Reprint of: Catestatin: a multifunctional peptide from chromogranin A

Plasma catestatin levels are related to metabolic parameters in patients with essential hypertension and type 2 diabetes mellitus

Catestatin (CST) is a pleiotropic peptide with cardioprotective and metabolic effects. CST is involved in the pathogenesis of both arterial hypertension (AH) and type 2 diabetes mellitus (T2DM), which are the risk factors of cardiovascular diseases. In this study, we aimed to investigate the plasma CST levels in hypertensive patients, especially with T2DM, as well as compare those with healthy volunteers, and explore the relationship between CST levels and clinical, anthropometric and laboratory parameters. 106 Hypertensive patients, 55 of which had comorbidity T2DM, and 30 healthy volunteers were enrolled in the study. All subjects underwent clinical examination, including vital signs and anthropometric data assessment, medical history interview, and blood sample collection. Plasma CST levels were measured by an enzyme-linked immunosorbent assay (ELISA), using a commercial diagnostic kit. The plasma CST levels were significantly lower in hypertensive patients (N = 106) compared with healthy subjects (N = 30) (5.02 ± 1.09 vs. 6.64 ± 0.72; p < 0.001). Furthermore, hypertensive patients with T2DM (N = 55) have significantly reduced CST levels in comparison with those without T2DM (N = 51) (4.47 ± 1.16 vs. 5.61 ± 0.61; p < 0.001). CST significantly correlated with anthropometric characteristics, in particular, weight (r =  - 0.344; p < 0.001), BMI (r =  - 0.42; p < 0.001), neck (r =  - 0.358; p < 0.001), waist (r =  - 0.487; p < 0.001), hip (r =  - 0.312; p < 0.001), wrist circumferences (r =  - 0.264; p = 0.002), and waist-to-hip ratio (r =  - 0.395; p < 0.001). Due to its antihypertensive effect, CST has significant associations with systolic BP (r =  - 0.475; p < 0.001) and duration of AH (r =  - 0.26; p = 0.007). CST also has an inverse relationship with insulin (r =  - 0.382; p < 0.001), glucose (r =  - 0.45; p < 0.001), index HOMA-IR (r =  - 0.481; p < 0.001) and HbA1c (r =  - 0.525; p < 0.001), that indicate its involvement in T2DM development. Besides, CST has significant correlations with uric acid levels (r =  - 0.412; p < 0.001) as well as lipid parameters, especially HDL-C (r = 0.480; p < 0.001), VLDL-C (r =  - 0.238; p = 0.005), TG (r =  - 0.4; p < 0.001), non-HDL-C/HDL-C (r =  - 0.499; p < 0.001). Multiple linear regression analysis indicated BMI (β =  - 0.22; p = 0.007), AH duration (β =  - 0.25; p = 0.008), HbA1c (β =  - 0.43; p = 0.019) and HDL-C levels (β = 0.27; p = 0.001) as independent predictors of CST levels. The hypertensive patients have significantly decreased CST levels that are even more reduced in the presence of comorbid T2DM. The established correlations with anthropometric and laboratory parameters indicate not only antihypertensive but also metabolic effects of CST. Our results suggest the probable role of CST in the pathophysiology of cardiometabolic diseases and the development of cardiovascular complications.

Differential Antihypertensive Effects of Oral Doses of Acetylcholine between Spontaneously Hypertensive Rats and Normotensive Rats

Acetylcholine (ACh) is a novel antihypertensive food component. Here, we demonstrate the differential effects of oral ACh on high and normal blood pressure in rats. Spontaneously hypertensive rats (SHRs) and Wistar–Kyoto (WKY) rats were administered ACh orally. The blood pressure and heart rate of SHRs were significantly lowered with ACh doses of 10⁻⁵ and 10⁻³ mol/kg body weight (b.w.), and the urinary catecholamine levels were significantly decreased with 10⁻³ mol/kg b.w. In contrast, oral ACh administration had no effect on WKY rats. This difference was likely caused by differences in sympathetic nervous activity and the baroreflex between strains. Comparison of gene sequences between the two strains revealed Chga mutations, suggesting that changes in the expression of chromogranin A might be involved in the baroreflex in SHRs. Oral ACh had an antihypertensive effect under hypertension but not normotension, indicating that this may be used safely to prevent hypertension.

