Latest issue: February 13, 2020

In the issue

Abstract

A terminally differentiated cellular phenotype is thought to be maintained, at least in part, by both active and repressive histone marks. However, it is unclear whether regenerating cells after injury need to replicate such epigenetic marks to recover. To test whether renal epithelial cell regeneration is dependent on histone H3K4 methylation, we generated a mouse model that deleted the Paxip1 gene in mature renal proximal tubules. Paxip1 encodes PTIP, an essential protein in the Mll3/4 histone H3K4 methyltransferase complex. Mice with PTIP deletions in the adult kidney proximal tubules were viable and fertile. Upon acute kidney injury, such mice failed to regenerate damaged tubules, leading to scarring and interstitial fibrosis. The inability to repair damage was likely due to a failure to reenter mitosis and reactivate regulatory genes such as Sox9. PTIP deletion reduced histone H3K4 methylation in uninjured adult kidneys but did not significantly affect function or the expression of epithelial specific markers. Strikingly, cell lineage tracing revealed that surviving PTIP mutant cells could alter their phenotype and lose epithelial markers. These data demonstrate that PTIP and associated MLL3/4-mediated histone methylation are needed for regenerating proximal tubules and to maintain or reestablish the cellular epithelial phenotype.

Authors

Abdul Soofi, Ana P. Kutschat, Mohammad Azam, Ann M. Laszczyk, Gregory R. Dressler

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Abstract

BACKGROUND The circadian system entrains behavioral and physiological rhythms to environmental cycles, and modern lifestyles disrupt this entrainment. We investigated a timed exercise intervention to phase shift the internal circadian rhythm.METHODS In 52 young, sedentary adults, dim light melatonin onset (DLMO) was measured before and after 5 days of morning (10 hours after DLMO; n = 26) or evening (20 hours after DLMO; n = 26) exercise. Phase shifts were calculated as the difference in DLMO before and after exercise.RESULTS Morning exercise induced phase advance shifts (0.62 ± 0.18 hours) that were significantly greater than phase shifts from evening exercise (–0.02 ± 0.18 hours; P = 0.01). Chronotype also influenced the effect of timed exercise. For later chronotypes, both morning and evening exercise induced phase advances (0.54 ± 0.29 hours and 0.46 ±0.25 hours, respectively). In contrast, earlier chronotypes had phase advances from morning exercise (0.49 ± 0.25 hours) but had phase delays from evening exercise (–0.41 ± 0.29 hours).CONCLUSION Late chronotypes — those who experience the most severe circadian misalignment — may benefit from phase advances induced by exercise in the morning or evening, but evening exercise may exacerbate circadian misalignment in early chronotypes. Thus, personalized exercise timing prescription, based on chronotype, could alleviate circadian misalignment in young adults.TRIAL REGISTRATION Trial registration can be found at www.clinicaltrials.gov (NCT04097886).FUNDING Funding was supplied by NIH grants UL1TR001998 and TL1TR001997, the Barnstable Brown Diabetes and Obesity Center, the Pediatric Exercise Physiology Laboratory Endowment, the Arvle and Ellen Turner Thacker Research Fund, and the University of Kentucky.

Authors

J. Matthew Thomas, Philip A. Kern, Heather M. Bush, Kristen J. McQuerry, W. Scott Black, Jody L. Clasey, Julie S. Pendergast

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Abstract

Dengue virus (DENV) and Zika virus (ZIKV) are closely related mosquito-borne flaviviruses that co-circulate in tropical regions and constitute major threats to global human health. Whether preexisting immunity to one virus affects disease caused by the other during primary or secondary infections is unknown but is critical in preparing for future outbreaks and predicting vaccine safety. Using a human skin explant model, we show that DENV-3 immune sera increased recruitment and infection of Langerhans cells, macrophages, and dermal dendritic cells following inoculation with DENV-2 or ZIKV. Similarly, ZIKV immune sera enhanced infection with DENV-2. Immune sera increased migration of infected Langerhans cells to the dermis and emigration of infected cells out of skin. Heterotypic immune sera increased viral RNA in the dermis almost 10-fold and reduced the amount of virus required to infect a majority of myeloid cells by 100- to 1000-fold. Enhancement was associated with cross-reactive IgG and induction of IL-10 expression and was mediated by both CD32 and CD64 Fcγ receptors. These findings reveal that preexisting heterotypic immunity greatly enhances DENV and ZIKV infection, replication, and spread in human skin. This relevant tissue model will be valuable in assessing the efficacy and risk of dengue and Zika vaccines in humans.

