Hand2 Expression Research Articles

Long-term, induced expression of Hand2 in peripheral sympathetic neurons ameliorates sarcopenia in geriatric mice.

BackgroundThe discovery of adrenoceptors, which mediate the effects of the sympathetic nervous system neurotransmitter norepinephrine on specific tissues, sparked the development of sympathomimetics that have profound influence on skeletal muscle mass. However, chronic administration has serious side effects that preclude their use for muscle‐wasting conditions such as sarcopenia, the age‐dependent decline in muscle mass, force, and power. Devising interventions that can adjust neurotransmitter release to changing physiological demands will require understanding how the sympathetic nervous system affects muscle motor innervation and muscle mass, which will prevent sarcopenia‐associated impaired mobility, falls, institutionalization, co‐morbidity, and premature death. Here, we tested the hypothesis that prolonged heart and neural crest derivative 2 (Hand2) expression in peripheral sympathetic neurons (SNs) ameliorates sympathetic muscle denervation, motor denervation, and sarcopenia in geriatric mice.MethodsWe delivered either a viral vector encoding the transcription factor Hand2 or an empty vector (EV) driven to SNs by the PRSx8 promoter by injecting the saphenous vein in 16‐month‐old C57BL/6 mice that were sacrificed 10–11 months later. Studies relied on sympathetic and muscle immunohistochemistry analysed by confocal microscopy, nerve and muscle protein expression assessed by immunoblots, nerve‐evoked and muscle‐evoked maximal muscle contraction force, extensor digitorum longus (EDL) muscle RNA sequencing, SN real‐time PCR, and tests of physical performance using an inverted‐cling grip test and in an open‐arena setting.ResultsExamining the mice 10–11 months later, we found that inducing Hand2 expression in peripheral SNs preserved (i) the number of neurons (EV: 0.32 ± 0.03/μm2, n = 6; Hand2: 0.92 ± 0.08/μm2, n = 7; P < 0.0001) and size (EV: 279 ± 18 μm2, n = 6; Hand2: 396 ± 18 μm2, n = 7; P < 0.0001); (ii) lumbricalis muscle sympathetic innervation (EV: 1.4 ± 1.5 μm/μm2, n = 5; Hand2: 12 ± 1.8 μm/μm2, n = 5; P < 0.001); (iii) tibialis anterior, gastrocnemius, EDL, and soleus muscles weight and whole‐body strength (EV: 48 ± 6.4 s, n = 6; Hand2: 102 ± 6.8 s, n = 6; P < 0.001); (iv) EDL type IIb, IIx, and II/IIx and soleus type I, IIa, IIx, IIa/IIx, and IIb/IIx myofibre cross‐sectional area; (v) nerve‐evoked (EV: 16 ± 2.7 mN; Hand2: 30 ± 4.4 mN; P < 0.001) and muscle‐evoked (EV: 24 ± 3.8 mN, n = 5; Hand2: 38 ± 3.0 mN, n = 8; P < 0.001) muscle force by 150 Hz–3 s pulses; and (vi) motor innervation assessed by measuring presynaptic/postsynaptic neuromuscular junction area overlay.ConclusionsPreserving Hand2 expression in SNs from middle‐aged to very old mice attenuates decreases in muscle mass and force by (i) maintaining skeletal muscle sympathetic and motor innervation, (ii) improving membrane and total acetylcholine receptor stability and nerve‐evoked and muscle‐evoked muscle contraction, (iii) preventing the elevation of inflammation and myofibrillar protein degradation markers, and (iv) increasing muscle autophagy.

Bmp Signaling Regulates Hand1 in a Dose-Dependent Manner during Heart Development.

The bone morphogenetic protein (Bmp) signaling pathway and the basic helix–loop–helix (bHLH) transcription factor Hand1 are known key regulators of cardiac development. In this study, we investigated the Bmp signaling regulation of Hand1 during cardiac outflow tract (OFT) development. In Bmp2 and Bmp4loss-of-function embryos with varying levels of Bmp in the heart, Hand1 is sensitively decreased in response to the dose of Bmp expression. In contrast, Hand1 in the heart is dramatically increased in Bmp4 gain-of-function embryos. We further identified and characterized the Bmp/Smad regulatory elements in Hand1. Combined transfection assays and chromatin immunoprecipitation (ChIP) experiments indicated that Hand1 is directly activated and bound by Smads. In addition, we found that upon the treatment of Bmp2 and Bmp4, P19 cells induced Hand1 expression and favored cardiac differentiation. Together, our data indicated that the Bmp signaling pathway directly regulates Hand1 expression in a dose-dependent manner during heart development.

