The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Peter Cserjesi - One of the best experts on this subject based on the ideXlab platform.
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expression level of HAND2 affects specification of enteric neurons and gastrointestinal function in mice
Gastroenterology, 2011Co-Authors: Fabien Dautreaux, Peter Cserjesi, Yuka Morikawa, Kara Gross Margolis, Jane A Roberts, Korey Stevanovic, Gary M Mawe, Nima Karamooz, Ankur Ahuja, Wanda SetlickAbstract:Background & Aims HAND2 is a basic helix-loop-helix transcription factor required for terminal differentiation of enteric neurons. We studied HAND2 haploinsufficient mice, to determine whether reduced expression of HAND2 allows sufficient enteric neurogenesis for survival, but not for development of a normal enteric nervous system (ENS). Methods Enteric transcripts that encode HAND2 and the neuron-specific embryonic lethal abnormal vision proteins HuB, HuC, and HuD were quantified. Immunocytochemistry was used to identify and quantify neurons. Apoptosis was analyzed with the terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling procedure. Intracellular microelectrodes were used to record inhibitory junction potentials. Gastrointestinal transit and colonic motility were measured in vivo. Results Levels of of enteric HAND2 transcripts were associated with genotypes of mice, in the following order: HAND2 +/+ > HAND2 LoxP/+ > HAND2 +/− > HAND2 LoxP/− . Parallel reductions were found in expression of HuD and in regional and phenotypic manners. Numbers of neurons, numbers of neuronal nitric oxide synthase + and calretinin + , but not substance P + or vasoactive intestinal peptide + neurons, decreased. No effects were observed in stomach or cecum. Apoptosis was not detected, consistent with the concept that HAND2 inhibits neuronal differentiation, rather than regulates survival. The amplitude of inhibitory junction potentials in colonic circular muscle was similar in HAND2 wild-type and haploinsufficient mice, although in haploinsufficient mice, the purinergic component was reduced and a nitrergic component appeared. The abnormal ENS of haploinsufficient mice slowed gastrointestinal motility but protected mice against colitis. Conclusions Reduced expression of factors required for development of the ENS can cause defects in the ENS that are subtle enough to escape detection yet cause significant abnormalities in bowel function.
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HAND2 Loss-of-Function in Hand1-Expressing Cells Reveals Distinct Roles in Epicardial and Coronary Vessel Development
Circulation Research, 2011Co-Authors: Ralston M. Barnes, Simon J. Conway, Peter Cserjesi, Yuka Morikawa, Nathan J Vandusen, Joshua W Vincentz, Beth A Firulli, Anthony B. FirulliAbstract:Rationale: The basic helix–loop–helix (bHLH) transcription factors Hand1 and HAND2 are essential for embryonic development. Given their requirement for cardiogenesis, it is imperative to determine their impact on cardiovascular function. Objective: To deduce the role of HAND2 within the epicardium. Method and Results: We engineered a Hand1 allele expressing Cre recombinase. Cardiac Hand1 expression is largely limited to cells of the primary heart field, overlapping little with HAND2 expression. Hand1 is expressed within the septum transversum, and the Hand1 lineage marks the proepicardial organ and epicardium. To examine Hand factor functional overlap, we conditionally deleted HAND2 from Hand1 -expressing cells. HAND2 mutants display defective epicardialization and fail to form coronary arteries, coincident with altered extracellular matrix deposition and Pdgfr expression. Conclusions: These data demonstrate a hierarchal relationship whereby transient Hand1 septum transversum expression defines epicardial precursors that are subsequently dependent on HAND2 function.
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HAND2 is required in the epithelium for palatogenesis in mice
Developmental Biology, 2009Co-Authors: Wei Xiong, Peter Cserjesi, Yuka Morikawa, Zunyi Zhang, Yu Lan, Rulang Jiang, Yiping ChenAbstract:The basic helix-loop-helix (bHLH) transcription factor HAND2 has been implicated in the development of multiple organs, including craniofacial organs. Mice carrying HAND2 hypomorphic alleles (HAND2LoxP/−) display a cleft palate phenotype. A specific deletion of the HAND2 branchial arch-specific enhancer also leads to a hypoplastic mandible and cleft palate formation in mice. However, the underlying mechanism of HAND2 regulation of palate development remains unknown. Here we show that HAND2 is expressed in both the epithelium and mesenchyme of the developing palate. While mesenchymal specific inactivation of HAND2 has no impact on palate development, epithelial specific deletion of HAND2 creates a cleft palate phenotype. HAND2 appears to exert distinct roles in the anterior and posterior palate. In the anterior palate of HAND2LoxP/− mice, premature death of periderm cells and a down-regulation of Shh are observed in the medial edge epithelium (MEE), accompanied by a decreased level of cell proliferation in the palatal mesenchyme. In the posterior palate, a lower dose of HAND2 causes aberrant periderm cell death on the surface of the epithelium, triggering abnormal fusion between the palatal shelf and mandible and preventing palatal shelf elevation. We further demonstrate that BMP activities are essential for the expression of HAND2 in the palate. We conclude that HAND2 is an intrinsic regulator in the epithelium and is required for palate development.
