Role of glypican-1 in regulating multiple cellular signaling pathways

Pan-cancer analysis and the oncogenic role of Glypican 1 in hepatocellular carcinoma

Recent studies indicate that Glypican 1 (GPC-1) is aberrantly expressed and plays a key role in certain cancers, but little is known in the hepatocellular carcinoma. Raw data from TCGA, GTEx and TIMER databases were utilized to comprehensively analyze GPC-1 expression landscape in pan-cancer, and the biological function of GPC-1 was investigated in liver cancer cells. The results revealed that GPC-1 is highly expressed in HCC, negatively correlated with survival, and also positively correlated with immune infiltration and clinical stage. Furthermore, GPC-1 promoted cell proliferation and inhibited apoptosis in the HCC cell lines. WGCNA analysis and HCCDB database revealed that Akt acted as a key molecule related to GPC-1, influencing biological functions and regulating cell malignant behaviors via the AKT signaling pathway. In conclusion, our findings provide a relatively comprehensive understanding of the oncogenic role of GPC-1 in HCC, implying that GPC-1 could serve as an innovative therapeutic target.

LMNA -Related Dilated Cardiomyopathy: Single-Cell Transcriptomics during Patient-derived iPSC Differentiation Support Cell type and Lineage-specific Dysregulation of Gene Expression and Development for Cardiomyocytes and Epicardium-Derived Cells with Lamin A/C Haploinsufficiency

LMNA -Related Dilated Cardiomyopathy (DCM) is an autosomal-dominant genetic condition with cardiomyocyte and conduction system dysfunction often resulting in heart failure or sudden death. The condition is caused by mutation in the Lamin A/C ( LMNA ) gene encoding Type-A nuclear lamin proteins involved in nuclear integrity, epigenetic regulation of gene expression, and differentiation. Molecular mechanisms of disease are not completely understood, and there are no definitive treatments to reverse progression or prevent mortality. We investigated possible mechanisms of LMNA -Related DCM using induced pluripotent stem cells derived from a family with a heterozygous LMNA c.357-2A>G splice-site mutation. We differentiated one LMNA mutant iPSC line derived from an affected female (Patient) and two non-mutant iPSC lines derived from her unaffected sister (Control) and conducted single-cell RNA sequencing for 12 samples (4 Patient and 8 Control) across seven time points: Day 0, 2, 4, 9, 16, 19, and 30. Our bioinformatics workflow identified 125,554 cells in raw data and 110,521 (88%) high-quality cells in sequentially processed data. Unsupervised clustering, cell annotation, and trajectory inference found complex heterogeneity: ten main cell types; many possible subtypes; and lineage bifurcation for Cardiac Progenitors to Cardiomyocytes (CM) and Epicardium-Derived Cells (EPDC). Data integration and comparative analyses of Patient and Control cells found cell type and lineage differentially expressed genes (DEG) with enrichment to support pathway dysregulation. Top DEG and enriched pathways included: 10 ZNF genes and RNA polymerase II transcription in Pluripotent cells (PP); BMP4 and TGF Beta/BMP signaling, sarcomere gene subsets and cardiogenesis, CDH2 and EMT in CM; LMNA and epigenetic regulation and DDIT4 and mTORC1 signaling in EPDC. Top DEG also included: XIST and other X-linked genes, six imprinted genes: SNRPN , PWAR6 , NDN , PEG10 , MEG3 , MEG8 , and enriched gene sets in metabolism, proliferation, and homeostasis. We confirmed Lamin A/C haploinsufficiency by allelic expression and Western blot. Our complex Patient-derived iPSC model for Lamin A/C haploinsufficiency in PP, CM, and EPDC provided support for dysregulation of genes and pathways, many previously associated with Lamin A/C defects, such as epigenetic gene expression, signaling, and differentiation. Our findings support disruption of epigenomic developmental programs as proposed in other LMNA disease models. We recognized other factors influencing epigenetics and differentiation; thus, our approach needs improvement to further investigate this mechanism in an iPSC-derived model.

Exploring the properties and potential of the neural extracellular matrix for next-generation regenerative therapies

The extracellular matrix (ECM) is a dynamic and complex network of proteins and molecules that surrounds cells and tissues in the nervous system and orchestrates a myriad of biological functions. This review carefully examines the diverse interactions between cells and the ECM, as well as the transformative chemical and physical changes that the ECM undergoes during neural development, aging, and disease. These transformations play a pivotal role in shaping tissue morphogenesis and neural activity, thereby influencing the functionality of the central nervous system (CNS). In our comprehensive review, we describe the diverse behaviors of the CNS ECM in different physiological and pathological scenarios and explore the unique properties that make ECM-based strategies attractive for CNS repair and regeneration. Addressing the challenges of scalability, variability, and integration with host tissues, we review how advanced natural, synthetic, and combinatorial matrix approaches enhance biocompatibility, mechanical properties, and functional recovery. Overall, this review highlights the potential of decellularized ECM as a powerful tool for CNS modeling and regenerative purposes and sets the stage for future research in this exciting field. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