Decreased circulating catestatin levels are associated with coronary artery disease: The emerging anti-inflammatory role

BACKGROUND AND AIMS

The neuropeptide catestatin (CST) is an endogenous nicotinic cholinergic antagonist that acts as pleiotropic cardiac protective hormone. This study investigated the association between CST and coronary artery disease (CAD) and the underlying mechanisms.

METHODS AND RESULTS

The serum concentration of CST among 224 CAD patients and 204 healthy controls was compared, and its association with atherosclerosis severity in 921 CAD patients was further analyzed. Compared to healthy subjects, serum CST concentration was lower in patients with CAD [1.14 (1.05-1.24) ng/mL vs. 2.15 (1.92-2.39) ng/mL, p < 0.001] and was inversely correlated with disease severity (r = -0.208, p < 0.001). In cultured endothelial cells, CST suppressed TNF-α-elicited expression of inflammatory cytokines and adhesion molecules by activating angiotensin-converting enzyme-2 (ACE2). Administration of CST reduced leukocyte-endothelium interactions in vitro and in vivo, and attenuated the development of atherosclerotic in ApoE^-/- mice fed a high-fat diet. These protective effects by CST were blocked by an ACE2 inhibitor.

CONCLUSIONS

Serum CST concentration is lower in CAD patients and is inversely associated with the severity of atherosclerosis. CST acts as a novel anti-atherogenic peptide that inhibits inflammatory response and EC-leukocyte interactions via an ACE2-dependent mechanism.

Correlation of plasma catestatin level and the prognosis of patients with acute myocardial infarction

Catestatin is a peptide which is a potent inhibitor of catecholamine secretion and played essential functions in the cardiovascular system. Previous research found that dramatic changes of catestatin were associated with hemodynamics in acute myocardial infarction (AMI) during the first week after the AMI symptoms onset, but whether catestatin is also involved in the pathophysiological progression after AMI and then a predictor for outcomes is not clear. The aim of this study is to determine the correlation of plasma catestatin levels at different time points and the prognosis of AMI. 100 participants recruited were all patients with AMI, all of who received successful primary percutaneous coronary intervention (PCI) within 12h from the AMI symptom onset in our center; the concentrations of plasma catestatin were evaluated from blood samples of those 100 participants. Subsequent 65 months' follow-up was performed after discharging to evaluate cardiac adverse events and the association between catestatin levels and prognosis of AMI was examined. We confirmed the dramatic change of catestatin concentrations in the first week of AMI, and the levels of catestatin on D3 were much higher in adverse events group than those in non-adverse events group (p<0.0001), but the ratio of D7/D3 was significantly lower. In addition, the Kaplan-Meier analysis showed that the groups in which the levels on D3 were higher (p<0.0001) and the ratios of D7/D3 were lower (p<0.0001), patients trended to be more susceptive to adverse events after AMI. Furthermore, according to the analysis, we surmised catestatin level on D3 as an appropriate predictor for outcomes in patients with AMI with good specificity as well as sensitivity. All of the evidence confirmed that catestatin plays an important role in the progress of AMI, and may act as a promising target for prognostic prediction.

The important role of catestatin in cardiac remodeling

Catestatin (CST) was first discovered as a potent non-competitive and reversible inhibitor of catecholamine secretion. Recent reports on plasma CST level in heart diseases suggested a cardioprotective role for this peptide. Given that cardiac remodeling is the dominant pathologic process in cardiac dysfunction, we propose that CST participates in the regulation of concern pathways and contributes to the inhibition of cardiac remodeling. In this minireview, the potential mechanism of cardiac remodeling involving CST will be discussed from three aspects: hypertrophy, fibrosis, and apoptosis.

