Leucine-rich alpha-2-glycoprotein-1 is upregulated in sera and tumors of ovarian cancer patients

Evaluation of Serum Proteome Sample Preparation Methods to Support Clinical Proteomics Applications

Serum contains several proteins that are associated with disease-related processes. Mass spectrometry (MS)-based proteomics approaches greatly facilitate serum protein biomarker development. However, the serum proteome complexity presents a technical challenge for the accurate, sensitive, and reproducible quantification of proteins by MS. Thus, efficient sample preparation methods are of critical importance for serum proteome analyses. In this study, we evaluated the technical performance of two serum proteome sample preparation methods using sera from patients with high-grade serous ovarian cancer and patients with benign nongynecological conditions with a goal of providing insight into their compatibility with clinical proteomics workflows. One method entailed the use of immobilized trypsin (SMART Digest Trypsin) with RapiGest SF, an acid-labile surfactant designed to enhance the in-solution enzymatic digestion of proteins. The other method incorporated a commercially available sample preparation kit, iST-BCT, which contains standardized reagents. Significantly higher protein sequence coverage, albeit with lower digestion efficiency, was obtained with the immobilized trypsin + RapiGest SF workflow, whereas the iST-BCT workflow was quicker and had marginally better reproducibility. Protein relative abundance analysis revealed that the serum proteomes clustered primarily by the sample processing workflow and secondarily by disease state. We conducted a time course study to determine whether differences in the relative abundance of diagnostic high-grade serous ovarian cancer serum protein biomarker candidates were biased according to the duration of enzymatic digestion. Our results highlight the importance of optimizing enzymatic digestion kinetics according to the peptide targets of interest while considering the sensitivity of the downstream analytical method utilized in clinical proteomics workflows designed to measure biomarkers.

Cross-Sectional and Longitudinal Associations of Serum LRG1 with Severity and Prognosis Among Adult Community-Acquired Pneumonia Patients

Background

Leucine-rich α-2 glycoprotein 1 (LRG1) is associated with various inflammatory lung diseases. Nevertheless, the connection between LRG1 and adult community-acquired pneumonia (CAP) individuals was still not well understood. Through a prospective cohort study, the correlations of serum LRG1 with severity and prognosis were evaluated in CAP patients.

Methods

The study encompassed 327 patients who received the diagnosis of CAP. We collected fasting venous blood and clinical features. Serum LRG1 was detected by ELISA. CAP severity was assessed using various scoring systems. The prognostic outcomes were observed through follow-up visits.

Results

The level of serum LRG1 at admission was gradually increased with CAP severity scores. Serum LRG1 level shown positive associations with inflammatory indices, including C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6). Linear and logistic regression analyses suggested that serum LRG1 at admission was positively associated with severity scores and the risk of death in CAP patients. Serum LRG1 in combination with CAP severity scores significantly increased the predictive powers for severity and death compared with single serum LRG1 or severity scores.

Conclusion

The study revealed positive connections of serum LRG1 levels with severity and poor prognosis in CAP patients, suggesting LRG1 partakes into the physiological processes of CAP. Serum LRG1 may be regarded as a potential biomarker in predicting the severity and death among CAP patients.

LRG1 and SDR16C5 protein expressions differ according to HPV status in oropharyngeal squamous cell carcinoma

The increasing incidence of oropharyngeal squamous cell carcinoma (OPSCC) is primarily due to human papillomavirus, and understanding the tumor biology caused by the virus is crucial. Our goal was to investigate the proteins present in the serum of patients with OPSCC, which were not previously studied in OPSCC tissue. We examined the difference in expression of these proteins between HPV-positive and -negative tumors and their correlation with clinicopathological parameters and patient survival. The study included 157 formalin-fixed, paraffin-embedded tissue samples and clinicopathological data. Based on the protein levels in the sera of OPSCC patients, we selected 12 proteins and studied their expression in HPV-negative and HPV-positive OPSCC cell lines. LRG1, SDR16C5, PIP4K2C and MVD proteins were selected for immunohistochemical analysis in HPV-positive and -negative OPSCC tissue samples. These protein´s expression levels were compared with clinicopathological parameters and patient survival to investigate their clinical relevance. LRG1 expression was strong in HPV-negative whereas SDR16C5 expression was strong in HPV-positive tumors. Correlation was observed between LRG1, SDR16C5, and PIP4K2C expression and patient survival. High expression of PIP4K2C was found to be an independent prognostic factor for overall survival and expression correlated with HPV-positive tumor status. The data suggest the possible role of LRG1, SDR16C5 and PIP4K2C in OPSCC biology.

High serum levels of leucine-rich α-2 glycoprotein 1 (LRG-1) are associated with poor survival in patients with early breast cancer

BACKGROUND

Leucine-rich α-2 glycoprotein 1 (LRG-1) is a secreted glycoprotein that is mainly produced in the liver. Elevated levels of LRG-1 are found in a multitude of pathological conditions including eye diseases, diabetes, infections, autoimmune diseases, and cancer. In patients with early breast cancer (BC), high intratumoral LRG-1 protein expression levels are associated with reduced survival. In this study, we assessed serum levels of LRG-1 in patients with early BC and investigated its correlation with the presence of disseminated tumor cells (DTCs) in the bone marrow and survival outcomes.

METHODS

Serum LRG-1 levels of 509 BC patients were determined using ELISA and DTCs were assessed by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3. We stratified LRG-1 levels according to selected clinical parameters. Using the log-rank (Mantel-Cox) test and multivariate Cox regression analysis, Kaplan-Meier survival curves and prognostic relevance were assessed.

RESULTS

Mean serum levels of LRG-1 were 29.70 ± 8.67 µg/ml. Age was positively correlated with LRG-1 expression (r = 0.19; p < 0.0001) and significantly higher LRG-1 levels were found in patients over 60 years compared to younger ones (30.49 ± 8.63 µg/ml vs. 28.85 ± 8.63 µg/ml; p = 0.011) and in postmenopausal patients compared to premenopausal patients (30.15 ± 8.34 µg/ml vs. 26.936.94 µg/ml; p = 0.002). Patients with no DTCs showed significantly elevated LRG-1 levels compared to the DTC-positive group (30.51 ± 8.69 µg/ml vs. 28.51 ± 8.54 µg/ml; p = 0.004). Overall and BC-specific survival was significantly lower in patients with high serum LRG-1 levels (above a cut-off of 33.63 µg/ml) compared to patients with lower LRG-1 levels during a mean follow-up of 8.5 years (24.8% vs. 11.1% BC-specific death; p = 0.0003; odds ratio 2.63, 95%CI: 1.56-4.36). Multivariate analyses revealed that LRG-1 is an independent prognostic marker for BC-specific survival (p = 0.001; hazard ratio 2.61).

CONCLUSIONS

This study highlights the potential of LRG-1 as an independent prognostic biomarker in patients with early BC.

The disruptive role of LRG1 on the vasculature and perivascular microenvironment

The establishment of new blood vessels, and their subsequent stabilization, is a critical process that facilitates tissue growth and organ development. Once established, vessels need to diversify to meet the specific needs of the local tissue and to maintain homeostasis. These processes are tightly regulated and fundamental to normal vessel and tissue function. The mechanisms that orchestrate angiogenesis and vessel maturation have been widely studied, with signaling crosstalk between endothelium and perivascular cells being identified as an essential component. In disease, however, new vessels develop abnormally, and existing vessels lose their specialization and function, which invariably contributes to disease progression. Despite considerable research into the vasculopathic mechanisms in disease, our knowledge remains incomplete. Accordingly, the identification of angiocrine and angiopathic molecules secreted by cells within the vascular microenvironment, and their effect on vessel behaviour, remains a major research objective. Over the last decade the secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1), has emerged as a significant vasculopathic molecule, stimulating defective angiogenesis, and destabilizing the existing vasculature mainly, but not uniquely, by altering both canonical and non-canonical TGF-β signaling in a highly cell and context dependent manner. Whilst LRG1 does not possess any overt homeostatic role in vessel development and maintenance, growing evidence provides a compelling case for LRG1 playing a pleiotropic role in disrupting the vasculature in many disease settings. Thus, LRG1 has now been reported to damage vessels in various disorders including cancer, diabetes, chronic kidney disease, ocular disease, and lung disease and the signaling processes that drive this dysfunction are being defined. Moreover, therapeutic targeting of LRG1 has been widely proposed to re-establish a quiescent endothelium and normalized vasculature. In this review, we consider the current status of our understanding of the role of LRG1 in vascular pathology, and its potential as a therapeutic target.

Increased level of serum leucine-rich-alpha-2-glycoprotein 1 in patients with clear cell renal cell carcinoma

BACKGROUND

Currently, no useful serum markers exist for clear cell renal cell carcinoma (ccRCC), making early detection challenging as diagnosis relies solely on imaging tests. Radiation exposure is also a concern due to multiple required CT examinations during treatment. Renal cell carcinoma (RCC) histological types include ccRCC and non-clear cell RCC (non-ccRCC); however, treatment response to medications varies which necessitates accurate differentiation between the two. Therefore, we aimed to identify a novel serum marker of RCC. Increased LRG1 expression in the serum has been demonstrated in multiple cancer types. However, the expression of LRG1 expression in the serum and cancer tissues of patients with RCC has not been reported. Since ccRCC is a hypervascular tumor and LRG1 is capable of accelerating angiogenesis, we hypothesized that the LRG1 levels may be related to ccRCC. Therefore, we examined LRG1 expression in sera from patients with RCC.

METHODS

Using an enzyme-linked immunosorbent assay, serum levels of leucine-rich-alpha-2-glycoprotein 1 (LRG1) were measured in 64 patients with ccRCC and 22 patients non-ccRCC who underwent radical or partial nephrectomy, as well as in 63 patients without cancer.

RESULTS

Median values of serum LRG1 and their inter-quartile ranges were 63.2 (42.8-94.2) µg/mL in ccRCC, 23.4 (17.7-29.6) µg/mL in non-ccRCC, and 36.0 (23.7-56.7) µg/mL in patients without cancer, respectively (ccRCC vs. non-ccRCC or patients without cancer: P < 0.001). C-reactive protein (CRP) levels (P = 0.002), anemia (P = 0.037), hypercalcemia (P = 0.023), and grade (P = 0.031) were independent predictors of serum LRG1 levels in ccRCC. To assess diagnostic performance, the area under the receiver operating characteristic curve of serum LRG1 was utilized to differentiate ccRCC from non-cancer and non-ccRCC, with values of 0.73 (95% CI, 0.64-0.82) and 0.91 (95% CI, 0.82-0.96), respectively.