Hippo cell signaling and HS-proteoglycans regulate tissue form and function, age-dependent maturation, extracellular matrix remodeling, and repair

This review examined how Hippo cell signaling and heparan sulfate (HS)-proteoglycans (HSPGs) regulate tissue form and function. Despite being a nonweight-bearing tissue, the brain is regulated by Hippo mechanoresponsive cell signaling pathways during embryonic development. HS-proteoglycans interact with growth factors, morphogens, and extracellular matrix components to regulate development and pathology. Pikachurin and Eyes shut (Eys) interact with dystroglycan to stabilize the photoreceptor axoneme primary cilium and ribbon synapse facilitating phototransduction and neurotransduction with bipolar retinal neuronal networks in ocular vision, the primary human sense. Another HSPG, Neurexin interacts with structural and adaptor proteins to stabilize synapses and ensure specificity of neural interactions, and aids in synaptic potentiation and plasticity in neurotransduction. HSPGs also stabilize the blood-brain barrier and motor neuron basal structures in the neuromuscular junction. Agrin and perlecan localize acetylcholinesterase and its receptors in the neuromuscular junction essential for neuromuscular control. The primary cilium is a mechanosensory hub on neurons, utilized by YES associated protein (YAP)-transcriptional coactivator with PDZ-binding motif (TAZ) Hippo, Hh, Wnt, transforming growth factor (TGF)-β/bone matrix protein (BMP) receptor tyrosine kinase cell signaling. Members of the glypican HSPG proteoglycan family interact with Smoothened and Patched G-protein coupled receptors on the cilium to regulate Hh and Wnt signaling during neuronal development. Control of glycosyl sulfotransferases and endogenous protease expression by Hippo TAZ YAP represents a mechanism whereby the fine structure of HS-proteoglycans can be potentially modulated spatiotemporally to regulate tissue morphogenesis in a similar manner to how Hippo signaling controls sialyltransferase expression and mediation of cell-cell recognition, dysfunctional sialic acid expression is a feature of many tumors.

Control of tissue homeostasis by the extracellular matrix: Synthetic heparan sulfate as a promising therapeutic for periodontal health and bone regeneration

Proteoglycans are core proteins associated with carbohydrate/sugar moieties that are highly variable in disaccharide composition, which dictates their function. These carbohydrates are named glycosaminoglycans, and they can be attached to proteoglycans or found free in tissues or on cell surfaces. Glycosaminoglycans such as hyaluronan, chondroitin sulfate, dermatan sulfate, keratan sulfate, and heparin/heparan sulfate have multiple functions including involvement in inflammation, immunity and connective tissue structure, and integrity. Heparan sulfate is a highly sulfated polysaccharide that is abundant in the periodontium including alveolar bone. Recent evidence supports the contention that heparan sulfate is an important player in modulating interactions between damage associated molecular patterns and inflammatory receptors expressed by various cell types. The structure of heparan sulfate is reported to dictate its function, thus, the utilization of a homogenous and structurally defined heparan sulfate polysaccharide for modulation of cell function offers therapeutic potential. Recently, a chemoenzymatic approach was developed to allow production of many structurally defined heparan sulfate carbohydrates. These oligosaccharides have been studied in various pathological inflammatory conditions to better understand their function and their potential application in promoting tissue homeostasis. We have observed that specific size and sulfation patterns can modulate inflammation and promote tissue maintenance including an anabolic effect in alveolar bone. Thus, new evidence provides a strong impetus to explore heparan sulfate as a potential novel therapeutic agent to treat periodontitis, support alveolar bone maintenance, and promote bone formation.

Immuno-PET and Targeted α-Therapy Using Anti-Glypican-1 Antibody Labeled with 89Zr or 211At: A Theranostic Approach for Pancreatic Ductal Adenocarcinoma

