Amphiregulin Research Articles

Abstract 505: Cross Talk Between T Cells And Vascular Smooth Muscle Cells May Contribute To Phenotypic Changes In Human Coronary Plaque

Background: The atherosclerotic plaque is a complex niche composed of immune cells including T cells and macrophages as well as vascular smooth muscle cells. How T cells interact with the plaque microenvironment is not well understood. Objective: To map the crosstalk between T cells, macrophages, and smooth muscle cells. Methods/Results: We performed single cell RNAseq using the 10x transcriptomics platform in coronary plaque samples from 12 patients, who underwent heart transplantation. We found a high proportion of macrophages as well as T cells, many of which display a memory phenotype that was confirmed by immunohistochemistry. Ligand-receptor computational analysis demonstrated significant cross talk between T cells, macrophages, and smooth muscle cells. One cytokine of interest is amphiregulin (AREG), which has been shown to mediate tissue healing and fibrosis. Of note, AREG expression appears to increase as coronary plaques progress from early lipid-rich stages to more advanced stages. To elucidate the effects of AREG on smooth muscle cells, we treated human coronary artery smooth muscle cells (hCASMCs) in vitro with recombinant AREG and found increased cell proliferation compared to control (P<0.001). Bulk RNAseq profiling of hCASMCs showed activation of pathways that promote inflammation, proliferation, and fibrosis (Figure 1). Conclusion: Taken together, our findings suggest that cross talk between T cells and smooth muscle cells, partially through AREG production by T cells, may contribute to plaque progression.

The Amphiregulin/EGFR axis protects from lupus nephritis via downregulation of pathogenic CD4+ T helper cell responses

Systemic lupus erythematosus (SLE) is a common autoimmune disorder with a complex and poorly understood immuno-pathogenesis. Lupus nephritis (LN) is a frequent and difficult to treat complication, which causes high morbidity and mortality. The multifunctional cytokine amphiregulin (AREG) has been implicated in SLE pathogenesis, but its function in LN currently remains unknown. We thus studied the model of pristane-induced LN and found increasing renal and systemic AREG expression during the course of disease. Importantly, renal injury was significantly aggravated in the absence of AREG, revealing a net anti-inflammatory role. Analyses of immune responses showed dual effects. On the one hand, AREG enhanced activation of pro-inflammatory myeloid cells, which however did not play a major role for the course of LN. More importantly, on the other hand, AREG strongly suppressed pathogenic cytokine production by T helper effector cells. This effect was more general in nature and could be reproduced in response to antigen immunization. Since AREG has been postulated to downregulate T cell responses via enhancing Treg suppressive capacity, we followed up on this aspect. Interestingly, however, in vitro studies revealed potential direct and Treg independent effects of AREG on T helper effector cells. In favor of this notion, we found significantly enhanced T cell responses and consecutive aggravation of LN, only if epidermal growth factor receptor (EGFR) signaling was abrogated in total T cells, but not if the EGFR was absent on Tregs alone. Finally, we also found enhanced AREG expression in plasma and renal biopsies of patients with LN, supporting the relevance of our findings for human disease. In summary, our data identify AREG as an anti-inflammatory mediator of LN via broad downregulation of pathogenic T cell immunity. These findings further highlight the AREG/EGFR axis as a potential therapeutic target.

AREG is involved in scleral remodeling in form-deprivation myopia via the ERK1/2-MMP-2 pathway.

