Latest issue: November 14, 2019

In the issue

Abstract

To develop a systems biology model of fibrosis progression within the human lung we performed RNA sequencing and microRNA analysis on 95 samples obtained from 10 idiopathic pulmonary fibrosis (IPF) and 6 control lungs. Extent of fibrosis in each sample was assessed by microCT-measured alveolar surface density (ASD) and confirmed by histology. Regulatory gene expression networks were identified using linear mixed-effect models and dynamic regulatory events miner (DREM). Differential gene expression analysis identified a core set of genes increased or decreased before fibrosis was histologically evident that continued to change with advanced fibrosis. DREM generated a systems biology model (www.sb.cs.cmu.edu/IPFReg) that identified progressively divergent gene expression tracks with microRNAs and transcription factors that specifically regulate mild or advanced fibrosis. We confirmed model predictions by demonstrating that expression of POU2AF1, previously unassociated with lung fibrosis but proposed by the model as regulator, is increased in B lymphocytes in IPF lungs and that POU2AF1-knockout mice were protected from bleomycin-induced lung fibrosis. Our results reveal distinct regulation of gene expression changes in IPF tissue that remained structurally normal compared with moderate or advanced fibrosis and suggest distinct regulatory mechanisms for each stage.

Authors

John E. McDonough, Farida Ahangari, Qin Li, Siddhartha Jain, Stijn E. Verleden, Jose Herazo-Maya, Milica Vukmirovic, Giuseppe DeIuliis, Argyrios Tzouvelekis, Naoya Tanabe, Fanny Chu, Xiting Yan, Johny Verschakelen, Robert J. Homer, Dimitris V. Manatakis, Junke Zhang, Jun Ding, Karen Maes, Laurens De Sadeleer, Robin Vos, Arne Neyrinck, Panayiotis V. Benos, Ziv Bar-Joseph, Dean Tantin, James C. Hogg, Bart M. Vanaudenaerde, Wim A. Wuyts, Naftali Kaminski

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Abstract

Cardiomyopathies are complex heart muscle diseases that can be inherited or acquired. Dilated cardiomyopathy can result from mutations in LMNA, encoding the nuclear intermediate filament proteins lamin A/C. Some LMNA mutations lead to accumulation of the lamin A precursor, prelamin A, which is disease causing in a number of tissues, yet its impact upon the heart is unknown. Here, we discovered myocardial prelamin A accumulation occurred in a case of dilated cardiomyopathy, and we show that a potentially novel mouse model of cardiac-specific prelamin A accumulation exhibited a phenotype consistent with inflammatory cardiomyopathy, which we observed to be similar to HIV-associated cardiomyopathy, an acquired disease state. Numerous HIV protease therapies are known to inhibit ZMPSTE24, the enzyme responsible for prelamin A processing, and we confirmed that accumulation of prelamin A occurred in HIV+ patient cardiac biopsies. These findings (a) confirm a unifying pathological role for prelamin A common to genetic and acquired cardiomyopathies; (b) have implications for the management of HIV patients with cardiac disease, suggesting protease inhibitors should be replaced with alternative therapies (i.e., nonnucleoside reverse transcriptase inhibitors); and (c) suggest that targeting inflammation may be a useful treatment strategy for certain forms of inherited cardiomyopathy.

Authors

Daniel Brayson, Andrea Frustaci, Romina Verardo, Cristina Chimenti, Matteo Antonio Russo, Robert Hayward, Sadia Munir Ahmad, Gema Vizcay-Barrena, Andrea Protti, Peter S. Zammit, Cristobal G. dos Remedios, Elisabeth Ehler, Ajay M. Shah, Catherine M. Shanahan

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Abstract

Anemia of β-thalassemia is caused by ineffective erythropoiesis and reduced red cell survival. Several lines of evidence indicate that iron/heme restriction is a potential therapeutic strategy for the disease. Glycine is a key initial substrate for heme and globin synthesis. We provide evidence that bitopertin, a glycine transport inhibitor administered orally, improves anemia, reduces hemolysis, diminishes ineffective erythropoiesis, and increases red cell survival in a mouse model of β-thalassemia (Hbbth3/+ mice). Bitopertin ameliorates erythroid oxidant damage, as indicated by a reduction in membrane-associated free α-globin chain aggregates, in reactive oxygen species cellular content, in membrane-bound hemichromes, and in heme-regulated inhibitor activation and eIF2α phosphorylation. The improvement of β-thalassemic ineffective erythropoiesis is associated with diminished mTOR activation and Rab5, Lamp1, and p62 accumulation, indicating an improved autophagy. Bitopertin also upregulates liver hepcidin and diminishes liver iron overload. The hematologic improvements achieved by bitopertin are blunted by the concomitant administration of the iron chelator deferiprone, suggesting that an excessive restriction of iron availability might negate the beneficial effects of bitopertin. These data provide important and clinically relevant insights into glycine restriction and reduced heme synthesis strategies for the treatment of β-thalassemia.