Glypican-1 (GPC1) is overexpressed in several solid cancers and is associated with tumor progression, whereas its expression is low in normal tissues. This study aimed to evaluate the potential of an anti-GPC1 monoclonal antibody (GPC1 mAb) labeled with 89Zr or 211At as a theranostic target in pancreatic ductal adenocarcinoma. Methods: GPC1 mAb clone 01a033 was labeled with 89Zr or 211At with a deferoxamine or decaborane linker, respectively. The internalization ability of GPC1 mAb was evaluated by fluorescence conjugation using a confocal microscope. PANC-1 xenograft mice (n = 6) were intravenously administered [89Zr]GPC1 mAb (0.91 ± 0.10 MBq), and PET/CT scanning was performed for 7 d. Uptake specificity was confirmed through a comparative study using GPC1-positive (BxPC-3) and GPC1-negative (BxPC-3 GPC1-knockout) xenografts (each n = 3) and a blocking study. DNA double-strand breaks were evaluated using the γH2AX antibody. The antitumor effect was evaluated by administering [211At]GPC1 mAb (∼100 kBq) to PANC-1 xenograft mice (n = 10). Results: GPC1 mAb clone 01a033 showed increased internalization ratios over time. One day after administration, a high accumulation of [89Zr]GPC1 mAb was observed in the PANC-1 xenograft (SUVmax, 3.85 ± 0.10), which gradually decreased until day 7 (SUVmax, 2.16 ± 0.30). The uptake in the BxPC-3 xenograft was significantly higher than in the BxPC-3 GPC1-knockout xenograft (SUVmax, 4.66 ± 0.40 and 2.36 ± 0.36, respectively; P = 0.05). The uptake was significantly inhibited in the blocking group compared with the nonblocking group (percentage injected dose per gram, 7.3 ± 1.3 and 12.4 ± 3.0, respectively; P = 0.05). DNA double-strand breaks were observed by adding 150 kBq of [211At]GPC1 and were significantly suppressed by the internalization inhibitor (dynasore), suggesting a substantial contribution of the internalization ability to the antitumor effect. Tumor growth suppression was observed in PANC-1 mice after the administration of [211At]GPC1 mAb. Internalization inhibitors (prochlorperazine) significantly inhibited the therapeutic effect of [211At]GPC1 mAb, suggesting an essential role in targeted α-therapy. Conclusion: [89Zr]GPC1 mAb PET showed high tumoral uptake in the early phase after administration, and targeted α-therapy using [211At]GPC1 mAb showed tumor growth suppression. GPC1 is a promising target for future applications for the precise diagnosis of pancreatic ductal adenocarcinoma and GPC1-targeted theranostics.

APC and P53 mutations synergise to create a therapeutic vulnerability to NOTUM inhibition in advanced colorectal cancer

OBJECTIVE

Colorectal cancer (CRC) is a leading cause of cancer-related deaths, with the majority of cases initiated by inactivation of the APC tumour suppressor. This results in the constitutive activation of canonical WNT pathway transcriptional effector ß-catenin, along with induction of WNT feedback inhibitors, including the extracellular palmitoleoyl-protein carboxylesterase NOTUM which antagonises WNT-FZD receptor-ligand interactions. Here, we sought to evaluate the effects of NOTUM activity on CRC as a function of driver mutation landscape.

DESIGN

Mouse and human colon organoids engineered with combinations of CRC driver mutations were used for Notum genetic gain-of-function and loss-of-function studies. In vitro assays, in vivo endoscope-guided orthotopic organoid implantation assays and transcriptomic profiling were employed to characterise the effects of Notum activity. Small molecule inhibitors of Notum activity were used in preclinical therapeutic proof-of-principle studies targeting oncogenic Notum activity.

RESULTS

NOTUM retains tumour suppressive activity in APC-null adenomas despite constitutive ß-catenin activity. Strikingly, on progression to adenocarcinoma with P53 loss, NOTUM becomes an obligate oncogene. These phenotypes are Wnt-independent, resulting from differential activity of NOTUM on glypican 1 and 4 in early-stage versus late-stage disease, respectively. Ultimately, preclinical mouse models and human organoid cultures demonstrate that pharmacological inhibition of NOTUM is highly effective in arresting primary adenocarcinoma growth and inhibiting metastatic colonisation of distal organs.

CONCLUSIONS

Our findings that a single agent targeting the extracellular enzyme NOTUM is effective in treating highly aggressive, metastatic adenocarcinomas in preclinical mouse models and human organoids make NOTUM and its glypican targets therapeutic vulnerabilities in advanced CRC.

Global impact of proteoglycan science on human diseases

In this comprehensive review, we will dissect the impact of research on proteoglycans focusing on recent developments involved in their synthesis, degradation, and interactions, while critically assessing their usefulness in various biological processes. The emerging roles of proteoglycans in global infections, specifically the SARS-CoV-2 pandemic, and their rising functions in regenerative medicine and biomaterial science have significantly affected our current view of proteoglycans and related compounds. The roles of proteoglycans in cancer biology and their potential use as a next-generation protein-based adjuvant therapy to combat cancer is also emerging as a constructive and potentially beneficial therapeutic strategy. We will discuss the role of proteoglycans in selected and emerging areas of proteoglycan science, such as neurodegenerative diseases, autophagy, angiogenesis, cancer, infections and their impact on mammalian diseases.

The Glycosaminoglycan Side Chains and Modular Core Proteins of Heparan Sulphate Proteoglycans and the Varied Ways They Provide Tissue Protection by Regulating Physiological Processes and Cellular Behaviour

