Recombinant human serum amyloid P in healthy volunteers and patients with pulmonary fibrosis

Serum amyloid P component: Structure, biological activity, and application in diagnosis and treatment of immune-associated diseases

Serum amyloid P component (SAP) is a member the innate immune humoral arm and participated in various processes, including the innate immune responses, tissue remodeling, and the pathogenesis of inflammatory diseases. Remarkably, SAP is a highly versatile immunomodulatory factor that can serve as a drug target for treating amyloid diseases and reduce inflammation, fibrosis degree, and respiratory disease. In this review, we focus on the biological activities of SAP and its application in different systemic immune-associated diseases. First, we reviewed the regulatory effects of SAP on innate immune cells and possible mechanisms. Second, we emphasized SAP as a diagnostic marker and therapeutic target for immune-associated diseases, including the neuropsychiatric disorders. Third, we presented several recommendations for regulating SAP in immune cell function and potential areas for future research. Some authorities consider SAP to be a pattern recognition molecule that plays multiple roles in the innate immune system and inflammation. Developing therapeutics that target SAP or its associated signaling pathways may be a promising strategy for treating immune-associated diseases.

Comparative Pharmacokinetics and Safety Assessment of 1st- and 2nd-Generation Zinpentraxin Alfa Drug Products in Healthy Volunteers: A Randomized Crossover Study

Zinpentraxin alfa is a recombinant form of the human pentraxin-2 that was studied in idiopathic pulmonary fibrosis (IPF). To improve the purity and yield of the drug material, a 2nd-generation drug product was developed. To characterize and compare the pharmacokinetic (PK) properties of the 1st- and 2nd-generation zinpentraxin alfa, PK studies were conducted in healthy volunteers (HVs). In a phase 1 randomized, double-blind, 2-sequence crossover, sequential 2-stage study (ISRCTN59409907), single intravenous (IV) doses of 1st- and 2nd-generation zinpentraxin alfa at 10 mg/kg were studied with a blinded interim analysis (IA) at the end of stage 1. Bioequivalence (BE) was achieved for the maximum observed plasma concentration (Cmax), but the overall exposure was higher for the 2nd- compared to the 1st-generation zinpentraxin alfa. The study was stopped after stage 1 as the gating criteria were met based on the result of the blinded IA. Safety profiles were similar for the 1st- and 2nd-generation drug products, and antidrug antibody (ADA) was not observed in this study.

Repeat-dose and embryo-fetal developmental toxicity of zinpentraxin alfa

Zinpentraxin alfa is a recombinant human pentraxin-2 (PTX-2) developed for the treatment of various fibrotic diseases with the hypothesis that supplementing endogenous PTX-2 levels through intravenous administration should increase its regulatory capacity in circulation and at the site of disease, thereby promoting healing and reducing fibrosis. Zinpentraxin alfa has been studied in various clinical trials, particularly in patients with idiopathic pulmonary fibrosis, where it has demonstrated efficacy in slowing decline in lung function in a phase 2 study. In the present investigation, we summarize findings from 14-day repeat-dose toxicity studies in rats and cynomolgus monkeys supporting early clinical development of zinpentraxin alfa. In addition, we also describe the findings from the embryo-fetal developmental (EFD) studies conducted in rats and rabbits, since the intended fibrosis patient population may include patients of childbearing potential. Zinpentraxin alfa was well tolerated by rats and monkeys in general toxicity studies with no treatment-related adverse effects, as well as by pregnant rats over the same dose range in a definitive EFD study. In contrast, substantial toxicity was observed in a rabbit dose-range-finder EFD study. Zinpentraxin alfa was poorly tolerated by pregnant rabbits and effects on the dams correlated with post-implantation fetal losses. The disparate effects of zinpentraxin alfa on embryo-fetal development between the two species suggests a potential unknown biological function of PTX-2 in pregnancy in the rabbit, which may be relevant to humans. Our findings warrant the consideration for highly effective contraceptive measures to avoid pregnancy in patients enrolled in clinical studies with zinpentraxin alfa.

Therapeutic Approaches for the Treatment of Interstitial Lung Disease: An Exploratory Review on Molecular Mechanisms

BACKGROUND

Interstitial Lung Diseases (ILDs) are characterized by shortness of breath caused by alveolar wall inflammation and/or fibrosis.

OBJECTIVE

Our review aims to study the depth of various variants of ILD, diagnostic procedures, pathophysiology, molecular dysfunction and regulation, subject and objective assessment techniques, pharmacological intervention, exercise training and various modes of delivery for rehabilitation.

METHOD

Articles are reviewed from PubMed and Scopus and search engines.

RESULTS

ILD is a rapidly progressing disease with a high mortality rate. Each variant has its own set of causal agents and expression patterns. Patients often find it challenging to self-manage due to persistent symptoms and a rapid rate of worsening. The present review elaborated on the pathophysiology, risk factors, molecular mechanisms, diagnostics, and therapeutic approaches for ILD will guide future requirements in the quest for innovative and tailored ILD therapies at the molecular and cellular levels.

CONCLUSION

The review highlights the rationale for conventional and novel therapeutic approaches for better management of ILD.

The Plastic Interplay between Lung Regeneration Phenomena and Fibrotic Evolution: Current Challenges and Novel Therapeutic Perspectives

Interstitial lung diseases (ILDs) are a heterogeneous group of pulmonary disorders characterized by variable degrees of inflammation, interstitial thickening, and fibrosis leading to distortion of the pulmonary architecture and gas exchange impairment. Among them, idiopathic pulmonary fibrosis (IPF) displays the worst prognosis. The only therapeutic options consist of the two antifibrotic drugs, pirfenidone and nintedanib, which limit fibrosis progression but do not reverse the lung damage. The shift of the pathogenetic paradigm from inflammatory disease to epithelium-derived disease has definitively established the primary role of type II alveolar cells, which lose their epithelial phenotype and acquire a mesenchymal phenotype with production of collagen and extracellular matrix (EMC) deposition. Some predisposing environmental and genetic factors (e.g., smoke, pollution, gastroesophageal reflux, variants of telomere and surfactant genes) leading to accelerated senescence set a pro-fibrogentic microenvironment and contribute to the loss of regenerative properties of type II epithelial cells in response to pathogenic noxae. This review provides a complete overview of the different pathogenetic mechanisms leading to the development of IPF. Then, we summarize the currently approved therapies and the main clinical trials ongoing. Finally, we explore the potentialities offered by agents not only interfering with the processes of fibrosis but also restoring the physiological properties of alveolar regeneration, with a particular focus on potentialities and concerns about cell therapies based on mesenchymal stem cells (MSCs), whose anti-inflammatory and immunomodulant properties have been exploited in other fibrotic diseases, such as graft versus host disease (GVHD) and COVID-19-related ARDS.

