Mitochondrial physiology in the major arbovirus vector Aedes aegypti: substrate preferences and sexual differences define respiratory capacity and superoxide production

PLoS One. 2015 Mar 24;10(3):e0120600. doi: 10.1371/journal.pone.0120600. eCollection 2015.

Abstract

Adult females of Aedes aegypti are facultative blood sucking insects and vectors of Dengue and yellow fever viruses. Insect dispersal plays a central role in disease transmission and the extremely high energy demand posed by flight is accomplished by a very efficient oxidative phosphorylation process, which take place within flight muscle mitochondria. These organelles play a central role in energy metabolism, interconnecting nutrient oxidation to ATP synthesis, but also represent an important site of cellular superoxide production. Given the importance of mitochondria to cell physiology, and the potential contributions of this organelle for A. aegypti biology and vectorial capacity, here, we conducted a systematic assessment of mitochondrial physiology in flight muscle of young adult A. aegypti fed exclusively with sugar. This was carried out by determining the activities of mitochondrial enzymes, the substrate preferences to sustain respiration, the mitochondrial bioenergetic efficiency and capacity, in both mitochondria-enriched preparations and mechanically permeabilized flight muscle in both sexes. We also determined the substrates preferences to promote mitochondrial superoxide generation and the main sites where it is produced within this organelle. We observed that respiration in A. aegypti mitochondria was essentially driven by complex I and glycerol 3 phosphate dehydrogenase substrates, which promoted distinct mitochondrial bioenergetic capacities, but with preserved efficiencies. Respiration mediated by proline oxidation in female mitochondria was strikingly higher than in males. Mitochondrial superoxide production was essentially mediated through proline and glycerol 3 phosphate oxidation, which took place at sites other than complex I. Finally, differences in mitochondrial superoxide production among sexes were only observed in male oxidizing glycerol 3 phosphate, exhibiting higher rates than in female. Together, these data represent a significant step towards the understanding of fundamental mitochondrial processes in A. aegypti, with potential implications for its physiology and vectorial capacity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aedes / anatomy & histology
  • Aedes / physiology*
  • Aedes / virology
  • Animals
  • Arboviruses / isolation & purification*
  • Body Size
  • Cytochromes c / metabolism
  • Dengue / transmission
  • Electron Transport Complex I / metabolism
  • Female
  • Glycerolphosphate Dehydrogenase / metabolism
  • Glycerophosphates / metabolism
  • Humans
  • Insect Proteins / metabolism
  • Insect Vectors / physiology*
  • Insect Vectors / virology
  • Male
  • Mitochondria, Muscle / metabolism*
  • NAD / metabolism
  • Oxidation-Reduction
  • Oxygen Consumption*
  • Proline / metabolism
  • Pyruvic Acid / metabolism
  • Sex Characteristics
  • Superoxides / metabolism*

Substances

  • Glycerophosphates
  • Insect Proteins
  • NAD
  • Superoxides
  • Pyruvic Acid
  • Cytochromes c
  • Proline
  • alpha-glycerophosphoric acid
  • Glycerolphosphate Dehydrogenase
  • Electron Transport Complex I

Grants and funding

This work was supported by grants from Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq) (through Institutos Nacionais de Ciência e Tecnologia 2010), Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) (through Jovem Cientista do Nosso Estado E-26/101.492/2010; Cientista do Nosso Estado E-26/102.333/2013; Pronem E-26/111.169/2011). MFO is research scholar from CNPq (Produtividade em Pesquisa—PQ 301571/2009-0). JBRCS is a PAPD-FAPERJ fellow (Apoio à Pós-Doutorado no Estado do Rio de Janeiro, 45879) and AG is a CsF-BJT-CNPq fellow (BJT-Ciências sem Fronteiras, 402409/2012-4). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.