Publications

2023
Eshaghi B, Schudel A, Sadeghi I, Chen Z, Lee A, Kanelli  M, Tierney F, Han J, Ingalls B, Francis D, et al. The role of engineered materials in mucosal vaccination strategies. Nature Reviews Materials. 2023. Publisher's VersionAbstract
Mucosal pathogens, as exemplified by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human immunodeficiency virus (HIV) and Mycobacterium tuberculosis, lead to substantial morbidity and mortality worldwide and pose serious threats to global health. Mucosal vaccination is crucial to combating mucosal pathogens because it enables the immune system to directly target and neutralize pathogens at their point of entry. Mucosal vaccines need to penetrate the mucus layer, reach the target tissue and activate robust immune responses in the mucosal tissues. Material-based strategies are necessary to meet these requirements. In this Review, we provide an overview of current mucosal vaccines, categorized by administration route, to highlight the importance of material design in overcoming the existing delivery challenges. We discuss the different classes of materials currently being used as vaccine carriers to induce antigen-specific mucosal immunity, including lipids, natural and synthetic polymers, inorganic materials and pathogen-inspired materials.
the_role_of_engineered_materials_in_mucosal_vaccination_strategies.pdf
Thompson J, Wang Y, Dreischulte T, Barreiro O, Gonzalez R, Hanč P, Matysiak C, Neely H, Rottenkolber M, Haskell T, et al. Association between Bisphosphonate use and COVID-19 related outcomes. eLife. 2023. Publisher's VersionAbstract

Background: Although there are several efficacious vaccines against COVID-19, vaccination rates in many regions around the world remain insufficient to prevent continued high disease burden and emergence of viral variants. Repurposing of existing therapeutics that prevent or mitigate severe COVID-19 could help to address these challenges. The objective of this study was to determine whether prior use of bisphosphonates is associated with reduced incidence and/or severity of COVID-19.

Methods: A retrospective cohort study utilizing payer-complete health insurance claims data from 8,239,790 patients with continuous medical and prescription insurance January 1, 2019 to June 30, 2020 was performed. The primary exposure of interest was use of any bisphosphonate from January 1, 2019 to February 29, 2020. Bisphosphonate users were identified as patients having at least one bisphosphonate claim during this period, who were then 1:1 propensity score-matched to bisphosphonate non-users by age, gender, insurance type, primary-care-provider visit in 2019, and comorbidity burden. Main outcomes of interest included: (a) any testing for SARS-CoV-2 infection; (b) COVID-19 diagnosis; and (c) hospitalization with a COVID-19 diagnosis between March 1, 2020 and June 30, 2020. Multiple sensitivity analyses were also performed to assess core study outcomes amongst more restrictive matches between BP users/non-users, as well as assessing the relationship between BP-use and other respiratory infections (pneumonia, acute bronchitis) both during the same study period as well as before the COVID outbreak.

Results: 7,906,603 patients for whom continuous medical and prescription insurance information was available were selected. 450,366 bisphosphonate users were identified and 1:1 propensity score-matched to bisphosphonate non-users. Bisphosphonate users had lower odds ratios (OR) of testing for SARS-CoV-2 infection (OR=0.22; 95%CI:0.21-0.23; p<0.001), COVID-19 diagnosis (OR=0.23; 95%CI:0.22-0.24; p<0.001), and COVID-19-related hospitalization (OR=0.26; 95%CI:0.24-0.29; p<0.001). Sensitivity analyses yielded results consistent with the primary analysis. Bisphosphonate-use was also associated with decreased odds of acute bronchitis (OR=0.23; 95%CI:0.22-0.23; p<0.001) or pneumonia (OR=0.32; 95%CI:0.31-0.34; p<0.001) in 2019, suggesting that bisphosphonates may protect against respiratory infections by a variety of pathogens, including but not limited to SARS-CoV-2.

