Biology subjects

Bertoli, F.

Publications and source records attributed to Bertoli, F..

3 recordsLinked to original sources

bioRxiv2025

Engineering substantia nigra-like dopaminergic neurons in human midbrain organoids through WNT modulation and bioreactor culture

Human midbrain organoids (hMOs) derived from induced pluripotent stem cells provide a powerful system to model disorders involving dopamine (DA) dysfunction, including Parkinsons disease (PD) and neuropsychiatric conditions. However, current differentiation protocols still fall short in recapitulating early specification, substantia nigra pars compacta (SNpc)-like identity, and the functional maturation of vulnerable DA neurons. Here, we established a differentiation strategy that combines tri-phasic WNT modulation with dynamic bioreactor culture to generate hMOs enriched in SNpc-like DA neurons. This approach significantly increases the yield of TH/GIRK2 and TH/ALDH1A1 DA neurons and promotes enhanced synaptic maturation, robust electrophysiological activity, and elevated DA release. Single-cell transcriptomics revealed that this strategy drives the emergence of SOX6+/GIRK2+ SNpc-like neurons, accompanied by upregulation of synaptic, metabolic, and maturation programs, alongside reduced cell stress and apoptotic signaling. Importantly, hMOs demonstrated vulnerability upon exposure to -synuclein preformed fibrils, resulting in aggregate formation and DA neuron degeneration, supporting their use as a human model of PD-relevant pathology. Overall, this system provides a scalable and physiologically relevant approach to investigate molecular mechanisms underlying neurodegeneration and DA-related disorders.

neuroscience↗

bioRxiv2024

The mitochondrial unfolded protein response promotes senescence in human microglia by increasing S-adenosylmethionine availability for polyamine synthesis.

Mitochondria have evolved a specialized mitochondrial unfolded protein response (UPRmt) to maintain proteostasis and promote recovery under stress. Studies in simple organisms have shown that UPRmt activation in glial cells supports proteostasis through beneficial noncell-autonomous communication with neurons. However, the role of mitochondrial stress responses in the human brain remains unclear. To address this gap, we investigated the cell type-specific effects of mitochondrial proteotoxic stress using human induced pluripotent stem cell-derived neuronal and glial cultures, as well as brain organoids. We show that mitochondrial proteotoxic stress induces metabolic rewiring in human microglia, marked by depletion of S-adenosylmethionine and lipid remodeling, ultimately leading to a senescent phenotype. Using human neuronal-glial tricultures and microglia-containing brain organoids, we identified the specific contributions of microglia to brain senescence and mitochondrial stress-driven neurodegenerative processes. UPRmt activation disrupts microglial communication with neighboring cells, triggering inflammatory signaling and impairing proteostasis. Together, these findings reveal how impaired mitochondrial proteostasis alters intercellular networks and identify a critical role for the UPRmt in neurodegenerative disease pathogenesis.

neuroscience↗

bioRxiv2022

LRRK2-G2019S SYNERGIZES WITH AGEING AND LOW-GRADE INFLAMMATION TO PROMOTE GUT AND PERIPHERAL IMMUNE CELL ACTIVATION THAT PRECEDE NIGROSTRIATAL DEGENERATION

BackgroundMutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most frequent cause of familial Parkinsons disease (PD). The incomplete penetrance of LRRK2 mutations suggest that additional hits are required for disease onset. We hypothesized that chronic low-grade inflammation interacts with LRRK2 G2019S, the most frequent PD-associated mutation, to activate peripheral and central immune reactions and drive age-dependent neurodegeneration. Methods and ResultsWe exposed wild-type and LRRK2 G2019S mice to a low chronic dose of lipopolysaccharide, and we performed a longitudinal analysis of central and peripheral immune reactions and neurodegeneration. Low-dose inflammation triggered nigrostriatal degeneration, macrophage/monocyte brain infiltration, and astro-/microgliosis. LRRK2 G2019S mice showed an early dysregulation of peripheral cytokines, increased CD4+ T-cell infiltration and -synuclein aggregation in the colon. Interestingly, peripheral immune activation and colonic -synuclein aggregation precede astro-/microgliosis and neurodegeneration. ConclusionsOur study suggests an early role of the peripheral immune system and the gut in LRRK2 PD and provides a novel model to study early therapeutic immune targets and biomarkers.

neuroscience↗