Increases in plasma corin levels following experimental myocardial infarction reflect the severity of ischemic injury

Corin in cardiovascular diseases and stroke

Corin is a type II transmembrane serine protease highly expressed in the heart. It plays a critical role in regulating fluid balance and improving cardiac function by converting pro-atrial natriuretic peptide into mature atrial natriuretic peptide. CORIN variants have been identified in patients with hypertension, heart failure, atrial fibrillation, and stroke. In vivo and in vitro, corin deficiency increases blood pressure and impairs cardiac function. Circulating soluble corin appears to have potential as a stable and specific biomarker for the risk prediction and prognostic assessment of cardiovascular diseases (CVDs) and stroke. In this review, we summarize the current knowledge on corin physiology and circulating corin and discuss cardiac corin expression and function in CVDs. In the future, corin-related therapeutic approaches to increase corin activity and raise corin levels may offer new opportunities to treat CVDs.

Corin deficiency impairs cardiac function in mouse models of heart failure

Introduction

Corin is a protease in the natriuretic peptide system. Deleterious CORIN variants are associated with hypertension and heart disease. It remains unclear if and to what extent corin deficiency may contribute to heart failure (HF).

Methods

Corin knockout (KO) mice were used as a model. Cardiac function was assessed by echocardiography and tissue analysis in Corin KO mice at different ages or subjected to transverse aortic constriction (TAC), which increased pressure overload. Heart and lung tissues were analyzed for cardiac hypertrophy and lung edema using wheat germ agglutinin, Sirius red, Masson's trichrome, and Prussian blue staining. Recombinant corin was tested for its effect on cardiac function in the TAC-operated Corin KO mice. Selected gene expression in the heart was examined by RT-PCR. ELISA was used to analyze factors in plasma.

Results

Corin KO mice had progressive cardiac dysfunction with cardiac hypertrophy and fibrosis after 9 months of age, likely due to chronic hypertension. When Corin KO mice were subjected to TAC at 10-12 weeks of age, cardiac function decreased more rapidly than in similarly treated wild-type mice. When the TAC-operated Corin KO mice were treated with recombinant corin protein, cardiac dysfunction, hypertrophy, and fibrosis were ameliorated. The corin treatment also decreased the gene expression associated with cardiac hypertrophy and fibrosis, increased plasma cGMP levels, lowered plasma levels of N-terminal pro-atrial natriuretic peptide, angiotensin II, and aldosterone, and lessened lung edema in the Corin KO mice subjected to TAC.

Conclusion

Corin deficiency impairs cardiac function and exacerbates HF development in mice. Corin protein may be used to reduce cardiac hypertrophy and fibrosis, suppress the renin-angiotensin-aldosterone system, and improve cardiac function in HF.

Corin is regulated by circ-0012397/miR-200a-3p and inhibits the oxygen-glucose deprivation-induced apoptosis of SHSY5Y neuroblastoma cells

Background

As a type II transmembrane serine protease, corin plays a role in several important physiological and pathological processes. We conducted a bioinformatics analysis to explore the roles of both corin and circ-0012397/miR-200a-3p in ischemic stroke.

Methods

We established an in vitro model using oxygen-glucose deprivation (OGD)-induced SHSY5Y cells. The proliferation and apoptosis of SHSY5Y cells was determined using Cell Counting Kit-8 (CCK-8) and flow cytometry/Hoechst 33258 staining, respectively. The RNA and protein level was tested using Real Time Quantitative Polymerase Chain Reaction (RT-qPCR) and western blot, respectively. The regulatory relationship of corin and circ-0012397/miR-200a-3p were detected by dual-luciferase reporter assays.

Results

We found that OGD downregulated the expression of corin in a time-dependent manner; this change was inversely proportional to the rate of apoptosis of the SHSY5Y cells. Further, high expression levels of corin enhanced the proliferation of SHSY5Y cells and inhibited the apoptosis of SHSY5Y cells by downregulating the expression of cleaved caspase-3, B-cell lymphoma 2 (BCL-2)-associated death promoter, extracellular-regulated protein kinase (ERK), and protein 38 (p38), and upregulated the expression of Bcl-2. Further, the dual-luciferase reporter assays and RT-qPCR showed that corin expression was regulated by circ-0012397/miR-200a-3p. Corin expression was affected by changes in circ-0012397 and miR-200a-3p expression, which were overexpressed or inhibited. Further, corin exerted different regulatory effects on apoptosis signaling-related proteins, including AD Bcl-2, cleaved caspase-3, ERK, and p38, under different expression levels of circ-0012397 and miR-200a-3p.

Conclusions

Corin promotes the cell proliferation and inhibits OGD-induced apoptosis of SHSY5Y cells, and that its expression is regulated by circ-0012397/miR-200a-3p. Thus, corin may be a potential target for ischemic stroke patients.

