Secretoneurin is a secretogranin-2 derived hormonal peptide in vertebrate neuroendocrine systems

Prognostic value of plasma secretoneurin concentration in patients with heart failure with reduced ejection fraction in one-year follow-up

BACKGROUND

This is the first study to examine the clinical utility of measuring plasma secretoneurin (SN) levels in patients with heart failure with reduced ejection fraction (HFrEF), as a predictor of unplanned hospitalization, and all-cause mortality independently, and as a composite endpoint at one-year follow-up.

METHODS

The study group includes 124 caucasian patients in New York Heart Association (NYHA) classes II to IV. Plasma SN concentrations were statistically analyzed in relation to sex, age, BMI, etiology of HFrEF, pharmacotherapy, clinical, laboratory and echocardiographic parameters. Samples were collected within 24 h of admission to the hospital.

KEY RESULTS

In the 12-month follow-up, high SN levels were noted for all three endpoints.

CONCLUSIONS

SN positively correlates with HF severity measured by NYHA classes and proves to be a useful prognostic parameter in predicting unplanned hospitalizations and all-cause mortality among patients with HFrEF. Patients with high SN levels may benefit from systematic follow-up and may be candidates for more aggressive treatment.

Long-term exposure to aryl hydrocarbon receptor agonist neburon induces reproductive toxicity in male zebrafish (Danio rerio)

Neburon is a phenylurea herbicide that is widely used worldwide, but its toxicity is poorly studied. In our previous study, we found that neburon has strong aryl hydrocarbon receptor (AhR) agonist activity, but whether it causes reproductive toxicity is not clear. In the present study, zebrafish were conducted as a model organism to evaluate whether environmental concentrations of neburon (0.1, 1 and 10 µg/L) induce reproductive disorder in males. After exposure to neburon for 150 days from embryo to adult, that the average spawning egg number in high concentration group was 106.40, which was significantly lower than 193.00 in control group. This result was mainly due to the abnormal male reproductive behavior caused by abnormal transcription of genes associated with reproductive behavior in the brain, such as secretogranin-2a. The proportions of spermatozoa in the medium and high concentration groups were 82.40% and 83.84%, respectively, which were significantly lower than 89.45% in control group. This result was mainly caused by hormonal disturbances and an increased proportion of apoptotic cells. The hormonal disruption was due to the significant changes in the transcription levels of key genes in the hypothalamus-pituitary-gonadal axis following neburon treatment. Neburon treatment also significantly activated the AhR signaling pathway, causing oxidative stress damage and eventually leading to a significant increase in apoptosis in the exposed group. Together, these data filled the currently more vacant profile of neburon toxicity and might provide information to assess the ecotoxicity of neburon on male reproduction at environmentally relevant concentrations.

In Search of a Target Gene for a Desirable Phenotype in Aquaculture: Genome Editing of Cyprinidae and Salmonidae Species

Aquaculture supplies the world food market with a significant amount of valuable protein. Highly productive aquaculture fishes can be derived by utilizing genome-editing methods, and the main problem is to choose a target gene to obtain the desirable phenotype. This paper presents a review of the studies of genome editing for genes controlling body development, growth, pigmentation and sex determination in five key aquaculture Salmonidae and Cyprinidae species, such as rainbow trout (Onchorhynchus mykiss), Atlantic salmon (Salmo salar), common carp (Cyprinus carpio), goldfish (Carassius auratus), Gibel carp (Carassius gibelio) and the model fish zebrafish (Danio rerio). Among the genes studied, the most applicable for aquaculture are mstnba, pomc, and acvr2, the knockout of which leads to enhanced muscle growth; runx2b, mutants of which do not form bones in myoseptae; lepr, whose lack of function makes fish fast-growing; fads2, Δ6abc/5Mt, and Δ6bcMt, affecting the composition of fatty acids in fish meat; dnd mettl3, and wnt4a, mutants of which are sterile; and disease-susceptibility genes prmt7, gab3, gcJAM-A, and cxcr3.2. Schemes for obtaining common carp populations consisting of only large females are promising for use in aquaculture. The immobilized and uncolored zebrafish line is of interest for laboratory use.

Simultaneous extraction and detection of peptides, steroids, and proteins in small tissue samples

The detection and quantification of hormones are important to assess the reproductive and stress status of experimental models and for the diagnosis of diseases in human and veterinary clinics. Traditionally, steroid, peptide, and protein hormones are analyzed in individual experiments using different extraction methodologies. With the new advancement on HPLC sorbents, the simultaneous measurement of hormones from different categories becomes possible. In this study, we present a novel sample processing strategy for the simultaneous extraction and detection of peptides, steroids, and proteins using high-resolution liquid chromatography tandem mass spectrometry. We demonstrate the sensitivity of our method for small tissues by acquiring data from brain, pituitary gland, and gonads of single zebrafish samples. This approach promises to shed light on the hormonal pathways and their interrelationships, providing knowledge on the integration of hormone systems.

