scholarly journals Natural Products That Target the Arginase in Leishmania Parasites Hold Therapeutic Promise

2021 ◽  
Vol 9 (2) ◽  
pp. 267
Author(s):  
Nicola S. Carter ◽  
Brendan D. Stamper ◽  
Fawzy Elbarbry ◽  
Vince Nguyen ◽  
Samuel Lopez ◽  
...  

Parasites of the genus Leishmania cause a variety of devastating and often fatal diseases in humans worldwide. Because a vaccine is not available and the currently small number of existing drugs are less than ideal due to lack of specificity and emerging drug resistance, the need for new therapeutic strategies is urgent. Natural products and their derivatives are being used and explored as therapeutics and interest in developing such products as antileishmanials is high. The enzyme arginase, the first enzyme of the polyamine biosynthetic pathway in Leishmania, has emerged as a potential therapeutic target. The flavonols quercetin and fisetin, green tea flavanols such as catechin (C), epicatechin (EC), epicatechin gallate (ECG), and epigallocatechin-3-gallate (EGCG), and cinnamic acid derivates such as caffeic acid inhibit the leishmanial enzyme and modulate the host’s immune response toward parasite defense while showing little toxicity to the host. Quercetin, EGCG, gallic acid, caffeic acid, and rosmarinic acid have proven to be effective against Leishmania in rodent infectivity studies. Here, we review research on these natural products with a focus on their promise for the development of treatment strategies as well as unique structural and pharmacokinetic/pharmacodynamic features of the most promising agents.

2020 ◽  
Vol 16 (1) ◽  
pp. 18-27
Author(s):  
Manzoor M. Khan

Interstitial lung disease, a term for a group of disorders, causes lung fibrosis, is mostly refractory to treatments and has a high death rate. After diagnosis the survival is up to 3 years but in some cases the patients live much longer. It involves a heterogenous group of lung diseases that exhibit progressive and irreversible destruction of the lung due to the formation of scars. This results in lung malfunction, disruption of gas exchange, and eventual death because of respiratory failure. The etiology of lung fibrosis is mostly unknown with a few exceptions. The major characteristics of the disease are comprised of injury of epithelial type II cells, increased apoptosis, chronic inflammation, monocytic and lymphocytic infiltration, accumulation of myofibroblasts, and inability to repair damaged tissue properly. These events result in abnormal collagen deposition and scarring. The inflammation process is mild, and the disease is primarily fibrotic driven. Immunosuppressants do not treat the disease but the evidence is evolving that both innate and acquired immune responses a well as the cytokines contribute to at least early progression of the disease. Furthermore, mediators of inflammation including cytokines are involved throughout the process of lung fibrosis. The diverse clinical outcome of the disease is due to different pattern of inflammatory markers. Nonetheless, the development of novel therapeutic strategies requires better understanding of the role of the immune response. This review highlights the role of the immune response in interstitial lung disease and considers the therapeutic strategies based on these observations. For this review several literature data sources were used to assess the role of the immune response in interstitial lung disease and to evaluate the possible therapeutic strategies for the disease.


2021 ◽  
Author(s):  
Jiawang Liu ◽  
Anan Liu ◽  
Youcai Hu

Cytochrome P450s, laccases, and intermolecular [4 + 2] cyclases, along with other enzymes were utilized to catalyze varied dimerization of matured natural products so as to create the structural diversity and complexity in microorganisms.


Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 265
Author(s):  
Maria-Luisa Pérez-Lozano ◽  
Annabelle Cesaro ◽  
Marija Mazor ◽  
Eric Esteve ◽  
Sabine Berteina-Raboin ◽  
...  

Osteoarthritis (OA) is a complex degenerative disease in which joint homeostasis is disrupted, leading to synovial inflammation, cartilage degradation, subchondral bone remodeling, and resulting in pain and joint disability. Yet, the development of new treatment strategies to restore the equilibrium of the osteoarthritic joint remains a challenge. Numerous studies have revealed that dietary components and/or natural products have anti-inflammatory, antioxidant, anti-bone-resorption, and anabolic potential and have received much attention toward the development of new therapeutic strategies for OA treatment. In the present review, we provide an overview of current and emerging natural-product-based research treatments for OA management by drawing attention to experimental, pre-clinical, and clinical models. Herein, we review current and emerging natural-product-based research treatments for OA management.


Author(s):  
Kristen Orumaa ◽  
Margaret R. Dunne

AbstractCOVID-19 is a respiratory disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It was first documented in late 2019, but within months, a worldwide pandemic was declared due to the easily transmissible nature of the virus. Research to date on the immune response to SARS-CoV-2 has focused largely on conventional B and T lymphocytes. This review examines the emerging role of unconventional T cell subsets, including γδ T cells, invariant natural killer T (iNKT) cells and mucosal associated invariant T (MAIT) cells in human SARS-CoV-2 infection.Some of these T cell subsets have been shown to play protective roles in anti-viral immunity by suppressing viral replication and opsonising virions of SARS-CoV. Here, we explore whether unconventional T cells play a protective role in SARS-CoV-2 infection as well. Unconventional T cells are already under investigation as cell-based immunotherapies for cancer. We discuss the potential use of these cells as therapeutic agents in the COVID-19 setting. Due to the rapidly evolving situation presented by COVID-19, there is an urgent need to understand the pathogenesis of this disease and the mechanisms underlying its immune response. Through this, we may be able to better help those with severe cases and lower the mortality rate by devising more effective vaccines and novel treatment strategies.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Woon Yong Jung ◽  
Kyueng-Whan Min ◽  
Young Ha Oh

