Este trabalho foi apoiado financeiramente pelo NIH (1 R01 AI095338-01A1).

Os autores declaram que não têm interesses financeiros concorrentes.

A migração de neutrófilos através das superfícies epiteliais mucosas é uma característica comum na patologia da doença após a infecção com patógenos bacterianos3. A metodologia descrita aqui oferece uma abordagem rápida e direta para isolar experimentalmente este evento discreto usando um sistema de ensaio de cocultura in vitro derivado de células humanas que modela uma característica do processo inflamatório desencadeado por infecções bacterianas. Este sistema foi originalmente dese...

As superfícies mucosas servem como barreiras físicas e imunológicas que proporcionam proteção contra ameaças externas generalizadas no meio ambiente1,2. Esta barreira epitelial protetora pode ser comprometida quando organismos patogênicos invadem2. No caso de um patógeno bacteriano, esse encontro muitas vezes instiga um processo inflamatório ativando o sistema imunológico inato e desencadeando uma rápida mobilização de granulócitos de primeiros socorros conhecidos como neutrófilos2-4. Agentes chemotactic facilitando o recrutamento de neutrófilos são produzidos em parte pelas células epiteliais mucosas que buscam livrar o hospedeiro do patógenoofensivo 2-4. Infiltração de neutrófilo excessivo ou não resolvida da superfície epitelial mucosa pode causar patologia significativa1,5. Isso é consequência de danos teciduais não específicos causados pelo arsenal antibacteriano de neutrófilo5-7. Nesses casos, a capacidade de liberação bacteriana de neutrófilos é ofuscada pela destruição do tecido hospedeiro durante um insulto infeccioso.  A interrupção da função de barreira epitelial protetora pode levar a uma maior exposição do tecido subjacente a microrganismos e/ou toxinas, exacerbando ainda mais a patologia da doença8,9. Essas consequências podem ser observadas em múltiplos sistemas de órgãos, incluindo o pulmão e o trato digestivo1,5. Além disso, condições inflamatórias não infecciosas, como crises graves de asma, doença pulmonar obstrutiva crônica (DPOC), síndrome do desconforto respiratório agudo (ARDS) e doença inflamatória intestinal (DII) são marcadas pela ruptura patológica da barreira epitelial mucosa por uma resposta neutrófila excessiva4,5,10-12.
O complexo processo de recrutamento de neutrófilos após infecção mucosa envolve várias etapas compartimentadas1,5,13,14. Primeiro, os neutrófilos devem sair de circulação através de uma série de interações célula-celular que facilitam a migração trans-endotelial1,13. Os neutrófilos navegam em seguida no espaço intersticial existente contendo matriz extracelular1,14. Para alcançar o lúmen da mucosa infectada, os neutrófilos devem migrar através da barreira epitelial1,4,5. Este intrincado fenômeno multistep é frequentemente investigado em agregado usando modelos in vivo animais de infecção15. Tais modelos são úteis para estabelecer a necessidade de fatores específicos, como quimiocinas, moléculas de adesão ou caminhos de sinalização que participam do processo global, mas são em grande parte inadequados para a resolução de contribuições moleculares críticas para cada etapa compartimentalizada distinta16. Sistemas in vitro coculturados modelando migração trans-endotelial, trans matricial ou trans-epitelial de neutrófilos têm sido particularmente úteis a este respeito1,14,16,17.
Um robusto sistema de ensaio de cocultura foi desenvolvido com o objetivo de decifrar mecanismos responsáveis pela migração trans-epitelial de neutrófilos em resposta à infecção patogênica18-22. Este modelo envolve infectar a superfície apical de camadas de células epiteliais humanas polarizadas com um patógeno bacteriano seguido pela aplicação de neutrófilos humanos recém-isolados na superfície basolateral18-22. Os neutrófilos migram através da barreira epitelial em resposta a produtos quimiolíticos derivados da epitelial secretados após infecção patogênica18,21-23. Este sistema modelo tem sido empregado usando culturas epiteliais intestinais e pulmonares expostas a patógenos bacterianos específicos do tecido apropriado e revelou novos mecanismos moleculares provavelmente importantes para o processo de recrutamento de neutrófilos durante a infecção mucosa3,8,19,24-28. A força deste modelo de cocultura in vitro é que uma abordagem reducionista permite ao pesquisador manipular experimentalmente o patógeno, a barreira epitelial e/ou o neutrófilo em um sistema bem controlado, altamente reprodutível e bastante barato. Os insights obtidos a partir dessa abordagem podem ser efetivamente aproveitados para realizar análises focadas de eventos compartimentados durante o recrutamento de neutrófilos usando modelos de infecção in vivo 22,29,30.
Este artigo demonstra os múltiplos passos necessários para o estabelecimento bem-sucedido deste modelo reprodutível para explorar a migração trans-epitelial induzida pelo patógeno. As barreiras epiteliais pulmonares infectadas com o patógeno Pseudomonas aeruginosa são destaque neste artigo; no entanto, outras epitélios teciduais e patógenos podem ser substituídos por pequenas modificações. A semeadura e a colheita de camadas de células epiteliais pulmonares polarizadas em filtros transwell permeáveis revestidos de colágeno invertidos são detalhados aqui, assim como o crescimento da P. aeruginosa patogênica e o isolamento de neutrófilos de sangue inteiro. Como esses componentes são combinados para observar a migração trans-epitelial induzida pelo patógeno é apresentada juntamente com controles positivos e negativos apropriados para estabelecer um ensaio reprodutível. A versatilidade dessa abordagem para examinar vários aspectos da migração trans-epitelial induzida pelo patógeno é discutida com referência a estudos específicos na literatura.

