Mesenchymal stem cells and neural crest stem cells from adult bone marrow: characterization of their surprising similarities and differences.

in Cellular and Molecular Life Sciences : CMLS (2012), 69(15), 2593-2608

The generation of neuronal cells from stem cells obtained from adult bone marrow is of significant clinical interest in order to design new cell therapy protocols for several neurological disorders. The ... [more ▼]

The generation of neuronal cells from stem cells obtained from adult bone marrow is of significant clinical interest in order to design new cell therapy protocols for several neurological disorders. The recent identification in adult bone marrow of stem cells derived from the neural crest stem cells (NCSC) might explain the neuronal phenotypic plasticity shown by bone marrow cells. However, little information is available about the nature of these cells compared to mesenchymal stem cells (MSC), including their similarities and differences. In this paper, using transcriptomic as well as proteomic technologies, we compared NCSC to MSC and stromal nestin-positive cells, all of them isolated from adult bone marrow. We demonstrated that the nestin-positive cell population, which was the first to be described as able to differentiate into functional neurons, was a mixed population of NCSC and MSC. More interestingly, we demonstrated that MSC shared with NCSC the same ability to truly differentiate into Tuj1-positive cells when co-cultivated with paraformaldehyde-fixed cerebellar granule neurons. Altogether, those results suggest that both NCSC and MSC can be considered as important tools for cellular therapies in order to replace neurons in various neurological diseases. [less ▲]

Characterization of a SK-medium after-hyperpolarization in dorsal raphe neurons

Poster (2009, March 07)

NMDA-induced striatal brain damage and time-dependence reliability of thionin staining in rats

in Journal of Neuroscience Methods (2008), 168

Excitotoxic neuronal death induced by intracerebral injection of NMDA is a widely used model for investigating the potentially neuroprotective action of pharmacological agents against brain insults ... [more ▼]

Excitotoxic neuronal death induced by intracerebral injection of NMDA is a widely used model for investigating the potentially neuroprotective action of pharmacological agents against brain insults involving excitotoxic processes. Surprisingly, the time-course of NMDA-induced brain damage yet has not been investigated in the rat. Answering this question clearly needs to be assessed, given that the validity of preclinical neuroprotection studies requires to be insured that brain damage has reached a plateau that corresponds to the maximal extension of neuronal death at the time the brain is removed for histological analysis. Here, we investigated the time-course of neuronal death and the time-dependence validity of thionin coloration in rats that were given an intrastriatal injection of NMDA of 50 nmol or 70 nmol. Our results show that, whatever the dose used, NMDA-induced brain damage reaches its maximal value 24-48 h after the insult. They further indicate that the volume values of brain damage as estimated by thionin coloration constitute reliable data when the brain is removed up to 48 h after injection of NMDA. However, if the brain is removed more than 48 h after the excitotoxic insult onset, there is no alternative of using other techniques, such as immunochemical or neuroimaging techniques. [less ▲]

Propriétés pharmacologiques des récepteurs ionotropes au GABA du système nerveux central de la blatte Periplaneta americana

Poster (2002)

Ca2+/calmodulin dependent protein kinase regulates GABA activated Cl- current in cockroach dorsal unpaired median neurons

in Journal of Neurophysiology (2002), 87

We studied gamma-aminobutyric acid (GABA)-mediated currents in short-term cultured dorsal unpaired median (DUM) neurons of cockroach Periplaneta americana using the whole cell patch-clamp technique in ... [more ▼]

