Immunology
Abstract
Identifying host factors that contribute to pneumonia incidence and severity are of utmost importance to guiding the development of more effective therapies. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a scavenger receptor known to promote vascular injury and inflammation, but it is unknown whether and how LOX-1 functions in the lung. Here, we provide evidence of substantial accumulation of LOX-1 in the lungs of ARDS patients and in mice with pneumonia. Unlike previously described injurious contributions of LOX-1, we found that LOX-1 is uniquely protective in the pulmonary airspaces, limiting proteinaceous edema and inflammation. We also identified alveolar macrophages and recruited neutrophils as two prominent sites of LOX-1 expression in the lungs, whereby macrophages are capable of further induction during pneumonia and neutrophils exhibit a rapid, but heterogenous elevation of LOX-1 in the infected lung. Blockade of LOX-1 led to dysregulated immune signaling in alveolar macrophages, marked by alterations in activation markers and a concomitant elevation of inflammatory gene networks. However, bone marrow chimeras also suggested a prominent role for neutrophils in LOX-1-mediated lung protection, further supported by LOX-1+ neutrophils exhibiting transcriptional changes consistent with reparative processes. Taken together, this work establishes LOX-1 as a tissue-protective factor in the lungs during pneumonia, possibly mediated by its influence on immune signaling in alveolar macrophages (AMs) and LOX-1+ airspace neutrophils.
Authors
Filiz T. Korkmaz, Anukul T. Shenoy, Elise Symer, Lillia A. Baird, Christine V. Odom, Emad Arafa, Ernest L. Dimbo, Elim Na, William Molina-Arocho, Matthew Brudner, Theodore J. Standiford, Jawahar L. Mehta, Tatsuya Sawamura, Matthew R. Jones, Joseph P. Mizgerd, Katrina T. Traber, Lee J. Quinton
Abstract
BRD4 is a bromodomain extra-terminal domain (BET) family member and functions primarily as a chromatin reader regulating genes involved in cell fate decisions. Here we bred Brd4f/fOx40-Cre mice in which Brd4 was conditionally deleted in OX40-expressing cells to examine the role of BRD4 in regulating immune responses. We found that the Brd4f/fOx40-Cre mice developed profound alopecia and dermatitis while other organs and tissues were not affected. Surprisingly, lineage-tracing experiments using the Rosa26f/f-Yfp mice identified a subset of hair follicle stem cells (HFSCs) that constitutively express OX40 and deletion of Brd4 specifically in such HFSCs resulted in cell death and a complete loss of skin hair growth. We also found that death of HFSCs triggered massive activation of the intra-dermal γδ T cells, which induced epidermal hyperplasia and dermatitis by producing the inflammatory cytokine IL-17. Interestingly, deletion of Brd4 in Foxp3+ Tregs, which also constitutively express OX40, compromised their suppressive functions and this in turn contributed to the enhanced activation of γδ T cells as well as the severity of dermatitis and hair follicle destruction. Thus, our data demonstrate an unexpected role of BRD4 in regulating skin follicle stem cells and skin inflammation.
Authors
Mou Wen, Yuanlin Ying, Xiang Xiao, Preston R. Arnold, Guangchuan Wang, Xiufeng Chu, Rafik M. Ghobrial, Xian C. Li
Abstract
TP53 mutation (TP53mut) is one of the most important driver events facilitating tumorigenesis, which could induce a series of chain reactions to promote tumor malignant transformation. However, the malignancy progression patterns under TP53 mutation still remain less known. Clarifying the molecular landscapes of TP53mut tumors will help us understand the process of tumor development and aid precise treatment. Here, we distilled genetic and epigenetic features altered in TP53mut cancers for cluster-of-cluster analysis. Using integrated classification, we derived five different subtypes of TP53mut patients. These subtypes have distinct features in genomic alteration, clinical relevance, microenvironment dysregulation and potential therapeutics. Among the five subtypes, COCA3 was identified as the subtype with worst prognosis, causing an immunosuppressive microenvironment and immunotherapeutic resistantance. Further drug efficacy research highlighted olaparib as the most promising therapeutic agents for COCA3 tumors. Importantly, the therapeutic efficacy of olaparib in COCA3 and immunotherapy in non-COCA3 tumors was validated in vivo experiment. Summarily, our study first explored the important molecular events and developed a subtype classification system with distinct targeted therapy strategies for different subtypes of TP53mut tumors. These multi-omics classification systems provided a valuable resource that significantly expands the knowledge of TP53mut tumors and might eventually benefit in clinical practice.
