Current Medicinal Chemistry - Volume 29, Issue 24, 2022

Background: Alzheimer’s disease (AD) is the most common form of dementia worldwide, with approximately 6 million cases reported in America in 2020. The clinical signs of AD include cognitive dysfunction, apathy, anxiety and neuropsychiatric signs, and pathogenetic mechanisms that involve amyloid peptide-β extracellular accumulation and tau hyperphosphorylation. Unfortunately, current drugs to treat AD can provide only symptomatic relief but are not disease-modifying molecules able to revert AD progression. The endogenous modulator adenosine, through A2A receptor activation, plays a role in synaptic loss and neuroinflammation, which are crucial for cognitive impairment and memory damage. Objective: In this review, recent advances covering A2A adenosine receptor antagonists will be extensively reviewed, providing a basis for the rational design of future A2A inhibitors. Methods: Herein, the literature on A2A adenosine receptors and their role in synaptic plasticity and neuroinflammation, as well as the effects of A2A antagonism in animal models of AD and in humans, are reviewed. Furthermore, current chemical and structure-based strategies are presented. Results: Caffeine, the most widely consumed natural product stimulant and an A2A antagonist, improves human memory. Similarly, synthetic A2A receptor antagonists, as described in this review, may provide a means to fight AD. Conclusion: This review highlights the clinical potential of A2A adenosine receptor antagonists as a novel approach to treat patients with AD.

This review describes the use of lipid-based nanocarriers (LNCs) for the parenteral delivery of pharmaceutical actives. Firstly, the two generations of LNCs, namely solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), are explained in terms of preparation, characterization and stability. Although the use of LNCs through parenteral administration has shown many benefits, their use is limited by opsonization, an immune process that causes their short half-life (3-5 min). Therefore, many strategies are discussed to realize “stealth” systems suitable for parenteral administration. The requirements and applications of parenteral lipid nanoparticles are reviewed for the delivery of natural compounds, synthetic drugs and genetic materials. Recently, the latter application has been of remarkable interest due to the numerous benefits of mRNA vaccines to fight the Covid-19 pandemic.

Nanotechnology has been extensively exploited for its enormous therapeutic and diagnostic potential in the management of multiple disorders. It employs nanomaterials as drug carriers with enhanced efficacy and limited side effects on normal tissues. A lot of nanomaterials have been studied and produced, imminently reforming the treatment and diagnostics of numerous malignancies, including cancer. The purpose of the present study is to explore the role of nanotechnology-based devices/therapies that have a vital function in the therapeutics and diagnostics of cancer with potential impact at three levels: early detection, tumor imaging, and drug delivery methods. Concentrating on cancer, promising nanotechnology-based approaches have been planned to satisfy the need for targeted specificity of traditional agents of chemotherapeutics, in addition to early recognition of malignant and precancerous lesions. Prostate cancer is the fifth most wellknown cancer worldwide and the second most usually detected cancer in men. Therefore, there is a crucial need to improve therapeutic prospects for the diagnosis and treatment of prostate cancer via the exploitation of the potential of nanomaterials for cell-targeted specificity and improved primary diagnosis of precancerous tumors. The present review, therefore, focuses on summarizing all prospective applications of nanotechnology in the prognosis and diagnosis of prostate cancer, which would further help researchers to elucidate a more potent therapeutic approach for the better management of prostate cancer in the days ahead.

Lipid peroxidation-driven iron-dependent ferroptosis is a regulated cell death mechanism implicated in numerous diseases, such as neurological diseases, kidney injury, ischemia, and tumors, including prostate cancer. The cellular mechanisms of ferroptosis are strongly associated with iron, reactive oxygen species and amino acid metabolic pathways. Several compounds, namely ferroptosis inducers, impact these pathways and trigger ferroptosis by i) inhibiting Xc - transporter system, ii) impairing GPX4 functions and iii) oxidizing iron and polyunsaturated phospholipids. Preclinical studies show that in combination with conventional anticancer drugs, ferroptosis inducers are effective in prostate cancer and in combating the progression towards the castration-resistant disease. This review overviews the mechanisms implicated in ferroptosis and discusses the findings achieved in prostate cancer.

