Immunology
Abstract
The functional plasticity of tumor-infiltrating B (TIL-B) cells spans from anti-tumor responses to non-canonical immune suppression. Yet, how tumor microenvironment (TME) influences TIL-B development is still underappreciated. Our current study integrated single cell transcriptomics and BCR (B cell receptor) sequencing to profile TIL-B phenotypes and clonalities in hepatocellular carcinoma (HCC). Using trajectory and gene regulatory network analysis, we were able to characterize plasma cells, memory and naïve B cells within the HCC TME and further revealed a downregulation of BCR-signaling genes in plasma cells and a subset of inflammatory TNF+ memory B cells. Within the TME, non-switch memory B cell subset acquires an age-associated B cell phenotype (TBET+, CD11c+) and expressed higher levels of PD-L1, CD25 and granzyme B. We further demonstrated that the presence of HCC tumor cells could confer suppressive functions on peripheral blood B cells which in turn, dampen T cell co-stimulation. To the best of our knowledge, these findings represent novel mechanisms of non-canonical immune suppression in HCC. While previous studies identified atypical memory B cells in chronic hepatitis and across several solid cancer types, we further highlighted their potential role as regulatory B cells (Bregs) within both the TME and peripheral blood of HCC patients.
Authors
Shi Yong Neo, Timothy Wai Ho Shuen, Shruti Khare, Joni Chong, Maichan Lau, Niranjan Shirgaonkar, Levene Chua, Junzhe Zhao, Keene Lee, Charmaine Tan, Rebecca Ba, Janice Lim, Joelle Chua, Hui Shi Cheong, Hui Min Chai, Chung Yip Chan, Alexander Yaw Fui Chung, Peng Chung Cheow, Prema Raj Jeyaraj, Jin Yao Teo, Ye Xin Koh, Aik Yong Chok, Pierce Kah Hoe Chow, Brian Goh, Wei Keat Wan, Wei Qiang Leow, Tracy Jie Zhen Loh, Po Yin Tang, Jayanthi Karunanithi, Nye Thane Ngo, Tony Kiat Hon Lim, Shengli Xu, Ramanuj Dasgupta, Han Chong Toh, Kong-Peng Lam
Abstract
Chronic lung allograft dysfunction (CLAD) substantially limits long-term survival following lung transplantation. To identify potential targets for CLAD prevention, T cells from explanted CLAD lungs and lung-draining lymph nodes, as well as diseased and nondiseased controls were isolated and single-cell RNA sequencing and TCR sequencing were performed. TCR sequencing revealed a clonally expanded population of CD8+ tissue-resident memory T cells (TRMs) with high cytotoxic potential, including upregulation of KLRK1, encoding the co-receptor NKG2D. These cytotoxic CD8+ TRMs accumulated around the CLAD airways and had a 100-fold increase in clonal overlap with lung-draining lymph nodes when compared with non-CLAD lungs. Using a murine model of orthotopic lung transplantation, we confirmed that cytotoxic CD8+ TRM accumulation was due to chronic rejection and not transplantation alone. Furthermore, blocking NKG2D in vivo attenuated the airway remodeling following transplantation and diminished airway accumulation of CD8+ T cells. Our findings support NKG2D as a potential therapeutic target for CLAD, affecting cytotoxic CD8+ TRM accumulation.
Authors
Kaveh Moghbeli, Madeline A. Lipp, Marta Bueno, Andrew Craig, Michelle Rojas, Minahal Abbas, Zachary I. Lakkis, Byron Chuan, John Sembrat, Kentaro Noda, Daniel J. Kass, Kong Chen, Li Fan, Tim Oury, Zihe Zhou, Xingan Wang, John F. McDyer, Oliver Eickelberg, Mark E. Snyder
Abstract
Necrobiosis is a histologic term used to describe abnormal deposits of “degenerating” collagen within the skin. It can be found as an incidental finding in various granulomatous conditions, but is a hallmark of necrobiosis lipoidica (NL) and necrobiotic xanthogranuloma (NXG). There is limited prior research on necrobiosis. Here, we employed single-cell analysis of lesional and nonlesional skin to study the pathophysiology of necrobiosis. Our findings demonstrate that necrobiotic lesional skin is characterized by SPP1hi macrophages expressing MARCO; NKG7-expressing effector CD8+ T cells coexpressing CCL5, IFNG, GZMs, and PRF1; CCL5hi fibroblasts coexpressing CXCL9, diverse collagens (e.g., COL4A4, COL11A1, COL8A1), and TIMP1; and IGHM-expressing plasma cells. Integrative analysis of signaling ligands and receptor expression identified strong cell-cell communication between NKG7+ T cells, CCL5hi fibroblasts, and SPP1-expressing macrophages. In contrast, these cell populations were not dominant features of systemic sclerosis, another collagen deposition disease. Furthermore, although SPP1-expressing macrophages were detectable in sarcoidosis, IFNG-expressing T cells were a more defining feature of sarcoidosis compared with NL and NXG. From these findings, we speculate that necrobiosis results from the deposition of diverse collagens and ECM proteins through a process driven by CCL5-expressing fibroblasts and SPP1-expressing macrophages.
