Nucleobindins are a class of secreted, multi-domain Ca2+ binding proteins that interact with nucleic acids. Two nucleobindins, nucleobindin-1 (NUCB1) and nucleobindin-2 (NUCB2) have been identified so far. In 2006, nesfatin-1, an 82 amino acid peptide encoded in NUCB2 was discovered. Nesfatin-1 is an anorexigenic and insulinotropic peptide found abundantly in hypothalamus, pancreas and stomach. Meal responsive insulin secretion is regulated by glucagon like peptide-1 (GLP-1), glucose dependent insulinotropic polypeptide (GIP), peptide YY (PYY) and cholecystokinin (CCK) secreted by intestinal mucosal cells. Since both nesfatin-1 and intestinal hormones modulate insulin secretion, nesfatin-1 could regulate intestinal hormones to elicit its insulinotropic action. Nucleobindin-1 primarily regulates Ca2+ homeostasis. Like NUCB2, NUCB1 is also present in the pancreas, stomach, intestine and pituitary. NUCB2 has a high similarity (62% in humans) to NUCB1. Both proteins also retain their prohormone convertase cleavage sites. However, no information exists on whether NUCB1 encodes bioactive peptides. The fact that NUCB1 is a secreted protein suggests an endocrine function for NUCB1 and/or its encoded peptide. This research hypothesizes that nesfatin-1 is enterotropic, and NUCB1 encodes an insulinotropic nesfatin-1-like peptide (NLP). Nesfatin-1 protein expression was found in STC-1 cells and it co-localized GLP-1, GIP, CCK and PYY in mouse enteroendocrine cells. Treatment of STC-1 cells with nesfatin-1 stimulated GLP-1, GIP, CCK mRNA expression and protein secretion, while opposite effects were found for PYY. In silico analysis of the NUCB1 amino acid sequence found a 77 amino acid NLP. Mouse pancreatic islets and MIN6 cells express NUCB1 mRNA and protein. NUCB1 was co-localized with insulin in mouse pancreatic islets. While treatment of cells with synthetic NLP increased preproinsulin mRNA expression and secretion, a scrambled peptide based on NLP was ineffective, indicating that the specific amino acid sequence is crucial for its insulinotropic action. Overall, the data presented supports the hypotheses. The studies reaffirm NUCB2 expression in intestine and provide the first set of evidence for nesfatin-1 regulation of enteric hormones. It also found a novel NUCB1 encoded insulinotropic NLP that could elicit other functions of nesfatin-1.

Nesfatin-1 is an eighty two amino acid long peptide cleaved from the N-terminal of its precursor protein, nucleobindin-2 (NUCB2). In addition to its metabolic actions, nesfatin-1 is also involved in modulating cardiovascular functions in rodents. Intracereberoventricular injection of nesfatin-1 increased mean arterial pressure in rats. In rats, nesfatin-1 acts as a post-conditioning agent and elicits cardioprotection against ischemia-reperfusion injury. It also affects the contraction and relaxation of the heart in rats in a dose dependent manner. Nesfatin-1 is emerging as a regulator of cardiovascular functions in rodents. However, whether nesfatin-1 regulates the cardiovascular system of non-mammals remain unknown. We hypothesized that nesfatin-1 is a modulator of cardiovascular functions in zebrafish. Here we characterized endogenous nesfatin-1 in zebrafish heart, and its effects on zebrafish cardiovascular physiology. We found that zebrafish cardiomyocytes express NUCB2 mRNA and nesfatin-1-like immunoreactivity. While NUCB2 mRNA was lower in unfed fish at 1 hour post-regular feeding time compared to the fish at 0 hour time point, it was observed that chronic food deprivation did not alter NUCB2 mRNA expression in zebrafish heart. Ultrasound imaging of zebrafish heart at 15 minutes post-intraperitoneal injection of nesfatin-1 (50 ng/g, 250 ng/g and 500 ng/g body weight) showed a dose-dependent inhibition of end-diastolic volume, but not end-systolic volume, while a significant increase in end-diastolic volume was found at the lowest dosage. However, these combined effects did not alter the stroke volume. A dose dependent decrease in heart rate and cardiac output was observed in zebrafish that received nesfatin-1. Nesfatin-1 caused a significant increase in the expression of Atp2a2a mRNA encoding the calcium-handling pump, SERCA2a, while it has no effects on the expression of calcium handling protein RyR1b encoding mRNA. NUCB2 mRNA and NUCB2/nesfatin-1 like immunoreactivity was detected in the cytoplasm of mouse HL-1 cardiomyocytes. High glucose increased NUCB2 mRNA expression in HL-1 cells. Genes involved in apoptosis, including Akt1, Caspases 1, 2, 3, and TNF were upregulated in the presence of 10 nM nesfatin-1. We also observed that NUCB2 mRNA expression was significantly increased in C57BL/6 mice heart in the presence of high glucose, whereas in diet induced obese C57BL/6 mice, NUCB2 mRNA expression was not altered. Together, our data supports the hypothesis that nesfatin-1 is expressed in the cardiovascular system of mouse and fish, and that nesfatin-1 modulates cardiovascular physiology in zebrafish.