CONCLUSIONS

LRG1 served as a serum marker associated with inflammation, indicated by CRP, anemia, hypercalcemia, and malignant potential in ccRCC. Clinically, serum LRG1 levels may assist in differentiating ccRCC from non-ccRCC with excellent diagnostic accuracy.

Advancements in protein glycosylation biomarkers for ovarian cancer through mass spectrometry-based approaches

INTRODUCTION

Ovarian cancer, characterized by metastasis and reduced 5-year survival rates, stands as a substantial factor in the mortality of gynecological malignancies worldwide. The challenge of delayed diagnosis originates from vague early symptoms and the absence of efficient screening and diagnostic biomarkers for early cancer detection. Recent studies have explored the intricate interplay between ovarian cancer and protein glycosylation, unveiling the potential significance of glycosylation-oriented biomarkers.

AREAS COVERED

This review examines the progress in glycosylation biomarker research, with particular emphasis on advances driven by mass spectrometry-based technologies. We document milestones achieved, discuss encountered limitations, and also highlight potential areas for future research and development of protein glycosylation biomarkers for ovarian cancer.

EXPERT OPINION

The association of glycosylation in ovarian cancer is well known, but current research lacks desired sensitivity and specificity for early detection. Notably, investigations into protein-specific and site-specific glycoproteomics have the potential to significantly enhance our understanding of ovarian cancer and facilitate the identification of glycosylation-based biomarkers. Furthermore, the integration of advanced mass spectrometry techniques with AI-driven analysis and glycome databases holds the promise for revolutionizing biomarker discovery for ovarian cancer, ultimately transforming diagnosis and improving patient outcomes.

Increased expression of leucine-rich α-2 glycoprotein 1 as a predictive biomarker of favorable progression-free survival in meningioma

Most meningiomas, which are frequent central nervous system tumors, are classified as World Health Organization (WHO) grade 1 because of their slow-growing nature. However, the recurrence rate varies and is difficult to predict using conventional histopathological diagnoses. Leucine-rich α-2 glycoprotein 1 (LRG1) is involved in cell signal transduction, cell adhesion, and DNA repair and is a predictive biomarker in different malignant tumors; however, such a relationship has not been reported in meningiomas. We examined tissue microarrays of histological samples from 117 patients with grade 1 and 2 meningiomas and assessed their clinical and pathological features, including expression of LRG1 protein. LRG1-high meningiomas showed an increased number of vessels with CD3-positive cell infiltration (P = 0.0328) as well as higher CD105-positive vessels (P = 0.0084), as compared to LRG1-low cases. They also demonstrated better progression-free survival (hazard ratio [HR] 0.11, 95% confidence interval [CI] 0.016-0.841) compared to LRG1-low patients (P = 0.033). Moreover, multivariate analysis indicated that high LRG1 expression was an independent prognostic factor (HR, 0.13; 95% CI, 0.018-0.991; P = 0.049). LRG1 immunohistochemistry may be a convenient tool for estimating the prognosis of meningiomas in routine practice. Further studies are required to elucidate the key role of LRG1 in meningioma progression.

Integrated Transcriptomics-Proteomics Analysis Identifies Molecular Phenotypic Alterations Associated with Colorectal Cancer

Understanding the pathogenesis and finding diagnostic markers for colorectal cancer (CRC) are the key to its diagnosis and treatment. Integrated transcriptomics and proteomics analysis can be used to characterize alterations of molecular phenotypes and reveal the hidden pathogenesis of CRC. This study employed a novel strategy integrating transcriptomics and proteomics to identify pathological molecular pathways and diagnostic biomarkers of CRC. First, differentially expressed proteins and coexpressed genes generated from weighted gene coexpression network analysis (WGCNA) were intersected to obtain key genes of the CRC phenotype. In total, 63 key genes were identified, and pathway enrichment analysis showed that the process of coagulation and peptidase regulator activity could both play important roles in the development of CRC. Second, protein-protein interaction analysis was then conducted on these key genes to find the central genes involved in the metabolic pathways underpinning CRC. Finally, Itih3 and Lrg1 were further screened out as diagnostic biomarkers of CRC by applying statistical analysis on central genes combining transcriptomics and proteomics data. The deep involvement of central genes in tumorigenesis demonstrates the accuracy and reliability of this novel transcriptomics-proteomics integration strategy in biomarker discovery. The identified candidate biomarkers and enriched metabolic pathways provide insights for CRC diagnosis and treatment.

Quantification of putative ovarian cancer serum protein biomarkers using a multiplexed targeted mass spectrometry assay

BACKGROUND

Ovarian cancer is the most lethal gynecologic malignancy in women, and high-grade serous ovarian cancer (HGSOC) is the most common subtype. Currently, no clinical test has been approved by the FDA to screen the general population for ovarian cancer. This underscores the critical need for the development of a robust methodology combined with novel technology to detect diagnostic biomarkers for HGSOC in the sera of women. Targeted mass spectrometry (MS) can be used to identify and quantify specific peptides/proteins in complex biological samples with high accuracy, sensitivity, and reproducibility. In this study, we sought to develop and conduct analytical validation of a multiplexed Tier 2 targeted MS parallel reaction monitoring (PRM) assay for the relative quantification of 23 putative ovarian cancer protein biomarkers in sera.

METHODS

To develop a PRM method for our target peptides in sera, we followed nationally recognized consensus guidelines for validating fit-for-purpose Tier 2 targeted MS assays. The endogenous target peptide concentrations were calculated using the calibration curves in serum for each target peptide. Receiver operating characteristic (ROC) curves were analyzed to evaluate the diagnostic performance of the biomarker candidates.

RESULTS

We describe an effort to develop and analytically validate a multiplexed Tier 2 targeted PRM MS assay to quantify candidate ovarian cancer protein biomarkers in sera. Among the 64 peptides corresponding to 23 proteins in our PRM assay, 24 peptides corresponding to 16 proteins passed the assay validation acceptability criteria. A total of 6 of these peptides from insulin-like growth factor-binding protein 2 (IBP2), sex hormone-binding globulin (SHBG), and TIMP metalloproteinase inhibitor 1 (TIMP1) were quantified in sera from a cohort of 69 patients with early-stage HGSOC, late-stage HGSOC, benign ovarian conditions, and healthy (non-cancer) controls. Confirming the results from previously published studies using orthogonal analytical approaches, IBP2 was identified as a diagnostic biomarker candidate based on its significantly increased abundance in the late-stage HGSOC patient sera compared to the healthy controls and patients with benign ovarian conditions.

CONCLUSIONS

A multiplexed targeted PRM MS assay was applied to detect candidate diagnostic biomarkers in HGSOC sera. To evaluate the clinical utility of the IBP2 PRM assay for HGSOC detection, further studies need to be performed using a larger patient cohort.

Metformin suppresses LRG1 and TGFβ1/ALK1-induced angiogenesis and protects against ultrastructural changes in rat diabetic nephropathy

Diabetic nephropathy (DN) has high prevalence and poor prognosis which make it a research priority for scientists. Since metformin, a hypoglycaemic drug, has been found to prolong the survival of mice with DN. This study aims at investigating the molecular mechanisms leading to DN in rats and to explore the role of leucine-rich α-2-glycoprotein-1 (LRG1), activin-like kinase1 (ALK1), and transforming growth factor-β (TGFβ1) in the pathologic alterations seen in DN. The aim was also extended to explore the protective action of metformin against DN in rats and its influence on LRG1and ALK1/TGFβ1 induced renal angiogenesis. 24 male rats were used. Rats were assigned as, the vehicle group, the diabetic control group and diabetic + metformin (100 and 200 mg/kg) groups. Kidney samples were processed for histopathology, immunohistochemistry and biochemical analysis. Bioinformatic analysis of studied proteins was done to determine protein-protein interactions. Metformin reduced serum urea and creatinine significantly, decreased the inflammatory cytokine levels and reduced LRG1, TGFβ1, ALK1 and vascular endothelial growth factor (VEGF) proteins in rat kidneys. Bioinformatic analysis revealed interactions between the studied proteins. Metformin alleviated the histopathological changes observed in the diabetic rats such as the glomerular surface area and increased Bowman's space diameter. Metformin groups showed decreased VEGF immunostaining compared to diabetic group. Metformin shows promising renoprotective effects in diabetic model that was at least partly mediated by downregulation of LRG1 and TGFβ1/ALK1-induced renal angiogenesis. These results further explain the molecular mechanism of metformin in DN management.

Multi-biomarker panel prediction model for diagnosis of pancreatic cancer

BACKGROUND/PURPOSE

The current study aimed to develop a prediction model using a multi-marker panel as a diagnostic screening tool for pancreatic ductal adenocarcinoma.

METHODS

Multi-center cohort of 1991 blood samples were collected from January 2011 to September 2019, of which 609 were normal, 145 were other cancer (colorectal, thyroid, and breast cancer), 314 were pancreatic benign disease, and 923 were pancreatic ductal adenocarcinoma. The automated multi-biomarker Enzyme-Linked Immunosorbent Assay kit was developed using three potential biomarkers: LRG1, TTR, and CA 19-9. Using a logistic regression model on a training data set, the predicted values for pancreatic ductal adenocarcinoma were obtained, and the result was classification into one of the three risk groups: low, intermediate, and high. The five covariates used to create the model were sex, age, and three biomarkers.

RESULTS

Participants were categorized into four groups as normal (n = 609), other cancer (n = 145), pancreatic benign disease (n = 314), and pancreatic ductal adenocarcinoma (n = 923). The normal, other cancer, and pancreatic benign disease groups were clubbed into the non-pancreatic ductal adenocarcinoma group (n = 1068). The positive and negative predictive value, sensitivity, and specificity were 94.12, 90.40, 93.81, and 90.86, respectively.

