Publications

2016
Mingozzi F, Spreafico R, Gorletta T, Cigni C, Di Gioia M, Caccia M, Sironi L, Collini M, Soncini M, Rusconi M, et al. Prolonged contact with dendritic cells turns lymph node-resident NK cells into anti-tumor effectors. EMBO Mol Med. 2016;8 (9) :1039-51.Abstract
Natural killer (NK) cells are critical players against tumors. The outcome of anti-tumor vaccination protocols depends on the efficiency of NK-cell activation, and efforts are constantly made to manipulate them for immunotherapeutic approaches. Thus, a better understanding of NK-cell activation dynamics is needed. NK-cell interactions with accessory cells and trafficking between secondary lymphoid organs and tumoral tissues remain poorly characterized. Here, we show that upon triggering innate immunity with lipopolysaccharide (LPS), NK cells are transiently activated, leave the lymph node, and infiltrate the tumor, delaying its growth. Interestingly, NK cells are not actively recruited at the draining lymph node early after LPS administration, but continue their regular homeostatic turnover. Therefore, NK cells resident in the lymph node at the time of LPS administration become activated and exert anti-tumor functions. NK-cell activation correlates with the establishment of prolonged interactions with dendritic cells (DCs) in lymph nodes, as observed by two-photon microscopy. Close DC and NK-cell contacts are essential for the localized delivery of DC-derived IL-18 to NK cells, a strict requirement in NK-cell activation.
embo_mol_med_-_2016_-_mingozzi_-_prolonged_contact_with_dendritic_cells_turns_lymph_node-resident_nk_cells_into_anti-tumor.pdf emmm201506164-sup-0003-movieev2.zip emmm201506164-sup-0004-movieev3.zip emmm201506164-sup-0007-movieev6.zip emmm201506164-sup-0005-movieev4.zip emmm201506164-sup-0002-movieev1.zip emmm201506164-sup-0006-movieev5.zip
Pucci F, Garris C, Lai CP, Newton A, Pfirschke C, Engblom C, Alvarez D, Sprachman M, Evavold C, Magnuson A, et al. SCS macrophages suppress melanoma by restricting tumor-derived vesicle-B cell interactions. Science. 2016;352 (6282) :242-6.Abstract
Tumor-derived extracellular vesicles (tEVs) are important signals in tumor-host cell communication, yet it remains unclear how endogenously produced tEVs affect the host in different areas of the body. We combined imaging and genetic analysis to track melanoma-derived vesicles at organismal, cellular, and molecular scales to show that endogenous tEVs efficiently disseminate via lymphatics and preferentially bind subcapsular sinus (SCS) CD169(+) macrophages in tumor-draining lymph nodes (tdLNs) in mice and humans. The CD169(+) macrophage layer physically blocks tEV dissemination but is undermined during tumor progression and by therapeutic agents. A disrupted SCS macrophage barrier enables tEVs to enter the lymph node cortex, interact with B cells, and foster tumor-promoting humoral immunity. Thus, CD169(+) macrophages may act as tumor suppressors by containing tEV spread and ensuing cancer-enhancing immunity.
science.aaf1328_01.pdf pucci.sm_.pdf
Azzi J, Yin Q, Uehara M, Ohori S, Tang L, Cai K, Ichimura T, McGrath M, Maarouf O, Kefaloyianni E, et al. Targeted Delivery of Immunomodulators to Lymph Nodes. Cell Rep. 2016;15 (6) :1202-13.Abstract
Active-targeted delivery to lymph nodes represents a major advance toward more effective treatment of immune-mediated disease. The MECA79 antibody recognizes peripheral node addressin molecules expressed by high endothelial venules of lymph nodes. By mimicking lymphocyte trafficking to the lymph nodes, we have engineered MECA79-coated microparticles containing an immunosuppressive medication, tacrolimus. Following intravenous administration, MECA79-bearing particles showed marked accumulation in the draining lymph nodes of transplanted animals. Using an allograft heart transplant model, we show that targeted lymph node delivery of microparticles containing tacrolimus can prolong heart allograft survival with negligible changes in tacrolimus serum level. Using MECA79 conjugation, we have demonstrated targeted delivery of tacrolimus to the lymph nodes following systemic administration, with the capacity for immune modulation in vivo.