A obesidade é caracterizada como uma doença crônica na qual há excesso de massa corporal na forma de gordura, resultando em um grande risco de comorbidades. A saúde humana depende da regulação do metabolismo energético, isto é, a relação entre o consumo alimentar e o gasto energético, processo este de integração entre o Sistema Nervoso Central (SNC) e os órgãos periféricos. Alguns estímulos parecem provocar alterações nas concentrações de Nesfatin-1 (NES1) e Grelina Acilada (GRE), peptídeos envolvidos na homeostase energética, como a obesidade, dieta/refeição hiperlipídica e exercício físico. Assim, o objetivo principal do estudo foi verificar e comparar o efeito agudo do exercício aeróbio sobre o apetite e as concentrações plasmáticas de Grelina Acilada e Nesfatin-1 em homens eutróficos e obesos. Na revisão da literatura, os métodos empregados foram pesquisa bibliográfica, culminado com um artigo de hipótese sobre o tema. No estudo original, onze indivíduos eutróficos (EUT) e dez obesos (OB), sedentários, participaram de 2 protocolos: Controle (Con) e Exercício (Ex). No Ex, os participantes pedalaram durante 45 minutos a 50% do VO2max e, logo após, receberam uma refeição hiperlipídica e permaneceram em repouso por mais 120 minutos. No Con, os participantes ficaram em repouso durante todo o período. Cinco coletas sanguíneas foram realizadas, em cada protocolo. Os níveis de GRE, NES1, triglicerídeos (TG), colesterol total (CT), HDL, LDL e glicose foram mensurados. O apetite (sensação de fome) foi avaliado por meio de uma escala visual. O exercício foi capaz de suprimir os níveis de GRE e apetite nos EUT, mas não nos OB, logo após a sessão. Não houve alteração de NES1 ao longo dos protocolos. Houve uma correlação inversa entre as concentrações plasmáticas em jejum de GRE e NES1 (somente nos EUT) e associação positiva de NES1 com IMC (para ambos os grupos). Este estudo mostrou que o exercício aeróbio agudo induziu supressão de GRE e do apetite em EUT, o que não ocorre em OB. Deste modo, refeições contendo grandes quantidades de gorduras devem ser desencorajadas nesta população. / Obesity is characterized as a chronic disease which there is an excess of body mass as fat, resulting in a greater risk of comorbidities. Human health depends on the regulation of energy metabolism, i.e. the relationship between food intake and energy expenditure, an integration process between the Central Nervous System (CNS) and peripheral organs. Some stimuli, such as obesity, high fat meal/diet, exercise, cause changes in concentrations of peptides involved in energy homeostasis, such as Nesfatin-1 (NES1) and Acylated Ghrelin (GRE). Thus, the main objective of the study was to determine and compare the acute effect of aerobic exercise on appetite and plasma concentrations of acylated ghrelin and nesfatin-1 in normal weight and obese men. In the literature review, the methods employed were bibliographic research, culminating in a hypothesis article about the topic. In the original study, eleven normal weight (EUT) and ten obese (OB), sedentary, participated in two protocols: control (Con) and exercise (Ex). In Ex, they cycled for 45 minutes at 50% VO2max, and soon after, received a high-fat meal and remained resting for over 120 minutes. In Con, the participants were at rest throughout the whole period. Five blood samples were taken in each protocol. The levels of GRE, NES1, triglycerides (TG), total cholesterol (TC), HDL-cholesterol, LDL-cholesterol and glucose were determined. Appetite (hunger sensation) was assessed using a visual scale. The exercise induced suppression of GRE and appetite levels in EUT but not in OB after the session. There was no change in NES1 over protocols. There was an negative correlation between fasting plasma concentrations of NES1 and GRE (only in EUT) and a positive association with BMI and NES1 (for both groups). This study showed that acute aerobic exercise induced suppression of appetite and GRE in EUT, which does not occur in OB. Thus, meals containing high amounts of fats in this population should be discouraged.

