Leucine-rich Α-2-glycoprotein 1 Research Articles

Diet-enhanced LRG1 expression promotes insulin hypersecretion and ER stress in pancreatic beta cells.

Upregulation of serum leucine-rich α-2-glycoprotein 1 (LRG1) has been implicated in diet-induced obesity and metabolic disorders. However, its specific hormonal actions remain unclear. This study aimed to determine whether diet-enhanced serum LRG1 levels promote hyperinsulinaemia by directly stimulating insulin secretion from pancreatic beta cells. Human serum samples were obtained from individuals (both male and female) undergoing plastic surgery. Male C57BL/6 wild-type and Lrg1 whole-body knockout (Lrg1KO) mice were fed a 45% high-fat diet, with serum samples collected every 2 weeks to monitor LRG1 and insulin levels throughout diet-induced obesity. MIN6 beta cells were used to investigate the effects of LRG1 on insulin secretion and intracellular Ca2+ release. Antibodies targeting various LRG1 epitopes were used to neutralise LRG1 stimulation in MIN6 cells, and their effectiveness was tested in vivo to assess their ability to prevent LRG1-induced hyperinsulinaemia. We observed a significant positive association between human serum LRG1 levels and both age and BMI, with elevated levels observed in individuals with vs without type 2 diabetes. In mice fed a high-fat diet, LRG1 upregulation in serum was associated with hyperinsulinaemia. Lrg1 knockout protected mice from diet-induced islet hyperplasia and the loss of beta cell mass. Furthermore, neutralising LRG1 activity prevented the onset of diet-induced hyperinsulinaemia and preserved glucose tolerance. Mechanistically, LRG1 induces inositol triphosphate (IP3) production and intracellular Ca2+ release from the endoplasmic reticulum (ER) in a phospholipase C (PLC)-dependent manner, leading to excessive insulin secretion and ER stress in MIN6 beta cells. In summary, this study identifies LRG1 as a significant contributor to hyperinsulinaemia and beta cell dysfunction. Targeting LRG1 activity emerges as a promising therapeutic approach for addressing diet-induced beta cell dysfunction and managing type 2 diabetes.

LRG1-Targeted Nintedanib Delivery for Enhanced Renal Fibrosis Mitigation.

Renal fibrosis lacks effective nephroprotective drugs in clinical settings due to poor accumulation of therapeutic agents in damaged kidneys, underscoring the urgent need for advanced renal-targeted delivery systems. Herein, we exploited the significantly increased expression of the leucine-rich α-2 glycoprotein 1 (LRG1) protein during renal fibrosis to develop a novel drug delivery system. Our engineered nanocarrier, DENNM, preferentially targets fibrotic kidneys via the decorated ET peptide's high affinity for LRG1. Once internalized by damaged renal cells, DENNM releases its encapsulated nintedanib, triggered by the active caspase-3 protease, disrupting the nanomedicine's structural integrity. The released nintedanib effectively reduces the level of expression of the extracellular matrix and impedes the progression of renal fibrosis by inhibiting the transforming growth factor-β (TGF-β)-Smad2/3 pathway. Our comprehensive in vitro and in vivo studies validate DENNM's antifibrotic efficacy, emphasizing LRG1's potential in renal targeted drug delivery and introducing an innovative approach to nanomedicine for treating renal fibrosis.

Manejo da Doença Renal Crônica: Importância do diagnóstico precoce e monitoramento contínuo

Introduction: Chronic Kidney Disease (CKD) is a serious public health problem, affecting about 10% of the world's population. It is characterized by progressive and irreversible loss of kidney function, often caused by diabetes mellitus and hypertension. Early diagnosis of CKD is essential to slow its progression, improve patients' quality of life, and reduce treatment costs. Markers such as glomerular filtration rate (GFR) and albuminuria are critical for early detection. Methods: A comprehensive literature review was conducted on advances in early diagnosis and continuous monitoring of CKD. The search included studies published between 2013 and 2023, indexed in the PubMed, Lilacs, and SciELO databases, using terms such as "Chronic Kidney Disease management", "early diagnosis", and "continuous monitoring". 20 articles were selected after applying strict inclusion and exclusion criteria, with the final analysis of the full texts. Results: The analysis of the selected studies highlighted the importance of solid protocols for early diagnosis and continuous monitoring in the management of CKD. The introduction of new biomarkers, such as Leucine-Rich α-2-Glycoprotein 1 (LRG1), complements traditional methods, offering more accurate detection of CKD. In addition, remote monitoring via telemedicine has been shown to be effective in reducing hospitalizations and improving treatment adherence, particularly in patients on home dialysis. The combination of these strategies not only improves patients' clinical outcomes, but also reduces the financial burden on health systems. Conclusion: The review highlighted the need for robust protocols for early diagnosis and continuous monitoring in the management of CKD. The integration of new biomarkers and telemedicine technologies represents a significant advance, allowing for more effective and economically viable interventions. Such practices can improve patients' quality of life and provide a more sustainable approach to health systems, aligning with public health objectives.

