The shedding protease ADAM17: Physiology and pathophysiology

The late-onset Alzheimer's disease risk factor RHBDF2 is a modifier of microglial TREM2 proteolysis

The cell surface receptor TREM2 is a key genetic risk factor and drug target in Alzheimer's disease (AD). In the brain, TREM2 is expressed in microglia, where it undergoes proteolytic cleavage, linked to AD risk, but the responsible protease in microglia is still unknown. Another microglial-expressed AD risk factor is catalytically inactive rhomboid 2 (iRhom2, RHBDF2), which binds to and acts as a non-catalytic subunit of the metalloprotease ADAM17. A potential role in TREM2 proteolysis is not yet known. Using microglial-like BV2 cells, bone marrow-derived macrophages, and primary murine microglia, we identify iRhom2 as a modifier of ADAM17-mediated TREM2 shedding. Loss of iRhom2 increased TREM2 in cell lysates and at the cell surface and enhanced TREM2 signaling and microglial phagocytosis of the amyloid β-peptide (Aβ). This study establishes ADAM17 as a physiological TREM2 protease in microglia and suggests iRhom2 as a potential drug target for modulating TREM2 proteolysis in AD.

Prolyl hydroxylase inhibitor desidustat improves stroke outcomes via enhancing efferocytosis in mice with chronic kidney disease

Patients with chronic kidney disease (CKD) are at a significantly increased risk of stroke and experience worse stroke outcomes and higher mortality. CKD exacerbates stroke risk and severity through a complex interplay of systemic inflammation, oxidative stress, and impaired clearance of uremic toxins, leading to neuroinflammation and microglial activation. Current acute ischemic stroke treatments, while effective in the general population, do not adequately address CKD-specific mechanisms, limiting their efficacy in this high-risk population. Prolyl hydroxylase domain (PHD) inhibitors have shown promise in treating anemia associated with CKD and may offer cerebroprotective benefits. However, the effects of PHD2 inhibition on long-term sensorimotor outcomes and the underlying mechanisms in mice with CKD remain largely unknown. Here, we investigated the impact of CKD on stroke severity and assessed the therapeutic potential of desidustat, a PHD inhibitor, in improving stroke outcomes. Using an adenine-induced CKD mouse model, we demonstrated that CKD exacerbated stroke-induced long-term sensorimotor deficits, increased neuroinflammation, and impaired microglial efferocytosis via dysregulation of the ADAM17-MerTK axis. Desidustat treatment in mice with CKD significantly improved long-term sensorimotor functional outcomes and reduced post-stroke neuroinflammation while enhancing microglial efferocytosis by reducing ADAM17 and enhancing microglial MerTK expression. In vitro studies using human-induced microglia-like cells further confirmed the ability of desidustat to enhance efferocytosis of apoptotic neurons by reducing the cleavage of MerTK. These findings suggest that desidustat may serve as a novel therapeutic strategy for improving stroke outcomes in patients with CKD, a population at high risk for stroke and poor functional recovery.

Therapeutic Potential of Qilianxiaopi Formula: Targeting ADAM17-Mediated Chronic Inflammation in Atrophic Gastritis

Background: Gastric cancer (GC) is a leading cause of mortality worldwide, particularly in China. Chronic atrophic gastritis (CAG) and intestinal metaplasia (IM) are recognized as precancerous conditions contributing to GC development. Qilianxiaopi formula (QLXP), a traditional Chinese medicine (TCM), has demonstrated significant therapeutic effects on CAG and IM; however, its underlying mechanisms remain poorly understood. Methods: This study utilized chromatography-mass spectrometry to identify the major compounds in QLXP. Network pharmacology was used to predict the associated targets of these components. Thermal proteome profiling (TPP) pinpointed the potential binding proteins of QLXP, which were validated by bioinformatic analyses. Bio-layer interferometry (BLI) was used to analyze the interactions between QLXP and its key target proteins, thereby determining their binding components. Molecular docking predicted the binding modes between the components and proteins. Results: ADAM17 was identified as a key binding protein for QLXP. Further investigation revealed that QLXP inhibits the enzymatic activity of ADAM17, thereby reducing the secretion of the pro-inflammatory cytokine TNF-α, contributing to the anti-inflammatory properties of QLXP. BLI confirmed direct and reversible binding interactions between QLXP and ADAM17. Narirutin, isolated from the ADAM17 binding fraction, displayed the highest affinity for QLXP. Conclusions: This study highlights ADAM17 as a key molecular target of QLXP and narirutin as its principal binding component. The integrated approach combining chromatography-mass spectrometry, network pharmacology, TPP, BLI, and molecular docking provides a robust framework for elucidating the mechanisms of action of TCM.

Progress of ADAM17 in Fibrosis-Related Diseases

Fibrosis leads to structural damage and functional decline and is characterized by an accumulation of fibrous connective tissue and a reduction in parenchymal cells. Because of its extremely poor prognosis, organ fibrosis poses a significant economic burden. In order to prevent and treat fibrosis more effectively, potential mechanisms need to be investigated. A disintegrin and metalloprotease 17 (ADAM17) is a membrane-bound protein. It regulates intracellular signaling and membrane protein degradation. Fibrosis mediated by ADAM17 has been identified as an important contributor, although the specific relationship between its multiple regulatory functions and the pathogenesis is unclear. This article describes ADAM17 activation, function, and regulation, as well as the role of ADAM17 mediated fibrosis injury in kidney, liver, heart, lung, skin, endometrium, and retina. To develop new therapeutic approaches based on ADAM17 related signal pathways.

Novel insights into the central protective role of ACE2 in diabetic cardiomyopathy: from underlying signaling pathways to therapeutic perspectives

Diabetic cardiomyopathy (DCM) is a cardiac complication specific to individuals with diabetes. It is defined as abnormalities of myocardial structure and function in diabetic patients who do not exhibit any obvious coronary artery disease, hypertensive heart disease, valvular heart disease, or inherited cardiomyopathy. A significant cardiovascular protective factor identified recently is angiotensin-converting enzyme 2 (ACE2), which is a rising star in the renin angiotensin system (RAS) and is responsible for the onset and progression of DCM. Nonetheless, there is not a comprehensive review outlining ACE2's effect on DCM. From the perspective of the pathogenesis of DCM, this review summarizes the myocardial protective role of ACE2 in the aspects of alleviating myocardial structure and dysfunction, correcting energy metabolism disorders, and restoring vascular function. Concurrently, we propose the connections between ACE2 and underlying signaling pathways, including ADAM17, Apelin/APJ, and Nrf2. Additionally, we highlight ACE2-related pharmaceutical treatment options and clinical application prospects for preventing and managing DCM. Further and underlying research is extensively required to completely comprehend the principal pathophysiological mechanism of DCM and the distinctive function of ACE2, switching experimental findings into clinical practice and identifying efficient therapeutic approaches.

Proinflammatory microglial activation impairs in vitro cortical tissue repair via zinc-dependent ADAM17 cleavage of the CSF-1 receptor

Infection and subsequent inflammatory processes negatively impact prognosis in individuals with traumatic brain injury (TBI). Tissue repair following TBI is tightly regulated by microglia, promoting or, importantly, preventing astrocyte-mediated repair processes, depending on the activation state of the neuroimmune cells. This study investigated the poorly understood mechanism linking proinflammatory microglia activation and astrocyte-mediated tissue repair using an in vitro mechanical injury model in mixed cortical cultures of rat neurons and glia. We hypothesized that proinflammatory activation disrupts the microglial response to colony-stimulating factor 1 (CSF-1), which stimulates microglia migration and proliferation, both essential for astrocyte-mediated tissue repair. Following mechanical damage, cultures were treated with lipopolysaccharide (LPS) and interferon-gamma (IFNγ) to induce a proinflammatory state. Immunocytochemical and biochemical analyses were used to evaluate glial repair. Proinflammatory activation dramatically impeded wound closure, reducing microglial levels via upregulation of the zinc-dependent disintegrin and metalloprotease 17 (ADAM17), leading to the cleavage of the CSF-1 receptor (CSF-1R). Indeed, pharmacological inhibition of ADAM17 effectively promoted wound closure during inflammation. Moreover, zinc chelation prevented ADAM17-mediated cleavage of CSF-1R and induced the release of trophic factors, dramatically improving tissue recovery. Our findings strongly identify ADAM17 as a primary regulator of CSF-1R-mediated signaling and establish a mechanism defining the association between pro-inflammatory microglial activation and tissue repair following injury.

JG26 attenuates ADAM17 metalloproteinase-mediated ACE2 receptor processing and SARS-CoV-2 infection in vitro

BACKGROUND

ADAM17 is a metalloprotease implicated in the proteolysis of angiotensin-converting enzyme 2 (ACE2), known to play a critical role in the entry and spread of SARS-CoV-2. In this context, ADAM17 results as a potential novel target for controlling SARS-CoV-2 infection.