A obesidade é caracterizada como uma doença crônica na qual há excesso de massa corporal na forma de gordura, resultando em um grande risco de comorbidades. A saúde humana depende da regulação do metabolismo energético, isto é, a relação entre o consumo alimentar e o gasto energético, processo este de integração entre o Sistema Nervoso Central (SNC) e os órgãos periféricos. Alguns estímulos parecem provocar alterações nas concentrações de Nesfatin-1 (NES1) e Grelina Acilada (GRE), peptídeos envolvidos na homeostase energética, como a obesidade, dieta/refeição hiperlipídica e exercício físico. Assim, o objetivo principal do estudo foi verificar e comparar o efeito agudo do exercício aeróbio sobre o apetite e as concentrações plasmáticas de Grelina Acilada e Nesfatin-1 em homens eutróficos e obesos. Na revisão da literatura, os métodos empregados foram pesquisa bibliográfica, culminado com um artigo de hipótese sobre o tema. No estudo original, onze indivíduos eutróficos (EUT) e dez obesos (OB), sedentários, participaram de 2 protocolos: Controle (Con) e Exercício (Ex). No Ex, os participantes pedalaram durante 45 minutos a 50% do VO2max e, logo após, receberam uma refeição hiperlipídica e permaneceram em repouso por mais 120 minutos. No Con, os participantes ficaram em repouso durante todo o período. Cinco coletas sanguíneas foram realizadas, em cada protocolo. Os níveis de GRE, NES1, triglicerídeos (TG), colesterol total (CT), HDL, LDL e glicose foram mensurados. O apetite (sensação de fome) foi avaliado por meio de uma escala visual. O exercício foi capaz de suprimir os níveis de GRE e apetite nos EUT, mas não nos OB, logo após a sessão. Não houve alteração de NES1 ao longo dos protocolos. Houve uma correlação inversa entre as concentrações plasmáticas em jejum de GRE e NES1 (somente nos EUT) e associação positiva de NES1 com IMC (para ambos os grupos). Este estudo mostrou que o exercício aeróbio agudo induziu supressão de GRE e do apetite em EUT, o que não ocorre em OB. Deste modo, refeições contendo grandes quantidades de gorduras devem ser desencorajadas nesta população. / Obesity is characterized as a chronic disease which there is an excess of body mass as fat, resulting in a greater risk of comorbidities. Human health depends on the regulation of energy metabolism, i.e. the relationship between food intake and energy expenditure, an integration process between the Central Nervous System (CNS) and peripheral organs. Some stimuli, such as obesity, high fat meal/diet, exercise, cause changes in concentrations of peptides involved in energy homeostasis, such as Nesfatin-1 (NES1) and Acylated Ghrelin (GRE). Thus, the main objective of the study was to determine and compare the acute effect of aerobic exercise on appetite and plasma concentrations of acylated ghrelin and nesfatin-1 in normal weight and obese men. In the literature review, the methods employed were bibliographic research, culminating in a hypothesis article about the topic. In the original study, eleven normal weight (EUT) and ten obese (OB), sedentary, participated in two protocols: control (Con) and exercise (Ex). In Ex, they cycled for 45 minutes at 50% VO2max, and soon after, received a high-fat meal and remained resting for over 120 minutes. In Con, the participants were at rest throughout the whole period. Five blood samples were taken in each protocol. The levels of GRE, NES1, triglycerides (TG), total cholesterol (TC), HDL-cholesterol, LDL-cholesterol and glucose were determined. Appetite (hunger sensation) was assessed using a visual scale. The exercise induced suppression of GRE and appetite levels in EUT but not in OB after the session. There was no change in NES1 over protocols. There was an negative correlation between fasting plasma concentrations of NES1 and GRE (only in EUT) and a positive association with BMI and NES1 (for both groups). This study showed that acute aerobic exercise induced suppression of appetite and GRE in EUT, which does not occur in OB. Thus, meals containing high amounts of fats in this population should be discouraged.

A obesidade é caracterizada como uma doença crônica na qual há excesso de massa corporal na forma de gordura, resultando em um grande risco de comorbidades. A saúde humana depende da regulação do metabolismo energético, isto é, a relação entre o consumo alimentar e o gasto energético, processo este de integração entre o Sistema Nervoso Central (SNC) e os órgãos periféricos. Alguns estímulos parecem provocar alterações nas concentrações de Nesfatin-1 (NES1) e Grelina Acilada (GRE), peptídeos envolvidos na homeostase energética, como a obesidade, dieta/refeição hiperlipídica e exercício físico. Assim, o objetivo principal do estudo foi verificar e comparar o efeito agudo do exercício aeróbio sobre o apetite e as concentrações plasmáticas de Grelina Acilada e Nesfatin-1 em homens eutróficos e obesos. Na revisão da literatura, os métodos empregados foram pesquisa bibliográfica, culminado com um artigo de hipótese sobre o tema. No estudo original, onze indivíduos eutróficos (EUT) e dez obesos (OB), sedentários, participaram de 2 protocolos: Controle (Con) e Exercício (Ex). No Ex, os participantes pedalaram durante 45 minutos a 50% do VO2max e, logo após, receberam uma refeição hiperlipídica e permaneceram em repouso por mais 120 minutos. No Con, os participantes ficaram em repouso durante todo o período. Cinco coletas sanguíneas foram realizadas, em cada protocolo. Os níveis de GRE, NES1, triglicerídeos (TG), colesterol total (CT), HDL, LDL e glicose foram mensurados. O apetite (sensação de fome) foi avaliado por meio de uma escala visual. O exercício foi capaz de suprimir os níveis de GRE e apetite nos EUT, mas não nos OB, logo após a sessão. Não houve alteração de NES1 ao longo dos protocolos. Houve uma correlação inversa entre as concentrações plasmáticas em jejum de GRE e NES1 (somente nos EUT) e associação positiva de NES1 com IMC (para ambos os grupos). Este estudo mostrou que o exercício aeróbio agudo induziu supressão de GRE e do apetite em EUT, o que não ocorre em OB. Deste modo, refeições contendo grandes quantidades de gorduras devem ser desencorajadas nesta população. / Obesity is characterized as a chronic disease which there is an excess of body mass as fat, resulting in a greater risk of comorbidities. Human health depends on the regulation of energy metabolism, i.e. the relationship between food intake and energy expenditure, an integration process between the Central Nervous System (CNS) and peripheral organs. Some stimuli, such as obesity, high fat meal/diet, exercise, cause changes in concentrations of peptides involved in energy homeostasis, such as Nesfatin-1 (NES1) and Acylated Ghrelin (GRE). Thus, the main objective of the study was to determine and compare the acute effect of aerobic exercise on appetite and plasma concentrations of acylated ghrelin and nesfatin-1 in normal weight and obese men. In the literature review, the methods employed were bibliographic research, culminating in a hypothesis article about the topic. In the original study, eleven normal weight (EUT) and ten obese (OB), sedentary, participated in two protocols: control (Con) and exercise (Ex). In Ex, they cycled for 45 minutes at 50% VO2max, and soon after, received a high-fat meal and remained resting for over 120 minutes. In Con, the participants were at rest throughout the whole period. Five blood samples were taken in each protocol. The levels of GRE, NES1, triglycerides (TG), total cholesterol (TC), HDL-cholesterol, LDL-cholesterol and glucose were determined. Appetite (hunger sensation) was assessed using a visual scale. The exercise induced suppression of GRE and appetite levels in EUT but not in OB after the session. There was no change in NES1 over protocols. There was an negative correlation between fasting plasma concentrations of NES1 and GRE (only in EUT) and a positive association with BMI and NES1 (for both groups). This study showed that acute aerobic exercise induced suppression of appetite and GRE in EUT, which does not occur in OB. Thus, meals containing high amounts of fats in this population should be discouraged.

