Expression Of P75 Neurotrophin Receptor Research Articles

6-Shogaol attenuates natural aging-induced locomotive and cognitive declines through suppression of p75 neurotrophin receptor in vivo

The present study aimed to investigate the effect of 6-shogaol (6S) treatment on brain senescence. Mice were naturally aged until 25-month-old and treated with 10 mg/kg of 6S for a month. Behavioral tests were performed to measure locomotion and cognitive function. Neuronal damage, synaptic plasticity, neuroinflammation, neurogenesis and p75 neurotrophin receptor (p75NTR) expression were examined by immunohistochemistry or immunofluorescence. 6S treatment improved locomotion during open field test in the aged mice and spontaneous alternation in Y-maze. These data are in line with that 6S administration improved dopaminergic neuronal loss and dopamine signaling and attenuated hippocampal synaptic plasticity in the aged brain. Additionally, 6S treatment reduced striatal and hippocampal microgliosis and astrocytosis but promoted neurogenesis in subventricular zone. Furthermore, 6S treatment reversed the p75NTR expression in the senescent brain. The current findings suggest that 6S can be a functional food for successful aging through brain rejuvenation at the molecular level.

Fasting alters p75NTR and AgRP mRNA expression in rat olfactory bulb and hippocampus

Classic non-homeostatic structures involved in food intake regulation are reciprocally influenced by metabolic signals. Orexigenic peptides expressed in the olfactory bulb (OB) and hippocampus (HP) modulate olfactory processing and memory, respectively. Hypothalamic circuits also modulate feeding behavior by activating and releasing Agouti-related peptide (AgRP) in response to orexigenic signals. An adequate response to fasting requires the expression of p75 neurotrophin receptor (p75NTR) in AgRP neurons. The present study aimed to determine whether there is a role for p75NTR and AgRP in the OB and HP on the feeding behavior of fasted rats. A group of fasted rats (FG) was confronted with a decision-making paradigm in a T-maze containing a standard chow pellet (CP), and the same pellet coated with a phenolic-rich avocado paste extract (AVO) on either end; their OB and HP were then analyzed with histological and molecular tools. FG rats had briefer feeding latencies, as compared to control rats fed ad libitum (median latencies: 55.4 vs 191.7 min, p = 0.032). They also had reduced cell counts in both brain structures, as compared to satiated rats. AgRP mRNA was not expressed in the HP of either group, however, it was found in the OB. p75NTR mRNA was expressed in both brain structures of FG rats. These results suggest that contrasting metabolic states (fasted or satiated) motivate different feeding responses, which are influenced by p75NTR and AgRP mRNA expression in non-homeostatic food intake brain structures.

Susceptibility of aged pericytes to Aβ1‐42 oligomers

AbstractBackgroundAging is associated with increased incidence of Alzheimer’s disease, blood brain barrier breakdown, and increased cellular senescence (Saez‐Atienzar et. al, 2020). Senescence is the permanent arrest of the proliferative state of the cell and is initiated as a result of aging and cellular stress (Martínez‐Cué et.al, 2020). Senescent cells induce production of proinflammatory cytokines. In the brain, chronic inflammation leads to synapse damage and cognitive decline (Saez‐Atienzar et. al, 2020). The objective of this study is to examine the impact of cellular senescence on brain vascular pericytes, which contribute to the regulation of cerebral blood flow.MethodFor this study, both in vitro as well as in vivo experiments were performed. To induce senescence by oxidative stress in vitro in a culture of mouse brain vascular pericytes, 100 uM of hydrogen peroxide was added to culture flasks. Senescence was confirmed in the treated cells via staining for β‐galactosidase, a known biomarker of senescent cells. The next steps for the in vitro aspects of this study include performing western blotting on senescent pericytes to determine if there is a differential expression of pericyte p75 neurotrophin receptor (p75NTR), which has a potential role in the impaired hemodynamic response and cell death in pericytes. Finally, cranial window procedures were performed on 18‐month‐old C57BL/6 mice followed by imaging the live brain tissue with a multiphoton microscope. While imaging, artificial cerebral spinal fluid (control animals) or 72 nM amyloid‐beta (Aβ)1‐42 oligomers were topically delivered to the brain surface to determine if Aβ1‐42 oligomers cause a significant reduction in erythrocyte flow through pericyte covered capillaries.ResultPreliminary data from the β‐galactosidase staining suggest that the hydrogen peroxide is an effective method for inducing senescence in mouse brain vascular pericytes. We have observed a decreased growth rate in cells treated with the hydrogen peroxide, further suggesting senescence in these cells.ConclusionThese findings characterize the impact of Aβ on pericyte contractility and could illuminate the role of senescence and aging on impaired hemodynamic responses because of dysfunctional pericytes.

