Contractile and hemodynamic forces coordinate Notch1b-mediated outflow tract valve formation

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Abstract

Biomechanical forces and endothelial-to-mesenchymal transition (EndoMT) are known to mediate valvulogenesis. However, the relative contributions of myocardial contractile and hemodynamic shear forces remain poorly understood. We integrated 4-D light-sheet imaging of transgenic zebrafish models with moving-domain computational fluid dynamics to determine effects of changes in contractile forces and fluid wall shear stress (WSS) on ventriculobulbar (VB) valve development. Augmentation of myocardial contractility with isoproterenol increased both WSS and Notch1b activity in the developing outflow tract (OFT) and resulted in VB valve hyperplasia. Increasing WSS in the OFT, achieved by increasing blood viscosity through EPO mRNA injection, also resulted in VB valve hyperplasia. Conversely, decreasing myocardial contractility by Tnnt2a morpholino oligonucleotide (MO) administration, 2,3-butanedione monoxime treatment, or Plcγ1 inhibition completely blocked VB valve formation, which could not be rescued by increasing WSS or activating Notch. Decreasing WSS in the OFT, achieved by slowing heart rate with metoprolol or reducing viscosity with Gata1a MO, did not affect VB valve formation. Immunofluorescent staining with the mesenchymal marker, DM-GRASP, revealed that biomechanical force-mediated Notch1b activity is implicated in EndoMT to modulate valve morphology. Altogether, increases in WSS result in Notch1b- EndoMT-mediated VB valve hyperplasia, whereas decreases in contractility result in reduced Notch1b activity, absence of EndoMT, and VB valve underdevelopment. Thus, we provide developmental mechanotransduction mechanisms underlying Notch1b-mediated EndoMT in the OFT.

Authors

Jeffrey J. Hsu, Vijay Vedula, Kyung In Baek, Cynthia Chen, Junjie Chen, Man In Chou, Jeffrey Lam, Shivani Subhedar, Jennifer Wang, Yichen Ding, Chih-Chiang Chang, Juhyun Lee, Linda L. Demer, Yin Tintut, Alison L. Marsden, Tzung K. Hsiai

Detection of circulating extracellular mRNAs by modified small-RNA-sequencing analysis

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Abstract

Extracellular mRNAs (ex-mRNAs) potentially supersede extracellular miRNAs (ex-miRNAs) and other RNA classes as biomarkers. We performed conventional small-RNA-sequencing (sRNA-seq) and sRNA-seq with T4 polynucleotide kinase (PNK) end-treatment of total exRNA isolated from serum and platelet-poor EDTA, ACD, and heparin plasma to study the effect on ex-mRNA capture. Compared to conventional sRNA-seq PNK-treatment increased the detection of informative ex-mRNAs reads up to 50-fold. The exRNA pool was dominated by hematopoietic cells and platelets, with additional contribution from the liver. About 60% of the 15- to 42-nt reads originated from the coding sequences, in a pattern reminiscent of ribosome-profiling. Blood sample type had a considerable influence on the exRNA profile. On average approximately 350 to 1,100 distinct ex-mRNA transcripts were detected depending on plasma type. In serum, additional transcripts from neutrophils and hematopoietic cells increased this number to near 2,300. EDTA and ACD plasma showed a destabilizing effect on ex mRNA and non-coding RNA ribonucleoprotein complexes compared to other plasma types. In a proof-of-concept study, we investigated differences between the exRNA profiles of patients with acute coronary syndrome (ACS) and healthy controls. The improved tissue resolution of ex mRNAs after PNK-treatment enabled us to detect a neutrophil-signature in ACS that escaped detection by ex miRNA analysis.