We studied gamma-aminobutyric acid (GABA)-mediated currents in short-term cultured dorsal unpaired median (DUM) neurons of cockroach Periplaneta americana using the whole cell patch-clamp technique in symmetrical chloride solutions. All DUM neurons voltage-clamped at -50 mV displayed inward currents (I(GABA)) when 10(-4) M of GABA was applied by pneumatic pressure-ejection pulses. The semi-logarithmic curve of I(GABA) amplitude versus the ejection time yielded a Hill coefficient of 4.0. I(GABA) was chloride (Cl-) because the reversal potential given by the current-voltage (I-V) curve varied according to the value predicted by the Nernst equation for Cl- dependence. In addition, I(GABA) was almost completely blocked by bath application of the chloride channel blockers picrotoxin (PTX) or 3,3-bis(trifluoromethyl)bicyclo-[2,2,1]heptane-2,2-diacarbonitrile (BIDN). The I-V curve for I(GABA) displayed a unexpected biphasic aspect and was best fitted by two linear regressions giving two slope conductances of 35.6 +/- 2.1 and 80.9 +/- 4.1 nS for potentials ranging from 0 to -30 and -30 to -70 mV, respectively. At -50 mV, the current amplitude was decreased by cadmium chloride (CdCl2, 10(-3) M) and calcium-free solution. The semi-logarithmic curve for CdCl2-resistant I(GABA) gave a Hill coefficient of 2.4. Hyperpolarizing voltage step from -50 to -80 mV was known to increase calcium influx through calcium-resting channels. According to this protocol, a significant increase of I(GABA) amplitude was observed. However, this effect was never obtained when the same protocol was applied on cell body pretreated with CdCl2. When the calmodulin blocker N-(6-aminohexyl)-5-chloro-1-naphtalene-sulfonamide or the calcium-calmodulin-dependent protein kinase blocker 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62) was added in the pipette solution, I(GABA) amplitude was decreased. Pressure ejection application of the cis-4-aminocrotonic acid (CACA) on DUM neuron cell body held at -50 mV, evoked a Cl- inward current which was insensitive to CdCl2. The Hill plot yielded a Hill coefficient of 2.3, and the I-V curve was always linear in the negative potential range with a slope conductance of 32.4 +/- 1.1 nS. These results, similar to those obtained with GABA in the presence of CdCl2 and KN-62, indicated that CACA activated one subtype of GABA receptor. Our study demonstrated that at least two distinct subtypes of Cl--dependent GABA receptors were expressed in DUM neurons, one of which is regulated by an intracellular Ca2+-dependent mechanism via a calcium-dependent protein kinase. The consequences of the modulatory action of Ca2+ in GABA receptors function and their sensitivity to insecticide are discussed. [less ▲]

Use of multiple electrophysiological techniques to get insigh into the mode of action of an insecticide, fipronil

in Veterinary and Human Toxicology (2001), 43(4), 238

Subcellular compartmentalization of activation and desensitization of responses mediated by NK2 neurokinin receptors

in Journal of Biological Chemistry (1999), 274

A functional fluorescent neurokinin NK2 receptor was constructed by joining enhanced green fluorescent protein to the amino-terminal end of the rat NK2 receptor and was expressed in human embryonic kidney ... [more ▼]

A functional fluorescent neurokinin NK2 receptor was constructed by joining enhanced green fluorescent protein to the amino-terminal end of the rat NK2 receptor and was expressed in human embryonic kidney cells. On cell suspensions, the binding of fluorescent Bodipy-labeled neurokinin A results in a saturatable and reversible decrease of NK2 receptor fluorescence via fluorescence resonance energy transfer. This can be quantified for nM to mM agonist concentrations and monitored in parallel with intracellular calcium responses. On single cells, receptor site occupancy and local agonist concentration can be determined in real time from the decrease in receptor fluorescence. Simultaneous measurement of intracellular calcium responses and agonist binding reveals that partial receptor site occupancy is sufficient to desensitize cellular response to a second agonist application to the same membrane area. Subsequent stimulation of a distal membrane area leads to a second response to agonist, provided that it had not been exposed to agonist during the first application. Together with persistent translocation of fluorescent protein kinase C to the membrane area exposed to agonist, the present data support that not only homologous desensitization but also heterologous desensitization of NK2 receptors is compartmentalized to discrete membrane domains. [less ▲]