Interplay of SOX and POU factors in regulation of the Nestin gene in neural primordial cells

Xenopus Sox11 Partner Proteins and Functional Domains in Neurogenesis

Sox11, a member of the SoxC family of transcription factors, has distinct functions at different times in neural development. Studies in mouse, frog, chick, and zebrafish show that Sox11 promotes neural fate, neural differentiation, and neuron maturation in the central nervous system. These diverse roles are controlled in part by spatial and temporal-specific protein interactions. However, the partner proteins and Sox11-interaction domains underlying these diverse functions are not well defined. Here, we identify partner proteins and the domains of Xenopus laevis Sox11 required for protein interaction and function during neurogenesis. Our data show that Sox11 co-localizes and interacts with Pou3f2 and Neurog2 in the anterior neural plate and in early neurons, respectively. We also demonstrate that Sox11 does not interact with Neurog1, a high-affinity partner of Sox11 in the mouse cortex, suggesting that Sox11 has species-specific partner proteins. Additionally, we determined that the N-terminus including the HMG domain of Sox11 is necessary for interaction with Pou3f2 and Neurog2, and we established a novel role for the N-terminal 46 amino acids in the specification of placodal progenitors. This is the first identification of partner proteins for Sox11 and of domains required for partner-protein interactions and distinct roles in neurogenesis.

Enhancer Activation by Transcription Factors and Underlying Mechanisms

Enhancers are classified into two classes based on various criteria. Class I enhancers participate primarily in finely tuned cell-specific regulation, as exemplified by the neural enhancers discussed in Chap. 9 . They are activated by simultaneous binding of transcription factors (TFs) to adjacent sites in the core sequence and are marked by moderate levels of H3K27ac modification. Class II enhancers are activated by the reiterated binding of the same TFs at multiple sites and are marked by high levels of H3K27ac modification. Class II enhancers are exemplified by enhancers in the SCR downstream of the Sox2 gene, as also discussed in Chap. 9 . Both classes of enhancers activate transcription similarly with low selectivity toward the promoters.The genomic loci broadly covered by high-level H3K27ac modification were once dubbed "Super-enhancers," implying that they are densely packed enhancers with superpowers in gene regulation. However, marking with H3K27ac modification does not predict the enhancer activity of a sequence; a "Super enhancer" region includes a few ordinary Class II enhancers. Currently, the most reliable criterion for enhancer prediction is cross-species sequence conservation.The mechanism by which transcription factors find and stay on the target enhancer site remains elusive. Results from two approaches, single-molecule live imaging and kinetic analysis using FRAP, are discussed.

Hesperidin ameliorates impairment in hippocampal neural stem cells related to apoptosis induced by methotrexate in adult rats

Neurogenesis is a process of generating neural stem cells (NSCs) as functional neurons can be decreased after chemotherapy treatments. Methotrexate (MTX) is a folate antagonist that is used for cancer treatment but has negative effects, including oxidative stress, neuronal apoptosis and cognitive impairments. Hesperidin (Hsd), a flavonoid found in citrus fruits, has antioxidant and neuroprotection properties. This study investigated whether Hsd could attenuate impairments of hippocampal neural stem cells related to apoptosis induced by MTX. Spraque-Dawley rats (n = 24) were divided into 4 groups: (1) Vehicle group received propylene glycol (21 days) and 0.9% normal saline (day 8 and 15), (2) Hsd group received 100 mg/kg (21 days), (3) MTX group received 75 mg/kg (days 8 and 15) and (4) MTX+Hsd group received MTX, 75 mg/kg (day 8 and 15) and Hsd 100 mg/kg (21 days). Our results showed that MTX decreased hippocampal neural stem cells including SRY (sex determining region Y)-box 2 (SOX2) and nestin. MTX diminished vascular related (VR) Ki-67 positive cells in the hippocampus but not non-vascular related (NVR) Ki-67. Additionally, MTX reduced SOX2, nestin, postsynaptic density protein 95 (PSD-95) and B-cell lymphoma-2 family of proteins (Bcl-2), whereas Bax and caspase-3 were enhanced in the hippocampal tissues. Interestingly, co-treatment with Hsd and MTX revealed upregulation of SOX2, nestin and VR Ki-67 positive cells as well as elevated SOX2, nestin, PSD-95 and Bcl-2 proteins. Moreover, receiving both Hsd and MTX significantly suppressed increased Bax and caspase-3. These results confirm that Hsd can ameliorate MTX-induced impairments of hippocampal NSC proliferation and neuronal apoptosis.

SoxB1 transcription factors are essential for initiating and maintaining the neural plate border gene expression

SoxB1 transcription factors (Sox2/3) are well known for their role in early neural fate specification in the embryo, but little is known about functional roles for SoxB1 factors in non-neural ectodermal cell types, such as the neural plate border (NPB). Using Xenopus laevis , we set out to determine if SoxB1 transcription factors have a regulatory function in NPB formation. Herein, we show that SoxB1 factors are necessary for NPB formation, and that prolonged SoxB1 factor activity blocks the transition from a NPB to a neural crest state. Using ChIP-seq we demonstrate that Sox3 is enriched upstream of NPB genes in early NPB cells and, surprisingly, in blastula stem cells. Depletion of SoxB1 factors in blastula stem cells results in downregulation of NPB genes. Finally, we identify Pou5f3 factors as a potential SoxB1 partners in regulating the formation of the NPB and show their combined activity is needed to maintain NPB gene expression. Together, these data identify a novel role for SoxB1 factors in the establishment and maintenance of the NPB, in part through partnership with Pou5f3 factors.

SoxC transcription factors shape the epigenetic landscape to establish competence for sensory differentiation in the mammalian organ of Corti

The auditory organ of Corti is comprised of only two major cell types-the mechanosensory hair cells and their associated supporting cells-both specified from a single pool of prosensory progenitors in the cochlear duct. Here, we show that competence to respond to Atoh1, a transcriptional master regulator necessary and sufficient for induction of mechanosensory hair cells, is established in the prosensory progenitors between E12.0 and 13.5. The transition to the competent state is rapid and is associated with extensive remodeling of the epigenetic landscape controlled by the SoxC group of transcription factors. Conditional loss of Sox4 and Sox11-the two homologous family members transiently expressed in the inner ear at the time of competence establishment-blocks the ability of prosensory progenitors to differentiate as hair cells. Mechanistically, we show that Sox4 binds to and establishes accessibility of early sensory lineage-specific regulatory elements, including ones associated with Atoh1 and its direct downstream targets. Consistent with these observations, overexpression of Sox4 or Sox11 prior to developmental establishment of competence precociously induces hair cell differentiation in the cochlear progenitors. Further, reintroducing Sox4 or Sox11 expression restores the ability of postnatal supporting cells to differentiate as hair cells in vitro and in vivo. Our findings demonstrate the pivotal role of SoxC family members as agents of epigenetic and transcriptional changes necessary for establishing competence for sensory receptor differentiation in the inner ear.

Arsenic Impairs Differentiation of Human Induced Pluripotent Stem Cells into Cholinergic Motor Neurons

Arsenic exposure during embryogenesis can lead to improper neurodevelopment and changes in locomotor activity. Additionally, in vitro studies have shown that arsenic inhibits the differentiation of sensory neurons and skeletal muscle. In the current study, human-induced pluripotent stem (iPS) cells were differentiated into motor neurons over 28 days, while being exposed to up to 0.5 μM arsenic. On day 6, neuroepithelial progenitor cells (NEPs) exposed to arsenic had reduced transcript levels of the neural progenitor/stem cell marker nestin (NES) and neuroepithelial progenitor marker SOX1, while levels of these transcripts were increased in motor neuron progenitors (MNPs) at day 12. In day 18 early motor neurons (MNs), choline acetyltransferase (CHAT) expression was reduced two-fold in cells exposed to 0.5 μM arsenic. RNA sequencing demonstrated that the cholinergic synapse pathway was impaired following exposure to 0.5 μM arsenic, and that transcript levels of genes involved in acetylcholine synthesis (CHAT), transport (solute carriers, SLC18A3 and SLC5A7) and degradation (acetylcholinesterase, ACHE) were all downregulated in day 18 early MNs. In day 28 mature motor neurons, arsenic significantly downregulated protein expression of microtubule-associated protein 2 (MAP2) and ChAT by 2.8- and 2.1-fold, respectively, concomitantly with a reduction in neurite length. These results show that exposure to environmentally relevant arsenic concentrations dysregulates the differentiation of human iPS cells into motor neurons and impairs the cholinergic synapse pathway, suggesting that exposure impairs cholinergic function in motor neurons.