sciencedirect_files_29mar2023_18-23-50.352.zip 1-s2.0-s2211124716304065-main.pdf
2015
Reeves KR, Li H, Jost S, Blass E, Li H, Schafer JL, Varner V, Manickam C, Eslamizar L, Altfeld M, et al. Antigen-specific NK cell memory in rhesus macaques. Nat Immunol. 2015;16 (9) :927-32.Abstract
Natural killer (NK) cells have traditionally been considered nonspecific components of innate immunity, but recent studies have shown features of antigen-specific memory in mouse NK cells. However, it has remained unclear whether this phenomenon also exists in primates. We found that splenic and hepatic NK cells from SHIV(SF162P3)-infected and SIV(mac251)-infected macaques specifically lysed Gag- and Env-pulsed dendritic cells in an NKG2-dependent fashion, in contrast to NK cells from uninfected macaques. Moreover, splenic and hepatic NK cells from Ad26-vaccinated macaques efficiently lysed antigen-matched but not antigen-mismatched targets 5 years after vaccination. These data demonstrate that robust, durable, antigen-specific NK cell memory can be induced in primates after both infection and vaccination, and this finding could be important for the development of vaccines against HIV-1 and other pathogens.
nihms700727.pdf
Hu K, Harris DL, Yamaguchi T, von Andrian UH, Hamrah P. A Dual Role for Corneal Dendritic Cells in Herpes Simplex Keratitis: Local Suppression of Corneal Damage and Promotion of Systemic Viral Dissemination. PLoS One. 2015;10 (9) :e0137123.Abstract
The cornea is the shield to the foreign world and thus, a primary site for peripheral infections. However, transparency and vision are incompatible with inflammation and scarring that may result from infections. Thus, the cornea is required to perform a delicate balance between fighting infections and preserving vision. To date, little is known about the specific role of antigen-presenting cells in viral keratitis. In this study, utilizing an established murine model of primary acute herpes simplex virus (HSV)-1 keratitis, we demonstrate that primary HSV keratitis results in increased conventional dendritic cells (cDCs) and macrophages within 24 hours after infection. Local depletion of cDCs in CD11c-DTR mice by subconjuntival diphtheria toxin injections, led to increased viral proliferation, and influx of inflammatory cells, resulting in increased scarring and clinical keratitis. In addition, while HSV infection resulted in significant corneal nerve destruction, local depletion of cDCs resulted in a much more severe loss of corneal nerves. Further, local cDC depletion resulted in decreased corneal nerve infection, and subsequently decreased and delayed systemic viral transmission in the trigeminal ganglion and draining lymph node, resulting in decreased mortality of mice. In contrast, sham depletion or depletion of macrophages through local injection of clodronate liposomes had neither a significant impact on the cornea, nor an effect on systemic viral transmission. In conclusion, we demonstrate that corneal cDCs may play a primary role in local corneal defense during viral keratitis and preserve vision, at the cost of inducing systemic viral dissemination, leading to increased mortality.
paper_dual_role_corneal.pdf s1_movie.avi
Sharei A, Trifonova R, Jhunjhunwala S, Hartoularos GC, Eyerman AT, Lytton-Jean A, Angin M, Sharma S, Poceviciute R, Mao S, et al. Ex vivo cytosolic delivery of functional macromolecules to immune cells. PLoS One. 2015;10 (4) :e0118803.Abstract
Intracellular delivery of biomolecules, such as proteins and siRNAs, into primary immune cells, especially resting lymphocytes, is a challenge. Here we describe the design and testing of microfluidic intracellular delivery systems that cause temporary membrane disruption by rapid mechanical deformation of human and mouse immune cells. Dextran, antibody and siRNA delivery performance is measured in multiple immune cell types and the approach's potential to engineer cell function is demonstrated in HIV infection studies.
ex_vivo_cytosolic_delivery_of_functional_macromolecules_to_immune_cells.pdf
Gerlach C, Loughhead SM, von Andrian UH. Figuring fact from fiction: unbiased polling of memory T cells. Cell. 2015;161 (4) :702-4.Abstract
Immunization generates several memory T cell subsets that differ in their migratory properties, anatomic distribution, and, hence, accessibility to investigation. In this issue, Steinert et al. demonstrate that what was believed to be a minor memory cell subset in peripheral tissues has been dramatically underestimated. Thus, current models of protective immunity require revision.
