Search Results (337)

This is a narrative review that describes the evolution of terminology and classification schemes of neuroendocrine tumors (NETs), neuroendocrine carcinomas (NECs), mixed neuroendocrine–non-neuroendocrine neoplasms (MiNENs), and paragangliomas of the larynx, with the contribution of immunohistochemistry and treatment of neuroendocrine neoplasms of the larynx. Neuroendocrine neoplasms of the larynx comprise both epithelial (NET and NEC) and neural crest-derived (paraganglioma) neoplasms. Their terminology has evolved substantially over time, with current classifications emphasizing biologically and clinically meaningful categories aligned with contemporary WHO frameworks of other organs. These neoplasms may show overlapping clinical presentation and histomorphological features, which can complicate accurate subclassification. However, precise classification is essential, as these entities display markedly different biological behavior, ranging from indolent to highly aggressive with poor prognosis, and their treatment is essentially histology-tailored. Neuroendocrine neoplasms are classified into three categories comprising six tumor subtypes: well-differentiated neuroendocrine tumors (NETs; grades 1, 2, and 3), poorly differentiated neuroendocrine carcinomas (NECs; small-cell and large-cell types), and paragangliomas. An additional, not yet WHO-recognized category is MiNENs (mixed neuroendocrine–non-neuroendocrine neoplasms), defined by the coexistence of neuroendocrine and non-neuroendocrine components. These tumors exhibit distinct biological behavior and clinical significance. Full article

Neural crest cells give rise to the craniofacial skeleton and multiple pigment cell lineages, yet how duplicated developmental regulators partition their ancestral functions after teleost-specific whole-genome duplication remains unclear. Here, we employed CRISPR/Cas9 to generate alx4a and alx4b single and double mutants in Nile tilapia (Oreochromis niloticus). By integrating phenotype, skeleton, transcriptome, quantitative PCR, and AlphaFold-based structural modeling analyses, we revealed their functional divergence. Loss of alx4a caused a regionally restricted reduction in iridophore-derived reflectance and abnormal cranial morphology, whereas alx4b single mutants showed no obvious phenotype under the conditions examined. By contrast, double mutants exhibited an almost complete loss of iridophore-derived structural coloration and substantially more severe cranial defects, accompanied by reduced calcein labeling in the opercular region, consistent with altered cranial mineralization. Skin transcriptomic and quantitative PCR analyses revealed marked downregulation of pnp4a and tfec, which are associated with iridophore differentiation and coloration, whereas no significant expression differences were detected for the iridophore survival-related genes ltk and mpv17. AlphaFold2-assisted HDOCK protein–DNA modeling yielded more favorable docking metrics for Alx4a than for Alx4b with the pnp4a promoter, supporting a potential Alx4a–pnp4a promoter interaction that requires experimental validation. In contrast, no significant genotype-dependent differences were detected in the measured abundance of melanophores, xanthophores, or erythrophores, and no obvious difference in gross dorsal-fin spine formation was observed under the conditions examined. Together, these findings reveal unequal functional contributions of alx4a and alx4b, with alx4a acting as the dominant paralog in iridophore-associated structural coloration and both paralogs contributing unequally to cranial development, and support pnp4a as a candidate downstream gene associated with Alx4a activity. Full article

