The XCL1/XCR1 axis is upregulated in type 1 diabetes and aggravates its pathogenesis

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Abstract

Type 1 diabetes (T1D) is precipitated by the autoimmune destruction of the insulin-producing β-cells in the pancreatic islets of Langerhans. Chemokines have been identified as major conductors of islet infiltration by autoaggressive leukocytes, including antigen-presenting cells and islet autoantigen-specific T cells. We have previously generated a roadmap of gene expression in the islet microenvironment during T1D in a mouse model and found that most of the chemokine axes are chronically upregulated during T1D. The XCL1/XCR1 chemokine axis is of particular interest, since XCR1 is exclusively expressed on conventional dendritic cells type 1 (cDC1) that excel by their high capacity for T cell activation. Here we demonstrate cDC1 expressing XCR1 are present in and around the islets of patients with T1D and of islet-autoantibody positive individuals. Further, we show that XCL1 plays an important role in the attraction of highly potent dendritic cells expressing XCR1 to the islets in an inducible mouse model for T1D. XCL1-deficient mice display a diminished infiltration of XCR1+ cDC1 and subsequently a reduced magnitude and activity of islet autoantigen-specific T cells resulting in a profound decrease in T1D incidence. Interference with the XCL1/XCR1 chemokine axis might constitute a novel therapy for T1D.

Authors

Camilla Tondello, Christine Bender, Gregory J. Golden, Deborah Puppe, Elisa Blickberndt, Monika Bayer, Giulia K. Buchmann, Josef Pfeilschifter, Malte Bachmann, Edith Hintermann, Ralf P. Brandes, Michael R. Betts, Richard A. Kroczek, Urs Christen

Sequential JAK inhibition enhances anti-tumor immunity after combined anti-PD-1 and anti-CTLA4

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Abstract

While immune checkpoint inhibition (CPI) has reshaped cancer treatment, the majority of cancer patients do not benefit from this approach, which can also cause immune-related adverse events. Induction of IFNγ responses is thought be necessary for anti-tumor immunity, but growing evidence also implicates IFNγ as a tumor-intrinsic mediator of CPI resistance. CPI-induced IFNγ mediates activation-induced cell death in T cells as an immune-intrinsic mechanism of resistance. In this study, we show that transient block of IFNγ signaling through administration of the JAK1 inhibitor ABT-317 enhances anti-tumor T cell responses with CPI in pre-clinical models. Importantly, sequential but not concomitant ABT-317 treatment led to significantly reduced toxicity and improved tumor efficacy. Sequential treatment reduced activation-induced T cell death and enhanced expansion of tumor-reactive T cell subsets with increased effector function in vivo and ex vivo. Only CPI in combination with ABT-317 also enhanced memory responses by protecting mice from tumor rechallenge. These results demonstrate that JAK inhibition within a discrete time window following CPI addresses an immune-intrinsic mechanism of therapeutic resistance.

Authors

Marcel Arias-Badia, PeiXi Chen, Yee May Lwin, Aahir Srinath, Aram Lyu, Zenghua Fan, Serena S. Kwek, Diamond N. Luong, Ali Setayesh, Mason Sakamoto, Matthew Clark, Averey Lea, Rachel M. Wolters, Andrew Goodearl, Fiona A. Harding, Jacob V. Gorman, Wendy Ritacco, Lawrence Fong

Unique T cell signatures associated with reduced Chlamydia trachomatis reinfection in a highly exposed cohort

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Abstract

Chlamydia trachomatis (CT) is the most common bacterial sexually transmitted infection globally. Understanding natural immunity to CT will inform vaccine design. This study aimed to profile immune cells and associated functional features in CT-infected women, and determine immune profiles associated with reduced risk of ascended endometrial CT infection and CT reinfection. PBMCs from CT-exposed women were profiled by mass cytometry and random forest models identified key features that distinguish outcomes. CT+ participants exhibited higher frequencies of CD4+ Th2, Th17, and Th17 DN CD4 T effector memory (TEM) cells than uninfected participants with decreased expression of T cell activation and differentiation markers. Minimal differences were detected between women with or without endometrial CT infection. Participants who remained follow-up negative (FU-) showed higher frequencies of CD4 T central memory (TCM) Th1, Th17, Th1/17, and Th17 DN but reduced CD4 TEM Th2 cells than FU+ participants. Expression of markers associated with central memory and Th17 lineage were increased on T cell subsets among FU- participants. These data indicate that peripheral T cells exhibit distinct features associated with resistance to CT reinfection. The highly plastic Th17 lineage appears to contribute to protection. Addressing these immune nuances could promote efficacy of CT vaccines.

