Cells Of Neural Crest Origin Research Articles

Retroperitoneal Ganglioneuroma Incidentally Found in a Patient Presenting with Renal Colic

A 21-year-old man with no significant past medical history presented to the emergency department with sudden-onset left upper and lower quadrant pain, which he described as being sharp and nonradiating. He also complained of nausea and dry heaves. Examination revealed left lower quadrant and left flank pain on palpation with slight protrusion of the left flank. There were no palpable masses. Urinalysis revealed 3+ blood. Computed tomography (CT) of the abdomen revealed a 2 mm obstructing stone in the distal left ureter (not shown), which was likely the source of the patient's pain, and a heterogenous mass in the retroperitoneum centered within the mesenteric root containing multiple coarse internal calcific deposits (Figure ​(Figure11). The mass was relatively well circumscribed and encased the inferior mesenteric artery without appreciable extrinsic mass effect (Figures ​(Figures22 and ​and33). The mass was subsequently biopsied by CT guidance, and histopathology was consistent with a ganglioneuroma (Figure ​(Figure44). The neoplasm was resected in its entirety. Figure 1 Axial noncontrast CT image demonstrates an oval mass in the retroperitoneum (short arrows) containing multiple coarse internal calcific deposits (long arrow). The internal attenuation of the mass is slightly less than that of the visualized musculature, ... Figure 2 Axial postcontrast CT image shows the well-circumscribed nature of the mass (red arrows). The mass is seen anterior to the abdominal aorta (yellow arrow) and inferior vena cava (dotted yellow arrow). The portal venous phase of the contrast demonstrates ... Figure 3 Coronal postcontrast images through the mass better delineate the encasement of the inferior mesenteric artery from its origin (arrows) without luminal compromise. Again seen is the well-circumscribed nature of the mass and internal calcific deposits. ... Figure 4 Photomicrographs of the specimen showing (a) a prominent background of wavy collagen fibers and Schwann cells and (b) mature ganglion cells (arrow), consistent with a ganglioneuroma. Ganglioneuromas are a rare neoplasm of neural crest cell origin. They are typically benign but can undergo malignant trasnformation in rare instances. The retroperitoneum and posterior mediastinum are the two most common locations for a ganglioneuroma. Patients of all ages are affected, but it is classically seen in adolescents and young adults. Patients are usually asymptomatic but can present with vague abdominal pain. Prognosis is usually excellent after complete surgical excision of the mass.

Dermal Stem Cells Can Differentiate Down an Endothelial Lineage

In this study, we have demonstrated that cells of neural crest origin located in the dermal papilla (DP) exhibit endothelial marker expression and a functional activity. When grown in endothelial growth media, DP primary cultures upregulate expression of vascular endothelial growth factor receptor 1 (FLT1) mRNA and downregulate expression of the dermal stem cell marker α-smooth muscle actin. DP cells have demonstrated functional characteristics of endothelial cells, including the ability to form capillary-like structures on Matrigel, increase uptake of low-density lipoprotein and upregulate ICAM1 (CD54) in response to tumour necrosis factor alpha (TNF-α) stimulation. We confirmed that these observations were not due to contaminating endothelial cells, by using DP clones. We have also used the WNT1cre/ROSA26R and WNT1cre/YFP lineage-tracing mouse models to identify a population of neural crest-derived cells in DP cultures that express the endothelial marker PECAM (CD31); these cells also form capillary-like structures on Matrigel. Importantly, cells of neural crest origin that express markers of endothelial and mesenchymal lineages exist within the dermal sheath of the vibrissae follicle.