Conclusions: Prior bisphosphonate-use was associated with dramatically reduced odds of SARS-CoV-2 testing, COVID-19 diagnosis, and COVID-19-related hospitalizations. Prospective clinical trials will be required to establish a causal role for bisphosphonate-use in COVID-19-related outcomes.

association_between_bisphosphonate_use_and_covid-19_related_outcomes.pdf elife-79548-supp-v1.zip
Pilato M, Gao Y, Sun Y, Fu A, Grass C, Seeholzer T, Feederle R, Mazo I, Kazer S, Litchfield K, et al. Translational Studies Using the MALT1 Inhibitor (S)-Mepazine to Induce Treg Fragility and Potentiate Immune Checkpoint Therapy in Cancer. J Immunother Precis Oncol. 2023. Publisher's VersionAbstract

Introduction: Regulatory T cells (Tregs) play a critical role in the maintenance of immune homeostasis but also protect tumors from immune-mediated growth control or rejection and pose a significant barrier to effective immunotherapy. Inhibition of MALT1 paracaspase activity can selectively reprogram immune-suppressive Tregs in the tumor microenvironment to adopt a proinflammatory fragile state, which offers an opportunity to impede tumor growth and enhance the efficacy of immune checkpoint therapy (ICT).

Methods: We performed preclinical studies with the orally available allosteric MALT1 inhibitor (S)-mepazine as a single-agent and in combination with anti-programmed cell death protein 1 (PD-1) ICT to investigate its pharmacokinetic properties and antitumor effects in several murine tumor models as well as patient-derived organotypic tumor spheroids (PDOTS).

Results: (S)-mepazine demonstrated significant antitumor effects and was synergistic with anti-PD-1 therapy in vivo and ex vivo but did not affect circulating Treg frequencies in healthy rats at effective doses. Pharmacokinetic profiling revealed favorable drug accumulation in tumors to concentrations that effectively blocked MALT1 activity, potentially explaining preferential effects on tumor-infiltrating over systemic Tregs.

Conclusions: The MALT1 inhibitor (S)-mepazine showed single-agent anticancer activity and presents a promising opportunity for combination with PD-1 pathway-targeted ICT. Activity in syngeneic tumor models and human PDOTS was likely mediated by induction of tumor-associated Treg fragility. This translational study supports ongoing clinical investigations (ClinicalTrials.gov Identifier: NCT04859777) of MPT-0118, (S)-mepazine succinate, in patients with advanced or metastatic treatment-refractory solid tumors.

Keywords: MALT1; cancer immunotherapy; fragile Tregs; interferon-γ; regulatory T cells.

