Thioester-Containing Proteins 2 and 4 Affect the Metabolic Activity and Inflammation Response in Drosophila

Abstract

is an outstanding model for studying host antipathogen defense. Although substantial progress has been made in understanding how metabolism and immunity are interrelated in flies, little information has been obtained on the molecular players that regulate metabolism and inflammation in during pathogenic infection. Recently, we reported that the inactivation of thioester-containing protein 2 () and promotes survival and decreases the bacterial burden in flies upon infection with the virulent pathogens and Here, we investigated physiological and pathological defects in mutant flies in response to challenge. We find that and loss-of-function mutant flies contain increased levels of carbohydrates and triglycerides in the presence or absence of infection. We also report that infection leads to higher levels of nitric oxide and reduced transcript levels of the apical caspase-encoding gene in and mutants. We show that and are upregulated mainly in the fat body rather than the gut in -infected wild-type flies and that mutants contain decreased numbers of bacteria in both tissue types. We propose that the inactivation of or in adult flies results in lower levels of inflammation and increased energy reserves in response to , which could confer a survival-protective effect during the initial hours of infection.

A New Assessment of Thioester-Containing Proteins Diversity of the Freshwater Snail Biomphalaria glabrata

“…Moreover, it was recently evidenced that some invertebrate TEPs also play roles in other functions than immunity. Drosophila MCR was found to be implicated in development [73], nitric oxide regulation, and metabolic processes [74,75], while AgTEP1 was shown to increase male fertility [76].…”

Partner-specific induction ofSpodoptera frugiperdaimmune genes in response to the entomopathogenic nematobacterial complexSteinernema carpocapsae-Xenorhabdus nematophila

“…In the fat body, the Jak-Stat pathway has mainly been shown to induce the expression of cytokines (103) and of a putative opsonin belonging to the TEP family (104). Remarkably, several Tep genes have been shown to participate in antibacterial immunity after NBC infestation in D. melanogaster (91, 105–107). All of these down-regulations could thus impair the insect’s immune response to the NBC.…”

Thioester-Containing Proteins in the Drosophila melanogaster Immune Response against the Pathogen Photorhabdus

“…Because certain TEPs in D. melanogaster were shown to play a regulatory role by inducing humoral and cellular immune activities against Photorhabdus pathogens [18,19,22], these molecules also form a reliable indicator for their potential multipurpose involvement in linking host immunity and metabolism in the presence of pathogenic bacteria. Of note, injection of P. luminescens into the hemocoel of background wild-type flies upregulates both Tep2 and Tep4 in the fat body as well as Tep4 in the gut, whereas injection of P. asymbiotica increases the expression of Tep4 in the fat body only (Figure 1) [32]. Although the tissue-specific expression pattern of Tep genes in D. melanogaster varies upon infection with different bacterial pathogens [33], these results demonstrate that certain Tep genes are expressed in the two metabolic tissues of the fly-fat body and gut-in response to Photorhabdus systemic infection.…”

“…To address these issues, a recent study monitored the metabolic activity in D. melanogaster TEP-deficient flies during response to infection by two Photorhabdus species as well as by a nonpathogenic strain of E. coli used as control and estimated the amounts of different metabolites including carbohydrates and lipids [32]. Results from these experiments first revealed that trehalose levels are drastically affected in flies with compromised Tep2, regardless of whether they are infected with pathogenic Photorhabdus bacteria or nonpathogenic E. coli.…”

“…Variations in insect survival and pathogen load often correlate with changes in host innate immune response, which is often difficult to separate from stress or inflammatory responses to a given microbial challenge [34,35]. A recent study expanded on this topic by examining the contribution of Tep gene activity to the stress and inflammation response to infection by Photorhabdus bacteria [32]. Because the nitrite level (a by-product of nitric oxide synthesis) is an indicator for stress response in the fly [36], the authors estimated nitrite amounts produced in D. melanogaster adults compromised for either Tep2 or Tep4 in the context of infection with either P. luminescens or P. asymbiotica.…”