Publications by authors named "Eric T Clambey"

49 Publications

Cancer Cell-Specific Major Histocompatibility Complex II Expression as a Determinant of the Immune Infiltrate Organization and Function in the NSCLC Tumor Microenvironment.

J Thorac Oncol 2021 May 25. Epub 2021 May 25.

Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado. Electronic address:

Introduction: In patients with NSCLC, the prognostic significance of the tumor microenvironment (TME) immune composition has been revealed using single- or dual-marker staining on sequential tissue sections. Although these studies reveal that relative abundance and localization of immune cells are important parameters, deeper analyses of the NSCLC TME are necessary to refine the potential application of these findings to clinical care. Currently, the complex spatial relationships between cells of the NSCLC TME and potential drivers contributing to its immunologic composition remain unknown.

Methods: We used multispectral quantitative imaging on the lung adenocarcinoma TME in 153 patients with resected tumors. On a single slide per patient, we evaluated the TME with markers for CD3, CD8, CD14, CD19, major histocompatibility complex II (MHCII), cytokeratin, and 4',6-diamidino-2-phenylindole (DAPI). Image analysis, including tissue segmentation, phenotyping, and spatial localization, was performed.

Results: Specimens wherein greater than or equal to 5% of lung cancer cells expressed MHCII (MHCII TME) had increased levels of CD4 and CD8 T cells and CD14 cell infiltration. In the MHCII TME, the immune infiltrate was closer to cancer cells and expressed an activated phenotype. Morphologic image analysis revealed cancer cells in the MHCII TME more frequently interfaced with CD4 and CD8 T cells. Patients with an MHCII TME experienced improved overall survival (p = 0.046).

Conclusions: Lung cancer cell-specific expression of MHCII associates with levels of immune cell infiltration, spatial localization, and activation status within the TME. This suggests that cancer cell-specific expression of MHCII may represent a biomarker for the immune system's recognition and activation against the tumor.
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http://dx.doi.org/10.1016/j.jtho.2021.05.004DOI Listing
May 2021

Lytic Infection with Murine Gammaherpesvirus 68 Activates Host and Viral RNA Polymerase III Promoters and Enhances Noncoding RNA Expression.

J Virol 2021 Jun 24;95(14):e0007921. Epub 2021 Jun 24.

Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.

RNA polymerase III (pol III) transcribes multiple noncoding RNAs (ncRNAs) that are essential for cellular function. Pol III-dependent transcription is also engaged during certain viral infections, including those of the gammaherpesviruses (γHVs), where pol III-dependent viral ncRNAs promote pathogenesis. Additionally, several host ncRNAs are upregulated during γHV infection and play integral roles in pathogenesis by facilitating viral establishment and gene expression. Here, we sought to investigate how pol III promoters and transcripts are regulated during gammaherpesvirus infection using the murine gammaherpesvirus 68 (γHV68) system. To compare the transcription of host and viral pol III-dependent ncRNAs, we analyzed a series of pol III promoters for host and viral ncRNAs using a luciferase reporter optimized to measure pol III activity. We measured promoter activity from the reporter gene at the translation level via luciferase activity and at the transcription level via reverse transcription-quantitative PCR (RT-qPCR). We further measured endogenous ncRNA expression at single-cell resolution by flow cytometry. These studies demonstrated that lytic infection with γHV68 increased the transcription from multiple host and viral pol III promoters and further identified the ability of accessory sequences to influence both baseline and inducible promoter activity after infection. RNA flow cytometry revealed the induction of endogenous pol III-derived ncRNAs that tightly correlated with viral gene expression. These studies highlight how lytic gammaherpesvirus infection alters the transcriptional landscape of host cells to increase pol III-derived RNAs, a process that may further modify cellular function and enhance viral gene expression and pathogenesis. Gammaherpesviruses are a prime example of how viruses can alter the host transcriptional landscape to establish infection. Despite major insights into how these viruses modify RNA polymerase II-dependent generation of messenger RNAs, how these viruses influence the activity of host RNA polymerase III remains much less clear. Small noncoding RNAs produced by RNA polymerase III are increasingly recognized to play critical regulatory roles in cell biology and virus infection. Studies of RNA polymerase III-dependent transcription are complicated by multiple promoter types and diverse RNAs with variable stability and processing requirements. Here, we characterized a reporter system to directly study RNA polymerase III-dependent responses during gammaherpesvirus infection and utilized single-cell flow cytometry-based methods to reveal that gammaherpesvirus lytic replication broadly induces pol III activity to enhance host and viral noncoding RNA expression within the infected cell.
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http://dx.doi.org/10.1128/JVI.00079-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223928PMC
June 2021

Targeting resistance to radiation-immunotherapy in cold HNSCCs by modulating the Treg-dendritic cell axis.

J Immunother Cancer 2021 Apr;9(4)

Department of Radiation Oncology, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, USA

Background: Numerous trials combining radiation therapy (RT) and immunotherapy in head and neck squamous cell carcinoma (HNSCC) are failing. Using preclinical immune cold models of HNSCC resistant to RT-immune checkpoint inhibitors, we investigate therapeutic approaches of overcoming such resistance by examining the differential microenvironmental response to RT.

Methods: We subjected two HPV-negative orthotopic mouse models of HNSCC to combination RT, regulatory T cells (Treg) depletion, and/or CD137 agonism. Tumor growth was measured and intratumorous and lymph node immune populations were compared among treatment groups. Human gene sets, genetically engineered mouse models and , flow and time-of-flight cytometry, RNA-Seq, Treg adoptive transfer studies, and in vitro experiments were used to further evaluate the role of dendritic cells (DCs) and Tregs in these treatments.

Results: In MOC2 orthotopic tumors, we find no therapeutic benefit to targeting classically defined immunosuppressive myeloids, which increase with RT. In these radioresistant tumors, supplementing combination RT and Treg depletion with anti-CD137 agonism stimulates CD103 DC activation in tumor-draining lymph nodes as characterized by increases in CD80 and CCR7 DCs, resulting in a CD8 T cell-dependent response. Simultaneously, Tregs are reprogrammed to an effector phenotype demonstrated by increases in interferonγ, tumor necrosis factorα, PI3K, pAKT and Eomes populations as well as decreases in CTLA4 and NRP-1 populations. Tumor eradication is observed when RT is increased to an 8 Gy x 5 hypofractionated regimen and combined with anti-CD25+ anti-CD137 treatment. In a human gene set from oral squamous cell carcinoma tumors, high Treg number is associated with earlier recurrence.

Conclusions: Regulating Treg functionality and DC activation status within the lymph node is critical for generating a T cell effector response in these highly radioresistant tumors. These findings underscore the plasticity of Tregs and represent a new therapeutic opportunity for reprogramming the tumor microenvironment in HNSCCs resistant to conventional radioimmunotherapy approaches.
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http://dx.doi.org/10.1136/jitc-2020-001955DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8061827PMC
April 2021

Optimized Detection of Acute MHV68 Infection With a Reporter System Identifies Large Peritoneal Macrophages as a Dominant Target of Primary Infection.

Front Microbiol 2021 9;12:656979. Epub 2021 Mar 9.

Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States.

Investigating the dynamics of virus-host interactions remains an important challenge, often limited by the ability to directly identify virally infected cells. Here, we utilize a beta-lactamase activated fluorescent substrate to identify primary targets of murine gammaherpesvirus 68 (MHV68) infection in the peritoneal cavity. By optimizing substrate and detection conditions, we were able to achieve multiparameter characterization of infected cells and the ensuing host response. MHV68 infection leads to a pronounced increase in immune cells, with CD8+ T cells increasing by 3 days, and total infiltrate peaking around 8 days post-infection. MHV68 infection results in near elimination of large peritoneal macrophages (LPMs) by 8 days post-infection, and a concordant increase in small peritoneal macrophages (SPMs) and monocytes. Infection is associated with prolonged changes to myeloid cells, with a distinct population of MHC II LPMs emerging by 14 days. Targets of MHV68 infection could be readily detected. Between 1 and 3 days post-infection, MHV68 infects ∼5-10% of peritoneal cells, with >75% being LPMs. By 8 days post-infection, the frequency of MHV68 infection is reduced at least 10-fold, with infection primarily in SPMs, with few infected dendritic cells and B cells. Importantly, limiting dilution analysis indicates that at 3 days post-infection, the majority of MHV68-infected cells harbor latent rather than lytic virus at frequencies consistent with those identified based on reporter gene expression. Our findings demonstrate the utility of the beta-lactamase MHV68 reporter system for high throughput single-cell analysis and identify dynamic changes during primary gammaherpesvirus infection.
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http://dx.doi.org/10.3389/fmicb.2021.656979DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7985543PMC
March 2021

Role of epidermal growth factor receptor inhibitor-induced interferon pathway signaling in the head and neck squamous cell carcinoma therapeutic response.

J Transl Med 2021 01 23;19(1):43. Epub 2021 Jan 23.

Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, 12801 E. 17th Ave, Aurora, CO, 80045, USA.

Background: Epidermal growth factor receptor (EGFR) is frequently amplified or overexpressed in head and neck squamous cell carcinoma (HNSCC) and is a clinically validated target for the therapeutic antibody, cetuximab, in the management of this cancer. The degree of response to EGFR inhibitors measured by tumor shrinkage varies widely among HNSCC patients, and the biological mechanisms that underlie therapeutic heterogeneity amongst HNSCC patients remain ill-defined.

Methods: EGFR-dependent human and murine HNSCC cell lines were treated with the EGFR/ERBB inhibitors, gefitinib and AZD8931, and submitted to RNAseq, GSEA, and qRT-PCR. Conditioned media was analyzed by ELISA and Luminex assays. Murine HNSCC tumors were stained for T cell markers by immunofluorescence. Primary HSNCC patient specimens treated with single agent cetuximab were stained with Vectra multispectral immunofluorescence.

Results: The transcriptional reprogramming response to EGFR/ERBB-specific TKIs was measured in a panel of EGFR-dependent human HNSCC cell lines and interferon (IFN) α and γ responses identified as top-ranked TKI-induced pathways. Despite similar drug sensitivity, responses among 7 cell lines varied quantitatively and qualitatively, especially regarding the induced chemokine and cytokine profiles. Of note, the anti-tumorigenic chemokine, CXCL10, and the pro-tumorigenic factor, IL6, exhibited wide-ranging and non-overlapping induction. Similarly, AZD8931 exerted potent growth inhibition, IFNα/IFNγ pathway activation, and CXCL10 induction in murine B4B8 HNSCC cells. AZD8931 treatment of immune-competent mice bearing orthotopic B4B8 tumors increased CD8 + T cell content and the therapeutic response was abrogated in nu/nu mice relative to BALB/c mice. Finally, Vectra 3.0 analysis of HNSCC patient tumors prior to and after 3-4 weeks of single agent cetuximab treatment revealed increased CD8 + T cell content in specimens from patients exhibiting a therapeutic response relative to non-responders.

Conclusions: The findings reveal heterogeneous, tumor cell-intrinsic, EGFR/ERBB inhibitor-induced IFN pathway activation in HNSCC and suggest that individual tumor responses to oncogene-targeted agents are a sum of direct growth inhibitory effects and variably-induced participation of host immune cells.
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http://dx.doi.org/10.1186/s12967-021-02706-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7825244PMC
January 2021

Tolerance induction in memory CD4 T cells is partial and reversible.

Immunology 2021 01 27;162(1):68-83. Epub 2020 Oct 27.

Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK.

Memory T cells respond rapidly in part because they are less reliant on a heightened levels of costimulatory molecules. This enables rapid control of secondary infecting pathogens but presents challenges to efforts to control or silence memory CD4 T cells, for example in antigen-specific tolerance strategies for autoimmunity. We have examined the transcriptional and functional consequences of reactivating memory CD4 T cells in the absence of an adjuvant. We find that memory CD4 T cells generated by infection or immunisation survive secondary activation with antigen delivered without adjuvant, regardless of their location in secondary lymphoid organs or peripheral tissues. These cells were, however, functionally altered following a tertiary immunisation with antigen and adjuvant, proliferating poorly but maintaining their ability to produce inflammatory cytokines. Transcriptional and cell cycle analysis of these memory CD4 T cells suggests they are unable to commit fully to cell division potentially because of low expression of DNA repair enzymes. In contrast, these memory CD4 T cells could proliferate following tertiary reactivation by viral re-infection. These data indicate that antigen-specific tolerogenic strategies must examine multiple parameters of Tcell function, and provide insight into the molecular mechanisms that may lead to deletional tolerance of memory CD4 T cells.
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http://dx.doi.org/10.1111/imm.13263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7730012PMC
January 2021

Complement factor H-deficient mice develop spontaneous hepatic tumors.

J Clin Invest 2020 08;130(8):4039-4054

Department of Medicine, Nephrology and Hypertension, University of Colorado School of Medicine, Aurora, Colorado, USA.

Hepatocellular carcinoma (HCC) is difficult to detect, carries a poor prognosis, and is one of few cancers with an increasing yearly incidence. Molecular defects in complement factor H (CFH), a critical regulatory protein of the complement alternative pathway (AP), are typically associated with inflammatory diseases of the eye and kidney. Little is known regarding the role of CFH in controlling complement activation within the liver. While studying aging CFH-deficient (fH-/-) mice, we observed spontaneous hepatic tumor formation in more than 50% of aged fH-/- males. Examination of fH-/- livers (3-24 months) for evidence of complement-mediated inflammation revealed widespread deposition of complement-activation fragments throughout the sinusoids, elevated transaminase levels, increased hepatic CD8+ and F4/80+ cells, overexpression of hepatic mRNA associated with inflammatory signaling pathways, steatosis, and increased collagen deposition. Immunostaining of human HCC biopsies revealed extensive deposition of complement fragments within the tumors. Investigating the Cancer Genome Atlas also revealed that increased CFH mRNA expression is associated with improved survival in patients with HCC, whereas mutations are associated with worse survival. These results indicate that CFH is critical for controlling complement activation in the liver, and in its absence, AP activation leads to chronic inflammation and promotes hepatic carcinogenesis.
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http://dx.doi.org/10.1172/JCI135105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7410061PMC
August 2020

Cancer cell-intrinsic expression of MHC II in lung cancer cell lines is actively restricted by MEK/ERK signaling and epigenetic mechanisms.

