Biology subjects

Porcionatto, M.

Publications and source records attributed to Porcionatto, M..

8 recordsLinked to original sources

bioRxiv2024

Dissecting Reactive Astrocyte Responses: Lineage Tracing and Morphology-based Clustering

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/587565v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@1899db6org.highwire.dtl.DTLVardef@1d152fcorg.highwire.dtl.DTLVardef@19f4754org.highwire.dtl.DTLVardef@3f853_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Brain damage triggers diverse cellular and molecular events, with astrocytes playing a crucial role in activating local neuroprotective and reparative signaling within damaged neuronal circuits. Here, we investigated reactive astrocytes using a multidimensional approach to categorize their responses into different subtypes based on morphology using the StarTrack lineage tracer, single-cell imaging reconstruction and multivariate data analysis. Our findings revealed three profiles of reactive astrocyte responses affecting cell size- and shape-related morphological parameters: "moderate," "strong," and "very strong". We also explored the heterogeneity in astrocyte reactivity, with a particular emphasis in the spatial and clonal distribution. Our research highlights the importance of the relationships between the different astrocyte subpopulations with their reactive responses, showing an enrichment of protoplasmic and fibrous astrocytes within the "strong" and "very strong" subtypes. Overall, our study contributes to a better understanding of astrocyte heterogeneity in response to an injury. By elucidating the diverse reactive responses among astrocyte subpopulations, we pave the way for future research aimed at uncovering novel therapeutic targets for mitigating the effects of brain damage and promoting neural repair.

neuroscience↗

bioRxiv2021

Self-organization of in vitro neuronal assemblies drives to complex network topology

Activity-dependent self-organization plays an important role in the formation of specific and stereotyped connectivity patterns in neural circuits. By combining neuronal cultures, tools with approaches from network neuroscience and information theory, we can study how complex network topology emerges from local neuronal interactions. We constructed effective connectivity networks using a transfer entropy analysis of electrophysiological signals recorded from rat embryo dissociated hippocampal neuron cultures between 6 and 35 days in vitro to investigate how the neuronal network topology evolves during maturation. The methodology for constructing the networks considered the synapse delay and addressed the influence of firing rate and population bursts as well as spurious effects on the inference of connections. We found that the number of links in the networks grew over the course of development, shifting from a segregated to a more integrated architecture. As part of this progression, three significant aspects of complex network topology emerged. In agreement with previous in silico and in vitro studies, a small-world architecture was detected, largely due to strong clustering among neurons. Additionally, the networks developed in a modular community topology, with most modules comprising nearby neurons. Finally, highly active neurons acquired topological characteristics that made them important nodes to the network and integrators of communities. These findings leverage new insights into how neuronal effective network topology relates to neuronal assembly self-organization mechanisms.

neuroscience↗

bioRxiv2019

A novel decellularization method to produce brain scaffolds

Scaffolds composed of extracellular matrix (ECM) can assist tissue remodeling and repair following injury. The ECM is a complex biomaterial composed of proteins, glycoproteins, proteoglycans, and glycosaminoglycans, secreted by cells. The ECM contains fundamental biological cues that modulate cell behavior and serves as a structural scaffold for cell adhesion and growth. For clinical applications, where immune rejection is a constraint, ECM can be processed using decellularization methods intended to remove cells and donor antigens from tissue or organs, while preserving native biological cues essential for cell growth and differentiation. Recent studies show bioengineered organs composed by a combination of a diversity of materials and stem cells as a possibility of new therapeutic strategies to treat diseases that affect different tissues and organs, including the central nervous system (CNS). Nevertheless, the methodologies currently described for brain decellularization involve the use of several chemical reagents with many steps that ultimately limit the process of organ or tissue recellularization. Here, we describe for the first time a fast and straightforward method for complete decellularization of mice brain by the combination of rapid freezing and thawing following the use of only one detergent (Sodium dodecyl sulfate (SDS)). Our data show that using the protocol we describe here the brain can be entirely decellularized, while still maintaining ECM components that are essential for cell survival and repopulation of the scaffold. Our results also show the repopulation of the decellularized brain matrix with Neuro2a cells, that were identified by immunohistochemistry in their undifferentiated form. We conclude that this novel and simple method for brain decellularization can be used as a biocompatible scaffold for cell repopulation.\n\nImpact StatementFor the first time we describe an easy, effective and low cost method for complete decellularization of murine brain by the use of only one detergent (SDS) combined with rapid freezing and thawing, that can be used as a 3D scaffold for cell culture of neuronal cells. The results show that the decellularized brains still maintain ECM components essential for cell survival and repopulation of the scaffold. Moreover, we found that the decellularized brain matrix can be repopulated with neural cells, showing its biocompatibility.\n\nGRAFICAL ABSTRACT\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC=\"FIGDIR/small/680702v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (26K):\norg.highwire.dtl.DTLVardef@15fd027org.highwire.dtl.DTLVardef@15acfeborg.highwire.dtl.DTLVardef@1087d2eorg.highwire.dtl.DTLVardef@529309_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2019

