Reduced serum corin levels in patients with osteoporosis

Deficiencies in corin and atrial natriuretic peptide-mediated signaling impair endochondral ossification in bone development

Corin is a protease that activates atrial natriuretic peptide (ANP), a hormone in cardiovascular homeostasis. Structurally, ANP is similar to C-type natriuretic peptide (CNP) crucial in bone development. Here, we examine the role of corin and ANP in chondrocyte differentiation and bone formation. We show that in Corin and Nppa (encoding ANP) knockout (KO) mice, chondrocyte differentiation is impaired, resulting in shortened limb long bones. In adult mice, Corin and Nppa deficiency impairs bone density and microarchitecture. Molecular studies in cartilages from newborn Corin and Nppa KO mice and in cultured chondrocytes indicate that corin and ANP act in chondrocytes via cGMP-dependent protein kinase G signaling to inhibit mitogen-activated protein kinase phosphorylation and stimulate glycogen synthase kinase-3β phosphorylation and β-catenin upregulation. These results indicate that corin and ANP signaling regulates chondrocyte differentiation in bone development and homeostasis, suggesting that enhancing ANP signaling may improve bone quality in patients with osteoporosis.

Systematic transcriptome profiling of hPSC-derived osteoblasts unveils CORIN's mastery in governing osteogenesis through CEBPD modulation

The commitment of stem cells to differentiate into osteoblasts is a highly regulated and complex process that involves the coordination of extrinsic signals and intrinsic transcriptional machinery. While rodent osteoblastic differentiation has been extensively studied, research on human osteogenesis has been limited by cell sources and existing models. Here, we systematically dissect human pluripotent stem cell-derived osteoblasts to identify functional membrane proteins and their downstream transcriptional networks involved in human osteogenesis. Our results reveal an enrichment of type II transmembrane serine protease CORIN in humans but not rodent osteoblasts. Functional analyses demonstrated that CORIN depletion significantly impairs osteogenesis. Genome-wide chromatin immunoprecipitation enrichment and mechanistic studies show that p38 MAPK-mediated CCAAT enhancer binding protein delta (CEBPD) upregulation is required for CORIN-modulated osteogenesis. Contrastingly, the type I transmembrane heparan sulfate proteoglycan SDC1 enriched in mesenchymal stem cells exerts a negative regulatory effect on osteogenesis through a similar mechanism. Chromatin immunoprecipitation-seq, bulk and single-cell transcriptomes, and functional validations indicated that CEBPD plays a critical role in controlling osteogenesis. In summary, our findings uncover previously unrecognized CORIN-mediated CEBPD transcriptomic networks in driving human osteoblast lineage commitment.

Plasma Corin: A New Biochemical Marker for Polycystic Ovary Syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder. Atrial natriuretic peptide (ANP) is a risk factor for PCOS. Corin protein has an essential role in ANP synthesis. This study aimed to evaluate corin as a sensitive biomarker for PCOS.

MATERIALS AND METHODS

A case-control study was conducted with 70 PCOS patients and 70 healthy females. Plasma Corin levels were quantified using enzyme-linked immunosorbent assay.

RESULTS

The median plasma corin levels in PCOS patients and controls were 1785 and 822.5 pg/mL, respectively. Plasma corin levels were significantly elevated in PCOS patients than in the controls (p < 0.001). The optimal cut-off value was set at 1186 pg/mL. The sensitivity and specificity of Corin were 100% and 97.1%, respectively. Plasma corin levels were surrogate predictors for infertility in women with PCOS. It had an odds ratio of 5.9 (95% confidence interval: 1.1-32.7) (p = 0.04). Plasma corin levels were more highly detected in patients with PCOS than in the controls.

CONCLUSION

Plasma corin level has reasonable diagnostic interpretation for PCOS. Corin appears as a worthy distinct predictor of infertility in PCOS women. Therefore, Corin may be a substantial biomarker for PCOS.