Authors
Stephanie T. Le, Alina I. Marusina, Alexander A. Merleev, Amanda Kirane, Olga Kruglinskaya, Andrey Kunitsyn, Nikolay Yu Kuzminykh, Xianying Xing, Sophie Y. Li, William Liakos, J. Michelle Kahlenberg, Andrea Gompers, Lauren Downing, Sahiti Marella, Allison C. Billi, Paul W. Harms, Lam C. Tsoi, Marie-Charlotte Brüggen, Iannis E. Adamopoulos, Johann E. Gudjonsson, Emanual Maverakis
Abstract
Dengue is widespread in tropical and subtropical regions globally and imposes a considerable disease burden. Annually, dengue virus (DENV) causes up to 400 million infections, of which approximately 25% present with clinical manifestations ranging from mild to fatal. Despite its significance as a growing public health concern, developing effective DENV vaccines has been challenging. One reason is the lack of comprehensive understanding of the influence exerted by prior DENV infections and immune responses with cross-reactive properties. To investigate this, we collected samples from a pediatric cohort study in dengue-endemic Managua, Nicaragua. We characterized T cell responses in 71 healthy children who had previously experienced 1 or more natural DENV infections and who, within 1 year after sample collection, had a subsequent DENV infection that was either symptomatic or inapparent. Our study investigated the effect of preexisting DENV-specific T cell responses on clinical outcomes of subsequent DENV infection. We assessed DENV-specific T cell responses using an activation-induced marker assay. Children with only 1 prior DENV infection displayed heterogeneous DENV-specific CD4+ and CD8+ T cell frequencies. In contrast, children with 2 or more prior DENV infections showed significantly higher DENV-specific CD4+ and CD8+ T cell frequencies associated with inapparent rather than symptomatic outcomes in subsequent infection. These findings demonstrate the protective role of DENV-specific T cells against symptomatic DENV infection and advance efforts to identify protective immune correlates against dengue.
Authors
Rosa Isela Gálvez, Amparo Martínez-Pérez, E. Alexandar Escarrega, Tulika Singh, José Victor Zambrana, Ángel Balmaseda, Eva Harris, Daniela Weiskopf
Abstract
Access to the brain for treating neurological sequalae requires a craniotomy, which can be complicated by infection. Staphylococcus aureus accounts for half of craniotomy infections, increasing morbidity in a medically fragile patient population. T cells preferentially traffic to the brain during craniotomy infection; however, their functional importance is unknown. Using a mouse model of S. aureus craniotomy infection, CD4+ T cells were critical for bacterial containment, as treatment of WT animals with anti-CD4 exacerbated infection that was similar to phenotypes in Rag1–/– mice. Single-cell RNA-Seq (scRNA-Seq) revealed transcriptional heterogeneity in brain CD3+ infiltrates, with CD4+ cells most prominent that displayed Th1- and Th17-like characteristics, and adoptive transfer of either subset in Rag1–/– animals during early infection prevented S. aureus outgrowth. scRNA-Seq identified a robust IFN signature in several innate immune clusters, and examination of cell-to-cell interactions revealed extensive T cell crosstalk with monocytes/macrophages that was also observed in human craniotomy infection. A cooperative role for Th1 and Th17 responses was demonstrated by treatment of Ifng–/– mice with IL-17A neutralizing antibody that recapitulated phenotypes in Rag1–/– animals. Collectively, these findings implicate Th1- and Th17-mediated proinflammatory responses in shaping the innate immune landscape for S. aureus containment during craniotomy infection.
