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Frontiers in Oncology 2021Non-small cell lung cancer (NSCLC) has high mortality rates worldwide. Agrin contributes to immune synapse information and is involved in tumor metastasis. However, its...
Non-small cell lung cancer (NSCLC) has high mortality rates worldwide. Agrin contributes to immune synapse information and is involved in tumor metastasis. However, its roles in NSCLC and tumor immune microenvironment remain unclear. This study examined the effects and the underlying mechanisms of Agrin in NSCLC and tumor-infiltrated immune cells. Clinical tissue samples were used to confirm the bioinformatic predictions. NSCLC cells were used to investigate the effects of Agrin on cell cycle and proliferation, as well as invasion and migration. Tumor xenograft mouse model was used to confirm the effects of Agrin on NSCLC growth and tumor-infiltrated regulatory T cells (Tregs) . Agrin levels in NSCLC cells were closely related to tumor progression and metastasis, and its function was enriched in the PI3K/AKT pathway. assays demonstrated that Agrin knockdown suppressed NSCLC cell proliferation and metastasis, while PI3K/AKT activators reversed the inhibitory effects of Agrin deficiency on NSCLC cell behaviors. Agrin expression was negatively associated with immunotherapy responses in NSCLC patients. Agrin knockdown suppressed Tregs, as well as interleukin (IL)-6 expression and secretion, while PI3K/AKT activators and exogenous IL-6 rescued the inhibitory effects. In the mouse model, Agrin downregulation alleviated NSCLC cell growth and Treg infiltration . Our results indicated that Agrin promotes tumor cell growth and Treg infiltration increasing IL-6 expression and secretion through PI3K/AKT pathway in NSCLC. Our studies suggested Agrin as a therapeutically potential target to increase the efficacy of immunotherapy in NSCLC patients.
PubMed: 35111682
DOI: 10.3389/fonc.2021.804418 -
Pharmacological Research Aug 2023Lung cancer is the main reason for cancer-associated death globally, and lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer. Recently, AGRN is...
Lung cancer is the main reason for cancer-associated death globally, and lung adenocarcinoma (LUAD) is the most prevalent subtype of lung cancer. Recently, AGRN is considered playing an vital role in the development of some cancers. However, the regulatory effects and mechanisms of AGRN in LUAD remain elusive. In this study, we clarified the significant upregulation of AGRN expression in LUAD by single-cell RNA sequencing combined with immunohistochemistry. Besides, we confirmed that LUAD patients with high AGRN expression are more susceptible to lymph node metastases and have a worse prognosis by a retrospective study of 120 LUAD patients. Next, we demonstrated that AGRN directly interact with NOTCH1, which results in the release of the intracellular structural domain of NOTCH1 and the subsequent activation of the NOTCH pathway. Moreover, we also found that AGRN promotes proliferation, migration, invasion, EMT and tumorigenesis of LUAD cells in vitro and in vivo, and that these effects are reversed by blocking the NOTCH pathway. Furthermore, we prepared several antibodies targeting AGRN, and clarify that Anti-AGRN antibody treatment could significantly inhibit proliferation and promote apoptosis of tumor cells. Our study highlights the important role and regulatory mechanism of AGRN in LUAD development and progression, and suggests that antibodies targeting AGRN have therapeutic potential for LUAD. We also provide theoretical and experimental evidence for further development of monoclonal antibodies targeting AGRN.
Topics: Humans; Adenocarcinoma of Lung; Cell Line, Tumor; Cell Movement; Cell Proliferation; Gene Expression Regulation, Neoplastic; Lung Neoplasms; Retrospective Studies; Signal Transduction; Agrin; Receptor, Notch1
PubMed: 37321467
DOI: 10.1016/j.phrs.2023.106819 -
The Journal of Biological Chemistry Aug 2023Collagen Q (ColQ) is a nonfibrillar collagen that plays a crucial role at the vertebrate neuromuscular junction (NMJ) by anchoring acetylcholinesterase to the synapse....
