Biology subjects

Falconieri, A.

Publications and source records attributed to Falconieri, A..

4 recordsLinked to original sources

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↗

bioRxiv2023

Nano-pulling stimulates axon regeneration in dorsal root ganglia by inducing stabilization of axonal microtubules and activation of local translation

Axonal plasticity is a phenomenon strongly related to neuronal development as well as regeneration. Recently, it has been demonstrated that active mechanical tension, intended as an extrinsic factor, is a valid contribution to the modulation of axonal plasticity. In previous publications, our team validated a method, the "nano-pulling", for applying mechanical forces on developing axons of isolated primary neurons using magnetic nanoparticles (MNP) actuated by static magnetic fields. This method was found to promote axon growth and synaptic maturation. Here, we explore the possibility to use nano-pulling as an extrinsic factor to promote axon regeneration in a neuronal tissue explant. Having this in mind, whole dorsal root ganglia (DRG) have been dissected from mouse spinal cord, incubated with MNPs, and then stretched. We found that particles were able to penetrate the ganglion and to localise both into the somas and in sprouting axons. Our results point that the nano-pulling doubles the regeneration rate, documented by an increase in the arborizing capacity of axons, and an accumulation of cellular organelles related to mass addition (endoplasmic reticulum and mitochondria) with respect to spontaneous regeneration. In line with the previous results on isolated hippocampal neurons, we observed an increase in the density of stable microtubules and activation of local translation in stretched ganglions. The collected data demonstrate that the nano-pulling is able to enhance axon regeneration in whole spinal ganglia exposed to MNPs and external magnetic fields. The preliminary data represent an encouraging starting point for proposing the nano-pulling as biophysical tool to design novel therapies based on the use of force as an extrinsic factor for promoting nerve regeneration.

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↗

bioRxiv2020

The E3 ubiquitin-protein ligase MDM2 is a novel interactor of the von Hippel-Lindau tumor suppressor

Mutations of the von Hippel-Lindau (pVHL) tumor suppressor are causative of a familiar predisposition to develop different types of cancer. pVHL is mainly known for its role in regulating hypoxia-inducible factor 1- (HIF-1) degradation, thus modulating the hypoxia response. There are different pVHL isoforms, including pVHL30 and pVHL19. However, little is known about isoform-specific functions and protein-protein interactions. Integrating in silico predictions with in vitro and in vivo assays, we describe a novel interaction between pVHL and mouse double minute 2 homolog (MDM2). Importantly, we found that pVHL30, and not pVHL19, forms a complex with MDM2, and that the N-terminal acidic tail of pVHL30 is required for its association with MDM2. Further, we demonstrate that an intrinsically disordered region upstream of the tetramerization domain of MDM2 is responsible for its isoform-specific association with pVHL30. This region is highly conserved in higher mammals, including primates, similarly to what has been already proposed for the N-terminal tail of pVHL30. Finally, we show that overexpression of pVHL30 and MDM2 together reduces cell proliferation, suggesting a synergistic effect of these E3 ubiquitin ligases. Collectively, our data support the idea that pVHL30 plays a role in MDM2 regulation, suggesting a wider interplay among hypoxia sensing and cell cycle regulation.

biochemistry↗