translational_studies_using_the_malt1_inhibitor_s-mepazine_to_induce_treg_fragility_and_potentiate_immune_checkpoint_therapy_in_cancer_.pdf jipo-06-02-02_s03.docx jipo-06-02-02_s01.pptx jipo-06-02-02_s02.pptx
Hanč P, Gonzalez R, Mazo I, Wang Y, Lambert T, Ortiz G, Miller E, von Andrian UH. Multimodal control of dendritic cell functions by nociceptors. Science. 2023.Abstract
It is known that interactions between nociceptors and dendritic cells (DCs) can modulate immune responses in barrier tissues. However, our understanding of the underlying communication frameworks remains rudimentary. Here, we show that nociceptors control DCs in three molecularly distinct ways. First, nociceptors release the calcitonin gene-related peptide that imparts a distinct transcriptional profile on steady-state DCs characterized by expression of pro-interleukin-1β and other genes implicated in DC sentinel functions. Second, nociceptor activation induces contact-dependent calcium fluxes and membrane depolarization in DCs and enhances their production of proinflammatory cytokines when stimulated. Finally, nociceptor-derived chemokine CCL2 contributes to the orchestration of DC-dependent local inflammation and the induction of adaptive responses against skin-acquired antigens. Thus, the combined actions of nociceptor-derived chemokines, neuropeptides, and electrical activity fine-tune DC responses in barrier tissues.
multimodal_control_of_dendritic_cell_functions_by_nociceptors.pdf
Hanč P, Messou M-A, Wang Y, von Andrian UH. Control of myeloid cell functions by nociceptors. Frontiers in Immunology. 2023. Publisher's VersionAbstract
The immune system has evolved to protect the host from infectious agents, parasites, and tumor growth, and to ensure the maintenance of homeostasis. Similarly, the primary function of the somatosensory branch of the peripheral nervous system is to collect and interpret sensory information about the environment, allowing the organism to react to or avoid situations that could otherwise have deleterious effects. Consequently, a teleological argument can be made that it is of advantage for the two systems to cooperate and form an “integrated defense system” that benefits from the unique strengths of both subsystems. Indeed, nociceptors, sensory neurons that detect noxious stimuli and elicit the sensation of pain or itch, exhibit potent immunomodulatory capabilities. Depending on the context and the cellular identity of their communication partners, nociceptors can play both pro- or anti-inflammatory roles, promote tissue repair or aggravate inflammatory damage, improve resistance to pathogens or impair their clearance. In light of such variability, it is not surprising that the full extent of interactions between nociceptors and the immune system remains to be established. Nonetheless, the field of peripheral neuroimmunology is advancing at a rapid pace, and general rules that appear to govern the outcomes of such neuroimmune interactions are beginning to emerge. Thus, in this review, we summarize our current understanding of the interaction between nociceptors and, specifically, the myeloid cells of the innate immune system, while pointing out some of the outstanding questions and unresolved controversies in the field. We focus on such interactions within the densely innervated barrier tissues, which can serve as points of entry for infectious agents and, where known, highlight the molecular mechanisms underlying these interactions.
control_of_myeloid_cell_functions_by_nociceptors.pdf
2022
Stutte S, Ishikawa-Ankerhold H, Lynch L, Eickhoff S, Nasiscionyte S, Guo C, van den Heuvel D, Setzensack D, Colonna M, Maier-Begandt D, et al. High-Fat Diet Rapidly Modifies Trafficking, Phenotype, and Function of Plasmacytoid Dendritic Cells in Adipose Tissue. Immunology. 2022. Publisher's VersionAbstract

Plasmacytoid dendritic cells (pDCs) display an increased abundance in visceral adipose tissue (VAT) of humans with obesity. In the current study, we set out to decipher the molecular mechanisms of their recruitment to VAT and the functional relevance of this process. We observed increased pDC numbers in murine blood, liver, spleen, and VAT after feeding a high-fat diet (HFD) for 3 wk when compared with a standard diet. pDCs were enriched in fat-associated lymphoid clusters representing highly specific lymphoid regions within VAT. HFD led to an enlargement of fat-associated lymphoid clusters with an increased density and migratory speed of pDCs as shown by intravital multiphoton microscopy. For their recruitment into VAT, pDCs employed P-selectin with E-selectin and L-selectin being only critical in response to HFD, indicating that the molecular cues underlying pDC trafficking were dependent on the nutritional state. Subsequent recruitment steps required α4β1 and α4β7 integrins and engagement of CCR7. Application of fingolimod (FTY720) abrogated egress of pDCs from VAT, indicating the involvement of sphingosine-1-phosphate in this process. Furthermore, HFD altered pDC functions by promoting their activation and type 1 IFN expression. Blocking pDC infiltration into VAT prevented weight gain and improved glucose tolerance during HFD. In summary, a HFD fundamentally alters pDC biology by promoting their trafficking, retention, and activation in VAT, which in turn seems to regulate metabolism.

Copyright © 2022 by The American Association of Immunologists, Inc.