Collagen Q (ColQ) is a nonfibrillar collagen that plays a crucial role at the vertebrate neuromuscular junction (NMJ) by anchoring acetylcholinesterase to the synapse. ColQ also functions in signaling, as it regulates acetylcholine receptor clustering and synaptic gene expression, in a manner dependent on muscle-specific kinase (MuSK), a key protein in NMJ formation and maintenance. MuSK forms a complex with low-density lipoprotein receptor-related protein 4 (LRP4), its coreceptor for the proteoglycan agrin at the NMJ. Previous studies suggested that ColQ also interacts with MuSK. However, the molecular mechanisms underlying ColQ functions and ColQ-MuSK interaction have not been fully elucidated. Here, we investigated whether ColQ binds directly to MuSK and/or LRP4 and whether it modulates agrin-mediated MuSK-LRP4 activation. Using coimmunoprecipitation, pull-down, plate-binding assays, and surface plasmon resonance, we show that ColQ binds directly to LRP4 but not to MuSK and that ColQ interacts indirectly with MuSK through LRP4. In addition, we show that the LRP4 N-terminal region, which contains the agrin-binding sites, is also crucial for ColQ binding to LRP4. Moreover, ColQ-LRP4 interaction was reduced in the presence of agrin, suggesting that agrin and ColQ compete for binding to LRP4. Strikingly, we reveal ColQ has two opposing effects on agrin-induced MuSK-LRP4 signaling: it constitutively reduces MuSK phosphorylation levels in agrin-stimulated myotubes but concomitantly increases MuSK accumulation at the muscle cell surface. Our results identify LRP4 as a major receptor of ColQ and provide new insights into mechanisms of ColQ signaling and acetylcholinesterase anchoring at the NMJ.
Topics: Humans; Acetylcholinesterase; Agrin; Collagen; LDL-Receptor Related Proteins; Muscle Fibers, Skeletal; Neuromuscular Junction; Receptor Protein-Tyrosine Kinases
PubMed: 37356721
DOI: 10.1016/j.jbc.2023.104962 -
Cancers Feb 2018In addition to the structural and scaffolding role, the extracellular matrix (ECM) is emerging as a hub for biomechanical signal transduction that is frequently relayed... (Review)
Review
In addition to the structural and scaffolding role, the extracellular matrix (ECM) is emerging as a hub for biomechanical signal transduction that is frequently relayed to intracellular sensors to regulate diverse cellular processes. At a macroscopic scale, matrix rigidity confers long-ranging effects contributing towards tissue fibrosis and cancer. The transcriptional co-activators YAP/TAZ, better known as the converging effectors of the Hippo pathway, are widely recognized for their new role as nuclear mechanosensors during organ homeostasis and cancer. Still, how YAP/TAZ senses these "stiffness cues" from the ECM remains enigmatic. Here, we highlight the recent perspectives on the role of agrin in mechanosignaling from the ECM via antagonizing the Hippo pathway to activate YAP/TAZ in the contexts of cancer, neuromuscular junctions, and cardiac regeneration.
PubMed: 29415512
DOI: 10.3390/cancers10020045 -
International Journal of Molecular... Oct 2022Neuronal agrin, a heparan sulphate proteoglycan secreted by the α-motor neurons, promotes the formation and maintenance of the neuromuscular junction by binding to Lrp4...
Neuronal agrin, a heparan sulphate proteoglycan secreted by the α-motor neurons, promotes the formation and maintenance of the neuromuscular junction by binding to Lrp4 and activating muscle-specific kinase (MuSK). Neuronal agrin also promotes myogenesis by enhancing differentiation and maturation of myotubes, but its effect on proliferating human myoblasts, which are often considered to be unresponsive to agrin, remains unclear. Using primary human myoblasts, we determined that neuronal agrin induced transient dephosphorylation of ERK1/2, while c-Abl, STAT3, and focal adhesion kinase were unresponsive. Gene silencing of Lrp4 and MuSK markedly reduced the BrdU incorporation, suggesting the functional importance of the Lrp4/MuSK complex for myoblast proliferation. Acute and chronic treatments with neuronal agrin increased the proliferation of human myoblasts in old donors, but they did not affect the proliferation of myoblasts in young donors. The C-terminal fragment of agrin which lacks the Lrp4-binding site and cannot activate MuSK had a similar age-dependent effect, indicating that the age-dependent signalling pathways activated by neuronal agrin involve the Lrp4/MuSK receptor complex as well as an Lrp4/MuSK-independent pathway which remained unknown. Collectively, our results highlight an age-dependent role for neuronal agrin in promoting the proliferation of human myoblasts.
Topics: Age Factors; Agrin; Bromodeoxyuridine; Cell Proliferation; Focal Adhesion Protein-Tyrosine Kinases; Heparan Sulfate Proteoglycans; Humans; LDL-Receptor Related Proteins; Motor Neurons; Myoblasts; Receptor Protein-Tyrosine Kinases
PubMed: 36233091
DOI: 10.3390/ijms231911784 -
Frontiers in Bioengineering and... 2020After cardiac injury, the mammalian adult heart has a very limited capacity to regenerate, due to the inability of fully differentiated cardiomyocytes (CMs) to...
