scholarly journals Investigating Structural Property Relationships to Enable Repurposing of Pharmaceuticals as Zinc Ionophores

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2032
Author(s):  
Oisín Kavanagh ◽  
Robert Elmes ◽  
Finbarr O’Sullivan ◽  
John Farragher ◽  
Shane Robinson ◽  
...  
Keyword(s):  
Cellular Systems ◽  
Zinc Homeostasis ◽  
In Vitro Assays ◽  
Growth Of Knowledge ◽  
Structural Database ◽  
Key Functional Groups ◽  
And Function ◽  
Ionophoric Activity ◽  
Endogenous Enzymes

The importance of zinc in biology has gained greater recognition in recent years due to its essential contributions to the function of many endogenous enzymes. Disruption of zinc homeostasis may be useful in treating pathological conditions, such as Alzheimer’s, and for antiviral purposes. Despite the growth of knowledge and increased interest in zinc, little is known about the structure and function of zinc ionophores. In this study we analyse the Cambridge Structural Database and solution complexation studies found in the literature to identify key functional groups which may confer zinc ionophorism. Pharmaceuticals, nutraceuticals and amino acids with these functionalities were selected to enable us to explore the translatability of ionophoric activity from in vitro assays to cellular systems. We find that although certain species may complex to zinc in the solid and solution states, and may carry ions across simple membrane systems, this does not necessarily translate into ionophoric activity. We propose that the CSD can help refine key functionalities but that ionophoric activity must be confirmed in cellular systems.

scholarly journals Metabolic endotoxemia promotes adipose dysfunction and inflammation in human obesity

2019 ◽  
Vol 316 (2) ◽  
pp. E319-E332 ◽  
Author(s):  
Mercedes Clemente-Postigo ◽  
Wilfredo Oliva-Olivera ◽  
Leticia Coin-Aragüez ◽  
Bruno Ramos-Molina ◽  
Rosa María Giraldez-Perez ◽  
...  
Keyword(s):  
Metabolic Diseases ◽  
In Vitro Assays ◽  
Low Grade ◽  
Human Obesity ◽  
Gene And Protein Expression ◽  
And Function ◽  
Adipose Dysfunction ◽  
High Degree ◽  
Metabolic Endotoxemia

Impaired adipose tissue (AT) lipid handling and inflammation is associated with obesity-related metabolic diseases. Circulating lipopolysaccharides (LPSs) from gut microbiota (metabolic endotoxemia), proposed as a triggering factor for the low-grade inflammation in obesity, might also be responsible for AT dysfunction. Nevertheless, this hypothesis has not been explored in human obesity. To analyze the relationship between metabolic endotoxemia and AT markers for lipogenesis, lipid handling, and inflammation in human obesity, 33 patients with obesity scheduled for surgery were recruited and classified according to their LPS levels. Visceral and subcutaneous AT gene and protein expression were analyzed and adipocyte and AT in vitro assays performed. Subjects with obesity with a high degree of metabolic endotoxemia had lower expression of key genes for AT function and lipogenesis ( SREBP1, FABP4, FASN, and LEP) but higher expression of inflammatory genes in visceral and subcutaneous AT than subjects with low LPS levels. In vitro experiments corroborated that LPS are responsible for adipocyte and AT inflammation and downregulation of PPARG, SCD, FABP4, and LEP expression and LEP secretion. Thus, metabolic endotoxemia influences AT physiology in human obesity by decreasing the expression of factors involved in AT lipid handling and function as well as by increasing inflammation.

scholarly journals The Structure and Function of Alkamides in Mammalian Systems

2021 ◽  
Author(s):  
Stephanie E. Johnstone ◽  
Scott M. Laster
Keyword(s):  
Fatty Acid ◽  
Intracellular Signaling ◽  
Viral Infections ◽  
Cellular Systems ◽  
Surface Receptors ◽  
Head Groups ◽  
Liver And Kidney ◽  
And Function

Alkamides, or alkylamides, are fatty acid amides produced by plants from the genera Echinacea, Acmella, Spilanthes, and Heliopsis among others. Alkamides contain varying head groups, an amide moiety, and a fatty acid tail with varying numbers of carbons and double and triple bonds. Extracts from these plants have been used worldwide by native peoples for the treatment of numerous medical disorders, including bacterial and viral infections, inflammation, liver and kidney disorders, and pain. In vitro, these molecules display a variety of different activities depending on the cell type tested. Studies with neurons, macrophages and mast cells have revealed interactions between alkamides and a number of different cells surface receptors and intracellular signaling molecules. Generally, the alkamides have been found to exert suppressive effects, inhibiting cellular activation. In this report we introduce the structure of alkamides and review their effects in a number of different cellular systems. We also describe structure:function studies that have been performed with alkamides. While these studies have not as yet revealed general rules for alkamide activity, interesting insights have been revealed. The stage is set for the development of synthetic, designer alkamides with targeted in vivo activities.