Craniofacial Development Is Fine-Tuned by Sox2

The precise control of neural crest stem cell delamination, migration and differentiation ensures proper craniofacial and head development. Sox2 shapes the ontogeny of the cranial neural crest to ensure precision of the cell flow in the developing head. Here, we review how Sox2 orchestrates signals that control these complex developmental processes.

A Bone Morphogenetic Protein Signaling Inhibitor, LDN193189, Converts Ischemia-Induced Multipotent Stem Cells into Neural Stem/Progenitor Cell-Like Cells

Stem cell therapy is used to restore neurological function in stroke patients. We have previously reported that ischemia-induced multipotent stem cells (iSCs), which are likely derived from brain pericytes, develop in poststroke human and mouse brains. Although we have demonstrated that iSCs can differentiate into neural lineage cells, the factors responsible for inducing this differentiation remain unclear. In this study, we found that LDN193189, a bone morphogenetic protein (BMP) inhibitor, caused irreversible changes in the shape of iSCs. In addition, compared with iSCs incubated without LDN193189, the iSCs incubated with LDN193189 (LDN-iSCs) showed upregulated expression of neural lineage-related genes and proteins, including those expressed in neural stem/progenitor cells (NSPCs), and downregulated expression of mesenchymal and pericytic-related genes and proteins. Moreover, microarray analysis revealed that LDN-iSCs and NSPCs had similar gene expression profiles. Furthermore, LDN-iSCs differentiated into electrophysiologically functional neurons. These results indicate that LDN193189 induces NSPC-like cells from iSCs, suggesting that bioactive molecules regulating BMP signaling are potential targets for promoting neurogenesis from iSCs in the pathological brain, such as during ischemic stroke. We believe that our findings will bring us one step closer to the clinical application of iSCs.

Characterization of the transcription factor Sox3 regulating the gonadal development of pearlscale angelfish (Centropyge vrolikii)

As a member of the Sox gene family, Sox3 plays a vital role in gonadal development and gametogenesis. Nevertheless, the exact expression pattern of this gene in fish is still unknown. Here, we identified the Sox3 gene of Centropyge vrolikii, namely, Cv-Sox3. The Cv-Sox3 mRNA expression in the ovary and testis was detected by reverse transcription-polymerase chain reaction (RT-PCR) analysis, and the mRNA expression level of Cv-Sox3 in the ovary in the resting stage was significantly higher than that in other tissues. The phylogenetic tree and alignment of multiple sequences were constructed to analyze the evolutionary relationships of Cv-Sox3. Cv-Sox3 was relatively conserved in the evolution of teleost fish, indicating the importance and similarity of its function. The in situ hybridization results demonstrate that Cv-Sox3 was present in the follicle cells and cytoplasm of oocytes in the ovary of different stages, and the positive signals occurred in germ cells of the testis. After interfering with Cv-Sox3, the growth rate of ovarian cells in culture became slow, and the expression of ovary-bias-related genes Cyp19a and Foxl2 significantly increased. Meanwhile, the expression of testis-bias-related genes Dmrt1, Sox9, Cyp11a, Amh, and Sox8 significantly decreased. These results suggest that Cv-Sox3 gene might be expressed in the germ cells of male and female gonads during gonadal development. This study provides a precise expression pattern of Cv-Sox3 and demonstrates that Cv-Sox3 might play a significant role in the reproductive regulation of C. vrolikii. In this study, Sox3 of C. vrolikii (Cv-Sox3) was cloned to understand the expression pattern in the gonadal development, which is expressed in germ cells, involved in the process of gonadal development. The results demonstrated that Cv-Sox3 may play a significant role in the reproductive regulation of C. vrolikii.

RNA-binding protein signaling in adult neurogenesis

The process of neurogenesis in the brain, including cell proliferation, differentiation, survival, and maturation, results in the formation of new functional neurons. During embryonic development, neurogenesis is crucial to produce neurons to establish the nervous system, but the process persists in certain brain regions during adulthood. In adult neurogenesis, the production of new neurons in the hippocampus is accomplished via the division of neural stem cells. Neurogenesis is regulated by multiple factors, including gene expression at a temporal scale and post-transcriptional modifications. RNA-binding Proteins (RBPs) are known as proteins that bind to either double- or single-stranded RNA in cells and form ribonucleoprotein complexes. The involvement of RBPs in neurogenesis is crucial for modulating gene expression changes and posttranscriptional processes. Since neurogenesis affects learning and memory, RBPs are closely associated with cognitive functions and emotions. However, the pathways of each RBP in adult neurogenesis remain elusive and not clear. In this review, we specifically summarize the involvement of several RBPs in adult neurogenesis, including CPEB3, FXR2, FMRP, HuR, HuD, Lin28, Msi1, Sam68, Stau1, Smaug2, and SOX2. To understand the role of these RBPs in neurogenesis, including cell proliferation, differentiation, survival, and maturation as well as posttranscriptional gene expression, we discussed the protein family, structure, expression, functional domain, and region of action. Therefore, this narrative review aims to provide a comprehensive overview of the RBPs, their function, and their role in the process of adult neurogenesis as well as to identify possible research directions on RBPs and neurogenesis.

Melatonin Ameliorates Valproic Acid-Induced Neurogenesis Impairment: The Role of Oxidative Stress in Adult Rats

Background

Valproic acid (anticonvulsant medication) has been found to inhibit histone deacetylase activity and suppress hippocampal neurogenesis, which causes memory impairment in both humans and rodents. The neurohormone melatonin, which regulates mammalian seasonal and circadian physiology, has recently been shown to have neuroprotective properties, counteracting memory impairment associated with VPA-caused hippocampal neurogenesis reduction. This study is aimed at investigating the molecular mechanisms of melatonin associated with VPA-induced hippocampal neurogenesis and memory impairment.

Methods

Male Spraque-Dawley rats received VPA (300 mg/kg) twice daily or melatonin (8 mg/kg/day) or some rats were given melatonin for 14 days during VPA administration.

Results

The VPA-treated rats showed a significant increase in malondialdehyde (MDA) levels in the hippocampus and p21-positive cells in the subgranular zone (SGZ) of the dentate gyrus (DG) but decreased superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activities. Moreover, VPA significantly decreased levels of nestin, Notchl, nuclear factor erythroid 2-related factor 2 (Nrf2), doublecortin (DCX), sex determining region Y-box 2 (SOX2), and brain-derived neurotrophic factor (BDNF).

Conclusions

We found that melatonin was able to counteract these neurotoxic effects, acting as a neuroprotectant in VPA-induced memory hippocampal neurogenesis impairment by preventing intracellular oxidative stress and increasing antioxidant activity.

