ADAM-family metalloproteinases in lung inflammation: potential therapeutic targets

Neutrophil-Derived Proteases in Lung Inflammation: Old Players and New Prospects

Neutrophil-derived proteases are critical to the pathology of many inflammatory lung diseases, both chronic and acute. These abundant enzymes play roles in key neutrophil functions, such as neutrophil extracellular trap formation and reactive oxygen species release. They may also be released, inducing tissue damage and loss of tissue function. Historically, the neutrophil serine proteases (NSPs) have been the main subject of neutrophil protease research. Despite highly promising cell-based and animal model work, clinical trials involving the inhibition of NSPs have shown mixed results in lung disease patients. As such, the cutting edge of neutrophil-derived protease research has shifted to proteases that have had little-to-no research in neutrophils to date. These include the cysteine and serine cathepsins, the metzincins and the calpains, among others. This review aims to outline the previous work carried out on NSPs, including the shortcomings of some of the inhibitor-orientated clinical trials. Our growing understanding of other proteases involved in neutrophil function and neutrophilic lung inflammation will then be discussed. Additionally, the potential of targeting these more obscure neutrophil proteases will be highlighted, as they may represent new targets for inhibitor-based treatments of neutrophil-mediated lung inflammation.

ADAM33's Role in Asthma Pathogenesis: An Overview

Asthma is a complex chronic respiratory disease characterized by airway hyperresponsiveness, inflammation, and obstruction. Many genes have been identified as associated with asthma but none with such substantial significance as the ADAM33 gene due to its role in airway remodeling and bronchial hyperresponsiveness. This review summarizes the current knowledge on the genetic and functional aspects of ADAM33 in asthma pathogenesis. We highlight its genetic variants associated with asthma susceptibility and severity, as well as the functional effects of ADAM33 on airway remodeling, smooth muscle cell proliferation, and its interplay with environmental factors. Additionally, we discuss the potential clinical implications of ADAM33 as a therapeutic target for asthma management.

An ADAM10 Exosite Inhibitor Is Efficacious in an In Vivo Collagen-Induced Arthritis Model

Rheumatoid arthritis is a systemic autoimmune inflammatory disease that affects millions of people worldwide. There are multiple disease-modifying anti-rheumatic drugs available; however, many patients do not respond to any treatment. A disintegrin and metalloproteinase 10 has been suggested as a potential new target for RA due to its role in the release of multiple pro- and anti-inflammatory factors from cell surfaces. In the present study, we determined the pharmacokinetic parameters and in vivo efficacy of a compound CID3117694 from a novel class of non-zinc-binding inhibitors. Oral bioavailability was demonstrated in the blood and synovial fluid after a 10 mg/kg dose. To test efficacy, we established the collagen-induced arthritis model in mice. CID3117694 was administered orally at 10, 30, and 50 mg/kg/day for 28 days. CID3117694 was able to dose-dependently improve the disease score, decrease RA markers in the blood, and decrease signs of inflammation, hyperplasia, pannus formation, and cartilage erosion in the affected joints compared to the untreated control. Additionally, mice treated with CID 3117694 did not exhibit any clinical signs of distress, suggesting low toxicity. The results of this study suggest that the inhibition of ADAM10 exosite can be a viable therapeutic approach to RA.

Descriptive and Functional Genomics in Neonatal Respiratory Distress Syndrome: From Lung Development to Targeted Therapies

In this up-to-date study, we first aimed to highlight the genetic and non-genetic factors associated with respiratory distress syndrome (RDS) while also focusing on the genomic aspect of this condition. Secondly, we discuss the treatment options and the progressing therapies based on RNAs or gene therapy. To fulfill this, our study commences with lung organogenesis, a highly orchestrated procedure guided by an intricate network of conserved signaling pathways that ultimately oversee the processes of patterning, growth, and differentiation. Then, our review focuses on the molecular mechanisms contributing to both normal and abnormal lung growth and development and underscores the connections between genetic and non-genetic factors linked to neonatal RDS, with a particular emphasis on the genomic aspects of this condition and their implications for treatment choices and the advancing therapeutic approaches centered around RNAs or gene therapy.

Endothelial ADAM10 utilization defines a molecular pathway of vascular injury in mice with bacterial sepsis

The endothelium plays a critical role in the host response to infection and has been a focus of investigation in sepsis. While it is appreciated that intravascular thrombus formation, severe inflammation, and loss of endothelial integrity impair tissue oxygenation during sepsis, the precise molecular mechanisms that lead to endothelial injury remain poorly understood. We demonstrate here that endothelial ADAM10 was essential for the pathogenesis of Staphylococcus aureus sepsis, contributing to α-toxin-mediated (Hla-mediated) microvascular thrombus formation and lethality. As ADAM10 is essential for endothelial development and homeostasis, we examined whether other major human sepsis pathogens also rely on ADAM10-dependent pathways in pathogenesis. Mice harboring an endothelium-specific knockout of ADAM10 were protected against lethal Pseudomonas aeruginosa and Streptococcus pneumoniae sepsis, yet remained fully susceptible to group B streptococci and Candida albicans sepsis. These studies illustrate a previously unknown role for ADAM10 in sepsis-associated endothelial injury and suggest that understanding pathogen-specific divergent host pathways in sepsis may enable more precise targeting of disease.

Optimization of fluorescent substrates for ADAM17 and their utility in the detection of diabetes

ADAM17 (a disintegrin and metalloproteinase 17) is a sheddase that releases various types of membrane-associated proteins, including adhesive molecules, cytokines and their receptors, and inflammatory mediators. Evidence suggests that the enzyme is involved in the proteolytic cleavage of antiaging transmembrane protein Klotho (KL). What is more, reduced serum and urinary KL levels are observed in the early stages of chronic kidney disease. This study aimed to optimise the ADAM17 specific and selective fluorescent substrates. Then, the obtained substrate was used to detect the enzyme in urine samples of patients diagnosed with diabetes. It turned out that in all cases we were able to detect proteolytic activity, which was the opposite of the healthy samples.

A ketogenic diet can mitigate SARS-CoV-2 induced systemic reprogramming and inflammation

The ketogenic diet (KD) has demonstrated benefits in numerous clinical studies and animal models of disease in modulating the immune response and promoting a systemic anti-inflammatory state. Here we investigate the effects of a KD on systemic toxicity in mice following SARS-CoV-2 infection. Our data indicate that under KD, SARS-CoV-2 reduces weight loss with overall improved animal survival. Muted multi-organ transcriptional reprogramming and metabolism rewiring suggest that a KD initiates and mitigates systemic changes induced by the virus. We observed reduced metalloproteases and increased inflammatory homeostatic protein transcription in the heart, with decreased serum pro-inflammatory cytokines (i.e., TNF-α, IL-15, IL-22, G-CSF, M-CSF, MCP-1), metabolic markers of inflammation (i.e., kynurenine/tryptophane ratio), and inflammatory prostaglandins, indicative of reduced systemic inflammation in animals infected under a KD. Taken together, these data suggest that a KD can alter the transcriptional and metabolic response in animals following SARS-CoV-2 infection with improved mice health, reduced inflammation, and restored amino acid, nucleotide, lipid, and energy currency metabolism.

Identification of membrane proteins regulated by ADAM15 by SUSPECS proteomics

ADAM15 is a member of the disintegrin-metalloproteinase family of sheddases, which plays a role in several biological processes including cartilage homeostasis. In contrast with well-characterized ADAMs, such as the canonical sheddases ADAM17 and ADAM10, little is known about substrates of ADAM15 or how the enzyme exerts its biological functions. Herein, we used "surface-spanning enrichment with click-sugars (SUSPECS)" proteomics to identify ADAM15 substrates and/or proteins regulated by the proteinase at the cell surface of chondrocyte-like cells. Silencing of ADAM15 by siRNAs significantly altered membrane levels of 13 proteins, all previously not known to be regulated by ADAM15. We used orthogonal techniques to validate ADAM15 effects on 3 of these proteins which have known roles in cartilage homeostasis. This confirmed that ADAM15-silencing increased cell surface levels of the programmed cell death 1 ligand 2 (PDCD1LG2) and reduced cell surface levels of vasorin and the sulfate transporter SLC26A2 through an unknown post-translational mechanism. The increase of PDCD1LG2 by ADAM15 knockdown, a single-pass type I transmembrane protein, suggested it could be a proteinase substrate. However, shed PDCD1LG2 could not be detected even by a data-independent acquisition mass spectrometry, a highly sensitive method for identification and quantification of proteins in complex protein samples, suggesting that ADAM15 regulates PDCD1LG2 membrane levels by a mechanism different from ectodomain shedding.

