Latest issue: June 6, 2019

In the issue

Abstract

Chimeric antigen receptor (CAR) T cell therapies have achieved promising outcomes in several cancers; however, more challenging oncology indications may necessitate advanced antigen receptor designs and functions. Here we describe a bipartite receptor system composed of separate antigen-targeting and signal transduction polypeptides, each containing an extracellular dimerization domain. We demonstrate that T cell activation remains antigen dependent but can only be achieved in the presence of a dimerizing drug, rapamycin. Studies performed in vitro and in xenograft mouse models illustrate equivalent to superior antitumor potency compared with currently used CAR designs, and at rapamycin concentrations well below immunosuppressive levels. We further show that the extracellular positioning of the dimerization domains enables the administration of recombinant retargeting modules, potentially extending antigen targeting. Overall, this regulatable CAR design has exquisite drug sensitivity, provides robust antitumor responses, and is flexible for multiplex antigen targeting or retargeting, which may further assist the development of safe, potent, and durable T cell therapeutics.

Authors

Wai-Hang Leung, Joel Gay, Unja Martin, Tracy E. Garrett, Holly M. Horton, Michael T. Certo, Bruce R. Blazar, Richard A. Morgan, Philip D. Gregory, Jordan Jarjour, Alexander Astrakhan

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Abstract

Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent, and potentially morbid, disease that affects one-third of the US population. Normal liver safely accommodates lipid excess during fasting or carbohydrate restriction by increasing their oxidation to acetyl-CoA and ketones, yet lipid excess during NAFLD leads to hyperglycemia and, in some, steatohepatitis. To examine potential mechanisms, we studied flux through pathways of hepatic oxidative metabolism and gluconeogenesis using 5 simultaneous stable isotope tracers in ketotic (24-hour-fasted) individuals with a wide range of hepatic triglyceride content levels (0%–52%). Ketogenesis was progressively impaired as hepatic steatosis and glycemia worsened. Conversely, the alternative pathway for acetyl-CoA metabolism, oxidation in the tricarboxylic acid (TCA) cycle, was upregulated in NAFLD as ketone production diminished and positively correlated with rates of gluconeogenesis and plasma glucose concentrations. Increased respiration and energy generation that occurred in liver when β-oxidation and TCA cycle activity were coupled may explain these findings, inasmuch as calculated hepatic oxygen consumption was higher during fatty liver and highly correlated with gluconeogenesis. These findings demonstrate that increased glucose production and hyperglycemia in NAFLD is a consequence not of acetyl-CoA production per se, but rather of how acetyl-CoA is further metabolized in liver.

Authors

Justin A. Fletcher, Stanisław Deja, Santhosh Satapati, Xiaorong Fu, Shawn C. Burgess, Jeffrey D. Browning

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Abstract

In the current preclinical study, we demonstrate the therapeutic potential of sarcospan (SSPN) overexpression to alleviate cardiomyopathy associated with Duchenne muscular dystrophy (DMD) utilizing dystrophin-deficient mdx mice with utrophin haploinsufficiency that more accurately represent the severe disease course of human DMD. SSPN interacts with dystrophin, the DMD disease gene product, and its autosomal paralog utrophin, which is upregulated in DMD as a partial compensatory mechanism. SSPN-Tg mice have enhanced abundance of fully glycosylated α-dystroglycan, which may further protect dystrophin-deficient cardiac membranes. Baseline echocardiography revealed that SSPN improves systolic function and hypertrophic indices in mdx and mdx:utr-heterozygous mice. Assessment of SSPN-Tg mdx mice by hemodynamic pressure-volume methods highlighted enhanced systolic performance compared with mdx controls. SSPN restored cardiac sarcolemma stability, the primary defect in DMD disease; reduced fibrotic response; and improved contractile function. We demonstrate that SSPN ameliorated more advanced cardiac disease in the context of diminished sarcolemma expression of utrophin and β1D integrin, which mitigate disease severity, and partially restored responsiveness to β-adrenergic stimulation. Overall, our current and previous findings suggest that SSPN overexpression in DMD mouse models positively affects skeletal, pulmonary, and cardiac performance by addressing the stability of proteins at the sarcolemma that protect the heart from injury, supporting SSPN and membrane stabilization as a therapeutic target for DMD.

Authors

Michelle S. Parvatiyar, Alexandra J. Brownstein, Rosemeire M. Kanashiro-Takeuchi, Judd R. Collado, Karissa M. Dieseldorff Jones, Jay Gopal, Katherine G. Hammond, Jamie L. Marshall, Abel Ferrel, Aaron M. Beedle, Jeffrey S. Chamberlain, Jose Renato Pinto, Rachelle H. Crosbie

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Abstract

Induction of a potent CD4 and CD8 T cell response against tumor-specific and tumor-associated antigens is critical for eliminating tumor cells. Recent vaccination strategies have been hampered by an inefficacious and low-amplitude immune response. In this article, we describe a self-adjuvanted chimeric protein vaccine platform to address these challenges, characterized by a multidomain construction incorporating (a) a cell-penetrating peptide allowing internalization of several multiantigenic MHC-restricted peptides within (b) the multiantigenic domain and (c) a TLR2/4 agonist domain. Functionality of the resulting chimeric protein is based on the combined effect of the above-mentioned 3 different domains for simultaneous activation of antigen-presenting cells and antigen cross-presentation, leading to an efficacious multiantigenic and multiallelic cellular immune response. Helper and cytotoxic T cell responses were observed against model-, neo-, and self-antigens and were highly potent in several murine tumor models. The safety and the immunogenicity of a human vaccine candidate designed for colorectal cancer treatment was demonstrated in a nonhuman primate model. This therapeutic vaccine approach, which we believe to be newly engineered, is promising for the treatment of poorly infiltrated tumors that do not respond to currently marketed immunotherapies.