1-s2.0-s0092867415004948-main.pdf
Geva-Zatorsky N, Alvarez D, Hudak JE, Reading NC, Erturk-Hasdemir D, Dasgupta S, von Andrian UH, Kasper DL. In vivo imaging and tracking of host-microbiota interactions via metabolic labeling of gut anaerobic bacteria. Nat Med. 2015;21 (9) :1091-100.Abstract
The intestine is densely populated by anaerobic commensal bacteria. These microorganisms shape immune system development, but understanding of host-commensal interactions is hampered by a lack of tools for studying the anaerobic intestinal environment. We applied metabolic oligosaccharide engineering and bioorthogonal click chemistry to label various commensal anaerobes, including Bacteroides fragilis, a common and immunologically important commensal. We studied the dissemination of B. fragilis after acute peritonitis and characterized the interactions of the intact microbe and its polysaccharide components in myeloid and B cell lineages. We were able to assess the distribution and colonization of labeled B. fragilis along the intestine, as well as niche competition after coadministration of multiple species of the microbiota. We also fluorescently labeled nine additional commensals (eight anaerobic and one microaerophilic) from three phyla common in the gut--Bacteroidetes, Firmicutes and Proteobacteria--as well as one aerobic pathogen (Staphylococcus aureus). This strategy permits visualization of the anaerobic microbial niche by various methods, including intravital two-photon microscopy and non-invasive whole-body imaging, and can be used to study microbial colonization and host-microbe interactions in real time.
nihms726452-supplement-supp_mat_.pdf nihms726452.pdf
Jhunjhunwala S, Aresta-DaSilva S, Tang K, Alvarez D, Webber MJ, Tang BC, Lavin DM, Veiseh O, Doloff JC, Bose S, et al. Neutrophil Responses to Sterile Implant Materials. PLoS One. 2015;10 (9) :e0137550.Abstract
In vivo implantation of sterile materials and devices results in a foreign body immune response leading to fibrosis of implanted material. Neutrophils, one of the first immune cells to be recruited to implantation sites, have been suggested to contribute to the establishment of the inflammatory microenvironment that initiates the fibrotic response. However, the precise numbers and roles of neutrophils in response to implanted devices remains unclear. Using a mouse model of peritoneal microcapsule implantation, we show 30-500 fold increased neutrophil presence in the peritoneal exudates in response to implants. We demonstrate that these neutrophils secrete increased amounts of a variety of inflammatory cytokines and chemokines. Further, we observe that they participate in the foreign body response through the formation of neutrophil extracellular traps (NETs) on implant surfaces. Our results provide new insight into neutrophil function during a foreign body response to peritoneal implants which has implications for the development of biologically compatible medical devices.
neutrophil_responses_to_sterile_implant_materials.pdf
Maldonado RA, LaMothe RA, Ferrari JD, Zhang A-H, Rossi RJ, Kolte PN, Griset AP, O'Neil C, Altreuter DH, Browning E, et al. Polymeric synthetic nanoparticles for the induction of antigen-specific immunological tolerance. Proc Natl Acad Sci U S A. 2015;112 (2) :E156-65.Abstract
Current treatments to control pathological or unwanted immune responses often use broadly immunosuppressive drugs. New approaches to induce antigen-specific immunological tolerance that control both cellular and humoral immune responses are desirable. Here we describe the use of synthetic, biodegradable nanoparticles carrying either protein or peptide antigens and a tolerogenic immunomodulator, rapamycin, to induce durable and antigen-specific immune tolerance, even in the presence of potent Toll-like receptor agonists. Treatment with tolerogenic nanoparticles results in the inhibition of CD4+ and CD8+ T-cell activation, an increase in regulatory cells, durable B-cell tolerance resistant to multiple immunogenic challenges, and the inhibition of antigen-specific hypersensitivity reactions, relapsing experimental autoimmune encephalomyelitis, and antibody responses against coagulation factor VIII in hemophilia A mice, even in animals previously sensitized to antigen. Only encapsulated rapamycin, not the free form, could induce immunological tolerance. Tolerogenic nanoparticle therapy represents a potential novel approach for the treatment of allergies, autoimmune diseases, and prevention of antidrug antibodies against biologic therapies.