Osr1 couples intermediate mesoderm cell fate with temporal dynamics of vessel progenitor cell differentiation.

Transcriptional regulatory networks refine gene expression boundaries to define the dimensions of organ progenitor territories. Kidney progenitors originate within the intermediate mesoderm (IM), but the pathways that establish the boundary between the IM and neighboring vessel progenitors are poorly understood. Here, we delineate roles for the zinc-finger transcription factor Osr1 in kidney and vessel progenitor development. Zebrafish osr1 mutants display decreased IM formation and premature emergence of lateral vessel progenitors (LVPs). These phenotypes contrast with the increased IM and absent LVPs observed with loss of the bHLH transcription factor Hand2, and loss of hand2 partially suppresses osr1 mutant phenotypes. hand2 and osr1 are expressed together in the posterior mesoderm, but osr1 expression decreases dramatically prior to LVP emergence. Overexpressing osr1 during this timeframe inhibits LVP development while enhancing IM formation, and can rescue the osr1 mutant phenotype. Together, our data demonstrate that osr1 modulates the extent of IM formation and the temporal dynamics of LVP development, suggesting that a balance between levels of osr1 and hand2 expression is essential to demarcate the kidney and vessel progenitor territories.

Expression dynamics of HAND1/2 in invitro human cardiomyocyte differentiation.

SummaryHand1 and Hand2 are transcriptional factors, and knockout mice of these genes show left and right ventricular hypoplasia, respectively. However, their function and expression in human cardiogenesis are not well studied. To delineate their expressions and assess their functions in human cardiomyocytes (CMs) in vitro, we established two triple-reporter human induced pluripotent stem cell lines that express HAND1mCherry, HAND2EGFP and either MYH6-driven iRFP670 or tagBFP constitutively and investigated their expression dynamics during cardiac differentiation. On day 5 of the differentiation, HAND1 expression marked cardiac progenitor cells. We profiled the CM subpopulations on day 20 with RNA sequencing and found that mCherry+ CMs showed higher proliferative ability than mCherry− CMs and identified a gene network of LEF1, HAND1, and HAND2 to regulate proliferation in CMs. Finally, we identified CD105 as a surface marker of highly proliferative CMs.

A show of Hands: Novel and conserved expression patterns of teleost hand paralogs during craniofacial, heart, fin, peripheral nervous system and gut development.

Hand genes are required for the development of the vertebrate jaw, heart, peripheral nervous system, limb, gut, placenta, and decidua. Two Hand paralogues, Hand1 and Hand2, are present in most vertebrates, where they mediate different functions yet overlap in expression. In ray-finned fishes, Hand gene expression and function is only known for the zebrafish, which represents the rare condition of having a single Hand gene, hand2. Here we describe the developmental expression of hand1 and hand2 in the cichlid Copadichromis azureus. hand1 and hand2 are expressed in the cichlid heart, paired fins, pharyngeal arches, peripheral nervous system, gut, and lateral plate mesoderm with different degrees of overlap. Hand gene expression in the gut, peripheral nervous system, and pharyngeal arches may have already been fixed in the lobe- and ray-finned fish common ancestor. In other embryonic regions, such as paired appendages, hand2 expression was fixed, while hand1 expression diverged in lobe- and ray-finned fish lineages. In the lateral plate mesoderm and arch associated catecholaminergic cells, hand1 and hand2 swapped expression between divergent lineages. Distinct expression of cichlid hand1 and hand2 in the epicardium and myocardium of the developing heart may represent the ancestral pattern for bony fishes.

Deletion of a Hand1 lncRNA-Containing Septum Transversum Enhancer Alters lncRNA Expression but Is Not Required for Hand1 Expression.

