Production and evaluation of biosynthesized cellulose tubes as promising nerve guides for spinal cord injury treatment.

Spinal cord injury (SCI) is a central nervous disorder that can result in permanent motor and sensory damage due to a severed communication pathway. Although there is currently no effective treatment, nerve guide tubes have been used to bridge the injured stumps and act as drug delivery systems. In this study, biosynthesized cellulose (BC) nerve guides were prepared, and nerve growth factor (NGF)-a model growth factor-was incorporated into the tubular nerve guide in order to obtain a nerve guide/drug delivery system to assist the regeneration. To achieve this, Gluconacetobacter hansenii was cultivated in a special bioreactor to produce biosynthesized cellulose tubes (BCTs) in situ, and the physical and mechanical properties of the BCTs obtained from different cultivation time points were evaluated. Our results showed that the properties of the BCTs were comparable to those of the native human neural tissues, and that the NGF released from the BCTs was bioactive for at least 7 days as evaluated by PC12 cell cultures in vitro. In summary, this study evaluated the use of BCT as a drug releasing nerve guide, and our results showed that the BCT is an attractive strategy to enhance nerve regeneration after the SCI.

Rifampicin protects PC12 cells against MPP+-induced apoptosis and inhibits the expression of an alpha-Synuclein multimer.

The potential cytoprotective effects of the anti-leprosy antibiotic rifampicin were investigated in rat pheochromocytoma (PC12) cells prior to intoxication with 1-Methyl-4-phenyl pyridinium (MPP(+)). MPP(+) induced both apoptotic and necrotic cell death, and increased the expression of a 57 kDa species of alpha-Synuclein. This species of alpha-Synuclein is larger than the monomer, and is therefore an oligomer or an aggregated form of the protein. Rifampicin significantly increased survival of these catecholaminergic cells in a concentration-dependent manner. The expression of the higher molecular mass alpha-Synuclein was increased by MPP(+) exposure, and its expression was inversely related to cell survival in the rifampicin-treated cells. Importantly, rifampicin suppressed apoptosis almost completely, without shifting the death cascade to necrosis, which is a problem that has been reported with caspase inhibitors of apoptosis (Hartmann, A., Troadec, J.D., Hunot, S., Kikly, K., Faucheux, B.A., Mouatt-Prigent, A., Ruberg, M. Agid, Y., Hirsch, E.C., 2001. Caspase-8 is an effector in apoptotic death of dopaminergic neurons in Parkinson's disease, but pathway inhibition results in neuronal necrosis. J. Neurosci. 21, 2247-2255). These results suggest that rifampicin improves survival of catecholamine- and alpha-Synuclein-containing cells, which degenerate in Parkinson's disease (PD), and thus may be therapeutic in this disease.

Cyclosporine A treatment of leprosy patients with chronic neuritis is associated with pain control and reduction in antibodies against nerve growth factor.

OBJECTIVES: Chronic neuritis (CN) is still a major problem in leprosy and is difficult to manage in patients who do not respond well to prednisone. In this study we (i) evaluate the efficacy of cyclosporine A (CyA) in controlling CN patients, and (ii) analyse the presence of anti-NGF antibodies in the sera of leprosy patients, and their behaviour during CyA treatment. DESIGN: This was an open, prospective, non-comparative study. Sixty-seven leprosy patients in three different institutions in Pará, Brazil were studied from January, 2001 to January, 2004. Of these, 47 had no CN and 20 were leprosy patients suffering from CN and taking at least 40 mg/day prednisone to control nerve impairment and pain. Patients received 12 months reducing course CyA starting at 5 mg/kg per day. The outcome measure was sensory impairment, assessed using Semmes-Weinstein monofilament examination (SWME), muscular force and spontaneous or palpation-related pain. RESULTS: Antibodies against NGF were detected in the sera of leprosy patients, which may explain the depletion of NGF in leprosy contributing to neuritis, inflammation and loss of cutaneous nociception. The levels of these antibodies in CN patients were slightly lower than in patients with no CN. However, anti-NGF titres in CN patients treated with CyA were lowered to levels similar to those in the normal subjects. There was also improvement in sensory impairment, muscular force and pain. CONCLUSIONS: These data suggest that anti-NGF antibodies are present in the sera of leprosy patients and may influence the outcome of neuritis, and that CyA might be a useful drug in controlling nerve impairment and pain in leprosy patients.

Rifampicin inhibits the toxicity of pre-aggregated amyloid peptides by binding to peptide fibrils and preventing amyloid-cell interaction.

Rifampicin and its analogues, p-benzoquinone and hydroquinone, inhibited the toxicity of preformed aggregates of human islet amyloid polypeptide, amylin, to rat pheochromocytoma PC12 cells, when preincubated with the aggregated peptide before addition to cell cultures. Immunofluorescence microscopy showed that they prevented the adhesion of amylin aggregates to the cell surface, and this effect was induced probably by their binding to peptide fibrils during preincubation. Other quinone derivatives, i.e., p-methoxyphenol, AA-861 and idebenone, failed to inhibit the toxicity and cell-surface adhesion of amylin aggregates. Rifampicin analogues also inhibited the toxicity of pre-aggregated amyloid beta1-42 peptides, suggesting a common toxic mechanism of different amyloid peptides and their therapeutic potential for several amyloidoses.

Rifampicin prevents the aggregation and neurotoxicity of amyloid beta protein in vitro.

The aggregation and cerebral deposition of amyloid beta protein (A beta), which is a major component of senile plaques in Alzheimer's disease (AD) brains, is believed to be involved in the pathogenesis of AD. Inhibition of A beta aggregation would seem to be a promising strategy for the treatment of AD. Here, we show that rifampicin, which is an antibiotic widely used in the treatment of tuberculosis and leprosy, inhibited the aggregation and fibril formation of synthetic A beta 1-40 peptide in a dose-dependent manner at reasonable concentrations. Furthermore, rifampicin was found to prevent A beta 1-40-induced neurotoxicity on rat pheochromocytoma PC12 cells. Rifampicin may have therapeutic potential as an agent for inhibiting the initial step of amyloid formation in AD.

Both the basal and inducible transcription of the tyrosine hydroxylase gene are dependent upon a cAMP response element.

The cAMP response element (CRE) mediates cAMP responsiveness in many eukaryotic genes (Roesler, W. J., Vandenbark, G. R., and Hansen, R. W. (1988) J. Biol. Chem. 263, 9063-9066). The tyrosine hydroxylase gene (TH) contains a single copy of a consensus CRE at -45 to -38 base pair (bp) upstream of the transcription initiation site. Deletional and mutational analyses of the upstream 2400-base pair region of the rat TH gene using transient transfection assay demonstrated that the CRE was essential for both cAMP-mediated induction and basal transcription of the TH gene. Another domain between -365 and -151 bp, containing the AP1 site, contributed to transcription to a smaller degree. Thus, the CRE appears to play an important dual role as a basal promoter element and an inducible enhancer for TH transcription. Interactions between the DNA binding factors in nuclear extract and CRE-containing oligonucleotides were investigated by gel retardation and competition assays. Oligonucleotides corresponding to the CRE regions of the TH or somatostatin gene gave rise to a pair of distinct protein-DNA complexes with identical mobilities in the gel retardation assay, suggesting that similar nuclear factor(s) might bind to the CREs of the TH and somatostatin genes. This study emphasizes a fundamental role of the CRE in transcriptional activation of the TH gene in catecholaminergic cells.