Novel Selective Quantification of Zinpentraxin Alfa Biotherapeutic in the Presence of Endogenous Isomer in Plasma Samples of Idiopathic Pulmonary Fibrosis Patients Using Immunoaffinity LC-MS

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal interstitial lung disease that affects three million patients worldwide and currently without an effective cure. Zinpentraxin alfa, a recombinant human pentraxin-2 (rhPTX-2) protein, has been evaluated as a potential drug candidate for the treatment of IPF. Clinical pharmacokinetic analysis of zinpentraxin alfa has been challenging historically due to interference from serum amyloid P component (SAP), an endogenous human pentraxin-2 protein. These molecules share an identical primary amino acid sequence and glycan composition; however, zinpentraxin alfa possesses α2,3-linked terminal sialic acid residues while SAP is an α2,6-linked isomer. By taking advantage of this only structural difference, we developed a novel assay strategy where α2,3-sialidase was used to selectively hydrolyze α2,3-linked sialic acid residues, resulting in desialylated zinpentraxin alfa versus unchanged sialylated SAP, following an immunoaffinity capture step. Subsequent tryptic digestion produced a unique surrogate asialo-glycopeptide from zinpentraxin alfa and allowed specific quantification of the biotherapeutic in human plasma. In addition, a common peptide shared by both molecules was selected as a surrogate to determine total hPTX-2 concentrations, i.e., sum of zinpentraxin alfa and SAP. The quantification methods for both zinpentraxin alfa and total hPTX-2 were validated and used in pharmacokinetic assessment in IPF patients. The preliminary results suggest that endogenous SAP levels remained largely constant in IPF patients throughout the treatment with zinpentraxin alfa. Our novel approach provides a general bioanalytical strategy to selectively quantify α2,3-sialylated glycoproteins in the presence of their corresponding α2,6-linked isomers.

Pentraxins in invertebrates and vertebrates: From structure, function and evolution to clinical applications

The immune system is divided into two broad categories, consisting of innate and adaptive immunity. As recognition and effector factors of innate immunity and regulators of adaptive immune responses, lectins are considered to be important defense chemicals against microbial pathogens, cell trafficking, immune regulation, and prevention of autoimmunity. Pentraxins, important members of animal lectins, play a significant role in protecting the body from pathogen infection and regulating inflammatory reactions. They can recognize and bind to a variety of ligands, including carbohydrates, lipids, proteins, nucleic acids and their complexes, and protect the host from pathogen invasion by activating the complement cascade and Fcγ receptor pathways. Based on the primary structure of the subunit, pentraxins are divided into short and long pentraxins. The short pentraxins are comprised of C-reactive protein (CRP) and serum amyloid P (SAP), and the most important member of the long pentraxins is pentraxin 3 (PTX3). The CRP and SAP exist in both vertebrates and invertebrates, while the PTX3 may be present only in vertebrates. The major ligands and functions of CRP, SAP and PTX3 and three activation pathways involved in the complement system are summarized in this review. Their different characteristics in various animals including humans, and their evolutionary trees are analyzed. The clinical applications of CRP, SAP and PTX3 in human are reviewed. Some questions that remain to be understood are also highlighted.

Evaluation of multiple immunoassay formats for detection of anti-drug antibodies to zinpentraxin alfa

Zinpentraxin alfa (rhPTX-2; PRM-151) is currently being developed for the treatment of fibrotic diseases such as idiopathic pulmonary fibrosis and myelofibrosis. Notably, because it is administered chronically and has an endogenously expressed counterpart, clinical studies of zinpentraxin alpha must include immunogenicity assessments. Since the typical homogenous bridging ELISA assay does not adequately measure anti-drug antibodies (ADAs) against zinpentraxin alfa, additional assay formats have been developed to evaluate immunogenicity of this therapeutic. Here, we present the evaluation of four distinct assay formats that were used to measure zinpentraxin alpha ADA: step-wise bridging, direct binding, total ADA, and the semi-homogeneous formats, based on multiple parameters including assay sensitivity, precision, and drug tolerance. This paper presents the full details of method development for each of the aforementioned assay formats including evaluation of sample pre-treatment, determination of cut point, and assessment of assay performance by analyzing a subset of clinical samples. Overall, the semi-homogenous ADA assay format with no sample pre-treatment was selected for the measurement of zinpentraxin alpha immunogenicity as it provided the desired sensitivity, drug tolerance, and reproducibility. Our study emphasizes the importance of assay format evaluation during drug development and the necessity to select the most suitable assay format and sample pre-treatment method by which to evaluate therapeutic drug immunogenicity.

Safety and efficacy of zinpentraxin alfa as monotherapy or in combination with ruxolitinib in myelofibrosis: stage I of a phase II trial

Pentraxin 2 (PTX-2; serum amyloid P component), a circulating endogenous regulator of the inflammatory response to tissue injury and fibrosis, is reduced in patients with myelofibrosis (MF). Zinpentraxin alfa (RO7490677, PRM-151) is a recombinant form of PTX-2 that has shown preclinical antifibrotic activity and no dose-limiting toxicities in phase I trials. We report results from stage 1 of a phase II trial of zinpentraxin alfa in patients with intermediate-1/2 or high-risk MF. Patients (n=27) received intravenous zinpentraxin α weekly (QW) or every 4 weeks (Q4W), as monotherapy or an additional therapy for patients on stable-dose ruxolitinib. The primary endpoint was overall response rate (ORR; investigatorassessed) adapted from International Working Group-Myeloproliferative Neoplasms Research and Treatment criteria. Secondary endpoints included modified Myeloproliferative Neoplasm-Symptom Assessment Form Total Symptom Score (MPN-SAF TSS) change, bone marrow (BM) MF grade reduction, pharmacokinetics, and safety. ORR at week 24 was 33% (n=9/27) and varied across individual cohorts (QW: 38% [3/8]; Q4W: 14% [1/7]; QW+ruxolitinib: 33% [2/6]; Q4W+ruxolitinib: 50% [3/6]). Five of 18 evaluable patients (28%) experienced a ≥50% reduction in MPN-SAF TSS, and six of 17 evaluable patients (35%) had a ≥1 grade improvement from baseline in BM fibrosis at week 24. Most treatment-emergent adverse events (AE) were grade 1-2, most commonly fatigue. Among others, anemia and thrombocytopenia were infrequent (n=3 and n=1, respectively). Treatment-related serious AE occurred in four patients (15%). Overall, zinpentraxin alfa showed evidence of clinical activity and tolerable safety as monotherapy and in combination with ruxolitinib in this open-label, non-randomized trial (clinicaltrials gov. Identifier: NCT01981850).

