Name: methods to examine the lymph gland and hemocytes in drosophila larvae
Uploaded: 2016-11-28T14:00:00
Description: Watch this Scientific Journal Video about Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae at JoVE.com

We thank Matthew O'Connell, Maryam Jahanshahi, and Andreas Jenny for assistance. We thank Istv&#225;n And&#243; for plasmatocyte-specific antibodies, Utpal Banerjee for dome-meso-EBFP2 flies, Julian Martinez-Agosto for antp&gt;GFP flies, and Michael O'Connor for ptth and ptth&gt;grim flies. These methods were developed with support by the Kimmel Foundation, the Leukemia &amp; Lymphoma Society, NIH/NCI R01CA140451, NSF 1257939, DOD/NFRP W81XWH-14-1-0059, and NIH/NCI T32CA078207.

1. Circulating Hemocyte Concentration
<ol>
	<li>To obtain larvae of roughly the same developmental stage for this assay, restrict egg collection by allowing females to lay eggs for a fixed time period of 2 - 6 hr.</li>
	<li>Collect larvae in dissecting dish wells filled with 1x phosphate buffered saline (PBS, Table 1).</li>
	<li>For each larva, place 10 &#181;l 1x PBS in a microcentrifuge tube on ice and 10 &#181;l 1x PBS on a clean dissecting pad. Place the dissecting pad on an illuminated stereomicro...

<ol>
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J., Hartenstein, V., Banerjee, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Hedgehog-+and+Antennapedia-dependent+niche+maintains+Drosophila+haematopoietic+precursors.">A Hedgehog- and Antennapedia-dependent niche maintains Drosophila haematopoietic precursors.</a> Nature. 446 (7133), 320-324 (2007).</li><li>Benmimoun, B., Polesello, C., Haenlin, M., Waltzer, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+EBF+transcription+factor+Collier+directly+promotes+Drosophila+blood+cell+progenitor+maintenance+independently+of+the+niche.">The EBF transcription factor Collier directly promotes Drosophila blood cell progenitor maintenance independently of the niche.</a> Proc Natl Acad Sci U S A. 112 (29), 9052-9057 (2015).</li><li>Sinenko, S. A., Mandal, L., Martinez-Agosto, J. A., Banerjee, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+role+of+wingless+signaling+in+stem-like+hematopoietic+precursor+maintenance+in+Drosophila.">Dual role of wingless signaling in stem-like hematopoietic precursor maintenance in Drosophila.</a> Dev Cell. 16 (5), 756-763 (2009).</li><li>Pennetier, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+control+of+the+Drosophila+hematopoietic+niche+by+bone+morphogenetic+protein+signaling+reveals+parallels+with+mammals.">Size control of the Drosophila hematopoietic niche by bone morphogenetic protein signaling reveals parallels with mammals.</a> Proc Natl Acad Sci U S A. 109 (9), 3389-3394 (2012).</li><li>Dragojlovic-Munther, M., Martinez-Agosto, J. 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Upon genetic or environmental alteration, the four methods described here can be used individually or in conjunction to analyze distinct processes during hematopoiesis such as signaling, survival, proliferation, and differentiation. Drosophila hematopoiesis is a dynamic process; the number of hemocytes per animal increases35 and the structure and gene expression of the lymph gland changes32 during development. Prior to performing these assays, therefore, it is critical to restrict egg colle...