Function of secretoneurin in regulating the expression of reproduction-related genes in ovoviviparous black rockfish (Sebastes schlegelii)

Secretoneurin (SN), a conserved peptide derived from secretogranin-2 (scg2), also known as secretogranin II or chromogranin C, plays an important role in regulating gonadotropin in the pituitary, which affects the reproductive system. This study aimed to clarify the mode of action of scg2 in regulating gonad development and maturation and the expression of mating behavior-related genes. Two scg2 cDNAs were cloned from the ovoviviparity teleost black rockfish (Sebastes schlegelii). In situ hybridization detected positive scg2 mRNA signals in the telencephalon and hypothalamus, where sgnrh and kisspeptin neurons were reported to be located and potentially regulated by scg2. In vivo, intracerebral ventricular injections of synthetic black rockfish SNa affected brain cgnrh, sgnrh, kisspeptin1, pituitary lh and fsh and gonad steroidogenesis-related gene expression levels with sex dimorphism. In vitro, a similar effect was found in primary cultured brain and pituitary cells. Thus, SN could contribute to the regulation of gonadal development, as well as reproductive behaviors, including mating and parturition.

Bone marrow-derived mesenchymal stem cells accelerate angiogenesis in pregnant experimentally induced deep venous thrombosis rat model via up-regulation of pro-angiogenic secretogranin II

The present study investigated whether bone marrow-derived mesenchymal stem cells (BMMSCs) facilitate angiogenesis and improve outcomes of pregnancy with obstetric deep venous thrombosis (DVT) and explored the underlying mechanism. A pregnant DVT rat model was established using a "stenosis" method on the lower segment of the inferior vena cava (IVC). The extent of vascularization in thrombosed IVC was examined by immunohistochemistry. In addition, the effect of BMMSCs on DVT pregnancy outcomes was evaluated. We also characterized the effect of BMMSC-derived conditioned medium (BM-CM) on the impaired human umbilical vein endothelial cells (HUVECs). Thereafter, transcriptome sequencing was employed to identify the differentially expressed genes in thrombosed IVC tissues of DVT and DVT plus BMMSCs (thrice) groups. Lastly, the candidate gene's role in the promotion of angiogenesis was demonstrated in vitro and in vivo. The DVT model was successfully established using IVC stenosis. The injection of three consecutive BMMSC doses into pregnant SD rats with DVT was demonstrated to be the most effective treatment, which significantly reduced the length and weight of the thrombus, induced the highest level of angiogenesis, and ameliorated the embryo absorption rate. In vitro, BM-CM efficiently increased the abilities of impaired endothelial cells to proliferate, migrate, invade, and form vessel-like tubes, while inhibiting their apoptosis. Transcriptome sequencing revealed that BMMSCs induced a prominent upregulation of a variety of pro-angiogenic genes, including secretogranin II (SCG2). When SCG2 expression was knocked down by lentivirus, the BMMSCs' and BM-CM-induced pro-angiogenic effects on pregnant DVT rats and HUVECs were markedly attenuated. In conclusion, the study results suggest that BMMSCs enhance angiogenesis via up-regulation of SCG2, providing an effective alternative regenerative agent and novel target for the therapy of obstetric DVT.

Molecular Mechanisms of Tebuconazole Affecting the Social Behavior and Reproduction of Zebrafish

The aim of this study was to explore the underlying mechanism of adverse effects caused by tebuconazole (TEB) on the reproduction of aquatic organisms In the present study, in order to explore the effects of TEB on reproduction, four-month-old zebrafish were exposed to TEB (0, DMSO, 0.4 mg/L, 0.8 mg/L, and 1.6 mg/L) for 21 days. After exposure, the accumulations of TEB in gonads were observed and the cumulative egg production was evidently decreased. The decline of fertilization rate in F1 embryos was also observed. Then the changes in sperm motility and histomorphology of gonads were discovered, evaluating that TEB had adverse effects on gonadal development. Additionally, we also found the alternations of social behavior, 17β-estradiol (E2) level, and testosterone (T) level. Furthermore, the expression levels of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis and social behavior were remarkably altered. Taken together, it could be concluded that TEB affected the egg production and fertilization rate by interfering with gonadal development, sex hormone secretion, and social behavior, which were eventually attributed to the disruption of the expressions of genes associated with the HPG axis and social behavior. This study provides a new perspective to understanding the mechanism of TEB-induced reproductive toxicity.

Secretoneurin as a Novel Biomarker of Cardiovascular Episodes: Are We There Yet? A Narrative Review

Secretoneurin (SN) is a 33 amino-acid evolutionary conserved neuropeptide from the chromogranin peptide family. SN's main effects may be cardioprotective and are believed to be mediated through its inhibition of calmodulin-dependent kinase II (CaMKII), which influences intracellular calcium handling. SN inhibition of CaMKII suppresses calcium leakage from the sarcoplasmic reticulum through the ryanodine receptor. This action may reduce the risk of ventricular arrhythmias and calcium-dependent remodelling in heart failure. SN is also involved in reducing the intracellular reactive oxygen species concentration, modulating the immune response, and regulating the cell cycle, including apoptosis. SN can predict mortality in different disease states, beyond the classical risk factors and markers of myocardial injury. Plasma SN levels are elevated soon after an arrhythmogenic episode. In summary, SN is a novel biomarker with potential in cardiovascular medicine, and probably beyond.

