Mitochondrial fusion exploits a therapeutic vulnerability of pancreatic cancer
In this issue, Yu et al. show in pancreatic cancer cells that promoting mitochondrial fusion, via inhibition of dynamin related protein-1 or overexpression of mitofusin-2, normalizes fragmented mitochondria, which alters tumor metabolism and correlates with suppressed tumor growth and improved survival in preclinical models. The cover image is a false colored transmission electron micrograph showing mitochondrial morphology (purple spheres) in pancreatic cancer cells.
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Research Articles
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Abstract
Abnormalities in purine availability or purinergic receptor density are commonly seen in patients with lower urinary tract symptoms (LUTS), but the underlying mechanisms relating altered receptor function to LUTS are unknown. Here we provide extensive evidence for the reciprocal interplay of multiple receptors responding to ATP, ADP (adenosine diphosphate), and adenosine, agonists that regulate bladder function significantly. ADP stimulated P2Y12 receptors, causing bladder smooth muscle (BSM) contraction, whereas adenosine signaling through potentially newly defined A2b receptors, actively inhibited BSM purinergic contractility. The modulation of adenylyl cyclase-cAMP signaling via A2b and P2Y12 interaction actively regulated bladder contractility by modulating intracellular calcium levels. KO mice lacking the receptors display diametrically opposed bladder phenotypes, with P2Y12-KO mice exhibiting an underactive bladder (UAB) phenotype with increased bladder capacity and reduced voiding frequency, whereas A2b-KO mice have an overactive bladder (OAB), with decreased capacity and increased voiding frequency. The opposing phenotypes in P2Y12-KO and A2b-KO mice not only resulted from dysregulated BSM contractility, but also from abnormal BSM cell growth. Finally, we demonstrate that i.p. administration of drugs targeting P2Y12 or A2b receptor rescues these abnormal phenotypes in both KO mice. These findings strongly indicate that P2Y12 and A2b receptors are attractive therapeutic targets for human patients with LUTS.
Authors
Yuan Hao, Lu Wang, Huan Chen, Warren G. Hill, Simon C. Robson, Mark L. Zeidel, Weiqun Yu
×Abstract
Tissue remodeling/fibrosis is a major feature of all fibrotic diseases, including idiopathic pulmonary fibrosis (IPF). It is underpinned by accumulating extracellular matrix (ECM) proteins. Fibulin-1c (Fbln1c) is a matricellular ECM protein associated with lung fibrosis in both humans and mice and stabilizes collagen formation. Here we discovered that Fbln1c was increased in the lung tissues of patients with IPF and experimental bleomycin-induced pulmonary fibrosis. Fbln1c-deficient (Fbln1c–/–) mice had reduced pulmonary remodeling/fibrosis and improved lung function after bleomycin challenge. Fbln1c interacted with fibronectin, periostin, and tenascin-C in collagen deposits following bleomycin challenge. In a potentially novel mechanism of fibrosis, Fbln1c bound to latent TGF-β–binding protein 1 (LTBP1) to induce TGF-β activation and mediated downstream Smad3 phosphorylation/signaling. This process increased myofibroblast numbers and collagen deposition. Fbln1c and LTBP1 colocalized in lung tissues from patients with IPF. Thus, Fbln1c may be a novel driver of TGF-β–induced fibrosis involving LTBP1 and may be an upstream therapeutic target.
Authors
Gang Liu, Marion A. Cooley, Andrew G. Jarnicki, Theo Borghuis, Prema M. Nair, Gavin Tjin, Alan C. Hsu, Tatt Jhong Haw, Michael Fricker, Celeste L. Harrison, Bernadette Jones, Nicole G. Hansbro, Peter A. Wark, Jay C. Horvat, W. Scott Argraves, Brian G. Oliver, Darryl A. Knight, Janette K. Burgess, Philip M. Hansbro
×Abstract
Although mucoactive proteins, such as epidermal growth factor (EGF), could improve clinical outcomes of intestinal ulcerative diseases, their gastrointestinal application is limited because of their proteolytic digestion or concerns about tumor promotion. In the present study, ATP-binding cassette (ABC) transporter–linked secretion of human EGF from probiotic Escherichia coli (EGF-EcN) was created to promote beneficial actions of the EGF receptor, which is notably attenuated in patients with intestinal ulcerative injuries. Preventive and postinjury treatment with EGF-EcN alleviated intestinal ulcers and other readouts of disease severity in murine intestinal ulcer models. EGF-EcN administration promoted the restitutive recovery of damaged epithelial layers, particularly via upward expansion of highly proliferating progenitor cells from the lower crypts. Along with the epithelial barrier benefit, EGF-EcN improved goblet cell–associated mucosal integrity, which controls the access of luminal microbiota to the underlying host tissues. Despite concern about the oncogenic action of EGF, EGF-EcN did not aggravate colitis-associated colon cancer; instead, it alleviated protumorigenic activities and improved barrier integrity in the lesions. All findings indicate that probiotic bacteria–based precision delivery of human EGF is a promising mucosal intervention against gastrointestinal ulcers and malignant distress through crypt-derived barrier restoration.