After cardiac injury, the mammalian adult heart has a very limited capacity to regenerate, due to the inability of fully differentiated cardiomyocytes (CMs) to efficiently proliferate. This has been directly linked to the extracellular matrix (ECM) surrounding and connecting cardiomyocytes, as its increasing rigidity during heart maturation has a crucial impact over the proliferative capacity of CMs. Very recent studies using mouse models have demonstrated how the ECM protein agrin might promote heart regeneration through CMs de-differentiation and proliferation. In maturing CMs, this proteoglycan would act as an inducer of a specific molecular pathway involving ECM receptor(s) within the transmembrane dystrophin-glycoprotein complex (DGC) as well as intracellular Yap, an effector of the Hippo pathway involved in the replication/regeneration program of CMs. According to the mechanism proposed, during mice heart development agrin gets progressively downregulated and ultimately replaced by other ECM proteins eventually leading to loss of proliferation/ regenerative capacity in mature CMs. Although the role played by the agrin-DGC-YAP axis during human heart development remains still largely to be defined, this scenario opens up fascinating and promising therapeutic avenues. Herein, we discuss the currently available relevant information on this system, with a view to explore how the fundamental understanding of the regenerative potential of this cellular program can be translated into therapeutic treatment of injured human hearts.
PubMed: 32612983
DOI: 10.3389/fbioe.2020.00594 -
Frontiers in Cell and Developmental... 2020Botulinum neurotoxin (BoNT) has become a powerful therapeutic tool, and is extensively used in aesthetic medicine and in the treatment of neurological disorders....
Botulinum neurotoxin (BoNT) has become a powerful therapeutic tool, and is extensively used in aesthetic medicine and in the treatment of neurological disorders. However, its duration of effect is limited, mainly owing to nerve sprouting. Inhibition of nerve sprouting to prolong the effective duration of BoNT is therefore of great clinical interest. However, appropriate interventional strategies to accomplish this are currently unavailable. In this study, we determined the role of the neurogenic regulator agrin in BoNT type A (BoNT/A)-induced nerve sprouting in a rat model. We then determined whether agrin could be used as an interventional target for prolonging the duration of effect of BoNT/A, and made a preliminary study of the upstream and downstream regulatory mechanisms by which agrin could influence the effective duration of BoNT/A. Our results showed that agrin was involved in the regulation of BoNT/A-induced nerve sprouting, and blocking of agrin function with anti-agrin antibody temporarily could delay muscle strength recovery and prolong the duration of BoNT/A effect. Moreover, agrin influenced the duration of BoNT/A effect by regulating downstream myogenic muscle-specific receptor tyrosine kinase (MuSK), and was simultaneously regulated by upstream miR-144. In conclusion, agrin could regulate BoNT/A-induced nerve sprouting through miR-144-agrin-MuSK signaling; it influences the effective duration of BoNT/A, and could find clinical application as an interventional target for prolonging the effect of BoNT/A.
PubMed: 32083076
DOI: 10.3389/fcell.2020.00015 -
European Journal of Biochemistry Oct 1999Synapses are essential relay stations for the transmission of information between neurones and other cells. An ordered and tightly regulated formation of these... (Review)
Review
Synapses are essential relay stations for the transmission of information between neurones and other cells. An ordered and tightly regulated formation of these structures is crucial for the functioning of the nervous system. The induction of the intensively studied synapse between nerve and muscle is initiated by the binding of neurone-specific isoforms of the basal membrane protein agrin to receptors on the surface of myotubes. Agrin activates a receptor complex that includes the muscle-specific kinase and most likely additional, yet to be identified, components. Receptor activation leads to the aggregation of acetylcholine receptors (AChR) and other proteins of the postsynaptic apparatus. This activation process has unique features which distinguish it from other receptor tyrosine kinases. In particular, the autophosphorylation of the kinase domain, which usually induces the recruitment of adaptor and signalling molecules, is not sufficient for AChR aggregation. Apparently, interactions of the extracellular domain with unknown components are also required for this process. Agrin binds to a second protein complex on the muscle surface known as the dystrophin-associated glycoprotein complex. This binding forms one end of a molecular link between the extracellular matrix and the cytoskeleton. While many components of the machinery triggering postsynaptic differentiation have now been identified, our picture of the molecular pathway causing the redistribution of synaptic proteins is still incomplete.