Authors

Priscila M. S. Castanha, Geza Erdos, Simon C. Watkins, Louis D. Falo Jr., Ernesto T. A. Marques, Simon M. Barratt-Boyes

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Abstract

Idiopathic inflammatory myopathies (IIM) are characterized by muscle inflammation and weakness, myositis-specific autoantibodies (MSAs), and extramuscular organ damage. The role of neutrophil dysregulation and neutrophil extracellular traps (NETs) in IIM is unclear. We assessed whether pathogenic neutrophil subsets (low-density granulocytes [LDGs]) and NETs were elevated in IIM, associated with clinical presentation and MSAs, and their effect on skeletal myoblasts and myotubes. Circulating NETs and LDGs were quantified and correlated with clinical measures. Specific MSAs were tested for their ability to induce NETs. NETs and neutrophil gene expression were measured in IIM biopsies. Whether NETs damage skeletal myoblasts and myotubes was tested. Circulating LDGs and NETs were increased in IIM. IIM LDGs had an enhanced ability to form NETs. LDGs and NETs correlated with IIM disease activity and muscle damage. The serum MSA anti-MDA5 correlated with circulating and tissue NETs and directly enhanced NET formation. An enhanced neutrophil gene signature was present in IIM muscle and associated with muscle injury and tissue IFN gene signatures. IIM NETs decreased the viability of myotubes in a citrullinated histone-dependent manner. Dysregulated neutrophil pathways may play pathogenic roles in IIM through their ability to directly injure muscle cells and other affected tissues.

Authors

Nickie Seto, Jose Jiram Torres-Ruiz, Carmelo Carmona-Rivera, Iago Pinal-Fernandez, Katherine Pak, Monica M. Purmalek, Yuji Hosono, Catia Fernandes-Cerqueira, Prateek Gowda, Nathan Arnett, Alexander Gorbach, Olivier Benveniste, Diana Gómez-Martín, Albert Selva-O’Callaghan, José C. Milisenda, Josep M. Grau-Junyent, Lisa Christopher-Stine, Frederick W. Miller, Ingrid E. Lundberg, J. Michelle Kahlenberg, Adam I. Schiffenbauer, Andrew Mammen, Lisa G. Rider, Mariana J. Kaplan

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Abstract

Interleukin-3 (IL-3) receptor α (IL-3Rα) is the α subunit of the ligand-specific IL-3R and initiates intracellular signaling in response to IL-3. IL-3 amplifies proinflammatory signaling and cytokine storm in murine sepsis models. Here we found that RNFT2 (RING finger transmembrane-domain containing protein 2, also TMEM118), a previously uncharacterized RING finger ubiquitin E3 ligase, negatively regulated IL-3–dependent cellular responses through IL-3Rα ubiquitination and degradation in the proteasome. In vitro, IL-3 stimulation promoted IL-3Rα proteasomal degradation dependent on RNFT2, and we identified IL-3Rα lysine 357 as a ubiquitin acceptor site. We determined that LPS priming reduces RNFT2 abundance, extends IL-3Rα half-life, and sensitizes cells to the effects of IL-3, acting synergistically to increase proinflammatory signaling. In vivo, IL-3 synergized with LPS to exacerbate lung inflammation in LPS and Pseudomonas aeruginosa–challenged mice; conversely, IL-3 neutralization reduced LPS-induced lung injury. Further, RNFT2 overexpression reduced lung inflammation and injury, whereas Rnft2 knockdown exacerbated inflammatory responses in LPS-induced murine lung injury. Last, we examined RNFT2 and IL-3Rα in human lung explants from patients with cystic fibrosis and also showed that IL-3 is elevated in mechanically ventilated critically ill humans at risk for acute respiratory distress syndrome. These results identify RNFT2 as a negative regulator of IL-3Rα and show a potential role for the RNFT2/IL-3Rα/IL-3 axis in regulating innate immune responses in the lung.

Authors

Yao Tong, Travis B. Lear, John Evankovich, Yanwen Chen, James D. Londino, Michael M. Myerburg, Yingze Zhang, Iulia D. Popescu, John F. McDyer, Bryan J. McVerry, Karina C. Lockwood, Michael J. Jurczak, Yuan Liu, Bill B. Chen

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Abstract

Chronic sympathoexcitation is implicated in ventricular arrhythmogenesis (VAs) following myocardial infarction (MI), but the critical neural pathways involved are not well understood. Cardiac adrenergic function is partly regulated by sympathetic afferent reflexes, transduced by spinal afferent fibers expressing the transient receptor potential cation subfamily V member 1 (TRPV1) channel. The role of chronic TRPV1 afferent signaling in VAs is not known. We hypothesized that persistent TRPV1 afferent neurotransmission promotes VAs after MI. Using epicardial resiniferatoxin (RTX) to deplete cardiac TRPV1–expressing fibers, we dissected the role of this neural circuit in VAs after chronic MI in a porcine model. We examined the underlying mechanisms using molecular approaches, IHC, in vitro and in vivo cardiac electrophysiology, and simultaneous cardioneural mapping. Epicardial RTX depleted cardiac TRPV1 afferent fibers and abolished functional responses to TRPV1 agonists. Ventricular tachycardia/fibrillation (VT/VF) was readily inducible in MI subjects by programmed electrical stimulation or cesium chloride administration; however, TRPV1 afferent depletion prevented VT/VF induced by either method. Mechanistically, TRPV1 afferent depletion did not alter cardiomyocyte action potentials and calcium transients, the expression of ion channels, or calcium handling proteins. However, it attenuated fibrosis and mitigated electrical instability in the scar border zone. In vivo recordings of cardiovascular-related stellate ganglion neurons (SGNs) revealed that MI enhances SGN function and disrupts integrated neural processing. Depleting TRPV1 afferents normalized these processes. Taken together, these data indicate that, after MI, TRPV1 afferent–induced adrenergic dysfunction promotes fibrosis and adverse cardiac remodeling, and it worsens border zone electrical heterogeneity, resulting in electrically unstable ventricular myocardium. We propose targeting TRPV1-expressing afferent to reduce VT/VF following MI.