Authors
Xin Chen, Tianqi Liu, Wu Jianqi, Chen Zhu, Gefei Guan, Cunyi Zou, Qing Guo, Xiaolin Ren, Chen Li, Peng Cheng, Wen Cheng, Anhua Wu
Abstract
Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized. By generating mouse strains deficient in cell-specific exosome production, we demonstrate deletion of the small GTPase Rab27A in CD11c+ cells exacerbated murine colitis, which was reversible through administration of DC-derived exosomes. Profiling RNAs within colon exosomes revealed a distinct subset of miRNAs carried by colon- and DC-derived exosomes. Among antiinflammatory exosomal miRNAs, miR-146a was transferred from gut immune cells to myeloid and T cells through a Rab27-dependent mechanism, targeting Traf6, IRAK-1, and NLRP3 in macrophages. Further, we have identified a potentially novel mode of exosome-mediated DC and macrophage crosstalk that is capable of skewing gut macrophages toward an antiinflammatory phenotype. Assessing clinical samples, RAB27A, select miRNAs, and RNA-binding proteins that load exosomal miRNAs were dysregulated in ulcerative colitis patient samples, consistent with our preclinical mouse model findings. Together, our work reveals an exosome-mediated regulatory mechanism underlying gut inflammation and paves the way for potential use of miRNA-containing exosomes as a novel therapeutic for inflammatory bowel disease.
Authors
Kaylyn M. Bauer, Morgan C. Nelson, William W. Tang, Tyson R. Chiaro, D. Garrett Brown, Arevik Ghazaryan, Soh-Hyun Lee, Allison M. Weis, Jennifer H. Hill, Kendra A. Klag, Van B. Tran, Jacob W. Thompson, Andrew G. Ramstead, Josh K. Monts, James E. Marvin, Margaret Alexander, Warren P. Voth, W. Zac Stephens, Diane M. Ward, Aaron C. Petrey, June L. Round, Ryan M. O’Connell
Abstract
Mass cytometry, or cytometry by TOF (CyTOF), provides a robust means of determining protein-level measurements of more than 40 markers simultaneously. While the functional states of immune cells occur along continuous phenotypic transitions, cytometric studies surveying cell phenotypes often rely on static metrics, such as discrete cell-type abundances, based on canonical markers and/or restrictive gating strategies. To overcome this limitation, we applied single-cell trajectory inference and nonnegative matrix factorization methods to CyTOF data to trace the dynamics of T cell states. In the setting of cancer immunotherapy, we showed that patient-specific summaries of continuous phenotypic shifts in T cells could be inferred from peripheral blood–derived CyTOF mass cytometry data. We further illustrated that transfer learning enabled these T cell continuous metrics to be used to estimate patient-specific cell states in new sample cohorts from a reference patient data set. Our work establishes the utility of continuous metrics for CyTOF analysis as tools for translational discovery.