The surging role of Chromogranin A in cardiovascular homeostasis

Together with Chromogranin B and Secretogranins, Chromogranin A (CGA) is stored in secretory (chromaffin) granules of the diffuse neuroendocrine system and released with noradrenalin and adrenalin. Co-stored within the granule together with neuropeptideY, cardiac natriuretic peptide hormones, several prohormones and their proteolytic enzymes, CGA is a multifunctional protein and a major marker of the sympatho-adrenal neuroendocrine activity. Due to its partial processing to several biologically active peptides, CGA appears an important pro-hormone implicated in relevant modulatory actions on endocrine, cardiovascular, metabolic, and immune systems through both direct and indirect sympatho-adrenergic interactions. As a part of this scenario, we here illustrate the emerging role exerted by the full-length CGA and its three derived fragments, i.e., Vasostatin 1, catestatin and serpinin, in the control of circulatory homeostasis with particular emphasis on their cardio-vascular actions under both physiological and physio-pathological conditions. The Vasostatin 1- and catestatin-induced cardiodepressive influences are achieved through anti-beta-adrenergic-NO-cGMP signaling, while serpinin acts like beta1-adrenergic agonist through AD-cAMP-independent NO signaling. On the whole, these actions contribute to widen our knowledge regarding the sympatho-chromaffin control of the cardiovascular system and its highly integrated “whip-brake” networks.

Cardiac electrical activity in a genomically "humanized" chromogranin a monogenic mouse model with hyperadrenergic hypertension

The prohormone chromogranin A (CHGA) is ubiquitously found in vesicles of adrenal chromaffin cells and adrenergic neurons, and it is processed to the hypotensive hormone peptide catestatin (CST). Both CHGA and CST regulate blood pressure and cardiac function. This study addresses their role in cardiac electrical activity. We have generated two genomically "humanized" transgenic mouse strains (Tg31CHGA+/+; Chga-/- (HumCHGA31) and Tg19CHGA+/+; Chga-/- (HumCHGA19)) with varied CHGA expression and the ability to rescue the Chga-/- phenotype (hypertensive, hyperadrenergic with dilated cardiomyopathy). The normotensive HumCHGA31 mice express CHGA at levels comparable to wild-type. In contrast, the hypertensive HumCHGA19 mice have low levels of CHGA. EKG recordings revealed that the QT interval, R-amplitude, and QRS time-voltage integral are markedly longer in HumCHGA19 compared to wild-type and HumCHGA31 mice. These differences are accompanied by increased heart rate and QT variability, indicating that ventricular assault happens in a status of low levels of circulating CST.

Functional genetic variants of the catecholamine-release-inhibitory peptide catestatin in an Indian population: allele-specific effects on metabolic traits

Catestatin (CST), a chromogranin A (CHGA)-derived peptide, is a potent inhibitor of catecholamine release from adrenal chromaffin cells and postganglionic sympathetic axons. We re-sequenced the CST region of CHGA in an Indian population (n = 1010) and detected two amino acid substitution variants: G364S and G367V. Synthesized CST variant peptides (viz. CST-Ser-364 and CST-Val-367) were significantly less potent than the wild type peptide (CST-WT) to inhibit nicotine-stimulated catecholamine secretion from PC12 cells. Consistently, the rank-order of blockade of nicotinic acetylcholine receptor (nAChR)-stimulated inward current and intracellular Ca(2+) rise by these peptides in PC12 cells was: CST-WT > CST-Ser-364 > CST-Val-367. Structural analysis by CD spectroscopy coupled with molecular dynamics simulations revealed the following order of α-helical content: CST-WT > CST-Ser-364 > CST-Val-367; docking of CST peptides onto a major human nAChR subtype and molecular dynamics simulations also predicted the above rank order for their binding affinity with nAChR and the extent of occlusion of the receptor pore, providing a mechanistic basis for differential potencies. The G364S polymorphism was in strong linkage disequilibrium with several common CHGA genetic variations. Interestingly, the Ser-364 allele (detected in ∼15% subjects) was strongly associated with profound reduction (up to ∼2.1-fold) in plasma norepinephrine/epinephrine levels consistent with the diminished nAChR desensitization-blocking effect of CST-Ser-364 as compared with CST-WT. Additionally, the Ser-364 allele showed strong associations with elevated levels of plasma triglyceride and glucose levels. In conclusion, a common CHGA variant in an Indian population influences several biochemical parameters relevant to cardiovascular/metabolic disorders.