high-fat_diet_rapidly_modifies_trafficking_phenotype_and_function_of_plasmacytoid_dendritic_cells_in_adipose_tissue.pdf
Rot A, Gutjahr J, Biswas A, Aslani M, Hub E, Thiriot A, von Andrian UH, Megens R, Weber C, Duchene J. Murine bone marrow macrophages and human monocytes do not express atypical chemokine receptor 1. Cell Stem Cell. 2022.Abstract
No abstract available
murine_bone_marrow_macrophages_and_human_monocytes_do_not_express_atypical_chemokine_receptor_1.pdf
Baldominos P, Barbera-Mourelle A, Barreiro O, Huang Y, Wight A, Cho J, Zhao X, Estivill G, Adam I, Sanchez X, et al. Quiescent cancer cells resist T cell attack by forming an immunosuppressive niche. Cell. 2022;185 (10) :1694-1708. Publisher's VersionAbstract
Immunotherapy is a promising treatment for triple-negative breast cancer (TNBC), but patients relapse, highlighting the need to understand the mechanisms of resistance. We discovered that in primary breast cancer, tumor cells that resist T cell attack are quiescent. Quiescent cancer cells (QCCs) form clusters with reduced immune infiltration. They also display superior tumorigenic capacity and higher expression of chemotherapy resistance and stemness genes. We adapted single-cell RNA-sequencing with precise spatial resolution to profile infiltrating cells inside and outside the QCC niche. This transcriptomic analysis revealed hypoxia-induced programs and identified more exhausted T cells, tumor-protective fibroblasts, and dysfunctional dendritic cells inside clusters of QCCs. This uncovered differential phenotypes in infiltrating cells based on their intra-tumor location. Thus, QCCs constitute immunotherapy-resistant reservoirs by orchestrating a local hypoxic immune-suppressive milieu that blocks T cell function. Eliminating QCCs holds the promise to counteract immunotherapy resistance and prevent disease recurrence in TNBC.
1-s2.0-s0092867422003439-main.pdf
Gonzalez RJ, von Andrian UH. Quo vadis, neutrophil?. Cell. 2022;185 (5) :759-761. Publisher's VersionAbstract
Neutrophil recruitment from blood into tissues is a hallmark of inflammation and anti-microbial host defense. In this issue, De Giovanni et al. describe an unanticipated role for a serotonin metabolite, 5-HIAA, which is produced by activated platelets and mast cells and engages the orphan receptor, GPR35, to recruit neutrophils to inflamed tissues.
quo_vadis_neutrophil.pdf
2021
Marchetti L, Francisco D, Soldati S, Jahromi N, Barcos S, Gruber I, Pareja J, Thiriot A, von Andrian U, Deutsch U, et al. ACKR1 favors transcellular over paracellular T-cell diapedesis across the blood-brain barrier in neuroinflammation in vitro. European Journal of Immunology. 2021.Abstract
The migration of CD4+ effector/memory T cells across the blood-brain barrier (BBB) is a critical step in MS or its animal model, EAE. T-cell diapedesis across the BBB can occur paracellular, via the complex BBB tight junctions or transcellular via a pore through the brain endothelial cell body. Making use of primary mouse brain microvascular endothelial cells (pMBMECs) as in vitro model of the BBB, we here directly compared the transcriptome profile of pMBMECs favoring transcellular or paracellular T-cell diapedesis by RNA sequencing (RNA-seq). We identified the atypical chemokine receptor 1 (Ackr1) as one of the main candidate genes upregulated in pMBMECs favoring transcellular T-cell diapedesis. We confirmed upregulation of ACKR1 protein in pMBMECs promoting transcellular T-cell diapedesis and in venular endothelial cells in the CNS during EAE. Lack of endothelial ACKR1 reduced transcellular T-cell diapedesis across pMBMECs under physiological flow in vitro. Combining our previous observation that endothelial ACKR1 contributes to EAE pathogenesis by shuttling chemokines across the BBB, the present data support that ACKR1 mediated chemokine shuttling enhances transcellular T-cell diapedesis across the BBB during autoimmune neuroinflammation.
_ackr1_favors_transcellular_over_paracellular_t-cell_diapedesis_across_the_blood-brain_barrier_in_neuroinflammation_in_vitro.pdf
Mysore V, Cullere X, Mears J, Rosetti F, Okubo K, Liew PX, Zhang F, Madera-Salcedo I, Rosenbauer F, Stone RM, et al. FcγR engagement reprograms neutrophils into antigen cross-presenting cells that elicit acquired anti-tumor immunity. Nature Communications. 2021.Abstract
Classical dendritic cells (cDC) are professional antigen-presenting cells (APC) that regulate immunity and tolerance. Neutrophil-derived cells with properties of DCs (nAPC) are observed in human diseases and after culture of neutrophils with cytokines. Here we show that FcγR-mediated endocytosis of antibody-antigen complexes or an anti-FcγRIIIB-antigen conjugate converts neutrophils into nAPCs that, in contrast to those generated with cytokines alone, activate T cells to levels observed with cDCs and elicit CD8+ T cell-dependent anti-tumor immunity in mice. Single cell transcript analyses and validation studies implicate the transcription factor PU.1 in neutrophil to nAPC conversion. In humans, blood nAPC frequency in lupus patients correlates with disease. Moreover, anti-FcγRIIIB-antigen conjugate treatment induces nAPCs that can activate autologous T cells when using neutrophils from individuals with myeloid neoplasms that harbor neoantigens or those vaccinated against bacterial toxins. Thus, anti-FcγRIIIB-antigen conjugate-induced conversion of neutrophils to immunogenic nAPCs may represent a possible immunotherapy for cancer and infectious diseases.
fcgr_engagement_reprograms_neutrophils_into_antigen_cross-presenting_cells_that_elicit_acquired_anti-tumor_immunity_supplementary_data.pdf fcgr_engagement_reprograms_neutrophils_into_antigen_cross-presenting_cells_that_elicit_acquired_anti-tumor_immunity_paper.pdf
Vollmann EH, Rattay K, Barreiro O, Thiriot A, Fuhlbrigge RA, Vrbanac V, Kim K-W, Jung S, Tager AM, von Andrian UH. Specialized transendothelial dendritic cells mediate thymic T cell selection against blood-borne macromolecules. Nature Communications. 2021. Publisher's VersionAbstract
T cells undergo rigorous selection in the thymus to ensure self-tolerance and prevent autoimmunity, with this process requiring innocuous self-antigens (Ags) to be presented to thymocytes. Self-Ags are either expressed by thymic stroma cells or transported to the thymus from the periphery by migratory dendritic cells (DCs); meanwhile, small bloodborne peptides can access the thymic parenchyma by diffusing across the vascular lining. Here we describe an additional pathway of thymic Ag acquisition that enables circulating antigenic macromolecules to access both murine and human thymi. This pathway depends on a subset of thymus-resident DCs, distinct from both parenchymal and circulating migratory DCs, that are positioned in immediate proximity to thymic microvessels where they extend cellular processes across the endothelial barrier into the blood stream. Transendothelial positioning of DCs depends on DC-expressed CX3CR1 and its endothelial ligand, CX3CL1, and disrupting this chemokine pathway prevents thymic acquisition of circulating proteins and compromises negative selection of Ag-reactive thymocytes. Thus, transendothelial DCs represent a mechanism by which the thymus can actively acquire blood-borne Ags to induce and maintain central tolerance.
vollmann_et_al-2021-nature_communications.pdf 1.mp4 2.mp4 3.mp4 4.mp4 5.mp4 vollmann_et_al-2021-nature_communications.sup-1.pdf
Barkaway A, Rolas L, Joulia R, Bodkin J, Lenn T, Owen-Woods C, Reglero-Real N, Stein M, Vázquez-Martínez L, Girbl T, et al. Age-related changes in the local milieu of inflamed tissues cause aberrant neutrophil trafficking and subsequent remote organ damage. Immunity. 2021. Publisher's VersionAbstract