Authors
Gunjan Kak, Zachary Van Roy, Rachel W. Fallet, Lee E. Korshoj, Tammy Kielian
Abstract
Idiopathic pulmonary fibrosis (IPF) is characterized by progressive scarring and loss of lung function. With limited treatment options, patients succumb to the disease within 2 to 5 years. The molecular pathogenesis of IPF regarding the immunologic changes that occur is poorly understood. We characterize a role for non-canonical aryl-hydrocarbon receptor signaling (ncAHR) in dendritic cells (DCs) that leads to production of IL-6 and increased IL-17+ cells, promoting fibrosis. TLR9 signaling in myofibroblasts is shown to regulate production of TDO2 which converts tryptophan into the endogenous AHR ligand kynurenine. Mice with augmented ncAHR signaling were created by crossing floxed AHR exon-2 deletion mice (AHRΔex2) with mice harboring a CD11c-Cre. Bleomycin (blm) was used to study fibrotic pathogenesis. Isolated CD11c+ cells and primary fibroblasts were treated ex-vivo with relevant TLR agonists and AHR modulating compounds to study how AHR signaling influenced inflammatory cytokine production. Human datasets were also interrogated. Inhibition of all AHR signaling rescued fibrosis, however, AHRΔex2 mice treated with blm developed more fibrosis and DCs from these mice were hyperinflammatory and profibrotic upon adoptive transfer. Treatment of fibrotic fibroblasts with TLR9 agonist increased expression of TDO2 and fibrotic fibroblasts activated IL-6 production in CD103+ DCs. Study of human samples corroborates the relevance of these findings in IPF patients. We also, for the first time, identify that AHR exon-2 floxed mice retain capacity for ncAHR signaling.
Authors
Hannah Carter, Rita Medina Costa, Taylor S. Adams, Talon M. Gilchrist, Claire E. Emch, Monica Bame, Justin M. Oldham, Steven K. Huang, Angela L. Linderholm, Imre Noth, Naftali Kaminski, Bethany B. Moore, Stephen J. Gurczynski
Abstract
Colorectal pre-cancers in Lynch Syndrome (LS) exhibit a distinct immune profile, presenting unique opportunities for developing immune-interception strategies to prevent carcinogenesis. Epigenetic modulation by EZH2 of immune-related genes is implicated in the carcinogenesis of different cancer types including colorectal. This study utilizes a mouse model of LS and ex vivo colonic organoids to assess the effects of the EZH2 inhibitor GSK503 on immune regulatory pathways, tumorigenesis, and epigenetic reprogramming. Our findings revealed that GSK503 significantly increased CD4+ and CD8+ T cells in both splenocytes and colonic mucosa of treated mice compared to controls. Additionally, a preventive dose of GSK503 over 9 weeks notably reduced adenoma multiplicity, demonstrating its efficacy as a preventive modality. Single-cell RNA sequencing and molecular analyses showed activation of immune and apoptotic markers, along with a reduction in H3K27 methylation levels in colonic crypts. ChIP sequencing further revealed decreased levels of H3K27me3 and H3K4me1, while levels of the active enhancer marks H3K4me3 and H3K27Ac increased in treated mice. Collectively, these findings indicate that EZH2 inhibition enhances immune responses through epigenetic reprogramming in the genome of LS mice, establishing a promising framework for the clinical development of EZH2 inhibitors as a cancer prevention strategy for LS carriers.
