- Browse by Subject
Browsing by Subject "Neural crest"
Now showing 1 - 8 of 8
Results Per Page
Sort Options
Item Hand1 phosphoregulation within the distal arch neural crest is essential for craniofacial morphogenesis(The Company of Biologists, 2014-08) Firulli, Beth A.; Fuchs, Robyn K.; Vincentz, Joshua W.; Clouthier, David E.; Firulli, Anthony B.; Department of Pediatrics, IU School of MedicineIn this study we examine the consequences of altering Hand1 phosphoregulation in the developing neural crest cells (NCCs) of mice. Whereas Hand1 deletion in NCCs reveals a nonessential role for Hand1 in craniofacial development and embryonic survival, altering Hand1 phosphoregulation, and consequently Hand1 dimerization affinities, in NCCs results in severe mid-facial clefting and neonatal death. Hand1 phosphorylation mutants exhibit a non-cell-autonomous increase in pharyngeal arch cell death accompanied by alterations in Fgf8 and Shh pathway expression. Together, our data indicate that the extreme distal pharyngeal arch expression domain of Hand1 defines a novel bHLH-dependent activity, and that disruption of established Hand1 dimer phosphoregulation within this domain disrupts normal craniofacial patterning.Item Hand2 function within non-cardiomyocytes regulates cardiac morphogenesis and performance(2014) VanDusen, Nathan J.; Firulli, Anthony B.; Herbert, Brittney-Shea; Mayo, Linda D.; Shou, WeinianThe heart is a complex organ that is composed of numerous cell types, which must integrate their programs for proper specification, differentiation, and cardiac morphogenesis. During cardiac development the basic helix-loop-helix transcription factor Hand2 is dynamically expressed within the endocardium and extra-cardiac lineages such as the epicardium, cardiac neural crest cells (cNCCs), and NCC derived components of the autonomic nervous system. To investigate Hand2 function within these populations we utilized multiple murine Hand2 Conditional Knockout (H2CKO) genetic models. These studies establish for the first time a functional requirement for Hand2 within the endocardium, as several distinct phenotypes including hypotrabeculation, tricuspid atresia, aberrant septation, and precocious coronary development are observed in endocardial H2CKOs. Molecular analyses reveal that endocardial Hand2 functions within the Notch signaling pathway to regulate expression of Nrg1, which encodes a crucial secreted growth factor. Furthermore, we demonstrate that Notch signaling regulates coronary angiogenesis via Hand2 mediated modulation of Vegf signaling. Hand2 is strongly expressed within midgestation NCC and endocardium derived cardiac cushion mesenchyme. To ascertain the function of Hand2 within these cells we employed the Periostin Cre (Postn-Cre), which marks cushion mesenchyme, a small subset of the epicardium, and components of the autonomic nervous system, to conditionally ablate Hand2. We find that Postn-Cre H2CKOs die shortly after birth despite a lack of cardiac structural defects. Gene expression analyses demonstrate that Postn-Cre ablates Hand2 from the adrenal medulla, causing downregulation of Dopamine Beta Hydroxylase (Dbh), a gene encoding a crucial catecholaminergic biosynthetic enzyme. Electrocardiograms demonstrate that 3-day postnatal Postn-Cre H2CKO pups exhibit significantly slower heart rates than control littermates. In conjunction with the aforementioned gene expression analyses, these results indicate that loss of Hand2 function within the adrenal medulla results in a catecholamine deficiency and subsequent heart failure.Item Insights into the genetic architecture of the human face(Springer Nature, 2021) White, Julie D.; Indencleef, Karlijne; Naqvi, Sahin; Eller, Ryan J.; Hoskens, Hanne; Roosenboom, Jasmien; Lee, Myoung Keun; Li, Jiarui; Mohammed, Jaaved; Richmond, Stephen; Quillen, Ellen E.; Norton, Heather L.; Feingold, Eleanor; Swigut, Tomek; Marazita, Mary L.; Peeters, Hilde; Hens, Greet; Shaffer, John R.; Wysocka, Joanna; Walsh, Susan; Weinberg, Seth M.; Shriver, Mark D.; Claes, Peter; Biology, School of ScienceThe human face is complex and multipartite, and characterization of its