scholarly journals Histamine H2 receptor radioligands: triumphs and challenges

2021 ◽  
Author(s):  
Steffen Pockes ◽  
Katharina Tropmann
Keyword(s):  
Receptor Expression ◽  
In Vitro Assays ◽  
Histamine H2 Receptor ◽  
Drug Candidates ◽  
Carbon 14 ◽  
The Central Nervous System ◽  
And Function ◽  
Role And Function

Since the discovery of the histamine H2 receptor (H2R), radioligands were among the most powerful tools to investigate its role and function. Initially, radiolabeling was used to investigate human and rodent tissues regarding their receptor expression. Later, radioligands gained increasing significance as pharmacological tools in in vitro assays. Although tritium-labeling was mainly used for this purpose, labeling with carbon-14 is preferred for metabolic studies of drug candidates. After the more-or-less successful application of numerous labeled H2R antagonists, the recent development of the G protein-biased radioligand [3H]UR-KAT479 represents another step forward to elucidate the widely unknown role of the H2R in the central nervous system through future studies.

scholarly journals FOXL2 is a Progesterone Target Gene in the Endometrium of Ruminants

2020 ◽  
Vol 21 (4) ◽  
pp. 1478 ◽  
Author(s):  
Caroline Eozenou ◽  
Audrey Lesage-Padilla ◽  
Vincent Mauffré ◽  
Gareth D. Healey ◽  
Sylvaine Camous ◽  
...  
Keyword(s):  
Oestrous Cycle ◽  
In Vitro Assays ◽  
Control Group ◽  
Interferon Tau ◽  
Forkhead Box ◽  
Mrna And Protein Expression ◽  
Exogenous Progesterone ◽  
And Function ◽  
Foxl2 Gene

Forkhead Box L2 (FOXL2) is a member of the FOXL class of transcription factors, which are essential for ovarian differentiation and function. In the endometrium, FOXL2 is also thought to be important in cattle; however, it is not clear how its expression is regulated. The maternal recognition of pregnancy signal in cattle, interferon-Tau, does not regulate FOXL2 expression. Therefore, in the present study, we examined whether the ovarian steroid hormones that orchestrate implantation regulate FOXL2 gene expression in ruminants. In sheep, we confirmed that FOXL2 mRNA and protein was expressed in the endometrium across the oestrous cycle (day 4 to day 15 post-oestrus). Similar to the bovine endometrium, ovine FOXL2 endometrial expression was low during the luteal phase of the oestrous cycle (4 to 12 days post-oestrus) and at implantation (15 days post-oestrus) while mRNA and protein expression significantly increased during the luteolytic phase (day 15 post-oestrus in cycle). In pregnant ewes, inhibition of progesterone production by trilostane during the day 5 to 16 period prevented the rise in progesterone concentrations and led to a significant increase of FOXL2 expression in caruncles compared with the control group (1.4-fold, p < 0.05). Ovariectomized ewes or cows that were supplemented with exogenous progesterone for 12 days or 6 days, respectively, had lower endometrial FOXL2 expression compared with control ovariectomized females (sheep, mRNA, 1.8-fold; protein, 2.4-fold; cattle; mRNA, 2.2-fold; p < 0.05). Exogenous oestradiol treatments for 12 days in sheep or 2 days in cattle did not affect FOXL2 endometrial expression compared with control ovariectomized females, except at the protein level in both endometrial areas in the sheep. Moreover, treating bovine endometrial explants with exogenous progesterone for 48h reduced FOXL2 expression. Using in vitro assays with COS7 cells we also demonstrated that progesterone regulates the FOXL2 promoter activity through the progesterone receptor. Collectively, our findings imply that endometrial FOXL2 is, as a direct target of progesterone, involved in early pregnancy and implantation.

scholarly journals Osteostat/Tumor Necrosis Factor Superfamily 18 Inhibits Osteoclastogenesis and Is Selectively Expressed by Vascular Endothelial Cells