Targeting Gsk3a reverses immune evasion to enhance immunotherapy in hepatocellular carcinoma

BackgroundImmune escape is an important feature of hepatocellular carcinoma (HCC). The overall response rate of immune checkpoint inhibitors (ICIs) in HCC is still limited. Revealing the immune regulation mechanisms and...

Leucine rich α2 glycoprotein 1 derived from malignant pleural mesothelioma cells facilitates macrophage M2 phenotypes

Background: Macrophages constitute the main part of infiltrating immune cells in Malignant pleural mesothelioma (MPM) and abnormally high ratios of M2 macrophages are present in both pleural effusion and tissue samples of MPM patients. Whether MPM cells affect formation of M2 macrophages is poorly understood. In this study, we focused on identification of MPM-cells-derived soluble factors with M2-promoting effects. Methods: Media of malignant pleural mesothelioma cells were collected and soluble factors affecting macrophages were analyzed by mass spectrometry. TGF-β receptor inhibitor SB431542 was used as the entry point to explore the downstream mechanism of action by qRT-PCR, WB and immunofluorescence. Results: The serum-free culture media collected from the human MPM cells Meso1 and Meso2 significantly enhanced expression of the M2 signature molecules including IL-10, TGF-β and CD206 in the human macrophages THP-1, while the culture medium of the human MPM cells H2452 did not show such M2-promoting effects. Analysis of proteins by mass spectrometry and ELISA suggested that Leucine rich α2 glycoprotein 1(LRG1) was a potential candidate. LRG1 time- and dose-dependently increased expression of the M2 signature molecules, confirming its M2-promoting effects. Furthermore, LRG1’s M2-promoting effects were reduced by the TGF-β receptor inhibitor SB431542, and LRG1 increased phosphorylation of Smad2, indicating that M2-promoting effects of LRG1 were via the TGF-β receptor/Smad2 signaling pathway. Conclusions: Our results provide a potential M2-promoting new member, LRG1, which contributes to the immune escape of MPM via the TGF-β receptor/Smad2 signaling pathway.

Targeted degradation of LRG1 to attenuate renal fibrosis

Leucine-rich α-2 glycoprotein 1 (LRG1), a secreted glycoprotein, has been identified as significantly upregulated in renal fibrosis, potentially exacerbating the condition by enhancing TGF-β-Smad3-dependent signaling pathways. Herein, utilizing our developed LRG1-targeting peptide for LRG1 recruitment and lenalidomide for E3 ubiquitin ligase engagement, we developed an advanced proteolysis targeting chimera, ETTAC-2, specifically designed for LRG1 degradation. Our cellular degradation assays validated that ETTAC-2 effectively degraded LRG1 through a proteasome-dependent mechanism, achieving half-maximal degradation at a concentration of 8.38 µM. Furthermore, anti-fibrotic experiments conducted both in vitro and in vivo revealed that ETTAC-2 efficiently induced LRG1 degradation in fibrotic kidneys. This action effectively inhibited the TGF-β-Smad3 signaling pathway and diminished the secretion of fibrosis-associated proteins, consequently attenuating the progression of renal fibrosis. Our study highlights the pivotal role of LRG1 in renal fibrosis and positions ETTAC-2 as a promising therapeutic candidate for targeted LRG1 intervention.