genetic architecture remains challenging. Using a multivariate genome-wide association study meta-analysis of 8,246 European individuals, we identified 203 genome-wide-significant signals (120 also study-wide significant) associated with normal-range facial variation. Follow-up analyses indicate that the regions surrounding these signals are enriched for enhancer activity in cranial neural crest cells and craniofacial tissues, several regions harbor multiple signals with associations to different facial phenotypes, and there is evidence for potential coordinated actions of variants. In summary, our analyses provide insights into the understanding of how complex morphological traits are shaped by both individual and coordinated genetic actions.Item Leukocyte Tyrosine Kinase ( Ltk) Is the Mendelian Determinant of the Axolotl Melanoid Color Variant(MDPI, 2023-04-13) Kabangu, Mirindi; Cecil, Raissa; Strohl, Lloyd, II; Timoshevskaya, Nataliya; Smith, Jeramiah J.; Voss, Stephen R.; Medicine, School of MedicineThe great diversity of color patterns observed among amphibians is largely explained by the differentiation of relatively few pigment cell types during development. Mexican axolotls present a variety of color phenotypes that span the continuum from leucistic to highly melanistic. The melanoid axolotl is a Mendelian variant characterized by large numbers of melanophores, proportionally fewer xanthophores, and no iridophores. Early studies of melanoid were influential in developing the single-origin hypothesis of pigment cell development, wherein it has been proposed that all three pigment cell types derive from a common progenitor cell, with pigment metabolites playing potential roles in directing the development of organelles that define different pigment cell types. Specifically, these studies identified xanthine dehydrogenase (XDH) activity as a mechanism for the permissive differentiation of melanophores at the expense of xanthophores and iridophores. We used bulked segregant RNA-Seq to screen the axolotl genome for melanoid candidate genes and identify the associated locus. Dissimilar frequencies of single-nucleotide polymorphisms were identified between pooled RNA samples of wild-type and melanoid siblings for a region on chromosome 14q. This region contains gephyrin (Gphn), an enzyme that catalyzes the synthesis of the molybdenum cofactor that is required for XDH activity, and leukocyte tyrosine kinase (Ltk), a cell surface signaling receptor that is required for iridophore differentiation in zebrafish. Wild-type Ltk crispants present similar pigment phenotypes to melanoid, strongly implicating Ltk as the melanoid locus. In concert with recent findings in zebrafish, our results support the idea of direct fate specification of pigment cells and, more generally, the single-origin hypothesis of pigment cell development.Item A retrospective analysis of comorbid traits affecting feeding in infants with Down syndrome(2012-07-03) Duvall, Nichole L.; Roper, Randall J.; Marrs, Kathleen A.; Chernoff, EllenDown syndrome (DS) is the most common aneuploidy to affect humans and occurs in approximately 1 of 750 live births. Individuals with DS present with a wide range of clinical phenotypes. Common craniofacial phenotypic expressions include a small mandible, protruding tongue, and a flattened nasal bridge. These traits may affect the feeding, breathing, and swallowing of individuals with DS. Because some complications may go unnoticed for longer periods of time, we hypothesize that significant cardiac and GI defects may be indicative of feeding and airway difficulties. In order to better understand the secondary phenotypes resulting from DS, we have implemented a retrospective chart review of 137 infants between zero and six months of age who were evaluated through the Down Syndrome Program at Riley Hospital for Children from August 2005 to August 2008. Data regarding cardiac, gastrointestinal, endocrine, airway, auditory, and feeding abnormalities have been collected and incedences and comorbidites of these traits has been examined. Comprehensive results indicate cardiac abnormalities occur in 