We have previously identified a Hand1 transcriptional enhancer that drives expression within the septum transversum, the origin of the cells that contribute to the epicardium. This enhancer directly overlaps a common exon of a predicted family of long non-coding RNAs (lncRNA) that are specific to mice. To interrogate the necessity of this Hand1 enhancer, as well as the importance of these novel lncRNAs, we deleted the enhancer sequences, including the common exon shared by these lncRNAs, using genome editing. Resultant homozygous Hand1 enhancer mutants (Hand1ΔST/ΔST) present with no observable phenotype. Assessment of lncRNA expression reveals that Hand1ΔST/ΔST mutants effectively eliminate detectable lncRNA expression. Expression analysis within Hand1ΔST/ΔST mutant hearts indicates higher levels of Hand1 than in controls. The generation of Hand1 compound heterozygous mutants with the Hand1LacZ null allele (Hand1ΔST/LacZ) also did not reveal any observable phenotypes. Together these data indicate that deletion of this Hand1 enhancer and by consequence a family of murine-specific lncRNAs does not impact embryonic development in observable ways.

Evolutionary transcriptomics implicates HAND2 in the origins of implantation and regulation of gestation length

The developmental origins and evolutionary histories of cell types, tissues, and organs contribute to the ways in which their dysfunction produces disease. In mammals, the nature, development and evolution of maternal-fetal interactions likely influence diseases of pregnancy. Here we show genes that evolved expression at the maternal-fetal interface in Eutherian mammals play essential roles in the evolution of pregnancy and are associated with immunological disorders and preterm birth. Among these genes is HAND2, a transcription factor that suppresses estrogen signaling, a Eutherian innovation allowing blastocyst implantation. We found dynamic HAND2 expression in the decidua throughout the menstrual cycle and pregnancy, gradually decreasing to a low at term. HAND2 regulates a distinct set of genes in endometrial stromal fibroblasts including IL15, a cytokine also exhibiting dynamic expression throughout the menstrual cycle and gestation, promoting migration of natural killer cells and extravillous cytotrophoblasts. We demonstrate that HAND2 promoter loops to an enhancer containing SNPs implicated in birth weight and gestation length regulation. Collectively, these data connect HAND2 expression at the maternal-fetal interface with evolution of implantation and gestational regulation, and preterm birth.

1112HAND1 knockdown disrupts trophoblast but not placental endothelial global gene expression

We previously reported disrupted placental structure, and vascular changes in placentas from fetuses with Congenital Heart Defects. Signaling between trophoblast and villous endothelium is proposed for proper placental development and function. We hypothesize that disruption of genes associated with CHD within the trophoblast impacts fetal endothelium and results in dysregulated placental vasculature in CHD fetuses. A model of human cytotrophoblast, BeWo choriocarcinoma cells and isolated human placental microvascular endothelial cells (HPMVEC) were treated for 48 hrs with HAND1 siRNA/lipofectamine. Additionally, control HPMVECs were exposed to conditioned BeWo media (+/- HAND1) for 48 hrs. Cells were harvested and total RNA isolated. RNA was sequenced on an Illumina NextSeq 550 platform (single end reads 85bp, read depth 25M). The Galaxy Bioinformatic Platform was used for quality control, alignment (Bowtie2) and generation of read counts (Feature Counts). Normalization and differential gene expression analyses were conducted using general linear modeling in edgeR package from Bioconductor. Significance was determined using a fold change cut off of >1.5 and raw p<0.05. Overrepresentation analysis was performed using Panther DB for Reactome pathways and GO terms Direct HAND1 knockdown in the BeWo choriocarcinoma cell line caused downregulation of 632 genes, and upregulation of 102 genes. Overrepresentation analysis identified disruption to pathways including cell differentiation, neurogenesis, localization, and cell projection organization. In contrast, direct HAND1 knockdown in HPMVECs resulted in minimal disruption to global gene expression with differential expression in just 18 genes. Indirect HAND1 disruption did not alter HPMVEC gene expression. Disruption to HAND1 expression significantly alters gene expression profile in trophoblast but not HPMVEC, either directly or indirectly. Disruption to the structure and vasculature of the placenta in cases of CHD is likely primarily due to abnormal trophoblast development.