Previous studies have found that amphiregulin (AREG) may participate in eye elongation during the development of myopia, but the mechanism remains unclear. Here, we tested tear concentrations of AREG in adults and detected the role of AREG in scleral remodeling in form-deprivation myopia (FDM) in guinea pigs. We found the tear concentrations of AREG in myopes were significantly higher than those in emmetropes using enzyme-linked immunosorbent assay (ELISA). Tear concentrations of AREG were negatively correlated with spherical equivalent refraction and positively correlated with axial length (AL) and AL/corneal radii. We then used RNAi, DNA transfection and PD98059 treatments to determine the effects of AREG on extracellular signal-regulated kinase 1/2 (ERK1/2) and matrix metalloprotease-2 (MMP-2) in primary scleral fibroblasts (SFs). The hypothesis was further verified via loss- and gain-of-function experiments by intravitreal application of anti-AREGantibody (anti-AR) orAREG in form-deprivation eyes in guinea pigs. Immunofluorescence assay was used for cell type identification. Western-blot and q-PCR were used for the detection of relative expressions. Transmission electron microscopy was performed for posterior scleral observation. In vitro, we found AREG overexpression increased phospho-ERK1/2 and MMP-2 expression, while depletion of AREG inhibited their expressions. PD98059 (an effective ERK1/2 inhibitor) inhibited AREG-induced MMP-2 upregulation. In vivo, we found anti-AR treatments suppressed FDM by inhibiting scleral remodeling, while AREG treatments promoted FDM. Our results suggest that AREG in tear fluids can serve as a potential biomarker in myopes. AREG is involved in scleral remodeling through the ERK1/2-MMP-2 pathway. AREG is a potential target for myopia control.

Human Coronary Plaque T Cells Are Clonal and Cross-React to Virus and Self.

Coronary artery disease is an incurable, life-threatening disease that was once considered primarily a disorder of lipid deposition. Coronary artery disease is now also characterized by chronic inflammation' notable for the buildup of atherosclerotic plaques containing immune cells in various states of activation and differentiation. Understanding how these immune cells contribute to disease progression may lead to the development of novel therapeutic strategies. We used single-cell technology and in vitro assays to interrogate the immune microenvironment of human coronary atherosclerotic plaque at different stages of maturity. In addition to macrophages, we found a high proportion of αβ T cells in the coronary plaques. Most of these T cells lack high expression of CCR7 and L-selectin, indicating that they are primarily antigen-experienced memory cells. Notably, nearly one-third of these cells express the HLA-DRA surface marker, signifying activation through their TCRs (T-cell receptors). Consistent with this, TCR repertoire analysis confirmed the presence of activated αβ T cells (CD4<CD8), exhibiting clonal expansion of specific TCRs. Interestingly, we found that these plaque T cells had TCRs specific for influenza, coronavirus, and other viral epitopes, which share sequence homologies to proteins found on smooth muscle cells and endothelial cells, suggesting potential autoimmune-mediated T-cell activation in the absence of active infection. To better understand the potential function of these activated plaque T cells, we then interrogated their transcriptome at the single-cell level. Of the 3 T-cell phenotypic clusters with the highest expression of the activation marker HLA-DRA, 2 clusters expressed a proinflammatory and cytolytic signature characteristic of CD8 cells, while the other expressed AREG (amphiregulin), which promotes smooth muscle cell proliferation and fibrosis, and, thus, contributes to plaque progression. Taken together, these findings demonstrate that plaque T cells are clonally expanded potentially by antigen engagement, are potentially reactive to self-epitopes, and may interact with smooth muscle cells and macrophages in the plaque microenvironment.

Targeting the EGFR-ERK axis using the compatible solute ectoine to stabilize CFTR mutant F508del.

Mutations in the CFTR gene lead to cystic fibrosis, a genetic disease associated with chronic infection and inflammation and ultimately respiratory failure. The most common CF-causing mutation is F508del and CFTR modulators (correctors and potentiators) are being developed to rescue its trafficking and activity defects. However, there are currently no modulators that stabilize the rescued membrane F508del-CFTR which is endocytosed and quickly degraded resulting in a shorter half-life than wild-type (WT). We previously reported that the extracellular signal-regulated kinase (ERK) MAPK pathway is involved in CFTR degradation upon cigarette smoke exposure. Interestingly, we found that ERK phosphorylation was increased in CF human bronchial epithelial (HBE) cells (CF-HBE41o- and primary CF-HBE) compared to non-CF controls, and this was likely due to signaling by the epidermal growth factor receptor (EGFR). EGFR can be activated by several ligands, and we provide evidence that amphiregulin (AREG) is important for activating this signaling axis in CF. The natural osmolyte ectoine stabilizes membrane macromolecules. We show that ectoine decreases ERK phosphorylation, increases the half-life of rescued CFTR, and increases CFTR-mediated chloride transport in combination with the CFTR corrector VX-661. Additionally, ectoine reduces production of AREG and interleukin-8 by CF primary bronchial epithelial cells. In conclusion, EGFR-ERK signaling negatively regulates CFTR and is hyperactive in CF, and targeting this axis with ectoine may prove beneficial for CF patients.