<table border="0" cellpadding="0" cellspacing="0" width="1470">
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">NCl-H292 cells</td>
			<td style="width:147px;">ATCC</td>
			<td style="width:137px;">CRL-1848</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">RPMI-1640 medium</td>
			<td style="width:147px;">ATCC</td>
			<td style="width:137px;">30-2001</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Pseudomonas aeruginosa PAO1</td>
			<td style="width:147px;">ATCC</td>
			<td style="width:137px;">#47085</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Escherichia coli MC1000</td>
			<td style="width:147px;">ATCC</td>
			<td style="width:137px;">#39531</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">D-PBS (1x) liquid</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">14190-144</td>
			<td style="width:667px;">without calcium and magnesium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Heat Inactivated Fetal bovine serum</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">10082-147</td>
			<td style="width:667px;">10% added to culture medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Penicillin-Streptomycin</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">15140-122</td>
			<td style="width:667px;">100x: 10,000 units of penicillin and 10,000 &#181;g of streptomycin per ml.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Trypsin-EDTA (0.05%)</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">25300-062</td>
			<td style="width:667px;">50 ml aliquots are stored frozen at -20 &#186;C.&#160; Aliquot in use can be stored at 4 &#186;C short-term.&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Hank&#39;s Balanced Salt Solution - HBSS(-)</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">14175-079</td>
			<td style="width:667px;">Sterile, without calcium and magnesium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Trypan Blue Solution</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">15250-061.</td>
			<td style="width:667px;">Stock = 0.4%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Collagen, Rat Tail</td>
			<td style="width:147px;">Invitrogen</td>
			<td style="width:137px;">A10483-01</td>
			<td style="width:667px;">Can also be isolated in the laboratory directly from the tails of rats using standard protocols</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Citric acid</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">C1909-500G</td>
			<td style="width:667px;">Component of 1 M citrate buffer and acid citrate dextrose (ACD) solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Sodium Citrate</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">S4641-500G</td>
			<td style="width:667px;">Component of 1 M citrate buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Dextrose anhydrous</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">D8066-250G</td>
			<td style="width:667px;">Component of acid citrate dextrose (ACD) solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Ammonium Chloride</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">213330-500G</td>
			<td style="width:667px;">Component of red blood cell (RBC) lysis buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Sodium bicarbonate</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">S6014-500G</td>
			<td style="width:667px;">Component of red blood cell (RBC) lysis buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">EDTA</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">ED-100G</td>
			<td style="width:667px;">Component of red blood cell (RBC) lysis buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">HBSS(+) powder</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">H1387-10L</td>
			<td style="width:667px;">Key component of HBSS+</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">HEPES</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">H3375-500G</td>
			<td style="width:667px;">Component of HBSS+</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Sigmacote</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">SL2-25ML</td>
			<td style="width:667px;">Follow vendor instructions to coat glass pipette tips</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Triton X-100</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">T-9284</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">2,2&#39;-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">A9941-50TAB</td>