Aging is associated with dysregulated immune functions. Here, we investigated the impact of age on neutrophil diapedesis. Using confocal intravital microscopy, we found that in aged mice, neutrophils adhered to vascular endothelium in inflamed tissues but exhibited a high frequency of reverse transendothelial migration (rTEM). This retrograde breaching of the endothelium by neutrophils was governed by enhanced production of the chemokine CXCL1 from mast cells that localized at endothelial cell (EC) junctions. Increased EC expression of the atypical chemokine receptor 1 (ACKR1) supported this pro-inflammatory milieu in aged venules. Accumulation of CXCL1 caused desensitization of the chemokine receptor CXCR2 on neutrophils and loss of neutrophil directional motility within EC junctions. Fluorescent tracking revealed that in aged mice, neutrophils undergoing rTEM re-entered the circulation and disseminated to the lungs where they caused vascular leakage. Thus, neutrophils stemming from a local inflammatory site contribute to remote organ damage, with implication to the dysregulated systemic inflammation associated with aging.

Keywords: ACKR1; CXCR2; Neutrophils; aging; chemokines; diapedesis; endothelium; extravasation; inflammation; mast cells.

age-related_changes_in_the_local_milieu_of_inflamed_tissues_cause_aberrant_neutrophil_trafficking_and_subsequent_remote_organ_damage_paper_and_supp_materials.pdf
Stutte S, Ruf J, Kugler I, Ishikawa-Ankerhold H, Parzefall A, Marconi P, Maeda T, Kaisho T, Krug A, Popper B, et al. Type I interferon mediated induction of somatostatin leads to suppression of ghrelin and appetite thereby promoting viral immunity in mice. Brain Behavior and Immunity. 2021. Publisher's VersionAbstract
Loss of appetite (anorexia) is a typical behavioral response to infectious diseases that often reduces body weight. Also, anorexia can be observed in cancer and trauma patients, causing poor quality of life and reduced prospects of positive therapeutic outcomes. Although anorexia is an acute symptom, its initiation and endocrine regulation during antiviral immune responses are poorly understood. During viral infections, plasmacytoid dendritic cells (pDCs) produce abundant type I interferon (IFN-I) to initiate first-line defense mechanisms. Here, by targeted ablation of pDCs and various in vitro and in vivo mouse models of viral infection and inflammation, we identified that IFN-I is a significant driver of somatostatin (SST). Consequently, SST suppressed the hunger hormone ghrelin that led to severe metabolic changes, anorexia, and rapid body weight loss. Furthermore, during vaccination with Modified Vaccinia Ankara virus (MVA), the SST-mediated suppression of ghrelin was critical to viral immune response, as ghrelin restrained the production of early cytokines by natural killer (NK) cells and pDCs, and impaired the clonal expansion of CD8+ T cells. Thus, the hormonal modulation of ghrelin through SST and the cytokine IFN-I is fundamental for optimal antiviral immunity, which comes at the expense of calorie intake.
Type I interferon mediated induction of somatostatin leads to suppression of ghrelin and appetite thereby promoting viral immunity in mice.pdf Type I interferon mediated induction of somatostatin leads to suppression of ghrelin and appetite thereby promoting viral immunity in mice_Supplementary_Materials.zip
Kochappan R, Cao E, Han S, Hu L, Quach T, Senyschyn D, Ferreira VI, Lee G, Leong N, Sharma G, et al. Targeted delivery of mycophenolic acid to the mesenteric lymph node using a triglyceride mimetic prodrug approach enhances gut-specific immunomodulation in mice. Journal of Controlled Release. 2021;(332) :636-651. Publisher's VersionAbstract
The mesenteric lymph nodes (MLN) are a key site for the generation of adaptive immune responses to gut-derived antigenic material and immune cells within the MLN contribute to the pathophysiology of a range of conditions including inflammatory and autoimmune diseases, viral infections, graft versus host disease and cancer. Tar-geting immunomodulating drugs to the MLN may thus be beneficial in a range of conditions. This paper in-vestigates the potential benefit of targeting a model immunosuppressant drug, mycophenolic acid (MPA), to T cells in the MLN, using a triglyceride (TG) mimetic prodrug approach. We confirmed that administration of MPA in the TG prodrug form (MPA-TG), increased lymphatic transport of MPA-related species 83-fold and increased MLN concentrations