Name: myeloid innate signaling pathway regulation by malt1 paracaspase activity
Uploaded: 2019-01-07T14:00:00
Description: Watch this Scientific Journal Video about Myeloid Innate Signaling Pathway Regulation by MALT1 Paracaspase Activity at JoVE.com

We thank Elsevier for their authorization (license number 4334770630127) to reproduce here Figure 2A from Unterreiner et al. (2017).

Experiments were conducted according to the guidelines and standards of the Novartis Human Research Ethics Committee.
1. Preparation of Peripheral Blood Mononuclear Cells (PBMCs) from Human Buffy Coats
NOTE: We received buffy coats from healthy volunteers one day after collection, in 50 mL bags. They were provided under informed consent and collected through the Interregionale Blutspende Schweizeriches Rotes Kreuz. We handled them using the p...

<ol>
	<li>Coornaert, B., 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=T+cell+antigen+receptor+stimulation+induces+MALT1+paracaspase-mediated+cleavage+of+the+NF-kappaB+inhibitor+A20.">T cell antigen receptor stimulation induces MALT1 paracaspase-mediated cleavage of the NF-kappaB inhibitor A20.</a> Nature immunology. 9 (3), 263-271 (2008).</li><li>Rebeaud, F., 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=The+proteolytic+activity+of+the+paracaspase+MALT1+is+key+in+T+cell+activation.">The proteolytic activity of the paracaspase MALT1 is key in T cell activation.</a> Nature immunology. 9 (3), 272-281 (2008).</li><li>Jaworski, M., Thome, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+paracaspase+MALT1:+Biological+function+and+potential+for+therapeutic+inhibition.">The paracaspase MALT1: Biological function and potential for therapeutic inhibition.</a> Cellular and Molecular Life Sciences. 73 (3), 459-473 (2016).</li><li>Meininger, I., Krappmann, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lymphocyte+signaling+and+activation+by+the+CARMA1-BCL10-MALT1+signalosome.">Lymphocyte signaling and activation by the CARMA1-BCL10-MALT1 signalosome.</a> Biological Chemistry. 397 (12), 1315-1333 (2016).</li><li>Qiao, Q., 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=Structural+architecture+of+the+CARMA1/Bcl10/MALT1+signalosome:+nucleation-induced+filamentous+assembly.">Structural architecture of the CARMA1/Bcl10/MALT1 signalosome: nucleation-induced filamentous assembly.</a> Molecular cell. 51 (6), 766-779 (2013).</li><li>Gross, O., 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=Card9+controls+a+non-TLR+signalling+pathway+for+innate+anti-fungal+immunity.">Card9 controls a non-TLR signalling pathway for innate anti-fungal immunity.</a> Nature. 442 (7103), 651-656 (2006).</li><li>Chiffoleau, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=C-type+lectin-like+receptors+as+emerging+orchestrators+of+sterile+inflammation+represent+potential+therapeutic+targets.">C-type lectin-like receptors as emerging orchestrators of sterile inflammation represent potential therapeutic targets.</a> Frontiers in Immunology. 9 (FEB), 1-9 (2018).</li><li>Taylor, P. R., 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=Dectin-1+is+required+for+beta-glucan+recognition+and+control+of+fungal+infection.">Dectin-1 is required for beta-glucan recognition and control of fungal infection.</a> Nature Immunology. 8 (1), 31-38 (2007).</li><li>Lanternier, F., 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=Primary+immunodeficiencies+underlying+fungal+infections.">Primary immunodeficiencies underlying fungal infections.</a> Current opinion in pediatrics. 25 (6), 736-747 (2013).</li><li>Thome, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multifunctional+roles+for+MALT1+in+T-cell+activation.">Multifunctional roles for MALT1 in T-cell activation.</a> Nature reviews. Immunology. 8 (7), 495-500 (2008).</li><li>Unterreiner, A., Stoehr, N., Huppertz, C., Calzascia, T., Farady, C. J., Bornancin, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+MALT1+paracaspase+inhibition+does+not+block+TNF-&#945;+production+downstream+of+TLR-4+in+myeloid+cells.">Selective MALT1 paracaspase inhibition does not block TNF-&#945; production downstream of TLR-4 in myeloid cells.</a> Immunology Letters. , 48-51 (2017).</li><li>Strasser, 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=Syk+Kinase-Coupled+C-type+Lectin+Receptors+Engage+Protein+Kinase+C-&#x3B4;+to+Elicit+Card9+Adaptor-Mediated+Innate+Immunity.">Syk Kinase-Coupled C-type Lectin Receptors Engage Protein Kinase C-&#x3B4; to Elicit Card9 Adaptor-Mediated Innate Immunity.</a> Immunity. 36 (1), 32-42 (2012).</li><li>Jaworski, M., 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=Malt1+protease+inactivation+efficiently+dampens+immune+responses+but+causes+spontaneous+autoimmunity.">Malt1 protease inactivation efficiently dampens immune responses but causes spontaneous autoimmunity.</a> The EMBO journal. 33 (23), 2765-2781 (2014).</li><li>Yu, J. W., 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=MALT1+protease+activity+is+required+for+innate+and+adaptive+immune+responses.">MALT1 protease activity is required for innate and adaptive immune responses.</a> PLoS ONE. 10 (5), 1-20 (2015).</li><li>Bardet, M., 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=The+T-cell+fingerprint+of+MALT1+paracaspase+revealed+by+selective+inhibition.">The T-cell fingerprint of MALT1 paracaspase revealed by selective inhibition.</a> Immunology and Cell Biology. 96 (1), 81-99 (2018).</li><li>Thoma, G., 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=Discovery+and+profiling+of+a+selective+and+efficacious+syk+inhibitor.">Discovery and profiling of a selective and efficacious syk inhibitor.</a> Journal of Medicinal Chemistry. 58 (4), 1950-1963 (2015).</li><li>Bauer, B., Steinle, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HemITAM:+A+single+tyrosine+motif+that+packs+a+punch.">HemITAM: A single tyrosine motif that packs a punch.</a> Science Signaling. 10 (508), 1-10 (2017).</li><li>Gringhuis, S. I., 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=Selective+c-Rel+activation+via+Malt1+controls+anti-fungal+TH-17+immunity+by+dectin-1+and+dectin-2.">Selective c-Rel activation via Malt1 controls anti-fungal TH-17 immunity by dectin-1 and dectin-2.</a> PLoS Pathogens. 7 (1), (2011).</li><li>Dufner, A., Schamel, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=B+cell+antigen+receptor-induced+activation+of+an+IRAK4-dependent+signaling+pathway+revealed+by+a+MALT1-IRAK4+double+knockout+mouse+model.">B cell antigen receptor-induced activation of an IRAK4-dependent signaling pathway revealed by a MALT1-IRAK4 double knockout mouse model.</a> Cell Communication and Signaling. 9 (1), 6 (2011).</li><li>Phelan, J. 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=A+multiprotein+supercomplex+controlling+oncogenic+signalling+in+lymphoma.">A multiprotein supercomplex controlling oncogenic signalling in lymphoma.</a> Nature. , (2018).</li></ol>