METTL7A-mediated m6A modification of corin reverses bisphosphonates-impaired osteogenic differentiation of orofacial BMSCs

Bisphosphonate-related osteonecrosis of jaw (BRONJ) is characterized by impaired osteogenic differentiation of orofacial bone marrow stromal cells (BMSCs). Corin has recently been demonstrated to act as a key regulator in bone development and orthopedic disorders. However, the role of corin in BRONJ-related BMSCs dysfunction remains unclarified. A m6A epitranscriptomic microarray study from our group shows that the CORIN gene is significantly upregulated and m6A hypermethylated during orofacial BMSCs osteogenic differentiation. Corin knockdown inhibits BMSCs osteogenic differentiation, whereas corin overexpression or soluble corin (sCorin) exerts a promotion effect. Furthermore, corin expression is negatively regulated by bisphosphonates (BPs). Corin overexpression or sCorin reverses BPs-impaired BMSCs differentiation ability. Mechanistically, we find altered expression of phos-ERK in corin knockdown/overexpression BMSCs and BMSCs under sCorin stimulation. PD98059 (a selective ERK inhibitor) blocks the corin-mediated promotion effect. With regard to the high methylation level of corin during osteogenic differentiation, we apply a non-selective m6A methylase inhibitor, Cycloleucine, which also blocks the corin-mediated promotion effect. Furthermore, we demonstrate that METTL7A modulates corin m6A modification and reverses BPs-impaired BMSCs function, indicating that METTL7A regulates corin expression and thus contributes to orofacial BMSCs differentiation ability. To conclude, our study reveals that corin reverses BPs-induced BMSCs dysfunction, and METTL7A-mediated corin m6A modification underlies corin promotion of osteogenic differentiation via the ERK pathway. We hope this brings new insights into future clinical treatments for BRONJ.

Corin is a key regulator of endochondral ossification and bone development via modulation of vascular endothelial growth factor A expression

Corin has been studied extensively within the vascular system and is known to regulate blood pressure. We have shown that corin is one of the most highly upregulated genes during osteogenic differentiation of human adipose-derived stem cells (hASCs). This study tested the hypothesis that, through modulation of angiogenic signalling pathways, corin is a critical regulator of osteogenic differentiation and endochondral ossification. In vitro, corin expression in hASC was suppressed via siRNA knockdown and vascular endothelial growth factor A (VEGF-A) expression was quantified via reverse transcription polymerase chain reaction. In vivo, a murine corin knockout model (female, 10 weeks) was used to determine the effect of corin deficiency on long bone development. Wild-type and corin knockout long bones were compared via haematoxylin and eosin staining to assess tissue characteristics and cellular organization, three-point bending to assess mechanical characteristics, and immunohistochemistry to visualize VEGF-A expression patterns. Corin knockdown significantly (p < 0.05) increased VEGF-A mRNA expression during osteogenic differentiation. In vivo, corin knockout reduced tibial growth plate thickness (p < 0.01) and severely diminished the hypertrophic region. Corin knockout femurs had significantly increased stiffness (p < 0.01) and maximum loads (p < 0.01) but reduced postyield deflections (p < 0.01). In corin knockout mice, VEGF-A expression was increased near the growth plate but was reduced throughout the tibial shaft and distal head of the tibiae. This is the first study to show that corin is a key regulator of bone development by modulation of VEGF-A expression. Further elucidation of this mechanism will aid in the development of optimized bone tissue engineering and regenerative medicine therapies.

Role of the protease corin in chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) have the potency to differentiate into chondrocytes, osteocytes and adipocytes. Corin is a cardiac protease that activates the natriuretic peptides, thereby regulating blood volume and pressure. In addition to the heart, corin gene upregulation was reported in bone marrow- and adipose tissue-derived MSCs that underwent osteogenic differentiation. To date, the biological significance of corin expression in MSC differentiation remains unknown. In this study we isolated and cultured human bone marrow-derived MSCs that were capable of undergoing chondrogenic, osteogenic and adipogenic lineage differentiation. By reverse transcription polymerase chain reaction (RT-PCR) and immunostaining, we found that corin expression was upregulated when these MSCs underwent chondrogenic, osteogenic and adipogenic differentiation. The upregulation of corin expression was most significant in the cells undergoing chondrogenic lineage differentiation. Silencing corin gene expression by small hairpin RNA in the MSCs inhibited chondrogenic, but not osteogenic and adipogenic, differentiation. These results suggest a novel function of corin in MSC differentiation and chondrocyte development.