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cardiac neural crest expression of HAND2 regulates outflow and second heart field development
Circulation Research, 2008Co-Authors: Yuka Morikawa, Peter CserjesiAbstract:The cardiac neural crest (cNC) lineage plays key roles in heart development by directly contributing to heart structures and regulating development of other heart lineages. The basic helix–loop–helix factor HAND2 regulates development of cardiovascular structures and NC-derived tissues including those that contribute to face and peripheral nervous system. Although HAND2 is expressed in cNC, its role has not been examined because of an early embryonic lethality when HAND2 is deleted in the NC lineage. We find that the lethality is attributable to loss of norepinephrine synthesis that can be overcome by activating adrenergic receptors. In rescued embryos, loss of HAND2 in the NC lineage leads to the misalignment of the outflow tract and aortic arch arteries. Defects include pulmonary stenosis, interrupted aortic artery, retroesophageal right subclavian artery, and ventricular septum defect, which resemble congenital heart defects attributed to defects in the NC. HAND2 functions in part by regulating signaling from the cNC to other cardiac lineages but not by regulating migration or survival of the cNC. Loss of HAND2 in NC also uncovered a novel role for the cNC in regulating proliferation and differentiation of the second heart field–derived myocardium that persists late into development. These results show that the cNC functions as a major signaling center for heart development and HAND2 plays a pivotal role in regulating both cell-autonomous and -nonautonomous functions of the cNC.
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HAND2 determines the noradrenergic phenotype in the mouse sympathetic nervous system
Developmental Biology, 2007Co-Authors: Yuka Morikawa, Fabien Dautreaux, Michael D Gershon, Peter CserjesiAbstract:Abstract The basic helix–loop–helix (bHLH) transcription factor HAND2 has been shown to play a role in the development of the mammalian sympathetic nervous system (SNS); however, its precise role could not be uncovered because HAND2 is required for early embryonic survival. We therefore generated a conditional HAND2 knockout mouse line by excising HAND2 in Wnt1-Cre-expressing neural crest-derived cells. These mice die at 12.5 dpc with embryos showing severe cardiovascular and facial defects. Crest-derived cells, however, populate sites of SNS development and proliferate normally. Sympathetic precursors differentiate into neurons and express the pan-neuronal markers, β3-tubulin (Tuj1) and Hu showing that HAND2 is not essential for SNS neuronal differentiation. To determine whether HAND2 regulates noradrenergic differentiation, the levels of the norepinephrine biosynthetic enzymes, tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) was examined. Both enzymes were dramatically reduced in mutant embryos suggesting that the primary role of HAND2 in the SNS is determination of neuronal phenotype. Loss of HAND2 did not affect the expression of other members of the transcriptional circuit regulating SNS development, including Phox2a/b, Mash1 and Gata2/3; however, HAND2 was required for Hand1 expression. Our data suggest that the major role of HAND2 during SNS development is to permit sympathetic neurons to acquire a catecholaminergic phenotype.
Anthony B. Firulli - One of the best experts on this subject based on the ideXlab platform.
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Vincentz et al., 2016, PNAS.pdf
2019Co-Authors: Joshua W Vincentz, Jianwen Que, Anthony B. FirulliAbstract:Cranial neural crest cells (crNCCs) migrate from the neural tube to the pharyngeal arches (PAs) of the developing embryo and, sub- sequently, differentiate into bone and connective tissue to form the mandible. Within the PAs, crNCCs respond to local signaling cues to partition into the proximo-distally oriented subdomains that convey positional information to these developing tissues. Here, we show that the distal-most of these subdomains, the distal cap, is marked by expression of the transcription factor Hand1 (H1) and gives rise to the ectomesenchymal derivatives of the lower incisors. We uncover a H1 enhancer sufficient to drive reporter gene expression within the crNCCs of the distal cap. We show that bone morphogenic pro- tein (BMP) signaling and the transcription factor HAND2 (H2) syner- gistically regulate H1 distal cap expression. Furthermore, the homeodomain proteins distal-less homeobox 5 (DLX5) and DLX6 reciprocally inhibit BMP/H2-mediated H1 enhancer regulation. These findings provide insights into how multiple signaling pathways di- rect transcriptional outcomes that pattern the developing jaw.