Static Stretch Increases the Pro-Inflammatory Response of Rat Type 2 Alveolar Epithelial Cells to Dynamic Stretch.

Background: Mechanical ventilation (MV) inflicts stress on the lungs, initiating or increasing lung inflammation, so-called ventilator-induced lung injury (VILI). Besides overdistention, cyclic opening-and-closing of alveoli (atelectrauma) is recognized as a potential mechanism of VILI. The dynamic stretch may be reduced by positive end-expiratory pressure (PEEP), which in turn increases the static stretch. We investigated whether static stretch modulates the inflammatory response of rat type 2 alveolar epithelial cells (AECs) at different levels of dynamic stretch and hypothesized that static stretch increases pro-inflammatory response of AECs at given dynamic stretch. Methods: AECs, stimulated and not stimulated with lipopolysaccharide (LPS), were subjected to combinations of static (10, 20, and 30%) and dynamic stretch (15, 20, and 30%), for 1 and 4 h. Non-stretched AECs served as control. The gene expression and secreted protein levels of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) were studied by real-time polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. The effects of static and dynamic stretch were assessed by two-factorial ANOVA with planned effects post-hoc comparison according to Šidák. Statistical significance was considered for p < 0.05. Results: In LPS-stimulated, but not in non-stimulated rat type 2 AECs, compared to non-stretched cells: 1) dynamic stretch increased the expression of amphiregulin (AREG) (p < 0.05), MCP-1 (p < 0.001), and MIP-2 (<0.05), respectively, as well as the protein secretion of IL-6 (p < 0.001) and MCP-1 (p < 0.05); 2) static stretch increased the gene expression of MCP-1 (p < 0.001) and MIP-2, but not AREG, and resulted in higher secretion of IL-6 (p < 0.001), but not MCP-1, while MIP-2 was not detectable in the medium. Conclusion: In rat type 2 AECs stimulated with LPS, static stretch increased the pro-inflammatory response to dynamic stretch, suggesting a potential pro-inflammatory effect of PEEP during mechanical ventilation at the cellular level.

Regorafenib inhibits epithelial-mesenchymal transition and suppresses cholangiocarcinoma metastasis via YAP1-AREG axis

Cholangiocarcinoma (CCA) is a subtype of bile duct cancer usually diagnosed late with a low survival rate and no satisfactorily systemic treatment. Recently, regorafenib has been accepted as a second-line treatment for CCA patients. In this study, we investigated the potential signal transduction pathways mediated by regorafenib. We established a transcriptomic database for regorafenib-treated CCA cells using expression microarray chips. Our data indicate that regorafenib inhibits yes-associated protein 1 (YAP1) activity in various CCA cells. In addition, we demonstrated that YAP1 regulates epithelial-mesenchymal transition (EMT)-related genes, including E-cadherin and SNAI2. We further examined YAP1 activity, phosphorylation status, and expression levels of YAP1 downstream target genes in the regorafenib model. We found that regorafenib dramatically suppressed these events in CCA cells. Moreover, in vivo results revealed that regorafenib could significantly inhibit lung foci formation and tumorigenicity. Most importantly, regorafenib and amphiregulin (AREG) neutralize antibody exhibited synergistic effects against CCA cells. In a clinical setting, patients with high YAP1 and EMT expression had a worse survival rate than patients with low YAP1, and EMT expression did. In addition, we found that YAP1 upregulated the downstream target amphiregulin in CCA. Our findings suggest that AREG neutralizing antibody antibodies combined with regorafenib can reverse the CCA metastatic phenotype and EMT in vitro and in vivo. These findings provide novel therapeutic strategies to combat the metastasis of CCA.

