Docking Prediction of Levodopa in the Receptor Binding Domain of Spike Protein of SARS-CoV-2.

Levodopa is a prodrug that is converted into dopamine, which replenishes the deficient dopamine in the brain of patients suffering from Parkinsonism. We hypothesize that levodopa may interact with the receptor binding domain of the SARS-CoV-2 and may act as a physical impediment to the viral entry into the host cell.

'Targeting the feast of a sleeping beast': Nutrient and mineral dependencies of encysted Acanthamoeba castellanii.

Acanthamoeba spp. cause a corneal infection, Acanthamoeba keratitis (AK), and a cerebral infection, granulomatous amoebic encephalitis (GAE). Though aggressive chemotherapy has been able to kill the active trophozoite form of Acanthamoeba, the encysted form of this parasite has remained problematic to resist physiological concentrations of drugs. The emergence of encysted amoeba into active trophozoite form poses a challenge to eradicate this parasite. Acanthamoeba trophozoites have active metabolic machinery that furnishes energy in the form of ATPs by subjecting carbohydrates and lipids to undergo pathways including glycolysis and beta-oxidation of free fatty acids, respectively. However, very little is known about the metabolic preferences and dependencies of an encysted trophozoite on minerals or potential nutrients that it consumes to live in an encysted state. Here, we investigate the metabolic and nutrient preferences of the encysted trophozoite of Acanthamoeba castellanii and the possibility to target them by drugs that act on calcium ion dependencies of the encysted amoeba. The experimental assays, immunostaining coupled with bioinformatics tools show that the encysted Acanthamoeba uses diverse nutrient pathways to obtain energy in the quiescent encysted state. These findings highlight potential pathways that can be targeted in eradicating amoebae cysts successfully.

Ocular COVID-19: Eyes as a Reservoir to Conceal and Spread SARSCoV- 2.

Ocular tissues can serve as a reservoir for the SARS-CoV-2 virus which can not only cause conjunctivitis but also serve as a source of infection transmission to others. Additionally, the eye and its tear drainage apparatus can track the SARS-CoV-2 from the eye into the respiratory tract of the patient. The potential ocular presence of the SARS-CoV-2 in the eye of a patient can target ACE2 receptors in the endothelium of the conjunctival vessels and use the lacrimal sac a potential space to evade immune detection and clinical isolation. The recently reported case of COVID-19 after the acquisition of SARS-CoV-2 from a COVID-19 patient should alert the healthcare professionals dealing with COVID-19 patients that wearing masks alone cannot guarantee protection against infection transmission. Further studies, like isolation of SARS-CoV-2 from the eyes of patients with COVID-19, are needed to identify the eyes as a potential source of SARS-CoV-2 infection transmission.

Docking Prediction of Amantadine in the Receptor Binding Domain of Spike Protein of SARS-CoV-2.

Amantadine has recently been shown to improve patients with COVID-19. In addition to its known mechanism of actions, we performed docking prediction of this drug on the receptor-binding domain of severe acute respiratory syndrome coronavirus 2, SARS-CoV-2. We hypothesize that such interaction may possibly have contributed a role in the clinical improvements reported.

First Reports of Effects of Insulin, Human-like Insulin Receptors and Adapter Proteins in Acanthamoeba castellanii.