AbstractThe histological classification of lung adenocarcinoma includes 5 types: lepidic, acinar, papillary, micropapillary and solid. The complex gene interactions and anticancer immune response of these types are not well known. The aim of this study was to reveal the survival rates, genetic alterations and immune activities of the five histological types and provide treatment strategies. This study reviewed the histological findings of 517 patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA) database and classified them into five types. We performed gene set enrichment analysis (GSEA) and survival analysis according to the different types. We found six oncogenic gene sets that were higher in lung adenocarcinoma than in normal tissues. In the survival analysis of each type, the acinar type had a favorable prognosis, and the solid subtype had an unfavorable prognosis; however, the survival differences between the other types were not significant. Our study focused on the solid type, which had the poorest prognosis. The solid type was related to adaptive immune resistance associated with elevated CD8 T cells and high CD274 (encoding PD-L1) expression. In the pathway analyses, the solid type was significantly related to high vascular endothelial growth factor (VEGF)-A expression, reflecting tumor angiogenesis. Non-necrosis/low immune response affected by high VEGF-A was associated with worse prognosis. The solid type associated with high VEGF-A expression may contribute to the development of therapeutic strategies for lung adenocarcinoma.


Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 993
Author(s):  
Renuka Raman ◽  
Krishna J. Patel ◽  
Kishu Ranjan

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of the coronavirus disease 2019 (COVID-19) pandemic, which has been a topic of major concern for global human health. The challenge to restrain the COVID-19 pandemic is further compounded by the emergence of several SARS-CoV-2 variants viz. B.1.1.7 (Alpha), B.1.351 (Beta), P1 (Gamma) and B.1.617.2 (Delta), which show increased transmissibility and resistance towards vaccines and therapies. Importantly, there is convincing evidence of increased susceptibility to SARS-CoV-2 infection among individuals with dysregulated immune response and comorbidities. Herein, we provide a comprehensive perspective regarding vulnerability of SARS-CoV-2 infection in patients with underlying medical comorbidities. We discuss ongoing vaccine (mRNA, protein-based, viral vector-based, etc.) and therapeutic (monoclonal antibodies, small molecules, plasma therapy, etc.) modalities designed to curb the COVID-19 pandemic. We also discuss in detail, the challenges posed by different SARS-CoV-2 variants of concern (VOC) identified across the globe and their effects on therapeutic and prophylactic interventions.


2021 ◽  
Vol 85 (1) ◽  
pp. 42-52
Author(s):  
Taro Shiraishi ◽  
Tomohisa Kuzuyama

Abstract Phosphonates are organophosphorus compounds possessing a characteristic C−P bond in which phosphorus is directly bonded to carbon. As phosphonates mimic the phosphates and carboxylates of biological molecules to potentially inhibit metabolic enzymes, they could be lead compounds for the development of a variety of drugs. Fosfomycin (FM) is a representative phosphonate natural product that is widely used as an antibacterial drug. Here, we review the biosynthesis of FM, which includes a recent breakthrough to find a missing link in the biosynthetic pathway that had been a mystery for a quarter-century. In addition, we describe the genome mining of phosphonate natural products using the biosynthetic gene encoding an enzyme that catalyzes C–P bond formation. We also introduce the chemoenzymatic synthesis of phosphonate derivatives. These studies expand the repertoires of phosphonates and the related biosynthetic machinery. This review mainly covers the years 2012-2020.


mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Daniela B. B. Trivella ◽  
Rafael de Felicio

ABSTRACT Natural products are the richest source of chemical compounds for drug discovery. Particularly, bacterial secondary metabolites are in the spotlight due to advances in genome sequencing and mining, as well as for the potential of biosynthetic pathway manipulation to awake silent (cryptic) gene clusters under laboratory cultivation. Further progress in compound detection, such as the development of the tandem mass spectrometry (MS/MS) molecular networking approach, has contributed to the discovery of novel bacterial natural products. The latter can be applied directly to bacterial crude extracts for identifying and dereplicating known compounds, therefore assisting the prioritization of extracts containing novel natural products, for example. In our opinion, these three approaches—genome mining, silent pathway induction, and MS-based molecular networking—compose the tripod for modern bacterial natural product discovery and will be discussed in this perspective.


2020 ◽  
Author(s):  
Ravi Philip Rajkumar

AbstractBackgroundThe COVID-19 pandemic has affected the entire world, but there are wide variations in prevalence and mortality across nations. Genetic variants which influence behavioural or immune responses to pathogens, selected for by pathogen pressure, may influence this variability. Two relevant polymorphisms in this context are the s allele of the serotonin transporter promoter (5-HTTLPR) and the G allele of the interleukin-6 gene (IL-6 rs1800795).MethodsThe frequencies of the 5-HTTLPR s allele and IL-6 rs1800795 G allele were obtained from published data. The correlations between these allele frequencies and the prevalence and mortality rates of COVID-19 were examined across 44 nations.ResultsThe IL-6 rs1800795 G allele was negatively correlated with COVID-19 prevalence (ρ = −0.466, p < 0.01) and mortality (ρ = −0.591, p<0.001) across nations. The 5-HTTLPR s allele was negatively correlated with COVID-19 mortality rates (ρ = −0.437, p = 0.023).ConclusionsThese results suggest that a significant relationship exists between genetic variants that influence behavioural and immune responses to pathogens and indices of the impact of COVID-19 across nations. Further investigation of these variants and their correlates may permit the development of better preventive or therapeutic strategies in the management of the COVID-19 pandemic.


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