SAMiRNA Targeting Amphiregulin Alleviate Total-Body-Irradiation-Induced Renal Fibrosis.

Fibrosis is a serious unintended side effect of radiation therapy. In this study, we aimed to investigate whether amphiregulin (AREG) plays a critical role in fibrosis development after total-body irradiation (TBI). We found that the expression of AREG and fibrotic markers, such as α-smooth muscle actin (α-SMA) and collagen type I alpha 1 (COL1α1), was elevated in the kidneys of 6 Gy TBI mice. Expression of AREG and α-SMA was mainly elevated in the proximal and distal tubules of the kidney in response to TBI, which was confirmed by immunofluorescence staining. Knockdown of Areg mRNA using self-assembled-micelle inhibitory RNA (SAMiRNA) significantly reduced the expression of fibrotic markers, including α-SMA and COL1α1, and inflammatory regulators. Finally, intravenous injections of SAMiRNA targeting mouse Areg mRNA (SAMiRNA-mAREG) diminished radiation-induced collagen accumulation in the renal cortex and medulla. Taken together, the results of the present study suggest that blocking of AREG signaling via SAMiRNA-mAREG treatment could be a promising therapeutic approach to alleviate radiation-induced kidney fibrosis.

Establishment of a patient-derived mucoepidermoid carcinoma cell line with the CRTC1-MAML2 fusion gene.

Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the major and minor salivary glands. Surgical resection is the only curative treatment and there is no effective post-operative therapy for MEC. The present study reports an Institutional Review Board-approved case of a 45-year-old Japanese female diagnosed with low-grade MEC in the hard palate. Radical resection, supraomohyoid neck dissection and antero-lateral thigh flap reconstruction was performed. A MEC cell line was then established from the resected tumor tissue. Short tandem repeat profiling confirmed the origin and authenticity of the cell line, that harbors a CRTC1-MAML2 translocation, which is frequently observed in MEC. Amphiregulin (AREG), identified as one of the targets of the CRTC1-MAML2 fusion gene, was expressed in the cell line. The AREG receptor, epidermal growth factor receptor (EGFR) was also highly phosphorylated. The results predicted that AREG-EGFR signaling, which is required for tumor growth and survival, might be activated in the cell line in a cell-autonomous manner. As AREG expression is associated with EGFR-targeted drug resistance, this cell line might assist with the identification of novel strategies for MEC treatment.

Left ventricular function is related with amphiregulin and fibrosis markers in cirrhotic cardiomyopathy.

The relationship between left ventricle (LV), extracellular matrix remodeling and fibrosis-linked amphiregulin (ARG) in cirrhotic cardiomyopathy (CCM) is unknown. The aim of the study was to investigate the associations between markers of extracellular matrix remodeling and ARG in cirrhosis and their association with indicators of ventricular remodeling and LV functional parameters. In hepatitis C virus (HCV) patients with cirrhosis, who underwent echocardiography, the presence of left ventricular diastolic dysfunction (LVDD) was determined by having gradable diastolic dysfunction in accordance with modified 2020 Cirrhotic Cardiomyopathy Consortium criteria. A total of 87 cirrhotic patients were consecutively analyzed. Based on detailed echocardiographic assessment - 35 HCV patients with cirrhosis had normal left ventricular diastolic function (non-CCM group), whereas 52 patients had LVDD (CCM group). ARG was measured by enzyme-linked immunosorbent assay. The ARG levels were significantly increased in the CCM group compared to the non-CCM group (P<0.001). ARG levels in all HCV patients were independently associated to the presence of CCM, and showed significant correlations with LVDD. The close relationship between ARG levels and the direct serum marker of fibrosis, and selected markers of extracellular matrix (i.e. transforming growth factor-beta1 (TGF-β1), and carboxyterminal propeptide of type I collagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP), tissue inhibitor of matrix proteinase-1 (TIMP-1), respectively), ventricular remodeling (i.e. N-terminal pro B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin-T (hs-TnT)), and LV functional parameters suggest an active role in the myocardial injury. Using ROC analysis, the best marker for the diagnosis of CCM was NT-proBNP with AUROC = 0.796. The area under the curve of ARG (AUROC = 0.709) for predicting CCM was greater than this for PICP (AUROC = 0.662) and similar to this hs-TnT (AUROC = 0.753). The simultaneous monitoring of serum ARG and markers of extracellular matrix and ventricular remodeling can be helpful for the alterations in myocardial function control in HCV patients with cirrhosis.

