The Impact of the Angiotensin-Converting Enzyme Inhibitor Lisinopril on Metabolic Rate in Drosophila melanogaster

Abstract

Evidence suggests that angiotensin-converting enzyme inhibitors (ACEIs) may increase metabolic rate by promoting thermogenesis, potentially through enhanced fat oxidation and improved insulin. More research is, however, needed to understand this intricate process. In this study, we used 22 lines from the Drosophila Genetic Reference Panel to assess the metabolic rate of virgin female and male flies that were either fed a standard medium or received lisinopril for one week or five weeks. We demonstrated that lisinopril affects the whole-body metabolic rate in Drosophila melanogaster in a genotype-dependent manner. However, the effects of genotypes are highly context-dependent, being influenced by sex and age. Our findings also suggest that lisinopril may increase the Drosophila metabolic rate via the accumulation of a bradykinin-like peptide, which, in turn, enhances cold tolerance by upregulating Ucp4b and Ucp4c genes. Finally, we showed that knocking down Ance, the ortholog of mammalian ACE in Malpighian/renal tubules and the nervous system, leads to opposite changes in metabolic rate, and that the effect of lisinopril depends on Ance in these systems, but in a sex- and age-specific manner. In conclusion, our results regarding D. melanogaster support existing evidence of a connection between ACEI drugs and metabolic rate while offering new insights into this relationship.

Keywords: ACE inhibitors; Malpighian/renal tubules; aging; bradykinin; brain; losartan; oxygen consumption rate.

Figure 1

Dual role of angiotensin-converting enzyme (ACE). ACE converts Angiotensin I into Angiotensin II and degrades bradykinin. The drug lisinopril inhibits ACE, whereas losartan antagonizes the binding of Angiotensin II to its type-1 receptor.

Figure 2

Changes in metabolic rate induced by lisinopril treatment in 22 DGRP lines. The response to lisinopril is influenced by genotype, sex, and age. Data report the means ± standard error of whole-body oxygen consumption rate adjusted for live body weight (n = 8–10 individual flies).

Figure 3

Sensitivity of metabolic rate to lisinopril. (a,b) Values represent sensitivity index in DGRP young (panel (a)) and old (panel (b)) flies, averaged over sex. Sensitivity indices were calculated by taking the difference in the average oxygen consumption rate between lisinopril-treated and untreated flies of each genotype and dividing it by the average difference in treated and untreated flies across all genotypes. Lines are ranked by their sensitivity, with positive values indicating a higher metabolic rate with lisinopril, relative to untreated and negative values indicating a lower metabolic rate.

Figure 4

Lisinopril does not alter the metabolic rate through changes in locomotor activity. (a) There is no significant effect of lisinopril on the climbing ability of DGRP lines displaying the greatest change in metabolic rate in response to lisinopril at one week of age. Data report climbing indices for untreated (white dots) and lisinopril-treated (red dots) flies averaged over both sexes and ages. (b) The effect of lisinopril on the climbing ability of DGRP lines displaying the greatest change in metabolic rate in response to lisinopril at five weeks of age depends on genotype and sex. **** p < 0.0001 after post hoc Tukey’s tests for multiple comparisons. In both panels, error bars represent standard errors.

Figure 5

Losartan affects metabolic rate in D. melanogaster. (a,b) DGRP lines exhibiting the greatest change in metabolic rate in response to lisinopril in young or old flies received losartan for one week (panel (a)) and five weeks (panel (b)), respectively. In both panels, data are averaged over both sexes and error bars represent standard errors. Significant comparisons within each DGRP line were determined by post hoc Tukey’s tests at p < 0.05 and are indicated by different letters.

Figure 6

Effects of lisinopril on acute cold tolerance and UCP genes. (a,b) Acute cold tolerance in lisinopril-treated and untreated DGRP lines exhibiting the greatest change in metabolic rate in response to lisinopril at one week (panel (a)) and five weeks (panel (b)) of age. Lisinopril reduces time to recover from chill-induced coma only in DGRP_367 young males (panel (a)) and DGRP_808 old males (panel (b)). (c) The expression of Ucp4b and Ucp4c genes is significantly increased in the head of DGRP_367 young male flies following lisinopril treatment. Transcript levels of each target gene were normalized to rp49 and α-tubulin. In all panels, ** p < 0.01 and **** p < 0.0001 after post hoc Tukey’s tests for multiple comparisons. Error bars represent standard errors.

Figure 7

The effect of lisinopril on whole-body metabolic rate depends on Ance in an organ system-, sex-, and age-specific manner. (a) Metabolic rate of flies with Ance knocked down in Malpighian tubules (c42-Gal4 > Ance-RNAi) and of their corresponding w¹¹¹⁸ isogenic line (control). A four-way ANOVA revealed a significant genotype-by-treatment-by-sex interaction effect on oxygen consumption rate (F_1,301 = 47.40, p < 0.0001). (b) Metabolic rate of flies with Ance knocked down in the nervous system (elav-Gal80 > Ance-RNAi) and of their corresponding w¹¹¹⁸ isogenic line (control). A four-way ANOVA revealed a significant genotype-by-treatment-by-age interaction effect on oxygen consumption rate (F_1,302 = 5.65, p = 0.0180). In both panels, * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001 after post hoc Tukey’s tests for multiple comparisons. Error bars represent standard errors.

Figure 8

Lisinopril increases the whole-body metabolic rate of young flies with AD-like symptoms regardless of sex. A four-way ANOVA revealed a statistically significant effect of the genotype-by-treatment-by-age interaction term (F_1,301 = 3.92, p = 0.0486) on metabolic rate. *** p < 0.001 after post hoc Tukey’s tests for multiple comparisons. Error bars represent standard errors.