Targeting complement cascade: an alternative strategy for COVID-19

The complement system is a stakeholder of the innate and adaptive immune system and has evolved as a crucial player of defense with multifaceted biological effects. Activation of three complement pathways leads to consecutive enzyme reactions resulting in complement components (C3 and C5), activation of mast cells and neutrophils by anaphylatoxins (C3a and C5a), the formation of membrane attack complex (MAC) and end up with opsonization. However, the dysregulation of complement cascade leads to unsolicited cytokine storm, inflammation, deterioration of alveolar lining cells, culminating in acquired respiratory destructive syndrome (ARDS). Similar pathogenesis is observed with the middle east respiratory syndrome (MERS), severe acquired respiratory syndrome (SARS), and SARS-CoV-2. Activation of the lectin pathway via mannose-binding lectin associated serine protease 2 (MASP2) is witnessed under discrete viral infections including COVID-19. Consequently, the spontaneous activation and deposits of complement components were traced in animal models and autopsy of COVID-19 patients. Pre-clinical and clinical studies evidence that the inhibition of complement components results in reduced complement deposits on target and non-target tissues, and aid in recovery from the pathological conditions of ARDS. Complement inhibitors (monoclonal antibody, protein, peptide, small molecules, etc.) exhibit great promise in blocking the activity of complement components and its downstream effects under various pathological conditions including SARS-CoV. Therefore, we hypothesize that targeting the potential complement inhibitors and complement cascade to counteract lung inflammation would be a better strategy to treat COVID-19.N/

Adriamycin-induced cardiomyopathy can serve as a model for diabetic cardiomyopathy – a hypothesis

Diabetic cardiomyopathy is one of the life threatening complications of diabetes. A number of animal models are being used for studying diabetic cardiomyopathy. In laboratory animal models, induction of cardiomyopathy happens in two stages: first being the induction of diabetic condition and the second being the induction of cardiomyopathy by prolonging diabetic condition. It takes a longer time to develop diabetes with the limited success rate for development of cardiomyopathy. Adriamycin is an effective anti-cancer drug limited by its major side-effect cardiomyopathy. A number of features of Adriamycin treatment mimics diabetes. We postulate that Adriamycin-induced cardiomyopathy might be used as a model system to study diabetic cardiomyopathy in rodents since a number of features of both the cardiomyopathies overlap. Left ventricular hypertrophy, systolic and diastolic dysfunction, myofibrillar loss, and fibrosis are hallmarks of both of the cardiomyopathies. At the molecular level, calcium signaling, endoplasmic reticulum stress, advance glycation endproduct activation, mitochondrial dysfunction, inflammation, lipotoxicity and oxidative stress are similar in both the cardiomyopathies. The signature profile of both the cardiomyopathies shares commonalities. In conclusion, we suggest that Adriamycin induced cardiomyopathic animal model can be used for studying diabetic cardiomyopathy and would save time for researchers working on cardiomyopathy developed in rodent using the traditional method

Aphrodisiac Performance of Bioactive Compounds from Mimosa pudica Linn.: In Silico Molecular Docking and Dynamics Simulation Approach

Plants and their derived molecules have been traditionally used to manage numerous pathological complications, including male erectile dysfunction (ED). Mimosa pudica Linn. commonly referred to as the touch-me-not plant, and its extract are important sources of new lead molecules in drug discovery research. The main goal of this study was to predict highly effective molecules from M. pudica Linn. for reaching and maintaining penile erection before and during sexual intercourse through in silico molecular docking and dynamics simulation tools. A total of 28 bioactive molecules were identified from this target plant through public repositories, and their chemical structures were drawn using Chemsketch software. Graph theoretical network principles were applied to identify the ideal target (phosphodiesterase type 5) and rebuild the network to visualize the responsible signaling genes, proteins, and enzymes. The 28 identified bioactive molecules were docked against the phosphodiesterase type 5 (PDE5) enzyme and compared with the standard PDE5 inhibitor (sildenafil). Pharmacokinetics (ADME), toxicity, and several physicochemical properties of bioactive molecules were assessed to confirm their drug-likeness property. Molecular dynamics (MD) simulation modeling was performed to investigate the stability of PDE5–ligand complexes. Four bioactive molecules (Bufadienolide (−12.30 kcal mol−1), Stigmasterol (−11.40 kcal mol−1), Isovitexin (−11.20 kcal mol−1), and Apigetrin (−11.20 kcal mol−1)) showed the top binding affinities with the PDE5 enzyme, much more powerful than the standard PDE5 inhibitor (−9.80 kcal mol−1). The four top binding bioactive molecules were further validated for a stable binding affinity with the PDE5 enzyme and conformation during the MD simulation period as compared to the apoprotein and standard PDE5 inhibitor complexes. Further, the four top binding bioactive molecules demonstrated significant drug-likeness characteristics with lower toxicity profiles. According to the findings, the four top binding molecules may be used as potent and safe PDE5 inhibitors and could potentially be used in the treatment of ED