Authors

Koji Yoshie, Pradeep S. Rajendran, Louis Massoud, Janki Mistry, M. Amer Swid, Xiaohui Wu, Tamer Sallam, Rui Zhang, Joshua I. Goldhaber, Siamak Salavatian, Olujimi A. Ajijola

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Abstract

BACKGROUND Siponimod (BAF312) is a selective sphingosine-1-phosphate receptor 1 and 5 (S1PR1, S1PR5) modulator recently approved for active secondary progressive multiple sclerosis (SPMS). The immunomodulatory effects of siponimod in SPMS have not been previously described.METHODS We conducted a multicentered, randomized, double-blind, placebo-controlled AMS04 mechanistic study with 36 SPMS participants enrolled in the EXPAND trial. Gene expression profiles were analyzed using RNA derived from whole blood with Affymetrix Human Gene ST 2.1 microarray technology. We performed flow cytometry–based assays to analyze the immune cell composition and microarray gene expression analysis on peripheral blood from siponimod-treated participants with SPMS relative to baseline and placebo during the first-year randomization phase.RESULTS Microarray analysis showed that immune-associated genes involved in T and B cell activation and receptor signaling were largely decreased by siponimod, which is consistent with the reduction in CD4+ T cells, CD8+ T cells, and B cells. Flow cytometric analysis showed that within the remaining lymphocyte subsets there was a reduction in the frequencies of CD4+ and CD8+ naive T cells and central memory cells, while T effector memory cells, antiinflammatory Th2, and T regulatory cells (Tregs) were enriched. Transitional regulatory B cells (CD24hiCD38hi) and B1 cell subsets (CD43+CD27+) were enriched, shifting the balance in favor of regulatory B cells over memory B cells. The proregulatory shift driven by siponimod treatment included a higher proliferative potential of Tregs compared with non-Tregs, and upregulated expression of PD-1 on Tregs. Additionally, a positive correlation was found between Tregs and regulatory B cells in siponimod-treated participants.CONCLUSION The shift toward an antiinflammatory and suppressive homeostatic immune system may contribute to the clinical efficacy of siponimod in SPMS.TRIAL REGISTRATION NCT02330965.

Authors

Qi Wu, Elizabeth A. Mills, Qin Wang, Catherine A. Dowling, Caitlyn Fisher, Britany Kirch, Steven K. Lundy, David A. Fox, Yang Mao-Draayer, the AMS04 Study Group

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Abstract

Recovery from measles results in life-long protective immunity. To understand induction of long-term immunity, rhesus macaques were studied for 6 months after infection with wild-type measles virus (MeV). Infection caused viremia and rash, with clearance of infectious virus by day 14. MeV RNA persisted in PBMCs for 30–90 days and in lymphoid tissue for 6 months most often in B cells but was rarely detected in BM. Antibody with neutralizing activity and binding specificity for MeV nucleocapsid (N), hemagglutinin (H), and fusion proteins appeared with the rash and avidity matured over 3–4 months. Lymph nodes had increasing numbers of MeV-specific antibody-secreting cells (ASCs) and germinal centers with late hyalinization. ASCs appeared in circulation with the rash and continued to appear along with peripheral T follicular helper cells for the study duration. ASCs in lymph nodes and PBMCs produced antibody against both H and N, with more H-specific ASCs in BM. During days 14–21, 20- to 100-fold more total ASCs than MeV-specific ASCs appeared in circulation, suggesting mobilization of preexisting ASCs. Therefore, persistence of MeV RNA in lymphoid tissue was accompanied by continued germinal center formation, ASC production, avidity maturation, and accumulation of H-specific ASCs in BM to sustain neutralizing antibody and protective immunity.

Authors

Ashley N. Nelson, Wen-Hsuan W. Lin, Rupak Shivakoti, Nicole E. Putnam, Lisa Mangus, Robert J. Adams, Debra Hauer, Victoria K. Baxter, Diane E. Griffin

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Abstract

Alternative polyadenylation (APA) is a widespread and important mechanism in regulation of gene expression. Dysregulation of the 3′ UTR cleavage and polyadenylation represents a common characteristic among many disease states, including lung fibrosis. In this study, we investigated the role of mammalian cleavage factor I–mediated (CFIm-mediated) APA in regulating extracellular matrix production in response to mechanical stimuli from stiffened matrix simulating the fibrotic lungs. We found that stiff matrix downregulated expression of CFIm68, CFIm59 and CFIm25 subunits and promoted APA in favor of the proximal poly(A) site usage in the 3′ UTRs of type I collagen (COL1A1) and fibronectin (FN1) in primary human lung fibroblasts. Knockdown and overexpression of each individual CFIm subunit demonstrated that CFIm68 and CFIm25 are indispensable attributes of stiff matrix–induced APA and overproduction of COL1A1, whereas CFIm did not appear to mediate stiffness-regulated FN1 APA. Furthermore, expression of the CFIm subunits was associated with matrix stiffness in vivo in a bleomycin-induced mouse model of pulmonary fibrosis. These data suggest that stiff matrix instigates type I collagen biogenesis by selectively targeting mRNA transcripts for 3′ UTR shortening. The current study uncovered a potential mechanism for regulation of the CFIm complex by mechanical cues under fibrotic conditions.

