Current Drug Targets - Volume 22, Issue 17, 2021

Lysyl oxidases (LOXs) are amino oxidase enzymes that catalyze the oxidative deamination of lysine and hydroxylysine residues to form allysine, the first step towards the development of the final cross-linking reaction in collagens, a crucial macromolecule that reinforces extracellular matrices. Basement membranes are specialized extracellular matrices that are essential components of the glomerular filtration barrier, which also support tubular epithelial cells. Lysyl oxidases are post-translational enzymes indispensable for tissue architecture, participating actively in the development and function of kidneys. The differential expression and dysregulation of these enzymes promote diabetic nephropathy, one of the major complications observed in end-stage renal diseases. In addition, these enzymes act as transcription factors that trigger the epithelial-mesenchymal transition responsible for the generation of different cancers. In the kidney, the expression studies in physiological conditions identified LOXL1 and LOXL2 as constituent proteins of glomerular basement membranes. Besides, LOX and LOXL2 are upregulated in fibrosis and renal cell carcinoma. The current review summarizes the physiological expression of LOXs enzymes in the nephrons, including glomerulus and tubules. Their roles in renal diseases are particularly highlighted in diabetic nephropathy and renal cell carcinoma, two pathophysiological conditions where these enzymes have been demonstrated to participate. The focus of the present study is to describe and discuss the current understanding in this field. The current potential of LOXs enzymes as a biomarker and pharmacological target to kidney diseases that involves extracellular matrix cross-linking enzymes is also discussed. LOXs isoforms and their capacity as therapeutic targets could be used for diagnostic and prognostic purposes and in treating these renal complications.

Coumarins, a heterocyclic benzo-α-pyrones and naturally occurring ring structure that possess significant pharmacological properties, have attracted the attention of researchers and medicinal chemists to reveal the suitability of both natural and synthetic coumarins as drugs. Many compounds have been synthesized utilizing the basic coumarin structure. The diverse synthetic methods resulted in the synthesis of important coumarin derivatives that offer a wide range of biological properties as antimicrobial, anticancer, anti-inflammatory, antioxidant, antidiabetic and antidepressant that make them potential drug candidates. With a particular interest in ulcers, coumarins have shown potential inhibition against urease enzyme. In recent years, scientists have emphasized the anti-urease activity of coumarins due to their low toxicity. The aim of this review is to compile data from recent research about anti-urease activities of coumarins and structure-activity relationship studies of the coumarin ring structure. Investigation of different structural substitutions in coumarin rings may help researchers to design new compounds with strong and effective anti- urease abilities.

Thieno[3,2-d]pyrimidine ring framework comprises a significant class of heterocyclics that serve as a promising platform showing different pharmacological activities. The interest in thieno[3,2-d]pyrimidine cores for pharmaceutical products makes this scaffold an exceptionally helpful building block for organic chemistry. This review presents current research on thieno[3,2- d]pyrimidines and elucidates their biological importance in anti-cancer, anti-infectious, anticonvulsant, anti-diabetic, CNS, and osteoporosis drug discoveries. Patents on the thieno[3,2- d]pyrimidines are also elaborated as a piece of useful information. Here, we additionally focus on the synthesis of this vital ring and the discovery of new thieno[3,2-d]pyrimidines.

Bacterial resistance has become a major global concern, affecting about 500, 000 individuals in 22 countries. Thus, it is clear that Gram-negative bacteria have been receiving more attention in this scenario. These bacteria perform several resistance mechanisms, such as modifying lipid A from lipopolysaccharides as a product of the mcr-1 gene expression. This gene was initially identified in animals; however, it quickly spread to humans, spreading to 70 countries. Mcr-1 gene attributes resistance to polymyxin B and colistin, which are drugs established as the last alternative to combat Enterobacteriaceae bacteria. Notwithstanding the prevalence and lack of antibiotic therapies for such bacteria, this article aimed to compile information about natural compounds against the resistance attributed by this gene, including the activity of isolated colistin or its associations with other antibiotics. Among the studies that evaluated colistin's synergistic action with other compounds, azidothymidine and isoalantholactone stood out. On the other hand, the paenipeptin 1 analog showed satisfactory activities when associated with other antibiotics. Besides, it is worth mentioning that molecular docking results between ostole and eugenol toward phosphoethanolamine transferase MCR-1 revealed that these compounds could interact with critical amino acid residues for the catalytic action of this enzyme. Based on this, natural agents' role is evident against infections caused by mcr-1-positive bacteria, directly contributing to the development of new effective pharmacotherapies.

The coronavirus disease 2019 (COVID-19) pandemic, due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in December 2019 and has rapidly spread globally. As the confirmed number of cases has reached 83 million worldwide, the potential severity and the deadly complications of the disease requires urgent development of effective drugs for prevention and treatment. No proven effective treatment for this virus currently exists. Most of the antiviral discovery efforts are focused on the repurposing of approved or clinical stage drugs. This review highlights the small-molecule repurposed antiviral agents that are currently under investigation in clinical trials for COVID-19. These include viral polymerase and protease inhibitors remdesivir, galidesivir, favipiravir, ribavirin, sofosbuvir, tenofovir/emtricitabine, baloxavir marboxil, EIDD-2801, lopinavir/ritonavir; virus-/host-directed viral entry and fusion inhibitors arbidol chloroquine/hydroxychloroquine, chlorpromazine, camostat mesylate, nafamostat mesylate, bromhexine and agents with diverse/unclear mechanism of actions as oseltamivir, triazavirin, ivermectin, nitazoxanide, niclosamide and BLD-2660. The published preclinical and clinical data to date on these drugs as well as the mechanisms of action are reviewed.

Background: By the end of 2019, the sudden outbreak of the novel coronavirus disease (COVID-19) has become a global threat. It is called COVID-19 because it was caused by the novel coronavirus (SARS-COV-2) in 2019. A total of 1.9 M deaths and 87.9 M cases have been reported all over the world, where 49M cases have recovered so far. Scientists are working hard to find chemotherapeutics and vaccines for COVID-19. Mutations in SARS-CoV-2 have been observed in a combination of several hazardous stresses, making them more resistant and beneficial. So to break down the viral system, the disease targets are examined. Objective: In today's review, a comprehensive study of spike protein explains the main purpose of the novel coronavirus and how to prevent the spread of the disease virus cross-transmission from infected to a healthy person. Methods: Covid-19 has already been declared a pandemic by the World Health Organization (WHO) due to its result in causing death and severe illness globally. SARS-CoV-2 is highly contagious; however, the intermediate host of the novel coronavirus is not clear. To explore the mechanisms of disease, one of the viral targets, such as the spike protein that binds to human cells and causes the disease by altering its genetic structure which is considered along with potential inhibitors. Results: It has been shown that the interaction of receptor-binding domain (RBD) protein of SARS- CoV-2 spike and the angiotensin-converting enzyme 2 (ACE2) host receptor and further replication of coronavirus spike protein causes its invasion in the host cell. The human Lymphocyte antigen 6 complex, Locus E (LY6E), inhibits the entry of CoV into host cells by interfering with the human gene, inducing spike protein-mediated membrane fusion. Some natural formulations have also been shown to prevent spike protein from binding to the host cell. Conclusion: With the development of the LY6E gene activator that can inhibit spike protein- ACE2-mediated membrane fusion, new opportunities for SARS-CoV-2 treatment may emerge. Existing antiviral fusion inhibitors and natural compounds targeting spike resistance can serve as a template for further SARS-CoV-2 drug formulation.