HMOX1 and Parkinson disease: However, it is important to report that opposite results have been recently published, proving that HO-1 up-regulation in astrocytic compartment is protective against neurodegeneration, as shown by exposure to the HO-1 inducer CoPPIX which protects astrocytes from β-amyloid toxicity [122] and that specific HO-1 induction in astrocytes may protect dopaminergic neurons preventing PD in MPTP-treated mice [123].