Brain-derived neurotrophic factor (BDNF) impacts parasympathetic nervous system function by increasing the excitability of cardioinhibitory parasympathetic neurons in the brainstem, ultimately lowering heart rate (HR) and heightening resting parasympathetic tone. Yet, whether BDNF and its high-affinity receptor—tropomyosin receptor kinase B (TrkB)—also act more distally, i.e., at the level of cholinergic-sensitive intrinsic cardiac ganglia (ICGs), remains unclear. Hence, we conducted morphological and functional studies in neural crest-specific BDNF knockout mice (ncBDNF KO), a model that selectively ablates BDNF signaling in neural crest-derived autonomic structures, including the intrinsic cardiac nervous system. ncBDNF mice exhibited a significant rise in resting heart rate with unchanged baseline contractile performance, thus supporting the role of endogenous BDNF in maintaining physiological parasympathetic restraint. When examining the ICGs, immunofluorescence analysis revealed a highly compartmentalized organization, with BDNF being predominantly confined to cholinergic neuronal somata and TrkB mainly clustered instead in S100-positive satellite glial cells, thus unveiling a previously unrecognized neuron–glia BDNF/TrkB ICG pattern. Next, we directly infused BDNF in Langendorff-perfused isolated WT mouse hearts and observed a rapid and reproducible bradycardic response that was abrogated by atropine but potentiated by neostigmine, hence attesting to the cholinergic nature of such bradycardia. Of note, BDNF maintained its positive inotropic effects under muscarinic blockade, as witnessed by the enhanced left ventricular developed pressure, maximal dP/dt, and rate-pressure product, congruent with direct BDNF-evoked myocardial TrkB agonism. Thus, ICGs are additional relevant relay stations interposed between BDNF/TrkB signaling and parasympathetic modulation of heart function. Although through different molecular paths, BDNF-mediated modulation of ICG firing can coordinate with the previously reported BDNF positive inotropy/lusitropy to adapt cardiac performance to increased workload and/or stress conditions. Full article

Ruminants are unique among living mammals in possessing paired bony cranial appendages in the form of horns, pronghorns, antlers, or ossicones. This review summarizes current knowledge on the structure, development, function, and evolution of these appendages and integrates recent findings from genomics, transcriptomics, and single-cell analyses. Two competing hypotheses have been proposed to explain their origin. According to the independent-origin hypothesis, horns, pronghorns, antlers, and ossicones evolved separately in different pecoran lineages, possibly through repeated recruitment of similar developmental capacities of the frontal region of the skull. According to the common-origin hypothesis, these appendages derive from a single ancestral osseous cranial structure that was subsequently modified in different lineages. Comparative anatomy and developmental data reveal major differences among the four types of appendages, including dermally ossifying horn cores in bovids, annually regenerated antlers arising from frontal bone pedicles in cervids, deciduous keratin sheaths in pronghorns, and skin-covered ossicones in giraffids. The fossil record does not currently resolve these hypotheses, because the main appendage types are first documented within a relatively short early Miocene interval and transitional forms remain unknown. In contrast, molecular and cellular studies identify shared developmental pathways, cranial neural crest-derived progenitors, and conserved regulatory genes, including RXFP2, ALX1, SOX9, and components of Wnt signaling, which are consistent with a shared developmental module. We conclude that the homology of pecoran cranial appendages remains unresolved and that further paleontological, developmental, and comparative molecular studies are required to determine whether these structures share a common evolutionary origin or instead represent convergent recruitment of similar developmental programs. Full article

Corneal transparency depends on quiescence of stromal cells derived from neural crest cells and a well-controlled extracellular matrix. Disruption of this homeostasis causes fibrotic scarring, a leading cause of blindness. Transforming growth factor-β/Smad3 signaling drives corneal fibrogenesis, but the distinct roles of Smad2 versus Smad3 remain unclear. Smad2 ablation in neural crest cells using Wnt1-Cre mice triggers spontaneous severe corneal opacification along with massive stromal hypercellularity and fibrosis. The fibrotic phenotype occurs in the absence of injury, indicating that Smad2 is essential for balancing Smad3 activity in driving fibrotic signaling. Single-cell RNA sequencing and virtual knockout of Smad2 reveal prominent activation of Smad3-Yes-associated protein (YAP)/TEAD2-transcriptional program in Smad2-null corneas. Biochemical assays confirm that Smad2 loss results in increased Smad3 phosphorylation and formation of nuclear Smad3–YAP–TEAD2 complex. This trimeric complex induces the expression of collagen I, connective tissue growth factor, and cyclin D1. Importantly, pharmacologic inhibition of YAP/TEAD interaction with verteporfin blocks stromal hyperplasia and corneal fibrosis by suppressing the expression of fibrotic and cell cycle genes, which lead to restoration of corneal transparency in Smad2-neural crest-deficient mice. Our findings reveal a unique convergence of YAP/TEAD and TGF-β/Smad3 signaling that can be targeted with verteporfin to prevent corneal scarring and blindness. Full article

