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On February 23, 2018, PubMed Central Canada (PMC Canada) will be taken offline permanently. No author manuscripts will be deleted, and the approximately 2,900 manuscripts authored by Canadian Institutes of Health Research (CIHR)-funded researchers currently in the archive will be copied to the National Research Council’s (NRC) Digital Repository over the coming months. These manuscripts along with all other content will also remain publicly searchable on PubMed Central (US) and Europe PubMed Central, meaning such manuscripts will continue to be compliant with the Tri-Agency Open Access Policy on Publications.

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1.  Defective positioning in granulomas but not lung-homing limits CD4 T cell interactions with Mycobacterium tuberculosis infected macrophages in rhesus macaques 
Mucosal immunology  2017;10.1038/mi.2017.60.
Protection against Mycobacterium tuberculosis (Mtb) infection requires CD4 T cells to migrate into the lung and interact with infected macrophages. In mice, less-differentiated CXCR3+ CD4 T cells migrate into the lung and suppress growth of Mtb, while CX3CR1+ terminally-differentiated Th1 cells accumulate in the blood vasculature and do not control pulmonary infection. Here we examine CD4 T cell differentiation and lung homing during primary Mtb infection of rhesus macaques. Mtb-specific CD4 T cells simultaneously appeared in the airways and blood ~21–28 days post-exposure, indicating that recently primed effectors are quickly recruited into the lungs after entering circulation. Mtb-specific CD4 T cells in granulomas display a tissue-parenchymal CXCR3+CX3CR1−PD-1hiCTLA-4+ phenotype. However, most granuloma CD4 T cells are found within the outer lymphocyte cuff, and few localize to the myeloid cell core containing the bacilli. Using the intravascular stain approach, we find essentially all Mtb-specific CD4 T cells in granulomas have extravasated across the vascular endothelium into the parenchyma. Therefore, it is unlikely that lung-homing defects introduced by terminal differentiation limit the migration of CD4 T cells into granulomas following primary Mtb infection of macaques. However, intralesional positioning defects within the granuloma may pose a major barrier to T cell-mediated immunity during tuberculosis.
PMCID: PMC5785573  PMID: 28745326
2.  BACH2 immunodeficiency illustrates an association between super-enhancers and haploinsufficiency 
Nature immunology  2017;18(7):813-823.
Transcriptional programs guiding lymphocyte differentiation depend on precise expression and timing of transcription factors (TFs). BACH2 is a TF essential for T- and B-lymphocytes and is associated with an archetypal super-enhancer (SE). Single nucleotide variants in the BACH2 locus associate with multiple autoimmune diseases but BACH2 mutations causing Mendelian monogenic primary immunodeficiency have not previously been identified. We describe a syndrome of BACH2-related immunodeficiency and autoimmunity (BRIDA) resulting from BACH2 haploinsufficiency. Patients had lymphocyte maturation defects, causing immunoglobulin deficiency and intestinal inflammation. The mutations disrupted protein stability by interfering with homodimerization or by causing aggregation. Analogous lymphocyte defects existed in Bach2 heterozygous mice. More generally, we found that genes causing monogenic haploinsufficient diseases are substantially enriched for TFs and SE-architecture. These observations show a new feature of SE-architecture in Mendelian diseases of immunity, that heterozygous mutations in SE-regulated genes identified on whole exome/genome sequencing may have greater significance than recognized.
PMCID: PMC5593426  PMID: 28530713
3.  Defining the target and the effect of imatinib on the filarial c-Abl homologue 
PLoS Neglected Tropical Diseases  2017;11(7):e0005690.
Previously we demonstrated the micro- and macrofilaricidal properties of imatinib in vitro. Here we use electron and multiphoton microscopy to define the target of imatinib in the adult and microfilarial stages of Brugia malayi and assess the effects of pharmacologically relevant levels of imatinib on the adult parasites.
After fixation of adult B. malayi males and females, sections were stained with polyclonal rabbit anti-c-Abl antibody (or isotype control) and imaged with multiphoton fluorescent microscopy. Microfilariae were fixed and labeled with rabbit anti-c-Abl IgG primary antibody followed by anti-rabbit gold conjugated secondary antibody and imaged using transmission electron microscopy (TEM; immunoEM). In addition, adult B. malayi males and females were exposed to 0 or 10μM of imatinib for 7 days following which they were prepared for transmission electron microscopy (TEM) to assess the drug’s effect on filarial ultrastructure.
Fluorescent localization of anti-c-Abl antibody demonstrated widespread uptake in the adult filariae, but the most intense signal was seen in the reproductive organs, muscle, and intestine of both male and female worms. Fluorescence was significantly more intense in the early microfilarial stage (i.e. early morula) compared with later development stages (i.e. pretzel). Anti-c-Abl antibody in the microfilariae localized to the nuclei. Based on TEM assessment following imatinib exposure, imatinib appeared to be detrimental to embryogenesis in the adult female B. malayi.
At pharmacologically achievable concentrations of imatinib, embryogenesis is impaired and possibly halted in adult filariae. Imatinib is likely a slow microfilaricide due to interference in intra-nuclear processes, which are slowly detrimental to the parasite and not immediately lethal, and thus may be used to lower the levels of L. loa microfilariae before they are treated within the context of conventional mass drug administration.
Author summary
While Loa loa, or the “African eye worm”, does not commonly cause clinical disease, infection with high blood levels of microfilariae from this helminth infection is problematic in those who receive mass drug administration (MDA) in the eradication efforts of lymphatic filariasis and onchocerciasis. Ivermectin, the drug of choice for both MDA programs, causes a rapid killing of Loa loa microfilariae and in those with high pre-treatment levels, a severe inflammatory reaction can result in encephalopathy, and rarely death. Using the filariae Brugia malayi as an in vitro surrogate model for any of the blood-borne filarial parasites (including Loa loa) we have previously shown that imatinib can act as a slow microfilaricide. Understanding imatinib’s targets in adult and microfilariae may predict the in vivo effects on Loa loa microfilarial loads, and anticipate potential side-effects for future clinical trials. In this study, we localized c-Abl, the target of imatinib, to the reproductive structures of adult B. malayi, and to the nuclei of the microfilariae. Pharmacologically achievable levels of imatinib most strikingly caused necrosis of developing microfilariae in adult female B. malayi. These data further support pursuing clinical trials in the safety and efficacy of imatinib for Loa. loa and other filarial co-infections.