Authors

Kemal M. Akat, Youngmin A. Lee, Arlene Hurley, Pavel Morozov, Klaas E.A. Max, Miguel Brown, Kimberly Bogardus, Anuoluwapo Sopeyin, Kai Hildner, Thomas G. Diacovo, Markus F. Neurath, Martin Borggrefe, Thomas Tuschl

Sclerostin inhibition alleviates breast cancer–induced bone metastases and muscle weakness

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Abstract

Breast cancer bone metastases often cause a debilitating non-curable condition with osteolytic lesions, muscle weakness and a high mortality. Current treatment comprises chemotherapy, irradiation, surgery and anti-resorptive drugs that restrict but do not revert bone destruction. In metastatic breast cancer cells, we determined the expression of sclerostin, a soluble Wnt inhibitor that represses osteoblast differentiation and bone formation. In mice with breast cancer bone metastases, pharmacological inhibition of sclerostin using an anti-sclerostin antibody (Scl-Ab) reduced metastases without tumor cell dissemination to other distant sites. Sclerostin inhibition prevented the cancer-induced bone destruction by augmenting osteoblast-mediated bone formation and reducing osteoclast-dependent bone resorption. During advanced disease, NF-κB and p38 signaling was increased in muscles in a TGF-β1-dependent manner, causing muscle fiber atrophy, muscle weakness and tissue regeneration with an increase in Pax7-positive satellite cells. Scl-Ab treatment restored NF-κB and p38 signaling, the abundance of Pax7-positive cells and ultimately muscle function. These effects improved the overall health condition and expanded the life span of cancer-bearing mice. Together, these results demonstrate that pharmacological inhibition of sclerostin reduces bone metastatic burden and muscle weakness with a prolongation of the survival time. This might provide novel options for treating musculoskeletal complications in breast cancer patients.

Authors

Eric Hesse, Saskia Schröder, Diana Brandt, Jenny Pamperin, Hiroaki Saito, Hanna Taipaleenmäki

B lymphocytes protect islet β cells in diabetes prone NOD mice treated with imatinib

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Abstract

Imatinib (Gleevec) reverses type 1 diabetes (T1D) in NOD mice and is currently in clinical trials in individuals with recent-onset disease. While research has demonstrated that imatinib protects islet β cells from the harmful effects of ER stress, the role the immune system plays in its reversal of T1D has been less well understood, and specific cellular immune targets have not been identified. In this study, we demonstrate that B lymphocytes, an immune subset that normally drives diabetes pathology, are unexpectedly required for reversal of hyperglycemia in NOD mice treated with imatinib. In the presence of B lymphocytes, reversal was linked to an increase in serum insulin concentration, but not an increase in islet β cell mass or proliferation. However, improved β cell function was reflected by a partial recovery of MafA transcription factor expression, a sensitive marker of islet β cell stress that is important to adult β cell function. Imatinib treatment was found to increase the antioxidant capacity of B lymphocytes, improving reactive oxygen species (ROS) handling in NOD islets. This study reveals a novel mechanism through which imatinib enables B lymphocytes to orchestrate functional recovery of T1D β cells.

Authors

Christopher S. Wilson, Jason M. Spaeth, Jay Karp, Blair T. Stocks, Emilee M. Hoopes, Roland W. Stein, Daniel J. Moore

ERK1/2 signaling induces skeletal muscle slow fiber-type switching and reduces muscular dystrophy disease severity

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Abstract

Mitogen-activated protein kinase (MAPK) signaling consists of an array of successively acting kinases. The extracellular signal-regulated kinases 1/2 (ERK1/2) are major components of the greater MAPK cascade that transduce growth factor signaling at the cell membrane. Here we investigated ERK1/2 signaling in skeletal muscle homeostasis and disease. Using mouse genetics, we observed that the muscle-specific expression of a constitutively active MEK1 mutant promotes greater ERK1/2 signaling that mediates fiber-type switching to a slow, oxidative phenotype with type I myosin heavy chain expression. Using a conditional and temporally regulated Cre strategy as well as Mapk1 (ERK2) and Mapk3 (ERK1) genetically targeted mice, MEK1-ERK2 signaling was shown to underlie this fast-to-slow fiber type switching in adult skeletal muscle as well as during development. Physiologic assessment of these activated MEK1-ERK1/2 mice showed enhanced metabolic activity and oxygen consumption with greater muscle fatigue resistance. Moreover, induction of MEK1-ERK1/2 signaling increased dystrophin and utrophin protein expression in a mouse model of limb-girdle muscle dystrophy and protected myofibers from damage. In summary, sustained MEK1-ERK1/2 activity in skeletal muscle produces a fast-to-slow fiber-type switch that protects from muscular dystrophy, suggesting a therapeutic approach to enhance the metabolic effectiveness of muscle and protect from dystrophic disease.