Cytokines secreted by mesenchymal stem cells reduce demyelination in an animal model of Charcot-Marie-Tooth disease

IntroductionDemyelinating Charcot-Marie-Tooth disease (CMT) is caused by mutations in the genes that encode myelinating proteins or their transcription factors. Our study thus sought to assess the therapeutic effects of cytokines secreted from mesenchymal stem cells (MSCs) on this disease. MethodsThe therapeutic potential of Wharton's jelly MSCs (WJ-MSCs) and cytokines secreted by WJ-MSCs was evaluated on Schwann cells (SCs) exhibiting demyelination features, as well as a mouse model of demyelinating CMT. ResultsCo-culture with WJ-MSC protected PMP22-overexpressing SCs from apoptotic cell death. Using a cytokine array, the secretion of growth differentiation factor-15 (GDF-15) and amphiregulin (AREG) was found to be elevated in WJ-MSCs when co-incubated with the PMP22-overexpressing SCs. Administration of both cytokines into trembler-J (Tr-J) mice, an animal model of CMT, significantly enhanced motor nerve conduction velocity compared to the control group. More importantly, this treatment alleviated the demyelinating phenotype of Tr-J mice, as demonstrated by an improvement in the mean diameter and g-ratio of the myelinated axons. ConclusionsOur findings demonstrated that WJ-MSCs alleviate the demyelinating phenotype of CMT via the secretion of several cytokines. Further elucidation of the underlying mechanisms of GDF-15 and AREG in myelination might provide a robust basis for the development of effective therapies against demyelinating CMT.

Influence of Anoctamin-4 and -9 on ADAM10 and ADAM17 Sheddase Function.

Ca2+-activated Cl− channels (TMEM16, also known as anoctamins) perform important functions in cell physiology, including modulation of cell proliferation and cancer growth. Many members, including TMEM16F/ANO6, additionally act as Ca2+-activated phospholipid scramblases. We recently presented evidence that ANO6-dependent surface exposure of phosphatidylserine (PS) is pivotal for the disintegrin-like metalloproteases ADAM10 and ADAM17 to exert their sheddase function. Here, we compared the influence of seven ANO family members (ANO1, 4, 5, 6, 7, 9, and 10) on ADAM sheddase activity. Similar to ANO6, overexpression of ANO4 and ANO9 led to increased release of ADAM10 and ADAM17 substrates, such as betacellulin, TGFα, and amphiregulin (AREG), upon ionophore stimulation in HEK cells. Inhibitor experiments indicated that ANO4/ANO9-mediated enhancement of TGFα-cleavage broadened the spectrum of participating metalloproteinases. Annexin V-staining demonstrated increased externalisation of PS in ANO4/ANO9-overexpressing cells. Competition experiments with the soluble PS-headgroup phosphorylserine indicated that the ANO4/ANO9 effects were due to increased PS exposure. Overexpression of ANO4 or ANO9 in human cervical cancer cells (HeLa), enhanced constitutive shedding of the growth factor AREG and increased cell proliferation. We conclude that ANO4 and ANO9, by virtue of their scramblase activity, may play a role as important regulators of ADAM-dependent cellular functions.

Interrelationships between amphiregulin, kisspeptin, FSH and FSH receptor in promotion of human ovarian cell functions.