Edema formation in congestive heart failure and the underlying mechanisms

Congestive heart failure (HF) is a complex disease state characterized by impaired ventricular function and insufficient peripheral blood supply. The resultant reduced blood flow characterizing HF promotes activation of neurohormonal systems which leads to fluid retention, often exhibited as pulmonary congestion, peripheral edema, dyspnea, and fatigue. Despite intensive research, the exact mechanisms underlying edema formation in HF are poorly characterized. However, the unique relationship between the heart and the kidneys plays a central role in this phenomenon. Specifically, the interplay between the heart and the kidneys in HF involves multiple interdependent mechanisms, including hemodynamic alterations resulting in insufficient peripheral and renal perfusion which can lead to renal tubule hypoxia. Furthermore, HF is characterized by activation of neurohormonal factors including renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), endothelin-1 (ET-1), and anti-diuretic hormone (ADH) due to reduced cardiac output (CO) and renal perfusion. Persistent activation of these systems results in deleterious effects on both the kidneys and the heart, including sodium and water retention, vasoconstriction, increased central venous pressure (CVP), which is associated with renal venous hypertension/congestion along with increased intra-abdominal pressure (IAP). The latter was shown to reduce renal blood flow (RBF), leading to a decline in the glomerular filtration rate (GFR). Besides the activation of the above-mentioned vasoconstrictor/anti-natriuretic neurohormonal systems, HF is associated with exceptionally elevated levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). However, the supremacy of the deleterious neurohormonal systems over the beneficial natriuretic peptides (NP) in HF is evident by persistent sodium and water retention and cardiac remodeling. Many mechanisms have been suggested to explain this phenomenon which seems to be multifactorial and play a major role in the development of renal hyporesponsiveness to NPs and cardiac remodeling. This review focuses on the mechanisms underlying the development of edema in HF with reduced ejection fraction and refers to the therapeutic maneuvers applied today to overcome abnormal salt/water balance characterizing HF.

Evaluation of CORIN in patients with heart failure: A systematic review and meta-analysis

Objectives: We aim to evaluate the association between CORIN and heart failure.

Methods: This study used PubMed, EMBASE, Cochrane database, and China National Knowledge Database (CNKI) to search for CORIN-related full-text articles with heart failure patients. We drew forest plots, performed sensitivity and bias analyses based on the included data. Next, we used Review Manager 5.2 software to assess the heterogeneity among selected articles.

Results: Our meta-analysis results showed there was significant relationship between CORIN and heart failure (HF). There was significant difference of CORIN between heart failure group and control group (MD = −293.88, 95% confidence interval [-380.26, −207.49], p < .00001; heterogeneity p < .0001, I2= 97%) and there was significant difference in CORIN between ischemic group and non-ischemic group (MD = 88.79, 95% confidence interval [70.46107.12], heterogeneity p < .000, p = 0.94, l2= 0%). In subgroup analysis, there were significant differences in three different HF levels. Limited publication bias was observed, and this study was robust.

Conclusion: In short, the results showed that CORIN was closely related with heart failure and might be helpful in the diagnosis of heart failure.

A Low-Sodium Diet Boosts Ang (1-7) Production and NO-cGMP Bioavailability to Reduce Edema and Enhance Survival in Experimental Heart Failure

Sodium restriction is often recommended in heart failure (HF) to block symptomatic edema, despite limited evidence for benefit. However, a low-sodium diet (LSD) activates the classical renin-angiotensin-aldosterone system (RAAS), which may adversely affect HF progression and mortality in patients with dilated cardiomyopathy (DCM). We performed a randomized, blinded pre-clinical trial to compare the effects of a normal (human-equivalent) sodium diet and a LSD on HF progression in a normotensive model of DCM in mice that has translational relevance to human HF. The LSD reduced HF progression by suppressing the development of pleural effusions (p < 0.01), blocking pathological increases in systemic extracellular water (p < 0.001) and prolonging median survival (15%, p < 0.01). The LSD activated the classical RAAS by increasing plasma renin activity, angiotensin II and aldosterone levels. However, the LSD also significantly up-elevated the counter-regulatory RAAS by boosting plasma angiotensin converting enzyme 2 (ACE2) and angiotensin (1-7) levels, promoting nitric oxide bioavailability and stimulating 3'-5'-cyclic guanosine monophosphate (cGMP) production. Plasma HF biomarkers associated with poor outcomes, such as B-type natriuretic peptide and neprilysin were decreased by a LSD. Cardiac systolic function, blood pressure and renal function were not affected. Although a LSD activates the classical RAAS system, we conclude that the LSD delayed HF progression and mortality in experimental DCM, in part through protective stimulation of the counter-regulatory RAAS to increase plasma ACE2 and angiotensin (1-7) levels, nitric oxide bioavailability and cGMP production.

Corin Overexpression Reduces Myocardial Infarct Size and Modulates Cardiomyocyte Apoptotic Cell Death

Altered expression of corin, a cardiac transmembrane serine protease, has been linked to dilated and ischemic cardiomyopathy. However, the potential role of corin in myocardial infarction (MI) is lacking. This study examined the outcomes of MI in wild-type vs. cardiac-specific overexpressed corin transgenic (Corin-Tg) mice during pre-MI, early phase (3, 24, 72 h), and late phase (1, 4 weeks) post-MI. Corin overexpression significantly reduced cardiac cell apoptosis (p < 0.001), infarct size (p < 0.001), and inhibited cleavage of procaspases 3, 9, and 8 (p < 0.05 to p < 0.01), as well as altered the expression of Bcl2 family proteins, Bcl-xl, Bcl2 and Bak (p < 0.05 to p < 0.001) at 24 h post-MI. Overexpressed cardiac corin also significantly modulated heart function (ejection fraction, p < 0.0001), lung congestion (lung weight to body weight ratio, p < 0.0001), and systemic extracellular water (edema, p < 0.05) during late phase post-MI. Overall, cardiac corin overexpression significantly reduced apoptosis, infarct size, and modulated cardiac expression of key members of the apoptotic pathway in early phase post-MI; and led to significant improvement in heart function and reduced congestion in late phase post-MI. These findings suggest that corin may be a useful target to protect the heart from ischemic injury and subsequent post-infarction remodeling.