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Vincentz et al., 2017, PLoS Genetics.pdf
2019Co-Authors: Joshua W Vincentz, Anthony B. Firulli, Wenjun ZhangAbstract:The left ventricle of the heart drives blood flow throughout the body. Impaired left ventricle function, associated either with heart failure or with certain, severe cardiac birth defects, constitutes a significant cause of mortality. Understanding how heart muscle grows is vital to developing improved treatments for these diseases. Unfortunately, genetic tools necessary to study the left ventricle have been lacking. Here we engineer the first mouse line to enable specific genetic study of the left ventricle. We show that, unlike in the adult heart, the embryonic left ventricle is remarkably tolerant of cell death, as remaining cells have the capacity to proliferate and to restore heart function. Conversely, disruption of two related genes, Hand1 and HAND2, within the left ventricle causes cells to assume the wrong identity, and to consequently overgrow and impair cardiac function. Ablation of these mutant cells rescues heart function. We conclude that selective removal of defective heart muscle and replacement with healthy cells may provide an effective therapy to treat heart failure.
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Hand factor ablation causes defective left ventricular chamber development and compromised adult cardiac function
2017Co-Authors: Joshua W Vincentz, Kevin P. Toolan, Wenjun Zhang, Anthony B. FirulliAbstract:Coordinated cardiomyocyte growth, differentiation, and morphogenesis are essential for heart formation. We demonstrate that the bHLH transcription factors Hand1 and HAND2 play critical regulatory roles for left ventricle (LV) cardiomyocyte proliferation and morphogenesis. Using an LV-specific Cre allele (Hand1LV-Cre), we ablate Hand1-lineage cardiomyocytes, revealing that DTA-mediated cardiomyocyte death results in a hypoplastic LV by E10.5. Once Hand1-linage cells are removed from the LV, and Hand1 expression is switched off, embryonic hearts recover by E16.5. In contrast, conditional LV loss-of-function of both Hand1 and HAND2 results in aberrant trabeculation and thickened compact zone myocardium resulting from enhanced proliferation and a breakdown of compact zone/trabecular/ventricular septal identity. Surviving Hand1;HAND2 mutants display diminished cardiac function that is rescued by concurrent ablation of Hand-null cardiomyocytes. Collectively, we conclude that, within a mixed cardiomyocyte population, removal of defective myocardium and replacement with healthy endogenous cardiomyocytes may provide an effective strategy for cardiac repair.
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HAND2 elevates cardiomyocyte production during zebrafish heart development and regeneration
PMC, 2014Co-Authors: Yocheved L Schindler, Anthony B. Firulli, Beth A Firulli, Kristina M Garske, Jinhu Wang, Kenneth D Poss, Deborah YelonAbstract:Embryonic heart formation requires the production of an appropriate number of cardiomyocytes; likewise, cardiac regeneration following injury relies upon the recovery of lost cardiomyocytes. The basic helix-loop-helix (bHLH) transcription factor HAND2 has been implicated in promoting cardiomyocyte formation. It is unclear, however, whether HAND2 plays an instructive or permissive role during this process. Here, we find that overexpression of HAND2 in the early zebrafish embryo is able to enhance cardiomyocyte production, resulting in an enlarged heart with a striking increase in the size of the outflow tract. Our evidence indicates that these increases are dependent on the interactions of HAND2 in multimeric complexes and are independent of direct DNA binding by HAND2. Proliferation assays reveal that HAND2 can impact cardiomyocyte production by promoting division of late-differentiating cardiac progenitors within the second heart field. Additionally, our data suggest that HAND2 can influence cardiomyocyte production by altering the patterning of the anterior lateral plate mesoderm, potentially favoring formation of the first heart field at the expense of hematopoietic and vascular lineages. The potency of HAND2 during embryonic cardiogenesis suggested that HAND2 could also impact cardiac regeneration in adult zebrafish; indeed, we find that overexpression of HAND2 can augment the regenerative proliferation of cardiomyocytes in response to injury. Together, our studies demonstrate that HAND2 can drive cardiomyocyte production in multiple contexts and through multiple mechanisms. These results contribute to our understanding of the potential origins of congenital heart disease and inform future strategies in regenerative medicine.
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A Phox2- and HAND2-dependent Hand1 cis-regulatory element reveals a unique gene dosage requirement for HAND2 during sympathetic neurogenesis.