Development of a Cell-based Neutralizing Antibody Assay for Zinpentraxin Alfa: Challenges and Mitigation Strategies

Therapeutic protein drugs can potentially induce immune responses in patients and result in the production of anti-drug antibodies (ADAs), including a subset of ADAs called neutralizing antibodies (NAbs) that might cause loss of efficacy by inhibiting clinical activities of the drug. Herein, we describe the unique challenges encountered during the development of a fit-for-purpose cell-based NAb assay for a new protein modality, zinpentraxin alfa, including our strategies for assay design to overcome various matrix interferences and improve assay drug tolerance. We demonstrated that a typical biotin-drug extraction with acid dissociation (BEAD) approach alone was not sufficient to eliminate matrix interferences in this assay. Instead, the combination of the BEAD and ZebaTM spin size exclusion plate (SEP) was required to achieve the desirable assay performance. We also demonstrated that appropriate acidic buffers were critical in sample pretreatment to improve assay drug tolerance, which not only dissociated the drug/NAb immune complex but also effectively and irreversibly denatured the free drug. The final assay performed well with confirmed assay robustness and suitability for the clinical applications.

Therapeutic strategies targeting pro-fibrotic macrophages in interstitial lung disease

Idiopathic pulmonary fibrosis (IPF) is the representative phenotype of interstitial lung disease where severe scarring develops in the lung interstitium. Although antifibrotic treatments are available and have been shown to slow the progression of IPF, improved therapeutic options are still needed. Recent data indicate that macrophages play essential pro-fibrotic roles in the pathogenesis of pulmonary fibrosis. Historically, macrophages have been classified into two functional subtypes, "M1" and "M2," and it is well described that "M2" or "alternatively activated" macrophages contribute to fibrosis via the production of fibrotic mediators, such as TGF-β, CTGF, and CCL18. However, highly plastic macrophages may possess distinct functions and phenotypes in the fibrotic lung environment. Thus, M2-like macrophages in vitro and pro-fibrotic macrophages in vivo are not completely identical cell populations. Recent developments in transcriptome analysis, including single-cell RNA sequencing, have attempted to depict more detailed phenotypic characteristics of pro-fibrotic macrophages. This review will outline the role and characterization of pro-fibrotic macrophages in fibrotic lung diseases and discuss the possibility of treating lung fibrosis by preventing or reprogramming the polarity of macrophages. We also utilized a systematic approach to review the literature and identify novel and promising therapeutic agents that follow this treatment strategy.

Inhibitors of the Sialidase NEU3 as Potential Therapeutics for Fibrosis

Fibrosing diseases are a major medical problem, and are associated with more deaths per year than cancer in the US. Sialidases are enzymes that remove the sugar sialic acid from glycoconjugates. In this review, we describe efforts to inhibit fibrosis by inhibiting sialidases, and describe the following rationale for considering sialidases to be a potential target to inhibit fibrosis. First, sialidases are upregulated in fibrotic lesions in humans and in a mouse model of pulmonary fibrosis. Second, the extracellular sialidase NEU3 appears to be both necessary and sufficient for pulmonary fibrosis in mice. Third, there exist at least three mechanistic ways in which NEU3 potentiates fibrosis, with two of them being positive feedback loops where a profibrotic cytokine upregulates NEU3, and the upregulated NEU3 then upregulates the profibrotic cytokine. Fourth, a variety of NEU3 inhibitors block pulmonary fibrosis in a mouse model. Finally, the high sialidase levels in a fibrotic lesion cause an easily observed desialylation of serum proteins, and in a mouse model, sialidase inhibitors that stop fibrosis reverse the serum protein desialylation. This then indicates that serum protein sialylation is a potential surrogate biomarker for the effect of sialidase inhibitors, which would facilitate clinical trials to test the exciting possibility that sialidase inhibitors could be used as therapeutics for fibrosis.

SAP deficiency aggravates periodontitis possibly via C5a-C5aR signaling-mediated defective macrophage phagocytosis of Porphyromonas gingivalis

INTRODUCTION

Serum amyloid P component (SAP) regulates the innate immune system and microbial diseases. Periodontitis is an inflammatory oral disease developed by the host immune system's interaction with the dysbiotic oral microbiome, thereby SAP could play a role in periodontitis pathogenicity.

OBJECTIVES

To investigate the role of SAP in oral microbiome modulation and peridontitis pathogenicity.

METHODS

In this study, wildtype and SAP-knockout (KO) mice were used. Ligature-based periodontitis was developed in mice. Oral microbiome diversity was analyzed by 16 s rRNA sequencing. Macrophages and Porphyromonas gingivalis (P. gingivalis) co-culture system analyzed the effect of SAP in macrophage phagocytosis of P. gingivalis.

RESULTS

The level of SAP was upregulated in the periodontitis-affected periodontium of humans and mice but not in the liver and blood circulation. Periodontal macrophages were the key source of upregulated SAP in periodontitis. SAP-KO aggravated periodontal inflammation, periodontitis, and a higher number of M1-type inflammatory macrophage infiltration in the periodontium. The oral microbiome of SAP-KO periodontitis mice was altered with a higher abundance of Porphyromonas at the genus level. SAP-KO macrophages showed compromised phagocytosis of P. gingivalis in the co-culture system. Co-culture of SAP-KO macrophages and P. gingivalis induced the C5a expression and exogenous SAP treatment nullified this effect. Exogenous recombinant SAP treatment did not affect P. gingivalis growth and opsonization. PMX205, an antagonist of C5a, treatment robustly enhanced P. gingivalis phagocytosis by SAP-KO macrophages, indicating the involvement of the C5a-C5aR signaling in the compromised P. gingivalis phagocytosis by SAP-KO macrophages.

CONCLUSION

SAP deficiency aggravates periodontitis possibly via C5a-C5aR signaling-mediated defective macrophage phagocytosis of P. gingivalis. A higher abundance of P. gingivalis during SAP deficiency could promote M1 macrophage polarization and periodontitis. This finding suggests the possible protecting role of elevated levels of periodontal SAP against periodontitis progression.

Regeneration or Repair? The Role of Alveolar Epithelial Cells in the Pathogenesis of Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease (ILD) with unknown etiology in which gradual fibrotic scarring of the lungs leads to usual interstitial pneumonia (UIP) and, ultimately, to death. IPF affects three million people worldwide, and the only currently available treatments include the antifibrotic drugs nintedanib and pirfenidone, which effectively reduce fibrosis progression are, unfortunately, not effective in curing the disease. In recent years, the paradigm of IPF pathogenesis has shifted from a fibroblast-driven disease to an epithelium-driven disease, wherein, upon recurrent microinjuries, dysfunctional alveolar type II epithelial cells (ATII) are not only unable to sustain physiological lung regeneration but also promote aberrant epithelial–mesenchymal crosstalk. This creates a drift towards fibrosis rather than regeneration. In the context of this review article, we discuss the most relevant mechanisms involved in IPF pathogenesis with a specific focus on the role of dysfunctional ATII cells in promoting disease progression. In particular, we summarize the main causes of ATII cell dysfunction, such as aging, environmental factors, and genetic determinants. Next, we describe the known mechanisms of physiological lung regeneration by drawing a parallel between embryonic lung development and the known pathways involved in ATII-driven alveolar re-epithelization after injury. Finally, we review the most relevant interventional clinical trials performed in the last 20 years with the aim of underlining the urgency of developing new therapies against IPF that are not only aimed at reducing disease progression by hampering ECM deposition but also boost the physiological processes of ATII-driven alveolar regeneration.