Authors

Zijing Zhou, Jing Qu, Li He, Yi Zhu, Shan-Zhong Yang, Feng Zhang, Ting Guo, Hong Peng, Ping Chen, Yong Zhou

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Abstract

Current models of B lymphocyte biology posit that B cells continuously recirculate between lymphoid organs, without accumulating in peripheral healthy tissues. Nevertheless, B lymphocytes are one of the most prevalent leukocyte populations in the naive murine heart. To investigate this apparent inconsistency in the literature, we conducted a systematic analysis of myocardial B cell ontogeny, trafficking dynamics, histology, and gene expression patterns. We found that myocardial B cells represent a subpopulation of circulating B cells that make close contact with the microvascular endothelium of the heart and arrest their transit as they pass through the heart. The vast majority (>95%) of myocardial B cells remain intravascular, whereas few (<5%) myocardial B cells cross the endothelium into myocardial tissue. Analyses of mice with B cell deficiency or depletion indicated that B cells modulate the myocardial leukocyte pool composition. Analysis of B cell–deficient animals suggested that B cells modulate myocardial growth and contractility. These results transform our current understanding of B cell recirculation in the naive state and reveal a previously unknown relationship between B cells and myocardial physiology. Further work will be needed to assess the relevance of these findings to other organs.

Authors

Luigi Adamo, Cibele Rocha-Resende, Chieh-Yu Lin, Sarah Evans, Jesse Williams, Hao Dun, Wenjun Li, Cedric Mpoy, Prabhakar S. Andhey, Buck E. Rogers, Kory Lavine, Daniel Kreisel, Maxim Artyomov, Gwendalyn J. Randolph, Douglas L. Mann

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Abstract

Ultrasound-induced microbubble (USMB) cavitation is widely used to promote drug delivery. Our previous study investigated USMB targeting the round window membrane by applying the ultrasound transducer to the tympanic bulla. In the present study, we further extended the use of this technology to enhance drug delivery to the inner ear by introducing the ultrasound transducer into the external auditory canal (EAC) or applying it to the skull. Using a 3-dimensional–printed diffusion apparatus mimicking the pathway for ultrasound passing through and reaching the middle ear cavity in vitro, the models simulating the transcanal and transcranial approach demonstrated 4.8-fold– and 3.7-fold–higher delivery efficiencies, respectively. In an in vivo model of guinea pigs, by filling tympanic bulla with microbubbles and biotin-FITC, USMB applied transcanally and transcranially induced 2.8-fold and 1.5-fold increases in biotin-FITC delivery efficiencies, respectively. In addition, the gentamicin uptake by cochlear and vestibular hair cells and gentamicin-induced hair cell loss were significantly enhanced following transcanal application of USMB. On the 28th day after transcanal USMB, safety assessment showed no significant changes in the hearing thresholds and the integrity of cochlea. These are the first results to our knowledge to demonstrate the feasibility and support the potential clinical application of applying USMB via EAC to facilitate drug delivery into the inner ear.

Authors

Ai-Ho Liao, Chih-Hung Wang, Ping-Yu Weng, Yi-Chun Lin, Hao Wang, Hang-Kang Chen, Hao-Li Liu, Ho-Chiao Chuang, Cheng-Ping Shih

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Abstract

BACKGROUND Mitochondrial dysfunction, a proposed mechanism of chronic obstructive pulmonary disease (COPD) pathogenesis, is associated with the leakage of mitochondrial DNA (mtDNA), which may be detected extracellularly in various bodily fluids. Despite evidence for the increased prevalence of chronic kidney disease in COPD subjects and for mitochondrial dysfunction in the kidneys of murine COPD models, whether urine mtDNA (u-mtDNA) associates with measures of disease severity in COPD is unknown.METHODS Cell-free u-mtDNA, defined as copy number of mitochondrially encoded NADH dehydrogenase-1 (MTND1) gene, was measured by quantitative PCR and normalized to urine creatinine in cell-free urine samples from participants in the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) cohort. Urine albumin/creatinine ratios (UACR) were measured in the same samples. Associations between u-mtDNA, UACR, and clinical disease parameters — including FEV1 % predicted, clinical measures of exercise tolerance, respiratory symptom burden, and chest CT measures of lung structure — were examined.RESULTS U-mtDNA and UACR levels were measured in never smokers (n = 64), smokers without airflow obstruction (n = 109), participants with mild/moderate COPD (n = 142), and participants with severe COPD (n = 168). U-mtDNA was associated with increased respiratory symptom burden, especially among smokers without COPD. Significant sex differences in u-mtDNA levels were observed, with females having higher u-mtDNA levels across all study subgroups. U-mtDNA associated with worse spirometry and CT emphysema in males only and with worse respiratory symptoms in females only. Similar associations were not found with UACR.CONCLUSION U-mtDNA levels may help to identify distinct clinical phenotypes and underlying pathobiological differences in males versus females with COPD.TRIAL REGISTRATION This study has been registered at ClinicalTrials.gov ( NCT01969344).FUNDING US NIH, National Heart, Lung and Blood Institute, supplemented by contributions made through the Foundation for the NIH and the COPD Foundation from AstraZeneca/MedImmune, Bayer, Bellerophon Therapeutics, Boehringer-Ingelheim Pharmaceuticals Inc., Chiesi Farmaceutici S.p.A., Forest Research Institute Inc., GlaxoSmithKline, Grifols Therapeutics Inc., Ikaria Inc., Novartis Pharmaceuticals Corporation, Nycomed GmbH, ProterixBio, Regeneron Pharmaceuticals Inc., Sanofi, Sunovion, Takeda Pharmaceutical Company, and Theravance Biopharma and Mylan.