The Journal of Neuroscience, 2012Co-Authors: Joshua W Vincentz, Andrew B. Fleming, Marthe J. Howard, Nathan J Vandusen, Beth A Firulli, Michael Rubart, Anthony B. FirulliAbstract:Neural crest cell specification and differentiation to a sympathetic neuronal fate serves as an important model for neurogenesis and depends upon the function of both bHLH transcription factors, notably HAND2, and homeodomain transcription factors, including Phox2b. Here, we define a 1007 bp cis -regulatory element 5′ of the Hand1 gene sufficient to drive reporter expression within the sympathetic chain of transgenic mice. Comparative genomic analyses uncovered evolutionarily conserved consensus-binding sites within this element, which chromatin immunoprecipitation and electrophoretic mobility shift assays confirm are bound by HAND2 and Phox2b. Mutational analyses revealed that the conserved Phox2 and E-box binding sites are necessary for proper cis -regulatory element activity, and expression analyses on both HAND2 conditionally null and hypomorphic backgrounds demonstrate that HAND2 is required for reporter activation in a gene dosage-dependent manner. We demonstrate that HAND2 and Hand1 differentially bind the E-boxes in this cis -regulatory element, establishing molecular differences between these two factors. Finally, we demonstrate that Hand1 is dispensable for normal tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) expression in sympathetic neurons, even when HAND2 gene dosage is concurrently reduced by half. Together, these data define a tissue-specific Hand1 cis -regulatory element controlled by two factors essential for the development of the sympathetic nervous system and provide in vivo regulatory evidence to support previous findings that HAND2, rather than Hand1, is predominantly responsible for regulating TH, DBH, and Hand1 expression in developing sympathetic neurons.
Eric N. Olson - One of the best experts on this subject based on the ideXlab platform.
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transcription of the non coding rna upperhand controls HAND2 expression and heart development
Nature, 2016Co-Authors: Kelly M Anderson, John M Shelton, Douglas M Anderson, John R Mcanally, Rhonda Basselduby, Eric N. OlsonAbstract:Transcription of a long non-coding RNA, known as upperhand (Uph) located upstream of the HAND2 transcription factor is required to maintain transcription of the HAND2 gene by RNA polymerase, and blockade of Uph expression leads to heart defects and embryonic lethality in mice. The expression of the transcription factor HAND2 is controlled by several upstream enhancer elements, confined in a region delimited by the presence of the chromatin mark H3K27Ac. Eric Olson and colleagues have found that the transcription of long non-coding RNA located upstream of HAND2 is required to maintained these chromatin marks and let the RNA polymerase transcribe the HAND2 gene. Preventing the expression of this long non-coding RNA with a termination cassette leads to defects in heart development in mice. HAND2 is an ancestral regulator of heart development and one of four transcription factors that control the reprogramming of fibroblasts into cardiomyocytes1,2,3,4. Deletion of HAND2 in mice results in right ventricle hypoplasia and embryonic lethality1,5. HAND2 expression is tightly regulated by upstream enhancers6,7 that reside within a super-enhancer delineated by histone H3 acetyl Lys27 (H3K27ac) modifications8. Here we show that transcription of a HAND2-associated long non-coding RNA, which we named upperhand (Uph), is required to maintain the super-enhancer signature and elongation of RNA polymerase II through the HAND2 enhancer locus. Blockade of Uph transcription, but not knockdown of the mature transcript, abolished HAND2 expression, causing right ventricular hypoplasia and embryonic lethality in mice. Given the substantial number of uncharacterized promoter-associated long non-coding RNAs encoded by the mammalian genome9, the Uph–HAND2 regulatory partnership offers a mechanism by which divergent non-coding transcription can establish a permissive chromatin environment.
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HAND2 function in second heart field progenitors is essential for cardiogenesis
Developmental Biology, 2011Co-Authors: Takatoshi Tsuchihashi, Eric N. Olson, Jun Maeda, Chong Hyun Shin, Kathryn N Ivey, Brian L Black, Hiroyuki Yamagishi, Deepak SrivastavaAbstract:Cardiogenesis involves the contributions of multiple progenitor pools, including mesoderm-derived cardiac progenitors known as the first and second heart fields. Disruption of genetic pathways regulating individual subsets of cardiac progenitors likely underlies many forms of human cardiac malformations. HAND2 is a member of the basic helix loop helix (bHLH) family of transcription factors and is expressed in numerous cell lineages that contribute to the developing heart. However, the early embryonic lethality of HAND2-null mice has precluded lineage-specific study of its function in myocardial progenitors. Here, we generated and used a floxed allele of HAND2 to ablate its expression in specific cardiac cell populations at defined developmental points. We found that HAND2 expression within the mesoderm-derived second heart field progenitors was required for their survival and deletion in this domain recapitulated the complete HAND2-null phenotype. Loss of HAND2 at later stages of development and in restricted domains of the second heart field revealed a spectrum of cardiac anomalies resembling forms of human congenital heart disease. Molecular analyses of HAND2 mutant cells revealed several genes by which HAND2 may influence expansion of the cardiac progenitors. These findings demonstrate that HAND2 is essential for survival of second heart field progenitors and that the graded loss of HAND2 function in this cardiac progenitor pool can cause a spectrum of congenital heart malformation.