The insulin receptor (IR) and insulin-like growth factor 1 receptor (IGF1-R) play key roles in growth, regulation of nutrient metabolism and carbohydrate homeostasis. Insulin-like molecules in prokaryotes and other early life have been reported. However, an account of metabolic effects of insulin, transcriptomic evidence of expression of glucose transporting channels (GLUT) and homology modelling of IR and IGF1-R like proteins in unicellular life-forms have yet to be established. Acanthamoeba spp. has existed for about 2 billion years and is one of the earliest mitochondriate unicellular eukaryotic cells on Earth. Despite Acanthamoeba spp. being grown in a medium called peptone-yeast-glucose (PYG) for over 50 years, the mechanism and regulation of glucose uptake by IR or IGF1-R molecules in this microbe has not yet been reported. Several methods were utilized to validate the effects of insulin on trophozoites of A. castellanii, including: growth assays with insulin, estimation of glucose and potassium (K+) entry into the cell, and histology showing anabolic effects on proteins. Bioinformatic computational tools and homology modeling demonstrated the involvement of IR like proteins, GLUT, and adapter proteins in mediating the IR cascade. Growth assays showed proliferative effects in a dose range of 2.98-5.97 µmol/mL of insulin. After insulin exposure, A. castellanii trophozoites displayed enhanced Periodic acid-Sciff (PAS) staining. Amino acid sequence similarities and homology modelling revealed ACA1_163470 in Acanthamoeba spp. to be a homolog of human-IR. Acanthamoeba protein ACA1_336150 shares similarities with IGF1-R. Additionally, some proteins like ACA1_060920 have attributes of GLUT like channels on homology modelling and show similarity with human GLUT. Knowledge of IR and insulin effects in Acanthamoeba spp. contributes to its biology and advances current understanding behind the evolution of IR and IGF1-R signalling cascade.

Elucidation of cellular targets and exploitation of the receptor-binding domain of SARS-CoV-2 for vaccine and monoclonal antibody synthesis.

The pandemic caused by novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) has resulted in over 452 822 deaths in the first 20 days of June 2020 due to the coronavirus virus disease 2019 (COVID-19). The SARS-CoV-2 uses the host angiotensin-converting enzyme 2 (ACE2) receptor to gain entry inside the human cells where it replicates by using the cell protein synthesis mechanisms. The knowledge of the tissue distribution of ACE2 in human organs is therefore important to predict the clinical course of the COVID-19. Also important is the understanding of the viral receptor-binding domain (RBD), a region within the spike (S) proteins, that enables the entry of the virus into the host cells to synthesize vaccine and monoclonal antibodies (mAbs). We performed an exhaustive search of human protein databases to establish the tissues that express ACE2 and performed an in-depth analysis like sequence alignments and homology modeling of the spike protein (S) of the SARS-CoV-2 to identify antigenic regions in the RBD that can be exploited to synthesize vaccine and mAbs. Our results show that ACE2 is widely expressed in human organs that may explain the pulmonary, systemic, and neurological deficits seen in COVID-19 patients. We show that though the S protein of the SARS-CoV-2 is a homolog of S protein of SARS-CoV-1, it has regions of dissimilarities in the RBD and transmembrane segments. We show peptide sequences in the RBD of SARS-CoV-2 that can bind to the major histocompatibility complex alleles and serve as effective epitopes for vaccine and mAbs synthesis.

Future Oncotargets: Targeting Overexpressed Conserved Protein Targets in Androgen Independent Prostate Cancer Cell Lines.

BACKGROUND: Targeting evolutionarily conserved proteins in malignant cells and the adapter proteins involved in signalling that generates from such proteins may play a cardinal role in the selection of anti-cancer drugs. Drugs targeting these proteins could be of importance in developing anti-cancer drugs. OBJECTIVES: We inferred that drugs like loperamide and promethazine that act as antagonists of proteins conserved in cancer cells like voltage-gated Calcium channels (Cav), Calmodulin (CaM) and drug efflux (ABCB1) pump may have the potential to be re-purposed as an anti-cancer agent in Prostate Cancer (PCa). METHODS: Growth and cytotoxic assays were performed by selecting loperamide and promethazine to target Cav, CaM and drug efflux (ABCB1) pumps to elucidate their effects on androgen-independent PC3 and DU145 PCa cell lines. RESULT: We show that loperamide and promethazine in doses of 80-100µg/ml exert oncocidal effects when tested in DU145 and PC3 cell lines. Diphenhydramine, which shares its targets with promethazine, except the CaM, failed to exhibit oncocidal effects. CONCLUSION: Anti-cancer effects can be of significance if structural analogues of loperamide and promethazine that specifically target Cav, CaM and ABCB1 drug efflux pumps can be synthesized, or these two drugs could be re-purposed after human trials in PCa.