In this work, we used simple experimental settings to study signaling pathways in human and mouse innate cells, and interrogate their dependency on MALT1 proteolytic function. Expanding on previous work11, our study showed that MALT1 paracaspase activity controls C-type lectin-like receptor induced cytokine production, including TNF-&#945;. In contrast, TLR-4-induced TNF-&#945; was independent of MALT1 in both species. Collectively, these data corroborated the key and selective contribution of the...

The paracaspase activity of MALT1 (Mucosa-associated lymphoid tissue lymphoma translocation protein 1) was revealed in 20081,2. Since then, a number of studies have reported its critical contribution to antigen receptor responses in lymphocytes. Genetic models in the mouse as well as pharmacology data support a key role in T cells, in T-cell dependent autoimmunity and in B-cell lymphoma settings3,4. In lymphocytes, MALT1 paracaspase activation occurs upon assembly of a CARD11-BCL10-MALT1 complex5, which is triggered by antigen-receptor proximal signaling downstream of the T- or B- cell receptor. There is also ample evidence that a similar CARD9-BCL10-MALT1 complex is important for propagating signals downstream of C-type lectin-like receptors (CLLR), e.g., Dectin-1, Dectin-2 and MINCLE in myeloid cells6,7. Dectin-1 has been particularly well studied because this pathway is critical for host defense against fungal infections8,9. Implication of MALT1 in Toll-like receptor (TLR) pathways, however, has remained controversial10. Recent evidence in human myeloid cells ruled out a direct role for MALT1 paracaspase activity in the regulation of TNF- production downstream of TLR-411.
In the present work, we used various experimental settings and stimulatory conditions in human and mouse myeloid cells to probe innate signaling pathways, relying on specific pharmacological tool inhibitors and measurement of cytokine production.

