Biology subjects

Dovero, S.

Publications and source records attributed to Dovero, S..

5 recordsLinked to original sources

bioRxiv2025

Duchenne muscular dystrophy is driven by defective membrane repair and annexin-A2 dysregulation in skeletal muscle

BackgroundDuchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene, which encodes dystrophin in skeletal muscle cells. Although the role of dystrophin as a structural protein is well known, the cellular processes underlying myofiber degeneration are still not fully understood. Despite advances from studies in murine models, these models do not fully replicate the human pathology. MethodsWe investigated sarcolemmal integrity, membrane repair capacity, and annexin protein expression in DMD patient muscle biopsies and human skeletal muscle cell lines using immunohistochemistry, both shear stress-based and laser irradiation injury assays, western blotting, and live-cell imaging of GFP-tagged annexins. ResultsWe identified defective membrane repair in DMD skeletal muscle cells, independent of increased membrane fragility, by evaluating resealing capacity in control and DMD derived-patient cell lines using both a shear stress assay (N = l2, p < 0.000l) and a laser irradiation assay (N = 3, p < 0.000l). Analyses performed on human DMD muscle biopsies (N = l0) further confirmed this defect, demonstrating massive intracellular IgG uptake (p < 0.000l) together with altered annexin expression profiles. While mechanical stress induces the upregulation of annexin A5 (ANXA5, p < 0.0l) and A6 (ANXA6, p < 0.05) in healthy skeletal muscle cells - suggesting an adaptive response to membrane damage, given the annexin familys central role in membrane repair - we observed dysregulated expression patterns of these proteins in DMD cells. Notably, ANXAl (p < 0.05) and ANXA2 (p < 0.0l) were not only significantly overexpressed but also aberrantly localized to the extracellular space, a putative consequence of defective membrane repair. Since extracellular ANXA2 has been associated with adipocyte accumulation in the muscle tissue of patients with dysferlinopathy, a similar pathological mechanism may be at play in DMD. ConclusionsOur findings propose that ANXA2 contributes to muscle degeneration in DMD and highlight it as a potential therapeutic target to prevent adipogenesis and muscle loss.

cell biology↗

bioRxiv2025

A subset of dorsal raphe dopamine neurons is critical for survival-oriented vigilance.

Defensive behaviors are essential for survival, with risk assessment enabling organisms to evaluate and respond to potential threats. The dorsal raphe nucleus (DRN), a key neuromodulatory center, is crucial for encoding motivational salience and regulating arousal and sleep-wake states through its diverse neuronal populations, including dopaminergic neurons (DRNDA). While the roles of DRNDA neurons have been studied, their specific contributions to threat evaluation are less understood. Recent research identifies a distinct subset of DRNDA neurons that express vasoactive intestinal peptide (VIP) and project to the central amygdala (CeA) and the oval nucleus of the bed nucleus of the stria terminalis (ovBNST). Together, these two regions comprise the central extended amygdala, a key network regulating adaptive responses to threats. We hypothesized that distinct DRNDA subpopulations exert diverging effects on sleep-wake regulation and that DRNVIP neurons play a pivotal role in coordinating activity between the CeA and ovBNST, thereby influencing risk assessment and defensive response. To test this hypothesis, we used a combination of in situ hybridization, immunochemistry, whole-brain mapping, electrophysiology, and cell-specific genetic tools in mice and non-human primates. Our findings reveal that DRNVIP neurons form a key DRNDA neuronal subset, uniquely positioned to regulate the central extended amygdala through a feedback loop. These neurons receive inputs from Protein Kinase C delta (PKC-{delta}) neurons in the ovBNST and CeA and send glutamate-releasing projections back to these regions, modulating PKC-{delta} neuron excitability. Selective ablation of DRNVIP neurons increases activity in both the BNST and CeA, disrupting active-phase sleep architecture and impairing risk assessment and defensive behaviors. Together, these findings suggest DRNVIP neurons control specific phases of sleep and orchestrate the central extended amygdalas role in risk assessment and defensive responses. HIGHLIGHTSO_LIDRNVIP neurons form a subset of DRNDA neurons in mice and non-human primates. C_LIO_LIDRNVIP receive inputs from Protein Kinase C delta (PKC-{delta}) neurons in the ovBNST and CeA and project back to both. C_LIO_LIBy releasing glutamate, DRNVIP neurons regulate PKC-{delta} neuron excitability in the ovBNST and CeA. C_LIO_LIAblating DRNVIP neurons increases BNST and CeA activity, disrupts active-phase sleep architecture, and impairs threat responses. C_LI IN BRIEFDRNVIP neurons, a key subset of DRNDA neurons in mice and primates, are strategically positioned to influence the central extended amygdala via feedback loops. They regulate PKC-{delta} neuron excitability in the ovBNST and CeA through glutamate release, with their ablation heightening activity in these regions and altering active-phase sleep architecture, risk assessment and defensive behaviors.