LRG1 loss effectively restrains glomerular TGF-β signaling to attenuate diabetic kidney disease

Transforming growth factor (TGF)-β signaling is a well-established pathogenic mediator of diabetic kidney disease (DKD). However, owing to its pleiotropic actions, its systemic blockade is not therapeutically optimal. The expression of TGF-β signaling regulators can substantially influence TGF-β's effects in a cell- or context-specific manner. Among these, leucine-rich α2-glycoprotein 1 (LRG1) is significantly increased in glomerular endothelial cells (GECs) in DKD. As LRG1 is a secreted molecule that can exert autocrine and paracrine effects, we examined the effects of LRG1 loss in kidney cells in diabetic OVE26 mice by single-cell transcriptomic analysis. Gene expression analysis confirmed a predominant expression of Lrg1 in GECs, which further increased in diabetic kidneys. Loss of Lrg1 led to the reversal of angiogenic and TGF-β-induced gene expression in GECs, which were associated with DKD attenuation. Notably, Lrg1 loss also mitigated the increased TGF-β-mediated gene expression in both podocytes and mesangial cells in diabetic mice, indicating that GEC-derived LRG1 potentiates TGF-β signaling in glomerular cells in an autocrine and paracrine manner. Indeed, a significant reduction in phospho-Smad proteins was observed in the glomerular cells of OVE26 mice with LRG1 loss. These results indicate that specific antagonisms of LRG1 may be an effective approach to curb the hyperactive glomerular TGF-β signaling to attenuate DKD.

Quantitative Proteomic Analysis Reveals Functional Alterations of the Peripheral Immune System in Colorectal Cancer

Colorectal cancer (CRC) is characterized by high morbidity, high mortality, and limited response to immunotherapies. The peripheral immune system is an important component of tumor immunity, and enhancements of peripheral immunity help to suppress tumor progression. However, the functional alterations of the peripheral immune system in CRC are unclear. Here, we used mass spectrometry-based quantitative proteomics to establish a protein expression atlas for the peripheral immune system in CRC, including plasma and five types of immune cells (CD4+ T cells, CD8+ T cells, monocytes, natural killer cells, and B cells). Synthesizing the results of the multidimensional analysis, we observed an enhanced inflammatory phenotype in CRC, including elevated expression of plasma inflammatory proteins, activation of the inflammatory pathway in monocytes, and increased inflammation-related ligand-receptor interactions. Notably, we observed tumor effects on peripheral T cells, including altered cell subpopulation ratios and suppression of cell function. Suppression of CD4+ T cell function is mainly mediated by high expression levels of protein tyrosine phosphatases. Among them, the expression of protein tyrosine phosphatase receptor type J (PTPRJ) gradually increased with CRC progression; knockdown of PTPRJ in vitro could promote T cell activation, thereby enhancing peripheral immunity. We also found that the combination of leucine-rich α-2 glycoprotein 1 (LRG1) and apolipoprotein A4 (APOA4) had the best predictive ability for colorectal cancer and has the potential to be a biomarker. Overall, this study provides a comprehensive understanding of the peripheral immune system in CRC. It also offers insights regarding the potential clinical utilities of these peripheral immune characteristics as diagnostic indicators and therapeutic targets.

The importance of leucine-rich α-2 glycoprotein-1 in acute calculus cholecystitis.

The aim of this prospective, single-center cohort study was to analyze serum leucine-rich α-2-glycoprotein-1 (LRG1) expression in patients with acute cholecystitis (AC) and to investigate its variation depending on symptom duration. Participants were divided into patients with AC and a healthy control group. At the time of diagnosis, blood samples were collected, and symptom onset times were questioned. Collected serum LRG1 levels were measured. 30 patients and 30 healthy volunteers were included in the study. LRG1 (p=0.008), white blood cells (WBC) (p<0.001), platelet (p=0.003), neutrophil (p<0.001), lymphocyte (p=0.001), and CRP (p=0.014) were significantly different in AC patients vs. the control group. When the correlations of serum laboratory values with the time of onset of symptoms were compared, LRG1 (p<0.001) was significantly correlated, while no significant correlation was observed in C-reactive protein (CRP) (p=0.572), WBC (p=0.155), and neutrophil (p=0.155). LRG1 expression increases after 24 hours in AC patients. Due to its correlation with symptom duration, we believe it can be helpful for timing cholecystectomy.

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.

Plasma leucine-rich α-2 glycoprotein 1 in ST-elevation myocardial infarction: vertical variation, correlation with T helper 17/regulatory T ratio, and predictive value on major adverse cardiovascular events.