This review examines the roles of HS-proteoglycans (HS-PGs) in general, and, in particular, perlecan and syndecan as representative examples and their interactive ligands, which regulate physiological processes and cellular behavior in health and disease. HS-PGs are essential for the functional properties of tissues both in development and in the extracellular matrix (ECM) remodeling that occurs in response to trauma or disease. HS-PGs interact with a biodiverse range of chemokines, chemokine receptors, protease inhibitors, and growth factors in immune regulation, inflammation, ECM stabilization, and tissue protection. Some cell regulatory proteoglycan receptors are dually modified hybrid HS/CS proteoglycans (betaglycan, CD47). Neurexins provide synaptic stabilization, plasticity, and specificity of interaction, promoting neurotransduction, neurogenesis, and differentiation. Ternary complexes of glypican-1 and Robbo-Slit neuroregulatory proteins direct axonogenesis and neural network formation. Specific neurexin-neuroligin complexes stabilize synaptic interactions and neural activity. Disruption in these interactions leads to neurological deficits in disorders of functional cognitive decline. Interactions with HS-PGs also promote or inhibit tumor development. Thus, HS-PGs have complex and diverse regulatory roles in the physiological processes that regulate cellular behavior and the functional properties of normal and pathological tissues. Specialized HS-PGs, such as the neurexins, pikachurin, and Eyes-shut, provide synaptic stabilization and specificity of neural transduction and also stabilize the axenome primary cilium of phototoreceptors and ribbon synapse interactions with bipolar neurons of retinal neural networks, which are essential in ocular vision. Pikachurin and Eyes-Shut interactions with an α-dystroglycan stabilize the photoreceptor synapse. Novel regulatory roles for HS-PGs controlling cell behavior and tissue function are expected to continue to be uncovered in this fascinating class of proteoglycan.

Silencing Glypican-1 enhances the antitumor effects of Pictilisib via downregulating PI3K/Akt/ERK signaling in chemo-resistant esophageal adenocarcinoma

Poorly differentiated esophageal adenocarcinoma (PDEAC) has a dismal prognosis. Glypican-1(GPC-1) is known to be upregulated in several cancer types in contrast to healthy tissues, rendering it as a biomarker. Nevertheless, the potential therapeutic targeting of GPC-1 has not been explored in PDEAC. There is accumulating evidence that GPC-1, via upregulation of PI3K/Akt/ERK signaling, plays a crucial role in the progression and chemoresistance in cancer. Pictilisib, a class I pan PI3K inhibitor, has shown promising antitumor results in clinical trials, however, has not gained widespread success due to acquired drug resistance. This study investigated the role of GPC-1 in chemo-resistant PDEAC and appraises the impact of targeted silencing of GPC-1 on the antitumor effects of Pictilisib in PDEAC cell lines. Immunohistochemistry assays in PDEAC tissue specimens demonstrated a pronounced intensity of staining with GPC-1. Upregulation of GPC-1 was found to be correlated with advanced stage and poor prognosis. In-vitro studies examined the influence of GPC-1 knockdown and Pictilisib, both as individual agents and in combination, on cytotoxicity, cell cycle distribution, apoptosis, and gene expression profiles. Silencing GPC-1 alone showed significantly reduced cell viability, migration, colony formation, epithelial-mesenchymal transition, and stemness in PDEAC cells. Significantly, knockdown of GPC-1 combined with low-dose Pictilisib led to enhancement of cytotoxicity, cell cycle arrest, and apoptosis in ESO-26 and OE-33 cells. In the xenograft mouse model, the combination of Pictilisib and GPC-1 knockdown exhibited synergy. These findings suggest that GPC-1 represents a promising target to augment chemosensitivity in esophageal adenocarcinoma.

Glypican1: a potential cancer biomarker for nanotargeted therapy

Glypicans (GPCs) are generally involved in cellular signaling, growth and proliferation. Previous studies reported their roles in cancer proliferation. GPC1 is a co-receptor for a variety of growth-related ligands, thereby stimulating the tumor microenvironment by promoting angiogenesis and epithelial-mesenchymal transition (EMT). This work reviews GPC1-biomarker-assisted drug discovery by the application of nanostructured materials, creating nanotheragnostics for targeted delivery and application in liquid biopsies. The review includes details of GPC1 as a potential biomarker in cancer progression as well as a potential candidate for nano-mediated drug discovery.

Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Spatiotemporal Localisation of Heparan Sulphate Proteoglycans throughout Mouse Lens Morphogenesis

Heparan sulphate proteoglycans (HSPGs) consist of a core protein decorated with sulphated HS-glycosaminoglycan (GAG) chains. These negatively charged HS-GAG chains rely on the activity of PAPSS synthesising enzymes for their sulfation, which allows them to bind to and regulate the activity of many positively charged HS-binding proteins. HSPGs are found on the surfaces of cells and in the pericellular matrix, where they interact with various components of the cell microenvironment, including growth factors. By binding to and regulating ocular morphogens and growth factors, HSPGs are positioned to orchestrate growth factor-mediated signalling events that are essential for lens epithelial cell proliferation, migration, and lens fibre differentiation. Previous studies have shown that HS sulfation is essential for lens development. Moreover, each of the full-time HSPGs, differentiated by thirteen different core proteins, are differentially localised in a cell-type specific manner with regional differences in the postnatal rat lens. Here, the same thirteen HSPG-associated GAGs and core proteins as well as PAPSS2, are shown to be differentially regulated throughout murine lens development in a spatiotemporal manner. These findings suggest that HS-GAG sulfation is essential for growth factor-induced cellular processes during embryogenesis, and the unique and divergent localisation of different lens HSPG core proteins indicates that different HSPGs likely play specialized roles during lens induction and morphogenesis.