Tuning the Size of Large Dense-Core Vesicles and Quantal Neurotransmitter Release via Secretogranin II Liquid-Liquid Phase Separation

Large dense-core vesicles (LDCVs) are larger in volume than synaptic vesicles, and are filled with multiple neuropeptides, hormones, and neurotransmitters that participate in various physiological processes. However, little is known about the mechanism determining the size of LDCVs. Here, it is reported that secretogranin II (SgII), a vesicle matrix protein, contributes to LDCV size regulation through its liquid-liquid phase separation in neuroendocrine cells. First, SgII undergoes pH-dependent polymerization and the polymerized SgII forms phase droplets with Ca²⁺ in vitro and in vivo. Further, the Ca²⁺ -induced SgII droplets recruit reconstituted bio-lipids, mimicking the LDCVs biogenesis. In addition, SgII knockdown leads to significant decrease of the quantal neurotransmitter release by affecting LDCV size, which is differently rescued by SgII truncations with different degrees of phase separation. In conclusion, it is shown that SgII is a unique intravesicular matrix protein undergoing liquid-liquid phase separation, and present novel insights into how SgII determines LDCV size and the quantal neurotransmitter release.

Vasoactive Intestinal Peptide Indirectly Elicits Pituitary LH Secretion Independent of GnRH in Female Zebrafish

Vasoactive intestinal peptide (Vip) regulates luteinizing hormone (LH) release through the direct regulation of gonadotropin-releasing hormone (GnRH) neurons at the level of the brain in female rodents. However, little is known regarding the roles of Vip in teleost reproduction. Although GnRH is critical for fertility through the regulation of LH secretion in vertebrates, the exact role of the hypophysiotropic GnRH (GnRH3) in zebrafish is unclear since GnRH3 null fish are reproductively fertile. This phenomenon raises the possibility of a redundant regulatory pathway(s) for LH secretion in zebrafish. Here, we demonstrate that VipA (homologues of mammalian Vip) both inhibits and induces LH secretion in zebrafish. Despite the observation that VipA axons may reach the pituitary proximal pars distalis including LH cells, pituitary incubation with VipA in vitro, and intraperitoneal injection of VipA, did not induce LH secretion and lhβ mRNA expression in sexually mature females, respectively. On the other hand, intracerebroventricular administration of VipA augmented plasma LH levels in both wild-type and gnrh3-/- females at 1 hour posttreatment, with no observed changes in pituitary GnRH2 and GnRH3 contents and gnrh3 mRNA levels in the brains. While VipA's manner of inhibition of LH secretion has yet to be explored, the stimulation seems to occur via a different pathway than GnRH3, dopamine, and 17β-estradiol in regulating LH secretion. The results indicate that VipA induces LH release possibly by acting with or through a non-GnRH factor(s), providing proof for the existence of functional redundancy of LH release in sexually mature female zebrafish.

Neuroendocrine Control of Reproduction in Teleost Fish: Concepts and Controversies

During the teleost radiation, extensive development of the direct innervation mode of hypothalamo-pituitary communication was accompanied by loss of the median eminence typical of mammals. Cells secreting follicle-stimulating hormone and luteinizing hormone cells are directly innervated, distinct populations in the anterior pituitary. So far, ∼20 stimulatory and ∼10 inhibitory neuropeptides, 3 amines, and 3 amino acid neurotransmitters are implicated in the control of reproduction. Positive and negative sex steroid feedback loops operate in both sexes. Gene mutation models in zebrafish and medaka now challenge our general understanding of vertebrate neuropeptidergic control. New reproductive neuropeptides are emerging. These include but are not limited to nesfatin 1, neurokinin B, and the secretoneurins. A generalized model for the neuroendocrine control of reproduction is proposed. Hopefully, this will serve as a research framework on diverse species to help explain the evolution of neuroendocrine control and lead to the discovery of new hormones with novel applications. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 10 is February 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Developmental aspects of the hypothalamic-pituitary network related to reproduction in teleost fish

The hypothalamic-pituitary-gonadal axis is the main system that regulates reproduction in vertebrates through a complex network that involves different neuropeptides, neurotransmitters, and pituitary hormones. Considering that this axis is established early on life, the main goal of the present work is to gather information on its development and the actions of its components during early life stages. This review focuses on fish because their neuroanatomical characteristics make them excellent models to study neuroendocrine systems. The following points are discussed: i) developmental functions of the neuroendocrine components of this network, and ii) developmental disruptions that may impact adult reproduction. The importance of the components of this network and their susceptibility to external/internal signals that can alter their specific early functions and/or even the establishment of the reproductive axis, indicate that more studies are necessary to understand this complex and dynamic network.