pnas.1408686111.pdf pnas.201408686si.pdf
Ordovas-Montanes J, Rakoff-Nahoum S, Huang S, Riol-Blanco L, Barreiro O, von Andrian UH. The Regulation of Immunological Processes by Peripheral Neurons in Homeostasis and Disease. Trends Immunol. 2015;36 (10) :578-604.Abstract
The nervous system and the immune system are the principal sensory interfaces between the internal and external environment. They are responsible for recognizing, integrating, and responding to varied stimuli, and have the capacity to form memories of these encounters leading to learned or 'adaptive' future responses. We review current understanding of the cross-regulation between these systems. The autonomic and somatosensory nervous systems regulate both the development and deployment of immune cells, with broad functions that impact on hematopoiesis as well as on priming, migration, and cytokine production. In turn, specific immune cell subsets contribute to homeostatic neural circuits such as those controlling metabolism, hypertension, and the inflammatory reflex. We examine the contribution of the somatosensory system to autoimmune, autoinflammatory, allergic, and infectious processes in barrier tissues and, in this context, discuss opportunities for therapeutic manipulation of neuro-immune interactions.
1-s2.0-s1471490615001994-main.pdf
Lynch L, Michelet X, Zhang S, Brennan PJ, Moseman A, Lester C, Besra G, Vomhof-Dekrey EE, Tighe M, Koay H-F, et al. Regulatory iNKT cells lack expression of the transcription factor PLZF and control the homeostasis of T(reg) cells and macrophages in adipose tissue. Nat Immunol. 2015;16 (1) :85-95.Abstract
Invariant natural killer T cells (iNKT cells) are lipid-sensing innate T cells that are restricted by the antigen-presenting molecule CD1d and express the transcription factor PLZF. iNKT cells accumulate in adipose tissue, where they are anti-inflammatory, but the factors that contribute to their anti-inflammatory nature, as well as their targets in adipose tissue, are unknown. Here we found that iNKT cells in adipose tissue had a unique transcriptional program and produced interleukin 2 (IL-2) and IL-10. Unlike other iNKT cells, they lacked PLZF but expressed the transcription factor E4BP4, which controlled their IL-10 production. The adipose iNKT cells were a tissue-resident population that induced an anti-inflammatory phenotype in macrophages and, through the production of IL-2, controlled the number, proliferation and suppressor function of regulatory T cells (Treg cells) in adipose tissue. Thus, iNKT cells in adipose tissue are unique regulators of immunological homeostasis in this tissue.
nihms640826.pdf
Pang P, Jin X, Proctor BM, Farley M, Roy N, Chin MS, von Andrian UH, Vollmann E, Perro M, Hoffman RJ, et al. RGS4 inhibits angiotensin II signaling and macrophage localization during renal reperfusion injury independent of vasospasm. Kidney Int. 2015;87 (4) :771-83.Abstract
Vascular inflammation is a major contributor to the severity of acute kidney injury. In the context of vasospasm-independent reperfusion injury we studied the potential anti-inflammatory role of the Gα-related RGS protein, RGS4. Transgenic RGS4 mice were resistant to 25 min injury, although post-ischemic renal arteriolar diameter was equal to the wild type early after injury. A 10 min unilateral injury was performed to study reperfusion without vasospasm. Eighteen hours after injury, blood flow was decreased in the inner cortex of wild-type mice with preservation of tubular architecture. Angiotensin II levels in the kidneys of wild-type and transgenic mice were elevated in a sub-vasoconstrictive range 12 and 18 h after injury. Angiotensin II stimulated pre-glomerular vascular smooth muscle cells (VSMCs) to secrete the macrophage chemoattractant RANTES, a process decreased by angiotensin II R2 (AT2) inhibition. However, RANTES increased when RGS4 expression was suppressed implicating Gα protein activation in an AT2-RGS4-dependent pathway. RGS4 function, specific to VSMC, was tested in a conditional VSMC-specific RGS4 knockout showing high macrophage density by T2 MRI compared with transgenic and non-transgenic mice after the 10 min injury. Arteriolar diameter of this knockout was unchanged at successive time points after injury. Thus, RGS4 expression, specific to renal VSMC, inhibits angiotensin II-mediated cytokine signaling and macrophage recruitment during reperfusion, distinct from vasomotor regulation.