Authors

Alessandro Matte, Enrica Federti, Michael Winter, Annette Koerner, Anja Harmeier, Norman Mazer, Tomas Tomka, Maria Luisa Di Paolo, Luigia Defalco, Immacolata Andolfo, Elisabetta Beneduce, Achille Iolascon, Alejandra Macias-Garcia, Jane-Jane Chen, Anne Janin, Christhophe Lebouef, Franco Turrini, Carlo Brugnara, Lucia De Franceschi

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Abstract

Von Hippel–Lindau (Vhl) protein inhibits hypoxia-inducible factor (Hif), yet its deletion in murine retina does not cause the extensive angiogenesis expected with Hif induction. The mechanism is unclear. Here we show that retinoblastoma tumor suppressor (Rb1) constrains expression of Hif target genes in the Vhl–/– retina. Deleting Rb1 induced extensive retinal neovascularization and autophagic ablation of photoreceptors in the Vhl–/– retina. RNA-sequencing, ChIP, and reporter assays showed Rb1 recruitment to and repression of certain Hif target genes. Activating Rb1 by deleting cyclin D1 induced a partial defect in the retinal superficial vascular plexus. Unexpectedly, removing Vhl suppressed retinoblastoma formation in murine Rb1/Rbl1–deficient retina but generated subretinal vascular growths resembling retinal angiomatous proliferation (RAP) and retinal capillary hemangioblastoma (RCH). Most stromal cells in the RAP/RCH–like lesions were Sox9+, suggesting a Müller glia origin, and expressed Lgals3, a marker of human brain hemangioblastoma. Thus, the Rb family limit Hif target gene expression in the Vhl–/– retina, and removing this inhibitory signal generates new models for RAP and RCH.

Authors

Ran Wei, Xiang Ren, Hongyu Kong, Zhongping Lv, Yongjiang Chen, Yunjing Tang, Yujiao Wang, Lirong Xiao, Tao Yu, Sabiha Hacibekiroglu, Chen Liang, Andras Nagy, Rod Bremner, Danian Chen

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Abstract

Glomerular disease is characterized by proteinuria and glomerulosclerosis, two pathologic features caused by podocyte injury and mesangial cell activation, respectively. However, whether these two events are linked remains elusive. Here, we report that sonic hedgehog (Shh) is the mediator that connects podocyte damage to mesangial activation and glomerulosclerosis. Shh was induced in glomerular podocytes in various models of proteinuric chronic kidney diseases (CKD). However, mesangial cells in the glomeruli, but not podocytes, responded to hedgehog ligand. In vitro, Shh was induced in podocytes after injury and selectively promoted mesangial cell activation and proliferation. In a miniorgan culture of isolated glomeruli, Shh promoted mesangial activation but did not affect the integrity of podocytes. Podocyte-specific ablation of Shh in vivo exhibited no effect on proteinuria after adriamycin injection but hampered mesangial activation and glomerulosclerosis. Consistently, pharmacologic blockade of Shh signaling decoupled proteinuria from glomerulosclerosis. In humans, Shh was upregulated in glomerular podocytes in patients with CKD and its circulating level was associated with glomerulosclerosis but not proteinuria. These studies demonstrate that Shh mechanistically links podocyte injury to mesangial activation in the pathogenesis of glomerular diseases. Our findings also illustrate a crucial role for podocyte-mesangial communication in connecting proteinuria to glomerulosclerosis.

Authors

Dong Zhou, Haiyan Fu, Yang Han, Lu Zhang, Shijia Liu, Lin Lin, Donna B. Stolz, Youhua Liu

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Abstract

BACKGROUND Innate immune activation impacts lung transplant outcomes. Dectin-1 is an innate receptor important for pathogen recognition. We hypothesized that genotypes reducing dectin-1 activity would be associated with infection, graft dysfunction, and death in lung transplant recipients.METHODS We assessed the rs16910526 CLEC7A gene polymorphism Y238X, which results in dectin-1 truncation, in 321 lung allograft recipients at a single institution and in 1,129 lung allograft recipients in the multicenter Lung Transplant Outcomes Group (LTOG) cohort. Differences in dectin-1 mRNA, cytokines, protein levels, immunophenotypes, and clinical factors were assessed.RESULTS Y238X carriers had decreased dectin-1 mRNA expression (P = 0.0001), decreased soluble dectin-1 protein concentrations in bronchoalveolar lavage (P = 0.008) and plasma (P = 0.04), and decreased monocyte surface dectin-1 (P = 0.01) compared with wild-type subjects. Y238X carriers had an increased risk of fungal pathogens (HR 1.17, CI 1.0–1.4), an increased risk of graft dysfunction or death (HR 1.6, CI 1.0–2.6), as well increased mortality in the UCSF cohort (HR 1.8, CI 1.1–3.8) and in the LTOG cohort (HR 1.3, CI 1.1–1.6), compared with wild-type CLEC7A subjects.CONCLUSION Increased rates of graft dysfunction and death associated with this dectin-1 polymorphism may be amplified by immunosuppression that drives higher fungal burden from compromised pathogen recognition.FUNDING The UCSF Nina Ireland Program for Lung Health Innovative Grant program, the Clinical Sciences Research & Development Service of the VA Office of Research and Development, and the Joel D. Cooper Career Development Award from the International Society for Heart and Lung Transplantation.

Authors

Daniel R. Calabrese, Ping Wang, Tiffany Chong, Jonathan Hoover, Jonathan P. Singer, Dara Torgerson, Steven R. Hays, Jeffrey A. Golden, Jasleen Kukreja, Daniel Dugger, Jason D. Christie, LTOG investigators, John R. Greenland