Neuroblastoma (NB), the most common extracranial solid tumor of childhood, exemplifies one of the most formidable paradigms of tumor immune evasion (TIME) in pediatric oncology. Despite significant advances in multimodal therapy and the clinical integration of immunotherapeutic strategies, high-risk NB (HR-NB) remains largely refractory to durable immune control. This failure reflects not an absence of immune engagement, but the presence of a highly evolved and developmentally wired immune escape architecture. In this review, we synthesize emerging insights from single-cell, multi-omics, and functional studies to define how developmental lineage, cellular plasticity, metabolic rewiring, epigenetic regulation, and therapy-induced adaptation converge to engineer immune blindness in NB. We discuss how NB’s neural crest origin establishes a baseline of low immunogenicity, which is subsequently reinforced through coordinated suppression of antigen presentation, dominance of immune checkpoint signaling, and profound dysfunction of cytotoxic T and natural killer cells within an immunosuppressive tumor microenvironment. Central to this process is tumor-intrinsic plasticity, whereby lineage instability and dedifferentiation, exacerbated by therapeutic pressure, embed immune silence as a stable tumor state. We highlight evidence positioning RD3 as a master upstream regulator linking cellular identity to immune visibility, governing antigen presentation, innate immune sensing, checkpoint expression, and cytotoxic lymphocyte engagement. Beyond tumor-intrinsic mechanisms, we examine the roles of immunosuppressive myeloid populations, tumor-derived exosomes, metabolic stress, hypoxia, and ferroptosis-associated pathways in reinforcing immune paralysis. Finally, we outline emerging therapeutic strategies aimed at dismantling this architecture, including combinatorial checkpoint blockade, metabolic and epigenetic reprogramming, exosome-targeted interventions, and next-generation immune engineering platforms. Together, this review reframes TIME in NB as a programmable, developmentally rooted process and provides a mechanistic roadmap for restoring immune competence and therapeutic susceptibility in HR disease. Full article

Background/Objectives: Stroke remains the second leading cause of death worldwide, and cell therapy is among the most actively investigated strategies for its treatment. Recent transcriptomic evidence has revealed that 293T cells—the most widely used transient transfection model—possess a neural crest/neuronal lineage, making them a candidate for acute neural tissue engineering. Methods: We implanted iron oxide nanoparticle-labeled 293T cells (293T-ION) into an ischemic rat brain and monitored them longitudinally by 7T MRI, using ION-labeled bone marrow-derived mesenchymal stem cells (rMSC-ION) as a direct comparison. Functional recovery was assessed via mNSS and corner test scores, and infarct size was quantified by MRI. Results: 293T-ION cells showed no migration throughout the 40-day observation period, and functional recovery plateaued early compared with the progressive improvement seen with rMSC-ION. 293T cell implantation provoked pronounced, localized CD68-positive microglial hyperactivation at both implantation and ischemic sites, without migration toward the choroid plexus (CP). In contrast, rMSC-ION actively migrated to the CP and drove superior neuroplasticity marker expression (Ki67, Nestin, NeuN). Conclusions: 293T cells produce transient localized microglial activation and limited brain plasticity, whereas rMSCs drive sustained neurorestoration. Synergistic co-administration of these cell types may represent a future therapeutic strategy bridging hyper-acute and chronic recovery phases. Full article