			<td style="width:667px;">Key component of ABTS substrate solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">30% Hydrogen Peroxide Solution</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">H1009-100ML</td>
			<td style="width:667px;">Component of ABTS substrate solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">N-Formyl-Met-Leu-Phe (fMLP or fMLF)</td>
			<td style="width:147px;">Sigma-Aldrich&#160;</td>
			<td style="width:137px;">F-3506</td>
			<td style="width:667px;">A Stock solution of 10 mM in DMSO should be prepared and aliquots stored at -20 &#186;C.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Gelatin Type B</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">M-12026</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Pseudomonas isolation agar&#160;</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">DF0927-17-1</td>
			<td style="width:667px;">Follow manufacturer&#8217;s instructions to make PIA plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Ficoll-Paque PLUS&#160;</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">45-001-749</td>
			<td style="width:667px;">Optional, can improve neutrophil purity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;"></td>
			<td style="width:147px;"></td>
			<td style="width:137px;"></td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;"></td>
			<td style="width:147px;"></td>
			<td style="width:137px;"></td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;"></td>
			<td style="width:147px;"></td>
			<td style="width:137px;"></td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;"></td>
			<td style="width:147px;"></td>
			<td style="width:137px;"></td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;"></td>
			<td style="width:147px;"></td>
			<td style="width:137px;"></td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Name of Material / Equipment</td>
			<td style="width:147px;">Company</td>
			<td style="width:137px;">Catalog Number</td>
			<td style="width:667px;">Comments</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">24-well migration plate</td>
			<td style="width:147px;">Corning Incorporated</td>
			<td style="width:137px;">#3524</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">24-well wash plate</td>
			<td style="width:147px;">Falcon</td>
			<td style="width:137px;">35-1147</td>
			<td style="width:667px;">Can be reused if soaked in 70% ethanol and washed thoroughly prior to reuse</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">96-well plate</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">#12565501</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:520px;">Transwell Permeable Supports&#160;</td>
			<td style="width:147px;">Corning Incorporated</td>
			<td style="width:137px;">#3415</td>
			<td style="width:667px;">Polycarbonate; Diameter: 6.5 mm; Growth area: 0.33 cm2; Dish style: 24-well plate; Pore size: 3.0 &#181;m</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Petri dish</td>
			<td style="width:147px;">Falcon</td>
			<td style="width:137px;">35-1013</td>
			<td style="width:667px;">Each Petri dish holds 24 inverted 0.33 cm2 Transwells.&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">500 ml 0.2 &#956;m filter / flask</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">09-740-25A</td>
			<td style="width:667px;">To sterilize acid citrate dextrose (ACD) solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">5-3/4 in glass Pasteur pipette</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">13-678-20A</td>
			<td style="width:667px;">Coat tips with Sigmacote prior to use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Hemostat</td>
			<td style="width:147px;">Fisher Scientific</td>
			<td style="width:137px;">13-812-14</td>
			<td style="width:667px;">Curved, Serrated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Invertoskop Inverted Microscope</td>
			<td style="width:147px;">Zeiss</td>
			<td style="width:137px;">#342222</td>
			<td style="width:667px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:520px;">Versa-Max Microplate Reader</td>
			<td style="width:147px;">Molecular Devices</td>
			<td style="width:137px;">#432789</td>
			<td style="width:667px;"></td>
		</tr>
	</tbody>
</table>