Quantitative Proteomics Reveals Transforming Growth Factor β Receptor Targeted by Resveratrol and Hesperetin Coformulation in Endothelial Cells

The endothelium is the frontline target of multiple metabolic stressors and pharmacological agents. As a consequence, endothelial cells (ECs) display highly dynamic and diverse proteome profiles. We describe here the culture of human aortic ECs from healthy and type 2 diabetic donors, the treatment with a small molecular coformulation of trans-resveratrol and hesperetin (tRES+HESP), followed by proteomic analysis of whole-cell lysate. A number of 3666 proteins were presented in all of the samples and thus further analyzed. We found that 179 proteins had a significant difference between diabetic ECs vs. healthy ECs, while 81 proteins had a significant change upon the treatment of tRES+HESP in diabetic ECs. Among them, 16 proteins showed a difference between diabetic ECs and healthy ECs and the difference was reversed by the tRES+HESP treatment. Follow-up functional assays identified activin A receptor-like type 1 and transforming growth factor β receptor 2 as the most pronounced targets suppressed by tRES+HESP in protecting angiogenesis in vitro. Our study has revealed the global differences in proteins and biological pathways in ECs from diabetic donors, which are potentially reversible by the tRES+HESP formula. Furthermore, we have identified the TGFβ receptor as a responding mechanism in ECs treated with this formula, shedding light on future studies for deeper molecular characterization.

The Role of MMPs in the Era of CFTR Modulators: An Additional Target for Cystic Fibrosis Patients?

Cystic fibrosis (CF) is a high-prevalence disease characterized by significant lung remodeling, responsible for high morbidity and mortality worldwide. The lung structural changes are partly due to proteolytic activity associated with inflammatory cells such as neutrophils and macrophages. Matrix metalloproteases (MMPs) are the major proteases involved in CF, and recent literature data focused on their potential role in the pathogenesis of the disease. In fact, an imbalance of proteases and antiproteases was observed in CF patients, resulting in dysfunction of protease activity and loss of lung homeostasis. Currently, many steps forward have been moved in the field of pharmacological treatment with the recent introduction of triple-combination therapy targeting the CFTR channel. Despite CFTR modulator therapy potentially being effective in up to 90% of patients with CF, there are still patients who are not eligible for the available therapies. Here, we introduce experimental drugs to provide updates on therapy evolution regarding a proportion of CF non-responder patients to current treatment, and we summarize the role of MMPs in pathogenesis and as future therapeutic targets of CF.

Role for the metalloproteinase ADAM28 in the control of airway inflammation, remodelling and responsiveness in asthma

Background

Asthma is characterized by morphological modifications of the airways (inflammation and remodelling) and bronchial hyperresponsiveness. Mechanisms linking these two key features of asthma are still poorly understood. ADAM28 (a disintegrin and metalloproteinase 28) might play a role in asthma pathophysiology. ADAM28 exists as membrane-bound and soluble forms and is mainly expressed by lymphocytes and epithelial cells.

Methods

ADAM28^-/- mice and ADAM28^+/+ counterparts were sensitized and exposed to ovalbumin (OVA). Airway responsiveness was measured using the flexiVent^® system. After sacrifice, bronchoalveolar lavage (BAL) was performed and lungs were collected for analysis of airway inflammation and remodelling.

Results

The expression of the soluble form of ADAM28 was lower in the lungs of OVA-exposed mice (as compared to PBS-exposed mice) and progressively increased in correlation with the duration of allergen exposure. In lungs of ADAM28^-/- mice exposed to allergens, the proportion of Th2 cells among CD 4 + cells and the number of B cells were decreased. Bronchial responsiveness was lower in ADAM28^-/- mice exposed to allergens and similar to the responsiveness of sham-challenged mice. Similarly, features of airway remodelling (collagen deposition, smooth muscle hyperplasia, mucous hyperplasia) were significantly less developed in OVA-exposed ADAM28^-/- animals in sharp contrasts to ADAM28^+/+. In addition, we report the first evidence of ADAM28 RNA expression by lung fibroblasts and we unveil a decreased capacity of lung fibroblasts extracted from OVA-exposed ADAM28^-/- mice to proliferate as compared to those extracted from OVA-exposed ADAM28^+/+ suggesting a direct contribution of this enzyme to the modulation of airway remodelling.

Conclusion

These results suggest that ADAM28 might be a key contributor to the pathophysiology of asthma.

Proteolysis and Deficiency of α1-Proteinase Inhibitor in SARS-CoV-2 Infection

The SARS-CoV-2 pandemic had stimulated the emergence of numerous publications on the α1-proteinase inhibitor (α1-PI, α1-antitrypsin), especially when it was found that the regions of high mortality corresponded to the regions with deficient α1-PI alleles. By analogy with the data obtained in the last century, when the first cause of the genetic deficiency of α1-antitrypsin leading to elastase activation in pulmonary emphysema was proven, it can be supposed that proteolysis hyperactivation in COVID-19 may be associated with the impaired functions of α1-PI. The purpose of this review was to systematize the scientific data and critical directions for translational studies on the role of α1-PI in SARS-CoV-2-induced proteolysis hyperactivation as a diagnostic marker and a therapeutic target. This review describes the proteinase-dependent stages of viral infection: the reception and penetration of the virus into a cell and the imbalance of the plasma aldosterone-angiotensin-renin, kinin, and blood clotting systems. The role of ACE2, TMPRSS, ADAM17, furin, cathepsins, trypsin- and elastase-like serine proteinases in the virus tropism, the activation of proteolytic cascades in blood, and the COVID-19-dependent complications is considered. The scientific reports on α1-PI involvement in the SARS-CoV-2-induced inflammation, the relationship with the severity of infection and comorbidities were analyzed. Particular attention is paid to the acquired α1-PI deficiency in assessing the state of patients with proteolysis overactivation and chronic non-inflammatory diseases, which are accompanied by the risk factors for comorbidity progression and the long-term consequences of COVID-19. Essential data on the search and application of protease inhibitor drugs in the therapy for bronchopulmonary and cardiovascular pathologies were analyzed. The evidence of antiviral, anti-inflammatory, anticoagulant, and anti-apoptotic effects of α1-PI, as well as the prominent data and prospects for its application as a targeted drug in the SARS-CoV-2 acquired pneumonia and related disorders, are presented.

Proteolytically generated soluble Tweak Receptor Fn14 is a blood biomarker for γ-secretase activity

Fn14 is a cell surface receptor with key functions in tissue homeostasis and injury but is also linked to chronic diseases. Despite its physiological and medical importance, the regulation of Fn14 signaling and turnover is only partly understood. Here, we demonstrate that Fn14 is cleaved within its transmembrane domain by the protease γ‐secretase, resulting in secretion of the soluble Fn14 ectodomain (sFn14). Inhibition of γ‐secretase in tumor cells reduced sFn14 secretion, increased full‐length Fn14 at the cell surface, and enhanced TWEAK ligand‐stimulated Fn14 signaling through the NFκB pathway, which led to enhanced release of the cytokine tumor necrosis factor. γ‐Secretase‐dependent sFn14 release was also detected ex vivo in primary tumor cells from glioblastoma patients, in mouse and human plasma and was strongly reduced in blood from human cancer patients dosed with a γ‐secretase inhibitor prior to chimeric antigen receptor (CAR)‐T‐cell treatment. Taken together, our study demonstrates a novel function for γ‐secretase in attenuating TWEAK/Fn14 signaling and suggests the use of sFn14 as an easily measurable pharmacodynamic biomarker to monitor γ‐secretase activity in vivo.

