Publications by authors named "Fabiana Perocchi"

The mitochondrial calcium uniporter channel (MCUC) mediates mitochondrial calcium entry, regulating energy metabolism and cell death. Although several MCUC components have been identified, the molecular basis of mitochondrial calcium signaling networks and their remodeling upon changes in uniporter activity have not been assessed. Here, we map the MCUC interactome under resting conditions and upon chronic loss or gain of mitochondrial calcium uptake.

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Endothelial cells (ECs) are highly plastic, capable of differentiating into various cell types. Endothelial-to-mesenchymal transition (EndMT) is crucial during embryonic development and contributes substantially to vascular dysfunction in many cardiovascular diseases (CVDs). While targeting EndMT holds therapeutic promise, understanding its mechanisms and modulating its pathways remain challenging.

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Lipid composition is conserved within sub-cellular compartments to maintain cell function. Lipidomic analyses of liver, muscle, white and brown adipose tissue (BAT) mitochondria revealed substantial differences in their glycerophospholipid (GPL) and free cholesterol (FC) contents. The GPL to FC ratio was 50-fold higher in brown than white adipose tissue mitochondria.

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Article Synopsis
  • Brown adipose tissue (BAT) helps maintain body temperature in cold environments through a protein called UCP1, but the evolutionary origins of this process are not well understood.
  • Research indicates that marsupials have a nonthermogenic variant of UCP1, suggesting a different evolutionary pathway compared to eutherian mammals (like humans), which developed a thermogenic form of UCP1.
  • The findings imply that mammalian BAT thermogenesis evolved in two stages: an initial nonthermogenic stage in the common ancestor of therian mammals and later the development of thermogenic capabilities specifically in eutherians after their divergence from marsupials.
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Article Synopsis
  • * Research shows that neuroinflammatory lesions in mouse spinal cords lead to significant energy deficits in axons, impacting mitochondrial performance and enzyme levels in the tricarboxylic acid (TCA) cycle.
  • * Enhancing the expression of specific TCA cycle enzymes can help restore energy balance in affected neurons, indicating a potential therapeutic target for treating energy deficiencies in MS.
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Mitochondria are key bioenergetic organelles involved in many biosynthetic and signaling pathways. However, their differential contribution to specific functions of cells within complex tissues is difficult to dissect with current methods. The present protocol addresses this need by enabling the ex vivo immunocapture of cell-type-specific mitochondria directly from their tissue context through a MitoTag reporter mouse.

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Aging is a complex process characterized by several molecular and cellular imbalances. The composition and stability of the neuronal cytoskeleton is essential for the maintenance of homeostasis, especially in long neurites. Using human skin biopsies containing sensory axons from a cohort of healthy individuals, we investigate alterations in cytoskeletal content and sensory axon caliber during aging quantitative immunostainings.

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PTEN-induced kinase 1 (PINK1) is a short-lived protein required for the removal of damaged mitochondria through Parkin translocation and mitophagy. Because the short half-life of PINK1 limits its ability to be trafficked into neurites, local translation is required for this mitophagy pathway to be active far from the soma. The Pink1 transcript is associated and cotransported with neuronal mitochondria.

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Background And Purpose: Treatment of cardiac arrhythmia remains challenging due to severe side effects of common anti-arrhythmic drugs. We previously demonstrated that mitochondrial Ca uptake in cardiomyocytes represents a promising new candidate structure for safer drug therapy. However, druggable agonists of mitochondrial Ca uptake suitable for preclinical and clinical studies are still missing.

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The mitochondrial calcium uniporter (MCU ) is an essential protein of the inner mitochondrial membrane that mediates the uptake of calcium into mitochondria of virtually all mammalian tissues, regulating cell metabolism, signaling, and death. MCU-mediated calcium uptake has been shown to play a pathophysiological role in diverse human disease contexts, which qualifies this channel as a druggable target for therapeutic intervention.Here, we present a protocol to perform drug screens to identify effective and specific MCU-targeting inhibitors.

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Calcium dynamics control synaptic transmission. Calcium triggers synaptic vesicle fusion, determines release probability, modulates vesicle recycling, participates in long-term plasticity and regulates cellular metabolism. Mitochondria, the main source of cellular energy, serve as calcium signaling hubs.

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Human mitochondria are complex and highly dynamic biological systems, comprised of over a thousand parts and evolved to fully integrate into the specialized intracellular signaling networks and metabolic requirements of each cell and organ. Over the last two decades, several complementary, top-down computational and experimental approaches have been developed to identify, characterize and modulate the human mitochondrial system, demonstrating the power of integrating classical reductionist and discovery-driven analyses in order to de-orphanize hitherto unknown molecular components of mitochondrial machineries and pathways. To this goal, systematic, multiomics-based surveys of proteome composition, protein networks, and phenotype-to-pathway associations at the tissue, cell and organellar level have been largely exploited to predict the full complement of mitochondrial proteins and their functional interactions, therefore catalyzing data-driven hypotheses.