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Abstract

BACKGROUND Myeloid-derived suppressor cells (MDSCs) are elevated in the circulation of patients with glioblastoma (GBM), present in tumor tissue, and associated with poor prognosis. While low-dose chemotherapy reduces MDSCs in preclinical models, the use of this strategy to reduce MDSCs in GBM patients has yet to be evaluated.METHODS A phase 0/I dose-escalation clinical trial was conducted in patients with recurrent GBM treated 5–7 days before surgery with low-dose chemotherapy via capecitabine, followed by concomitant low-dose capecitabine and bevacizumab. Clinical outcomes, including progression-free and overall survival, were measured, along with safety and toxicity profiles. Over the treatment time course, circulating MDSC levels were measured by multiparameter flow cytometry, and tumor tissue immune profiles were assessed via time-of-flight mass cytometry.RESULTS Eleven patients total were enrolled across escalating dose cohorts of 150, 300, and 450 mg bid. No serious adverse events related to the drug combination were observed. Compared with pretreatment baseline, circulating MDSCs were found to be higher after surgery in the 150-mg treatment arm and lower in the 300-mg and 450-mg treatment arms. Increased cytotoxic immune infiltration was observed after low-dose capecitabine compared with untreated GBM patients in the 300-mg and 450-mg treatment arms.CONCLUSIONS Low-dose, metronomic capecitabine in combination with bevacizumab was well tolerated in GBM patients and was associated with a reduction in circulating MDSC levels and an increase in cytotoxic immune infiltration into the tumor microenvironment.TRIAL REGISTRATION ClinicalTrials.gov NCT02669173.FUNDING This research was funded by the Cleveland Clinic, Case Comprehensive Cancer Center, the Musella Foundation, B*CURED, the NIH, the National Cancer Institute, the Sontag Foundation, Blast GBM, the James B. Pendleton Charitable Trust, and the Dr. Miriam and Sheldon G. Adelson Medical Research Foundation. Capecitabine was provided in kind by Mylan Pharmaceuticals.

Authors

David M. Peereboom, Tyler J. Alban, Matthew M. Grabowski, Alvaro G. Alvarado, Balint Otvos, Defne Bayik, Gustavo Roversi, Mary McGraw, Pengjing Huang, Alireza M. Mohammadi, Harley I. Kornblum, Tomas Radivoyevitch, Manmeet S. Ahluwalia, Michael A. Vogelbaum, Justin D. Lathia

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Abstract

Previous work has reported the important links between cellular bioenergetics and the development of chronic kidney disease, highlighting the potential for targeting metabolic functions to regulate disease progression. More recently, it has been shown that alterations in fatty acid oxidation (FAO) can have an important impact on the progression of kidney disease. In this work, we demonstrate that loss of miR-33, an important regulator of lipid metabolism, can partially prevent the repression of FAO in fibrotic kidneys and reduce lipid accumulation. These changes were associated with a dramatic reduction in the extent of fibrosis induced in 2 mouse models of kidney disease. These effects were not related to changes in circulating leukocytes because bone marrow transplants from miR-33–deficient animals did not have a similar impact on disease progression. Most important, targeted delivery of miR-33 peptide nucleic acid inhibitors to the kidney and other acidic microenvironments was accomplished using pH low insertion peptides as a carrier. This was effective at both increasing the expression of factors involved in FAO and reducing the development of fibrosis. Together, these findings suggest that miR-33 may be an attractive therapeutic target for the treatment of chronic kidney disease.

Authors

Nathan L. Price, Verónica Miguel, Wen Ding, Abhishek K. Singh, Shipra Malik, Noemi Rotllan, Anna Moshnikova, Jakub Toczek, Caroline Zeiss, Mehran M. Sadeghi, Noemi Arias, Ángel Baldán, Oleg A. Andreev, Diego Rodríguez-Puyol, Raman Bahal, Yana K. Reshetnyak, Yajaira Suárez, Carlos Fernández-Hernando, Santiago Lamas

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Abstract

The transcriptional activator IκBζ is a key regulator of psoriasis, but which cells mediate its pathogenic effect remains unknown. Here we found that IκBζ expression in keratinocytes triggers not only skin lesions but also systemic inflammation in mouse psoriasis models. Specific depletion of IκBζ in keratinocytes was sufficient to suppress the induction of imiquimod- or IL-36–mediated psoriasis. Moreover, IκBζ ablation in keratinocytes prevented the onset of psoriatic lesions and systemic inflammation in keratinocyte-specific IL-17A–transgenic mice. Mechanistically, this psoriasis protection was mediated by IκBζ deficiency in keratinocytes abrogating the induction of specific proinflammatory target genes, including Cxcl5, Cxcl2, Csf2, and Csf3, in response to IL-17A or IL-36. These IκBζ-dependent genes trigger the generation and recruitment of neutrophils and monocytes that are needed for skin inflammation. Consequently, our data uncover a surprisingly pivotal role of keratinocytes and keratinocyte-derived IκBζ as key mediators of psoriasis and psoriasis-related systemic inflammation.

Authors

Sebastian Lorscheid, Anne Müller, Jessica Löffler, Claudia Resch, Philip Bucher, Florian C. Kurschus, Ari Waisman, Knut Schäkel, Stephan Hailfinger, Klaus Schulze-Osthoff, Daniela Kramer

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Abstract

While gene transfer using recombinant adeno-associated viral (rAAV) vectors has shown success in some clinical trials, there remain many tissues that are not well transduced. Because of the recent success in reprogramming islet-derived cells into functional β cells in animal models, we constructed 2 highly complex barcoded replication competent capsid shuffled libraries and selected for high-transducing variants on primary human islets. We describe the generation of a chimeric AAV capsid (AAV-KP1) that facilitates transduction of primary human islet cells and human embryonic stem cell–derived β cells with up to 10-fold higher efficiency compared with previously studied best-in-class AAV vectors. Remarkably, this chimeric capsid also enabled transduction of both mouse and human hepatocytes at very high levels in a humanized chimeric mouse model, thus providing a versatile vector that has the potential to be used in both preclinical testing and human clinical trials for liver-based diseases and diabetes.