Pulmonary Delivery of Levamisole Nanoparticles as an Immunomodulator Affecting Th and a Potential ADAM10 Inhibitor to Ameliorate Severe Allergic Asthma

Asthma is a common chronic lung disease without absolute treatment, and hypersensitivity reactions and type 2 immune responses are responsible for asthma pathophysiology. ADAM10 as a metalloproteinase transmembrane protein is critical for development of Th2 responses, and levamisole as an anthelmintic drug has immunomodulatory effects, which not only regulates ADAM10 activity but also can suppress the bone marrow and neutrophil production. Therefore, in the present study, nanoparticles were used as a levamisole delivery system to reduce bone marrow suppression, and the immunomodulatory and ADAM10 inhibitory effects of levamisole were studied in allergic asthma. Asthmatic mice were treated with PLGA-levamisole nanoparticles. Then, AHR, BALF, and blood cell counts, levels of the IgG1 subclass, total and OVA-specific IgE, IL2, IL-4, IL-5, IL-10, IL-13, IL-17, IL-25, IL-33, INF-γ, and TNF-α, gene expression of FoxP3, T-bet, RORγt, PU.1, GATA3, FcεRII, CysLT1R, eotaxin, and ADAM10, and lung histopathology were evaluated. PLGA-LMHCl with considered characteristics could control airway hyper-responsiveness, eosinophils in the BALF, levels of immunoglobulins, Th2-, Th9-, and Th17-derived cytokines and pivotal genes, eosinophilic inflammation, hyperplasia of the goblet cell, and hyperproduction of mucus and could increase Th1- and Treg-derived cytokines and also pivotal genes. It could also modulate the ADAM10 activity and had no effect on the number of neutrophils in the bloodstream. The novel safe nanodrug had no side effect on the bone marrow to produce neutrophils and could control the allegro-immuno-inflammatory response of asthma.

RNA-sequencing and mass-spectrometry proteomic time-series analysis of T-cell differentiation identified multiple splice variants models that predicted validated protein biomarkers in inflammatory diseases

Profiling of mRNA expression is an important method to identify biomarkers but complicated by limited correlations between mRNA expression and protein abundance. We hypothesised that these correlations could be improved by mathematical models based on measuring splice variants and time delay in protein translation. We characterised time-series of primary human naïve CD4+ T cells during early T helper type 1 differentiation with RNA-sequencing and mass-spectrometry proteomics. We performed computational time-series analysis in this system and in two other key human and murine immune cell types. Linear mathematical mixed time delayed splice variant models were used to predict protein abundances, and the models were validated using out-of-sample predictions. Lastly, we re-analysed RNA-seq datasets to evaluate biomarker discovery in five T-cell associated diseases, further validating the findings for multiple sclerosis (MS) and asthma. The new models significantly out-performing models not including the usage of multiple splice variants and time delays, as shown in cross-validation tests. Our mathematical models provided more differentially expressed proteins between patients and controls in all five diseases. Moreover, analysis of these proteins in asthma and MS supported their relevance. One marker, sCD27, was validated in MS using two independent cohorts for evaluating response to treatment and disease prognosis. In summary, our splice variant and time delay models substantially improved the prediction of protein abundance from mRNA expression in three different immune cell types. The models provided valuable biomarker candidates, which were further validated in MS and asthma.

ADAM10 and ADAM17 promote SARS-CoV-2 cell entry and spike protein-mediated lung cell fusion

The severe‐acute‐respiratory‐syndrome‐coronavirus‐2 (SARS‐CoV‐2) is the causative agent of COVID‐19, but host cell factors contributing to COVID‐19 pathogenesis remain only partly understood. We identify the host metalloprotease ADAM17 as a facilitator of SARS‐CoV‐2 cell entry and the metalloprotease ADAM10 as a host factor required for lung cell syncytia formation, a hallmark of COVID‐19 pathology. ADAM10 and ADAM17, which are broadly expressed in the human lung, cleave the SARS‐CoV‐2 spike protein (S) in vitro, indicating that ADAM10 and ADAM17 contribute to the priming of S, an essential step for viral entry and cell fusion. ADAM protease‐targeted inhibitors severely impair lung cell infection by the SARS‐CoV‐2 variants of concern alpha, beta, delta, and omicron and also reduce SARS‐CoV‐2 infection of primary human lung cells in a TMPRSS2 protease‐independent manner. Our study establishes ADAM10 and ADAM17 as host cell factors for viral entry and syncytia formation and defines both proteases as potential targets for antiviral drug development.

[Proteolysis and deficiency of α1-proteinase inhibitor in SARS-CoV-2 infection]

The SARS-CoV-2 pandemia had stimulated the numerous publications emergence on the α1-proteinase inhibitor (α1-PI, α1-antitrypsin), primarily when it was found that high mortality in some regions corresponded to the regions with deficient α1-PI alleles. By analogy with the last century's data, when the root cause of the α1-antitrypsin, genetic deficiency leading to the elastase activation in pulmonary emphysema, was proven. It is evident that proteolysis hyperactivation in COVID-19 may be associated with α1-PI impaired functions. The purpose of this review is to systematize scientific data, critical directions for translational studies on the role of α1-PI in SARS-CoV-2-induced proteolysis hyperactivation as a diagnostic marker and a target in therapy. This review describes the proteinase-dependent stages of a viral infection: the reception and virus penetration into the cell, the plasma aldosterone-angiotensin-renin, kinins, blood clotting systems imbalance. The ACE2, TMPRSS, ADAM17, furin, cathepsins, trypsin- and elastase-like serine proteinases role in the virus tropism, proteolytic cascades activation in blood, and the COVID-19-dependent complications is presented. The analysis of scientific reports on the α1-PI implementation in the SARS-CoV-2-induced inflammation, the links with the infection severity, and comorbidities were carried out. Particular attention is paid to the acquired α1-PI deficiency in assessing the patients with the proteolysis overactivation and chronic non-inflammatory diseases that are accompanied by the risk factors for the comorbidities progression, and the long-term consequences of COVID-19 initiation. Analyzed data on the search and proteases inhibitory drugs usage in the bronchopulmonary cardiovascular pathologies therapy are essential. It becomes evident the antiviral, anti-inflammatory, anticoagulant, anti-apoptotic effect of α1-PI. The prominent data and prospects for its application as a targeted drug in the SARS-CoV-2 acquired pneumonia and related disorders are presented.

Quantitative Proteomics Reveals That ADAM15 Can Have Proteolytic-Independent Functions in the Steady State

A disintegrin and metalloproteinase 15 (ADAM15) is a member of the ADAM family of sheddases. Its genetic ablation in mice suggests that ADAM15 plays an important role in a wide variety of biological functions, including cartilage homeostasis. Nevertheless, while the substrate repertoire of other members of the ADAM family, including ADAM10 and ADAM17, is largely established, little is known about the substrates of ADAM15 and how it exerts its biological functions. Herein, we used unbiased proteomics to identify ADAM15 substrates and proteins regulated by the proteinase in chondrocyte-like HTB94 cells. ADAM15 silencing did not induce major changes in the secretome composition of HTB94 cells, as revealed by two different proteomic approaches. Conversely, overexpression of ADAM15 remodeled the secretome, with levels of several secreted proteins being altered compared to GFP-overexpressing controls. However, the analysis did not identify potential substrates of the sheddase, i.e., transmembrane proteins released by ADAM15 in the extracellular milieu. Intriguingly, secretome analysis and immunoblotting demonstrated that ADAM15 overexpression increased secreted levels of tissue inhibitor of metalloproteinases 3 (TIMP-3), a major regulator of extracellular matrix turnover. An inactive form of ADAM15 led to a similar increase in the inhibitor, indicating that ADAM15 regulates TIMP-3 secretion by an unknown mechanism independent of its catalytic activity. In conclusion, high-resolution quantitative proteomics of HTB94 cells manipulated to have increased or decreased ADAM15 expression did not identify canonical substrates of the proteinase in the steady state, but it revealed that ADAM15 can modulate the secretome in a catalytically-independent manner.

