Biology subjects

Foguel, D.

Publications and source records attributed to Foguel, D..

6 recordsLinked to original sources

bioRxiv2025

Neutrophil Extracellular Traps Mediate In Vitro and In Vivo Degradation of α-Synuclein Amyloid Fibrils

Neutrophil extracellular traps (NETs) are chromatin-derived structures decorated with neutrophil enzymes such as elastase and myeloperoxidase. Our group has previously demonstrated that amyloid fibrils (AFs), regardless of their protein composition, induce NET release in vitro in human neutrophils through a process dependent on reactive oxygen species (ROS) generation by NADPH oxidase 2 (NOX-2). Moreover, the proteases embedded in NETs were shown to degrade AFs into smaller, potentially toxic species. The present study aimed to determine whether amyloid fibrils composed of -synuclein (SF) can induce NET formation in vivo and to investigate the role of NETs in modulating amyloid-associated pathology. To this end, we employed gp91phox knockout (KO) mice, which lack NOX-2 activity and are therefore unable to release NETs. SF was instilled into the lungs of both WT and KO mice (males and females), leveraging the lungs robust immune cell recruitment - particularly of neutrophils-as a model system. Eight hours after SF instillation, both WT and KO animals exhibited marked neutrophil infiltration in the lungs causing inflammation. However, NET formation-evidenced by the presence of citrullinated histones and myeloperoxidase - was detected only in WT mice. Interestingly, while Congo red-positive amyloid-like structures persisted in the lungs of KO mice, they were absent in the lungs of WT animals, suggesting that NET-associated proteases facilitate the clearance of AFs from lung tissue. Lung function was assessed by measuring elastance and resistance. Our data showed that, while AFs were still present in the lungs of both WT and KO mice, elastance was impaired. As AFs were cleared from the lungs of WT mice, lung function recovered. In contrast, KO animals, in which AFs persisted, continued to exhibit compromised elastance. Together, our findings demonstrate that AFs impair lung function, and that NETs, induced in response to these fibrils, promote their degradation and thereby protect lung tissue from further damage.

biochemistry↗

bioRxiv2023

Alpha-synuclein oligomers activate nuclear factor of activated T-cells (NFAT) modulating apoptosis and synaptic homeostasis

Soluble oligomeric forms of alpha-synuclein (aSyn-O) are believed to be one of the main toxic species in Parkinsons disease (PD) leading to degeneration. aSyn-O can induce Ca2+ influx, over activating downstream pathways leading to PD phenotype. Calcineurin (CN), a phosphatase regulated by Ca2+ levels, activates NFAT transcription factors that are involved in the regulation of neuronal plasticity, growth and survival. Here, we investigate NFATs role in neuronal degeneration induced by aSyn-O. aSyn-O are toxic to neurons leading to cell death, loss of neuron ramification and reduction of synaptic proteins which are reversed by CN inhibition with ciclosporin-A or VIVIT, a NFAT specific inhibitor. aSyn-O induce NFAT nuclear translocation and transactivation. We found that aSyn-O modulates the gene involved in the maintenance of synapses, synapsin 1 (Syn 1). Syn1 mRNA and protein and synaptic puncta are drastically reduced in cells treated with aSyn-O which are reversed by NFAT inhibition. For the first time a direct role of NFAT in aSyn-O-induced toxicity and Syn1 gene regulation was demonstrated, enlarging our understanding of the pathways underpinnings synucleinopathies.

neuroscience↗

bioRxiv2021

Paving the way towards understanding the inflammatory pathways triggered by giant viruses in mammalian cells: effect of mimivirus-cell interactions on IκBα degradation

Even after two decades since the identification of the first giant virus, the Acanthamoeba polyphaga mimivirus (APMV), it still elude scientists. Their gigantic size and genome are unique in the whole virosphere, and many aspects of their biology are still unknown, including their possible hosts. They are cultivated in laboratories using Acanthamoeba cells as hosts, but little is known about the infectivity of these giant viruses in vertebrate cells. However, there is evidence of the possible involvement of APMV in pneumonia and activation of inflammatory pathways. Among the hundreds of prospected giant viruses members is Tupanvirus, isolated in Brazil. Its particles have a characteristically large size varying between 1.2 to 2 m and are covered by fibrils. In the present work, we aim to study the consequences of the incubation of APMV and Tupanvirus with mammalian cells. These cells express Toll-like receptors (TLR) that are capable of recognizing lipopolysaccharides, favoring the internalization of the antigen and activation of the inflammatory system. We used a lineage of human lung adenocarcinoma cells (A549) to evaluate possible effects of TLR activation by the giant viruses and if we could detect the probable cause of the said giant-virus dependent pneumonia. Our results show that APMV and Tupanvirus (TPV) activate cellular receptors related to the Toll-like 4 type-induced inflammatory response and that the A549 cells are capable of internalizing the latter virus. Therefore, this study brings new insights into the possible interactions established between mimiviruses (here represented by APMV and Tupanvirus) and members of the innate cellular immune response.