The Nestin neural enhancer is essential for normal levels of endogenous Nestin in neuroprogenitors but is not required for embryo development

Enhancers are vitally important during embryonic development to control the spatial and temporal expression of genes. Recently, large scale genome projects have identified a vast number of putative developmental regulatory elements. However, the proportion of these that have been functionally assessed is relatively low. While enhancers have traditionally been studied using reporter assays, this approach does not characterise their contribution to endogenous gene expression. We have studied the murine Nestin (Nes) intron 2 enhancer, which is widely used to direct exogenous gene expression within neural progenitor cells in cultured cells and in vivo. We generated CRISPR deletions of the enhancer region in mice and assessed their impact on Nes expression during embryonic development. Loss of the Nes neural enhancer significantly reduced Nes expression in the developing CNS by as much as 82%. By assessing NES protein localization, we also show that this enhancer region contains repressor element(s) that inhibit Nes expression within the vasculature. Previous reports have stated that Nes is an essential gene, and its loss causes embryonic lethality. We also generated 2 independent Nes null lines and show that both develop without any obvious phenotypic effects. Finally, through crossing of null and enhancer deletion mice we provide evidence of trans-chromosomal interaction of the Nes enhancer and promoter.

Circ_0039411 promotes papillary thyroid carcinoma development through mediating the miR-423-5p/SOX4 signaling

BACKGROUND

Papillary thyroid carcinoma is the most frequent histological subtype of thyroid cancer with a high incidence. We aimed to explore the function of circular RNA_0039411 (circ_0039411) and its associated mechanism in papillary thyroid carcinoma progression.

METHODS

Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were conducted to determine the expression of RNA and protein, respectively. The colony formation ability, migration, invasion, and apoptosis were analyzed by colony formation assay, transwell migration assay, transwell invasion assay, and flow cytometry. Cell glycolytic metabolism was analyzed using fluorescence-based glucose assay kit and fluorescence-based lactate assay kit. Dual-luciferase reporter assay and RNA-Pull-Down Assay were performed to validate the binding between microRNA-423-5p (miR-423-5p) and circ_0039411 or SRY-box transcription factor 4 (SOX4). The xenograft tumor model was used to assess the role of circ_0039411 in the tumor growth in vivo.

RESULTS

Circ_0039411 was highly expressed in papillary thyroid carcinoma tissues and cell lines compared with adjacent normal tissues and NTHY-ORI3.1 cells. Circ_0039411 interference suppressed the colony formation ability, migration, invasion, and glycolysis but promoted the apoptosis of papillary thyroid carcinoma cells. MiR-423-5p was a target of circ_0039411 in papillary thyroid carcinoma cells. Circ_0039411 knockdown-mediated effects in papillary thyroid carcinoma cells were largely overturned by the silence of miR-423-5p. MiR-423-5p bound to the 3' untranslated region (3'UTR) of SOX4. SOX4 overexpression largely reversed circ_0039411 silencing-mediated effects in papillary thyroid carcinoma cells. Circ_0039411 positively regulated SOX4 expression by sponging miR-423-5p in papillary thyroid carcinoma cells. Circ_0039411 silencing notably suppressed the growth of xenograft tumors in vivo.

CONCLUSION

Circ_0039411 promoted the malignant behaviors of papillary thyroid carcinoma cells partly depending on the regulation of the miR-423-5p/SOX4 axis.

Temporal proteomics during neurogenesis reveals large-scale proteome and organelle remodeling via selective autophagy

Cell state changes are associated with proteome remodeling to serve newly emergent cell functions. Here, we show that NGN2-driven conversion of human embryonic stem cells to induced neurons (iNeurons) is associated with increased PINK1-independent mitophagic flux that is temporally correlated with metabolic reprogramming to support oxidative phosphorylation. Global multiplex proteomics during neurogenesis revealed large-scale remodeling of functional modules linked with pluripotency, mitochondrial metabolism, and proteostasis. Differentiation-dependent mitophagic flux required BNIP3L and its LC3-interacting region (LIR) motif, and BNIP3L also promoted mitophagy in dopaminergic neurons. Proteomic analysis of ATG12^-/- iNeurons revealed accumulation of endoplasmic reticulum, Golgi, and mitochondria during differentiation, indicative of widespread organelle remodeling during neurogenesis. This work reveals broad organelle remodeling of membrane-bound organelles during NGN2-driven neurogenesis via autophagy, identifies BNIP3L's central role in programmed mitophagic flux, and provides a proteomic resource for elucidating how organelle remodeling and autophagy alter the proteome during changes in cell state.

Hierarchical reactivation of transcription during mitosis-to-G1 transition by Brn2 and Ascl1 in neural stem cells

During mitosis, chromatin condensation is accompanied by a global arrest of transcription. Recent studies suggest transcriptional reactivation upon mitotic exit occurs in temporally coordinated waves, but the underlying regulatory principles have yet to be elucidated. In particular, the contribution of sequence-specific transcription factors (TFs) remains poorly understood. Here we report that Brn2, an important regulator of neural stem cell identity, associates with condensed chromatin throughout cell division, as assessed by live-cell imaging of proliferating neural stem cells. In contrast, the neuronal fate determinant Ascl1 dissociates from mitotic chromosomes. ChIP-seq analysis reveals that Brn2 mitotic chromosome binding does not result in sequence-specific interactions prior to mitotic exit, relying mostly on electrostatic forces. Nevertheless, surveying active transcription using single-molecule RNA-FISH against immature transcripts reveals differential reactivation kinetics for key targets of Brn2 and Ascl1, with transcription onset detected in early (anaphase) versus late (early G1) phases, respectively. Moreover, by using a mitotic-specific dominant-negative approach, we show that competing with Brn2 binding during mitotic exit reduces the transcription of its target gene Nestin Our study shows an important role for differential binding of TFs to mitotic chromosomes, governed by their electrostatic properties, in defining the temporal order of transcriptional reactivation during mitosis-to-G1 transition.

Sorting Sox: Diverse Roles for Sox Transcription Factors During Neural Crest and Craniofacial Development

Sox transcription factors play many diverse roles during development, including regulating stem cell states, directing differentiation, and influencing the local chromatin landscape. Of the twenty vertebrate Sox factors, several play critical roles in the development the neural crest, a key vertebrate innovation, and the subsequent formation of neural crest-derived structures, including the craniofacial complex. Herein, we review the specific roles for individual Sox factors during neural crest cell formation and discuss how some factors may have been essential for the evolution of the neural crest. Additionally, we describe how Sox factors direct neural crest cell differentiation into diverse lineages such as melanocytes, glia, and cartilage and detail their involvement in the development of specific craniofacial structures. Finally, we highlight several SOXopathies associated with craniofacial phenotypes.

In Silico Identification of SOX1 Post-Translational Modifications Highlights a Shared Protein Motif

The transcription factor SOX1 is a key regulator of neural stem cell development, acting to keep neural stem cells (NSCs) in an undifferentiated state. Postnatal expression of Sox1 is typically confined to the central nervous system (CNS), however, its expression in non-neural tissues has recently been implicated in tumorigenesis. The mechanism through which SOX1 may exert its function is not fully understood, and studies have mainly focused on changes in SOX1 expression at a transcriptional level, while its post-translational regulation remains undetermined. To investigate this, data were extracted from different publicly available databases and analysed to search for putative SOX1 post-translational modifications (PTMs). Results were compared to PTMs associated with SOX2 in order to identify potentially key PTM motifs common to these SOXB1 proteins, and mapped on SOX1 domain structural models. This approach identified several putative acetylation, phosphorylation, glycosylation and sumoylation sites within known functional domains of SOX1. In particular, a novel SOXB1 motif (xKSExSxxP) was identified within the SOX1 protein, which was also found in other unrelated proteins, most of which were transcription factors. These results also highlighted potential phospho-sumoyl switches within this SOXB1 motif identified in SOX1, which could regulate its transcriptional activity. This analysis indicates different types of PTMs within SOX1, which may influence its regulatory role as a transcription factor, by bringing changes to its DNA binding capacities and its interactions with partner proteins. These results provide new research avenues for future investigations on the mechanisms regulating SOX1 activity, which could inform its roles in the contexts of neural stem cell development and cancer.