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The proteasome is the main proteolytic system for targeted protein degradation in the cell and is fine-tuned according to cellular needs. Here, we demonstrate that mitochondrial dysfunction and concomitant metabolic reprogramming of the tricarboxylic acid (TCA) cycle reduce the assembly and activity of the 26S proteasome. Both mitochondrial mutations in respiratory complex I and treatment with the anti-diabetic drug metformin impair 26S proteasome activity.

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Calcium (Ca) influx into mitochondria occurs through a Ca-selective uniporter channel, which regulates essential cellular processes in eukaryotic organisms. Previous evolutionary analyses of its pore-forming subunits MCU and EMRE, and gatekeeper MICU1, pinpointed an evolutionary paradox: the presence of MCU homologs in fungal species devoid of any other uniporter components and of mt-Ca uptake. Here, we trace the mt-Ca uniporter evolution across 1,156 fully-sequenced eukaryotes and show that animal and fungal MCUs represent two distinct paralogous subfamilies originating from an ancestral duplication.

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Background & Aims: Selective elimination of virus-infected hepatocytes occurs through virus-specific CD8 T cells recognizing peptide-loaded MHC molecules. Herein, we report that virus-infected hepatocytes are also selectively eliminated through a cell-autonomous mechanism.

Methods: We generated recombinant adenoviruses and genetically modified mouse models to identify the molecular mechanisms determining TNF-induced hepatocyte apoptosis in vivo and used in vivo bioluminescence imaging, immunohistochemistry, immunoblot analysis, RNAseq/proteome/phosphoproteome analyses, bioinformatic analyses, mitochondrial function tests.

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Mitochondria participate in metabolism and signaling. They adapt to the requirements of various cell types. Publicly available expression data permit to study expression dynamics of genes with mitochondrial function (mito-genes) in various cell types, conditions and organisms.

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Mitochondria vary in morphology and function in different tissues; however, little is known about their molecular diversity among cell types. Here we engineered MitoTag mice, which express a Cre recombinase-dependent green fluorescent protein targeted to the outer mitochondrial membrane, and developed an isolation approach to profile tagged mitochondria from defined cell types. We determined the mitochondrial proteome of the three major cerebellar cell types (Purkinje cells, granule cells and astrocytes) and identified hundreds of mitochondrial proteins that are differentially regulated.

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The development of fluorescence-based oxygen sensors coupled with microplate-based assays for quantitative bioenergetics analyses enables screening multiple experimental conditions at once with small biological material and in a timely manner. In this chapter, we outline detailed protocols and practical tips to design and perform controlled measurements of (a) respiratory and glycolytic metabolism of intact cells, (b) substrate-dependent respiration in permeabilized cells and isolated mitochondria, and (c) calcium-dependent regulation of mitochondrial bioenergetics with Seahorse XF Flux Analyzers.

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The mitochondrial calcium uniporter is a highly selective ion channel composed of species- and tissue-specific subunits. However, the functional role of each component still remains unclear. Here, we establish a synthetic biology approach to dissect the interdependence between the pore-forming subunit MCU and the calcium-sensing regulator MICU1.

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Activation and recruitment of thermogenic cells in human white adipose tissues ("browning") can counteract obesity and associated metabolic disorders. However, quantifying the effects of therapeutic interventions on browning remains enigmatic. Here, we devise a computational tool, named ProFAT (profiling of fat tissue types), for quantifying the thermogenic potential of heterogeneous fat biopsies based on prediction of white and brown adipocyte content from raw gene expression datasets.

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Mitochondria are pivotal organelles in calcium (Ca ) handling and signalling, constituting intracellular checkpoints for numerous processes that are vital for cell life. Alterations in mitochondrial Ca homeostasis have been linked to a variety of pathological conditions and are critical in the aetiology of several human diseases. Efforts have been taken to harness mitochondrial Ca transport mechanisms for therapeutic intervention, but pharmacological compounds that direct and selectively modulate mitochondrial Ca homeostasis are currently lacking.

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Reactive oxygen species (ROS) are generated by virus-infected cells; however, the physiological importance of ROS generated under these conditions is unclear. Here we found that the inflammation and cell death induced by exposure of mice or cells to sources of ROS were not altered in the absence of canonical ROS-sensing pathways or known cell-death pathways. ROS-induced cell-death signaling involved interactions among the cellular ROS sensor and antioxidant factor KEAP1, the phosphatase PGAM5 and the proapoptotic factor AIFM1.

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New Findings: What is the topic of this review? This paper overviews the links between Ca and Na signalling in various types of cells. What advances does it highlight? This paper highlights the general importance of ionic signalling and overviews the molecular mechanisms linking Na and Ca dynamics. In particular, the narrative focuses on the molecular physiology of plasmalemmal and mitochondrial Na -Ca exchangers and plasmalemmal transient receptor potential channels.

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The mitochondrial calcium uniporter complex is essential for calcium (Ca) uptake into mitochondria of all mammalian tissues, where it regulates bioenergetics, cell death, and Ca signal transduction. Despite its involvement in several human diseases, we currently lack pharmacological agents for targeting uniporter activity. Here we introduce a high-throughput assay that selects for human MCU-specific small-molecule modulators in primary drug screens.

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