METHODS

In this study, we investigated the impact on ACE2 surface expression and the antiviral efficacy against SARS-CoV-2 infection of the selective ADAM17 inhibitor JG26 and its dimeric (compound 1) and glycoconjugate (compound 2) derivatives using Calu-3 human lung cells.

RESULTS

None of the compounds exhibited cytotoxic effects on Calu-3 cells up to a concentration of 25 µM. Treatment with JG26 resulted in partial inhibition of both ACE2 receptor shedding and SARS-CoV-2 infection, followed by compound 1.

CONCLUSION

JG26, an ADAM17 inhibitor, demonstrated promising antiviral activity against SARS-CoV-2 infection, likely attributed to reduced sACE2 availability, thus limiting viral dissemination.

Involvement of ADAM17-Klotho Crosstalk in High Glucose-Induced Alterations of Podocyte Function

Microalbuminuria is the earliest clinical abnormality in diabetic kidney disease. High glucose (HG) concentrations are associated with the induction of oxidative stress in podocytes, leading to disruption of the glomerular filtration barrier. Our recent study revealed a significant decrease in the membrane-bound fraction of Klotho in podocytes that were cultured under HG conditions. Given that disintegrin and metalloproteinase 17 (ADAM17) is responsible for the shedding of Klotho from the cell membrane, the present study investigated the impact of HG on the interplay between ADAM17 and Klotho in human podocytes. We demonstrated that ADAM17 protein levels significantly increased in urine, renal tissue, and glomeruli from diabetic rats, with a concomitant increase in glomerular albumin permeability. High glucose increased ADAM17 extracellular activity, NADPH oxidase activity, and albumin permeability in podocytes. These effects were reversed after treatment with ADAM17 inhibitor, in cells with downregulated ADAM17 expression, or after the addition of Klotho. Additionally, elevations of extracellular ADAM17 activity were observed in podocytes with the downregulation of Klotho expression. Our data indicate a novel mechanism whereby hyperglycemia deteriorates podocyte function via ADAM17 activation. We also demonstrated the ability of Klotho to protect podocyte function under hyperglycemic conditions in an ADAM17-dependent manner.

Sleep drive is coupled to tissue damage via shedding of Caenorhabditis elegans EGFR ligand SISS-1

The benefits of sleep extend beyond the nervous system. Peripheral tissues impact sleep regulation, and increased sleep is observed in response to damaging conditions, even those that selectively affect non-neuronal cells. However, the 'sleep need' signal released by stressed tissues is not known. Sleep in the nematode C. elegans is independent of circadian cues and can be triggered rapidly by damaging conditions. This stress-induced sleep is mediated by neurons that require the Epidermal Growth Factor Receptor (EGFR) for their sleep-promoting function, but the only known C. elegans EGFR ligand, LIN-3, is not required for sleep. Here we describe SISS-1 (stress-induced sleepless), an EGF family ligand that is required for stress-induced sleep. We show that SISS-1 overexpression induces sleep in an EGFR-dependent, sleep neuron-dependent manner. We find that SISS-1 undergoes stress-responsive shedding by the ADM-4/ADAM17 metalloprotease, and that the ADM-4 site of action depends on the tissue specificity of the stressor. Our findings support a model in which SISS-1 is released from damaged tissues to activate EGFR in sleep neurons, identifying a molecular link between cellular stress and organismal sleep drive. Our data also point to a mechanism insulating this sleep signal from EGFR-mediated signaling during development.

Muscle mass, muscle strength and the renin-angiotensin system

The renin-angiotensin system (RAS) is a classically known circulatory regulatory system. In addition to the previously known multi-organ circulatory form of the RAS, the existence of tissue RASs in individual organs has been well established. Skeletal muscle has also been identified as an organ with a distinct RAS. In recent years, the effects of RAS activation on skeletal muscle have been elucidated from several perspectives: differences in motor function due to genetic polymorphisms of RAS components, skeletal muscle dysfunction under conditions of excessive RAS activation such as heart failure, and the effects of the use of RAS inhibitors on muscle strength. In addition, the concept of the RAS itself has recently been expanded with the discovery of a 'protective arm' of the RAS formed by factors such as angiotensin-converting enzyme 2 and angiotensin 1-7. This has led to a new understanding of the physiological function of the RAS in skeletal muscle. This review summarizes the diverse physiological functions of the RAS in skeletal muscle and considers the potential of future therapeutic strategies targeting the RAS to overcome problems such as sarcopenia and muscle weakness associated with chronic disease.

ADAM Metallopeptidase domain 19 promotes skin fibrosis in systemic sclerosis via neuregulin-1

BACKGROUND

ADAM19 (ADAM Metallopeptidase Domain 19) is known to be involved in extracellular matrix (ECM) remodeling, yet its specific function in systemic sclerosis (SSc) fibrosis remains unclear.

OBJECTIVES

This study sought to clarify the role and underlying mechanism of ADAM19 in SSc skin fibrosis.

METHODS

The expression of ADAM19 was assessed in skin tissues of SSc and wound healing using publicly available transcriptome datasets. This analysis was further validated through real-time PCR, western blot, and immunostaining in our SSc cohort, as well as in a mouse model of hypochlorite (HOCl)-induced fibrosis. To downregulate the expression of ADAM19, ADAM19 siRNA was employed. The influence of ADAM19 on fibroblast transcriptomics was examined using bulk RNA-seq. Data analysis and visualization were conducted using R packages, including edgeR, limma, clusterProfiler, ggplot2, gseaplot2, and complexheatmap.

RESULTS

ADAM19 exhibited a significant upregulation in skin tissues of SSc patients, as well as in wound healing and a HOCl-induced fibrosis mouse model. Additionally, there was a notable positive correlation between ADAM19 and fibrosis-related genes, local skin score, Modified Rodnan skin score, skin thickness progression rate, and the presence of ARA antibodies in SSc patients. Furthermore, ADAM19 levels were markedly elevated in SSc primary dermal fibroblasts and TGF-β-stimulated healthy controls primary dermal fibroblasts. The downregulation of ADAM19 resulted in the repression of TGF-β-induced ECM deposition and fibroblast activation. ADAM19 was identified as a mediator for the shedding of neuregulin-1 (NRG1) in fibroblasts, a pro-fibrotic cytokine that must be cleaved to exert its function.

CONCLUSION

ADAM19 plays a role in TGF-β-induced ECM deposition and fibroblast activation by mediating the shedding of NRG1, ultimately contributing to the development of skin fibrosis in SSc.

Updates on Inflammatory Molecular Pathways Mediated by ADAM17 in Autoimmunity

ADAM17 is a member of the disintegrin and metalloproteinase (ADAM) family of transmembrane proteases with immunoregulatory activity in multiple signaling pathways. The functional ADAM17 is involved in the shedding of the ectodomain characterizing many substrates belonging to growth factors, cytokines, receptors, and adhesion molecules. The ADAM17-dependent pathways are known to be crucial in tumor development and progression and in the modulation of many pathological and physiological processes. In the last decade, ADAM17 was considered the driver of several autoimmune pathologies, and numerous substrate-mediated signal transduction pathways were identified. However, the discoveries made to date have led researchers to try to clarify the multiple mechanisms in which ADAM17 is involved and to identify any molecular gaps between the different transductional cascades. In this review, we summarize the most recent updates on the multiple regulatory activities of ADAM17, focusing on reported data in the field of autoimmunity.

Repurposing raltegravir for reducing inflammation and treating cancer: a bioinformatics analysis

Inflammation is a defensive mechanism that safeguards the human body against detrimental stimuli. Within this intricate process, ADAM17, a zinc-dependent metalloprotease, emerges as an indispensable element, fostering the activation of diverse inflammatory and growth factors within the organism. Nonetheless, ADAM17 malfunctions can augment the rate of growth, inflammatory factors, and subsequent damage. Thus, in this study, we examined and repurposed drugs to suppress the activity of ADAM17. To this end, we employed bioinformatics techniques such as molecular docking, molecular dynamics, and pharmacokinetic studies. Five FDA-approved drugs including Raltegravir, Conivaptan, Paclitaxel, Saquinavir, and Venetoclax with the ability to impede the activity of the ADAM17 metalloenzyme were identified. Moreover, these drugs did not include strong zinc-binding functional groups when verified by the ACE functional group finder. However, further in silico analysis has indicated that Raltegravir demonstrates a commendable interaction with the active site amino acids and exhibits the most favorable pharmacokinetic properties compared to others. Considering the results of bioinformatics tools, it can be concluded that Raltegravir as an antiviral drug could be repurposed to prevent severe inflammatory response and tumorigenesis resulting from ADAM17 malfunction.