Leucine-rich α-2 glycoprotein 1 (LRG1) promotes inflammation and myocardial injury, but its clinical role in ST-elevation myocardial infarction (STEMI) is rarely disclosed. Herein, this prospective study aimed to explore the value of plasma LRG1 at different time points to predict major adverse cardiovascular event (MACE) risk in patients with STEMI. In total, 209 patients with STEMI were enrolled for determining plasma LRG1 at admission and on day (D)1/D7/D30 after admission via enzyme-linked immunosorbent assay, as well as for determination of peripheral blood T helper 17 (Th17) cells and regulatory T (Treg) cells by flow cytometry. In addition, plasma LRG1 was obtained from 30 healthy controls at enrollment. LRG1 was increased in patients with STEMI at admission compared with healthy controls (P < 0.001). In patients with STEMI, LRG1 varied at different time points (P < 0.001), which elevated from admission to D1, and gradually declined thereafter. LRG1 at admission was positively associated with Th17 cells (P = 0.001) and Th17/Treg ratio (P = 0.014). LRG1 at admission (P = 0.013), D1 (P = 0.034), D7 (P = 0.001), and D30 (P = 0.010) were increased in patients with MACE compared with those without. LRG1 at D7 exhibited good ability to estimate MACE risk (area under curve = 0.750, 95% confidence interval = 0.641-0.858). LRG1 at admission > 60 μg/ml (P = 0.031) and D7 > 60 μg/ml (P = 0.018) were linked with increased accumulating MACE. Importantly, LRG1 at D7 > 60 μg/ml was independently correlated with increased MACE risk (hazard ratio = 5.216, P = 0.033). Plasma LRG1 increases from admission to D1 and gradually declines until D30, which positively links with Th17 cells and MACE risk in patients with STEMI.

Leucine-rich alpha-2-glycoprotein 1 affects bone destruction via IL-6 in mouse periodontitis model.

To investigate the production of leucine-rich α-2-glycoprotein-1 (LRG1) in periodontitis patients and its effectiveness as a new diagnostic marker for periodontitis. In vitro experiments were conducted to analyze LRG1 mRNA expression in human gingival epithelial cells and fibroblasts via quantitative real-time PCR. Invivo experiments were conducted to analyze LRG1 localization in periodontitis patients. The correlation between the serum LRG1 levels and alveolar bone resorption in the mouse periodontitis model was also investigated. A positive correlation existed between the periodontal inflamed surface area and serum LRG1 levels (Spearman's rank correlation coefficient: 0.60). LRG1 mRNA expression in human gingival epithelial cells and fibroblasts was upregulated by Porphyromonas gingivalis stimulation or tumor necrosis factor-α stimulation. Interleukin-6 in human gingival epithelial cells and fibroblasts induced the production of LRG1 and transforming growth factor-β. LRG1 levels in the periodontal tissue and serum in the periodontitis model were higher than those in control mice. LRG1 local administration resulted in alveolar bone resorption, whereas the administration of interleukin-6R antibody inhibited bone resorption. LRG1 levels in serum and periodontal tissue are upregulated in periodontitis and are implicated in periodontal tissue destruction through interleukin-6 production.

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

BackgroundLeucine-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.MethodsSerum 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.ResultsMean 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).ConclusionsThis study highlights the potential of LRG-1 as an independent prognostic biomarker in patients with early BC.

Proteomic Biomarkers for the Prediction of Transition to Psychosis in Individuals at Clinical High Risk: A Multi-cohort Model Development Study.

Psychosis risk prediction is one of the leading challenges in psychiatry. Previous investigations have suggested that plasma proteomic data may be useful in accurately predicting transition to psychosis in individuals at clinical high risk (CHR). We hypothesized that an a priori-specified proteomic prediction model would have strong predictive accuracy for psychosis risk and aimed to replicate longitudinal associations between plasma proteins and transition to psychosis. This study used plasma samples from participants in 3 CHR cohorts: the North American Prodrome Longitudinal Studies 2 and 3, and the NEURAPRO randomized control trial (total n = 754). Plasma proteomic data were quantified using mass spectrometry. The primary outcome was transition to psychosis over the study follow-up period. Logistic regression models were internally validated, and optimism-corrected performance metrics derived with a bootstrap procedure. In the overall sample of CHR participants (age: 18.5, SD: 3.9; 51.9% male), 20.4% (n = 154) developed psychosis within 4.4 years. The a priori-specified model showed poor risk-prediction accuracy for the development of psychosis (C-statistic: 0.51 [95% CI: 0.50, 0.59], calibration slope: 0.45). At a group level, Complement C8B, C4B, C5, and leucine-rich α-2 glycoprotein 1 (LRG1) were associated with transition to psychosis but did not surpass correction for multiple comparisons. This study did not confirm the findings from a previous proteomic prediction model of transition from CHR to psychosis. Certain complement proteins may be weakly associated with transition at a group level. Previous findings, derived from small samples, should be interpreted with caution.