Authors

Katja Pekrun, Gustavo De Alencastro, Qing-Jun Luo, Jun Liu, Youngjin Kim, Sean Nygaard, Feorillo Galivo, Feijie Zhang, Ren Song, Matthew R. Tiffany, Jianpeng Xu, Matthias Hebrok, Markus Grompe, Mark A. Kay

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Abstract

Although oxidative stress plays central roles in postischemic renal injury, region-specific alterations in energy and redox metabolism caused by short-duration ischemia remain unknown. Imaging mass spectrometry enabled us to reveal spatial heterogeneity of energy and redox metabolites in the postischemic murine kidney. After 10-minute ischemia and 24-hour reperfusion (10mIR), in the cortex and outer stripes of the outer medulla, ATP substantially decreased, but not in the inner stripes of the outer medulla and inner medulla. 10mIR caused renal injury with elevation of fractional excretion of sodium, although histological damage by oxidative stress was limited. Ischemia-induced NADH elevation in the cortex indicated prolonged production of reactive oxygen species by xanthine oxidase (XOD). However, consumption of reduced glutathione after reperfusion suggested the amelioration of oxidative stress. An XOD inhibitor, febuxostat, which blocks the degradation pathway of adenine nucleotides, promoted ATP recovery and exerted renoprotective effects in the postischemic kidney. Because effects of febuxostat were canceled by silencing of the hypoxanthine phosphoribosyl transferase 1 gene in cultured tubular cells, mechanisms for the renoprotective effects appear to involve the purine salvage pathway, which uses hypoxanthine to resynthesize adenine nucleotides, including ATP. These findings suggest a novel therapeutic approach for acute ischemia/reperfusion renal injury with febuxostat through salvaging high-energy adenine nucleotides.

Authors

Kentaro Fujii, Akiko Kubo, Kazutoshi Miyashita, Masaaki Sato, Aika Hagiwara, Hiroyuki Inoue, Masaki Ryuzaki, Masanori Tamaki, Takako Hishiki, Noriyo Hayakawa, Yasuaki Kabe, Hiroshi Itoh, Makoto Suematsu

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Abstract

Thymic stromal lymphopoietin (TSLP) is a cytokine mainly released by epithelial cells that plays important roles in inflammation, autoimmune disease, and cancer. While TSLP is expressed in the liver at high levels, the role of TSLP in liver ischemia/reperfusion (I/R) injury remains unknown. Experiments were carried out to determine the role of TSLP in liver I/R injury. Wild-type (WT) and TSLP receptor–knockout (TSLPR–/–) mice were subjected to liver partial warm I/R injury. Liver injury was assessed by measuring serum alanine aminotransferase (ALT) level, necrotic areas by liver histology, hepatocyte death, and local hepatic inflammatory responses. Signal pathways were explored in vivo and in vitro to identify possible mechanisms for TSLP in I/R injury. TSLP and TSLPR protein expression increased during liver I/R in vivo and following hepatocyte hypoxia/reoxygenation in vitro. Deletion of TSLPR or neutralization of TSLP with anti-TSLP antibody exacerbated liver injury in terms of serum ALT levels as well as necrotic areas in liver histology. Administration of exogenous recombinant mouse TSLP to WT mice significantly reduced liver damage compared with controls, but failed to prevent I/R injury in TSLPR–/– mice. TSLP induced autophagy in hepatocytes during liver I/R injury. Mechanistically, Akt was activated in WT mice during liver I/R injury. The opposite results were observed in TSLPR–/– mice. In addition, TSLP could directly induce Akt activation in hepatocytes independent of nonparenchymal cells in vitro. Furthermore, the Akt agonist, insulin-like growth factor-1 (IGF-1), prevented I/R injury in TSLPR–/– mice and an Akt inhibitor, LY294002, blocked the protective effects of TSLP in WT mice subjected to I/R. Our data indicate that TSLP protects against liver I/R injury via activation of the PI3K/Akt pathway. Through this pathway, TSLP induces autophagy in hepatocytes. Thus, TSLP is a potent inhibitor of stress-induced hepatocyte necrosis.

Authors

Shilai Li, Zhongjie Yi, Meihong Deng, Melanie J. Scott, Chenxuan Yang, Wenbo Li, Zhao Lei, Nicole M. Santerre, Patricia Loughran, Timothy R. Billiar

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Abstract

The adult mammalian heart regenerates poorly after injury and, as a result, ischemic heart diseases are among the leading causes of death worldwide. The recovery of the injured heart is dependent on orchestrated repair processes including inflammation, fibrosis, cardiomyocyte survival, proliferation, and contraction properties that could be modulated in patients. In this work we designed an automated high-throughput screening system for small molecules that induce cardiomyocyte proliferation in vitro and identified the small molecule Chicago Sky Blue 6B (CSB). Following induced myocardial infarction, CSB treatment reduced scar size and improved heart function of adult mice. Mechanistically, we show that although initially identified using in vitro screening for cardiomyocyte proliferation, in the adult mouse CSB promotes heart repair through (i) inhibition of CaMKII signaling, which improves cardiomyocyte contractility; and (ii) inhibition of neutrophil and macrophage activation, which attenuates the acute inflammatory response, thereby contributing to reduced scarring. In summary, we identified CSB as a potential therapeutic agent that enhances cardiac repair and function by suppressing postinjury detrimental processes, with no evidence for cardiomyocyte renewal.

