Publications by Year: 2011

2011
Villablanca EJ, Cassani B, von Andrian UH, Mora RJ. Blocking lymphocyte localization to the gastrointestinal mucosa as a therapeutic strategy for inflammatory bowel diseases. Gastroenterology. 2011;140 (6) :1776-84.Abstract
Lymphocyte migration (homing) to specific tissues has an important role during protective and pathological immune responses, including inflammatory bowel diseases. Lymphocytes use integrin α4β7 and the chemokine receptor CCR9 to localize to the gastrointestinal mucosa; their respective ligands, mucosal addressin cell adhesion molecule-1 and CCL25, are displayed on endothelial cells in intestinal postcapillary venules. Although gastrointestinal-homing receptors are required for lymphocyte migration to the intestine in the noninflamed steady state, their role during inflammation is a matter of debate. Reagents designed to block interactions between these receptors and their ligands have had variable degrees of success in animal models of inflammatory bowel diseases and patients. We discuss the mechanisms involved in lymphocyte localization to the intestinal mucosa and how they can be applied to therapy for inflammatory bowel diseases.
1-s2.0-s0016508511001685-main.pdf
Textor J, Peixoto A, Henrickson SE, Sinn M, von Andrian UH, Westermann J. Defining the quantitative limits of intravital two-photon lymphocyte tracking. Proc Natl Acad Sci U S A. 2011;108 (30) :12401-6.Abstract
Two-photon microscopy has substantially advanced our understanding of cellular dynamics in the immune system. Cell migration can now be imaged in real time in the living animal. Strikingly, the migration of naive lymphocytes in secondary lymphoid tissue appears predominantly random. It is unclear, however, whether directed migration may escape detection in this random background. Using a combination of mathematical modeling and experimental data, we investigate the extent to which modern two-photon imaging can rule out biologically relevant directed migration. For naive T cells migrating in uninfected lymph nodes (LNs) at average 3D speeds of around 18 μm/min, we rule out uniform directed migration of more than 1.7 μm/min at the 95% confidence level, confirming that T cell migration is indeed mostly random on a timescale of minutes. To investigate whether this finding still holds for longer timescales, we use a 3D simulation of the naive T cell LN transit. A pure random walk predicts a transit time of around 16 h, which is in good agreement with experimental results. A directional bias of only 0.5 μm/min-less than 3% of the cell speed-would already accelerate the transit twofold. These results jointly strengthen the random walk analogy for naive T cell migration in LNs, but they also emphasize that very small deviations from random migration can still be important. Our methods are applicable to cells of any type and can be used to reanalyze existing datasets.
pnas.1102288108.pdf
Lencer WI, von Andrian UH. Eliciting mucosal immunity. N Engl J Med. 2011;365 (12) :1151-3. nihms782373.pdf
Mazo IB, Massberg S, von Andrian UH. Hematopoietic stem and progenitor cell trafficking. Trends Immunol. 2011;32 (10) :493-503.Abstract
Migration of hematopoietic stem cells (HSCs) is essential during embryonic development and throughout adult life. During embryogenesis, trafficking of HSCs is responsible for the sequential colonization of different hematopoietic organs by blood-producing cells. In adulthood, circulation of HSCs maintains homeostasis of the hematopoietic system and participates in innate immune responses. HSC trafficking is also crucial in clinical settings such as bone marrow (BM) and stem cell transplantation. This review provides an overview of the molecular and cellular signals that control and fine-tune trafficking of HSCs and hematopoietic progenitor cells in embryogenesis and during postnatal life. We also discuss the potential clinical utility of therapeutic approaches to modulate HSC trafficking in patients.
1-s2.0-s1471490611001177-main.pdf
Sitia G, Iannacone M, Aiolfi R, Isogawa M, van Rooijen N, Scozzesi C, Bianchi ME, von Andrian UH, Chisari FV, Guidotti LG. Kupffer cells hasten resolution of liver immunopathology in mouse models of viral hepatitis. PLoS Pathog. 2011;7 (6) :e1002061.Abstract
Kupffer cells (KCs) are widely considered important contributors to liver injury during viral hepatitis due to their pro-inflammatory activity. Herein we utilized hepatitis B virus (HBV)-replication competent transgenic mice and wild-type mice infected with a hepatotropic adenovirus to demonstrate that KCs do not directly induce hepatocellular injury nor do they affect the pathogenic potential of virus-specific CD8 T cells. Instead, KCs limit the severity of liver immunopathology. Mechanistically, our results are most compatible with the hypothesis that KCs contain liver immunopathology by removing apoptotic hepatocytes in a manner largely dependent on scavenger receptors. Apoptotic hepatocytes not readily removed by KCs become secondarily necrotic and release high-mobility group box 1 (HMGB-1) protein, promoting organ infiltration by inflammatory cells, particularly neutrophils. Overall, these results indicate that KCs resolve rather than worsen liver immunopathology.
