Serotonin regulates an acyl-CoA-binding protein (ACBP) gene expression in the midgut of Rhodnius prolixus

• Published in: Insect biochemistry and molecular biology Vol. 40; no. 2; pp. 119 - 125
• Main Authors: Alves-Bezerra, Michele, Majerowicz, David, Grillo, Luciano A.M., Tremonte, Hugo, Almeida, Caroline B., Braz, Glória R.C., Sola-Penna, Mauro, Paiva-Silva, Gabriela O., Gondim, Katia C.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2010
• Subjects: 5-HT; ACBP; Acyl-CoA ester; Amino Acid Sequence; Animals; antagonists; Base Sequence; binding proteins; biochemical pathways; coenzyme A; Diazepam Binding Inhibitor - metabolism; DNA; esters; Female; females; gene expression; gene expression regulation; Gene Expression Regulation - physiology; genome; hematophagy; hemolymph; insect pests; insect vectors; Lipid; midgut; Molecular Sequence Data; molecular weight; nucleotide sequences; polymerase chain reaction; protein synthesis; Reverse Transcriptase Polymerase Chain Reaction; Rhodnius - genetics; Rhodnius prolixus; Serotonin; Serotonin - physiology; transcription (genetics); Acyl-CoA ester; Rhodnius prolixus; Serotonin; 5-HT; ACBP; Lipid
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2010.01.002

Acyl-CoA esters have many intracellular functions, acting as energy source, substrate for metabolic processes and taking part in cell signaling. The acyl-CoA-binding protein (ACBP), a highly conserved 10 kDa intracellular protein, binds long- and medium-chain acyl-CoA esters with very high affinity, directing them to specific metabolic routes and protecting them from hydrolysis. An ACBP gene sequence was identified in the genome of Rhodnius prolixus. This ACBP gene ( RpACBP-1) was expressed in all analyzed tissues and quantitative PCR showed that expression was highest in posterior midgut. In this tissue, ACBP gene expression increased in the first day after blood meal (∼10-fold) and then decreased to unfed levels in the seventh day after meal. Injection of serotonin (5-hydroxytryptamine; 5-HT), a neuroamine released in the hemolymph after the start of feeding, increased the expression of this gene in the midgut of unfed females, reaching levels similar to those observed in fed insects. This effect of injected 5-HT was inhibited by spiperone, an antagonist of 5-HT mammalian receptors, that was also able to block the physiological increase in RpACBP-1 expression observed after feeding. Injection of cholera toxin or dibutyryl-cAMP also resulted in the stimulation of this gene expression. These data reveal a transcriptional regulatory mechanism in R. prolixus, that is triggered by 5-HT. In this way, a novel role for 5-HT is proposed, as a regulator of ACBP gene expression and, consequently, taking part in the control of lipid metabolism.