Genome-wide DNA-binding profile of SRY-box transcription factor 3 (SOX3) in mouse testes

Spermatogenesis is the male version of gametogenesis, where germ cells are transformed into haploid spermatozoa through a tightly controlled series of mitosis, meiosis and differentiation. This process is reliant on precisely timed changes in gene expression controlled by several different hormonal and transcriptional mechanisms. One important transcription factor is SRY-box transcription factor 3 (SOX3), which is transiently expressed within the uncommitted spermatogonial stem cell population. Sox3-null mouse testes exhibit a block in spermatogenesis, leading to infertility or subfertility. However, the molecular role of SOX3 during spermatogonial differentiation remains poorly understood because the genomic regions targeted by this transcription factor have not been identified. In this study we used chromatin immunoprecipitation sequencing to identify and characterise the endogenous genome-wide binding profile of SOX3 in mouse testes at Postnatal Day 7. We show that neurogenin3 (Neurog3 or Ngn3) is directly targeted by SOX3 in spermatogonial stem cells via a novel testes-specific binding site. We also implicate SOX3, for the first time, in direct regulation of histone gene expression and demonstrate that this function is shared by both neural progenitors and testes, and with another important transcription factor required for spermatogenesis, namely promyelocytic leukaemia zinc-finger (PLZF). Together, these data provide new insights into the function of SOX3 in different stem cell contexts.

Sox17 Controls Emergence and Remodeling of Nestin-Expressing Coronary Vessels

RATIONALE

The molecular mechanisms underlying the formation of coronary arteries during development and during cardiac neovascularization after injury are poorly understood. However, a detailed description of the relevant signaling pathways and functional TFs (transcription factors) regulating these processes is still incomplete.

OBJECTIVE

The goal of this study is to identify novel cardiac transcriptional mechanisms of coronary angiogenesis and vessel remodeling by defining the molecular signatures of coronary vascular endothelial cells during these complex processes.

METHODS AND RESULTS

We demonstrate that Nes-gfp and Nes-CreERT2 transgenic mouse lines are novel tools for studying the emergence of coronary endothelium and targeting sprouting coronary vessels (but not ventricular endocardium) during development. Furthermore, we identify Sox17 as a critical TF upregulated during the sprouting and remodeling of coronary vessels, visualized by a specific neural enhancer from the Nestin gene that is strongly induced in developing arterioles. Functionally, genetic-inducible endothelial deletion of Sox17 causes deficient cardiac remodeling of coronary vessels, resulting in improper coronary artery formation.

CONCLUSIONS

We demonstrated that Sox17 TF regulates the transcriptional activation of Nestin's enhancer in developing coronary vessels while its genetic deletion leads to inadequate coronary artery formation. These findings identify Sox17 as a critical regulator for the remodeling of coronary vessels in the developing heart.

SOX11-induced decrease in vimentin and an increase in prostate cancer cell migration attributed to cofilin activity

SOX11 is a transcription factor in the SOX family of genes that regulate multiple cellular events by influencing the expression of key genes in developmental, physiological, and tumorigenic cells. To elucidate the role of SOX11 in prostate cancer cells, PC-3 prostate cancer cells were cloned (S6 and S9 cells) to highly express SOX11. We demonstrated that both S6 and S9 lose vimentin expression, acquiring epithelial marker proteins, which indicates the Epithelial state phenotype. S6 and S9 cells have cancer-promoting characteristics that include higher migratory properties compared with control cells. The mechanisms that are responsible for the enhanced migration are cofilin activity and keratin 18 expression. TCGA (The Cancer Genome Atlas) dataset analysis revealed that metastatic prostate cancer tumors tend to have more SOX11 gene amplification compared with primary tumors. These results suggest the tumor promotive role and epithelial protein induction of SOX11 in prostate cancer cell.

Sox genes in Agasicles hygrophila (Coleoptera: Chrysomelidae) are involved in ovarian development and oogenesis

The alligator weed flea beetle, Agasicles hygrophila is a monophagous natural enemy of the invasive alligator weed Alternanthera philoxeroides. Oogenesis plays a vital role in the process of individual development and population continuation of oviparous insects. Sox is an ancient and ubiquitous metazoan gene family that plays a key regulatory role in various physiological processes, including oogenesis, which is closely related to fecundity. In this study, two Sox genes AhDichaete and AhSox3 were cloned and characterized, and then the expression profiles of AhDichaete and AhSox3 were qualified by a quantitative reverse transcription-polymerase chain reaction. The result showed that these two Sox genes were expressed significantly higher in ovary, especially in the adult developmental stage. Furthermore, the functions of AhDichaete and AhSox3 in A. hygrophila females were studied using RNA interference (RNAi). Fewer offsprings were produced when AhDichaete and AhSox3 RNAi females mated with wild-type males. Moreover, dsAhSox3 injection reduced the hatching rate of eggs but injection with dsAhDichaete did not. Further study of the reproductive system of AhDichaete and AhSox3 RNAi females showed that yolk protein deposition reduction in the ovarioles, then the expression of vitellogenin gene AhVg2 in ovaries was decreased. These results indicate that AhDichaete and AhSox3 play an important regulatory role in the process of ovarian development and oogenesis by affecting yolk synthesis in the ovary of A. hygrophila.

Adult and endemic neurogenesis in the vestibular nuclei after unilateral vestibular neurectomy

We previously revealed adult reactive neurogenesis in deafferented vestibular nuclei following unilateral vestibular neurectomy (UVN) in the feline model. We recently replicated the same surgery in a rodent model and aimed to elucidate the origin and fate of newly generated cells following UVN. We used specific markers of cell proliferation, glial reaction, and cell differentiation in the medial vestibular nucleus (MVN) of adult rats. UVN induced an intense cell proliferation and glial reaction with an increase of GFAP-Immunoreactive (Ir), IBA1-Ir and Olig2-Ir cells 3 days after the lesion in the deafferented MVN. Most of the newly generated cells survived after UVN and differentiated into oligodendrocytes, astrocytes, microglial cells and GABAergic neurons. Interestingly, UVN induced a significant increase in a population of cells colocalizing SOX2 and GFAP 3 days after lesion in the deafferented MVN indicating the probable presence of multipotent cells in the vestibular nuclei. The concomitant increase in BrdU- and SOX2-Ir cells with the presence of SOX2 and GFAP colocalization 3 days after UVN in the deafferented MVN may support local mitotic activity of endemic quiescent neural stem cells in the parenchyma of vestibular nuclei.

Astrocyte-Specific Deletion of Sox2 Promotes Functional Recovery After Traumatic Brain Injury

Injury to the adult brain induces activation of local astrocytes, which serves as a compensatory response that modulates tissue damage and recovery. However, the mechanism governing astrocyte activation during brain injury remains largely unknown. Here we provide in vivo evidence that SOX2, a transcription factor critical for stem cells and brain development, is also required for injury-induced activation of adult cortical astrocytes. Genome-wide chromatin immunoprecipitation-seq analysis of mouse cortical tissues reveals that SOX2 binds to regulatory regions of genes associated with signaling pathways that control glial cell activation, such as Nr2e1, Mmd2, Wnt7a, and Akt2. Astrocyte-specific deletion of Sox2 in adult mice greatly diminishes glial response to controlled cortical impact injury and, most unexpectedly, dampens injury-induced cortical loss and benefits behavioral recovery of mice after injury. Together, these results uncover an essential role of SOX2 in somatic cells under pathological conditions and indicate that SOX2-dependent astrocyte activation could be targeted for functional recovery after traumatic brain injury.

