Airway mucin secretion is necessary for ciliary clearance of inhaled particles and pathogens, but can be detrimental in pathologies such as asthma and cystic fibrosis. Exocytosis in mammals requires a Munc18 scaffolding protein, and airway secretory cells express all three Munc18 isoforms. Using conditional airway epithelial deletant mice, we found that Munc18a has the major role in baseline mucin secretion, Munc18b has the major role in stimulated mucin secretion, and Munc18c does not function in mucin secretion. In an allergic asthma model, Munc18b deletion reduced airway mucus occlusion and airflow resistance. In a cystic fibrosis model, Munc18b deletion reduced airway mucus occlusion and emphysema. Munc18b deficiency in the airway epithelium did not result in any abnormalities of lung structure, particle clearance, inflammation, or bacterial infection. Our results show that regulated secretion in a polarized epithelial cell may involve more than one exocytic machine at the apical plasma membrane, and that the protective roles of mucin secretion can be preserved while therapeutically targeting its pathologic roles.
Ana M. Jaramillo, Lucia Piccotti, Walter V. Velasco, Anna Sofia Huerta Delgado, Zoulikha Azzegagh, Felicity S. Chung, Usman I. Nazeer, Junaid Farooq, Joshua M. Brenner, Jan Parker-Thornburg, Brenton L. Scott, Christopher M. Evans, Roberto Adachi, Alan R. Burns, Silvia M. Kreda, Michael J. Tuvim, Burton F. Dickey
Type 1 diabetes (T1D) is caused by autoimmune destruction of pancreatic β cells. Mounting evidence supports a central role for β-cell alterations in triggering the activation of self-reactive T-cells in T1D. However, the early deleterious events that occur in β cells, underpinning islet autoimmunity are not known. We hypothesized that epigenetic modifications induced in β cells by inflammatory mediators play a key role in initiating the autoimmune response. We analyzed DNA methylation (DNAm) patterns and gene expression in human islets exposed to IFNα, a cytokine associated with T1D development. We found that IFNα triggers DNA demethylation and increases expression of genes controlling inflammatory and immune pathways. We then demonstrated that DNA demethylation was caused by up-regulation of the exoribonuclease, PNPase Old-35 (PNPT1), which caused degradation of miR-26a. This in turn promoted the up-regulation of ten-eleven translocation TET2 enzyme and increased 5-hydoxymethylcytosine levels in human islets and pancreatic β-cells. Moreover, we showed that specific IFNα expression in the β cells of IFNα-INS1CreERT2 transgenic mice, led to development of T1D that was preceded by increased islet DNA hydroxymethylation through a PNPT1/TET2-dependent mechanism. Our results suggest a new mechanism through which IFNα regulates DNAm in β cells, leading to changes in expression of genes in inflammatory and immune pathways that can initiate islet autoimmunity in T1D.
Mihaela Stefan-Lifshitz, Esra Karakose, Lingguang Cui, Abora Ettela, Zhengzi Yi, Weijia Zhang, Yaron Tomer
Alveolar type 2 (AT2) cell endoplasmic reticulum (ER) stress is a prominent feature in adult and pediatric interstitial lung disease (ILD and ChILD), but in vivo models linking AT2 cell ER stress to ILD have been elusive. Based on a clinical ChILD case we identified a critical cysteine residue in the Surfactant Protein C gene (SFTPC) BRICHOS domain whose mutation induced ER stress in vitro. To model this in vivo, we generated a knock-in model expressing a cysteine-to-glycine substitution at codon 121 (C121G) in the Sftpc gene. SftpcC121G expression during fetal development resulted in a toxic gain of function resulting in fatal post-natal respiratory failure from disrupted lung morphogenesis. Induced SftpcC121G expression in adult mice resulted in an ER retained pro-protein causing AT2 cell ER stress. SftpcC121G AT2 cells were a source of cytokines expressed in concert with development of a polycellular alveolitis. These cytokines were subsequently found in a high-dimensional proteomic screen of bronchoalveolar lavage fluid from ChILD patients with the same class of SFTPC mutations. Following alveolitis resolution, SftpcC121G mice developed spontaneous pulmonary fibrosis and restrictive lung impairment. This model provides proof of concept linking AT2 cell ER stress to fibrotic lung disease coupled with translationally relevant biomarkers.