Attenuation of cancer proliferation by suppression of glypican-1 and its pleiotropic effects in neoplastic behavior

Glypicans (GPC1-6) are associated with tumorigenic processes and their involvement in neoplastic behavior has been discussed in different cancer types. Here, a cancer-wide GPC expression study, using clinical cancer patient data in The Cancer Genome Atlas, reveals net upregulation of GPC1 and GPC2 in primary solid tumors, whereas GPC3, GPC5 and GPC6 display lowered expression pattern compared to normal tissues. Focusing on GPC1, survival analyses of the clinical cancer patient data reveal statistically significant correlation between high expression of GPC1 and poor prognosis in 10 particular cancer types i.e., bladder urothelial carcinoma, brain lower grade glioma, liver hepatocellular carcinoma, colon adenocarcinoma, kidney renal clear cell carcinoma, lung adenocarcinoma, mesothelioma, ovarian serous cystadenocarcinoma, uterine corpus endometrial carcinoma and uveal melanoma. In vitro studies targeting GPC1 expression by CRISPR/Cas9 or siRNA or treatment with an anti-GPC1 antibody resulted in attenuation of proliferation of cancer cells from bladder carcinoma, glioma and hepatocellular carcinoma patients (T24, U87 and HepG2 cells). Further, overexpression of GPC1 exhibited a significant and negative correlation between GPC1 expression and proliferation of T24 cells. Attempt to reveal the mechanism through which downregulation of GPC1 leads to attenuation of tumor growth using systematic Ingenuity Pathway Analysis indicate that suppression of GPC1 results in ECM-mediated inhibition of specific pro-cancer signaling pathways involving TGF-β and p38 MAPK. Identified differential expression and pleiotropic effects of GPCs in specific cancer types emphasize their potential of as novel diagnostic tools and prognostic factors and open doors for future GPC targeted therapy.

Human collecting lymphatic glycocalyx identification by electron microscopy and immunohistochemistry

Blood flow is translated into biochemical inflammatory or anti-inflammatory signals based onshear stress type, by means of sensitive endothelial receptors. Recognition of the phenomenon is of paramount importance for enhanced insights into the pathophysiological processes of vascular remodeling. The endothelial glycocalyx is a pericellular matrix, identified in both arteries and veins, acting collectively as a sensor responsive to blood flow changes. Venous and lymphatic physiology is interconnected; however, to our knowledge, a lymphatic glycocalyx structure has never been identified in humans. The objective of this investigation is to identify glycocalyx structures from ex vivo lymphatic human samples. Lower limb vein and lymphatic vessels were harvested. The samples were analyzed by transmission electron microscopy. The specimens were also examined by immunohistochemistry. Transmission electron microscopy identified a glycocalyx structure in human venous and lymphatic samples. Immunohistochemistry for podoplanin, glypican-1, mucin-2, agrin and brevican characterized lymphatic and venous glycocalyx-like structures. To our knowledge, the present work reports the first identification of a glycocalyx-like structure in human lymphatic tissue. The vasculoprotective action of the glycocalyx could become an investigational target in the lymphatic system as well, with clinical implications for the many patients affected by lymphatic disorders.

HS, an Ancient Molecular Recognition and Information Storage Glycosaminoglycan, Equips HS-Proteoglycans with Diverse Matrix and Cell-Interactive Properties Operative in Tissue Development and Tissue Function in Health and Disease

Heparan sulfate is a ubiquitous, variably sulfated interactive glycosaminoglycan that consists of repeating disaccharides of glucuronic acid and glucosamine that are subject to a number of modifications (acetylation, de-acetylation, epimerization, sulfation). Variable heparan sulfate chain lengths and sequences within the heparan sulfate chains provide structural diversity generating interactive oligosaccharide binding motifs with a diverse range of extracellular ligands and cellular receptors providing instructional cues over cellular behaviour and tissue homeostasis through the regulation of essential physiological processes in development, health, and disease. heparan sulfate and heparan sulfate-PGs are integral components of the specialized glycocalyx surrounding cells. Heparan sulfate is the most heterogeneous glycosaminoglycan, in terms of its sequence and biosynthetic modifications making it a difficult molecule to fully characterize, multiple ligands also make an elucidation of heparan sulfate functional properties complicated. Spatio-temporal presentation of heparan sulfate sulfate groups is an important functional determinant in tissue development and in cellular control of wound healing and extracellular remodelling in pathological tissues. The regulatory properties of heparan sulfate are mediated via interactions with chemokines, chemokine receptors, growth factors and morphogens in cell proliferation, differentiation, development, tissue remodelling, wound healing, immune regulation, inflammation, and tumour development. A greater understanding of these HS interactive processes will improve therapeutic procedures and prognoses. Advances in glycosaminoglycan synthesis and sequencing, computational analytical carbohydrate algorithms and advanced software for the evaluation of molecular docking of heparan sulfate with its molecular partners are now available. These advanced analytic techniques and artificial intelligence offer predictive capability in the elucidation of heparan sulfate conformational effects on heparan sulfate-ligand interactions significantly aiding heparan sulfate therapeutics development.