Development of a Proteomic Workflow for the Identification of Heparan Sulphate Proteoglycan-Binding Substrates of ADAM17

Ectodomain shedding, which is the proteolytic release of transmembrane proteins from the cell surface, is crucial for cell-to-cell communication and other biological processes. The metalloproteinase ADAM17 mediates ectodomain shedding of over 50 transmembrane proteins ranging from cytokines and growth factors, such as TNF and EGFR ligands, to signalling receptors and adhesion molecules. Yet, the ADAM17 sheddome is only partly defined and biological functions of the protease have not been fully characterized. Some ADAM17 substrates (e.g., HB-EGF) are known to bind to heparan sulphate proteoglycans (HSPG), and we hypothesised that such substrates would be under-represented in traditional secretome analyses, due to their binding to cell surface or pericellular HSPGs. Thus, to identify novel HSPG-binding ADAM17 substrates, we developed a proteomic workflow that involves addition of heparin to solubilize HSPG-binding proteins from the cell layer, thereby allowing their mass spectrometry detection by heparin-treated secretome (HEP-SEC) analysis. Applying this methodology to murine embryonic fibroblasts stimulated with an ADAM17 activator enabled us to identify 47 transmembrane proteins that were shed in response to ADAM17 activation. This included known HSPG-binding ADAM17 substrates (i.e., HB-EGF, CX3CL1) and 14 novel HSPG-binding putative ADAM17 substrates. Two of these, MHC-I and IL1RL1, were validated as ADAM17 substrates by immunoblotting.

Euonymus hamiltonianus Extract Improves Amnesia in APPswe/Tau Transgenic and Scopolamine-Induced Dementia Models

Dementia is a syndrome exhibiting progressive impairments on cognition and behavior beyond the normal course of aging, and Alzheimer's disease (AD) is one of the neurodegenerative diseases known to cause dementia. We investigated the effect of KGC07EH, the 30% ethanol extract of Euonymus hamiltonianus, against amyloid-β (Aβ) production and cognitive dysfunction in dementia models. KGC07EH was treated on Hela cells expressing the Swedish mutant form of amyloid precursor protein (APP), and the AD triple transgenic (3× TG) mice were given KGC07EH orally during 11-14 months of age (100 and 300 mg/kg/day). SH-SY5Y cell line was used to test KGC07EH on scopolamine-induced elevation of acetylcholinesterase (AChE) activity. ICR mice were intraperitoneally injected with scopolamine, and KGC07EH was administered orally (50, 100, and 200 mg/kg/day) for 4 weeks. KGC07EH treatment decreased Aβ, sAPPβ-sw, and sAPPβ-wt levels and APP protein expressions while sAPPα was increased in Swedish mutant-transfected HeLa cells. KGC07EH treatment also significantly reduced the accumulation of Aβ plaques and tau tangles in the brain of 3× TG mice as well as improving the cognitive function. In SH-SY5Y cells cultured with scopolamine, KGC07EH dose-dependently attenuated the increase of AChE activity. KGC07EH also improved scopolamine-induced learning and memory impairment in scopolamine-injected mice, and in their cerebral cortex and hippocampus, the expression levels of p-ERK, p-CREB, p-Akt, and BDNF were attenuated. KGC07EH inhibits APP processing and Aβ production both in vitro and in vivo, while enhancing acetylcholine signaling and cognitive dysfunction which are the major symptoms of dementia.

Synthetic and non-synthetic inhibition of ADAM10 and ADAM17 reduces inflammation and oxidative stress in LPS-induced acute kidney injury in male and female mice

Acute kidney injury (AKI) is a severe medical condition that can lead to illness and death. A disintegrin and metalloprotease (ADAM) protein family is a potential treatment target for AKI due to its involvement in inflammation, growth, and differentiation. While ADAM10 and ADAM17 have been identified as significant contributors to inflammation, it is unclear whether they play a critical role in AKI. In this study, we induced AKI in male and female mice using lipopolysaccharide, a bacterial endotoxin that causes inflammation and oxidative stress. The role of kaempferol, which is found in many natural products and known to have antioxidant and anti-inflammatory activity in many pre-clinical studies, was investigated through ADAM10/17 enzymes in AKI. We also investigated the efficacy of a selective synthetic inhibitor named GW280264X for ADAM10/17 inhibition in AKI. Blood urea nitrogen and creatinine levels were measured in serum, while tumor necrosis factor-α, vascular adhesion molecule, interleukin (IL)-1β, glucose regulatory protein-78, IL-10, nuclear factor κ-B, thiobarbituric acid reactive substances, total thiol, ADAM10, and ADAM17 levels were measured in kidney tissue. We also evaluated kidney tissue histologically using hematoxylin and eosin, periodic acid-schiff, and caspase-3 staining. This research demonstrates that GW280264X and kaempferol reduces inflammation and oxidative stress, as evidenced by biochemical and histopathological results in AKI through ADAM10/17 inhibition. These findings suggest that inhibiting ADAM10/17 may be a promising therapeutic approach for treating acute kidney injury.

Inhibiting ADAM17 enhances the efficacy of olaparib in ovarian cancer spheroids

Acquired or de novo resistance to poly (ADP-ribose) polymerase inhibitors (PARPi) is a major challenge to ovarian cancer treatment. Therefore, strategies to overcome PARPi resistance are critical to improve prognosis. The purpose of this study is to evaluate whether inhibition of ADAM17 sensitizes ovarian cancer to treatment with olaparib, a PARPi, thereby bypassing resistance mechanisms and improving treatment response. Thus, we analyzed the effect of olaparib in combination with the ADAM17 inhibitor GW280264X in ovarian cancer using a 2D monolayer and a 3D spheroid model followed by a multicontent readout (viability, caspase activation and cytotoxicity). To emphasize the translational aspect of our work, we performed corresponding experiments on primary cells derived from ovarian cancer patients initially screened for their mutation status of the breast cancer gene (BRCA 1/2). In 2D, we observed a significant reduction in cell viability and a subsequent increase in apoptosis of the combined treatment (olaparib + GW280264X) compared with olaparib mono-treatment. The combined treatment allows a substantial dose reduction of olaparib rendering a strong synergistic effect. Using a 3D spheroid model from primary cells, we confirmed the 2D monoculture results and demonstrated not only increased caspase activity under the combined treatment but also a substantial gain in cytotoxicity compared to the mono-treatment. Our study proposes ADAM17 inhibition sensitizing ovarian cancer to olaparib treatment and improving treatment response.

Downregulation of PIK3IP1/TrIP on T cells is controlled by TCR signal strength, PKC, and metalloprotease-mediated cleavage

The protein known as PI3K-interacting protein (PIK3IP1), or transmembrane inhibitor of PI3K (TrIP), is highly expressed by T cells and can modulate PI3K activity in these cells. Several studies have also revealed that TrIP is rapidly downregulated following T cell activation. However, it is unclear how this downregulation is controlled. Using a novel monoclonal antibody that robustly stains cell-surface TrIP, we demonstrate that TrIP is lost from the surface of activated T cells in a manner dependent on the strength of signaling through the T cell receptor and specific downstream signaling pathways, in particular classical PKC isoforms. TrIP expression returns by 24 h after stimulation, suggesting that it may play a role in resetting T cell receptor signaling at later time points. We also provide evidence that ADAM family proteases are required for both constitutive and stimulation-induced downregulation of TrIP in T cells. Finally, by expressing truncated forms of TrIP in cells, we identify the region in the extracellular stalk domain of TrIP that is targeted for proteolytic cleavage.

Downregulation of PIK3IP1/TrIP on T cells is controlled by TCR signal strength, PKC and metalloprotease-mediated cleavage

The protein known as PI3K-interacting protein (PIK3IP1), or transmembrane inhibitor of PI3K (TrIP), is highly expressed by T cells and can modulate PI3K activity in these cells. Several studies have also revealed that TrIP is rapidly downregulated following T cell activation. However, it is unclear as to how this downregulation is controlled. Using a novel monoclonal antibody that robustly stains cell-surface TrIP, we demonstrate that TrIP is lost from the surface of activated T cells in a manner dependent on the strength of signaling through the T cell receptor (TCR) and specific downstream signaling pathways, in particular classical PKC isoforms. TrIP expression returns by 24 hours after stimulation, suggesting that it may play a role in resetting TCR signaling at later time points. We also provide evidence that ADAM family proteases are required for both constitutive and stimulation-induced downregulation of TrIP in T cells. Finally, by expressing truncated forms of TrIP in cells, we identify the region in the extracellular stalk domain of TrIP that is targeted for proteolytic cleavage.

Sesame oil downregulates the expression of ADAMTS-4 in high-fat diet-induced atherosclerosis

Atherosclerosis is a chronic inflammatory disease forming plaques in medium and large-sized arteries. ADAMTS-4 (a disintegrin and metalloproteinase with thrombospondin motifs-4) is an extracellular-matrix remodelling enzyme involved in the degradation of versican in the arterial wall. Recent reports indicated that increased expression of ADAMTS-4 is associated with plaque progression and vulnerability. Bioactive components of dietary oil, like sesame oil, are reported to have anti-inflammatory and antioxidant properties. Here, we studied the effect of sesame oil on regulating ADAMTS-4 in high-fat diet-induced atherosclerosis rat model. Our results indicated that sesame oil supplementation improved the anti-inflammatory and anti-oxidative status of the body. It also reduced atherosclerotic plaque formation in high-fat diet-fed rats. Our results showed that the sesame oil supplementation significantly down-regulated the expression of ADAMTS-4 in serum and aortic samples. The versican, the large proteoglycan substrate of ADAMTS-4 in the aorta, was downregulated to normal control level on sesame oil supplementation. This study, for the first time, reveals that sesame oil could down-regulate the expression of ADAMTS-4 in high-fat diet-induced atherosclerosis, imparting a new therapeutic potential for sesame oil in the management of atherosclerosis.

