Dr inż. Anna Drzazga’s research project called Dietary intake and human gut microbiome as sources of N-acylated amines activating G-protein-coupled receptors (GPCRs) (Dieta i ludzki mikrobiom jelitowy jako źródła N-acylowanych amin będących ligandami receptorów GPCR) included a six-month fellowship at the Department of Biomedical Sciences at the University of Copenhagen. She has continued her collaboration with this renowned research center by taking part in research spanning biotechnology, pharmacology and food science.
Below, the author of the grant-winning proposal shares her thoughts on her NCN-funded research conducted at the Danish university.
Diabetes - a 21st century pandemic
The International Diabetes Federation data for 2021 indicated that more than 530 million people suffer from diabetes, including 2.5 million Poles. Equally bleak are the predictions of how this 21st century pandemic could be decelerated in the next 20 years. Accordingly, there is a pressing need to develop new strategies for early detection and treatment of diabetes and to identify bioactive dietary components that regulate glucose metabolism and stimulate insulin secretion.
How the NAAs play a role in the pursuit of new approaches to tackle diabetes
The Sonatina grant research is designed to gauge the potential antidiabetic properties of N-acylated amines (NAAs) as substances capable of regulating glucose homeostasis by activating certain proteins known as G-protein-coupled receptors (GPCRs).
NAAs produced by the human gastrointestinal microbiome bacteria have recently been found to be able to activate one of these proteins, the GPR119 receptor. Now it is considered one of the main therapeutic targets in the search for new anti-diabetic strategies. Activation of GPR119 is associated with, among other things, stimulation of insulin secretion and reduction of blood glucose levels.
NAAs represent an extensive, functionally diverse class of signaling molecules produced by the bacteria that make up the gut microbiota but, independently, are also present in dietary oils ( e.g., olive oil, canola oil). In terms of their chemical structure, NAAs resemble other endogenous chemicals that activate the GPR119 receptor - oleoylethanolamide and 2-oleoyl glycerol (2-OG).
It is worth noting that previous studies by dr inż. Drzazga established that lysophosphatidylcholines (LPC) can activate the GPR119 receptor as well as two other receptors, GPR40 and GPR55, which together mediate the modulation of insulin secretion under high glucose (GSIS) conditions. These results led to the hypothesis that NAAs can also activate more than one receptor involved in maintaining carbohydrate homeostasis.
The overarching objective of the project was to test the hypothesis of the activity of NAAs produced by commensal bacteria and available in the diet with respect to a broader group of receptors (not just GPR119). That goal has already largely been accomplished over the course of the project by determining the content of structurally diverse NAAs in dietary oils and those produced by intestinal bacteria.
That phase of the project was carried out in cooperation with professor Przemyslaw Bernat of the Department of Industrial Microbiology and Biotechnology at UŁ and professor Adriana Nowak of the Department of Environmental Biotechnology at TUL.
The next stage, namely research on animal and human cell lines representing pancreatic β cells that produce insulin and intestinal L cells that produce glucagon-like peptide 1 (GLP-1), was carried out at my home institute at TUL.
Collaboration with the Danish University
An important part of the Sonatina grant was the six-month fellowship at the Department of Biomedical Sciences at the University of Copenhagen in professor Mette Rosenkilde's Group. The group are the world's foremost experts on GPCR receptors and their involvement in the regulation of metabolic processes. On account of the successive COVID-19 surges, the trip to Copenhagen had to be postponed several times, but in March 2022 the trip to Denmark came true.
The fellowship not only extended the range of research methods used, but laid the groundwork for further long-term collaboration. The relations have been further strengthened by collaborative preparation of publications and the upcoming ERNEST (the European Research Network for Signal Transduction) conference, which will focus on the structure and function of GPCR receptors. The conference will convene in early May 2023 in Greece, where the results of research conducted at both the University of Copenhagen and Lodz University of Technology are to be presented.
The research currently continued in Denmark, apart from further work under the Sonatina grant, is devoted to lipid and viral receptors. The advanced research methods allow us to, among other things, map in real time the signaling pathways associated with various G proteins, monitor receptor internalization dependent and independent of β-arestins, identify the affinity of ligands to membrane receptors using radiolabeled ligands, generate cell lines expressing a single receptor or several receptors in different ratios, etc. On the other hand, animal tissue (e.g., mouse pancreatic islets) is used in ex vivo studies that are also in progress. The results of the experiments conducted not only complete the picture of the biological activity of NAAs available in the diet as molecules regulating carbohydrate metabolism, but also bring much new information about the pharmacology of the interactions of these compounds with membrane receptors.