O-GlcNAc regulates the mitochondrial integrated stress response by regulating ATF4.

Background: Accumulation of mitochondrial dysfunctional is a hallmark of age-related neurodegeneration including Alzheimer's disease (AD). Impairment of mitochondrial quality control mechanisms leading to the accumulation of damaged mitochondria and increasing neuronal stress. Therefore, investigating the basic mechanisms of how mitochondrial homeostasis is regulated is essential.

O-GlcNAcylation regulates extracellular signal-regulated kinase (ERK) activation in Alzheimer's disease.

Introduction: Aberrant activation of Extracellular Signal-Regulated Kinase (ERK) signaling is associated with Alzheimer's disease (AD) pathogenesis. For example, enhanced ERK signal activation mediated by Apolipoprotein E4 (APOE4), which is a critical genetic risk factor for AD, increases the transcription of amyloid precursor protein (APP). We hypothesize that O-linked N-acetylglucosamine (O-GlcNAc) regulates the phosphorylation and activation of ERK.

Symptoms Suggestive of Postpulmonary Embolism Syndrome and Utilization of Diagnostic Testing.

Background: Persistent symptoms of chest pain, dyspnea, fatigue, lightheadedness, and/or syncope more than 3 months after an acute pulmonary embolism (PE) are collectively classified as postpulmonary embolism syndrome (PPES). Although PPES is increasingly recognized as an important long-term sequel of acute PE, its contemporary incidence is unclear. Furthermore, the utilization of diagnostic testing for further phenotypic characterization of these patients is unknown.

The Role of O-GlcNAcylation in Immune Cell Activation.

O-GlcNAcylation is a dynamic post-translational modification where the sugar, O-linked β-N-acetylglucosamine (O-GlcNAc) is added to or removed from various cytoplasmic, nuclear, and mitochondrial proteins. This modification is regulated by only two enzymes: O-GlcNAc transferase (OGT), which adds O-GlcNAc, and O-GlcNAcase (OGA), which removes the sugar from proteins. O-GlcNAcylation is integral to maintaining normal cellular function, especially in processes such as nutrient sensing, metabolism, transcription, and growth and development of the cell.

OGA Inhibition Alters Energetics and Nutrient Sensing in Alzheimer's Disease Cytoplasmic Hybrids.

Background: Alzheimer's disease (AD) features reductions in key bioenergetic fluxes and perturbed mitochondrial function. Cytoplasmic hybrids (cybrids) generated through the transfer of AD subject mitochondria to mtDNA-depleted SH-SY5Y neuroblastoma cells recapitulate some of these features in an in vitro setting.

Objective: For this study, we used the AD cybrid model to assess the impact of a nutrient-excess like-state via increasing O-GlcNAcylation on whole cell and mitochondrial homeostasis.