Endocrinology ◽  
2006 ◽  
Vol 147 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Bernardetta Nardelli ◽  
Liubov Zaritskaya ◽  
William McAuliffe ◽  
Yansong Ni ◽  
Clint Lincoln ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Vascular Endothelial Cells ◽  
Early Stage ◽  
Osteoclast Differentiation ◽  
Precursor Cells ◽  
In Vitro Assays ◽  
Vascular Endothelial ◽  
Tnf Superfamily ◽  
And Function

Vascular endothelial cells (EC) participate in the process of bone formation through the production of factors regulating osteoclast differentiation and function. In this study, we report the selective expression in primary human microvascular EC of Osteostat/TNF superfamily 18, a ligand of the TNF superfamily. Osteostat protein is detectable in human microvascular EC and is highly up-regulated by IFN-α and IFN-β. Moreover, an anti-Osteostat antibody strongly binds to the vascular endothelium in human tissues, demonstrating that the protein is present in the EC layers surrounding blood vessels. Functional in vitro assays were used to define Osteostat involvement in osteoclastogenesis. Both recombinant and membrane-bound Osteostat inhibit differentiation of osteoclasts from monocytic precursor cells. Osteostat suppresses the early stage of osteoclastogenesis via inhibition of macrophage colony-stimulating factor-induced receptor activator of NF-κB (RANK) expression in the osteoclast precursor cells. This effect appears to be specific for the differentiation pathway of the osteoclast lineage, because Osteostat does not inhibit lipopolysaccharide-induced RANK expression in monocytes and dendritic cells, or activation-induced RANK expression in T cells. These findings demonstrate that Osteostat is a novel regulator of osteoclast generation and substantiate the major role played by the endothelium in bone physiology.

Gonadotrophin glycosylation and function

1990 ◽  
Vol 125 (1) ◽  
pp. 3-14 ◽  
Author(s):  
C. A. Wilson ◽  
A. J. Leigh ◽  
A. J. Chapman
Keyword(s):  
Life Cycle ◽  
Old Age ◽  
Gonadal Steroids ◽  
In Vitro Assays ◽  
Heterogeneous Structure ◽  
Gonadotrophin Releasing Hormone ◽  
And Function ◽  
Oligosaccharide Structures

ABSTRACT This review emphasizes the heterogeneous structure of the gonadotrophin hormones and the influence of different oligosaccharide structures on the bioactivity of these hormones. A summary has been made of the changes in biopotency of the gonadotrophins throughout the life-cycle of the human and in different endocrine states in the rat. In general it appears that the charge of the gonadotrophin conferred by the acid radicals attached to the terminal groups on the oligosaccharide structures strongly influences biopotency. Basic structures have a greater potency in in-vitro assays, but a short half-life in the circulation, while acidic isoforms are less potent, but have a longer circulatory time and are thus more active in in-vivo estimations. More basic forms are secreted over the adult reproductive years compared with the prepubertal period and old age. The glycosyl structure of the carbohydrate groups also alters in different endocrine states and is probably also important for the bioactivity and potency of the hormone. Gonadotrophin-releasing hormone (GnRH) and gonadal steroids can influence the type of isoform synthesized and released, and therefore affect the function of gonadotrophins. GnRH enhances glycosylation, sulphation and biopotency. Oestradiol potentiates the glycosylation induced by GnRH and reduces sialylation, while testosterone increases sialylation. Journal of Endocrinology (1990) 125, 3–14

Localization and function of Arf family GTPases

2005 ◽  
Vol 33 (4) ◽  
pp. 639-642 ◽  
Author(s):  
J.G. Donaldson ◽  
A. Honda
Keyword(s):  
Plasma Membrane ◽  
Membrane Trafficking ◽  
In Vitro Assays ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Multiple Regions ◽  
Sites Of Action ◽  
And Function

Arfs are a family of Ras-related GTP-binding proteins that function in the regulation of membrane trafficking and structure. The six mammalian Arf proteins are expressed ubiquitously and so it is anticipated that each will have a distinct localization and function within the cell. It has been assumed that much of this specificity will be defined by determining which regulators of Arfs, the GEFs (guanine nucleotide-exchange factors) and GAPs (GTPase-activating proteins) function with which Arf proteins. Although in vitro assays may indicate Arf preferences for the numerous Arf GEFs and GAPs that have been identified, in the cell the different Arfs, GEFs and GAPs are targeted to specific compartments where they carry out their functions. We have embarked on studies to define regions of the Arf1 and Arf6 proteins that determine their sites of action and specific activities at the Golgi and plasma membrane respectively. Chimaeras were made between Arf1 and Arf6 in order to identify regions of the protein that contributed to targeting and function. Whereas Arf6 is targeted to the plasma membrane through multiple regions along the protein, we have found a Golgi-targeting region in Arf1 that is sufficient to target Arf6 to the Golgi complex.