PMCID: PMC5538754  PMID: 28727765
4.  Systemic toxoplasma infection triggers a long-term defect in the generation and function of naive T lymphocytes 
The Journal of Experimental Medicine  2016;213(13):3041-3056.
Kugler et al. show that systemic infection with Toxoplasma gondii triggers a long-term impairment in thymic function, which leads to an immunodeficient state reflected in decreased antimicrobial resistance.
Because antigen-stimulated naive T cells either die as effectors or enter the activated/memory pool, continuous egress of new T lymphocytes from thymus is essential for maintenance of peripheral immune homeostasis. Unexpectedly, we found that systemic infection with the protozoan Toxoplasma gondii triggers not only a transient increase in activated CD4+ Th1 cells but also a persistent decrease in the size of the naive CD4+ T lymphocyte pool. This immune defect is associated with decreased thymic output and parasite-induced destruction of the thymic epithelium, as well as disruption of the overall architecture of that primary lymphoid organ. Importantly, the resulting quantitative and qualitative deficiency in naive CD4+ T cells leads to an immunocompromised state that both promotes chronic toxoplasma infection and leads to decreased resistance to challenge with an unrelated pathogen. These findings reveal that systemic infectious agents, such as T. gondii, can induce long-term immune alterations associated with impaired thymic function. When accumulated during the lifetime of the host, such events, even when occurring at low magnitude, could be a contributing factor in immunological senescence.
PMCID: PMC5154934  PMID: 27849554
5.  31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016): part one 
Lundqvist, Andreas | van Hoef, Vincent | Zhang, Xiaonan | Wennerberg, Erik | Lorent, Julie | Witt, Kristina | Sanz, Laia Masvidal | Liang, Shuo | Murray, Shannon | Larsson, Ola | Kiessling, Rolf | Mao, Yumeng | Sidhom, John-William | Bessell, Catherine A. | Havel, Jonathan | Schneck, Jonathan | Chan, Timothy A. | Sachsenmeier, Eliot | Woods, David | Berglund, Anders | Ramakrishnan, Rupal | Sodre, Andressa | Weber, Jeffrey | Zappasodi, Roberta | Li, Yanyun | Qi, Jingjing | Wong, Philip | Sirard, Cynthia | Postow, Michael | Newman, Walter | Koon, Henry | Velcheti, Vamsidhar | Callahan, Margaret K. | Wolchok, Jedd D. | Merghoub, Taha | Lum, Lawrence G. | Choi, Minsig | Thakur, Archana | Deol, Abhinav | Dyson, Gregory | Shields, Anthony | Haymaker, Cara | Uemura, Marc | Murthy, Ravi | James, Marihella | Wang, Daqing | Brevard, Julie | Monaghan, Catherine | Swann, Suzanne | Geib, James | Cornfeld, Mark | Chunduru, Srinivas | Agrawal, Sudhir | Yee, Cassian | Wargo, Jennifer | Patel, Sapna P. | Amaria, Rodabe | Tawbi, Hussein | Glitza, Isabella | Woodman, Scott | Hwu, Wen-Jen | Davies, Michael A. | Hwu, Patrick | Overwijk, Willem W. | Bernatchez, Chantale | Diab, Adi | Massarelli, Erminia | Segal, Neil H. | Ribrag, Vincent | Melero, Ignacio | Gangadhar, Tara C. | Urba, Walter | Schadendorf, Dirk | Ferris, Robert L. | Houot, Roch | Morschhauser, Franck | Logan, Theodore | Luke, Jason J. | Sharfman, William | Barlesi, Fabrice | Ott, Patrick A. | Mansi, Laura | Kummar, Shivaani | Salles, Gilles | Carpio, Cecilia | Meier, Roland | Krishnan, Suba | McDonald, Dan | Maurer, Matthew | Gu, Xuemin | Neely, Jaclyn | Suryawanshi, Satyendra | Levy, Ronald | Khushalani, Nikhil | Wu, Jennifer | Zhang, Jinyu | Basher, Fahmin | Rubinstein, Mark | Bucsek, Mark | Qiao, Guanxi | MacDonald, Cameron | Hylander, Bonnie | Repasky, Elizabeth | Chatterjee, Shilpak | Daenthanasanmak, Anusara | Chakraborty, Paramita | Toth, Kyle | Meek, Megan | Garrett-Mayer, Elizabeth | Nishimura, Michael | Paulos, Chrystal | Beeson, Craig | Yu, Xuezhong | Mehrotra, Shikhar | Zhao, Fei | Evans, Kathy | Xiao, Christine | Holtzhausen, Alisha | Hanks, Brent A. | Scharping, Nicole | Menk, Ashley V. | Moreci, Rebecca | Whetstone, Ryan | Dadey, Rebekah | Watkins, Simon | Ferris, Robert | Delgoffe, Greg M. | Peled, Jonathan | Devlin, Sean | Staffas, Anna | Lumish, Melissa | Rodriguez, Kori Porosnicu | Ahr, Katya | Perales, Miguel | Giralt, Sergio | Taur, Ying | Pamer, Eric | van den Brink, Marcel R. M. | Jenq, Robert | Annels, Nicola | Pandha, Hardev | Simpson, Guy | Mostafid, Hugh | Harrington, Kevin | Melcher, Alan | Grose, Mark | Davies, Bronwyn | Au, Gough | Karpathy, Roberta | Shafren, Darren | Ricca, Jacob | Merghoub, Taha | Wolchok, Jedd D. | Zamarin, Dmitriy | Batista, Luciana | Marliot, Florence | Vasaturo, Angela | Carpentier, Sabrina | Poggionovo, Cécile | Frayssinet, Véronique | Fieschi, Jacques | Van den Eynde, Marc | Pagès, Franck | Galon, Jérôme | Hermitte, Fabienne | Smith, Sean G. | Nguyen, Khue | Ravindranathan, Sruthi | Koppolu, Bhanu | Zaharoff, David | Schvartsman, Gustavo | Bassett, Roland | McQuade, Jennifer L. | Haydu, Lauren E. | Davies, Michael A. | Tawbi, Hussein | Glitza, Isabella | Kline, Douglas | Chen, Xiufen | Fosco, Dominick | Kline, Justin | Overacre, Abigail | Chikina, Maria | Brunazzi, Erin | Shayan, Gulidanna | Horne, William | Kolls, Jay | Ferris, Robert L. | Delgoffe, Greg M. | Bruno, Tullia C. | Workman, Creg | Vignali, Dario | Adusumilli, Prasad S. | Ansa-Addo, Ephraim A | Li, Zihai | Gerry, Andrew | Sanderson, Joseph P. | Howe, Karen | Docta, Roslin | Gao, Qian | Bagg, Eleanor A. L. | Tribble, Nicholas | Maroto, Miguel | Betts, Gareth | Bath, Natalie | Melchiori, Luca | Lowther, Daniel E. | Ramachandran, Indu | Kari, Gabor | Basu, Samik | Binder-Scholl, Gwendolyn | Chagin, Karen | Pandite, Lini | Holdich, Tom | Amado, Rafael | Zhang, Hua | Glod, John | Bernstein, Donna | Jakobsen, Bent | Mackall, Crystal | Wong, Ryan | Silk, Jonathan D. | Adams, Katherine | Hamilton, Garth | Bennett, Alan D. | Brett, Sara | Jing, Junping | Quattrini, Adriano | Saini, Manoj | Wiedermann, Guy | Gerry, Andrew | Jakobsen, Bent | Binder-Scholl, Gwendolyn | Brewer, Joanna | Duong, MyLinh | Lu, An | Chang, Peter | Mahendravada, Aruna | Shinners, Nicholas | Slawin, Kevin | Spencer, David M. | Foster, Aaron E. | Bayle, J. Henri | Bergamaschi, Cristina | Ng, Sinnie Sin Man | Nagy, Bethany | Jensen, Shawn | Hu, Xintao | Alicea, Candido | Fox, Bernard | Felber, Barbara | Pavlakis, George | Chacon, Jessica | Yamamoto, Tori | Garrabrant, Thomas | Cortina, Luis | Powell, Daniel J. | Donia, Marco | Kjeldsen, Julie Westerlin | Andersen, Rikke | Westergaard, Marie Christine Wulff | Bianchi, Valentina | Legut, Mateusz | Attaf, Meriem | Dolton, Garry | Szomolay, Barbara | Ott, Sascha | Lyngaa, Rikke | Hadrup, Sine Reker | Sewell, Andrew Kelvin | Svane, Inge Marie | Fan, Aaron | Kumai, Takumi | Celis, Esteban | Frank, Ian | Stramer, Amanda | Blaskovich, Michelle A. | Wardell, Seth | Fardis, Maria | Bender, James | Lotze, Michael T. | Goff, Stephanie L. | Zacharakis, Nikolaos | Assadipour, Yasmine | Prickett, Todd D. | Gartner, Jared J. | Somerville, Robert | Black, Mary | Xu, Hui | Chinnasamy, Harshini | Kriley, Isaac | Lu, Lily | Wunderlich, John | Robbins, Paul F. | Rosenberg, Steven | Feldman, Steven A. | Trebska-McGowan, Kasia | Kriley, Isaac | Malekzadeh, Parisa | Payabyab, Eden | Sherry, Richard | Rosenberg, Steven | Goff, Stephanie L. | Gokuldass, Aishwarya | Blaskovich, Michelle A. | Kopits, Charlene | Rabinovich, Brian | Lotze, Michael T. | Green, Daniel S. | Kamenyeva, Olena | Zoon, Kathryn C. | Annunziata, Christina M. | Hammill, Joanne | Helsen, Christopher | Aarts, Craig | Bramson, Jonathan | Harada, Yui | Yonemitsu, Yoshikazu | Helsen, Christopher | Hammill, Joanne | Mwawasi, Kenneth | Denisova, Galina | Bramson, Jonathan | Giri, Rajanish | Jin, Benjamin | Campbell, Tracy | Draper, Lindsey M. | Stevanovic, Sanja | Yu, Zhiya | Weissbrich, Bianca | Restifo, Nicholas P. | Trimble, Cornelia L. | Rosenberg, Steven | Hinrichs, Christian S. | Tsang, Kwong | Fantini, Massimo | Hodge, James W. | Fujii, Rika | Fernando, Ingrid | Jochems, Caroline | Heery, Christopher | Gulley, James | Soon-Shiong, Patrick | Schlom, Jeffrey | Jing, Weiqing | Gershan, Jill | Blitzer, Grace | Weber, James | McOlash, Laura | Johnson, Bryon D. | Kiany, Simin | Gangxiong, Huang | Kleinerman, Eugenie S. | Klichinsky, Michael | Ruella, Marco | Shestova, Olga | Kenderian, Saad | Kim, Miriam | Scholler, John | June, Carl H. | Gill, Saar | Moogk, Duane | Zhong, Shi | Yu, Zhiya | Liadi, Ivan | Rittase, William | Fang, Victoria | Dougherty, Janna | Perez-Garcia, Arianne | Osman, Iman | Zhu, Cheng | Varadarajan, Navin | Restifo, Nicholas P. | Frey, Alan | Krogsgaard, Michelle | Landi, Daniel | Fousek, Kristen | Mukherjee, Malini | Shree, Ankita | Joseph, Sujith | Bielamowicz, Kevin | Byrd, Tiara | Ahmed, Nabil | Hegde, Meenakshi | Lee, Sylvia | Byrd, David | Thompson, John | Bhatia, Shailender | Tykodi, Scott | Delismon, Judy | Chu, Liz | Abdul-Alim, Siddiq | Ohanian, Arpy | DeVito, Anna Marie | Riddell, Stanley | Margolin, Kim | Magalhaes, Isabelle | Mattsson, Jonas | Uhlin, Michael | Nemoto, Satoshi | Villarroel, Patricio Pérez | Nakagawa, Ryosuke | Mule, James J. | Mailloux, Adam W. | Mata, Melinda | Nguyen, Phuong | Gerken, Claudia | DeRenzo, Christopher | Spencer, David M. | Gottschalk, Stephen | Mathieu, Mélissa | Pelletier, Sandy | Stagg, John | Turcotte, Simon | Minutolo, Nicholas | Sharma, Prannda | Tsourkas, Andrew | Powell, Daniel J. | Mockel-Tenbrinck, Nadine | Mauer, Daniela | Drechsel, Katharina | Barth, Carola | Freese, Katharina | Kolrep, Ulrike | Schult, Silke | Assenmacher, Mario | Kaiser, Andrew | Mullinax, John | Hall, MacLean | Le, Julie | Kodumudi, Krithika | Royster, Erica | Richards, Allison | Gonzalez, Ricardo | Sarnaik, Amod | Pilon-Thomas, Shari | Nielsen, Morten | Krarup-Hansen, Anders | Hovgaard, Dorrit | Petersen, Michael Mørk | Loya, Anand Chainsukh | Junker, Niels | Svane, Inge Marie | Rivas, Charlotte | Parihar, Robin | Gottschalk, Stephen | Rooney, Cliona M. | Qin, Haiying | Nguyen, Sang | Su, Paul | Burk, Chad | Duncan, Brynn | Kim, Bong-Hyun | Kohler, M. Eric | Fry, Terry | Rao, Arjun A. | Teyssier, Noam | Pfeil, Jacob | Sgourakis, Nikolaos | Salama, Sofie | Haussler, David | Richman, Sarah A. | Nunez-Cruz, Selene | Gershenson, Zack | Mourelatos, Zissimos | Barrett, David | Grupp, Stephan | Milone, Michael | Rodriguez-Garcia, Alba | Robinson, Matthew K. | Adams, Gregory P. | Powell, Daniel J. | Santos, João | Havunen, Riikka | Siurala, Mikko | Cervera-Carrascón, Víctor | Parviainen, Suvi | Antilla, Marjukka | Hemminki, Akseli | Sethuraman, Jyothi | Santiago, Laurelis | Chen, Jie Qing | Dai, Zhimin | Wardell, Seth | Bender, James | Lotze, Michael T. | Sha, Huizi | Su, Shu | Ding, Naiqing | Liu, Baorui | Stevanovic, Sanja | Pasetto, Anna | Helman, Sarah R. | Gartner, Jared J. | Prickett, Todd D. | Robbins, Paul F. | Rosenberg, Steven A. | Hinrichs, Christian S. | Bhatia, Shailender | Burgess, Melissa | Zhang, Hui | Lee, Tien | Klingemann, Hans | Soon-Shiong, Patrick | Nghiem, Paul | Kirkwood, John M. | Rossi, John M. | Sherman, Marika | Xue, Allen | Shen, Yueh-wei | Navale, Lynn | Rosenberg, Steven A. | Kochenderfer, James N. | Bot, Adrian | Veerapathran, Anandaraman | Gokuldass, Aishwarya | Stramer, Amanda | Sethuraman, Jyothi | Blaskovich, Michelle A. | Wiener, Doris | Frank, Ian | Santiago, Laurelis | Rabinovich, Brian | Fardis, Maria | Bender, James | Lotze, Michael T. | Waller, Edmund K. | Li, Jian-Ming | Petersen, Christopher | Blazar, Bruce R. | Li, Jingxia | Giver, Cynthia R. | Wang, Ziming | Grossenbacher, Steven K. | Sturgill, Ian | Canter, Robert J. | Murphy, William J. | Zhang, Congcong | Burger, Michael C. | Jennewein, Lukas | Waldmann, Anja | Mittelbronn, Michel | Tonn, Torsten | Steinbach, Joachim P. | Wels, Winfried S. | Williams, Jason B. | Zha, Yuanyuan | Gajewski, Thomas F. | Williams, LaTerrica C. | Krenciute, Giedre | Kalra, Mamta | Louis, Chrystal | Gottschalk, Stephen | Xin, Gang | Schauder, David | Jiang, Aimin | Joshi, Nikhil | Cui, Weiguo | Zeng, Xue | Menk, Ashley V. | Scharping, Nicole | Delgoffe, Greg M. | Zhao, Zeguo | Hamieh, Mohamad | Eyquem, Justin | Gunset, Gertrude | Bander, Neil | Sadelain, Michel | Askmyr, David | Abolhalaj, Milad | Lundberg, Kristina | Greiff, Lennart | Lindstedt, Malin | Angell, Helen K. | Kim, Kyoung-Mee | Kim, Seung-Tae | Kim, Sung | Sharpe, Alan D. | Ogden, Julia | Davenport, Anna | Hodgson, Darren R. | Barrett, Carl | Lee, Jeeyun | Kilgour, Elaine | Hanson, Jodi | Caspell, Richard | Karulin, Alexey | Lehmann, Paul | Ansari, Tameem | Schiller, Annemarie | Sundararaman, Srividya | Lehmann, Paul | Hanson, Jodi | Roen, Diana | Karulin, Alexey | Lehmann, Paul | Ayers, Mark | Levitan, Diane | Arreaza, Gladys | Liu, Fang | Mogg, Robin | Bang, Yung-Jue | O’Neil, Bert | Cristescu, Razvan | Friedlander, Philip | Wassman, Karl | Kyi, Chrisann | Oh, William | Bhardwaj, Nina | Bornschlegl, Svetlana | Gustafson, Michael P. | Gastineau, Dennis A. | Parney, Ian F. | Dietz, Allan B. | Carvajal-Hausdorf, Daniel | Mani, Nikita | Velcheti, Vamsidhar | Schalper, Kurt | Rimm, David | Chang, Serena | Levy, Ronald | Kurland, John | Krishnan, Suba | Ahlers, Christoph Matthias | Jure-Kunkel, Maria | Cohen, Lewis | Maecker, Holden | Kohrt, Holbrook | Chen, Shuming | Crabill, George | Pritchard, Theresa | McMiller, Tracee | Pardoll, Drew | Pan, Fan | Topalian, Suzanne | Danaher, Patrick | Warren, Sarah | Dennis, Lucas | White, Andrew M. | D’Amico, Leonard | Geller, Melissa | Disis, Mary L. | Beechem, Joseph | Odunsi, Kunle | Fling, Steven | Derakhshandeh, Roshanak | Webb, Tonya J. | Dubois, Sigrid | Conlon, Kevin | Bryant, Bonita | Hsu, Jennifer | Beltran, Nancy | Müller, Jürgen | Waldmann, Thomas | Duhen, Rebekka | Duhen, Thomas | Thompson, Lucas | Montler, Ryan | Weinberg, Andrew | Kates, Max | Early, Brandon | Yusko, Erik | Schreiber, Taylor H. | Bivalacqua, Trinity J. | Ayers, Mark | Lunceford, Jared | Nebozhyn, Michael | Murphy, Erin | Loboda, Andrey | Kaufman, David R. | Albright, Andrew | Cheng, Jonathan | Kang, S. Peter | Shankaran, Veena | Piha-Paul, Sarina A. | Yearley, Jennifer | Seiwert, Tanguy | Ribas, Antoni | McClanahan, Terrill K. | Cristescu, Razvan | Mogg, Robin | Ayers, Mark | Albright, Andrew | Murphy, Erin | Yearley, Jennifer | Sher, Xinwei | Liu, Xiao Qiao | Nebozhyn, Michael | Lunceford, Jared | Joe, Andrew | Cheng, Jonathan | Plimack, Elizabeth | Ott, Patrick A. | McClanahan, Terrill K. | Loboda, Andrey | Kaufman, David R. | Forrest-Hay, Alex | Guyre, Cheryl A. | Narumiya, Kohei | Delcommenne, Marc | Hirsch, Heather A. | Deshpande, Amit | Reeves, Jason | Shu, Jenny | Zi, Tong | Michaelson, Jennifer | Law, Debbie | Trehu, Elizabeth | Sathyanaryanan, Sriram | Hodkinson, Brendan P. | Hutnick, Natalie A. | Schaffer, Michael E. | Gormley, Michael | Hulett, Tyler | Jensen, Shawn | Ballesteros-Merino, Carmen | Dubay, Christopher | Afentoulis, Michael | Reddy, Ashok | David, Larry | Fox, Bernard | Jayant, Kumar | Agrawal, Swati | Agrawal, Rajendra | Jeyakumar, Ghayathri | Kim, Seongho | Kim, Heejin | Silski, Cynthia | Suisham, Stacey | Heath, Elisabeth | Vaishampayan, Ulka | Vandeven, Natalie | Viller, Natasja Nielsen | O’Connor, Alison | Chen, Hui | Bossen, Bolette | Sievers, Eric | Uger, Robert | Nghiem, Paul | Johnson, Lisa | Kao, Hsiang-Fong | Hsiao, Chin-Fu | Lai, Shu-Chuan | Wang, Chun-Wei | Ko, Jenq-Yuh | Lou, Pei-Jen | Lee, Tsai-Jan | Liu, Tsang-Wu | Hong, Ruey-Long | Kearney, Staci J. | Black, Joshua C. | Landis, Benjamin J. | Koegler, Sally | Hirsch, Brooke | Gianani, Roberto | Kim, Jeffrey | He, Ming-Xiao | Zhang, Bingqing | Su, Nan | Luo, Yuling | Ma, Xiao-Jun | Park, Emily | Kim, Dae Won | Copploa, Domenico | Kothari, Nishi | doo Chang, Young | Kim, Richard | Kim, Namyong | Lye, Melvin | Wan, Ee | Kim, Namyong | Lye, Melvin | Wan, Ee | Kim, Namyong | Lye, Melvin | Wan, Ee | Knaus, Hanna A. | Berglund, Sofia | Hackl, Hubert | Karp, Judith E. | Gojo, Ivana | Luznik, Leo | Hong, Henoch S. | Koch, Sven D. | Scheel, Birgit | Gnad-Vogt, Ulrike | Kallen, Karl-Josef | Wiegand, Volker | Backert, Linus | Kohlbacher, Oliver | Hoerr, Ingmar | Fotin-Mleczek, Mariola | Billingsley, James M. | Koguchi, Yoshinobu | Conrad, Valerie | Miller, William | Gonzalez, Iliana | Poplonski, Tomasz | Meeuwsen, Tanisha | Howells-Ferreira, Ana | Rattray, Rogan | Campbell, Mary | Bifulco, Carlo | Dubay, Christopher | Bahjat, Keith | Curti, Brendan | Urba, Walter | Vetsika, E-K | Kallergi, G. | Aggouraki, Despoina | Lyristi, Z. | Katsarlinos, P. | Koinis, Filippos | Georgoulias, V. | Kotsakis, Athanasios | Martin, Nathan T. | Aeffner, Famke | Kearney, Staci J. | Black, Joshua C. | Cerkovnik, Logan | Pratte, Luke | Kim, Rebecca | Hirsch, Brooke | Krueger, Joseph | Gianani, Roberto | Martínez-Usatorre, Amaia | Jandus, Camilla | Donda, Alena | Carretero-Iglesia, Laura | Speiser, Daniel E. | Zehn, Dietmar | Rufer, Nathalie | Romero, Pedro | Panda, Anshuman | Mehnert, Janice | Hirshfield, Kim M. | Riedlinger, Greg | Damare, Sherri | Saunders, Tracie | Sokol, Levi | Stein, Mark | Poplin, Elizabeth | Rodriguez-Rodriguez, Lorna | Silk, Ann | Chan, Nancy | Frankel, Melissa | Kane, Michael | Malhotra, Jyoti | Aisner, Joseph | Kaufman, Howard L. | Ali, Siraj | Ross, Jeffrey | White, Eileen | Bhanot, Gyan | Ganesan, Shridar | Monette, Anne | Bergeron, Derek | Amor, Amira Ben | Meunier, Liliane | Caron, Christine | Morou, Antigoni | Kaufmann, Daniel | Liberman, Moishe | Jurisica, Igor | Mes-Masson, Anne-Marie | Hamzaoui, Kamel | Lapointe, Rejean | Mongan, Ann | Ku, Yuan-Chieh | Tom, Warren | Sun, Yongming | Pankov, Alex | Looney, Tim | Au-Young, Janice | Hyland, Fiona | Conroy, Jeff | Morrison, Carl | Glenn, Sean | Burgher, Blake | Ji, He | Gardner, Mark | Mongan, Ann | Omilian, Angela R. | Conroy, Jeff | Bshara, Wiam | Angela, Omilian | Burgher, Blake | Ji, He | Glenn, Sean | Morrison, Carl | Mongan, Ann | Obeid, Joseph M. | Erdag, Gulsun | Smolkin, Mark E. | Deacon, Donna H. | Patterson, James W. | Chen, Lieping | Bullock, Timothy N. | Slingluff, Craig L. | Obeid, Joseph M. | Erdag, Gulsun | Deacon, Donna H. | Slingluff, Craig L. | Bullock, Timothy N. | Loffredo, John T. | Vuyyuru, Raja | Beyer, Sophie | Spires, Vanessa M. | Fox, Maxine | Ehrmann, Jon M. | Taylor, Katrina A. | Korman, Alan J. | Graziano, Robert F. | Page, David | Sanchez, Katherine | Ballesteros-Merino, Carmen | Martel, Maritza | Bifulco, Carlo | Urba, Walter | Fox, Bernard | Patel, Sapna P. | De Macedo, Mariana Petaccia | Qin, Yong | Reuben, Alex | Spencer, Christine | Guindani, Michele | Bassett, Roland | Wargo, Jennifer | Racolta, Adriana | Kelly, Brian | Jones, Tobin | Polaske, Nathan | Theiss, Noah | Robida, Mark | Meridew, Jeffrey | Habensus, Iva | Zhang, Liping | Pestic-Dragovich, Lidija | Tang, Lei | Sullivan, Ryan J. | Logan, Theodore | Khushalani, Nikhil | Margolin, Kim | Koon, Henry | Olencki, Thomas | Hutson, Thomas | Curti, Brendan | Roder, Joanna | Blackmon, Shauna | Roder, Heinrich | Stewart, John | Amin, Asim | Ernstoff, Marc S. | Clark, Joseph I. | Atkins, Michael B. | Kaufman, Howard L. | Sosman, Jeffrey | Weber, Jeffrey | McDermott, David F. | Weber, Jeffrey | Kluger, Harriet | Halaban, Ruth | Snzol, Mario | Roder, Heinrich | Roder, Joanna | Asmellash, Senait | Steingrimsson, Arni | Blackmon, Shauna | Sullivan, Ryan J. | Wang, Chichung | Roman, Kristin | Clement, Amanda | Downing, Sean | Hoyt, Clifford | Harder, Nathalie | Schmidt, Guenter | Schoenmeyer, Ralf | Brieu, Nicolas | Yigitsoy, Mehmet | Madonna, Gabriele | Botti, Gerardo | Grimaldi, Antonio | Ascierto, Paolo A. | Huss, Ralf | Athelogou, Maria | Hessel, Harald | Harder, Nathalie | Buchner, Alexander | Schmidt, Guenter | Stief, Christian | Huss, Ralf | Binnig, Gerd | Kirchner, Thomas | Sellappan, Shankar | Thyparambil, Sheeno | Schwartz, Sarit | Cecchi, Fabiola | Nguyen, Andrew | Vaske, Charles | Hembrough, Todd
Journal for Immunotherapy of Cancer  2016;4(Suppl 1):1-106.