Trajectory of plasma syndecan-1 and heparan sulphate during major surgery: A retrospective observational study

BACKGROUND

Surgical trauma-induced inflammation during major surgery may disrupt endothelial integrity and affect plasma concentrations of glycocalyx constituents, such as syndecan-1 and heparan sulphate. To date, no studies have focused on their perioperative temporal changes.

METHODS

As part of a trial, we obtained plasma and urine specimens sampled during the perioperative period in 72 patients undergoing major abdominal surgery. The plasma concentration of syndecan-1 and heparan sulphate was measured on five occasions, from baseline to the second postoperative day. Plasma and urinary creatinine and urinary syndecan-1 concentrations were measured before surgery and on the first postoperative morning.

RESULTS

We observed three different temporal patterns of plasma syndecan-1 concentration. Group 1 'low' (64% of patients) showed only minor changes from baseline despite a median heparan sulphate increase of 67% (p < .005). Group 2 'increase' (21% of patients) showed a marked increase in median plasma syndecan-1 from 27 μg/L to 118 μg/L during the first postoperative day (p < .001) with a substantial (+670%; p < .005) increase in median plasma heparan sulphate from 279 to 2196 μg/L. Group 3 'high' (14% of patients) showed a constant elevation of plasma syndecan-1 to >100 μg/L, but low heparan sulphate levels. The plasma C-reactive protein concentration did not differ across the three groups and 90% of colon surgeries occurred in Group 1. Treatment with dexamethasone was similar across the three groups. Surgical blood loss, duration of surgery and liver resection were greatest in Group 2.

CONCLUSION

Changes in syndecan-1 and heparan sulphate after surgery appear to show three different patterns, with the greatest increases in those patients with greater blood loss, more liver surgery and longer operations. These observations suggest that increases in syndecan-1 and heparan sulphate reflect the degree of surgical injury.

Serum exosomal and serum glypican-1 are associated with early recurrence of pancreatic ductal adenocarcinoma

Background

The diagnostic performance and prognostic value of serum exosomal glypican 1 (GPC-1) in pancreatic ductal adenocarcinoma (PDAC) remain controversial. In this study, we detected serum exosomal GPC-1 using enzyme-linked immunosorbent assay (ELISA) and determined whether it serves as a predictor of diagnosis and recurrence for early-stage PDAC.

Methods

Serum samples were obtained from patients with 50 PDAC, 6 benign pancreatic tumor (BPT), or 9 chronic pancreatitis (CP) and 50 healthy controls (HCs). Serum exosomes were isolated using an exosome isolation kit. Exosomal and serum GPC-1 levels were measured using ELISA. The freeze–thaw process was carried out to analyze the stability of GPC-1. Receiver operating characteristic (ROC) analysis was employed to assess the diagnostic value of GPC-1. Kaplan–Meier and multivariate Cox analyses were used to evaluate the prognostic value of GPC-1.

Results

The average concentrations of serum exosomal and serum GPC-1 were 1.5 and 0.8 ng/ml, respectively. GPC-1 expression levels were stable under repeated freezing and thawing (d1-5 freeze–thaw cycles vs. d0 P > 0.05). Serum exosomal and serum GPC-1 were significantly elevated in patients with PDAC compared with HCs (P < 0.0001) but were slightly higher compared with that in patients with CP and BPT (P > 0.05). The expression levels of exosomal and serum GPC-1 were elevated 5 days after surgery in patients with PDAC, CP, and BPT (P < 0.05). Patients with high levels of exosomal and serum GPC-1 had a shorter relapse-free survival (RFS) (P = 0.006, and P = 0.010). Multivariate analyses showed that serum exosomal and serum GPC-1 were independent prognostic indicators for early RFS (P = 0.008, and P = 0.041).

Conclusion

ELISA is an effective and sensitive method to detect exosomal and serum GPC-1. The detection of GPC-1 was stable under repeated freezing and thawing cycles and could distinguish early-stage PDAC from HCs but not CP and BPT. Exosomal and serum GPC-1 may be good independent predictors of early recurrence in early-stage PDAC.

Inactivation of BACE1 increases expression of endothelial nitric oxide synthase in cerebrovascular endothelium

Cerebrovascular effects of β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) inactivation have not been systematically studied. In the present study we employed cultured human brain microvascular endothelial cells (BMECs), BACE1-knockout (BACE1^-/-) mice and conditional (tamoxifen-induced) endothelium-specific BACE1-knockout (eBACE1^-/-) mice to determine effect of BACE1 inhibition on expression and function of endothelial nitric oxide synthase (eNOS). Deletion of BACE1 caused upregulation of eNOS and glypican-1 (GPC1) in human BMECs treated with BACE1-siRNA, and cerebral microvessels of male BACE1^-/- mice and male eBACE1^-/- mice. In addition, BACE1siRNA treatment increased NO production in human BMECs. These effects appeared to be independent of amyloid β-peptide production. Furthermore, adenoviral-mediated overexpression of BACE1 in human BMECs down-regulated GPC1 and eNOS. Treatment of human BMECs with GPC1siRNA suppressed mRNA and protein levels of eNOS. In basilar arteries of male eBACE1^-/- mice, endothelium-dependent relaxations to acetylcholine and endothelium-independent relaxations to NO donor, DEA-NONOate, were not affected, consistent with unchanged expression of eNOS and phosphorylation of eNOS at Ser1177 in large cerebral arteries. In aggregate, our findings suggest that under physiological conditions, inactivation of endothelial BACE1 increases expression of eNOS in cerebral microvessels but not in large brain arteries. This effect appears to be mediated by increased GPC1 expression.