<table>
	<tbody>
		<tr>
			<td>100 &#181;m nylon cell strainer</td>
			<td>Sigma</td>
			<td>CLS431752</td>
			<td></td>
		</tr>
		<tr>
			<td>14 ml Falcon tube</td>
			<td>BD Falcon</td>
			<td>352057</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL Falcon tube</td>
			<td>Falcon</td>
			<td>352090</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Falcon tube</td>
			<td>Falcon</td>
			<td>352070</td>
			<td></td>
		</tr>
		<tr>
			<td>6 well plates</td>
			<td>Costar</td>
			<td>3516</td>
			<td></td>
		</tr>
		<tr>
			<td>96 well flat-bottom plate, with low evaporation lid</td>
			<td>Costar</td>
			<td>3595</td>
			<td></td>
		</tr>
		<tr>
			<td>96 well V-bottom plate</td>
			<td>Costar</td>
			<td>734-1798</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium Chloride - NH4Cl</td>
			<td>Sigma</td>
			<td>A9434</td>
			<td></td>
		</tr>
		<tr>
			<td>Assay diluent RD1-W ELISA</td>
			<td>R&#38;D</td>
			<td>895038</td>
			<td>Assay diluent</td>
		</tr>
		<tr>
			<td>Cell culture microplate, 384 well, black</td>
			<td>Greiner</td>
			<td>781986</td>
			<td></td>
		</tr>
		<tr>
			<td>Depleted Zymosan</td>
			<td>Invivogen</td>
			<td>tlrl-dzn</td>
			<td>now: tlrl-zyd</td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide</td>
			<td>Sigma</td>
			<td>D2650</td>
			<td>DMSO</td>
		</tr>
		<tr>
			<td>EDTA-Na2</td>
			<td>Sigma</td>
			<td>E5134</td>
			<td>Ethylenediaminetetraacetic acid disodium salt dihydrate</td>
		</tr>
		<tr>
			<td>ELISA muTNF-&#945;</td>
			<td>R&#38;D</td>
			<td>SMTA00</td>
			<td></td>
		</tr>
		<tr>
			<td>Ficoll-Paque Plus</td>
			<td>GE Healthcare</td>
			<td>17-1440-03</td>
			<td></td>
		</tr>
		<tr>
			<td>gentleMACS C tubes</td>
			<td>MACS Miltenyi Biotec</td>
			<td>130-096-334</td>
			<td></td>
		</tr>
		<tr>
			<td>gentleMACS dissociator</td>
			<td>MACS Miltenyi Biotec</td>
			<td>130-093-235</td>
			<td></td>
		</tr>
		<tr>
			<td>GM-CSF</td>
			<td>Novartis</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Heat-inactivated Fetal bovine serum</td>
			<td>Gibco</td>
			<td>10082</td>
			<td>FBS</td>
		</tr>
		<tr>
			<td>HTRF hu IL-23</td>
			<td>CisBio</td>
			<td>62HIL23PEG</td>
			<td></td>
		</tr>
		<tr>
			<td>HTRF hu TNF-&#945;</td>
			<td>CisBio</td>
			<td>62TNFPEC</td>
			<td></td>
		</tr>
		<tr>
			<td>HTRF reconstitution buffer</td>
			<td>CisBio</td>
			<td>62RB3RDE</td>
			<td>50mM Phosphate buffer, pH 7.0, 0.8M KF, 0.2% BSA</td>
		</tr>
		<tr>
			<td>IFN-&#947;</td>
			<td>R&#38;D</td>
			<td>L4516</td>
			<td></td>
		</tr>
		<tr>
			<td>IL-4</td>
			<td>Novartis</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Abbott</td>
			<td>Forene</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipopolysaccharides (LPS)</td>
			<td>Sigma</td>
			<td>L4391</td>
			<td>LPS used in human samples</td>
		</tr>
		<tr>
			<td>Lipopolysaccharides</td>
			<td>Sigma</td>