Reelin signalling in neuroblastoma: Migratory switch in metastatic stages

The essential functions of Reelin for the migratory behaviour of neuroblasts in the central nervous system are well documented. Its role in the dissemination of neuronal tumours of the peripheral nervous system has not been studied in detail. Here, we examined neuroblastoma (NB), a tumour derived from sympathoadrenal cells of neural crest origin. We studied the expression of Reelin, its receptors VLDLR and LRP8 and the adapter protein DAB1 in primary tumour samples and cell lines. We used real-time RT-PCR, immunohistology and western blot analysis. In NB cell lines we studied effects of all-trans retinoic acid and the in vitro effects of Reelin. In primary tumour samples of untreated patients, a significant downregulation of Reelin and DAB1 mRNA was found in the metastatic stages 3, 4 and 4s. Immunohistochemical studies revealed expression of Reelin, LRP8 and DAB1 in differentiating-type low-grade NB. In vitro, western blot analysis of selected NB cell lines showed variable expression patterns. Differentiation induction with all-trans retinoic acid induced the upregulation of Reelin and DAB1. Reelin acted as a chemoattractant for various NB cell lines but inhibited migration when applied together with the NB cells. In normal tissue, we found Reelin in lymphatic endothelial cells (LECs) but not in blood vessel endothelium (BECs). In primary NB, both BECs and LECs were positive. Our data strongly suggest that Reelin has a dual role in NB. Autocrine expression marks low-grade differentiating tumour cells, whereas paracrine Reelin presented by LECs and BECs may act as a chemoattractant and promote hematogenic and lymphogenic dissemination in progressed stages.

Concise Review: Stem Cells in the Corneal Stroma

The cornea is a tough transparent tissue admitting and focusing light in the eye. More than 90% of the cornea is stroma, a highly organized, transparent connective tissue maintained by keratocytes, quiescent mesenchymal cells of neural crest origin. A small population of cells in the mammalian stroma displays properties of mesenchymal stem cells, including clonal growth, multipotent differentiation, and expression of an array of stem cell-specific markers. Unlike keratocytes, the corneal stromal stem cells (CSSCs) undergo extensive expansion in vitro without loss of the ability to adopt a keratocyte phenotype. Several lines of evidence suggest CSSCs to be of neural crest lineage and not from bone marrow. CSSCs are localized in the anterior peripheral (limbal) stroma near to stem cells of the corneal epithelium. CSSCs may function to support potency of the epithelial stem cells in their unique limbal niche. On the other hand, little information is available documenting a role for CSSCs in vivo in stromal wound healing or regeneration. In vitro CSSCs reproduce the highly organized connective tissue of the stroma, demonstrating a potential use of these cells in tissue bioengineering. Direct introduction of CSSCs into the corneal stroma generated transparent tissue in a mouse model of corneal opacity. Human CSSCs injected into mice corneas did not elicit immune rejection over an extended period of time. The CSSCs therefore appear offer an opportunity to develop cell- and tissue-based therapies for irreversible corneal blindness, conditions affecting more than 10 million individuals worldwide.

Aebp2 as an Epigenetic Regulator for Neural Crest Cells

Aebp2 is a potential targeting protein for the mammalian Polycomb Repression Complex 2 (PRC2). We generated a mutant mouse line disrupting the transcription of Aebp2 to investigate its in vivo roles. Aebp2-mutant homozygotes were embryonic lethal while heterozygotes survived to adulthood with fertility. In developing mouse embryos, Aebp2 is expressed mainly within cells of neural crest origin. In addition, many heterozygotes display a set of phenotypes, enlarged colon and hypopigmentation, similar to those observed in human patients with Hirschsprung's disease and Waardenburg syndrome. These phenotypes are usually caused by the absence of the neural crest-derived ganglia in hindguts and melanocytes. ChIP analyses demonstrated that the majority of the genes involved in the migration and development process of neural crest cells are downstream target genes of AEBP2 and PRC2. Furthermore, expression analyses confirmed that some of these genes are indeed affected in the Aebp2 heterozygotes. Taken together, these results suggest that Aebp2 may regulate the migration and development of the neural crest cells through the PRC2-mediated epigenetic mechanism.

Abstract LB-233: Modeling Ewing sarcoma initiation in human neural crest stem cells