Inhibition of ADAM17 increases the cytotoxic effect of cisplatin in cervical spheroids and organoids

Introduction

Cervical cancer represents one of the main causes of female, cancer-related mortality worldwide. The majority of cancers are caused by human papillomaviruses such as HPV16 and HPV18. As chemotherapeutic resistance to first-line platinum treatment is still a predominant clinical challenge in advanced cervical cancer, novel treatment options including combinatorial therapies are urgently required to overcome chemotherapeutic resistance. Inhibition of A Disintegrin And Metalloproteinase (ADAM)-family members, heavily involved in tumour progression of a vast range of solid tumours, strongly improved response to chemotherapeutic treatment in other tumour entities including ovarian cancer.

Methods

We established two- and three-dimensional models derived from three traditional cervical cancer cell lines and ectocervical cancer-derived organoids. Following characterisation, these models were used to investigate their response to cisplatin treatment in the absence and presence of ADAM inhibitors using viability assays and automated live cell imaging.

Results

The pivotal role of the metalloprotease ADAM17 driving chemotherapy resistance was detectable in all ectocervical cultures irrespective of the model system used, whereas ADAM10 inhibition was predominantly effective only in loosely aggregated spheroids. We showed prominent differences regarding treatment responses between 2D monolayers compared to 3D spheroid and 3D organoid model systems. Particularly, the organoid system, regarded as the closest representation of primary tumours, exhibited reliably the combinatorial effect of ADAM17 inhibition and cisplatin in all three individual donors.

Discussion

As two- and three-dimensional models of the same cell lines differ in their responses to chemotherapy it is essential to validate treatment strategies in more advanced model systems representing the patient situation more realistically. Ectocervical organoids showed reliable results regarding treatment responses closely mimicking the primary tumours and could therefore serve as an important tool for personalized medicine in cervical cancer. These findings strengthen the role of ADAM17 as a potential novel target for combinatorial treatments to overcome chemoresistance in cervical cancer.

Immune signature and therapeutic approach of natural killer cell in chronic liver disease and hepatocellular carcinoma

Natural killer (NK) cells are one of the key members of innate immunity that predominantly reside in the liver, potentiating immune responses against viral infections or malignant tumors. It has been reported that changes in cell numbers and function of NK cells are associated with the development and progression of chronic liver diseases (CLDs) including non-alcoholic fatty liver disease, alcoholic liver disease, and chronic viral hepatitis. Also, it is known that the crosstalk between NK cells and hepatic stellate cells plays an important role in liver fibrosis and cirrhosis. In particular, the impaired functions of NK cells observed in CLDs consequently contribute to occurrence and progression of hepatocellular carcinoma (HCC). Chronic infections by hepatitis B or C viruses counteract the anti-tumor immunity of the host by producing the sheddases. Soluble major histocompatibility complex class I polypeptide-related sequence A (sMICA), released from the cell surfaces by sheddases, disrupts the interaction and affects the function of NK cells. Recently, the MICA/B-NK stimulatory receptor NK group 2 member D (NKG2D) axis has been extensively studied in HCC. HCC patients with low membrane-bound MICA or high sMICA concentration have been associated with poor prognosis. Therefore, reversing the sMICA-mediated downregulation of NKG2D has been proposed as an attractive strategy to enhance both innate and adaptive immune responses against HCC. This review aims to summarize recent studies on NK cell immune signatures and its roles in CLD and hepatocellular carcinogenesis and discusses the therapeutic approaches of MICA/B-NKG2D-based or NK cell-based immunotherapy for HCC.

Non-canonical function of ADAM10 in presynaptic plasticity

A Disintegrin And Metalloproteinase 10 (ADAM10) plays a pivotal role in shaping neuronal networks by orchestrating the activity of numerous membrane proteins through the shedding of their extracellular domains. Despite its significance in the brain, the specific cellular localization of ADAM10 remains not well understood due to a lack of appropriate tools. Here, using a specific ADAM10 antibody suitable for immunostainings, we observed that ADAM10 is localized to presynapses and especially enriched at presynaptic vesicles of mossy fiber (MF)-CA3 synapses in the hippocampus. These synapses undergo pronounced frequency facilitation of neurotransmitter release, a process that play critical roles in information transfer and neural computation. We demonstrate, that in conditional ADAM10 knockout mice the ability of MF synapses to undergo this type of synaptic plasticity is greatly reduced. The loss of facilitation depends on the cytosolic domain of ADAM10 and association with the calcium sensor synaptotagmin 7 rather than ADAM10's proteolytic activity. Our findings unveil a new role of ADAM10 in the regulation of synaptic vesicle exocytosis.

Photoreceptors inhibit pathological retinal angiogenesis through transcriptional regulation of Adam17 via c-Fos

Pathological retinal angiogenesis profoundly impacts visual function in vascular eye diseases, such as retinopathy of prematurity (ROP) in preterm infants and age-related macular degeneration in the elderly. While the involvement of photoreceptors in these diseases is recognized, the underlying mechanisms remain unclear. This study delved into the pivotal role of photoreceptors in regulating abnormal retinal blood vessel growth using an oxygen-induced retinopathy (OIR) mouse model through the c-Fos/A disintegrin and metalloprotease 17 (Adam17) axis. Our findings revealed a significant induction of c-Fos expression in rod photoreceptors, and c-Fos depletion in these cells inhibited pathological neovascularization and reduced blood vessel leakage in the OIR mouse model. Mechanistically, c-Fos directly regulated the transcription of Adam17 a shedding protease responsible for the production of bioactive molecules involved in inflammation, angiogenesis, and cell adhesion and migration. Furthermore, we demonstrated the therapeutic potential by using an adeno-associated virus carrying a rod photoreceptor-specific short hairpin RNA against c-fos which effectively mitigated abnormal retinal blood vessel overgrowth, restored retinal thickness, and improved electroretinographic (ERG) responses. In conclusion, this study highlights the significance of photoreceptor c-Fos in ROP pathology, offering a novel perspective for the treatment of this disease.

New insights into the function and pathophysiology of the ectodomain sheddase A Disintegrin And Metalloproteinase 10 (ADAM10)

The 'A Disintegrin And Metalloproteinase 10' (ADAM10) has gained considerable attention due to its discovery as an 'α-secretase' involved in the nonamyloidogenic processing of the amyloid precursor protein, thereby possibly preventing the excessive generation of the amyloid beta peptide, which is associated with the pathogenesis of Alzheimer's disease. ADAM10 was found to exert many additional functions, cleaving about 100 different membrane proteins. ADAM10 is involved in many pathophysiological conditions, ranging from cancer and autoimmune disorders to neurodegeneration and inflammation. ADAM10 cleaves its substrates close to the plasma membrane, a process referred to as ectodomain shedding. This is a central step in the modulation of the functions of cell adhesion proteins and cell surface receptors. ADAM10 activity is controlled by transcriptional and post-translational events. The interaction of ADAM10 with tetraspanins and the way they functionally and structurally depend on each other is another topic of interest. In this review, we will summarize findings on how ADAM10 is regulated and what is known about the biology of the protease. We will focus on novel aspects of the molecular biology and pathophysiology of ADAM10 that were previously poorly covered, such as the role of ADAM10 on extracellular vesicles, its contribution to virus entry, and its involvement in cardiac disease, cancer, inflammation, and immune regulation. ADAM10 has emerged as a regulator controlling cell surface proteins during development and in adult life. Its involvement in disease states suggests that ADAM10 may be exploited as a therapeutic target to treat conditions associated with a dysfunctional proteolytic activity.