1-s2.0-s0085253815302118-main.pdf
Stary G, Olive A, Radovic-Moreno AF, Gondek D, Alvarez D, Basto PA, Perro M, Vrbanac VD, Tager AM, Shi J, et al. VACCINES. A mucosal vaccine against Chlamydia trachomatis generates two waves of protective memory T cells. Science. 2015;348 (6241) :aaa8205.Abstract
Genital Chlamydia trachomatis (Ct) infection induces protective immunity that depends on interferon-γ-producing CD4 T cells. By contrast, we report that mucosal exposure to ultraviolet light (UV)-inactivated Ct (UV-Ct) generated regulatory T cells that exacerbated subsequent Ct infection. We show that mucosal immunization with UV-Ct complexed with charge-switching synthetic adjuvant particles (cSAPs) elicited long-lived protection in conventional and humanized mice. UV-Ct-cSAP targeted immunogenic uterine CD11b(+)CD103(-) dendritic cells (DCs), whereas UV-Ct accumulated in tolerogenic CD11b(-)CD103(+) DCs. Regardless of vaccination route, UV-Ct-cSAP induced systemic memory T cells, but only mucosal vaccination induced effector T cells that rapidly seeded uterine mucosa with resident memory T cells (T(RM) cells). Optimal Ct clearance required both T(RM) seeding and subsequent infection-induced recruitment of circulating memory T cells. Thus, UV-Ct-cSAP vaccination generated two synergistic memory T cell subsets with distinct migratory properties.
nihms-726437_01.pdf stary.sm_.pdf
2014
Ilyinskii PO, Roy CJ, O'Neil CP, Browning EA, Pittet LA, Altreuter DH, Alexis F, Tonti E, Shi J, Basto PA, et al. Adjuvant-carrying synthetic vaccine particles augment the immune response to encapsulated antigen and exhibit strong local immune activation without inducing systemic cytokine release. Vaccine. 2014;32 (24) :2882-95.Abstract
Augmentation of immunogenicity can be achieved by particulate delivery of an antigen and by its co-administration with an adjuvant. However, many adjuvants initiate strong systemic inflammatory reactions in vivo, leading to potential adverse events and safety concerns. We have developed a synthetic vaccine particle (SVP) technology that enables co-encapsulation of antigen with potent adjuvants. We demonstrate that co-delivery of an antigen with a TLR7/8 or TLR9 agonist in synthetic polymer nanoparticles results in a strong augmentation of humoral and cellular immune responses with minimal systemic production of inflammatory cytokines. In contrast, antigen encapsulated into nanoparticles and admixed with free TLR7/8 agonist leads to lower immunogenicity and rapid induction of high levels of inflammatory cytokines in the serum (e.g., TNF-a and IL-6 levels are 50- to 200-fold higher upon injection of free resiquimod (R848) than of nanoparticle-encapsulated R848). Conversely, local immune stimulation as evidenced by cellular infiltration of draining lymph nodes and by intranodal cytokine production was more pronounced and persisted longer when SVP-encapsulated TLR agonists were used. The strong local immune activation achieved using a modular self-assembling nanoparticle platform markedly enhanced immunogenicity and was equally effective whether antigen and adjuvant were co-encapsulated in a single nanoparticle formulation or co-delivered in two separate nanoparticles. Moreover, particle encapsulation enabled the utilization of CpG oligonucleotides with the natural phosphodiester backbone, which are otherwise rapidly hydrolyzed by nucleases in vivo. The use of SVP may enable clinical use of potent TLR agonists as vaccine adjuvants for indications where cellular immunity or robust humoral responses are required.