Abstract Ewing sarcoma family tumors (ESFT) are aggressive bone and soft tissue tumors of putative neural crest (NCSC) and/or mesenchymal (MSC) stem cell origin. It is our hypothesis that the initiation and progression of ESFT depends on aberrant silencing of genes that normally instruct terminal differentiation of NCSC and their progeny. Further, we hypothesize that this is a downstream consequence of EWS-FLI1-mediated activation of polycomb proteins. In the current study we are using human NCSC to define the consequences of EWS-FLI1 oncogene expression on DNA methylation in developing neural crest cells. NCSC were isolated from in vitro differentiating embryonic stem cells by FACS-based sorting. NCSC were expanded in culture in self-renewal media or induced to differentiate either as unmanipulated cells or following lentiviral transduction with EWS-FLI1-EGFP or EGFP control virus. Cells were studied for differentiation capacity and for gene expression by RT-PCR and Affymetrix Human Exon array profiling. Genomic DNA was isolated at various timepoints for evaluation of genome wide DNA methylation using Illumina 450K BeadChips. Our studies thus far show that clonal populations of NCSC can be induced to generate neural, glial and myofibroblastic progeny. In addition, NCSC rapidly adopt an MSC-like phenotype in adherent culture and these cells (NC-MSC) retain the ability to differentiate into peripherin positive peripheral nerves as well as adipogenic and osteogenic progeny. Both NCSC and NC-MSC tolerate EWS-FLI1 and expression of EWS-FLI1 in NC-MSC partially reactivates the more primitive NCSC genetic program. EWS-FLI1-expressing cells up-regulate expression of the polycomb proteins BMI-1 and EZH2 and avoid cellular senescence. Kinetic transcriptional evaluation of transduced cells revealed that changes in gene expression downstream of EWS-FLI1 are highly dynamic. In particular, with increasing passage, EWS-FLI1+ cells progressively down-regulate transcripts involved in neural differentiation. Preliminary Illumina GoldenGate assays revealed that the promoters of many polycomb target genes involved in neural differentiation are relatively hypermethylated in ESFT compared to normal adult tissues and stem cells. We are now performing Illumina 450K assays of differentiating NCSC in the presence or absence of EWS-FLI1 to define the consequences of oncogene activation on the normal evolution of DNA methylation over time. Updated data from these studies will be presented at the meeting. In summary, we have developed a human developmental model in which to study the the molecular mechanisms of EWS-FLI1-induced transformation. Our studies thus far suggest that ESFT is a stem cell tumor in which a single genetic mutation induces profound epigenetic changes that ultimately cooperate to induce tumor formation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-233. doi:10.1158/1538-7445.AM2011-LB-233

The Incidence of Syndrome of Inappropriate Antidiuretic Hormone Secretion in Patients with Esthesioneuroblastoma

Introduction: Esthesioneuroblastoma (ENB) is a rare malignancy of the nasal vault. It is thought to arise from olfactory stem cells of neural crest origin. The most common presenting symptoms include nasal obstruction, rhinorrhea, epistaxis, and headaches. Although ENB is rarely associated with inappropriate antidiuretic hormone secretion, that symptom has been previously described. Recently, two patients presented to our institution with a history of unexplained hyponatremia for several months before detection of ENB.

Induced in vitro differentiation of neural-like cells from human exfoliated deciduous teeth-derived stem cells

Stem cells from human exfoliated deciduous teeth (SHED) are highly proliferative, clonogenic and multipotent stem cells with a neural crest cell origin. Additionally, they can be collected with minimal invasiveness in comparison with other sources of mesenchymal stem cells (MSCs). Therefore, SHED could be a desirable option for potential therapeutic applications. In this study, SHEDs were established from enzyme-disaggregated deciduous dental pulp obtained from 6 to 9 year-old children. The cells had typical fibroblastoid morphology and expressed antigens characteristic of MSCs, STRO1, CD146, CD45, CD90, CD106 and CD166, but not the hematopoietic and endothelial markers, CD34 and CD31, as assessed by FACS analysis. Differentiation assessment revealed a strong osteogenic and adipogenic potential of SHEDs. In order to further evaluate the in vitro differentiation potential of SHED into neural cells, a simple short time growth factor-mediated induction was used. Immunofluorescence staining and flow cytometric analysis revealed that SHED rapidly expressed nestin and b-III tubulin, and later expressed intermediate neural markers. In addition, the intensity and percentages of nestin and b-III tubulin and mature neural markers (PSA-NCAM, NeuN, Tau, TH, or GFAP) increased significantly following treatment. Moreover, RT-PCR and Western blot analyses showed that the neural markers were strongly up-regulated after induction. In conclusion, these results provide evidence that SHED can differentiate into neural cells by the expression of a comprehensive set of genes and proteins that define neural-like cells in vitro. SHED cells might be considered as new candidates for the autologous transplantation of a wide variety of neurological diseases and neurotraumatic injuries.

