Phosphodiesterase Inhibitors as a Therapeutic Approach to Neuroprotection and Repair

Targeting the 26S Proteasome To Protect Against Proteotoxic Diseases

Aggregates of misfolded proteins can compromise the function of the 26S proteasome complex, leaving neurons susceptible to accelerated and impaired protein homeostasis, thereby contributing to the pathogenesis of neurodegeneration. Strategies aimed at enhancing the function of the 26S proteasome via phosphorylation of key subunit epitopes have been effective in reducing protein aggregates in mouse models of disease. We discuss how phosphodiesterase (PDE) inhibitors and G protein-coupled receptor (GPCR)-targeted drugs might be considered as candidate therapeutics, acting on second messenger signal transduction. The range of candidates might address the need for region-, cell-, or even cellular compartment-specific modulation. Given the array of clinical and experimental drugs targeting cAMP/cGMP signaling, we propose that proteasome activators targeting secondary messengers might be exploited as novel agents for the treatment or prevention of some neurodegenerative diseases.

Iron prevents demyelination of frog sciatic nerves

Metal ions are of particular importance in nervous system function, notably iron. However, very little has been done to investigate its physiological role in frog peripheral nervous system. The present research aim to evaluate i) the time-effect of sciatic nerve ligation and/or ii) iron sulphate (1.50mg/kg, in lymphatic sac) on frog myelin sheaths. Histological sections following ligation shows degeneration of some fibres with axonal and myelin breakdown associated to a decrease of Schwann cells number following 2h (45.00±0.30, p<0.0001), 24h (28.00±0.020, p<0.0001). Interestingly, iron administration reduces the degeneration of myelin sheaths classically observed in frog ligated sciatic nerve associated with an increase of Schwann cells number (139.00±0.50, p<0.0001). Thus, iron could prevent degeneration or promote regeneration induced by ligation in frog sciatic nerve.

A comprehensive review on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases

Phosphodiesterases are a group of enzymes that hydrolyze cyclic nucleotides, which assume a key role in directing intracellular levels of the second messengers' cAMP and cGMP, and consequently cell function. The disclosure of 11 isoenzyme families and our expanded knowledge of their functions at the cell and molecular level stimulate the improvement of isoenzyme selective inhibitors for the treatment of various diseases, particularly cardiovascular diseases. Hence, future and new mechanistic investigations and carefully designed clinical trials could help reap additional benefits of natural/synthetic PDE inhibitors for cardiovascular disease in patients. This review has concentrated on the potential therapeutic benefits of phosphodiesterase inhibitors on cardiovascular diseases.