of MPA >20 fold, when compared to MPA alone, for up to 4 h in mice. At the same time, the plasma exposure of MPA and MPA-TG was similar, limiting the opportunity for systemic side effects. Confocal microscopy and flow cytometry studies with a fluorescent model prodrug (Bodipy-TG) revealed that the prodrug accumulated in the MLN cortex and paracortex at 5 and 10 h following administration and was highly associated with B cells and T cells that are found in these regions of the MLN. Finally, we demonstrated that MPA-TG was significantly more effective than MPA at inhibiting CD4+and CD8+T cell proliferation in the MLN of mice in response to  an  oral ovalbumin antigen challenge. In  contrast, MPA-TG was no  more effective than MPA at inhibiting T cell proliferation in peripheral LN when mice were challenged via SC administration of ovalbumin. This paper provides the first evidence of an in vivo pharmacodynamic benefit of targeting the MLN using a TG mimetic prodrug approach. The TG mimetic prodrug technology has the potential to benefit the treatment of a range of conditions where aberrant immune responses are initiated in gut-associated lymphoid tissues.
Targeted delivery of mycophenolic acid to the mesenteric lymph node using a triglyceride mimetic prodrug approach enhances gut-specific immunomodulation in mice.pdf Targeted delivery of mycophenolic acid to the mesenteric lymph node using a triglyceride mimetic prodrug approach enhances gut-specific immunomodulation in mice_Supplementary_Material..docx
von Andrian UH. NK cell memory: discovery of a mystery. Nature Immunology. 2021.Abstract
Ulrich von Andrian recounts how an unexpected experimental result called into question a well-established concept in immunology: the mechanism of immune memory. Follow-up experiments revealed that NK cells can mediate antigen-specific adaptive immune responses.
nk_cell_memory-_discovery_of_a_mystery.pdf
Huang S, Ziegler C, Austin J, Mannoun N, Vukovic M, Ordovas-Montanes J, Shalek A, von Andrian UH. Lymph nodes are innervated by a unique population of sensory neurons with immunomodulatory potential. Cell. 2021;184 (2) :441-459. Publisher's VersionAbstract
Immune responses within barrier tissues are regulated, in part, by nociceptors, specialized peripheral sensory neurons that detect noxious stimuli. Previous work has shown that nociceptor ablation not only alters local responses to immune challenge at peripheral sites, but also within draining lymph nodes (LNs). The mechanisms and significance of nociceptor-dependent modulation of LN function are unknown. Indeed, although sympathetic innervation of LNs is well documented, it has been unclear whether the LN parenchyma itself is innervated by sensory neurons. Here, using a combination of high-resolution imaging, retrograde viral tracing, single-cell transcriptomics (scRNA-seq), and optogenetics, we identified and functionally tested a sensory neuro-immune circuit that is preferentially located in the outermost cortex of skin-draining LNs. Transcriptomic profiling revealed that there are at least four discrete subsets of sensory neurons that innervate LNs with a predominance of peptidergic nociceptors, and an innervation pattern that is distinct from that in the surrounding skin. To uncover potential LN-resident communication partners for LN-innervating sensory neurons, we employed scRNA-seq to generate a draft atlas of all murine LN cells and, based on receptor-ligand expression patterns, nominated candidate target populations among stromal and immune cells. Using selective optogenetic stimulation of LN-innervating sensory axons, we directly experimentally tested our inferred connections. Acute neuronal activation triggered rapid transcriptional changes preferentially within our top-ranked putative interacting partners, principally endothelium and other nodal stroma cells, as well as several innate leukocyte populations. Thus, LNs are monitored by a unique population of sensory neurons that possesses immunomodulatory potential.
Lymph nodes are innervated by a unique population of sensory neurons with immunomodulatory potential.pdf Lymph nodes are innervated by a unique population of sensory neurons with immunomodulatory potential_Supplementary_Materials.zip
2020
Helble JD, Gonzalez RJ, von Andrian UH, Starnbach MN. Gamma Interferon Is Required for Chlamydia Clearance but Is Dispensable for T Cell Homing to the Genital Tract. American Society for Microbiology. 2020. Publisher's VersionAbstract