Origins of Gliogenic Stem Cell Populations Within Adult Skin and Bone Marrow

The generation of Schwann cells from precursors within adult skin and bone marrow is of significant clinical interest because of the opportunities for disease modelling and strategies for remyelination. Recent evidence has suggested that glial cells can be generated from (i) mesenchymal stem cells (MSCs) within adult bone marrow and (ii) skin-derived precursor cells (SKPs) within adult skin. However, there is a need to clarify the developmental mechanism whereby such multipotent adult stem cell populations generate glia. We used Wnt1-Cre/Rosa26R(LacZ) and Wnt1-Cre/Rosa26R(YFP) neural crest reporter mice to test the hypothesis that (i) MSCs and (ii) SKPs represent adult gliogenic precursor cells of neural crest origin. We demonstrate that, although labeled cells can be identified within long bone preparation, such cells are rarely found in marrow plugs. Moreover, we did not find evidence of a neural crest origin of bone marrow-derived MSCs and were not able to provide a developmental rationale for the derivation of glial cells from MSCs using this approach. In contrast, we provide robust evidence for the neural crest origin of SKPs derived from adult skin. These precursor cells reliably generate cells with a Schwann cell phenotype, expressing appropriate transcription factors and Schwann cell markers. We demonstrate multiple anatomical origins of gliogenic SKPs within adult skin. We conclude that SKPs, rather than bone marrow-derived MSCs, represent a more defined and developmentally rational source for the study and generation of Schwann cells from readily accessible adult tissues.

Optimizing Orthotopic Cell Transplantation in the Mouse Adrenal Gland

Orthotopic cell transplantation models are important for a complete understanding of cell-cell interactions as well as tumor biology. In published studies of orthotopic transplantation in the mouse adrenal gland, human neuroblastoma cells have been shown to invade and occupy the adrenal, but in these investigations a true orthotopic model was not established. Here we show an orthotopic model in which transplanted cells are retained within the adrenal gland by formation of a fibrin clot. To establish an appropriate technique, we used brightly fluorescent 10 microm polystyrene microspheres injected into the mouse adrenal gland. In the absence of fibrinogen/thrombin for clot formation, much of the injected material was extruded to the outside of the gland. When the microspheres were injected in a fibrinogen/thrombin mixture, fluorescence was confined to the adrenal gland. As a model neoplastic cell originating from the cortex of the gland, we used a tumorigenic bovine adrenocortical cell line. When 3 x 10(5) cells were implanted orthotopically, by 16 days the cell mass had expanded and had invaded the cortex, whereas when 1 x 10(5) cells were used, tumor masses were much smaller. We therefore subsequently used 3 x 10(5) cells. When mice were sacrificed at different time points, we found that tumor growth resulting was progressive and that by 26 days cells there was extensive invasion into the cortex or almost complete replacement of the cortex with tumor cells. As a model neoplastic cell of neural crest origin, we used SK-N-AS human neuroblastoma cells. Orthotopic transplantation of 3 x 10(5) cells resulted in extensive invasion and destruction of the gland by 26 days. In summary, the present orthotopic model for intra-adrenal cell transplantation is valuable for investigation of growth of neoplastic cells of both cortical and medullary origin and should be useful for future studies of cortex-medulla interactions.

Neural Crest Cell Origin and Signals for Intrinsic Neurogenesis in the Mammalian Respiratory Tract

Our study investigates the innervation of the respiratory tract during mouse embryonic development, with a focus on the identification of cell origin and essential developmental signals for the resident, or intrinsic, neurons. Using lineage tracing, we show that these intrinsic neurons are exclusively derived from neural crest cells, and cluster to form ganglia that reside in the dorsal trachea and medial bronchi with diminishing frequency. Comparisons of intrinsic neurogenesis between wild-type, glial cell-derived neurotrophic factor (GDNF)(-/-), neurturin(-/-), and tyrosine kinase receptor Ret(-/-) embryos, in combination with lung organ cultures, identified that Ret signaling, redundantly activated by GDNF family members, is required for intrinsic neurogenesis in the trachea and primary bronchi. In contrast, Ret deficiency exerts no effect on the innervation of the rest of the respiratory tract, suggesting that innervation by neurons whose cell bodies are located outside of the lung (so-called extrinsic neurons) is independent of Ret signaling. Furthermore, although the trachea, the esophagus, and their intrinsic neurons share foregut endoderm and a neural crest cell origin, respectively, the signals required for their intrinsic neurogenesis are divergent. Together, our results not only establish the neural crest lineage of intrinsic neurons in the respiratory tract, but also identify regional differences in the abundance and developmental signals of intrinsic neurons along the respiratory tract and in the esophagus.