80% of infants, 60% experience gastrointestinal complications, feeding difficulties occur in 46%, and airway complications occur in 38% of infants. Infants with DS were found to be breastfed less over time, with an increase in tube feeds. Notably, we have found all infants with videofluoroscopic evaluations had some type of dysphagia. The presence of gastrointestinal abnormalities closely correlate with the need for tube feeds, and the comorbidity between GI anomalies and muscle tone appear to indicate the likelihood of feeding difficulties and need for altered feeding strategies. Comorbidities between feeding difficulties were nearly significant with cardiac defects and significant with GI abnormalities. Identification of such associations will help healthcare providers determine the best course of treatment and recommended feeding methodology for infants with DS. In order to utilize an in vitro model to study the craniofacial dysmorphologies seen in individuals with DS, cranial neural crest cells (NC) have been cultured. With these, we have begun to investigate the mechanisms behind a smaller trisomic mandibular precursor as compared to the euploid. With this in vitro model, we will be able to test proliferation, migration, and senescence of NC in a culture system.Item Transgenic use of SMAD7 to suppress TGFß signaling during mouse development(2010-10-21) Tang, Sunyong; Conway, Simon J.; Harrington, Maureen A.; Skalnik, David Gordon; Rhodes, Simon J.Neural crest cells (NCC) are a multipotent population of cells that form at the dorsal region of neural tube, migrate and contribute to a vast array of embryonic structures, including the majority of the head, the septum of the cardiac outflow tract (OFT), smooth muscle subpopulations, sympathetic nervous system and many other organs. Anomalous NCC morphogenesis is responsible for a wide variety of congenital defects. Importantly, several individual members of the TGFβ superfamily have been shown to play essential roles in various aspects of normal NCC development. However, it remains unclear what role Smad7, a negative regulator of TGFβ superfamily signaling, plays during development and moreover what the spatiotemporal effects are of combined suppression of TGFβ superfamily signaling during NCC formation and colonization of the developing embryo. Using a cre/loxP three-component triple transgenic system, expression of Smad7 was induced via doxycycline in the majority of pre- and post-migratory NCC lineages (via Wnt1-Cre mice). Further, expression of Smad7 was induced via doxycycline in a subset of post-migratory NCC lineages (via Periostin-Cre mice, after the NCC had reached their target organs and undergone differentiation). Induction of Smad7 within NCC significantly suppressed TGFβ superfamily signaling, as revealed via diminished phosphorylation levels of both Smad1/5/8 and Smad2/3 in vivo. This resulted in subsequent loss of NCC-derived craniofacial, pharyngeal and cardiac OFT cushion tissues. ROSA26r NCC lineage mapping demonstrated that cardiac NCC emigration and initial migration were unaffected, but subsequent colonization of the OFT was significantly reduced. At the cellular level, increased cell death was observed, but cell proliferation and NCC-derived smooth muscle differentiation were unaltered. Molecular analysis demonstrated that Smad7 induction resulted in selective increased phospho-p38 levels, which in turn resulted in the observed initiation of apoptosis in trigenic mutant embryos. Taken together, these data demonstrate that tightly regulated TGFβ superfamily signaling is essential for normal craniofacial and cardiac NCC colonization and cell survival in vivo.Item Treatment and genetic analysis of craniofacial deficits associated with down syndrome(2014-12-12) Tumbleson, Danika M.; Roper, Randall J.; Belecky-Adams, Teri; Yost, Robert; Picard, RobertDown syndrome (DS) is caused by trisomy of human chromosome 21 (Hsa21) and occurs in ~1 of every 700 live births. Individuals with DS present craniofacial abnormalities, specifically an undersized, dysmorphic mandible which may lead to difficulty with eating, breathing, and