J Immunother Cancer 2020 04;8(1)

Anesthesiology, University of Colorado Denver - Anschutz Medical Campus, Aurora, Colorado, USA

Background: Programmed death 1/programmed death ligand 1 (PD-1/PD-L1) targeted immunotherapy affords clinical benefit in ~20% of unselected patients with lung cancer. The factor(s) that determine whether a tumor responds or fails to respond to immunotherapy remains an active area of investigation. We have previously defined divergent responsiveness of two KRAS-mutant cell lines to PD-1/PD-L1 blockade using an orthotopic, immunocompetent mouse model. Responsiveness to PD-1/PD-L1 checkpoint blockade correlates with an interferon gamma (IFNγ)-inducible gene signature and major histocompatibility complex class II (MHC II) expression by cancer cells. In the current study, we aim to identify therapeutic targets that can be manipulated in order to enhance cancer-cell-specific MHC II expression.

Methods: Responsiveness to IFNγ and induction of MHC II expression was assessed after various treatment conditions in mouse and human non-small cell lung cancer (NSCLC) cell lines using mass cytometric and flow cytometric analysis.

Results: Single-cell analysis using mass and flow cytometry demonstrated that IFNγ consistently induced PD-L1 and MHC class I (MHC I) across multiple murine and human NSCLC cell lines. In contrast, MHC II showed highly variable induction following IFNγ treatment both between lines and within lines. In mouse models of NSCLC, MHC II induction was inversely correlated with basal levels of phosphorylated extracellular signal-regulated kinase (ERK) 1/2, suggesting potential mitogen-activated protein (MAP) kinase-dependent antagonism of MHC II expression. To test this, cell lines were subjected to varying levels of stimulation with IFNγ, and assessed for MHC II expression in the presence or absence of mitogen-activated protein kinase kinase (MEK) inhibitors. IFNγ treatment in the presence of MEK inhibitors significantly enhanced MHC II induction across multiple lung cancer lines, with minimal impact on expression of either PD-L1 or MHC I. Inhibition of histone deacetylases (HDACs) also enhanced MHC II expression to a more modest extent. Combined MEK and HDAC inhibition led to greater MHC II expression than either treatment alone.

Conclusions: These studies emphasize the active inhibitory role that epigenetic and ERK signaling cascades have in restricting cancer cell-intrinsic MHC II expression in NSCLC, and suggest that combinatorial blockade of these pathways may engender new responsiveness to checkpoint therapies.
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http://dx.doi.org/10.1136/jitc-2019-000441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204826PMC
April 2020

Cancer Cell-Intrinsic Expression of MHC Class II Regulates the Immune Microenvironment and Response to Anti-PD-1 Therapy in Lung Adenocarcinoma.

J Immunol 2020 04 16;204(8):2295-2307. Epub 2020 Mar 16.

Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;

MHC class II (MHCII) expression is usually restricted to APC but can be expressed by cancer cells. We examined the effect of cancer cell-specific MHCII (csMHCII) expression in lung adenocarcinoma on T cell recruitment to tumors and response to anti-PD-1 therapy using two orthotopic immunocompetent murine models of non-small cell lung cancer: CMT167 (CMT) and Lewis lung carcinoma (LLC). We previously showed that CMT167 tumors are eradicated by anti-PD1 therapy, whereas LLC tumors are resistant. RNA sequencing analysis of cancer cells recovered from tumors revealed that csMHCII correlated with response to anti-PD1 therapy, with immunotherapy-sensitive CMT167 cells being csMHCII positive, whereas resistant LLC cells were csMHCII negative. To test the functional effects of csMHCII, MHCII expression was altered on the cancer cells through loss- and gain-of-function of CIITA, a master regulator of the MHCII pathway. Loss of CIITA in CMT167 decreased csMHCII and converted tumors from anti-PD-1 sensitive to anti-PD-1 resistant. This was associated with lower levels of Th1 cytokines, decreased T cell infiltration, increased B cell numbers, and decreased macrophage recruitment. Conversely, overexpression of CIITA in LLC cells resulted in csMHCII in vitro and in vivo. Enforced expression of CIITA increased T cell infiltration and sensitized tumors to anti-PD-1 therapy. csMHCII expression was also examined in a subset of surgically resected human lung adenocarcinomas by multispectral imaging, which provided a survival benefit and positively correlated with T cell infiltration. These studies demonstrate a functional role for csMHCII in regulating T cell infiltration and sensitivity to anti-PD-1.
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http://dx.doi.org/10.4049/jimmunol.1900778DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7472648PMC
April 2020

High-Dimensional Analysis of Postsplenectomy Peripheral Immune Cell Changes.

Immunohorizons 2020 02 18;4(2):82-92. Epub 2020 Feb 18.

Department of Surgery, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;

Although the consequences of splenectomy are well understood in mice, much less is known about the immunologic changes that occur following splenectomy in humans. We sought to characterize the circulating immune cell populations of patients before and after elective splenectomy to determine if these changes are related to postsplenectomy survival outcomes. Retrospective clinical information was collected from 95 patients undergoing elective splenectomy compared with 91 patients undergoing pancreaticoduodenectomy (Whipple procedure). We further analyzed peripheral blood from five patients in the splenectomy group, collected before and after surgery, using single-cell cytometry by time-of-flight mass spectrometry. We compared pre- and postsplenectomy data to characterize both the major and minor immune cell populations in significantly greater detail. Compared with patients undergoing a Whipple procedure, splenectomized patients had significant and long-lasting elevated counts of lymphocytes, monocytes, and basophils. Cytometry by time-of-flight mass spectroscopy analysis demonstrated that the elevated lymphocytes primarily consisted of naive CD4 T cells and a population of activated CD25CD56CD4 T cells, whereas the elevated monocyte counts were mainly mature, activated monocytes. We also observed a significant increase in the expression of the chemokine receptors CCR6 and CCR4 on several cellular populations. Taken together, these data indicate that significant immunological changes take place following splenectomy. Whereas other groups have compared splenectomized patients to healthy controls, this study compared patients undergoing elective splenectomy to those undergoing a similar major abdominal surgery. Overall, we found that splenectomy results in significant long-lasting changes in circulating immune cell populations and function.
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http://dx.doi.org/10.4049/immunohorizons.1900089DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7476217PMC
February 2020

Sphingosine-1-Phosphate Lyase Inhibition Alters the S1P Gradient and Ameliorates Crohn's-Like Ileitis by Suppressing Thymocyte Maturation.

Inflamm Bowel Dis 2020 01;26(2):216-228

Inflammatory Bowel Disease Center, Division of Gastroenterology, University of California San Diego, La Jolla, California, USA.