Authors

William Z. Zhang, Michelle C. Rice, Katherine L. Hoffman, Clara Oromendia, Igor Z. Barjaktarevic, J. Michael Wells, Annette T. Hastie, Wassim W. Labaki, Christopher B. Cooper, Alejandro P. Comellas, Gerard J. Criner, Jerry A. Krishnan, Robert Paine III, Nadia N. Hansel, Russell P. Bowler, R. Graham Barr, Stephen P. Peters, Prescott G. Woodruff, Jeffrey L. Curtis, Meilan K. Han, Karla V. Ballman, Fernando J. Martinez, Augustine M.K. Choi, Kiichi Nakahira, Suzanne M. Cloonan, Mary E. Choi, the SPIROMICS Investigators

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Abstract

Interleukin-1β (IL-1β) is a key proinflammatory cytokine involved in the progression of many autoinflammatory and autoimmune diseases, including autoimmune inner ear disease (AIED). IL-1β inhibition has been shown to result in clinical hearing improvement in a small cohort of corticosteroid-resistant patients with AIED. Canonical processing of pro–IL-1β by caspase-1 generates an active 17-kDa fragment, capable of instigating a proinflammatory microenvironment. However, in response to LPS, PBMCs from patients with AIED uniquely express a 28-kDa IL-1β fragment, as compared with PBMCs from control subjects. We synthesized and compared the biologic activity of the 28-kDa fragment to the 17-kDa IL-1β product and the pro–IL-1 31-kDa protein. The 28-kDa IL-1β fragment induces IL-6, TNF-α, and CCL3 in PBMCs. Uniquely, only caspase-7 treatment showed a dose- and time-dependent increase in 28-kDa band generation. Mass spectrometry confirmed the putative caspase-7 cleavage site of pro–IL-1β, which was used to generate the 28-kDa fragment used for PBMC stimulation studies. Collectively, these results provide insight into the function of a poorly understood, processed 28-kDa form of IL-1β in patients with AIED that is uniquely generated by caspase-7 and is capable of activating further downstream proinflammatory cytokines. Further investigation may provide novel pharmacologic targets for the treatment of this rare disease.

Authors

Shresh Pathak, Andrea Vambutas

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Abstract

We previously established that DNA methyltransferase 3b (Dnmt3b) is the sole Dnmt responsive to fracture repair and that Dnmt3b expression is induced in progenitor cells during fracture repair. In the current study, we confirmed that Dnmt3b ablation in mesenchymal progenitor cells (MPCs) resulted in impaired endochondral ossification, delayed fracture repair, and reduced mechanical strength of the newly formed bone in Prx1-Cre;Dnmt3bf/f (Dnmt3bPrx1) mice. Mechanistically, deletion of Dnmt3b in MPCs led to reduced chondrogenic and osteogenic differentiation in vitro. We further identified Rbpjκ as a downstream target of Dnmt3b in MPCs. In fact, we located 2 Dnmt3b binding sites in the murine proximal Rbpjκ promoter and gene body and confirmed Dnmt3b interaction with the 2 binding sites by ChIP assays. Luciferase assays showed functional utilization of the Dnmt3b binding sites in murine C3H10T1/2 cells. Importantly, we showed that the MPC differentiation defect observed in Dnmt3b deficiency cells was due to the upregulation of Rbpjκ, evident by restored MPC differentiation upon Rbpjκ inhibition. Consistent with in vitro findings, Rbpjκ blockage via dual antiplatelet therapy reversed the differentiation defect and accelerated fracture repair in Dnmt3bPrx1 mice. Collectively, our data suggest that Dnmt3b suppresses Notch signaling during MPC differentiation and is necessary for normal fracture repair.