Lung Fibrosis and Fibrosis in the Lungs: Is It All about Myofibroblasts?

In the lungs, fibrosis is a growing clinical problem that results in shortness of breath and can end up in respiratory failure. Even though the main fibrotic disease affecting the lung is idiopathic pulmonary fibrosis (IPF), which affects the interstitial space, there are many fibrotic events that have high and dangerous consequences for the lungs. Asthma, chronic obstructive pulmonary disease (COPD), excessive allergies, clearance of infection or COVID-19, all are frequent diseases that show lung fibrosis. In this review, we describe the different kinds of fibrosis and analyse the main types of cells involved-myofibroblasts and other cells, like macrophages-and review the main fibrotic mechanisms. Finally, we analyse present treatments for fibrosis in the lungs and highlight potential targets for anti-fibrotic therapies.

Quantitative proteomics analysis of human vitreous in rhegmatogenous retinal detachment associated with choroidal detachment by data-independent acquisition mass spectrometry

The prognosis of rhegmatogenous retinal detachment (RRD) with choroidal detachment (RRDCD) is often poor and complicated. This study focused on the identification of the characteristic proteins and signal pathways associated with the etiology of RRDCD and to provide guidance for diagnosis and treatment of RRDCD. In this study, vitreous humor samples were obtained from 16 RRDCD patients, 14 with RRD, 12 with idiopathic epiretinal macular membrane (IEMM), and 5 healthy controls from donated corpse eyes. Data-independent acquisition mass spectrometry and bioinformatics analysis were employed to identify differentially expressed proteins (DEPs). In the vitreous humor, 14,842 peptides were identified. Patients with RRDCD had 249 DEPs (93 upregulated and 156 downregulated), with 89 in patients with RRD and 61 in patients with IEMM. Enrichment analysis of the GO and Kyoto Encyclopedia of Genes and Genomes DEP databases indicated functional clusters related to inflammation and immunity, protein degradation and absorption, cell adhesion molecules (CAMs), the hedgehog signaling pathway, and lipid metabolism. Weighted gene co-expression network analysis showed that DEPs with positive co-expression of RRDCD participated in immune-related pathways led by the complement and coagulation cascade, whereas DEPs with negative co-expression of RRDCD participated in protein degradation and absorption, CAMs, and the hedgehog signaling pathway. In summary, our study provides important clues and the theoretical basis for exploring the pathogenesis, progression, and prognosis of ocular fundus disease.

Natural Product-Based Potential Therapeutic Interventions of Pulmonary Fibrosis

Pulmonary fibrosis (PF) is a disease-refractive lung condition with an increased rate of mortality. The potential factors causing PF include viral infections, radiation exposure, and toxic airborne chemicals. Idiopathic PF (IPF) is related to pneumonia affecting the elderly and is characterized by recurring scar formation in the lungs. An impaired wound healing process, defined by the dysregulated aggregation of extracellular matrix components, triggers fibrotic scar formation in the lungs. The potential pathogenesis includes oxidative stress, altered cell signaling, inflammation, etc. Nintedanib and pirfenidone have been approved with a conditional endorsement for the management of IPF. In addition, natural product-based treatment strategies have shown promising results in treating PF. In this study, we reviewed the recently published literature and discussed the potential uses of natural products, classified into three types-isolated active compounds, crude extracts of plants, and traditional medicine, consisting of mixtures of different plant products-in treating PF. These natural products are promising in the treatment of PF via inhibiting inflammation, oxidative stress, and endothelial mesenchymal transition, as well as affecting TGF-β-mediated cell signaling, etc. Based on the current review, we have revealed the signaling mechanisms of PF pathogenesis and the potential opportunities offered by natural product-based medicine in treating PF.

Idiopathic pulmonary fibrosis: Current and future treatment

Objectives

Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.

Data Source

The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.

Results

Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.

Conclusion

Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being.

Advances with pharmacotherapy for the treatment of interstitial lung disease

INTRODUCTION

In recent decades, the primary focus of pharmaceutical research in interstitial lung diseases (ILD) has been on idiopathic pulmonary fibrosis (IPF). Recently, pharmaceutical development has also focused on other forms of ILDs, including connective tissue diseases associated ILD, fibrotic hypersensitivity pneumonitis, and sarcoidosis.

AREAS COVERED

The authors summarize the advances in pharmacotherapy for the treatment of ILD. Specifically, the authors review the most recent studies and discuss the most recent research findings and future prospects.

EXPERT OPINION

Data collected over the past years have confirmed the efficacy of antifibrotic drugs on slowing disease progression in IPF. The usual strategy for CTD-ILD management is represented by the combined use of corticosteroids and immunosuppressive agents. There is an urgent need for new target therapies. The concept of progressive fibrosing ILD has emerged in the ILD community in recent years, which has led to grouping several diseases with a common disease behavior to find an effective treatment . At present, selecting the best therapy in ILDs should be reasonably performed on a case-by-case basis through a multidisciplinary team discussion in tertiary ILD centers, taking into consideration patients' symptoms, lung functional trends, and radiological changes.

Development of Anti-fibrotic Therapy in Stricturing Crohn's Disease: Lessons from Randomized Trials in Other Fibrotic Diseases

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective anti-fibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver and skin. In this review, we summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Management of Idiopathic Pulmonary Fibrosis

Progress in the past 2 decades has led to widespread use of 2 medications to slow loss of lung function in patients with pulmonary fibrosis. Treatment of individual patients with currently available pharmacotherapies can be limited by side effects, and neither drug has a consistent effect on patient symptoms or function. Several promising new pharmacotherapies are under development. Comprehensive management of pulmonary fibrosis hinges on shared decision making. Patient and caregiver education, and early identification and management of symptoms and comorbidities, can help improve quality of life.

Serum amyloid P component is an essential element of resistance against Aspergillus fumigatus

Serum amyloid P component (SAP, also known as Pentraxin 2; APCS gene) is a component of the humoral arm of innate immunity involved in resistance to bacterial infection and regulation of tissue remodeling. Here we investigate the role of SAP in antifungal resistance. Apcs^-/- mice show enhanced susceptibility to A. fumigatus infection. Murine and human SAP bound conidia, activate the complement cascade and enhance phagocytosis by neutrophils. Apcs^-/- mice are defective in vivo in terms of recruitment of neutrophils and phagocytosis in the lungs. Opsonic activity of SAP is dependent on the classical pathway of complement activation. In immunosuppressed mice, SAP administration protects hosts against A. fumigatus infection and death. In the context of a study of hematopoietic stem-cell transplantation, genetic variation in the human APCS gene is associated with susceptibility to invasive pulmonary aspergillosis. Thus, SAP is a fluid phase pattern recognition molecule essential for resistance against A. fumigatus.

