2 and Smad4 may be related to the development of PSP bullae.

Safer approaches to therapeutic modulation of TGF-β signaling for respiratory disease

The transforming growth factor (TGF)-β cytokines play a central role in development and progression of chronic respiratory diseases. TGF-β overexpression in chronic inflammation, remodeling, fibrotic process and susceptibility to viral infection is established in the most prevalent chronic respiratory diseases including asthma, COPD, lung cancer and idiopathic pulmonary fibrosis. Despite the overwhelming burden of respiratory diseases in the world, new pharmacological therapies have been limited in impact. Although TGF-β inhibition as a therapeutic strategy carries great expectations, the constraints in avoiding compromising the beneficial pleiotropic effects of TGF-β, including the anti-proliferative and immune suppressive effects, have limited the development of effective pharmacological modulators. In this review, we focus on the pathways subserving deleterious and beneficial TGF-β effects to identify strategies for selective modulation of more distal signaling pathways that may result in agents with improved safety/efficacy profiles. Adverse effects of TGF-β inhibitors in respiratory clinical trials are comprehensively reviewed, including those of the marketed TGF-β modulators, pirfenidone and nintedanib. Precise modulation of TGF-β signaling may result in new safer therapies for chronic respiratory diseases.

TGF-β1 Suppresses the Type I IFN Response and Induces Mitochondrial Dysfunction in Alveolar Macrophages

TGF-β1 is a pleiotropic cytokine with an established role in fibrosis; however, the immunosuppressive effects of TGF-β1 are less characterized. Elevated levels of TGF-β1 are found in patients with acute and chronic lung diseases, and the underlying disease processes are exacerbated by respiratory viral infections. The alveolar macrophage is the first line of cellular defense against respiratory viral infections, and its response to infections is dependent on environmental cues. Using the mouse alveolar macrophage line, MH-S, and human CD14⁺ monocyte-derived macrophages, we examined the effects of TGF-β1 on the type I IFN antiviral response, macrophage polarization, and mitochondrial bioenergetics following a challenge with human respiratory syncytial virus (RSV). Our results showed that TGF-β1 treatment of macrophages decreased the antiviral and proinflammatory response, and suppressed basal, maximal, spare mitochondrial respiration, and mitochondrial ATP production. Challenge with RSV following TGF-β1 treatment further exacerbated mitochondrial dysfunction. The TGF-β1 and TGF-β1+RSV-treated macrophages had a higher frequency of apoptosis and diminished phagocytic capacity, potentially through mitochondrial stress. Disruption of TGF-β1 signaling or rescue of mitochondrial respiration may be novel therapeutically targetable pathways to improve macrophage function and prevent secondary bacterial infections that complicate viral respiratory infections.

TGFβ as a therapeutic target in cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease characterized by progressive lung disease. Most CF therapies focus on treating secondary pulmonary complications rather than addressing the underlying processes inducing airway remodeling and ineffective response to infection. Transforming growth factor beta (TGFβ) is a cytokine involved in fibrosis, inflammation, and injury response as well as a genetic modifier and biomarker of CF lung disease. Targeting the TGFβ pathway has been pursued in other diseases, but the mechanism of TGFβ effects in CF is less well understood. Areas covered: In this review, we discuss CF lung disease pathogenesis with a focus on potential links to TGFβ. TGFβ signaling in lung health and disease is reviewed. Recent studies investigating TGFβ's impact in CF airway epithelial cells are highlighted. Finally, an overview of potential therapies to target TGFβ signaling relevant to CF are addressed. Expert opinion: The broad impact of TGFβ signaling on numerous cellular processes in homeostasis and disease is both a strength and a challenge to developing TGFβ dependent therapeutics in CF. We discuss the challenges inherent in developing TGFβ-targeted therapy, identifying appropriate patient populations, and questions regarding the timing of treatment. Future directions for research into TGFβ focused therapeutics are discussed.

Aged polymorphonuclear leukocytes cause fibrotic interstitial lung disease in the absence of regulation by B cells

Pulmonary immunity requires tight regulation, as interstitial inflammation can compromise gas exchange and lead to respiratory failure. Here we found a greater number of aged CD11b^hiL-selectin^loCXCR4⁺ polymorphonuclear leukocytes (PMNs) in lung vasculature than in the peripheral circulation. Using pulmonary intravital microscopy, we observed lung PMNs physically interacting with B cells via β₂ integrins; this initiated neutrophil apoptosis, which led to macrophage-mediated clearance. Genetic deletion of B cells led to the accumulation of aged PMNs in the lungs without systemic inflammation, which caused pathological fibrotic interstitial lung disease that was attenuated by the adoptive transfer of B cells or depletion of PMNs. Thus, the lungs are an intermediary niche in the PMN lifecycle wherein aged PMNs are regulated by B cells, which restrains their potential to cause pulmonary pathology.