Background: Lymphocytes recirculate from tissues to blood following the sphingosine-1-phosphate (S1P) gradient (low in tissues, high in blood), maintained by synthetic and degradative enzymes, among which the S1P lyase (SPL) irreversibly degrades S1P. The role of SPL in the intestine, both during homeostasis and IBD, is poorly understood. We hypothesized that modulation of tissue S1P levels might be advantageous over S1P receptor (S1PR) agonists (eg, fingolimod, ozanimod, etrasimod), as without S1PR engagement there might be less likelihood of potential off-target effects.

Methods: First we examined SPL mRNA transcripts and SPL localization in tissues by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. The in vivo effects of the SPL inhibitors 4-deoxypyridoxine hydrochloride (30 mg/L) and 2-acetyl-4 (tetrahydroxybutyl)imidazole (50 mg/L) were assessed through their oral administration to adult TNF∆ARE mice, which spontaneously develop Crohn's-like chronic ileitis. The effect of SPL inhibition on circulating and tissue lymphocytes, transcriptional regulation of proinflammatory cytokines, and on the histological severity of ileitis was additionally examined. Tissue S1P levels were determined by liquid chromatography-mass spectrometry. Mechanistically, the potential effects of high S1P tissue levels on intestinal leukocyte apoptosis were assessed via terminal deoxynucleotidyl transferase dUTP nick end-labeling assay and annexin 5 staining. Finally, we examined the ability of T cells to home to the intestine, along with the effects of SPL inhibition on cellular subsets within immune compartments via flow and mass cytometry.

Results: S1P lyase was ubiquitously expressed. In the gut, immunohistochemistry predominantly localized it to small intestinal epithelia, although the lamina propria leukocyte fraction had higher mRNA transcripts. Inhibition of SPL markedly increased local intestinal S1P levels, induced peripheral lymphopenia, downregulated proinflammatory cytokines, and attenuated chronic ileitis in mice. SPL inhibition reduced T and myeloid cells in secondary lymphoid tissues and the intestine and decreased naïve T-cell recruitment. The anti-inflammatory activity of SPL inhibition was not mediated by leukocyte apoptosis, nor by interference with the homing of lymphocytes to the intestine, and was independent of its peripheral lymphopenic effect. However, SPL inhibition promoted thymic atrophy and depleted late immature T cells (CD4+CD8+ double positive), with accumulation of mature CD4+CD8- and CD4-CD8+ single-positive cells.

Conclusions: Inhibition of the S1P lyase alters the S1P gradient and attenuates chronic ileitis via central immunosuppression. SPL inhibition could represent a potential way to tame an overactive immune response during IBD and other T-cell-mediated chronic inflammatory diseases.
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http://dx.doi.org/10.1093/ibd/izz174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6943703PMC
January 2020

High-Dimensional Characterization of IL-10 Production and IL-10-Dependent Regulation during Primary Gammaherpesvirus Infection.

Immunohorizons 2019 03 21;3(3):94-109. Epub 2019 Mar 21.

Department of Anesthesiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045; and

IL-10 is a potent immunomodulatory cytokine produced by multiple cell types to restrain immune activation. Many herpesviruses use the IL-10 pathway to facilitate infection, but how endogenous IL-10 is regulated during primary infection in vivo remains poorly characterized. In this study, we infected mice with murine gammaherpesvirus 68 (γHV68) and analyzed the production and genetic contribution of IL-10 by mass cytometry (cytometry by time-of-flight) analysis. γHV68 infection elicited a breadth of effector CD4 T cells in the lungs of acutely infected mice, including a highly activated effector subset that coexpressed IFN-γ, TNF-α, and IL-10. By using IL-10 GFP transcriptional reporter mice, we identified that IL-10 was primarily expressed within CD4 T cells during acute infection in the lungs. IL10gfp-expressing CD4 T cells were highly proliferative and characterized by the expression of multiple coinhibitory receptors, including PD-1 and LAG-3. When we analyzed acute γHV68 infection of IL-10-deficient mice, we found that IL-10 limits the frequency of both myeloid and effector CD4 T cell subsets in the infected lung, with minimal changes at a distant mucosal site. These data emphasize the unique insights that high-dimensional analysis can afford in investigating antiviral immunity and provide new insights into the breadth, phenotype, and function of IL-10-expressing effector CD4 T cells during acute virus infection.
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http://dx.doi.org/10.4049/immunohorizons.1800088DOI Listing
March 2019

Multidimensional analysis of Gammaherpesvirus RNA expression reveals unexpected heterogeneity of gene expression.

PLoS Pathog 2019 06 5;15(6):e1007849. Epub 2019 Jun 5.

Department of Anesthesiology, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States of America.

Virus-host interactions are frequently studied in bulk cell populations, obscuring cell-to-cell variation. Here we investigate endogenous herpesvirus gene expression at the single-cell level, combining a sensitive and robust fluorescent in situ hybridization platform with multiparameter flow cytometry, to study the expression of gammaherpesvirus non-coding RNAs (ncRNAs) during lytic replication, latent infection and reactivation in vitro. This method allowed robust detection of viral ncRNAs of murine gammaherpesvirus 68 (γHV68), Kaposi's sarcoma associated herpesvirus and Epstein-Barr virus, revealing variable expression at the single-cell level. By quantifying the inter-relationship of viral ncRNA, viral mRNA, viral protein and host mRNA regulation during γHV68 infection, we find heterogeneous and asynchronous gene expression during latency and reactivation, with reactivation from latency identified by a distinct gene expression profile within rare cells. Further, during lytic replication with γHV68, we find many cells have limited viral gene expression, with only a fraction of cells showing robust gene expression, dynamic RNA localization, and progressive infection. Lytic viral gene expression was enhanced in primary fibroblasts and by conditions associated with enhanced viral replication, with multiple subpopulations of cells present in even highly permissive infection conditions. These findings, powered by single-cell analysis integrated with automated clustering algorithms, suggest inefficient or abortive γHV infection in many cells, and identify substantial heterogeneity in viral gene expression at the single-cell level.
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http://dx.doi.org/10.1371/journal.ppat.1007849DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6576797PMC
June 2019

Tumor-intrinsic response to IFNγ shapes the tumor microenvironment and anti-PD-1 response in NSCLC.

Life Sci Alliance 2019 06 27;2(3). Epub 2019 May 27.

Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA

Targeting PD-1/PD-L1 is only effective in ∼20% of lung cancer patients, but determinants of this response are poorly defined. We previously observed differential responses of two murine K-Ras-mutant lung cancer cell lines to anti-PD-1 therapy: CMT167 tumors were eliminated, whereas Lewis Lung Carcinoma (LLC) tumors were resistant. The goal of this study was to define mechanism(s) mediating this difference. RNA sequencing analysis of cancer cells recovered from lung tumors revealed that CMT167 cells induced an IFNγ signature that was blunted in LLC cells. Silencing in CMT167 resulted in tumors resistant to IFNγ and anti-PD-1 therapy. Conversely, LLC cells had high basal expression of SOCS1, an inhibitor of IFNγ. Silencing increased response to IFNγ in vitro and sensitized tumors to anti-PD-1. This was associated with a reshaped tumor microenvironment, characterized by enhanced T cell infiltration and enrichment of PD-L1 myeloid cells. These studies demonstrate that targeted enhancement of tumor-intrinsic IFNγ signaling can induce a cascade of changes associated with increased therapeutic vulnerability.
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http://dx.doi.org/10.26508/lsa.201900328DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6537751PMC
June 2019

Inhibition of EphB4-Ephrin-B2 Signaling Reprograms the Tumor Immune Microenvironment in Head and Neck Cancers.