Berberine Suppresses Leukocyte Adherence by Downregulating CX3CL1 Expression and Shedding and ADAM10 in Lipopolysaccharide-Stimulated Vascular Endothelial Cells

Berberine exerts therapeutic effects in inflammation-associated diseases. In a lipopolysaccharide (LPS)-induced endotoxemic acute lung injury (ALI) rat model, berberine alleviated lung injury through different anti-inflammatory mechanisms; however, treatment effects on CX3CL1 expression and shedding remain to be examined. As these processes play important roles in promoting the binding of leukocytes to the endothelium, the CX3CL1/CX3CR1 axis and its related pathways may serve as potential targets for the clinical treatment of ALI. The anti-inflammatory effects of berberine were investigated in LPS-stimulated rats, human umbilical cord vein endothelial cells (HUVECs), and THP-1 monocytic cells. Cx3cl1 expression in rat pulmonary tissues was examined using immunohistochemistry. CX3CL1, CX3CR1, RELA, STAT3, and ADAM10 levels were examined using Western blotting. CX3CL1 and ADAM10 mRNA levels were examined using quantitative real-time polymerase chain reaction. Soluble fractalkine levels in LPS-stimulated rats and HUVECs were examined using the enzyme-linked immunosorbent assay. Berberine significantly mitigated the LPS-induced upregulation of fractalkine and soluble fractalkine in rats and cultured HUVECs. Berberine mitigated the LPS-induced activation of the NF-κB and STAT3 signaling pathways. In THP-1 cells, berberine mitigated the LPS-induced upregulation of CX3CR1. Furthermore, the membrane expression of ADAM10 in LPS-stimulated HUVECs was suppressed by the berberine treatment. Berberine dose-dependently inhibited the LPS-induced activation of the CX3CL1/CX3CR1 axis and fractalkine shedding through ADAM10. These findings reveal a novel molecular mechanism underlying the inhibitory effect of berberine on monocyte adherence to the endothelium during inflammation.

Ars moriendi: Proteases as sculptors of cellular suicide

The Ars moriendi, which translates to "The Art of Dying," encompasses two Latin texts that gave advice on how to die well and without fear according to the Christian precepts of the late Middle Ages. Given that ten to hundred billion cells die in our bodies every day, it is obvious that the concept of a well and orderly ("regulated") death is also paramount at the cellular level. In apoptosis, as the most well-studied form of regulated cell death, proteases of the caspase family are the central mediators. However, caspases are not the only proteases that act as sculptors of cellular suicide, and therefore, we here provide an overview of the impact of proteases in apoptosis and other forms of regulated cell death.

VIP plasma levels associate with survival in severe COVID-19 patients, correlating with protective effects in SARS-CoV-2-infected cells

Infection by SARS‐CoV‐2 may elicit uncontrolled and damaging inflammatory responses. Thus, it is critical to identify compounds able to inhibit virus replication and thwart the inflammatory reaction. Here, we show that the plasma levels of the immunoregulatory neuropeptide VIP are elevated in patients with severe COVID‐19, correlating with reduced inflammatory mediators and with survival on those patients. In vitro, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase‐activating polypeptide (PACAP), highly similar neuropeptides, decreased the SARS‐CoV‐2 RNA content in human monocytes and viral production in lung epithelial cells, also reducing cell death. Both neuropeptides inhibited the production of proinflammatory mediators in lung epithelial cells and in monocytes. VIP and PACAP prevented in monocytes the SARS‐CoV‐2‐induced activation of NF‐kB and SREBP1 and SREBP2, transcriptions factors involved in proinflammatory reactions and lipid metabolism, respectively. They also promoted CREB activation, a transcription factor with antiapoptotic activity and negative regulator of NF‐kB. Specific inhibition of NF‐kB and SREBP1/2 reproduced the anti‐inflammatory, antiviral, and cell death protection effects of VIP and PACAP. Our results support further clinical investigations of these neuropeptides against COVID‐19.

Adulthood asthma as a consequence of childhood adversity: a systematic review of epigenetically affected genes

There is an accumulating data that shows relation between childhood adversity and vulnerability to chronic diseases as well as epigenetic influences that in turn give rise to these diseases. Asthma is one of the chronic diseases that is influenced from genetic regulation of the inflammatory biomolecules and therefore the hypothesis in this research was childhood adversity might have caused epigenetic differentiation in the asthma-related genes in the population who had childhood trauma. To test this hypothesis, the literature was systematically reviewed to extract epigenetically modified gene data of the adults who had childhood adversity, and affected genes were further evaluated for their association with asthma. PRISMA guidelines were adopted and PubMed and Google Scholar were included in the searched databases, to evaluate epigenetic modifications in asthma-related genes of physically, emotionally or sexually abused children. After retrieving a total of 5245 articles, 36 of them were included in the study. Several genes and pathways that may contribute to pathogenesis of asthma development, increased inflammation, or response to asthma treatment were found epigenetically affected by childhood traumas. Childhood adversity, causing epigenetic changes in DNA, may lead to asthma development or influence the course of the disease and therefore should be taken into account for the prolonged health consequences.

Core genes involved in the regulation of acute lung injury and their association with COVID-19 and tumor progression: A bioinformatics and experimental study

Acute lung injury (ALI) is a specific form of lung damage caused by different infectious and non-infectious agents, including SARS-CoV-2, leading to severe respiratory and systemic inflammation. To gain deeper insight into the molecular mechanisms behind ALI and to identify core elements of the regulatory network associated with this pathology, key genes involved in the regulation of the acute lung inflammatory response (Il6, Ccl2, Cat, Serpine1, Eln, Timp1, Ptx3, Socs3) were revealed using comprehensive bioinformatics analysis of whole-genome microarray datasets, functional annotation of differentially expressed genes (DEGs), reconstruction of protein-protein interaction networks and text mining. The bioinformatics data were validated using a murine model of LPS-induced ALI; changes in the gene expression patterns were assessed during ALI progression and prevention by anti-inflammatory therapy with dexamethasone and the semisynthetic triterpenoid soloxolone methyl (SM), two agents with different mechanisms of action. Analysis showed that 7 of 8 revealed ALI-related genes were susceptible to LPS challenge (up-regulation: Il6, Ccl2, Cat, Serpine1, Eln, Timp1, Socs3; down-regulation: Cat) and their expression was reversed by the pre-treatment of mice with both anti-inflammatory agents. Furthermore, ALI-associated nodal genes were analysed with respect to SARS-CoV-2 infection and lung cancers. The overlap with DEGs identified in postmortem lung tissues from COVID-19 patients revealed genes (Saa1, Rsad2, Ifi44, Rtp4, Mmp8) that (a) showed a high degree centrality in the COVID-19-related regulatory network, (b) were up-regulated in murine lungs after LPS administration, and (c) were susceptible to anti-inflammatory therapy. Analysis of ALI-associated key genes using The Cancer Genome Atlas showed their correlation with poor survival in patients with lung neoplasias (Ptx3, Timp1, Serpine1, Plaur). Taken together, a number of key genes playing a core function in the regulation of lung inflammation were found, which can serve both as promising therapeutic targets and molecular markers to control lung ailments, including COVID-19-associated ALI.

Inhibitory monoclonal antibody targeting ADAM17 expressed on cancer cells

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A novel anti-ADAM17 monoclonal antibody, D8P1C1, has been developed.

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D8P1C1 inhibits the proteolysis of peptide substrates by ADAM17.

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D8P1C1 inhibits the proliferation of cancer cells and tumor growth inhibition in vivo.

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D8P1C1 preferentially recognizes ADAM17 on cancer cells.

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Negative stain EM analysis reveals that D8P1C1 binds to the ADAM17 protease domain.

ADAM17 is upregulated in many cancers and in turn activates signaling pathways, including EGFR/ErbB, as well as those underlying resistance to targeted anti-EGFR therapies. Due to its central role in oncogenic pathways and drug resistance mechanisms, specific and efficacious monoclonal antibodies against ADAM17 could be useful for a broad patient population with solid tumors. Hence, we describe here an inhibitory anti-ADAM17 monoclonal antibody, named D8P1C1, that preferentially recognizes ADAM17 on cancer cells. D8P1C1 inhibits the catalytic activity of ADAM17 in a fluorescence-based peptide cleavage assay, as well as the proliferation of a range of cancer cell lines, including breast, ovarian, glioma, colon and the lung adenocarcinoma. In mouse models of triple-negative breast cancer and ovarian cancer, treatment with the mAb results in 78% and 45% tumor growth inhibition, respectively. Negative staining electron microscopy analysis of the ADAM17 ectodomain in complex with D8P1C1 reveals that the mAb binds the ADAM17 protease domain, consistent with its ability to inhibit the ADAM17 catalytic activity. Collectively, our results demonstrate the therapeutic potential of the D8P1C1 mAb to treat solid tumors.