1-s2.0-s0264410x1400200x-main.pdf
Sage PT, Alvarez D, Godec J, von Andrian UH, Sharpe AH. Circulating T follicular regulatory and helper cells have memory-like properties. J Clin Invest. 2014;124 (12) :5191-204.Abstract
Follicular Tregs (Tfr cells) inhibit antibody production, whereas follicular Th cells (Tfh cells) stimulate it. Tfr cells are found in blood; however, relatively little is known about the developmental signals for these cells or their functions. Here we demonstrated that circulating Tfr and Tfh cells share properties of memory cells and are distinct from effector Tfr and Tfh cells found within lymph nodes (LNs). Circulating memory-like Tfh cells were potently reactivated by DCs, homed to germinal centers, and produced more cytokines than did effector LN Tfh cells. Circulating memory-like Tfr cells persisted for long periods of time in vivo and homed to germinal centers after reactivation. Effector LN Tfr cells suppressed Tfh cell activation and production of cytokines, including IL-21, and inhibited class switch recombination and B cell activation. The suppressive function of this population was not dependent on specific antigen. Similar to LN effector Tfr cells, circulating Tfr cells also suppressed B and Tfh cells, but with a much lower capacity. Our data indicate that circulating memory-like Tfr cells are less suppressive than LN Tfr cells and circulating memory-like Tfh cells are more potent than LN effector Tfh cells; therefore, these circulating populations can provide rapid and robust systemic B cell help during secondary antigen exposure.
76861.2-20201218131625-covered-e0fd13ba177f913fd3156f593ead4cfd.pdf
Dahlman JE, Barnes C, Khan O, Thiriot A, Jhunjunwala S, Shaw TE, Xing Y, Sager HB, Sahay G, Speciner L, et al. In vivo endothelial siRNA delivery using polymeric nanoparticles with low molecular weight. Nat Nanotechnol. 2014;9 (8) :648-655.Abstract

Dysfunctional endothelium contributes to more diseases than any other tissue in the body. Small interfering RNAs (siRNAs) can help in the study and treatment of endothelial cells in vivo by durably silencing multiple genes simultaneously, but efficient siRNA delivery has so far remained challenging. Here, we show that polymeric nanoparticles made of low-molecular-weight polyamines and lipids can deliver siRNA to endothelial cells with high efficiency, thereby facilitating the simultaneous silencing of multiple endothelial genes in vivo. Unlike lipid or lipid-like nanoparticles, this formulation does not significantly reduce gene expression in hepatocytes or immune cells even at the dosage necessary for endothelial gene silencing. These nanoparticles mediate the most durable non-liver silencing reported so far and facilitate the delivery of siRNAs that modify endothelial function in mouse models of vascular permeability, emphysema, primary tumour growth and metastasis.

nn14

Cover Art by Aude Thiriot

nihms-577487.pdf
Millet YA, Alvarez D, Ringgaard S, von Andrian UH, Davis BM, Waldor MK. Insights into Vibrio cholerae intestinal colonization from monitoring fluorescently labeled bacteria. PLoS Pathog. 2014;10 (10) :e1004405.Abstract
Vibrio cholerae, the agent of cholera, is a motile non-invasive pathogen that colonizes the small intestine (SI). Most of our knowledge of the processes required for V. cholerae intestinal colonization is derived from enumeration of wt and mutant V. cholerae recovered from orogastrically infected infant mice. There is limited knowledge of the distribution of V. cholerae within the SI, particularly its localization along the villous axis, or of the bacterial and host factors that account for this distribution. Here, using confocal and intravital two-photon microscopy to monitor the localization of fluorescently tagged V. cholerae strains, we uncovered unexpected and previously unrecognized features of V. cholerae intestinal colonization. Direct visualization of the pathogen within the intestine revealed that the majority of V. cholerae microcolonies attached to the intestinal epithelium arise from single cells, and that there are notable regiospecific aspects to V. cholerae localization and factors required for colonization. In the proximal SI, V. cholerae reside exclusively within the developing intestinal crypts, but they are not restricted to the crypts in the more distal SI. Unexpectedly, V. cholerae motility proved to be a regiospecific colonization factor that is critical for colonization of the proximal, but not the distal, SI. Furthermore, neither motility nor chemotaxis were required for proper V. cholerae distribution along the villous axis or in crypts, suggesting that yet undefined processes enable the pathogen to find its niches outside the intestinal lumen. Finally, our observations suggest that host mucins are a key factor limiting V. cholerae intestinal colonization, particularly in the proximal SI where there appears to be a more abundant mucus layer. Collectively, our findings demonstrate the potent capacity of direct pathogen visualization during infection to deepen our understanding of host pathogen interactions.