Cancer Res 2019 05 20;79(10):2722-2735. Epub 2019 Mar 20.

Department of Radiation Oncology, University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado.

Identifying targets present in the tumor microenvironment that contribute to immune evasion has become an important area of research. In this study, we identified EphB4-ephrin-B2 signaling as a regulator of both innate and adaptive components of the immune system. EphB4 belongs to receptor tyrosine kinase family that interacts with ephrin-B2 ligand at sites of cell-cell contact, resulting in bidirectional signaling. We found that EphB4-ephrin-B2 inhibition alone or in combination with radiation (RT) reduced intratumoral regulatory T cells (Tregs) and increased activation of both CD8 and CD4Foxp3 T cells compared with the control group in an orthotopic head and neck squamous cell carcinoma (HNSCC) model. We also compared the effect of EphB4-ephrin-B2 inhibition combined with RT with combined anti-PDL1 and RT and observed similar tumor growth suppression, particularly at early time-points. A patient-derived xenograft model showed reduction of tumor-associated M2 macrophages and favored polarization towards an antitumoral M1 phenotype following EphB4-ephrin-B2 inhibition with RT. , EphB4 signaling inhibition decreased Ki67-expressing Tregs and Treg activation compared with the control group. Overall, our study is the first to implicate the role of EphB4-ephrin-B2 in tumor immune response. Moreover, our findings suggest that EphB4-ephrin-B2 inhibition combined with RT represents a potential alternative for patients with HNSCC and could be particularly beneficial for patients who are ineligible to receive or cannot tolerate anti-PDL1 therapy. SIGNIFICANCE: These findings present EphB4-ephrin-B2 inhibition as an alternative to anti-PDL1 therapeutics that can be used in combination with radiation to induce an effective antitumor immune response in patients with HNSCC.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-3257DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6522285PMC
May 2019

Targeting DDR2 enhances tumor response to anti-PD-1 immunotherapy.

Sci Adv 2019 02 20;5(2):eaav2437. Epub 2019 Feb 20.

Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA.

While a fraction of cancer patients treated with anti-PD-1 show durable therapeutic responses, most remain unresponsive, highlighting the need to better understand and improve these therapies. Using an in vivo screening approach with a customized shRNA pooled library, we identified DDR2 as a leading target for the enhancement of response to anti-PD-1 immunotherapy. Using isogenic in vivo murine models across five different tumor histologies-bladder, breast, colon, sarcoma, and melanoma-we show that DDR2 depletion increases sensitivity to anti-PD-1 treatment compared to monotherapy. Combination treatment of tumor-bearing mice with anti-PD-1 and dasatinib, a tyrosine kinase inhibitor of DDR2, led to tumor load reduction. RNA-seq and CyTOF analysis revealed higher CD8 T cell populations in tumors with DDR2 depletion and those treated with dasatinib when either was combined with anti-PD-1 treatment. Our work provides strong scientific rationale for targeting DDR2 in combination with PD-1 inhibitors.
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http://dx.doi.org/10.1126/sciadv.aav2437DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6382401PMC
February 2019

Aging of Antiviral CD8 Memory T Cells Fosters Increased Survival, Metabolic Adaptations, and Lymphoid Tissue Homing.

J Immunol 2019 01 14;202(2):460-475. Epub 2018 Dec 14.

Department of Anesthesiology, University of Colorado Denver, Aurora, CO 80045;

Aging of established antiviral T cell memory can foster a series of progressive adaptations that paradoxically improve rather than compromise protective CD8 T cell immunity. We now provide evidence that this gradual evolution, the pace of which is contingent on the precise context of the primary response, also impinges on the molecular mechanisms that regulate CD8 memory T cell (T) homeostasis. Over time, CD8 T generated in the wake of an acute infection with the natural murine pathogen lymphocytic choriomeningitis virus become more resistant to apoptosis and acquire enhanced cytokine responsiveness without adjusting their homeostatic proliferation rates; concurrent metabolic adaptations promote increased CD8 T quiescence and fitness but also impart the reacquisition of a partial effector-like metabolic profile; and a gradual redistribution of aging CD8 T from blood and nonlymphoid tissues to lymphatic organs results in CD8 T accumulations in bone marrow, splenic white pulp, and, particularly, lymph nodes. Altogether, these data demonstrate how temporal alterations of fundamental homeostatic determinants converge to render aged CD8 T poised for greater recall responses.
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http://dx.doi.org/10.4049/jimmunol.1801277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6358025PMC
January 2019

CD8 T cells modulate autosomal dominant polycystic kidney disease progression.

Kidney Int 2018 12 21;94(6):1127-1140. Epub 2018 Sep 21.

Department of Medicine, Division of Renal Diseases and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA; Consortium for Fibrosis Research and Translation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA. Electronic address:

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent inherited nephropathy. To date, therapies alleviating the disease have largely focused on targeting abnormalities in renal epithelial cell signaling. ADPKD has many hallmarks of cancer, where targeting T cells has brought novel therapeutic interventions. However, little is known about the role and therapeutic potential of T cells in ADPKD. Here, we used an orthologous ADPKD model, Pkd1 p.R3277C (RC), to begin to define the role of T cells in disease progression. Using flow cytometry, we found progressive increases in renal CD8 and CD4 T cells, correlative with disease severity, but with selective activation of CD8 T cells. By immunofluorescence, T cells specifically localized to cystic lesions and increased levels of T-cell recruiting chemokines (CXCL9/CXCL10) were detected by qPCR/in situ hybridization in the kidneys of mice, patients, and ADPKD epithelial cell lines. Importantly, immunodepletion of CD8 T cells from one to three months in C57Bl/6 Pkd1 mice resulted in worsening of ADPKD pathology, decreased apoptosis, and increased proliferation compared to IgG-control, consistent with a reno-protective role of CD8 T cells. Thus, our studies suggest a functional role for T cells, specifically CD8 T cells, in ADPKD progression. Hence, targeting this pathway using immune-oncology agents may represent a novel therapeutic approach for ADPKD.
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http://dx.doi.org/10.1016/j.kint.2018.06.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6319903PMC
December 2018

Host Tumor Suppressor p18 Functions as a Potent Cell-Intrinsic Inhibitor of Murine Gammaherpesvirus 68 Reactivation and Pathogenesis.

J Virol 2018 03 26;92(6). Epub 2018 Feb 26.

