6 research outputs found
DOPAMINE D4 RECEPTOR EXPRESSION IN RAT KIDNEY. EVIDENCE FOR PRE-AND POSTJUNCTIONAL LOCALIZATION.
No full textIF.2.61
Cell Biology
Dopamine D4 Receptor Expression in Rat Kidney: Evidence for Pre- and Postjunctional Localization
No full textDopamine D4 receptors mediate inhibition of vasopressin-dependent sodium reabsorption by dopamine in collecting tubules. At present, the distribution of D4 receptors in other renal districts remains an open issue. The renal distribution of D4 receptor was assessed in normally innervated and denervated male Sprague-Dawley rats by quantitative immunohistochemistry using an anti-dopamine D4 receptor rabbit polyclonal antibody. D4 receptor protein immunoreactivity was observed perivascularly in the adventitia and the adventitia-media border. The density of perivascular dopamine D4 receptor was higher in afferent and efferent arterioles than in other segments of the renal vascular tree. Renal denervation abolished perivascular dopamine D4 receptor protein immunoreactivity. In renal tubules, the epithelium of collecting tubules showed the highest dopamine D4 receptor protein immunoreactivity, followed by the epithelium of proximal and distal tubules. No dopamine D4 receptor protein immunoreactivity was observed in the epithelium of the loop of Henle. Denervation did not change dopamine D4 receptor protein immunoreactivity in renal tubules. These results indicate that rat kidney expresses dopamine D4 receptors located both prejunctionally and nonprejunctionally in collecting, proximal, and distal tubules. This suggests that the dopamine D4 receptor may be involved in the control of neurotransmitter release and in renal hemodynamic and tubule functio
Mitochondrial activity is involved in the regulation of myoblast differenciation through myogenin expression and activity of myogenic factors
No full textBTG1: a triiodothyronine target involved in the myogenic influence of the hormone
No full textInternational audienc
Molecular mechanisms underlying Mash1 function in oligodendrogenesis
No full textMembers of the basic helix-loop-helix (bHLH) proneural family of proteins, including Mash1, are crucial transcription factors (TFs) in neurogenesis. More recently, a role for Mash1 in the specification of
oligodendrocyte precursor cells (OPCs) has been demonstrated. Here we investigate the role of Mash1 in lineage commitment of neural progenitors and
more specifically the mechanisms underlying Mash1 activity in oligodendroglial cell fate specification.
We use an in vitro cell culture system to perform Mash1 locational
analysis. Mouse OPCs were cultured as oligospheres that expressed Mash1, a proportion of which also coexpressed the early OPC marker platelet-derived growth factor receptor \alpha (PDGFR\alpha) and oligodendrocyte promoting TFs
including the bHLH TF Olig2 and the high mobility group (HMG) TF Sox9. We
use a chromatin immunoprecipitation (ChIP)-on-chip strategy and found that
Mash1 protein binds to proximal genomic regions of early OPC genes such as
Olig1 and Sox8, late oligodendrocyte genes including myelin oligodendrocyte
glycoprotein (Mog) and oligodendrocyte myelin glycoprotein (Omg), and other
genes of interest including Brevican (Bcan), Notch1 and Sulfatase1 (Sulf1).
Mash1 also bound distal genomic regions of Olig2 and Sox9 in oligosphere
cultures. To formulate a TF combinatorial code for the activation of these
putative enhancers, TF synergy were analysed with luciferase reporter assays.
Furthermore, to isolate genomic regions with activity in the oligodendroglial
lineage in vivo we used mouse transient transgenics. We hypothesise that Mash1 interacts with either neuronal- or oligodendroglial-specific cofactors, and that
these interactions modulate Mash1 activity. To address this question we performed Sox9 and Olig2 ChIP and found that some Mash1 bound elements
were also occupied by these TFs in oligosphere cultures.
In conclusion, using an in vitro cellular system and ChIP-on-chip technology to interrogate proximal promoter regions bound by Mash1, we can
begin to elucidate the molecular mechanisms of Mash1 function in oligodendroglial cell fate specification
The effect of in vitro culture on the stability, expansion and neuronal differentiation of human pluripotent cell lines
No full textPluripotent cells are defined by their ability to both self-renew and to differentiation into any cell type within the human body. As such, pluripotent cell lines are of great interest as starting material for drug screening and cell therapies for regenerative treatment of diseased tissues. Pluripotent cell lines were originally derived from germ cell tumors (embryonal carcinoma cells; EC), but have since been isolated and expanded from the inner cell mass of an early embryo (human embryonic stem cells; hESCs).
This project set out to investigate the relative ability of the pluripotent NTERA2 (EC) cell line and hESC lines: Shef3, HUES7 and RH5, to differentiate into neurons, using mechanical and enzymatic culture methods. Focus was placed on monitoring differentiation efficiency and function between the different lines.
The tumour origin, in addition to the poor reproducibility, low yield and reduced functionality of NTERA2 derived neurons, compared to primary neurons, makes their incorporation into regenerative therapies unlikely. As such, an enhanced neuronal differentiation protocol was developed for use in hESCs. Cell populations were monitored for relative changes in gene and protein expression at selected time points throughout differentiation using standard RT-PCR, Q-PCR and immuno fluorescence analysis. End stage neurons were screened for functionality using patch clamping and calcium imaging techniques. Monitoring of cellular behavior through differentiation was aided by the concurrent development of a portable microscope incubator stage in collaboration with Linkam scientific Ltd.
These data demonstrate a variation in the ability to generate neurons from pluripotent cell lines, and suggests a predetermined, preferential cell fate within each line, even at the level of pluripotency. This study also characterises in detail neuronal differentiation from pluripotent cells, adding to the understanding which is essential for translation into therapies for neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and Huntingdon’s disease