While there is no effective vaccine against Chlamydia trachomatis infection, previous work has demonstrated the importance of C. trachomatis-specific CD4+ T cells (NR1 T cells) in pathogen clearance. Specifically, NR1 T cells have been shown to be protective in mice, and this protection depends on the host's ability to sense the cytokine gamma interferon (IFN-γ). However, it is unclear what role NR1 production or sensing of IFN-γ plays in T cell homing to the genital tract or T cell-mediated protection against C. trachomatis Using two-photon microscopy and flow cytometry, we found that naive wild-type (WT), IFN-γ-/-, and IFN-γR-/- NR1 T cells specifically home to sections in the genital tract that contain C. trachomatis We also determined that protection against infection requires production of IFN-γ from either NR1 T cells or endogenous cells, further highlighting the importance of IFN-γ in clearing C. trachomatis infection.IMPORTANCE Chlamydia trachomatis is an important mucosal pathogen that is the leading cause of sexually transmitted bacterial infections in the United States. Despite this, there is no vaccine currently available. In order to develop such a vaccine, it is necessary to understand the components of the immune response that can lead to protection against this pathogen. It is well known that antigen-specific CD4+ T cells are critical for Chlamydia clearance, but the contexts in which they are protective or not protective are unknown. Here, we aimed to characterize the importance of gamma interferon production and sensing by T cells and the effects on the immune response to C. trachomatis Our work here helps to define the contexts in which antigen-specific T cells can be protective, which is critical to our ability to design an effective and protective vaccine against C. trachomatis.