Authors

Oren Yifa, Karen Weisinger, Elad Bassat, Hanjun Li, David Kain, Haim Barr, Noga Kozer, Alexander Genzelinakh, Dana Rajchman, Tamar Eigler, Kfir Baruch Umansky, Daria Lendengolts, Ori Brener, Nenad Bursac, Eldad Tzahor

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Abstract

BACKGROUND Bilateral loss of vestibular (inner ear inertial) sensation causes chronically blurred vision during head movement, postural instability, and increased fall risk. Individuals who fail to compensate despite rehabilitation therapy have no adequate treatment options. Analogous to hearing restoration via cochlear implants, prosthetic electrical stimulation of vestibular nerve branches to encode head motion has garnered interest as a potential treatment, but prior studies in humans have not included continuous long-term stimulation or 3D binocular vestibulo-ocular reflex (VOR) oculography, without which one cannot determine whether an implant selectively stimulates the implanted ear’s 3 semicircular canals.METHODS We report binocular 3D VOR responses of 4 human subjects with ototoxic bilateral vestibular loss unilaterally implanted with a Labyrinth Devices Multichannel Vestibular Implant System vestibular implant, which provides continuous, long-term, motion-modulated prosthetic stimulation via electrodes in 3 semicircular canals.RESULTS Initiation of prosthetic stimulation evoked nystagmus that decayed within 30 minutes. Stimulation targeting 1 canal produced 3D VOR responses approximately aligned with that canal’s anatomic axis. Targeting multiple canals yielded responses aligned with a vector sum of individual responses. Over 350–812 days of continuous 24 h/d use, modulated electrical stimulation produced stable VOR responses that grew with stimulus intensity and aligned approximately with any specified 3D head rotation axis.CONCLUSION These results demonstrate that a vestibular implant can selectively, continuously, and chronically provide artificial sensory input to all 3 implanted semicircular canals in individuals disabled by bilateral vestibular loss, driving reflexive VOR eye movements that approximately align in 3D with the head motion axis encoded by the implant.TRIAL REGISTRATION ClinicalTrials.gov: NCT02725463.FUNDING NIH/National Institute on Deafness and Other Communication Disorders: R01DC013536 and 2T32DC000023; Labyrinth Devices, LLC; and Med-El GmbH.

Authors

Peter J. Boutros, Desi P. Schoo, Mehdi Rahman, Nicolas S. Valentin, Margaret R. Chow, Andrianna I. Ayiotis, Brian J. Morris, Andreas Hofner, Aitor Morillo Rascon, Andreas Marx, Ross Deas, Gene Y. Fridman, Natan S. Davidovics, Bryan K. Ward, Carolina Treviño, Stephen P. Bowditch, Dale C. Roberts, Kelly E. Lane, Yoav Gimmon, Michael C. Schubert, John P. Carey, Andreas Jaeger, Charles C. Della Santina

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Abstract

Mammalian focal adhesion proteins Pinch1 and Pinch2 regulate integrin activation and cell–extracellular matrix adhesion and migration. Here, we show that deleting Pinch1 in osteocytes and mature osteoblasts using the 10-kb mouse Dmp1-Cre and Pinch2 globally (double KO; dKO) results in severe osteopenia throughout life, while ablating either gene does not cause bone loss, suggesting a functional redundancy of both factors in bone. Pinch deletion in osteocytes and mature osteoblasts generates signals that inhibit osteoblast and bone formation. Pinch-deficient osteocytes and conditioned media from dKO bone slice cultures contain abundant sclerostin protein and potently suppress osteoblast differentiation in primary BM stromal cells (BMSC) and calvarial cultures. Pinch deletion increases adiposity in the BM cavity. Primary dKO BMSC cultures display decreased osteoblastic but enhanced adipogenic, differentiation capacity. Pinch loss decreases expression of integrin β3, integrin-linked kinase (ILK), and α-parvin and increases that of active caspase-3 and -8 in osteocytes. Pinch loss increases osteocyte apoptosis in vitro and in bone. Pinch loss upregulates expression of both Rankl and Opg in the cortical bone and does not increase osteoclast formation and bone resorption. Finally, Pinch ablation exacerbates hindlimb unloading–induced bone loss and impairs active ulna loading–stimulated bone formation. Thus, we establish a critical role of Pinch in control of bone homeostasis.

Authors

Yishu Wang, Qinnan Yan, Yiran Zhao, Xin Liu, Simin Lin, Peijun Zhang, Liting Ma, Yumei Lai, Xiaochun Bai, Chuanju Liu, Chuanyue Wu, Jian Q. Feng, Di Chen, Huiling Cao, Guozhi Xiao

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Abstract

Broadly neutralizing Abs targeting the HA stem can provide broad protection against different influenza subtypes, raising the question of how best to elicit such Abs. We have previously demonstrated that vaccination with pandemic live-attenuated influenza vaccine (pLAIV) establishes immune memory for HA head-specific Abs. Here, we determine the extent to which matched versus mismatched LAIV-inactivated subunit vaccine (IIV) prime-boost vaccination elicits stem-specific memory B cells and Abs. We vaccinated African green monkeys with H5N1 pLAIV-pIIV or H5N1 pLAIV followed by seasonal IIV (sIIV) or with H5N1 pLAIV alone and measured Abs and HA-specific B cell responses. While we observed an increase in stem-specific memory B cells, head-specific memory B cell responses were substantially higher than stem-specific responses and were dominant even following boost with mismatched IIV. Neutralizing Abs against heterologous influenza viruses were undetectable. Head-specific B cells from draining lymph nodes exhibited germinal center markers, while stem-specific B cells found in the spleen and peripheral blood did not. Thus, although mismatched prime-boost generated a pool of stem-specific memory B cells, head-specific B cells and serum Abs substantially dominated the immune response. These findings have implications for including full-length native HA in prime-boost strategies intended to induce stem-specific Abs for universal influenza vaccination.