Impacts of SARS-CoV-2 on brain renin angiotensin system related signaling and its subsequent complications on brain: A theoretical perspective

Cellular ACE2 (cACE2), a vital component of the renin-angiotensin system (RAS), possesses catalytic activity to maintain AngII and Ang 1-7 balance, which is necessary to prevent harmful effects of AngII/AT2R and promote protective pathways of Ang (1-7)/MasR and Ang (1-7)/AT2R. Hemostasis of the brain-RAS is essential for maintaining normal central nervous system (CNS) function. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a viral disease that causes multi-organ dysfunction. SARS-CoV-2 mainly uses cACE2 to enter the cells and cause its downregulation. This, in turn, prevents the conversion of Ang II to Ang (1-7) and disrupts the normal balance of brain-RAS. Brain-RAS disturbances give rise to one of the pathological pathways in which SARS-CoV-2 suppresses neuroprotective pathways and induces inflammatory cytokines and reactive oxygen species. Finally, these impairments lead to neuroinflammation, neuronal injury, and neurological complications. In conclusion, the influence of RAS on various processes within the brain has significant implications for the neurological manifestations associated with COVID-19. These effects include sensory disturbances, such as olfactory and gustatory dysfunctions, as well as cerebrovascular and brain stem-related disorders, all of which are intertwined with disruptions in the RAS homeostasis of the brain.

miRNAs mediate the impact of smoking on dental pulp stem cells via the p53 pathway

Cigarette smoke changes the genomic and epigenomic imprint of cells. In this study, we investigated the biological consequences of extended cigarette smoke exposure on dental pulp stem cells (DPSCs) and the potential roles of miRNAs. DPSCs were treated with various doses of cigarette smoke condensate (CSC) for up to 6 weeks. Cell proliferation, survival, migration, and differentiation were evaluated. Cytokine and miRNA expression were profiled. The results showed that extended exposure to CSC significantly impaired the regenerative capacity of the DPSCs. Bioinformatic analysis showed that the cell cycle pathway, cancer pathways (small cell lung cancer, pancreatic, colorectal, and prostate cancer), and pathways for TNF, TGF-β, p53, PI3K-Akt, mTOR, and ErbB signal transduction, were associated with altered miRNA profiles. In particular, 3 miRNAs has-miR-26a-5p, has-miR-26b-5p, and has-miR-29b-3p fine-tune the p53 and cell cycle signaling pathways to regulate DPSC cellular activities. The work indicated that miRNAs are promising targets to modulate stem cell regeneration and understanding miRNA-targeted genes and their associated pathways in smoking individuals have significant implications for disease control and prevention.

The interferon-rich skin environment regulates Langerhans cell ADAM17 to promote photosensitivity in lupus

The autoimmune disease lupus erythematosus (lupus) is characterized by photosensitivity, where even ambient ultraviolet radiation (UVR) exposure can lead to development of inflammatory skin lesions. We have previously shown that Langerhans cells (LCs) limit keratinocyte apoptosis and photosensitivity via a disintegrin and metalloprotease 17 (ADAM17)-mediated release of epidermal growth factor receptor (EGFR) ligands and that LC ADAM17 sheddase activity is reduced in lupus. Here, we sought to understand how the lupus skin environment contributes to LC ADAM17 dysfunction and, in the process, differentiate between effects on LC ADAM17 sheddase function, LC ADAM17 expression, and LC numbers. We show through transcriptomic analysis a shared IFN-rich environment in non-lesional skin across human lupus and three murine models: MRL/lpr, B6.Sle1yaa, and imiquimod (IMQ) mice. IFN-I inhibits LC ADAM17 sheddase activity in murine and human LCs, and IFNAR blockade in lupus model mice restores LC ADAM17 sheddase activity, all without consistent effects on LC ADAM17 protein expression or LC numbers. Anti-IFNAR-mediated LC ADAM17 sheddase function restoration is associated with reduced photosensitive responses that are dependent on EGFR signaling and LC ADAM17. Reactive oxygen species (ROS) is a known mediator of ADAM17 activity; we show that UVR-induced LC ROS production is reduced in lupus model mice, restored by anti-IFNAR, and is cytoplasmic in origin. Our findings suggest that IFN-I promotes photosensitivity at least in part by inhibiting UVR-induced LC ADAM17 sheddase function and raise the possibility that anifrolumab ameliorates lupus skin disease in part by restoring this function. This work provides insight into IFN-I-mediated disease mechanisms, LC regulation, and a potential mechanism of action for anifrolumab in lupus.

Cryo-EM reveals that iRhom2 restrains ADAM17 protease activity to control the release of growth factor and inflammatory signals

A disintegrin and metalloprotease 17 (ADAM17) is a membrane-tethered protease that triggers multiple signaling pathways. It releases active forms of the primary inflammatory cytokine tumor necrosis factor (TNF) and cancer-implicated epidermal growth factor (EGF) family growth factors. iRhom2, a rhomboid-like, membrane-embedded pseudoprotease, is an essential cofactor of ADAM17. Here, we present cryoelectron microscopy (cryo-EM) structures of the human ADAM17/iRhom2 complex in both inactive and active states. These reveal three regulatory mechanisms. First, exploiting the rhomboid-like hallmark of TMD recognition, iRhom2 interacts with the ADAM17 TMD to promote ADAM17 trafficking and enzyme maturation. Second, a unique iRhom2 extracellular domain unexpectedly retains the cleaved ADAM17 inhibitory prodomain, safeguarding against premature activation and dysregulated proteolysis. Finally, loss of the prodomain from the complex mobilizes the ADAM17 protease domain, contributing to its ability to engage substrates. Our results reveal how a rhomboid-like pseudoprotease has been repurposed during evolution to regulate a potent membrane-tethered enzyme, ADAM17, ensuring the fidelity of inflammatory and growth factor signaling.

Tigilanol Tiglate-Induced Changes in Secretome Profiles Alter C-Met Phosphorylation and Cell Surface Protein Expression in H357 Head and Neck Cancer Cells

Tigilanol tiglate (TT, also known as EBC-46) is a novel, plant-derived diterpene ester possessing anticancer and wound-healing properties. Here, we show that TT-evoked PKC-dependent S985 phosphorylation of the tyrosine kinase MET leads to subsequent degradation of tyrosine phosphorylated p-Y1003 and p-Y1234/5 MET species. PKC inhibition with BIM-1 blocked S985 phosphorylation of MET and led to MET cell surface accumulation. Treatment with metalloproteinase inhibitors prevented MET-ECD release into cell culture media, which was also blocked by PKC inhibitors. Furthermore, unbiased secretome analysis, performed using TMT-technology, identified additional targets of TT-dependent release of cell surface proteins from H357 head and neck cancer cells. We confirm that the MET co-signalling receptor syndecan-1 was cleaved from the cell surface in response to TT treatment. This was accompanied by rapid cleavage of the cellular junction adhesion protein Nectin-1 and the nerve growth factor receptor NGFRp75/TNFR16. These findings, that TT is a novel negative regulator of protumorigenic c-MET and NGFRp75/TNFR16 signalling, as well as regulating Nectin-1-mediated cell adhesion, further contribute to our understanding of the mode of action and efficacy of TT in the treatment of solid tumours.

The rs11684747 and rs55790676 SNPs of ADAM17 influence tuberculosis susceptibility and plasma levels of TNF, TNFR1, and TNFR2

Introduction

The proteolytic activity of A Disintegrin and Metalloproteinase 17 (ADAM17) regulates the release of tumor necrosis factor (TNF) and TNF receptors (TNFRs) from cell surfaces. These molecules play important roles in tuberculosis (TB) shaping innate immune reactions and granuloma formation.

Methods

Here, we investigated whether single nucleotide polymorphisms (SNPs) of ADAM17 influence TNF and TNFRs levels in 224 patients with active TB (ATB) and 118 healthy close contacts. Also, we looked for significant associations between SNPs of ADAM17 and ATB status. TNF, TNFR1, and TNFR2 levels were measured in plasma samples by ELISA. Four SNPs of ADAM17 (rs12692386, rs1524668, rs11684747, and rs55790676) were analyzed in DNA isolated from peripheral blood leucocytes. The association between ATB status, genotype, and cytokines was analyzed by multiple regression models.

Results

Our results showed a higher frequency of rs11684747 and rs55790676 in close contacts than ATB patients. Coincidentally, heterozygous to these SNPs of ADAM17 showed higher plasma levels of TNF compared to homozygous to their respective ancestral alleles. Strikingly, the levels of TNF and TNFRs distinguished participant groups, with ATB patients displaying lower TNF and higher TNFR1/TNFR2 levels compared to their close contacts.

Conclusion

These findings suggest a role for SNPs of ADAM17 in genetic susceptibility to ATB.

ADAM-17 Activity and Its Relation to ACE2: Implications for Severe COVID-19

There is a lack of studies aiming to assess cellular a disintegrin and metalloproteinase-17 (ADAM-17) activity in COVID-19 patients and the eventual associations with the shedding of membrane-bound angiotensin-converting enzyme 2 (mACE2). In addition, studies that investigate the relationship between ACE2 and ADAM-17 gene expressions in organs infected by SARS-CoV-2 are lacking. We used data from the Massachusetts general hospital COVID-19 study (306 COVID-19 patients and 78 symptomatic controls) to investigate the association between plasma levels of 33 different ADAM-17 substrates and COVID-19 severity and mortality. As a surrogate of cellular ADAM-17 activity, an ADAM-17 substrate score was calculated. The associations between soluble ACE2 (sACE2) and the ADAM-17 substrate score, renin, key inflammatory markers, and lung injury markers were investigated. Furthermore, we used data from the Genotype-Tissue Expression (GTEx) database to evaluate ADAM-17 and ACE2 gene expressions by age and sex in ages between 20-80 years. We found that increased ADAM-17 activity, as estimated by the ADAM-17 substrates score, was associated with COVID-19 severity (p = 0.001). ADAM-17 activity was also associated with increased mortality but did not reach statistical significance (p = 0.06). Soluble ACE2 showed the strongest positive correlation with the ADAM-17 substrate score, follow by renin, interleukin-6, and lung injury biomarkers. The ratio of ADAM-17 to ACE2 gene expression was highest in the lung. This study indicates that increased ADAM-17 activity is associated with severe COVID-19. Our findings also indicate that there may a bidirectional relationship between membrane-bound ACE2 shedding via increased ADAM-17 activity, dysregulated renin-angiotensin system (RAS) and immune signaling. Additionally, differences in ACE2 and ADAM-17 gene expressions between different tissues may be of importance in explaining why the lung is the organ most severely affected by COVID-19, but this requires further evaluation in prospective studies.