			<td>L4516</td>
			<td>LPS used in murine samples</td>
		</tr>
		<tr>
			<td>Lysis buffer</td>
			<td>Self-made</td>
			<td>-</td>
			<td>155 mM NH4Cl, 10 mM KHCO3, 1 mM EDTA, pH 7.4</td>
		</tr>
		<tr>
			<td>Magnet</td>
			<td>Stemcell</td>
			<td>18001</td>
			<td></td>
		</tr>
		<tr>
			<td>Microplate, 384 well white</td>
			<td>Greiner</td>
			<td>784075</td>
			<td></td>
		</tr>
		<tr>
			<td>Monocytes enrichment kit</td>
			<td>Stemcell</td>
			<td>19059</td>
			<td></td>
		</tr>
		<tr>
			<td>Nalgene Mr. Frosty Cryo 1 &#176;C Freezing Container</td>
			<td>Nalgene</td>
			<td>5100-0001</td>
			<td>cooling device (containing Propanol-2)</td>
		</tr>
		<tr>
			<td>PBS 1x pH 7.4 [-] CaCl2 [-] MgCl2</td>
			<td>Gibco</td>
			<td>10010</td>
			<td>Phosphate-buffered saline</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Gibco</td>
			<td>15140</td>
			<td>Pen/Strep</td>
		</tr>
		<tr>
			<td>Potassium bicarbonate - KHCO3</td>
			<td>Sigma</td>
			<td>P9144</td>
			<td></td>
		</tr>
		<tr>
			<td>PrestoBlue</td>
			<td>Invitrogen</td>
			<td>A13262</td>
			<td>Resazurin solution for viability assessment</td>
		</tr>
		<tr>
			<td>Propanol-2</td>
			<td>Merck</td>
			<td>1.09634</td>
			<td></td>
		</tr>
		<tr>
			<td>Read buffer</td>
			<td>MesoScale Discovery</td>
			<td>R92TC-3</td>
			<td>Tris-based buffer containing tripropylamine</td>
		</tr>
		<tr>
			<td>Recovery cell culture freezing medium</td>
			<td>Gibco</td>
			<td>12648-010</td>
			<td>freezing medium</td>
		</tr>
		<tr>
			<td>Roswell Park Memorial Institute Medium (RPMI) with Glutamax</td>
			<td>Gibco</td>
			<td>61870</td>
			<td>+ 10% FBS for iMoDCs 
			+ 10% FBS + 1 mM Sodium Pyruvate + 100 U/mL Pen/Strep + 5 &#181;M &#946;-mercaptoethanol for human PBMCs and monocytes 
			+ 10% FBS + Pen/Strep + 5 &#181;M &#946;-mercaptoethanol for murine splenocytes</td>
		</tr>
		<tr>
			<td>Separation buffer</td>
			<td>Self-made</td>
			<td>-</td>
			<td>PBS pH 7.4 + 2% FBS + 1 mM EDTA pH 8.0</td>
		</tr>
		<tr>
			<td>Sodium Pyruvate</td>
			<td>Gibco</td>
			<td>11360</td>
			<td></td>
		</tr>
		<tr>
			<td>Trehalose-6,6-dibehenate</td>
			<td>Invivogen</td>
			<td>tlrl-tdb</td>
			<td>TDB</td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma</td>
			<td>P7949</td>
			<td>Polysorbate 20</td>
		</tr>
		<tr>
			<td>UltraPure 0.5 M EDTA pH 8.0</td>
			<td>Invitrogen</td>
			<td>15675</td>
			<td>Ethylenediaminetetraacetic acid</td>
		</tr>
		<tr>
			<td>Viewseal sealer</td>
			<td>Greiner BioOne</td>
			<td>676070</td>
			<td></td>
		</tr>
		<tr>
			<td>V-PLEX Proinflammatory Panel 1 Human Kit</td>
			<td>MesoScale Discovery</td>
			<td>K15049D</td>
			<td>electrochemiluminescent multiplex assay (IL-1&#946;, TNF-&#945;, IL-6, IL-8)</td>
		</tr>
		<tr>
			<td>&#946;-Mercaptoethanol</td>
			<td>Gibco</td>
			<td>31350</td>
			<td></td>
		</tr>
	</tbody>
</table>