Ibuprofen promotes p75 neurotrophin receptor expression through modifying promoter methylation and N6-methyladenosine-RNA-methylation in human gastric cancer cells

ABSTRACT It is acknowledged that nonsteroidal anti-inflammatory drugs (NSAIDs) can participate in various signaling pathways, while information about their epigenetic effects are limited. p75NTR (p75 neurotrophin receptor) can inhibit tumor growth by inducing cell cycle arrest and regulating cell cycle arrest and apoptotic cell death. The expression of p75NTR is influenced by epigenetic roles. We explored the effects of ibuprofen on p75NTR expression and investigated whether promoter methylation and N6-methyladenosine (m6A) RNA methylation regulates this process in human gastric cancer cells (SGC7901 and MKN45). Cell lines were treated with ibuprofen 0, 2.5, 5, 10, 20 µM, and then DNA, RNA, and protein were isolated 24 h later. Expression and promoter methylation of p75NTR were detected by RT-qPCR and Western blot. The levels of m6A-p75NTR were measured by RNA immunoprecipitation. We also used RT-qPCR to determine the levels of m6A-related regulators, METTL3, METTL14, ALKBH5, FTO, YTHDC2, and YTHDF1-3. Ibuprofen attenuated p75NTR promoter methylation (p < 0.01) and increased p75NTR level (p < 0.001). Ibuprofen increased m6A-p53 expression (p < 0.01) by promoting the expression of METTL3 (p < 0.01) and METTL14 (p < 0.05); and increased levels of YTHDF1 (p < 0.001), YTHDF3 (p < 0.001), and YTHDC2 (p < 0.01) that finally reinforced p53 translation (p < 0.01). Therefore, our results present that ibuprofen epigenetically increased p75NTR expression by downregulating promoter methylation and upregulating m6A-RNA-methylation in SGC7901 and MKN45 cells. Our study unveils a novel mechanism for p75NTR regulation by NSAIDs and helps the design of treatment targets.

Pilot Investigation on p75ICD Expression in Laryngeal Squamous Cell Carcinoma.

Simple SummaryLaryngeal Squamous Cell Carcinoma (LSCC) is a squamous cancer with 2.4% new diagnoses each year, accounting for 25% of head and neck cancers, and has a high mortality rate. A deeper understanding of key mechanisms and knowledge of the putative target molecules of theranostic relevance are required. The receptor for neurotrophins p75NTR has been shown to be highly expressed in cancer stem cells (CSCs) of squamous epithelia, in LSCC as well as in other cancers. However, whether its cleavage product p75ICD expression, known to finely regulate the survival/death balance in neurons, is also a master regulator in cancer and LSCC in particular has not been directly addressed so far. To resolve this question, we performed a preliminary study using a limited number of LSCC specimens and studied p75ICD presence and expression pattern in LSCC specimens, showing that p75ICD may be a promising target in LSCC, requiring further investigation.We investigated the p75 Neurotrophin Receptor (p75NTR) expression and cleavage product p75NTR Intracellular Domain (p75ICD) as potential oncogenic and metastatic markers in human Laryngeal Squamous Cell Carcinoma (LSCC). p75NTR is highly expressed in Cancer Stem Cells (CSCs) of the laryngeal epithelia and it has been proposed as a marker for stemness, cell migration, and chemo-resistance in different squamous carcinomas. To investigate the clinical significance of p75NTR cleavage products in solid tumors, full-length and cleaved p75NTR expression was analyzed in laryngeal primary tumors from different-stage LSCC patients, diagnosed at the Policlinico Umberto I Hospital. Molecular and histological techniques were used to detect the expressions of p75NTR and p75ICD, and ATP Binding Cassette Subfamily G Member 2 (ABCG2), a CSC marker. We found regulated p75NTR cleavage during squamous epithelial tumor progression and tissue invasion. Our preliminary investigation suggests p75ICD expression and localization as possible features of tumorigenesis and metastaticity. Its co-localization with ABCG2 in squamous cells in the parenchyma invaded by the tumor formation allows us to hypothesize p75NTR and p75ICD roles in tumor invasion and CSC spreading in LSCC patients. These data might represent a starting point for a comprehensive analysis of p75NTR cleavage and of its clinical relevance as a potential molecular LSCC signature, possibly helping diagnosis, and improving prognosis and personalized therapy.