kupffer_cells_hasten_resolution_of_liver_immunopathology_in_mouse_models_of_viral_hepatitis.pdf video_s1_1.mov video_s3.mov video_s2_1.mov
Villablanca EJ, Wang S, de Calisto J, Gomes DCO, Kane MA, Napoli JL, Blaner WS, Kagechika H, Blomhoff R, Rosemblatt M, et al. MyD88 and retinoic acid signaling pathways interact to modulate gastrointestinal activities of dendritic cells. Gastroenterology. 2011;141 (1) :176-85.Abstract
BACKGROUND & AIMS: Gut-associated dendritic cells (DC) metabolize vitamin A into all-trans retinoic acid (RA), which is required to induce lymphocytes to localize to the gastrointestinal tract and promotes the differentiation of Foxp3+ regulatory T cells and IgA antibody-secreting cells. We investigated whether RA functions in a positive-feedback loop in DC to induce its own synthesis. METHODS: We measured levels of retinoids in intestinal tissues from mice and assessed the role of RA in the functional specialization of gut-associated DC in cell cultures and mice. We used pharmacologic antagonists to determine the signaling pathways involved in regulation of DC and used MyD88-/- mice to determine the contribution of Toll-like receptor signaling in RA-mediated effects on DC. RESULTS: The concentration of retinoids decreased in a proximal-to-distal gradient along the intestine, which correlated with the activity of gut-specific DC. Importantly, RA regulated the ability of gut-associated DC to produce RA, induce T cells to localize to the gastrointestinal tract, and generate regulatory T cells and IgA-secreting cells. RA was sufficient to induce its own production by extraintestinal DC in vitro and in vivo. RA-mediated regulation of DC required signaling through the mitogen-activated protein kinase signaling pathway and unexpectedly required MyD88, which is conventionally associated with Toll-like receptor, interleukin-1, and interleukin-18 signaling. CONCLUSIONS: RA is necessary and sufficient to induce DC to regulate T-cell localization to the gastrointestinal tract and IgA secretion. Our findings also indicate crosstalk between the RA receptor and MyD88-dependent Toll-like receptor signaling pathways.
suppm.pdf 1-s2.0-s0016508511005191-main.pdf
Paust S, von Andrian UH. Natural killer cell memory. Nat Immunol. 2011;12 (6) :500-8.Abstract
Natural killer (NK) cells are bone marrow–derived granular lymphocytes that have a key role in immune defense against viral and bacterial infections and malignancies. NK cells are traditionally defined as cells of the innate immune response because they lack RAG recombinase–dependent clonal antigen receptors. However, evidence suggests that specific subsets of mouse NK cells can nevertheless develop long-lived and highly specific memory to a variety of antigens. Here we review published evidence of NK cell–mediated, RAG-independent adaptive immunity. We also compare and contrast candidate mechanisms for mammalian NK cell memory and antigen recognition with other examples of RAG-independent pathways that generate antigen receptor diversity in non-mammalian species and discuss NK cell memory in the context of lymphocyte evolution.