in vitro coculture assay to assess pathogen induced neutrophil trans-epithelial migration

As superfícies mucosas servem como barreiras protetoras contra organismos patogênicos. As respostas imunes inatas são ativadas ao detectar patógenos que levam à infiltração de tecidos com células inflamatórias migratórias, principalmente neutrófilos. Esse processo tem o potencial de ser destrutivo para os tecidos se excessivo ou mantido em um estado não resolvido.  Modelos in vitro coculturizados podem ser utilizados para estudar os mecanismos moleculares únicos envolvidos na migração trans-epitelial induzida pelo patógeno. Este tipo de modelo fornece versatilidade no design experimental com oportunidade de manipulação controlada do patógeno, barreira epitelial ou neutrófilo. A infecção patogênica da superfície apical de monocamadas epiteliais polarizadas cultivadas em filtros transwell permeáveis instiga a migração basolateral fisiologicamente relevante para a migração trans-epitelial apical de neutrófilos aplicados à superfície basolateral. O modelo in vitro descrito aqui demonstra os múltiplos passos necessários para demonstrar a migração de neutrófilos através de uma monocamada epitelial pulmonar polarizada que foi infectada com P. aeruginosa patogênica (PAO1). A semeadura e a colheita de transwells permeáveis com células epiteliais pulmonares derivadas humanas é descrita, juntamente com o isolamento de neutrófilos de sangue humano inteiro e cultivo de PAO1 e não-patogênico K12 E. coli (MC1000).  O processo de emigração e a análise quantitativa de neutrófilos migrados com sucesso que foram mobilizados em resposta à infecção patogênica são mostrados com dados representativos, incluindo controles positivos e negativos. Este sistema de modelo in vitro pode ser manipulado e aplicado a outras superfícies mucosas. Respostas inflamatórias que envolvem infiltração excessiva de neutrófilos podem ser destrutivas para os tecidos hospedeiros e podem ocorrer na ausência de infecções patogênicas. Uma melhor compreensão dos mecanismos moleculares que promovem a migração trans-epitelial de neutrófilos através da manipulação experimental do sistema de ensaio de cocultura in vitro descrito aqui tem um potencial significativo para identificar novos alvos terapêuticos para uma gama de doenças infecciosas mucosas, bem como inflamatórias.

Vários estudos demonstraram que as camadas epiteliais infectadas por patógenos facilitam a migração trans-epitelial de neutrófilos3,8,19,24-28,31,32. Isso ocorre por meio de uma indução específica de patógeno de um gradiente químico quimiofilo quimiofilo derivado de células epiteliais3,23. Por exemplo, p. aeruginosa patogênica interagindo com a superfície apical das células epiteliais pulmonares faz com que um número substancial de neutrófilos migrem através da camada epite...

Watch this Scientific Journal Video about In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration at JoVE.com

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

A migração trans-epitelial de neutrófilos em resposta à infecção bacteriana mucosa contribui para lesão epitelial e doença clínica. Foi desenvolvido um modelo in vitro que combina patógenos, neutrófilos humanos e camadas de células epiteliais humanas polarizadas cultivadas em filtros transwell para facilitar investigações para desvendar os mecanismos moleculares que orquestram esse fenômeno.

In vitro Ensaio de cocultura para avaliar migração trans epitelial de neutrófilo induzida por patógenos

Mucosal surfaces serve as protective barriers against pathogenic organisms.&#160;Innate immune responses are activated upon sensing pathogen leading to ...

in-vitro-coculture-assay-to-assess-pathogen-induced-neutrophil-trans

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Immunology and Infection

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

17.4K visualizações.  Harvard Medical School. A migração trans-epitelial de neutrófilos em resposta à infecção bacteriana mucosa contribui para lesão epitelial e doença clínica. Foi desenvolvido um modelo in vitro que combina patógenos, neutrófilos humanos e camadas de células epiteliais humanas polarizadas cultivadas em filtros transwell para facilitar investigações para desvendar os mecanismos moleculares que orquestram esse fenômeno.

Vídeo: In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

Assay for Pathogen-Associated Molecular Pattern (PAMP)-Triggered Immunity (PTI) in Plants

To perceive potential pathogens in their environment, plants use pattern recognition receptors (PRRs) present on their plasma membranes. PRRs recognize conserved microbial features called pathogen-associated molecular patterns (PAMPs) and this detection leads to PAMP-triggered immunity (PTI), which effectively prevents colonization of plant tissues by non-pathogens1,2. The most well studied system in PTI is the FLS2-dependent pathway3. FLS2 recognizes the PAMP flg22 that is a component of bacterial flagellin. 
Successful pathogens possess virulence factors or effectors that can suppress PTI and allow the pathogen to cause disease1. Some plants in turn possess resistance genes that detect effectors or their activity, which leads to effector-triggered immunity (ETI)2.
We describe a cell death-based assay for PTI modified from Oh and Collmer4. The assay was standardized in N. benthamiana, which is being used increasingly as a model system for the study of plant-pathogen interactions5. PTI is induced by infiltration of a non-pathogenic bacterial strain into leaves. Seven hours later, a bacterial strain that either causes disease or which activates ETI is infiltrated into an area overlapping the original infiltration zone. PTI induced by the first infiltration is able to delay or prevent the appearance of cell death due to the second challenge infiltration. Conversely, the appearance of cell death in the overlapping area of inoculation indicates a breakdown of PTI. 
Four different combinations of inducers of PTI and challenge inoculations were standardized (Table 1). The assay was tested on non-silenced N. benthamiana plants that served as the control and plants silenced for FLS2 that were predicted to be compromised in their ability to develop PTI.