Jeremy Katzen, Brandie D. Wagner, Alessandro Venosa, Meghan Kopp, Yaniv Tomer, Scott J. Russo, Alvis C. Headen, Maria C. Basil, James M. Stark, Surafel Mulugeta, Robin R. Deterding, Michael F. Beers
miR-155 has recently emerged as an important promoter of antitumor immunity through its functions in T lymphocytes. However, the impact of T cell expressed miR-155 on immune cell dynamics in solid tumors remains unclear. In the present study, we used single-cell RNA-sequencing to define the CD45+ immune cell populations at different timepoints within B16F10 murine melanoma tumors growing in either wild-type or miR-155 T cell conditional knockout (TCKO) mice. miR-155 was required for optimal T cell activation and reinforced the T cell response at the expense of infiltrating myeloid cells. Further, myeloid cells from tumors growing in TCKO mice were defined by an increase in wound healing genes and a decreased IFN-γ response gene signature. Finally, we found that miR-155 expression predicted a favorable outcome in human melanoma patients and was associated with a strong immune signature. Moreover, gene expression analysis of the Cancer Genome Atlas (TCGA) data revealed that miR-155 expression also correlates with an immune-enriched subtype in 29 other human solid tumors. Together, our study provides an unprecedented analysis of the cell types and gene expression signatures of immune cells within experimental melanoma tumors and elucidates the role of miR-155 in coordinating antitumor immune responses in mammalian tumors.
H. Atakan Ekiz, Thomas B. Huffaker, Allie H. Grossmann, W. Zac Stephens, Matthew A. Williams, June L. Round, Ryan M. O'Connell
The tumor microenvironment presents physical, immunologic, and metabolic barriers to durable immunotherapy responses. We have recently described roles for both T cell metabolic insufficiency as well as tumor hypoxia as inhibitory mechanisms which prevent T cell activity in murine tumors, but whether intratumoral T cell activity or response to immunotherapy vary between patients as a function of distinct metabolic profiles in tumor cells remains unclear. Here we show that metabolic derangement can vary widely in both degree and type in patient-derived cell lines and in ex vivo analysis of patient samples, such that some cells demonstrate solely deregulated oxidative or glycolytic metabolism. Further, deregulated oxidative, but not glycolytic, metabolism was associated with increased generation of hypoxia upon implantation into immunodeficient animals. Generation of murine single cell melanoma cell lines that lacked either oxidative or glycolytic metabolism showed that elevated tumor oxygen consumption was associated with increased T cell exhaustion and decreased immune activity. Further, melanoma lines lacking oxidative metabolism were solely responsive to anti-PD1 therapy among those tested. Prospective analysis of patient samples immunotherapy revealed that oxidative, but not glycolytic, metabolism was associated with progression on PD-1 blockade. Our data highlight a role for oxygen as a crucial metabolite required for the tumor-infiltrating T cells to differentiate appropriately upon PD-1 blockade, and suggesting tumor oxidative metabolism may be a target to improve immunotherapeutic response.
Yana G. Najjar, Ashley V. Menk, Cindy Sander, Uma Rao, Arivarasan Karunamurthy, Roma Bhatia, Shuyan Zhai, John M. Kirkwood, Greg M. Delgoffe
Beta-2 microglobulin (β2M) is a molecular chaperone for the major histocompatibility class I (MHC I) complex, hemochromatosis factor protein (HFE), and the neonatal Fc receptor (FcRn), but β2M may also have less understood chaperoneindependent functions. Elevated plasma β2M has a direct role in neurocognitive decline and is a risk factor for adverse cardiovascular events. β2M mRNA is present in platelets at very high levels and β2M is part of the activated platelet releasate. In addition to their more well studied thrombotic functions, platelets are important immune regulatory cells that release inflammatory molecules and contribute to leukocyte trafficking, activation, and differentiation. We have now found that platelet-derived β2M is a mediator of monocyte pro-inflammatory differentiation through non-canonical TGF-β receptor signaling. Circulating monocytes from mice lacking β2M only in platelets (Plt-β2M–/–) had a more pro-reparative monocyte phenotype, in part dependent on increased platelet-derived TGF-β signaling in the absence of β2M. Using a mouse myocardial infarction (MI) model, Plt-β2M–/– mice had limited post-MI pro-inflammatory monocyte responses, and instead demonstrated early pro-reparative monocyte differentiation, profibrotic myofibroblast responses, and a rapid decline in heart function compared to WT mice. These data demonstrate a novel chaperone-independent, monocyte phenotype regulatory function for platelet β2M, and that platelet-derived β2M and TGF-β have opposing roles in monocyte differentiation that may be important in tissue injury responses.
