Evidence indicates that neuroinflammation contributes to motor neuron degeneration in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease leading to progressive muscular paralysis. However, it remains elusive whether inflammatory cells can interact with degenerating distal motor axons, influencing the progressive denervation of neuromuscular junctions (NMJs). By analyzing the muscle extensor digitorum longus (EDL) following paralysis onset in the SOD1G93A rat model, we have observed a massive infiltration and degranulation of mast cells, starting after paralysis onset and correlating with progressive NMJ denervation. Remarkably, mast cells accumulated around degenerating motor axons and NMJs, and were also associated with macrophages. Mast cell accumulation and degranulation in paralytic EDL muscle was prevented by systemic treatment over 15 days with masitinib, a tyrosine kinase inhibitor currently in clinical trials for ALS exhibiting pharmacological activity affecting mast cells and microglia. Masitinib-induced mast cell reduction resulted in a 35% decrease in NMJ denervation and reduced motor deficits as compared with vehicle-treated rats. Masitinib also normalized macrophage infiltration, as well as regressive changes in Schwann cells and capillary networks observed in advanced paralysis. These findings provide evidence for mast cell contribution to distal axonopathy and paralysis progression in ALS, a mechanism that can be therapeutically targeted by masitinib.
Emiliano Trias, Sofía Ibarburu, Romina Barreto-Núñez, Valentina Varela, Ivan C. Moura, Patrice Dubreuil, Olivier Hermine, Joseph S. Beckman, Luis Barbeito
Sickle cell disease (SCD) results from a point mutation in the β-globin gene forming hemoglobin S (HbS), which polymerizes in deoxygenated erythrocytes, triggering recurrent painful vaso-occlusive crises and chronic hemolytic anemia. Reactivation of fetal Hb (HbF) expression ameliorates these symptoms of SCD. Nuclear factor (erythroid derived-2)–like 2 (Nrf2) is a transcription factor that triggers cytoprotective and antioxidant pathways to limit oxidative damage and inflammation and increases HbF synthesis in CD34+ stem cell–derived erythroid progenitors. We investigated the ability of dimethyl fumarate (DMF), a small-molecule Nrf2 agonist, to activate γ-globin transcription and enhance HbF in tissue culture and in murine and primate models. DMF recruited Nrf2 to the γ-globin promoters and the locus control region of the β-globin locus in erythroleukemia cells, elevated HbF in SCD donor–derived erythroid progenitors, and reduced hypoxia-induced sickling. Chronic DMF administration in SCD mice induced HbF and increased Nrf2-dependent genes to detoxify heme and limit inflammation. This improved hematological parameters, reduced plasma-free Hb, and attenuated inflammatory markers. Chronic DMF administration to nonanemic primates increased γ-globin mRNA in BM and HbF protein in rbc. DMF represents a potential therapy for SCD to induce HbF and augment vasoprotection and heme detoxification.
Sriram Krishnamoorthy, Betty Pace, Dipti Gupta, Sarah Sturtevant, Biaoru Li, Levi Makala, Julia Brittain, Nancy Moore, Benjamin F. Vieira, Timothy Thullen, Ivan Stone, Huo Li, William E. Hobbs, David R. Light
Eosinophilic esophagitis (EoE) is an allergic inflammatory disease of the esophagus mediated by an IL-13–driven epithelial cell transcriptional program. Herein, we show that the cytoskeletal protein synaptopodin (SYNPO), previously associated with podocytes, is constitutively expressed in esophageal epithelium and induced during allergic inflammation. In addition, we show that the SYNPO gene is transcriptionally and epigenetically regulated by IL-13 in esophageal epithelial cells. SYNPO was expressed in the basal layer of homeostatic esophageal epithelium, colocalized with actin filaments, and expanded into the suprabasal epithelium in EoE patients, where expression was elevated 25-fold compared with control individuals. The expression level of SYNPO in esophageal biopsies correlated with esophageal eosinophil density and was improved following anti–IL-13 treatment in EoE patients. In esophageal epithelial cells, SYNPO gene silencing reduced epithelial motility in a wound healing model, whereas SYNPO overexpression impaired epithelial barrier integrity and reduced esophageal differentiation. Taken together, we demonstrate that SYNPO is induced by IL-13 in vitro and in vivo, is a nonredundant regulator of epithelial cell barrier function and motility, and is likely involved in EoE pathogenesis.