The aim of this study was to investigate: (1) the ability of granulosa cells to produce amphiregulin (AREG), kisspeptin (KISS) and FSH receptor (FSHR); (2) the role of AREG and KISS in the control of ovarian functions; (3) the effect of FSH and KISS on AREG; and (4) the ability of KISS to affect FSHR and to modify FSH action on AREG output by human ovarian granulosa cells. We examined: (1) time-dependent accumulation of AREG; (2) effects of AREG (0, 1, 10, 100ng/mL) and KISS (0, 1, 10, 100ng/mL) on granulosa cell functions; and (3) the effects of KISS (0, 1, 10, 100ng/mL), FSH (0, 1, 10, 100ng/mL), and their combinations on AREG release. Viability, markers of proliferation [accumulation ofproliferating cell nuclear antigen (PCNA) cyclin B1 and sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy6-nitro)benzene sulfonic acid hydrate (XTT formazan)] and apoptosis (accumulation of bax, caspase 3 and terminal deoxynucleotidyl transferase dUTP nick-end labelling), accumulation of KISS, FSHR and steroid hormones, and AREG release were analysed by Trypan blue exclusion test, quantitative immunocytochemistry, XTT, terminal deoxynucleotidyl transferase dUTP nick-end labelling assays and enzyme-linked immunosorbent assay. AREG promoted cell viability, proliferation and steroid hormone output, and inhibited apoptosis. KISS (1 and 10ng/mL) stimulated viability, proliferation, steroid hormone release and occurrence of FSHR and suppressed apoptosis and AREG output; KISS (100ng/mL) had the opposite effect. FSH stimulated AREG release, whilst addition of KISS reversed this FSH effect. FSH mimicked and promoted the inhibitory effect of KISS on AREG release. These results suggest an intra-ovarian production and a functional interrelationship between AREG, KISS, FSH and FSHR in direct regulation of basic ovarian cell functions.

Effect of amphiregulin, neuregulin-i and tumour necrosis factor-a on growth of ovine preantral follicle and oocyte in vitro

A study was conducted to observe the effects of different concentrations and combination of amphiregulin (AREG)/neuregulin-I (NRG-I)/tumour necrosis factor-α (TNF- α) on the development of ovine preantral follicles (PFs) and oocyte enclosed in PFs. Totally 1589 PFs were isolated from 215 ovaries collected from civil slaughterhouse, Bengaluru. The PFs were cultured in 100 μl droplets of culture medium supplemented with different concentrations viz., 0 (control), 5, 10, 25, 50, 100 and 150 ng of either AREG or NRG-I or TNF-α and their optimum dose combination in a carbon dioxide incubator (38° C, 5% CO2 in air, 90 to 95% relative humidity). Significant (p<0.05) increase in the growth rate of PFs and oocytes were observed on culturing with AREG and NRG-I at 100 and 150 ng, TNF-α at 5 and 10 ng and with combination of AREG+NRG-I and AREG+NRG-I+TNF-α. It was concluded that addition of AREG (100ng), NRG-1 (100ng), TNF-α (10ng) and combinations of AREG+NRG-I and AREG+NRG-I+ TNF-α groups supported maximum growth of PFs and oocytes in-vitro.

Proteomic analysis of oocytes retrieved from in vitro cultured ovine small antral follicles and large antral follicles cultured with amphiregulin, neuregulin-1 and tumour necrosis factor-a

Protein components change markedly during follicular development in the ovary. In this study, a proteomics approach was used to evaluate changes in proteins during different size follicles viz small antral follicles (SAFs) and large antral follicles (LAFs) culture exposed with different growth factors. The optimum and elevated doses of amphiregulin (AREG) or neuregulin (NRG-I) or tumour necrosis factor-α (TNF-α) were used for culture of SAFs and LAFs and then oocytes were retrieved for analysis of secretory protein by SDS-PAGE. SAFs were cultured in media containing 150 ng of AREG, NRG1 and TNF-α and LAFs in media containing 50 ng of AREG, NRG1 and TNF-α. The average yield of protein from oocytes retrieved from SAFs when cultured with 150 ng of AREG, NRG-1 and TNF-α was 0.0012, 0.0016 and 0.0010 mg/ml respectively. When cultured with oocytes retrieved from LAFs in 50 ng AREG, 50 ng NRG-I and 50 ng TNF-α, the corresponding values were 0.0026, 0.0021 and 0.0014 mg/ml respectively. The SDS-PAGE profile of the oocytes retrieved from culturing of SAFs and LAFs in different doses of AREG, NRG-I and TNF-α revealed no peptide bands.