Assay for Pathogen-Associated Molecular Pattern PAMP-Triggered Immunity PTI in Plants

A cell death-based assay for PTI in Nicotiana benthamiana plants is described.

Ensaio para Pathogen-Associated Padrão Molecular (PAMP) Triggered-Imunidade (PTI) em Plantas

To perceive potential pathogens in their environment, plants use pattern recognition receptors (PRRs) present on their plasma membranes. PRRs recognize ...

Imunologia e Infecção

Tracking Neutrophil Intraluminal Crawling, Transendothelial Migration and Chemotaxis in Tissue by Intravital Video Microscopy

The recruitment of circulating leukocytes from blood stream to the inflamed tissue is a crucial and complex process of inflammation1,2. In the postcapillary venules of inflamed tissue, leukocytes initially tether and roll on the luminal surface of venular wall. Rolling leukocytes arrest on endothelium and undergo firm adhesion in response to chemokine or other chemoattractants on the venular surface. Many adherent leukocytes relocate from the initial site of adhesion to the junctional extravasation site in endothelium, a process termed intraluminal crawling3. Following crawling, leukocytes move across endothelium (transmigration) and migrate in extravascular tissue toward the source of chemoattractant (chemotaxis)4. Intravital microscopy is a powerful tool for visualizing leukocyte-endothelial cell interactions in vivo and revealing cellular and molecular mechanisms of leukocyte recruitment2,5. In this report, we provide a comprehensive description of using brightfield intravital microscopy to visualize and determine the detailed processes of neutrophil recruitment in mouse cremaster muscle in response to the gradient of a neutrophil chemoattractant. To induce neutrophil recruitment, a small piece of agarose gel (~1-mm3 size) containing neutrophil chemoattractant MIP-2 (CXCL2, a CXC chemokine) or WKYMVm (Trp-Lys-Tyr-Val-D-Met, a synthetic analog of bacterial peptide) is placed on the muscle tissue adjacent to the observed postcapillary venule. With time-lapsed video photography and computer software ImageJ, neutrophil intraluminal crawling on endothelium, neutrophil transendothelial migration and the migration and chemotaxis in tissue are visualized and tracked. This protocol allows reliable and quantitative analysis of many neutrophil recruitment parameters such as intraluminal crawling velocity, transmigration time, detachment time, migration velocity, chemotaxis velocity and chemotaxis index in tissue. We demonstrate that using this protocol, these neutrophil recruitment parameters can be stably determined and the single cell locomotion conveniently tracked in vivo.

We describe a protocol of brightfield intravital microscopy for measuring dynamic neutrophil-endothelial cell interactions during neutrophil recruitment in response to the source of a neutrophil chemoattractant in vivo. Neutrophil intraluminal crawling, transendothelial migration and chemotaxis in mouse cremaster muscle tissue are visualized with time-lapsed video photography and tracked with ImageJ.

Rastreamento Crawling neutrófilos Intraluminal, migração transendotelial e Quimiotaxia em tecido por Microscopia intravital Vídeo

The recruitment of circulating leukocytes from blood stream to the inflamed tissue is a crucial and complex process of inflammation1,2. In the ...

