Current Topics in Medicinal Chemistry - Volume 21, Issue 11, 2021

The COVID-19 pandemic turned the SARS-CoV-2 into the main target of scientific research all around the world. Many advances have already been made, but there is still a long way to go to solve the molecular mechanisms related to the process of the SARS-CoV-2 infection, as well as the particularities of the disease, its course and the complex host-pathogen relationships. However, a lot has been theorized and associated with COVID-19, like the worst prognosis of the disease among individuals with some comorbidities, like diabetes mellitus. In this perspective, diabetic patients are repeatedly associated with more severe cases of COVID-19 when compared to non-diabetic patients. Even though ACE2 (angiotensin-converting enzyme 2) was recognized as the host cell receptor for both binding and entering of SARS-CoV-2 particles, it was also pointed out that this enzyme plays an important protective role against pulmonary damage. Therefore, paradoxically as it may seem, the low baseline level of this receptor in diabetics is directly linked to a more expressive loss of ACE2 protective effect, which could be one of the possible factors for the worst prognosis of COVID-19. Still, COVID-19 may also have a diabetogenic effect. From this point of view, the main topics that will be highlighted are (i) the mechanism of the viral entry, with special attention to the cellular receptor (ACE2) and the viral binding protein (spike), (ii) the relationship among the renin-angiotensin system, the infection process and the patients' prognosis, (iii) the glucose control and the medicines used in this event, and (iv) a brief analysis on diabetes triggered by COVID-19.

Background: Schizophrenia is a complex disease with a putative genetic background. It was hypothesized that impaired mitochondrial function due to genetic alterations in mitochondrial DNA (mtDNA) could contribute to neurological conditions, including mental disorders. The aim of the study was to find out possible pathogenic mutations and/or variants in mtDNA potentially related to schizophrenia development. Objective: The study involved 37 patients with paranoid schizophrenia, whose mtDNA profiles were compared to those of 23 healthy controls. Methods: Patients and controls were assessed using PANSS (Positive and Negative Syndrome Scale) and General Health Questionnaire (GHQ), respectively. The entire mtDNA was sequenced by the NGS platform (MiSeq®, Illumina). Bioinformatics data were processed by mtDNA Variant Processor and Analyser (Illumina), mtDNA-Server, and SPSS-17. Results: A total of 480 mtDNA variants (single nucleotide replacements, point insertions, and deletions) were found. The polymorphic variant m.1811A>G (MT-RNR2) showed the highest frequency in schizophrenia (24.3%), as compared to the controls (4.3%) (p=0.07). Increased frequency was also found mainly in polymorphisms, belonging to complex 1 genes: MT-ND4 (11251G and 11467G), MT-ND3 (10398G), MT-ND1 (4216С), and MT-ND5 (12611G and 13708Ц#144;), some of which were associated with mitochondrial dysfunction. Two individual mutations were identified in the patients: a pathogenic one - m.11778 A>G (LHON) and a newly identified, potentially pathogenic - m.4115 Т>C (NADH dehydrogenase 1). Conclusion: Particular mtDNA variants predominantly in complex I, probably serve as a risk genetic background in schizophrenia. The presence of pathogenic mutations in patients with psychotic manifestations expands the clinical scope of mitochondrial diseases and deserves further investigation.

Major Depressive Disorder (MDD) and Bipolar Disorder (BD) have a high prevalence and detrimental socio-economic consequences for the patients and the community. Furthermore, the depressive symptomatology of both disorders is essentially identical, thus rendering the clinical differential diagnosis between the two significantly more difficult considering the concomitant lack of objective biomarkers. Mood disorders are multifactorial disorders the pathophysiology of which includes genetic, epigenetic, neurobiological, neuroimmunological, structural and functional brain alterations, etc. Aberrant genetic variants as well as changed differential expression of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have been implicated in the pathophysiology of MDD and BD. MiRNAs as well as lncRNAs have regulatory and modulating functions on protein-- coding gene expression thus influencing the remodeling of the architecture, neurotransmission, immunomodulation, etc. in the Central Nervous System (CNS) which are essential in the development of psychiatric disorders including MDD and BD. Moreover, both shared and distinct structural, connectivity, task-related and metabolic features have been observed via functional magnetic resonance imaging and magnetic resonance spectroscopy, suggesting the possibility of a dimensional continuum between the two disorders instead of a categorical differentiation. Aberrant connectivity within and between the Default Mode Network, the Salience Network, Executive Network, etc. as well as dysfunctional emotion, cognitive and executive processing have been associated with mood disorders. Therefore, the aim of this review is to explore a more multidimensional framework in the scientific research of mood disorders, including epigenetic and neuroimaging data in order to shape an outline for their translational capacity in clinical practice.

