Biology subjects

Cappello, V.

Publications and source records attributed to Cappello, V..

5 recordsLinked to original sources

bioRxiv2025

HPDL is critical in human cortical development via regulation of mitochondrial functional properties

Human brain development is highly regulated by several spatiotemporal processes, which disruption can result in severe neurological disorders. Emerging evidence highlights the pivotal role of mitochondrial function as one of these fundamental pathways involved in neurodevelopment. Our study investigates the role of 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) protein in cortical neurogenesis and mitochondrial activity, since mutations in the HPDL gene are associated with SPG83, a childhood-onset form of hereditary spastic paraplegia characterized by corticospinal tract degeneration and cortical abnormalities. Starting from mutant neuroblastoma cells, we demonstrated that HPDL is essential to mitochondrial respiratory chain supercomplex assembly and cellular redox balance. Moreover, transcriptomic analyses revealed dysregulated pathways related to neurogenesis, implicating HPDL role in early cortical development. To further elucidate the role of HPDL, we generated cortical neurons and organoids from SPG83 patient-derived induced pluripotent stem cells. Mutant cells exhibited premature neurogenesis at early differentiation stages, likely leading to depletion of cortical progenitors, as evidenced by decreased proliferation, slight increase of apoptosis, and unbalanced cortical type composition at later stages. Furthermore, cortical organoids derived from SPG83 patients showed impaired growth, reminding microcephaly observed in severe cases. In addition, mitochondrial morpho-functional characterization in mutant neurons confirmed disruption of OxPhos chain functionality and increased ROS generation rate. Treatment of cortical cells with two antioxidant compounds, could partially revert premature neurogenesis. In conclusion, our findings reveal a critical role for HPDL in coordinating cortical progenitor proliferation, neurogenesis, and mitochondrial function. These insights shed light on a mechanistical understanding of SPG83 pathology and underscore the therapeutic potential of targeting oxidative stress in this and related neurological disorders.

neuroscience↗

bioRxiv2025

The extremely low mechanical force generated by nano-pulling induces global changes in the microtubule network, nuclear morphology, and chromatin transcription in neurons

Mechanical force plays a pivotal role in every aspect of axon development. In this paper, we explore the use of nano-pulling, a technology that enables the intracellular generation of extremely low mechanical forces. We demonstrate that force-mediated axon growth also exerts global effects that extend to the nuclear level. Our mechanistic studies support a model in which exogenous forces induce stabilization of microtubules, and a significant remodeling of perinuclear microtubules, which preferentially align perpendicularly to the nuclear envelope. We observed an increase in the lateral tension of the nucleus, leading to substantial remodelling of nuclear morphology, characterized by an increase in nuclear grooves and higher sphericity index (indicating less flattened nuclei). Notably, these changes in nuclear shape are linked to chromatin remodelling, resulting in global transcriptional activation.

neuroscience↗

bioRxiv2024

A Transfection-Free Approach of Gene Editing via a gold-based nanoformulation of the Cas9 protein

In recent years, the CRISPR/Cas9 technology has emerged as a highly efficient tool for cell gene editing. However, the delivery of the CRISPR/Cas9 system into cells remains a significant challenge, drastically limiting in vivo gene therapy applications. In this study, we present a transfection/transduction-free tool for intracellular delivery of the Cas9:gRNA ribonucleoprotein. The Cas9 enzyme is conjugated to a 12 nm gold nanoparticle through affinity binding between the 6x His-tag of the protein and the NTA-Ni{superscript 2}LJ groups on the nanoparticles. This link chemistry allows a fine control of the density of the enzymes decorating the particle surface, the orientation of the bonding and the stability of the interaction. Importantly, the surface chemistry of this nanoformulation has been precisely engineered to modulate the cellular internalization and localization. Thanks to this approach of precision chemistry, this nanoformulation demonstrated the ability to spontaneously enter human melanoma cells as monodispersed particles that localize in cell cytoplasm, endosomes, and nucleus. It also shows effective gene editing efficiency similarly to conventional transfection tools. This gold-based formulation of Cas9 represents a ready-to-use biotech editing tool, and a promising solution for direct in vivo gene editing applications.

molecular biology↗

bioRxiv2022

Low forces push the maturation of neural precursors into neurons

Mechanical stimulation modulates neural development and neuronal activity. In a previous study, we proposed magnetic "nano-pulling" as a tool to generate active forces. By loading neural cells with magnetic nanoparticles (MNPs), a precise force vector is remotely generated through static magnetic fields. In the present study, human neural stem cells (NSCs) were subjected to a standard differentiation protocol, in the presence or absence of nano-pulling. Under mechanical stimulation, we found an increase in the length of the neural processes which showed an enrichment in microtubules, endoplasmic reticulum, and mitochondria. A stimulation lasting up to 52 days induced a strong remodelling at the level of synapse density and a re-organization of the neuronal network, halving the time required for the maturation of neural precursors into neurons. We then injected the MNP-loaded NSCs into mouse spinal cord slices, demonstrating that nano-pulling stimulates the elongation of the NPC processes and modulates their orientation even in an ex vivo model system. To the best of our knowledge, this is the first evidence showing that active mechanical stimuli can guide the outgrowth of NSCs transplanted into the spinal cord tissue. Our findings suggest that MNPs play an important role in neuronal maturation which could be applied in regenerative medicine.

neuroscience↗

bioRxiv2022

Axonal plasticity in response to active forces generated through magnetic nano-pulling

Mechanical force is crucial in guiding axon outgrowth, before and after synapse formation. This process is referred to as "stretch-growth". However, how neurons transduce mechanical inputs into signaling pathways remains poorly understood. Another open question is how stretch-growth is coupled in time with the intercalated addition of new mass along the entire axon. Here, we demonstrate that active mechanical force generated by magnetic nano-pulling induces a remodeling of the axonal cytoskeleton. Specifically, the increase in the axonal density of microtubules leads to an accumulation of organelles and signaling vesicles which, in turn, promotes local translation by increasing the probability of assembly of the "translation factories". The modulation of axonal transport and local translation sustains enhanced axon outgrowth and synapse maturation.

neuroscience↗