Zachary T. Hilt, Daphne N. Pariser, Sara K. Ture, Amy Mohan, Pearl Quijada, Akua Asante, Scott J. Cameron, Julie A. Sterling, Alyssa R. Merkel, Andrew L. Johanson, Jermaine L. Jenkins, Eric M. Small, Kathleen E. McGrath, James Palis, Michael R. Elliott, Craig N. Morrell
Molecular profiling of prostate cancer with liquid biopsies such as circulating tumor cells (CTC) and cell-free nucleic acid analysis yields informative yet distinct datasets. Additional insights may be gained by simultaneously interrogating multiple liquid biopsy components to construct a more comprehensive molecular disease profile. We conducted an initial proof of principle study aimed at piloting this multi-parametric approach. Peripheral blood samples from men with metastatic castrate resistant prostate cancer (mCRPC) were analyzed simultaneously for CTC enumeration, single cell copy number variation, CTC DNA and matched cell-free DNA mutations, and plasma cell-free RNA levels of androgen receptor (AR) and AR splice variant (AR-V7). In addition, liquid biopsies were compared with matched tumor profiles when available, and a second liquid biopsy was drawn and analyzed at disease progression in a subset of patients. In this manner, multiparametric liquid biopsy profiles were successfully generated for each patient and time point, demonstrating the feasibility of this approach and highlighting shared as well as unique cancer-relevant alterations. With further refinement and validation in large cohorts, multi-parametric liquid biopsies can optimally integrate disparate but clinically informative datasets and maximize their utility for molecularly directed, real-time patient management.
Emmanuelle Hodara, Gareth Morrison, Alexander T. Cunha, Daniel Zainfeld, Tong Xu, Yucheng Xu, Paul W. Dempsey, Paul C. Pagano, Farideh Bischoff, Aditi Khurana, Bonik S. Koo, Marc J. Ting, Philip D. Cotter, Matthew W. Moore, Shelly Gunn, Joshua Usher, Shahrooz Rabizadeh, Peter Danenberg, Kathleen Danenberg, John Carpten, Tanya B. Dorff, David I. Quinn, Amir Goldkorn
Soluble STimulation-2 (ST2) is increased during graft-versus-host disease (GVHD) while regulatory T cells (Tregs) that express ST2 prevent GVHD through unknown mechanisms. Transplantation of Foxp3- T cells and Tregs sorted from different Foxp3 reporter mice indicated that ST2+Tregs isolated from GVHD mice were thymus-derived and predominantly intestine localized. ST2-/- Tregs transplantation was associated with reduced total intestinal Tregs frequency and activation. ST2-/- vs wild-type intestinal Tregs transcriptomes showed decreased Treg functional markers and reciprocally, increased Rorc expression. Rorc-/- T cells transplantation enhanced the frequency and function of intestinal ST2+Tregs and reduced GVHD through decreased gut-infiltrating soluble ST2-producing type-1 and increased IL-4+IL-10+ producing type-2 T cells. Cotransfer of ST2+Tregs sorted from Rorc-/- mice with WT CD25-depleted T cells decreased GVHD severity and mortality, increased intestinal ST2+KLRG1+ Tregs and decreased type-1 T cells after transplantation, indicating an intrinsic mechanism. Ex vivo IL-33 stimulated Tregs (TregIL-33) expressed higher amphiregulin, displayed better immunosuppression, and adoptive transfer prevented GVHD better than control Tregs or TregIL-33 cultured with IL-23/IL-17. Amphiregulin blockade by neutralizing antibody in vivo abolished the protective effect of TregIL-33. Our data show an inversely expression of ST2 and RORγt in intestinal Tregs, and TregIL-33 is a potential cellular therapy avenue for preventing GVHD.