ProBDNF induces sustained elevation of intracellular Ca2+ possibly mediated by TRPM7 channels in rodent microglial cells.

Microglia are intrinsic immune cells that release factors including pro- and anti-inflammatory cytokines, nitric oxide (NO) and neurotrophins following activation in the brain. Elevation of intracellular Ca2+ concentration ([Ca2+ ]i) is important for microglial functions, such as the release of cytokines or NO from activated microglia. Brain-derived neurotrophic factor (BDNF) is a neurotrophin well known for its roles in the activation of microglia. Interestingly, proBDNF, the precursor form of mature BDNF, and mature BDNF elicit opposing neuronal responses in the brain. Mature BDNF induces sustained intracellular Ca2+ elevation through the upregulation of the surface expression of TRPC3 channels in rodent microglial cells. In addition, TRPC3 channels are important for the BDNF-induced suppression of NO production in activated microglia. In this study, we observed that proBDNF and mature BDNF have opposite effects on the relative expression of surface p75 neurotrophin receptor (p75NTR ) in rodent microglial cells. ProBDNF induces a sustained elevation of [Ca2+ ]i through binding to the p75NTR , which is possibly mediated by Rac 1 activation and TRPM7 channels in rodent microglial cells. Flow cytometry showed that proBDNF increased the relative surface expression of TRPM7. Although proBDNF did not affect either mRNA expression of pro- and anti-inflammatory cytokines or the phagocytic activity, proBDNF potentiates the generation of NO induced by IFN-γ and TRPM7 channels could be involved in the proBDNF-induced potentiation of IFN-γ-mediated production of NO. We show direct evidence that rodent microglial cells are able to respond to proBDNF, which might be important for the regulation of inflammatory responses in the brain.

Estradiol Replacement at the Critical Period Protects Hippocampal Neural Stem Cells to Improve Cognition in APP/PS1 Mice

It has been suggested that there is a critical window for estrogen replacement therapy (ERT) in postmenopausal women with Alzheimer’s disease (AD); however, supporting evidence is lacking. To address this issue, we investigated the effective period for estradiol (E2) treatment using a mouse model of AD. Four-month-old female APPswe/PSEN1dE9 (APP/PS1) mice were ovariectomized (OVX) and treated with E2 for 2 months starting at the age of 4 months (early period), 6 months (mid-period), or 8 months (late period). We then evaluated hippocampal neurogenesis, β-amyloid (Aβ) accumulation, telomerase activity, and hippocampal-dependent behavior. Compared to age-matched wild type mice, APP/PS1 mice with intact ovaries showed increased proliferation of hippocampal neural stem cells (NSCs) at 8 months of age and decreased proliferation of NSCs at 10 months of age; meanwhile, Aβ accumulation progressively increased with age, paralleling the reduced survival of immature neurons. OVX-induced depletion of E2 in APP/PS1 mice resulted in elevated Aβ levels accompanied by elevated p75 neurotrophin receptor (p75NTR) expression and increased NSC proliferation at 6 months of age, which subsequently declined; accelerated reduction of immature neurons starting from 6 months of age, and reduced telomerase activity and worsened memory performance at 10 months of age. Treatment with E2 in the early period post-OVX, rather than in the mid or late period, abrogated these effects, and p75NTR inhibition reduced the overproliferation of NSCs in 6-month-old OVX-APP/PS1 mice. Thus, E2 deficiency in young APP/PS1 mice exacerbates cognitive deficits and depletes the hippocampal NSC pool in later life; this can be alleviated by E2 treatment in the early period following OVX, which prevents Aβ/p75NTR-induced NSC overproliferation and preserves telomerase activity.