Mechanistic insight on the role of iRhom2-TNF-α-BAFF signaling pathway in various autoimmune disorders

iRhom2 is a crucial cofactor involved in upregulation of TNF receptors (TNFRs) and the pro-inflammatory cytokine tumor necrosis factor (TNF-) from the cell surface by ADAM17. Tumor necrosis factor- α converting enzyme (TACE) is another name given to ADAM17. Many membrane attached biologically active molecules are cleaved by this enzyme which includes TNFRs and the pro-inflammatory cytokine tumor necrosis factor- α. The TNF receptors are of two types TNFR1 and TNFR2. iRhom2 belongs to the pseudo-protease class of rhomboid family, its abundance is observed in the immune cells. Biological activity of ADAM17 is affected in multiple levels by the iRhom2. ADAM17 is trafficked into the Golgi apparatus by the action of iRhom2, where it gets matured proteolytically and is stimulated to perform its function on the cell surface. This process of activation of ADAM17 results in the protection of the organism from the cascade of inflammatory reactions, as this activation blocks the TNF- α mediated secretion responsible for inflammatory responses produced. Present paper illustrates about the iRhom2-TNF-α-BAFF signaling pathway and its correlation with several autoimmune disorders such as Rheumatoid Arthritis, Systemic Lupus Erythematosus, Hemophilia Arthropathy, Alzheimer's disease and Tylosis with esophageal cancer etc.

Role of the prefrontal cortical protease TACE/ADAM17 in neurobehavioral responses to chronic stress during adolescence

INTRODUCTION

Chronic adolescent stress profoundly affects prefrontal cortical networks regulating top-down behavior control. However, the neurobiological pathways contributing to stress-induced alterations in the brain and behavior remain largely unknown. Chronic stress influences brain growth factors and immune responses, which may, in turn, disrupt the maturation and function of prefrontal cortical networks. The tumor necrosis factor alpha-converting enzyme/a disintegrin and metalloproteinase 17 (TACE/ADAM17) is a sheddase with essential functions in brain maturation, behavior, and inflammatory responses. This study aimed to determine the impact of stress on the prefrontal cortex and whether TACE/ADAM17 plays a role in these responses.

METHODS

We used a Lewis rat model that incorporates critical elements of chronic psychosocial stress, such as uncontrollability, unpredictability, lack of social support, and re-experiencing of trauma.

RESULTS

Chronic stress during adolescence reduced the acoustic startle reflex and social interactions while increasing extracellular free water content and TACE/ADAM17 mRNA levels in the medial prefrontal cortex. Chronic stress altered various ethological behavioral domains in the observation home cages (decreased ingestive behaviors and increased walking, grooming, and rearing behaviors). A group of rats was injected intracerebrally either with a novel Accell™ SMARTpool TACE/ADAM17 siRNA or a corresponding siRNA vehicle (control). The RNAscope Multiplex Fluorescent v2 Assay was used to visualize mRNA expression. Automated puncta quantification and analyses demonstrated that TACE/ADAM17 siRNA administration reduced TACE/ADAM17 mRNA levels in the medial prefrontal cortex (59% reduction relative to control). We found that the rats that received prefrontal cortical TACE/ADAM17 siRNA administration exhibited altered eating patterns (e.g., increased food intake and time in the feeding zone during the light cycle).

CONCLUSION

This study supports that the prefrontal cortex is sensitive to adolescent chronic stress and suggests that TACE/ADAM17 may be involved in the brain responses to stress.

Immune System Dysregulation in the Progression of Multiple Sclerosis: Molecular Insights and Therapeutic Implications

Multiple sclerosis (MS), a prevalent neurological disorder, predominantly affects young adults and is characterized by chronic autoimmune activity. The study explores the immune system dysregulation in MS, highlighting the crucial roles of immune and non-neuronal cells in the disease's progression. This review examines the dual role of cytokines, with some like IL-6, TNF-α, and interferon-gamma (IFN-γ) promoting inflammation and CNS tissue injury, and others such as IL-4, IL-10, IL-37, and TGF-β fostering remyelination and protecting against MS. Elevated chemokine levels in the cerebrospinal fluid (CSF), including CCL2, CCL5, CXCL10, CXCL13, and fractalkine, are analyzed for their role in facilitating immune cell migration across the blood-brain barrier (BBB), worsening inflammation and neurodegeneration. The study also delves into the impact of auto-antibodies targeting myelin components like MOG and AQP4, which activate complement cascades leading to further myelin destruction. The article discusses how compromised BBB integrity allows immune cells and inflammatory mediators to infiltrate the CNS, intensifying MS symptoms. It also examines the involvement of astrocytes, microglia, and oligodendrocytes in the disease's progression. Additionally, the effectiveness of immunomodulatory drugs such as IFN-β and CD20-targeting monoclonal antibodies (e.g., rituximab) in modulating immune responses is reviewed, highlighting their potential to reduce relapse rates and delaying MS progression. These insights emphasize the importance of immune system dysfunction in MS development and progression, guiding the development of new therapeutic strategies. The study underscores recent advancements in understanding MS's molecular pathways, opening avenues for more targeted and effective treatments.

MicroRNAs and proteolytic cleavage of receptors in cancers: A comprehensive review of regulatory interactions and therapeutic implications

Cancer remains a challenging disease worldwide, necessitating innovative approaches to better comprehend its underlying molecular mechanisms and devise effective therapeutic strategies. Over the past decade, microRNAs (miRNAs) have emerged as crucial players in cancer progression due to their regulatory roles in various cellular processes. Moreover, the involvement of unwanted soluble receptors has gained increasing attention because they contribute to tumorigenesis or drug resistance by disrupting normal signaling pathways and neutralizing ligands. This comprehensive review explores the intricate interplay between miRNAs and unwanted-soluble receptors in the context of cancer biology. This study provides an analysis of the regulatory interactions between miRNAs and these receptors, elucidating how miRNAs can either suppress or enhance their expression. MiRNAs can directly target receptor transcripts, thereby regulating soluble receptor levels. They also modulate the proteolytic cleavage of membrane-bound receptors into soluble forms by targeting sheddases, such as ADAMs and MMPs. Furthermore, the review delves into the therapeutic potential of manipulating miRNAs to modulate unwanted soluble receptors. Various strategies, including synthetic miRNA mimics or anti-miRNAs, hold promise for restoring or inhibiting miRNA function to counteract aberrant receptor activity. Moreover, exploring miRNA-based delivery systems may provide targeted and precise therapies that minimizing off-target effects. In conclusion, this review sheds light on the intricate regulatory networks involving miRNAs and unwanted soluble receptors in cancer biology thereby uncovering novel therapeutic targets, and paving the way for developing innovative anti-cancer therapies.

iRhom2 regulates ectodomain shedding and surface expression of the major histocompatibility complex (MHC) class I

Proteolytic release of transmembrane proteins from the cell surface, the so called ectodomain shedding, is a key process in inflammation. Inactive rhomboid 2 (iRhom2) plays a crucial role in this context, in that it guides maturation and function of the sheddase ADAM17 (a disintegrin and metalloproteinase 17) in immune cells, and, ultimately, its ability to release inflammatory mediators such as tumor necrosis factor α (TNFα). Yet, the macrophage sheddome of iRhom2/ADAM17, which is the collection of substrates that are released by the proteolytic complex, is only partly known. In this study, we applied high-resolution proteomics to murine and human iRhom2-deficient macrophages for a systematic identification of substrates, and therefore functions, of the iRhom2/ADAM17 proteolytic complex. We found that iRhom2 loss suppressed the release of a group of transmembrane proteins, including known (e.g. CSF1R) and putative novel ADAM17 substrates. In the latter group, shedding of major histocompatibility complex class I molecules (MHC-I) was consistently reduced in both murine and human macrophages when iRhom2 was ablated. Intriguingly, it emerged that in addition to its shedding, iRhom2 could also control surface expression of MHC-I by an undefined mechanism. We have demonstrated the biological significance of this process by using an in vitro model of CD8+ T-cell (CTL) activation. In this model, iRhom2 loss and consequent reduction of MHC-I expression on the cell surface of an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line dampened activation of autologous CTLs and their cell-mediated cytotoxicity. Taken together, this study uncovers a new role for iRhom2 in controlling cell surface levels of MHC-I by a dual mechanism that involves regulation of their surface expression and ectodomain shedding.

