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Salmaso, N.

Publications and source records attributed to Salmaso, N..

5 recordsLinked to original sources

Sex-specific hormone-sensitive regulatory architecture in adolescence as a scaffold for depression vulnerability

Adolescence is a critical developmental period during which sex differences in depression risk emerge, yet the underlying molecular mechanisms remain unclear. Here, we integrated longitudinal transcriptomic, epigenomic, and gene regulatory network analyses to characterize sex-specific regulatory dynamics of the brain across adolescence under normative conditions and elucidate how baseline molecular differences may shape later vulnerability. We observed that immediate early genes exhibited the strongest sex-biased signals, with males and females showing opposing developmental trajectories, suggesting a role in sex-specific stress-responsive programs. Across analyses, a consistent pattern emerged: males showed stronger activity-dependent neuronal signatures, whereas females showed stronger stress- and immune-related signatures. Extending these findings to a disease context using single-nucleus chromatin accessibility data, we identified hormone-responsive regulatory elements enriched in depression-associated regions, with sex- and cell type-specific links to genetic risk. Grounded in established models of sex-specific stress responses, these findings offer a developmental regulatory framework for understanding the differential presentation of, and vulnerability to, depression.

genomics↗

Optogenetic stimulation of nigral astrocytes is neuroprotective in a 6-OHDA model of neurodegeneration.

HighlightsO_LIOptogenetic stimulation of nigral astrocytes attenuates motor deficits & Th+ cell loss in a 6-OHDA model of neurodegeneration C_LIO_LIBulk RNA-seq analysis reveals optogenetic stimulation of nigral astrocytes induces early changes in microglia C_LIO_LIsnRNA-seq shows 6-OHDA alone induces extensive gene expression changes across all cell populations within the SN C_LIO_LIOligodendrocytes within the SNc express Th, which is upregulated with DA neuron loss C_LI Parkinsons disease is characterized by the loss of dopaminergic neurons in the substantia nigra. Glial-glial crosstalk is essential for maintaining the regional milieu, and appears to be particularly important in modulating neuroinflammation and many aspects of neurodegeneration. In particular, astrocytes are critical for maintaining dopamine neuronal integrity and survival, and astroglial dysfunction is prominent in Parkinsons disease. As such, astrocytes represent a potentially critical therapeutic target in neurodegeneration. In this study, in vivo optogenetics were used to selectively stimulate astrocytes in the substantia nigra following a striatal 6-OHDA lesion. Remarkably, a single bout of optogenetic stimulation was sufficient to attenuate motor deficits and dopamine neuron loss induced by the neurotoxin. Furthermore, bulk RNA-seq and snRNA-seq analysis of the substantia nigra revealed extensive changes in both microglia and oligodendrocytes, suggesting that the neuroprotective effects of stimulating astrocytes may be mediated through alterations in glia-glia crosstalk. Altogether, this work demonstrates the importance of understanding glia-glia interactions in neurodegeneration.

neuroscience↗

Astroglial Hmgb1 regulates postnatal astrocyte morphogenesis and cerebrovascular maturation.

Astrocytes are intimately linked with brain vessels, a relationship that is critical for neuronal health and function. However, astroglial factors driving these physical and functional associations during postnatal brain development have yet to be identified. We characterized structural and transcriptional changes in mouse cortical astrocytes and microvessels during the first two postnatal weeks and found that high-mobility group box 1 (Hmgb1), normally upregulated with injury and involved in adult cerebrovascular repair, was highly expressed in astrocytes at birth and then decreased rapidly. Astrocyte-selective ablation of Hmgb1 at birth affected astrocyte morphology and endfoot placement, altered distribution of endfoot proteins connexin43 and aquaporin-4, induced transcriptional changes in astrocytes related to cytoskeleton remodeling, and profoundly disrupted endothelial ultrastructure. While lack of astroglial Hmgb1 did not affect the blood-brain barrier or angiogenesis postnatally, it impaired neurovascular coupling and behavior in adult mice. These findings identify astroglial Hmgb1 as a key player in postnatal gliovascular maturation.

developmental biology↗

A step-by-step sequence-based analysis of virome enrichment protocol for freshwater and sediment samples

Cultivation-free metagenomic analysis afforded unprecedented details on the diversity, structure and potential functions of microbial communities in different environments. When employed to study the viral fraction of the community that is recalcitrant to cultivation, metagenomics can shed light into the diversity of viruses and their role in natural ecosystems. However, despite the increasing interest in virome metagenomics, methodological issues still hinder the proper interpretation and comparison of results across studies. Virome enrichment experimental protocols are key multi-step processes needed for separating and concentrating the viral fraction from the whole microbial community prior to sequencing. However, there is little information on their efficiency and their potential biases. To fill this gap, we used metagenomic and amplicon sequencing to examine the microbial community composition through the serial filtration and concentration steps commonly used to produce viral-enriched metagenomes. The analyses were performed on water and sediment samples from an Alpine lake. We found that, although the diversity of the retained microbial communities declined progressively during the serial filtration, the final viral fraction contained a large proportion (from 10% to 40%) of non-viral taxa, and that the efficacy of filtration showed biases based on taxonomy. Our results quantified the amount of bacterial genetic material in viromes and highlighted the influence of sample type on the enrichment efficacy. Moreover, since viral-enriched samples contained a significant portion of microbial taxa, computational sequence analysis should account for such biases in the downstream interpretation pipeline. ImportanceFiltration is a commonly used method to enrich viral particles in environmental samples. However, there is little information on its efficiency and potential biases on the final result. Using a sequence-based analysis on water and sediment samples, we found that filtration efficacy is dependent on sample type and that the final virome contained a large proportion of non-viral taxa. Our finding stressed the importance of downstream analysis to avoid biased interpretation of data.

microbiology↗

Translatomic database of cortical astroglia across male and female mouse development reveals two distinct developmental phenotypes

Astroglial cells are emerging as key players in the development and homeostatic maintenance of neurons and neuronal networks. Astroglial cell functions are critical to neuronal migration and maturation, myelination, and synapse dynamics, however little is known about astroglial phenotypic changes over development. Furthermore, astroglial cells express steroid hormone receptors and show rapid responses to hormonal manipulations, however, despite important sex differences in telencephalic regions such as the cortex and hippocampus few studies have examined sex differences in astroglial cells in development and outside of the hypothalamus and amygdala. To phenotype cortical astroglial cells across postnatal development while considering potential sex differences, we used translating ribosome affinity purification together with RNA sequencing (TRAPseq) and immunohistochemistry to phenotype the entire astroglial translatome in males and females at key developmental time points: P1, P4, P7, P14, P35 and in adulthood. Overall, we found two distinct astroglial phenotypes between early (P1-P7) and late development (P14-Adult). We also noted that although astroglia show few basal sex differences in adulthood, they show significant sex differences in developmental gene expression patterns, with peak sex differences observed at P7. At least part of the sex differences observed at P7 appear to be due to males reaching a more mature astroglial phenotype earlier than females. Together, these data clearly delineate and phenotype astroglia across development and identify sex differences in astroglial developmental programs. Importantly, these developmental sex differences could have an impact on the construction and maintenance of neuronal networks and potential developmental windows of vulnerability to neurologic and psychiatric disease.

neuroscience↗