ADAM17, A Key Player of Cardiac Inflammation and Fibrosis in Heart Failure Development During Chronic Catecholamine Stress.

Heart failure development is characterized by persistent inflammation and progressive fibrosis owing to chronic catecholamine stress. In a chronic stress state, elevated catecholamines result in the overstimulation of beta-adrenergic receptors (βARs), specifically β2-AR coupling with Gαi protein. Gαi signaling increases the activation of receptor-stimulated p38 mitogen-activated-protein-kinases (p38 MAPKs) and extracellular signal-regulated kinases (ERKs). Phosphorylation by these kinases is a common way to positively regulate the catalytic activity of A Disintegrin and Metalloprotease 17 (ADAM17), a metalloprotease that has grown much attention in recent years and has emerged as a chief regulatory hub in inflammation, fibrosis, and immunity due to its vital proteolytic activity. ADAM17 cleaves and activates proinflammatory cytokines and fibrotic factors that enhance cardiac dysfunction via inflammation and fibrosis. However, there is limited information on the cardiovascular aspect of ADAM17, especially in heart failure. Hence, this concise review provides a comprehensive insight into the structure of ADAM17, how it is activated and regulated during chronic catecholamine stress in heart failure development. This review highlights the inflammatory and fibrotic roles of ADAM17’s substrates; Tumor Necrosis Factor α (TNFα), soluble interleukin-6 receptor (sIL-6R), and amphiregulin (AREG). Finally, how ADAM17-induced chronic inflammation and progressive fibrosis aggravate cardiac dysfunction is discussed.

Propofol induces apoptosis and ameliorates 5‑fluorouracil resistance in OSCC cells by reducing the expression and secretion of amphiregulin

Among the different types of oral cancer, >90% of cases are oral squamous cell carcinoma (OSCC). 5-fluorouracil (5-FU) is a commonly used treatment for OSCC, but cells typically display resistance to the drug. Propofol, an intravenous anesthetic agent, exhibits certain anticancer effects, including the inhibition of cancer cell proliferation, migration and invasion. Secreted proteins, such as growth factors and cytokines are involved in cancer development and progression, but the effect of propofol on secreted proteins in OSCC is not completely understood. An MTT assay, flow cytometry and western blotting were performed to determine the anticancer effects of propofol. The secretion profile of OSCC was determined using an antibody array, and clinical importance was assessed using the Gene Expression Profiling Interactive Analysis database. The results were verified by performing reverse transcription-quantitative PCR (RT-qPCR) and western blotting. 5-FU-resistant cells were established to determine the role of the gene of interest in drug resistance. The results demonstrated that propofol decreased cell viability and promoted cell apoptosis. The antibody array results showed that propofol attenuated the secretion of multiple growth factors. The bioinformatics results indicated that amphiregulin (AREG) was expressed at significantly higher levels in cancer tissues, which was also related to poor prognosis. The results of RT-qPCR and western blotting revealed that propofol decreased AREG expression. Pretreatment with exogenous recombinant AREG increased EGFR activation and conferred propofol resistance. Moreover, the results indicated that the expression and activation of AREG was also related to 5-FU resistance, but propofol ameliorated 5-FU drug resistance. Therefore, the present study suggested that propofol combination therapy may serve as an effective treatment strategy for OSCC.

