bims-meglyc 2023-08-06 papers

Cell Rep Methods. 2023 Jul 24. 3(7): 100518

Enzymatic assay for UDP-GlcNAc and its application in the parallel assessment of substrate availability and protein O-GlcNAcylation.

Marc Sunden, Divya Upadhyay, Rishi Banerjee, Nina Sipari, Vineta Fellman, Jukka Kallijärvi, Janne Purhonen.

O-linked N-acetylglucosaminylation (O-GlcNAcylation) is a ubiquitous and dynamic non-canonical glycosylation of intracellular proteins. Several branches of metabolism converge at the hexosamine biosynthetic pathway (HBP) to produce the substrate for protein O-GlcNAcylation, the uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). Availability of UDP-GlcNAc is considered a key regulator of O-GlcNAcylation. Yet UDP-GlcNAc concentrations are rarely reported in studies exploring the HBP and O-GlcNAcylation, most likely because the methods to measure it are restricted to specialized chromatographic procedures. Here, we introduce an enzymatic method to quantify cellular and tissue UDP-GlcNAc. The method is based on O-GlcNAcylation of a substrate peptide by O-linked N-acetylglucosamine transferase (OGT) and subsequent immunodetection of the modification. The assay can be performed in dot-blot or microplate format. We apply it to quantify UDP-GlcNAc concentrations in several mouse tissues and cell lines. Furthermore, we show how changes in UDP-GlcNAc levels correlate with O-GlcNAcylation and the expression of OGT and O-GlcNAcase (OGA).

Keywords: GlcNAc salvage pathway; O-GlcNAcase; O-linked N-acetylglucosamine transferase; OGA; OGT; hexosamine biosynthetic pathway; microplate assay for UDP-GlcNAc; nucleotide sugars; protein O-GlcNAcylation homeostasis

DOI: https://doi.org/10.1016/j.crmeth.2023.100518

Clin Ther. 2023 Jul 28. pii: S0149-2918(23)00204-7. [Epub ahead of print]

Advancing Understanding of Inequities in Rare Disease Genomics.

Jillian G Serrano, Melanie O'Leary, Grace E VanNoy, Brian E Mangilog, Ingrid A Holm, Yarden S Fraiman, Heidi L Rehm, Anne O'Donnell-Luria, Monica H Wojcik.

PURPOSE: Advances in genomic research have facilitated rare disease diagnosis for thousands of individuals. Unfortunately, the benefits of advanced genetic diagnostic technology are not distributed equitably among the population, as has been seen in many other health care contexts. Quantifying and describing inequities in genetic diagnostic yield is inherently challenging due to barriers to both clinical and research genetic testing. We therefore present an implementation protocol developed to expand access to our rare disease genomic research study and to further understand existing inequities.
METHODS AND FINDINGS: The Rare Genomes Project (RGP) at the Broad Institute of MIT and Harvard offers research genome sequencing to individuals with rare disease who remain genetically undiagnosed through direct interaction with the individual or family. This presents an opportunity for diagnosis beyond the clinical context, thus eliminating many barriers to access. An initial goal of RGP was to equalize access to genomic sequencing by decoupling testing access from proximity to a major medical center and physician referral. However, study participants over the initial 3 years of this project were predominantly white and well resourced. To further understand and address the lack of diversity within RGP, we developed a novel protocol embedded within the larger RGP study, in an approach informed by an implementation science framework. The aims of this protocol were: (1) to diversify recruitment and enrollment within RGP; (2) understand the process and context of implementing genomic medicine for rare disease diagnosis; and (3) investigate the value of a diagnosis for underserved populations.
IMPLICATIONS: Improved understanding of existing inequities and potential strategies to address them are needed to advance equity in rare disease genetic diagnosis and research. In addition to the moral imperative of equity in genomic medicine, this approach is critical in order to fully understand the genomic underpinnings of rare disease.

Keywords: Disparities; Genetics; Genomics; Implementation; Inequities; Rare disease

DOI: https://doi.org/10.1016/j.clinthera.2023.06.010

Bioorg Med Chem. 2023 Jul 06. pii: S0968-0896(23)00254-7. [Epub ahead of print]92 117406

Glycogen synthase kinase-3: A potential target for diabetes.

Divya M Teli, Anuradha K Gajjar.

Elevated circulating glucose level due to β-cell dysfunction has been a key marker of Type-II diabetes. Glycogen synthase kinase-3 (GSK-3) has been recognized as an enzyme involved in the control of glycogen metabolism. Consequently, inhibitors of GSK-3 have been explored for anti-diabetic effects in vitro and in animal models. Further, the mechanisms governing the regulation of this enzyme have been elucidated by means of a combination of structural and cellular biological investigations. This review article examines the structural analysis of GSK-3 as well as molecular modeling reports from numerous researchers in the context of the design and development of GSK-3 inhibitors. This article centers on the signaling pathway of GSK-3 relevant to its potential as a target for diabetes and discusses advancements till date on different molecular modification approaches used by researchers in the development of novel GSK-3 inhibitors as potential therapeutics for the treatment of Type II diabetes.

Keywords: Diabetes; Glycogen metabolism; Glycogen synthase kinase-3; Inhibitors

DOI: https://doi.org/10.1016/j.bmc.2023.117406