Person: Anandasabapathy, Niroshana
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Anandasabapathy
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Niroshana
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Anandasabapathy, Niroshana
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Publication Type I interferons and microbial metabolites of tryptophan modulate astrocyte activity and CNS inflammation via the aryl hydrocarbon receptor(2016) Rothhammer, Veit; Mascanfroni, Ivan D.; Bunse, Lukas; Takenaka, Maisa C.; Kenison, Jessica E.; Mayo, Lior; Chao, Chun-Cheih; Patel, Bonny; Yan, Raymond; Blain, Manon; Alvarez, Jorge I.; Kébir, Hania; Anandasabapathy, Niroshana; Izquierdo, Guillermo; Jung, Steffen; Obholzer, Nikolaus; Pochet, Nathalie; Clish, Clary B.; Prinz, Marco; Prat, Alexandre; Antel, Jack; Quintana, FranciscoAstrocytes play important roles in the central nervous system (CNS) during health and disease. Through genome-wide analyses we detected a transcriptional response to type I interferons (IFN-I) in astrocytes during experimental CNS autoimmunity and also in CNS lesions from multiple sclerosis (MS) patients. IFN-I signaling in astrocytes reduces inflammation and experimental autoimmune encephalomyelitis (EAE) disease scores via the ligand-activated transcription factor aryl hydrocarbon receptor (AhR) and suppressor of cytokine signaling 2 (SOCS2). The anti-inflammatory effects of nasally administered IFN-β are partly mediated by AhR. Dietary tryptophan is metabolized by the gut microbiota into AhR agonists that act on astrocytes to limit CNS inflammation. EAE scores were increased following ampicillin treatment during the recovery phase, and CNS inflammation was reduced in antibiotic-treated mice by supplementation with the tryptophan metabolites indole, indoxyl-3-sulfate (I3S), indole-3-propionic acid (IPA) and indole-3-aldehyde (IAld), or the bacterial enzyme tryptophanase. In individuals with MS, the circulating levels of AhR agonists were decreased. These findings suggest that IFN-I produced in the CNS act in combination with metabolites derived from dietary tryptophan by the gut flora to activate AhR signaling in astrocytes and suppress CNS inflammation.Publication Flt3L-dependence helps define an uncharacterized subset of murine cutaneous dendritic cells(2014) Mollah, Shamim; Dobrin, Joseph; Feder, Rachel; Tse, Sze-Wah; Matos, Ines; Cheong, Cheolho; Steinman, Ralph M.; Anandasabapathy, NiroshanaSkin-derived dendritic cells (DC) are potent antigen presenting cells with critical roles in both adaptive immunity and tolerance to self. Skin DC carry antigens and constitutively migrate to the skin draining lymph nodes (LN). In mice, Langerin-CD11b− dermal DC are a low-frequency, heterogeneous, migratory DC subset that traffic to LN (Langerin-CD11b-migDC). Here, we build on the observation that Langerin-CD11b− migDC are Fms-like tyrosine kinase 3 ligand (Flt3L) dependent and strongly Flt3L responsive, which may relate them to classical DCs. Examination of DC capture of FITC from painted skin, DC isolation from skin explant culture, and from the skin of CCR7 knockout mice which accumulate migDC, demonstrate these cells are cutaneous residents. Langerin-CD11b-Flt3L responsive DC are largely CD24(+) and CX3CR1low and can be depleted from Zbtb46-DTR mice, suggesting classical DC lineage. Langerin-CD11bmigDC present antigen with equal efficiency to other DC subsets ex vivo including classical CD8α cDC and Langerin+CD103+ dermal DC. Finally, transcriptome analysis suggests a close relationship to other skin DC, and a lineage relationship to other classical DC. This work demonstrates that Langerin- CD11b− dermal DC, a previously overlooked cell subset, may be an important player in the cutaneous immune environment.Publication Classical Flt3L-dependent dendritic cells control immunity to protein vaccine(The Rockefeller University Press, 2014) Anandasabapathy, Niroshana; Feder, Rachel; Mollah, Shamim; Tse, Sze-Wah; Longhi, Maria Paula; Mehandru, Saurabh; Matos, Ines; Cheong, Cheolho; Ruane, Darren; Brane, Lucas; Teixeira, Angela; Dobrin, Joseph; Mizenina, Olga; Park, Chae Gyu; Meredith, Matthew; Clausen, Björn E.; Nussenzweig, Michel C.; Steinman, Ralph M.DCs are critical for initiating immunity. The current paradigm in vaccine biology is that DCs migrating from peripheral tissue and classical lymphoid-resident DCs (cDCs) cooperate in the draining LNs to initiate priming and proliferation of T cells. Here, we observe subcutaneous immunity is Fms-like tyrosine kinase 3 ligand (Flt3L) dependent. Flt3L is rapidly secreted after immunization; Flt3 deletion reduces T cell responses by 50%. Flt3L enhances global T cell and humoral immunity as well as both the numbers and antigen capture capacity of migratory DCs (migDCs) and LN-resident cDCs. Surprisingly, however, we find immunity is controlled by cDCs and actively tempered in vivo by migDCs. Deletion of Langerin+ DC or blockade of DC migration improves immunity. Consistent with an immune-regulatory role, transcriptomic analyses reveals different skin migDC subsets in both mouse and human cluster together, and share immune-suppressing gene expression and regulatory pathways. These data reveal that protective immunity to protein vaccines is controlled by Flt3L-dependent, LN-resident cDCs.Publication Id1 suppresses anti-tumour immune responses and promotes tumour progression by impairing myeloid cell maturation(Nature Pub. Group, 2015) Papaspyridonos, Marianna; Matei, Irina; Huang, Yujie; do Rosario Andre, Maria; Brazier-Mitouart, Helene; Waite, Janelle C.; Chan, April S.; Kalter, Julie; Ramos, Ilyssa; Wu, Qi; Williams, Caitlin; Wolchok, Jedd D.; Chapman, Paul B.; Peinado, Hector; Anandasabapathy, Niroshana; Ocean, Allyson J.; Kaplan, Rosandra N.; Greenfield, Jeffrey P.; Bromberg, Jacqueline; Skokos, Dimitris; Lyden, DavidA central mechanism of tumour progression and metastasis involves the generation of an immunosuppressive ‘macroenvironment' mediated in part through tumour-secreted factors. Here we demonstrate that upregulation of the Inhibitor of Differentiation 1 (Id1), in response to tumour-derived factors, such as TGFβ, is responsible for the switch from dendritic cell (DC) differentiation to myeloid-derived suppressor cell expansion during tumour progression. Genetic inactivation of Id1 largely corrects the myeloid imbalance, whereas Id1 overexpression in the absence of tumour-derived factors re-creates it. Id1 overexpression leads to systemic immunosuppression by downregulation of key molecules involved in DC differentiation and suppression of CD8 T-cell proliferation, thus promoting primary tumour growth and metastatic progression. Furthermore, advanced melanoma patients have increased plasma TGFβ levels and express higher levels of ID1 in myeloid peripheral blood cells. This study reveals a critical role for Id1 in suppressing the anti-tumour immune response during tumour progression and metastasis.Publication Core skin DC signatures control immune tolerance to skin cancer and limit anti-tumor immunity(BioMed Central, 2015) Nirschl, Christopher; Liu, Yong; Sarin, Kavita; Suarez-Farinas, Mayte; Chau, David; Sage, Peter; Sharpe, Arlene; Anandasabapathy, Niroshana