neuroscience↗

bioRxiv2024

Distinct neuronal processes in the ventromedial prefrontal cortex mediate changes in attention load and nicotine pro-cognitive effects

The prefrontal cortex (PFC) plays a key role in attention. In particular, neuronal activity in the ventromedial PFC (vmPFC) has been implicated in the preparatory attentional period that immediately precedes cue presentation. However, whether vmPFC neuronal activity during this preparatory period is also sensitive to changes in task demand and to the pro-cognitive effects of nicotine remained to be investigated. Here, we used in vivo electrophysiology to record vmPFC neuronal activity during two distinct manipulations: a task manipulation that increased task demand by reducing the cue stimulus duration (from 1s to 0.5s), and a pharmacological manipulation by administrating an acute nicotine injection (10 {micro}g/inj, i.v.) before the session. We found that increasing task demand decreased attentional performances and vmPFC precue neuronal activity, but had no effect on gamma oscillations. In contrast, nicotine injection increased attention and gamma oscillations, but almost abolished vmPFC phasic precue responses. Together, these findings indicate the existence of two distinct neuronal mechanisms operating at different timescales and suggests that allocation of attention could be achieved through multiple complementary neuronal mechanisms within the vmPFC.

neuroscience↗

bioRxiv2020

In vivo electrophysiological validation of DREADD-based inhibition of pallidal neurons in the non-human primate.

Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) are widely used in rodents to manipulate neuronal activity and establish causal links between structure and function. Their utilization in non-human primates (NHPs) is however limited and their efficacy still debated. Here, we tested DREADD expression in the NHP external globus pallidus (GPe) and electrophysiologically validated DREADD-based inhibition of GPe neurons in the anesthetized monkey.To do so, we performed intracerebral injections of viral construct expressing hM4Di receptor under a neuron-specific promoter into the GPe. Then, we recorded the neuronal activity in the DREADD-transduced (test condition) and DREADD-free (control condition) GPe of two anesthetized animals following local intra-GPe microinjection of clozapine-N-oxide (CNO). In total, 19 and 8 well-isolated and stable units were recorded in the DREADD-transduced and DREADD-free GPe, respectively. Overall, we found that almost half (9/19) of the units modulated their activity following CNO injection in DREADD-transduced GPe. Surprisingly, neuronal activity of the GPe units exhibited diverse patterns in timing and polarity (increase/decrease) of firing rate modulations during and after CNO injection. Nevertheless, decreases were exclusive and stronger after CNO injection. In contrast, only one unit modulated its activity after CNO injection in DREADD-free GPe. Moreover, post-mortem histochemical analysis revealed that hM4Di DREADDs were expressed at high level in the GPe neurons located in the vicinity of the viral construct injection sites. Our results therefore show in vivo DREADD-based inhibition of pallidal neurons in the NHP model and reinforce the view that DREADD technology can be effective in NHPs.

neuroscience↗

bioRxiv2019

Identification of distinct pathological signatures induced by patient-derived α-synuclein structures in non-human primates

AO_SCPLOWBSTRACTC_SCPLOWDopaminergic neuronal cell death, associated with intracellular -synuclein (-syn)-rich protein aggregates (termed Lewy bodies), is a well-established characteristic of Parkinsons disease. Much evidence, accumulated from multiple experimental models has suggested that -syn plays a role in PD pathogenesis, not only as a trigger of pathology but also as a mediator of disease progression through pathological spreading. Here we have used a machine learning-based approach to identify unique signatures of neurodegeneration in monkeys induced by distinct -syn pathogenic structures derived from PD patients. Unexpectedly, our results show that, in non-human primates, a small amount of singular -syn aggregates is as toxic as larger amyloid fibrils present in the LBs, thus reinforcing the need for preclinical research in this species. Furthermore, our results provide evidence supporting the true multifactorial nature of PD as multiple causes can induce similar outcome regarding dopaminergic neurodegeneration.

neuroscience↗