Isabel Mayo

Sensory Vagal Nature and Anatomical Access Paths to Esophagus Laminar Nerve Endings in Myenteric Ganglia. Determination by Surgical Degeneration Methods

The dependence, access paths and functional significance of the intraganglionic laminar nerve endings (IGLEs) in the esophageal wall of the cat are demonstrated. To this end Wallerian degeneration was induced on the vagus nerve by a number of surgical operations performed at the nodose ganglion level. The results show IGLEs to be sensorial receptors dependent on neuronal bodies situated in the nodose ganglion. The nerve fibers on which they depend to reach the esophageal wall gain access via the vagus and the superior laryngeal nerve.

α-Synuclein expression levels do not significantly affect proteasome function and expression in mice and stably transfected PC12 cell lines

α-Synuclein (α-syn) is a small protein of unknown function that is found aggregated in Lewy bodies, the histopathological hallmark of sporadic Parkinson disease and other synucleinopathies. Mutations in the α-syn gene and a triplication of its gene locus have been identified in early onset familial Parkinson disease. α-Syn turnover can be mediated by the proteasome pathway. A survey of published data may lead to the suggestion that overexpression of α-syn wild type, and/or their variants (A53T and A30P), may produce a decrease in proteasome activity and function, contributing to α-syn aggregation. To investigate the relationship between synuclein expression and proteasome function we have studied proteasome peptidase activities and proteasome subunit expression (α, β-constitutive, and inducible) in mice either lacking α-syn (knock-out mice) or transgenic for human α-syn A30P (under control of PrP promoter, at a time when no clear gliosis can be observed). Similar studies are presented in PC12 cells overexpressing enhanced yellow fluorescent protein fusion constructs of human wild type, A30P, and A53T α-syn. In these cell lines we have also analyzed the assembly of 20 S proteasome complex and the degradation rate of a well known substrate of the proteasome pathway, Iκbα. Overall the data obtained led us to the conclusion that α-synuclein expression levels by themselves have no significant effect on proteasome peptidase activity, subunit expression, and proteasome complex assembly and function. These results strengthen the suggestion that other mechanisms resulting in synuclein aggregation (not simply expression levels) may be the key to understand the possible effect of aggregated synuclein on proteasome function.

Antibodies against the COOH-terminal region of E. coli ClpP protease in patients with primary biliary cirrhosis

BACKGROUND/AIMS The presence of antibodies in sera from patients with autoimmune diseases is an important tool for diagnosis and for providing insights into the mechanisms leading to autoimmunity. The aim of this study was to characterize new reactive antigens in liver autoimmune diseases. METHODS Sera of patients with liver-related autoimmune (n=74) and non-liver-related autoimmune (n= 211) diseases, non-autoimmune liver diseases (n=18) and healthy controls (n=160) were evaluated for antibodies against E. coli ClpP protease (EClpP) and 20S proteasome by immunoblot analysis. RESULTS Antibodies against EClpP were detected in 15 of 50 patients with primary biliary cirrhosis, in only one of 100 patients with systemic lupus erythematosus, and in three healthy subjects (Chi-square 59.1, d.f. 2, p< 0.001). Antibodies to 20S proteasome were found in only 35 of 100 patients with systemic lupus erythematosus. All other sera from patients with autoimmune diseases, liver diseases other than primary biliary cirrhosis, and healthy controls were negative for both antigens. Both IgG and IgM classes of antibodies against EClpP were present in primary biliary cirrhosis patient sera with titers of 1/400-1/1000. By using recombinant techniques and peptide ELISA, the immunodominant EClpP epitope recognized by the sera from primary biliary cirrhosis patients was localized in the amino acid sequences 177-194 (QIERDTERDRFLSAPEAV) within the COOH-terminal of EClpP. Affinity-purification of these anti-EClpP antibodies and immunoabsorption experiments established that the antibodies are specific for the bacterial EClpP. CONCLUSIONS Bacterial ECIpP has been identified as a new antigen specifically reacting with sera from approximately one third of patients with primary biliary cirrhosis.

Proteasome dynamics during cell cycle in rat Schwann cells

The proteasome is responsible for most of the protein degradation that takes place in the cytoplasm and nucleus. Immunofluorescence and electron microscopy are used to study proteasome dynamics during the cell cycle in rat Schwann cells. During interphase, the proteasome is present in the nucleus and cytoplasm and shows no colocalization with cytoskeletal components. Some cytoplasmic proteasomes always localize in the centrosome both in interphase and in mitotic cells and only associate with microtubules during mitosis. The proteasome exits the nucleus during prophase. In anaphase, the proteasome becomes prominent in the region between the two sets of migrating chromosomes and in association with interzonal microtubules and stem bodies. In telophase, the proteasome begins to reenter the nucleus and is prominent in the midbody region until the end of cytokinesis. The proteasome does not colocalize with actin or vimentin during mitosis, except for colocalization with actin in the sheet‐like lamellipodia, which serve as substrate attachments for the cell during mitosis. During S phase, nuclear proteasomes colocalize with foci of BrdU incorporation, but this association changes with time: maximal at early S phase and declining as S phase progresses to the end. These results are discussed in relation to the biochemical pathways involved in cell cycle progression. GLIA 38:313–328, 2002.

New contribution on the oesophageal mucous innervation in certain monkeys (Cercopithecidae)

Spindle-shaped, barrel-like, or bush-like corpuscular neural structures situated in the mucous epithelium of the upper third of the oesophagus are described. These structures are not homogeneously distributed in this area. Some are very close to the pharyngooesophageal sphincter, spanning the thickness of the epithelium and communicating with the basal membrane by means of a thin pedicle and with the lumen by a small hilus or pore, their morphology being that of a taste bud. The others are situated deeper in the mucous epithelium of the upper third, communicating with the basal membrane only by means of either a thin pedicle or a thicker one, and separated from the lumen by a thick layer of epithelial cells. The bush-like apparatuses lie closely adjacent to the basal membrane of the epithelium.

Effects of surgical sympathectomy on laminar nerve endings in myenteric ganglia

Extirpation of the anterior regions of the sympathetic ganglionated chain (all cervical ganglia and the four subsequent thoracic ganglia) has been carried out in the cat. Histological study of the esophagus wall has shown intraganglionic laminar endings (IGLEs) to suffer an alteration which, in time, reverts to normality. Since it is not a Wallerian degeneration as such, we conclude, contrary to what has previously been assessed by some authors, that these nerve apparatuses are not dependent either on nerve cells located in sympathetic ganglia or on nerve fibers coursing through the sympathetic trunk. Speculations are made as to why IGLEs undergo a transitory alteration after experimental destruction of nerve structures to which they are not directly related.