Neuroblastomas (NBs) are aggressive, therapy-resistant embryonal tumors of neural crest origin, which despite low mutational burdens exhibit high intra-tumoral heterogeneity characterized by adrenergic, noradrenergic, mesenchymal and cancer stem cell (CSC)-like subpopulations. These phenotypes exhibit interconverting plasticity that reflect both stage of transformation during sympathoadrenal development and conditions within the tumor microenvironment. Chemotherapeutic agents promote adrenergic-to-mesenchymal conversion in NBs, which underpins drug resistance, post-therapeutic relapse, metastatic progression, and the plateauing of responses to advances in multimodal therapy. Improved understanding of the molecular mechanisms that regulate NB phenotypic plasticity is essential for identifying novel prognostic markers and potential therapeutic targets. In this article, following introductions into NB, molecular regulation of NB phenotypic plasticity, and the NF-Y transcription factor and its role in development and differentiation, we focus on alternative NF-YAl, NF-YAs and NF-YAx splicing of the NF-Y subunit, NF-YA, and the potential influence that different NF-YA isoforms have on NF-Y function and the NF-Y-transcription factor networks that impact NB cell phenotypes. Particular attention is paid to the novel extra short-form NF-YAx isoform, originally detected as the exclusive NF-YA isoform in a non-MYCN amplified advanced stage 3 NB. This isoform is also induced by doxorubicin in non-Myc amplified SH-SY5Y NB cells and is involved in doxorubicin cytotoxicity. Despite high cytotoxicity, however, NF-YAx selects a resistant subpopulation with mesenchymal/neural crest stem cell-like identity, unveiling a doxorubicin-induced NF-YAx-dependent resistance mechanism, with potential to influence post-therapeutic relapse and disease progression. Therefore, evaluating alternative NF-YA splicing, and especially NF-YAx expression, in advanced stage and post-therapeutic relapsed NBs, may be of both prognostic and therapeutic significance. Full article

The heterogenous mesenchymal stem/stromal cells (MSCs) express the surface antigens associated with distinct cell subpopulations. CD271, characteristic of stem cells derived from the neural crest, could indicate cells with a unique phenotype. The study examined whether the CD271+ subpopulation characterized by better stem and neural properties than the heterogeneous MSC population. The initial Wharton jelly-derived MSCs (WJ-MSCs) population was divided into two subpopulation: CD271-positive (WJ-MSC-CD271+) and CD271-negative (WJ-MSC-CD271−) with Fluorescence-Activated Cell Sorting (FACS). We compared the clonogenic potential and neural marker expression under standard culture conditions and in the presence of nerve tissue components—cerebrospinal fluid (CSF) or nerve tissue fragments (hippocampus). FACS allowed the enrichment of CD271+ cells from 1% to approximately 50%. WJ-MSC-CD271+ is characterized by significantly more self-renewal cells and increased expression of neuronal genes than WJ-MSC-CD271−. Under co-culture with CSF or hippocampal fragments, WJ-MSC-CD271+ contained more cells expressing Β-III-tubulin as well. Finally, we reported that stimulation with epithelial growth factor (EGF) and basal fibroblast growth factor (bFGF) enhanced CD271+ numbers in the initial population and stabilized them in further cell culture. WJ-MSC-CD271+ cells showed improved potential for differentiation into neural progenitors, although further research is needed for their potential use in neurological diseases. Full article

Mesenchymal stem/stromal cells (MSCs) hold promise for treating different equine conditions but enter senescence during culture. Using induced pluripotent stem cells (iPSCs) to derive MSC-like cells (iMSCs) can increase cell availability and diminish the need for invasive and repeated tissue harvesting. While human iMSCs are intensively studied, research on equine iMSCs (eqiMSCs) is very limited and has focused on strategies for spontaneous differentiation to obtain these cells. The aim of this study was to obtain MSC-like cells from equine iPSCs (eqiPSCs) by directing their differentiation via the neural crest pathway. The resulting eqiMSCs downregulated pluripotent gene expression compared to originating eqiPSCs, and the majority of lines met most of the standard criteria for tissue-derived MSCs (immunophenotype and tri-lineage differentiation potential). Nevertheless, eqiMSCs showed some differences from primary equine MSCs, possibly due to their different developmental origin, and displayed certain inter-line variability, which might be related to the different kinetics of independent eqiPSC lines. This study demonstrates for the first time that equine MSC-like cells (eqiMSCs) can be derived from eqiPSCs by directing their differentiation through the neural crest pathway. This constitutes an important advancement towards more sustainable sources of therapeutic cells in veterinary medicine and warrants further exploration of the functional characteristics of these novel cells. Full article