HAND1 and BARX1 Act as Transcriptional and Anatomic Determinants of Malignancy in Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumor (GIST) arises from interstitial cells of Cajal (ICC) or their precursors, which are present throughout the gastrointestinal tract. Although gastric GIST is commonly indolent and small intestine GIST more aggressive, a molecular understanding of disease behavior would inform therapy decisions in GIST. Although a core transcription factor (TF) network is conserved across GIST, accessory TFs HAND1 and BARX1 are expressed in a disease state-specific pattern. Here, we characterize two divergent transcriptional programs maintained by HAND1 and BARX1, and evaluate their association with clinical outcomes. We evaluated RNA sequencing and TF chromatin immunoprecipitation with sequencing in GIST samples and cultured cells for transcriptional programs associated with HAND1 and BARX1. Multiplexed tissue-based cyclic immunofluorescence and IHC evaluated tissue- and cell-level expression of TFs and their association with clinical factors. We show that HAND1 is expressed in aggressive GIST, modulating KIT and core TF expression and supporting proliferative cellular programs. In contrast, BARX1 is expressed in indolent and micro-GISTs. HAND1 and BARX1 expression were superior predictors of relapse-free survival, as compared with standard risk stratification, and they predict progression-free survival on imatinib. Reflecting the developmental origins of accessory TF programs, HAND1 was expressed solely in small intestine ICCs, whereas BARX1 expression was restricted to gastric ICCs. Our results define anatomic and transcriptional determinants of GIST and molecular origins of clinical phenotypes. Assessment of HAND1 and BARX1 expression in GIST may provide prognostic information and improve clinical decisions on the administration of adjuvant therapy.

Heart and neural crest derivative 2-induced preservation of sympathetic neurons attenuates sarcopenia with aging.

BackgroundSarcopenia, or age‐dependent decline in muscle force and power, impairs mobility, increasing the risk of falls, institutionalization, co‐morbidity, and premature death. The discovery of adrenoceptors, which mediate the effects of the sympathetic nervous system (SNS) neurotransmitter norepinephrine on specific tissues, sparked the development of sympathomimetics that have profound influence on skeletal muscle mass. However, chronic administration has serious side effects that preclude their use for muscle‐wasting conditions. Interventions that can adjust neurotransmitter release to changing physiological demands depend on understanding how the SNS affects neuromuscular transmission, muscle motor innervation, and muscle mass.MethodsWe examined age‐dependent expression of the heart and neural crest derivative 2 (Hand2), a critical transcription factor for SN maintenance, and we tested the possibility that inducing its expression exclusively in sympathetic neurons (SN) will prevent (i) motor denervation, (ii) impaired neuromuscular junction (NMJ) transmission, and (iii) loss of muscle mass and function in old mice. To test this hypothesis, we delivered a viral vector carrying Hand2 expression or an empty vector exclusively in SNs by vein injection in 16‐month‐old C57BL/6 mice that were sacrificed 6 months later. Techniques include RNA‐sequencing, real‐time PCR, genomic DNA methylation, viral vector construct, tissue immunohistochemistry, immunoblot, confocal microscopy, electrophysiology, and in vivo mouse physical performance.ResultsHand2 expression declines throughout life, but inducing its expression increased (i) the number and size of SNs, (ii) muscle sympathetic innervation, (iii) muscle weight and force and whole‐body strength, (iv) myofiber size but not muscle fibre‐type composition, (v) NMJ transmission and nerve‐evoked muscle force, and (vi) motor innervation in old mice. Additionally, the SN controls a set of genes to reduce inflammation and to promote transcription factor activity, cell signalling, and synapse in the skeletal muscle. Hand2 DNA methylation may contribute, at least partially, to gene silencing.ConclusionsSelective expression of Hand2 in the mouse SNs from middle age through old age increases muscle mass and force by (i) regulating skeletal muscle sympathetic and motor innervation; (ii) improving acetylcholine receptor stability and NMJ transmission; (iii) preventing inflammation and myofibrillar protein degradation; (iv) increasing autophagy; and (v) probably enhancing protein synthesis.

The Transcription Factor HAND1 Is Involved in Cortical Bone Mass through the Regulation of Collagen Expression.

Temporal and/or spatial alteration of collagen family gene expression results in bone defects. However, how collagen expression controls bone size remains largely unknown. The basic helix-loop-helix transcription factor HAND1 is expressed in developing long bones and is involved in their morphogenesis. To understand the functional role of HAND1 and collagen in the postnatal development of long bones, we overexpressed Hand1 in the osteochondroprogenitors of model mice and found that the bone volumes of cortical bones decreased in Hand1Tg/+;Twist2-Cre mice. Continuous Hand1 expression downregulated the gene expression of type I, V, and XI collagen in the diaphyses of long bones and was associated with decreased expression of Runx2 and Sp7/Osterix, encoding transcription factors involved in the transactivation of fibril-forming collagen genes. Members of the microRNA-196 family, which target the 3′ untranslated regions of COL1A1 and COL1A2, were significantly upregulated in Hand1Tg/+;Twist2-Cre mice. Mass spectrometry revealed that the expression ratios of alpha 1(XI), alpha 2(XI), and alpha 2(V) in the diaphysis increased during postnatal development in wild-type mice, which was delayed in Hand1Tg/+;Twist2-Cre mice. Our results demonstrate that HAND1 regulates bone size and morphology through osteochondroprogenitors, at least partially by suppressing postnatal expression of collagen fibrils in the cortical bones.