Authors
Mira Yu, Juil Kim, Jung Hoon Ahn, Yuseok Moon
×Abstract
Mesenchymal stem cells (MSCs) can suppress pathological inflammation. However, the mechanisms underlying the association between MSCs and inflammation remain unclear. Under coculture conditions with macrophages, MSCs highly expressed angiopoietin-like 4 (ANGPTL4) to blunt the polarization of macrophages toward the proinflammatory phenotype. ANGPTL4-deficient MSCs failed to inhibit the inflammatory macrophage phenotype. In inflammation-related animal models, the injection of coculture medium or ANGPTL4 protein increased the antiinflammatory macrophages in both peritonitis and myocardial infarction. In particular, cardiac function and pathology were markedly improved by ANGPTL4 treatment. We found that retinoic acid–related orphan receptor α (RORα) was increased by inflammatory mediators, such as IL-1β, and bound to ANGPTL4 promoter in MSCs. Collectively, RORα-mediated ANGPTL4 induction was shown to contribute to the antiinflammatory activity of MSCs against macrophages under pathological conditions. This study suggests that the capability of ANGPTL4 to induce tissue repair is a promising opportunity for safe stem cell–free regeneration therapy from a translational perspective.
Authors
Dong Im Cho, Hye-jin Kang, Ju Hee Jeon, Gwang Hyeon Eom, Hyang Hee Cho, Mi Ra Kim, Meeyoung Cho, Hye-yun Jeong, Hyen Chung Cho, Moon Hwa Hong, Yong Sook Kim, Youngkeun Ahn
×Abstract
Left ventricular noncompaction (LVNC) is one of the most common forms of genetic cardiomyopathy characterized by excessive trabeculation and impaired myocardial compaction during fetal development. Patients with LVNC are at higher risk of developing left/right ventricular failure or both. Although the key regulators for cardiac chamber development are well studied, the role of semaphorin (Sema)/plexin signaling in this process remains poorly understood. In this article, we demonstrate that genetic deletion of Plxnd1, a class-3 Sema receptor in endothelial cells, leads to severe cardiac chamber defects. They were characterized by excessive trabeculation and noncompaction similar to patients with LVNC. Loss of Plxnd1 results in decreased expression of extracellular matrix proteolytic genes, leading to excessive deposition of cardiac jelly. We demonstrate that Plxnd1 deficiency is associated with an increase in Notch1 expression and its downstream target genes. In addition, inhibition of the Notch signaling pathway partially rescues the excessive trabeculation and noncompaction phenotype present in Plxnd1 mutants. Furthermore, we demonstrate that Semaphorin 3E (Sema3E), one of PlexinD1’s known ligands, is expressed in the developing heart and is required for myocardial compaction. Collectively, our study uncovers what we believe to be a previously undescribed role of the Sema3E/PlexinD1 signaling pathway in myocardial trabeculation and the compaction process.
Authors
Reddemma Sandireddy, Dasan Mary Cibi, Priyanka Gupta, Anamika Singh, Nicole Tee, Akiyoshi Uemura, Jonathan A. Epstein, Manvendra K. Singh
×Abstract
Chronic inflammation causes target organ damage in patients with systemic autoimmune diseases. The factors that allow this protracted response are poorly understood. We analyzed the transcriptional regulation of PPP2R2B (B55β), a molecule necessary for the termination of the immune response, in patients with autoimmune diseases. Altered expression of B55β conditioned resistance to cytokine withdrawal–induced death (CWID) in patients with autoimmune diseases. The impaired upregulation of B55β was caused by inflammation-driven hypermethylation of specific cytosines located within a regulatory element of PPP2R2B preventing CCCTC-binding factor binding. This phenotype could be induced in healthy T cells by exposure to TNF-α. Our results reveal a gene whose expression is affected by an acquired defect, through an epigenetic mechanism, in the setting of systemic autoimmunity. Because failure to remove activated T cells through CWID could contribute to autoimmune pathology, this mechanism illustrates a vicious cycle through which autoimmune inflammation contributes to its own perpetuation.