CONCLUSIONS

This study demonstrates a significant diagnostic performance of the multi-marker panel in distinguishing pancreatic ductal adenocarcinoma from normal and benign pancreatic disease states, as well as patients with other cancers.

Novel Diagnostic Biomarkers for High-Grade Serous Ovarian Cancer Uncovered by Data-Independent Acquisition Mass Spectrometry

High-grade serous ovarian cancer (HGSOC) represents the major histological type of ovarian cancer, and the lack of effective screening tools and early detection methods significantly contributes to the poor prognosis of HGSOC. Currently, there are no reliable diagnostic biomarkers for HGSOC. In this study, we performed liquid chromatography data-independent acquisition tandem mass spectrometry (MS) on depleted serum samples from 26 HGSOC cases and 24 healthy controls (HCs) to discover potential HGSOC diagnostic biomarkers. A total of 1,847 proteins were identified across all samples, among which 116 proteins showed differential expressions between HGSOC patients and HCs. Network modeling showed activations of coagulation and complement cascades, platelet activation and aggregation, neutrophil extracellular trap formation, toll-like receptor 4, insulin-like growth factor, and transforming growth factor β signaling, as well as suppression of lipoprotein assembly and Fc gamma receptor activation in HGSOC. Based on the network model, we prioritized 28 biomarker candidates and validated 18 of them using targeted MS assays in an independent cohort. Predictive modeling showed a sensitivity of 1 and a specificity of 0.91 in the validation cohort. Finally, in vitro functional assays on four potential biomarkers (FGA, VWF, ARHGDIB, and SERPINF2) suggested that they may play an important role in cancer cell proliferation and migration in HGSOC. All raw data were deposited in PRIDE (PXD033169).

LRG1 mediated by ATF3 promotes growth and angiogenesis of gastric cancer by regulating the SRC/STAT3/VEGFA pathway

BACKGROUND

Increasing evidence indicates that leucine-rich-alpha-2-glycoprotein 1 (LRG1) is associated with multiple malignancies, but whether it participates in gastric cancer (GC) angiogenesis remains unclear.

METHODS

The expression levels of LRG1 were assessed in GC samples. Endothelial tube formation analysis, HUVEC migration assay, chorioallantoic membrane assay (CAM), and xenograft tumor model were used to investigate the effect of LRG1 on angiogenesis in gastric cancer. The involvement of activating transcription factor 3 (ATF3) was analyzed by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assay. Western blot and enzyme-linked immunosorbent assay were performed to measure the SRC/STAT3/VEGFA pathway.

RESULTS

LRG1 was overexpressed in GC tissues and associated with cancer angiogenesis. In addition, LRG1 markedly promoted GC cell proliferation in vitro and in vivo. Moreover, overexpression of LRG1 could stimulate GC angiogenesis in vitro and in vivo. Then, we identified ATF3 promotes the transcription of LRG1 and is a positive regulator of angiogenesis. Additionally, LRG1 could activate VEGFA expression via the SRC/STAT3/ VEGFA pathway in GC cells, thus contributing to the angiogenesis of GC.

CONCLUSIONS

The present study suggests LRG1 plays a crucial role in the regulation of angiogenesis in GC and could be a potential therapeutic target for GC.

Diagnostic circulating biomarkers to detect vision-threatening diabetic retinopathy: Potential screening tool of the future?

With the increasing prevalence of diabetes in developing and developed countries, the socio-economic burden of diabetic retinopathy (DR), the leading complication of diabetes, is growing. Diabetic retinopathy (DR) is currently one of the leading causes of blindness in working-age adults worldwide. Robust methodologies exist to detect and monitor DR; however, these rely on specialist imaging techniques and qualified practitioners. This makes detecting and monitoring DR expensive and time-consuming, which is particularly problematic in developing countries where many patients will be remote and have little contact with specialist medical centres. Diabetic retinopathy (DR) is largely asymptomatic until late in the pathology. Therefore, early identification and stratification of vision-threatening DR (VTDR) is highly desirable and will ameliorate the global impact of this disease. A simple, reliable and more cost-effective test would greatly assist in decreasing the burden of DR around the world. Here, we evaluate and review data on circulating protein biomarkers, which have been verified in the context of DR. We also discuss the challenges and developments necessary to translate these promising data into clinically useful assays, to detect VTDR, and their potential integration into simple point-of-care testing devices.

Latrophilin-2 is a novel receptor of LRG1 that rescues vascular and neurological abnormalities and restores diabetic erectile function

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia, which causes endothelial dysfunction and peripheral neuropathy, ultimately leading to multiple complications. One prevalent complication is diabetic erectile dysfunction (ED), which is more severe and more resistant to treatment than nondiabetic ED. The serum glycoprotein leucine-rich ɑ-2-glycoprotein 1 (LRG1) is a modulator of TGF-β-mediated angiogenesis and has been proposed as a biomarker for a variety of diseases, including DM. Here, we found that the adhesion GPCR latrophilin-2 (LPHN2) is a TGF-β-independent receptor of LRG1. By interacting with LPHN2, LRG1 promotes both angiogenic and neurotrophic processes in mouse tissue explants under hyperglycemic conditions. Preclinical studies in a diabetic ED mouse model showed that LRG1 administration into the penile tissue, which exhibits significantly increased LPHN2 expression, fully restores erectile function by rescuing vascular and neurological abnormalities. Further investigations revealed that PI3K, AKT, and NF-κB p65 constitute the key intracellular signaling pathway of the LRG1/LPHN2 axis, providing important mechanistic insights into LRG1-mediated angiogenesis and nerve regeneration in DM. Our findings suggest that LRG1 can be a potential new therapeutic option for treating aberrant peripheral blood vessels and neuropathy associated with diabetic complications, such as diabetic ED.

LRG1 in pancreatic cancer cells promotes inflammatory factor synthesis and the angiogenesis of HUVECs by activating VEGFR signaling

BACKGROUND

This study aimed to investigate the roles of leucine-rich alpha-2-glycoprotein 1 (LRG1) in regulating angiogenesis during pancreatic cancer (PC) pathogenesis.

METHODS

LRG1 expression in tissues was detected by qRT-PCR and immunohistochemistry. LRG1 in BxPC-3 and Capan-2 cells was knocked down or overexpressed. Cell viability and the migration and invasion abilities of cells were analyzed using the Cell Counting Kit-8 (CCK-8) assay and Transwell system, respectively. Interleukin-1 beta (IL-1β), IL-18, and vascular endothelial growth factor A (VEGFA) contents in cell culture were measured by ELISA, and the angiogenesis of HUVECs was assessed by the in vitro tube formation assay. In vitro LRG1 expression in BxPC-3 and Capan-2 cells was determined using immunofluorescence.

RESULTS

The results showed that LRG1 expression was significantly increased in pancreatic cancer tissues and cell lines. LRG1 knockdown inhibited the viability, migration, invasion, and IL-1β and IL-18 synthesis of BxPC-3 and Capan-2 cells. VEGFA synthesis in BxPC-3 and Capan-2 cells was also inhibited by LRG1 knockdown, which caused impaired tube formation of co-cultured HUVECs. LRG1 overexpression enhanced the viability, migration, and invasion of BxPC-3 and Capan-2 cells, also causing elevated tube formation of HUVECs and IL-1β and IL-18 synthesis in co-cultures of HUVECs and BxPC-3 or Capan-2 cells. Silencing of VEGF receptor (VEGFR) abrogated the enhanced tube formation and IL-1β and IL-18 synthesis in HUVECs co-cultured with BxPC-3 or Capan-2 cells overexpressing LRG1.

CONCLUSIONS

In conclusion, LRG1, which is highly expressed in pancreatic cancer cells, promotes inflammatory factor synthesis and the angiogenesis of HUVECs though activating the VEGFR signaling pathway.

LRG1: an emerging player in disease pathogenesis

The secreted glycoprotein leucine-rich α-2 glycoprotein 1 (LRG1) was first described as a key player in pathogenic ocular neovascularization almost a decade ago. Since then, an increasing number of publications have reported the involvement of LRG1 in multiple human conditions including cancer, diabetes, cardiovascular disease, neurological disease, and inflammatory disorders. The purpose of this review is to provide, for the first time, a comprehensive overview of the LRG1 literature considering its role in health and disease. Although LRG1 is constitutively expressed by hepatocytes and neutrophils, Lrg1-/- mice show no overt phenotypic abnormality suggesting that LRG1 is essentially redundant in development and homeostasis. However, emerging data are challenging this view by suggesting a novel role for LRG1 in innate immunity and preservation of tissue integrity. While our understanding of beneficial LRG1 functions in physiology remains limited, a consistent body of evidence shows that, in response to various inflammatory stimuli, LRG1 expression is induced and directly contributes to disease pathogenesis. Its potential role as a biomarker for the diagnosis, prognosis and monitoring of multiple conditions is widely discussed while dissecting the mechanisms underlying LRG1 pathogenic functions. Emphasis is given to the role that LRG1 plays as a vasculopathic factor where it disrupts the cellular interactions normally required for the formation and maintenance of mature vessels, thereby indirectly contributing to the establishment of a highly hypoxic and immunosuppressive microenvironment. In addition, LRG1 has also been reported to affect other cell types (including epithelial, immune, mesenchymal and cancer cells) mostly by modulating the TGFβ signalling pathway in a context-dependent manner. Crucially, animal studies have shown that LRG1 inhibition, through gene deletion or a function-blocking antibody, is sufficient to attenuate disease progression. In view of this, and taking into consideration its role as an upstream modifier of TGFβ signalling, LRG1 is suggested as a potentially important therapeutic target. While further investigations are needed to fill gaps in our current understanding of LRG1 function, the studies reviewed here confirm LRG1 as a pleiotropic and pathogenic signalling molecule providing a strong rationale for its use in the clinic as a biomarker and therapeutic target.

The role of leucine-rich alpha-2-glycoprotein-1 in proliferation, migration, and invasion of tumors

BACKGROUND

Leucine-rich alpha-2-glycoprotein-1 (LRG1) is widely involved in proliferation, migration, and invasion of various tumor cells. Recent studies have evaluated the potential of LRG1 as both an early tumor and a prognostic biomarker.

METHOD

The relevant literature from PubMed is reviewed in this article.

