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Biology subjects

Bernardi, M.

Publications and source records attributed to Bernardi, M..

5 recordsLinked to original sources

LINC00205 acts as a multivalent scaffold promoting FUSP525L recruitment in Amyotrophic Lateral Sclerosis stress granules

Stress granules (SG) are dynamic, membrane-less ribonucleoprotein assemblies that orchestrate cellular stress responses and rapidly disassemble upon stress relief. In Amyotrophic Lateral Sclerosis (ALS), mutations in RNA-binding proteins such as Fused in Sarcoma (FUS) impair SG dynamics, promoting the formation of aberrant and persistent granules. Although long non-coding RNAs (lncRNAs) are emerging as regulators of ribonucleoprotein organization, their mechanistic role in SG architecture and pathological remodeling remains largely unexplored. Here, we identify LINC00205 as a critical RNA regulator of pathological SG dynamics in FUSP525L-associated ALS. Using Neuroblastoma cells and human iPSC-derived Motor Neurons (MN), we show that LINC00205 is enriched in SG upon oxidative stress and directly interacts with mutant FUSP525L. Knock-out of LINC00205 selectively reduces the formation of FUSP525L-containing SG and restores physiological SG disassembly kinetics, without affecting normal SG or FUS expression levels. Mechanistically, LINC00205 acts as a multivalent RNA scaffold, directly binding mRNAs specifically enriched in pathological SG, such as PLCXD3 and PIK3CA, as well as the RNA helicase DHX36, which is preferentially associated with FUSP525L-containing SG. We demonstrate that LINC00205 promotes their specific recruitment into pathological SG, thereby contributing to the aberrant features of these assemblies. Together, our findings uncover an active lncRNA-driven mechanism that shapes the molecular composition of aberrant ALS-related SG and regulates their persistence, establishing lncRNAs as key organizers of RNA-protein assemblies under stress and providing a conceptual framework for modulating pathological condensates.

molecular biology↗

New insights into the extinction and recovery of marine vertebrates across the Permian-Triassic mass extinction event in the Dolomites, Southern Alps, Italy

The impact of the Permian-Triassic mass extinction on marine vertebrates is poorly known due to their scarce fossil record. Here, we report Acrodus sp. [Chondrichthyes], Bobasatrania aff. ladina [Osteichthyes] and an indeterminate actinopterygian from the Changhsingian Bellerophon Formation, and a saurosphargid reptile from the lower Spathian Val Badia Member of the Werfen Formation in the Dolomites, Italy. The saurosphargid is represented by a single vertebra, whose relatively tall neural spine indicates that it might belong to a new species. This is one of the oldest Sauropterygomorpha records worldwide and the first unambiguous occurrence of Saurosphargidae in the western Paleo-Tethys during the Early Triassic. These new findings suggest fishes were more diverse in this paleo-tropical shallow shelf community of the western Paleo-Tethys in the latest Permian than during the Early Triassic. The evolution of the new apex predator niche (Saurosphargidae) relatively shortly after the mass extinction event coincides with the reappearance of predatory cephalopods and precedes the full ecological and taxonomic recovery of benthic groups in the Dolomites community. This contrasts with previous hypotheses about the delayed recovery of higher trophic groups. Furthermore, we dated a surface sample with actinopterygian scales found at a Permian-Triassic boundary outcrop. The U-Pb indicates 248+/-1 Ma as a maximum depositional age, and radiolarian biostratigraphy indicates an Anisian age. This suggests age assignments to surface samples require caution. U-Pb dating further reveals an age discrepancy in the scales and the host rock, likely due to 206Pb enrichment in scales during diagenesis.

paleontology↗

Phasor Identifier: A Cloud-based Analysis of Phasor-FLIM Data on Python Notebooks

This study aims at creating an accessible notebook tool for the versatile analysis of phasor Fluorescence Lifetime Imaging Microscopy (FLIM) data collected from various samples (e.g. cuvette, cells, tissues) and in various input file formats. The presented strategy facilitates morphological segmentations and diverse mask imports. Results derived from three compelling case studies involving cellular metabolism, nanoscale drug encapsulation (doxorubicin), and the impact of pH and metabolic cleavage on small fluorescent drugs (irinotecan), showcase extensive analysis capabilities. The notebook-centered approach accelerates phasor-FLIM data analysis via external servers, supporting multi-scale research and avoiding the need for GPUs, RAM, and disk space.

biophysics↗

Direct optical nanoscopy unveils signatures of cytokine-induced β-cell structural and functional stress

Here we exploit a combination of advanced optical-microscopy tools and fluorescently-labeled molecular targets in rat Insulinoma 1E {beta}-cells exposed to proinflammatory cytokines. Expansion microscopy (ExM) is used to achieve the spatial resolution (~50 nm) needed to analyze the structural features of key subcellular targets, i.e. insulin secretory granules (ISGs), microtubules, actin filaments, and mitochondria; time-lapse live-cell microscopy, on the other hand, provides complementary information on key dynamic and metabolic subcellular parameters. It is found that 24-hours exposure to proinflammatory cytokines induces a neat decrease in the number of ISGs and alteration in the dynamics of the residual pool, marked depolymerization of microtubules, change in mitochondrial morphology and metabolic activity, and decreased cell responsiveness to glucose stimulation. This is accompanied by clear signatures of the production of reactive oxygen species. Reported results provide direct evidence that proinflammatory cytokines act as potent stimulators of insulin secretion and, concomitantly, as cell stressors.

biophysics↗

Environmental enrichment reverses memory impairment in B3-ARKO mice

Norepinephrine plays an important role in modulating the processes of memory consolidation and evocation through its beta-adrenergic receptors (Adr{beta}), which are expressed in the hippocampus and amygdala. Several studies have shown that all three subtypes of Adr{beta} ({beta}1, {beta}2 and {beta}3) play an important role in cognition. Environmental enrichment (EE), a technique initially used to decrease the stress of animals held in captive environments, has also been shown to produce cognitive benefits in both healthy and sick animals. In this study, we hypothesized that EE would reverse the memory impairment induced by the absence or Adr{beta}3. To test this, 21- and 86-day-old Adr{beta}3KO mice were exposed to an EE protocol for 8 weeks. The study showed that the EE protocol is able to correct the memory impairment when applied to Adr{beta}3KO animals immediately after weaning but has no effect when applied to adult animals. We also found that aging worsens the memory of Adr{beta}3KO mice. Our results suggest that a richer and more diverse environment helps to correct memory impairment in Adr{beta}3KO animals. They also reinforce the idea that noradrenergic signaling is involved in the cognitive impairment observed late in life, as aging led to a worsening in the memory of the Adr{beta}3KO animals that was not corrected by the environmental enrichment protocol.

neuroscience↗