Authors

Elodie Belnoue, Jean-François Mayol, Susanna Carboni, Wilma Di Berardino Besson, Eloise Dupuychaffray, Annika Nelde, Stefan Stevanovic, Marie-Laure Santiago-Raber, Paul R. Walker, Madiha Derouazi

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Abstract

Atrial fibrillation (AF) is the most common cardiac arrhythmia and accounts for substantial morbidity and mortality. Recently, we created a mouse model with spontaneous and sustained AF caused by a mutation in the NaV1.5 channel (F1759A) that enhances persistent Na+ current, thereby enabling the investigation of molecular mechanisms that cause AF and the identification of potentially novel treatment strategies. The mice have regional heterogeneity of action potential duration of the atria similar to observations in patients with AF. In these mice, we found that the initiation and persistence of the rotational reentrant AF arrhythmias, known as spiral waves or rotors, were dependent upon action potential duration heterogeneity. The centers of the rotors were localized to regions of greatest heterogeneity of the action potential duration. Pharmacologically attenuating the action potential duration heterogeneity reduced both spontaneous and pacing-induced AF. Computer-based simulations also demonstrated that the action potential duration heterogeneity is required to generate rotors that manifest as AF. Taken together, these findings suggest that action potential duration heterogeneity in mice and humans is one mechanism by which AF is initiated and that reducing action potential duration heterogeneity can lessen the burden of AF.

Authors

Uma Mahesh R. Avula, Jeffrey Abrams, Alexander Katchman, Sergey Zakharov, Sergey Mironov, Joseph Bayne, Daniel Roybal, Anirudh Gorti, Lin Yang, Vivek Iyer, Marc Waase, Deepak Saluja, Edward J. Ciaccio, Hasan Garan, Andrew R. Marks, Steven O. Marx, Elaine Y. Wan

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Abstract

Traumatic brain injury (TBI) causes cortical dysfunction and can lead to posttraumatic epilepsy. Multiple studies demonstrate that GABAergic inhibitory network function is compromised following TBI, which may contribute to hyperexcitability and motor, behavioral, and cognitive deficits. Preserving the function of GABAergic interneurons, therefore, is a rational therapeutic strategy to preserve cortical function after TBI and prevent long-term clinical complications. Here, we explored an approach based on the ketogenic diet, a neuroprotective and anticonvulsant dietary therapy that results in reduced glycolysis and increased ketosis. Utilizing a pharmacologic inhibitor of glycolysis (2-deoxyglucose, or 2-DG), we found that acute in vitro application of 2-DG decreased the excitability of excitatory neurons, but not inhibitory interneurons, in cortical slices from naive mice. Employing the controlled cortical impact (CCI) model of TBI in mice, we found that in vitro 2-DG treatment rapidly attenuated epileptiform activity seen in acute cortical slices 3–5 weeks after TBI. One week of in vivo 2-DG treatment immediately after TBI prevented the development of epileptiform activity, restored excitatory and inhibitory synaptic activity, and attenuated the loss of parvalbumin-expressing inhibitory interneurons. In summary, 2-DG may have therapeutic potential to restore network function following TBI.

Authors

Jenny B. Koenig, David Cantu, Cho Low, Mary Sommer, Farzad Noubary, Danielle Croker, Michael Whalen, Dong Kong, Chris G. Dulla

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Abstract

Preneoplastic lesions carry many of the antigenic targets found in cancer cells but often exhibit prolonged dormancy. Understanding how the host response to premalignancy is maintained and altered during malignant transformation is needed to prevent cancer. To understand the immune microenvironment in precursor monoclonal gammopathy of undetermined significance (MGUS) and myeloma, we analyzed bone marrow immune cells from 12 healthy donors and 26 patients with MGUS/myeloma by mass cytometry and concurrently profiled transcriptomes of 42,606 single immune cells from these bone marrow samples. Compared with age-matched healthy donors, memory T cells from both MGUS and myeloma patients exhibited greater terminal effector differentiation. However, memory T cells in MGUS show greater enrichment of stem-like TCF1/7hi cells. Clusters of T cells with stem-like and tissue residence genes were also found to be enriched in MGUS by single-cell transcriptome analysis. Early changes in both NK and myeloid cells were also observed in MGUS. Enrichment of stem-like T cells correlated with a distinct genomic profile of myeloid cells and levels of Dickkopf-1 in bone marrow plasma. These data describe the landscape of changes in both innate and adaptive immunity in premalignancy and suggest that attrition of the bone marrow–resident T cell compartment because of loss of stem-like cells may underlie loss of immune surveillance in myeloma.