Decreased viability and neurite length in neural cells treated with chitosan-dextran sulfate nanocomplexes

CXCL12 is a chemokine known to regulate migration, proliferation, and differentiation of neural stem cells (NSCs) and to play a neuroprotective role in ischemic stroke. Chitosan-dextran sulfate nanocomplexes (Ch/DS NC) are known nanoparticulated systems used to efficiently deliver heparin-binding factors. Here we evaluate Ch/DS NC as carriers for CXCL12 in a mouse model of stroke. Free CXCL12 reduced the size of the ischemic brain lesion. However, when Ch/DS NC were administrated, the stroke volume increased. Neurotoxic screening revealed that Ch/DS NC reduced neuronal viability, decreased the extension of neurites and impaired NSC migration in vitro. To the best of our knowledge, neurotoxicity of Ch/DS NC has not been reported and further screenings will be needed in order to evaluate the biological safety of these nanocomposites. Our results add new data on nanoparticle neurotoxicity and may help us to better understand the complex interactions of the nanostructures with biological components.

neuroscience↗

bioRxiv2019

Intraventricular CXCL12 is neuroprotective and increases neurogenesis in a murine model of stroke

Stroke is the leading cause of physical disability and the second leading cause of death in adults. Chemokines that regulate ischemic microenvironment can influence neurorestorative therapies in stroke patients. CXCL12 was shown to be neuroprotective, but there are some contradictory results in the literature. The objective of this work is to verify whether CXCL12 delivery to the brain could be beneficial or harmful. We decided to evaluate the intraventricular delivery to facilitate its application in clinical practice. Intraventricular CXCL12 was able to produce increased mRNA expression of the receptors CXCR4 and CXCR7 in the cerebral cortex. After the stroke, intraventricular CXCL12 decreased mice ischemic area and improved behavioral response. We found CXCL12 was neuroprotective, increase reactive astrogliosis and improve neurogenesis in the perilesional area.

neuroscience↗

bioRxiv2018

A new function for Prokineticin 2: recruitment of SVZ-derived neuroblasts to the injured cortex in a mouse model of traumatic brain injury

Traumatic brain injury is an important cause of mortality and morbidity all over the world. After the initial injury there is a cascade of cellular and molecular events that ultimately lead to cell death. Therapies aim not only to counteract these mechanisms but also to replenish the lost cell population in order to achieve a better recovery. The adult mammal brain in not as plastic as the postnatal, but it has at least two neurogenic regions that maintains physiological functions in the brain; the subgranular zone of the dentate gyrus of the hippocampus, which produces neurons that integrate locally, and the subventricular zone (SVZ) of the lateral ventricles, that produces neuroblasts that migrate through the rostral migratory stream (RMS) to the olfactory bulbs. Brain injuries, as well as neurodegenerative diseases, induce the SVZ to respond by increasing cell proliferation and migration to the injured areas. Here we report that SVZ cells migrate to the injured cortex after traumatic brain injury in mice, and that the physiological RMS migration is not impaired. We also show that Prokineticin 2 (PROK2), a chemokine important for the olfactory bulb neurogenesis by promoting the directional migration of neuroblasts, is induced in the injured cortex. Using PROK2 receptor antagonist and recombinant PROK2 we show for the first time that PROK2 can directionally attract SVZ cells in vitro and in vivo. The data we present here links one more element of the inflammatory process, PROK2 secreted by microglia, to the attempt to regenerate an acutely injured mammalian cortex.\n\nAbbreviations

neuroscience↗

bioRxiv2017

Polypyrrole increases branching and neurite extension by Neuro2A cells on PBAT ultrathin fibers