Developmental toxicity of Clerodendrum cyrtophyllum turcz ethanol extract in zebrafish embryo

Ethnopharmacological relevanceClerodendrum cyrtophyllum Turcz has been used in traditional medicine for the treatment of various diseases. In spite of its therapeutic applications, research on its toxicity and teratogenicity is still limited. Aim of the studyThe study aimed to investigate the developmental toxicity of the ethanol extract of C. cyrtophyllum (EE) in zebrafish embryo model. Material and methodsMajor compounds from crude ethanol extract of Clerodendron cyrtophyllum Turcz leaves were determined using HPLC-DAD-Orbitrap-MS analysis. The developmental toxicity of EE were investigated using zebrafish embryo model. Zebrafish embryos at 6 h post-fertilization (hpf) were treated with EE at different concentrations. Egg coagulation, mortality, hatching, yolk sac edema, pericardial edema and teratogenicity were recorded each day for during a 5-day exposure. At time point 120 hpf, body length, pericardial area, heartbeat and yolk sac area were assessed. In order to elucidate molecular mechanisms for the developmental toxicity of EE, we further evaluated the effects of the EE on the expression of genes involved on signaling pathways affecting fish embryo’s development such as heart development (gata5, myl7, myh6, has2, hand2, nkx 2.5), oxidative stress (cat, sod1, gpx4, gstp2), wnt pathway (β-catenin, wnt3a, wnt5, wnt8a, wnt11), or cell apoptosis (p53, bax, bcl2, casp3, casp8, casp9, apaf-1, gadd45bb) using qRT-PCR analysis. ResultsOur results demonstrated that three major components including acteoside, cirsilineol and cirsilineol-4'-O-β-D-glucopyranoside were identified from EE. EE exposure during 6–96 h post-fertilization (hpf) at doses ranging from 80 to 200 μg/mL increased embryo mortality and reduced hatching rate. EE exposure at 20 and 40 μg/mL until 72–120 hpf induced a series of malformations, including yolk sac edema, pericardial edema, spine deformation, shorter body length. Based on two prediction models using a teratogenic index (TI), a 25% lethality concentration (LD25) and the no observed-adverse-effect level (NOAEL), EE is considered as teratogenic for zebrafish embryos with TI (LC50/EC50) and LD25/NOAEC values at 96 hpf reaching 3.87 and 15.73 respectively. The mRNA expression levels of p53, casp8, bax/bcl2, gstp2, nkx2.5, wnt3a, wnt11, gadd45bb and gata5 were significantly upregulated by EE exposure at 20 and 40 μg/mL while the expression of wnt5, hand2 and bcl2 were downregulated. ConclusionsThese results provide evidence for toxicity effects of EE to embryo stages and provide an insight into the potential toxicity mechanisms on embryonic development.

Abstract B22: Cell state and lineage specification are controlled by epigenetic landscapes regulating the core transcriptional regulatory circuitry in pediatric neuroblastoma