Mark Rochman, Jared Travers, J. Pablo Abonia, Julie M. Caldwell, Marc E. Rothenberg
Mycobacterium tuberculosis (Mtb) is a global health threat, compounded by the emergence of drug-resistant strains. A hallmark of pulmonary tuberculosis (TB) is the formation of hypoxic necrotic granulomas, which upon disintegration, release infectious Mtb. Furthermore, hypoxic necrotic granulomas are associated with increased disease severity and provide a niche for drug-resistant Mtb. However, the host immune responses that promote the development of hypoxic TB granulomas are not well described. Using a necrotic Mtb mouse model, we show that loss of Mtb virulence factors, such as phenolic glycolipids, decreases the production of the proinflammatory cytokine IL-17 (also referred to as IL-17A). IL-17 production negatively regulates the development of hypoxic TB granulomas by limiting the expression of the transcription factor hypoxia-inducible factor 1α (HIF1α). In human TB patients, HIF1α mRNA expression is increased. Through genotyping and association analyses in human samples, we identified a link between the single nucleotide polymorphism rs2275913 in the IL-17 promoter (–197G/G), which is associated with decreased IL-17 production upon stimulation with Mtb cell wall. Together, our data highlight a potentially novel role for IL-17 in limiting the development of hypoxic necrotic granulomas and reducing disease severity in TB.
Racquel Domingo-Gonzalez, Shibali Das, Kristin L. Griffiths, Mushtaq Ahmed, Monika Bambouskova, Radha Gopal, Suhas Gondi, Marcela Muñoz-Torrico, Miguel A. Salazar-Lezama, Alfredo Cruz-Lagunas, Luis Jiménez-Álvarez, Gustavo Ramirez-Martinez, Ramón Espinosa-Soto, Tamanna Sultana, James Lyons-Weiler, Todd A. Reinhart, Jesus Arcos, Maria de la Luz Garcia-Hernandez, Michael A. Mastrangelo, Noor Al-Hammadi, Reid Townsend, Joan-Miquel Balada-Llasat, Jordi B. Torrelles, Gilla Kaplan, William Horne, Jay K. Kolls, Maxim N. Artyomov, Javier Rangel-Moreno, Joaquín Zúñiga, Shabaana A. Khader
BACKGROUND. HIV-infected individuals, even well controlled with combined antiretroviral therapy (cART), have systemic inflammation and comorbidities. Substance P (SP) is an undecapeptide, which mediates neurotransmission and inflammation through its cognate neurokinin 1 receptor (NK1R). Plasma SP levels are elevated in HIV-infected individuals. The FDA-approved antiemetic aprepitant, an NK1R antagonist, has anti-HIV effects and antiinflammatory actions. We evaluated the safety, pharmacokinetics, and antiinflammatory properties of aprepitant in HIV-positive individuals receiving cART. METHODS. We conducted a phase 1B study of 12 HIV-positive individuals on a ritonavir-containing regimen (HIV viral load less than 40 copies/ml and CD4 > 400 cells/μl). Participants received open-label aprepitant 375 mg per day for 28 days and were followed for an additional 30 days. Changes in plasma levels of proinflammatory markers were assessed using flow cytometry, ELISA, luminex, and SOMAscan assays. RESULTS. The mean peak aprepitant plasma concentration was 30.7 ± 15.3 μg/ml at day 14 and 23.3 ± 12.3 μg/ml at day 28. Aprepitant treatment resulted in decreased plasma SP levels and affected 176 plasma proteins (56 after FDR) and several metabolic pathways, including inflammation and lipid metabolism. No change in soluble CD163 was observed. Aprepitant treatment was associated with a moderate increases in total and HDL cholesterol and affected select hematologic and metabolic markers, which returned to baseline levels 30 days after aprepitant treatment was stopped. There were 12 mild and 10 moderate adverse events (AE). CONCLUSIONS. Aprepitant is safe and well tolerated. The antiinflammatory properties of aprepitant make it a possible adjunctive therapy for comorbid conditions associated with HIV infection. TRIAL REGISTRATION. ClinicalTrials.gov (NCT02154360). FUNDING. This research was funded by NIH UO1 MH090325, P30 MH097488, and PO1 MH105303.