Endothelial Protein C Receptor and Its Impact on Rheumatic Disease

Endothelial Protein C Receptor (EPCR) is a key regulator of the activated protein C anti-coagulation pathway due to its role in the binding and activation of this protein. EPCR also binds to other ligands such as Factor VII and X, γδ T-cells, plasmodium falciparum erythrocyte membrane protein 1, and Secretory group V Phospholipases A2, facilitating ligand-specific functions. The functions of EPCR can also be regulated by soluble (s)EPCR that competes for the binding sites of membrane-bound (m)EPCR. sEPCR is created when mEPCR is shed from the cell surface. The propensity of shedding alters depending on the genetic haplotype of the EPCR gene that an individual may possess. EPCR plays an active role in normal homeostasis, anti-coagulation pathways, inflammation, and cell stemness. Due to these properties, EPCR is considered a potential effector/mediator of inflammatory diseases. Rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus are autoimmune/inflammatory conditions that are associated with elevated EPCR levels and disease activity, potentially driven by EPCR. This review highlights the functions of EPCR and its contribution to rheumatic diseases.

Photoaffinity labeling coupled with proteomics identify PDI-ADAM17 module is targeted by (-)-vinigrol to induce TNFR1 shedding and ameliorate rheumatoid arthritis in mice

Various biological agents have been developed to target tumor necrosis factor alpha (TNF-α) and its receptor TNFR1 for the rheumatoid arthritis (RA) treatment, whereas small molecules modulating such cytokine receptors are rarely reported in comparison to the biologicals. Here, by revealing the mechanism of action of vinigrol, a diterpenoid natural product, we show that inhibition of the protein disulfide isomerase (PDI, PDIA1) by small molecules activates A disintegrin and metalloprotease 17 (ADAM17) and then leads to the TNFR1 shedding on mouse and human cell membranes. This small-molecule-induced receptor shedding not only effectively blocks the inflammatory response caused by TNF-α in cells, but also reduces the arthritic score and joint damage in the collagen-induced arthritis mouse model. Our study indicates that targeting the PDI-ADAM17 signaling module to regulate the shedding of cytokine receptors by the chemical approach constitutes a promising strategy for alleviating RA.

The Important Role of Phosphatidylserine, ADAM17, TNF-Alpha, and Soluble MER on Efferocytosis Activity in Central Obesity

Background

Obesity is expected to hinder efferocytosis due to ADAM17-mediated cleavage of the MER tyrosine kinase receptor, producing soluble MER (sMER) that disrupts MERTK binding to cell death markers. However, the intracellular efferocytosis pathway in central obesity remains elusive, particularly the role of low-grade chronic inflammation in its initiation and identification of binding signals that disrupt efferocytosis.

Objective

We investigate the efferocytosis signaling pathway in men with central obesity and its relationship with inflammation, cell death, and related processes.

Methods

A cross-sectional study was conducted, and clinical data and blood samples were collected from 56 men with central obesity (obese group) and 29 nonobese individuals (control group). Clinical evaluations and predefined biochemical screening tests were performed. The efferocytosis signaling pathway was investigated by measuring phosphatidylserine (PS), ADAM17, TNF-alpha (TNF-α), and sMER.

Results

Metabolic syndrome was detected in more than half of the participants in the obese group according to the predefined tests. Mean levels of PS, TNF-α, and sMER were higher in the obese group but not significantly different from those of the control group. Further analysis based on waist circumference (WC) ranges in the obese group revealed a significant increase in PS and sMER levels between the control group and the obese group with WC greater than 120 cm. ADAM17 levels were significantly higher in the obese group than in the control group. PS was positively correlated with WC and ADAM17. ADAM17 was positively correlated with TNF-α and sMER, indicating impaired efferocytosis.

Conclusions

Central obesity appeared to cause a disturbance in efferocytosis that began with cell damage and death, along with an enlargement of the WC and an ongoing inflammatory response. Efferocytosis was disrupted by proinflammatory cytokine regulators, which induced the production of sMER and interfered with the efferocytosis process.

Single cell analysis of short-term dry eye induced changes in cornea immune cell populations

Background

Dry eye causes corneal inflammation, epitheliopathy and sensorineural changes. This study evaluates the hypothesis that dry eye alters the percentages and transcriptional profiles of immune cell populations in the cornea.

Methods

Desiccating stress (DS) induced dry eye was created by pharmacologic suppression of tear secretion and exposure to drafty low humidity environment. Expression profiling of corneal immune cells was performed by single-cell RNA sequencing (scRNA-seq). Cell differentiation trajectories and cell fate were modeled through RNA velocity analysis. Confocal microscopy was used to immunodetect corneal immune cells. Irritation response to topical neurostimulants was assessed.

Results

Twelve corneal immune cell populations based on their transcriptional profiles were identified at baseline and consist of monocytes, resident (rMP) and MMP12/13 high macrophages, dendritic cells (cDC2), neutrophils, mast cells, pre T/B cells, and innate (γDT, ILC2, NK) and conventional T and B lymphocytes. T cells and resident macrophages (rMP) were the largest populations in the normal cornea comprising 18.6 and 18.2 percent, respectively. rMP increased to 55.2% of cells after 5 days of DS. Significant changes in expression of 1,365 genes (adj p < 0.0001) were noted in rMP with increases in cytokines and chemokines (Tnf, Cxcl1, Ccl12, Il1rn), inflammatory markers (Vcam, Adam17, Junb), the TAM receptor (Mertk), and decreases in complement and MHCII genes. A differentiation trajectory from monocytes to terminal state rMP was found. Phagocytosis, C-type lectin receptor signaling, NF-kappa B signaling and Toll-like receptor signaling were among the pathways with enhanced activity in these cells. The percentage of MRC1+ rMPs increased in the cornea and they were observed in the basal epithelium adjacent to epithelial nerve plexus. Concentration of the chemokine CXCL1 increased in the cornea and it heightened irritation/pain responses to topically applied hypertonic saline.

Conclusion

These findings indicate that DS recruits monocytes that differentiate to macrophages with increased expression of inflammation associated genes. The proximity of these macrophages to cornea nerves and their expression of neurosensitizers suggests they contribute to the corneal sensorineural changes in dry eye.

Expression of ADAM17 and its clinical value for patients with pernicious placenta previa: A retrospective study of 148 PPP patients underwent cesarean section

To explore the expression and the diagnostic value of ADAM17 in pernicious placenta previa (PPP) combined placental accreta. A total of 148 PPP patients were enrolled and divided into 2 groups: 62 patients with placenta accrete (PPP with PA group) and 86 patients without placenta accrete (PPP without PA group). In the same period, 74 pregnant women without PPP who had undergone cesarean section were selected as controls. The levels of ADAM17 were detected by qt-PCR. Diagnostic efficiency of ADAM17 were evaluated by receiver operating characteristics curve. ADAM17 was higher expression in PPP patients. Multivariate analysis showed that ADAM17 was related to gravida times (HR = 2.43 95% CI, 1.25-3.31), history of cesarean delivery (HR = 3.44, 95% CI = 2.24-4.28), history of abortions (HR = 2.22, 95% CI = 1.57-3.06) for PPP with PA patients and gravida times (HR = 2.01, 95% CI = 1.45-2.86), history of cesarean delivery (HR = 1.89, 95% CI = 1.33-2.48) for PPP patients without PA. Diagnostic efficiency of ADAM17 indicated that the sensitivity and specificity of ADAM17 detection for PPP with PA were 74.41% and 67.21% and for PPP without PA were 89.29% and 85.52%. Area under curve were 0.7876 (0.7090-0.8661) for PPP with PA and 0.9443 (0.9136-0.9750) for PPP without PA. Insummary, ADAM17 was higher expression in patients with PPP. ADAM17 was associated with gravida times, history of cesarean delivery, history of abortions. It also indicated a better diagnostic efficiency for patients with PPP. Further larger sample, multicenter studies should be conducted to confirm the conclusion from our study.

Exploring crucial structural attributes of quinolinyl methoxyphenyl sulphonyl-based hydroxamate derivatives as ADAM17 inhibitors through classification-dependent molecular modelling approaches

A Disintegrin and Metalloproteinase 17 (ADAM17), a Zn2+-dependent metalloenzyme of the adamalysin family of the metzincin superfamily, is associated with various pathophysiological conditions including rheumatoid arthritis and cancer. However, no specific inhibitors have been marketed yet for ADAM17-related disorders. In this study, 94 quinolinyl methoxyphenyl sulphonyl-based hydroxamates as ADAM17 inhibitors were subjected to classification-based molecular modelling and binding pattern analysis to identify the significant structural attributes contributing to ADAM17 inhibition. The statistically validated classification-based models identified the importance of the P1' substituents such as the quinolinyl methoxyphenyl sulphonyl group of these compounds for occupying the S1' - S3' pocket of the enzyme. The quinolinyl function of these compounds was found to explore stable binding of the P1' substituents at the S1' - S3' pocket whereas the importance of the sulphonyl and the orientation of the P1' moiety also revealed stable binding. Based on the outcomes of the current study, four novel compounds of different classes were designed as promising ADAM17 inhibitors. These findings regarding the crucial structural aspects and binding patterns of ADAM17 inhibitors will aid the design and discovery of novel and effective ADAM17 inhibitors for therapeutic advancements of related diseases.