RESULTS

It has been found that LRG1 mainly acts on the regulatory mechanisms of angiogenesis, epithelial-mesenchymal transition (EMT), and apoptosis by transforming growth factor (TGF-β) signaling pathway as well as affecting the occurrence and development of the tumors. Moreover, with advancement of research, LRG1 regulation pathways which are independent of TGF-β signaling pathway have been gradually revealed in different tumor cells; There are several studies on the biological effects of LRG1 as an inflammatory factor, vascular growth regulator, cell adhesion, and a cell viability influencing factor. In addition, various tumor suppression methods which are based on regulation of LRG1 levels have also shown high potential clinical value.

CONCLUSIONS

LRG1 are critical for the processes of tumorigenesis, development, and metastasis in various tumors. The present study reviewed the latest research on the achievements of LRG1 in tumor genesis and development. Further, this study also discussed the related molecular mechanisms of various biological functions of LRG1.

Colorectal cancer-associated fibroblasts promote metastasis by up-regulating LRG1 through stromal IL-6/STAT3 signaling

Cancer-associated fibroblasts (CAFs) have been shown to play a strong role in colorectal cancer metastasis, yet the underlying mechanism remains to be fully elucidated. Using CRC clinical samples together with ex vivo CAFs-CRC co-culture models, we found that CAFs induce expression of Leucine Rich Alpha-2-Glycoprotein 1(LRG1) in CRC, where it shows markedly higher expression in metastatic CRC tissues compared to primary tumors. We further show that CAFs-induced LRG1 promotes CRC migration and invasion that is concomitant with EMT (epithelial-mesenchymal transition) induction. In addition, this signaling axis has also been confirmed in the liver metastatic mouse model which displayed CAFs-induced LRG1 substantially accelerates metastasis. Mechanistically, we demonstrate that CAFs-secreted IL-6 (interleukin-6) is responsible for LRG1 up-regulation in CRC, which occurs through a direct transactivation by STAT3 following JAK2 activation. In clinical CRC tumor samples, LRG1 expression was positively correlated with CAFs-specific marker, α-SMA, and a higher LRG1 expression predicted poor clinical outcomes especially distant metastasis free survival, supporting the role of LRG1 in CRC progression. Collectively, this study provided a novel insight into CAFs-mediated metastasis in CRC and indicated that therapeutic targeting of CAFs-mediated IL-6-STAT3-LRG1 axis might be a potential strategy to mitigate metastasis in CRC.

Review of early circulating biomolecules associated with diabetes nephropathy - Ideal candidates for early biomarker array test for DN

BACKGROUND

Diabetic nephropathy (DN) is one of the catastrophic complications of type 2 diabetes mellitus (T2DM). 45% of DN patients progressed to End Stage Renal Disease (ESRD) which robs casualties of the quality of live. The challenge in early diagnosis of DN is it is asymptomatic in the early phase. Current gold standard test for screening and diagnosis of DN are nonspecific and are not sensitive in detecting DN early enough and subsequently monitor renal function during management and intervention plans. Recent studies reported various biomolecules which are associated with the onset of DN in T2DM using cutting-edge technologies. These biomolecules could be potential early biomarkers for DN. This review selectively identified potential early serum biomolecules which are potential candidates for developing an Early Biomarker Array Test for DN.

METHODS

An advanced literature search was conducted on 4 online databases. Search terms used were "Diabetes Mellitus, Type 2", "Diabetic nephropathy", "pathogenesis" and "early biomarker. Filters were applied to capture articles published from 2010 to 2020, written in English, human or animal models and focused on serum biomolecules associated with DN.

RESULTS

Five serum biomolecules have been evidently described as contributing pivotal roles in the pathophysiology of DN. MiR-377, miR-99b, CYP2E1, TGF-β1 and periostin are potential candidates for designing an early biomarker array for screening and diagnosis of early stages of DN. The five shortlisted biomolecules originates from endogenous biochemical processes which are specific to the progressive pathophysiology of DN.

CONCLUSION

miR-377, miR-99b, CYP2E1, TGF-β1 and periostin are potential candidate biomolecules for diagnosing DN at the early phases and can be developed into a panel of endogenous biomarkers for early detection of DN in patients with T2DM. The outcomes of this study will be a stepping stone towards planning and developing an early biomarker array test for diabetic nephropathy. The proposed panel of early biomarkers for DN has potential of stratifying the stages of DN because each biomolecule appears at distinct stages in the pathophysiology of DN.

LRG1 destabilizes tumor vessels and restricts immunotherapeutic potency

BACKGROUND

A poorly functioning tumor vasculature is pro-oncogenic and may impede the delivery of therapeutics. Normalizing the vasculature, therefore, may be beneficial. We previously reported that the secreted glycoprotein leucine-rich α-2-glycoprotein 1 (LRG1) contributes to pathogenic neovascularization. Here, we investigate whether LRG1 in tumors is vasculopathic and whether its inhibition has therapeutic utility.

METHODS

Tumor growth and vascular structure were analyzed in subcutaneous and genetically engineered mouse models in wild-type and Lrg1 knockout mice. The effects of LRG1 antibody blockade as monotherapy, or in combination with co-therapies, on vascular function, tumor growth, and infiltrated lymphocytes were investigated.

FINDINGS

In mouse models of cancer, Lrg1 expression was induced in tumor endothelial cells, consistent with an increase in protein expression in human cancers. The expression of LRG1 affected tumor progression as Lrg1 gene deletion, or treatment with a LRG1 function-blocking antibody, inhibited tumor growth and improved survival. Inhibition of LRG1 increased endothelial cell pericyte coverage and improved vascular function, resulting in enhanced efficacy of cisplatin chemotherapy, adoptive T cell therapy, and immune checkpoint inhibition (anti-PD1) therapy. With immunotherapy, LRG1 inhibition led to a significant shift in the tumor microenvironment from being predominantly immune silent to immune active.

CONCLUSIONS

LRG1 drives vascular abnormalization, and its inhibition represents a novel and effective means of improving the efficacy of cancer therapeutics.

FUNDING

Wellcome Trust (206413/B/17/Z), UKRI/MRC (G1000466, MR/N006410/1, MC/PC/14118, and MR/L008742/1), BHF (PG/16/50/32182), Health and Care Research Wales (CA05), CRUK (C42412/A24416 and A17196), ERC (ColonCan 311301 and AngioMature 787181), and DFG (CRC1366).

Detection of leucine-rich alpha-2-glycoprotein 1-containing immunocomplexes in the plasma of lung cancer patients with epitope-specific mAbs

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide. With the expectation of improved survival, tremendous efforts and resources have been invested in the discovery of specific biomarkers for early detection of the disease. Several investigators have reported the presence of cancer-associated autoantibodies in the plasma or serum of lung cancer patients. Previously, we used a monoclonal-antibody proteomics technology platform for the discovery of novel lung cancer-associated proteins.

OBJECTIVE

The identification of specific protein epitopes associated with various cancers is a promising method in biomarker discovery. Here, in a preliminary study, we aimed to detect autoantibody-leucine-rich alpha-2-glycoprotein 1 (LRG1) immunocomplexes using epitope-specific monoclonal antibodies (mAbs).

METHODS

We performed sandwich ELISA assays using the LRG1 epitope-specific capture mAbs, Bsi0352 and Bsi0392, and an IgG-specific polyclonal antibody coupled to a reporter system as the detection reagent. We tested the plasma of lung-cancer patients and apparently healthy controls.

RESULTS

Depending on the epitope specificity of the capture monoclonal mAb, we were either unable to distinguish the control from LC-groups or showed a higher level of LRG1 and IgG autoantibody containing immunocomplexes in the plasma of non-small cell lung cancer and small cell lung cancer subgroups of lung cancer patients than in the plasma of control subjects.

CONCLUSIONS

Our findings underline the importance of protein epitope-specific antibody targeted approaches in biomarker research, as this may increase the accuracy of previously described tests, which will need further validation in large clinical cohorts.

Paradoxical Roles of Leucine-Rich α2-Glycoprotein-1 in Cell Death and Survival Modulated by Transforming Growth Factor-Beta 1 and Cytochrome c

Leucine-rich α₂-glycoprotein-1 (LRG1) has been shown to impact both apoptosis and cell survival, pleiotropic effects similar to one of its known ligands, transforming growth factor-beta 1 (TGF-β1). Recent studies have given insight into the TGF-β1 signaling pathways involved in LRG1-mediated death versus survival signaling, i.e., canonical or non-canonical. Interaction of LRG1 with another ligand, extracellular cytochrome c (Cyt c), promotes cell survival, at least for lymphocytes. LRG1 has been shown to bind Cyt c with high affinity, higher than it binds TGF-β1, making it sensitive to small changes in the level of extracellular Cyt c within a microenvironment that may arise from cell death. Evidence is presented here that LRG1 can bind TGF-β1 and Cyt c simultaneously, raising the possibility that the ternary complex may present a signaling module with the net effect of signaling, cell death versus survival, determined by the relative extent to which the LRG1 binding sites are occupied by these two ligands. A possible role for LRG1 should be considered in studies where extracellular effects of TGF-β1 and Cyt c have been observed in media supplemented with LRG1-containing serum.

LRG1 promotes hypoxia-induced cardiomyocyte apoptosis and autophagy by regulating hypoxia-inducible factor-1α

Cardiomyocyte apoptosis and autophagy play important roles in acute myocardial infarction (AMI), but the effect of leucine-rich alpha-2-glycoprotein 1 (LRG1) on the apoptosis and autophagy of H9c2 has not yet been reported. It was found through differential gene analysis and LASSO analysis that LRG1 was the key gene in AMI. In this study, western blot was applied to detect the protein expression of Bax, Bcl2, LC3, p62, LRG1 and hypoxia-inducible factor-1α (HIF-1α); CCK-8 assay was employed to detect cell viability; Annexin V-FITC/PI staining was adopted to evaluate apoptosis, and immunofluorescence assay was applied to detect autophagy. Under hypoxia conditions in H9c2 cells, LRG1 protein levels were increased, the cell activity was decreased, and apoptosis and autophagy were promoted; the downregulated LRG1 significantly enhanced cell viability but inhibited apoptosis and autophagy. When knocking down HIF-1α in the overexpressed LRG1 cells, the effects of LRG1 were reversed under hypoxia condition. In conclusion, LRG1/HIF-1α promoted H9c2 cell apoptosis and autophagy in hypoxia, potentially providing new ideas for the determination and treatment of AMI.