Authors

Jithendra Kini Bailur, Samuel S. McCachren, Deon B. Doxie, Mahesh Shrestha, Katherine Pendleton, Ajay K. Nooka, Natalia Neparidze, Terri L. Parker, Noffar Bar, Jonathan L. Kaufman, Craig C. Hofmeister, Lawrence H. Boise, Sagar Lonial, Melissa L. Kemp, Kavita M. Dhodapkar, Madhav V. Dhodapkar

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Abstract

T and B cells have been implicated in hypertension, but the mechanisms by which they produce a coordinated response is unknown. T follicular helper (Tfh) cells that produce IL-21 promote germinal center (GC) B cell responses, leading to Ig production. Here we investigate the role of IL-21 and Tfh cells in hypertension. In response to angiotensin II–induced (Ang II–induced) hypertension, T cell IL-21 production was increased, and Il21–/– mice developed blunted hypertension, attenuated vascular end-organ damage, and decreased IL-17A and IFN-γ production. Tfh-like cells and GC B cells accumulated in the aorta, and plasma IgG1 was increased in hypertensive WT but not Il21–/– mice. Furthermore, Tfh cell–deficient mice developed blunted hypertension and vascular hypertrophy in response to Ang II infusion. Importantly, IL-21 neutralization reduced BP and reversed endothelial dysfunction and vascular inflammation. Moreover, recombinant IL-21 impaired endothelium-dependent relaxation ex vivo and decreased NO production from cultured endothelial cells. Finally, we show in humans that peripheral blood T cell production of IL-21 correlated with systolic BP and IL-17A production. These data suggest that IL-21 may be a novel therapeutic target for the treatment of hypertension and its micro- and macrovascular complications.

Authors

Bethany L. Dale, Arvind K. Pandey, Yuhan Chen, Charles D. Smart, Fanny Laroumanie, Mingfang Ao, Liang Xiao, Anna E. Dikalova, Sergey I. Dikalov, Fernando Elijovich, Jason D. Foss, Natalia R. Barbaro, Justin P. Van Beusecum, Serpil M. Deger, Aseel Alsouqi, Hana A. Itani, Allison E. Norlander, Matthew R. Alexander, Shilin Zhao, T. Alp Ikizler, Holly M. Scott Algood, Meena S. Madhur

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Abstract

Right ventricular (RV) dysfunction is highly prevalent across cardiopulmonary diseases and independently predicts death in both heart failure (HF) and pulmonary hypertension (PH). Progression towards RV failure (RVF) can occur in spite of optimal medical treatment of HF or PH, highlighting current insufficient understanding of RVF molecular pathophysiology. To identify molecular mechanisms that may distinctly underlie RVF, we investigated the cardiac ventricular transcriptome of advanced-HF patients, with and without RVF. Using an integrated systems genomic and functional biology approach, we identified an RVF-specific gene module, for which WIPI1 served as a hub and HSPB6 and MAP4 as drivers, and confirmed the ventricular specificity of Wipi1, Hspb6, and Map4 transcriptional changes in adult murine models of pressure overload–induced RV versus left ventricular failure. We uncovered a shift towards noncanonical autophagy in the failing RV that correlated with RV-specific Wipi1 upregulation. In vitro siRNA silencing of Wipi1 in neonatal rat ventricular myocytes limited noncanonical autophagy and blunted aldosterone-induced mitochondrial superoxide levels. Our findings suggest that Wipi1 regulates mitochondrial oxidative signaling and noncanonical autophagy in cardiac myocytes. Together with our human transcriptomic analysis and corroborating studies in an RVF mouse model, these data render Wipi1 a potential target for RV-directed HF therapy.

Authors

Christos Tzimas, Christoph D. Rau, Petra E. Buergisser, Gaston Jean-Louis Jr., Katherine Lee, Jeffrey Chukwuneke, Wen Dun, Yibin Wang, Emily J. Tsai

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Abstract

Plasma calcium (Ca2+) is maintained by amending the release of parathyroid hormone and through direct effects of the Ca2+-sensing receptor (CaSR) in the renal tubule. Combined, these mechanisms alter intestinal Ca2+ absorption by modulating 1,25-dihydroxyvitamin D3 production, bone resorption, and renal Ca2+ excretion. The CaSR is a therapeutic target in the treatment of secondary hyperparathyroidism and hypocalcemia, a common complication of calcimimetic therapy. The CaSR is also expressed in intestinal epithelium; however, a direct role in regulating local intestinal Ca2+ absorption is unknown. Chronic CaSR activation decreased expression of genes involved in Ca2+ absorption. In Ussing chambers, increasing extracellular Ca2+ or basolateral application of the calcimimetic cinacalcet decreased net Ca2+ absorption across intestinal preparations acutely. Conversely, Ca2+ absorption increased with decreasing extracellular Ca2+ concentration. These responses were absent in mice expressing a nonfunctional TRPV6, TRPV6D541A. Cinacalcet also attenuated Ca2+ fluxes through TRPV6 in Xenopus oocytes when coexpressed with the CaSR. Moreover, the phospholipase C inhibitor U73122 prevented cinacalcet-mediated inhibition of Ca2+ flux. These results reveal a regulatory pathway whereby activation of the CaSR in the basolateral membrane of the intestine directly attenuates local Ca2+ absorption via TRPV6 to prevent hypercalcemia and help explain how calcimimetics induce hypocalcemia.