Authors

Jun Ying, Taotao Xu, Cuicui Wang, Hongting Jin, Peijian Tong, Jianjun Guan, Yousef Abu-Amer, Regis O’Keefe, Jie Shen

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Abstract

Vascular inflammation is present in many cardiovascular diseases, and exogenous glucocorticoids have traditionally been used as a therapy to suppress inflammation. However, recent data have shown that endogenous glucocorticoids, acting through the endothelial glucocorticoid receptor, act as negative regulators of inflammation. Here, we performed ChIP for the glucocorticoid receptor, followed by next-generation sequencing in mouse endothelial cells to investigate how the endothelial glucocorticoid receptor regulates vascular inflammation. We identified a role of the Wnt signaling pathway in this setting and show that loss of the endothelial glucocorticoid receptor results in upregulation of Wnt signaling both in vitro and in vivo using our validated mouse model. Furthermore, we demonstrate glucocorticoid receptor regulation of a key gene in the Wnt pathway, Frzb, via a glucocorticoid response element gleaned from our genomic data. These results suggest a role for endothelial Wnt signaling modulation in states of vascular inflammation.

Authors

Han Zhou, Sameet Mehta, Swayam Prakash Srivastava, Kariona Grabinska, Xinbo Zhang, Chris Wong, Ahmad Hedayat, Paola Perrotta, Carlos Fernández-Hernando, William C. Sessa, Julie E. Goodwin

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Abstract

Lung cancer (LC) is a leading cause of cancer-related deaths worldwide. Its rapid growth requires hyperactive catabolism of principal metabolic fuels. It is unclear whether fructose, an abundant sugar in current diets, is essential for LC. We demonstrated that, under the condition of coexistence of metabolic fuels in the body, fructose was readily used by LC cells in vivo as a glucose alternative via upregulating GLUT5, a major fructose transporter encoded by solute carrier family 2 member 5 (SLC2A5). Metabolomic profiling coupled with isotope tracing demonstrated that incorporated fructose was catabolized to fuel fatty acid synthesis and palmitoleic acid generation in particular to expedite LC growth in vivo. Both in vitro and in vivo supplement of palmitoleic acid could restore impaired LC propagation caused by SLC2A5 deletion. Furthermore, molecular mechanism investigation revealed that GLUT5-mediated fructose utilization was required to suppress AMPK and consequently activate mTORC1 activity to promote LC growth. As such, pharmacological blockade of in vivo fructose utilization using a GLUT5 inhibitor remarkably curtailed LC growth. Together, this study underscores the importance of in vivo fructose utilization mediated by GLUT5 in governing LC growth and highlights a promising strategy to treat LC by targeting GLUT5 to eliminate those fructose-addicted neoplastic cells.

Authors

Wen-Lian Chen, Xing Jin, Mingsong Wang, Dan Liu, Qin Luo, Hechuan Tian, Lili Cai, Lifei Meng, Rui Bi, Lei Wang, Xiao Xie, Guanzhen Yu, Lihui Li, Changsheng Dong, Qiliang Cai, Wei Jia, Wenyi Wei, Lijun Jia

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Abstract

The Notch signaling pathway mediates cell-cell communication regulating cell differentiation and proliferation and cell fate decisions in various tissues. In the urinary bladder, Notch acts as a tumor suppressor in mice, while mutations in Notch pathway components have been identified in human bladder cancer as well. Here we report that the genetic inactivation of Notch in mice leads to downregulation of cell-cell and cell-ECM interaction components, including proteins previously implicated in interstitial cystitis/bladder pain syndrome (IC/BPS), structural defects and mucosal sloughing, inflammation, and leaky urine-blood barrier. Molecular profiling of ailing mouse bladders showed similarities with IC/BPS patient tissue, which also presented low Notch pathway activity as indicated by reduced expression of canonical Notch targets. Urothelial integrity was reconstituted upon exogenous reactivation of the Notch pathway, implying a direct involvement of Notch. Despite damage and inflammation, urothelial cells failed to proliferate, uncovering a possible role for α4 integrin in urothelial homeostasis. Our data uncover a broad role for Notch in bladder homeostasis involving urothelial cell crosstalk with the microenvironment.

Authors

Varvara Paraskevopoulou, Vangelis Bonis, Vasilis S. Dionellis, Nikolaos Paschalidis, Pelagia Melissa, Evangelia Chavdoula, Eleni Vasilaki, Ioannis S. Pateras, Apostolos Klinakis

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Abstract

Chronic alcohol abuse has a detrimental effect on the brain and liver. There is no effective treatment for these patients, and the mechanism underlying alcohol addiction and consequent alcohol-induced damage of the liver/brain axis remains unresolved. We compared experimental models of alcoholic liver disease (ALD) and alcohol dependence in mice and demonstrated that genetic ablation of IL-17 receptor A (IL-17ra–/–) or pharmacological blockade of IL-17 signaling effectively suppressed the increased voluntary alcohol drinking in alcohol-dependent mice and blocked alcohol-induced hepatocellular and neurological damage. The level of circulating IL-17A positively correlated with the alcohol use in excessive drinkers and was further increased in patients with ALD as compared with healthy individuals. Our data suggest that IL-17A is a common mediator of excessive alcohol consumption and alcohol-induced liver/brain injury, and targeting IL-17A may provide a novel strategy for treatment of alcohol-induced pathology.