Authors

Sinthujan Jegaskanda, Sarah F. Andrews, Adam K. Wheatley, Jonathan W. Yewdell, Adrian B. McDermott, Kanta Subbarao

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Abstract

In addition to its well-known beneficial effects for the treatment of several types of cancer, PD-1 blockade has shown encouraging results in preclinical models of sepsis and in a recent clinical trial in sepsis. Because cancer is the most common comorbidity in septic patients, here we aimed to determine the efficacy of PD-1 checkpoint blockade in the setting of sepsis complicated with preexisting malignancy. In a model of established lung cancer followed by cecal ligation and puncture–induced (CLP-induced) sepsis, PD-1 blockade exhibited no therapeutic effect on sepsis survival. This diminished efficacy of PD-1 blockade in cancer septic animals (septic animals with cancer) was characterized by a reduction in both the quality and quantity of PD-1+ responder cells. Specifically, CD8+ T cells isolated from cancer septic animals exhibited decreased CD28 expression and a reduction in the CXCR5+PD-1+ subset. In addition, flow cytometric analysis of T cells isolated from cancer septic animals revealed 2B4 as another possible checkpoint under these conditions. Administration of anti-2B4 to cancer septic animals significantly improved sepsis survival and was associated with increased T cell costimulatory receptor expression and decreased coinhibitory receptor expression. These results illustrate functions of coinhibitory receptors in the setting of sepsis complicated with cancer.

Authors

Ching-wen Chen, Ming Xue, Wenxiao Zhang, Jianfeng Xie, Craig M. Coopersmith, Mandy L. Ford

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Abstract

Dysregulated citrullination, a unique form of posttranslational modification catalyzed by the peptidylarginine deiminases (PADs), has been observed in several human diseases, including rheumatoid arthritis. However, the physiological roles of PADs in the immune system are still poorly understood. Here, we report that global inhibition of citrullination enhances the differentiation of type 2 helper T (Th2) cells but attenuates the differentiation of Th17 cells, thereby increasing the susceptibility to allergic airway inflammation. This effect on Th cells is due to inhibition of PAD2 but not PAD4. Mechanistically, PAD2 directly citrullinates GATA3 and RORγt, 2 key transcription factors determining the fate of differentiating Th cells. Citrullination of R330 of GATA3 weakens its DNA binding ability, whereas citrullination of 4 arginine residues of RORγt strengthens its DNA binding. Finally, PAD2-deficient mice also display altered Th2/Th17 immune response and heightened sensitivity to allergic airway inflammation. Thus, our data highlight the potential and caveat of PAD2 as a therapeutic target of Th cell–mediated diseases.

Authors

Bo Sun, Hui-Hsin Chang, Ari Salinger, Beverly Tomita, Mandar Bawadekar, Caitlyn L. Holmes, Miriam A. Shelef, Eranthie Weerapana, Paul R. Thompson, I-Cheng Ho

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Abstract

The ciliopathies are a group of phenotypically overlapping disorders caused by structural or functional defects in the primary cilium. Although disruption of numerous signaling pathways and cellular trafficking events have been implicated in ciliary pathology, treatment options for affected individuals remain limited. Here, we performed a genome-wide RNAi (RNA interference) screen to identify genetic suppressors of BBS4, one of the genes mutated in Bardet-Biedl syndrome (BBS). We discovered 10 genes that, when silenced, ameliorate BBS4-dependent pathology. One of these encodes USP35, a negative regulator of the ubiquitin proteasome system, suggesting that inhibition of a deubiquitinase, and subsequent facilitation of the clearance of signaling components, might ameliorate BBS-relevant phenotypes. Testing of this hypothesis in transient and stable zebrafish genetic models showed this posit to be true; suppression or ablation of usp35 ameliorated hallmark ciliopathy defects including impaired convergent extension (CE), renal tubule convolution, and retinal degeneration with concomitant clearance of effectors such as β-catenin and rhodopsin. Together, our findings reinforce a direct link between proteasome-dependent degradation and ciliopathies and suggest that augmentation of this system might offer a rational path to novel therapeutic modalities.

Authors

I-Chun Tsai, Kevin A. Adams, Joyce A. Tzeng, Omar Shennib, Perciliz L. Tan, Nicholas Katsanis

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Abstract

Aging is a major risk factor for cardiovascular disease. Although the impact of aging has been extensively studied, little is known regarding the aging processes in cells of the heart. Here we analyzed the transcriptomes of hearts of 12-week-old and 18-month-old mice by single-nucleus RNA-sequencing. Among all cell types, aged fibroblasts showed most significant differential gene expression, increased RNA dynamics, and network entropy. Aged fibroblasts exhibited significantly changed expression patterns of inflammatory, extracellular matrix organization angiogenesis, and osteogenic genes. Functional analyses indicated deterioration of paracrine signatures between fibroblasts and endothelial cells in old hearts. Aged heart-derived fibroblasts had impaired endothelial cell angiogenesis and autophagy and augmented proinflammatory response. In particular, expression of Serpine1 and Serpine2 were significantly increased and secreted by old fibroblasts to exert antiangiogenic effects on endothelial cells, an effect that could be significantly prevented by using neutralizing antibodies. Moreover, we found an enlarged subpopulation of aged fibroblasts expressing osteoblast genes in the epicardial layer associated with increased calcification. Taken together this study provides system-wide insights and identifies molecular changes of aging cardiac fibroblasts, which may contribute to declined heart function.