Immunology and Microbiology Department, University of Colorado Denver School of Medicine, Aurora, Colorado, USA

Gammaherpesviruses are common viruses associated with lifelong infection and increased disease risk. Reactivation from latency aids the virus in maintaining infection throughout the life of the host and is responsible for a wide array of disease outcomes. Previously, we demonstrated that the virus-encoded cyclin (v-cyclin) of murine gammaherpesvirus 68 (γHV68) is essential for optimal reactivation from latency in normal mice but not in mice lacking the host tumor suppressor p18 (p18). Whether p18 plays a cell-intrinsic or -extrinsic role in constraining reactivation remains unclear. Here, we generated recombinant viruses in which we replaced the viral cyclin with the cellular p18 gene (p18KI) for targeted expression of p18, specifically within infected cells. We find that the p18KI virus is similar to the cyclin-deficient virus (cycKO) in lytic infection, establishment of latency, and infected cell reservoirs. While the cycKO virus is capable of reactivation in p18-deficient mice, expression of p18 from the p18KI virus results in a profound reactivation defect. These data demonstrate that p18 limits reactivation within latently infected cells, functioning in a cell-intrinsic manner. Further, the p18KI virus showed greater attenuation of virus-induced lethal pneumonia than the cycKO virus, indicating that p18 could further restrict γHV68 pathogenesis even in p18-sufficient mice. These studies demonstrate that host p18 imposes the requirement for the viral cyclin to reactivate from latency by functioning in latently infected cells and that p18 expression is associated with decreased disease, thereby identifying p18 as a compelling host target to limit chronic gammaherpesvirus pathogenesis. Gammaherpesviruses are ubiquitous viruses associated with multiple malignancies. The propensity to cycle between latency and reactivation results in an infection that is never cleared and often difficult to treat. Understanding the balance between latency and reactivation is integral to treating gammaherpesvirus infection and associated disease outcomes. This work characterizes the role of a novel inhibitor of reactivation, host p18, thereby bringing more clarity to a complex process with significant outcomes for infected individuals.
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http://dx.doi.org/10.1128/JVI.01604-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5827403PMC
March 2018

A Beginner's Guide to Analyzing and Visualizing Mass Cytometry Data.

J Immunol 2018 01;200(1):3-22

Department of Anesthesiology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;

Mass cytometry has revolutionized the study of cellular and phenotypic diversity, significantly expanding the number of phenotypic and functional characteristics that can be measured at the single-cell level. This high-dimensional analysis platform has necessitated the development of new data analysis approaches. Many of these algorithms circumvent traditional approaches used in flow cytometric analysis, fundamentally changing the way these data are analyzed and interpreted. For the beginner, however, the large number of algorithms that have been developed, as well as the lack of consensus on best practices for analyzing these data, raise multiple questions: Which algorithm is the best for analyzing a dataset? How do different algorithms compare? How can one move beyond data visualization to gain new biological insights? In this article, we describe our experiences as recent adopters of mass cytometry. By analyzing a single dataset using five cytometry by time-of-flight analysis platforms (viSNE, SPADE, X-shift, PhenoGraph, and Citrus), we identify important considerations and challenges that users should be aware of when using these different methods and common and unique insights that can be revealed by these different methods. By providing annotated workflow and figures, these analyses present a practical guide for investigators analyzing high-dimensional datasets. In total, these analyses emphasize the benefits of integrating multiple cytometry by time-of-flight analysis algorithms to gain complementary insights into these high-dimensional datasets.
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http://dx.doi.org/10.4049/jimmunol.1701494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5765874PMC
January 2018

Complement Activation via a C3a Receptor Pathway Alters CD4 T Lymphocytes and Mediates Lung Cancer Progression.

Cancer Res 2018 01 8;78(1):143-156. Epub 2017 Nov 8.

Department of Medicine, University of Colorado Denver, Aurora, Colorado.

The complement cascade is a part of the innate immune system that acts primarily to remove pathogens and injured cells. However, complement activation is also peculiarly associated with tumor progression. Here we report mechanistic insights into this association in multiple immunocompetent orthotopic models of lung cancer. After tumor engraftment, we observed systemic activation of the complement cascade as reflected by elevated levels of the key regulator C3a. Notably, growth of primary tumors and metastases was both strongly inhibited in C3-deficient mice (C3 mice), with tumors undetectable in many subjects. Growth inhibition was associated with increased numbers of IFNγ/TNFα/IL10 CD4 and CD8 T cells. Immunodepletion of CD4 but not CD8 T cells in tumor-bearing subjects reversed the inhibitory effects of C3 deletion. Similarly, antagonists of the C3a or C5a receptors inhibited tumor growth. Investigations using multiple tumor cell lines in the orthotopic model suggested the involvement of a C3/C3 receptor autocrine signaling loop in regulating tumor growth. Overall, our findings offer functional evidence that complement activation serves as a critical immunomodulator in lung cancer progression, acting to drive immune escape via a C3/C5-dependent pathway. This provocative study suggests that inhibiting complement activation may heighten immunotherapeutic responses in lung cancer, offering findings with immediate implications, given the existing clinical availability of complement antagonists. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-0240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5810934PMC
January 2018

Neutrophil transfer of to lung epithelial cells dampens acute lung injury in mice.

Sci Transl Med 2017 Sep;9(408)

Organ Protection Program, Department of Anesthesiology, University of Colorado Denver, Aurora, CO 80045, USA.

Intercellular transfer of microRNAs can mediate communication between critical effector cells. We hypothesized that transfer of neutrophil-derived microRNAs to pulmonary epithelial cells could alter mucosal gene expression during acute lung injury. Pulmonary-epithelial microRNA profiling during coculture of alveolar epithelial cells with polymorphonuclear neutrophils (PMNs) revealed a selective increase in lung epithelial cell expression of microRNA-223 (). Analysis of PMN-derived supernatants showed activation-dependent release of and subsequent transfer to alveolar epithelial cells during coculture in vitro or after ventilator-induced acute lung injury in mice. Genetic studies indicated that deficiency was associated with severe lung inflammation, whereas pulmonary overexpression of in mice resulted in protection during acute lung injury induced by mechanical ventilation or by infection with Studies of putative gene targets implicated repression of poly(adenosine diphosphate-ribose) polymerase-1 (PARP-1) in the -dependent attenuation of lung inflammation. Together, these findings suggest that intercellular transfer of from neutrophils to pulmonary epithelial cells may dampen acute lung injury through repression of PARP-1.
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http://dx.doi.org/10.1126/scitranslmed.aah5360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5842431PMC
September 2017

The Tumor Microenvironment Regulates Sensitivity of Murine Lung Tumors to PD-1/PD-L1 Antibody Blockade.

Cancer Immunol Res 2017 09 17;5(9):767-777. Epub 2017 Aug 17.

Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.