Authors
Iris K. Madera-Salcedo, Beatriz E. Sánchez-Hernández, Yevgeniya Svyryd, Marcela Esquivel-Velázquez, Noé Rodríguez-Rodríguez, María Isabel Trejo-Zambrano, H. Benjamín García-González, Gabriela Hernández-Molina, Osvaldo M. Mutchinick, Jorge Alcocer-Varela, Florencia Rosetti, José C. Crispín
×Abstract
Macrophage activation is implicated in the development of pulmonary fibrosis by generation of profibrotic molecules. Although NADPH oxidase 4 (NOX4) is known to contribute to pulmonary fibrosis, its effects on macrophage activation and mitochondrial redox signaling are unclear. Here, we show that NOX4 is crucial for lung macrophage profibrotic polarization and fibrotic repair after asbestos exposure. NOX4 was elevated in lung macrophages from subjects with asbestosis, and mice harboring a deletion of NOX4 in lung macrophages were protected from asbestos-induced fibrosis. NOX4 promoted lung macrophage profibrotic polarization and increased production of profibrotic molecules that induce collagen deposition. Mechanistically, NOX4 further augmented mitochondrial ROS production and induced mitochondrial biogenesis. Targeting redox signaling and mitochondrial biogenesis prevented the profibrotic polarization of lung macrophages by reducing the production of profibrotic molecules. These observations provide evidence that macrophage NOX4 is a potentially novel therapeutic target to halt the development of asbestos-induced pulmonary fibrosis.
Authors
Chao He, Jennifer L. Larson-Casey, Dana Davis, Vidya Sagar Hanumanthu, Ana Leda F. Longhini, Victor J. Thannickal, Linlin Gu, A. Brent Carter
×Abstract
Pancreatic ductal adenocarcinoma (PDAC) requires mitochondrial oxidative phosphorylation (OXPHOS) to fuel its growth; however, broadly inhibiting this pathway might also disrupt essential mitochondrial functions in normal tissues. PDAC cells exhibit abnormally fragmented mitochondria that are essential to the oncogenicity of PDAC, but it was unclear if this mitochondrial feature was a valid therapeutic target. Here, we present evidence that normalizing the fragmented mitochondria of pancreatic cancer via the process of mitochondrial fusion reduces OXPHOS, which correlates with suppressed tumor growth and improved survival in preclinical models. Mitochondrial fusion was achieved by genetic or pharmacologic inhibition of dynamin-related protein-1 (Drp1) or through overexpression of mitofusin-2 (Mfn2). Notably, we found that oral leflunomide, an FDA-approved arthritis drug, promoted a 2-fold increase in Mfn2 expression in tumors and was repurposed as a chemotherapeutic agent, improving the median survival of mice with spontaneous tumors by 50% compared with vehicle. We found that the chief tumor-suppressive mechanism of mitochondrial fusion was enhanced mitophagy, which proportionally reduced mitochondrial mass and ATP production. These data suggest that mitochondrial fusion is a specific and druggable regulator of pancreatic cancer growth that could be rapidly translated to the clinic.
Authors
Meifang Yu, Nicholas D. Nguyen, Yanqing Huang, Daniel Lin, Tara N. Fujimoto, Jessica M. Molkentine, Amit Deorukhkar, Ya’an Kang, F. Anthony San Lucas, Conrad J. Fernandes, Eugene J. Koay, Sonal Gupta, Haoqiang Ying, Albert C. Koong, Joseph M. Herman, Jason B. Fleming, Anirban Maitra, Cullen M. Taniguchi
×Abstract
The complex process of platelet formation originates with the hematopoietic stem cell, which differentiates through the myeloid lineage, matures, and releases proplatelets into the BM sinusoids. How formed platelets maintain a low basal activation state in the circulation remains unknown. We identify Lepr+ stromal cells lining the BM sinusoids as important contributors to sustaining low platelet activation. Ablation of murine Lepr+ cells led to a decreased number of platelets in the circulation with an increased activation state. We developed a potentially novel culture system for supporting platelet formation in vitro using a unique population of CD51+PDGFRα+ perivascular cells, derived from human umbilical cord tissue, which display numerous mesenchymal stem cell (MSC) properties. Megakaryocytes cocultured with MSCs had altered LAT and Rap1b gene expression, yielding platelets that are functional with low basal activation levels, a critical consideration for developing a transfusion product. Identification of a regulatory cell that maintains low baseline platelet activation during thrombopoiesis opens up new avenues for improving blood product production ex vivo.
Authors
Avital Mendelson, Ana Nicolle Strat, Weili Bao, Peter Rosston, Georgia Fallon, Sophie Ohrn, Hui Zhong, Cheryl Lobo, Xiuli An, Karina Yazdanbakhsh
×Abstract
Adoptive T cell therapy (ACT) has been established as an efficacious methodology for the treatment of cancer. Identifying targets to enhance the antigen recognition, functional capacity, and longevity of T cells has the potential to broaden the applicability of these approaches in the clinic. We previously reported that targeting expression of phosphotyrosine phosphatase, nonreceptor type 22 (PTPN22) in effector CD8+ T cells enhances the efficacy of ACT for tumor clearance in mice. In the current work, we demonstrate that, upon ACT, PTPN22-deficient effector CD8+ T cells afforded greater protection against tumors expressing very low-affinity antigen but did not survive long term in vivo. Persistence of CD8+ T cells following tumor clearance was improved by ACT of memory phenotype cells that have a distinct metabolic phenotype, as compared with effector T cells. Importantly, PTPN22-deficient T cells have comparable capacity to form long-lived memory cells in vivo but enhanced antitumor activity in vivo and effector responses ex vivo. These findings provide key insights into the regulation of effector and memory T cell responses in vivo and indicate that PTPN22 is a rational target to improve ACT for cancer.
