BmGr4 responds to sucrose and glucose and expresses in tachykinin-related peptide-secreting enteroendocrine cells

• Published in: Insect biochemistry and molecular biology 2022-11, Vol.150, p.103858-103858, Article 103858
• Main Authors: Mang, Dingze, Mayu, Kasubuchi, Toyama, Tomoko, Yamagishi, Takayuki, Sato, Ryoichi
• Format: Article
• Language: English
• Subjects: Animals; Bombyx - metabolism; Bombyx mori; Brain; Enteroendocrine cell; Enteroendocrine Cells - metabolism; Glucose - metabolism; Gustatory receptor; Larva - metabolism; Midgut; Neurosecretory cell; Sucrose - metabolism; Sucrose - pharmacology; Tachykinin-related peptides; Tachykinins - metabolism
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2022.103858

The regulatory hormones known as tachykinin-related peptides (TRPs) are identified as brain-gut peptides in insects. Dietary components from mulberry leaves, including glucose, induce secretion of TRPs from Bombyx mori midgut. However, the sensory molecules that recognize these compounds are still unknown. Here, we identified the gustatory receptor, BmGr4, as a sucrose and glucose receptor using Ca2+ imaging. Immunostaining revealed BmGr4 expression not only in the midgut, but also in the brain. In addition, BmGr4 expression was found to co-localize with TRP-expressing cells in both midgut enteroendocrine cells (EECs) and brain neurosecretory cells (NSCs). Furthermore, dietary nutrients after food intake result in an increase of TRP-level in hemolymph of silkworm larvae. These results provide significant circumstantial evidence for the involvement of the sucrose and glucose receptor, BmGr4, in the elicitation of TRP secretion in midgut EECs and brain NSCs. [Display omitted] •BmGr4 was identified as a sucrose and glucose receptor using Ca2+ imaging.•BmGr4 is expressed in cells of anterior midgut, middle midgut, and brain of Bombyx mori larvae.•BmGr4 and tachykinin-related peptides co-expressed in midgut enteroendocrine cells and brain neurosecretory cells.•TRPs are secreted soon after the arrival of ingested food to the place of BmGr4 expressing cells in the midgut.