Abbreviation: LRG1: Leucine-rich alpha-2-glycoprotein 1; LRR: leucine-rich repeat; HIF-1α: Hypoxia-inducible factor-1α; AMI: acute myocardial infarction

Temporal multi-omics identifies LRG1 as a vascular niche instructor of metastasis

Metastasis is the primary cause of cancer-related mortality. Tumor cell interactions with cells of the vessel wall are decisive and potentially rate-limiting for metastasis. The molecular nature of this cross-talk is, beyond candidate gene approaches, hitherto poorly understood. Using endothelial cell (EC) bulk and single-cell transcriptomics in combination with serum proteomics, we traced the evolution of the metastatic vascular niche in surgical models of lung metastasis. Temporal multiomics revealed that primary tumors systemically reprogram the body’s vascular endothelium to perturb homeostasis and to precondition the vascular niche for metastatic growth. The vasculature with its enormous surface thereby serves as amplifier of tumor-induced instructive signals. Comparative analysis of lung EC gene expression and secretome identified the transforming growth factor–β (TGFβ) pathway specifier LRG1, leucine-rich alpha-2-glycoprotein 1, as an early instructor of metastasis. In the presence of a primary tumor, ECs systemically up-regulated LRG1 in a signal transducer and activator of transcription 3 (STAT3)–dependent manner. A meta-analysis of retrospective clinical studies revealed a corresponding up-regulation of LRG1 concentrations in the serum of patients with cancer. Functionally, systemic up-regulation of LRG1 promoted metastasis in mice by increasing the number of prometastatic neural/glial antigen 2 (NG2)+ perivascular cells. In turn, genetic deletion of Lrg1 hampered growth of lung metastasis. Postsurgical adjuvant administration of an LRG1-neutralizing antibody delayed metastatic growth and increased overall survival. This study has established a systems map of early primary tumor-induced vascular changes and identified LRG1 as a therapeutic target for metastasis.

Reversal of emphysema by restoration of pulmonary endothelial cells

Chronic obstructive pulmonary disease (COPD) is marked by airway inflammation and airspace enlargement (emphysema) leading to airflow obstruction and eventual respiratory failure. Microvasculature dysfunction is associated with COPD/emphysema. However, it is not known if abnormal endothelium drives COPD/emphysema pathology and/or if correcting endothelial dysfunction has therapeutic potential. Here, we show the centrality of endothelial cells to the pathogenesis of COPD/emphysema in human tissue and using an elastase-induced murine model of emphysema. Airspace disease showed significant endothelial cell loss, and transcriptional profiling suggested an apoptotic, angiogenic, and inflammatory state. This alveolar destruction was rescued by intravenous delivery of healthy lung endothelial cells. Leucine-rich α-2-glycoprotein-1 (LRG1) was a driver of emphysema, and deletion of Lrg1 from endothelial cells rescued vascular rarefaction and alveolar regression. Hence, targeting endothelial cell biology through regenerative methods and/or inhibition of the LRG1 pathway may represent strategies of immense potential for the treatment of COPD/emphysema.

The Prognostic Value of Leucine-Rich α2 Glycoprotein 1 in Pediatric Spinal Cord Injury

Objective

Leucine-rich α2 glycoprotein 1 (LRG1) is a novel cytokine, which is believed to be involved in the inflammatory process of a series of diseases. However, the relationship between LRG1 and spinal cord injury (SCI) has not been reported. The purpose of our study is to determine the predictive value of LRG1 for the prognosis of pediatric SCI (PSCI).

Methods

This study recruited 64 patients with confirmed PSCI and 40 healthy controls at Foshan Traditional Chinese Medicine Hospital from January 2016 to December 2020. The clinical information of all participants at the time of admission was recorded. Peripheral blood was collected, and commercial reagents were used to detect the level of serum LRG1. At the same time, the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) was used to assess the severity of PSCI.

Results

All participants were divided into PSCI group (n = 64) and NC group (n = 40). There was no significant difference in clinical information (age, gender, heart rate, systolic blood pressure, diastolic blood pressure, sampling time from injury, white blood cells, and C-reactive protein) between the two groups (p > 0.05). According to the interquartile range of serum LRG1, we compared the motor and sensory scores of ISNCSCI and found that serum LRG1 levels were negatively correlated with the prognosis of PSCI patients (p < 0.001). The results of receiver operating curve (ROC) showed that the sensitivity, specificity, and AUC (Area Under the Curve) of serum LRG1 level in predicting the prognosis of PSCI were 68.4%, 69.1%, and 0.705, respectively. The cut-off value of serum LRG1 level predicting the prognosis of PSCI is 21.1 μg/ml.

Conclusions

Serum LRG1 level is significantly increased in PSCI patients, and the elevated LRG1 level is negatively correlated with the prognosis of PSCI patients. Serum LRG1 may be a potentially useful biomarker for predicting PSCI.

Leucine-Rich α-2-Glycoprotein 1 Suppresses Endothelial Cell Activation Through ADAM10-Mediated Shedding of TNF-α Receptor

Elevated serum concentrations of leucine-rich α-2-glycoprotein (LRG1) have been reported in patients with inflammatory, autoimmune, and cardiovascular diseases. This study aims to investigate the role of LRG1 in endothelial activation. LRG1 in endothelial cells (ECs) of arteries and serum of patients with critical limb ischemia (CLI) was assessed by immunohistochemistry and ELISA, respectively. LRG1 expression in sheared and tumor necrosis factor-α (TNF-α)-treated ECs was analyzed. The mechanistic role of LRG1 in endothelial activation was studied in vitro. Plasma of 37-week-old Lrg1 ^-/- mice was used to investigate causality between LRG1 and tumor necrosis factor receptor 1 (TNFR1) shedding. LRG1 was highly expressed in ECs of stenotic but not normal arteries. LRG1 concentrations in serum of patients with CLI were elevated compared to healthy controls. LRG1 expression was shear dependent. It could be induced by TNF-α, and the induction of its expression was mediated by NF-κB activation. LRG1 inhibited TNF-α-induced activation of NF-κB signaling, expression of VCAM-1 and ICAM-1, and monocyte capture, firm adhesion, and transendothelial migration. Mechanistically, LRG1 exerted its function by causing the shedding of TNFR1 via the ALK5-SMAD2 pathway and the subsequent activation of ADAM10. Consistent with this mechanism, LRG1 and sTNFR1 concentrations were correlated in the serum of CLI patients. Causality between LRG1 and TNFR1 shedding was established by showing that Lrg1 ^-/- mice had lower plasma sTNFR1 concentrations than wild type mice. Our results demonstrate a novel role for LRG1 in endothelial activation and its potential therapeutic role in inflammatory diseases should be investigated further.

Serum and Urine Biomarker Leucine-Rich Alpha-2 Glycoprotein 1 Differentiates Pediatric Acute Complicated and Uncomplicated Appendicitis

PURPOSE

This prospective, single-center cohort study analyzes the potential of inflammatory protein mediator leucine-rich alpha-2 glycoprotein 1 (LRG1) for the early and accurate diagnosis of acute appendicitis (AA), and differentiation of acute complicated (AcA) from uncomplicated appendicitis (AuA).

METHODS

Participants were divided into the AcA, AuA, and control groups, and their serum (s-LRG1) and urine LRG1 (u-LRG1) levels were assayed preoperatively on the second and fifth postoperative days.

RESULTS

153 patients participated, 97 had AA. Preoperative u-LRG1 with a cut-off value of 0.18 μg/mL generated an area under the receiver operated characteristic (AUC) curve of 0.70 (95% CI 0.62-0.79) for AA versus control (p < 0.001), while the results for AcA versus AuA were not significant (AUC 0.60, 95% CI 0.49-0.71, p = 0.089). The s-LRG1 levels of AA versus the control with a cut-off value of 51.69 μg/mL generated an AUC of 0.94 (95% CI 0.91-0.99, p < 0.001). The cut-off value of s-LRG1 was 84.06 μg/mL for diagnosis of AcA from AuA, and therefore, significant (AUC 0.69, 95% CI 0.59-0.80, p = 0.001).

CONCLUSIONS

LRG1 exhibited excellent diagnostic performance as an inexpensive, non-invasive, rapid, and accurate biomarker able to reflect the pathogenesis of AA. LRG1 has the potential to replace advanced imaging to diagnose clinically ambiguous AA cases.

LRG1 Mitigates Renal Interstitial Fibrosis through Alleviating Capillary Rarefaction and Inhibiting Inflammatory and Pro-Fibrotic Cytokines

INTRODUCTION

Increasing evidence has demonstrated that loss of peritubular capillaries plays a critical role in renal interstitial fibrosis. Leucine-rich α2-glycoprotein-1 (LRG1) has been observed promoting angiogenesis in the ocular disease mouse model and myocardial infarction model. We aimed to explore the role of LRG1 in renal interstitial fibrosis.

METHODS

We analyzed the expression of LRG1 in the plasma and kidney of CKD patients by ELISA and immunohistochemistry. Relationships between the expression of LRG1 in plasma and kidney and renal fibrosis and inflammation were analyzed. Tube formation assay was used to detect the angiogenesis in the human umbilical vein endothelial cell lines (HUVECs). And real-time PCR was used to detect the mRNA expression of LRG1, inflammatory factors, renal tubular injury indicators, pro-fibrotic cytokines, and CD31. We examined the effects of genetic ablation of LRG1 on renal fibrosis induced by unilateral ureteral obstruction (UUO) mice model at day 7.

RESULTS

We demonstrated that the expression of LRG1 in renal tissues and plasma samples was upregulated in CKD patients. And the expression of LRG1 was elevated in human renal tubular epithelial cell line (HK-2) cells in response to the stimulation of TNF-α in vitro, and in kidney after UUO in vivo. The deficiency of the LRG1 gene aggravated renal fibrosis, inflammatory cells infiltration, and capillary rarefaction after UUO. In vitro, LRG1 promoted the tube formation of HUVEC cells. LRG1 inhibits fibronectin secretion induced by TGF-β1 in HK-2 and overexpression of LRG1 in HK-2 cells decreased fibronectin secretion.