Emerging drugs for the treatment of idiopathic pulmonary fibrosis: 2020 phase II clinical trials

INTRODUCTION

The enthusiasm generated by the approval of pirfenidone and nintedanib as the first effective therapies for IPF led the IPF scientific community to investigate an increasing number of novel agents in well-designed randomized controlled trials, in the hope to find a cure for these patients.

AREAS COVERED

This reviews the evidence from IPF phase II trials that were completed or started in 2020. Literature search was performed using Medline and Clinicaltrials.org databases.

EXPERT OPINION

Randomized clinical trials revolutionized the management of IPF, leading to the discovery of the first therapies capable of slowing down functional deterioration in these patients. The recently published findings of the first successful phase II trials since pirfenidone and nintedanib will hopefully inaugurate a new era in the therapeutic scenario of IPF, where consolidated treatments of proven efficacy and novel targeted agents contribute together to reach the final goal of halting the fibrotic process of this dreadful disease.

Regulatory Immune Cells in Idiopathic Pulmonary Fibrosis: Friends or Foes?

The immune system is receiving increasing attention for interstitial lung diseases, as knowledge on its role in fibrosis development and response to therapies is expanding. Uncontrolled immune responses and unbalanced injury-inflammation-repair processes drive the initiation and progression of idiopathic pulmonary fibrosis. The regulatory immune system plays important roles in controlling pathogenic immune responses, regulating inflammation and modulating the transition of inflammation to fibrosis. This review aims to summarize and critically discuss the current knowledge on the potential role of regulatory immune cells, including mesenchymal stromal/stem cells, regulatory T cells, regulatory B cells, macrophages, dendritic cells and myeloid-derived suppressor cells in idiopathic pulmonary fibrosis. Furthermore, we review the emerging role of regulatory immune cells in anti-fibrotic therapy and lung transplantation. A comprehensive understanding of immune regulation could pave the way towards new therapeutic or preventive approaches in idiopathic pulmonary fibrosis.

Combined analysis of serum SAP and PRSS2 for the differential diagnosis of CD and UC

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory disease. Crone's disease (CD) and ulcerative colitis (UC) are types of IBD. There is a need for a more accurate, noninvasive biomarker to distinguish CD from UC.

PURPOSE

To verify the diagnostic value of combined serum trypsin 2 (PRSS2) and serum amyloid P component (SAP) evaluation in distinguishing CD from UC.

METHODS

The subjects included 28 normal controls (NC) as well as 44 UC, 72CD, 16 colorectal cancer (CRC), 10 colorectal polyps, and 10 cancer cases. Serum SAP, PRSS2, CRP, and CEA were measured and compared.

RESULTS

The concentration of CEA in CRC and other gastrointestinal tumors was significantly higher than that in UC, CD, and colorectal polyps. The concentration of CRP was significantly higher in UC and CD than that in the healthy group, but there were no significant differences when compared to the intestinal polyp group. Serum PRSS2 concentration was significantly higher in the UC and CD groups than that in the colorectal polyp group, and the average serum concentration of SAP in CD was significantly higher compared to UC. In patients with colorectal polyps, there was no correlation between PRSS2 and CRP. ROC curve analysis showed that the AUC of PRSS2 used to distinguish IBD patients from healthy controls or colorectal polyp patients was 0.730 and 0.774, respectively. The AUC of SAP used to distinguish CD from UC was 0.706. The AUC of combined PRSS2 and SAP was not different from the AUC for individual SAP. Finally, we demonstrated that the expression of SAP in CD patient tissues was significantly higher than that in UC patients.

CONCLUSION

The combined analysis of serum SAP and PRSS2 has differential diagnostic value for CD and UC.

Idiopathic pulmonary fibrosis: Molecular mechanisms and potential treatment approaches

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease with high mortality that commonly occurs in middle-aged and older adults. IPF, characterized by a decline in lung function, often manifests as exertional dyspnea and cough. Symptoms result from a fibrotic process driven by alveolar epithelial cells that leads to increased migration, proliferation, and differentiation of lung fibroblasts. Ultimately, the differentiation of fibroblasts into myofibroblasts, which synthesize excessive amounts of extracellular matrix proteins, destroys the lung architecture. However, the factors that induce the fibrotic process are unclear. Diagnosis can be a difficult process; the gold standard for diagnosis is the multidisciplinary conference. Practical biomarkers are needed to improve diagnostic and prognostic accuracy. High-resolution computed tomography typically shows interstitial pneumonia with basal and peripheral honeycombing. Gas exchange and diffusion capacity are impaired. Treatments are limited, although the anti-fibrotic drugs pirfenidone and nintedanib can slow the progression of the disease. Lung transplantation is often contraindicated because of age and comorbidities, but it improves survival when successful. The incidence and prevalence of IPF has been increasing and there is an urgent need for improved therapies. This review covers the detailed cellular and molecular mechanisms underlying IPF progression as well as current treatments and cutting-edge research into new therapeutic targets.

Extracellular signaling in Dictyostelium

In the last few decades, we have learned a considerable amount about how eukaryotic cells communicate with each other, and what it is the cells are telling each other. The simplicity of Dictyostelium discoideum, and the wide variety of available tools to study this organism, makes it the equivalent of a hydrogen atom for cell and developmental biology. Studies using Dictyostelium have pioneered a good deal of our understanding of eukaryotic cell communication. In this review, we will present a brief overview of how Dictyostelium cells use extracellular signals to attract each other, repel each other, sense their local cell density, sense whether the nearby cells are starving or stressed, count themselves to organize the formation of structures containing a regulated number of cells, sense the volume they are in, and organize their multicellular development. Although we are probably just beginning to learn what the cells are telling each other, the elucidation of Dictyostelium extracellular signals has already led to the development of possible therapeutics for human diseases.

The therapy of idiopathic pulmonary fibrosis: what is next?

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease, characterised by progressive scarring of the lung and associated with a high burden of disease and early death. The pathophysiological understanding, clinical diagnostics and therapy of IPF have significantly evolved in recent years. While the recent introduction of the two antifibrotic drugs pirfenidone and nintedanib led to a significant reduction in lung function decline, there is still no cure for IPF; thus, new therapeutic approaches are needed. Currently, several clinical phase I-III trials are focusing on novel therapeutic targets. Furthermore, new approaches in nonpharmacological treatments in palliative care, pulmonary rehabilitation, lung transplantation, management of comorbidities and acute exacerbations aim to improve symptom control and quality of life. Here we summarise new therapeutic attempts and potential future approaches to treat this devastating disease.