Monocarboxylate transporter 1 in Schwann cells contributes to maintenance of sensory nerve myelination during aging

Schwann cell (SC)-specific monocarboxylate transporter 1 (MCT1) knockout mice were generated by mating MCT1 f/f mice with myelin protein zero (P0)-Cre mice. P0-Cre+/- , MCT1 f/f mice have no detectable early developmental defects, but develop hypomyelination and reduced conduction velocity in sensory, but not motor, peripheral nerves during maturation and aging. Furthermore, reduced mechanical sensitivity is evident in aged P0-Cre+/- , MCT1 f/f mice. MCT1 deletion in SCs impairs both their glycolytic and mitochondrial functions, leading to altered lipid metabolism of triacylglycerides, diacylglycerides, and sphingomyelin, decreased expression of myelin-associated glycoprotein, and increased expression of c-Jun and p75-neurotrophin receptor, suggesting a regression of SCs to a less mature developmental state. Taken together, our results define the contribution of SC MCT1 to both SC metabolism and peripheral nerve maturation and aging.

Immunomodulatory Effects of the Neuropeptide Pituitary Adenylate Cyclase-Activating Polypeptide in Acute Toxoplasmosis

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) is an endogenous neuropeptide with distinct functions including the regulation of inflammatory processes. PACAP is able to modify the immune response by directly regulating macrophages and monocytes inhibiting the production of inflammatory cytokines, chemokines and free radicals. Here, we analyzed the effect of exogenous PACAP on peripheral immune cell subsets upon acute infection with the parasite Toxoplasma gondii (T. gondii). PACAP administration was followed by diminished innate immune cell recruitment to the peritoneal cavity of T. gondii-infected mice. PACAP did not directly interfere with parasite replication, instead, indirectly reduced parasite burden in mononuclear cell populations by enhancing their phagocytic capacity. Although proinflammatory cytokine levels were attenuated in the periphery upon PACAP treatment, interleukin (IL)-10 and Transforming growth factor beta (TGF-β) remained stable. While PACAP modulated VPAC1 and VPAC2 receptors in immune cells upon binding, it also increased their expression of brain-derived neurotrophic factor (BDNF). In addition, the expression of p75 neurotrophin receptor (p75NTR) on Ly6Chi inflammatory monocytes was diminished upon PACAP administration. Our findings highlight the immunomodulatory effect of PACAP on peripheral immune cell subsets during acute Toxoplasmosis, providing new insights about host-pathogen interaction and the effects of neuropeptides during inflammation.

Removal of p75 Neurotrophin Receptor Expression from Cholinergic Basal Forebrain Neurons Reduces Amyloid-β Plaque Deposition and Cognitive Impairment in Aged APP/PS1 Mice.

The degeneration of cholinergic basal forebrain (cBF) neurons in Alzheimer's disease (AD) leads to the cognitive impairment associated with this condition. cBF neurons express the p75 neurotrophin receptor (p75NTR), which mediates cell death, and the extracellular domain of p75NTR can bind to amyloid beta (Aβ) and promote its degradation. Here, we investigated the contribution of cBF neuronal p75NTR to the progression of AD by removing p75NTR from cholinergic neurons in the APP/PS1 familial AD mouse strain. Conditional loss of p75NTR slowed cognitive decline and reduced both Aβ accumulation into plaques and gliosis. Expression of the amyloid protein precursor and its cleavage enzymes ADAM10 and BACE1 were unchanged. There was also no upregulation of p75NTR in non-cholinergic cell types. This indicates that a direct interaction between cBF-expressed p75NTR and Aβ does not contribute significantly to the regulation of Aβ load. Rather, loss of p75NTR from cBF neurons, which results in increased cholinergic innervation of the cortex, appears to regulate alternative, more dominant, Aβ clearance mechanisms.