Authors

Justin J. Lee, Xiong Liu, Debbie O’Neill, Megan R. Beggs, Petra Weissgerber, Veit Flockerzi, Xing-Zhen Chen, Henrik Dimke, R. Todd Alexander

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Abstract

BACKGROUND Cutaneous neurofibromas (cNFs) are physically disfiguring, are painful, and cause extensive psychologic harm in patients with neurofibromatosis type 1 (NF1). There is currently no effective medical treatment, and surgical procedures are inaccessible to most NF1 patients globally. Although research is underway to find an effective medical treatment for cNF, there is an urgent need to develop a surgical approach that is accessible to all NF1 patients worldwide with the skill set and equipment found in most general medical office settings. Here, we present a robust surgical approach to remove cNFs that does not require a sterile surgical field, uses accessible clinical equipment, and can be performed by any health care provider, including family practitioners and physician assistants.METHODS In a prospective case series, patients with NF1 underwent this surgical procedure, which removes multiple cNFs. The Dermatology Life Quality Index was given to subjects before and after the procedure as a surrogate measurement of patient satisfaction.RESULTS Eighty-three tumors were removed throughout the body from 12 individuals. Examination at follow-up visits revealed well-healed scars without infection or adverse events, including aberrant scarring. Patient satisfaction with the procedure was high, with significant improvements in symptoms, daily activities, leisure, personal relationships, and treatment experience (P = 0.00062).CONCLUSION This study demonstrates a robust surgical approach to manage cNFs, which can be accessed worldwide by individuals with NF1 and performed by a wide variety of medical specialists with high clinical efficacy and patient satisfaction.FUNDING The Burroughs Wellcome Fund, the National Cancer Institute of the NIH, the Neurofibromatosis Therapeutic Acceleration Program, the NF1 Research Consortium Fund, and the Giorgio Foundation.

Authors

Bahir H. Chamseddin, La’Nette Hernandez, Dezehree Solorzano, Juan Vega, Lu Q. Le

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Abstract

Potassium (K+) secretion by kidney tubule cells is central to electrolyte homeostasis in mammals. In the K+-secreting principal cells of the distal nephron, electrogenic Na+ transport by the epithelial sodium channel (ENaC) generates the electrical driving force for K+ transport across the apical membrane. Regulation of this process is attributable in part to aldosterone, which stimulates the gene transcription of the ENaC-regulatory kinase, SGK1. However, a wide range of evidence supports the conclusion that an unidentified aldosterone-independent pathway exists. We show here that in principal cells, K+ itself acts through the type 2 mTOR complex (mTORC2) to activate SGK1, which stimulates ENaC to enhance K+ excretion. The effect depends on changes in K+ concentration on the blood side of the cells, and requires basolateral membrane K+-channel activity. However, it does not depend on changes in aldosterone, or on enhanced distal delivery of Na+ from upstream nephron segments. These data strongly support the idea that K+ is sensed directly by principal cells to stimulate its own secretion by activating the mTORC2/SGK1 signaling module, and stimulate ENaC. We propose that this local effect acts in concert with aldosterone and increased Na+ delivery from upstream nephron segments to sustain K+ homeostasis.

Authors

Mads Vaarby Sørensen, Bidisha Saha, Iben Skov Jensen, Peng Wu, Niklas Ayasse, Catherine E. Gleason, Samuel Levi Svendsen, Wen-Hui Wang, David Pearce

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Abstract

Enchondroma and chondrosarcoma are the most common benign and malignant cartilaginous neoplasms. Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) are present in the majority of these tumors. We performed RNA-seq analysis on chondrocytes from Col2a1Cre;Idh1LSL/+ animals and found that genes implied in the cholesterol synthesis pathway were significantly upregulated in the mutant chondrocytes. We examined the phenotypic effect of inhibiting intracellular cholesterol biosynthesis on enchondroma formation by conditionally deleting sterol regulatory element–binding protein cleavage-activating protein (SCAP), a protein activating intracellular cholesterol synthesis, in IDH1 mutant mice. We found fewer enchondromas in animals lacking SCAP. Furthermore, in chondrosarcomas, pharmacological inhibition of intracellular cholesterol synthesis substantially reduced chondrosarcoma cell viability in vitro and suppressed tumor growth in vivo. Taken together, these data suggest that intracellular cholesterol synthesis is a potential therapeutic target for enchondromas and chondrosarcomas.

