In-Press Preview
Abstract
Background: Epicardial adipose tissue (EAT) is the visceral fat depot of the heart. Inflammation of EAT is thought to contribute to coronary artery disease (CAD). Therefore, we hypothesized that the EAT of patients with CAD would have increased inflammatory gene expression compared to controls without CAD. Methods: 26 patients referred for cardiac surgery with (n=13) or without CAD (n=13) were consented. Samples of EAT and subcutaneous adipose tissue (SAT) were obtained at the time of surgery. Gene expression analysis was performed using Affymetrix Human Gene 1.0 ST arrays. Differential regulation was defined as a 1.5 fold change (ANOVA p<0.05). Results: When comparing SAT and EAT of controls, 693 genes were differentially expressed. 805 genes were differentially expressed between SAT and EAT in cases. Expression of 326 genes was different between EAT of cases and controls; expression of 14 genes was increased in cases, while 312 were increased in controls. qRT-PCR confirmed that there was no difference in expression of major inflammatory genes (CCL2, CCR2, TNFα, IL6, IL8, PAI1) between cases and controls. Immunohistochemistry demonstrated that there were more macrophages in EAT than SAT, but that there was no difference in the number or activation state between cases and controls. Conclusion: In contrast to prior studies, we did not find increased inflammatory gene expression in the EAT of patients with CAD in comparison to controls without CAD. We conclude that specific adipose tissue organ, rather than CAD status, is responsible for the majority of differential gene expression.
Authors
Timothy P. Fitzgibbons, Nancy Lee, Khanh-Van Tran, Sara Nicoloro, Mark Kelly, Stanley K.C. Tam, Michael P. Czech
Abstract
The cardiac hormone atrial natriuretic peptide (ANP) is a central regulator of blood volume and a therapeutic target in hypertension and heart failure. Enhanced ANP activity in such conditions through inhibition of the degradative enzyme neprilysin has shown clinical efficacy, but is complicated by consequences from simultaneous accumulation of a heterogeneous array of other hormones. Targets for specific ANP enhancement have not been available. Here, we describe a cis-acting antisense transcript (NPPA-AS1) which negatively regulates ANP expression in human cardiomyocytes. We show that NPPA-AS1 regulates ANP expression via facilitating interaction of the NPPA repressor REST (RE1-silencing transcription factor) binding to its promoter, rather than base-pairing with ANP mRNA. Expression of ANP mRNA and NPPA-AS1 was increased and correlated in isolated strained human cardiomyocytes and in hearts from patients with advanced heart failure. Further, inhibition of NPPA-AS1 in vitro and in vivo resulted in increased myocardial expression of ANP, increased circulating ANP, increased renal cGMP and lower blood pressure. The effects of NPPA-AS1 inhibition on NPPA expression in human cardiomyocytes were further marked under cell-strain conditions. Collectively, these results implicate the antisense transcript NPPA-AS1 as part of a physiologic self-regulatory ANP circuit and a viable target for specific ANP augmentation.
Authors
Selvi Celik, Mardjaneh Karbalaei Sadegh, Michael Morley, Carolina Roselli, Patrick T. Ellinor, Thomas Cappola, J. Gustav Smith, Olof Gidlof
Abstract
Atrial fibrillation (AF) is the most common heart rhythm disorder and a major cause of stroke. Unfortunately, current therapies for AF are suboptimal, largely because the molecular mechanisms underlying AF are poorly understood. Since the autonomic nervous system is thought to increase vulnerability to AF, we investigated in a rapid atrial pacing (RAP) canine model the anatomic and electrophysiological characteristics of autonomic remodeling in different regions of the left atrium. RAP led to marked hypertrophy of parent nerve bundles in the posterior left atrium (PLA), resulting in a global increase in parasympathetic and sympathetic innervation throughout the left atrium. Parasympathetic fibers were more heterogeneously distributed in the PLA when compared to other left atrial regions; this led to greater fractionation and disorganization of AF electrograms in the PLA. Computational modeling revealed that heterogeneously distributed parasympathetic activity exacerbates sympathetic substrate for wave break and reentry. We further discovered that levels of Nerve Growth Factor (NGF) were greatest in the left atrial appendage (LAA), where AF was most organized. Preferential NGF release by the LAA - likely a direct function of frequency and regularity of atrial stimulation - may have important implications for creation of a vulnerable AF substrate.
Authors
Georg Gussak, Anna Pfenniger, Lisa M. Wren, Mehul Gilani, Wenwei Zhang, Shin Yoo, David A. Johnson, Amy Burrell, Brandon Benefield, Gabriel M. Knight, Bradley P. Knight, Rod Passman, Jeffrey J. Goldberger, Gary Aistrup, J. Andrew Wasserstrom, Yohannes Shiferaw, Rishi Arora
Abstract
Clinical trials of high-dose androgen therapy for prostate cancer have shown promising efficacy but are limited by lack of criteria to identify likely responders. To elucidate factors that govern the growth-repressive effects of high-dose androgens we applied an unbiased integrative approach utilizing genetic screens and transcriptional profiling of prostate cancer cells with or without demonstrated phenotypic sensitivity to androgen-mediated growth repression. Through this comprehensive analysis, we identified genetic events and related signaling networks that determine the response to both high-dose androgen and androgen withdrawal. We applied these findings to develop a gene signature that may serve as an early indicator of treatment response and identify men with tumors amenable to high dose androgen therapy.