Authors

Ramon Vidal, Julian Uwe Gabriel Wagner, Caroline Braeuning, Cornelius Fischer, Ralph Patrick, Lukas Tombor, Marion Muhly-Reinholz, David John, Magdalena Kliem, Thomas Conrad, Nuno Guimarães-Camboa, Richard Harvey, Stefanie Dimmeler, Sascha Sauer

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Abstract

Background: Hepatic encephalopathy (HE) is associated with poor outcomes. A prior randomized, pilot trial demonstrated safety after oral capsular FMT in HE with favorable changes in microbial composition and cognition. However, microbial functional changes are unclear. Aim: Determine impact of FMT on gut-brain axis compared to placebo using microbial function based on bile acids (BA), inflammation (serum IL-6, lipopolysaccharide-binding protein,LBP), and EncephalApp. Methods: 20 cirrhotic patients were randomized 1:1 into receiving one-time FMT capsules from a donor enriched in Lachnospiraceae and Ruminococcaceae, or placebo capsules with 5-month follow-up for safety outcomes. Stool microbiota and BA, serum IL-6, BA and LBP, and EncephalApp were analyzed at baseline and 4-weeks post-FMT/placebo. Correlation networks between microbiota, BAs, EncephalApp, IL-6 and LBP were performed pre/post-FMT. Results: FMT-assigned participants had one HE recurrence and 2 unrelated infections. Six placebo-assigned participants developed negative outcomes. FMT, but not placebo, was associated with reduced serum IL-6 and LBP and improved EncephalApp. FMT-assigned participants demonstrated higher deconjugation and secondary BA formation in feces and serum compared to baseline. No change was seen in placebo. Correlation networks showed greater complexity post-FMT compared to baseline. Beneficial taxa such as Ruminococcaceae, Verrucomicrobiaceae and Lachnospiraceae were correlated with cognitive improvement and decrease in inflammation post-FMT. Fecal/serum secondary/primary ratios and PiCRUST secondary BA pathways did not increase in participants who developed poor outcomes. Conclusions: Gut microbial function in cirrhosis is beneficially affected by capsular FMT with improved inflammation and cognition. Lower secondary BAs in FMT recipients could select for participants who develop negative outcomes.

Authors

Jasmohan S. Bajaj, Nita Salzman, Chathur Acharya, Hajime Takei, Genta Kakiyama, Andrew Fagan, Melanie B. White, Edith A. Gavis, Mary L. Holtz, Michael Hayward, Hiroshi Nittono, Philip B. Hylemon, I. Jane Cox, Roger Williams, Simon D. Taylor-Robinson, Richard K. Sterling, Scott C. Matherly, Michael Fuchs, Hannah Lee, Puneet Puri, R. Todd Stravitz, Arun J. Sanyal, Lola Ajayi, Adrien Le Guennec, R. Andrew Atkinson, Mohammad S. Siddiqui, Velimir A. Luketic, William M. Pandak, Masoumeh Sikaroodi, Patrick M. Gillevet

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Abstract

As sufficient extracellular arginine is crucial for T cell function, depletion of extracellular arginine by elevated Arginase 1 (Arg1) activity has emerged as a hallmark immunosuppressive mechanism. However, the potential cell-autonomous roles of arginases in T cells have remained unexplored. Here we show that the arginase isoform expressed by T cells, the mitochondrial Arginase 2 (Arg2), is a cell-intrinsic regulator of CD8+ T cell activity. Both germ-line Arg2 deletion and adoptive transfer of Arg2-/- CD8+ T cells significantly reduced tumor growth in preclinical cancer models by enhancing CD8+ T cell activation, effector function and persistence. Transcriptomic, proteomic and high-dimensional flow cytometry characterization revealed a CD8+ T cell-intrinsic role of Arg2 in modulating T cell activation, anti-tumor cytoxicity and memory formation, independently of extracellular arginine availability. Furthermore, specific deletion of Arg2 in CD8+ T cells strongly synergized with PD-1 blockade for the control of tumor growth and animal survival. These observations coupled with the finding that pharmacologic arginase inhibition accelerates activation of ex vivo human T cells unveil Arg2 as a new therapeutic target for T cell-based cancer therapies.

Authors

Adrià-Arnau Martí i Líndez, Isabelle Dunand-Sauthier, Mark Conti, Florian Gobet, Nicolás Núñez, J. Thomas Hannich, Howard Riezman, Geiger Roger, Alessandra Piersigilli, Kerstin Hahn, Sylvain Lemeille, Burkhard Becher, Thibaut De Smedt, Stéphanie Hugues, Walter Reith

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Abstract

Proteinuric chronic kidney disease (CKD) remains a major health problem worldwide. While the progression of primary glomerular disease to induce tubulointerstitial lesions is well established, the effect of tubular injury to trigger glomerular damage is poorly understood. We hypothesized that injured tubules secrete mediators that adversely affect glomerular health. To test this, we utilized conditional knockout mice with tubule-specific ablation of β-catenin (Ksp-β-cat-/-), and subjected them to chronic angiotensin II (Ang II) infusion or adriamycin. Compared to control mice, Ksp-β-cat-/- mice were dramatically protected from proteinuria and glomerular damage. Matrix metalloproteinase-7 (MMP-7), a downstream target of β-catenin, was upregulated in treated control mice, but this induction was blunted in the Ksp-β-cat-/- littermates. Incubation of isolated glomeruli with MMP-7 ex vivo led to nephrin depletion and impaired glomerular permeability. Furthermore, MMP-7 specifically and directly degraded nephrin in cultured glomeruli or cell-free systems, and this effect was dependent on its proteolytic activity. In vivo, expression or infusion of exogenous MMP-7 caused proteinuria, and genetic ablation of MMP-7 protected mice from Ang II-induced proteinuria and glomerular injury. Collectively, these results demonstrate that beta-catenin-driven MMP-7 release from renal tubules promotes glomerular injury via direct degradation of the key slit diaphragm protein nephrin.