Meckel’s Cartilage: Discovery, Embryology and Evolution

Meckel’s cartilage, discovered by German anatomist J. F. Meckel (1781-1833), is hyaline cartilage formed in the mandibular process of the first branchial arch of vertebrate embryos. An intermediate portion of Meckel’s cartilage is absorbed by multinucleated cells and disappears during the following developmental stages in mammals. The process of Meckel’s cartilage disappearance is not accompanied by the apoptosis of chondrocytes. The most posterior portion of the cartilage is changed to auditory ossicles by endochondral ossification, and the rest of the posterior portion transdifferentiates into sphenomandibular ligament. Meckel’s cartilage is not considered an anlage of the mandible, since bony tissue of the mandible is independently formed by membranous ossification. Chondrocytes are differentiated from mesodermal cells in general, whereas cells forming Meckel’s cartilage are differentiated from ectodermal mesenchymal cells of neural crest origin. In reptiles, Meckel’s cartilage ossifies and forms bone in the lower jaws, and cretaceous mammals had calcified Meckel’s cartilage in addition to a mandible. During the evolution from reptile to mammal, the mode of mastication changed, and the origin of bone in the lower jaw may have been gradually transferred from Meckel’s cartilage to the mandible.

Age-dependent changes in the gut environment restrict the invasion of the hindgut by enteric neural progenitors

The enteric nervous system (ENS) develops from neural crest cells (NCCs) that enter the foregut and hindgut to become enteric neural-crest-derived cells (ENCCs). When these cells of neural crest origin fail to colonize the terminal hindgut, this aganglionic region becomes non-functional and results in a condition in humans known as Hirschsprung's disease (HSCR). One of the genes associated with HSCR is endothelin receptor type B (Ednrb). To study the development of colonic aganglionosis we have utilized a novel knockout mouse (Ednrb(flex3/flex3)), in which the expression of a null Ednrb allele and YFP is confined to NCCs. We have identified two primary cellular defects related to defective EDNRB signaling. First, ENCC advance in Ednrb(flex3/flex3) embryos is delayed shortly after NCCs enter the gut. Apart from this early delay, Ednrb(flex3/flex3) ENCCs advance normally until reaching the proximal colon. Second, as Ednrb(flex3/flex3) ENCCs reach the colon at E14.5, they display migratory defects, including altered trajectories and reduced speed, that are not dependent on proliferation or differentiation. We constructed grafts to test the ability of donor ENCCs to invade a recipient piece of aganglionic colon. Our results indicate that the age of the recipient, and not the age or genotype of donor ENCCs, determines whether the colon is invaded. We identify changes in laminin expression that are associated with the failure of ENCCs to invade recipient tissue. Together, our data suggest that a defect in pre-enteric Ednrb(flex3/flex3) NCCs results in delayed colonic arrival, which, due to environment changes in the colon, is sufficient to cause aganglionosis.

Characterization of human epidermal neural crest stem cell (hEPI‐NCSC) candidate cells

We provide the first comprehensive characterization of hEPI‐NCSC candidate cells. Mouse EPI‐NCSC are multipotent remnants of the embryonic neural crest in a postnatal location, the bulge of hair follicles. Here, the bulge region of human anagen hair follicles was micro‐dissected from pubic skin that was procured with informed consent after elective Caesarean section. Emigrating cells were multipotent, as progeny of clone‐forming cells differentiated into smooth muscle cells, neuroblasts, and bone/cartilage cells. Gene expression profiling using the Illumina platform suggested that 17/18 mouse neural crest molecular signature genes identifiable in humans were also highly abundant in hEPI‐NCSC (PCBP4, MSX2, H1FX, PYGO2, THOP1, MYO10, ETS1, PYGO2, ADAM12, BEX1, VDAC1, CALR, CRYAB, PEG10 AGPAT6, CRMP1, UBE4B). Expression of eight of those genes, nestin and the neural crest marker SOX10, was validated by immunocytochemistry. Additional key neural crest‐characteristic genes included WNT1, SNAI2, MSX1, PAX9 and TNFRSF1B (p75NTR). The iPS genes MYC, KLF4, LIN28, and SOX2 were present at highly significant levels. Taken together, the data suggest that hEPI‐NCSC are multipotent cells of neural crest origin.