CONCLUSION

LRG1 may prevent renal fibrosis by inhibiting the secretion of inflammatory and pro-fibrotic cytokines and promoting angiogenesis.

The Multipotential of Leucine-Rich α-2 Glycoprotein 1 as a Clinicopathological Biomarker of Glioblastoma

Leucine-rich α-2 glycoprotein 1 (LRG1) is a diagnostic marker candidate for glioblastoma. Although LRG1 has been associated with angiogenesis, it has been suggested that its biomarker role differs depending on the type of tumor. In this study, a clinicopathological examination of LRG1's role as a biomarker for glioblastoma was performed. We used tumor tissues of 155 cases with diffuse gliomas (27 astrocytomas, 14 oligodendrogliomas, 114 glioblastomas). The immunohistochemical LRG1 intensity scoring was classified into 2 groups: low expression and high expression. Mutations of IDH1, IDH2, and TERT promoter were analyzed through the Sanger method. We examined the relationship between LRG1 expression level in glioblastoma and clinical parameters, such as age, preoperative Karnofsky performance status, tumor location, extent of resection, O6-methylguanine DNA methyltransferase promoter, and prognosis. LRG1 high expression rate was 41.2% in glioblastoma, 3.7% in astrocytoma, and 21.4% in oligodendroglioma. Glioblastoma showed a significantly higher LRG1 expression than lower-grade glioma (p = 0.0003). High expression of LRG1 was an independent favorable prognostic factor (p = 0.019) in IDH-wildtype glioblastoma and correlated with gross total resection (p = 0.002) and the tumor location on nonsubventricular zone (p = 0.00007). LRG1 demonstrated multiple potential as a diagnostic, prognostic, and regional biomarker for glioblastoma.

Knockdown of lncRNA NEAT1 expression inhibits cell migration, invasion and EMT by regulating the miR-24-3p/LRG1 axis in retinoblastoma cells

Retinoblastoma (RB) is the most common primary intraocular cancer type that occurs during retinal development in childhood. Previous studies have reported that long non-coding RNAs (lncRNAs) are involved in the development of RB. Therefore, the aim of the present study was to investigate the effects and underlying regulatory mechanisms of nuclear paraspeckle assembly transcript 1 (NEAT1) in RB. The expression levels of NEAT1, microRNA (miR)-24-3p and leucine-rich-α-2-glycoprotein (LRG1) were detected using reverse transcription-quantitative PCR (RT-qPCR). Moreover, the protein expression levels of LRG1, matrix metalloproteinase 9, N-cadherin and E-cadherin were detected via western blotting. Furthermore, cell migration and invasion abilities were evaluated via Transwell assays. The targeting relationships between miR-24-3p and NEAT1 or LRG1 were predicted using online software and confirmed via dual-luciferase reporter assay. In the present study, NEAT1 and LRG1 were upregulated, and miR-24-3p was downregulated in RB tissues and cells compared with the corresponding healthy tissues and cells. Moreover, miR-24-3p was identified as a target of NEAT and LRG1 was demonstrated to be a direct target gene of miR-24-3p. Knockdown of NEAT1 or LRG1 significantly suppressed RB cell migration and invasion ability, while the effects were reversed by an miR-24-3p inhibitor. In addition, the downregulation of LRG1 caused by miR-24-3p was restored following the overexpression of NEAT1 in RB cells. It was also demonstrated that NEAT1 knockdown inhibited the epithelial-to-mesenchymal transition (EMT) pathway by inhibiting the expression of LRG via targeting miR-24-3p. In conclusion, the present results suggest that silencing of NEAT1 suppresses cell migration, invasion and the EMT process by downregulating LRG1 expression via sponging miR-24-3p in RB, thus indicating that NEAT1 may be a potential candidate for RB treatment.

Diagnostic performances of leucine-rich α-2-glycoprotein 1 and stem cell factor for diagnosis and follow-up of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most frequently diagnosed tumors worldwide with high mortality and morbidity. There is an urgent need for biomarkers to improve the outcomes and early detection of CRC. The sensitivity of traditional CRC tumor markers (carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9)) is not ideal. The levels of leucine-rich-alpha-2-glycoprotein 1 (LRG1) and stem cell factor (SCF) were evaluated, but the combined value of both markers is unclear. This case-control study included four groups: CRC patients before treatments (n = 22), CRC patients after treatments (n = 26), 20 patients with benign tumor, and 20 healthy subjects. Levels of routine biochemical and hematological markers, traditional tumor markers (CA19.9 and CEA), and candidate markers (LRG1 and SCF) were determined. Univariate and multivariate logistic regression analysis and area receiver-operating characteristic analysis (ROC) were used for evaluation the diagnostic performances of single and combined markers.

RESULTS

No significance difference in traditional tumor markers CEA, CA 19.9, and neutrophil-lymphocyte ratio (NLR) were found among study groups. SCF, LRG1, and platelet-lymphocyte ratio (PLR) were significantly decreased (p < 0.05) in non-treated CRC patients than after treated CRC. The combination between SCF and LRG1 showed highly significant difference in CRC patients compared with benign, healthy subjects, and among CRC groups (treated and non-treated) (p < 0.0001). The highest areas under curve (AUCs) were observed when LRG1 was used as a single predictor for discriminating CRC from healthy (0.87), benign (0.84), and non-treated CRC vs treated CRC (0.82). AUCs were jumped to 0.90, 0.84, and 0.84 when LRG1 and SCF were combined.

CONCLUSION

Our study revealed that LRG1 and SCF were potential diagnostic and follow-up markers for CRC.

Evaluation of the potential of Pap test fluid and cervical swabs to serve as clinical diagnostic biospecimens for the detection of ovarian cancer by mass spectrometry-based proteomics

BACKGROUND

The purpose of this study was to determine whether the residual fixative from a liquid-based Pap test or a swab of the cervix contained proteins that were also found in the primary tumor of a woman with high grade serous ovarian cancer. This study is the first step in determining the feasibility of using the liquid-based Pap test or a cervical swab for the detection of ovarian cancer protein biomarkers.

METHODS

Proteins were concentrated by acetone precipitation from the cell-free supernatant of the liquid-based Pap test fixative or eluted from the cervical swab. Protein was also extracted from the patient's tumor tissue. The protein samples were digested into peptides with trypsin, then the peptides were run on 2D-liquid chromatography mass spectrometry (2D-LCMS). The data was searched against a human protein database for the identification of peptides and proteins in each biospecimen. The proteins that were identified were classified for cellular localization and molecular function by bioinformatics integration.

RESULTS

We identified almost 5000 proteins total in the three matched biospecimens. More than 2000 proteins were expressed in each of the three biospecimens, including several known ovarian cancer biomarkers such as CA125, HE4, and mesothelin. By Scaffold analysis of the protein Gene Ontology categories and functional analysis using PANTHER, the proteins were classified by cellular localization and molecular function, demonstrating that the Pap test fluid and cervical swab proteins are similar to each other, and also to the tumor extract.

CONCLUSIONS

Our results suggest that Pap test fixatives and cervical swabs are a rich source of tumor-specific biomarkers for ovarian cancer, which could be developed as a test for ovarian cancer detection.

Cytomegalovirus and systemic inflammation at time of surgery is associated with worse outcomes in serous ovarian cancer

OBJECTIVES

Cytomegalovirus (CMV) is a common infection that establishes latency in healthy people. CMV has been associated with alterations of the immune compartment leading to improved responses, while inflammation has been shown to adversely impact outcomes. We investigated whether CMV serostatus predicts outcomes in ovarian cancer in the presence or absence of inflammation.

METHODS

A total of 106 patients with serous ovarian cancer from 2006 to 2009 were analyzed. CMV and systemic inflammation was measured using CMV immunoglobulin G (IgG) and C-reactive protein (CRP), respectively, in serum collected prior to cytoreduction. Patients were stratified by CMV IgG (non-reactive, reactive/borderline) and CRP (≤10, >10 mg/L) status. Overall survival (OS) and recurrence-free survival (RFS) were compared by group using log-rank tests and Cox proportional hazards regression models adjusting for age at surgery.

RESULTS

Of 106 eligible patients, 40 (37.7%) were CMV+/CRP+, 24 (22.6%) CMV+/CRP-, 19 (17.9%) CMV-/CRP+, and 23 (21.7%) CMV-/CRP-. CRP+ had higher CA-125 levels (P = 0.05) and higher rates of suboptimal debulking (P = 0.03). There were no other significant differences in demographic, surgical, or pathologic factors between groups. CMV+/CRP+ patients median RFS and OS were 16.9 months (95% CI: 9.0-21.1) and 31.7 months (95% CI: 25.0-48.7), respectively, with a significantly worse RFS (aHR: 1.85, 95% CI: 1.05-3.24, P = 0.03) and OS (aHR: 2.12, 95% CI: 1.17-3.82, P = 0.01) compared to CMV-/CRP- (RFS = 31.2 months (95% CI: 16.0-56.4) and OS = 63.8 months (95% CI: 50.7-87.0)). CMV+/CRP- group displayed the longest OS (89.3 months).

CONCLUSIONS

Previous exposure to CMV and high CRP at surgery portended worse RFS and OS compared to women who tested negative. The CMV+/CRP- group had the longest OS, indicating that CMV status alone, in the absence of inflammation, may be protective.

Identification and Validation of Leucine-rich α-2-glycoprotein 1 as a Noninvasive Biomarker for Improved Precision in Prostate Cancer Risk Stratification

Background

More accurate risk assessments are needed to improve prostate cancer management.

Objective

To identify blood-based protein biomarkers that provided prognostic information for risk stratification.

Design, setting, and participants

Mass spectrometry was used to identify biomarker candidates from blood, and validation studies were performed in four independent cohorts retrospectively collected between 1988 and 2015.

Outcome measurements and statistical analysis

The primary outcome objectives were progression-free survival, prostate cancer–specific survival (PCSS), and overall survival. Statistical analyses to assess survival and model performance were performed.