Sox2 gene regulation via the D1 enhancer in embryonic neural tube and neural crest by the combined action of SOX2 and ZIC2

The transcription factor (TF) SOX2 regulates various stem cells and tissue progenitors via functional interactions with cell type-specific partner TFs that co-bind to enhancer sequences. Neural progenitors are the major embryonic tissues where SOX2 assumes central regulatory roles. In order to characterize the partner TFs of SOX2 in neural progenitors, we investigated the regulation of the D1 enhancer of the Sox2 gene, which is activated in the embryonic neural tube (NT) and neural crest (NC), using chicken embryo electroporation. We identified essential TF binding sites for a SOX, and two ZIC TFs in the activation of the D1 enhancer. By comparison of dorso-ventral and antero-posterior patterns of D1 enhancer activation, and the effect of mutations on the enhancer activation patterns with TF expression patterns, we determined SOX2 and ZIC2 as the major D1 enhancer-activating TFs. Binding of these TFs to the D1 enhancer sequence was confirmed by chromatin immunoprecipitation analysis. The combination of SOX2 and ZIC2 TFs activated the enhancer in both the NT and NC. These results indicate that SOX2 and ZIC2, which have been known to play major regulatory roles in neural progenitors, do functionally cooperate. In addition, the recently demonstrated SOX2 expression during the NC development is accounted for at least partly by the D1 enhancer activity. Deletion of the D1 enhancer sequence from the mouse genome, however, did not affect the mouse development, indicating functional redundancies of other enhancers.

SOX2 for Stem Cell Therapy and Medical Use: Pros or Cons?

Stem cell transplantation is a fast-developing technique, which includes stem cell isolation, purification, and storage, and it is in high demand in the industry. In addition, advanced applications of stem cell transplantation, including differentiation, gene delivery, and reprogramming, are presently being studied in clinical trials. In contrast to somatic cells, stem cells are self-renewing and have the ability to differentiate; however, the molecular mechanisms remain unclear. SOX2 (sex-determining region Y [SRY]-box 2) is one of the well-known reprogramming factors, and it has been recognized as an oncogene associated with cancer induction. The exclusion of SOX2 in reprogramming methodologies has been used as an alternative cancer treatment approach. However, the manner by which SOX2 induces oncogenic effects remains unclear, with most studies demonstrating its regulation of the cell cycle and no insight into the maintenance of cellular stemness. For controlling certain critical pathways, including Shh and Wnt pathways, SOX2 is considered irreplaceable and is required for the normal functioning of stem cells, particularly neural stem cells. In this report, we discussed the functions of SOX2 in both stem and cancer cells, as well as how this powerful regulator can be used to control cell fate.

Epigenomic Profiling Discovers Trans-lineage SOX2 Partnerships Driving Tumor Heterogeneity in Lung Squamous Cell Carcinoma

Molecular characterization of lung squamous cell carcinoma (LUSC), one of the major subtypes of lung cancer, has not sufficiently improved its nonstratified treatment strategies over decades. Accumulating evidence suggests that lineage-specific transcriptional regulators control differentiation states during cancer evolution and underlie their distinct biological behaviors. In this study, by investigating the super-enhancer landscape of LUSC, we identified a previously undescribed "neural" subtype defined by Sox2 and a neural lineage factor Brn2, as well as the classical LUSC subtype defined by Sox2 and its classical squamous partner p63. Robust protein-protein interaction and genomic cooccupancy of Sox2 and Brn2, in place for p63 in the classical LUSC, indicated their transcriptional cooperation imparting this unique lineage state in the "neural" LUSC. Forced expression of p63 downregulated Brn2 in the "neural" LUSC cells and invoked the classical LUSC lineage with more squamous/epithelial features, which were accompanied by increased activities of ErbB/Akt and MAPK-ERK pathways, suggesting differential dependency. Collectively, our data demonstrate heterogeneous cell lineage states of LUSC featured by Sox2 cooperation with Brn2 or p63, for which distinct therapeutic approaches may be warranted. SIGNIFICANCE: Epigenomic profiling reveals a novel subtype of lung squamous cell carcinoma with neural differentiation.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/24/6084/F1.large.jpg.

SOX4 regulates invasion of bladder cancer cells via repression of WNT5a

Sry-Related HMG-BOX-4 (SOX4) is a developmental transcription factor that is overexpressed in as many as 23% of bladder cancer patients; however, the role of SOX4 in bladder cancer tumorigenesis is not yet well understood. Given the many roles of SOX4 in embryonic development and the context-dependent regulation of gene expression, in this study, we sought to determine the role of SOX4 in bladder cancer and to identify SOX4-regulated genes that may contribute to tumorigenesis. For this purpose, we employed a CRISPR interference (CRISPRi) method to transcriptionally repress SOX4 expression in T24 bladder cancer cell lines, 'rescued' these cell lines with the lentiviral-mediated expression of SOX4, and performed whole genome expression profiling. The cells in which SOX4 was knocked down (T24-SOX4-KD) exhibited decreased invasive capabilities, but no changes in migration or proliferation, whereas rescue experiments with SOX4 lentiviral vector restored the invasive phenotype. Gene expression profiling revealed 173 high confidence SOX4-regulated genes, including WNT5a as a potential target of repression by SOX4. Treatment of the T24-SOX4-KD cells with a WNT5a antagonist restored the invasive phenotype observed in the T24-scramble control cells and the SOX4 lentiviral-rescued cells. High WNT5a expression was associated with a decreased invasion and WNT5a expression inversely correlated with SOX4 expression, suggesting that SOX4 can negatively regulate WNT5a levels either directly or indirectly and that WNT5a likely plays a protective role against invasion in bladder cancer cells.

OCT4 and PAX6 determine the dual function of SOX2 in human ESCs as a key pluripotent or neural factor

Background

Sox2 is a well-established pluripotent transcription factor that plays an essential role in establishing and maintaining pluripotent stem cells (PSCs). It is also thought to be a linage specifier that governs PSC neural lineage specification upon their exiting the pluripotent state. However, the exact role of SOX2 in human PSCs was still not fully understood. In this study, we studied the role of SOX2 in human embryonic stem cells (hESCs) by gain- and loss-of-function approaches and explored the possible underlying mechanisms.

Results

We demonstrate that knockdown of SOX2 induced hESC differentiation to endoderm-like cells, whereas overexpression of SOX2 in hESCs enhanced their pluripotency under self-renewing culture conditions but promoted their neural differentiation upon replacing the culture to non-self-renewal conditions. We show that this culture-dependent dual function of SOX2 was probably attributed to its interaction with different transcription factors predisposed by the culture environments. Whilst SOX2 interacts with OCT4 under self-renewal conditions, we found that, upon neural differentiation, PAX6, a key neural transcription factor, is upregulated and shows interaction with SOX2. The SOX2-PAX6 complex has different gene regulation pattern from that of SOX2-OCT4 complex.

Conclusions

Our work provides direct evidence that SOX2 is necessarily required for hESC pluripotency; however, it can also function as a neural factor, depending on the environmental input. OCT4 and PAX6 might function as key SOX2-interacting partners that determine the function of SOX2 in hESCs.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1228-7) contains supplementary material, which is available to authorized users.

The long noncoding RNA ST7-AS1 promotes laryngeal squamous cell carcinoma by stabilizing CARM1

The laryngeal squamous cell carcinoma (LSCC) represents a malignant cancer and contributes largely to head and neck tumorigenesis. The molecular mechanisms for LSCC progression are poorly understood. In current work, we identified long non-coding RNA (lncRNA) termed suppressor of tumorigenicity 7 antisense RNA 1 (ST7-AS1) as an oncogenic factor in LSCC. ST7-AS1 is frequently overexpressed in LSCC tissues and cell lines. ST7-AS1 is required for the malignancy of LSCC cells through migration, tumor sphere formation assay and in vivo implantation. Mechanistically, ST7-AS1 could interact with CARM1, a well characterized protein arginine methyltransferase and protect CARM1 from ubiquitin-dependent degradation. CARM1 can methylate Sox-2, a pluripotent transcription factor. Thus, ST7-AS1 might mediate its oncogenic effect by signaling through CARM1-Sox-2 axis to enhance Sox-2 self-association and transactivation activity. Collectively, we have unraveled a ST7-AS1/CARM1/Sox-2 signaling axis in LSCC and may have created novel interconnections between noncoding RNAs and cancer development.