ni.2032.pdf
Allen SJ, Hamrah P, Gate D, Mott KR, Mantopoulos D, Zheng L, Town T, Jones C, von Andrian UH, Freeman GJ, et al. The role of LAT in increased CD8+ T cell exhaustion in trigeminal ganglia of mice latently infected with herpes simplex virus 1. J Virol. 2011;85 (9) :4184-97.Abstract
Herpes simplex virus (HSV) infection is a classic example of latent viral infection in humans and experimental animal models. The HSV-1 latency-associated transcript (LAT) plays a major role in the HSV-1 latency reactivation cycle and thus in recurrent disease. Whether the presence of LAT leads to generation of dysfunctional T cell responses in the trigeminal ganglia (TG) of latently infected mice is not known. To address this issue, we used LAT-positive [LAT(+)] and LAT-deficient [LAT(-)] viruses to evaluate the effect of LAT on CD8 T cell exhaustion in TG of latently infected mice. The amount of latency as determined by quantitative reverse transcription-PCR (qRT-PCR) of viral DNA in total TG extracts was 3-fold higher with LAT(+) than with LAT(-) virus. LAT expression and increased latency correlated with increased mRNA levels of CD8, PD-1, and Tim-3. PD-1 is both a marker for exhaustion and a primary factor leading to exhaustion, and Tim-3 can also contribute to exhaustion. These results suggested that LAT(+) TG contain both more CD8(+) T cells and more CD8(+) T cells expressing the exhaustion markers PD-1 and Tim-3. This was confirmed by flow cytometry analyses of expression of CD3/CD8/PD-1/Tim-3, HSV-1, CD8(+) T cell pentamer (specific for a peptide derived from residues 498 to 505 of glycoprotein B [gB(498-505)]), interleukin-2 (IL-2), and tumor necrosis factor alpha (TNF-α). The functional significance of PD-1 and its ligands in HSV-1 latency was demonstrated by the significantly reduced amount of HSV-1 latency in PD-1- and PD-L1-deficient mice. Together, these results may suggest that both PD-1 and Tim-3 are mediators of CD8(+) T cell exhaustion and latency in HSV-1 infection.
jvi.02290-10.pdf
Chevrier N, Mertins P, Artyomov MN, Shalek AK, Iannacone M, Ciaccio MF, Gat-Viks I, Tonti E, DeGrace MM, Clauser KR, et al. Systematic discovery of TLR signaling components delineates viral-sensing circuits. Cell. 2011;147 (4) :853-67.Abstract
Deciphering the signaling networks that underlie normal and disease processes remains a major challenge. Here, we report the discovery of signaling components involved in the Toll-like receptor (TLR) response of immune dendritic cells (DCs), including a previously unkown pathway shared across mammalian antiviral responses. By combining transcriptional profiling, genetic and small-molecule perturbations, and phosphoproteomics, we uncover 35 signaling regulators, including 16 known regulators, involved in TLR signaling. In particular, we find that Polo-like kinases (Plk) 2 and 4 are essential components of antiviral pathways in vitro and in vivo and activate a signaling branch involving a dozen proteins, among which is Tnfaip2, a gene associated with autoimmune diseases but whose role was unknown. Our study illustrates the power of combining systematic measurements and perturbations to elucidate complex signaling circuits and discover potential therapeutic targets.
1-s2.0-s0092867411012700-main.pdf
Meyer-Luehmann M, Mora RJ, Mielke M, Spires-Jones TL, de Calignon A, von Andrian UH, Hyman BT. T cell mediated cerebral hemorrhages and microhemorrhages during passive Aβ immunization in APPPS1 transgenic mice. Mol Neurodegener. 2011;6 :22.Abstract
BACKGROUND: Immunization against amyloid-β (Aβ), the peptide that accumulates in the form of senile plaques and in the cerebrovasculature in Alzheimer's disease (AD), causes a dramatic immune response that prevents plaque formation and clears accumulated Aβ in transgenic mice. In a clinical trial of Aβ immunization, some patients developed meningoencephalitis and hemorrhages. Neuropathological investigations of patients who died after the trial showed clearance of amyloid pathology, but also a powerful immune response involving activated T cells probably underlying the negative effects of the immunization. RESULTS: To define the impact of T cells on this inflammatory response we used passive immunization and adoptive transfer to separate the effect of IgG and T cell mediated effects on microhemorrhage in APPPS1 transgenic mice. Neither anti Aβ IgG nor adoptively transferred T cells, alone, led to increased cerebrovascular damage. However, the combination of adoptively transferred T cells and passive immunization led to massive cerebrovascular bleeding that ranged from multiple microhemorrhages in the parenchyma to large hematomas. CONCLUSIONS: Our results indicate that vaccination can lead to Aβ and T cell induced cerebral micro-hemorrhages and acute hematomas, which are greatly exacerbated by T cell mediated activity.
1750-1326-6-22_1.pdf 13024_2010_178_moesm1_esm.doc