Mitochondrial glutamine metabolism regulates sensitivity of cancer cells after chemotherapy via amphiregulin

The DNA damage response is essential for sustaining genomic stability and preventing tumorigenesis. However, the fundamental question about the cellular metabolic response to DNA damage remains largely unknown, impeding the development of metabolic interventions that might prevent or treat cancer. Recently, it has been reported that there is a link between cell metabolism and DNA damage response, by repression of glutamine (Gln) entry into mitochondria to support cell cycle arrest and DNA repair. Here, we show that mitochondrial Gln metabolism is a crucial regulator of DNA damage-induced cell death. Mechanistically, inhibition of glutaminase (GLS), the first enzyme for Gln anaplerosis, sensitizes cancer cells to DNA damage by inducing amphiregulin (AREG) that promotes apoptotic cell death. GLS inhibition increases reactive oxygen species production, leading to transcriptional activation of AREG through Max-like protein X (MLX) transcription factor. Moreover, suppression of mitochondrial Gln metabolism results in markedly increased cell death after chemotherapy in vitro and in vivo. The essentiality of this molecular pathway in DNA damage-induced cell death may provide novel metabolic interventions for cancer therapy.

Microglial-stimulation of glioma invasion involves the EGFR ligand amphiregulin.

High grade glioma is one of the deadliest human cancers with a median survival rate of only one year following diagnosis. The highly motile and invasive nature of high grade glioma makes it difficult to completely remove surgically. Therefore, increasing our knowledge of the mechanisms glioma cells use to invade normal brain is of critical importance in designing novel therapies. It was previously shown by our laboratory that tumor-associated microglia (TAMs) stimulate glioma cell invasion and this process is dependent on CSF-1R signaling. In this study, we seek to identify pro-invasive factors that are upregulated in microglia in a CSF-1R-dependent manner. We assayed cDNA and protein from microglia treated with conditioned media from the murine glioma cell line GL261, and discovered that several EGFR ligands including amphiregulin (AREG) are strongly upregulated. This upregulation is blocked by addition of a pharmacological CSF-1R inhibitor. Using RNA interference, we show that AREG-depleted microglia are less effective at promoting invasion of GL261 cells into Matrigel-coated invasion chambers. In addition, an AREG blocking antibody strongly attenuates the ability of THP-1 macrophages to activate human glioma cell line U87 invasion. Furthermore, we have identified a signaling pathway which involves CSF-1 signaling through ERK to upregulate AREG expression in microglia. Interfering with ERK using pharmacological inhibitors prevents AREG upregulation in microglia and microglia-stimulated GL261 invasion. These data highlight AREG as a key factor in produced by tumor associated microglia in promoting glioma invasion.

Dynamic Changes of AREG in the Sclera during the Development of Form-Deprivation Myopia in Guinea Pigs

ABSTRACTPurposeTo investigate amphiregulin (AREG) expression in the sclera during the development of form-deprivation myopia (FDM) and after the recovery of FDM in guinea pigs.MethodsSixty-four 2-week-old guinea pigs were randomly divided into the control and FDM groups. The right eyes of animals in FDM group were covered for 2 weeks (2 W) and 4 weeks (4 W), or were covered for 4 weeks and then uncovered for the subsequent 2 weeks (6 W). The diopters and axial lengths (AL) in the right eyes of guinea pigs were measured. Reverse transcription polymerase chain reaction (RT-PCR), immunofluorescence, and western blotting assays were used to detect the relative mRNA and protein expressions of AREG in the sclera of guinea pigs.ResultsBefore masking (0 W), the refraction and AL in the right eyes of guinea pigs in the control and FDM groups did not differ significantly (both p > .05). Myopic shift was induced in guinea pigs with the diopters gradually decreased and AL increased in the FDM group. While no significant difference was found in control group at different time points, the relative AREG mRNA and protein expression levels in the FDM group were significantly increased in 2 W and 4 W and then decreased after 4 weeks of covering followed by uncovering for 2 weeks (all p < .05).ConclusionsAREG was expressed in the sclera of guinea pigs. Moreover, the expression levels of AREG increased during the development of FDM and downregulated after recovery of FDM. Therefore, AREG may be involved in the regulation of scleral remodeling in myopia.