ADAM10 partially protects mice against influenza pneumonia by suppressing specific myeloid cell population

The influenza virus infection poses a serious health threat worldwide. Myeloid cells play pivotal roles in regulating innate and adaptive immune defense. A disintegrin and metalloproteinase (ADAM) family of proteins contributes to various immune responses; however, the role of a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) in influenza virus infection remains largely unknown. Herein, we investigated its role, focusing on myeloid cells, during influenza virus infection in mice. ADAM10 gene (Adam10)^flox/flox/Lyz2-Cre (Adam10^ΔLyz2) and control Adam10^flox/flox mice were intranasally infected with 200 plaque-forming units of influenza virus A/H1N1/PR8/34. Adam10^ΔLyz2 mice exhibited a significantly higher mortality rate, stronger lung inflammation, and a higher virus titer in the lungs than control mice. Macrophages and inflammatory cytokines, such as TNF-α, IL-1β, and CCL2, were increased in bronchoalveolar lavage fluid from Adam10^ΔLyz2 mice following infection. CD11b⁺Ly6G^-F4/80⁺ myeloid cells, which had an inflammatory monocyte/macrophage-like phenotype, were significantly increased in the lungs of Adam10^ΔLyz2 mice. Adoptive transfer experiments suggested that these cells likely contributed to the poorer prognosis in Adam10^ΔLyz2 mice. Seven days after infection, CD11b⁺Ly6G^-F4/80⁺ lung cells exhibited significantly higher arginase-1 expression levels in Adam10^ΔLyz2 mice than in control mice, whereas an arginase-1 inhibitor improved the prognosis of Adam10^ΔLyz2 mice. Enhanced granulocyte-macrophage colony-stimulating factor (GM-CSF)/GM-CSF receptor signaling likely contributed to this process. Collectively, these results indicate that myeloid ADAM10 protects against influenza virus pneumonia and may be a promising therapeutic target.

The pseudoprotease iRhom1 controls ectodomain shedding of membrane proteins in the nervous system

Proteolytic ectodomain shedding of membrane proteins is a fundamental mechanism to control the communication between cells and their environment. A key protease for membrane protein shedding is ADAM17, which requires a non-proteolytic subunit, either inactive Rhomboid 1 (iRhom1) or iRhom2 for its activity. While iRhom1 and iRhom2 are co-expressed in most tissues and appear to have largely redundant functions, the brain is an organ with predominant expression of iRhom1. Yet, little is known about the spatio-temporal expression of iRhom1 in mammalian brain and about its function in controlling membrane protein shedding in the nervous system. Here, we demonstrate that iRhom1 is expressed in mouse brain from the prenatal stage to adulthood with a peak in early postnatal development. In the adult mouse brain iRhom1 was widely expressed, including in cortex, hippocampus, olfactory bulb, and cerebellum. Proteomic analysis of the secretome of primary neurons using the hiSPECS method and of cerebrospinal fluid, obtained from iRhom1-deficient and control mice, identified several membrane proteins that require iRhom1 for their shedding in vitro or in vivo. One of these proteins was 'multiple-EGF-like-domains protein 10' (MEGF10), a phagocytic receptor in the brain that is linked to the removal of amyloid β and apoptotic neurons. MEGF10 was further validated as an ADAM17 substrate using ADAM17-deficient mouse embryonic fibroblasts. Taken together, this study discovers a role for iRhom1 in controlling membrane protein shedding in the mouse brain, establishes MEGF10 as an iRhom1-dependent ADAM17 substrate and demonstrates that iRhom1 is widely expressed in murine brain.

Posttranslational modifications by ADAM10 shape myeloid antigen-presenting cell homeostasis in the splenic marginal zone

The spleen contains phenotypically and functionally distinct conventional dendritic cell (cDC) subpopulations, termed cDC1 and cDC2, which each can be divided into several smaller and less well-characterized subsets. Despite advances in understanding the complexity of cDC ontogeny by transcriptional programming, the significance of posttranslational modifications in controlling tissue-specific cDC subset immunobiology remains elusive. Here, we identified the cell-surface-expressed A-disintegrin-and-metalloproteinase 10 (ADAM10) as an essential regulator of cDC1 and cDC2 homeostasis in the splenic marginal zone (MZ). Mice with a CD11c-specific deletion of ADAM10 (ADAM10^ΔCD11c) exhibited a complete loss of splenic ESAM^hi cDC2A because ADAM10 regulated the commitment, differentiation, and survival of these cells. The major pathways controlled by ADAM10 in ESAM^hi cDC2A are Notch, signaling pathways involved in cell proliferation and survival (e.g., mTOR, PI3K/AKT, and EIF2 signaling), and EBI2-mediated localization within the MZ. In addition, we discovered that ADAM10 is a molecular switch regulating cDC2 subset heterogeneity in the spleen, as the disappearance of ESAM^hi cDC2A in ADAM10^ΔCD11c mice was compensated for by the emergence of a Clec12a⁺ cDC2B subset closely resembling cDC2 generally found in peripheral lymph nodes. Moreover, in ADAM10^ΔCD11c mice, terminal differentiation of cDC1 was abrogated, resulting in severely reduced splenic Langerin⁺ cDC1 numbers. Next to the disturbed splenic cDC compartment, ADAM10 deficiency on CD11c⁺ cells led to an increase in marginal metallophilic macrophage (MMM) numbers. In conclusion, our data identify ADAM10 as a molecular hub on both cDC and MMM regulating their transcriptional programming, turnover, homeostasis, and ability to shape the anatomical niche of the MZ.

Endoglycan (PODXL2) is proteolytically processed by ADAM10 (a disintegrin and metalloprotease 10) and controls neurite branching in primary neurons

Cell adhesion is tightly controlled in multicellular organisms, for example, through proteolytic ectodomain shedding of the adhesion-mediating cell surface transmembrane proteins. In the brain, shedding of cell adhesion proteins is required for nervous system development and function, but the shedding of only a few adhesion proteins has been studied in detail in the mammalian brain. One such adhesion protein is the transmembrane protein endoglycan (PODXL2), which belongs to the CD34-family of highly glycosylated sialomucins. Here, we demonstrate that endoglycan is broadly expressed in the developing mouse brains and is proteolytically shed in vitro in mouse neurons and in vivo in mouse brains. Endoglycan shedding in primary neurons was mediated by the transmembrane protease a disintegrin and metalloprotease 10 (ADAM10), but not by its homolog ADAM17. Functionally, endoglycan deficiency reduced the branching of neurites extending from primary neurons in vitro, whereas deletion of ADAM10 had the opposite effect and increased neurite branching. Taken together, our study discovers a function for endoglycan in neurite branching, establishes endoglycan as an ADAM10 substrate and suggests that ADAM10 cleavage of endoglycan may contribute to neurite branching.

Implications of ADAM17 activation for hyperglycaemia, obesity and type 2 diabetes

In this review, we focus specifically on the role that the metalloproteinase, A Disintegrin and Metalloproteinase 17 [ADAM17] plays in the development and progression of the metabolic syndrome. There is a well-recognised link between the ADAM17 substrate tumour necrosis factor α (TNF-α) and obesity, inflammation and diabetes. In addition, knocking out ADAM17 in mice leads to an extremely lean phenotype. Importantly, ADAM17-deficient mice exhibit one of the most pronounced examples of hypermetabolism in rodents to date. It is vital to further understand the mechanistic role that ADAM17 plays in the metabolic syndrome. Such studies will demonstrate that ADAM17 is a valuable therapeutic target to treat obesity and diabetes.

Silencing a disintegrin and metalloproteinase‑33 attenuates the proliferation of vascular smooth muscle cells via PI3K/AKT pathway: Implications in the pathogenesis of airway vascular remodeling

Accumulating evidence suggests that pulmonary expression of a disintegrin and metalloproteinase-33 (ADAM33) serves a key role in the pathogenesis of airway remodeling-related diseases, including asthma. Airway vascular proliferation has been recognized as a key feature of airway remodeling. Our previous study showed that ADAM33 is constitutively expressed in airway vascular smooth muscle cells in patients with asthma, suggesting a potential role of ADAM33 in regulating airway vascular remodeling. Using in vitro human aortic smooth muscle cells (HASMCs) and lentiviral vector carrying short hairpin RNA for ADAM33, the present study aimed to evaluate the influence of ADAM33 silencing on the proliferation and apoptosis of HASMCs and the underlying molecular pathways. Cellular proliferation was observed using the Cell Counting Kit-8 method. Cellular apoptosis was evaluated with Annexin V-PE/7-AAD staining and flow cytometry. Reverse transcription-quantitative PCR and western blotting were used to evaluate the changes in mRNA and protein levels of involved signaling molecules. It was found that silencing of ADAM33 expression in HASMCs significantly inhibited proliferation, but induced the apoptosis of HASMCs. These changes were accompanied by inhibition of the PI3K/AKT/ERK pathway and Bcl-2, but an increase in Bax expression. These results suggested that constitutive expression of ADAM33 may be important to maintain a proliferative phenotype in HASMCs. The influences of ADAM33 on proliferation and apoptosis of HASMCs may involve regulation of PI3K/AKT/ERK and Bax/Bcl-2 pathways. These findings suggested an important role of ADAM33 in airway vascular remodeling and potential therapeutic significance of ADAM33 inhibition in airway remodeling-related diseases.