Authors

Hongyuan Zhang, Qingxia Wei, Hidetoshi Tsushima, Vijitha Puviindran, Yuning J. Tang, Sinthu Pathmanapan, Raymond Poon, Eyal Ramu, Mushriq Al-Jazrawe, Jay Wunder, Benjamin A. Alman

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Abstract

Biallelic inactivating mutations in DOCK8 cause a combined immunodeficiency characterized by severe pathogen infections, eczema, allergies, malignancy, and impaired humoral responses. These clinical features result from functional defects in most lymphocyte lineages. Thus, DOCK8 plays a key role in immune cell function. Hematopoietic stem cell transplant (HSCT) is curative for DOCK8 deficiency. While previous reports have described clinical outcomes for DOCK8 deficiency following HSCT, the effect on lymphocyte reconstitution and function has not been investigated. Our study determined whether defects in lymphocyte differentiation and function in DOCK8-deficient patients were restored following HSCT. DOCK8-deficient T and B lymphocytes exhibited aberrant activation and effector function in vivo and in vitro. Frequencies of αβ T and MAIT cells were reduced, while γδT cells were increased in DOCK8-deficient patients. HSCT improved abnormal lymphocyte function in DOCK8-deficient patients. Elevated total and allergen-specific IgE in DOCK8-deficient patients decreased over time following HSCT. Our results document the extensive catalog of cellular defects in DOCK8-deficient patients and the efficacy of HSCT in correcting these defects, concurrent with improvements in clinical phenotypes. Overall, our findings reveal mechanisms at a functional cellular level for improvements in clinical features of DOCK8 deficiency after HSCT, identify biomarkers that correlate with improved clinical outcomes, and inform the general dynamics of immune reconstitution in patients with monogenic immune disorders following HSCT.

Authors

Bethany A. Pillay, Danielle T. Avery, Joanne M. Smart, Theresa Cole, Sharon Choo, Damien Chan, Paul E. Gray, Katie Frith, Richard Mitchell, Tri Giang Phan, Melanie Wong, Dianne E. Campbell, Peter Hsu, John B. Ziegler, Jane Peake, Frank Alvaro, Capucine Picard, Jacinta Bustamante, Benedicte Neven, Andrew J. Cant, Gulbu Uzel, Peter D. Arkwright, Jean-Laurent Casanova, Helen C. Su, Alexandra F. Freeman, Nirali Shah, Dennis D. Hickstein, Stuart G. Tangye, Cindy S. Ma

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Abstract

Children with trisomy 21 (Down syndrome [DS]) have a 130-fold increased incidence of Hirschsprung disease (HSCR), a developmental defect in which the enteric nervous system (ENS) is missing from the distal bowel (i.e., distal bowel is aganglionic). Treatment for HSCR is surgical resection of aganglionic bowel, but many children have bowel problems after surgery. Postsurgical problems, such as enterocolitis and soiling, are especially common in children with DS. To determine how trisomy 21 affects ENS development, we evaluated the ENS in 2 DS mouse models, Ts65Dn and Tc1. These mice are trisomic for many chromosome 21 homologous genes, including Dscam and Dyrk1a, which are hypothesized to contribute to HSCR risk. Ts65Dn and Tc1 mice have normal ENS precursor migration at E12.5 and almost normal myenteric plexus structure as adults. However, Ts65Dn and Tc1 mice have markedly reduced submucosal plexus neuron density throughout the bowel. Surprisingly, the submucosal neuron defect in Ts65Dn mice is not due to excess Dscam or Dyrk1a, since normalizing copy number for these genes does not rescue the defect. These findings suggest the possibility that the high frequency of bowel problems in children with DS and HSCR may occur because of additional unrecognized problems with ENS structure.

Authors

Ellen M. Schill, Christina M. Wright, Alisha Jamil, Jonathan M. LaCombe, Randall J. Roper, Robert O. Heuckeroth

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Abstract

Atherosclerotic plaques feature local proliferation of leukocytes and vascular smooth muscle cells (VSMCs) and changes in cellular metabolism. Yet the relationship between glucose utilization and proliferation has been technically impossible to study directly in cells of atherosclerotic plaques in vivo. We used multi-isotope imaging mass spectrometry (MIMS), a quantitative imaging platform, to measure coincident cell division and glucose utilization at suborganelle resolution in atherosclerotic plaques. In established plaques, 65% of intimal foam cells and only 4% of medial VSMCs were labeled with 15N-thymidine after 1 week of isotope treatment. Dividing cells demonstrated heightened glucose labeling. MIMS detected 2H-glucose label in multiple subcellular compartments within foam cells, including lipid droplets, the cytosol, and chromatin. Unexpectedly, we identified an intensely focal region of 2H-label in VSMCs underlying plaques. This signal diminished in regions of aorta without atherosclerosis. In advanced plaques, 15N-thymidine and 2H-glucose labeling in foam cells and VSMCs significantly decreased. These data demonstrate marked heterogeneity in VSMC glucose metabolism that was dependent on both proliferative status and proximity of VSMCs to plaques. Furthermore, these results reveal how quantitative mass spectrometry coupled with isotope imaging can complement other methods used to study cell biology directly in the growing atherosclerotic plaque in vivo.