Authors

Justin G. Boyer, Vikram Prasad, Taejeong Song, Donghoon Lee, Xing Fu, Kelly M. Grimes, Michelle A. Sargent, Sakthivel Sadayappan, Jeffery D. Molkentin

Alteration of myocardial GRK2 produces a global metabolic phenotype

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Abstract

A vast body of literature has established GRK2 as a key player in the development and progression of heart failure. Inhibition of GRK2 improves cardiac function post injury in numerous animal models. In recent years, discovery of several non-canonical GRK2 targets has expanded our view of this kinase. Here, we describe the novel and exciting finding that cardiac GRK2 activity can regulate whole body metabolism. Transgenic mice with cardiac-specific expression of a peptide inhibitor of GRK2 (TgβARKct) display an enhanced obesogenic phenotype when fed a high fat diet (HFD). In contrast, mice with cardiac-specific overexpression of GRK2 (TgGRK2) show resistance to HFD induced obesity. White adipose tissue (WAT) mass was significantly enhanced in HFD fed TgβARKct mice. Furthermore, regulators of adipose differentiation were differentially regulated in WAT from mice with gain or loss of GRK2 function. Using complex metabolomics we found that cardiac GRK2 signaling altered myocardial BCAA and endocannabinoid metabolism and modulated circulating BCAA and endocannabinoid metabolite profiles on a HFD, and one of the BCAA metabolites identified here enhances adipocyte differentiation in vitro. Taken together, these results suggest that metabolic changes in the heart due to GRK2 signaling on a HFD control whole body metabolism.

Authors

Benjamin P. Woodall, Kenneth S. Gresham, Meryl A. Woodall, Mesele-Christina Valenti, Alessandro Cannavo, Jessica Pfleger, J. Kurt Chuprun, Konstantinos Drosatos, Walter J. Koch

Safety and tolerability of conditioning chemotherapy followed by CD19-targeted CAR T cells for relapsed/refractory CLL

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Abstract

BACKGROUND. Subgroups of patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) exhibit suboptimal outcomes after standard therapies, including oral kinase inhibitors. We and others have previously reported on safety and efficacy of autologous CD19-targeted CAR T-cells for these patients; here we report safety and long-term follow-up of CAR T-cell therapy with or without conditioning chemotherapy for patients with R/R CLL and indolent B-cell non-Hodgkin lymphoma (B-NHL). METHODS. We conducted a phase 1 clinical trial investigating CD19-targeted CAR T-cells incorporating a CD28 costimulatory domain (19-28z). Seventeen of 20 patients received conditioning chemotherapy prior to CAR T-cell infusion. Five patients with CLL received ibrutinib at the time of autologous T-cell collection and/or CAR T-cell administration. RESULTS. This analysis included 16 patients with R/R CLL and 4 patients with R/R indolent B-NHL. Cytokine release syndrome (CRS) was observed in all 20 patients but grades 3 and 4 CRS and neurological events were uncommon (10% for each). Ex vivo expansion of T-cells and proportions of CD4+/CD8+ CAR T-cells with CD62L+CD127+ immunophenotype were significantly greater in patients on ibrutinib at leukapheresis. Three of 12 evaluable CLL patients receiving conditioning chemotherapy achieved CR (two had minimal residual disease–negative CR). All patients achieving CR remained progression-free at median follow-up of 53 months. CONCLUSION. Conditioning chemotherapy and 19-28z CAR T-cells were acceptably tolerated across investigated dose levels in heavily pretreated patients with R/R CLL and indolent B-NHL, and a subgroup of patients achieved durable CR. Ibrutinib therapy may modulate autologous T-cell phenotype. TRIAL REGISTRATION. ClinicalTrials.gov NCT00466531. FUNDING. Juno Therapeutics.