Association Between Plasma LRG1 and Lower Cognitive Function in Asians With Type 2 Diabetes Mellitus.

Leucine-rich α-2-glycoprotein 1 (LRG1) has been implicated in the pathogenesis of diabetic complications, but its association with cognitive function remains unclear. Our primary objective is to investigate the longitudinal association between LRG1 and cognitive function in patients with type 2 diabetes mellitus (T2DM). Secondarily, we determine the causal relationship using Mendelian randomization (MR) and the role of arterial stiffness as a potential mediator. T2DM patients (n = 1039; age = 64.1 ± 6.4 years) were followed-up for 5.3 ± 1.2 years. Plasma LRG1 was measured at baseline using enzyme-linked immunosorbent assay. Baseline and follow-up cognitive function was assessed using Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). One-sample MR was performed with rs4806985 as plasma LRG1-associated single-nucleotide polymorphism. Mediation analysis was performed to examine if pulse wave velocity (PWV), an arterial stiffness index, mediated the association between plasma LRG1 and follow-up cognitive function. Elevated baseline natural log (Ln)-transformed LRG1 was inversely associated with baseline and follow-up RBANS total score with adjusted coefficients -1.38 (95% CI -2.55 to -.21; P = .021) and -1.38 (95% CI -2.70 to -.07; P = .039), respectively. Genetically predicted higher levels of plasma LRG1 was associated with lower follow-up RBANS total score with coefficient -7.44 (95% CI -14.14 to -.74; P = .030) per unit increase in LnLRG1. Higher PWV accounted for 27.7% of the association between LnLRG1 and follow-up RBANS total score. Baseline plasma LRG1 was associated with lower cognitive function at follow-up in patients with T2DM, mediated by PWV. MR analysis provided evidence of an association between genetically influenced plasma LRG1 and lower cognitive function at follow-up.

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

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. 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. 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. 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.

Keratinocyte-to-macrophage communication exacerbate psoriasiform dermatitis via LRG1-enriched extracellular vesicles.

Rationale: Macrophage-associated inflammation and keratinocytes excessive proliferation and inflammatory cytokines secretion induced by stimulation play an important role in the progression of psoriasiform dermatitis. However, how these two types of cells communicate remains obscure. Methods: We induced a mouse model with experimental psoriasiform dermatitis by Imiquimod (IMQ). To investigate whether damaged keratinocytes promote macrophage polarization and accelerate skin lesions by releasing extracellular vesicle (EV), purified EV were isolated from the primary epidermis of 5-day IMQ-induced psoriasiform dermatitis model mice, and then fluorescence-labeled the EV with PKH67. The EV was injected into the skin of mice treated with IMQ or vehicle 2 days in situ. In addition, we established a co-culture system of the human monocytic cell line (THP-1) and HaCaT, and THP-1/HaCaT conditioned media culture model in vitro respectively. Subsequently, we evaluated the effect of Leucine-rich α-2-glycoprotein 1 (LRG1)-enriched EV on macrophage activation. Results: We demonstrated macrophages can significantly promote keratinocyte inflammation and macrophage polarization may be mediated by intercellular communication with keratinocytes. Interestingly, IMQ-induced 5-day, keratinocyte-derived EV recruited macrophage and enhanced the progression of skin lesions. Similar to results in vivo, EV released from M5-treated HaCaT significantly promotes Interleukin 1β (IL-1β) and Tumor necrosis factor α (TNF-α) expression of THP-1 cells. Importantly, we found that LRG1-enriched EV regulates macrophages via TGF beta Receptor 1 (TGFβR1) dependent process. Conclusion: Our findings indicated a novel mechanism for promoting psoriasiform dermatitis, which could be a potential therapeutic target.

Leucine-Rich Alpha-2 Glycoprotein 1 Accumulates in Complicated Atherosclerosis and Promotes Calcification.

