Macrophages and cellular immunity in Drosophila melanogaster

Abstract

The invertebrate Drosophila melanogaster has been a powerful model for understanding blood cell development and immunity. Drosophila is a holometabolous insect, which transitions through a series of life stages from embryo, larva and pupa to adulthood. In spite of this, remarkable parallels exist between Drosophila and vertebrate macrophages, both in terms of development and function. More than 90% of Drosophila blood cells (hemocytes) are macrophages (plasmatocytes), making this highly tractable genetic system attractive for studying a variety of questions in macrophage biology. In vertebrates, recent findings revealed that macrophages have two independent origins: self-renewing macrophages, which reside and proliferate in local microenvironments in a variety of tissues, and macrophages of the monocyte lineage, which derive from hematopoietic stem or progenitor cells. Like vertebrates, Drosophila possesses two macrophage lineages with a conserved dual ontogeny. These parallels allow us to take advantage of the Drosophila model when investigating macrophage lineage specification, maintenance and amplification, and the induction of macrophages and their progenitors by local microenvironments and systemic cues. Beyond macrophage development, Drosophila further serves as a paradigm for understanding the mechanisms underlying macrophage function and cellular immunity in infection, tissue homeostasis and cancer, throughout development and adult life.

Drosophila glia: Few cell types and many conserved functions

“…In line with this assumption is the finding that the BTB/POZ transcription factor Tramtrack is required to suppress neuronal differentiation genes in glial and tracheal cells within the nervous system (Badenhorst, ; Giesen et al, ; Yuasa et al, ). Importantly, the function of the transcriptional activator Gcm is not restricted to glial cells but is also required for the development of the embryonic hematopoetic cell lineage and only the latter appears conserved throughout evolution (Bernardoni, Vivancos, & Giangrande, ; C. J. Evans, Hartenstein, & Banerjee, ; Gold & Brückner, ).…”

“…Importantly, the function of the transcriptional activator Gcm is not restricted to glial cells but is also required for the development of the embryonic hematopoetic cell lineage and only the latter appears conserved throughout evolution (Bernardoni, Vivancos, & Giangrande, 1997;C. J. Evans, Hartenstein, & Banerjee, 2003;Gold & Brückner, 2015).…”

A single-cell survey ofDrosophilablood

“…PMs are macrophage-like cells with parallels to vertebrate tissue macrophages, while CCs and LMs perform functions analogous to clotting and granuloma formation in vertebrates (Buchon et al, 2014). Hemocytes in the larva derive from two lineages: the lymph gland and the embryonic lineage, which in the larva forms resident (sessile) clusters of hemocytes in subepidermal locations, also known as hematopoietic pockets (Gold and Brückner, 2015;Holz et al, 2003;Jung, 2005;Makhijani et al, 2011). Prohemocytes can give rise to all mature hemocytes in the lymph gland (Banerjee et al, 2019).…”

“…Prohemocytes can give rise to all mature hemocytes in the lymph gland (Banerjee et al, 2019). Likewise, the embryonic lineage, which consists of selfrenewing PMs, is capable of producing CCs and LMs during inflammatory conditions (Gold and Brückner, 2015;Leitão and Sucena, 2015;Márkus et al, 2009). Whereas PMs are important for phagocytosis and represent ~90-95% of total hemocytes, CCs, which constitute ~5%, are required for wound healing and melanization (Banerjee et al, 2019;Evans et al, 2003).…”

Transcriptome analysis of the Molecular Mechanism underlying Immunity- and Reproduction trade-off in Locusta migratoria Infected by Micrococcus luteus

“…Primer 5.0 was used to identify appropriate primers (Sup Table 1), and the expression levels of the selected genes were normalized using the expression of actin. Quantitative real-time PCR (qRT-PCR) was performed using a Bio-Rad CFX96 Real-Time PCR Detection system (Bio-Rad, CA, USA) 8 and Premix Ex Taq (SYBR Green) reagents (Takara, Dalian, China). The 20-μl qRT-PCR reactions were subject to a thermal profile of 95 °C for 3 min and then 40 cycles of 95 °C for 10 s and 60 °C for 30 s. The thermal melting profile was assessed using a final PCR cycle of 95 °C for 30 s, with temperature increasing constantly from 60 to 95 °C.…”