Serum Amyloid P and a Dendritic Cell-Specific Intercellular Adhesion Molecule-3-Grabbing Nonintegrin Ligand Inhibit High-Fat Diet-Induced Adipose Tissue and Liver Inflammation and Steatosis in Mice

High-fat diet (HFD)-induced inflammation is associated with a variety of health risks. The systemic pentraxin serum amyloid P (SAP) inhibits inflammation. SAP activates the high-affinity IgG receptor Fcγ receptor I (FcγRI; CD64) and the lectin receptor dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN; CD209). Herein, we show that for mice on an HFD, injections of SAP and a synthetic CD209 ligand (1866) reduced HFD-increased adipose and liver tissue inflammation, adipocyte differentiation, and lipid accumulation in adipose tissue. HFD worsened glucose tolerance test results and caused increased adipocyte size; for mice on an HFD, SAP improved glucose tolerance test results and reduced adipocyte size. Mice on an HFD had elevated serum levels of IL-1β, IL-23, interferon (IFN)-β, IFN-γ, monocyte chemoattractant protein 1 [MCP-1; chemokine (C-C motif) ligand 2 (CCL2)], and tumor necrosis factor-α. SAP reduced serum levels of IL-23, IFN-β, MCP-1, and tumor necrosis factor-α, whereas 1866 reduced IFN-γ. In vitro, SAP, but not 1866, treated cells isolated from white fat tissue (stromal vesicular fraction) produced the anti-inflammatory cytokine IL-10. HFD causes steatosis, and both SAP and 1866 reduced it. Conversely, compared with control mice, SAP knockout mice fed on a normal diet had increased white adipocyte cell sizes, increased numbers of inflammatory cells in adipose and liver tissue, and steatosis; and these effects were exacerbated on an HFD. SAP and 1866 may inhibit some, but not all, of the effects of a high-fat diet.

Pharmacoproteomics reveal novel protective activity of bromodomain containing 4 inhibitors on vascular homeostasis in TLR3-mediated airway remodeling

Small molecule inhibitors of the epigenetic regulator bromodomain-containing protein 4 (BRD4) are potential therapeutics for viral and allergen-induced airway remodeling. A limitation of their preclinical advancement is the lack of detailed understanding of mechanisms of action and biomarkers of effect. We report a systems-level pharmacoproteomics in a standardized murine model of toll-like receptor TLR3-NFκB/RelA innate inflammation in the absence or presence of a highly selective BRD4 inhibitor (ZL0454) or nonselective bromodomain and extraterminal domain inhibitor (JQ1). Proteomics of bronchoalveolar lavage fluid (BALF) secretome and exosomal proteins from this murine model revealed increased, selective, capillary leak associated with pericyte-myofibroblast transition, a phenomenon blocked by BRD4 inhibitors. BALF proteomics also suggested that ZL0454 better reduced the vascular leakage and extracellular matrix deposition than JQ1. A significant subset of inflammation-mediated remodeling factors was also identified in a mouse model of idiopathic pulmonary fibrosis produced by bleomycin. BALF exosome analysis indicated that BRD4 inhibitors reduced the induction of exosomes enriched in coagulation factors whose presence correlated with interstitial fibrin deposition. Finally, BALF samples from humans with severe asthma demonstrated similar upregulations of ORM2, APCS, SPARCL1, FGA, and FN1, suggesting their potential as biomarkers for early detection of airway remodeling and/or monitoring of therapy response. SIGNIFICANCE: Repetitive and chronic viral upper respiratory tract infections trigger toll-like receptor (TLR)3-NFκB/RelA mediated airway remodeling which is linked to a progressive decline in pulmonary function in patients with asthma and chronic obstructive pulmonary disease. Small molecule inhibitors of the epigenetic regulator bromodomain-containing protein 4 (BRD4) are potential therapeutics for viral and allergen-induced airway remodeling. A limitation of their preclinical advancement is the lack of detailed understanding of mechanisms of action and biomarkers of effect. Our study revealed that the activation of (TLR)3-NFκB/RelA pathway in the lung induced an elevation in coagulation, complement, and platelet factors, indicating the increased vascular leak during airway remodeling. The mechanism of vascular leakage was chronic inflammation-induced pericyte-myofibroblast transition, which was blocked by BRD4 inhibitors. Finally, proteomics analysis of the bronchoalveolar lavage fluid samples from humans with severe asthma demonstrated similar findings that we observed in the animal model.

Serum Amyloid P Component Binds Fungal Surface Amyloid and Decreases Human Macrophage Phagocytosis and Secretion of Inflammatory Cytokines

In patients with invasive fungal diseases, there is often little cellular inflammatory response. We tested the idea that binding of the human constitutive plasma protein serum amyloid P component (SAP) (also called PTX2) to Candida albicans dampens the innate immune response to this fungus. Many pathogenic fungi have cell surface amyloid-like structures important for adhesion and biofilm formation. Human SAP bound to fungi that expressed functional cell surface amyloid, but SAP had minimal binding to fungi with reduced expression of cell surface amyloid. In the absence of SAP, phagocytosis of fungi by human macrophages was potentiated by expression of amyloid on the fungi. SAP binding to fungi inhibited their phagocytosis by macrophages. Macrophages pretreated with SAP displayed reduced fungal phagocytosis, reduced secretion of inflammatory cytokines (IFN-γ, IL-6, and TNF-α), and increased secretion of the anti-inflammatory cytokine IL-10. SAP bound to fungi or added to the medium upregulated the expression of the anti-inflammatory receptor CD206 on macrophages. These findings suggest that SAP bound to amyloid-like structures on fungal cells dampens the host cellular immune response in fungal diseases such as invasive candidiasis.IMPORTANCE Macrophages are a key part of our innate immune system and are responsible for recognizing invading microbes, ingesting them, and sending appropriate signals to other immune cells. We have found that human macrophages can recognize invading yeast pathogens that have a specific molecular pattern of proteins on their surfaces: these proteins have structures similar to the structures of amyloid aggregates in neurodegenerative diseases like Alzheimer's disease. However, this surface pattern also causes the fungi to bind a serum protein called serum amyloid P component (SAP). In turn, the SAP-coated yeasts are poorly recognized and seldom ingested by the macrophages, and the macrophages have a more tolerant and less inflammatory response in the presence of SAP. Therefore, we find that surface structures on the yeast can alter how the macrophages react to invading microbes.

The Development of Serum Amyloid P as a Possible Therapeutic

Pentraxins such as serum amyloid P (SAP; also known as PTX2) regulate several aspects of the innate immune system. SAP inhibits the differentiation of monocyte-derived fibroblast-like cells called fibrocytes, promotes the formation of immuno-regulatory macrophages, and inhibits neutrophil adhesion to extracellular matrix proteins. In this minireview, we describe how these effects of SAP have led to its possible use as a therapeutic, and how modulating SAP effects might be used for other therapeutics. Fibrosing diseases such as pulmonary fibrosis, cardiac fibrosis, liver fibrosis, and renal fibrosis are associated with 30-45% of deaths in the US. Fibrosis involves both fibrocyte differentiation and profibrotic macrophage differentiation, and possibly because SAP inhibits both of these processes, in 9 different animal models, SAP inhibited fibrosis. In Phase 1B and Phase 2 clinical trials, SAP injections reduced the decline in lung function in pulmonary fibrosis patients, and in a small Phase 2 trial SAP injections reduced fibrosis in myelofibrosis patients. Acute respiratory distress syndrome/ acute lung injury (ARDS/ALI) involves the accumulation of neutrophils in the lungs, and possibly because SAP inhibits neutrophil adhesion, SAP injections reduced the severity of ARDS in an animal model. Conversely, depleting SAP is a potential therapeutic for amyloidosis, topically removing SAP from wound fluid speeds wound healing in animal models, and blocking SAP binding to one of its receptors makes cultured macrophages more aggressive toward tuberculosis bacteria. These results suggest that modulating pentraxin signaling might be useful for a variety of diseases.