A disintegrin and metalloproteinase domain-15 deficiency leads to exaggerated cigarette smoke-induced chronic obstructive pulmonary disease (COPD)-like disease in mice

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by cells implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), but its contributions to COPD are unknown. To address this gap, ADAM15 levels were measured in samples from cigarette smoke (CS)-versus air-exposed wild-type (WT) mice. CS-induced COPD-like disease was compared in CS-exposed WT, Adam15^-/-, and Adam15 bone marrow chimeric mice. CS exposure increased Adam15 expression in lung macrophages and CD8⁺ T cells and to a lesser extent in airway epithelial cells in WT mice. CS-exposed Adam15^-/- mice had greater emphysema, small airway fibrosis, and lung inflammation (macrophages and CD8⁺ T cells) than WT mice. Adam15 bone marrow chimera studies revealed that Adam15 deficiency in leukocytes led to exaggerated pulmonary inflammation and COPD-like disease in mice. Adam15 deficiency in CD8⁺ T cells was required for the exaggerated pulmonary inflammation and COPD-like disease in CS-exposed Adam15^-/- mice (as assessed by genetically deleting CD8⁺ T cells in Adam15^-/- mice). Adam15 deficiency increased pulmonary inflammation by rendering CD8⁺ T cells and macrophages resistant to CS-induced activation of the mitochondrial apoptosis pathway by preserving mTOR signaling and intracellular Mcl-1 levels in these cells. These results strongly link ADAM15 deficiency to the pathogenesis of COPD.

ACE2 expression is elevated in airway epithelial cells from older and male healthy individuals but reduced in asthma

BACKGROUND AND OBJECTIVE

COVID-19 is complicated by acute lung injury, and death in some individuals. It is caused by SARS-CoV-2 that requires the ACE2 receptor and serine proteases to enter AEC. We determined what factors are associated with ACE2 expression particularly in patients with asthma and COPD.

METHODS

We obtained lower AEC from 145 people from two independent cohorts, aged 2-89 years, Newcastle (n = 115) and Perth (n = 30), Australia. The Newcastle cohort was enriched with people with asthma (n = 37) and COPD (n = 38). Gene expression for ACE2 and other genes potentially associated with SARS-CoV-2 cell entry was assessed by qPCR, and protein expression was confirmed with immunohistochemistry on endobronchial biopsies and cultured AEC.

RESULTS

Increased gene expression of ACE2 was associated with older age (P = 0.03) and male sex (P = 0.03), but not with pack-years smoked. When we compared gene expression between adults with asthma, COPD and healthy controls, mean ACE2 expression was lower in asthma patients (P = 0.01). Gene expression of furin, a protease that facilitates viral endocytosis, was also lower in patients with asthma (P = 0.02), while ADAM-17, a disintegrin that cleaves ACE2 from the surface, was increased (P = 0.02). ACE2 protein expression was also reduced in endobronchial biopsies from asthma patients.

CONCLUSION

Increased ACE2 expression occurs in older people and males. Asthma patients have reduced expression. Altered ACE2 expression in the lower airway may be an important factor in virus tropism and may in part explain susceptibility factors and why asthma patients are not over-represented in those with COVID-19 complications.

The metalloproteinase ADAM10 requires its activity to sustain surface expression

The metalloproteinase ADAM10 critically contributes to development, inflammation, and cancer and can be controlled by endogenous or synthetic inhibitors. Here, we demonstrate for the first time that loss of proteolytic activity of ADAM10 by either inhibition or loss of function mutations induces removal of the protease from the cell surface and the whole cell. This process is temperature dependent, restricted to mature ADAM10, and associated with an increased internalization, lysosomal degradation, and release of mature ADAM10 in extracellular vesicles. Recovery from this depletion requires de novo synthesis. Functionally, this is reflected by loss and recovery of ADAM10 substrate shedding. Finally, ADAM10 inhibition in mice reduces systemic ADAM10 levels in different tissues. Thus, ADAM10 activity is critically required for its surface expression in vitro and in vivo. These findings are crucial for development of therapeutic ADAM10 inhibition strategies and may showcase a novel, physiologically relevant mechanism of protease removal due to activity loss.

Relationship Between Proteinase with a Disintegrin and a Metalloproteinase Domain-9 (ADAM9), Inflammation, Airway Remodeling, and Emphysema in COPD Patients

Background and Objective

The link between ADAM9 and airway remodeling and emphysema severity in COPD patients has not been elucidated. Here, we investigated the relationship between ADAM9 levels in sputum and airway epithelium and the clinical characteristics of COPD patients.

Methods

A sputum cohort and a lung tissue cohort were included in the study. Pulmonary function and computed tomography data were analyzed in COPD patients, non-COPD smokers, and non-smokers. Soluble ADAM9 and interleukin 8 (IL-8) levels in sputum supernatants as well as surface ADAM9 expression in airway epithelium were detected. Emphysema scores were calculated by the percentage of low attenuation area (%LAA-950), and airway remodeling was measured via airway thickening and loss of airway counts.

Results

Both soluble ADAM9 levels in sputum and relative surface ADAM9 expression in airway epithelium were increased in COPD patients. Sputum ADAM9 levels were negatively correlated with forced expiratory volume in 1 s of predicted (FEV1% of predicted) and positively correlated with sputum IL-8 levels, but not with CT measured emphysema nor airway remodeling. The ADAM9 expression in airway epithelia was positively correlated with %LAA-950 and airway wall thickening parameters (wall area percentage, WA%; the square root of the wall area in a standard airway with a 10 mm internal perimeter, Pi-10), while negatively correlated with airway counts derived from the 4th to 9th bronchial generations.

Conclusion

Airway ADAM9 levels in sputum and airway epithelium were both elevated in COPD patients compared to non-COPD controls. Sputum ADAM9 seemed to be associated with inflammatory responses in COPD, while epithelial ADAM9 was more correlated with emphysema and airway remodeling.

A Disintegrin and Metalloproteinase-Control Elements in Infectious Diseases

Despite recent advances in treatment strategies, infectious diseases are still under the leading causes of death worldwide. Although the activation of the inflammatory cascade is one prerequisite of defense, persistent and exuberant immune response, however, may lead to chronicity of inflammation predisposing to a temporal or permanent tissue damage not only of the site of infection but also among different body organs. The initial response to invading pathogens is mediated by the recognition through various pattern-recognition receptors along with cellular engulfment resulting in a coordinated release of soluble effector molecules and cytokines aiming to terminate the external stimuli. Members of the ‘a disintegrin and metalloproteinase’ (ADAM) family have the capability to proteolytically cleave transmembrane molecules close to the plasma membrane, a process called ectodomain shedding. In fact, in infectious diseases dysregulation of numerous ADAM substrates such as junction molecules (e.g., E-cadherin, VE-cadherin, JAM-A), adhesion molecules (e.g., ICAM-1, VCAM-1, L-selectin), and chemokines and cytokines (e.g., CXCL16, TNF-α) has been observed. The alpha-cleavage by ADAM proteases represents a rate limiting step for downstream regulated intramembrane proteolysis (RIPing) of several substrates, which influence cellular differentiation, cell signaling pathways and immune modulation. Both the substrates mentioned above and RIPing crucially contribute to a systematic damage in cardiovascular, endocrine, and/or gastrointestinal systems. This review will summarize the current knowledge of ADAM function and the subsequent RIPing in infectious diseases (e.g., pathogen recognition and clearance) and discuss the potential long-term effect on pathophysiological changes such as cardiovascular diseases.