PMCID: PMC5123387
6.  Sam68 Is Required for DNA Damage Responses via Regulating Poly(ADP-ribosyl)ation 
PLoS Biology  2016;14(9):e1002543.
The rapid and robust synthesis of polymers of adenosine diphosphate (ADP)-ribose (PAR) chains, primarily catalyzed by poly(ADP-ribose) polymerase 1 (PARP1), is crucial for cellular responses to DNA damage. However, the precise mechanisms through which PARP1 is activated and PAR is robustly synthesized are not fully understood. Here, we identified Src-associated substrate during mitosis of 68 kDa (Sam68) as a novel signaling molecule in DNA damage responses (DDRs). In the absence of Sam68, DNA damage-triggered PAR production and PAR-dependent DNA repair signaling were dramatically diminished. With serial cellular and biochemical assays, we demonstrated that Sam68 is recruited to and significantly overlaps with PARP1 at DNA lesions and that the interaction between Sam68 and PARP1 is crucial for DNA damage-initiated and PARP1-conferred PAR production. Utilizing cell lines and knockout mice, we illustrated that Sam68-deleted cells and animals are hypersensitive to genotoxicity caused by DNA-damaging agents. Together, our findings suggest that Sam68 plays a crucial role in DDR via regulating DNA damage-initiated PAR production.
The RNA-binding protein Sam68 has unexpected function in the early signaling of DNA damage, and is critical for the activation and regulation of poly(ADP-ribose) polymerase 1 in response to DNA damage.
Author Summary
Maintaining genome integrity is crucial for all organisms, and failure to do so can lead to fatal diseases such as cancer. Exposure to challenging environments can induce DNA strand breaks or other lesions; thus, rapid and appropriate DNA damage responses (DDRs) need to be in place to detect and repair the damage. Cellular networks use a variety of signaling molecules and post-translational modifications that are crucial for the signaling of DNA breaks to repair machineries. Poly(adenosine diphosphate [ADP]-ribosyl)ation (PARylation) and activation of the enzyme poly(ADP-ribose) polymerase 1 (PARP1) is a post-translational modification that occurs within seconds upon DNA damage detection and triggers downstream DDR signaling; however, it remains obscure whether other molecules, beyond DNA strand breaks, stimulate or control PARP1 activity. We report here that a novel DDR signaling molecule, Src-associated substrate during mitosis of 68 kDa (Sam68), has a crucial function in governing the DNA damage-initiated PARP1 activation and polymers of ADP-ribose (PAR) production. We show that Sam68 is recruited to and significantly overlaps with PARP1 at DNA lesions and that the Sam68-PARP1 interaction is critical for DNA damage-initiated PARP1 activation and PAR production both in vitro and in vivo. Sam68-deleted cells and animals have a diminished PAR-dependent DNA repair signaling and are hypersensitive to genotoxicity caused by DNA-damaging agents. Hence, our data reveal an unexpected function for Sam68 in DNA damage-initiated early signaling and provide a novel mechanism on the activation and regulation of PARP1 in DDR.
PMCID: PMC5026359  PMID: 27635653
7.  B-lymphocyte Specific loss of Ric-8A Results in a Gα Protein Deficit and Severe Humoral Immunodeficiency 
Resistance to inhibitors of cholinesterase 8A (Ric-8A) is a highly evolutionarily conserved cytosolic protein initially identified in C. elegans, where it was assigned a regulatory role in asymmetric cell divisions. It functions as a guanine nucleotide exchange factor for Gαi, Gαq, and Gα12/13 and as a molecular chaperone required for the initial association of nascent Gα subunits with cellular membranes in embryonic stem cell lines. To test its role in hematopoiesis and B lymphocytes specifically, we generated ric8fl/flvav1-cre and ric8fl/flmb1-cre mice. The major hematopoietic cell lineages developed in the ric8fl/flvav1-cre mice, notwithstanding severe reduction in Gαi2/3, Gαq, and Gα13 proteins. B lymphocyte specific loss of Ric-8A did not compromise bone marrow B lymphopoiesis, but splenic marginal zone B cell development failed, and B cells underpopulated lymphoid organs. The ric8fl/flmb1-cre B cells exhibited poor responses to chemokines, abnormal trafficking, improper in situ positioning, and loss of polarity components during B cell differentiation. The ric8fl/flmb1-cre mice had a severely disrupted lymphoid architecture and poor primary and secondary antibody responses. In B lymphocytes, Ric-8A is essential for normal Gα protein levels; and is required for B cell differentiation, trafficking, and antibody responses.