Results and limitation

Serum leucine-rich α-2-glycoprotein 1 (LRG1) was found to be elevated in fatal prostate cancer. LRG1 provided prognostic information independent of metastasis and increased the accuracy in predicting PCSS, particularly in the first 3 yr. A high LRG1 level is associated with an average of two-fold higher risk of disease-progression and mortality in both high-risk and metastatic patients. However, our study design, with a retrospective analysis of samples spanning several decades back, limits the assessment of the clinical utility of LRG1 in today’s clinical practice. Thus, independent prospective studies are needed to establish LRG1 as a clinically useful biomarker for patient management.

Conclusions

High blood levels of LRG1 are unfavourable in newly diagnosed high-risk and metastatic prostate cancer, and LRG1 increased the accuracy of risk stratification of prostate cancer patients.

Patient summary

High blood levels of leucine-rich α-2-glycoprotein 1 are unfavourable in newly diagnosed high-risk and metastatic prostate cancer.

The Clinical Prognostic Value of LRG1 in Esophageal Squamous Cell Carcinoma

BACKGROUND

Leucine-rich-alpha-2-glycoprotein1 (LRG1) is a new oncogene-related gene, which has been proven important for the development and poor prognosis of human cancers. However, whether it participates in esophageal squamous cell carcinoma (ESCC) progression remains unclear.

OBJECTIVE

To investigate the expression level and functional influence of LRG1 in ESCC.

METHODS

The expression of LRG1 was evaluated on the mRNA and protein level in ESCC patients. Then, correlation of LRG1 expression with clinicpathological variables was analyzed in ESCC. Besides, to clarify the biological function of LRG1, Eca109 and KYSE150 cells were transfected with LRG1 shRNA, the cell viability, clonal efficiency, apoptosis and invasion assays in vitro were performed.

RESULTS

LRG1 was significantly over-expressed in ESCC and related to deeper invasion depth (T stage) and distal metastasis (M stage). Kaplan-Meier analysis indicated that LRG1 up-regulation in ESCC was closely correlated to worse clinical survival (overall survival and progression-free survival), all P<0.001. LRG1 was confirmed to be an independent poor premonitory indicator for clinical outcomes in ESCC through the univariate and multivariate analyses. Down-regulation of LRG1 in ESCC cells markedly suppressed cell proliferation and invasion, stimulated apoptosis (all p <0.01).

CONCLUSION

LRG1 might play a significant role in the progression of ESCC, and could be served as a promising prognostic prediction for ESCC patients.

Expression of ADR-α1, 2 and ADR-β2 in cumulus cell culture of infertile women with polycystic ovary syndrome and poor responder who are a candidate for IVF: the novel strategic role of clonidine in this expression

OBJECTIVE

Alpha and beta-adrenoceptors (ADR-α1, 2, and β2) play a regulatory role in the folliculogenesis and steroidogenesis in the ovarian follicles. This study aimed to measure these adrenoceptors mRNA and its protein levels in cumulus cells (CCs) culture of poor ovarian reserve (POR) and polycystic ovarian syndrome (PCOS) infertile women (IVF candidate) and the effect of clonidine treatment at CCs culture.

METHODS

This case/control study was conducted in 2017 includes a control (donation oocytes) and two studies (PCO and POR) groups. The ovulation induction drugs were prescribed in all groups. After the oocyte puncture, the follicular fluid was collected and CCs were isolated were cultured. RNA was extracted and cDNA was synthesized and designed the primer for the ADR-α1, 2 and ADR-β2 gene expression. The protein levels were investigated by Western Blot.

RESULTS

The results showed a high level of three adrenergic expressions in PCO women compared to the control group (p-value <.001), which can be reduced by clonidine. POR group showed a significant decrease in the gene expression of ADR-α1 (p-value = .004) and ADR-α2 (p-value = .003) compared to the control group and clonidine treatment had no effect.

CONCLUSION

The significant increase of three adrenoceptors gene expression and protein levels in CCs culture indicate to the hyperactivity of the ovarian sympathetic nervous system at the receptor levels in women with PCOS, and clonidine confirmed it by reducing this expression. In POR women, the reduction of ADR-α1, 2 expressions maybe lead to the aging process in the ovary.

Leucine-rich alpha-2 glycoprotein 1, high mobility group box 1, matrix metalloproteinase 3 and annexin A1 as biomarkers of ulcerative colitis endoscopic and histological activity

OBJECTIVE

The LRG, HMGB1, MMP3 and ANXA1 proteins have been implicated in different inflammatory pathways in ulcerative colitis (UC), but their role as specific biomarkers of both endoscopic and histological activity has yet to be elucidated. In the present study, we aimed to evaluate the LRG1, HMGB1, MMP3 and ANXA1 as potential serum biomarkers for UC endoscopic and histological activity.

METHODS

This cross-sectional study included UC patients under 5-ASA, and healthy controls (HC) undergoing colonoscopy. Blood and biopsy samples were obtained and endoscopic Mayo sub-score (Ms) was recorded for the UC patients. Intramucosal calprotectin as a marker of histologic activity was evaluated in all biopsy samples and serum LRG1, HMGB1, MMP3 and ANXA1 levels were measured in the blood samples.

RESULTS

The HCs ANXA1 level was lower compared to that of the UC group [P = 0.00, area under the curve (AUC) = 0.881] and so was the HCs MMP3 level compared to that of patients (P = 0.00, AUC = 0.835). The HCs ANXA1 levels were also lower compared to these of the independent Ms groups, even to the Ms = 0 (P = 0.00, AUC = 0.913). UC endoscopic activity was associated with MMP3 levels (r = 0.54, P = 0.000) but not with ANXA1, LRG1 and HMGB1 levels CONCLUSION: Serum ANXA1 is a potential diagnostic biomarker of UC and serum MMP3 is a potential biomarker of UC endoscopic and histological activity.

The Prognostic Impact of Leucine-Rich α-2-Glycoprotein-1 in Cholangiocarcinoma and Its Association With the IL-6/TGF-β1 Axis

BACKGROUND

Leucine-rich α-2-glycoprotein-1 (LRG) has been found to participate in the development of various cancers through its involvement in TGF-β1-induced epithelial-mesenchymal transition (EMT) and/or angiogenesis and can be induced by inflammatory cytokines, such as IL-6. As we previously showed the implication of IL-6/TGF-β axis in EMT of cholangiocarcinoma cells, we herein explored the prognostic impact of LRG in postoperative intrahepatic cholangiocarcinoma (ICC) and assessed the association between tumor LRG and factors such as TGF-β1, IL-6, and the tumor microvessel density.

METHODS

We determined the expression of LRG, IL-6, TGF-β1, and CD31 in cancer tissues from 50 ICC patients by immunohistochemistry and analyzed their association with the prognosis.

RESULTS

The LRG expression was closely associated with recurrence-free survival (RFS) and overall survival (OS) in postoperative ICC. A multivariate Cox regression model indicated that LRG as an independently associated with poor RFS (hazard ratio = 2.4339, P = 0.0354) and OS (hazard ratio = 2.8892, P = 0.0268). The LRG expression was significantly associated with the expression of TGF-β1 (P = 0.0003) and IL-6 (P = 0.0164).

CONCLUSIONS

The upregulation of LRG in tumors was an independent prognostic factor in patients with postoperative ICC. LRG was closely associated with the TGF-β1 expression and seems to be an important member of the IL-6/TGF-β1 axis.

Leucine-rich α2-glycoprotein-1 upregulation in plasma and kidney of patients with lupus nephritis

BACKGROUND

Increased leucine-rich α2-glycoprotein-1 (LRG1) has been observed in various inflammatory and autoimmune diseases. We aimed to explore the expression and role of LRG1 in lupus nephritis (LN).

METHODS

Plasma LRG1 (pLRG1) was measured by enzyme-linked immunosorbent assay in 101 patients with renal biopsy-proven LN and 21 healthy controls (HC). Relationships between pLRG1 and clinical and pathological characteristics were analyzed. The expression of LRG1 in peripheral blood leukocytes and kidney was detected by flow cytometry, immunohistochemistry and immunofluorescence, respectively. Further cell experiments were focused on the role of LRG1.

RESULTS

We found that LRG1 was expressed in plasma, some peripheral blood leukocytes, proximal tubule and several inflammatory cells. The levels of LRG1 in plasma, peripheral blood leukocytes and kidney were elevated in LN patients as compared to HC. Plasma expression levels of LRG1 correlated positively with renal function and renal disease activity, and reflect specific pathologic lesions in the kidneys of patients with LN. Interleukin-1β and interleukin-6, not tumor necrosis factor-α and interferon γ induced the LRG1 expression in human renal tubular epithelial cell line. Moreover, stimulation of recombinant human LRG1 could inhibit late apoptosis, promote proliferation and regulate expression of inflammatory factors and cytokines.

CONCLUSIONS

Plasma expression levels of LRG1 were associated with renal function, disease activity, and pathology in LN. It might also be involved in renal inflammation, proliferation and apoptosis of endothelial cells. LRG1 might be a potential prognosis novel predictor in LN patients.

LRG1 May Accelerate the Progression of ccRCC via the TGF-β Pathway

Clear cell renal cell carcinoma (ccRCC) accounts for 60-70% of renal cell carcinoma (RCC) cases. It is an urgent mission to find more therapeutic targets for advanced ccRCC. Leucine-rich a-2-glycoprotein 1 (LRG1) is a secreted protein associated with a variety of malignancies. Our study focused on the expression and mechanism of LRG1 in ccRCC based on data from The Cancer Genome Atlas (TCGA) and provided primary verification including LRG1 expression detection, LRG1 gene methylation detection, and downstream signaling detection. We found that LRG1 was overexpressed in ccRCC kidney tissue samples, and the methylation level of LRG1 gene was significantly decreased in ccRCC. Moreover, the expression of LRG1 was negatively related to patient survival. Based on our previous study and the verification reported in this article, we propose that demethylation-induced overexpression of LRG1 is likely to accelerate ccRCC progression via the TGF-β pathway.

