Statins decrease expression of the proinflammatory neuropeptides calcitonin gene-related peptide and substance P in...

Area of Science:

• Neuroscience
• Pharmacology
• Inflammation Research

Background:

• Clinical observations suggest statins may treat neurogenic inflammation.
• The precise mechanisms underlying statins' therapeutic effects in neurogenic inflammation are not well understood.

Purpose of the Study:

• To investigate if statins directly reduce sensory neuron expression of proinflammatory neuropeptides, specifically calcitonin gene-related peptide (CGRP) and substance P.
• To elucidate the molecular mechanisms by which statins might attenuate neurogenic inflammation.

Main Methods:

• Quantified CGRP and substance P expression in rat dorsal root ganglia (DRG) and cultured sensory neurons using reverse transcriptase-polymerase chain reaction, radioimmunoassay, and immunocytochemistry.
• Administered statins systemically in vivo and in vitro, assessing effects on neuropeptide expression and bone morphogenetic protein (BMP)-induced signaling pathways.

Main Results:

• Systemic statin administration significantly reduced CGRP and substance P levels in DRG.
• In cultured neurons, statins blocked BMP-induced neuropeptide expression and decreased basal expression, independent of cell survival.
• Statin effects were reversed by mevalonate and cholesterol, linked to cholesterol depletion inhibiting Smad1 phosphorylation and nuclear translocation.

Conclusions:

• Statins exert a novel action by down-regulating proinflammatory neuropeptide expression in sensory ganglia.
• This effect is mediated through cholesterol depletion and reduced Smad1 activation.
• Statins show potential as a therapeutic strategy for attenuating neurogenic inflammation.