insights_into_vibrio_cholerae_intestinal_colonization_from_monitoring_fluorescently_labeled_bacteria.pdf video_s1.mov video_s2.mov
Kumar L, Chou J, Yee CSK, Borzutzky A, Vollmann EH, von Andrian UH, Park S-Y, Hollander G, Manis JP, Poliani LP, et al. Leucine-rich repeat containing 8A (LRRC8A) is essential for T lymphocyte development and function. J Exp Med. 2014;211 (5) :929-42.Abstract
Lrrc8a is a ubiquitously expressed gene that encodes a leucine-rich repeat (LRR)-containing protein detected at higher levels on the surface of thymocytes than on other immune cells. We generated Lrrc8a(-/-) mice to investigate the role of LRRC8A in lymphocyte development and function. Lrrc8a(-/-) mice had increased prenatal and postnatal mortality, growth retardation, and multiple tissue abnormalities. Lrrc8a(-/-) mice displayed a modest block in B cell development but intact intrinsic B cell function. In contrast, both Lrrc8a(-/-) mice and Lrrc8a(-/-)→Rag2(-/-) bone marrow chimeras exhibited a severe cell-intrinsic block in early thymic development, with decreased proliferation and increased apoptosis of thymocytes, and impaired peripheral T cell function. Thymic epithelial cells expressed an LRRC8A ligand that was critical for double-negative to double-positive thymocyte differentiation and survival in vitro. LRRC8A constitutively associated with the GRB2-GAB2 complex and lymphocyte-specific protein tyrosine kinase (LCK) in thymocytes. LRRC8A ligation activated AKT via the LCK-ZAP-70-GAB2-PI3K pathway, and AKT phosphorylation was markedly reduced in the thymus of Lrrc8a(-/-) mice. These findings reveal an essential role for LRRC8A in T cell development, survival, and function.
jem_20131379_sm.pdf jem_20131379.pdf
Riol-Blanco L, Ordovas-Montanes J, Perro M, Naval E, Thiriot A, Alvarez D, Paust S, Wood JN, von Andrian UH. Nociceptive sensory neurons drive interleukin-23-mediated psoriasiform skin inflammation. Nature. 2014;510 (7503) :157-61.Abstract
The skin has a dual function as a barrier and a sensory interface between the body and the environment. To protect against invading pathogens, the skin harbours specialized immune cells, including dermal dendritic cells (DDCs) and interleukin (IL)-17-producing γδ T (γδT17) cells, the aberrant activation of which by IL-23 can provoke psoriasis-like inflammation. The skin is also innervated by a meshwork of peripheral nerves consisting of relatively sparse autonomic and abundant sensory fibres. Interactions between the autonomic nervous system and immune cells in lymphoid organs are known to contribute to systemic immunity, but how peripheral nerves regulate cutaneous immune responses remains unclear. We exposed the skin of mice to imiquimod, which induces IL-23-dependent psoriasis-like inflammation. Here we show that a subset of sensory neurons expressing the ion channels TRPV1 and Nav1.8 is essential to drive this inflammatory response. Imaging of intact skin revealed that a large fraction of DDCs, the principal source of IL-23, is in close contact with these nociceptors. Upon selective pharmacological or genetic ablation of nociceptors, DDCs failed to produce IL-23 in imiquimod-exposed skin. Consequently, the local production of IL-23-dependent inflammatory cytokines by dermal γδT17 cells and the subsequent recruitment of inflammatory cells to the skin were markedly reduced. Intradermal injection of IL-23 bypassed the requirement for nociceptor communication with DDCs and restored the inflammatory response. These findings indicate that TRPV1(+)Nav1.8(+) nociceptors, by interacting with DDCs, regulate the IL-23/IL-17 pathway and control cutaneous immune responses.
nihms572807.pdf

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