Spicing up endogenous neural stem cells: aromatic-turmerone offers new possibilities for tackling neurodegeneration

There is a growing interest in the therapeutic utility of compounds derived from Curcuma longa, an herb of the Zingiberaceae family that has been part of traditional medicine for centuries. Recent reports suggest that bioactive compounds isolated from the rhizome of these plants can address two key aspects of brain injury following stroke that must be dealt with for functional recovery to occur: the moderation of neuroinflammation, and the mobilization of endogenous stem cells resident in the nervous system. Defining their mechanism of action remains a question, but emerging evidence may point towards one shared with more classic modulators of neural stem cell proliferation and survival

The STAT3-Ser/Hes3 signaling axis in cancer

Disrupting the regenerative capacity of tumorigenic cells is a major focus in medicine. These regenerative properties are carried by a subpopulation of cells within the tumor, termed cancer stem cells. Current therapies don't effectively tackle the disease suggesting these cells employ yet unidentified molecular mechanisms allowing them to evade targeting. Recent observations in neural stem cells reveal an extraordinary plasticity in the signaling pathways they utilize to grow. These findings are being extended to the cancer stem cell field, illuminating conceptually novel treatment strategies. Tumorigenic cells can make use of distinct, even opposing pathways, including JAK/STAT and the non-canonical STAT3-Ser/Hes3 signaling axis. This plasticity may not be confined to the cancer stem cell population, but may be shared by various cell types within the tumor, blurring the line distinguishing cancer stem cells from other tumor cell types. The implications to anti-cancer medicine are highly significant, since these findings demonstrate that inhibiting one cell growth pathway may actually enhance the activity of alternative ones. Drug discovery programs will also benefit from these concepts

Hes3 is expressed in the adult pancreatic islet and regulates gene expression, cell growth, and insulin release

The transcription factor Hes3 is a component of a signaling pathway that supports the growth of neural stem cells with profound consequences in neurodegenerative disease models. Here we explored whether Hes3 also regulates pancreatic islet cells. We showed that Hes3 is expressed in human and rodent pancreatic islets. In mouse islets it co-localizes with alpha and beta cell markers. We employed the mouse insulinoma cell line MIN6 to perform in vitro characterization and functional studies in conditions known to modulate Hes3 based upon our previous work using neural stem cell cultures. In these conditions, cells showed elevated Hes3 expression and nuclear localization, grew efficiently, and showed higher evoked insulin release responses, compared with serum-containing conditions. They also exhibited higher expression of the transcription factor Pdx1 and insulin. Furthermore, they were responsive to pharmacological treatments with the GLP-1 analog Exendin-4, which increased nuclear Hes3 localization. We employed a transfection approach to address specific functions of Hes3. Hes3 RNA interference opposed cell growth and affected gene expression as revealed by DNA microarrays. Western blotting and PCR approaches specifically showed that Hes3 RNA interference opposes the expression of Pdx1 and insulin. Hes3 overexpression (using a Hes3-GFP fusion construct) confirmed a role of Hes3 in regulating Pdx1 expression. Hes3 RNA interference reduced evoked insulin release. Mice lacking Hes3 exhibited increased islet damage by streptozotocin. These data suggest roles of Hes3 in pancreatic islet function

Cholera Toxin Regulates a Signaling Pathway Critical for the Expansion of Neural Stem Cell Cultures from the Fetal and Adult Rodent Brains

Background: New mechanisms that regulate neural stem cell (NSC) expansion will contribute to improved assay systems and the emerging regenerative approach that targets endogenous stem cells. Expanding knowledge on the control of stem cell self renewal will also lead to new approaches for targeting the stem cell population of cancers. Methodology/Principal Findings: Here we show that Cholera toxin regulates two recently characterized NSC markers, the Tie2 receptor and the transcription factor Hes3, and promotes the expansion of NSCs in culture. Cholera toxin increases immunoreactivity for the Tie2 receptor and rapidly induces the nuclear localization of Hes3. This is followed by powerful cultured NSC expansion and induction of proliferation both in the presence and absence of mitogen. Conclusions/Significance: Our data suggest a new cell biological mechanism that regulates the self renewal and differentiation properties of stem cells, providing a new logic to manipulate NSCs in the context of regenerative disease and cancer

Hes3 expression in the adult mouse brain is regulated during demyelination and remyelination