Schwannomas of the Left Adrenal Gland and Posterior Mediastinum

Schwannoma is a rare tumor of neural crest cell origin. Most schwannomas occur in the head, neck, stomach or limbs, with a few cases occurring in the retroperitoneal space. A 30-year-old Taiwanese woman presented with a 1-week history of left anterior chest discomfort and left flank pain. The laboratory findings and endocrine studies were all within normal limits. Chest X-ray revealed masses in the posterior mediastinum. Chest computed tomography and magnetic resonance imaging showed several masses in the left paraspinal region and in the left adrenal region. The patient underwent total excision of the left paraspinal tumors and laparoscopic left adrenalectomy. Pathologic studies showed a picture of benign schwannoma. In conclusion, preoperative differentiation of benign schwannoma from malignant peripheral nerve sheath tumor or other tumors is important for good prognosis. Total excision of benign schwannoma is associated with favourable outcome in patients.

Pheochromocytoma

Pheochromocytomas are catecholamine secreting tumors arising from the chromaffin cells of neural crest origin with prevalence of 0.1% to 0.6% in the hypertensive population. We describe our experience with 95 patients with pheochromocytoma from a tertiary care center in north India. Patients diagnosed with pheochromocytoma from 1996 to 2006 were studied. Details of the clinical manifestations, diagnostic workup including 24-hour urinary vanilyl mandelic acid (VMA) and/or urinary epinephrine (E) and norepinephrine (NE) along with localization modalities including ultrasonography (USG), CT scan of the abdomen, and meta-iodo benzyl guanidine scan were analyzed. Intraoperative details including fluctuation in blood pressure during surgery, size of the tumor, postoperative events, and follow-up records for the presence /resolution of hypertension, and recurrence of disease were also evaluated. A total of 95 patients (46 men), were diagnosed with pheochromocytoma during the study period. The mean age of these patients was 34 ± 15 years, and the lag time between the onset of symptoms and diagnosis was 2.5 ± 3.8 years. Eighty percent of the patients had an adrenal pheochromocytoma, whereas 19 (20%) were detected to have paraganglionomas. Two thirds of the patients were suspected to have pheochromocytoma because of hypertension and one of the components of paroxysmal triad. The rest were detected incidentally. Eighty-five patients (89%) were found to be hypertensive with 61 (72%) having sustained and 24 (28%) having labile hypertension. Elevated 24-hour urinary VMA and catecholamines (E/NE) were found in 41 (46%) and 37 (40%) patients. USG localized tumor in 88% and CT scan (adrenal or extra-adrenal) in 99% patients. Eighty-seven patients underwent surgical excision of the tumor. The mean tumor weight was 109 ± 193 g. Nine patients had malignancy as evidenced by distant metastases. At follow-up, 71% were normotensive with recurrence of disease in 11 patients including 9 with metastatic disease. The majority of patients with adrenal pheochromocytoma were young and one-third of them were detected incidentally. The paroxysmal triad was observed in two-thirds of the patients and majority of them had large tumors, which could even be localized by USG. Urinary VMA and catecholamines seems to be a poor tool for screening. Surgery was rewarding in that two thirds of the patients experienced resolution of hypertension.

A sonic hedgehog signaling domain in the arterial adventitia supports resident Sca1 + smooth muscle progenitor cells