speech. Using the Ts65Dn DS mouse model, which mirrors these phenotypes and contains three copies of ~50% Hsa21 homologues, our lab has traced the mandibular deficit to a neural crest cell (NCC) deficiency in the first pharyngeal arch (PA1 or mandibular precursor) at embryonic day 9.5 (E9.5). At E9.5, the PA1 is reduced in size and contains fewer cells due to fewer NCC populating the PA1 from the neural tube (NT) as well as reduced cellular proliferation in the PA1. We hypothesize that both the deficits in NCC migration and proliferation may cause the reduction in size of the PA1. To identify potential genetic mechanisms responsible for trisomic PA1 deficits, we generated RNA-sequence (RNA-seq) data from euploid and trisomic E9.25 NT and E9.5 PA1 (time points occurring before and after observed deficits) using a next-generation sequencing platform. Analysis of RNA-seq data revealed differential trisomic expression of 53 genes from E9.25 NT and 364 genes from E9.5 PA1, five of which are present in three copies in Ts65Dn. We also further analyzed the data to find that fewer alternative splicing events occur in trisomic tissues compared to euploid tissues and in PA1 tissue compared to NT tissue. In a subsequent study, to test gene-specific treatments to rescue PA1 deficits, we targeted Dyrk1A, an overexpressed DS candidate gene implicated in many DS phenotypes and predicted to cause the NCC and PA1 deficiencies. We hypothesize that treatment of pregnant Ts65Dn mothers with Epigallocatechin gallate (EGCG), a known Dyrk1A inhibitor, will correct NCC deficits and rescue the undersized PA1 in trisomic E9.5 embryos. To test our hypothesis, we treated pregnant Ts65Dn mothers with EGCG from either gestational day 7 (G7) to G8 or G0 to G9.5. Our study found an increase in PA1 volume and NCC number in trisomic E9.5 embryos after treatment on G7 and G8, but observed no significant improvements in NCC deficits following G0-G9.5 treatment. We also observed a developmental delay of embryos from trisomic mothers treated with EGCG from G0-G9.5. Together, these data show that timing and sufficient dosage of EGCG treatment is most effective during the developmental window the few days before NCC deficits arise, during G7 and G8, and may be ineffective or harmful when administered at earlier developmental time points. Together, the findings of both studies offer a better understanding of potential mechanisms altered by trisomy as well as preclinical evidence for EGCG as a potential prenatal therapy for craniofacial disorders linked to DS.Item Two-Step Induction of Trabecular Meshwork Cells from Induced Pluripotent Stem Cells for Glaucoma(Elsevier, 2020-08-20) Kumar, Ajay; Cheng, Tianyu; Song, Weitao; Cheuk, Brandon; Yang, Enzhi; Yang, Lei; Xie, Yubing; Du, Yiqin; Pediatrics, School of MedicineGlaucoma is a leading cause of irreversible blindness worldwide. Reducing intraocular pressure is currently the only effective treatment. Elevated intraocular pressure is associated with increased resistance of the outflow pathway, mainly the trabecular meshwork (TM). Despite great progress in the field, the development of novel and effective treatment for glaucoma is still challenging. In this study, we reported that human induced pluripotent stem cells (iPSCs) can be cultured as colonies and monolayer cells expressing OCT4, alkaline phosphatase, SSEA4 and SSEA1. After induction to neural crest cells (NCCs) positive to NGFR and HNK1, the iPSCs can differentiate into TM cells. The induced iPSC-TM cells expressed TM cell marker CHI3L1, were responsive to dexamethasone treatment with increased expression of myocilin, ANGPTL7, and formed CLANs, comparable to primary TM cells. To the best of our knowledge, this is the first study that induces iPSCs to TM cells through a middle neural crest stage, which ensures a stable NCC pool and ensures the high output of the same TM cells. This system can be used to develop personalized treatments using patient-derived iPSCs, explore high throughput screening of new drugs focusing on TM response for controlling intraocular pressure, and investigate stem cell-based therapy for TM regeneration.