Association between serum soluble corin and hyperglycaemia: a cross-sectional study among Chinese adults

OBJECTIVES

Decreased natriuretic peptides are risk factors for diabetes. As a physiological activator of natriuretic peptides, corin may play a role in glucose metabolism. Here, we aimed to test the hypothesis in a general population of China.

DESIGN

Cross-sectional study.

SETTING

A population study in Suzhou, China.

PARTICIPANTS

A total of 2498 participants aged above 30 years were included in the study.

OUTCOME MEASURES

The association between serum soluble corin and hyperglycaemia was examined in men and women, using non-conditional logistic regression models, respectively.

RESULTS

Serum soluble corin, in men and women, was significantly higher in participants with hyperglycaemia than in those without (all p<0.001). OR of hyperglycaemia positively and significantly increased with serum soluble corin quartiles, in men (p for trend <0.001) and in women (p for trend=0.050), even after multivariate adjustment. Participants with a serum soluble corin, in men (OR=1.66, 95% CI 1.24 to 2.23) and women (OR=1.27, 95% CI 1.00 to 1.61), over the median level, were more likely to have hyperglycaemia compared with the remaining participants, after controlling for confounding factors.

CONCLUSIONS

Hyperglycaemia was significantly and positively associated with increased serum soluble corin in men and women. Our findings suggest that serum soluble corin may be a risk factor or a biomarker of hyperglycaemia.

Corin is down-regulated and exerts cardioprotective action via activating pro-atrial natriuretic peptide pathway in diabetic cardiomyopathy

Background

Diabetic cardiomyopathy (DCM), a fatal cardiovascular complication of diabetes mellitus, often leads to progressive heart failure, however its pathogenesis remains unclear. Corin, a cardiac serine protease, is responsible for converting pro-atrial natriuretic peptide (pro-ANP) to biologically active atrial natriuretic peptide (ANP). It has been well established that corin deficiency is associated with the progression of hypertension, cardiac hypertrophy and heart failure. However, because the involvement of corin-mediated pro-ANP processing in DCM has not been clarified, this study aims to investigate the role of corin in the pathogenesis of DCM.

Methods

Diabetes mellitus was induced by a single intraperitoneal injection of streptozotocin (STZ 65 mg/kg) to Sprague–Dawley rats (180–220 g). DCM was confirmed by monitoring continuously transthoracic echocardiography every 4 weeks and hemodynamic measurements at 20 weeks. Myocardial disorder and fibrosis were detected by HE staining and Masson’s trichrome staining. The mRNA and protein levels of corin and ANP in rat hearts and cardiomyocytes were determined by quantitative real-time PCR, western blotting and immunohistochemical staining, respectively. H9c2 cardiomyoblasts proliferation was detected by MTT colorimetric assay and viable cell counting with trypan blue. The effect of Corin-siRNA H9c2 cardiomyoblasts on EA.hy926 cells migration was measured by the wound healing scratch assay.

Results

The corin and ANP expression in mRNA and protein levels was decreased in DCM rat hearts. Corin and ANP levels of neonatal rat cardiomyocytes and H9c2 cardiomyoblasts treated with high glucose were significantly lower than that of normal glucose treated. Precisely, corin and ANP levels decreased in DCM rats at 12, 16, 20 and 33 weeks; neonatal cardiomyocytes and H9c2 cardiomyoblasts treated with high glucose at 36, 48 and 60 h demonstrated significant reduction in corin and ANP levels. Corin-siRNA H9c2 cardiomyoblasts showed decreased proliferation. Culture supernatants of Corin-siRNA H9c2 cardiomyoblasts prevented endothelial cell line EA.hy926 migration in the wound healing scratch assay. Furthermore, iso-lectin expression in arteriole and capillary endothelium was down-regulated in DCM rats.

Conclusions

Our results indicate that corin plays an important role in cardioprotection by activating pro-atrial natriuretic peptide pathway in DCM. Corin deficiency leads to endothelial dysfunction and vascular remodeling.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0298-9) contains supplementary material, which is available to authorized users.