Authors
Charles M. Bowen, Fahriye Duzagac, Abel Martel-Martel, Laura Reyes-Uribe, Mahira Zaheer, Jacklyn Thompson, Nan Deng, Ria Sinha, Soham Mazumdar, Melissa W. Taggart, Abhinav K. Jain, Winfried Edelmann, Krishna M. Sinha, Eduardo Vilar
Abstract
Endothelial injury destroys endothelial barrier integrity, triggering organ dysfunction and ultimately resulting in sepsis-related death. Considerable attention has been focused on identifying effective targets for inhibiting damage to endothelial cells to treat endotoxemia-induced septic shock. Global gasdermin D (Gsdmd) deletion reportedly prevents death caused by endotoxemia. However, the role of endothelial GSDMD in endothelial injury and lethality in lipopolysaccharide-induced (LPS-induced) endotoxemia and the underlying regulatory mechanisms are unknown. Here, we show that LPS increases endothelial GSDMD level in aortas and lung microvessels. We demonstrated that endothelial Gsdmd deficiency, but not myeloid cell Gsdmd deletion, protects against endothelial injury and death in mice with endotoxemia or sepsis. In vivo experiments suggested that hepatocyte GSDMD mediated the release of high-mobility group box 1, which subsequently binds to the receptor for advanced glycation end products in endothelial cells to cause systemic vascular injury, ultimately resulting in acute lung injury and lethality in shock driven by endotoxemia or sepsis. Additionally, inhibiting endothelial GSDMD activation via a polypeptide inhibitor alleviated endothelial damage and improved survival in a mouse model of endotoxemia or sepsis. These data suggest that endothelial GSDMD is a viable pharmaceutical target for treating endotoxemia and endotoxemia-induced sepsis.
Authors
Enyong Su, Xiaoyue Song, Lili Wei, Junqiang Xue, Xuelin Cheng, Shiyao Xie, Hong Jiang, Ming Liu
Abstract
Induction of podoplanin (PDPN) expression is a critical response of macrophages to LPS stimulation or bacterial infection in sepsis, but how this key process of TLR4-stimulated PDPN upregulation is regulated and the impact of PDPN expression on macrophage function remain elusive. Here, we determined how this process is regulated in vitro and in vivo. PDPN failed to be upregulated in TLR4 stimulated macrophages deficient in adhesion and degranulation-promoting adapter protein (ADAP), which could be rescued by the reconstitution of ADAP. A distinct PDPNhi peritoneal macrophage (PM) subset, which exhibited an M2-like phenotype and enhanced phagocytic activity, was generated in WT but not in ADAP-deficient septic mice. The blockade of PDPNhi PMs mimicked the effect of ADAP deficiency, which exacerbated sepsis. Mechanistically, BTK-mediated ADAP Y571 phosphorylation worked together with mTOR to converge on STAT3 activation for the transactivation of the PDPN promoter. Moreover, agonist activation of STAT3 profoundly potentiated the PDPNhi PM subset generation and alleviated sepsis severity in mice. Together, our findings reveal a mechanism whereby ADAP resets macrophage function by controlling the TLR4-induced upregulation of PDPN as a host innate immune defense during sepsis.
Authors
Pengchao Zhang, Xinning Wang, Xiaodong Yang, Hebin Liu
Abstract
Despite combination antiretroviral therapy (ART), HIV causes persistent gut barrier dysfunction, immune depletion, and dysbiosis. Further, ART interruption results in reservoir reactivation and rebound viremia. Both IL-21 and anti-α4β7 improve gut barrier functions, and we hypothesized combining them would synergize as a dual therapy to improve immunological outcomes in SIV-infected rhesus macaques (RMs). We found no significant differences in CD4+ T-cell reservoir size by intact proviral DNA assay. SIV rebounded in both dual-treated and control RMs following analytical therapy interruption (ATI), with time to rebound and initial rebound viremia comparable between groups; however, dual-treated RMs showed slightly better control of viral replication at the latest time points post-ATI. Additionally, following post-ATI, dual-treated RMs showed immunological benefits, including T-cell preservation and lower PD-1+ central memory T-cell (TCM) frequency. Notably, PD-1+ TCMs were associated with reservoir size, which predicted viral loads (VLs) post-ATI. Finally, 16S rRNA sequencing revealed better recovery from dysbiosis in treated animals, and the butyrate-producing Firmicute Roseburia predicted PD-1-expressing TCMs and VLs after ATI. PD-1+ TCMs and gut dysbiosis represent mechanisms of HIV persistence and pathogenesis, respectively. Therefore, combining IL-21 and anti-α4β7 may be an effective therapeutic strategy to improve immunological outcomes for people with HIV.
Authors
Samuel D. Johnson, Maria Pino, Arpan Acharya, Julien A. Clain, Deepanwita Bose, Kevin Nguyen, Justin Harper, Francois Villinger, Mirko Paiardini, Siddappa N. Byrareddy
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