The peroxisome proliferator activated receptors (PPARs) are a superfamily of well-recognized ligand-binding nuclear receptors comprising three isoforms: PPARα, PPARγ, and PPARβ/δ. In response to endogenous lipid messengers, PPARs trigger the transcription of genes related to a wider spectrum of physiological phenomena, including fatty acid oxidation, inflammation, adipogenesis, among many others. Thus, the importance of PPARs as putative protective therapy in health issues has increased the interest of studying these nuclear receptors, including the management of neurodegenerative disorders, multiple sclerosis, and likely addiction. In recent years, several pieces of evidence from animal models have demonstrated the promising role of PPARs as a critical element for interventions in addictive behaviors by reducing the reinforcing properties of addictive substances such as alcohol. However, there is a lack of data in the scope and has so far been unexplored the function of PPARs in additional drugs such as cannabis, opioids, methamphetamine, or cocaine. A similar scenario has been found for the management of binge-type eating disorders. Thus, here we review recent advances in understanding the relevance of the PPAR controlling addiction.

Background: There is increasing evidence regarding the influence of the intestinal microbiota on the disease processes of various organs and systems. Dysbiosis, that is, alteration of the composition and function of the microbiota may constitute an important risk factor for the development of mental disorders, namely, schizophrenia. Objective: This works aims to review current evidence regarding the pathological mechanisms leading from dysbiosis to schizophrenia and in particular the deficit syndrome in schizophrenia. Methods: Scientific articles from PubMed, SCOPUS, EMBASE, and Web of Science Core Collection published between September 2017 and December 2020 were included in this review. Results: The commensal intestinal flora plays an important role in neurodevelopment. In the presence of dysbiosis, this maturation gets disturbed, resulting in the modification of brain structures and inflammatory responses at the intestinal, systemic, and Central Nervous System (CNS) levels. These disturbances may be linked to the development of symptoms of the disease. The microbiota exerts its influence on the CNS through several pathways, however, in this paper we focused on the membrane hypothesis and the inflammatory hypothesis. We explored the evidence concerning the use of probiotics, prebiotics, and fecal transplants. Conclusion: Although there is no consensus regarding the alterations that could constitute a risk factor for schizophrenia, some of the species appear to be more frequently altered, and their relationship with the host is dysregulated in patients at risk and with established schizophrenia, particularly in deficit schizophrenia.

Background: Although Autism Spectrum Disorder (ASD) is considered a heterogeneous neurological disease in childhood, a growing body of evidence associates it with mitochondrial dysfunction explaining the observed comorbidities. Introduction: The aim of this study is to identify variations in cellular bioenergetics and metabolism dependent on mitochondrial function in ASD patients and healthy controls using Peripheral Blood Mononuclear Cells (PBMCs). We hypothesized that PBMCs may reveal the cellular pathology and provide evidence of bioenergetic and metabolic changes accompanying the disease. Methods: PBMC from children with ASD and a control group of the same age and gender were isolated. All patients underwent an in-depth clinical evaluation. A well-characterized cohort of Bulgarian children is selected. Bioenergetic and metabolic studies of isolated PBMCs are performed with a Seahorse XFp analyzer. Results: Our data show that PBMCs from patients with ASD have increased respiratory reserve capacity (by 27.5%), increased maximal respiration (by 67%) and altered adaptive response to oxidative stress induced by DMNQ. In addition, we demonstrate а strong dependence on fatty acids and impaired ability to reprogram cell metabolism. The listed characteristics are not observed in the control group. These results can contribute to a better understanding of the underlying causes of ASD, which is crucial for selecting a successful treatment. Conclusion: The current study, for the first time, provides a functional analysis of cell bioenergetics and metabolic changes in a group of Bulgarian patients with ASD. It reveals physiological abnormalities that do not allow mitochondria to adapt and meet the increased energetic requirements of the cell. The link between mitochondria and ASD is not yet fully understood, but this may lead to the discovery of new approaches for nutrition and therapy.

Neurodegenerative diseases are complex disorders that cause neuron loss, brain aging and ultimately lead to death. These diseases are difficult to treat because of the complex nature of the nervous system, and the available medicines are unable to heal them effectively. This fact implies the need for novel therapeutics to be designed that are ready to stop or a minimum of retard the neurodegeneration process. These days, Computer-Assisted Drug Design (CADD) approaches are a passage to extend the drug development efficiency and to reduce time and cost because traditional drug discovery is both time-consuming as well as costly. Computational or in silico methods came up with powerful tools in drug design against neurodegenerative diseases. This review presents the approaches and theoretical basis of CADD. Also, the successful applications of various in silico studies, including homology modeling, molecular docking, Quantitative Structure-Activity Relationship (QSAR), Molecular Dynamic (MD), De novo drug design, Pharmacophore-based drug design, Virtual Screening (VS), LIGPLOT Analysis, In silico ADMET and drug safety prediction, for treating neurodegenerative diseases have also been included in this review. Major emphasis is given to Alzheimer’s disease and Parkinson’s disease because these two are the most familiar neurodegenerative diseases.