Biology subjects

Charlie-Silva, I.

Publications and source records attributed to Charlie-Silva, I..

4 recordsLinked to original sources

bioRxiv2025

SARS-CoV-2 Spike Peptides Trigger Nociceptive Responses Through Spinal TLR4 Pathways

COVID-19 has affected over 700 million people worldwide, with a significant portion of the population experiencing severe pulmonary and circulatory complications, often accompanied by symptoms such as prostration and pain. Moreover, the manifestation of these symptoms and other COVID-19-related complications varies depending on viral mutations, particularly those occurring in the spike (S) protein of SARS-CoV-2. Therefore, the present study aimed to investigate the effects of three different S proteins on nociceptive threshold, as well as the spinal involvement of TLR4 and microglia in this process. Male C57BL/6 mice received intrathecal administration of three synthetic peptides (PSPD2001, PSPD2002 and PSPD2003) derived from the SARS-CoV-2 S protein or saline. Nociceptive threshold was assessed using the von Frey filament test before and after peptide administration. The spinal involvement of Toll-like receptor 4 (TLR4), microglia, p38 MAPK, and NF-{kappa}B was evaluated using specific antagonists and inhibitors. mRNA expression of TLR4 was assessed by RT-PCR, pro-inflammatory cytokine levels by ELISA, and microglial activation in the dorsal horn of the spinal cord was analyzed by immunofluorescence in wild-type, CX3CR1GFP{square}/{square}, and TLR4{square}/{square} mice. In addition, molecular dynamics analysis was performed to assess the temporal stability of the PSPD2003-TLR4 complex. Pharmacological data demonstrated that the peptides induced nociception involving TLR4, microglia, p38 MAPK, and NF-{kappa}B. Notably, PSPD2003 increased TLR4 mRNA expression and elevated TNF- and IL-6 levels in the spinal cord. PSPD2003 also enhanced microglial activation in the spinal cord, which was abolished in TLR4{square}/{square} mice. Molecular dynamics analysis results robustly demonstrate that PSPD2003 forms a stable and functionally relevant complex with TLR4. These findings suggest that SARS-CoV-2 S protein-derived peptides contribute to pain during COVID-19 infection, with spinal TLR4 and microglia playing key roles in this process.

pharmacology and toxicology↗

bioRxiv2021

Immunization with SARS-CoV-2 nucleocapsid protein triggers a pulmonary immune response in rats

The SARS-CoV-2 pandemic have been affecting millions of people worldwide, since the beginning of 2020. COVID-19 can cause a wide range of clinical symptoms, which varies from asymptomatic presentation to severe respiratory insufficiency, exacerbation of immune response, disseminated microthrombosis and multiple organ failure, which may lead to dead. Due to the rapid spread of SARS-CoV-2, the development of vaccines to minimize COVID-19 severity in the world population is imperious. One of the employed techniques to produce vaccines against emerging viruses is the synthesis of recombinant proteins, which can be used as immunizing agents. Based on the exposed, the aim of the present study was to verify the systemic and immunological effects of IM administration of recombinant Nucleocapsid protein (NP), derived from SARS-CoV-2 and produced by this research group, in 2 different strains of rats (Rattus norvegicus); Wistar and Lewis. For this purpose, experimental animals received 4 injections of NP, once a week, and were submitted to biochemical and histological analysis. Our results showed that NP inoculations were safe for the animals, which presented no clinical symptoms of worrying side effects, nor laboratorial alterations in the main biochemical and histological parameters, suggesting the absence of toxicity induced by NP. Moreover, NP injections successfully triggered the production of specific anti-SARS-CoV-2 IgG antibodies by both Wistar and Lewis rats, showing the sensitization to have been well sufficient for the immunization of these strains of rats. Additionally, we observed the local lung activation of the Bronchus-Associated Lymphoid Tissue (BALT) of rats in the NP groups, suggesting that NP elicits specific lung immune response. Although pre-clinical and clinical studies are still required, our data support the recombinant NP produced by this research group as a potential immunizing agent for massive vaccination, and may represent advantages upon other recombinant proteins, since it seems to induce specific pulmonary protection.