Quantitative In vitro Assay to Measure Neutrophil Adhesion to Activated Primary Human Microvascular Endothelial Cells under Static Conditions

The vascular endothelium plays an integral part in the inflammatory response. During the acute phase of inflammation, endothelial cells (ECs) are activated by host mediators or directly by conserved microbial components or host-derived danger molecules. Activated ECs express cytokines, chemokines and adhesion molecules that mobilize, activate and retain leukocytes at the site of infection or injury. Neutrophils are the first leukocytes to arrive, and adhere to the endothelium through a variety of adhesion molecules present on the surfaces of both cells. The main functions of neutrophils are to directly eliminate microbial threats, promote the recruitment of other leukocytes through the release of additional factors, and initiate wound repair. Therefore, their recruitment and attachment to the endothelium is a critical step in the initiation of the inflammatory response. In this report, we describe an in vitro neutrophil adhesion assay using calcein AM-labeled primary human neutrophils to quantitate the extent of microvascular endothelial cell activation under static conditions. This method has the additional advantage that the same samples quantitated by fluorescence spectrophotometry can also be visualized directly using fluorescence microscopy for a more qualitative assessment of neutrophil binding.

Quantitative In vitro Assay to Measure Neutrophil Adhesion to Activated Primary Human Microvascular Endothelial Cells under Static Conditions

Neutrophil adherence to the activated endothelium at sites of infection is an integral component of the host's inflammatory response. Described in this report is a neutrophil binding assay that allows for the in vitro quantitation of primary human neutrophil binding to endothelial cells activated by inflammatory mediators under static conditions.

Quantitativo<em&gt; In vitro</em&gt; Ensaio medir a adesão de neutrófilos ativados primárias células humanas endoteliais microvasculares em condições estáticas

The vascular  endothelium plays an integral part in the inflammatory response. During the  acute phase of inflammation, endothelial cells (ECs) are ...

Quantitative Assessment of Human Neutrophil Migration Across a Cultured Bladder Epithelium

The recruitment of immune cells from the periphery to the site of inflammation is an essential step in the innate immune response at any mucosal surface. During infection of the urinary bladder, polymorphonuclear leukocytes (PMN; neutrophils) migrate from the bloodstream and traverse the bladder epithelium. Failure to resolve infection in the absence of a neutrophilic response demonstrates the importance of PMN in bladder defense. To facilitate colonization of the bladder epithelium, uropathogenic Escherichia coli (UPEC), the causative agent of the majority of urinary tract infections (UTIs), dampen the acute inflammatory response using a variety of partially defined mechanisms. To further investigate the interplay between host and bacterial pathogen, we developed an in vitro model of this aspect of the innate immune response to UPEC. In the transuroepithelial neutrophil migration assay, a variation on the Boyden chamber, cultured bladder epithelial cells are grown to confluence on the underside of a permeable support. PMN are isolated from human venous blood and are applied to the basolateral side of the bladder epithelial cell layers. PMN migration representing the physiologically relevant basolateral-to-apical direction in response to bacterial infection or chemoattractant molecules is enumerated using a hemocytometer. This model can be used to investigate interactions between UPEC and eukaryotic cells as well as to interrogate the molecular requirements for the traversal of bladder epithelia by PMN. The transuroepithelial neutrophil migration model will further our understanding of the initial inflammatory response to UPEC in the bladder.

We developed an in vitro model that mimics an important component of the acute inflammatory response during infection of the bladder with uropathogenic Escherichia coli. The transuroepithelial neutrophil migration assay enables quantitative assessment of human neutrophil migration across bladder epithelia, cultured on permeable supports, in response to bacterial infection or chemoattractant substances.

Avaliação quantitativa de neutrófilos humanos migração através de um Cultivadas bexiga Epitélio

The recruitment of immune cells from the periphery to the site of inflammation is an essential step in the innate immune response at any mucosal surface. ...

Human Neutrophil Flow Chamber Adhesion Assay

Neutrophil firm adhesion to endothelial cells plays a critical role in inflammation in both health and disease. The process of neutrophil firm adhesion involves many different adhesion molecules including members of the &beta;2 integrin family and their counter-receptors of the ICAM family. Recently, naturally occurring genetic variants in both &beta;2 integrins and ICAMs are reported to be associated with autoimmune disease. Thus, the quantitative adhesive capacity of neutrophils from individuals with varying allelic forms of these adhesion molecules is important to study in relation to mechanisms underlying development of autoimmunity. Adhesion studies in flow chamber systems can create an environment with fluid shear stress similar to that observed in the blood vessel environment in vivo. Here, we present a method using a flow chamber assay system to study the quantitative adhesive properties of human peripheral blood neutrophils to human umbilical vein endothelial cell (HUVEC) and to purified ligand substrates. With this method, the neutrophil adhesive capacities from donors with different allelic variants in adhesion receptors can be assessed and compared. This method can also be modified to assess adhesion of other primary cell types or cell lines.