The spatiotemporal expression and mineralization regulation of p75 neurotrophin receptor in the early tooth development.

The aim of this study was to investigate the spatiotemporal expression and potential role of p75NTR in tooth morphogenesis and tissue mineralization. The dynamic morphology of the four stages (from the beginning of E12.5 d, then E13.5 d and E15.5 d, to the end of E18.5 d) was observed, and the expressions of p75NTR and Runx2 were traced. The ectomesenchymal stem cells (EMSCs) were harvested in vitro, and the biological characteristics were observed. Moreover, the mineralization capability of EMSCs was evaluated. The relations between p75NTR and ALP, Col-1 and Runx2 were investigated. The morphologic results showed that the dental lamina appeared at E12.5 d, the bud stage at E13.5 d, the cap stage at E15.5 d and the bell stage at E18.5 d. p75NTR and Runx2 showed the similar expression pattern. EMSCs from the four stages showed no significant difference in proliferation. But the positive rate of p75NTR in the E12.5 d cells was significantly lower than that in the other three stages (P<0.05). Moreover, the higher positive rate of p75NTR the cells were, the stronger mineralization capability they showed. p75NTR was well positively correlated with the mineralization-related markers ALP, Col-1 and Runx2, which increased gradually with the mature of dental germs. p75NTR might play an important role in the regulation of tooth morphogenesis, especially dental hard tissue formation.

In vivo antivascular endothelial growth factor treatment induces corneal endothelium apoptosis in rabbits through changes in p75NTR-proNGF pathway.

Intravitreal injection (IVT) of antivascular endothelial growth factor (anti-VEGF) agents is widely used for the treatment of retinal vascular diseases. Recently, the injection of anti-VEGF agents in the ocular anterior chamber has been proposed for the treatment of neovascular glaucoma and potential side effects on the corneal structures have been investigated with contrasting results. Increasing evidence has demonstrated that VEGF inhibition is associated with cellular apoptotic changes and that this effect may be mediated by alterations in nerve growth factor (NGF) pathway. In this study, we demonstrated that anterior chamber injection (IC), but not IVT injection of two different anti-VEGF agents, aflibercept and ranibizumab, affects rabbit corneal endothelium in terms of survival and apoptosis andis associated with changes in endothelial expression of NGF precursor (proNGF) and p75 neurotrophin receptor (p75NTR) receptor.We observed an increase in corneal endothelial cell incorporation of trypan blue and expression of cleaved-caspase 3 (c-Casp3), p75NTR, and RhoA after IC injection of both anti-VEGF drugs when compared with the vehicle. Our results showed that apoptosis induction by aflibercept was more pronounced when compared with that of ranibizumab. Aflibercept also mediated a significant increase in endothelial expression of proNGF when compared with the vehicle. In line with these data, IC administration of both anti-VEGF agents induced the activation of apoptotic signals in endothelial cells, including an increase in c-Casp3, decrease in Bad Ser 112 phosphorylation, and unbalance of AKT phosphorylation.These results demonstrated that administration of anti-VEGF in the anterior chamber of rabbit affects endothelial cell survival by inducing apoptosis through alteration of NGF pathway.