Duplication and expression of Sox genes in spiders

BACKGROUND

The Sox family of transcription factors is an important part of the genetic 'toolbox' of all metazoans examined to date and is known to play important developmental roles in vertebrates and insects. However, outside the commonly studied Drosophila model little is known about the repertoire of Sox family transcription factors in other arthropod species. Here we characterise the Sox family in two chelicerate species, the spiders Parasteatoda tepidariorum and Stegodyphus mimosarum, which have experienced a whole genome duplication (WGD) in their evolutionary history.

RESULTS

We find that virtually all of the duplicate Sox genes have been retained in these spiders after the WGD. Analysis of the expression of Sox genes in P. tepidariorum embryos suggests that it is likely that some of these genes have neofunctionalised after duplication. Our expression analysis also strengthens the view that an orthologue of vertebrate Group B1 genes, SoxNeuro, is implicated in the earliest events of CNS specification in both vertebrates and invertebrates. In addition, a gene in the Dichaete/Sox21b class is dynamically expressed in the spider segment addition zone, suggestive of an ancient regulatory mechanism controlling arthropod segmentation as recently suggested for flies and beetles. Together with the recent analysis of Sox gene expression in the embryos of other arthropods, our findings support the idea of conserved functions for some of these genes, including a potential role for SoxC and SoxD genes in CNS development and SoxF in limb development.

CONCLUSIONS

Our study provides a new chelicerate perspective to understanding the evolution and function of Sox genes and how the retention of duplicates of such important tool-box genes after WGD has contributed to different aspects of spider embryogenesis. Future characterisation of the function of these genes in spiders will help us to better understand the evolution of the regulation of important developmental processes in arthropods and other metazoans including neurogenesis and segmentation.

Direct Reprogramming of Glioblastoma Cells into Neurons Using Small Molecules

Glioblastoma multiforme, a type of deadly brain cancer, originates most commonly from astrocytes found in the brain. Current multimodal treatments for glioblastoma minimally increase life expectancy, but significant advancements in prognosis have not been made in the past few decades. Here we investigate cellular reprogramming for inhibiting the aggressive proliferation of glioblastoma cells. Cellular reprogramming converts one differentiated cell type into another type based on the principles of regenerative medicine. In this study, we used cellular reprogramming to investigate whether small molecule mediated reprogramming could convert glioblastoma cells into neurons. We investigated a novel method for reprogramming U87MG human glioblastoma cells into terminally differentiated neurons using a small molecule cocktail consisting of forskolin, ISX9, CHIR99021 I-BET 151, and DAPT. Treating U87MG glioblastoma cells with this cocktail successfully reprogrammed the malignant cells into early neurons over 13 days. The reprogrammed cells displayed morphological and immunofluorescent characteristics associated with neuronal phenotypes. Genetic analysis revealed that the chemical cocktail upregulates the Ngn2, Ascl1, Brn2, and MAP2 genes, resulting in neuronal reprogramming. Furthermore, these cells displayed decreased viability and lacked the ability to form high numbers of tumor-like spheroids. Overall, this study validates the use of a novel small molecule cocktail for reprogramming glioblastoma into nonproliferating neurons.

Different Effect of Sox11 in Retinal Ganglion Cells Survival and Axon Regeneration

Purpose: The present study examines the role of Sox11 in the initial response of retinal ganglion cells (RGCs) to axon damage and in optic nerve regeneration in mouse. Methods: Markers of retinal injury were identified using the normal retina database and optic nerve crush (ONC) database on GeneNetwork² (www.genenetwork.org). One gene, Sox11, was highly upregulated following ONC. We examined the role of this transcription factor, Sox11, following ONC and optic nerve regeneration in mice. In situ hybridization was performed using the Affymetrix 2-plex Quantigene View RNA In Situ Hybridization Tissue Assay System. Sox11 was partially knocked out by intravitreal injection of AAV2-CMV-Cre-GFP in Sox11 ^f/f mice. Optic nerve regeneration model used Pten knockdown. Mice were perfused and the retinas and optic nerves were dissected and examined for RGC survival and axon growth. Results: Sox11 was dramatically upregulated in the retina following ONC injury. The level of Sox11 message increased by approximately eightfold 2 days after ONC. In situ hybridization demonstrated low-level Sox11 message in RGCs and cells in the inner nuclear layer in the normal retina as well as a profound increase in Sox11 message within the ganglion cells following ONC. In Sox11 ^f/f retinas, partially knocking out Sox11 significantly increased RGC survival after ONC as compared to the AAV2-CMV-GFP control group; however, it had little effect on the ability of axon regeneration. Combinatorial downregulation of both Sox11 and Pten resulted in a significant increase in RGC survival as compared to Pten knockdown only. When Pten was knocked down there was a remarkable increase in the number and the length of regenerating axons. Partially knocking out Sox11 in combination with Pten deletion resulted in a fewer regenerating axons. Conclusion: Taken together, these data demonstrate that Sox11 is involved in the initial response of the retina to injury, playing a role in the early attempts of axon regeneration and neuronal survival. Downregulation of Sox11 aids in RGC survival following injury of optic nerve axons, while a partial knockout of Sox11 negates the axon regeneration stimulated by Pten knockdown.

Clinicopathological characteristics of malignant melanomas of the skin and gastrointestinal tract

The present study examined the differences between gastrointestinal melanoma (GM) and skin melanoma (SM). The clinicopathological characteristics, the expression of melanoma stem cell markers nestin, sex determining region Y-box 2 and ATP-binding cassette sub-family B member 5, and the presence of the BRAF^V600E mutation were evaluated in 10 cases of GM and 31 cases of SM. Patients with GM had an increased mean age compared with those with SM (76 vs. 68 years). In addition, GMs were significantly more likely than SMs to be amelanotic (50 vs. 7%; P=0.001) and display round cells (70 vs. 23%; P=0.02). The mitosis rate was also significantly higher in GM compared with SM (P<0.05). The incidence of lymph-node metastasis (60 vs. 32%; P<0.05) and distant metastasis (10 vs. 6.5%, P=0.02) was significantly higher in GMs compared with SMs. The expression of stem cell markers did not differ significantly between groups, however, in the SM group advanced-stage disease was associated with a significantly higher expression of nestin than early-stage disease (P<0.05). Immunohistochemically, the expression of BRAF^V600E was significantly lower in GMs compared with in SMs (1.0 vs. 3.3; P=0.01). These findings indicate that the identification of these features may aid in the diagnosis of GM and SM, as well as contribute to the development of novel targeted therapies against GM.

The role of sex-determining region Y-box 6 in melanogenesis in alpaca melanocytes

BACKGROUND

Sex-determining region Y-box (SOX) proteins function as transcriptional regulators. The derivation of melanocytes from nerve crest cells has been reported to depend on SOX proteins, including SOX10 and SOX5. Whether SOX6 is expressed and has a functional role in melanocytes is unknown.

OBJECTIVE

We aimed to study the effect of transcription factor SOX6 on melanogenesis in alpaca melanocytes.

METHODS

We verified the role of SOX6 in melanogenesis by overexpressing and inhibiting SOX6 in melanocytes. Co-immunoprecipitation (co-IP) experiments were performed to further explore the function of SOX6 in melanogenesis and its mechanism of melanin production. We found that SOX6 interacted with cyclin-dependent kinase （CDK5）, β-catenin, and Cyclin D1.

RESULTS

Bioinformatics analysis suggested that SOX6 has a phosphorylation site for CDK5, which regulates melanogenesis, suggesting that SOX6 might play a role in melanogenesis. Co-IP experiments indicated that SOX6 interacted with CDK5, β-catenin, and Cyclin D1. Quantitative real-time polymerase chain reaction and western blot analyses of SOX6-overexpressing melanocytes revealed increased mRNA and protein expression of Cyclin D1, CDK5, microphthalmia transcription factor (MITF), tyrosinase (TYR), tyrosine related protein-1 (TYRP1), and dopachrome-tautomerase (DCT), whereas β-catenin levels decreased in SOX6-overexpressing melanocytes. The opposite results were observed upon SOX6 knockdown. The melanin content was significantly increased or decreased, respectively, by SOX6 overexpression or knockdown.