Sergei Spitsin, Pablo Tebas, Jeffrey S. Barrett, Vasiliki Pappa, Deborah Kim, Deanne Taylor, Dwight L. Evans, Steven D. Douglas
Chronic inflammatory diseases, such as periodontal disease, associate with adverse wound healing in response to myocardial infarction (MI). The goal of this study was to elucidate the molecular basis for impaired cardiac wound healing in the setting of periodontal-induced chronic inflammation. Causal network analysis of 168 inflammatory and extracellular matrix genes revealed that chronic inflammation induced by a subseptic dose of Porphyromonas gingivalis lipopolysaccharide (LPS) exacerbated infarct expression of the proinflammatory cytokine Ccl12. Ccl12 prevented initiation of the reparative response by prolonging inflammation and inhibiting fibroblast conversion to myofibroblasts, resulting in diminished scar formation. Macrophage secretion of Ccl12 directly impaired fibronectin and collagen deposition and indirectly stimulated collagen degradation through upregulation of matrix metalloproteinase-2. In post-MI patients, circulating LPS levels strongly associated with the Ccl12 homologue monocyte chemotactic protein 1 (MCP-1). Patients with LPS levels ≥ 1 endotoxin units (EU)/ml (subseptic endotoxemia) at the time of hospitalization had increased end diastolic and systolic dimensions compared with post-MI patients with < 1 EU/ml, indicating that low yet pathological concentrations of circulating LPS adversely impact post-MI left ventricle (LV) remodeling by increasing MCP-1. Our study provides the first evidence to our knowledge that chronic inflammation inhibits reparative fibroblast activation and generates an unfavorable cardiac–healing environment through Ccl12-dependent mechanisms.
Kristine Y. DeLeon-Pennell, Rugmani Padmanabhan Iyer, Osasere K. Ero, Courtney A. Cates, Elizabeth R. Flynn, Presley L. Cannon, Mira Jung, De’Aries Shannon, Michael R. Garrett, William Buchanan, Michael E. Hall, Yonggang Ma, Merry L. Lindsey
BACKGROUND. Neuronal remodeling in human heart disease is not well understood. METHODS. Stellate ganglia from patients with cardiomyopathy (CMY) and refractory ventricular arrhythmias undergoing cardiac sympathetic denervation (n = 8), and from organ donors with normal hearts (n = 8) collected at the time of organ procurement were compared. Clinical data on all subjects were reviewed. Electron microscopy (EM), histologic, and immunohistochemical assessments of neurotransmitter profiles, glial activation and distribution, and lipofuscin deposition, a marker of oxidative stress, were quantified. RESULTS. In CMY specimens, lipofuscin deposits were larger, and present in more neurons (26.3% ± 6.3% vs. 16.7% ± 7.6%, P < 0.043), than age-matched controls. EM analysis revealed extensive mitochondrial degeneration in CMY specimens. T cell (CD3+) infiltration was identified in 60% of the CMY samples, with one case having large inflammatory nodules, while none were identified in controls. Myeloperoxidase-immunoreactive neutrophils were also identified at parenchymal sites distinct from inflammatory foci in CMY ganglia, but not in controls. The adrenergic phenotype of pathologic samples revealed a decrease in tyrosine hydroxylase staining intensity compared with controls. Evaluation of cholinergic phenotype by staining for the vesicular acetylcholine transporter revealed a low but comparable number of cholinergic neurons in ganglia from both groups and demonstrated that preganglionic cholinergic innervation was maintained in CMY ganglia. S100 staining (a glial cell marker) demonstrated no differences in glial distribution and relationship to neurons; however, glial activation demonstrated by glial fibrillary acidic protein (GFAP) staining was substantially increased in pathologic specimens compared with controls. CONCLUSIONS. Stellate ganglia from patients with CMY and arrhythmias demonstrate inflammation, neurochemical remodeling, oxidative stress, and satellite glial cell activation. These changes likely contribute to excessive and dysfunctional efferent sympathetic tone, and provide a rationale for sympathectomy as a treatment for arrhythmias in this population. FUNDING. This work was made possible by support from NIH grants HL125730 to OAA, GM107949 to DBH, and HL084261 and OT2OD023848 to KS.