Authors
Rebecca J. Brownlie, David Wright, Rose Zamoyska, Robert J. Salmond
×Abstract
The common patatin-like phospholipase domain–containing protein 3 (PNPLA3) variant I148M predisposes to nonalcoholic liver disease but not its metabolic sequelae. We compared the handling of labeled polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFA) in vivo in humans and in cells harboring different PNPLA3 genotypes. In 148M homozygous individuals, triglycerides (TGs) in very low–density lipoproteins (VLDL) were depleted of PUFAs both under fasting and postprandial conditions compared with 148I homozygotes, and the PUFA/SFA ratio in VLDL-TGs was lower relative to the chylomicron precursor pool. In human PNPLA3-148M and PNPLA3-KO cells, PUFA but not SFA incorporation into TGs was increased at the expense of phosphatidylcholines, and under lipolytic conditions, PUFA-containing diacylglycerols (DAGs) accumulated compared with PNPLA3-148I cells. Polyunsaturated TGs were increased, while phosphatidylcholines (PCs) were decreased in the human liver in 148M homozygous individuals as compared with 148I homozygotes. We conclude that human PNPLA3-I148M is a loss-of-function allele that remodels liver TGs in a polyunsaturated direction by impairing hydrolysis/transacylation of PUFAs from DAGs to feed phosphatidylcholine synthesis.
Authors
Panu K. Luukkonen, Auli Nick, Maarit Hölttä-Vuori, Christoph Thiele, Elina Isokuortti, Susanna Lallukka-Brück, You Zhou, Antti Hakkarainen, Nina Lundbom, Markku Peltonen, Marju Orho-Melander, Matej Orešič, Tuulia Hyötyläinen, Leanne Hodson, Elina Ikonen, Hannele Yki-Järvinen
×Abstract
Multiple organ failure (MOF) is the leading cause of late mortality and morbidity in patients who are admitted to intensive care units (ICUs). However, there is an epidemiologic discrepancy in the mechanism of underlying immunologic derangement dependent on etiology between sepsis and trauma patients in MOF. We hypothesized that damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), while both involved in the development of MOF, contribute differently to the systemic innate immune derangement and coagulopathic changes. We found that DAMPs not only produce weaker innate immune activation than counterpart PAMPs, but also induce less TLR signal desensitization, contribute to less innate immune cell death, and propagate more robust systemic coagulopathic effects than PAMPs. This differential contribution to MOF provides further insight into the contributing factors to late mortality in critically ill trauma and sepsis patients. These findings will help to better prognosticate patients at risk of MOF and may provide future therapeutic molecular targets in this disease process.
Authors
John Eppensteiner, Jean Kwun, Uwe Scheuermann, Andrew Barbas, Alexander T. Limkakeng, Maggie Kuchibhatla, Eric A. Elster, Allan D. Kirk, Jaewoo Lee
×Abstract
Targeting the dynamic tumor immune microenvironment (TIME) can provide effective therapeutic strategies for cancer. Neutrophils are the predominant leukocyte population in mice and humans, and mounting evidence implicates these cells during tumor growth and metastasis. Neutrophil extracellular traps (NETs) are networks of extracellular neutrophil DNA fibers that are capable of binding tumor cells to support metastatic progression. Here, we demonstrate that circulating NET levels are elevated in advanced esophageal, gastric, and lung cancer patients compared with local cancers and healthy controls. Using preclinical murine models of lung and colon cancer, in combination with intravital video microscopy, we show that NETs functionally regulate disease progression and that blocking NETosis through multiple strategies significantly inhibits spontaneous metastasis to the lung and liver. Furthermore, we show how inhibiting tumor-induced NETs decreases cancer cell adhesion to liver sinusoids following intrasplenic injection — a mechanism previously thought to be driven primarily by exogenous stimuli. Thus, in addition to neutrophil abundance, the functional contribution of NETosis within the TIME has critical translational relevance and represents a promising target to impede metastatic dissemination.