Topics: Agrin; Cell Communication; Cytoskeletal Proteins; Dystroglycans; Membrane Glycoproteins; Motor Neurons; Muscle Proteins; Neuromuscular Junction; Protein Isoforms; Receptor Protein-Tyrosine Kinases; Receptors, Cholinergic; Receptors, Growth Factor
PubMed: 10491152
DOI: 10.1046/j.1432-1327.1999.00765.x -
The American Journal of Pathology May 2000The dystrophin-glycoprotein complex, which comprises alpha- and beta-dystroglycan, sarcoglycans, and utrophin/dystrophin, links the cytoskeleton to agrin and laminin in...
The dystrophin-glycoprotein complex, which comprises alpha- and beta-dystroglycan, sarcoglycans, and utrophin/dystrophin, links the cytoskeleton to agrin and laminin in the basal lamina in muscle and epithelial cells. Recently, agrin was identified as a major heparan sulfate proteoglycan in the glomerular basement membrane. In the present study, we found mRNA expression for agrin, dystroglycan, and utrophin in kidney cortex, isolated glomeruli, and cultured podocytes and mesangial cells. In immunofluorescence, agrin was found in the glomerular basement membrane. The antibodies against alpha- and beta-dystroglycan and utrophin revealed a granular podocyte-like staining pattern along the glomerular capillary wall. With immunoelectron microscopy, agrin was found in the glomerular basement membrane, dystroglycan was diffusely found over the entire cell surface of the podocytes, and utrophin was localized in the cytoplasm of the podocyte foot processes. In adriamycin nephropathy, a decrease in the glomerular capillary wall staining for dystroglycan was observed probably secondary to the extensive fusion of foot processes. Immunoelectron microscopy showed a different distribution pattern as compared to the normal kidney, with segmentally enhanced expression of dystroglycan at the basal side of the extensively fused podocyte foot processes. In passive Heymann nephritis we observed no changes in the staining intensity and distribution of the dystrophin-glycoprotein complex by immunofluorescence and immunoelectron microscopy. From these data, we conclude that agrin, dystroglycan, and utrophin are present in the glomerular capillary wall and their ultrastructural localization supports the concept that these molecules are involved in linking the podocyte cytoskeleton to the glomerular basement membrane.
Topics: Agrin; Animals; Cytoskeletal Proteins; Doxorubicin; Dystroglycans; Gene Expression; Glomerular Mesangium; Glomerulonephritis; Immunohistochemistry; Kidney; Kidney Cortex; Kidney Glomerulus; Male; Membrane Glycoproteins; Membrane Proteins; Microscopy, Immunoelectron; Nephrotic Syndrome; RNA, Messenger; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Utrophin
PubMed: 10793086
DOI: 10.1016/S0002-9440(10)65046-8 -
PloS One 2014Oral squamous cell carcinoma is the most common type of cancer in the oral cavity, representing more than 90% of all oral cancers. The characterization of altered...
Oral squamous cell carcinoma is the most common type of cancer in the oral cavity, representing more than 90% of all oral cancers. The characterization of altered molecules in oral cancer is essential to understand molecular mechanisms underlying tumor progression as well as to contribute to cancer biomarker and therapeutic target discovery. Proteoglycans are key molecular effectors of cell surface and pericellular microenvironments, performing multiple functions in cancer. Two of the major basement membrane proteoglycans, agrin and perlecan, were investigated in this study regarding their role in oral cancer. Using real time quantitative PCR (qRT-PCR), we showed that agrin and perlecan are highly expressed in oral squamous cell carcinoma. Interestingly, cell lines originated from distinct sites showed different expression of agrin and perlecan. Enzymatically targeting chondroitin sulfate modification by chondroitinase, oral squamous carcinoma cell line had a reduced ability to adhere to extracellular matrix proteins and increased sensibility to cisplatin. Additionally, knockdown of agrin and perlecan promoted a decrease on cell migration and adhesion, and on resistance of cells to cisplatin. Our study showed, for the first time, a negative regulation on oral cancer-associated events by either targeting chondroitin sulfate content or agrin and perlecan levels.
Topics: Agrin; Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cisplatin; Drug Resistance, Neoplasm; Gene Expression; Gene Knockdown Techniques; Heparan Sulfate Proteoglycans; Humans; Mouth Neoplasms
PubMed: 25506919
DOI: 10.1371/journal.pone.0115004