Olujimi A. Ajijola, Donald B. Hoover, Thomas M. Simerly, T. Christopher Brown, Jane Yanagawa, Reshma M. Biniwale, Jay M. Lee, Ali Sadeghi, Negar Khanlou, Jeffrey L. Ardell, Kalyanam Shivkumar
Dendritic cells (DCs) are important in regulating immunity and tolerance and consist of functionally distinct subsets that differentially regulate T lymphocyte function. The underlying basis for this subset specificity is lacking, particularly in humans, where the classification of tissue DCs is currently incomplete. Examination of healthy human epidermal Langerhans cells and dermal skin cells revealed a tissue CD5-expressing DC subtype. The CD5+ DCs were potent inducers of cytotoxic T cells and Th22 cells. The products of these T cells, IL-22 and IFN-γ, play a key role in the pathogenesis of psoriasis. Remarkably, CD5+ DCs were significantly enriched in lesional psoriatic skin compared with distal tissues, suggesting their involvement in the disease. We show that CD5+ DCs can be differentiated from hematopoietic progenitor cells independently of the CD5– DCs. A progenitor population found in human cord blood and in the dermal skin layer, marked as CD34–CD123+CD117dimCD45RA+, was an immediate precursor of these CD11c+CD1c+CD5+ DCs. Overall, our discovery of the CD5-expressing DC subtype suggests that strategies to regulate their composition or function in the skin will represent an innovative approach for the treatment of immune-mediated disorders in and beyond the skin.
Daniel Korenfeld, Laurent Gorvel, Adiel Munk, Joshua Man, Andras Schaffer, Thomas Tung, Caroline Mann, Eynav Klechevsky
Oxidative stress is important in the pathogenesis of allergic asthma. Extracellular superoxide dismutase (EC-SOD; SOD3) is the major antioxidant in lungs, but its role in allergic asthma is unknown. Here we report that asthmatics have increased SOD3 transcript levels in sputum and that a single nucleotide polymorphism (SNP) in SOD3 (R213G; rs1799895) changes lung distribution of EC-SOD, and decreases likelihood of asthma-related symptoms. Knockin mice analogous to the human R213G SNP had lower airway hyperresponsiveness, inflammation, and mucus hypersecretion with decreased interleukin-33 (IL-33) in bronchoalveolar lavage fluid and reduced type II innate lymphoid cells (ILC2s) in lungs. SOD mimetic (Mn (III) tetrakis (N-ethylpyridinium-2-yl) porphyrin) attenuated Alternaria-induced expression of IL-33 and IL-8 release in BEAS-2B cells. These results suggest that R213G SNP potentially benefits its carriers by resulting in high EC-SOD in airway-lining fluid, which ameliorates allergic airway inflammation by dampening the innate immune response, including IL-33/ST2–mediated changes in ILC2s.
Rohit Gaurav, Jason T. Varasteh, Michael R. Weaver, Sean R. Jacobson, Laura Hernandez-Lagunas, Qing Liu, Eva Nozik-Grayck, Hong Wei Chu, Rafeul Alam, Børge G. Nordestgaard, Camilla J. Kobylecki, Shoaib Afzal, Geoffrey L. Chupp, Russell P. Bowler
MTG16 is a member of the myeloid translocation gene (MTG) family of transcriptional corepressors. While MTGs were originally identified in chromosomal translocations in acute myeloid leukemia, recent studies have uncovered a role in intestinal biology. For example, Mtg16–/– mice have increased intestinal proliferation and are more sensitive to intestinal injury in colitis models. MTG16 is also underexpressed in patients with moderate/severe ulcerative colitis. Based on these findings, we postulated that MTG16 might protect against colitis-associated carcinogenesis. MTG16 was downregulated at the protein and RNA levels in patients with inflammatory bowel disease and in those with colitis-associated carcinoma. Mtg16–/– mice subjected to inflammatory carcinogenesis modeling exhibited worse colitis and increased tumor multiplicity and size. Loss of MTG16 also increased severity of dysplasia, apoptosis, proliferation, DNA damage, and WNT signaling. Moreover, transplantation of WT marrow into Mtg16–/– mice failed to rescue the Mtg16–/– protumorigenic phenotypes, indicating an epithelium-specific role for MTG16. While MTG dysfunction is widely appreciated in hematopoietic malignancies, the role of this gene family in epithelial homeostasis, and in colon cancer, was unrealized. This report identifies MTG16 as an important modulator of colitis and tumor development in inflammatory carcinogenesis.
Elizabeth M. McDonough, Caitlyn W. Barrett, Bobak Parang, Mukul K. Mittal, J. Joshua Smith, Amber M. Bradley, Yash A. Choksi, Lori A. Coburn, Sarah P. Short, Joshua J. Thompson, Baolin Zhang, Shenika V. Poindexter, Melissa A. Fischer, Xi Chen, Jiang Li, Frank L. Revetta, Rishi Naik, M. Kay Washington, Michael J. Rosen, Scott W. Hiebert, Keith T. Wilson, Christopher S. Williams
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