Biology subjects

Rubino, B.

Publications and source records attributed to Rubino, B..

3 recordsLinked to original sources

bioRxiv2025

Genome shuffling enables quantitative trait locus mapping in Bacillus subtilis

Genetic mapping is a powerful tool for eukaryotic genetics that has only been applied to bacteria in limited circumstances. Quantitative trait locus (QTL) mapping generally relies on sexual recombination to break linkages between genes, yet bacteria rarely undergo sufficient homologous recombination to generate suitable mapping populations. In this work, we used iterative biparental genome shuffling by protoplast fusion in Bacillus subtilis to generate a population of bacteria with substantial random recombination throughout their genomes. Individual shuffled progeny were arrayed in well plates, resequenced, and characterized for a range of complex phenotypes including spore germination and swarming motility. Genetic mapping of the resulting phenotypes identified high-confidence QTLs of moderate size ([~]10 kb), and these associations were validated through targeted genetic swaps. This B. subtilis QTL population can easily be used to map additional phenotypes, and the general approach for QTL mapping is applicable in a wide range of bacteria. One-Sentence SummaryBacterial genome shuffling mimics sexual recombination and enables genetic mapping of complex phenotypes to causal alleles.

microbiology↗

bioRxiv2024

Chronic activation of astrocytic Gq GPCR signaling has causal effects on visual LTP formation: implications for neurodegenerative diseases

Astrocytes are the most abundant glial cells in the central nervous system and interact with other cell types, including neurons and microglia, via Gq protein-coupled receptors (Gq GPCRs) present on their surface. Astrocytic Gq GPCR activation induces Ca2+ release from internal stores, leading to intracellular Ca2+ elevations. There is emerging evidence supporting that astrocytic Gq GPCR Ca2+ elevations are upregulated and dysregulated in neurodegenerative diseases and are thought to play an important role in the pathogenesis of such diseases. Furthermore, astrocytic Gq GPCR Ca2+-dependent release of neuroactive or inflammatory molecules from astrocytes may occur in the early steps of the stress/inflammatory process in the diseased brain. In addition, low grade and chronic brain inflammation is involved in the etiology of neurodegenerative diseases. We hypothesized that chronic activation of astrocytic Gq GPCR Ca2+ signaling leads to an altered production of glutamate or pro-inflammatory factors from astrocytes, and consequent deficits in synaptic transmission, long-term potentiation (LTP), and memory formation. To test this hypothesis, we used an AAV-based chemogenetic tool to selectively activate astrocyte Gq GPCR Ca2+ signaling combined with in vivo electrophysiology, immunohistochemistry, and biochemistry. Using the mouse primary visual cortex (V1) as a model system, we found that chronically increased astrocytic Gq GPCR Ca2+ signaling leads to a decrease in LTP of visual-evoked potentials. Such LTP impairment was associated with microglial reactive phenotype - displaying a hyper-ramified and proliferative state - as well as a decrease in the number of interleukin 33 (IL-33)-expressing astrocytes. Our study is the first to have shown that chronic astrocytic Gq GPCR activation is sufficient to alter visual LTP and induce astrocyte-to-microglia communication, possibly through and IL-33 pathway in the adult brain. Because GPCRs are important drug targets, our study could have relevant therapeutic implications in the treatment of some neurodegenerative diseases.

neuroscience↗

bioRxiv2020

Characterization of transgenic mouse lines for selectively targeting glial cells in dorsal root ganglia

The importance of glial cells in the modulation of neuronal processes is now generally accepted. In particular, enormous progress in our understanding of astrocytes and microglia physiology in the central nervous system (CNS) has been made in recent years, due to the development of genetic and molecular toolkits. However, the roles of satellite glial cells (SGCs) and macrophages - the peripheral counterparts of astrocytes and microglia - remain poorly studied despite their involvement in debilitating conditions, such as pain. Here, we characterized in dorsal root ganglia (DRGs), different genetically-modified mouse lines previously used for studying astrocytes and microglia, with the goal to implement them for investigating DRG SGC and macrophage functions. Although SGCs and astrocytes share some molecular properties, most tested transgenic lines were found to not be suitable for studying selectively a large number of SGCs within DRGs. Nevertheless, we identified and validated two mouse lines: (i) a CreERT2 recombinase-based mouse line allowing transgene expression almost exclusively in SGCs and in the vast majority of SGCs, and (ii) a GFP-expressing line allowing the selective visualization of macrophages. In conclusion, among the tools available for exploring astrocyte functions, a few can be used for studying selectively a great proportion of SGCs. Thus, efforts remain to be made to characterize other available mouse lines as well as to develop, rigorously characterize and validate new molecular tools to investigate the roles of DRG SGCs, but also macrophages, in health and disease.

neuroscience↗