myeloid innate signaling pathway regulation by malt1 paracaspase activity

Besides its function in lymphoid cells, which has been addressed by numerous studies, the paracaspase MALT1 also plays an important role in innate cells downstream of pattern recognition receptors. Best studied are the Dectin-1 and Dectin-2 members of the C-type lectin-like receptor family that induce a SYK- and CARD9-dependent signaling cascade leading to NF-&#954;B activation, in a MALT1-dependent manner. By contrast, Toll-like receptors (TLR), such as TLR-4, propagate NF-&#954;B activation but signal via an MYD88/IRAK-dependent cascade. Nonetheless, whether MALT1 might contribute to TLR-4 signaling has remained unclear. Recent evidence with MLT-827, a potent and selective inhibitor of MALT1 paracaspase activity, indicates that TNF- production downstream of TLR-4 in human myeloid cells is independent of MALT1, as opposed to TNF- production downstream of Dectin-1, which is MALT1 dependent. Here, we addressed the selective involvement of MALT1 in pattern recognition sensing further, using a variety of human and mouse cellular preparations, and stimulation of Dectin-1, MINCLE or TLR-4 pathways. We also provided additional insights by exploring cytokines beyond TNF-, and by comparing MLT-827 to a SYK inhibitor (Cpd11) and to an IKK inhibitor (AFN700). Collectively, the data provided further evidence for the MALT1-dependency of C-type lectin-like receptor &#8212;signaling by contrast to TLR-signaling.

In myeloid cells, MALT1 relays activation signals downstream of several C-type lectin-like receptors, such as Dectin-1, Dectin-2 and MINCLE6. These pathways rely on (hem)ITAM motif-containing receptors (e.g., Dectin-1) or ITAM motif-containing co-receptors (e.g., FcR&#947;, for Dectin-2 and MINCLE) that recruit and activate the SYK kinase (Figure 1). This leads to activation of a protein kinase C isoform, namely PKC&#...

Watch this Scientific Journal Video about Myeloid Innate Signaling Pathway Regulation by MALT1 Paracaspase Activity at JoVE.com

Myeloid Innate Signaling Pathway Regulation by MALT1 Paracaspase Activity

MALT1 regulates innate immunity but how this occurs remains ill-defined. We used the selective MALT1 paracaspase inhibitor MLT-827 to unravel the contribution of MALT1 to innate signaling downstream of Toll-like or C-type lectin-like receptors, demonstrating that MALT1 regulates the production of myeloid cytokines, and downstream of C-type lectin-like receptors, selectively.

Besides its function in lymphoid cells, which has been addressed by numerous studies, the paracaspase MALT1 also plays an important role in innate cells ...

