Biology subjects

Zanetti, L.

Publications and source records attributed to Zanetti, L..

4 recordsLinked to original sources

bioRxiv2026

Prion Protein Deficiency Results in Synaptic, Neural Network and Behavioral Alterations

The cellular form of the prion protein (PrPC) is known for its involvement in the pathogenesis of prion diseases. Recent research implicates the physiological isoform of PrP in neuronal development, excitability, and synaptic plasticity, as well as in other biological processes. However, its precise function in the development and function of neurons remains poorly understood. Here, we investigated its role during different developmental stages, both in vitro and in vivo, using different PrP knock-out (KO) mouse lines (Prnp-/-). Prion protein KO neurons cultured on microelectrode arrays (MEAs) displayed altered network dynamics compared to wild type cultures, comprising reduced burst frequency, and abnormal spike patterns, indicative of impaired maturation of the synaptic circuitry. These functional alterations were associated with a reduced expression of key presynaptic and postsynaptic proteins, including elements of the SNARE complex and regulators of excitation-inhibition balance. Similar molecular changes were also confirmed in a second Prnp-/- model, suggesting that PrPC is directly involved in these mechanisms regardless of genetic backgrounds. Alterations in neuronal networks were traceable into adulthood: in vivo recordings in adult Prnp-/- mice revealed increased neuronal responses to visual danger stimuli, which correlated with behaviorally increased fear responses to those stimuli. Together, our findings support a critical role for PrPC in the establishment and maintenance of functional neuronal networks, from early developmental stages in vitro to behaviorally mature relevant circuits in vivo, beyond genomic background. These results indicate that PrPC acts as a key regulator of synaptic development and function both in physiological and pathological conditions.

molecular biology↗

bioRxiv2025

Go/z-biased coupling profile of the dopamine D3 receptor

Dopamine receptors are G protein coupled receptors (GPCRs) that serve as key targets for FDA-approved drugs used to treat various neuropsychiatric disorders. Notably, [~]11% of all marketed GPCR-targeting drugs act on dopamine receptors. Five GPCRs mediate the effects of endogenous dopamine and compounds used to treat Parkinsons disease, schizophrenia, and other conditions. However, on-target side effects associated with these medications highlight the need to analyze dopamine receptor signaling to design safer, more effective therapeutics. We characterized the G protein coupling of dopamine D2-like receptors and observed the striking inability of D3R to engage with Gi proteins while effectively activating Go and Gz subtypes. Applying orthogonal cell-based assays that utilize wild-type G proteins both in parental and {Delta}Gi/o/z cells, we conclusively established that D3R does not activate Gi proteins. Further analysis of Gi2:GoA and D2R:D3R chimeras revealed that this selective inability is driven by molecular determinants located within the 5 helix of Gi and the intracellular loop 2 (ICL2) of D3R. Guided by cryo-EM structures, we modeled the interface between these regions to better understand the structural basis of this selectivity. Finally, we treated hippocampal neurons in acute brain slices with selective agonists for D2R and D3R and observed marked differences in their ability to regulate endogenous adenylyl cyclase to produce cAMP, highlighting the neurophysiological significance of our findings.

pharmacology and toxicology↗

bioRxiv2023

Dopamine neuron dysfunction and loss in the PrknR275W mouse model of Juvenile Parkinsonism

Mutations in the PRKN gene encoding the protein PARKIN cause Autosomal Recessive Juvenile Parkinsonism (ARJP). Harnessing this mutation to create an early-onset Parkinsons disease (PD) mouse model would provide a unique opportunity to clarify the mechanisms involved in the neurodegenerative process and lay the groundwork for the development of neuroprotective strategies. We created a knock-in mouse carrying the homozygous PrknR275W mutation, which is the missense mutation with the highest allelic frequency in PRKN patients. In PrknR275W mice, we analysed the anatomical and functional integrity of the nigrostriatal pathway, including striatal DA content and evoked striatal dopamine (DA) release, as well as the motor phenotype. We report here that PrknR275W mice show early DA neuron dysfunction, age-dependent loss of DA neurons in the substantia nigra, decreased DA content and stimulus-evoked DA release in the striatum, and progressive motor impairment. Together, these data show that the PrknR275W mouse recapitulates key features of ARJP. Thus, these studies fill a critical need in the field by introducing a promising new PD model in which to study causative mechanisms of the disease, as well as test therapeutic strategies.

neuroscience↗

bioRxiv2021

Peptide fusion improves prime editing efficiency

Prime editing enables search-and-replace genome editing but is limited by low editing efficiency. We present a high-throughput approach, PepSEq, to measure how fusion of 12,000 85-amino acid peptides derived from human DNA repair-related proteins influences prime editing efficiency. We show that peptide fusion can enhance prime editing, prime-enhancing peptides combine productively, and a top dual peptide-prime editor increases prime editing significantly in multiple cell lines across dozens of target sites.

bioengineering↗