We characterize a sonic hedgehog (Shh) signaling domain restricted to the adventitial layer of artery wall that supports resident Sca1-positive vascular progenitor cells (AdvSca1). Using patched-1 (Ptc1(lacZ)) and patched-2 (Ptc2(lacZ)) reporter mice, adventitial Shh signaling activity was first detected at embryonic day (E) 15.5, reached the highest levels between postnatal day 1 (P1) and P10, was diminished in adult vessels, and colocalized with a circumferential ring of Shh protein deposited between the media and adventitia. In Shh(-/-) mice, AdvSca1 cells normally found at the aortic root were either absent or greatly diminished in number. Using a Wnt1-cre lineage marker that identifies cells of neural crest origin, we found that neither the adventitia nor AdvSca1 cells were labeled in arteries composed of neural crest-derived smooth muscle cells (SMCs). Although AdvSca1 cells do not express SMC marker proteins in vivo, they do express transcription factors thought to be required for SMC differentiation, including serum response factor (SRF) and myocardin family members, and readily differentiate to SMC-like cells in vitro. However, AdvSca1 cells also express potent repressors of SRF-dependent transcription, including Klf4, Msx1, and FoxO4, which may be critical for maintenance of the SMC progenitor phenotype of AdvSca1 cells in vivo. We conclude that a restricted domain of Shh signaling is localized to the arterial adventitia and may play important roles in maintenance of resident vascular SMC progenitor cells in the artery wall.

Neuroendocrine carcinoma arising in soft tissue: three case reports and literature review

BackgroundNeuroendocrine tumours (NET) are tumours arising from neuroendocrine cells of neural crest origin. They are characterised by the presence of neurosecretory granules which react positively to silver stains and to specific markers including neuron specific enolase, synaptophysin and chromogranin. Metastasis to the skin occurs infrequently but primary soft tissue NET is excessively rare.Case presentationWe report our experience with 3 such cases. In the first case, the NET originated in muscle and was treated with wide surgical excision and adjuvant radiotherapy. The second case presented as a subcutaneous mass in the foot and the tumour was positive on 123I mIBG scan. She has had prolonged recurrence-free survival following primary hypo-fractionated radiotherapy. In the third case, a cutaneous nodule proved to be a NET and at surgery, lymph node disease was present. He has remained disease-free after surgical excision without the need for external beam radiotherapy.ConclusionThese tumours appear to have a good prognosis. Complete excision offers potentially curative treatment. Adjuvant radiotherapy may be helpful when the tumour margin is narrow. For patients with unresectable disease or where surgery would not be appropriate, radiotherapy appears to be an effective therapeutic option.

Malignant peripheral nerve sheath tumors

Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft tissue sarcomas of ectomesenchymal origin. The World Health Organization coined the term MPNST to replace previous heterogeneous and often confusing terminology, such as "malignant schwannoma," "malignant neurilemmoma," "neurogenic sarcoma," and "neurofibrosarcoma." Malignant peripheral nerve sheath tumors arise from major or minor peripheral nerve branches or sheaths of peripheral nerve fibers, and are derived from Schwann cells or pluripotent cells of neural crest origin. The Schwann cell is thought to be the major contributor to the formation of benign as well as malignant neoplasms of the nerve sheath. While this fact remains essentially true, the identity of cell of origin of the MPNST remains elusive, and has not yet been conclusively identified. It has been suggested that these tumors may have multiple cell line origins. In this review, the authors discuss the epidemiology, diagnosis, management, and treatment of MPNSTs.

Highly Efficient Neural Differentiation of Human Somatic Stem Cells, Isolated by Minimally Invasive Periodontal Surgery

Neural stem cells (NSCs) are potential sources for cell therapy of neurodegenerative diseases and for drug screening. Despite their potential benefits, ethical and practical considerations limit the application of NSCs derived from human embryonic stem cells (ES) or adult brain tissue. Thus, alternative sources are required to satisfy the criteria of ready accessibility, rapid expansion in chemically defined media and reliable induction to a neuronal fate. We isolated somatic stem cells from the human periodontium that were collected during minimally invasive periodontal access flap surgery as part of guided tissue regeneration therapy. These cells could be propagated as neurospheres in serum-free medium, which underscores their cranial neural crest cell origin. Culture in the presence of epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2) under serum-free conditions resulted in large numbers of nestin-positive/Sox-2-positive NSCs. These periodontium-derived (pd) NSCs are highly proliferative and migrate in response to chemokines that have been described as inducing NSC migration. We used immunocytochemical techniques and RT-PCR analysis to assess neural differentiation after treatment of the expanded cells with a novel induction medium. Adherence to substrate, growth factor deprivation, and retinoic acid treatment led to the acquisition of neuronal morphology and stable expression of markers of neuronal differentiation by more than 90% of the cells. Thus, our novel method might provide nearly limitless numbers of neuronal precursors from a readily accessible autologous adult human source, which could be used as a platform for further experimental studies and has potential therapeutic implications.