ABSTRACT
Anxiety is a common mental disorder, and its prevalence has lately increased because of the COVID-19 pandemic. Unfortunately, the available anxiolytics are often ineffective, and most possess addictive potential. Thus, searching for novel compounds is essential. In our previous studies, we selected a multimodal compound, HBK-15, which showed a fast antidepressant-like effect in animal models of depression. HBK-15 demonstrated a high affinity for serotonin 5-HT1A receptors and moderate for 5-HT7, dopamine D2, and α1-adrenoceptors. Based on the receptor profile and preliminary studies, we aimed to investigate the anxiolytic potential of HBK-15 using the conditioned-response rat model of anxiety, i.e., the Vogel drinking test. We performed hot plate and free-drinking tests to exclude false positive results in the Vogel test. Using radioligand binding studies, we also investigated the affinity of the compound for the selected biological targets, which play a role in anxiety. Our experiments revealed that HBK-15 showed an anxiolytic-like effect in rats (5 mg/kg) without influencing the pain threshold or the amount of water consumed in the free-drinking test. Furthermore, the tested compound did not show a significant affinity for the selected biological targets, which suggests that its anxiolytic-like mechanism of action could be connected with the interaction with other receptors. This study indicates that multimodal compounds with a receptor profile similar to HBK-15 could be an attractive therapeutic option for patients with a generalized anxiety disorder. However, more studies are required to determine the exact mechanism of action of HBK-15 and its safety profile.
ABSTRACT
Progress in the study of Covid-19 disease in rodents has been hampered by the lack of angiotensin-converting enzyme 2 (ACE2; virus entry route to the target cell) affinities for the virus spike proteins across species. Therefore, we sought to determine whether a modified protocol of lipopolysaccharide (LPS)-induced acute respiratory distress syndrome in rats can mimic both cell signalling pathways as well as severe disease phenotypes of Covid-19 disease. Rats were injected via intratracheal (IT) instillation with either 15 mg/kg of LPS (model group) or saline (control group) before being killed after 3 days. A severe acute respiratory syndrome (SARS)-like effect was observed in the model group as demonstrated by the development of a "cytokine storm" (>2.7 fold increase in blood levels of IL-6, IL-17A, GM-CSF, and TNF-α), high blood ferritin, demonstrable coagulopathy, including elevated D-dimer (approximately 10-fold increase), PAI-1, PT, and APTT (p < 0.0001). In addition, LPS increased the expression of lung angiotensin II type I receptor (AT1R)-JAK-STAT axis (>4 fold increase). Chest imaging revealed bilateral small patchy opacities of the lungs. Severe lung injury was noted by the presence of both, alveolar collapse and haemorrhage, desquamation of epithelial cells in the airway lumen, infiltration of inflammatory cells (CD45+ leukocytes), widespread thickening of the interalveolar septa, and ultrastructural alterations similar to Covid-19. Thus, these findings demonstrate that IT injection of 15 mg/kg LPS into rats, induced an AT1R/JAK/STAT-mediated cytokine storm with resultant pneumonia and coagulopathy that was commensurate with moderate and severe Covid-19 disease noted in humans.
Subject(s)
Acute Lung Injury/etiology , Blood Coagulation Disorders/etiology , COVID-19/pathology , Cytokine Release Syndrome/etiology , Hemorrhage/etiology , Lipopolysaccharides/adverse effects , Lung Diseases/etiology , Receptor, Angiotensin, Type 1/metabolism , STAT Transcription Factors/metabolism , Signal Transduction , Acute Lung Injury/pathology , Animals , Blood Coagulation Disorders/pathology , COVID-19/etiology , Cytokine Release Syndrome/pathology , Disease Models, Animal , Hemorrhage/pathology , Janus Kinases , Lung Diseases/pathology , Male , Rats , Rats, WistarABSTRACT
Despite global vaccination efforts, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve and spread globally. Relatively high vaccination rates have been achieved in most regions of the United States and several countries worldwide. However, access to vaccines in low- and mid-income countries (LMICs) is still suboptimal. Second generation vaccines that are universally affordable and induce systemic and mucosal immunity are needed. Here we performed an extended safety and immunogenicity analysis of a second-generation SARS-CoV-2 vaccine consisting of a live Newcastle disease virus vector expressing a pre-fusion stabilized version of the spike protein (NDV-HXP-S) administered intranasally (IN), intramuscularly (IM), or IN followed by IM in Sprague Dawley rats. Local reactogenicity, systemic toxicity, and post-mortem histopathology were assessed after the vaccine administration, with no indication of severe local or systemic reactions. Immunogenicity studies showed that the three vaccination regimens tested elicited high antibody titers against the wild type SARS-CoV-2 spike protein and the NDV vector. Moreover, high antibody titers were induced against the spike of B.1.1.7 (alpha), B.1.351 (beta) and B.1.617.2 (delta) variants of concern (VOCs). Importantly, robust levels of serum antibodies with neutralizing activity against the authentic SARS-CoV-2 USA-WA1/2020 isolate were detected after the boost. Overall, our study expands the pre-clinical safety and immunogenicity characterization of NDV-HXP-S and reinforces previous findings in other animal models about its high immunogenicity. Clinical testing of this vaccination approach is ongoing in different countries including Thailand, Vietnam, Brazil and Mexico.
Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , Newcastle disease virus/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Administration, Intranasal , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/genetics , Immunogenicity, Vaccine , Injections, Intramuscular , Newcastle disease virus/immunology , Rats , Rats, Sprague-Dawley , SARS-CoV-2/genetics , Safety , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunologyABSTRACT
The recent outbreak of SARS CoV-2 has changed the global scenario of human lives/economy. A significant number of the non-survivors showed cardiac renal vasculature dysfunction. A 'cytokine storm' namely, interleukin IL6-IL1 receptors, i.e. IL6R-IL1R over-functioning was reported. Here, nigellidine, an indazole alkaloid and key component of Nigella sativa L. (NS) commonly known as black cumin seed was analysed for COVID-19 protein targeting and IL1R-IL6R inhibition through molecular docking study and biochemical study in experimental rat to evaluate antioxidative capacity. The NMR/X-ray crystallographic/electron microscopic structures of COVID-19 main protease (6LU7)/spike glycoprotein (6vsb)/NSP2 (QHD43415_2)/nucleocapsid (QHD43423), human IL1R (1itb)-IL6R (1pm9) from PDB were retrieved analysed for receptor-ligand interaction. Then, those structures were docked with nigellidine using AutoDock and PatchDock server. A brief comparison was made with nigellicine thymoquinone from N. sativa. Where nigellidine showed highest binding energy of -6.6 kcal/mol, ligand efficiency of -0.3 with COVID19 Nsp2 forming bonds with amino acid CYS240 present in binding pocket. Nigellidine showed strong interaction with main protease (BE: -6.38/LE: -0.29). Nigellidine showed affinity to IL1R (-6.23). The NS treated rat showed marked decline in ALP-SGPT-SGOT-malondialdehyde (MDA) than the basal levels. From the Western blot and activity analysis, it was observed that Nigellidine (sulphuryl group drug) showed no impact on phenol-catalysing ASTIV and steroid-catalysing oestrogen-sulphotransferase expressions and activities in liver tissue and thus has no influence in sulphation-mediated adverse metabolic processes. Conclusively, nigellidine has hepato-reno-protective/antioxidant-immunomodulatory/anti-inflammatory activities with inhibit potentials of COVID-19 proteins. Further validation is necessary.