Authors
Michael D. Nyquist, Alexandra Corella, Osama Mohamad, Ilsa Coleman, Arja Kaipainen, Daniel A. Kuppers, Jared M. Lucas, Patrick J. Paddison, Stephen R. Plymate, Peter S. Nelson, Elahe A. Mostaghel
Abstract
Autoimmune diseases resulting from MHC class II-restricted autoantigen-specific T cell immunity include the systemic inflammatory autoimmune conditions, rheumatoid arthritis and vasculitis. While currently treated with broad-acting immunosuppressive drugs, a preferable strategy is to regulate antigen-specific effector T cells (Teff) to restore tolerance, by exploiting dendritic cell (DC) antigen presentation. We targeted draining lymph node (dLN) phagocytic DCs using liposomes encapsulating 1α,25-dihydroxyvitamin D3 (calcitriol) and antigenic peptide, to elucidate mechanisms of tolerance employed by DCs and responding T cells under resting and immunized conditions. PD-L1 expression was upregulated in dLN of immunized relative to naïve mice. Subcutaneous administration of liposomes encapsulating OVA323-339 and calcitriol targeted dLN PD-L1hi DCs of immunized mice and reduced their MHC class II expression. OVA323-339-calcitriol liposomes suppressed expansion, differentiation and function of Teff and induced Foxp3+ and IL-10+ peripheral (p)Treg in an antigen-specific manner, which was dependent on PD-L1. Peptide-calcitriol liposomes modulated CD40 expression by human DCs, and promoted Treg induction in vitro. Liposomes encapsulating calcitriol and disease-associated peptides suppressed the severity of rheumatoid arthritis and Goodpasture’s vasculitis models with suppression of antigen-specific memory T cell differentiation and function. Accordingly, peptide-calcitriol liposomes leverage DC PD-L1 for antigen-specific T cell regulation and induce antigen-specific tolerance in inflammatory autoimmune diseases.
Authors
Ryan Galea, Hendrik Nel, Meghna Talekar, Xiao Liu, Joshua D. Ooi, Megan Huynh, Sara Hadjigol, Kate J. Robson, Yi Tian Ting, Suzanne Cole, Karyn Cochlin, Shannon Hitchcock, Bijun Zeng, Suman Yekollu, Martine Boks, Natalie Goh, Helen Roberts, Jamie Rossjohn, Hugh H. Reid, Ben J. Boyd, Ravi Malaviya, David J. Shealy, Daniel G. Baker, Loui Madakamutil, A. Richard Kitching, Brendan J. O’Sullivan, Ranjeny Thomas
Abstract
Nitric oxide (NO) regulates blood pressure (BP) by binding the reduced heme iron (Fe2+) in soluble guanylyl cyclase (sGC) and relaxing vascular smooth muscle cells (SMC). We previously showed that sGC heme iron reduction (Fe3+ → Fe2+) is modulated by cytochrome b5 reductase 3 (CYB5R3). However, the in vivo role of SMC CYB5R3 in BP regulation remains elusive. Here, we generated conditional smooth muscle cell-specific Cyb5r3 knockout mice (SMC CYB5R3 KO) to test if SMC CYB5R3 loss impacts systemic BP in normotension and hypertension via regulation of sGC redox state. SMC CYB5R3 KO mice exhibited a 5.84 mmHg increase in BP and impaired acetylcholine-induced vasodilation in mesenteric arteries compared to controls. To drive sGC oxidation and elevate BP, we infused mice with angiotensin-II. We found SMC CYB5R3 KO mice exhibited a 14.75 mmHg BP increase and mesenteric arteries had diminished NO-dependent vasodilation, but increased responsiveness to sGC heme-independent activator BAY 58-2667 over controls. Furthermore, acute injection of BAY 58-2667 in angiotensin-II treated SMC CYB5R3 KO mice showed greater BP reduction compared to controls. Together, these data provide the first in vivo evidence that SMC CYB5R3 is a sGC heme reductase in resistance arteries and provides resilience against systemic hypertension development.
Authors
Brittany G. Durgin, Scott A. Hahn, Heidi M. Schmidt, Megan P. Miller, Neha Hafeez, Ilka Mathar, Daniel Freitag, Peter Sandner, Adam C. Straub
Abstract
We hypothesized that HIV-1 with dual-class but not single-class drug resistance mutations linked on the same viral genome, present in the virus population prior to initiation of antiretroviral therapy (ART), would be associated with failure of ART to suppress viremia. To test this hypothesis, we utilized an ultrasensitive single genome sequencing assay that detects rare HIV-1 variants with linked drug resistance mutations (DRMs). A case (ART failure) – control (non-failure) study was designed to assess whether linkage of DRMs in pre-ART plasma samples was associated with treatment outcome in the nevirapine /tenofovir/emtricitabine arm of the AIDS Clinical Trials Group A5208/OCTANE Trial 1 among women who had received prior single dose nevirapine. Ultrasensitive single genome sequencing revealed a significant association between pre-ART HIV variants with DRMs to 2 drug classes linked on the same genome (dual-class) and failure of three drug ART to suppress viremia. By contrast, linked, single-class DRMs were not associated with ART failure. We conclude that linked dual-class DRMs present before the initiation of ART are associated with ART failure, whereas linked single-class DRMs are not.
