Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a component of the ubiquitin system, which has a fundamental role in regulating various biological activities. However, the functional role of the ubiquitin system in neurogenesis is not known. Here we show that UCH-L1 regulates the morphology of neural progenitor cells (NPCs) and mediates neurogenesis. UCH-L1 was expressed in cultured NPCs as well as in embryonic brain. Its expression pattern in the ventricular zone (VZ) changed between embryonic day (E) 14 and E16, which corresponds to the transition from neurogenesis to gliogenesis. At E14, UCH-L1 was highly expressed in the ventricular zone, where neurogenesis actively occurs; whereas its expression was prominent in the cortical plate at E16. UCH-L1 was very weakly detected in the VZ at E16, which corresponds to the start of gliogenesis. In cultured proliferating NPCs, UCH-L1 was co-expressed with nestin, a marker of undifferentiated cells. In differentiating cells, UCH-L1 was highly co-expressed with the early neuronal marker TuJ1. Furthermore, when UCH-L1 was induced in nestin-positive progenitor cells, the number and length of cellular processes of the progenitors decreased, suggesting that the progenitor cells were differentiating. In addition, NPCs derived from gad (UCH-L1-deficient) mice had longer processes compared with controls. The ability of UCH-L1 to regulate the morphology of nestin-positive progenitors was dependent on its binding affinity for ubiquitin but not on hydrolase activity; this result was also confirmed using gad-mouse-derived NPCs. These results suggest that UCH-L1 spatially mediates and enhances neurogenesis in the embryonic brain by regulating progenitor cell morphology.
"Secondly, UCH-L1 has been shown to have a dimerization dependent ubiquitin–ubiquitin ligase activity . Recent publications have demonstrated that some biological effects of UCH-L1 are based on its ability to bind to and thus stabilize mono-ubiquitin . Little is known regarding UCH-L1 specific substrates or biological activity in vivo. "
[Show abstract][Hide abstract] ABSTRACT: Podocytes are terminally differentiated cells of the glomerular filtration barrier that react with hypertrophy in the course of injury such as in membranous nephropathy (MGN). The neuronal deubiquitinase ubiquitin C-terminal hydrolase L1 (UCH-L1) is expressed and activated in podocytes of human and rodent MGN. UCH-L1 regulates the mono-ubiquitin pool and induces accumulation of poly-ubiquitinated proteins in affected podocytes. Here, we investigated the role of UCH-L1 in podocyte hypertrophy and in the homeostasis of the hypertrophy associated "model protein" p27Kip1. A better understanding of the basic mechanisms leading to podocyte hypertrophy is crucial for the development of specific therapies in MGN.
In human and rat MGN, hypertrophic podocytes exhibited a simultaneous up-regulation of UCH-L1 and of cytoplasmic p27Kip1 content. Functionally, inhibition of UCH-L1 activity and knockdown or inhibition of UCH-L1 attenuated podocyte hypertrophy by decreasing the total protein content in isolated glomeruli and in cultured podocytes. In contrast, UCH-L1 levels and activity increased podocyte hypertrophy and total protein content in culture, specifically of cytoplasmic p27Kip1. UCH-L1 enhanced cytoplasmic p27Kip1 levels by nuclear export and decreased poly-ubiquitination and proteasomal degradation of p27Kip1. In parallel, UCH-L1 increased podocyte turnover, migration and cytoskeletal rearrangement, which are associated with known oncogenic functions of cytoplasmic p27Kip1 in cancer.
We propose that UCH-L1 induces podocyte hypertrophy in MGN by increasing the total protein content through altered degradation and accumulation of proteins such as p27Kip1 in the cytoplasm of podocytes. Modification of both UCH-L1 activity and levels could be a new therapeutic avenue to podocyte hypertrophy in MGN.
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease 07/2014; 1842(7). DOI:10.1016/j.bbadis.2014.02.011 · 4.88 Impact Factor
"PGP9.5 protein, which derives from the gene Uchl1, is an ubiquitin hydrolase that is found both in the cell soma as well as in axonal processes (Thompson et al., 1983; Young et al., 2003; Corpening et al., 2011). While PGP9.5 is often used as generic marker to identify mature neurons, it also labels cells in early phases of neuronal differentiation in both the central and peripheral nervous systems (Sidebotham et al., 2001; Sakurai et al., 2006; D’Autreaux et al., 2007). The IHC distribution of NF and PGP9.5 revealed discrete clusters of developing neurons in the forming sympathetic chain at the dorsal mid-line of the UGT (Figures 1A,B). "
[Show abstract][Hide abstract] ABSTRACT: Relative positions of neurons within mature murine pelvic ganglia based on expression of neurotransmitters have been described. However the spatial organization of developing innervation in the murine urogenital tract (UGT) and the gene networks that regulate specification and maturation of neurons within the pelvic ganglia of the lower urinary tract (LUT) are unknown. We used whole-mount immunohistochemistry and histochemical stains to localize neural elements in 15.5 days post coitus (dpc) fetal mice. To identify potential regulatory factors expressed in pelvic ganglia, we surveyed expression patterns for known or probable transcription factors (TF) annotated in the mouse genome by screening a whole-mount in situ hybridization library of fetal UGTs. Of the 155 genes detected in pelvic ganglia, 88 encode TFs based on the presence of predicted DNA-binding domains. Neural crest (NC)-derived progenitors within the LUT were labeled by Sox10, a well-known regulator of NC development. Genes identified were categorized based on patterns of restricted expression in pelvic ganglia, pelvic ganglia and urethral epithelium, or pelvic ganglia and urethral mesenchyme. Gene expression patterns and the distribution of Sox10+, Phox2b+, Hu+, and PGP9.5+ cells within developing ganglia suggest previously unrecognized regional segregation of Sox10+ progenitors and differentiating neurons in early development of pelvic ganglia. Reverse transcription-PCR of pelvic ganglia RNA from fetal and post-natal stages demonstrated that multiple TFs maintain post-natal expression, although Pax3 is extinguished before weaning. Our analysis identifies multiple potential regulatory genes including TFs that may participate in segregation of discrete lineages within pelvic ganglia. The genes identified here are attractive candidate disease genes that may now be further investigated for their roles in malformation syndromes or in LUT dysfunction.
Frontiers in Neuroscience 09/2012; 6:130. DOI:10.3389/fnins.2012.00130 · 3.66 Impact Factor
"Secondly, the mutation in the gracile axonal dystrophy (gad) mouse was mapped to a deletion in the Uchl1 gene , and subsequent work on this model revealed that UCHL1 regulates the morphology and differentiation of neural progenitor cells . Thus the Uchl1 (gad) mouse provides a useful model for further study. "
[Show abstract][Hide abstract] ABSTRACT: Deubiquitylating enzymes (DUBs) can hydrolyze a peptide, amide, ester or thiolester bond at the C-terminus of UBIQ (ubiquitin), including the post-translationally formed branched peptide bonds in mono- or multi-ubiquitylated conjugates. DUBs thus have the potential to regulate any UBIQ-mediated cellular process, the two best characterized being proteolysis and protein trafficking. Mammals contain some 80–90 DUBs in five different subfamilies, only a handful of which have been characterized with respect to the proteins that they interact with and deubiquitylate. Several other DUBs have been implicated in various disease processes in which they are changed by mutation, have altered expression levels, and/or form part of regulatory complexes. Specific examples of DUB involvement in various diseases are presented. While no specific drugs targeting DUBs have yet been described, sufficient functional and structural information has accumulated in some cases to allow their rapid development.
Republished from Current BioData's Targeted Proteins database (TPdb; ).
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