scholarly journals HDL Is Not Dead Yet

Biomedicines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 128
Author(s):  
Shuhui Wang Lorkowski ◽  
Jonathan D. Smith
Keyword(s):  
Reverse Cholesterol Transport ◽  
Mendelian Randomization ◽  
Density Lipoprotein ◽  
Epidemiological Studies ◽  
Structure And Function ◽  
In Vitro Assays ◽  
Cholesterol Transport ◽  
Rare Mutations ◽  
And Function

High-density lipoprotein cholesterol (HDL-C) levels are inversely correlated with coronary heart disease (CHD) in multiple epidemiological studies, but whether HDL is causal or merely associated with CHD is unclear. Recent trials for HDL-raising drugs were either not effective in reducing CHD events or, if beneficial in reducing CHD events, were not conclusive as the findings could be attributed to the drugs’ LDL-reducing activity. Furthermore, the first large Mendelian randomization study did not causally relate HDL-C levels to decreased CHD. Thus, the hypothesis that HDL is protective against CHD has been rightfully challenged. However, subsequent Mendelian randomization studies found HDL characteristics that are causally related to decreased CHD. Many aspects of HDL structure and function, especially in reverse cholesterol transport, may be better indicators of HDL’s protective activity than simply measuring HDL-C. Cholesterol efflux capacity is associated with lower levels of prevalent and incident CHD, even after adjustment for HDL-C and apolipoprotein A-1 levels. Also, subjects with very high levels of HDL-C, including those with rare mutations that disrupt hepatic HDL uptake and reverse cholesterol transport, may be at higher risk for CHD than those with moderate levels. We describe here several cell-based and cell-free in vitro assays of HDL structure and function that may be used in clinical studies to determine which of HDL’s functions are best associated with protection against CHD. We conclude that the HDL hypothesis may need revision based on studies of HDL structure and function, but that the HDL hypothesis is not dead yet.

scholarly journals Interaction Between Dax-1 and Steroidogenic Factor-1 in Vivo: Increased Adrenal Responsiveness to ACTH in the Absence of Dax-1

Endocrinology ◽  
2002 ◽  
Vol 143 (2) ◽  
pp. 665-673 ◽  
Author(s):  
Poda Suresh Babu ◽  
David L. Bavers ◽  
Felix Beuschlein ◽  
Sonalee Shah ◽  
Baxter Jeffs ◽  
...  
Keyword(s):  
In Vitro Assays ◽  
Acth Stimulation ◽  
Steroidogenic Factor 1 ◽  
Protein Levels ◽  
Cellular Hypertrophy ◽  
Acth Receptor ◽  
Adrenal Hypoplasia ◽  
And Function

Abstract Two nuclear receptors, dosage-sensitive sex reversal adrenal hypoplasia congenita, critical region on the X chromosome gene-1 (Dax-1) and steroidogenic factor-1 (SF-1), are required for adrenal development and function. In vitro assays suggest that Dax-1 represses SF-1 mediated transcription. In this study, we generated SF-1+/−: Dax-1−/Y mice to examine the role of Dax-1 in SF-1-dependent steroidogenesis in vivo. While the SF-1 expression was impaired in SF-1+/− mice, there was no change in Dax-1 expression in SF-1+/− mice and no change in SF-1 expression in Dax-1−/Y mice. SF-1+/− mice had small adrenal glands with adrenal hypoplasia and cellular hypertrophy. The loss of Dax-1 in SF-1+/−: Dax-1−/Y mice reversed the decreased adrenal weight and histological abnormalities observed in SF-1+/− mice. SF-1+/− mice had elevated ACTH and the lowest corticosterone following restraint stress. In contrast, Dax-1−/Y mice had elevated corticosterone and decreased ACTH. Adrenal responsiveness (ACTH/corticosterone) was highest in Dax-1−/Y mice, intermediate in WT and SF-1+/−: Dax-1−/Y mice, and lowest in SF-1+/− mice. In accordance with these findings, ACTH stimulation testing resulted in the highest levels of corticosterone in the Dax-1−/Y mice. Protein levels of P450c21 and the ACTH receptor were increased in Dax-1−/Y mice and intermediate in SF-1+/−: Dax-1−/Y mice following chronic food deprivation. These results are consistent with a model in which Dax-1 functions to inhibit SF-1-mediated steroidogenesis in vivo.

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