Intrinsic and Extrinsic Regulation of Hematopoiesis in Drosophila

Abstract

Drosophila melanogaster lymph gland, the primary site of hematopoiesis, contains myeloid-like progenitor cells that differentiate into functional hemocytes in the circulation of pupae and adults. Fly hemocytes are dynamic and plastic, and they play diverse roles in the innate immune response and wound healing. Various hematopoietic regulators in the lymph gland ensure the developmental and functional balance between progenitors and mature blood cells. In addition, systemic factors, such as nutrient availability and sensory inputs, integrate environmental variabilities to synchronize the blood development in the lymph gland with larval growth, physiology, and immunity. This review examines the intrinsic and extrinsic factors determining the progenitor states during hemocyte development in the lymph gland and provides new insights for further studies that may extend the frontier of our collective knowledge on hematopoiesis and innate immunity.

Transcription factor expression landscape in Drosophila embryonic cell lines

“…In our RNA-seq data, we detect very high levels of the GATA-like prohemocyte marker serpent ( srp ) in Kc and S2 cells (Table S 5 ). In addition, both cell types express the Friend of GATA homolog u-shaped (ush) , which regulates the population size of crystal cells and can act as an inhibitor of crystal cell differentiation [ 19 ], and scalloped ( sd ), which promotes crystal cell specification in a Notch/Serrate -dependent manner [ 20 ]. This discrepancy could in part be due to the detection sensitivity in our current study, although the level of expression we detect for these two genes is very high.…”

“…This discrepancy could in part be due to the detection sensitivity in our current study, although the level of expression we detect for these two genes is very high. The differentiating prohemocyte markers glial cells missing ( gcm ) and gcm2 are not expressed in either cell type (Table S 5 ), indicating that neither cell line has the molecular profile of an intermediate prohemocyte [ 20 ]. S2 cells do express a detectable level of the Runt domain TF lozenge ( lz ) and pebbled ( pb ), both of which are associated with Notch -dependent crystal cell differentiation and not with plasmatocytes [ 20 – 22 ].…”

“…The differentiating prohemocyte markers glial cells missing ( gcm ) and gcm2 are not expressed in either cell type (Table S 5 ), indicating that neither cell line has the molecular profile of an intermediate prohemocyte [ 20 ]. S2 cells do express a detectable level of the Runt domain TF lozenge ( lz ) and pebbled ( pb ), both of which are associated with Notch -dependent crystal cell differentiation and not with plasmatocytes [ 20 – 22 ]. Expression of these two crystal cell markers is very low in Kc cells (Table S 5 ).…”

“…Expression of these two crystal cell markers is very low in Kc cells (Table S 5 ). Intriguingly, klumpfuss ( klu ), which has been shown to inhibit pre-destined crystal cells from becoming plasmatocytes [ 20 ], is expressed at a higher level in Kc cells than S2 cells.…”

Drosophila Gut Immune Pathway Suppresses Host Development-Promoting Effects of Acetic Acid Bacteria

“…The Drosophila immune system is composed of the immune deficiency (IMD) pathway and the Toll pathway as well as hemocyte activity ( Buchon et al, 2014 ; Koranteng et al, 2022 ). First, we investigated the effects of IMD immune activity on larval development stimulated by Ap mono-association.…”