Authors

Kacy S. Yount, Chi-Jane Chen, Avinash Kollipara, Chuwen Liu, Neha Vivek Mokashi, Xiaojing Zheng, C Bruce Bagwell, Taylor B. Poston, Harold C. Wiesenfeld, Sharon L. Hillier, Catherine M. O'Connell, Natalie Stanley, Toni Darville

Transcriptomic responses of lung mesenchymal cells during pneumonia

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Abstract

The role of mesenchymal cells during respiratory infection is not well defined, including whether, which, and how the different types of mesenchymal cells respond. We collected all mesenchymal cells from lung single-cell suspensions of mice that were naïve (after receiving only saline vehicle), pneumonic (after intratracheal instillation of pneumococcus 24 hours previously), or resolved from infection (after non-lethal pneumococcal infections 6 weeks previously) and performed single-cell RNA sequencing. Cells clustered into five well-separated groups based on their transcriptomes: matrix fibroblasts, myofibroblasts, pericytes, smooth muscle cells, and mesothelial cells. Fibroblasts were the most abundant and could be further segregated into Pdgfra+Npnt+Ces1d+Col13a1+ alveolar fibroblasts and Cd9+Pi16+Sca1+Col14a1+ adventitial fibroblasts. The cells from naïve and resolved groups overlapped in dimension reduction plots, suggesting the mesenchymal cells returned to baseline transcriptomes after resolution. During pneumonia, all mesenchymal cells responded with altered transcriptomes, revealing a core response that had been conserved across cell types as well as distinct mesenchymal cell type-specific responses. The different subsets of fibroblasts induced similar gene sets, but the alveolar fibroblasts responded more strongly than the adventitial fibroblasts. These data demonstrated diverse and specialized immune activities of lung mesenchymal cells during pneumonia.

Authors

Alicia M. Soucy, Jourdan E. Brune, Archana Jayaraman, Anukul T. Shenoy, Filiz T. Korkmaz, Neelou S. Etesami, Bradley E. Hiller, Ian M.C. Martin, Wesley N. Goltry, Catherine T. Ha, Nicholas A. Crossland, Joshua D. Campbell, Thomas G. Beach, Katrina E. Traber, Matthew R. Jones, Lee J. Quinton, Markus Bosmann, Charles W. Frevert, Joseph P. Mizgerd

The transcription factor ZNF469 regulates collagen production in liver fibrosis

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Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD)—characterized by excess accumulation of fat in the liver—now affects one third of the world’s population. As MASLD progresses, extracellular matrix components including collagen accumulate in the liver causing tissue fibrosis, a major determinant of disease severity and mortality. To identify transcriptional regulators of fibrosis, we computationally inferred the activity of transcription factors (TFs) relevant to fibrosis by profiling the matched transcriptomes and epigenomes of 108 human liver biopsies from a deeply characterized cohort of patients spanning the full histopathologic spectrum of MASLD. CRISPR-based genetic knockout of the top 100 TFs identified ZNF469 as a regulator of collagen expression in primary human hepatic stellate cells (HSCs). Gain- and loss-of-function studies established that ZNF469 regulates collagen genes and genes involved in matrix homeostasis through direct binding to gene bodies and regulatory elements. By integrating multiomic large-scale profiling of human biopsies with extensive experimental validation we demonstrate that ZNF469 is a transcriptional regulator of collagen in HSCs. Overall, these data nominate ZNF469 as a previously unrecognized determinant of MASLD-associated liver fibrosis.

