Autism subtypes identified using cross-species functional connectivity analyses Marco Pagani, Valerio Zerbi, Silvia Gini, Filomena Grazia Alvino, Abhishek Banerjee, et al. Nature Neuroscience, 2026 It is often assumed that phenotypic heterogeneity in autism reflects underlying pathobiological variation. However, direct evidence supporting this link is lacking. Leveraging cross-species functional neuroimaging, we show that brain dysconnectivity patterns in autism can be parsed into biologically dissociable subtypes. Specifically, we found that functional magnetic resonance imaging (fMRI) connectivity alterations in 20 distinct genetic mouse models of autism cluster into hypoconnectivity-dominant and hyperconnectivity-dominant subtypes. These subtypes are linked to distinct biological pathways, with hypoconnectivity being associated with synaptic dysfunction and hyperconnectivity reflecting transcriptional and immune-related alterations. Here we identified analogous hypoconnectivity and hyperconnectivity subtypes in a multicenter human fMRI dataset of n = 940 individuals with idiopathic autism and n = 1,036 neurotypical individuals. The human autism subtypes are highly replicable, are associated with distinct functional network architectures and behavioral profiles and recapitulate the synaptic and immune-related pathways identified in the rodent dataset. Our work provides a new empirical framework for targeted subtyping of the autism spectrum.
Modified Carbon Nanotubes Favor Fibroblast Growth by Tuning the Cell Membrane Potential Giulia Suarato, Samuel Pressi, Enzo Menna, Massimo Ruben, Enrica Maria Petrini, et al. ACS Applied Materials and Interfaces, 2024 As is known, carbon nanotubes favor cell growth in vitro, although the underlying mechanisms are not yet fully elucidated. In this study, we explore the hypothesis that electrostatic fields generated at the interface between nonexcitable cells and appropriate scaffold might favor cell growth by tuning their membrane potential. We focused on primary human fibroblasts grown on electrospun polymer fibers (poly(lactic acid)─PLA) with embedded multiwall carbon nanotubes (MWCNTs). The MWCNTs were functionalized with either the p-methoxyphenyl (PhOME) or the p-acetylphenyl (PhCOMe) moiety, both of which allowed uniform dispersion in a solvent, good mixing with PLA and the consequent smooth and homogeneous electrospinning process. The inclusion of the electrically conductive MWCNTs in the insulating PLA matrix resulted in differences in the surface potential of the fibers. Both PLA and PLA/MWCNT fiber samples were found to be biocompatible. The main features of fibroblasts cultured on different substrates were characterized by scanning electron microscopy, immunocytochemistry, Rt-qPCR, and electrophysiology revealing that fibroblasts grown on PLA/MWCNT reached a healthier state as compared to pure PLA. In particular, we observed physiological spreading, attachment, and Vmem of fibroblasts on PLA/MWCNT. Interestingly, the electrical functionalization of the scaffold resulted in a more suitable extracellular environment for the correct biofunctionality of these nonexcitable cells. Finally, numerical simulations were also performed in order to understand the mechanism behind the different cell behavior when grown either on PLA or PLA/MWCNT samples. The results show a clear effect on the cell membrane potential, depending on the underlying substrate.
The BrightEyes-TTM as an open-source time-tagging module for democratising single-photon microscopy Alessandro Rossetta, Eli Slenders, Mattia Donato, Sabrina Zappone, Francesco Fersini, et al. Nature Communications, 2022 Fluorescence laser-scanning microscopy (LSM) is experiencing a revolution thanks to new single-photon (SP) array detectors, which give access to an entirely new set of single-photon information. Together with the blooming of new SP LSM techniques and the development of tailored SP array detectors, there is a growing need for (i) DAQ systems capable of handling the high-throughput and high-resolution photon information generated by these detectors, and (ii) incorporating these DAQ protocols in existing fluorescence LSMs. We developed an open-source, low-cost, multi-channel time-tagging module (TTM) based on a field-programmable gate array that can tag in parallel multiple single-photon events, with 30 ps precision, and multiple synchronisation events, with 4 ns precision. We use the TTM to demonstrate live-cell super-resolved fluorescence lifetime image scanning microscopy and fluorescence lifetime fluctuation spectroscopy. We expect that our BrightEyes-TTM will support the microscopy community in spreading SP-LSM in many life science laboratories.
Electrostatic polarization fields trigger glioblastoma stem cell differentiation Tamara Fernandez Cabada, Massimo Ruben, Amira El Merhie, Remo Proietti Zaccaria, Alessandro Alabastri, et al. Nanoscale Horizons, 2022 Glioblastoma cancer stem-like cells seeded on substrates exhibiting surface potential differences, undergo differentiation due to the forced hyperpolarization of the membrane potential at the cell/substrate interface.
Genetic Code Expansion and Click-Chemistry Labeling to Visualize GABA-A Receptors by Super-Resolution Microscopy Alexander Kuhlemann, Gerti Beliu, Dieter Janzen, Enrica Maria Petrini, Danush Taban, et al. Frontiers in Synaptic Neuroscience, 2021 Fluorescence labeling of difficult to access protein sites, e.g., in confined compartments, requires small fluorescent labels that can be covalently tethered at well-defined positions with high efficiency. Here, we report site-specific labeling of the extracellular domain of γ-aminobutyric acid type A (GABA-A) receptor subunits by genetic code expansion (GCE) with unnatural amino acids (ncAA) combined with bioorthogonal click-chemistry labeling with tetrazine dyes in HEK-293-T cells and primary cultured neurons. After optimization of GABA-A receptor expression and labeling efficiency, most effective variants were selected for super-resolution microscopy and functionality testing by whole-cell patch clamp. Our results show that GCE with ncAA and bioorthogonal click labeling with small tetrazine dyes represents a versatile method for highly efficient site-specific fluorescence labeling of proteins in a crowded environment, e.g., extracellular protein domains in confined compartments such as the synaptic cleft.
Long-term plasticity of inhibitory synapses in the hippocampus and spatial learning depends on matrix metalloproteinase 3 Grzegorz Wiera, Katarzyna Lebida, Anna Maria Lech, Patrycja Brzdąk, Inge Van Hove, et al. Cellular and Molecular Life Sciences, 2021 Learning and memory are known to depend on synaptic plasticity. Whereas the involvement of plastic changes at excitatory synapses is well established, plasticity mechanisms at inhibitory synapses only start to be discovered. Extracellular proteolysis is known to be a key factor in glutamatergic plasticity but nothing is known about its role at GABAergic synapses. We reveal that pharmacological inhibition of MMP3 activity or genetic knockout of the Mmp3 gene abolishes induction of postsynaptic iLTP. Moreover, the application of exogenous active MMP3 mimics major iLTP manifestations: increased mIPSCs amplitude, enlargement of synaptic gephyrin clusters, and a decrease in the diffusion coefficient of synaptic GABAA receptors that favors their entrapment within the synapse. Finally, we found that MMP3 deficient mice show faster spatial learning in Morris water maze and enhanced contextual fear conditioning. We conclude that MMP3 plays a key role in iLTP mechanisms and in the behaviors that presumably in part depend on GABAergic plasticity.