The complex mechanisms regulating the transcription factors and signaling pathways that coordinate the development of the hematopoietic system and that malfunction in hematological diseases remain poorly understood. These transcription factors and signaling pathways, as well as their regulation, are highly conserved between Drosophila and mammalian hematopoiesis1-5. Thus the Drosophila hematopoietic system represents an excellent genetic model to define the molecular mechanisms controlling hematopoiesis and underlying hematological diseases.
Similar to mammals, Drosophila generate blood cells, called hemocytes, in spatially and temporally distinct phases of hematopoiesis. Traditionally, Drosophila hematopoiesis was thought to be restricted to phases in the embryonic mesoderm and in the larval lymph gland. Recent studies provide evidence that hematopoiesis also occurs in larval sessile clusters and in the adult abdomen6-8. All hematopoietic phases produce two types of mature hemocytes: plasmatocytes and crystal cells. Plasmatocytes are macrophage-like cells involved in phagocytosis, innate immunity, and wound healing. Crystal cells contain pro-phenoloxidases required for melanization, a reaction used in insect immune responses and wound healing. Larval hematopoiesis can generate a third mature hemocyte type, called a lamellocyte, in response to certain immune challenges such as parasitoid wasp infection9,10. Lamellocytes are large, adherent cells that function, in conjunction with plasmatocytes and crystal cells, to encapsulate and neutralize wasp eggs laid in Drosophila larvae. In the absence of parasitization, lamellocytes are not found in wild-type larvae. Melanotic masses resemble melanized, encapsulated wasp eggs; many mutant Drosophila strains develop melanotic masses in the absence of parasitization. The presence of lamellocytes and/or melanotic masses can be indicative of hematopoietic abnormalities. In fact, the melanotic mass phenotype has been used to identify genes and pathways involved in hematopoiesis11-14.
The larval hematopoietic system is the most extensively studied to date. It is comprised of hemocytes circulating in the hemolymph, sessile hemocyte clusters patterned under the cuticle, and hemocytes residing in the lymph gland. The lymph gland is a series of bilateral lobes attached to the dorsal vessel. Each primary lobe of the lymph gland is divided into three main zones. The outermost zone is known as the cortical zone and contains maturing hemocytes. The innermost zone is called the medullary zone and is comprised of quiescent hemocyte precursors. The third zone, the posterior signaling center, is a small group of cells at the base of the lymph gland that act as a stem cell-like niche. Early work established critical functions for Notch15-18, Hedgehog19,20, JAK-STAT18, and Wingless21 activity to regulate larval lymph gland development. More recent studies have demonstrated that BMP22, FGF-Ras23, and Hippo24,25 signaling also function within the larval lymph gland.
Four larval hematopoietic assays outlined here describe 1) measuring circulating hemocyte concentration, defined as number of cells per unit volume, 2) isolating and fixing circulating hemocytes for immunohistochemistry, 3) visualizing crystal cells in vivo, and 4) dissecting, fixing, and mounting lymph glands for immunohistochemistry. These assays can be used as hematopoietic readouts to assess the functions and regulations of signaling pathways in the larval hematopoietic system. While these methods have been used previously in the field, visual documentation of these assays has begun only recently8,26-30. Several publications cited here are helpful resources describing similar methods and hematopoietic markers26,31-33. Additionally, Trol and Viking are useful markers of the lymph gland basement membrane.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">PBS tablets</td>
			<td style="width:176px;">MP Biomedicals</td>
			<td style="width:163px;">2810305</td>
			<td style="width:236px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">dissecting dish</td>
			<td style="width:176px;">Corning</td>
			<td style="width:163px;">7220-85</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">microcentrifuge tube</td>
			<td style="width:176px;">Denville</td>
			<td style="width:163px;">C2170</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:229px;">silicone dissecting pad, made from Sylgard 184 kit</td>
			<td style="width:176px;">Krayden (distributed through Fisher)</td>
			<td style="width:163px;">NC9644388 (Fisher catalog number)</td>
			<td style="width:236px;">Made in petri dish by mixing components of Sylgard elastomer kit according to manufacturer instructions.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">stereomicroscope</td>
			<td style="width:176px;">Morrell Instruments (Nikon distributor)</td>
			<td>mna42000, mma36300</td>
			<td>Nikon models SMZ1000 and SMZ645</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">tissue wipe</td>
			<td style="width:176px;">VWR</td>
			<td style="width:163px;">82003-820</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">forceps</td>
			<td style="width:176px;">Electron Microscopy Sciences</td>
			<td style="width:163px;">72700-DZ</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">p200 pipette</td>
			<td style="width:176px;">Eppendorf</td>
			<td>3120000054</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">Countess Automated Cell Counter</td>
			<td style="width:176px;">Invitrogen</td>
			<td style="width:163px;">C10227</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">Countess cell counting chamber slides</td>
			<td style="width:176px;">Invitrogen</td>
			<td style="width:163px;">C10283</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">hemocytometer</td>
			<td style="width:176px;">Hausser Scientific</td>
			<td style="width:163px;">3200</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">trypan blue stain</td>
			<td style="width:176px;">Life Technologies</td>
			<td style="width:163px;">T10282</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">formaldehyde</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">BP531-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Triton</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">BP151-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">Tween 20</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">BP337-500</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">bovine serum albumin</td>
			<td style="width:176px;">Rocky Mountain Biologicals</td>
			<td style="width:163px;">BSA-BSH-01K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">normal goat serum</td>
			<td style="width:176px;">Sigma</td>
			<td style="width:163px;">G9023-10ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">normal donkey serum</td>
			<td style="width:176px;">Sigma</td>
			<td style="width:163px;">D9663-10ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">200 proof ethanol</td>
			<td style="width:176px;">VWR</td>
			<td style="width:163px;">V1001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">N-propyl gallate</td>
			<td style="width:176px;">MP Biomedicals</td>
			<td style="width:163px;">102747</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">glycerol</td>
			<td style="width:176px;">VWR</td>
			<td style="width:163px;">EM-4750</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">DAPI (4&#8217;,6-diamidino-2-phenylindole)</td>
			<td style="width:176px;">Fisher</td>
			<td>62248</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">6-well plate</td>
			<td style="width:176px;">Corning</td>
			<td style="width:163px;">351146</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">12-well plate</td>
			<td style="width:176px;">Corning</td>
			<td style="width:163px;">351143</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">microscope cover glass, 22 mm square</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">12-544-10</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:229px;">microscope cover glass, 18mm circular</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">12-545-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">glass microscope slides</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">22-034-980</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">thermal cycler</td>
			<td style="width:176px;">Eppendorf</td>
			<td>E950010037</td>
			<td>Mastercycler EP Gradient S</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">PCR tubes</td>
			<td style="width:176px;">USA Scientific</td>
			<td style="width:163px;">1402-2700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">24-well plate</td>
			<td style="width:176px;">Corning</td>
			<td style="width:163px;">351147</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">disposable transfer pipet</td>
			<td style="width:176px;">Fisher</td>
			<td style="width:163px;">13-711-9AM</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:229px;">fluorescence microscope</td>
			<td style="width:176px;">Zeiss</td>
			<td style="width:163px;"></td>
			<td>Axio Imager.Z1</td>
		</tr>
	</tbody>
</table>