Authors
Valerie F. Boltz, Wei Shao, Michael J. Bale, Elias K. Halvas, Brian Luke, James A. McIntyre, Robert T. Schooley, Shahin Lockman, Judith S. Currier, Fred Sawe, Evelyn Hogg, Michael D. Hughes, Mary F. Kearney, John M. Coffin, John W. Mellors
Abstract
Previous studies have demonstrated the presence of microbial DNA in the fetal environment. However, it remains unclear whether this DNA represents viable bacteria and how it relates to the maternal microbiota across different body sites. We studied the microbiota of human and mouse dyads to understand these relationships, localize bacteria in the fetus, and demonstrate bacterial viability. In human preterm and full-term mother-infant dyads at the time of Cesarean delivery, the oral cavity and meconium of newborn infants born as early as 24 weeks of gestation contained a microbiota that was predicted to originate from in utero sources including the placenta. Using operative deliveries of pregnant mice under highly controlled, sterile conditions in the laboratory, composition, visualization, and viability of bacteria in the in utero compartment and fetal intestine were demonstrated by 16S rRNA gene sequencing, fluorescence in situ hybridization, and bacterial culture. The composition and predicted source of the fetal gut microbiota shifted between mid- and late gestation. Cultivatable bacteria in the fetal intestine were found during mid-gestation but not late gestation. Our results demonstrate a dynamic, viable mammalian fetal microbiota during in utero development.
Authors
Noelle Younge, Jessica R. McCann, Julie Ballard, Catherine Plunkett, Suhail Akhtar, Félix Araújo-Pérez, Amy Murtha, Debra Brandon, Patrick C. Seed
Abstract
Chagas disease is a life-long pathology resulting from Trypanosoma cruzi infection. It represents one of the most frequent causes of heart failure and sudden death in Latin America. Herein we provide evidence that aerobic glycolytic pathway activation in monocytes drives nitric oxide (NO) production, triggering tyrosine nitration (TN) on CD8 T cells and dysfunction in patients with chronic Chagas disease. Monocytes from patients exhibited higher frequency of hypoxia inducible factor (HIF)-1α and increased expression of its target genes/proteins. Non-classical monocytes are expanded in patients´ peripheral blood and represent an important source of NO. Monocytes entail CD8 T cell surface nitration since both the frequency of non-classical monocytes and that of NO-producing monocytes, positively correlated with the percentage of TN+ lymphocytes. Inhibition of glycolysis in (in vitro) infected peripheral blood mononuclear cells decreased the inflammatory properties of monocytes/macrophages diminishing the frequency of IL-1β- and NO-producing cells. In agreement, glycolysis inhibition reduced the percentage of TN+CD8 T cells improving their functionality. Altogether, these results clearly evidence that glycolysis governs oxidative stress on monocytes and modulates monocyte-T cell interplay in human chronic Chagas disease. Understanding the pathological immune mechanisms that sustains inflammatory environment in human pathology is key to design improved therapies.
Authors
Liliana María Sanmarco, Natalia Eberhardt, Gastón Bergero, Luz Piedad Quebrada Palacio, Pamela Martino Adami, Laura Marina Visconti, Ángel Ramón Minguez, Yolanda Hernández-Vasquez, Eugenio Antonio Carrera Silva, Laura Morelli, Miriam Postan, Maria Pilar Aoki
Abstract
Long-term survivors post hematopoietic stem cell transplantation are at high risk of infection which accounts for one-third of all deaths. Little is known about the cause of inferior host defense after immune cell reconstitution. Here, we exploited a murine syngeneic bone marrow transplantation (BMT) model of late infection with gammaherpesvirus 68 (MHV-68) to determine the role of conventional dendritic cell (cDC) trafficking in adaptive immunity in BMT mice. Post infection, the expression of chemokine Ccl21 in the lung is reduced and the migration of cDCs into lung draining lymph nodes (dLNs) is impaired in BMT mice, limiting the opportunity for cDCs to prime Th cells in the dLNs. While cDC subsets are redundant in priming Th1 cells, Notch2 functions in cDC2s are required for priming increased Th17 responses in BMT mice and cDC1s can lessen this activity. Importantly, Th17 cells can be primed both in the lungs and dLNs, allowing for increased Th17 responses without optimum cDC trafficking in BMT mice. Taken together, impaired cDC trafficking in BMT mice reduces protective Th1 responses and allows increased pathogenic Th17 responses. Thus, we have revealed a previously unknown mechanism for BMT procedures to cause long-term inferior immune responses to herpes viral infection.
Authors
Carol A. Wilke, Matthew M. Chadwick, Paul R. Chan, Bethany B. Moore, Xiaofeng Zhou
No posts were found with this tag.