microbiology↗

bioRxiv2021

Peptides derived from gp43, the most antigenic protein from Paracoccidioides brasiliensis, form amyloid fibrils in vitro: implications for vaccine development

Fungal infection is an important public health problem afflicting more than a billion people worldwide. Mycoses are especially important in Latin America, and in Brazil in particular. Paracoccidioides is the genus of fungi responsible for paracoccidioidomycosis comprising two species, P. brasiliensis and P. lutzii. The lungs are the primary infection site, but oral mucosa and airways can also be affected. The glycoprotein gp43 is involved in fungi adhesion to epithelial cells and is the most studied protein of P. brasiliensis. Seminal work identified a specific stretch of 15 amino acids that spans the region 181-195 (called P10) as an important epitope of gp43, being recognized by T lymphocytes in peripheral blood mononuclear cells of mice and humans and is envisioned as a potential vaccine component. Here, we show by using thioflavin T (ThT), transmission electron microscopy and other methods that synthetic P10 forms typical amyloid aggregates in solution in very short times, a property that could hamper vaccine development. In silico, aggregation analysis reveals several aggregation-prone regions (APR) in the P10 sequence that are capable of forming amyloid cores with steric zipper architecture. Seeds of P10 obtained by fibril mechanical fragmentation were able to induce the aggregation of P4 but not P23, as evidenced by ThT binding and mass spectrometry. These two peptides, also derived from gp43, are potent modulators of local and systemic inflammation. In-silico proteolysis studies with gp43 revealed that aggregation-prone, P10-like peptides could be generated by the action of several proteases such as proteinase K, trypsin and pepsin, which suggests that P10 could be formed upon gp43 digestion in a physiological condition. Considering our data in the context of a potential vaccine development, we redesigned the sequence of the P10 peptide, maintaining the antigenic region (HTLAIR), but drastically reducing its aggregation propensity.

biochemistry↗

bioRxiv2021

Oligomeric α-Synuclein induces skin degeneration in a reconstructed human epidermis model

Cell senescence may promote epidermal inflammation and degeneration, termed as inflammaging, which is accompanied by keratinocyte loss, resulting in fine lines of wrinkles. Recent findings showed that healthy elderly skin expresses age- and neuron-related amyloidogenic proteins, such as tau, {beta}-Amyloid34, and -synuclein (-Syn), typically found in patients with neurodegenerative diseases. These proteins form toxic aggregates that trigger inflammatory signals. Herein, we investigated the impact of oligomeric -Syn (O-Syn) on the neurosphere (NP) and the reconstructed human epidermis (RHE) 3D models. First, we found the expression of -Syn, {beta}-Amyloid, and amyloid precursor protein (APP) in the RHE. Second, we challenged the RHE and NP with O-Syn, which decreased RHE regeneration, measured by the percentage of cell proliferation and thickness of the stratum basale, but did not affect NP neurite outgrowth. O-Syn did not decrease the number of human neonatal epidermal keratinocytes (HEKn) but, as seen for the RHE, it also decreased the proliferation of HEKn. We confirmed that the oligomeric, and not the monomeric -Syn species, accounted for the proliferation-decreasing effect. O-Syn also increased the NF-kB nuclear translocation in HEKn analyzed by nucleus/cytoplasm NF-{kappa}B fluorescence intensity. In addition, O-Syn triggered inflammation in the RHE, by increasing the mRNA levels of IL-1{beta} and tumor necrosis factor-alpha (TNF-), and the release of TNF- in a time-dependent manner. These findings show that O-Syn does not affect neurite outgrowth but induces a decrease in keratinocyte proliferation along with epidermal inflammation. With our tridimensional models, we demonstrated that the neurodegenerative protein O-Syn also degenerates the epidermis, drawing attention to the need of target-based screening to prevent and treat the effects of skin aging.

neuroscience↗

bioRxiv2019

Cerebral dopamine neurotrophic factor (CDNF) reduces myocardial ischemia/reperfusion injuries by the activation of PI3K-AKT via KDEL-receptor binding

CDNF (Cerebral Dopamine Neurotrophic Factor) belongs to a new family of NF, which presents several beneficial activities beyond the brain. Little is known about CDNF in the cardiac context. Herein we investigate CDNF effects in cardiomyocytes under endoplasmic reticulum (ER)-stress and in whole rat hearts subjected to ischemia/reperfusion (I/R). We showed that CDNF is secreted by cardiomyocytes stressed by thapsigargin and by isolated hearts subjected to I/R. CDNF protects human and mouse cardiomyocytes against ER-stress by restoring the calcium transient, and isolated heart against I/R injuries by reducing the infarct area and avoiding mitochondrial impairment. This protection is abrogated by wortmannin (PI3K-inhibitor) or by heptapeptides containing KDEL sequence, which block KDEL-receptor. These data suggest that CDNF induces cardioprotection via KDEL receptor binding and PI3K/AKT activation. This is the first study to propose CDNF as a cardiomyokine and to unravel the receptor and signaling pathway for this interesting family of NF.

physiology↗