Authors
Dimitrios N. Sidiropoulos, Genevieve L. Stein-O’Brien, Ludmila Danilova, Nicole E. Gross, Soren Charmsaz, Stephanie Xavier, James Leatherman, Hao Wang, Mark Yarchoan, Elizabeth M. Jaffee, Elana J. Fertig, Won Jin Ho
Abstract
Expression of the transcription factor Interferon Regulatory Factor 4 (IRF4) is required for the development of lung conventional dendritic cells type 2 (cDC2s) that elicit Th2 responses, yet how IRF4 functions in lung cDC2s throughout the acute and memory allergic response is not clear. Here, we use a novel mouse model that loses IRF4 expression after lung cDC2 development to demonstrate that mice with IRF4-deficient DCs display impaired memory responses to allergen. This defect in the memory response is a direct result of ineffective Th2 induction and impaired recruitment of activated effector T cells to the lung after sensitization. IRF4-deficient DCs demonstrate defects in their migration to the draining lymph node and in T cell priming. Finally, T cells primed by IRF4-competent DCs mediate potent memory responses independently of IRF4-expressing DCs, demonstrating that IRF4-expressing DCs are not necessary during the memory response. Thus, IRF4 controls a program in mature DCs governing Th2 priming and effector responses, but IRF4-expressing DCs are dispensable during tissue resident-memory T cell (TRM cell)-dependent memory responses.
Authors
Daniel F. Camacho, Tania E. Velez, Maile K. Hollinger, Esther Wang, Chanie L. Howard, Eli P. Darnell, Domenick E. Kennedy, Paulette A. Krishack, Cara L. Hrusch, Marcus R. Clark, James J. Moon, Anne I. Sperling
Abstract
Immune-related adverse events are a major hurdle to the success of immunotherapy. The immunological mechanisms underlying their development and relation to anti-tumour responses are poorly understood. By examining both systemic and tissue-specific immune changes induced by combination anti-CTLA-4 and anti-PD-1 immunotherapy, we found distinct repertoire changes in patients who developed moderate-severe colitis irrespective of their anti-tumour response to therapy. The proportion of circulating monocytes were significantly increased at baseline in patients who subsequently developed colitis compared to patients who did not develop colitis and biopsies from patients with colitis showed monocytic infiltration of both endoscopically and histopathologically normal and inflamed regions of colon. The magnitude of systemic expansion of T cells following commencement of immunotherapy was also greater in patients who developed colitis. Importantly, we show expansion of specific T cell subsets within inflamed regions of the colon, including tissue-resident memory CD8+ T cells and Th1 CD4+ T cells in patients who developed colitis. Our data also suggest that CD8+ T cell expansion was locally induced, while Th1 cell expansion was systemic. Together our data show exaggerated innate and T cell responses to combination immunotherapy synergise to propel colitis in susceptible patients.
Authors
Kazi J. Nahar, Felix Marsh-Wakefield, Robert V. Rawson, Tuba N. Gide, Angela L. Ferguson, Ruth O. Allen, Camelia Quek, Ines Pires da Silva, Stephen Tattersall, Christopher J. Kiely, Neomal Sandanayake, Matteo S. Carlino, Geoff McCaughan, James S. Wilmott, Richard A. Scolyer, Georgina V. Long, Alexander M. Menzies, Umaimainthan Palendira
Abstract
A side effect of antibiotics is outgrowth of the opportunistic fungus Candida albicans in the oropharynx (oropharyngeal candidiasis, OPC). IL-17 signaling is vital for immunity to OPC, but how the microbiome impacts antifungal immunity is not well understood. Mice in standard specific pathogen–free (SPF) conditions are resistant to OPC, whereas we show that germ-free (GF) or antibiotic-treated mice are susceptible. Oral type 17 cells and IL-17–dependent responses were impaired in antibiotic-treated and GF mice. Susceptibility could be rescued in GF mice by mono-colonization with segmented filamentous bacterium (SFB), an intestine-specific constituent of the microbiota. SFB protection was accompanied by restoration of oral IL-17+CD4+ T cells and gene signatures characteristic of IL-17 signaling. Additionally, RNA-Seq revealed induction of genes in the retinoic acid (RA) and RA receptor–α (RARα) pathway. Administration of RA rescued immunity to OPC in microbiome-depleted or GF mice, while RAR inhibition caused susceptibility in immunocompetent animals. Surprisingly, immunity to OPC was independent of serum amyloids. Moreover, RAR inhibition did not alter oral type 17 cytokine levels. Thus, mono-colonization with a component of the intestinal microflora confers protection against OPC by type 17 and RA/RARα, which act in parallel to promote antifungal immunity. In principle, manipulation of the microbiome could be harnessed to maintain antifungal immunity.
