Non-conventional Axonal Organelles Control TRPM8 Ion Channel Trafficking and Peripheral Cold Sensing.

TRPM8 is the main ion channel responsible for cold transduction in the somatosensory system. Nerve terminal availability of TRPM8 determines cold sensitivity, but how axonal secretory organelles control channel delivery remains poorly understood. Here we examine the distribution of TRPM8 and trafficking organelles in cold-sensitive peripheral axons and disrupt trafficking by targeting the ARF-GEF GBF1 pharmacologically or the small GTPase RAB6 by optogenetics. In axons of the sciatic nerve, inhibition of GBF1 interrupts TRPM8 trafficking and increases association with the trans-Golgi network, LAMP1, and Golgi satellites, which distribute profusely along the axonal shaft. Accordingly, both TRPM8-dependent ongoing activity and cold-evoked responses reversibly decline upon GBF1 inhibition in nerve endings of corneal cold thermoreceptors. Inhibition of RAB6, which also associates to Golgi satellites, decreases cold-induced responses in vivo. Our results support a non-conventional axonal trafficking mechanism controlling the availability of TRPM8 in axons and cold sensitivity in the peripheral nervous system.

Human olfactory mesenchymal stromal cells co-expressing horizontal basal and ensheathing cell proteins in culture. / Las células mesenquimales del estroma olfatorio humano coexpresan proteínas de las células basales horizontales y de recubrimiento neural en cultivo.

INTRODUCTION: The olfactory neuro-epithelium has an intrinsic capability of renewal during lifetime provided by the existence of globose and horizontal olfactory precursor cells. Additionally, mesenchymal stromal olfactory cells also support the homeostasis of the olfactory mucosa cell population. Under in vitro culture conditions with Dulbecco modified eagle/F12 medium supplemented with 10% fetal bovine serum, tissue biopsies from upper turbinate have generated an adherent population of cells expressing mainly mesenchymal stromal phenotypic markers. A closer examination of these cells has also found co-expression of olfactory precursors and ensheathing cell phenotypic markers. These results were suggestive of a unique property of olfactory mesenchymal stromal cells as potentially olfactory progenitor cells. OBJECTIVE: To study whether the expression of these proteins in mesenchymal stromal cells is modulated upon neuronal differentiation. MATERIALS AND METHODS: We observed the phenotype of olfactory stromal cells under DMEM/F12 plus 10% fetal bovine serum in comparison to cells from spheres induced by serum-free medium plus growth factors inducers of neural progenitors. RESULTS: The expression of mesenchymal stromal (CD29+, CD73+, CD90+, CD45-), horizontal basal (ICAM-1/CD54+, p63+, p75NGFr+), and ensheathing progenitor cell (nestin+, GFAP+) proteins was determined in the cultured population by flow cytometry. The determination of Oct 3/4, Sox-2, and Mash-1 transcription factors, as well as the neurotrophins BDNF, NT3, and NT4 by RT-PCR in cells, was indicative of functional heterogeneity of the olfactory mucosa tissue sample. CONCLUSIONS: Mesenchymal and olfactory precursor proteins were downregulated by serum-free medium and promoted differentiation of mesenchymal stromal cells into neurons and astroglial cells.

Introducción. El recambio celular del neuroepitelio olfatorio ocurre durante la vida del individuo gracias a precursores olfatorios. Además, las células mesenquimales del estroma también contribuyen a la homeostasis de la mucosa. Cuando un explante de una biopsia de mucosa se cultiva en un medio esencial mínimo, se genera una población predominante de células adherentes que expresan proteínas típicas de las células mesenquimales del estroma. La coexpresión de marcadores fenotípicos de precursores olfatorios y de células del recubrimiento del nervio olfatorio constituiría una propiedad única de las células mesenquimales del estroma. Objetivo. Determinar si la diferenciación celular de las células mesenquimales hacia fenotipos neurales modula la expresión de los marcadores mesenquimales característicos. Materiales y métodos. Se compararon las células aisladas de la mucosa olfatoria en un medio de cultivo con suplemento de 10 % de suero fetal bovino con esferas generadas en un medio sin suero más factores de crecimiento. Resultados. Se determinó la expresión de proteínas de las células mesenquimales del estroma (CD29+, CD73+, CD90+, CD45-), de las basales horizontales (ICAM-1/CD54+, p63+, p75NGFr+), y de las del recubrimiento del nervio olfatorio (nestin+, GFAP+) en la misma población cultivada. La determinación de Oct 3/4, Sox-2 y Mash-1, así como de las neurotrofinas BDNF, NT3 y NT4, sugirió que las células del estroma son funcionales. La expresión de las proteínas de las células mesenquimales y los precursores olfatorios, disminuyó en las células de las mesenesferas inducidas por ausencia de suero en el medio de cultivo. Conclusión. Las células mesenquimales del estroma de la mucosa olfatoria presentan una tendencia dominante hacia la diferenciación neural.