Idiopathic Pulmonary Fibrosis (IPF): An Overview

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease characterised by chronic, progressive scarring of the lungs and the pathological hallmark of usual interstitial pneumonia. Current paradigms suggest alveolar epithelial cell damage is a key initiating factor. Globally, incidence of the disease is rising, with associated high morbidity, mortality, and economic healthcare burden. Diagnosis relies on a multidisciplinary team approach with exclusion of other causes of interstitial lung disease. Over recent years, two novel antifibrotic therapies, pirfenidone and nintedanib, have been developed, providing treatment options for many patients with IPF, with several other agents in early clinical trials. Current efforts are directed at identifying key biomarkers that may direct more customized patient-centred healthcare to improve outcomes for these patients in the future.

Identification of Endpoints for Development of Antifibrosis Drugs for Treatment of Crohn's Disease

BACKGROUND & AIMS

Intestinal fibrosis is a challenge to management of patients with Crohn's disease (CD); there is an urgent need to expedite development of antifibrosis drugs for this disease. The International Organization for the Study of Inflammatory Bowel Disease (IOIBD) aimed to identify a set of endpoints that can be used to determine efficacy of antifibrosis agents tested in clinical trials of patients with CD.

METHODS

We conducted a systematic review to identify clinical, radiologic, biochemical, endoscopic, and composite endpoints used in assessing activity of fibrostenosing CD and response to treatment, and determined their operational properties. A panel of IOIBD experts performed a consensus process to identify the best endpoints for inclusion in clinical trials, through a 2-round, Delphi-style online survey.

RESULTS

A total of 36 potentially relevant endpoints for intestinal fibrosis were selected and assessed. Forty-eight physicians with expertise in inflammatory bowel disease, from 5 regions (North America, Europe, Middle East, Asia/Pacific, and Latin America), participated in the Delphi consensus process. A core set of 13 endpoints (complete clinical response, long-term efficacy, sustained clinical benefit, treatment failure, radiological remission, normal quality of life, clinical remission without steroids, therapeutic failure, deep remission, complete absence of occlusive symptoms, symptom-free survival, bowel damage progression, and no disability) were rated as critical. Agreement was high among the experts.

CONCLUSIONS

Members of the IOIBD reached expert consensus on a set of endpoints that can be used to assess antifibrosis agents in trials of patients with CD. Studies are needed to clarify methods for measuring these outcomes and validate measurement instruments.

Effect of Recombinant Human Pentraxin 2 vs Placebo on Change in Forced Vital Capacity in Patients With Idiopathic Pulmonary Fibrosis: A Randomized Clinical Trial

IMPORTANCE

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with poor prognosis. Approved therapies do not halt disease progression.

OBJECTIVE

To determine the effect of recombinant human pentraxin 2 vs placebo on change from baseline to week 28 in mean forced vital capacity (FVC) percentage of predicted value.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2, randomized, double-blind, placebo-controlled trial conducted at 18 sites in 7 countries of eligible patients with IPF (N = 117; aged 40-80 years; FVC ≥50% and ≤90% predicted; ratio of forced expiratory volume in the first second/FVC >0.70; diffusing capacity for carbon monoxide [Dlco] ≥25% and ≤90% predicted; and distance of ≥150 m on the 6-minute walk test). Study period was August 2015-May 2017.

INTERVENTIONS

Patients were randomized to receive either recombinant human pentraxin 2 (10 mg/kg intravenous every 4 weeks, n = 77) or placebo (n = 39) for 24 weeks, and stratified by concurrent IPF treatment status.

MAIN OUTCOMES AND MEASURES

The primary end point was the least-squares mean change in FVC percentage of predicted value from baseline to week 28 (minimal clinically important difference, decline of 2%-6%). Secondary end points included mean change in lung volumes (total, normal, and interstitial lung abnormalities) on high-resolution computed tomography (HRCT) and 6-minute walk distance (minimal clinically important difference, 24-45 m).

RESULTS

Of 117 randomized patients, 116 received at least 1 dose of study drug (mean age, 68.6 years; 81.0% men; mean time since IPF diagnosis, 3.8 years), and 111 (95.7%) completed the study. The least-squares mean change in FVC percentage of predicted value from baseline to week 28 in patients treated with recombinant human pentraxin 2 was -2.5 vs -4.8 for those in the placebo group (difference, +2.3 [90% CI, 1.1 to 3.5]; P = .001). No significant treatment differences were observed in total lung volume (difference, 93.5 mL [90% CI, -27.7 to 214.7]), quantitative parenchymal features on HRCT (normal lung volume difference, -1.2% [90% CI, -4.4 to 1.9]; interstitial lung abnormalities difference, 1.1% [90% CI, -2.2 to 4.3]), or measurement of Dlco (difference, -0.4 [90% CI, -2.6 to 1.7]). The change in 6-minute walk distance was -0.5 m for patients treated with recombinant human pentraxin 2 vs -31.8 m for those in the placebo group (difference, +31.3 m [90% CI, 17.4 to 45.1]; P < .001). The most common adverse events in the recombinant human pentraxin 2 vs placebo group were cough (18% vs 5%), fatigue (17% vs 10%), and nasopharyngitis (16% vs 23%).

CONCLUSIONS AND RELEVANCE

In this preliminary study, recombinant human pentraxin 2 vs placebo resulted in a slower decline in lung function over 28 weeks for patients with idiopathic pulmonary fibrosis. Further research should more fully assess efficacy and safety.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02550873.

Identification of potential serum biomarkers of acute paraquat poisoning in humans using an iTRAQ quantitative proteomic

Paraquat (PQ) poisoning has high mortality rates in many countries. Due to it readily being absorbed through the gastrointestinal tract and rapidly excreted in the urine, few biomarkers possess satisfactory specificity and sensitivity in diagnostic and forensic practices. To investigate serum biomarkers in patients with PQ poisoning, pooled sera was analyzed using a proteomic approach based on iTRAQ coupled LC-MS/MS. Of the 413 proteins identified with high confidence, 81 were found to be differentially expressed (1.5-fold change) in the sera of patients with PQ poisoning. The differential expression pattern of 4 of these proteins was validated by enzyme-linked immunosorbent assay (ELISA) in clinical samples. A sera sample from a PQ poisoning patient has shown relatively increased abundance of S100A8 and S100A9. The overexpression of S100A8 and S100A9 was further validated in the lung tissue of PQ-treated rat associated with lung damage. Meanwhile, we identified another two down-expressed proteins, transferrin receptor protein 1 (TfR1) and serum amyloid P-component (SAP), which may be also practicable in human clinical samples as PQ poisoning serum biomarkers. Furthermore, receiver operating characteristic curve analysis confirmed that the expression levels of S100 alarmins, TfR1 and SAP in patient serum could provide a discriminatory diagnostic test for predicting PQ poisoning in patients. Therefore, our results suggest that increased serum levels of S100 alarmins and decreased serum levels of TfR1 and SAP may constitute potential biomarkers for the prediction of PQ poisoning in humans, and might be novel therapeutic targets in PQ poisoning.