PMCID: PMC4546893  PMID: 26232433
Ric-8A; heterotrimeric G-protein; marginal zone; hypogammaglobulemia; asymmetric cell division
8.  Locally Produced IL-10 Limits Cutaneous Vaccinia Virus Spread 
PLoS Pathogens  2016;12(3):e1005493.
Skin infection with the poxvirus vaccinia (VV) elicits a powerful, inflammatory cellular response that clears virus infection in a coordinated, spatially organized manner. Given the high concentration of pro-inflammatory effectors at areas of viral infection, it is unclear how tissue pathology is limited while virus-infected cells are being eliminated. To better understand the spatial dynamics of the anti-inflammatory response to a cutaneous viral infection, we first screened cytokine mRNA expression levels after epicutaneous (ec.) VV infection and found a large increase the anti-inflammatory cytokine IL-10. Ex vivo analyses revealed that T cells in the skin were the primary IL-10-producing cells. To understand the distribution of IL-10-producing T cells in vivo, we performed multiphoton intravital microscopy (MPM) of VV-infected mice, assessing the location and dynamic behavior of IL-10 producing cells. Although virus-specific T cells were distributed throughout areas of the inflamed skin lacking overt virus-infection, IL-10+ cells closely associated with large keratinocytic foci of virus replication where they exhibited similar motility patterns to bulk antigen-specific CD8+ T cells. Paradoxically, neutralizing secreted IL-10 in vivo with an anti-IL-10 antibody increased viral lesion size and viral replication. Additional analyses demonstrated that IL-10 antibody administration decreased recruitment of CCR2+ inflammatory monocytes, which were important for reducing viral burden in the infected skin. Based upon these findings, we conclude that spatially concentrated IL-10 production limits cutaneous viral replication and dissemination, likely through modulation of the innate immune repertoire at the site of viral growth.
Author Summary
While ineffective antiviral immune responses can result in illness or even death, excessive host responses can also cause substantial injury. Anti-inflammatory proteins play an important regulatory role in limiting immune-mediated damage, but it is unknown where the cells making these modulators need to be for the greatest effect. The best-described immune-response-limiting protein is the cytokine interleukin-10 (IL-10), which is produced during infections with disparate pathogens including viruses, bacteria, and parasites. Despite the preponderance of IL-10 production during infection, we do not know the tissue distribution of this cytokine or whether it acts in localized areas. To address these questions, we studied the behavior of IL-10-producing cells after infecting mice with vaccinia virus (VV), the attenuated vaccine virus used to eradicate smallpox. Using microscopy to image infection in the skin of living mice, we found that IL-10 is produced by cells that surround areas of virus replication, rather than throughout the tissue as we anticipated. Even more surprisingly, we found that IL-10 promotes (rather than impedes) virus clearance, likely by shaping the tissue response of innate immune cells. These data show that supplying anti-inflammatory cytokines at precise areas of infected tissue can dramatically limit viral replication and damage.
PMCID: PMC4798720  PMID: 26991092
9.  Canonical and Noncanonical G-Protein Signaling Helps Coordinate Actin Dynamics To Promote Macrophage Phagocytosis of Zymosan 
Molecular and Cellular Biology  2014;34(22):4186-4199.
Both chemotaxis and phagocytosis depend upon actin-driven cell protrusions and cell membrane remodeling. While chemoattractant receptors rely upon canonical G-protein signaling to activate downstream effectors, whether such signaling pathways affect phagocytosis is contentious. Here, we report that Gαi nucleotide exchange and signaling helps macrophages coordinate the recognition, capture, and engulfment of zymosan bioparticles. We show that zymosan exposure recruits F-actin, Gαi proteins, and Elmo1 to phagocytic cups and early phagosomes. Zymosan triggered an increase in intracellular Ca2+ that was partially sensitive to Gαi nucleotide exchange inhibition and expression of GTP-bound Gαi recruited Elmo1 to the plasma membrane. Reducing GDP-Gαi nucleotide exchange, decreasing Gαi expression, pharmacologically interrupting Gβγ signaling, or reducing Elmo1 expression all impaired phagocytosis, while favoring the duration that Gαi remained GTP bound promoted it. Our studies demonstrate that targeting heterotrimeric G-protein signaling offers opportunities to enhance or retard macrophage engulfment of phagocytic targets such as zymosan.
PMCID: PMC4248717  PMID: 25225330
10.  Neutrophil Recruitment to Lymph Nodes Limits Local Humoral Response to Staphylococcus aureus 
PLoS Pathogens  2015;11(4):e1004827.
Neutrophils form the first line of host defense against bacterial pathogens. They are rapidly mobilized to sites of infection where they help marshal host defenses and remove bacteria by phagocytosis. While splenic neutrophils promote marginal zone B cell antibody production in response to administered T cell independent antigens, whether neutrophils shape humoral immunity in other lymphoid organs is controversial. Here we investigate the neutrophil influx following the local injection of Staphylococcus aureus adjacent to the inguinal lymph node and determine neutrophil impact on the lymph node humoral response. Using intravital microscopy we show that local immunization or infection recruits neutrophils from the blood to lymph nodes in waves. The second wave occurs temporally with neutrophils mobilized from the bone marrow. Within lymph nodes neutrophils infiltrate the medulla and interfollicular areas, but avoid crossing follicle borders. In vivo neutrophils form transient and long-lived interactions with B cells and plasma cells, and their depletion augments production of antigen-specific IgG and IgM in the lymph node. In vitro activated neutrophils establish synapse- and nanotube-like interactions with B cells and reduce B cell IgM production in a TGF- β1 dependent manner. Our data reveal that neutrophils mobilized from the bone marrow in response to a local bacterial challenge dampen the early humoral response in the lymph node.
Author Summary
Highly antibiotic resistant Staphylococcus aureus (S. aureus) are an important human pathogen and major cause of hospital acquired infections. An early host defense mechanism against bacterial infection is neutrophil recruitment, which helps eliminate the bacteria at the site of invasion. However, unless quickly neutralized, pathogens such as S. aureus can gain access to nearby lymph nodes via draining lymphatics. Lymph nodes protect the host by mobilizing additional resources that limit further pathogen dissemination. These include recruitment of neutrophils to the lymph node to directly target pathogens and the initiation of adaptive immune mechanisms, such as the humoral immune response, which transforms B lymphocytes capable of making pathogen specific antibodies into antibody producing plasma cells. Using a mouse model that allows direct visualization of lymphocytes, neutrophils, and fluorescently-labeled S. aureus in lymph nodes, we document the rapid appearance of bacteria in the lymph node following local S. aureus infection. We characterize the dynamic influx of neutrophils that occurs as a consequence and reveal direct B cell-neutrophil interactions within the lymph node parenchyma. We find that while lymph node neutrophils rapidly engage bacteria, they limit the subsequent humoral immune response likely by producing Transforming Growth Factor-β1, a factor known to limit B cell responses. These finding have important implication for our understanding of B cell responses against potent pathogens such as S. aureus and for the design of effective vaccines.