Atherosclerosis is the primary cause of cardiovascular disease. The development of plaque complications, such as calcification and neo-angiogenesis, strongly impacts plaque stability and is a good predictor of mortality in patients with atherosclerosis. Despite well-known risk factors of plaque complications, such as diabetes mellitus and chronic kidney disease, the mechanisms involved are not fully understood. We and others have identified that the concentration of circulating leucine-rich α-2 glycoprotein 1 (LRG1) was increased in diabetic and chronic kidney disease patients. Using apolipoprotein E knockout mice (ApoE-/-) (fed with Western diet) that developed advanced atherosclerosis and using human carotid endarterectomy, we showed that LRG1 accumulated into an atherosclerotic plaque, preferentially in calcified areas. We then investigated the possible origin of LRG1 and its functions on vascular cells and found that LRG1 expression was specifically enhanced in endothelial cells via inflammatory mediators and not in vascular smooth muscle cells (VSMC). Moreover, we identified that LRG1 was able to induce calcification and SMAD1/5-signaling pathways in VSMC. In conclusion, our results identified for the first time that LRG1 is a direct contributor to vascular calcification and suggest a role of this molecule in the development of plaque complications in patients with atherosclerosis.

Relationship between plasma leucine-rich α-2-glycoprotein 1 and urinary albumin excretion in patients with type 2 diabetes.

To explore the relationship between plasma leucine-rich α-2-glycoprotein 1 (LRG1) level and the degree of urinary albumin excretion in patients with type 2 diabetes. We evaluated 332 patients with type 2 diabetes in a cross-sectional study. The plasma LRG1 level differed significantly according to the quartiles of urinary albumin excretion (Q1 [<7.7 mg/g], 17.1 μg/mL; Q2 [7.7-15.0 mg/g], 17.5 μg/mL; Q3 [15.1-61.4 mg/g], 18.6 μg/mL; Q4 [≥61.5 mg/g], 22.3 μg/mL; p for trend = 0.003) under adjustment with other covariates. A positive correlation was found between plasma LRG1 level and urinary albumin excretion (ρ = 0.256, p <0.001). According to a multivariate model, the association between LRG1 and urinary albumin excretion remained significant, under adjustment for confounding factors (β = 0.285, p <0.001). Plasma LRG1 level was independently associated with urinary albumin excretion in patients with type 2 diabetes. This study suggests that LRG1 may be associated with increased excretion of urinary albumin in the early stages of diabetic nephropathy.

Biomarkers in the Pathogenesis, Diagnosis, and Treatment of Systemic Sclerosis.

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by vascular damage, vasoinstability, and decreased perfusion with ischemia, inflammation, and exuberant fibrosis of the skin and internal organs. Biomarkers are analytic indicators of the biological and disease processes within an individual that can be accurately and reproducibly measured. The field of biomarkers in SSc is complex as recent studies have implicated at least 240 pathways and dysregulated proteins in SSc pathogenesis. Anti-nuclear antibodies (ANA) are classical biomarkers with well-described clinical classifications and are present in more than 90% of SSc patients and include anti-centromere, anti-Th/To, anti-RNA polymerase III, and anti-topoisomerase I antibodies. Transforming growth factor-β (TGF-β) is central to the fibrotic process of SSc and is intimately intertwined with other biomarkers. Tyrosine kinases, interferon-1 signaling, IL-6 signaling, endogenous thrombin, peroxisome proliferator-activated receptors (PPARs), lysophosphatidic acid receptors, and amino acid metabolites are new biomarkers with the potential for developing new therapeutic agents. Other biomarkers implicated in SSc-ILD include signal transducer and activator of transcription 4 (STAT4), CD226 (DNAX accessory molecule 1), interferon regulatory factor 5 (IRF5), interleukin-1 receptor-associated kinase-1 (IRAK1), connective tissue growth factor (CTGF), pyrin domain containing 1 (NLRP1), T-cell surface glycoprotein zeta chain (CD3ζ) or CD247, the NLR family, SP-D (surfactant protein), KL-6, leucine-rich α2-glycoprotein-1 (LRG1), CCL19, genetic factors including DRB1 alleles, the interleukins (IL-1, IL-4, IL-6, IL-8, IL-10 IL-13, IL-16, IL-17, IL-18, IL-22, IL-32, and IL-35), the chemokines CCL (2,3,5,13,20,21,23), CXC (8,9,10,11,16), CX3CL1 (fractalkine), and GDF15. Adiponectin (an indicator of PPAR activation) and maresin 1 are reduced in SSc patients. A new trend has been the use of biomarker panels with combined complex multifactor analysis, machine learning, and artificial intelligence to determine disease activity and response to therapy. The present review is an update of the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.