The diversity of myeloid immune cells shaping wound repair and fibrosis in the lung

In healthy circumstances the immune system coordinates tissue repair responses in a tight balance that entails efficient inflammation for removal of potential threats, proper wound closure, and regeneration to regain tissue function. Pathological conditions, continuous exposure to noxious agents, and even ageing can dysregulate immune responses after injury. This dysregulation can lead to a chronic repair mechanism known as fibrosis. Alterations in wound healing can occur in many organs, but our focus lies with the lung as it requires highly regulated immune and repair responses with its continuous exposure to airborne threats. Dysregulated repair responses can lead to pulmonary fibrosis but the exact reason for its development is often not known. Here, we review the diversity of innate immune cells of myeloid origin that are involved in tissue repair and we illustrate how these cell types can contribute to the development of pulmonary fibrosis. Moreover, we briefly discuss the effect of age on innate immune responses and therefore on wound healing and we conclude with the implications of current knowledge on the avenues for future research.

C-reactive protein (CRP) but not the related pentraxins serum amyloid P and PTX3 inhibits the proliferation and induces apoptosis of the leukemia cell line Mono Mac 6

Background

Pentraxins are a family of highly conserved secreted proteins that regulate the innate immune system, including monocytes and macrophages. C-reactive protein (CRP) is a plasma protein whose levels can rise to 1000 μg/ml from the normal <3 μg/ ml during inflammation.

Results

We find that CRP inhibits proliferation of the human myeloid leukemia cell line Mono Mac 6 with an IC50 of 75 μg/ ml by inducing apoptosis of these cells. The related proteins serum amyloid P (SAP) and pentraxin 3 (PTX3) do not inhibit Mono Mac 6 proliferation. CRP has no significant effect on the proliferation of other leukemia cell lines such as HL-60, Mono Mac 1, K562, U937, or THP-1, or the survival of normal peripheral blood cells. The effect of CRP appears to be dependent on the CRP receptor FcγRI, and is negatively regulated by a phosphatidylinositol −3-kinase pathway.

Conclusion

These data reveal differential signaling by pentraxins on immune cells, and suggest that CRP can regulate the proliferation of some myeloid leukemia cells.

Novel Therapies for Myelofibrosis

PURPOSE OF REVIEW

The purpose of the review was to provide a contemporary update of novel agents and targets under investigation in myelofibrosis in the Janus kinase (JAK) inhibitor era.

RECENT FINDINGS

Myelofibrosis (MF) is a clonal stem cell disease characterized by marrow fibrosis and a heterogeneous disease phenotype with a variable degree of splenomegaly, cytopenias, and constitutional symptoms that significantly impact quality of life and survival. Overactive JAK/STAT signaling is a hallmark of MF. The only approved therapy for MF, JAK1/2 inhibitor ruxolitinib, can ameliorate splenomegaly, improve symptoms, and prolong survival in some patients. Therapeutic challenges remain, however. Myelosuppression limits the use of ruxolitinib in some patients, eventual drug resistance is common, and the underlying malignant clone persists despite therapy. A deeper understanding of the pathogenesis of MF has informed the development of additional agents. Promising targets under investigation include JAK1 and JAK2 and downstream intermediates in related signaling pathways, epigenetic modifiers, pro-inflammatory cytokines, and immune regulators.

Investigational drugs for idiopathic pulmonary fibrosis

INTRODUCTION

IPF is a specific form of chronic fibrosing interstitial pneumonia of unknown cause, characterized by progressive worsening in lung function and an unfavorable prognosis. Current concepts on IPF pathogenesis are based on a dysregulated wound healing response, leading to an over production of extracellular matrix. Based on recent research however, several other mechanisms are now proposed as potential targets for novel therapeutic strategies. Areas covered: This review analyzes the current investigational strategies targeting extracellular matrix deposition, tyrosine-kinase antagonism, immune and autoimmune response, and cell-based therapy. A description of the pathogenic rationale implied in each novel therapeutic approach is summarized. Expert opinion: New IPF drugs are being evaluated in the context of phase 1 and 2 clinical trials. Nevertheless, many drugs that have shown efficacy in preclinical studies, failed to exhibit the same positive effect when translated to humans. A possible explanation for these failures might be related to the known limitations of animal models of the disease. The recent development of 3D systems composed of cells from individual patients that recreate an ex-vivo model of IPF, could lead to significant improvements in disease pathogenesis and treatment. New drugs could be tested on more genuine models and clinicians could tailor therapy based on patient's response.

Pentraxins in the activation and regulation of innate immunity

Humoral fluid phase pattern recognition molecules (PRMs) are a key component of the activation and regulation of innate immunity. Humoral PRMs are diverse. We focused on the long pentraxin PTX3 as a paradigmatic example of fluid phase PRMs. PTX3 acts as a functional ancestor of antibodies and plays a non-redundant role in resistance against selected microbes in mouse and man and in the regulation of inflammation. This molecule interacts with complement components, thus modulating complement activation. In particular, PTX3 regulates complement-driven macrophage-mediated tumor progression, acting as an extrinsic oncosuppressor in preclinical models and selected human tumors. Evidence collected over the years suggests that PTX3 is a biomarker and potential therapeutic agent in humans, and pave the way to translation of this molecule into the clinic.

Serum amyloid P component: A novel potential player in vessel degeneration in CADASIL

In cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), granular osmiophilic material (GOM) may play some roles in inducing cerebrovascular events. To elucidate the pathogenesis of CADASIL, we used laser microdissection and liquid chromatography-tandem mass spectrometry to analyze cerebrovascular lesions of patients with CADASIL for GOM. The analyses detected serum amyloid P component (SAP), annexin A2, and periostin as the proteins with the largest increase in the samples, which also demonstrated NOTCH3. For the three proteins, anti-human SAP antibody had the strongest reaction in the lesions where the anti-human NOTCH3 antibody showed positive staining. Moreover, immunofluorescence staining with the two antibodies clearly showed co-localization of SAP and NOTCH3. mRNA analyses indicated no positive SAP expression in the brain materials, which suggested that the source of SAP found in the GOM was only the liver. A solid phase enzyme-linked immunosorbent assay confirmed the binding of SAP with NOTCH3. Serum SAP concentrations were neither up-regulated nor down-regulated in CADASIL patients, when compared with those in control subjects. SAP may play an important role in GOM formation although precise mechanisms remain to be elucidated.