Keywords: Chlamydia; IFN-γ; T cells; genital tract immunity; interferons; mucosal immunity; mucosal pathogens.

Gamma Interferon Is Required for Chlamydia Clearance but Is Dispensable for T Cell Homing to the Genital Tract.pdf
Perro M, Iannacone M, von Andrian UH, Peixoto A. Role of LFA-1 integrin in the control of a lymphocytic choriomeningitis virus (LCMV) infection. Virulence. 2020 :1640-1655. Publisher's VersionAbstract
Leukocyte function-associated antigen 1 (LFA-1) is the most widely expressed member of the β2 integrin family of cell-cell adhesion molecules. Although LFA-1 is thought to regulate multiple aspects of T cell immunity, its role in the response of CD8+ T cells to viral infections remains unclear. Indeed, compelling clinical evidence shows that loss of LFA-1 function predisposes to infection in humans but animal models show limited to no susceptibility to infection. Here, we addressed this conundrum in a mouse model of infection with lymphocytic choriomeningitis virus (LCMV), where CD8+ T cells are necessary and sufficient to confer protection. To this end, we followed the fate and function of wild-type and LFA-1 deficient virus-specific CD8+ T cells and assessed the effect of blocking anti-LFA-1 monoclonal antibody in the outcome of infection. Our analysis of viral clearance and T cell responses using transcriptome profiling reveals a role for LFA-1 as a gatekeeper of effector T cell survival and dysfunction that when defective can predispose to LCMV infection.
Role of LFA-1 integrin in the control of a lymphocytic choriomeningitis virus (LCMV) infection.pdf Role of LFA-1 integrin in the control of a lymphocytic choriomeningitis virus (LCMV) infection_Supplementary_Materials.docx
Zeng J, Eljalby M, Aryal R, Lehoux S, Stavenhagen K, Kudelka M, Wang Y, Wang J, Ju T, von Andrian UH, et al. Cosmc controls B cell homing. Nature Communications. 2020;11 (3990).Abstract
The molecular mechanisms regulating lymphocyte homing into lymph nodes are only partly understood. Here, we report that B cell-specific deletion of the X-linked gene, Cosmc, and the consequent decrease of protein O-glycosylation, induces developmental blocks of mouse B cells. After transfer into wild-type recipient, Cosmc-null B cells fail to home to lymph nodes as well as non-lymphoid organs. Enzymatic desialylation of wild-type B cells blocks their migration into lymph nodes, indicating a requirement of sialylated O-glycans for proper trafficking. Mechanistically, Cosmc-deficient B cells have normal rolling and firm arrest on high endothelium venules (HEV), thereby attributing their inefficient trafficking to alterations in the subsequent transendothelial migration step. Finally, Cosmc-null B cells have defective chemokine signaling responses. Our results thus demonstrate that Cosmc and its effects on O-glycosylation are important for controlling B cell homing.
Cosmc controls B cell homing.pdf Cosmc controls B cell homing_Supplementary Movie 1.mp4 Cosmc controls B cell homing_Supplementary Movie 2.mp4

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