Université de Fribourg

Hormonal regulation of the humoral innate immune response in Drosophila melanogaster

Flatt, Thomas ; Heyland, Andreas ; Rus, Florentina ; Porpiglia, Ermelinda ; Sherlock, Chris ; Yamamoto, Rochele ; Garbuzov, Alina ; Palli, Subba R. ; Tatar, Marc ; Silverman, Neal

In: The Journal of Experimental Biology, 2008, vol. 21, no. 1, p. 2712-2724

Juvenile hormone (JH) and 20-hydroxy-ecdysone (20E) are highly versatile hormones, coordinating development, growth, reproduction and aging in insects. Pulses of 20E provide key signals for initiating developmental and physiological transitions, while JH promotes or inhibits these signals in a stage-specific manner. Previous evidence suggests that JH and 20E might modulate innate immunity, but...

Université de Fribourg

Drosophila germ-line modulation of insulin signaling and lifespan

Flatt, Thomas ; Min, Kyung-Jin ; D'Alterio, Cecilia ; Villa-Cuesta, Eugenia ; Cumbers, John ; Lehmann, Ruth ; Jones, D. Leanne ; Tatar, Marc

In: Proceedings of the National Academy of Sciences of the United States of America, 2008, vol. 105, no. 17, p. 6368–6373

Ablation of germ-line precursor cells in Caenorhabditis elegans extends lifespan by activating DAF-16, a forkhead transcription factor (FOXO) repressed by insulin/insulin-like growth factor (IGF) signaling (IIS). Signals from the gonad might thus regulate whole-organism aging by modulating IIS. To date, the details of this systemic regulation of aging by the reproductive system are not...

Université de Fribourg

Counting calories in Drosophila diet restriction

Min, Kyung-Jin ; Flatt, Thomas ; Kulaots, Indrek ; Tatar, Marc

In: Experimental Gerontology, 2006, vol. 42, no. 3, p. 247-251

The extension of life span by diet restriction in Drosophila has been argued to occur without limiting calories. Here we directly measure the calories assimilated by flies when maintained on full- and restricted-diets. We find that caloric intake is reduced on all diets that extend life span. Flies on low-yeast diet are long-lived and consume about half the calories of flies on high-yeast diets,...

Université de Fribourg

Juvenile and Steroid Hormones in Drosophila melanogaster Longevity

Flatt, Thomas ; Tu, Meng-Ping ; Tatar, Marc

In: The Handbook of the Biology of Aging, 2006, p. 415-448

This chapter reviews hormonal effects on aging in Drosophila melanogaster. The insect juvenile hormone (JH) is a sesquiterpenoid compound produced by the corpora allata (CA), a pair of endocrine glands with nervous connections to the brain. In pre-adult development and metamorphosis, JH functions as a "status quo" hormone, allowing continued growth after ecdysteroid-induced molting. Metamorphosis...

Université de Fribourg

Comparing thyroid and insect hormone signaling

Flatt, Thomas ; Moroz, Leonid L. ; Tatar, Marc ; Heyland, Andreas

In: Integrative and Comparative Biology, 2006, vol. 46, no. 6, p. 777-794

Transitions between different states of development, physiology, and life history are typically mediated by hormones. In insects, metamorphosis and reproductive maturation are regulated by an interaction between the sesquiterpenoid juvenile hormone (JH) and the steroid 20-hydroxy-ecdysone (20E). In vertebrates and some marine invertebrates, the lipophilic thyroid hormones (THs) affect...

Université de Fribourg

Hormonal pleiotropy and the juvenile hormone regulation of Drosophila development and life history

Flatt, Thomas ; Tu, Meng-Ping ; Tatar, Marc

In: BioEssays, 2005, vol. 27, no. 10, p. 999-1010

Understandinghowtraits are integrated at the organismal level remains a fundamental problem at the interface of developmental and evolutionary biology. Hormones, regulatory signaling molecules that coordinate multiple developmental and physiological processes, are major determinants underlying phenotypic integration. The probably best example for this is the lipid-like juvenile hormone (JH) in...

Université de Fribourg

Ecdysone triggered PGRP‐LC expression controls Drosophila innate immunity

Rus, Florentina ; Flatt, Thomas ; Tong, Mei ; Aggarwal, Kamna ; Okuda, Kendi ; Kleino, Anni ; Yates, Elisabeth ; Tatar, Marc ; Silverman, Neal

In: The EMBO Journal, 2013, vol. 32, no. 11, p. 1626–1638

Throughout the animal kingdom, steroid hormones have been implicated in the defense against microbial infection, but how these systemic signals control immunity is unclear. Here, we show that the steroid hormone ecdysone controls the expression of the pattern recognition receptor PGRP‐LC in Drosophila, thereby tightly regulating innate immune recognition and defense against bacterial...