Cleavage of the pseudoprotease iRhom2 by the signal peptidase complex reveals an ER-to-nucleus signaling pathway

iRhoms are pseudoprotease members of the rhomboid-like superfamily and are cardinal regulators of inflammatory and growth factor signaling; they function primarily by recognizing transmembrane domains of their clients. Here, we report a mechanistically distinct nuclear function of iRhoms, showing that both human and mouse iRhom2 are non-canonical substrates of signal peptidase complex (SPC), the protease that removes signal peptides from secreted proteins. Cleavage of iRhom2 generates an N-terminal fragment that enters the nucleus and modifies the transcriptome, in part by binding C-terminal binding proteins (CtBPs). The biological significance of nuclear iRhom2 is indicated by elevated levels in skin biopsies of patients with psoriasis, tylosis with oesophageal cancer (TOC), and non-epidermolytic palmoplantar keratoderma (NEPPK); increased iRhom2 cleavage in a keratinocyte model of psoriasis; and nuclear iRhom2 promoting proliferation of keratinocytes. Overall, this work identifies an unexpected SPC-dependent ER-to-nucleus signaling pathway and demonstrates that iRhoms can mediate nuclear signaling.

The protease ADAM17 at the crossroads of disease: revisiting its significance in inflammation, cancer, and beyond

The protease A Disintegrin And Metalloproteinase 17 (ADAM17) plays a central role in the pathophysiology of several diseases. ADAM17 is involved in the cleavage and shedding of at least 80 known membrane-tethered proteins, which subsequently modulate several intracellular signaling pathways, and therefore alter cell behavior. Dysregulated expression and/or activation of ADAM17 has been linked to a wide range of autoimmune and inflammatory diseases, cancer, and cardiovascular disease. In this review, we provide an overview of the current state of knowledge from preclinical models and clinical data on the diverse pathophysiological roles of ADAM17, and discuss the mechanisms underlying ADAM17-mediated protein shedding and the potential therapeutic implications of targeting ADAM17 in these diseases.

Role of Metalloproteinases in Diabetes-associated Mild Cognitive Impairment

Diabetes has been linked to an increased risk of mild cognitive impairment (MCI), a condition characterized by a subtle cognitive decline that may precede the development of dementia. The underlying mechanisms connecting diabetes and MCI involve complex interactions between metabolic dysregulation, inflammation, and neurodegeneration. A critical mechanism implicated in diabetes and MCI is the activation of inflammatory pathways. Chronic low-grade inflammation, as observed in diabetes, can lead to the production of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and interferon-gamma (IFNγ), each of which can exacerbate neuroinflammation and contribute to cognitive decline. A crucial enzyme involved in regulating inflammation is ADAM17, a disintegrin, and metalloproteinase, which can cleave and release TNF-α from its membrane-bound precursor and cause it to become activated. These processes, in turn, activate additional inflammation-related pathways, such as AKT, NF-κB, NLP3, MAPK, and JAK-STAT pathways. Recent research has provided novel insights into the role of ADAM17 in diabetes and neurodegenerative diseases. ADAM17 is upregulated in both diabetes and Alzheimer's disease, suggesting a shared mechanism and implicating inflammation as a possible contributor to much broader forms of pathology and pointing to a possible link between inflammation and the emergence of MCI. This review provides an overview of the different roles of ADAM17 in diabetes-associated mild cognitive impairment diseases. It identifies mechanistic connections through which ADAM17 and associated pathways may influence the emergence of mild cognitive impairment.

Proximity extracellular protein-protein interaction analysis of EGFR using AirID-conjugated fragment of antigen binding

Receptor proteins, such as epidermal growth factor receptor (EGFR), interact with other proteins in the extracellular region of the cell membrane to drive intracellular signalling. Therefore, analysis of extracellular protein-protein interactions (exPPIs) is important for understanding the biological function of receptor proteins. Here, we present an approach using a proximity biotinylation enzyme (AirID) fusion fragment of antigen binding (FabID) to analyse the proximity exPPIs of EGFR. AirID was C-terminally fused to the Fab fragment against EGFR (EGFR-FabID), which could then biotinylate the extracellular region of EGFR in several cell lines. Liquid Chromatography-Mass Spectrometry (LC-MS/MS) analysis indicated that many known EGFR interactors were identified as proximity exPPIs, along with many unknown candidate interactors, using EGFR-FabID. Interestingly, these proximity exPPIs were influenced by treatment with EGF ligand and its specific kinase inhibitor, gefitinib. These results indicate that FabID provides accurate proximity exPPI analysis of target receptor proteins on cell membranes with ligand and drug responses.

Role of ADAM and ADAMTS proteases in pathological tissue remodeling

Pathological tissue remodeling is closely associated with the occurrence and aggravation of various diseases. A Disintegrin And Metalloproteinases (ADAM), as well as A Disintegrin And Metalloproteinase with ThromboSpondin motifs (ADAMTS), belong to zinc-dependent metalloproteinase superfamily, are involved in a range of pathological states, including cancer metastasis, inflammatory disorders, respiratory diseases and cardiovascular diseases. Mounting studies suggest that ADAM and ADAMTS proteases contribute to the development of tissue remodeling in various diseases, mainly through the regulation of cell proliferation, apoptosis, migration and extracellular matrix remodeling. This review focuses on the roles of ADAM and ADAMTS proteinases in diseases with pathological tissue remodeling, with particular emphasis on the molecular mechanisms through which ADAM and ADAMTS proteins mediate tissue remodeling. Some of these reported proteinases have defined protective or contributing roles in indicated diseases, while their underlying regulation is obscure. Future studies are warranted to better understand the catalytic and non-catalytic functions of ADAM and ADAMTS proteins, as well as to evaluate the efficacy of targeting these proteases in pathological tissue remodeling.

Predictive Roles of ADAM17 in Patient Survival and Immune Cell Infiltration in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the deadliest malignant tumour worldwide. The metalloproteinase ADAM17 is associated with tumour formation and development; however, its significance in HCC is unclear. This study aimed to investigate the role of ADAM17 in HCC and the correlation between its expression and immune cell infiltration. ADAM17 expression was analysed in pan-cancer and HCC tissues using The Cancer Genome Atlas and Genotype-Tissue Expression datasets. Kaplan-Meier survival analysis displayed a negative association between ADAM17 expression and the overall survival of patients with HCC. High ADAM17 expression was linked to poor tumour/node (T/N) stage and alpha fetoprotein (AFP) levels. Gene Set Enrichment Analysis, Gene Ontology, and Kyoto Encyclopaedia of Genes and Genomes analyses revealed the enrichment of several pathways, including epithelial-mesenchymal transition, inflammatory response, Hedgehog, and KRAS signalling, in patients with upregulated ADAM17. ADAM17 was shown to be positively correlated with immune cell infiltration and immune checkpoint expression via the Tumour Immune Estimation Resource (TIMER) database and immunohistochemistry analyses. Protein-protein interaction (PPI) network analysis revealed that ADAM17 plays a core role in cancer development and immune evasion. In vitro and in vivo experiments demonstrated that ADAM17 influences HCC growth and metastasis. In conclusion, ADAM17 is upregulated in most cancers, particularly HCC, and is critical in the development and immune evasion of HCC.

Probenecid ameliorates testosterone-induced benign prostatic hyperplasia: Implications of PGE-2 on ADAM-17/EGFR/ERK1/2 signaling cascade

Benign prostatic hyperplasia (BPH) is one of the most prevalent clinical disorders in the elderly. Probenecid (Prob) is a well-known FDA-approved therapy for gout owing to its uricosuric effect. The present study evaluated the use of Prob for BPH as a COX-2 inhibitor. Prob (100 and 200 mg/kg) was intraperitoneally injected into male Wistar rats daily for 3 weeks. In the second week, testosterone (3 mg/kg) was subcutaneously injected to induce BPH. Compared with BPH-induced rats, Prob treatment reduced prostate weight and index and improved histopathological architecture. The protease activity of ADAM-17/TACE and its ligands (TGF-α and TNF-α) were regulated by prob, which in turn abolished EGFR phosphorylation, and several inflammatory mediators (COX-2, PGE2, NF-κB (p65), and IL-6) were suppressed. By reducing the nuclear import of extracellular regulated kinase protein 1/2 (ERK1/2), Prob helped re-establish the usual equilibrium between antiapoptotic proteins like Bcl-2 and cyclin D1 and proapoptotic proteins like Bax. All of these data point to Prob as a promising treatment for BPH because of its ability to inhibit COX-2-syntheiszed PGE2 and control the ADAM-17/TGF-α-induced EGFR/ERK1/2 signaling cascade. These findings might help to repurpose Prob for the treatment of BPH.