Abstract Metazoan cell identity and lineage specification are regulated by a small group of super-enhancer-driven transcription factors unique to each cell type, referred to as the core regulatory circuit (CRC). In pediatric neuroblastoma, the survival of transformed neuroblasts is dependent on the activity of an autoregulatory CRC loop that includes HAND2, ISL1, PHOX2B, GATA3, and TBX2. Treatment of adrenergic neuroblastoma cells with all-trans retinoic (ATRA) induced strong morphologic changes and cell cycle arrest concomitant with differentiation and senescence. Tumor-bearing MYCN-transgenic zebrafish treated with retinoic acid exhibited a 70% reduction in tumor size in vivo. During reprogramming of cellular identity with ATRA, neuroblastoma cells exhibited altered expression of most adrenergic CRC transcription factors. The gene expression and protein levels of MYCN, ISL1, PHOX2B, GATA3, and ASCL1 were substantially reduced in ATRA-treated relative to control cells, while the expression of HAND2 was only modestly suppressed. Conversely, the expression levels of TBX2 and TBX3 were increased by more than 2-fold following ATRA treatment. Altered gene expression was frequently associated with loss or enrichment of H3K27ac-modified chromatin within the topologically associating domains regulating these genes. De novo super-enhancers were created over a subset of elevated transcription factors, indicating the emergence of a novel CRC framework that regulates the identity of differentiated neural crest-derived cells. We evaluated several genes, including RARA, MEIS1, and SOX4, by high-throughput ChIP-seq followed by whole-genome alignment and found that a novel autoregulatory loop of ATRA-regulated transcription factors co-opts the MYCN-driven gene expression program leading to both global transcriptional suppression and upregulation of genes and pathways associated with neuronal differentiation. Activation of MYC or MYCN by enhancer hijacking via translocations involving the HAND2 gene locus, which is not repressed by retinoic acid signaling, circumvents ATRA-induced the loss of MYCN expression and stabilizes the oncogenic transcriptome. These results shed light on the essential role of CRC transcription factors in regulating neuroblastoma cell survival and could guide the development of future transcriptionally directed therapeutics. Citation Format: Mark W. Zimmerman, Adam D. Durbin, Brian J. Abraham, Alla Berezovskaya, Shuning He, Felix Oppel, Richard A. Young, A. Thomas Look. Cell state and lineage specification are controlled by epigenetic landscapes regulating the core transcriptional regulatory circuitry in pediatric neuroblastoma [abstract]. In: Proceedings of the AACR Special Conference on the Advances in Pediatric Cancer Research; 2019 Sep 17-20; Montreal, QC, Canada. Philadelphia (PA): AACR; Cancer Res 2020;80(14 Suppl):Abstract nr B22.

The transcription factor HAND2 up-regulates transcription of the IL15 gene in human endometrial stromal cells

Cyclic changes of the human endometrium, such as proliferation, secretion, and decidualization, occur during regular menstrual cycles. Heart- and neural crest derivatives-expressed transcript 2 (HAND2) is a key transcription factor in progestin-induced decidualization of human endometrial stromal cells (ESCs). It has been suggested that HAND2 regulates interleukin 15 (IL15), a key immune factor required for the activation and survival of uterine natural killer (uNK) cells. Activated uNK cells can promote spiral artery remodeling and secrete cytokines to induce immunotolerance. To date, no studies have evaluated the transcription factors that regulate IL15 expression in human ESCs. In the present study, we examined whether HAND2 controls IL15 transcriptional regulation in human ESCs. Quantitative RT-PCR and histological analyses revealed that HAND2 and IL15 levels increase considerably in the secretory phase of human endometrium tissues. Results from ChIP-quantitative PCR suggested that HAND2 binds to a putative HAND2 motif, which we identified in the upstream region of the human IL15 gene through in silico analysis. Using a luciferase reporter assay, we found that the upstream region of the human IL15 gene up-regulates reporter gene activities in response to estradiol and a progestin representative (medroxyprogesterone) in ESCs. The upstream region of the human IL15 gene also exhibited increasing responsiveness to transfection with a HAND2 expression vector. Of note, deletion and substitution variants of the putative HAND2 motif in the upstream region of IL15 did not respond to HAND2 transfection. These findings confirm that HAND2 directly up-regulates human IL15 transcription in ESCs.

Integrated bioinformatics identifies the dysregulation induced by aberrant gene methylation in colorectal carcinoma

Colorectal carcinoma (CRC) is one of the most common cancers, and is associated with a poor clinical outcome. The key genes and potential prognostic markers in colorectal carcinoma remain to be identified and explored for clinical application. DNA expression/methylation profiles were downloaded from the Gene Expression Omnibus (GEO) database to identify differentially expressed/methylated genes (DEGs and DEMs). A total of 255 genes and 372 genes were identified as being up-regulated and down-regulated, respectively, in GSE113513, GSE81558, and GSE89076. There were a total of 3350 hypermethylated genes and 443 hypomethylated genes identified in GSE48684. Twenty genes were found to be hypermethylated as well as down-regulated, and a functional enrichment analysis revealed that these genes were mainly involved in cancer-related pathways. Among these 20 genes, GPM6A, HAND2 and C2orf40 were related to poor outcomes in cancer patients based on a survival analysis. Concurrent decreases of GPM6A, HAND2 and C2orf40 protein expression were observed in highly-differentiated colorectal carcinoma tissues, and higher expression levels were found in undifferentiated or minimally-differentiated colorectal carcinoma tissues. In conclusion, 20 genes were found to be downregulated and hypermethylated in CRC, among which GPM6A, HAND2 and C2orf40 were explored for their potential prognostic value.