Authors

Christelle Guillermier, Sean P. Doherty, Adam G. Whitney, Vladimir R. Babaev, MacRae F. Linton, Matthew L. Steinhauser, Jonathan D. Brown

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Abstract

BACKGROUND Recessive dystrophic epidermolysis bullosa (RDEB) is a severe form of skin fragility disorder due to mutations in COL7A1 encoding basement membrane type VII collagen (C7), the main constituent of anchoring fibrils (AFs) in skin. We developed a self-inactivating lentiviral platform encoding a codon-optimized COL7A1 cDNA under the control of a human phosphoglycerate kinase promoter for phase I evaluation.METHODS In this single-center, open-label phase I trial, 4 adults with RDEB each received 3 intradermal injections (~1 × 106 cells/cm2 of intact skin) of COL7A1-modified autologous fibroblasts and were followed up for 12 months. The primary outcome was safety, including autoimmune reactions against recombinant C7. Secondary outcomes included C7 expression, AF morphology, and presence of transgene in the injected skin.RESULTS Gene-modified fibroblasts were well tolerated, without serious adverse reactions or autoimmune reactions against recombinant C7. Regarding efficacy, there was a significant (P < 0.05) 1.26-fold to 26.10-fold increase in C7 mean fluorescence intensity in the injected skin compared with noninjected skin in 3 of 4 subjects, with a sustained increase up to 12 months in 2 of 4 subjects. The presence of transgene (codon-optimized COL7A1 cDNA) was demonstrated in the injected skin at month 12 in 1 subject, but no new mature AFs were detected.CONCLUSION To our knowledge, this is the first human study demonstrating safety and potential efficacy of lentiviral fibroblast gene therapy with the presence of COL7A1 transgene and subsequent C7 restoration in vivo in treated skin at 1 year after gene therapy. These data provide a rationale for phase II studies for further clinical evaluation.TRIAL REGISTRATION ClincalTrials.gov NCT02493816.FUNDING Cure EB, Dystrophic Epidermolysis Bullosa Research Association (UK), UK NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, and Fondation René Touraine Short-Exchange Award.

Authors

Su M. Lwin, Farhatullah Syed, Wei-Li Di, Tendai Kadiyirire, Lu Liu, Alyson Guy, Anastasia Petrova, Alya Abdul-Wahab, Fiona Reid, Rachel Phillips, Maria Elstad, Christos Georgiadis, Sophia Aristodemou, Patricia A. Lovell, James R. McMillan, John Mee, Snaigune Miskinyte, Matthias Titeux, Linda Ozoemena, Rashida Pramanik, Sonia Serrano, Racheal Rowles, Clarisse Maurin, Elizabeth Orrin, Magdalena Martinez-Queipo, Ellie Rashidghamat, Christos Tziotzios, Alexandros Onoufriadis, Mei Chen, Lucas Chan, Farzin Farzaneh, Marcela Del Rio, Jakub Tolar, Johann W. Bauer, Fernando Larcher, Michael N. Antoniou, Alain Hovnanian, Adrian J. Thrasher, Jemima E. Mellerio, Waseem Qasim, John A. McGrath

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Abstract

Despite the accepted notion that granulocytes play a universally destructive role in organ and tissue grafts, it has been recently described that eosinophils can facilitate immunosuppression-mediated acceptance of murine lung allografts. The mechanism of eosinophil-mediated tolerance, or their role in regulating alloimmune responses in the absence of immunosuppression, remains unknown. Using lung transplants in a fully MHC-mismatched BALB/c (H2d) to C57BL/6 (H2b) strain combination, we demonstrate that eosinophils downregulate T cell–mediated immune responses and play a tolerogenic role even in the absence of immunosuppression. We further show that such downregulation depends on PD-L1/PD-1–mediated synapse formation between eosinophils and T cells. We also demonstrate that eosinophils suppress T lymphocyte responses through the inhibition of T cell receptor/CD3 (TCR/CD3) subunit association and signal transduction in an inducible NOS–dependent manner. Increasing local eosinophil concentration, through administration of intratracheal eotaxin and IL-5, can ameliorate alloimmune responses in the lung allograft. Thus, our data indicate that eosinophil mobilization may be utilized as a novel means of lung allograft–specific immunosuppression.

Authors

Oscar Okwudiri Onyema, Yizhan Guo, Bayan Mahgoub, Qing Wang, Amir Manafi, Zhongcheng Mei, Anirban Banerjee, Dongge Li, Mark H. Stoler, Melissa T. Zaidi, Adam G. Schrum, Daniel Kreisel, Andrew E. Gelman, Elizabeth A. Jacobsen, Alexander Sasha Krupnick

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Abstract

Commonly available clinical parameters fail to predict early acute cellular rejection (EAR, occurring within 6 months after transplant), a major risk factor for graft loss after kidney transplantation. We performed whole-blood RNA sequencing at the time of transplant in 235 kidney transplant recipients enrolled in a prospective cohort study (Genomics of Chronic Allograft Rejection [GoCAR]) and evaluated the relationship of pretransplant transcriptomic profiles with EAR. EAR was associated with downregulation of NK and CD8+ T cell gene signatures in pretransplant blood. We identified a 23-gene set that predicted EAR in the discovery (n = 81, and AUC = 0.80) and validation (n = 74, and AUC = 0.74) sets. Exclusion of recipients with 5 or 6 HLA donor mismatches increased the AUC to 0.89. The risk score derived from the gene set was also significantly associated with acute cellular rejection after 6 months, antibody-mediated rejection and/or de novo donor-specific antibodies, and graft loss in a cohort of 154 patients, combining the validation set and additional GoCAR patients with surveillance biopsies between 6 and 24 months (n = 80) posttransplant. This 23-gene set is a potentially important new tool for determination of the recipient’s immunological risk before kidney transplantation, and facilitation of an individualized approach to immunosuppressive therapy.

