Biology subjects

Debellis, D.

Publications and source records attributed to Debellis, D..

5 recordsLinked to original sources

bioRxiv2024

A photo-switchable gold nanoformulation based on the dCas9 protein for spatiotemporal controlled gene editing activation in vivo

Genome editing allows for the manipulation of genomic DNA for biotechnology and biomedical applications, but the specificity and control of the editing process remain a challenge. This study introduces a nano-switch for spatiotemporal control of the editing process. The basic module of the nano-switch (the monomer) is composed of a gold nanorod conjugated with the dead Cas9. Based on mathematical models, we established the design and the mechanism of action of the nano-switch. Briefly, when two monomers, guided by their respective guide RNAs, form a dimer onto the DNA and get irradiated with a Near-Infrared pulsed laser resonant at the plasmonic properties of the dimer, they generate a localized heat that triggers a thermal break onto the DNA. The nano-switch was generated, validated, and tested in zebrafish embryos at the 1-cell stage. Molecular analysis of irradiated embryos showed targeted DNA mutations, validating the efficacy of the nano-switch as a tool for conditional gene editing that integrates the if-when-where functions.

molecular biology↗

bioRxiv2024

Monitoring myelin lipid composition and structure of myelinated fibers reveals a maturation delay in CMT1A

1.Findings accumulated over time show that neurophysiological, neuropathological, and molecular alterations are present in CMT1A and support the dysmyelinating rather than demyelinating nature of this neuropathy. Moreover, uniform slowing of nerve conduction velocity is already manifest in CMT1A children and does not improve throughout their life. This evidence and our previous studies displaying aberrant myelin composition and structure in adult CMT1A rats prompt us to hypothesize a myelin and axon developmental defect in the CMT1A peripheral nervous system. Peripheral myelination begins during the early stages of development in mammals and, during this process, chemical and structural features of myelinated fibers (MFs) evolve towards a mature phenotype; deficiencies within this self-modulating circuit can cause its blockage. Therefore, to shed light on pathophysiological mechanisms that occur during development, and to investigate the relationship among axonal, myelin, and lipidome deficiencies in CMT1A, we extensively analyzed the evolution of both myelin lipid profile and MF structure in WT and CMT1A rats. Lipidomic analysis revealed a delayed maturation of CMT1A myelin already detectable at P10 characterized by deprivation of sphingolipid species such as hexosylceramides and long-chain sphingomyelins, whose concentration physiologically increases in WT, and an increase in lipids typical of unspecialized plasma membranes, including phosphatidylcholines and phosphatidylethanolamines. Consistently, advanced morphometric analysis on more than 130.000 MFs revealed a delay in the evolution of CMT1A axon and myelin geometric parameters, appearing concomitantly with lipid impairment. We here demonstrate that, during normal development, MFs undergo a continuous maturation process in both chemical composition and physical structure, but these processes are delayed in CMT1A.

neuroscience↗

bioRxiv2023

YAP signaling regulates the cellular uptake and therapeutic effect of nanoparticles

Interactions between living cells and nanoparticles have been extensively studied to enhance the delivery of therapeutics. Nanoparticles size, shape, stiffness and surface charge have been regarded as the main features able to control the fate of cell-nanoparticle interactions. However, the clinical translation of nanotherapies has so far been limited, and there is a need to better understand the biology of cell-nanoparticle interactions. This study investigated the role of cellular mechanosensitive components in cell-nanoparticle interactions. We demonstrate that the genetic and pharmacologic inhibition of yes-associated protein (YAP), a key component of cancer cell mechanosensing apparatus and Hippo pathway effector, improves nanoparticle internalization in triple-negative breast cancer cells regardless of nanoparticle properties or substrate characteristics. This process occurs through YAP-dependent regulation of endocytic pathways, cell mechanics, and membrane organization. Hence, we propose targeting YAP may sensitize triple negative breast cancer cells to chemotherapy and increase the selectivity of nanotherapy.

bioengineering↗

bioRxiv2022

Generation and Maturation of Human iPSC-derived Cardiac Organoids in Long Term Culture

Cardiovascular diseases remain the leading cause of death worldwide; hence there is an increasing focus on developing physiologically relevant in vitro cardiovascular tissue models suitable for studying personalized medicine and pre-clinical tests. Despite recent advances, models that reproduce both tissue complexity and maturation are still limited. We have established a scaffold-free protocol to generate multicellular, beating and self-organized human cardiac organoids (hCO) in vitro from hiPSCs that can be cultured for long term. This is achieved by differentiation of hiPSC in 2D monolayer culture towards cardiovascular lineage, followed by further aggregation on low-attachment culture dishes in 3D. The generated human cardiac organoids (hCOs) containing multiple cell types that physiologically compose the heart, gradually self-organize and beat without external stimuli for more than 50 days. We have shown that 3D hCOs display improved cardiac specification, survival and maturation as compared to standard monolayer cardiac differentiation. We also confirmed the functionality of hCOs by their response to cardioactive drugs in long term culture. Furthermore, we demonstrated that hCOs can be used to study chemotherapy-induced cardiotoxicity. This study could help to develop more physiologically-relevant cardiac tissue models, and represent a powerful platform for future translational research in cardiovascular biology.

cell biology↗

bioRxiv2022

Reactive microglia and cytokine release entails microtubule remodeling from acentrosomal to centrosomal arrays

Microglia reactivity entails a large-scale remodeling of cellular geometry, but the role of the microtubule cytoskeleton during these changes remains unexplored. Here we show that reactive proinflammatory microglia provide a heretofore unique example of microtubule reorganization from a non-centrosomal array of parallel and stable microtubules to a radial array of more dynamic microtubules. While in the homeostatic state microglia nucleate microtubules at Golgi outposts, proinflammatory signaling induces recruitment of nucleating material nearby the centrosome and inhibition of centrosomal maturation enhances NLRP3 inflammasome activation and secretion of IL-1{beta}. Our results demonstrate that a hallmark of microglia reactivity is a striking remodeling of the microtubule cytoskeleton and suggest that pericentrosomal microtubule nucleation may serve as a distinct marker of microglia activation as well as a novel target to modulate cytokine-mediated inflammatory responses in chronic disease and tissue injury.

cell biology↗