Authors
Felix E.Y. Aggor, Martinna Bertolini, Chunsheng Zhou, Tiffany C. Taylor, Darryl A. Abbott, Javonn Musgrove, Vincent M. Bruno, Timothy W. Hand, Sarah L. Gaffen
Abstract
Cross-reactive immunity between SARS-CoV-2 and other related coronaviruses has been well-documented, and it may play a role in preventing severe COVID-19. Epidemiological studies early in the pandemic showed a geographical association between high influenza vaccination rates and lower incidence of SARS-CoV-2 infection. We, therefore, analyzed whether exposure to influenza A virus (IAV) antigens could influence the T cell repertoire in response to SARS-CoV-2, indicating a heterologous immune response between these 2 unrelated viruses. Using artificial antigen-presenting cells (aAPCs) combined with real-time reverse-transcription PCR (RT-qPCR), we developed a sensitive assay to quickly screen for antigen-specific T cell responses and detected a significant correlation between responses to SARS-CoV-2 epitopes and IAV dominant epitope (M158–66). Further analysis showed that some COVID-19 convalescent donors exhibited both T cell receptor (TCR) specificity and functional cytokine responses to multiple SARS-CoV-2 epitopes and M158–66. Utilizing an aAPC-based stimulation/expansion assay, we detected cross-reactive T cells with specificity to SARS-CoV-2 and IAV. In addition, TCR sequencing of the cross-reactive and IAV-specific T cells revealed similarities between the TCR repertoires of the two populations. These results indicate that heterologous immunity shaped by our exposure to other unrelated endemic viruses may affect our immune response to novel viruses such as SARS-CoV-2.
Authors
Worarat Chaisawangwong, Hanzhi Wang, Theodore Kouo, Sebastian F. Salathe, Ariel Isser, Joan Glick Bieler, Maya L. Zhang, Natalie K. Livingston, Shuyi Li, Joseph J. Horowitz, Ron E. Samet, Israel Zyskind, Avi Z. Rosenberg, Jonathan P. Schneck
Abstract
Although Barrett’s metaplasia of the esophagus (BE) is the only known precursor lesion to esophageal adenocarcinomas (EACs), drivers of cellular transformation in BE remain incompletely understood. We use an artificial intelligence–guided network approach to study EAC initiation and progression. Key predictions are subsequently validated in a human organoid model, in patient-derived biopsy specimens of BE, a case-control study of genomics of BE progression, and in a cross-sectional study of 113 patients with BE and EACs. Our model classified healthy esophagus from BE and BE from EACs in several publicly available gene expression data sets (n = 932 samples). The model confirmed that all EACs must originate from BE and pinpointed a CXCL8/IL8↔neutrophil immune microenvironment as a driver of cellular transformation in EACs and gastroesophageal junction adenocarcinomas. This driver is prominent in White individuals but is notably absent in African Americans (AAs). Network-derived gene signatures, independent signatures of neutrophil processes, CXCL8/IL8 expression, and an absolute neutrophil count (ANC) are associated with risk of progression. SNPs associated with changes in ANC by ethnicity (e.g., benign ethnic neutropenia [BEN]) modify that risk. Findings define a racially influenced immunological basis for cell transformation and suggest that BEN in AAs may be a deterrent to BE→EAC progression.
Authors
Pradipta Ghosh, Vinicius J. Campos, Daniella T. Vo, Caitlin Guccione, Vanae Goheen-Holland, Courtney Tindle, Guilherme S. Mazzini, Yudou He, Ludmil B. Alexandrov, Scott M. Lippman, Richard R. Gurski, Soumita Das, Rena Yadlapati, Kit Curtius, Debashis Sahoo
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