Increased serum soluble corin in dyslipidemia: A cross-sectional study

BACKGROUND

Natriuretic peptides have been associated with dyslipidemia. As a physiological activator of natriuretic peptides, corin might also be associated with dyslipidemia. However, this association has not yet been studied in Chinese populations.

METHODS

Serum soluble corin and blood lipid profiles were determined for 2496 participants aged above 30y. A logistic regression model was applied to evaluate the association between serum soluble corin and dyslipidemia.

RESULTS

Serum soluble corin was significantly increased in participants with dyslipidemia in both men (P<0.001) and women (P<0.001). After controlling for the confounding factors, OR of dyslipidemia positively increased with increasing levels of serum soluble corin in men (P for trend=0.011) and women (P for trend=0.043). Participants with a high corin level were more likely to have dyslipidemia than those with a low corin level in men (OR, 95% CI: 1.45, 1.07-1.97) and women (OR, 95% CI: 1.33, 1.04-1.70).

CONCLUSION

Serum soluble corin was significantly and positively associated with dyslipidemia. Our findings suggested that serum soluble corin may be a marker or risk factor for dyslipidemia.

Serum Soluble Corin is Decreased in Stroke

BACKGROUND AND PURPOSE

Soluble corin was decreased in coronary heart disease. Given the connections between cardiac dysfunction and stroke, circulating corin might be a candidate marker of stroke risk. However, the association between circulating corin and stroke has not yet been studied in humans. Here, we aimed to examine the association in patients wtith stroke and community-based healthy controls.

METHODS

Four hundred eighty-one patients with ischemic stroke, 116 patients with hemorrhagic stroke, and 2498 healthy controls were studied. Serum soluble corin and some conventional risk factors of stroke were examined. Because circulating corin was reported to be varied between men and women, the association between serum soluble corin and stroke was evaluated in men and women, respectively.

RESULTS

Patients with ischemic and hemorrhagic stroke had a significantly lower level of serum soluble corin than healthy controls in men and women (all P values, <0.05). In multivariate analysis, men in the lowest quartile of serum soluble corin were more likely to have ischemic (odds ratio [OR], 4.90; 95% confidence interval, 2.99-8.03) and hemorrhagic (OR, 17.57; 95% confidence interval, 4.85-63.71) stroke than men in the highest quartile. Women in the lowest quartile of serum soluble corin were also more likely to have ischemic (OR, 3.10; 95% confidence interval, 1.76-5.44) and hemorrhagic (OR, 8.54; 95% confidence interval, 2.35-31.02) stroke than women in the highest quartile. ORs of ischemic and hemorrhagic stroke were significantly increased with the decreasing levels of serum soluble corin in men and women (all P values for trend, <0.001).

CONCLUSIONS

Serum soluble corin was decreased in patients with stroke compared with healthy controls. Our findings raise the possibility that serum soluble corin may have a pathogenic role in stroke.

Association between serum soluble corin and obesity in Chinese adults: a cross-sectional study

OBJECTIVE

Corin has been suggested to be associated with obesity by cell- and animal-based studies. However, the association has not yet been studied in populations. Here, the aim was to explore the association in a general population of China.

METHODS

This was a cross-sectional study. Data on demographic information, lifestyle risk factors, and personal medical history were collected; body mass index, waist circumference, and blood pressures were measured; and serum corin, blood lipids, and blood glucose were determined in 2498 participants aged above 30 years.

RESULTS

Log-transformed corin correlated to body mass index (r = 0.197, P < 0.001) and waist circumference (r = 0.289, P < 0.001). In the risk factor-adjusted analysis, compared with participants in the lowest quartile of serum corin, participants in the 4th quartile had significantly increased risk of prevalent overweight or obesity (OR = 2.26, 95% CI: 1.67-3.04) and central obesity (OR = 1.74, 95% CI: 1.30-2.34). ORs of overweight or obesity and central obesity positively and significantly increased with serum corin levels (P for trend < 0.001).

CONCLUSIONS

Serum soluble corin was significantly and positively associated with obesity. Our findings suggested that serum soluble corin may be a marker or risk factor for obesity.