Dental pulp tissue contains mesenchymal stem/progenitor cells that possess high proliferative potential for self-renewal. They are neural-crest derived cells and exhibit multi-lineage differentiation properties. These progenitor stem cells are now recognized as being vital to the dentin regeneration process following injury. Understanding the molecular mechanisms that mediate the differentiation of adult stem cells into odontoblasts and their use in the repair of the dentin–pulp complex is of significant interest in regenerative dental medicine. Dentin Phosphophoryn (DPP), synthesized and processed predominantly by the odontoblasts, functions both as a structural and signaling protein. We had previously demonstrated that DPP activates NF-κB and promotes Wnt5a expression in dental pulp stem cells. In this context, we observed that DPP can activate TAZ, a biologically potent transcriptional coactivator which serves as a downstream element of the NF-κB signaling cascade. Furthermore, binding of NF-κB p65 subunit to the TAZ promoter was facilitated by DPP stimulation, and their interaction was confirmed by ChIP analysis. In addition, DPP-dependent activation of the TAZ/TEAD reporter was confirmed by luciferase activity in DPSCs. Co-immunoprecipitation analysis confirmed the in vivo interaction between TAZ and β-catenin with DPP stimulation. This regulatory complex facilitated TAZ to bind to the conserved TEAD binding motifs of key gene targets involved in odontogenic differentiation such as RUNX2, OSX, OCN, ALP, BMP4, and WNT5A. Some of these genes also contain binding sites for the TCF/LEF transcription factors that interact with the Wnt effector, β-catenin. Activation of TAZ and β-catenin resulted in the upregulation of odontoblast gene expression and reduced expression in the presence of the TAZ–TEAD protein complex inhibitor. Using mandibles of DSPP KO and WT mice, we confirmed reduced TAZ and β-catenin protein levels in the dental pulp cells and in the odontoblasts of DSPP KO mice when compared with WT. Thus, DPP, an extracellular matrix protein, provides biological cues to activate the TAZ signaling pathway that can stimulate the terminal differentiation of DPSCs into functional odontoblasts. Full article

Microtia–atresia is a rare craniofacial malformation primarily affecting the first and second pharyngeal arches, leading to the deformity of the auricle and atresia of the external ear canal. Its etiology is heterogenous and largely unknown, including both genetic and environmental factors. The HOXA4 gene has been identified as potentially pathogenetic for microtia–atresia in three twin families. A hoxa4a mosaic knockdown zebrafish model was constructed using CRISPR/Cas9. hoxa4a was expressed in the mandible during early development in zebrafish, while the F0 mosaic knockdowns exhibited craniofacial malformations with abnormal chondrocyte morphologies. Specifically, hoxa4a knockdown reduced cranial neural crest cell proliferation while increasing apoptosis, markedly downregulating chondrogenic markers sox9a and col2a1a. Consequently, pharyngeal arch chondrocytes exhibited disorganized arrangement and morphological abnormalities, resulting in mandibular hypoplasia. Our findings provide important insights into the role of hoxa4a in zebrafish mandibular development and the pathology of microtia–atresia caused by HOXA4 gene mutations in humans. Full article