P75 neurotrophin receptor interacts with and promotes BACE1 localization in endosomes aggravating amyloidogenesis.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive deposition of amyloid beta (Aβ) and dysregulation of neurotrophic signaling, causing synaptic dysfunction, loss of memory, and cell death. The expression of p75 neurotrophin receptor is elevated in the brain of AD patients, suggesting its involvement in this disease. However, the exact mechanism of its action is not yet clear. Here, we show that p75 interacts with beta-site amyloid precursor protein cleaving enzyme-1 (BACE1), and this interaction is enhanced in the presence of Aβ. Our results suggest that the colocalization of BACE1 and amyloid precursor protein (APP) is increased in the presence of both Aβ and p75 in cortical neurons. In addition, the localization of APP and BACE1 in early endosomes is increased in the presence of Aβ and p75. An increased phosphorylation of APP-Thr668 and BACE1-Ser498 by c-Jun N-terminal kinase (JNK) in the presence of Aβ and p75 could be responsible for this localization. In conclusion, our study proposes a potential involvement in amyloidogenesis for p75, which may represent a future therapeutic target for AD. Cover Image for this Issue: doi. 10.1111/jnc.14163.

Neurotrophin Receptor p75NTR Regulates Immune Function of Plasmacytoid Dendritic Cells.

Plasmacytoid dendritic cells (pDCs) regulate innate and adaptive immunity. Neurotrophins and their receptors control the function of neuronal tissue. In addition, they have been demonstrated to be part of the immune response but little is known about the effector immune cells involved. We report, for the first time, the expression and immune-regulatory function of the low affinity neurotrophin receptor p75 neurotrophin receptor (p75NTR) by the antigen-presenting pDCs, mediated by toll-like receptor (TLR) 9 activation and differential phosphorylation of interferon regulatory factor 3 and 7. The modulation of p75NTR on pDCs significantly influences disease progression of asthma in an ovalbumin-induced mouse model mediated by the TLR9 signaling pathway. p75NTR activation of pDCs from patients with asthma increased allergen-specific T cell proliferation and cytokine secretion in nerve growth factor concentration-dependent manner. Further, p75NTR activation of pDCs delayed the onset of autoimmune diabetes in RIP-CD80GP mice and aggravated graft-versus-host disease in a xenotransplantation model. Thus, p75NTR signaling on pDCs constitutes a new and critical mechanism connecting neurotrophin signaling and immune response regulation with great therapeutic potential for a variety of immune disorders.

Beneficial Effects of Sulforaphane Treatment in Alzheimer's Disease May Be Mediated through Reduced HDAC1/3 and Increased P75NTR Expression.

Alzheimer's disease is an irreversible, progressive neurodegenerative disorder. The accumulation of Aβ in the brain is thought to play a causative role in the development of cognitive dysfunction in Alzheimer's disease. The p75 neurotrophin receptor is of great importance to protect against the Aβ burden and its expression is regulated by histone acetylation. This study investigated whether the phytochemical sulforaphane, a pan-histone deacetylase inhibitor, up-regulates the p75 neurotrophin receptor expression via affecting histone acetylation in protection against Alzheimer's disease. We found that sulforaphane ameliorated behavioral cognitive impairments and attenuated brain Aβ burden in Alzheimer's disease model mice. Additionally, sulforaphane reduced the expression of histone deacetylase1, 2, and 3, up-regulated p75 neurotrophin receptor, and increased levels of acetylated histone 3 lysine 9 and acetylated histone 4 lysine 12 in the cerebral cortex of Alzheimer's disease model mice as well as in Aβ-exposed SH-SY5Y cells. Furthermore, silencing of histone deacetylase1 and 3, but not histone deacetylase2, gene expression with small interfering RNA caused up-regulation of p75 neurotrophin receptor in SH-SY5Y cells. In conclusion, this study demonstrates that sulforaphane can ameliorate neurobehavioral deficits and reduce the Aβ burden in Alzheimer's disease model mice, and the mechanism underlying these effects may be associated with up-regulation of p75 neurotrophin receptor mediated, apparently at least in part, via reducing the expression of histone deacetylase1 and 3.

P75 neurotrophin receptor: A potential surface marker of tongue squamous cell carcinoma stem cells.