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affinity purification of microrna 133a with the cardiac transcription factor HAND2
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Ryan P Dalton, Eric N. Olson, Ning Liu, Richard H GoodmanAbstract:Predictions of microRNA-mRNA interactions typically rely on bioinformatic algorithms, but these algorithms only suggest the possibility of microRNA binding and may miss important interactions as well as falsely predict others. We developed an affinity purification approach to empirically identify microRNAs associated with the 3′UTR of the mRNA encoding HAND2, a transcription factor essential for cardiac development. In addition to miR-1, a known regulator of HAND2 expression, we determined that the HAND2 3′UTR also associated with miR-133a, a microRNA cotranscribed with miR-1 in cardiac and muscle cells. Using a sequential binding assay, we showed that miR-1 and miR-133a could occupy the HAND2 3′UTR concurrently. miR-133a inhibited HAND2 expression in tissue culture models, and miR-133a double knockout mice had elevated levels of HAND2 mRNA and protein. We conclude that HAND2 is regulated by miR-133a in addition to miR-1. The affinity purification assay should be generally applicable for identifying other microRNA-mRNA interactions.
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dna binding dependent and independent functions of the HAND2 transcription factor during mouse embryogenesis
Development, 2009Co-Authors: Ning Liu, Ana C. Barbosa, James A. Richardson, Shelby L Chapman, Hiromi Yanagisawa, Svetlana Bezprozvannaya, Eric N. OlsonAbstract:The basic helix-loop-helix (bHLH) transcription factor HAND2 is required for growth and development of the heart, branchial arches and limb buds. To determine whether DNA binding is required for HAND2 to regulate the growth and development of these different embryonic tissues, we generated mutant mice in which the HAND2 locus was modified by a mutation (referred to as HAND2(EDE)) that abolished the DNA-binding activity of HAND2, leaving the remainder of the protein intact. In contrast to HAND2 null embryos, which display right ventricular hypoplasia and vascular abnormalities, causing severe growth retardation by E9.5 and death by E10.5, early development of the heart appeared remarkably normal in homozygous HAND2(EDE) mutant embryos. These mutant embryos also lacked the early defects in growth of the branchial arches seen in HAND2 null embryos and survived up to 2 to 3 days longer than did HAND2 null embryos. However, HAND2(EDE) mutant embryos exhibited growth defects in the limb buds similar to those of HAND2 null embryos. These findings suggest that HAND2 regulates tissue growth and development in vivo through DNA binding-dependent and -independent mechanisms.
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The Hand1 and HAND2 transcription factors regulate expansion of the embryonic cardiac ventricles in a gene dosage-dependent manner
Development (Cambridge England), 2004Co-Authors: David G. Mcfadden, Deepak Srivastava, Ana C. Barbosa, James A. Richardson, Michael D. Schneider, Eric N. OlsonAbstract:The basic helix-loop-helix transcription factors Hand1 and HAND2 display dynamic and spatially restricted expression patterns in the developing heart. Mice that lack HAND2 die at embryonic day 10.5 from right ventricular hypoplasia and vascular defects, whereas mice that lack Hand1 die at embryonic day 8.5 from placental and extra-embryonic abnormalities that preclude analysis of its potential role in later stages of heart development. To determine the cardiac functions of Hand1, we generated mice harboring a conditional Hand1-null allele and excised the gene by cardiac-specific expression of Cre recombinase. Embryos homozygous for the cardiac Hand1 gene deletion displayed defects in the left ventricle and endocardial cushions, and exhibited dysregulated ventricular gene expression. However, these embryos survived until the perinatal period when they died from a spectrum of cardiac abnormalities. Creation of Hand1/2 double mutant mice revealed gene dose-sensitive functions of Hand transcription factors in the control of cardiac morphogenesis and ventricular gene expression. These findings demonstrate that Hand factors play pivotal and partially redundant roles in cardiac morphogenesis, cardiomyocyte differentiation and cardiac-specific transcription.
Marthe J. Howard - One of the best experts on this subject based on the ideXlab platform.
