Blasco, E. | bioRxiv Science

bioRxiv2024

Minimal-invasive 3D laser printing of microimplants in organismo

Multi-photon 3D laser printing has gathered much attention in recent years as a means of manufacturing biocompatible scaffolds that can modify and guide cellular behavior in vitro. However, in vivo tissue engineering efforts have been limited so far to the implantation of beforehand 3D printed biocompatible scaffolds and in vivo bioprinting of tissue constructs from bioinks containing cells, biomolecules, and printable hydrogel formulations. Thus, a comprehensive 3D laser printing platform for in vivo and in situ manufacturing of microimplants raised from synthetic polymer-based inks is currently missing. Here we present a platform for minimal-invasive manufacturing of microimplants directly in the organism by one-photon photopolymerization and multi-photon 3D laser printing. Employing a commercially available elastomeric ink giving rise to biocompatible synthetic polymer-based microimplants, we demonstrate first applicational examples of biological responses to in situ printed microimplants in the teleost fish Oryzias latipes and in embryos of the fruit fly Drosophila melanogaster. This provides a framework for future studies addressing the suitability of inks for in vivo 3D manufacturing. Our platform bears great potential for the direct engineering of the intricate microarchitectures in a variety of tissues in model organisms and beyond.

bioengineering↗

bioRxiv2022

Bumetanide increases microglia-interneuron contact following traumatic brain injury

ObjectiveThe Na-K-Cl cotransporter (NKCC1) inhibitor bumetanide has prominent positive effects on the pathophysiology of many neurological disorders. Here we studied whether bumetanide could influence post-traumatic cognitive decline and inflammatory processes by regulating astrocyte and microglia activation. MethodControlled cortical impacted (CCI) animals were treated with bumetanide during the first post-CCI week. Immunochemistry, flow cytometry, immunoassay, and in vivo imaging were used to study astrocytic and microglial morphology and phenotype as well as adult neurogenesis. Telemetric electroencephalograms and cognitive behavioral test were performed at one-month post CCI. ResultsBumetanide prevented CCI-induced decrease in hippocampal neurogenesis and parvalbumin positive interneuron loss. Deletion of NKCC1 in astrocytes neither rescued interneurons nor promote neurogenesis. Interestingly, bumetanide had a strong effect on microglial activation by inducing polarization towards the M1-like phenotype 3 days post-CCI and the M2-like phenotype 7 days post-CCI. Bumetanide increased microglial Brain-derived neurotrophic factor (BDNF) expression and interaction with parvalbumin interneurons. The early treatment with bumetanide resulted in improvements in working and episodic memory, one-month post-CCI, as well as the normalization of theta band oscillations. InterpretationHere, we disclose a novel mechanism for the neuroprotective action of bumetanide mediated by an acceleration of microglial activation dynamics that leads to an increase of parvalbumin interneuron survival following CCI, possibly resulting from increased microglial BDNF expression and contact with interneurons. Salvage of interneurons may normalize ambient gamma-aminobutyric acid (GABA) resulting in the preservation of adult neurogenesis processes as well as contributing to bumetanide-mediated improvement of cognitive performance.

neuroscience↗