The present study detected p75 neurotrophin receptor (p75NTR) expression in tongue squamous cell carcinoma (TSCC) cell lines, in order to define the biological properties of p75NTR+ cells and to confirm the use of p75NTR+ as a surface marker for TSCC stem cells. p75NTR+ cells were separated from Tca-8113 and CAL-27 TSCC cells by fluorescence-activated cell sorting. Colony formation, MTT and scratch assays, and a tumorigenicity analysis were performed to measure self-renewal and proliferation, multidirectional differentiation, and tumorigenicity of p75NTR+ cells. p75NTR+ cells comprised 3.1 and 1.9% of Tca-8113 and CAL-27 cells (mean of three experiments), respectively, and were more able to form colonies compared with non-sorted cells (P<0.01). In addition, the proportion of p75NTR+ cells generated from monoclonal p75NTR+ cells decreased to 14.5 (Tca-8113) and 5.8% (CAL-27) of cells within 2 weeks, thus suggesting that p75NTR+ cells are able to generate p75NTR+ and p75NTR− cells. Furthermore, p75NTR+ cells exhibited increased proliferation, as evidenced by MTT assay (P<0.01) and had greater metastatic ability according to the scratch assay (P<0.01), compared with non-sorted cells. p75NTR+ cells also exhibited a greater tumorigenic capacity compared with non-sorted cells. In conclusion, p75NTR+ cells isolated from TSCC cell lines possess the characteristics of cancer stem cells; therefore, p75NTR may be considered a useful surface marker for the identification of TSCC stem cells.

Clinical Relevance of a Candidate Stem Cell Marker, p75 Neurotrophin Receptor (p75NTR) Expression in Circulating Tumor Cells.

Despite advances in its diagnosis and multimodal therapies, the prognosis of esophageal squamous cell carcinoma (ESCC) patients remains poor, because of high incidences of metastasis . Recent reports suggested that circulating tumor stem cells (CTSCs), rather than circulating tumor cells (CTCs), were more accurate diagnostic marker for metastasis, because tumor stem cells or cancer stem cells (CSCs) are more responsible for metastasis through processes such as epithelial mesenchymal transition (EMT) and tumor initiation. A neurotrophin receptor p75 (p75NTR) is expressed in a candidate CSC s in ESCC, which possess enhanced tumorigenicity along with strong expression of EMT-related genes. Our recent report using two-color flow cytometry demonstrated that CTC counts based on a combined expression of epithelial cell adhesion molecule (EpCAM) and p75NTR was significantly higher in peripheral blood samples of ESCC patients than healthy controls. In addition, EpCAM + p75NTR+, but not EpCAM + p75NTR- CTC counts, correlated with clinically diagnosed distant metastasis and pathological venous invasion in surgically resected primary ESCC tumors. Malignant cytology of the isolated EpCAM + p75NTR+ cells was microscopically confirmed as well. These results demonstrated that EpCAM + p75NTR+ CTC count was a more accurate diagnostic marker than EpCAM+ CTC count, suggesting the highly metastatic potential of CTCs with p75NTR expression.Investigation using the isolated EpCAM + p75NTR+ CTCs to assess their stem cell properties may shed light on their roles in tumor metastasis in ESCC.Further investigations based on large-scale prospective studies with long term follow up may provide us with evidences for its clinical use.

Characterization of p75 neurotrophin receptor expression in human dental pulp stem cells

Human adult dental pulp stem cells (DPSC) are a heterogeneous stem cell population, which are able to differentiate down neural, chondrocyte, osteocyte and adipocyte lineages. We studied the expression pattern of p75 neurotrophin receptors (p75NTR), a marker of neural stem cells, within human DPSC populations from eight donors. p75NTR are expressed at low levels (<10%) in DPSC. Importantly, p75+ DPSC represent higher expression levels of SOX1 (neural precursor cell marker), SOX2 (cell pluripotency marker) and nestin (neural stem cell marker) in comparison to p75− DPSC. Our results suggest that p75+ hDPSC may denote a subpopulation with greater neurogenic potential.