Immune checkpoint inhibitors targeting the interaction between programmed cell death-1 (PD-1) and its ligand PD-L1 induce tumor regression in a subset of non-small cell lung cancer patients. However, clinical response rates are less than 25%. Evaluation of combinations of immunotherapy with existing therapies requires appropriate preclinical animal models. In this study, murine lung cancer cells (CMT167 and LLC) were implanted either orthotopically in the lung or subcutaneously in syngeneic mice, and response to anti-PD-1/PD-L1 therapy was determined. Anti-PD-1/PD-L1 therapy inhibited CMT167 orthotopic lung tumors by 95%. The same treatments inhibited CMT167 subcutaneous tumors by only 30% and LLC orthotopic lung tumors by 35%. CMT167 subcutaneous tumors had more Foxp3 CD4 T cells and fewer PD-1 CD4 T cells compared with CMT167 orthotopic tumors. Flow cytometric analysis also demonstrated increased abundance of PD-L1 cells in the tumor microenvironment in CMT167 tumor-bearing lungs compared with CMT167 subcutaneous tumors or LLC tumor-bearing lungs. Silencing PD-L1 expression in CMT167 cells resulted in smaller orthotopic tumors that remained sensitive to anti-PD-L1 therapy, whereas implantation of CMT167 cells into PD-L1 mice blocked orthotopic tumor growth, indicating a role for PD-L1 in both the cancer cell and the microenvironment. These findings indicate that the response of cancer cells to immunotherapy will be determined by both intrinsic properties of the cancer cells and specific interactions with the microenvironment. Experimental models that accurately recapitulate the lung tumor microenvironment are useful for evaluation of immunotherapeutic agents. .
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http://dx.doi.org/10.1158/2326-6066.CIR-16-0365DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5787226PMC
September 2017

Aging promotes acquisition of naive-like CD8+ memory T cell traits and enhanced functionalities.

J Clin Invest 2016 10 12;126(10):3942-3960. Epub 2016 Sep 12.

Protective T cell memory is an acquired trait that is contingent upon the preservation of its constituents and therefore vulnerable to the potentially deleterious effects of organismal aging. Here, however, we have found that long-term T cell memory in a natural murine host-pathogen system can substantially improve over time. Comprehensive molecular, phenotypic, and functional profiling of aging antiviral CD8+ memory T cells (CD8+ TM) revealed a pervasive remodeling process that promotes the gradual acquisition of distinct molecular signatures, of increasingly homogeneous phenotypes, and of diversified functionalities that combine to confer a CD8+ TM-autonomous capacity for enhanced recall responses and immune protection. Notably, the process of CD8+ TM aging is characterized by a progressive harmonization of memory and naive T cell traits, is broadly amenable to experimental acceleration or retardation, and serves as a constitutional component for the "rebound model" of memory T cell maturation. By casting CD8+ TM populations within the temporal framework of their slowly evolving properties, this model establishes a simple ontogenetic perspective on the principal organization of CD8+ T cell memory that may directly inform the development of improved diagnostic, prophylactic, and therapeutic modalities.
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http://dx.doi.org/10.1172/JCI88546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5096808PMC
October 2016

Suppression of Antitumor Immune Responses by Human Papillomavirus through Epigenetic Downregulation of CXCL14.

mBio 2016 05 3;7(3). Epub 2016 May 3.

Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA

Unlabelled: High-risk human papillomaviruses (HPVs) are causally associated with multiple human cancers. Previous studies have shown that the HPV oncoprotein E7 induces immune suppression; however, the underlying mechanisms remain unknown. To understand the mechanisms by which HPV deregulates host immune responses in the tumor microenvironment, we analyzed gene expression changes of all known chemokines and their receptors using our global gene expression data sets from human HPV-positive and -negative head/neck cancer and cervical tissue specimens in different disease stages. We report that, while many proinflammatory chemokines increase expression throughout cancer progression, CXCL14 is dramatically downregulated in HPV-positive cancers. HPV suppression of CXCL14 is dependent on E7 and associated with DNA hypermethylation in the CXCL14 promoter. Using in vivo mouse models, we revealed that restoration of Cxcl14 expression in HPV-positive mouse oropharyngeal carcinoma cells clears tumors in immunocompetent syngeneic mice, but not in Rag1-deficient mice. Further, Cxcl14 reexpression significantly increases natural killer (NK), CD4(+) T, and CD8(+) T cell infiltration into the tumor-draining lymph nodes in vivo In vitro transwell migration assays show that Cxcl14 reexpression induces chemotaxis of NK, CD4(+) T, and CD8(+) T cells. These results suggest that CXCL14 downregulation by HPV plays an important role in suppression of antitumor immune responses. Our findings provide a new mechanistic understanding of virus-induced immune evasion that contributes to cancer progression.

Importance: Human papillomaviruses (HPVs) are causally associated with more than 5% of all human cancers. During decades of cancer progression, HPV persists, evading host surveillance. However, little is known about the immune evasion mechanisms driven by HPV. Here we report that the chemokine CXCL14 is significantly downregulated in HPV-positive head/neck and cervical cancers. Using patient tissue specimens and cultured keratinocytes, we found that CXCL14 downregulation is linked to CXCL14 promoter hypermethylation induced by the HPV oncoprotein E7. Restoration of Cxcl14 expression in HPV-positive cancer cells clears tumors in immunocompetent syngeneic mice, but not in immunodeficient mice. Mice with Cxcl14 reexpression show dramatically increased natural killer and T cells in the tumor-draining lymph nodes. These results suggest that epigenetic downregulation of CXCL14 by HPV plays an important role in suppressing antitumor immune responses. Our findings may offer novel insights to develop preventive and therapeutic tools for restoring antitumor immune responses in HPV-infected individuals.
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http://dx.doi.org/10.1128/mBio.00270-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4959654PMC
May 2016

Age Modifies the Association Between Obesity and Mortality in Individuals Hospitalized with Severe Sepsis.

J Am Geriatr Soc 2016 04;64(4):882-3

Division of Geriatric Medicine, Department of Medicine, School of Medicine, University of Colorado, Aurora, Colorado.

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http://dx.doi.org/10.1111/jgs.14047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4843830PMC
April 2016

Aging-associated inflammation promotes selection for adaptive oncogenic events in B cell progenitors.

J Clin Invest 2015 Dec 9;125(12):4666-80. Epub 2015 Nov 9.

The incidence of cancer is higher in the elderly; however, many of the underlying mechanisms for this association remain unexplored. Here, we have shown that B cell progenitors in old mice exhibit marked signaling, gene expression, and metabolic defects. Moreover, B cell progenitors that developed from hematopoietic stem cells (HSCs) transferred from young mice into aged animals exhibited similar fitness defects. We further demonstrated that ectopic expression of the oncogenes BCR-ABL, NRAS(V12), or Myc restored B cell progenitor fitness, leading to selection for oncogenically initiated cells and leukemogenesis specifically in the context of an aged hematopoietic system. Aging was associated with increased inflammation in the BM microenvironment, and induction of inflammation in young mice phenocopied aging-associated B lymphopoiesis. Conversely, a reduction of inflammation in aged mice via transgenic expression of α-1-antitrypsin or IL-37 preserved the function of B cell progenitors and prevented NRAS(V12)-mediated oncogenesis. We conclude that chronic inflammatory microenvironments in old age lead to reductions in the fitness of B cell progenitor populations. This reduced progenitor pool fitness engenders selection for cells harboring oncogenic mutations, in part due to their ability to correct aging-associated functional defects. Thus, modulation of inflammation--a common feature of aging--has the potential to limit aging-associated oncogenesis.
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http://dx.doi.org/10.1172/JCI83024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4665776PMC
December 2015

Tissue-Resident NK Cells Mediate Ischemic Kidney Injury and Are Not Depleted by Anti-Asialo-GM1 Antibody.

