Biology subjects

Arena, G.

Publications and source records attributed to Arena, G..

5 recordsLinked to original sources

bioRxiv2024

DJ-1 mediates regulation of metabolism and immune response in Parkinsons disease astrocytes and Glioblastoma cells

An inverse correlation for the expression of Parkinsons disease (PD)- and cancer-associated genes has been previously reported. Genes that are upregulated in cancer are frequently downregulated in PD and vice versa. PARK7, encoding DJ-1, was initially identified as an oncogene, but loss of DJ-1 causes early-onset PD. However, it remains elusive how differential DJ-1 levels contribute to opposite cell fates in cancer and PD. Here, we demonstrate specific effects of differential DJ-1 protein levels on the energy metabolism and cell growth in patient-derived cellular models of PD and glioblastoma (GBM) cell lines. Impaired energy metabolism was associated with an increased immune response upon IL-1{beta} stimulation and increased apoptosis and decreased cell growth in models of PD, whereas in GBM cells increased metabolic activity translated into a reduced immune response and increased cell growth. Furthermore, we found decreased glutathione (GSH) synthesis and therefore increased levels of reactive oxygen species (ROS) and oxidized glutathione (GSSG) in models of DJ-1 deficiency and decreased ROS levels in GBM cell lines. Thus, the mechanism by which DJ-1 modulates these phenotypes is the same in both diseases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/621212v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@4eccb4org.highwire.dtl.DTLVardef@161669corg.highwire.dtl.DTLVardef@197bfc3org.highwire.dtl.DTLVardef@1aecb36_HPS_FORMAT_FIGEXP M_FIG C_FIG DJ-1 levels modulate GSSG/GSH ratio and ROS levels, which results in divergent effects on cell growth and immune response in DJ-1-dependent glial pathologies in glioblastoma and PD. In models of PD, DJ-1 level dependent phenotypes can be rescued by antioxidant treatment that reduces the GSSG/GSH ratio and ROS levels.

neuroscience↗

bioRxiv2024

Out of the single-neuron straitjacket: neurons within assemblies change selectivity and their reconfiguration underlies dynamic coding

We investigated cell assemblies in the frontal cortex of macaques during two discrimination tasks. Focusing on the period of goal-action transformation, we extracted spikes fired during assembly activation from the full neural activity and showed that the contribution of a neuron to assembly coding, when it coordinates with other assembly neurons, differs from its coding in isolation. Neurons with their flexible participation to multiple assemblies contributed to the encoding of new information not encoded by the neurons alone. Even non-discriminative neurons acquired selectivity as part of the collective activity of the assemblies. Thus, neurons in their assemblies process distinct information for various purposes as a chess simul master, playing on multiple chessboards. The reconfiguration of the participation of the neurons into different assemblies in the goal-action transformation process translated into a dynamic form of coding, whereas minimal reconfiguration was associated with the static goal coding of the memory period.

neuroscience↗

bioRxiv2024

Insulin resistance compromises midbrain organoid neural activity and metabolic efficiency predisposing to Parkinsons disease pathology

Growing evidence indicates that Type 2 Diabetes (T2D) is associated with an increased risk of developing Parkinsons disease through shared disease mechanisms. Studies show that insulin resistance, which is the driving pathophysiological mechanism of T2D plays a major role in neurodegeneration by impairing neuronal functionality, metabolism, and survival. To investigate insulin resistance caused pathological changes in the human midbrain, which could predispose a healthy midbrain to PD development, we exposed iPSC-derived human midbrain organoids from healthy individuals to either high insulin concentrations, promoting insulin resistance, or to more physiological insulin concentrations restoring insulin signalling function. We combined experimental methods with metabolic modelling to identify the most insulin resistance-dependent pathogenic processes. We demonstrate that insulin resistance compromises organoid metabolic efficiency, leading to increased levels of oxidative stress. Additionally, insulin-resistant midbrain organoids showed decreased neural activity and reduced amount of dopaminergic neurons, highlighting insulin resistance as a significant target in PD prevention.

neuroscience↗

bioRxiv2023

Parkinson's disease-related Miro1 mutation induces mitochondrial dysfunction and loss of dopaminergic neurons in vitro and in vivo

The complex and heterogeneous nature of Parkinsons disease (PD) is still not fully understood, however, increasing evidence supports mitochondrial impairments as a major driver of neurodegeneration in PD. Recently, the regulator of mitochondrial homeostasis Miro1 has been linked genetically and pathophysiologically to PD. Using 2D and 3D patient-based induced pluripotent stem cells models, including an isogenic control, showed that the Miro1 p.R272Q mutation leads to mitochondrial impairments including increased oxidative stress, disrupted mitochondrial bioenergetics and altered metabolism. This was accompanied by increased -synuclein levels in 2D dopaminergic neurons and by a significant reduction of dopaminergic neurons within midbrain organoids. Knock-in mice expressing mutant p.R285Q Miro1 (orthologue of the human p.R272Q mutation) confirmed the PD-specific dopaminergic neuronal loss in the substantia nigra, accumulation of striatal phosphorylated -synuclein accompanied by behavioral alterations. These findings demonstrate that mutant Miro1 is sufficient to comprehensively model PD-relevant phenotypes in vitro and in vivo, reinforcing its pivotal role in PD pathogenesis.

neuroscience↗

bioRxiv2023

Mitochondrial CISD1 is a downstream target that mediates PINK1 and Parkin loss-of-function phenotypes

Parkinsons disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra of the midbrain. Familial cases of PD are often caused by mutations of PTEN-induced kinase 1 (PINK1) and the ubiquitin ligase Parkin, both pivotal in maintaining mitochondrial quality control. CISD1, a homodimeric mitochondrial iron-sulfur-binding protein, is a major target of Parkin-mediated ubiquitination. We here discovered a heightened propensity of CISD1 to form dimers in Pink1 mutant flies and in dopaminergic neurons from PINK1 mutation patients. The dimer consists of two monomers that are covalently linked by a disulfide bridge. In this conformation CISD1 cannot coordinate the iron-sulfur cofactor. Overexpressing Cisd, the Drosophila orthologue of CISD1, and a mutant Cisd incapable of binding the iron-sulfur cluster in Drosophila reduced climbing ability and lifespan. This was more pronounced with mutant Cisd and aggravated in Pink1 mutant flies. Complete loss of Cisd, in contrast, rescued all detrimental effects of Pink1 mutation on climbing ability, wing posture, dopamine levels, lifespan, and mitochondrial ultrastructure. Our results suggest that Cisd, probably iron-depleted Cisd, operates downstream of Pink1 shedding light on PD pathophysiology and implicating CISD1 as a potential therapeutic target.

neuroscience↗