Hes3 is a component of the STAT3-Ser/Hes3 Signaling Axis controlling the growth and survival of neural stem cells and other plastic cells. Pharmacological activation of this pathway promotes neuronal rescue and behavioral recovery in models of ischemic stroke and Parkinson's disease. Here we provide initial observations implicating Hes3 in the cuprizone model of demyelination and remyelination. We focus on the subpial motor cortex of mice because we detected high Hes3 expression. This area is of interest as it is impacted both in human demyelinating diseases and in the cuprizone model. We report that Hes3 expression is reduced at peak demyelination and is partially restored within 1 week after cuprizone withdrawal. This raises the possibility of Hes3 involvement in demyelination/remyelination that may warrant additional research. Supporting a possible role of Hes3 in the maintenance of oligodendrocyte markers, a Hes3 null mouse strain shows lower levels of myelin basic protein in undamaged adult mice, compared to wild-type controls. We also present a novel method for culturing the established oligodendrocyte progenitor cell line oli-neu in a manner that maintains Hes3 expression as well as its self-renewal and differentiation potential, offering an experimental tool to study Hes3. Based upon this approach, we identify a Janus kinase inhibitor and dbcAMP as powerful inducers of Hes3 gene expression. We provide a new biomarker and cell culture method that may be of interest in demyelination/remyelination research

Expression of the transcription factor Hes3 in the mouse and human ocular surface, and in pterygium

Purpose: In this work we examined the presence of the neural stem cell biomarker Hairy and Enhancer of Split 3 (Hes3) in the anterior eye segment and in the aberrant growth condition of the conjunctiva pterygium. Further, we studied the response of Hes3 to irradiation. Materials and methods: Adult mouse and human corneoscleral junction and conjunctiva, as well as human pterygium were prepared for immunohistochemical detection of Hes3 and other markers. Total body irradiation was used to study the changes in the pattern of Hes3 expression. Results: The adult rodent and human eye as well as pterygium, contain a population of cells expressing Hes3. In the human eye, Hes3-expressing (Hes3+) cells are found predominantly in the subconjunctival space spanning over the limbus where they physically associate with blood vessels. The cytoarchitecture of Hes3 + cells is similar to those previously observed in the adult central nervous system. Furthermore, irradiation reduces the number of Hes3 + cells in the subconjunctival space. In contrast, irradiation strongly promotes the nuclear localization of Hes3 in the ciliary body epithelium. Conclusions: Our results suggest that a recently identified signal transduction pathway that regulates neural stem cells and glioblastoma cancer stem cells also operates in the ocular surface, ciliary body, and in pterygium

Hes3 regulates cell number in cultures from glioblastoma multiforme with stem cell characteristics

Tumors exhibit complex organization and contain a variety of cell populations. The realization that the regenerative properties of a tumor may be largely confined to a cell subpopulation (cancer stem cell) is driving a new era of anti-cancer research. Cancer stem cells from Glioblastoma Multiforme tumors express markers that are also expressed in non-cancerous neural stem cells, including nestin and Sox2. We previously showed that the transcription factor Hes3 is a marker of neural stem cells, and that its expression is inhibited by JAK activity. Here we show that Hes3 is also expressed in cultures from glioblastoma multiforme which express neural stem cell markers, can differentiate into neurons and glia, and can recapitulate the tumor of origin when transplanted into immunocompromised mice. Similar to observations in neural stem cells, JAK inhibits Hes3 expression. Hes3 RNA interference reduces the number of cultured glioblastoma cells suggesting a novel therapeutic strategy

Angiogenic Factors Stimulate Growth of Adult Neural Stem Cells

The ability to grow a uniform cell type from the adult central nervous system (CNS) is valuable for developing cell therapies and new strategies for drug discovery. The adult mammalian brain is a source of neural stem cells (NSC) found in both neurogenic and non-neurogenic zones but difficulties in culturing these hinders their use as research tools.Here we show that NSCs can be efficiently grown in adherent cell cultures when angiogenic signals are included in the medium. These signals include both anti-angiogenic factors (the soluble form of the Notch receptor ligand, Dll4) and pro-angiogenic factors (the Tie-2 receptor ligand, Angiopoietin 2). These treatments support the self renewal state of cultured NSCs and expression of the transcription factor Hes3, which also identifies the cancer stem cell population in human tumors. In an organotypic slice model, angiogenic factors maintain vascular structure and increase the density of dopamine neuron processes.We demonstrate new properties of adult NSCs and a method to generate efficient adult NSC cultures from various central nervous system areas. These findings will help establish cellular models relevant to cancer and regeneration