Human olfactory mesenchymal stromal cells co-expressing horizontal basal and ensheathing cell proteins in culture / Las células mesenquimales del estroma olfatorio humano coexpresan proteínas de las células basales horizontales y de recubrimiento neural en cultivo

Introduction: The olfactory neuro-epithelium has an intrinsic capability of renewal during lifetime provided by the existence of globose and horizontal olfactory precursor cells. Additionally, mesenchymal stromal olfactory cells also support the homeostasis of the olfactory mucosa cell population. Under in vitro culture conditions with Dulbecco modified eagle/F12 medium supplemented with 10% fetal bovine serum, tissue biopsies from upper turbinate have generated an adherent population of cells expressing mainly mesenchymal stromal phenotypic markers. A closer examination of these cells has also found co-expression of olfactory precursors and ensheathing cell phenotypic markers. These results were suggestive of a unique property of olfactory mesenchymal stromal cells as potentially olfactory progenitor cells. Objective: To study whether the expression of these proteins in mesenchymal stromal cells is modulated upon neuronal differentiation. Materials and methods: We observed the phenotype of olfactory stromal cells under DMEM/F12 plus 10% fetal bovine serum in comparison to cells from spheres induced by serum-free medium plus growth factors inducers of neural progenitors. Results: The expression of mesenchymal stromal (CD29+, CD73+, CD90+, CD45-), horizontal basal (ICAM-1/CD54+, p63+, p75NGFr+), and ensheathing progenitor cell (nestin+, GFAP+) proteins was determined in the cultured population by flow cytometry. The determination of Oct 3/4, Sox-2, and Mash-1 transcription factors, as well as the neurotrophins BDNF, NT3, and NT4 by RT-PCR in cells, was indicative of functional heterogeneity of the olfactory mucosa tissue sample. Conclusions: Mesenchymal and olfactory precursor proteins were downregulated by serum-free medium and promoted differentiation of mesenchymal stromal cells into neurons and astroglial cells.

Introducción. El recambio celular del neuroepitelio olfatorio ocurre durante la vida del individuo gracias a precursores olfatorios. Además, las células mesenquimales del estroma también contribuyen a la homeostasis de la mucosa. Cuando un explante de una biopsia de mucosa se cultiva en un medio esencial mínimo, se genera una población predominante de células adherentes que expresan proteínas típicas de las células mesenquimales del estroma. La coexpresión de marcadores fenotípicos de precursores olfatorios y de células del recubrimiento del nervio olfatorio constituiría una propiedad única de las células mesenquimales del estroma. Objetivo. Determinar si la diferenciación celular de las células mesenquimales hacia fenotipos neurales modula la expresión de los marcadores mesenquimales característicos. Materiales y métodos. Se compararon las células aisladas de la mucosa olfatoria en un medio de cultivo con suplemento de 10 % de suero fetal bovino con esferas generadas en un medio sin suero más factores de crecimiento. Resultados. Se determinó la expresión de proteínas de las células mesenquimales del estroma (CD29+, CD73+, CD90+, CD45-), de las basales horizontales (ICAM-1/CD54+, p63+, p75NGFr+), y de las del recubrimiento del nervio olfatorio (nestin+, GFAP+) en la misma población cultivada. La determinación de Oct 3/4, Sox-2 y Mash-1, así como de las neurotrofinas BDNF, NT3 y NT4, sugirió que las células del estroma son funcionales. La expresión de las proteínas de las células mesenquimales y los precursores olfatorios, disminuyó en las células de las mesenesferas inducidas por ausencia de suero en el medio de cultivo. Conclusión. Las células mesenquimales del estroma de la mucosa olfatoria presentan una tendencia dominante hacia la diferenciación neural.

Adaptive neurogenesis in the cerebral cortex and contralateral subventricular zone induced by unilateral cortical devascularization: Possible modulation by dopamine neurotransmission.

Understanding endogenous neurogenesis and neuronal replacement to mature circuits is a topic of discussion as a therapeutic alternative under acute and chronic neurodegenerative disorders. Adaptive neurogenic response may result as a result of ischemia which could support long-term recovery of behavioral functions. Endogenous sources of neural progenitors may be stimulated by changes in blood flow or neuromodulation. Using a mouse model of unilateral cortical devascularization, we have observed reactive neurogenesis in the perilesional cortex and subventricular zone neurogenic niche. C57BL/6L 4 weeks old male mice were craneotomized at 1 mm caudal from frontal suture and 1 mm lateral from midline to generate a window of 3 mm side. Brain injury was produced by removal of the meninges and superficial vasculature of dorsal parietal cortex. BrdU agent (50 mg/kg, ip) was injected to lesioned and sham animals, during days 0 and 1 after surgery. Sagittal sections were analyzed at 1, 4, 7, and 10 days post-injury. A time-dependent increase in BrdU+ cells in the perilesional parietal cortex was accompanied by augmented BrdU+ cells in the sub ventricular and rostral migratory stream of ipsilateral and contralateral hemispheres. Neural progenitors and neuroblasts proliferated in the lesioned and non-lesioned subventricular zone and rostral migratory stream on day 4 after injury. Augmented contralateral neurogenesis was associated with an increase in vesicular monoamine transporter 2 protein in the striosomal sub ventricular neurogenic niche of non-lesioned hemisphere.