Expression of p75 neurotrophin receptor during the mineralization of ectomesenchymal stem cells in vitro

To investigate the mineralized capacities of ectomesenchymal stem cells (EMSC) from facial process of Sprague Dawley(SD) rat embryo of different age in vitro and the expression of p75 neurotrophin receptor(p75NTR) in this process. The stem cell surface antigens of EMSC from 12.5 d, 15.5 d and 18.5 d SD rat embryonic facial process were tested by flow cytometry technology. E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were incubated under mineralization induction and analysed by alkaline phosphatase(ALP) staining on day 7(d7) and alizarin red staining on day 21(d21). Expression changes of Runt-related transcription factor-2(RUNX2), collagen Ⅰ (Col Ⅰ) and p75NTR in each group were measured using Western blotting and real time(RT)-PCR on day 0(d0), day 7(d7), day 14(d14) and day 21(d21). The expression of the special substances CD29, CD146 and p75NTR in E12.5 d EMSC, E15.5 d EMSC and E18.5 d EMSC were positive, and the expression of CD45 was negative. The expression level of p75NTR in E18.5 d EMSC(84.04%) was much higher than that of E12.5 d EMSC (22.53%) and E15.5 d EMSC(81.43%). The mineralized capacities of E18.5 d EMSC was stronger than that of E12.5 d EMSC and E15.5 d EMSC. The higher expression of RUNX2, Col Ⅰ in E18.5 d EMSC(RUNX2: 1.92±0.20, Col Ⅰ: 1.85±0.66) was found compared with E12.5 d EMSC(RUNX2: 0.38±0.02, Col Ⅰ: 0.33± 0.94) and E15.5 d EMSC(RUNX2: 0.72±0.22, Col Ⅰ: 0.64±0.07) (P<0.05), and p75NTR in the E18.5 d EMSC experimental group(E12.5 d: 0.79±0.23, E15.5 d: 0.84±0.29, E18.5 d: 1.35±0.22) was significantly higher than the in control group(E12.5 d: 0.42±0.12, E15.5 d: 0.43±0.13, E18.5 d: 0.48±0.15)(P<0.05). RT-PCR further proved the results of the Western blotting. p75NTR participated in the mineralization differentiation of EMSC. E18.5 d EMSC had a higher expression of p75NTR and stronger mineralization capacity and was the ideal engineering seed cells.

Schwann-like cells differentiated from human dental pulp stem cells combined with a pulsed electromagnetic field can improve peripheral nerve regeneration.

The purpose of this study was to investigate the effect of Schwann-like cells combined with pulsed electromagnetic field (PEMF) on peripheral nerve regeneration. Schwann-like cells were derived from human dental pulp stem cells (hDPSCs) and verified with CD104, S100, glial fibrillary acidic protein (GFAP), laminin, and P75NTR immunocytochemistry. Gene expression of P75NTR and S100 were analyzed. Male Sprague-Dawley rats (200-250g, 6-week-old) were divided into seven groups (n = 10 each): control, sham, PEMF, hDPSCs, hDPSCs + PEMF, Schwann-like cells, Schwann-like cells + PEMF. Cells were transplanted (1 × 106 /10µl/rat) at crush-injury site or combined with PEMF (50 Hz, 1 h/day, 1 mT). Nerve regeneration was evaluated with functional test, histomorphometry and retrograde labelled neurons. Schwann-like cells expressed CD104, S100, GFAP, laminin, and p75 neurotrophin receptor (P75NTR ). P75NTR and S100 mRNA expression was highest in Schwann-like cells + PEMF group, which also showed increased Difference and Gap scores. Axons and retrograde labeled neurons increased in all treatment groups. Schwann-like cells, hDPSCs with or without PEMF, and PEMF only improved peripheral nerve regeneration. Schwann-like cells + PEMF showed highest regeneration ability; PEMF has additive effect on hDPSCs, Schwann-like cell in vitro and nerve regeneration ability after transplantation in vivo. Bioelectromagnetics. 37:163-174, 2016. © 2016 Wiley Periodicals, Inc.