An Overview of ADAM9: Structure, Activation, and Regulation in Human Diseases

ADAM9 (A disintegrin and a metalloprotease 9) is a membrane-anchored protein that participates in a variety of physiological functions, primarily through the disintegrin domain for adhesion and the metalloprotease domain for ectodomain shedding of a wide variety of cell surface proteins. ADAM9 influences the developmental process, inflammation, and degenerative diseases. Recently, increasing evidence has shown that ADAM9 plays an important role in tumor biology. Overexpression of ADAM9 has been found in several cancer types and is correlated with tumor aggressiveness and poor prognosis. In addition, through either proteolytic or non-proteolytic pathways, ADAM9 promotes tumor progression, therapeutic resistance, and metastasis of cancers. Therefore, comprehensively understanding the mechanism of ADAM9 is crucial for the development of therapeutic anti-cancer strategies. In this review, we summarize the current understanding of ADAM9 in biological function, pathophysiological diseases, and various cancers. Recent advances in therapeutic strategies using ADAM9-related pathways are presented as well.

The iRhom2/ADAM17 Axis Attenuates Bacterial Uptake by Phagocytes in a Cell Autonomous Manner

Uptake of bacteria by phagocytes is a crucial step in innate immune defence. Members of the disintegrin and metalloproteinase (ADAM) family critically control the immune response by limited proteolysis of surface expressed mediator molecules. Here, we investigated the significance of ADAM17 and its regulatory adapter molecule iRhom2 for bacterial uptake by phagocytes. Inhibition of metalloproteinase activity led to increased phagocytosis of pHrodo labelled Gram-negative and -positive bacteria (E. coli and S. aureus, respectively) by human and murine monocytic cell lines or primary phagocytes. Bone marrow-derived macrophages showed enhanced uptake of heat-inactivated and living E. coli when they lacked either ADAM17 or iRhom2 but not upon ADAM10-deficiency. In monocytic THP-1 cells, corresponding short hairpin RNA (shRNA)-mediated knockdown confirmed that ADAM17, but not ADAM10, promoted phagocytosis of E. coli. The augmented bacterial uptake occurred in a cell autonomous manner and was accompanied by increased release of the chemokine CXCL8, less TNFα release and only minimal changes in the surface expression of the receptors TNFR1, TLR6 and CD36. Inhibition experiments indicated that the enhanced bacterial phagocytosis after ADAM17 knockdown was partially dependent on TNFα-activity but not on CXCL8. This novel role of ADAM17 in bacterial uptake needs to be considered in the development of ADAM17 inhibitors as therapeutics.

ADAM15 expression is increased in lung CD8+ T cells, macrophages, and bronchial epithelial cells in patients with COPD and is inversely related to airflow obstruction

BACKGROUND

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by activated leukocytes, and fibroblasts in vitro. Whether ADAM15 expression is increased in the lungs of COPD patients is not known.

METHODS

ADAM15 gene expression and/or protein levels were measured in whole lung and bronchoalveolar lavage (BAL) macrophage samples obtained from COPD patients, smokers, and non-smokers. Soluble ADAM15 protein levels were measured in BAL fluid (BALF) and plasma samples from COPD patients and controls. Cells expressing ADAM15 in the lungs were identified using immunostaining. Staining for ADAM15 in different cells in the lungs was related to forced expiratory volume in 1 s (FEV1), ratio of FEV1 to forced vital capacity (FEV1/FVC), and pack-years of smoking history.

RESULTS

ADAM15 gene expression and/or protein levels were increased in alveolar macrophages and whole lung samples from COPD patients versus smokers and non-smokers. Soluble ADAM15 protein levels were similar in BALF and plasma samples from COPD patients and controls. ADAM15 immunostaining was increased in macrophages, CD8+ T cells, epithelial cells, and airway α-smooth muscle (α-SMA)-positive cells in the lungs of COPD patients. ADAM15 immunostaining in macrophages, CD8+ T cells and bronchial (but not alveolar) epithelial cells was related inversely to FEV1 and FEV1/FVC, but not to pack-years of smoking history. ADAM15 staining levels in airway α-SMA-positive cells was directly related to FEV1/FVC. Over-expressing ADAM15 in THP-1 cells reduced their release of matrix metalloproteinases and CCL2.

CONCLUSIONS

These results link increased ADAM15 expression especially in lung leukocytes and bronchial epithelial cells to the pathogenesis of COPD.

Novel Approaches and Challenges of Discovery of Exosite Modulators of a Disintegrin and Metalloprotease 10

A disintegrin and metaproteinase 10 is an important target for multiple therapeutic areas, however, despite drug discovery efforts by both industry and academia no compounds have reached the clinic so far. The lack of enzyme and substrate selectivity of developmental drugs is believed to be a main obstacle to the success. In this review, we will focus on novel approaches and associated challenges in discovery of ADAM10 selective modulators that can overcome shortcomings of previous generations of compounds and be translated into the clinic.

Targeting ADAM10 in Cancer and Autoimmunity

Generating inhibitors for A Disintegrin And Metalloproteinase 10 (ADAM10), a zinc-dependent protease, was heavily invested in by the pharmaceutical industry starting over 20 years ago. There has been much enthusiasm in basic research for these inhibitors, with a multitude of studies generating significant data, yet the clinical trials have not replicated the same results. ADAM10 is ubiquitously expressed and cleaves many important substrates such as Notch, PD-L1, EGFR/HER ligands, ICOS-L, TACI, and the "stress related molecules" MIC-A, MIC-B and ULBPs. This review goes through the most recent pre-clinical data with inhibitors as well as clinical data supporting the use of ADAM10 inhibitor use in cancer and autoimmunity. It additionally addresses how ADAM10 inhibitor therapy can be improved and if inhibitor therapy can be paired with other drug treatments to maximize effectiveness in various disease states. Finally, it examines the ADAM10 substrates that are important to each disease state and if any of these substrates or ADAM10 itself is a potential biomarker for disease.

miR-21-3p regulates AGE/RAGE signalling and improves diabetic atherosclerosis

To explore the effects of miR-21-3p on diabetic atherosclerosis. Using enzyme-linked immunosorbent assay (ELISA), we also detected the levels of soluble receptor for advanced glycation endproducts RAGE (sRAGE) in the cellular supernatant of vascular endothelial cells after transfecting them with adenovirus vector having miR-21-3p mimic or inhibitor. We found decrease in the expression levels of miR-21-3p in vascular endothelial cells (VECs) induced by high-concentration glucose. We also observed that the introduction of miR-21-3p mimic significantly increased the expression of ADAM10 in the VECs. Similarly, significantly higher levels of sRAGE were found in the cultured supernatant after administration of miR-21-3p mimic in human vein endothelial cells. The production of reactive oxygen species and expression of inflammatory cytokines in VECs induced by LPS and high-concentration glucose were significantly decreased after administration of miR-21-3p. in vivo studies revealed that intravenous injection of miR-21-3p at regular intervals would reduce the area of atherosclerotic lesion and elevate the serum levels of sRAGE in atherosclerotic diabetic mice. miR-21-3p may be beneficial in diabetic atherosclerosis by promoting the cleaved form of sRAGE and inhibition of RAGE/NADPH oxidase signalling depending on the increased expression of ADAM10. SIGNIFICANCE OF THE STUDY: We identified a novel microRNA, miR-21-3p, which is characteristically at elevated levels in serum derived from diabetic patients and responsible for target degradation of ADAM10 mRNA. Further, we show that miR-21-3p aggravates the atherosclerotic lesion via dysfunction of the ectodomain shedding of molecular binding RAGE in the diabetic atherosclerotic mice.

Necroptosis, ADAM proteases and intestinal (dys)function

Recently, an unexpected connection between necroptosis and members of the a disintegrin and metalloproteinase (ADAM) protease family has been reported. Necroptosis represents an important cell death routine which helps to protect from viral, bacterial, fungal and parasitic infections, maintains adult T cell homeostasis and contributes to the elimination of potentially defective organisms before parturition. Equally important for organismal homeostasis, ADAM proteases control cellular processes such as development and differentiation, immune responses or tissue regeneration. Notably, necroptosis as well as ADAM proteases have been implicated in the control of inflammatory responses in the intestine. In this review, we therefore provide an overview of the physiology and pathophysiology of necroptosis, ADAM proteases and intestinal (dys)function, discuss the contribution of necroptosis and ADAMs to intestinal (dys)function, and review the current knowledge on the role of ADAMs in necroptotic signaling.