CONCLUSION

Our results suggest that SOX6 might enhance melanogenesis by binding with β-catenin to increase Cyclin D1 and MITF expression.

Diversity among POU transcription factors in chromatin recognition and cell fate reprogramming

The POU (Pit-Oct-Unc) protein family is an evolutionary ancient group of transcription factors (TFs) that bind specific DNA sequences to direct gene expression programs. The fundamental importance of POU TFs to orchestrate embryonic development and to direct cellular fate decisions is well established, but the molecular basis for this activity is insufficiently understood. POU TFs possess a bipartite 'two-in-one' DNA binding domain consisting of two independently folding structural units connected by a poorly conserved and flexible linker. Therefore, they represent a paradigmatic example to study the molecular basis for the functional versatility of TFs. Their modular architecture endows POU TFs with the capacity to accommodate alternative composite DNA sequences by adopting different quaternary structures. Moreover, associations with partner proteins crucially influence the selection of their DNA binding sites. The plentitude of DNA binding modes confers the ability to POU TFs to regulate distinct genes in the context of different cellular environments. Likewise, different binding modes of POU proteins to DNA could trigger alternative regulatory responses in the context of different genomic locations of the same cell. Prominent POU TFs such as Oct4, Brn2, Oct6 and Brn4 are not only essential regulators of development but have also been successfully employed to reprogram somatic cells to pluripotency and neural lineages. Here we review biochemical, structural, genomic and cellular reprogramming studies to examine how the ability of POU TFs to select regulatory DNA, alone or with partner factors, is tied to their capacity to epigenetically remodel chromatin and drive specific regulatory programs that give cells their identities.

Fatty Acid Synthase and Acetyl-CoA Carboxylase Are Expressed in Nodal Metastatic Melanoma But Not in Benign Intracapsular Nodal Nevi

BACKGROUND

Melanoma is a potentially lethal form of skin cancer for which the current standard therapy is complete surgical removal of the primary tumor followed by sentinel lymph node biopsy when indicated. Histologic identification of metastatic melanoma in a sentinel node has significant prognostic and therapeutic implications, routinely guiding further surgical management with regional lymphadenectomy. While melanocytes in a lymph node can be identified by routine histopathologic and immunohistochemical examination, the distinction between nodal nevus cells and melanoma can be morphologically problematic. Previous studies have shown that malignant melanoma can over-express metabolic genes such as fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC). This immunohistochemical study aims to compare the utility of FASN and ACC in differentiating sentinel lymph nodes with metastatic melanomas from those with benign nodal nevi in patients with cutaneous melanoma.

MATERIALS AND METHODS

Using antibodies against FASN and ACC, 13 sentinel lymph nodes from 13 patients with metastatic melanoma and 14 lymph nodes harboring benign intracapsular nevi from 14 patients with cutaneous malignant melanoma were examined. A diagnosis of nodal melanoma was based on cytologic atypia and histologic comparison with the primary melanoma. All nodal nevi were intracapsular and not trabecular. Immunohistochemistry for Melan-A, S100, human melanoma black 45 (HMB45), FASN, and ACC were performed. The percentage of melanocytes staining with HMB45, FASN, and ACC was determined and graded in 25% increments; staining intensity was graded as weak, moderate, or strong.

RESULTS

All metastatic melanomas tested had at least 25% tumor cell staining for both FASN and ACC. Greater than 75% of the tumor cells stained with FAS in 7/13 cases and for ACC in 5/12 cases. Intensity of staining was variable; strong staining for FASN and ACC was observed in 69% and 50% of metastatic melanoma, respectively. HMB45 was negative in 40% of nodal melanoma cases all of which stained with FASN and ACC. Capsular nevi were uniformly negative for FASN, ACC, and HMB45 immunoreactivity.

CONCLUSIONS

All metastatic melanoma cases involving sentinel lymph nodes were positive for FASN and ACC while no staining was observed in intracapsular nevi. These findings suggest that FASN and ACC could be used as valuable ancillary stains in the distinction between nodal nevi and metastatic melanoma.

FoxO proteins or loss of functional p53 maintain stemness of glioblastoma stem cells and survival after ionizing radiation plus PI3K/mTOR inhibition

Dual PI3K/mTOR inhibitors do not effectively radiosensitize glioblastoma multiforme stem cells (GBM-SCs), but p53-proficient GBM-SCs are more responsive than p53-deficient ones. Here, we found that p53-proficient, but not p53-deficient, GBM-SCs lost stemness and differentiated after γ-irradiation combined with PI3K/mTOR inhibition; expression of FoxO proteins was also lost. FoxO overexpression inhibited the loss of stem cell markers under these conditions. Combined, but not single, FoxO1/3 deletion or pharmacological inhibition of FoxO transcriptional activity strongly reduced stem and progenitor marker expression, particularly that of Sox2. Binding of FoxO1 and FoxO3 to the sox2 regulatory regions was also found. However, combined FoxO1/3 knockdown strongly reduced self-renewal and post-treatment survival only in p53-proficient GBM-SCs. This suggests that FoxO1 and FoxO3 are crucial for functional stemness and post-treatment survival mainly in p53-proficient but not in p53-deficient GBM-SCs, and that these functions can be maintained through the loss of DNA damage-responsive p53 instead.

Defined Culture Conditions Accelerate Small-molecule-assisted Neural Induction for the Production of Neural Progenitors from Human-induced Pluripotent Stem Cells

The use of defined conditions for derivation, maintenance, and differentiation of human-induced pluripotent stem cells (hiPSCs) provides a superior experimental platform to discover culture responses to differentiation cues and elucidate the basic requirements for cell differentiation and fate restriction. Adoption of defined systems for reprogramming, undifferentiated growth, and differentiation of hiPSCs was found to significantly influence early stage differentiation signaling requirements and temporal kinetics for the production of primitive neuroectoderm. The bone morphogenic protein receptor agonist LDN-193189 was found to be necessary and sufficient for neural induction in a monolayer system with landmark antigens paired box 6 and sex-determining region Y-box 1 appearing within 72 h. Preliminary evidence suggests this neuroepithelium was further differentiated to generate ventral spinal neural progenitors that produced electrophysiologically active neurons in vitro, maintaining viability posttransplantation in an immunocompromised host. Our findings support current developments in the field, demonstrating that adoption of defined reagents for the culture and manipulation of pluripotent stem cells is advantages in terms of simplification and acceleration of differentiation protocols, which will be critical for future clinical translation.

Morphine delays neural stem cells differentiation by facilitating Nestin overexpression

BACKGROUND

Morphine is used as an analgesic although it causes important secondary effects. These effects are triggered by several mechanisms leading to the dysregulation of gene expression. Here we aimed to study these alterations on neural stem cells (NSC) during CNS development.

METHODS

AB strain and tg nestin:GFP zebrafish embryos, zebrafish primary neuron culture and mouse embryonic stem cells were used to assess the effect of morphine by qPCR, time lapse microscopy and western blot. ChIP-qPCR and bisulfite conversion assay were performed to determine the changes exerted by morphine in a Nestin candidate enhancer.

RESULTS

Morphine increases GFP in nestin:GFP embryos and overexpresses the NSC marker Nestin. Morphine also exerts a hyperacetylation effect on H3K27 and decreases DNA methylation within a region located 18 Kb upstream nestin transcription starting site. Here, a binding site for the transcription factor complex Sox2/Oct4/Nanog was predicted. These factors are also upregulated by morphine. Besides, morphine increases the histone acetyl transferase p300. The inhibition of p300 activity decreases Nestin.

CONCLUSIONS

Morphine facilitates Nestin increase by several mechanisms which include hyperacetylation of H3K27, decreased DNA methylation and the overexpression of the transcription factors sox2, oct4 and nanog. It has also been demonstrated that nestin levels depend on p300 activity. The facilitated Nestin expression delays the normal differentiation of neural stem cells.