Authors
Roni F. Rayes, Jack G. Mouhanna, Ioana Nicolau, France Bourdeau, Betty Giannias, Simon Rousseau, Daniela Quail, Logan Walsh, Veena Sangwan, Nicholas Bertos, Jonathan Cools-Lartigue, Lorenzo E. Ferri, Jonathan D. Spicer
×Abstract
T follicular regulatory (TFR) cells are found in the germinal center (GC) response and help shape the antibody (Ab) response. However, the precise role of TFR cells in the GC is controversial. Here, we addressed TFR cell function using mice with impaired TFR cell development (Bcl6-flox/Foxp3-cre, or Bcl6FC mice), mice with augmented TFR cell development (Blimp1-flox/Foxp3-cre, or Blimp1FC mice), and two different methods of immunization. Unexpectedly, GC B cell levels positively correlated with TFR cell levels. Using a gene profiling approach, we found that TFH cells from TFR-deficient mice showed strong upregulation of granzyme B (Gzmb) and other effector CD8+ T cell genes, many of which were Stat4 dependent. The upregulation of cytotoxic genes was the highest in TFH cells from TFR-deficient mice where Blimp1 was also deleted in Foxp3+ regulatory T cells (Bcl6-flox/Prdm1-flox/Foxp3-cre [DKO] mice). Granzyme B– and Eomesodermin-expressing TFH cells correlated with a higher rate of apoptotic GC B cells. Klrg1+ TFH cells from DKO mice expressed higher levels of Gzmb. Our data show that TFR cells repress the development of abnormal cytotoxic TFH cells, and the presence of cytotoxic TFH cells correlates with a lower GC and Ab response. Our data show what we believe is a novel mechanism of action for TFR cells helping the GC response.
Authors
Markus M. Xie, Shuyi Fang, Qiang Chen, Hong Liu, Jun Wan, Alexander L. Dent
×Abstract
Pancreatic ductal adenocarcinoma (PDA) is a major cause of cancer-related death, with limited therapeutic options available. This highlights the need for improved understanding of the biology of PDA progression, a highly complex and dynamic process, featuring changes in cancer cells and stromal cells. A comprehensive characterization of PDA cancer cell and stromal cell heterogeneity during disease progression is lacking. In this study, we aimed to profile cell populations and understand their phenotypic changes during PDA progression. To that end, we used single-cell RNA–sequencing technology to agnostically profile cell heterogeneity during different stages of PDA progression in genetically engineered mouse models. Our data indicate that an epithelial-mesenchymal transition of cancer cells accompanies tumor progression in addition to distinct populations of macrophages with increasing inflammatory features. We also noted the existence of 3 distinct molecular subtypes of fibroblasts in the normal mouse pancreas, which ultimately gave rise to 2 distinct populations of fibroblasts in advanced PDA, supporting recent reports on intratumor fibroblast heterogeneity. Our data also suggest that cancer cells and fibroblasts may be dynamically regulated by epigenetic mechanisms. This study systematically describes the landscape of cellular heterogeneity during the progression of PDA and has the potential to act as a resource in the development of therapeutic strategies against specific cell populations of the disease.
Authors
Abdel Nasser Hosein, Huocong Huang, Zhaoning Wang, Kamalpreet Parmar, Wenting Du, Jonathan Huang, Anirban Maitra, Eric Olson, Udit Verma, Rolf A. Brekken
×Abstract
Human islet isolation is a cost- and resource-intensive program for generating islets for cell therapy in type 1 diabetes. However, only one-third of cadaveric pancreases get to clinical transplantation because of low quality/number of islets. There is a need to identify biomarkers that predict the quality of islets, before initiating their isolation. Here, we sequenced transcriptomes from 18 human islet preparations stratified into 3 groups (group 1: best quality/transplantable islets; group 2: intermediary quality; and group 3: inferior quality/nontransplantable islets) based on routine measurements, including islet purity/viability. Machine-learning algorithms involving penalized regression analyses identified 10 long noncoding RNAs (lncRNAs) that were significantly different across all group-wise comparisons (group 1 vs. group 2, group 2 vs. group 3, and group 1 vs. group 3). Two variants of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) lncRNA were common across all comparisons. We then confirmed RNA-Seq findings in a validation set of 75 human islet preparations. Finally, in 19 pancreas samples, we demonstrated that assessing the levels of MALAT1 variants alone (receiver operator characteristic curve AUC: 0.83) offers higher specificity in predicting postisolation islet quality, further improving the predictive potential for clinical islet transplantation when combined with Edmonton Donor Points/BMI/North American Islet Donor Score. We present this resource of islet quality–stratified lncRNA transcriptome data and identify MALAT1 as a biomarker that significantly enhances current selection methods for clinical-grade (good manufacturing practice–grade) islet isolation.