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distinct roles of HAND2 in developing and adult autonomic neurons
Developmental Neurobiology, 2016Co-Authors: Sabine Stanzel, Marthe J. Howard, Hermann Rohrer, Jutta Stubbusch, Abhijeet Pataskar, Thomas Deller, Uwe Ernsberger, Vijay K Tiwari, Konstantina TsarovinaAbstract:The bHLH transcription factor HAND2 is essential for the acquisition and maintenance of noradrenergic properties of embryonic sympathetic neurons and controls neuroblast proliferation. HAND2 is also expressed in embryonic and postnatal parasympathetic ganglia and remains expressed in sympathetic neurons up to the adult stage. Here, we address its function in developing parasympathetic and adult sympathetic neurons. We conditionally deleted HAND2 in the parasympathetic sphenopalatine ganglion by crossing a line of floxed HAND2 mice with DbhiCre transgenic mice, taking advantage of the transient Dbh expression in parasympathetic ganglia. HAND2 elimination does not affect Dbh expression and sphenopalatine ganglion size at E12.5 and E16.5, in contrast to sympathetic ganglia. These findings demonstrate different functions for HAND2 in the parasympathetic and sympathetic lineage. Our previous HAND2 knockdown in postmitotic, differentiated chick sympathetic neurons resulted in decreased expression of noradrenergic marker genes but it was unclear whether HAND2 is required for maintaining noradrenergic neuron identity in adult animals. We now show that HAND2 elimination in adult Dbh-expressing sympathetic neurons does not decrease the expression of Th and Dbh, in contrast to the situation during development. However, gene expression profiling of adult sympathetic neurons identified 75 HAND2-dependent target genes. Interestingly, a notable proportion of down-regulated genes (15%) encode for proteins with synaptic and neurotransmission functions. These results demonstrate a change in HAND2 target genes during maturation of sympathetic neurons. Whereas HAND2 controls genes regulating noradrenergic differentiation during development, HAND2 seems to be involved in the regulation of genes controlling neurotransmission in adult sympathetic neurons. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1111-1124, 2016.
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A Phox2- and HAND2-dependent Hand1 cis-regulatory element reveals a unique gene dosage requirement for HAND2 during sympathetic neurogenesis.
The Journal of Neuroscience, 2012Co-Authors: Joshua W Vincentz, Andrew B. Fleming, Marthe J. Howard, Nathan J Vandusen, Beth A Firulli, Michael Rubart, Anthony B. FirulliAbstract:Neural crest cell specification and differentiation to a sympathetic neuronal fate serves as an important model for neurogenesis and depends upon the function of both bHLH transcription factors, notably HAND2, and homeodomain transcription factors, including Phox2b. Here, we define a 1007 bp cis -regulatory element 5′ of the Hand1 gene sufficient to drive reporter expression within the sympathetic chain of transgenic mice. Comparative genomic analyses uncovered evolutionarily conserved consensus-binding sites within this element, which chromatin immunoprecipitation and electrophoretic mobility shift assays confirm are bound by HAND2 and Phox2b. Mutational analyses revealed that the conserved Phox2 and E-box binding sites are necessary for proper cis -regulatory element activity, and expression analyses on both HAND2 conditionally null and hypomorphic backgrounds demonstrate that HAND2 is required for reporter activation in a gene dosage-dependent manner. We demonstrate that HAND2 and Hand1 differentially bind the E-boxes in this cis -regulatory element, establishing molecular differences between these two factors. Finally, we demonstrate that Hand1 is dispensable for normal tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) expression in sympathetic neurons, even when HAND2 gene dosage is concurrently reduced by half. Together, these data define a tissue-specific Hand1 cis -regulatory element controlled by two factors essential for the development of the sympathetic nervous system and provide in vivo regulatory evidence to support previous findings that HAND2, rather than Hand1, is predominantly responsible for regulating TH, DBH, and Hand1 expression in developing sympathetic neurons.
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targeted deletion of HAND2 in enteric neural precursor cells affects its functions in neurogenesis neurotransmitter specification and gangliogenesis causing functional aganglionosis
Development, 2011Co-Authors: Jun Lei, Marthe J. HowardAbstract:Targeted deletion of the bHLH DNA-binding protein HAND2 in the neural crest, impacts development of the enteric nervous system (ENS), possibly by regulating the transition from neural precursor cell to neuron. We tested this hypothesis by targeting HAND2 deletion in nestin-expressing neural precursor (NEP) cells. The mutant mice showed abnormal ENS development, resulting in lethal neurogenic pseudo-obstruction. Neurogenesis of neurons derived from NEP cells identified a second nestin non-expressing neural precursor (NNEP) cell in the ENS. There was substantial compensation for the loss of neurons derived from the NEP pool by the NNEP pool but this was insufficient to abrogate the negative impact of HAND2 deletion. HAND2-mediated regulation of proliferation affected both neural precursor and neuron numbers. Differentiation of glial cells derived from the NEP cells was significantly decreased with no compensation from the NNEP pool of cells. Our data indicate differential developmental potential of NEPs and NNEPs; NNEPs preferentially differentiate as neurons, whereas NEPs give rise to both neurons and glial cells. Deletion of HAND2 also resulted in complete loss of NOS and VIP and a significant decrease in expression of choline acetyltransferase and calretinin, demonstrating a role for HAND2 in neurotransmitter specification and/or expression. Loss of HAND2 resulted in a marked disruption of the developing neural network, exemplified by lack of a myenteric plexus and extensive overgrowth of fibers. Thus, HAND2 is essential for neurogenesis, neurotransmitter specification and neural network patterning in the developing ENS.