immunology↗

bioRxiv2021

CAN CARBON NANOFIBERS AFFECT ANUROFAUNA? STUDY INVOLVING NEOTROPICAL Physalaemus cuvieri (Fitzinger, 1826) TADPOLES

Although carbon nanotubes (CNTs) toxicity in different experimental systems (in vivo and in vitro) is known, little is known about the toxic effects of carbon nanofibers (CNFs) on aquatic vertebrates. We herein investigated the potential impact of CNFs (1 and 10 mg/L) by using Physalaemus cuvieri tadpoles as experimental model. CNFs were able to induce nutritional deficit in animals after 48-h exposure to them, and this finding was inferred by reductions observed in body concentrations of total soluble carbohydrates, total proteins, and triglycerides. The increased production of hydrogen peroxide, reactive oxygen species and thiobarbituric acid reactive substances in tadpoles exposed to CNFs has suggested REDOX homeostasis change into oxidative stress. This process was correlated to the largest number of apoptotic and necrotic cells in the blood of these animals. On the other hand, the increased superoxide dismutase and catalase activity has suggested that the antioxidant system of animals exposed to CNFs was not enough to maintain REDOX balance. In addition, CNFs induced increase in acetylcholinesterase and butyrylcholinesterase activity, as well as changes in the number of neuromats evaluated on body surface (which is indicative of the neurotoxic effect of nanomaterials on the assessed model system). To the best of our knowledge, this is the first report on the impact of CNFs on amphibians; therefore, it broadened our understanding about ecotoxicological risks associated with their dispersion in freshwater ecosystems and possible contribution to the decline in the populations of anurofauna species.

zoology↗

bioRxiv2021

An insight into neurotoxic and toxicity of spike fragments SARS-CoV-2 by exposure environment: A threat to aquatic health?

The Spike protein (S protein) is a critical component in the infection of the new coronavirus (SARS-CoV-2). The objective of this work was to evaluate whether peptides from S protein could cause negative impact in the aquatic animals. The aquatic toxicity of SARS-CoV-2 spike protein peptides derivatives has been evaluated in tadpoles (n = 50 tadpoles / 5 replicates of 10 animals) from species Physalaemus cuvieri (Leptodactylidae). After synthesis, purification, and characterization of peptides (PSDP2001, PSDP2002, PSDP2003) an aquatic contamination has been simulatedwith these peptides during 24 hours of exposure in two concentrations (100 and 500 ng/mL). The control group ("C") was composed of tadpoles kept in polyethylene containers containing de-chlorinated water. Oxidative stress, antioxidant biomarkers and neurotoxicity activity were assessed. In both concentrations, PSPD2002 and PSPD2003 increased catalase and superoxide dismutase antioxidants enzymes activities, as well as oxidative stress (nitrite levels, hydrogen peroxide and reactive oxygen species). All three peptides also increased acetylcholinesterase activity in the highest concentration. These peptides showed molecular interactions in silico with acetylcholinesterase and antioxidant enzymes. Aquatic particle contamination of SARS-CoV-2 has neurotoxics effects in P. cuvieri tadpoles. These findings indicate that the COVID-19 can constitute environmental impact or biological damage potential. HIGHLIGHTSO_LISARS-CoV-2 spike protein peptides (PSDP) were synthesized, purified, and characterized by solid phase peptide synthesis. C_LIO_LIPSDP peptides promoted REDOX imbalance and acute neurotoxicity in tadpoles (Physalaemus cuvieri) C_LIO_LIIn silico studies have shown interactionsbetween peptides and acetylcholinesterase and antioxidant enzymes C_LIO_LIAquatic particle contamination of SARS-CoV-2 can constitute additional environmental damage C_LI GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/425914v1_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@1b86f96org.highwire.dtl.DTLVardef@1a6225corg.highwire.dtl.DTLVardef@19d953org.highwire.dtl.DTLVardef@10af7ff_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