A method of quantitating neutrophil adhesion is reported. This method creates a dynamic flow environment similar to that encountered in a blood vessel. It allows the investigation of neutrophil adhesion to either purified adhesion molecules (ligand) or endothelial cell substrate (HUVEC) in a context similar to the in vivo environment with sheer stress.

Fluxo de Neutrófilos Humanos Secção Ensaio de Adesão

Neutrophil firm adhesion to endothelial cells plays a critical role in inflammation in both health and disease. The process of neutrophil firm adhesion ...

Neutrophil Isolation and Analysis to Determine their Role in Lymphoma Cell Sensitivity to Therapeutic Agents

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of inflammation. They are key players in the innate immune system and play major roles in cancer biology. Neutrophils have been proposed as key mediators of malignant transformation, tumor progression, angiogenesis and in the modulation of the antitumor immunity; through their release of soluble factors or their interaction with tumor cells. To characterize the specific functions of neutrophils, a fast and reliable method is coveted for in vitro isolation of neutrophils from human blood. Here, a density gradient separation method is demonstrated to isolate neutrophils as well as mononuclear cells from the blood. The procedure consists of layering the density gradient solution such as Ficoll carefully above the diluted blood obtained from patients diagnosed with chronic lymphocytic leukemia (CLL), followed by centrifugation, isolation of mononuclear layer, separation of neutrophils from RBCsby dextran then lysis of residual erythrocytes. This method has been shown to isolate neutrophils &#8805; 90 % pure. To mimic the tumor microenvironment, 3-dimensional (3D) experiments were performed using basement membrane matrix such as Matrigel. Given the short half-life of neutrophils in vitro, 3D experiments with fresh human neutrophils cannot be performed. For this reason promyelocytic HL60 cells are differentiated along the granulocytic pathway using the differentiation inducers dimethyl sulfoxide (DMSO) and retinoic acid (RA). The aim of our experiments is to study the role of neutrophils on the sensitivity of lymphoma cells to anti-lymphoma agents. However these methods can be generalized to study the interactions of neutrophils or neutrophil-like cells with a large range of cell types in different situations.

Neutrophils are the most abundant type of white blood cells. The isolation of neutrophils from human blood by density gradient separation method and the differentiation of human promyelocytic (HL60) cells along the granulocytic pathway are described here; to test their role on sensitivity of lymphoma cells to anti-lymphoma agents.

Isolamento de neutrófilos e análise para determinar seu papel na linfoma sensibilidade das células a agentes terapêuticos

Neutrophils are the most abundant (40% to 75%) type of white blood cells and among the first inflammatory cells to migrate towards the site of ...

A Novel In Vitro Wound Healing Assay to Evaluate Cell Migration

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to stimulate cell migration. Importantly, cell migration is a rate-limiting event during the wound-healing process to re-establish the integrity and normal function of tissue layers after injury. The advantage of this method over the classical assay, which is based on a manually made scratch in a cell monolayer, is the usage of special silicone culture inserts providing two compartments to create a cell-free pseudo-wound field with a well-defined width (500 &#956;m). In addition, due to an automated image analysis platform, it is possible to rapidly obtain quantitative data on the speed of wound closure and cell migration. More precisely, the effect of two frog-skin AMPs on the migration of bronchial epithelial cells will be shown. Furthermore, pretreatment of these cells with specific inhibitors will provide information on the molecular mechanisms underlying such events.

A Novel In Vitro Wound Healing Assay to Evaluate Cell Migration

Here, we present a protocol to evaluate the effect of peptides on the migration of bronchial epithelial cells. This method allows for the rapid and highly reproducible obtainment of quantitative data on the speed of cell migration and wound closure.

Um romance em Vitro ferida cura ensaio para avaliar a migração celular

The aim of this work is to show a novel method to evaluate the ability of some immunomodulatory molecules, such as antimicrobial peptides (AMPs), to ...