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targeted deletion of HAND2 in cardiac neural crest derived cells influences cardiac gene expression and outflow tract development
Developmental Biology, 2010Co-Authors: Kristen L Holler, Anthony B. Firulli, Joshua W Vincentz, Tyler J Hendershot, Sophia E Troy, Marthe J. HowardAbstract:The basic helix-loop-helix DNA binding protein HAND2 has critical functions in cardiac development both in neural crest-derived and mesoderm-derived structures. Targeted deletion of HAND2 in the neural crest has allowed us to genetically dissect HAND2-dependent defects specifically in outflow tract and cardiac cushion independent of HAND2 functions in mesoderm-derived structures. Targeted deletion of HAND2 in the neural crest results in misalignment of the aortic arch arteries and outflow tract, contributing to development of double outlet right ventricle (DORV) and ventricular septal defects (VSD). These neural crest-derived developmental anomalies are associated with altered expression of HAND2-target genes we have identified by gene profiling. A number of HAND2 direct target genes have been identified using ChIP and ChIP-on-chip analyses. We have identified and validated a number of genes related to cell migration, proliferation/cell cycle and intracellular signaling whose expression is affected by HAND2 deletion in the neural crest and which are associated with development of VSD and DORV. Our data suggest that HAND2 is a multifunctional DNA binding protein affecting expression of target genes associated with a number of functional interactions in neural crest-derived cells required for proper patterning of the outflow tract, generation of the appropriate number of neural crest-derived cells for elongation of the conotruncus and cardiac cushion organization. Our genetic model has made it possible to investigate the molecular genetics of neural crest contributions to outflow tract morphogenesis and cell differentiation.
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the bhlh transcription factor HAND2 is essential for the maintenance of noradrenergic properties in differentiated sympathetic neurons
Developmental Biology, 2009Co-Authors: Mirko Schmidt, Marthe J. Howard, Uwe Ernsberger, Shengyin Lin, Manuela Pape, Matthias Stanke, Kazuto Kobayashi, Hermann RohrerAbstract:The basic helix-loop-helix transcription factor HAND2 is essential for the proliferation and noradrenergic differentiation of sympathetic neuron precursors during development. Here we address the function of HAND2 in postmitotic, differentiated sympathetic neurons. Knockdown of endogenous HAND2 in cultured E12 chick sympathetic neurons by siRNA results in a significant (about 60%) decrease in the expression of the noradrenergic marker genes dopamine-β-hydroxylase (DBH) and tyrosine hydroxylase (TH). In contrast, expression of the pan-neuronal genes TuJ1, HuC and SCG10 was not affected. To analyze the in vivo role of HAND2 in differentiated sympathetic neurons we used mice harboring a conditional HAND2-null allele and excised the gene by expression of Cre recombinase under control of the DBH promotor. Mouse embryos homozygous for HAND2 gene deletion showed decreased sympathetic neuron number and TH expression was strongly reduced in the residual neuron population. The in vitro HAND2 knockdown also enhances the CNTF-induced expression of the cholinergic marker genes vesicular acetylcholine transporter (VAChT) and choline acetyltransferase (ChAT). Taken together, these findings demonstrate that the HAND2 transcription factor plays a key role in maintaining noradrenergic properties in differentiated neurons.
Joseph Kwong - One of the best experts on this subject based on the ideXlab platform.