Authors

Sebastian Steinhauser, David Estoppey, Dennis P. Buehler, Yanhua Xiong, Nicolas Pizzato, Amandine Rietsch, Fabian Wu, Nelly Leroy, Tiffany Wunderlin, Isabelle Claerr, Philipp Tropberger, Miriam Müller, Alexandra Vissieres, Lindsay M. Davison, Eric H. Farber-Eger, Quinn S. Wells, Quanhu Sheng, Sebastian Bergling, Sophia A Wild, Pierre Moulin, Jiancong Liang, Wayne J. English, Brandon Williams, Judith Knehr, Marc Altorfer, Alejandro Reyes, Johannes Voshol, Craig Mickanin, Dominic Hoepfner, Florian Nigsch, Mathias Frederiksen, Charles R. Flynn, Barna D. Fodor, Jonathan D. Brown, Christian Kolter

Mitochondrial defects and metabolic vulnerabilities in Lynch syndrome-associated MSH2-deficient endometrial cancer

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Abstract

Lynch syndrome (LS), caused by inherited mutations in DNA mismatch repair genes including MSH2, carries a 60% lifetime risk of developing endometrial cancer (EC). Beyond hypermutability, mechanisms driving LS-associated EC remain unclear. We investigated MSH2 loss in EC pathogenesis using a mouse model (PR-Cre Msh2LoxP/LoxP, abbreviated Msh2KO), primary cell lines, human tissues, and human EC cells with isogenic MSH2 knockdown. By eight months, 58% of Msh2KO mice developed endometrial atypical hyperplasia (AH), a precancerous lesion. At 12-16 months, 47% of Msh2KO mice exhibited either AH or ECs with histologic similarities to human LS-ECs. Transcriptomic profiling of EC from Msh2KO mice revealed mitochondrial dysfunction-related pathway alterations. Subsequent studies in vitro and in vivo revealed mitochondrial dysfunction based upon two mechanisms: mitochondrial content reduction and structural disruptions in retained mitochondria. Human LS-ECs also exhibited mitochondrial content reduction compared to non-LS-ECs. Functional studies demonstrated metabolic reprogramming of MSH2-deficient EC cells, including reduced oxidative phosphorylation and increased susceptibility to glycolysis suppression. These findings identified mitochondrial dysfunction and metabolic disruption as consequences of MSH2 deficiency in EC. Mitochondrial and metabolic aberrations should be evaluated as biomarkers for endometrial carcinogenesis or risk stratification and represent potential targets for cancer interception in women with LS.

Authors

Mikayla Borthwick Bowen, Brenda Melendez, Qian Zhang, Diana Moreno, Leah Peralta, Wai-Kin Chan, Collene Jeter, Lin Tan, M. Anna Zal, Philip L. Lorenzi, Kenneth Dunner Jr., Richard K. Yang, Russell R. Broaddus, Joseph Celestino, Nisha Gokul, Elizabeth Whitley, Deena M. Scoville, Tae Hoon KIM, Jae-Wook Jeong, Rosemarie Schmandt, Karen Lu, Hyun-Eui Kim, Melinda S. Yates

Complement activation at the interface between adipocytes and cancer cells drives tumor progression

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Abstract

The omentum is the primary site of metastasis for ovarian cancer (OC). Interactions between cancer cells and adipocytes drive an invasive and pro-metastatic phenotype. Here we studied cancer cell-adipocyte crosstalk by using a direct co-culture model with immortalized human visceral pre-adipocytes (VNPAD) and OC cells. We demonstrate increased proliferation, invasiveness, and resistance to cisplatin of co-cultured compared to mono-cultured OC cells. RNA-sequencing of OC cells from co-culture vs. mono-culture revealed significant transcriptomic changes, identifying over 200 differentially expressed genes (DEGs) common to OVCAR5 and OVCAR8 cell lines. Enriched pathways included PI3K/AKT and Complement activation. Lipid transfer into OC cells from adipocytes induced upregulation of complement C3 and C5 proteins. Inhibiting C3 or C5 reversed the invasive phenotype and C3 knockdown reduced tumor progression in-vivo. Increased C3 expression was observed in omental implants compared to primary ovarian tumors and C3 secretion was higher in OC ascites from high BMI vs. low BMI patients. C3 upregulation in OC cells involved activation of ATF4-mediated integrated stress response (ISR). Overall, adipocyte-cancer cell interactions promote invasiveness and tumorigenesis via lipid transfer, activating ISR, and upregulating complement proteins C3 and C5.