Analysis of Shear Flow-induced Migration of Murine Marginal Zone B Cells In Vitro

Marginal zone B cells (MZBs) are a population of B cells that reside in the mouse splenic marginal zones that envelop follicles. To reach the follicles, MZBs must migrate up the shear force of blood flow. We present here a method for analyzing this flow-induced MZB migration in vitro. First, MZBs are isolated from the mouse spleen. Second, MZBs are settled on integrin ligands in flow chamber slides, exposed to shear flow, and imaged under a microscope while migrating. Third, images of the migrating MZBs are processed using the MTrack2 automatic cell tracking plugin for ImageJ, and the resulting cell tracks are quantified using the Ibidi chemotaxis tool. The migration data reveal how fast the cells move, how often they change direction, whether the shear flow vector affects their migration direction, and which integrin ligands are involved. Although we use MZBs, the method can easily be adapted for analyzing migration of any leukocyte that responds to the force of shear flow.

Marginal zone B cells (MZBs) respond to the force of shear flow by re-orienting their migration path up the flow. This protocol shows how to record and analyze the migration using a fluidics unit, pump, microscope imaging system, and free software.

Análise de cisalhamento induzida pelo fluxo de migração de murino Marginal Zone B células In Vitro

Marginal zone B cells (MZBs) are a population of B cells that reside in the mouse splenic marginal zones that envelop follicles. To reach the follicles, ...

A High-throughput Assay to Assess and Quantify Neutrophil Extracellular Trap Formation

Neutrophil extracellular traps (NETs) are immunogenic extracellular DNA structures that can be released by neutrophils upon a wide variety of triggers. NETs have been demonstrated to serve as an important host defense mechanism that traps and kills microorganisms. On the other hand, they have been implicated in diverse systemic autoimmune diseases. NETs are immunogenic and toxic structures that contain a pool of relevant autoantigens including anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) and systemic lupus erythematosus (SLE). Different forms of NETs can be induced depending on the stimulus. The amount of NETs can be quantified using different techniques including measuring DNA release in supernatants, measuring DNA-complexed with NET-molecules like myeloperoxidase (MPO) or neutrophil elastase (NE), measuring the presence of citrullinated histones by fluorescence microscopy, or flow cytometric detection of NET-components which all have different features regarding their specificity, sensitivity, objectivity, and quantity. Here is a protocol to quantify ex vivo NET formation in a highly-sensitive, high-throughput manner by using three-dimensional immunofluorescence confocal microscopy. This protocol can be applied to address various research questions about NET formation and degradation in health and disease.

This protocol describes a highly sensitive and high throughput neutrophil extracellular trap (NET) assay for the semi-automated quantification of ex vivo NET formation by immunofluorescence three-dimensional confocal microscopy. This protocol can be used to evaluate NET formation and degradation after different stimuli and can be used to study potential NET-targeted therapies.

Um ensaio de alta produtividade para avaliar e quantificar a formação de neutrófilos extracelular armadilha

Neutrophil extracellular traps (NETs) are immunogenic extracellular DNA structures that can be released by neutrophils upon a wide variety of triggers. ...

Opsonophagocytic Killing Assay to Assess Immunological Responses Against Bacterial Pathogens

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental procedure in which phagocytic cells are co-cultured with bacterial units. The immune cells will phagocytose and kill the bacterial cultures in a complement-dependent manner. The efficiency of the immune-mediated cell killing is dependent on a number of factors and can be used to determine how different bacterial cultures compare with regard to resistance to cell death. In this way, the efficacy of potential immune-based therapeutics can be assessed against specific bacterial strains and/or serotypes. In this protocol, we describe a simplified OPKA that utilizes basic culture conditions and cell counting to determine bacterial cell viability after co-culture with treatment conditions and HL-60 immune cells. This method has been successfully utilized with a number of different pneumococcal serotypes, capsular and acapsular strains, and other bacterial species. The advantages of this OPKA protocol are its simplicity, versatility (as this assay is not limited to antibody treatments as opsonins), and minimization of time and reagents to assess basic experimental groups.

This opsonophagocytic killing assay is used to compare the ability of phagocytic immune cells to respond to and kill bacteria based on different treatments and/or conditions. Classically, this assay serves as the gold&#160;standard for assessing effector functions of antibodies raised against a bacterium as opsonin.

Ensaio de matar Opsonophagocytic para avaliar as respostas imunológicas contra patógenos bacterianos

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental ...