*Article* **Ontogenetic Pattern Changes of Nucleobindin-2**/**Nesfatin-1 in the Brain and Intestinal Bulb of the Short Lived African Turquoise Killifish**

**Alessia Montesano 1,2,3,**†**, Elena De Felice 4,**†**, Adele Leggieri 1, Antonio Palladino 5, Carla Lucini 1, Paola Scocco 4, Paolo de Girolamo 1, Mario Baumgart 2,**‡ **and Livia D'Angelo 1,6,\*,**‡


Received: 21 November 2019; Accepted: 24 December 2019; Published: 31 December 2019

**Abstract:** Nesfatin-1 (Nesf-1) was identified as an anorexigenic and well conserved molecule in rodents and fish. While tissue distribution of NUCB2 (Nucleobindin 2)/Nesf-1 is discretely known in vertebrates, reports on ontogenetic expression are scarce. Here, we examine the age-related central and peripheral expression of NUCB2/Nesf-1 in the teleost African turquoise killifish *Nothobranchius furzeri*, a consolidated model organism for aging research. We focused our analysis on brain areas responsible for the regulation of food intake and the rostral intestinal bulb, which is analogous of the mammalian stomach. We hypothesize that in our model, the stomach equivalent structure is the main source of NUCB2 mRNA, displaying higher expression levels than those observed in the brain, mainly during aging. Remarkably, its expression significantly increased in the rostral intestinal bulb compared to the brain, which is likely due to the typical anorexia of aging. When analyzing the pattern of expression, we confirmed the distribution in diencephalic areas involved in food intake regulation at all age stages. Interestingly, in the rostral bulb, NUCB2 mRNA was localized in the lining epithelium of young and old animals, while Nesf-1 immunoreactive cells were distributed in the submucosae. Taken together, our results represent a useful basis for gaining deeper knowledge regarding the mechanisms that regulate food intake during vertebrate aging.

**Keywords:** Nesf-1; vertebrate; *Nothobranchius furzeri*; aging; brain-gut axis