Authors
Wilson K.M. Wong, Guozhi Jiang, Anja E. Sørensen, Yi Vee Chew, Cody Lee-Maynard, David Liuwantara, Lindy Williams, Philip J. O’Connell, Louise T. Dalgaard, Ronald C. Ma, Wayne J. Hawthorne, Mugdha V. Joglekar, Anandwardhan A. Hardikar
×Abstract
BACKGROUND Acute graft versus host disease (aGvHD) is a major factor that limits the successful outcomes of allogeneic hematopoietic cell transplantation (alloHSCT). Currently, there are few validated biomarkers that can help predict the risk of aGvHD in clinical settings.METHODS We performed an integrated metabolomics and transcriptomics study and identified biomarkers that distinguish alloHSCT recipients with aGvHD from alloHSCT recipients without aGvHD in 2 separate cohorts.RESULTS Pathway analysis of 38 significantly altered metabolites and 1,148 differentially expressed genes uncovered a distinctly altered glycerophospholipid (GPL) metabolism network. Subsequently, we developed an aGvHD risk score (GRS) based on 5 metabolite markers from GPL metabolism to predict the risk of aGvHD. GRS showed a positive predictive value of 92.2% and 89.6% in the training and validation cohorts, respectively. In addition, high GRS was correlated with poor overall survival. Gene expressions of GPL-related lipases were significantly altered in aGvHD samples, leading to dysregulated GPLs.CONCLUSION Using integrative “Omic” analysis, we unraveled a comprehensive view of the molecular perturbations underlying the pathogenesis of aGvHD. Our work represents an initial investigation of a unique metabolic and transcriptomic network that may help identify aGvHD at an early stage and facilitate preemptive therapy.FUNDING National Natural Science Foundation of China (NSFC; 81530047, 81870143, 81470321, 81770160, 81270567, 81270638, 81573396, 81703674) provided funding for material, processing, metabolomics, and transcriptomics studies. This work was also supported by Shanghai Sailing Program from Science and Technology Commission Shanghai Municipality (17YF1424700), the Scholarship from Shanghai Municipal Health and Family Planning Commission (2017BR012), and the Special Clinical Research in Health Industry in Shanghai (20184Y0054). The projects supporting young scholars are 17YF1424700 (to YL), 2017BR012 (to XH), and 20184Y0054 (to QC).
Authors
Yue Liu, Aijie Huang, Qi Chen, Xiaofei Chen, Yang Fei, Xiaoming Zhao, Weiping Zhang, Zhanying Hong, Zhenyu Zhu, Jianmin Yang, Yifeng Chai, Jianmin Wang, Xiaoxia Hu
×Abstract
The synucleinopathies Parkinson’s disease (PD) and Multiple system atrophy (MSA) — characterized by α-synuclein intracytoplasmic inclusions into, respectively, neurons and oligodendrocytes — are associated with impairment of the autophagy-lysosomal pathways (ALP). Increased expression of the master regulator of ALP, transcription factor EB (TFEB), is hypothesized to promote the clearance of WT α-synuclein and survival of dopaminergic neurons. Here, we explore the efficacy of targeted TFEB overexpression either in neurons or oligodendrocytes to reduce the pathological burden of α-synuclein in a PD rat model and a MSA mouse model. While TFEB neuronal expression was sufficient to prevent neurodegeneration in the PD model, we show that only TFEB oligodendroglial overexpression leads to neuroprotective effects in the MSA model. These beneficial effects were associated with a decreased accumulation of α-synuclein into oligodendrocytes through recovery of the ALP machinery. Our study demonstrates that the cell type where α-synuclein aggregates dictates the target of TFEB overexpression in order to be protective, paving the way for adapted therapies.
Authors
Marie-Laure Arotcarena, Mathieu Bourdenx, Nathalie Dutheil, Marie-Laure Thiolat, Evelyne Doudnikoff, Sandra Dovero, Andrea Ballabio, Pierre-Olivier Fernagut, Wassilios G. Meissner, Erwan Bezard, Benjamin Dehay
×Abstract
Glucagon and insulin are commonly believed to have counteracting effects on blood glucose levels. However, recent studies have demonstrated that glucagon has a physiologic role to activate β cells and enhance insulin secretion. To date, the actions of glucagon have been studied mostly in fasting or hypoglycemic states, yet it is clear that mixed-nutrient meals elicit secretion of both glucagon and insulin, suggesting that glucagon also contributes to glucose regulation in the postprandial state. We hypothesized that the elevated glycemia seen in the fed state would allow glucagon to stimulate insulin secretion and reduce blood glucose. In fact, exogenous glucagon given under fed conditions did robustly stimulate insulin secretion and lower glycemia. Exogenous glucagon given to fed Gcgr:Glp1rβcell–/– mice failed to stimulate insulin secretion or reduce glycemia, demonstrating the importance of an insulinotropic glucagon effect. The action of endogenous glucagon to reduce glycemia in the fed state was tested with administration of alanine, a potent glucagon secretagogue. Alanine raised blood glucose in fasted WT mice or fed Gcgr:Glp1rβcell–/– mice, conditions where glucagon is unable to stimulate β cell activity. However, alanine given to fed WT mice produced a decrease in glycemia, along with elevated insulin and glucagon levels. Overall, our data support a model in which glucagon serves as an insulinotropic hormone in the fed state and complements rather than opposes insulin action to maintain euglycemia.
Authors
Megan E. Capozzi, Jacob B. Wait, Jepchumba Koech, Andrew N. Gordon, Reilly W. Coch, Berit Svendsen, Brian Finan, David A. D’Alessio, Jonathan E. Campbell
×Abstract
BACKGROUND Cytokine biomarkers have already been used to predict acute graft-versus-host disease (aGVHD) onset, nonrelapse mortality, and overall survival in human and mouse models, but the consistency of the consequences between patients and mice has not been evaluated. Furthermore, no study about any biomarker or biomarker panel for aGVHD grading or steroid sensitivity of aGVHD patients simultaneously has been reported.METHODS Here we established an aGVHD mouse model and explored the relation between aGVHD onset and variations of some cytokines. Based on the results and latest progress, we selected 16 cytokines and compared their serum variations in aGVHD patients and non-aGVHD patients after allogeneic hematopoietic stem cell transplantation. Using protein microarray, we explored the relation between the cytokine levels and aGVHD-related events (onset, grading, and steroid sensitivity).RESULTS The increase of chemokine levels in murine aGVHD was very consistent with that of patients. We found obviously higher levels of IL-2, IL-4, Elafin, sST2, TLR4, and TNF-α, and lower levels of TGF-β in both aGVHD mouse models and aGVHD patients. In addition, patients with severe aGVHD showed increased IL-6, TLR4, TNF receptor 1 (TNFR1), and Elafin and decreased TGF-β. TLR4 and TNFR1 were significantly increased in steroid-refractory aGVHD patients compared with steroid-effective patients (P < 0.05).CONCLUSION A combination of TLR4, TNFR1, TGF-β, and Elafin could be a new 4-biomarker panel to assist aGVHD diagnosis, grading, and evaluation of steroid sensitivity for clinical aGVHD patients.TRIAL REGISTRATION ChiCTR1900022292 “Clinical Research of Umbilical Cord–Derived Mesenchymal Stromal Cells in the Prophylaxis of Graft-Versus-Host Disease After HLA-Haploidentical Stem-Cell Transplantation.”FUNDING National Key Research Program, National Natural Science Foundation of China, Chongqing Social Career and People’s Livelihood Security Science and Technology Innovation Project, Fundamental and Frontier Research Program of Chongqing, and Foundation of Xinqiao Hospital.
Authors
Xiaoping Li, Ting Chen, Qiangguo Gao, Wei Zhang, Yunshuo Xiao, Wen Zhu, Lingyu Zeng, Zhenyu Li, Shijie Yang, Rui Wang, Xiaoqi Wang, Yimei Feng, Xi Zhang
×Abstract
BACKGROUND Lewy body diseases, a family of aging-related neurodegenerative disorders, entail loss of the catecholamine dopamine in the nigrostriatal system and equally severe deficiency of the closely related catecholamine norepinephrine in the heart. The myocardial noradrenergic lesion is associated with major nonmotor symptoms and decreased survival. Numerous mechanisms determine norepinephrine stores, and which of these are altered in Lewy body diseases has not been examined in an integrated way. We used a computational modeling approach to assess comprehensively pathways of cardiac norepinephrine synthesis, storage, release, reuptake, and metabolism in Lewy body diseases. Application of a potentially novel kinetic model identified a pattern of dysfunctional steps contributing to norepinephrine deficiency. We then tested predictions from the model in a new cohort of Parkinson disease patients.METHODS Rate constants were calculated for 17 reactions determining intraneuronal norepinephrine stores. Model predictions were tested by measuring postmortem apical ventricular concentrations and concentration ratios of catechols in controls and patients with Parkinson disease.RESULTS The model identified low rate constants for 3 types of processes in the Lewy body group: catecholamine biosynthesis via tyrosine hydroxylase and aromatic l-amino acid decarboxylase, vesicular storage of dopamine and norepinephrine, and neuronal norepinephrine reuptake via the cell membrane norepinephrine transporter. Postmortem catechols and catechol ratios confirmed this triad of model-predicted functional abnormalities.CONCLUSION Denervation-independent impairments of neurotransmitter biosynthesis, vesicular sequestration, and norepinephrine recycling contribute to the myocardial norepinephrine deficiency attending Lewy body diseases. A proportion of cardiac sympathetic nerves are “sick but not dead,” suggesting targeted disease modification strategies might retard clinical progression.FUNDING Division of Intramural Research, NINDS.
Authors
David S. Goldstein, Mark J. Pekker, Graeme Eisenhofer, Yehonatan Sharabi
×Abstract
Immune homeostasis in the gut-associated lymphoid tissues (GALT) is critical to prevent the development of inadvertent pathologies. B cells, as the producers of antibodies and cytokines, play an important role in maintaining the GALT homeostasis. However, the mechanism by which B cells specifically direct their responses toward non-self-antigens and become ignorant to self-antigens in the GALT is not known. Therefore, we developed what we believe to be a novel mouse model by expressing duck egg lysozyme (DEL) in gut epithelial cells in presence of HEL-reactive B cells. Notably, we observed a transient activation and rapid deletion of self-reactive B cells in Peyer’s patches and mesenteric lymph nodes upon self-antigen exposure. The survival of self-reactive B cells upon exposure to their self-antigen was partially rescued by blocking receptor editing but could be completely rescued by stronger survival signal, such as ectopic expression of BCL2. Importantly, rescuing the self-reactive B cells promoted production of autoantibodies and gut inflammation. Mechanistically, we identify a specific activation of TGF-β signaling in self-reactive B cells in the gut and a critical role of this pathway in maintaining peripheral tolerance. Collectively, our studies describe functional consequences and the fate of self-reactive B cells in GALT and provide potentially novel mechanistic insights governing self-tolerance of B cells in the gut.
Authors
Ashima Shukla, Cindi Chen, Julia Jellusova, Charlotte R. Leung, Elaine Kao, Numana Bhat, Wai W. Lin, John R. Apgar, Robert C. Rickert
×Abstract
Prion disease is a fatal, incurable neurodegenerative disease of humans and other mammals caused by conversion of cellular prion protein (PrPC) into a self-propagating neurotoxic conformer (prions; PrPSc). Strong genetic proofs of concept support lowering PrP expression as a therapeutic strategy. Antisense oligonucleotides (ASOs) can provide a practical route to lowering 1 target mRNA in the brain, but their development for prion disease has been hindered by 3 unresolved issues from prior work: uncertainty about mechanism of action, unclear potential for efficacy against established prion infection, and poor tolerability of drug delivery by osmotic pumps. Here, we test ASOs delivered by bolus intracerebroventricular injection to intracerebrally prion-infected WT mice. Prophylactic treatments given every 2–3 months extended survival times 61%–98%, and a single injection at 120 days after infection, near the onset of clinical signs, extended survival 55% (87 days). In contrast, a nontargeting control ASO was ineffective. Thus, PrP lowering is the mechanism of action of ASOs effective against prion disease in vivo, and infrequent — or even single — bolus injections of ASOs can slow prion neuropathogenesis and markedly extend survival, even when initiated near clinical signs. These findings should empower development of PrP-lowering therapy for prion disease.
Authors
Gregory J. Raymond, Hien Tran Zhao, Brent Race, Lynne D. Raymond, Katie Williams, Eric E. Swayze, Samantha Graffam, Jason Le, Tyler Caron, Jacquelyn Stathopoulos, Rhonda O’Keefe, Lori L. Lubke, Andrew G. Reidenbach, Allison Kraus, Stuart L. Schreiber, Curt Mazur, Deborah E. Cabin, Jeffrey B. Carroll, Eric Vallabh Minikel, Holly Kordasiewicz, Byron Caughey, Sonia M. Vallabh
×Abstract
Cardiac pressure overload — for example, due to aortic stenosis — induces irreversible myocardial dysfunction, cardiomyocyte hypertrophy, and interstitial fibrosis in patients. In contrast with adult mice, neonatal mice can efficiently regenerate the heart after injury in the first week after birth. To decipher whether insufficient cardiac regeneration contributes to the progression of pressure overload–dependent disease, we established a transverse aortic constriction protocol in neonatal mice (nTAC). nTAC in the nonregenerative stage (at P7) induced cardiac dysfunction, myocardial fibrosis, and cardiomyocyte hypertrophy. In contrast, nTAC in the regenerative stage (at P1) largely prevented these maladaptive responses and was, in particular, associated with enhanced myocardial angiogenesis and increased cardiomyocyte proliferation, which both supported adaptation during nTAC. A comparative transcriptomic analysis between hearts after regenerative versus nonregenerative nTAC suggested the transcription factor GATA4 as master regulator of the regenerative gene program. Indeed, cardiomyocyte-specific deletion of GATA4 converted the regenerative nTAC into a nonregenerative, maladaptive response. Our new nTAC model can be used to identify mediators of adaptation during pressure overload and to discover potential therapeutic strategies.
Authors
Mona Malek Mohammadi, Aya Abouissa, Isyatul Azizah, Yinou Xie, Julio Cordero, Amir Shirvani, Anna Gigina, Maren Engelhardt, Felix A. Trogisch, Robert Geffers, Gergana Dobreva, Johann Bauersachs, Joerg Heineke