Background: D-amino acids are present in the human body originating from diet, bacterial flora, and endogenous synthesis (at least for D-serine and, probably, D-aspartate). D-amino acids are involved in important physiological processes (e.g., D-serine and D-aspartate act on the N-methyl-D-aspartate receptor as co-agonist and agonist, respectively) and increasing evidence links D-amino acids to different pathological states. Methods: Determination of D-amino acids levels in blood is mainly based on enantiomeric separations by high performance liquid chromatography. Because of the low amount of D-enantiomers compared to the corresponding L-amino acids and the high background noise associated with biological matrices, positive and negative controls are absolutely required to obtain reliable values. Results: Altered levels of D-serine in blood have been reported in several neurological and psychiatric disorders: it has been proposed as promising biomarker in schizophrenia, Alzheimer’s disease, and amyotrophic lateral sclerosis. Indeed, D-serine levels seem an appropriate predictor of anti-depressant response in major depressive disorder and posttraumatic stress disorder, as well as a prognostic biomarker of early cognitive decline, especially when considering D-serine and D-proline levels simultaneously. Furthermore, D-amino acids seem useful biomarkers for pathologies not related to the central nervous system, such as pancreatic cancer and chronic kidney diseases. Conclusion: This is the first review focusing on the determination of blood levels of Damino acids as diagnostic and prognostic biomarkers. The experimental evidence of involvement of D-amino acids in various physiological pathways suggest investigating their levels in additional pathologies too, such as diabetes mellitus. In conclusion, the levels of D-amino acids in blood may represent novel diagnostic peripheral biomarkers for various disorders. Further studies are required to standardize/automatize the determinations and for confirming their clinical effectiveness.

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) mainly affecting the colon and the rectum. Its main characteristics include relapsing and remitting mucosal inflammation, starting in the rectum and typically extending continuously proximally through part of or the entire colon. UC pathogenesis depends on multiple factors, such as genetic predisposition, defects in the epithelial barrier, dysregulated immune responses, and environmental causes. The most frequent symptoms are abdominal pain, weight loss, mucus discharge, bloody diarrhoea, incontinence, nocturnal defecations, fever, and anemia. Existing therapies for UC include 5-aminosalicylic acid (5-ASA) and its derivatives, steroids, immunosuppressants, and biological drugs. However, limited efficacy and unwanted adverse effects hardly limit these strategies of treatment. In the last decades, research studies have been driven towards complementary and alternative medicines for the treatment of UC. Various nutraceuticals have exhibited promising results in modulating intestinal inflammation while improving symptoms. These compounds possess a wide spectrum of positive health effects evidenced by in vitro studies, characterized by their involvement in antioxidant defenses, cell proliferation, and gene expression. The present review analyzes the available data about the different types of nutraceuticals and their potential effectiveness as adjuvant therapy of IBD, with particular emphasis to UC.

Bisphenol A (BPA) is an industrial ubiquitous compound, frequently used to produce synthetic polymers and epoxy resins. BPA is a well-recognized endocrine disruptor and xenoestrogen compound. Evidence from epidemiological and experimental studies suggests that perinatal BPA exposure (gestation and/or lactation) increases the risk of developing various diseases, including the cardiovascular system. Developmental programming refers to environmental insults during the critical window of development that affect the structure and physiology of body systems, causing permanent changes in later stages. BPA influences the developmental programming of non-communicable diseases in the offspring. In the present review, we discuss the developmental programming of cardiovascular diseases related to perinatal exposure to BPA, supported by epidemiological and experimental evidence from published literature. The majority of the reported studies found a positive association between perinatal BPA exposure and adverse cardiovascular repercussions in the fetal, neonatal, and adulthood stages. The possible underlying mechanisms include epigenetic modifications of genes involved in cardiac muscle development, autonomic tone, collagenous and non-collagenous extracellular matrix, cardiac remodeling and calcium homeostasis, and mitochondrial energy metabolism. Epigenetics can modify the outcome of any disease. Hence, in the present review, we also discuss the role of epigenetics in preventing cardiovascular diseases following perinatal exposure to BPA. We also highlight how future treatment and drug delivery related to cardiovascular involvement could be based on epigenetic markers.