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long non coding rna HAND2 as1 inhibits invasion and metastasis in endometrioid endometrial carcinoma through inactivating neuromedin u
Cancer Letters, 2018Co-Authors: Xueying Yang, Chi Chiu Wang, Jone Trovik, Tony K H Chung, Joseph KwongAbstract:Abstract Endometrioid endometrial carcinoma (EEC) is one of the common causes of cancer-related mortality in women. Mounting evidences suggest that long noncoding RNAs (lncRNAs) function in multiple cancers. In this study, we discovered that HAND2-AS1, a lncRNA transcribed antisense adjacent to Heart and Neural Crest Derivatives Expressed 2 (HAND2) in chromosome 4q33-34, is significantly down-regulated in EEC. HAND2-AS1 and HAND2 were frequently down-regulated in EEC tissues, especially in poor differentiated tumor tissues. Down-regulation of HAND2-AS1 and HAND2 was correlated with tumor grade, lymph node metastasis and recurrence of EEC patients. HAND2-AS1 and HAND2 were co-downregulated by promoter DNA hypermethylation in EEC. Overexpression of HAND2-AS1 in EEC cells demonstrated that HAND2-AS1 suppressed migration and invasion of EEC cells. Similarly, overexpression of HAND2 also inhibited migration and invasion EEC cells indicating that HAND2-AS1 and HAND2 had a concordant role in the progression of EEC. However, HAND2 was not regulated by HAND2-AS1 in EEC. Furthermore, the anti-tumorigenic effect of HAND2-AS1 was mediated by down-regulating NMU, which has an oncogenic role in EEC. Our findings therefore provide the first evidence that HAND2-AS1 is a critical tumor suppressor in EEC.
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abstract 3448 lncrna HAND2 as1 inactivates neuromedin u nmu and inhibits tumor invasion and metastasis in endometrioid endometrial carcinoma
Cancer Research, 2017Co-Authors: Xueying Yang, Chi Chiu Wang, Joseph Kwong, Yu Zhao, Yuying Li, Jiajian Zhou, Jianzhang Wang, Huating Wang, Tony K H ChungAbstract:Background Endometrioid endometrial carcinoma (EEC) is one of the common cause of cancer-related mortality in women. Despite progress in diagnostics and treatment of EEC, its prognosis remains poor. Mounting evidence suggest that long noncoding RNAs (lncRNAs) function in mutiple human cancers. Aberrant lncRNA expression may predict tumor outcome of patients and have served as diagnostic or prognostic markers. In this study, we investigated the expression levels and functions of lncRNAs in EEC. Methods Differentially expressed lncRNAs involved in EEC were identified by using publically available RNA-Seq data. The expression of 18 dysregulated lncRNA candidates was verified in 5 NE tissues, 5 EEC tissues and 5 EEC cell lines (HEC1-A, HEC1-B, AN3CA, KLE and RL95-2) by real-time polymerase chain reaction (PCR). Further, we selected the most misexpressed lncRNA and confirmed the expression level of the lncRNA in 59 EEC tissues and 24 NE tissues by real-time PCR and correlated the lncRNA expression levels with the clinical pathological characteristics. The promoter methylation assay was used to analyze the methylation level of the lncRNA in EEC. The lncRNA methylation status was confirmed by bisulfite genomic sequencing. Cell proliferation assays, wound healing assays, and invasion and migration assays were performed to determine the biological functions of the lncRNA in EEC cells. To discover the direct targets of the lncRNA in EEC, we performed RNA-sequence analysis in EEC cells overexpressed with the lncRNA and target genes were further studied by functional studies in vitro (knockdown assay and overexpression rescue assay). Results We discovered that HAND2-AS1, a lncRNA transcribed antisense adjacent to Heart and Neural Crest Derivatives Expressed 2 (HAND2), was significantly downregulated lncRNA in EEC. HAND2-AS1 and HAND2 was frequently downregulated in EEC tissues, especially in poor differentiated tumor tissues. Downregulation of HAND2-AS1 and HAND2 was correlated with tumor grade, lymph node metastasis and recurrence of EEC patients. HAND2-AS1 and HAND2 was co-downregulated by promoter hypermethylation in EEC. HAND2-AS1 suppressed EEC cell migration and invasion but not cell growth. Similarly, HAND2 also inhibited EEC cell migration and invasion indicating that HAND2-AS1 and HAND2 have a concordant role in the progression of EEC. Moreover, the anti-tumorigenic effect of HAND2-AS1 was mediated by downregulating NMU, which had an oncogenic role in EEC. Conclusions Our findings provide the first evidence that HAND2-AS1 is a critical tumor suppressor in EEC and may constitute a prognostic biomarker in EEC. Note: This abstract was not presented at the meeting. Citation Format: Xueying Yang, Yu Zhao, Kun Sun, Yuying Li, Jiajian Zhou, Jianzhang Wang, Hao Sun, Chi Chiu Wang, Joseph Kwong, Huating Wang, Tony Kwok Hung Chung. LncRNA HAND2-AS1 inactivates neuromedin U (NMU) and inhibits tumor invasion and metastasis in endometrioid endometrial carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3448. doi:10.1158/1538-7445.AM2017-3448