Authors

Weijia Zhang, Zhengzi Yi, Chengguo Wei, Karen L. Keung, Zeguo Sun, Caixia Xi, Christopher Woytovich, Samira Farouk, Lorenzo Gallon, Madhav C. Menon, Ciara Magee, Nader Najafian, Milagros D. Samaniego, Arjang Djamali, Stephen I. Alexander, Ivy A. Rosales, Rex Neal Smith, Philip J. O’Connell, Robert Colvin, Paolo Cravedi, Barbara Murphy

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Abstract

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is caused by a single point mutation in the cardiac type 2 ryanodine receptor (RyR2). Using a knockin (KI) mouse model (R2474S/+), we previously reported that a single point mutation within the RyR2 sensitizes the channel to agonists, primarily mediated by defective interdomain interaction within the RyR2 and subsequent dissociation of calmodulin (CaM) from the RyR2. Here, we examined whether CPVT can be genetically rescued by enhancing the binding affinity of CaM to the RyR2. We first determined whether there is a possible amino acid substitution within the CaM-binding domain in the RyR2 (3584–3603 residues) that can enhance its binding affinity to CaM and found that V3599K substitution showed the highest binding affinity of CaM to the CaM-binding domain. Hence, we generated a heterozygous KI mouse model (V3599K/+) with a single amino acid substitution in the CaM-binding domain of the RyR2 and crossbred it with the heterozygous CPVT-associated R2474S/+-KI mouse to obtain a double-heterozygous R2474S/V3599K-KI mouse model. The CPVT phenotypes — bidirectional or polymorphic ventricular tachycardia, spontaneous Ca2+ transients, and Ca2+ sparks — were all inhibited in the R2474S/V3599K mice. Thus, enhancement of the CaM-binding affinity of the RyR2 is essential to prevent CPVT-associated arrhythmogenesis.

Authors

Yoshihide Nakamura, Takeshi Yamamoto, Shigeki Kobayashi, Masaki Tamitani, Yoriomi Hamada, Go Fukui, Xiaojuan Xu, Shigehiko Nishimura, Takayoshi Kato, Hitoshi Uchinoumi, Tetsuro Oda, Shinichi Okuda, Masafumi Yano

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Abstract

Background: There is growing evidence to suggest that the brain is an important target for insulin action, and that states of insulin resistance may extend to the CNS with detrimental effects on cognitive functioning. Although the effect of systemic insulin resistance on peripheral organs is well-studied, the degree to which insulin impacts brain function in vivo remains unclear. Methods: This randomized, single-blinded, 2-way-crossover, sham-controlled, pilot study determined the effects of hyperinsulinemia on fMRI brain activation during a 2-back working memory task in 9 healthy older adults (aged 57-79 years). Each participant underwent two clamp procedures (an insulin infusion and a saline placebo infusion, with normoglycemia maintained during both conditions), to examine the effects of hyperinsulinemia on task performance and associated blood-oxygen-level dependent (BOLD) signal using fMRI. Results: Hyperinsulinemia (compared to saline control) was associated with an increase in both the spatial extent and relative strength of task-related BOLD signal during the 2-back task. Further, the degree of increased task-related activation in select brain regions correlated with greater systemic insulin sensitivity, as well as decreased reaction times and performance accuracy between experimental conditions. Conclusion: Together, these findings provide evidence of insulin action in the CNS among older adults during periods of sustained cognitive demand, with the greatest effects noted for individuals with highest systemic insulin sensitivity. Funding: This work was funded by the National Institutes of Health (5R21AG051958, 2016).

Authors

Victoria J. Williams, Bianca A. Trombetta, Rabab Z. Jafri, Aaron M. Koenig, Chase D. Wennick, Becky C. Carlyle, Laya Ekhlaspour, Rexford S. Ahima, Steven J. Russell, David H. Salat, Steven E. Arnold

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Abstract

Heterozygous missense mutations in lysyl oxidase (LOX) are associated with thoracic aortic aneurysms and dissections. To assess how LOX mutations modify protein function and lead to aortic disease, we studied the factors that influence the onset and progression of vascular aneurysms in mice bearing a Lox mutation (p.M292R) linked to aortic dilation in humans. We show that mice heterozygous for the M292R mutation did not develop aneurysmal disease unless challenged with increased hemodynamic stress. Vessel dilation was confined to the ascending aorta although both the ascending and descending aortae showed changes in vessel wall structure, smooth muscle cell number and inflammatory cell recruitment that differed between wild-type and mutant animals. Studies with isolated cells found that M292R-mutant Lox is retained in the endoplasmic reticulum and ultimately cleared through an autophagy/proteasome pathway. Because the mutant protein does not transit to the Golgi where copper incorporation occurs, the protein is never catalytically active. These studies show that the M292R mutation results in LOX loss-of-function due to a secretion defect that predisposes the ascending aorta in mice (and by extension humans with similar mutations) to arterial dilation when exposed to risk factors that impart stress to the arterial wall.