Multidrug resistance (MDR) in the opportunistic pathogen Candida albicans is defined as non-susceptibility to at least one agent in two or more drug classes. This phenomenon has been increasingly reported since the rise in the incidence of fungal infections in immunocompromised patients at the end of the last century. After the discovery of efflux pump overexpression as a principal mechanism causing MDR in Candida strains, drug discovery targeting fungal efflux transporters has had a growing impact. Chemosensitization aims to enhance azole intracellular concentrations through combination therapy with transporter inhibitors. Consequently, the use of drug efflux inhibitors combined with the antifungal agent will sensitize the pathogen. As a result, the use of lower drug concentrations will reduce possible adverse effects on the host. Through an extensive revision of the literature, this review aims to provide an exhaustive and critical analysis of the studies carried out in the past two decades regarding the chemosensitization strategy to cope with multidrug resistance in C. albicans. This work provides a deep analysis of the research on the inhibition of drug-efflux membrane transporters by prenylated flavonoids and the interactions of these phytocompounds with azole antifungals as an approach to chemosensitize multidrug-resistant C. albicans strains. We highlight the importance of prenylflavonoids and their particular chemical and pharmacological characteristics that make them excellent candidates with therapeutic potential as chemosensitizers. Finally, we propose the need for further research on prenyl flavonoids as inhibitors of drug-efflux mediated fungal resistance.

Background: Peptidoglycan is an essential component of the cell wall in all bacteria. In particular, the cell walls of Gram-positive bacteria are composed mostly of a thick layer of peptidoglycan. Its accessibility has important implications for their sensing in whole bacterial detection methodologies. Indeed, there is an urgent demand for rapid tests which can identify whole bacteria, e.g., directly at the point of care. Objective: The aim of this work is to explore the suitability of RipA, a key cell division protein of M. tuberculosis, for whole cell biosensing of Gram-positive bacteria. Methods: We here conducted Molecular Dynamics (MD) studies aimed at the understanding of the structural and dynamic features of active RipA and at the design of a suitable bioreceptor. Based on these studies, we engineered a RipA variant for covalent oriented immobilisation on golden surfaces and are able to bind peptidoglycan, albeit without degrading it. Surface Plasmon Resonance (SPR) was employed to check the ability of functionalized golden chips to recognize whole bacteria. Results: MD analyses elucidated the structural details of the active form of RipA and suggested that this enzyme, once inactivated, presents a rigid and well-exposed peptidoglycan recognition cleft. We engineered RipA for proper oriented immobilisation on golden chips for SPR studies. Results show that once chemically coupled to a golden chip, the developed RipA-based bioreceptor is able to detect B. subtilis, used as a model in a concentration-dependent mode. Conclusion: Results highlight the potential of the engineered molecule to be integrated in the development of early warning biosensors for Gram-positive contamination in clinical diagnosis or food-borne infections.

Background: Ovarian cancer is one of the most aggressive types of gynecologic cancers. Many patients have a relapse within two years after diagnosis and subsequent therapy. Among different genetic changes generally believed to be important for the development of cancer, TP53 is the most common mutation in the case of ovarian tumors. Objective: Our work aims to analyze the outcomes of different comparisons based on the overall survival of ovarian cancer patients, the determination of TP53 status and the amount of p53 protein in tumor tissues. Methods: We analyzed and compared a collective of 436 ovarian patients’ data. The extracted data include TP53 mutation status, p53 protein level and information on the overall survival. Values for p53 protein level in dependence of the TP53 mutation status were compared using the Independent Samples t-Test. Survival analyses were displayed by Kaplan- Meier plots, using the log-rank test to check for statistical significance. Results: We have not found any statistically significant correlations between the determination of TP53 status or the amount of p53 protein in tumor tissues and the overall survival of ovarian cancer patients. Conclusion: In ovarian tumors the determination of both the TP53 status as well as the p53 protein amount has only limited diagnostic importance.