Novel potential biomarkers for the diagnosis and monitoring of patients with ulcerative colitis

Unambiguously, great progress has been achieved in the unraveling of more pathological pathways implicated in the development and progression of ulcerative colitis during the last decades. Novel effective drugs that have augmented the management armamentarium have been developed alongside this growing comprehension of the disease, rendering mucosal healing not only a feasible but the optimal goal of every therapy. Clinical evaluation, colonoscopy and biomarkers are the tools used by practitioners for the diagnosis and assessment of the status of the disease in order to achieve clinical remission and mucosal healing for their patients. Among these tools, colonoscopy is the gold method for the cause but is still an invasive, high-cost procedure with possible adverse events such as perforation. While clinical evaluation entails much subjectivity, biomarkers are objective, easily reproducible, non-invasive, cheap and potent surrogate tools of mucosal inflammation. Unfortunately, the well-established, currently in use serum biomarkers, such as C-reactive protein, erythrocyte sedimentation rate and others, do not display sufficiently acceptable sensitivity and specificity rates for the diagnosis of ulcerative colitis and, most importantly, do not represent precisely the mucosal inflammation status of the disease. Therefore, the discovery of new serum biomarkers has been the cause of several studies attempting to discover an "optimal" serum biomarker during the recent years. After thorough research, collection and examination of current data, this review focuses on and selectively presents promising, potential, novel serum biomarkers of ulcerative colitis as they are indicated by studies on the patient over the last years.

Evaluation of a biomarker for the diagnosis of pancreas cancer using an animal model

Many approaches have been taken to identify new biomarkers of pancreatic ductal carcinoma (PDC). Since animal models can be sampled under controlled conditions, better standardization is possible compared with heterogeneous human studies. Transgenic rats with conditional activation of oncogenic RAS in pancreatic tissue develop PDC that closely resembles the biological and histopathological features of human PDC. Using this model, we evaluated the usefulness of leucine-rich α2-glycoprotein-1 (LRG-1) as a serum marker. In this study, we found that LRG-1 was overexpressed in rat PDC compared with normal pancreas tissue of the control rats. Serum levels of LRG-1 were also significantly higher in rats bearing PDC than in controls. Importantly, chronic pancreatitis in male Wistar Bonn/Kobori rats, which is a widely accepted as a model of chronic pancreatitis, did not cause serum levels of LRG-1 to become elevated. These results strongly support serum LRG-1 as a candidate biomarker for noninvasive diagnosis of PDC. Our models of pancreas cancer provide a useful strategy for evaluation of candidate markers applicable to human cancer.

Elevated plasma and vitreous levels of leucine-rich-α2-glycoprotein are associated with diabetic retinopathy progression

PURPOSE

To investigate the association of plasma and vitreous leucine-rich-α2-glycoprotein (LRG1) with diabetic retinopathy (DR) progression.

METHODS

A total of 86 outpatients and 33 inpatients were recruited. Outpatients with type 2 diabetes mellitus (T2DM) were classified as T2DM without DR (n = 22), nonproliferative DR (NPDR) (n = 20) and proliferative DR (PDR) (n = 22) based on international clinical DR severity scales. A total of 86 plasma and 33 vitreous samples were collected and subjected to enzyme-linked immunosorbent assay. The diagnostic value of plasma LRG1 was tested using receiver operating characteristic (ROC) curves.

RESULTS

Plasma LRG1 in PDR patients (9025 ± 1870 pg/ml) was significantly increased as compared with controls (5975 ± 2022 pg/ml), T2DM without DR (6550 ± 2359 pg/ml) and NPDR patients (6550 ± 2359 pg/ml) (p < 0.0001). Vitreous LRG1 in PDR patients was elevated by approximately 4.3-fold than that in controls (562.1 ± 273.5 ng/ml versus 130.0 ± 102.8 ng/ml, p = 0.000). The area under the ROC curve value for plasma LRG1 was 0.786 (p < 0.0001). The maximal Youden index was 0.4372 and the optimal cut-off value of LRG1 was 7357.043 pg/ml with 81.82% sensitivity and 61.90% specificity.

CONCLUSION

Plasma and vitreous LRG1 levels were elevated in patients with PDR. Leucine-rich-α2-glycoprotein (LRG1) might be a potential risk-warning marker for PDR.

LRG‑1 enhances the migration of thyroid carcinoma cells through promotion of the epithelial‑mesenchymal transition by activating MAPK/p38 signaling

Leucine-rich-alpha-2-glycoprotein 1 (LRG-1) has been reported to be associated with multiple malignancies. However, its participation in thyroid carcinoma progression remains unclear. In the present study, the biological function and underlying molecular mechanisms of LRG-1 in thyroid carcinoma were investigated. It was found that LRG-1 was overexpressed in thyroid carcinoma tissues, and high LRG-1 expression predicted poor patient survival and late tumor stage. As shown in the mouse xenograft study, knockdown of LRG-1 significantly attenuated thyroid cancer growth in vivo. Based on wound healing, Transwell, proliferation and apoptosis assays, it was found that the knockdown of LRG-1, using shLRG-1, inhibited cell migration and invasion, but did not affect proliferation and apoptosis in thyroid cancer cells. Furthermore, LRG-1 also induced epithelial-mesenchymal transition (EMT) in thyroid carcinoma cells. Western blot analysis revealed that this tumor-promoting bioactivity of LRG-1 was attributed to its selective activation of MAPK/p38 signaling. All of these findings indicate that LRG-1 plays a deleterious role in the progression of thyroid carcinoma. LRG-1 may serve as a promising biomarker for predicting prognosis in thyroid carcinoma patients, and LRG-1-based therapy may be developed into a novel strategy for the treatment of thyroid carcinoma.

Plasma proteome profiling reveals differentially expressed lipopolysaccharide-binding protein among leptospirosis patients

BACKGROUND

Human leptospirosis, or commonly known as "rat urine disease" is a zoonotic disease that is caused by the bacteria called Leptospira sp. The incidence rate of leptospirosis has been under-reported due to its unspecific clinical symptoms and the limitations of current laboratory diagnostic methods. Leptospirosis can be effectively treated with antibiotics in the early stage, and it is a curable disease but the accuracy to diagnose the infection is rarely achieved.

METHODS

The present pilot study investigated plasma protein profiles of leptospirosis patients and compared them against two control groups which consisted of dengue patients and healthy individuals. The plasma protein digests were analyzed using shotgun approach by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Protein abundances were estimated from the exponentially modified protein abundance index (emPAI) values. Plasma proteins in leptospirosis patients with at least two-fold differential expression compared to dengue and healthy control groups (p < 0.05, ANOVA) were identified.

RESULTS

Lipopolysaccharide (LPS)-binding protein (LBP) was found to be the only protein that has significant different expression between leptospirosis and the two control groups. The expression levels of leucine-rich alpha-2-glycoprotein (LRG1) and alpha-1-antichymotrypsin (ACT) were different significantly between leptospirosis and healthy group but not to the dengue control group.

CONCLUSION

This is the first plasma proteome-based study on leptospirosis that reports the differential expression of LBP compared to both dengue and healthy controls, which has not been previously reported in the context of leptospirosis.

Silibinin inhibits ultraviolet B radiation-induced mast cells recruitment and bone morphogenetic protein 2 expression in the skin at early stages in Ptch(+/-) mouse model of basal cell carcinoma

Around 80% of nonmelanoma skin cancers (NMSCs) are basal cell carcinoma (BCC), still studies evaluating the efficacy of chemopreventive agents during early stage/s of BCC development are lacking. Accordingly, utilizing the well-established patched (Ptch)+/- mouse model of ultraviolet B (UVB) radiation-induced BCC formation, we excised skin samples from UVB exposed Ptch+/- and Ptch+/+ mice before tumor formation to study the promotion/progression of BCC and to determine the efficacy and target/s of silibinin, a well-known skin cancer chemopreventive agent. UVB exposure for 1 month increased the number of mast cells in Ptch+/- mice by ~48% (P < 0.05), which was completely inhibited by silibinin. Polymerase chain reaction profiler array analysis of skin samples showed strong molecular differences between Ptch+/+ and Ptch+/- mice which were either unexposed or UVB irradiated+/- silibinin treatment. Most notably, silibinin treatment significant decreased the expression of BMP-2, Bbc3, PUMA, and Ccnd1 in Ptch+/- mice irradiated with silibinin + UVB. Additional studies showed that silibinin targets UVB-induced expression of bone morphogenetic protein 2 (BMP-2) in Ptch+/- mouse skin. Last, our studies found that silibinin strongly attenuates UVB-induced BMP-2 expression and DNA damage in Ptch+/- mouse skin ex vivo only after single UVB exposure. Together, our results suggest a possible role of mast cell recruitment and BMP-2 activation in the early stages of BCC development; these are strongly inhibited by silibinin suggesting its possible chemopreventive efficacy against BCC formation in long-term UVB exposure regimen.

LRG1 Promotes Diabetic Kidney Disease Progression by Enhancing TGF-β-Induced Angiogenesis

BACKGROUND

Glomerular endothelial dysfunction and neoangiogenesis have long been implicated in the pathogenesis of diabetic kidney disease (DKD). However, the specific molecular pathways contributing to these processes in the early stages of DKD are not well understood. Our recent transcriptomic profiling of glomerular endothelial cells identified a number of proangiogenic genes that were upregulated in diabetic mice, including leucine-rich α-2-glycoprotein 1 (LRG1). LRG1 was previously shown to promote neovascularization in mouse models of ocular disease by potentiating endothelial TGF-β/activin receptor-like kinase 1 (ALK1) signaling. However, LRG1's role in the kidney, particularly in the setting of DKD, has been unclear.

METHODS

We analyzed expression of LRG1 mRNA in glomeruli of diabetic kidneys and assessed its localization by RNA in situ hybridization. We examined the effects of genetic ablation of Lrg1 on DKD progression in unilaterally nephrectomized, streptozotocin-induced diabetic mice at 12 and 20 weeks after diabetes induction. We also assessed whether plasma LRG1 was associated with renal outcome in patients with type 2 diabetes.

RESULTS

LRG1 localized predominantly to glomerular endothelial cells, and its expression was elevated in the diabetic kidneys. LRG1 ablation markedly attenuated diabetes-induced glomerular angiogenesis, podocyte loss, and the development of diabetic glomerulopathy. These improvements were associated with reduced ALK1-Smad1/5/8 activation in glomeruli of diabetic mice. Moreover, increased plasma LRG1 was associated with worse renal outcome in patients with type 2 diabetes.

CONCLUSIONS

These findings identify LRG1 as a potential novel pathogenic mediator of diabetic glomerular neoangiogenesis and a risk factor in DKD progression.