ADAMs and ADAMTSs☆

Proteolysis has emerged as a key post-translational regulator of the function of molecules on the cell surface and in the extracellular milieu. In principle, proteolysis can activate or inactivate a substrate, or can change its functional properties. ADAMs (a disintegrin and metalloprotease) and ADAMTS (a disintegrin-like and metalloprotease domain with thrombospondin type 1 repeats) proteases are related members of a superfamily of metallo-endopeptidases that also includes MMPs and astacins. ADAMs are integral membrane proteins that typically cleave other membrane anchored proteins, whereas ADAMTS proteases lack a membrane anchor, and process both cell-surface and secreted molecules, the latter mostly extracellular matrix (ECM) components. ADAMs are implicated in fertilization, neurogenesis, in regulating the function of ligands for the EGF-receptor, and in the release of proteins such as the pro-inflammatory cytokine TNFα from the plasma membrane. ADAMTS proteases have key roles in embryonic development, including lung development, the molecular maturation of von Willebrand factor and procollagen as well as organization of fibrillin microfibrils in ECM, and are implicated in the pathogenesis of diverse lung and airway disorders. Here, we provide a general overview of the biochemical properties and physiological functions of ADAMs and ADAMTS proteases and describe their relevance to lung and airway disorders.

miR-23b Negatively Regulates Sepsis-Induced Inflammatory Responses by Targeting ADAM10 in Human THP-1 Monocytes

Background

Previous studies have demonstrated pivotal roles of disintegrin and metalloproteinase 10 (ADAM10) in the pathogenesis of sepsis. MicroRNA- (miR-) 23b has emerged as an anti-inflammatory factor that prevents multiple autoimmune diseases. However, the underlying mechanisms of miR-23b in the regulation of ADAM10 and sepsis remain uncharacterized.

Methods

The expression levels of ADAM10 and miR-23b were detected by quantitative RT-PCR and western blot analysis. Cytokine production and THP-1 cell apoptosis were measured by enzyme-linked immunosorbent and annexin V apoptosis assays. Bioinformatics analyses and qRT-PCR, western blot, and luciferase reporter assays were performed to identify ADAM10 as the target gene of miR-23b.

Results

miR-23b expression was downregulated in the peripheral blood mononuclear cells of sepsis patients and LPS-induced THP-1 cells and was negatively correlated with the expression of ADAM10 and inflammatory cytokines. miR-23b regulated ADAM10 expression by directly binding to the 3′-UTR of ADAM10 mRNA. The overexpression of miR-23b alleviated the LPS-stimulated production of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and apoptosis by targeting ADAM10 in THP-1 cells. The inhibitor or knockdown of ADAM10 elicited effects similar to those of miR-23b on THP-1 cells upon LPS stimulation.

Conclusions

The present study demonstrated that miR-23b negatively regulated LPS-induced inflammatory responses by targeting ADAM10. The molecular regulatory mechanism of miR-23b in ADAM10 expression and sepsis-induced inflammatory consequences may provide potential therapeutic targets for sepsis.

ADAM Metalloproteinases as Potential Drug Targets

The ADAMs, together with ADAMTSs and snake venom metalloproteases (SVMPs), are members of the Adamalysin family. Differences in structural organization, functions and localization are known and their domains, catalytic or non-catalytic, show key roles in the substrate recognition and protease activity. Some ADAMs, as membrane-bound enzymes, show sheddase activity. Sheddases are key to modulation of functional proteins such as the tumor necrosis factor, growth factors, cytokines and their receptors, adhesion proteins, signaling molecules and stress molecules involved in immunity. These activities take part in the regulation of several physiological and pathological processes including inflammation, tumor growth, metastatic progression and infectious diseases. On these bases, some ADAMs are currently investigated as drug targets to develop new alternative therapies in many fields of medicine. This review will be focused on these aspects.

Feedback loop in miR-449b-3p/ADAM17/NF-κB promotes metastasis in nasopharyngeal carcinoma

An emerging body of evidence has promoted the understanding of the role of microRNAs (miRNAs) in tumorigenesis and progression, but the mediating function of miRNAs in nasopharyngeal carcinoma (NPC) development remains poorly elucidated. In this study, miR‐449b‐3p was downregulated in NPC specimens (P < .001) and cells (P < .05). Cytological and animal experiments provided evidence that miR‐449b‐3p inhibited NPC metastasis in vitro and in vivo. Disintegrin and metalloproteinase 17 (ADAM17) was revealed as a direct target of miR‐449b‐3p. Rescue experiments suggested that the downregulation of ADAM17 in the miR‐449b‐3p knockdown cells partially reversed the inhibition of cell invasion and migration. Luciferase reporter assay, chromatin immunoprecipitation assay, and Western blot analysis showed that ADAM17 could suppress the promoter activity and expression of miR‐449b‐3p by inducing NF‐κB transcriptional activity. In conclusion, our study provided new insights into the underlying mechanism of the invasion and metastasis of NPC. The novel miR‐449b‐3p/ADAM17/NF‐κB feedback loop could be a target for the clinical treatment of NPC.

Activated Leukocyte Cell Adhesion Molecule Stimulates the T-Cell Response in Allergic Asthma

RATIONALE

The activated leukocyte cell adhesion molecule (ALCAM) is a cluster of differentiation 6 ligand that is important for stabilizing the immunological synapse and inducing T-cell activation and proliferation.

OBJECTIVES

In this study, we investigated the role of ALCAM in the development of inflammation in allergic asthma.

METHODS

An ovalbumin (OVA)-induced allergic asthma model was established in wild-type (WT) and ALCAM-deficient (ALCAM^-/-) mice. T-cell proliferation was evaluated in cocultures with dendritic cells (DCs). Bone marrow-derived dendritic cells (BMDCs) from WT and ALCAM^-/- mice were cultured and adoptively transferred to OT-II mice for either OVA sensitization or challenge. An anti-ALCAM antibody was administered to assess its therapeutic potential. ALCAM concentrations in the sputum and serum of children with asthma were quantified by ELISA.

MEASUREMENTS AND MAIN RESULTS

Inflammatory responses were lower in ALCAM^-/- mice than in WT mice, and T cells cocultured with DCs from ALCAM^-/- mice showed reduced proliferation relative to those cocultured with DCs from WT mice. A decreased inflammatory response was observed upon adoptive transfer of BMDCs from ALCAM^-/- mice as compared with that observed after transfer of BMDCs from WT mice. In addition, anti-ALCAM antibody-treated mice showed a reduced inflammatory response, and sputum and serum ALCAM concentrations were higher in children with asthma than in control subjects.

CONCLUSIONS

ALCAM contributes to OVA-induced allergic asthma by stimulating T-cell activation and proliferation, suggesting it as a potential therapeutic target for allergic asthma.

Functions of 'A disintegrin and metalloproteases (ADAMs)' in the mammalian nervous system

'A disintegrin and metalloproteases' (ADAMs) are a family of transmembrane proteins with diverse functions in multicellular organisms. About half of the ADAMs are active metalloproteases and cleave numerous cell surface proteins, including growth factors, receptors, cytokines and cell adhesion proteins. The other ADAMs have no catalytic activity and function as adhesion proteins or receptors. Some ADAMs are ubiquitously expressed, others are expressed tissue specifically. This review highlights functions of ADAMs in the mammalian nervous system, including their links to diseases. The non-proteolytic ADAM11, ADAM22 and ADAM23 have key functions in neural development, myelination and synaptic transmission and are linked to epilepsy. Among the proteolytic ADAMs, ADAM10 is the best characterized one due to its substrates Notch and amyloid precursor protein, where cleavage is required for nervous system development or linked to Alzheimer's disease (AD), respectively. Recent work demonstrates that ADAM10 has additional substrates and functions in the nervous system and its substrate selectivity may be regulated by tetraspanins. New roles for other proteolytic ADAMs in the nervous system are also emerging. For example, ADAM8 and ADAM17 are involved in neuroinflammation. ADAM17 additionally regulates neurite outgrowth and myelination and its activity is controlled by iRhoms. ADAM19 and ADAM21 function in regenerative processes upon neuronal injury. Several ADAMs, including ADAM9, ADAM10, ADAM15 and ADAM30, are potential drug targets for AD. Taken together, this review summarizes recent progress concerning substrates and functions of ADAMs in the nervous system and their use as drug targets for neurological and psychiatric diseases.