Alternative splicing of jnk1a in zebrafish determines first heart field ventricular cardiomyocyte numbers through modulation of hand2 expression.

The planar cell polarity pathway is required for heart development and whilst the functions of most pathway members are known, the roles of the jnk genes in cardiac morphogenesis remain unknown as mouse mutants exhibit functional redundancy, with early embryonic lethality of compound mutants. In this study zebrafish were used to overcome early embryonic lethality in mouse models and establish the requirement for Jnk in heart development. Whole mount in-situ hybridisation and RT-PCR demonstrated that evolutionarily conserved alternative spliced jnk1a and jnk1b transcripts were expressed in the early developing heart. Maternal zygotic null mutant zebrafish lines for jnk1a and jnk1b, generated using CRISPR-Cas9, revealed a requirement for jnk1a in formation of the proximal, first heart field (FHF)-derived portion of the cardiac ventricular chamber. Rescue of the jnk1a mutant cardiac phenotype was only possible by injection of the jnk1a EX7 Lg alternatively spliced transcript. Analysis of mutants indicated that there was a reduction in the size of the hand2 expression field in jnk1a mutants which led to a specific reduction in FHF ventricular cardiomyocytes within the anterior lateral plate mesoderm. Moreover, the jnk1a mutant ventricular defect could be rescued by injection of hand2 mRNA. This study reveals a novel and critical requirement for Jnk1 in heart development and highlights the importance of alternative splicing in vertebrate cardiac morphogenesis. Genetic pathways functioning through jnk1 may be important in human heart malformations with left ventricular hypoplasia.

Prenatal exposure to a phthalate mixture leads to multigenerational and transgenerational effects on uterine morphology and function in mice

Phthalates are commonly used plasticizers and additives that are found in plastic containers, children’s toys and medical equipment. Phthalates are classified as endocrine-disrupting chemicals and exposure to phthalates has been associated with several human health risks including reproductive defects. Most studies focus on a single phthalate; however, humans are exposed to a mixture of phthalates daily. We hypothesized that prenatal exposure to an environmentally relevant phthalate mixture would lead to changes in uterine morphology and function in mice in a multi-generational manner. To test this hypothesis, pregnant CD-1 dams were orally dosed with vehicle or a phthalate mixture (20 μg/kg/day, 200 μg/kg/day, 200 mg/kg/day, and 500 mg/kg/day) from gestational day 10.5 to parturition. The mixture contained 35 % diethyl phthalate, 21 % di-(2-ethylhexyl) phthalate, 15 % dibutyl phthalate, 15 % diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. The F1 pups were maintained and mated to produce two more generations (F2 and F3). At the age of 13 months, all females were euthanized and tissue samples were collected in diestrus. Our results showed that exposure to a phthalate mixture caused a decrease in progesterone levels in the treated groups in the F2 generation. The 200 mg/kg/day treatment group showed a decreased and increased luminal epithelial cell proliferation in the F1 and F2 generations respectively. In addition, these mice in the F2 generation had reduced Hand2 expression in the sub-epithelial stroma compared to the controls. A higher incidence of multilayered luminal epithelium and large dilated endometrial glands were observed in the phthalate mixture exposed groups in all generations. The mixture also caused a higher incidence of smooth muscle actin expression and collagen deposition in the endometrium compared to controls. Collectively, our results demonstrate that prenatal exposure to an environmentally relevant phthalate mixture can have adverse effects on female reproductive functions.

Zebrafish Pax1a and Pax1b are required for pharyngeal pouch morphogenesis and ceratobranchial cartilage development