methods to examine the lymph gland and hemocytes in drosophila larvae

Many parallels exist between the Drosophila and mammalian hematopoietic systems, even though Drosophila lack the lymphoid lineage that characterize mammalian adaptive immunity. Drosophila and mammalian hematopoiesis occur in spatially and temporally distinct phases to produce several blood cell lineages. Both systems maintain reservoirs of blood cell progenitors with which to expand or replace mature lineages. The hematopoietic system allows Drosophila and mammals to respond to and to adapt to immune challenges. Importantly, the transcriptional regulators and signaling pathways that control the generation, maintenance, and function of the hematopoietic system are conserved from flies to mammals. These similarities allow Drosophila to be used to genetically model hematopoietic development and disease.
Here we detail assays to examine the hematopoietic system of Drosophila larvae. In particular, we outline methods to measure blood cell numbers and concentration, visualize a specific mature lineage in vivo, and perform immunohistochemistry on blood cells in circulation and in the hematopoietic organ. These assays can reveal changes in gene expression and cellular processes including signaling, survival, proliferation, and differentiation and can be used to investigate a variety of questions concerning hematopoiesis. Combined with the genetic tools available in Drosophila, these assays can be used to evaluate the hematopoietic system upon defined genetic alterations. While not specifically outlined here, these assays can also be used to examine the effect of environmental alterations, such as infection or diet, on the hematopoietic system.

Circulating Hemocyte Concentration
Hemocyte numbers increase throughout larval development35. To illustrate that this method detects differences in hemocyte numbers and concentration, regardless of the biological cause, we measured hemocyte concentrations of delayed and non-delayed larvae. Loss of prothoracicotropic hormone (ptth) by genetic ablation of ptth-producing neurons (ptth&#62;grim) produces a delay in larval de...

Watch this Scientific Journal Video about Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae at JoVE.com

Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae

Drosophila and mammalian hematopoietic systems share many common features, making Drosophila an attractive genetic model to study hematopoiesis. Here we demonstrate dissection and mounting of the major larval hematopoietic organ for immunohistochemistry. We also describe methods to assay various larval hematopoietic compartments including circulating hemocytes and sessile crystal cells.

Methods to Examine the Lymph Gland and Hemocytes in Drosophila Larvae

Many parallels exist between the Drosophila and mammalian hematopoietic systems, even though Drosophila lack the lymphoid lineage that characterize ...

Research

JoVE Journal

Developmental Biology

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the ...

Methods for Imaging Intracellular pH of the Follicle Stem Cell Lineage in Live Drosophila Ovarian Tissue

Methods for Imaging Intracellular pH of the Follicle Stem Cell Lineage in Live Drosophila Ovarian Tissue

Changes in intracellular pH (pHi) play important roles in the regulation of many cellular functions, including metabolism, proliferation, and ...

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Notch signaling is an evolutionarily conserved cell-cell communication system used broadly in animal development and adult maintenance. Interaction of the ...

Methods for the Study of Regeneration in Stentor

Methods for the Study of Regeneration in Stentor

Cells need to be able to regenerate their parts to recover from external perturbations. The unicellular ciliate Stentor coeruleus is an excellent model ...

Thawing, Culturing, and Cryopreserving Drosophila Cell Lines

Thawing, Culturing, and Cryopreserving Drosophila Cell Lines

There are currently over 160 distinct Drosophila cell lines distributed by the Drosophila Genomics Resource Center (DGRC). With genome engineering, the ...

Methods to Test Endocrine Disruption in Drosophila melanogaster

Methods to Test Endocrine Disruption in Drosophila melanogaster

In recent years there has been growing evidence that all organisms and the environment are exposed to hormone-like chemicals, known as endocrine disruptor ...

Whole Mount Immunohistochemistry in Zebrafish Embryos and Larvae

Immunohistochemistry is a widely used technique to explore protein expression and localization during both normal developmental and disease states. ...

Using Alizarin Red Staining to Detect Chemically Induced Bone Loss in Zebrafish Larvae

Chemically induced bone loss due to lead (Pb) exposure could trigger an array of adverse impacts on both human and animal skeletal systems. However, the ...

Eye Removal in Living Zebrafish Larvae to Examine Innervation-dependent Growth and Development of the Visual System

Zebrafish exhibit remarkable life-long growth and regenerative abilities. For example, specialized stem cell niches established during embryogenesis ...