Le maintien de notre poids corporel résulte d'un équilibre entre les dépenses et les apports énergétiques. Cet équilibre appelé « homéostasie énergétique » implique un grand nombre de molécules. Parmi elles, la nesfatine-1, découverte en 2006, est un peptide de 82 acides aminés issu du clivage de la protéine NUCB2. L'intérêt généré par la nesfatine-1 réside dans son action anorexigène exercée indépendamment de la signalisation à la leptine. La nesfatine-1 est exprimée dans plusieurs organes tels que le tissu adipeux, l'estomac, le pancréas, ainsi que le cerveau. Dans le cerveau, son expression se limite principalement à quelques groupes neuronaux localisés dans l'hypothalamus et le complexe vagal dorsal. Au cours de ce travail, nous avons analysé la sensibilité des neurones exprimant NUCB2/nesfatine-1 aux signaux périphériques physiologiques et physiopathologiques affectant la prise alimentaire. Nous montrons que ces neurones sont sensibles à une hypoglycémie et qu'ils pourraient contribuer à la contre-régulation mise en place afin de rétablir la glycémie de base. De plus, nous montrons qu'ils sont activés en réponse à deux stimuli inflammatoires : l'administration de lipopolysaccharide et l'intoxication alimentaire avec une mycotoxine appelée déoxynivalénol. Ainsi, les neurones exprimant NUCB2/nesfatine-1 pourraient contribuer au développement de l'anorexie inflammatoire. Cette étude a constitué la première mise en évidence d'une implication de ce peptide en situation pathologique. L'ensemble de ces résultats suggère qu'en plus de son effet satiétogène, la nesfatine-1 participe à la signalisation centrale impliquée dans la glucodétection et les réponses inflammatoires. / The long term maintenance of body weight results from a balance between energy expenditure and intake. This balance, called “energy homeostasis”, involves a large number of molecules. Among these, nesfatin-1, discovered in 2006, is an 82 amino-acid peptide derived from the cleavage of the protein NUCB2. The interest generated by nesfatin-1 lies in its anorexigenic effect performed independently of leptin signalization. Nesfatin-1 is expressed in several organs such as adipose tissue, stomach, pancreas, and brain. In the brain, its expression is limited to a few neuronal groups located in the hypothalamus and dorsal vagal complex. In this work, we analyzed the sensitivity of NUCB2/nesfatin-1-expressing neurons to physiological and physiopathological peripheral signals affecting food intake. We show that these neurons are sensitive to hypoglycemia and that they could contribute to the counter-regulatory response established in order to restore the basal blood glucose level. Moreover, we show that they are activated in response to two inflammatory stimuli: lipopolysaccharide administration and food intoxication with a mycotoxin named deoxynivalenol. So, NUCB2/nesfatin-1-expressing neurons could contribute to the development of inflammatory anorexia. This study was the first evidence of an involvement of this peptide in a pathological situation. Taken together, these results suggest that in addition to its satiating effect, nesfatin-1 participates in the central signalization involved in glucodetection and inflammatory responses.