Pharyngeal arches are derived from all three germ layers and molecular interactions among the tissue types are required for proper development of subsequent pharyngeal cartilages; however, the mechanisms underlying this process are not fully described. Here we report that in zebrafish, Pax1a and Pax1b have overlapping and essential functions in pharyngeal pouch morphogenesis and subsequent ceratobranchial cartilage development. Both pax1a and pax1b are co-expressed in pharyngeal pouches, and time-lapse imaging of a novel Tg(pax1b:eGFP) enhancer trap line further revealed the sequential segmental development of pharyngeal pouches. Zebrafish pax1a−/−; pax1b−/− double mutant embryos generated by CRISPR-Cas9 mutagenesis exhibit unsegmented pharyngeal pouches 2–5 with small outpocketings. Endodermal expression of fgf3, tbx1 and edn1 is also absent in pharyngeal pouches 2–5 at 36 h post fertilization (hpf). Loss of ceratobranchial cartilage 1–4 and reduced or absent expression of dlx2a and hand2 in the pharyngeal arches 3–6 are observed in CRISPR mutant and morphant embryos that are deficient in both zebrafish pax1a and pax1b at 96 or 36 hpf. These results suggest that zebrafish Pax1a and Pax1b both regulate pharyngeal pouch morphogenesis by modulating expression of fgf3 and tbx1. Furthermore, our data support a model wherein endodermal Pax1a and Pax1b act through Fgf3 and Tbx-Edn1 signaling to non-autonomously regulate the development of ceratobranchial cartilage via expression of dlx2a and hand2.

HAND2 TRANSCRIPTION FACTOR ENHANCES NMJ ORGANIZATION AND FUNCTION IN OLD MICE

Over time, declining muscle force and power leads to mobility disability and impaired quality of life. In aging rodents and humans, a denervation and reinnervation process is strongly implicated in sarcopenia: the progressive decline of skeletal muscle mass, composition, and function. We propose that the concomitant decline in expression of Hand2, a key transcription factor (TF) for sympathetic neuron maintenance, induces motor pre- and postsynaptic neuromuscular junction (NMJ) instability and disorganization. To counter the deleterious effect of sympathetic denervation, we developed a novel viral vector (AAV9-Hand2-eGFP, Hand2) carrying Hand2 expression exclusively to sympathetic neurons. Male and female, 16-month-old mice, were examined for signs of muscle denervation and sarcopenia 6 months after IV injection with either Hand2 or control empty virus (AAV9-eGFP, EV). We found that Hand2 increased preterminal synaptic vesicle release, neurofilament phosphorylation (Neurite length: Hand2: 3732±496 µm, EV: 2674±165 µm; P <0.01), NMJ pre/postterminal co-localization, hindlimb muscle mass (EDL: 25%, soleus: 14%, tibialis anterior: 17% and gastrocnemius: 25%; n = 6-8 muscles per treatment group; P < 0.01), myofiber cross-sectional area, and protein kinase-A RIIα/RIα ratio (EV, RIIα:1.05±0.03, RIα:0.93±0.04, ratio: 1.13; Hand2, RIIα:1.81±0.03, RIα:0.94±0.03, ratio: 1.94; P<0.001) which contributes to stability of the NMJ. We also examined Hand2 gene methylation, and RNA-sequencing, muscle metabolomics, and whole body and muscle function with aging in EV and Hand2 injected mice. Our data indicate that expression of Hand2 significantly enhances skeletal muscle adrenergic receptor signaling through the canonical pathway, and prevents in NMJ transmission, and muscle mass and function decline with aging.

Heart and Neural Crest Derivatives Expressed Transcript 2 (HAND2) is Reduced in Women with Breast Cancer. A Case-Control Study

Background: The search for new markers for breast cancer (BC) has been sought in order to better understand this type of cancer. The Heart and Neural Crest Derivatives Expressed Transcript 2 (HAND2) has been related to endometrial cancer but there are scant data related to BC. The aim of this study is to compare the immunohistochemical expression of HßAND2 in normal breast tissue vs. BC and to correlate with the estrogen receptor (ERα). Patients and Methods: In this case-control study, 19 formalin–fixed, paraffin-embedded tissues were obtained from pathological archives. Benign (n=9; control) and cancer (n=10) breast tissue were analyzed with immunohistochemistry for HAND2 (Ab60037), at dilution 1:50 at pH 9 and ERα (SP1). ImageJ software with "color deconvolution" was used for analysis of the expression of these proteins. The sample size was calculated (power=95%, α error= 1%) to identify an increase from mean 15 DAB units (control) to 40 DAB units in cancer. Results: HAND2 expression (mean ± SD) was 15.5 ± 6.1 (cancer) versus 44.8 ± 21.1 (control) (P=0.002, Student t-test). Its expression was mainly present in the cytosol of the cells. No correlation was observed between ERα and HAND2 (Pearson r = -0.28 (95%CI=-0.6 to 0.22; P=0.2). Conclusions: The protein expression of HAND2, using Ab60037 antibody, is reduced in breast cancer, compared with normal breast tissue. The expression of HAND2 is not correlated with ERα expression.