The extended granin family: structure, function, and biomedical implications

The chromogranins (chromogranin A and chromogranin B), secretogranins (secretogranin II and secretogranin III), and additional related proteins (7B2, NESP55, proSAAS, and VGF) that together comprise the granin family subserve essential roles in the regulated secretory pathway that is responsible for controlled delivery of peptides, hormones, neurotransmitters, and growth factors. Here we review the structure and function of granins and granin-derived peptides and expansive new genetic evidence, including recent single-nucleotide polymorphism mapping, genomic sequence comparisons, and analysis of transgenic and knockout mice, which together support an important and evolutionarily conserved role for these proteins in large dense-core vesicle biogenesis and regulated secretion. Recent data further indicate that their processed peptides function prominently in metabolic and glucose homeostasis, emotional behavior, pain pathways, and blood pressure modulation, suggesting future utility of granins and granin-derived peptides as novel disease biomarkers.

Catestatin is useful in detecting patients with stage B heart failure

Screening patients with stage B heart failure(HF) may be one strategy for reducing human morbidity. To describe catestatin levels in different stages of HF and evaluate the diagnostic utility of catestatin for detecting stage B HF, we included 300 patients. Catestatin, BNP testing and echocardiogram were performed. Our studies showed catestatin decreased gradually from stage A to C. There was significant difference between stage A and B. Cutoff value for detecting stage B HF was 19.73 ng/ml for catestatin with 90% sensitivity and 50.9% specificity. These results may have implications in the new method to detect patients with stage B HF.

Cysteine Cathepsins in the secretory vesicle produce active peptides: Cathepsin L generates peptide neurotransmitters and cathepsin B produces beta-amyloid of Alzheimer's disease

Recent new findings indicate significant biological roles of cysteine cathepsin proteases in secretory vesicles for production of biologically active peptides. Notably, cathepsin L in secretory vesicles functions as a key protease for proteolytic processing of proneuropeptides (and prohormones) into active neuropeptides that are released to mediate cell-cell communication in the nervous system for neurotransmission. Moreover, cathepsin B in secretory vesicles has been recently identified as a β-secretase for production of neurotoxic β- amyloid (Aβ) peptides that accumulate in Alzheimer's disease (AD), participating as a notable factor in the severe memory loss in AD. These secretory vesicle functions of cathepsins L and B for production of biologically active peptides contrast with the well-known role of cathepsin proteases in lysosomes for the degradation of proteins to result in their inactivation. The unique secretory vesicle proteome indicates proteins of distinct functional categories that provide the intravesicular environment for support of cysteine cathepsin functions. Features of the secretory vesicle protein systems insure optimized intravesicular conditions that support the proteolytic activity of cathepsins. These new findings of recently discovered biological roles of cathepsins L and B indicate their significance in human health and disease. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.

The novel role of cathepsin L for neuropeptide production illustrated by research strategies in chemical biology with protease gene knockout and expression

Neuropeptides are essential for cell-cell communication in the nervous and endocrine systems. Production of active neuropeptides requires proteolytic processing of proneuropeptide precursors in secretory vesicles that produce, store, and release neuropeptides that regulate physiological functions. This review describes research strategies utilizing chemical biology combined with protease gene knockout and expression to demonstrate the key role of cathepsin L for production of neuropeptides in secretory vesicles. Cathepsin L was discovered using activity-based probes and mass spectrometry to identify proenkephalin cleaving activity as cathepsin L. Significantly, in vivo protease gene knockout and expression approaches illustrate the key role of cathepsin L for neuropeptide production. Notably, cathepsin L is colocalized with neuropeptide secretory vesicles, the major site of proteolytic processing of proneuropeptides to generate active neuropeptides. Cathepsin L participates in producing opioid neuropeptides consisting of enkephalin, β-endorphin, and dynorphin, as well as in generating the POMC-derived peptide hormones ACTH and α-MSH. In addition, NPY, CCK, and catestatin neuropeptides utilize cathepsin L for their biosynthesis. The role of cathepsin L for neuropeptide production indicates its unique biological role in secretory vesicles, which contrasts with its role in lysosomes for protein degradation. Interesting evaluations of protease gene knockout studies in mice that lack cathepsin L compared to the PC1/3 and PC2 (PC, prohormone convertase) indicate the significant role of cathepsin L in neuropeptide production. Thus, dual cathepsin L and prohormone convertase protease pathways participate in neuropeptide production. These recent new findings indicate cathepsin L as a novel 'proprotein convertase' for production of neuropeptides that mediate cell-cell communication in health and disease.