Authors

Andres Valdivia, Ana Isac, Horacio Cardenas, Guangyuan Zhao, Yaqi Zhang, Hao Huang, Jian-Jun Wei, Mauricio Cuello-Fredes, Sumie Kato, Fernán Gómez-Valenzuela, Francoise A. Gourronc, Aloysius J. Klingelhutz, Daniela Matei

CD103⁺ dendritic cell — fibroblast crosstalk via TLR9, TDO2, and AHR signaling drives lung fibrogenesis

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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

Impact of aging on pulmonary cellular responses during mechanical ventilation

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Abstract

Acute respiratory distress syndrome (ARDS) results in significant morbidity and mortality, especially in the elderly. Mechanical ventilation, a common supportive treatment for ARDS, is necessary for maintaining gas exchange, but can also propagate injury. We hypothesized that aging leads to alterations in surfactant function, inflammatory signaling, and microvascular permeability within the lung during mechanical ventilation. Young and aged male mice were mechanically ventilated, and surfactant function, inflammation, and vascular permeability were assessed. Additionally, single-cell RNA sequencing was used to delineate cell-specific transcriptional changes. The results showed that in aged mice, surfactant dysfunction and vascular permeability were significantly augmented, while inflammation was less pronounced. Differential gene expression and pathway analyses revealed that alveolar macrophages in aged mice showed a blunted inflammatory response, while aged endothelial cells exhibited altered cell-cell junction formation. In vitro functional analysis revealed that aged endothelial cells had an impaired ability to form a barrier. These results highlight the complex interplay between aging and mechanical ventilation, including an age-related predisposition to endothelial barrier dysfunction, due to altered cell-cell junction formation, and decreased inflammation, potentially due to immune exhaustion. It is concluded that age-related vascular changes may underlie the increased susceptibility to injury during mechanical ventilation in elderly patients.

Authors

Aminmohamed Manji, Lefeng Wang, Cynthia M. Pape, Lynda A. McCaig, Alexandra Troitskaya, Onon Batnyam, Leah J.J. McDonald, C. Thomas Appleton, Ruud A.W. Veldhuizen, Sean E. Gill

Quinolinic acid potentially links kidney injury to brain toxicity

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Abstract

Kidney dysfunction often leads to neurological impairment, yet the complex kidney-brain relationship remains elusive. We employed spatial and bulk metabolomics to investigate a mouse model of rapid kidney failure induced by Mdm2 conditional deletion in the kidney tubules to interrogate kidney and brain metabolism. Pathway enrichment analysis of focused plasma metabolomics panel pinpointed tryptophan metabolism as the most altered pathway with kidney failure. Spatial metabolomics showed toxic tryptophan metabolites in the kidneys and brains, revealing a connection between advanced kidney disease and accelerated kynurenine degradation. In particular, the excitotoxic metabolite quinolinic acid was localized in ependymal cells in the setting of kidney failure. These findings were associated with brain inflammation and cell death. Separate mouse models of ischemia-induced acute kidney injury and adenine-induced chronic kidney disease also exhibited systemic inflammation and accumulating toxic tryptophan metabolites. Patients with advanced CKD (stage 3B-4, n = 18 and stage 5, n = 8), similarly demonstrated elevated plasma kynurenine metabolites and quinolinic acid was uniquely correlated with fatigue and reduced quality of life. Overall, our study identifies the kynurenine pathway as a bridge between kidney decline, systemic inflammation, and brain toxicity, offering potential avenues for diagnosis and treatment of neurological issues in kidney disease.

Authors

Afaf Saliba, Subrata Debnath, Ian Tamayo, Hak Joo Lee, Nagarjunachary Ragi, Falguni Das, Richard Montellano, Jana Tumova, Meyer Maddox, Esmeralda Trevino, Pragya Singh, Caitlyn Fastenau, Soumya Maity, Guanshi Zhang, Leila Hejazi, Manjeri A. Venkatachalam, Jason C. O'Connor, Bernard Fongang, Sarah C. Hopp, Kevin F. Bieniek, James D. Lechleiter, Kumar Sharma