Authors

Jun Xu, Hsiao-Yen Ma, Xiao Liu, Sara Rosenthal, Jacopo Baglieri, Ryan McCubbin, Mengxi Sun, Yukinori Koyama, Cedric G. Geoffroy, Kaoru Saijo, Linshan Shang, Takahiro Nishio, Igor Maricic, Max Kreifeldt, Praveen Kusumanchi, Amanda Roberts, Binhai Zheng, Vipin Kumar, Karsten Zengler, Donald P. Pizzo, Mojgan Hosseini, Candice Contet, Christopher K. Glass, Suthat Liangpunsakul, Hidekazu Tsukamoto, Bin Gao, Michael Karin, David A. Brenner, George F. Koob, Tatiana Kisseleva

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Abstract

Few therapeutic methods exist for preventing preterm birth (PTB), or delivery before completing 37 weeks of gestation. In the US, progesterone (P4) supplementation is the only FDA-approved drug for use in preventing recurrent spontaneous PTB. However, P4 has limited effectiveness, working in only approximately one-third of cases. Computational drug repositioning leverages data on existing drugs to discover novel therapeutic uses. We used a rank-based pattern-matching strategy to compare the differential gene expression signature for PTB to differential gene expression drug profiles in the Connectivity Map database and assigned a reversal score to each PTB-drug pair. Eighty-three drugs, including P4, had significantly reversed differential gene expression compared with that found for PTB. Many of these compounds have been evaluated in the context of pregnancy, with 13 belonging to pregnancy category A or B — indicating no known risk in human pregnancy. We focused our validation efforts on lansoprazole, a proton-pump inhibitor, which has a strong reversal score and a good safety profile. We tested lansoprazole in an animal inflammation model using LPS, which showed a significant increase in fetal viability compared with LPS treatment alone. These promising results demonstrate the effectiveness of the computational drug repositioning pipeline to identify compounds that could be effective in preventing PTB.

Authors

Brian L. Le, Sota Iwatani, Ronald J. Wong, David K. Stevenson, Marina Sirota

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Abstract

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an autoimmune disease of the peripheral nerves that presents with either chronic progression or relapsing disease. Recent studies in samples from patients with CIDP and mouse models have delineated how defects in central (thymic) and peripheral (extrathymic) immune tolerance mechanisms can cause PNS autoimmunity. Notably, nerve parenchymal cells actively contribute to local autoimmunity and also control disease outcome. Here, we outline how emerging technologies increasingly enable an integrated view of how immune cells and PNS parenchymal cells communicate in CIDP. We also relate the known heterogeneity of clinical presentation with specific underlying mechanisms. For example, a severe subtype of CIDP with tremor is associated with pathogenic IgG4 autoantibodies against nodal and paranodal proteins. An improved understanding of pathogenic mechanisms in CIDP will form the basis for more effective mechanism-based therapies.

Authors

Jolien Wolbert, Mandy I. Cheng, Gerd Meyer zu Horste, Maureen A. Su

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Abstract

Plasma viral load (VL) and CD4+ T-cell count are widely used as biomarkers of HIV-1 replication, pathogenesis, and response to antiretroviral therapy (ART). However, the clinical potential of cell-associated (CA) HIV-1 molecular markers is much less understood. Here, we measured CA HIV-1 RNA and DNA in HIV-infected individuals treated with temporary ART initiated during primary HIV-1 infection. We demonstrate significant predictive value of CA RNA for: (a) the virological and immunological response to early ART, (b) the magnitude and time to viral rebound after discontinuation of early ART, and (c) the disease progression in the absence of treatment. Remarkably, when adjusted for CA RNA, plasma VL no longer appeared as an independent predictor of any clinical endpoint in this cohort. The potential of CA RNA as an HIV-1 clinical marker, in particular as a predictive biomarker of virological control after stopping ART, should be explored in the context of HIV-1 curative interventions.

Authors

Alexander O. Pasternak, Marlous L. Grijsen, Ferdinand W. Wit, Margreet Bakker, Suzanne Jurriaans, Jan M. Prins, Ben Berkhout

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Abstract

The specificity of antibodies (Abs) generated to influenza A virus (IAV) infection can significantly alter protection and viral clearance. At present, the impact of age upon this process is relatively unexplored. Here, we evaluated the Ab response in newborn and adult African green monkeys (AGM) following infection with IAV using a strain that enables us to determine the immunodominance (ID) hierarchy of the Ab response to hemagglutinin (HA), the principal target of protective Abs. This revealed altered ID patterns in the early IgM anti-HA response in newborns versus adults that converged over time. While the IgG ID profiles for HA in newborn and adult monkeys were similar, this was not the case for IgA. Importantly, HA stem-specific Abs were generated robustly and similarly in newborns and adults in terms of quality and quantity. Together these results demonstrate that newborns and adults can differ in the Ab ID pattern established following infection and that the ID pattern can vary across isotypes. In addition, newborns have the ability to generate potent HA stem-specific Ab responses. Our findings further the understanding of the newborn response to IAV antigens and inform the development of improved vaccines for this at-risk population.

