Metabolomics provide new insights into mechanisms of Wolbachia-induced paternal defects in Drosophila melanogaster

Abstract

Wolbachia is a group of intracellular symbiotic bacteria that widely infect arthropods and nematodes. Wolbachia infection can regulate host reproduction with the most common phenotype in insects being cytoplasmic incompatibility (CI), which results in embryonic lethality when uninfected eggs fertilized with sperms from infected males. This suggests that CI-induced defects are mainly in paternal side. However, whether Wolbachia-induced metabolic changes play a role in the mechanism of paternal-linked defects in embryonic development is not known. In the current study, we first use untargeted metabolomics method with LC-MS to explore how Wolbachia infection influences the metabolite profiling of the insect hosts. The untargeted metabolomics revealed 414 potential differential metabolites between Wolbachia-infected and uninfected 1-day-old (1d) male flies. Most of the differential metabolites were significantly up-regulated due to Wolbachia infection. Thirty-four metabolic pathways such as carbohydrate, lipid and amino acid, and vitamin and cofactor metabolism were affected by Wolbachia infection. Then, we applied targeted metabolomics analysis with GC-MS and showed that Wolbachia infection resulted in an increased energy expenditure of the host by regulating glycometabolism and fatty acid catabolism, which was compensated by increased food uptake. Furthermore, overexpressing two acyl-CoA catabolism related genes, Dbi (coding for diazepam-binding inhibitor) or Mcad (coding for medium-chain acyl-CoA dehydrogenase), ubiquitously or specially in testes caused significantly decreased paternal-effect egg hatch rate. Oxidative stress and abnormal mitochondria induced by Wolbachia infection disrupted the formation of sperm nebenkern. These findings provide new insights into mechanisms of Wolbachia-induced paternal defects from metabolic phenotypes.

Comparative Ubiquitome Analysis Reveals Deubiquitinating Effects Induced by Wolbachia Infection in Drosophila melanogaster

“…In the present study, we identified 643 DEPs, and again, most (72.78%) were downregulated due to Wolbachia infection. Among those significantly changed proteins, many of them are involved in metabolic processes, which is similar to the results observed in our previous study [ 20 , 31 ] and reports from other groups [ 32 , 33 ]. In studies on human, mouse, boar, and rainbow trout sperm proteome, many sperm proteins were also related to the metabolic processes [ 34 , 35 , 36 , 37 ].…”

Picornavirus infection enhances aspartate by the SLC38A8 transporter to promote viral replication

“…Aspartate transporters contain a large number of proteins, including SLC1A1, SLC1A2, SLC1A3, SLC1A6, SLC1A7, SLC25A12, SLC25A13,SLC38A7, and SLC38A8 [33,34]. To To further investigate the impact of viral infection on aspartate uptake, we detected the aspartate uptake during infection using 13 C-labeled aspartate. The results showed that the level of 13 C-aspartate was significantly enhanced in FMDV-, EV71-, or SVV-infected cells compared to mock-infected cells (Fig 6F ), suggesting that FMDV, EV71, and SVV infection promoted aspartate uptake.…”

“…To further determine the impact of SLC38A8 on FMDV-, EV71-, and SVV-induced aspartate uptake, 13 C-labeled aspartate uptake in WT and SLC38A8 -/cells was assessed during viral infection. There was no change in 13 C-labeled aspartate level in mock-infected WT and SLC38A8 -/cells, while the level of 13 C-labeled aspartate was significantly decreased in FMDV-, EV71-, or SVV-infected SLC38A8 -/cells compared to that of FMDV-, EV71-, or SVV-infected WT cells (Fig 7D).…”

“…Results represent three independent experiments. (D) WT and SLC38A8 -/-PK-15 cells infected with FMDV (MOI 0.5) or SVV (MOI 0.5) were incubated with 13 C-labeled aspartate (2 mM). WT and SLC38A8 -/-HEK-293T cells infected with EV71 (MOI 0.5) were incubated with 13 C-labeled aspartate (2 mM).…”

“…Cellular metabolism mainly involves glycolysis, the tricarboxylic acid cycle (TCA cycle), amino acid metabolism, lipid metabolism, and nucleotide metabolism. Metabolomics, an important means to identify metabolic changes in host cells, is a new method used to identify the special small metabolites of diseases in cancer and other diseases and has already been widely used in biological studies of humans, plants, and animals [10][11][12][13][14]. Glucose is metabolized via glycolysis into pyruvate, which can either be imported to mitochondria for the TCA cycle, or be catalyzed by lactate dehydrogenase (LDH) to generate lactate.…”