Evidence of the COVID-19 Virus Targeting the CNS: Tissue Distribution, Host-Virus Interaction, and Proposed Neurotropic Mechanisms.

The recent outbreak of coronavirus infectious disease 2019 (COVID-19) has gripped the world with apprehension and has evoked a scare of epic proportion regarding its potential to spread and infect humans worldwide. As we are in the midst of an ongoing pandemic of COVID-19, scientists are struggling to understand how it resembles and differs from the severe acute respiratory syndrome coronavirus (SARS-CoV) at the genomic and transcriptomic level. In a short time following the outbreak, it has been shown that, similar to SARS-CoV, COVID-19 virus exploits the angiotensin-converting enzyme 2 (ACE2) receptor to gain entry inside the cells. This finding raises the curiosity of investigating the expression of ACE2 in neurological tissue and determining the possible contribution of neurological tissue damage to the morbidity and mortality caused by COIVD-19. Here, we investigate the density of the expression levels of ACE2 in the CNS, the host-virus interaction and relate it to the pathogenesis and complications seen in the recent cases resulting from the COVID-19 outbreak. Also, we debate the need for a model for staging COVID-19 based on neurological tissue involvement.

Targeting CNS Related Protist Pathogens: Calcium Ion Dependency in the Brain-Eating Amoebae.

Of the free-living amoebae (FLA) Naegleria fowleri, Balamuthia mandrillaris, and Acanthamoeba spp. are known to cause encephalitis. Coined with the term "brain-eating amoebae" (BEA), infection of the central nervous system with FLA has a high mortality rate. A combination of diagnostic delay, lack of new drug development, and incomplete understanding of the dependencies of FLA have resulted in the failure of introducing safer and effective drugs. We inferred that being a shape-changing entity the FLA should have a dependency on calcium (Ca2+) ions that could be targeted to cripple the pathogenicity of the FLA. We used genomic, transcriptomic, and proteomic information available on FLA in online databases to evidence the presence of various Ca2+ion influx regulating channels, reviewing adapter proteins at first and then targeting human-like voltage-gated Ca2+ channels with nifedipine and verapamil that are used clinically for noninfectious diseases to see their effect in trophozoites of Acanthamoeba spp. in particular.

Neuroleptic Drug Targets a Brain-Eating Amoeba: Effects of Promethazine on Neurotropic Acanthamoeba castellanii.

Acanthamoeba spp. has recently been reported to express diverse group of ion channels and receptors that are expressed by human cells which bind drugs that are used in noninfectious diseases. Bioinformatics computational tools, growth assays, and 3D structural modeling have enabled the discovery of primitive muscarinic receptors, voltage-gated calcium channels, and ion transport pumps such as Na-K ATPase in this protist pathogen. The significance of the reported receptors and ion channels in the biology of Acanthamoeba is yet to be determined. We selected promethazine, which is a known antagonist of proteins like dopaminergic, histaminergic, muscarinic receptors, and calmodulin, to determine its effects on the growth and proliferation of trophozoites and cysts of Acanthamoeba spp. In order to elucidate the receptors involved in the effects produced by promethazine, we also performed individual experiments on Acanthamoeba trophozoites and cysts in the presence of the agonist of the above-mentioned receptors. Our results show that promethazine in the range of 60-100 µg/mL proved to be amoebicidal for Acanthamoeba trophozoites and at slightly higher doses ranging around 125-250 µg/mL also showed partial cysticidal effects. We also show the evidence of homology between the human targets of promethazine and similar targets in Acanthamoeba by the use of bioinformatic computational tools and 3D modeling. Promethazine and its structural analogs, because of being FDA-approved, have a wider margin of safety that can be tested as potential anti- Acanthamoeba agents in diseases like keratitis and encephalitis caused by this protist pathogen.