Authors

Mark B. Geyer, Isabelle Rivière, Brigitte Sénéchal, Xiuyan Wang, Yongzeng Wang, Terence J. Purdon, Meier Hsu, Sean M. Devlin, M. Lia Palomba, Elizabeth Halton, Yvette Bernal, Michel Sadelain, Jae H. Park, Renier J. Brentjens

Axl-mediated activation of TBK1 drives epithelial plasticity in pancreatic cancer

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Abstract

Pancreatic ductal adenocarcinoma (PDA) is characterized by an activating mutation in KRAS. Direct inhibition of KRAS through pharmacological means remains a challenge; however, targeting key KRAS effectors has therapeutic potential. We investigated the contribution of TANK-binding kinase 1 (TBK1), a critical downstream effector of mutant active KRAS, to PDA progression. We report that TBK1 supports the growth and metastasis of KRAS-mutant PDA by driving an epithelial plasticity program in tumor cells that enhances invasive and metastatic capacity. Further, we identify that the receptor tyrosine kinase Axl induces TBK1 activity in a Ras-RalB-dependent manner. These findings demonstrate that TBK1 is central to an Axl-driven epithelial-mesenchymal transition in KRAS-mutant PDA and suggest that interruption of the Axl-TBK1 signaling cascade above or below KRAS has potential therapeutic efficacy in this recalcitrant disease.

Authors

Victoria H. Cruz, Emily N. Arner, Wenting Du, Alberto E. Bremauntz, Rolf A. Brekken

VIPergic neurons of the infralimbic and prelimbic cortices control palatable food intake through separate cognitive pathways

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Abstract

The prefrontal cortex controls food reward seeking and ingestion, playing important roles in directing attention, regulating motivation towards reward pursuit, and the assignment of reward salience and value. The cell types that mediate these behavioral functions, however, are not well described. We report here that optogenetic activation of vasoactive peptide expressing (VIP) interneurons in both the infralimbic (IL) and prelimbic (PL) divisions of the medial prefrontal cortex in mice is sufficient to reduce acute, binge-like intake of high calorie palatable food in the absence of any effect on low calorie rodent chow intake in the sated animal. In addition, we discovered that the behavioral mechanisms associated with these changes in feeding differed between animals that underwent either IL or PL VIPergic stimulation. While IL VIP neurons showed the ability to reduce palatable food intake, this effect was dependent upon the novelty and relative value of the food source. In addition, IL VIP neuron activation significantly reduced novel object- and novel social investigative behavior. Activation of PL VIP neurons, however, produced a reduction in high calorie palatable food intake that was independent of food novelty. Neither IL nor PL VIP excitation changed motivation to obtain food reward. Our data show how neurochemically-defined populations of cortical interneurons can regulate specific aspects of food reward-driven behavior, resulting in a selective reduction in intake of highly valued food.

Authors

Brandon A. Newmyer, Ciarra M. Whindleton, Peter M. Klein, Mark P. Beenhakker, Marieke K. Jones, Michael M. Scott

Deficiency of Socs3 leads to brain-targeted EAE via enhanced neutrophil activation and ROS production

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Abstract

Dysregulation of the JAK/STAT signaling pathway is associated with Multiple Sclerosis (MS) and its mouse model, Experimental Autoimmune Encephalomyelitis (EAE). Suppressors Of Cytokine Signaling (SOCS) negatively regulate the JAK/STAT pathway. We previously reported a severe, brain-targeted, atypical form of EAE in mice lacking Socs3 in myeloid cells (Socs3ΔLysM), which is associated with cerebellar neutrophil infiltration. There is emerging evidence that neutrophils are detrimental in the pathology of MS/EAE, however, their exact function is unclear. Here we demonstrate that neutrophils from the cerebellum of Socs3ΔLysM mice show a hyper-activated phenotype with excessive production of reactive oxygen species (ROS) at the peak of EAE. Neutralization of ROS in vivo delayed the onset and reduced severity of atypical EAE. Mechanistically, Socs3-deficient neutrophils exhibit enhanced STAT3 activation, a hyper-activated phenotype in response to G-CSF, and upon G-CSF priming, increased ROS production. Neutralization of G-CSF in vivo significantly reduced the incidence and severity of the atypical EAE phenotype. Overall, our work elucidates that hypersensitivity of G-CSF/STAT3 signaling in Socs3ΔLysM mice leads to atypical EAE by enhanced neutrophil activation and increased oxidative stress, which may explain the detrimental role of G-CSF in MS patients.

Authors

Zhaoqi Yan, Wei Yang, Luke Parkitny, Sara A. Gibson, Kevin S. Lee, Forrest Collins, Jessy S. Deshane, Wayne Cheng, Amy S. Weinmann, Hairong Wei, Hongwei Qin, Etty N. Benveniste