PMCID: PMC4401519  PMID: 25884622
11.  Resistance to Inhibitors of Cholinesterase (Ric)-8A and Gαi Contribute to Cytokinesis Abscission by Controlling Vacuolar Protein-Sorting (Vps)34 Activity 
PLoS ONE  2014;9(1):e86680.
Resistance to inhibitors of cholinesterase (Ric)-8A is a guanine nucleotide exchange factor for Gαi, Gαq, and Gα12/13, which is implicated in cell signaling and as a molecular chaperone required for the initial association of nascent Gα subunits with cellular membranes. Ric-8A, Gαi subunits, and their regulators are localized at the midbody prior to abscission and linked to the final stages of cell division. Here, we identify a molecular mechanism by which Ric-8A affects cytokinesis and abscission by controlling Vps34 activity. We showed that Ric-8A protein expression is post-transcriptionally controlled during the cell cycle reaching its maximum levels at mitosis. A FRET biosensor created to measure conformational changes in Ric-8A by FLIM (Fluorescence Lifetime Imaging Microscopy) revealed that Ric-8A was in a close-state during mitosis and particularly so at cytokinesis. Lowering Ric-8A expression delayed the abscission time of dividing cells, which correlated with increased intercellular bridge length and multinucleation. During cytokinesis, Ric-8A co-localized with Vps34 at the midbody along with Gαi and LGN, where these proteins functioned to regulate Vps34 phosphatidylinositol 3-kinase activity.
PMCID: PMC3897744  PMID: 24466196
12.  The Loss of RGS Protein-Gαi2 Interactions Results in Markedly Impaired Mouse Neutrophil Trafficking to Inflammatory Sites 
Molecular and Cellular Biology  2012;32(22):4561-4571.
Neutrophils are first responders rapidly mobilized to inflammatory sites by a tightly regulated, nonredundant hierarchy of chemoattractants. These chemoattractants engage neutrophil cell surface receptors triggering heterotrimeric G-protein Gαi subunits to exchange GDP for GTP. By limiting the duration that Gαi subunits remain GTP bound, RGS proteins modulate chemoattractant receptor signaling. Here, we show that neutrophils with a genomic knock in of a mutation that disables regulator of G-protein signaling (RGS)-Gαi2 interactions accumulate in the bone marrow and mobilize poorly to inflammatory sites. These defects are attributable to enhanced sensitivity to background signals, prolonged chemoattractant receptor signaling, and inappropriate CXCR2 downregulation. Intravital imaging revealed a failure of the mutant neutrophils to accumulate at and stabilize sites of sterile inflammation. Furthermore, these mice could not control a nonlethal Staphylococcus aureus infection. Neutrophil RGS proteins establish a threshold for Gαi activation, helping to coordinate desensitization mechanisms. Their loss renders neutrophils functionally incompetent.
PMCID: PMC3486189  PMID: 22966200
13.  VE-PTP controls blood vessel development by balancing Tie-2 activity 
The Journal of Cell Biology  2009;185(4):657-671.
Vascular endothelial protein tyrosine phosphatase (VE-PTP) is an endothelial-specific receptor-type tyrosine phosphatase that associates with Tie-2 and VE-cadherin. VE-PTP gene disruption leads to embryonic lethality, vascular remodeling defects, and enlargement of vascular structures in extraembryonic tissues. We show here that antibodies against the extracellular part of VE-PTP mimic the effects of VE-PTP gene disruption exemplified by vessel enlargement in allantois explants. These effects require the presence of the angiopoietin receptor Tie-2. Analyzing the mechanism we found that anti–VE-PTP antibodies trigger endocytosis and selectively affect Tie-2–associated, but not VE-cadherin–associated VE-PTP. Dissociation of VE-PTP triggers the activation of Tie-2, leading to enhanced endothelial cell proliferation and enlargement of vascular structures through activation of Erk1/2. Importantly, the antibody effect on vessel enlargement is also observed in newborn mice. We conclude that VE-PTP is required to balance Tie-2 activity and endothelial cell proliferation, thereby controlling blood vessel development and vessel size.
PMCID: PMC2711575  PMID: 19451274
14.  VE-PTP maintains the endothelial barrier via plakoglobin and becomes dissociated from VE-cadherin by leukocytes and by VEGF 
The Journal of Experimental Medicine  2008;205(12):2929-2945.
We have shown recently that vascular endothelial protein tyrosine phosphatase (VE-PTP), an endothelial-specific membrane protein, associates with vascular endothelial (VE)–cadherin and enhances VE-cadherin function in transfected cells (Nawroth, R., G. Poell, A. Ranft, U. Samulowitz, G. Fachinger, M. Golding, D.T. Shima, U. Deutsch, and D. Vestweber. 2002. EMBO J. 21:4885–4895). We show that VE-PTP is indeed required for endothelial cell contact integrity, because down-regulation of its expression enhanced endothelial cell permeability, augmented leukocyte transmigration, and inhibited VE-cadherin–mediated adhesion. Binding of neutrophils as well as lymphocytes to endothelial cells triggered rapid (5 min) dissociation of VE-PTP from VE-cadherin. This dissociation was only seen with tumor necrosis factor α–activated, but not resting, endothelial cells. Besides leukocytes, vascular endothelial growth factor also rapidly dissociated VE-PTP from VE-cadherin, indicative of a more general role of VE-PTP in the regulation of endothelial cell contacts. Dissociation of VE-PTP and VE-cadherin in endothelial cells was accompanied by tyrosine phoshorylation of VE-cadherin, β-catenin, and plakoglobin. Surprisingly, only plakoglobin but not β-catenin was necessary for VE-PTP to support VE-cadherin adhesion in endothelial cells. In addition, inhibiting the expression of VE-PTP preferentially increased tyrosine phosphorylation of plakoglobin but not β-catenin. In conclusion, leukocytes interacting with endothelial cells rapidly dissociate VE-PTP from VE-cadherin, weakening endothelial cell contacts via a mechanism that requires plakoglobin but not β-catenin.
PMCID: PMC2585844  PMID: 19015309

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