Excavating proteoglycan structure-function relationships: Modern approaches to capture the interactions of ancient biomolecules

Proteoglycans are now well regarded as key facilitators of cell biology. While a majority of their interactions and functions are attributed to the decorating glycosaminoglycan chains, there is a growing appreciation for the roles of the proteoglycan core protein and for considering proteoglycans as replete protein-glycan conjugates. This appreciation, seeded by early work in proteoglycan biology, is now being advanced and exalted by modern approaches in chemical glycobiology. In this review, we discuss up-and-coming methods to unearth the fine-scale architecture of proteoglycans that modulate their functions and interactions. Crucial to these efforts is the production of chemically defined materials, including semi-synthetic proteoglycans and the in situ capture of interacting proteins. Together, the integration of chemical biology approaches promises to expedite the dissection of the structural heterogeneity of proteoglycans and deliver refined insight into their functions.

The structure of EXTL3 helps to explain the different roles of bi-domain exostosins in heparan sulfate synthesis

Heparan sulfate is a highly modified O-linked glycan that performs diverse physiological roles in animal tissues. Though quickly modified, it is initially synthesised as a polysaccharide of alternating β-D-glucuronosyl and N-acetyl-α-D-glucosaminyl residues by exostosins. These enzymes generally possess two glycosyltransferase domains (GT47 and GT64)-each thought to add one type of monosaccharide unit to the backbone. Although previous structures of murine exostosin-like 2 (EXTL2) provide insight into the GT64 domain, the rest of the bi-domain architecture is yet to be characterised; hence, how the two domains co-operate is unknown. Here, we report the structure of human exostosin-like 3 (EXTL3) in apo and UDP-bound forms. We explain the ineffectiveness of EXTL3's GT47 domain to transfer β-D-glucuronosyl units, and we observe that, in general, the bi-domain architecture would preclude a processive mechanism of backbone extension. We therefore propose that heparan sulfate backbone polymerisation occurs by a simple dissociative mechanism.

GPC1-Targeted Immunotoxins Inhibit Pancreatic Tumor Growth in Mice via Depletion of Short-lived GPC1 and Downregulation of Wnt Signaling

Glypican-1 (GPC1) is a cell surface proteoglycan that is upregulated in multiple types of human cancers including pancreatic cancer. Here, we investigated whether GPC1 could be a target of antibody-toxin fusion proteins (i.e., immunotoxins) for treating pancreatic cancer. We constructed a panel of GPC1-targeted immunotoxins derived from a functional domain of Pseudomonas exotoxin A. An albumin-binding domain was also introduced into the anti-GPC1 immunotoxin to improve serum half-life. Small-molecule screening was performed to identify irinotecan that shows synergistic efficacy with the immunotoxin. We showed that GPC1 was internalized upon antibody binding. Anti-GPC1 immunotoxins alone inhibited tumor growth in a pancreatic cancer xenograft model. The immunotoxin treatment reduced active β-catenin expression in tumor cells. Furthermore, immunotoxins containing an albumin-binding domain in combination with irinotecan caused pancreatic tumor regression. GPC1 expression was reduced by the immunotoxin treatment due to the degradation of the internalized GPC1 and its short cellular turnover rate. Our data indicate that the GPC1-targeted immunotoxin inhibits pancreatic tumor growth via degradation of internalized GPC1, downregulation of Wnt signaling, and inhibition of protein synthesis. The anti-GPC1 immunotoxin in combination with irinotecan thus provides a potential new treatment strategy for patients with pancreatic tumors.

Unconventional secretion mediated by direct protein self-translocation across the plasma membranes of mammalian cells

In recent years, a surprisingly complex picture emerged about endoplasmic reticulum (ER)/Golgi-independent secretory pathways, and several routes have been discovered that differ with regard to their molecular mechanisms and machineries. Fibroblast growth factor 2 (FGF2) is secreted by a pathway of unconventional protein secretion (UPS) that is based on direct self-translocation across the plasma membrane. Building on previous research, a component of this process has been identified to be glypican-1 (GPC1), a GPI-anchored heparan sulfate proteoglycan located on cell surfaces. These findings not only shed light on the molecular mechanism underlying this process but also reveal an intimate relationship between FGF2 and GPC1 that might be of critical relevance for the prominent roles they both have in tumor progression and metastasis.

