JAK/STAT signaling in Drosophila muscles controls the cellular immune response against parasitoid infection.

Hairu Yang,Gül Gizem Korkut,Jesper Kronhamn,Jens‐Ola Ekström,Dan Hultmark

doi:10.15252/embr.201540277

Hairu Yang, Gül Gizem Korkut + Show 3 more

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https://doi.org/10.15252/embr.201540277

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Journal: EMBO reports	Publication Date: Sep 27, 2015
Citations: 161	License type: CC BY 4.0

Affiliation: Umeå University, Tampere University

Abstract

The role of JAK/STAT signaling in the cellular immune response of Drosophila is not well understood. Here, we show that parasitoid wasp infection activates JAK/STAT signaling in somatic muscles of the Drosophila larva, triggered by secretion of the cytokines Upd2 and Upd3 from circulating hemocytes. Deletion of upd2 or upd3, but not the related os (upd1) gene, reduced the cellular immune response, and suppression of the JAK/STAT pathway in muscle cells reduced the encapsulation of wasp eggs and the number of circulating lamellocyte effector cells. These results suggest that JAK/STAT signaling in muscles participates in a systemic immune defense against wasp infection.

Highlights

When infected, Drosophila melanogaster activates humoral as well as cellular immune responses [1,2,3,4,5]
We found that JAK/STAT signaling in somatic muscles plays an important role in the response of Drosophila larvae against wasp infection, besides its role in hemocytes and hematopoietic tissue
The wasp-induced JAK/ STAT activity in muscles was significantly reduced by suppression of either gene (Fig 4J). These results indicate that Unpaired 2 (Upd2) and Unpaired 3 (Upd3), produced in hemocytes of infected larvae, act additively or synergistically to activate JAK/STAT signaling in somatic muscles

Summary

Introduction

Drosophila melanogaster activates humoral as well as cellular immune responses [1,2,3,4,5]. Best understood is the humoral immune response to bacterial or fungal infections, which leads to the production of several antimicrobial peptides. This response is mainly controlled by two NF-jB-like signaling pathways, the Toll and the immune deficiency (IMD) pathways [6,7,8], with somewhat different specificities toward different microorganisms [2,3]. Two classes of blood cells, or hemocytes, are present in healthy larvae: plasmatocytes, which are phagocytically active, and crystal cells, which deposit melanin around wound sites [9]. Components of the phenol oxidase cascade, possibly from the crystal cells but more likely from the lamellocytes [11], cause melanization of the wasp egg

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