Graphical Abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC=\"FIGDIR/small/241307_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (30K):\norg.highwire.dtl.DTLVardef@142856dorg.highwire.dtl.DTLVardef@45d372org.highwire.dtl.DTLVardef@3d1af3org.highwire.dtl.DTLVardef@1b48530_HPS_FORMAT_FIGEXP M_FIG C_FIG Electrospinning shows a feasible way to generate hybrid scaffolds from the combination of different materials. This work presented a successful route to prepare ultrathin fibers from hybrid solutions containing a commercial polyester, poly (butylene adipate-co-terephthalate) (PBAT) and a conductive polymer, polypyrrole (PPy). The final material (PBAT/PPy) showed an enhanced potential for neuronal differentiation when compared to neat PBAT. The PPy loading improved branching and neurite extension of Neuro2a cells, which opens a wide range of perspectives where these materials may be applied in regenerative medicine.\n\nABSTRACTWe present a methodology for production and application of electrospun hybrid materials containing commercial polyester (poly (butylene adipate-co-terephthalate; PBAT), and a conductive polymer (polypirrole; PPy) as scaffold for neuronal growth and differentiation. The physical-chemical properties of the scaffolds and optimization of the electrospinning parameters are presented. The electrospun scaffolds are biocompatible and allow proper adhesion and spread of mesenchymal stem cells (MSCs). Fibers produced with PBAT with or without PPy were used as scaffold for Neuro2a mouse neuroblastoma cells adhesion and differentiation. Neuro2a adhered to PBAT and PBAT/PPy2% scaffolds without laminin coating. However, Neuro2a failed to differentiate in PBAT when stimulated by treatment with retinoic acid (RA), but differentiated in PBAT/PPy2% fibers. We hypothesize that PBAT hydrophobicity inhibited proper spreading and further differentiation, and inhibition was overcome by coating the PBAT fibers with laminin. We conclude that fibers produced with the combination of PBAT and PPy can support neuronal differentiation.

bioengineering↗

bioRxiv2017

Rotary jet-spun porous microfibers as scaffolds for stem cells delivery to central nervous system injury

Transplanting stem cells into the central nervous system is a promising therapeutic strategy. However, preclinical trials of cell-based therapies are limited by poor local cell engraftment and survival. Here, we present a polylactic acid (PLA) scaffold to support delivery of mesenchymal stem cells (MSCs) in a mouse model of stroke. We isolated bone marrow MSCs from adult C57/Bl6 mice, cultured them on PLA polymeric rough microfibrous (PLA-PRM) scaffolds obtained by rotary jet spinning, and transplanted into the brains of adult C57/Bl6 mice, carrying thermocoagulation-induced cortical stroke. Interleukins (IL4, IL6 and IL10) and tumor necrosis factor alfa (TNF) expression levels in the brain of mice that received PRM were similar to untreated. MSCs transplantation significantly reduced the area of the lesion and PRM delivery increased MSCs retention at the injury site. We conclude that PLA-PRM scaffolds offer a promising new system to deliver stem cells to injured areas of the brain.\n\nGRAPHICAL ABSTRACT O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY\n\nSynthetic scaffolds offer an alternative to optimize stem cell transplantation at sites of brain injury. Here, we present a rotary jet spun polylactic acid (PLA) polymer used as a scaffold to support delivery of mesenchymal stem cells (MSCs) in a mouse model of stroke. Transplantation of MSCs isolated or cultured on PRM significantly reduced the area of the lesion and PRM delivery increased MSCs retention at the injury site.

neuroscience↗