Glypican-1 drives unconventional secretion of Fibroblast Growth Factor 2

Fibroblast Growth Factor 2 (FGF2) is a tumor cell survival factor that is transported into the extracellular space by an unconventional secretory mechanism. Cell surface heparan sulfate proteoglycans are known to play an essential role in this process. Unexpectedly, we found that among the diverse sub-classes consisting of syndecans, perlecans, glypicans and others, Glypican-1 (GPC1) is the principle and rate-limiting factor that drives unconventional secretion of FGF2. By contrast, we demonstrate GPC1 to be dispensable for FGF2 signaling into cells. We provide first insights into the structural basis for GPC1-dependent FGF2 secretion, identifying disaccharides with N-linked sulfate groups to be enriched in the heparan sulfate chains of GPC1 to which FGF2 binds with high affinity. Our findings have broad implications for the role of GPC1 as a key molecule in tumor progression.

Coreceptor Functions of Cell Surface Heparan Sulfate Proteoglycans

Receptor-ligand interactions play an important role in many biological processes by triggering specific cellular responses. These interactions are frequently regulated by coreceptors that facilitate, alter, or inhibit signaling. Coreceptors work in parallel with other specific and accessory molecules to coordinate receptor-ligand interactions. Cell surface heparan sulfate proteoglycans (HSPGs) function as unique coreceptors because they can bind to many ligands and receptors through their HS and core protein motifs. Cell surface HSPGs are typically expressed in abundance of the signaling receptors and, thus, are capable of mediating the initial binding of ligands to the cell surface. HSPG coreceptors do not possess kinase domains or intrinsic enzyme activities and, for the most part, binding to cell surface HSPGs does not directly stimulate intracellular signaling. Because of these features, cell surface HSPGs primarily function as coreceptors for many receptor-ligand interactions. Given that cell surface HSPGs are widely conserved, they likely serve fundamental functions to preserve basic physiological processes. Indeed, cell surface HSPGs can support specific cellular interactions with growth factors, morphogens, chemokines, extracellular matrix (ECM) components, and microbial pathogens and their secreted virulence factors. Through these interactions, HSPG coreceptors regulate cell adhesion, proliferation, migration and differentiation, and impact the onset, progression, and outcome of pathophysiological processes, such as development, tissue repair, inflammation, infection, and tumorigenesis. This review seeks to provide an overview of the various mechanisms of how cell surface HSPGs function as coreceptors.

The microRNA-cell surface proteoglycan axis in cancer progression

Proteoglycans consist one of the major extracellular matrix class of biomolecules that demonstrate nodal roles in cancer progression. Μodern diagnostic and therapeutic approaches include proteoglycan detection and pharmacological targeting in various cancers. Proteoglycans orchestrate critical signaling pathways for cancer development and progression through dynamic interactions with matrix components. It is well established that the epigenetic signatures of cancer cells play critical role in guiding their functional properties and metastatic potential. Secreted microRNAs (miRNAs) reside in a complex network with matrix proteoglycans, thus affecting cell-cell and cell-matrix communication. This mini-review aims to highlight current knowledge on the proteoglycan-mediated signaling cascades that regulate miRNA biogenesis in cancer. Moreover, the miRNA-mediated proteoglycan regulation during cancer progression and mechanistic aspects on the way that proteoglycans affect miRNA expression are presented. Recent advances on the role of cell surface proteoglycans in exosome biogenesis and miRNA packaging and expression are also discussed.

The function of Glypicans in the mammalian embryo

Glypicans are proteoglycans that are bound to the outer surface of the plasma membrane by a glycosylphosphatidylinositol anchor. The mammalian genome contains six members of the glypican family (GPC1 to GPC6). Although the degree of sequence homology within the family is rather low, the three-dimensional structure of these proteoglycans is highly conserved. Glypicans are predominantly expressed during embryonic development. Genetic and biochemical studies have shown that glypicans can stimulate or inhibit the signaling pathways triggered by Wnts, Hedgehogs, Fibroblast Growth Factors, and Bone Morphogenetic Proteins. The study of mutant mouse strains demonstrated that glypicans have important functions in the developmental morphogenesis of various organs. In addition, a role of glypicans in synapsis formation has been established. Notably, glypican loss-of-function mutations are the cause of three human inherited syndromes. Recent analysis of glypican compound mutant mice have demonstrated that members of this protein family display redundant functions during embryonic development.

Genetic Factors and Their Role in the Pathogenesis of Biliary Atresia

Biliary Atresia, a common basis for neonatal cholestasis and primary indication for Liver Transplantation, accounts for 60% of pediatric Liver Transplantations. While the pathogenesis of Biliary Atresia remains obscure, abnormalities within bile ducts and the liver, inflammation, fibrosis and cilia defects are thought to comprise the pathological basis for this condition. The findings of genetic variants in Biliary Atresia, such as Copy Number Variations and Single Nucleotide Polymorphism, are considered as essential factors in the development of this condition. In this review, we summarize and analyze these Biliary Atresia variants from a perspective of their pathological characteristics. In conclusion, such analyses may offer novel insights into the pathogenesis of Biliary Atresia and provide a foundation for future studies directed toward a better understanding and treatment of Biliary Atresia.