Authors

Roderick J. Tan, Yingjian Li, Brittney M. Rush, Débora Malta Cerqueira, Dong Zhou, Haiyan Fu, Jacqueline Ho, Donna Beer Stolz, Youhua Liu

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Abstract

Background: Bacille Calmette-Guérin (BCG) vaccine is protective in children but its efficacy wanes with age. Consequently, determining if BCG revaccination augments anti-TB immunity in young adults in TB endemic regions is vital. Methods: 200 healthy adults, BCG vaccinated at birth were tested for their IGRA status. Of these, 28 IGRA+ and 30 IGRA- were BCG revaccinated and 24 IGRA+ and 23 IGRA- subjects served as unvaccinated controls. T and innate cell responses to mycobacterial antigens were analyzed by 14-colour flow cytometry over 34 weeks. Results: IFN-γ and/or IL-2 Ag85A and BCG-specific CD4+ and CD8+ T-cell responses were boosted by revacciantion at 4 and 34 weeks respectively and were >2-fold higher in IGRA+ compared to IGRA- vaccinees. Polyfunctional Ag85A, BCG and Mtb latency Ag (LTAg)-specific CD4+ T-cells expressing up to 8 cytokines were also significantly enhanced in both IGRA+ and IGRA- vaccinees relative to unvaccinated controls, most markedly in IGRA+ vaccinees. A focussed analysis of Th17 responses revealed expansion of Ag85A, BCG and LTAg-specific total IL-17A+IL-17F+IL-22+ and IL-10+ CD4+ T-cell effectors in both IGRA+ and IGRA- subjects. Also, innate IFN-γ+ NK/γδ/NKT responses were higher in both IGRA+ and IGRA- vaccinees compared to controls. This is the first evidence that BCG revaccination significantly boosts anti-mycobacterial Th1/Th17 responses in IGRA+ and IGRA- subjects. Summary: These data show that BCG revaccination is immunogenic in IGRA- and IGRA+ subjects implying that Mtb pre-infection in IGRA+ subjects does not impact immunogenicity. This has implications for public health and vaccine development strategies. Funding: This work was funded principally by DBT-NIH (BT/MB/Indo-US/HIPC/2013).

Authors

Srabanti Rakshit, Asma Ahmed, Vasista Adiga, Bharath K. Sundararaj, Pravat Nalini Sahoo, John Kenneth, George D'Souza, Wesley Bonam, Christina Johnson, Kees L.M.C. Franken, Tom H.M. Ottenhoff, Greg Finak, Raphael Gottardo, Kenneth D. Stuart, Stephen C. De Rosa, M. Juliana McElrath, Annapurna Vyakarnam

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Abstract

Introduction: The airways of obese asthmatics have been shown to be nitric oxide (NO) deficient, which contributes to airway dysfunction and reduced response to inhaled corticosteroids (ICS). In cultured airway epithelial cells, L-citrulline, a precursor of L-arginine recycling and NO formation, has been shown to prevent asymmetric di-methyl arginine (ADMA)-mediated NO synthase (NOS2) uncoupling, restoring NO and reducing oxidative stress. Methods: In a proof of concept, pre – post open label pilot study, we hypothesized that 15g/day of L-citrulline for two weeks would: a) increase the fractional excretion of NO (FeNO); b) improve asthma control and c) improve lung function. To do this, we recruited obese (body mass index [BMI] >30) asthmatics on controller therapy with a baseline fractional exhaled nitric oxide (FeNO) ≤ 30 ppb from the University of Colorado Medical Center and Duke University Health System. Results: A total of 41 subjects with an average FeNO of 17 ppb (95% 19 - 20) and poorly controlled asthma (average asthma control questionnaire [ACQ] 1.5 [95% 1.2 – 1.8) completed the study. Compared to baseline, L-citrulline increased (values represent the mean delta and 95%CI): plasma L-citrulline (190uM, 84 – 297), plasma L-arginine (67uM, 38 – 95), plasma L-arginine/ADMA (117, 67 - 167), but not ADMA or arginase concentration. FeNO increased by 4.2ppb (1.7 – 6.7); ACQ decreased by -0.46 (-0.67 – -0.27); the forced vital capacity (FVC) and forced exhalation volume in one second (FEV1) respectively changed by 86 ml (10 – 161), and 52 ml (-11 – 132). In a secondary analysis, the greatest FEV1 increments occurred in those subjects with late onset asthma (>12 years) (63 ml [95%CI 1 – 137]), in females (80 ml [95%CI 5 – 154]), with a greater change seen in late onset females (100ml, [95%CI 2 – 177]). The changes in lung function or asthma control were not significantly associated with the pre-post changes in L-arginine/ADMA or FeNO. Conclusion: Short-term L-citrulline treatment improved asthma control and FeNO levels in obese asthmatics with low or normal FeNO. Larger FEV1 increments were observed in those with late onset asthma and in females.

Authors

Fernando Holguin, Hartmut Grasemann, Sunita Sharma, Daniel Winnica, Karen Wasil, Vong Smithphone, Margaret H. Cruse, Nancy Perez, Erika Coleman, Timothy J. Scialla, Loretta Que

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