Circadian regulation of immune system function is poorly understood but has significant impact on human health. Many measures of immune system function, such as baseline levels of the cytokines TNF and IFN- gamma, vary with time of day. Loss of circadian regulation is also associated with poor immune system function and susceptibility to infection. We have established a system to study circadian-regulated immune function in Drosophila. We found that flies infected at different times of day with S. pneumoniae die with different survival rates and that this is due to the effects of circadian regulatory protens. We further identified a specific immune response that is circadian-regulated: phagocytosis of bacteria. Though the cell biology of phagocytosis is well studied in unicellular organisms and in cultured cells, the molecular regulation of phagocytosis in multicellular organisms is less clear. Similarly, though much is known about circadian regulation, the major focus has been on molecular mechanisms and circadian regulatory neurons (pacemaker neurons)-not on effectors tissues. We need to understand the circadian regulation of relevant effectors tissues to translate these discoveries into medical practice. In preliminary data, we found that inhibition of the circadian regulator Clock in either pacemaker neurons or phagocytic immune cells increases resistance to infection by S. pneumoniae. We hypothesize that pacemaker neurons regulate the circadian rhythms of phagocytic immune cells, dictating the oscillation of Clock activity in those cells as well as phagocytic activity. In this proposal, we will test this hypothesis in three ways: we will identify cellular mechanisms underlying circadian-regulated phagocytosis (Aim 1);we will also examine how cell-autonomous circadian regulators control phagocyte function (Aim 2) and how pacemaker neurons non cell-autonomously regulate phagocyte function (Aim 3). Thus the proposed experiments will analyze circadian regulation of immune system function on molecular, cellular, and systemic levels. Because of the high evolutionary conservation of both innate immunity and circadian biology, defining the molecular mechanisms in Drosophila will provide insight into ways to improve human innate immune system function.

Public Health Relevance

Phagocytosis of bacteria by immune blood cells is a highly conserved and crucial innate immune response to infection in both flies and vertebrates;people with defects in phagocytic immune cells typically have severe, recurring bacterial infections. We found that phagocytosis is a circadian-regulated immune response in Drosophila, a genetically tractable model organism. This project investigates the cellular and molecular mechanisms underlying circadian regulation of phagocytosis with the long-term goal of identifying molecular targets to manipulate phagocyte function in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM105775-02S1
Application #
8914862
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Dunsmore, Sarah
Project Start
2013-05-01
Project End
2018-01-31
Budget Start
2014-02-01
Budget End
2015-01-31
Support Year
2
Fiscal Year
2014
Total Cost
$71,365
Indirect Cost
$5,082
Name
Columbia University (N.Y.)
Department
Genetics
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
Qiao, Bing; Li, Chiyuan; Allen, Victoria W et al. (2018) Automated analysis of long-term grooming behavior in Drosophila using a k-nearest neighbors classifier. Elife 7:
Salazar, Anna M; Resnik-Docampo, Martin; Ulgherait, Matthew et al. (2018) Intestinal Snakeskin Limits Microbial Dysbiosis during Aging and Promotes Longevity. iScience 9:229-243
Hirsch, Sophia M; Sundaramoorthy, Sriramkumar; Davies, Tim et al. (2018) FLIRT: fast local infrared thermogenetics for subcellular control of protein function. Nat Methods 15:921-923
Davies, Tim; Kim, Han X; Romano Spica, Natalia et al. (2018) Cell-intrinsic and -extrinsic mechanisms promote cell-type-specific cytokinetic diversity. Elife 7:
O'Connor, Reed M; Stone, Elizabeth F; Wayne, Charlotte R et al. (2017) A Drosophila model of Fragile X syndrome exhibits defects in phagocytosis by innate immune cells. J Cell Biol 216:595-605
Davies, T; Sundaramoorthy, S; Jordan, S N et al. (2017) Using fast-acting temperature-sensitive mutants to study cell division in Caenorhabditis elegans. Methods Cell Biol 137:283-306
Zhuravlev, Yelena; Hirsch, Sophia M; Jordan, Shawn N et al. (2017) CYK-4 regulates Rac, but not Rho, during cytokinesis. Mol Biol Cell 28:1258-1270
Sundaramoorthy, Sriramkumar; Garcia Badaracco, Adrian; Hirsch, Sophia M et al. (2017) Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope. ACS Appl Mater Interfaces 9:7929-7940
Allen, Victoria W; O'Connor, Reed M; Ulgherait, Matthew et al. (2016) period-Regulated Feeding Behavior and TOR Signaling Modulate Survival of Infection. Curr Biol 26:184-194
Jordan, Shawn N; Davies, Tim; Zhuravlev, Yelena et al. (2016) Cortical PAR polarity proteins promote robust cytokinesis during asymmetric cell division. J Cell Biol 212:39-49

Showing the most recent 10 out of 13 publications