Biology subjects

Di Maio, R.

Publications and source records attributed to Di Maio, R..

3 recordsLinked to original sources

bioRxiv2024

15-Lipoxygenase-Mediated Lipid Peroxidation Regulates LRRK2 Kinase Activity

Mutations in leucine-rich repeat kinase 2 (LRRK2) that increase its kinase activity are strongly linked to genetic forms of Parkinsons disease (PD). However, the regulation of endogenous wild-type (WT) LRRK2 kinase activity remains poorly understood, despite its frequent elevation in idiopathic PD (iPD) patients. Various stressors such as mitochondrial dysfunction, lysosomal dyshomeostasis, or vesicle trafficking deficits can activate WT LRRK2 kinase, but the specific molecular mechanisms are not fully understood. We found that the production of 4-hydroxynonenal (4-HNE), a lipid hydroperoxidation end-product, is a common biochemical response to these diverse stimuli. 4-HNE forms post-translational adducts with Cys2024 and Cys2025 in the kinase activation loop of WT LRRK2, significantly increasing its kinase activity. Additionally, we discovered that the 4-HNE responsible for regulating LRRK2 is generated by the action of 15-lipoxygenase (15-LO), making 15-LO an upstream regulator of the pathogenic hyperactivation of LRRK2 kinase activity. Pharmacological inhibition or genetic ablation of 15-LO prevents 4-HNE post-translational modification of LRRK2 kinase and its subsequent pathogenic hyperactivation. Therefore, 15-LO inhibitors, or methods to lower 4-HNE levels, or the targeting of Cys2024/2025 could provide new therapeutic strategies to modulate LRRK2 kinase activity and treat PD.

neuroscience↗

bioRxiv2021

Neuronal NADPH oxidase in Parkinson disease pathogenesis

Mitochondrial dysfunction and oxidative stress are strongly implicated in the pathogenesis of Parkinsons disease (PD) and there is evidence that mitochondrially-generated superoxide can activate NADPH oxidase 2 (NOX2), which is a major enzymatic generator of superoxide. Although NOX2 has been examined in the context of PD, previous studies have focused on microglial function; the role of neuronal NOX2 in PD pathogenesis remains to be defined. Here we devised and validated a proximity ligation assay for NOX2 activity and demonstrated that in human PD and 2 models thereof, neuronal NOX2 is highly active in substantia nigra dopamine neurons. Further, NOX2 activity is responsible for accumulation, post-translational modification and oligomerization of -synuclein as well as activation of leucine-rich repeat kinase 2 (LRRK2). Administration of a brain-penetrant, specific NOX2 inhibitor prevented NOX2 activation and its downstream effects in vivo in a rat model of PD. We conclude that neuronal NOX2 is a major contributor to oxidative stress in PD, to -synuclein pathology and to LRRK2 activation in idiopathic PD. In this context, NOX2 inhibitors hold potential as a disease-modifying therapy in PD. SummaryIn dopamine neuron, NADPH oxidase isoform 2 amplifies the oxidative stress-related pathogenic cascade in Parkinsons disease

neuroscience↗

bioRxiv2020

Disulfide bridge formation prevents CaMKII/Calmodulin interaction in Parkinson's disease

There is increasing evidence for disordered Ca2+ signaling in dopamine neurons in Parkinsons disease (PD), and this likely involves altered Ca2+/calmodulin-dependent protein kinase II (CaMKII) function. Previous work suggests that oxidative stress - a major feature in PD pathogenesis - affects regulatory methionine residues that sustain CaMKII activity in a Ca2+/CaM-independent manner. Here, applying computational modeling, we predicted formation of a defined disulfide bridge close to the CaMKII docking site for Ca2+/CaM binding. In vitro and in vivo investigations using PD models revealed formation of a disulfide bridge and loss of the CaMKII-calmodulin interaction. Mutagenesis of the relevant cysteine residues abrogated disulfide bridge formation and recovered the CaMKII-calmodulin interaction. Importantly, dopamine neurons from post-mortem PD brain specimens also lost this regulatory protein-protein interaction, providing relevance in the human disease. This study provides novel insights into oxidative CaMKII-CaM dysfunction, which may contribute to the pathophysiology of PD.

neuroscience↗