Authors

Vivian S. Lee, Carmen M. Halabi, Thomas J. Broekelmann, Philip C. Trackman, Nathan O. Stitziel, Robert P. Mecham

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Abstract

The lung is a relatively quiescent organ during homeostasis, but has a remarkable capacity for repair after injury. Alveolar epithelial type I cells (AEC1s) line airspaces and mediate gas exchange. After injury, they are regenerated by differentiation from their progenitors — alveolar epithelial type II cells (AEC2s) — which also secrete surfactant to maintain surface tension and alveolar patency. While recent studies showed that the maintenance of AEC2 stemness is Wnt dependent, the molecular mechanisms underlying AEC2-AEC1 differentiation in adult lung repair are still incompletely understood. Here we show that WWTR1 (TAZ) plays a crucial role in AEC differentiation. Using an in vitro organoid culture system, we found that tankyrase inhibition can efficiently block AEC2-AEC1 differentiation, and this effect was due to the inhibition of TAZ. In a bleomycin induced lung injury model, conditional deletion of TAZ in AEC2s dramatically reduced AEC1 regeneration during recovery, leading to exacerbated alveolar lesions and fibrosis. In patients with idiopathic pulmonary fibrosis (IPF), decreased blood levels of RAGE, a biomarker of AEC1 health, were associated with more rapid disease progression. Our findings implicate TAZ as a critical factor involved in AEC2 to AEC1 differentiation, and hence the maintenance of alveolar integrity after injury.

Authors

Tianhe Sun, Zhiyu Huang, Hua Zhang, Clara Posner, Guiquan Jia, Thirumalai R. Ramalingam, Min Xu, Hans D. Brightbill, Jackson G. Egen, Anwesha Dey, Joseph R. Arron

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Abstract

Non-integrative AAV-mediated gene therapy in the liver is effective in adult patients, but faces limitations in pediatric settings due to episomal DNA loss during hepatocyte proliferation. Gene targeting is a promising approach by permanently modifying the genome. We previously rescued neonatal lethality in Crigler-Najjar mice by inserting a promoterless human uridine glucuronosyl transferase A1 (UGT1A1) cDNA in exon 14 of the albumin gene, without the use of nucleases. To increase recombination rate and therapeutic efficacy, here we used CRISPR/SaCas9. Neonatal mice were transduced with two AAVs: one expressing the SaCas9 and sgRNA, and one containing a promoterless cDNA flanked by albumin homology regions. Targeting efficiency increased ~26-fold with an eGFP reporter cDNA, reaching up to 24% of eGFP-positive hepatocytes. Next, we fully corrected the diseased phenotype of Crigler-Najjar mice by targeting the hUGT1A1 cDNA. Treated mice had normal plasma bilirubin up to 10 months after administration, hUGT1A1 protein levels were ~6-fold higher than in WT liver, with a 90-fold increase in recombination rate. Liver histology, inflammatory markers, and plasma albumin were normal in treated mice, with no off-targets in predicted sites. Thus, the improved efficacy and reassuring safety profile support the potential application of the proposed approach to other liver diseases.

Authors

Alessia De Caneva, Fabiola Porro, Giulia Bortolussi, Riccardo Sola, Michela Lisjak, Adi Barzel, Mauro Giacca, Mark A. Kay, Kristian Vlahoviček, Lorena Zentilin, Andrés F. Muro

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Abstract

Genetic susceptibility to chronic pancreatitis in humans is frequently associated with mutations that increase activation of the digestive protease trypsin. Intrapancreatic trypsin activation is an early event in experimental acute pancreatitis in rodents, suggesting that trypsin is a key driver of pathology. In contrast to trypsin, the pancreatic protease chymotrypsin serves a protective function by mitigating trypsin activation through degradation. In humans, loss-of-function mutations in chymotrypsin C (CTRC) are common risk factors for chronic pancreatitis; however, the pathogenic effect of CTRC deficiency has not been corroborated in animal models yet. Here we report that C57BL/6 mice that are widely used for genetic manipulations do not express functional CTRC due to a single-nucleotide deletion in exon 2 of the Ctrc gene. We restored a functional Ctrc locus in C57BL/6N mice and demonstrated that in the novel Ctrc+ strain the severity of cerulein-induced experimental acute and chronic pancreatitis was significantly ameliorated. Improved disease parameters were associated with reduced intrapancreatic trypsin activation suggesting a causal link between CTRC-mediated trypsinogen degradation and protection against pancreatitis. Taken together with prior human genetic and biochemical studies, the observations provide conclusive evidence for the protective role of CTRC against pancreatitis.

Authors

Andrea Geisz, Zsanett Jancsó, Balázs Csaba Németh, Eszter Hegyi, Miklós Sahin-Tóth

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