Authors

Elene A. Clemens, Davide Angeletti, Beth C. Holbrook, Masaru Kanekiyo, Matthew J. Jorgensen, Barney S. Graham, Jonathan W. Yewdell, Martha A. Alexander-Miller

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Abstract

The blood hormone erythropoietin (EPO), upon binding to its receptor (EpoR), modulates high fat-diet (HFD)-induced obesity in mice, improves glucose tolerance, and prevents white adipose tissue inflammation. Transgenic mice with constitutive over-expression of human EPO solely in brain (Tg21) were used to assess the neuro-endocrine EPO effect without increasing the hematocrit. Male Tg21-mice resisted HFD-induced weight gain, showed lower serum ACTH, corticosterone and C-reactive protein levels, and prevented myeloid cell recruitment to hypothalamus compared with WT-males. HFD-induced hypothalamic inflammation (HI) and microglial activation were higher in male mice, and Tg21-males exhibited lower increase in HI than WT-males. Physiological EPO function in the brain also showed sexual dimorphism in regulating HFD response. Targeted deletion of EpoR gene expression in neuronal and glial cells worsened HFD-induced glucose intolerance in both male and female mice, but increased weight gain and HI in the hypothalamus in male mice only. Female estrogen production blocked reduced weight gain and HI. Both male and female Tg21-mice kept on normal-chow and HFD showed significantly improved glycemic control. Our data indicates that cerebral EPO regulates weight gain and HI in a sex-dependent response, distinct from EPO regulation of glycemic control, and independent of erythropoietic EPO response.

Authors

Soumyadeep Dey, Zhenzhong Cui, Oksana Gavrilova, XiaoJie Zhang, Max Gassmann, Constance T. Noguchi

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Abstract

Most prostate cancers depend on androgens for growth and therefore the mainstay treatment for advanced, recurrent or metastatic prostate cancer is androgen deprivation therapy (ADT). A prominent side effect in patients receiving ADT is an obese frailty syndrome that includes fat gain and sarcopenia, defined as the loss of muscle function accompanied by reduced muscle mass or quality. Mice bearing Pten deficient prostate cancers were examined to gain mechanistic insight into ADT-induced sarcopenic obesity. Castration induced fat gain as well as skeletal muscle mass and strength loss. Catabolic TGFß-family myokine protein levels were increased immediately prior to strength loss and pan-myokine blockade using a soluble receptor (ActRIIB-Fc) completely reversed the castration-induced sarcopenia. The onset of castration-induced strength and muscle mass loss, as well as the increase in catabolic TGFß-family myokine protein levels, were coordinately accelerated in tumor-bearing mice relative to tumor-free mice. Notably, GDF11 increased in muscle after castration only in tumor-bearing mice, but not in tumor free mice. An early surge of GDF11 in prostate tumor tissue and in the circulation suggests that endocrine GDF11 signaling from tumor to muscle is a major driver of the accelerated ADT-induced sarcopenic phenotype. In tumor-bearing mice, GDF11 blockade largely prevented castration-induced strength loss but did not preserve muscle mass, which confirms a primary role for GDF11 in muscle function and suggests an additional role for the other catabolic myokines.

Authors

Chunliu Pan, Neha Jaiswal Agrawal, Yanni Zulia, Shalini Singh, Kai Sha, James L. Mohler, Kevin H. Eng, Joe Chakkalakal, John J. Krolewski, Kent L. Nastiuk

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Abstract

We reported that transgenic mice expressing measles virus nucleocapsid protein (MVNP) in OCLs (MVNP mice) are a Paget’s disease (PD) model, and that osteoclasts (OCLs) from PD patients and MVNP mice express high levels of OCL-derived IGF1 (OCL-IGF1). To determine OCL-IGF1’s role in PD and normal bone remodeling, we generated WT and MVNP mice with targeted deletion of Igf1 in OCLs (Igf1-cKO) and MVNP/Igf1-cKO mice and assessed OCL-IGF1’s effects on bone mass, bone formation rate, ephrinB2/EphB4 expression on OCLs and osteoblasts (OBs) and pagetic bone lesions (PDLs). Forty percent of MVNP mice but no MVNP/Igf1-cKO mice had PDLs. BV/TV was decreased 60% in lumbar vertebrae and femurs of MVNP/Igf1-cKO vs. MVNP mice with PDLs and by 45% vs. all MVNP mice tested. Bone formation rates were decreased 50% in Igf1-cKO and MVNP/Igf1-cKO mice vs. WT and MVNP mice. MVNP mice had increased ephrinB2 and EphB4 levels in OCLs/OBs vs. WT and MVNP/Igf1-cKO, with none detectable in OCLs/OBs of Igf1-cKO mice. Mechanistically, IL-6 induced the increased OCL-IGF1 in MVNP mice. These results suggest that high OCL-IGF1 levels increase bone formation and PDLs in PD by enhancing ephrinB2/EphB4 expression in vivo, and that OCL-IGF1 may possibly contribute to normal bone remodeling.

Authors

Kazuaki Miyagawa, Yasuhisa Ohata, Jesus Delgado-Calle, Jumpei Teramachi, Hua Zhou, David W. Dempster, Mark A. Subler, Jolene J. Windle, John Chirgwin, G. David Roodman, Noriyoshi Kurihara

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