So the aim of the method in our manuscript is to provide comparative analysis of signaling pathways in myeloid cells using human and mouse systems. It helps define which signaling pathway is involved downstream of selected pattern recognition receptors. So this method is simple to implement.It relies on primary cell preparations and validated reference compounds, which is essential for the elucidation of signaling mechanisms. Demonstrating the procedure will be Ratiba Touil and Adeline Unterreiner, respectively scientist and research associate in our group. In a laminar flow hood set out a sterile pair of scissors, a one liter beaker, and a plastic bag.Place the previously obtained buffy coat into the beaker and use the scissors to carefully open it. Using a 25 mm pipette add 100 ml of PBS supplemented with 2 millimolar of EDTA. Mix by slowly pipetting up and down.And then transfer 25 ml of the diluted buffy coat into six 50 ml conical centrifuge tubes that have each been prefilled with 15 ml of polysaccharide based density gradient. Centrifuge the tubes for 20 minutes at 800 g with moderate acceleration without the break to allow for separation of cells based on their densities. After centrifugation three layers will be visible, a pellet containing red blood cells and granulocytes, an upper layer made of plasma, and a white ring containing peripheral blood mononuclear cells.Use a 10 ml pipette to harvest the PBMC rings and transfer them into a new 50 ml tube. Top up with PBS and EDTA. Perform three successive washes with decreasing centrifugation time and speed as outlined in the text protocol.After the final wash, resuspend the pellet in 25 ml of ice cold lysis buffer to lyse the red blood cells by osmotic pressure. Incubate the solution at room temperature until it becomes clear. Then add 25 ml of separation buffer to stop the reaction.Centrifuge at 150 g for eight minutes to wash the solution. Pour off the supernatant and resuspend the pellet with separation buffer. After counting the cells, dilute them in culture medium down to 12, 500 cells per well.Distribute 30 ml of this cell suspension into each well of a 384 well plate. Next add 15 microliters of four times concentrated compound solutions to each well and preincubate the plate at 37 degrees Celsius with 5%carbon dioxide for one hour. If desired, add either LPS to final concentration of 1 ng per ml or depleted Zymosan to a final concentration of 100 mcg per ml.Then incubate the plate overnight at 37 degrees Celsius with 5%carbon dioxide. The next day take 10 microliters of the supernatant to measure the secreted TNF alpha levels. To begin the serial dilution, dilute the MLT-827 stock solution with medium to reach a concentration of 8 micromolar in one go.Perform a six-step 1:5 serial dilution using medium with 0.08%DMSO. To prepare for single dose testings, dilute the MLT-827, AFN700, and compound 11 stock solutions with medium to reach a concentration of 4 micromolar in one go. First, add 2 ml of sterile endotoxin-free water to 10 mg of depleted Zymosan.Vortex this stock solution to homogenize it. Aliquot the solution and then store the aliquots at 20 degrees Celsius. In this study human PBMCs and mouse spleen cells are stimulated with either depleted Zymosan, a Dectin-1 agonist, or lipopolysaccharide, a TL4 agonist.NTNF alpha release in the supernatant is measured after 20 hours. In both the human and mouse assays the MLT-827 compound selectively blocks TNF alpha production driven by the Dectin-1 pathway but not by the TLR4 pathway. In monocytes stimulated with LPS, production of TNF alpha is almost completely abrogated by AFN700 but it's not sensitive to Cpd11, which is consistent with the TLR4 pathway's dependency on NF-kappa B activity and its independency on SIC activity.In contrast TNF alpha production driven by Dectin-1 and MODCs shows sensitivity to MLT-827, AFN700, and Cpd11. This provides further evidence for the involvement of a SIC CBM signaling cascade in the Dectin-1 pathway. Production of IL-1 beta, IL-6, and IL-23 is also sensitive to the three inhibitors, indicating regulatory mechanisms similar to TNF alpha.However, the limited effect seen on the production of IL-8 suggests that this cytokine has a distinct regulatory mechanism. Raising Trehalose-dibehenate concentrations above 50 mcg per ml leads to production of TNF alpha, IL-6, and IL-1 beta, which relied on MALT1 paracaspase activity according to the blocking effect of MLT-827. Similar results were seen when challenging the MODCs with increasing concentrations of depleted Zymosan to stimulate Dectin-1.This method made it possible to show that the paracaspase MALT1 selectively regulates C-type lectin-like receptor signaling. It is essential to use well-characterized reference compounds. Pay attention to the procedure for the dilution of stock solutions.This is critical for compound with limited solubility.

Research

JoVE Journal

Biology

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