GENERAL SIGNIFICANCE

The present work provides novel evidence of the effects induced by morphine in the normal differentiation of NSCs, altering Nestin through changes on p300, H3K27ac, DNA methylation and Oct4, Sox2, and Nanog.

SoxC transcription factors: multifunctional regulators of neurodevelopment

During development, generation of neurons is coordinated by the sequential activation of gene expression programs by stage- and subtype-specific transcription factor networks. The SoxC group transcription factors, Sox4 and Sox11, have recently emerged as critical components of this network. Initially identified as survival and differentiation factors for neural precursors, SoxC factors have now been linked to a broader array of developmental processes including neuronal subtype specification, migration, dendritogenesis and establishment of neuronal projections, and are now being employed in experimental strategies for neuronal replacement and axonal regeneration in the diseased central nervous system. This review summarizes the current knowledge regarding SoxC factor function in CNS development and disease and their promise for regeneration.

SOX10-MITF pathway activity in melanoma cells

Melanoma is one of the most dangerous and lethal skin cancers, with a considerable metastatic potential and drug resistance. It involves a malignant transformation of melanocytes. The exact course of events in which melanocytes become melanoma cells remains unclear. Nevertheless, this process is said to be dependent on the occurrence of cells with the phenotype of progenitor cells - cells characterized by expression of proteins such as nestin, CD-133 or CD-271. The development of these cells and their survival were found to be potentially dependent on the neural crest stem cell transcription factor SOX10. This is just one of the possible roles of SOX10, which contributes to melanomagenesis by regulating the SOX10-MITF pathway, but also to melanoma cell survival, proliferation and metastasis formation. The aim of this review is to describe the broad influence of the SOX10-MITF pathway on melanoma cells.

Restore the brake on tumor progression

Sonic hedgehog (Shh) signaling plays a key role in regulation of normal development. The negative feedback mechanism mediated by the transcriptional factor, Gli3, acts to finely tune Shh signaling, providing tight control of normal developmental processes. Hyperactivation of Shh signaling often leads to many human malignancies, including basal cell carcinoma and medulloblastoma (MB). However, how tumor cells sustain the aberrant activation of Shh signaling is still not completely understood. We recently revealed that during MB formation, tumor cells express Nestin, a type VI intermediate filament protein, which maintains uncontrolled Shh signaling by abolishing negative feedback by Gli3. Therefore, Nestin expression is a necessary step for MB formation. These findings highlight the novel function of Nestin in regulating Shh signaling, as well as the important role of a disrupted negative feedback mechanism in MB tumorigenesis. Further, restoration of the intrinsic negative feedback by repressing Nestin expression represents a promising approach to treat MB as well as other Shh signaling associated malignancies.

The influence of rAAV2-mediated SOX2 delivery into neonatal and adult human RPE cells; a comparative study

Cell replacement is a promising therapy for degenerative diseases like age-related macular degeneration (AMD). Since the human retina lacks regeneration capacity, much attention has been directed toward persuading for cells that can differentiate into retinal neurons. In this report, we have investigated reprogramming of the human RPE cells and concerned the effect of donor age on the cellular fate as a critical determinant in reprogramming competence. We evaluated the effect of SOX2 over-expression in human neonatal and adult RPE cells in cultures. The coding region of human SOX2 gene was cloned into adeno-associated virus (AAV2) and primary culture of human neonatal/adult RPE cells were infected by recombinant virus. De-differentiation of RPE to neural/retinal progenitor cells was investigated by quantitative real-time PCR and ICC for neural/retinal progenitor cells' markers. Gene expression analysis showed 80-fold and 12-fold over-expression for SOX2 gene in infected neonatal and adult hRPE cells, respectively. The fold of increase for Nestin in neonatal and adult hRPE cells was 3.8-fold and 2.5-fold, respectively. PAX6 expression was increased threefold and 2.5-fold in neonatal/adult treated cultures. Howbeit, we could not detect rhodopsin, and CHX10 expression in neonatal hRPE cultures and expression of rhodopsin in adult hRPE cells. Results showed SOX2 induced human neonatal/adult RPE cells to de-differentiate toward retinal progenitor cells. However, the increased number of PAX6, CHX10, Thy1, and rhodopsin positive cells in adult hRPE treated cultures clearly indicated the considerable generation of neuro-retinal terminally differentiated cells.

Reprint of: Importins in the maintenance and lineage commitment of ES cells

The nucleus of a eukaryotic cell is separated from the cytoplasm by a nuclear envelope, and nuclear pores within the envelope facilitate nucleocytoplasmic transport and the exchange of information. Gene regulation is a key component of biological activity regulation in the cell. Transcription factors control the expression levels of various genes that are necessary for the maintenance or conversion of cellular states during animal development. Because transcription factor activities determine the extent of transcription of target genes, the number of active transcription factors must be tightly regulated. In this regard, the nuclear translocation of a transcription factor is an important determinant of its activity. Therefore, it is becoming clear that the nucleocytoplasmic transport machinery is involved in cell differentiation and organism development. This review examines the regulation of transcription factors by the nucleocytoplasmic transport machinery in ES cells.

Isolation, characterization, and differentiation of multipotent neural progenitor cells from human cerebrospinal fluid in fetal cystic myelomeningocele

Despite benefits of prenatal in utero repair of myelomeningocele, a severe type of spina bifida aperta, many of these patients will still suffer mild to severe impairment. One potential source of stem cells for new regenerative medicine-based therapeutic approaches for spinal cord injury repair is neural progenitor cells (NPCs) in cerebrospinal fluid (CSF). To this aim, we extracted CSF from the cyst surrounding the exposed neural placode during the surgical repair of myelomeningocele in 6 fetuses (20 to 26weeks of gestation). In primary cultured CSF-derived cells, neurogenic properties were confirmed by in vitro differentiation into various neural lineage cell types, and NPC markers expression (TBR2, CD15, SOX2) were detected by immunofluorescence and RT-PCR analysis. Differentiation into three neural lineages was corroborated by arbitrary differentiation (depletion of growths factors) or explicit differentiation as neuronal, astrocyte, or oligodendrocyte cell types using specific induction mediums. Differentiated cells showed the specific expression of neural differentiation markers (βIII-tubulin, GFAP, CNPase, oligo-O1). In myelomeningocele patients, CSF-derived cells could become a potential source of NPCs with neurogenic capacity. Our findings support the development of innovative stem-cell-based therapeutics by autologous transplantation of CSF-derived NPCs in damaged spinal cords, such as myelomeningocele, thus promoting neural tissue regeneration in fetuses.

ChIP-seq analysis of genomic binding regions of five major transcription factors highlights a central role for ZIC2 in the mouse epiblast stem cell gene regulatory network

To obtain insight into the transcription factor (TF)-dependent regulation of epiblast stem cells (EpiSCs), we performed ChIP-seq analysis of the genomic binding regions of five major TFs. Analysis of in vivo biotinylated ZIC2, OTX2, SOX2, POU5F1 and POU3F1 binding in EpiSCs identified several new features. (1) Megabase-scale genomic domains rich in ZIC2 peaks and genes alternate with those rich in POU3F1 but sparse in genes, reflecting the clustering of regulatory regions that act at short and long-range, which involve binding of ZIC2 and POU3F1, respectively. (2) The enhancers bound by ZIC2 and OTX2 prominently regulate TF genes in EpiSCs. (3) The binding sites for SOX2 and POU5F1 in mouse embryonic stem cells (ESCs) and EpiSCs are divergent, reflecting the shift in the major acting TFs from SOX2/POU5F1 in ESCs to OTX2/ZIC2 in EpiSCs. (4) This shift in the major acting TFs appears to be primed by binding of ZIC2 in ESCs at relevant genomic positions that later function as enhancers following the disengagement of SOX2/POU5F1 from major regulatory functions and subsequent binding by OTX2. These new insights into EpiSC gene regulatory networks gained from this study are highly relevant to early stage embryogenesis.