Jinfeng Yang, Abdulraouf Ramadan, Dawn K. Reichenbach, Michael Loschi, Jilu Zhang, Brad Griesenauer, Hong Liu, Keli L. Hippen, Bruce R. Blazar, Sophie Paczesny
Macrophage activation, i.e., the classical M1 and the alternative M2, plays a critical role in many pathophysiological processes, such as inflammation and tissue injury and repair. Although the regulation of macrophage activation has been under extensive investigations, there is little knowledge about the role of long non-coding RNAs (lncRNAs) in the event. In this study, we found that lncRNA Malat1 expression is distinctly regulated in differentially activated macrophages in that it is upregulated in LPS-, whereas downregulated in IL-4-treated cells. Malat1 knockdown attenuates LPS induced M1 macrophage activation. In contrast, Malat1 knockdown enhanced IL-4 activated M2 differentiation as well as macrophage pro-fibrotic phenotype. Mechanistically, Malat1 knockdown led to decreased expression of Clec16a, of which silencing phenocopied the regulatory effect of Malat1 on M1 activation. Interestingly, Malat1 knockdown promoted IL-4 induction of mitochondrial pyruvate carriers (MPCs) and their mediation of glucose derived oxidative phosphorylation (OxPhos), which was crucial to the Malat1 regulation of M2 differentiation and pro-fibrotic phenotype. Furthermore, mice with either global or conditional myeloid knockout of Malat1 demonstrated diminished LPS induced systemic and pulmonary inflammation and injury. Conversely, these mice developed more severe bleomycin induced lung fibrosis, accompanied by alveolar macrophages displaying augmented M2 and pro-fibrotic phenotype. In summary, we have identified a previously unrecognized role of Malat1 in regulation of macrophage polarization. Our data demonstrate that Malat1 is involved in pulmonary pathogeneses in association with aberrant macrophage activation.
Huachun Cui, Sami Banerjee, Sijia Guo, Na Xie, Jing Ge, Dingyuan Jiang, Martin Zörnig, Victor J. Thannickal, Gang Liu
The lymphatic system plays crucial roles in tissue homeostasis, lipid absorption and immune cell trafficking. While lymphatic valves ensure unidirectional lymph flows, the flow itself controls lymphatic valve formation. Here, we demonstrate that a mechanically activated ion channel Piezo1 senses oscillating shear stress (OSS), and incorporates the signal into the genetic program controlling lymphatic valve development and maintenance. Time-controlled deletion of Piezo1 using a pan-endothelial Cre driver (Cdh5(PAC)-CreERT2) or lymphatic-specific Cre driver (Prox1-CreERT2) equally inhibited lymphatic valve formation in newborn mouse. Furthermore, Piezo1 deletion in adult lymphatics caused substantial lymphatic valve degeneration. Piezo1 knockdown in cultured lymphatic endothelial cells (LECs) largely abrogated the OSS-induced upregulation of the lymphatic valve-signature genes. Conversely, ectopic Piezo1 overexpression upregulated the lymphatic valve genes in the absence of OSS. Remarkably, activation of Piezo1 using a chemical agonist Yoda1 not only accelerated lymphatic valve formation in animals, but also triggered upregulation of some lymphatic valve genes in cultured LECs without exposure to OSS. In summary, our studies together demonstrate that Piezo1 is the force sensor in the mechanotransduction pathway controlling lymphatic valve development and maintenance, and Piezo1 activation is a potential novel therapeutic strategy for congenital and surgery-associated lymphedema.
Dongwon Choi, Eunkyung Park, Eunson Jung, Boksik Cha, Somin Lee, James Yu, Paul M. Kim, Sunju Lee, Yeo Jin Hong, Chester J. Koh, Chang-Won Cho, Yifan Wu, Noo Li Jeon, Alex K. Wong, Laura Shin, S. Ram Kumar, Ivan Bermejo-Moreno, R. Sathish Srinivasan, Il-Taeg Cho, Young-Kwon Hong
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