J Immunol 2015 Nov 9;195(10):4973-85. Epub 2015 Oct 9.

Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045;

NK cells are innate lymphoid cells important for immune surveillance, identifying and responding to stress, infection, and/or transformation. Whereas conventional NK (cNK) cells circulate systemically, many NK cells reside in tissues where they appear to be poised to locally regulate tissue function. In the present study, we tested the contribution of tissue-resident NK (trNK) cells to tissue homeostasis by studying ischemic injury in the mouse kidney. Parabiosis experiments demonstrate that the kidney contains a significant fraction of trNK cells under homeostatic conditions. Kidney trNK cells developed independent of NFIL3 and T-bet, and they expressed a distinct cell surface phenotype as compared with cNK cells. Among these, trNK cells had reduced asialo-GM1 (AsGM1) expression relative to cNK cells, a phenotype observed in trNK cells across multiple organs and mouse strains. Strikingly, anti-AsGM1 Ab treatment, commonly used as an NK cell-depleting regimen, resulted in a robust and selective depletion of cNKs, leaving trNKs largely intact. Using this differential depletion, we tested the relative contribution of cNK and trNK cells in ischemic kidney injury. Whereas anti-NK1.1 Ab effectively depleted both trNK and cNK cells and protected against ischemic/reperfusion injury, anti-AsGM1 Ab preferentially depleted cNK cells and failed to protect against injury. These data demonstrate unanticipated specificity of anti-AsGM1 Ab depletion on NK cell subsets and reveal a new approach to study the contributions of cNK and trNK cells in vivo. In total, these data demonstrate that trNK cells play a key role in modulating local responses to ischemic tissue injury in the kidney and potentially other organs.
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http://dx.doi.org/10.4049/jimmunol.1500651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4640895PMC
November 2015

A Conserved Gammaherpesvirus Cyclin Specifically Bypasses Host p18(INK4c) To Promote Reactivation from Latency.

J Virol 2015 Nov 19;89(21):10821-31. Epub 2015 Aug 19.

Immunology and Microbiology Department, University of Colorado Denver School of Medicine, Aurora, Colorado, USA

Unlabelled: Gammaherpesviruses (GHVs) carry homologs of cellular genes, including those encoding a viral cyclin that promotes reactivation from latent infection. The viral cyclin has reduced sensitivity to host cyclin-dependent kinase inhibitors in vitro; however, the in vivo significance of this is unclear. Here, we tested the genetic requirement for the viral cyclin in mice that lack the host inhibitors p27(Kip1) and p18(INK4c), two cyclin-dependent kinase inhibitors known to be important in regulating B cell proliferation and differentiation. While the viral cyclin was essential for reactivation in wild-type mice, strikingly, it was dispensable for reactivation in mice lacking p27(Kip1) and p18(INK4c). Further analysis revealed that genetic ablation of only p18(INK4c) alleviated the requirement for the viral cyclin for reactivation from latency. p18(INK4c) regulated reactivation in a dose-dependent manner so that the viral cyclin was dispensable in p18(INK4c) heterozygous mice. Finally, treatment of wild-type cells with the cytokine BAFF, a known attenuator of p18(INK4c) function in B lymphocytes, was also able to bypass the requirement for the viral cyclin in reactivation. These data show that the gammaherpesvirus viral cyclin functions specifically to bypass the cyclin-dependent kinase inhibitor p18(INK4c), revealing an unanticipated specificity between a GHV cyclin and a single cyclin-dependent kinase inhibitor.

Importance: The gammaherpesviruses (GHVs) cause lifelong infection and can cause chronic inflammatory diseases and cancer, especially in immunosuppressed individuals. Many GHVs encode a conserved viral cyclin that is required for infection and disease. While a common property of the viral cyclins is that they resist inhibition by normal cellular mechanisms, it remains unclear how important it is that the GHVs resist this inhibition. We used a mouse GHV that either contained or lacked a viral cyclin to test whether the viral cyclin lost importance when these inhibitory pathways were removed. These studies revealed that the viral cyclin was required for optimal function in normal mice but that it was no longer required following removal or reduced function of a single cellular inhibitor. These data define a very specific role for the viral cyclin in bypassing one cellular inhibitor and point to new methods to intervene with viral cyclins.
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http://dx.doi.org/10.1128/JVI.00891-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4621100PMC
November 2015

Gammaherpesvirus small noncoding RNAs are bifunctional elements that regulate infection and contribute to virulence in vivo.

mBio 2015 Feb 17;6(1):e01670-14. Epub 2015 Feb 17.

Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USA

Unlabelled: Many viruses express noncoding RNAs (ncRNAs). The gammaherpesviruses (γHVs), including Epstein-Barr virus, Kaposi's sarcoma-associated herpesvirus, and murine γHV68, each contain multiple ncRNA genes, including microRNAs (miRNAs). While these ncRNAs can regulate multiple host and viral processes in vitro, the genetic contribution of these RNAs to infection and pathogenesis remains largely unknown. To study the functional contribution of these RNAs to γHV infection, we have used γHV68, a small-animal model of γHV pathogenesis. γHV68 encodes eight small hybrid ncRNAs that contain both tRNA-like elements and functional miRNAs. These genes are transcribed by RNA polymerase III and are referred to as the γHV68 TMERs (tRNA-miRNA-encoded RNAs). To determine the total concerted genetic contribution of these ncRNAs to γHV acute infection and pathogenesis, we generated and characterized a recombinant γHV68 strain devoid of all eight TMERs. TMER-deficient γHV68 has wild-type levels of lytic replication in vitro and normal establishment of latency in B cells early following acute infection in vivo. In contrast, during acute infection of immunodeficient mice, TMER-deficient γHV68 has reduced virulence in a model of viral pneumonia, despite having an enhanced frequency of virus-infected cells. Strikingly, expression of a single viral tRNA-like molecule, in the absence of all other virus-encoded TMERs and miRNAs, reverses both attenuation in virulence and enhanced frequency of infected cells. These data show that γHV ncRNAs play critical roles in acute infection and virulence in immunocompromised hosts and identify these RNAs as a new potential target to modulate γHV-induced infection and pathogenesis.

Importance: The gammaherpesviruses (γHVs) are a subfamily of viruses associated with chronic inflammatory diseases and cancer, particularly in immunocompromised individuals. These viruses uniformly encode multiple types of noncoding RNAs (ncRNAs) that are not translated into proteins. It remains unclear how virus-expressed ncRNAs influence the course and outcome of infection in vivo. Here, we generated a mouse γHV that lacks the expression of multiple ncRNAs. Notably, this mutant virus is critically impaired in the ability to cause disease in immunocompromised hosts yet shows a paradoxical increase in infected cells early during infection in these hosts. While the original mouse virus encodes multiple ncRNAs, the expression of a single domain of one ncRNA can partially reverse the defects of the mutant virus. These studies demonstrate that γHV ncRNAs can directly contribute to virus-induced disease in vivo and that these RNAs may be multifunctional, allowing the opportunity to specifically interfere with different functional domains of these RNAs.
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http://dx.doi.org/10.1128/mBio.01670-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4337559PMC
February 2015
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