Trauma-induced heterotopic ossification (tHO) is characterized by aberrant ectopic bone formation in soft tissue following high-energy trauma, affecting >60% of combat-related amputees and >50% of major burn patients. Current prophylactic strategies (including NSAIDs, bisphosphonates, and low-dose radiation) lack mechanistic specificity, carry significant side effects, and surgical excision carries a 27% recurrence rate. This review reframes tHO pathogenesis through the neural–immune axis, arguing that ectopic bone formation is a downstream consequence of dysregulated neuroimmune signaling rather than a primary osteogenic event. Following trauma, nociceptor activation drives nociception-induced neural inflammation (NINI), releasing substance P (SP) and calcitonin gene-related peptide (CGRP), which disrupts the blood–nerve barrier, mobilizes neural crest-derived progenitor cells, and, alongside BMP-2/SMAD1/5/8 signaling and M1-polarized macrophage activation, establishes a permissive osteogenic microenvironment. A BMP-2/CGRP positive feedback loop sustains aberrant osteogenesis, converging on osteogenic transcription factors Runx2, SOX5/6/9, and Osterix. Dysregulated noncoding RNAs represent promising pre-radiographic biomarkers. This neural–immune framework motivates mechanism-based therapeutic strategies targeting CGRP (fremanezumab, erenumab), SP/NK1 signaling (aprepitant), and macrophage polarization (metformin, palovarotene, rapamycin), with multi-node combination approaches tailored to the temporal stages of tHO offering the most promise for precision prophylaxis. Full article

Tooth development or odontogenesis is a complex morphogenetic process that requires tightly regulated interactions between the oral epithelium and mesenchyme of neural crest origin. In this narrative review, we compile existing knowledge regarding gene regulatory networks and epigenetic factors throughout tooth development from initiation to eruption. Signaling between the epithelium and mesenchyme is mediated by four conserved pathways—Wnt/β-catenin, bone morphogenetic protein (BMP), fibroblast growth factor (FGF), and Sonic hedgehog (Shh)—which operate iteratively and interact through extensive crosstalk at each developmental stage. Transcription factors, such as PAX9, MSX1, PITX2, and LEF1, interpret these signals to control cell fate decisions and differentiation. Epigenetic modifications, including DNA methylation, histone modifications, and microRNA-mediated regulation, provide additional layers of control that fine-tune gene expression programs. Unlike existing reviews that address these regulatory mechanisms separately, here we integrate signaling pathways, transcription factor networks, epigenetic regulation, human genetic disorders, dental stem cell biology, and recent single-cell transcriptomic insights into a unified framework. We discuss opportunities to apply developmental biology knowledge towards regenerative dentistry goals, including iPSC-derived dental models and spatially resolved multi-omics approaches, while acknowledging the considerable gap between preclinical findings and clinical applications. Full article

The type II cadherin Cadherin-19 (CDH19) plays a crucial role in neural crest development. CDH19 regulates cell–cell junctions and migration by forming catenin–cytoskeleton complexes. Although anti-CDH19 monoclonal antibodies (mAbs) are used for specific applications such as Western blotting and immunohistochemistry (IHC), suitable anti-CDH19 mAbs for flow cytometry are limited. Therefore, developing mAbs that specifically recognize cell-surface-expressed CDH19 is essential for advancing both basic research and therapeutic strategies. Here, novel anti-human CDH19 mAbs (Ca₁₉Mabs) were created using flow cytometry-based high-throughput screening. One clone, Ca₁₉Mab-8 (IgG₁, κ), specifically recognized CDH19-overexpressed Chinese hamster ovary-K1 cells but did not bind to other 21 CDHs (including both type I and type II CDHs) in flow cytometry. Additionally, Ca₁₉Mab-8 recognized endogenous CDH19 in the human glioblastoma cell line LN229. The dissociation constant (K_D) of Ca₁₉Mab-8 for LN229/CDH19 was 9.0 × 10⁻⁹ M. Ca₁₉Mab-8 also detected endogenous CDH19 in Western blotting. Furthermore, Ca₁₉Mab-8 can detect CDH19 in IHC using human melanoma tissue. These findings suggest that Ca₁₉Mab-8 is a novel mAb that detects cell-surface-expressed CDH19 with high specificity and is suitable for various applications in basic research. Therefore, Ca₁₉Mab-8 has potential for clinical diagnosis and tumor therapy. Full article