Biology subjects

Steinberg, G. R.

Publications and source records attributed to Steinberg, G. R..

3 recordsLinked to original sources

bioRxiv2026

An Integrated Pipeline for Cell-Type Annotation, Metabolic Profiling, and Spatial Communication Analysis in the Liver using Spatial Transcriptomics

The liver acts as a central metabolic hub, integrating systemic signals through a spatially organized pattern known as zonation, driven by the coordinated activity of diverse cell types including hepatocytes, stellate cells, Kupffer cells, endothelial cells, and immune populations. Spatial transcriptomics (ST) enables the profiling of thousands of cells with spatial resolution in a single experiment, facilitating the identification of novel gene markers, cell types, cellular states, and tissue neighborhoods across diverse tissues and organisms. By simultaneously capturing transcriptional and spatial heterogeneity, ST has become a powerful tool for understanding cellular and tissue biology. Given its advantages, there is growing demand for applying ST to uncover novel biological insights in the liver under various physiological and pathological conditions including obesity, diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD). However, to date no comprehensive and practical protocols currently exist for analyzing ST data specifically in the context of liver metabolism. Herein, we present a systematic and detailed protocol for ST data analysis using liver tissues from MASLD mouse models. This guide offers practical support for metabolic based researchers without advanced expertise in coding, mathematics and statistics enabling single-cell RNA-seq referencing for deconvolution-based annotation, curated liver cell type markers for manual annotation, and a GMT file of metabolic gene sets and flux balance analysis to analyze liver metabolic activity. This framework and integrated computational resources for decoding metabolic reprogramming and cellular heterogeneity will empower researchers to uncover novel biological pathways regulating liver metabolism in health and disease.

bioinformatics↗

bioRxiv2022

High-fructose feeding suppresses cold-stimulated brown adipose tissue glucose uptake in young men independently of changes in thermogenesis and the gut microbiome

Diets rich in added sugars, especially high in fructose, are associated with metabolic diseases such as insulin resistance, and non-alcoholic fatty liver disease. Studies have shown a link between these pathologies and changes in the microbiome and its metabolites. Given the reported associations in animal models between the microbiome and brown or beige adipose tissue (BAT) function, and the alterations in the microbiome induced by high glucose or high fructose diets, we investigated the potential causal link between high glucose or fructose diets and BAT dysfunction in humans. We show that BAT glucose uptake, but not thermogenesis, is impaired by a high fructose but not high glucose diet, in the absence of changes in body mass, the gastrointestinal microbiome, and faecal short-chain fatty acids. We conclude that BAT metabolic dysfunction occurs independently from changes in gut microbiome composition, and earlier than other pathophysiological abnormalities associated with insulin resistance and dyslipidemia during fructose overconsumption in humans.

physiology↗

bioRxiv2021

Compound- and fiber type-selective requirement of AMPKγ3 for insulin-independent glucose uptake in skeletal muscle

Objective: The metabolic master-switch AMP-activated protein kinase (AMPK) mediates insulin-independent glucose uptake in muscle and regulates the metabolic activity of brown and beige adipose tissue (BAT). The regulatory AMPK{gamma}3 isoform is uniquely expressed in skeletal muscle and also potentially in BAT. Here, we investigated the role that AMPK{gamma}3 plays in mediating skeletal muscle glucose uptake and whole-body glucose clearance in response to small-molecule activators that act on AMPK via distinct mechanisms. We also assessed if {gamma}3 plays a role in adipose thermogenesis and browning. Methods: Global AMPK{gamma}3 knockout (KO) mice were generated. A systematic whole-body, tissue and molecular phenotyping linked to glucose homeostasis was performed in {gamma}3 KO and wild type (WT) mice. Glucose uptake in glycolytic and oxidative skeletal muscle ex vivo, as well as blood glucose clearance in response to small molecule AMPK activators that target nucleotide-binding domain of {gamma} subunit (AICAR) and allosteric drug and metabolite (ADaM) site located at the interface of the and {beta} subunit (991, MK-8722) were assessed. Oxygen consumption, thermography, and molecular phenotyping with a {beta}3-adrenergic receptor agonist (CL-316,243) treatment were performed to assess BAT thermogenesis, characteristics and function. Results: Genetic ablation of {gamma}3 did not affect body weight, body composition, physical activity, and parameters associated with glucose homeostasis under chow or high fat diet. {gamma}3 deficiency had no effect on fiber-type composition, mitochondrial content and components, or insulin-stimulated glucose uptake in skeletal muscle. Glycolytic muscles in {gamma}3 KO mice showed a partial loss of AMPK2 activity, which was associated with reduced levels of AMPK2 and {beta}2 subunit isoforms. Notably, {gamma}3 deficiency resulted in a selective loss of AICAR-, but not MK-8722-induced blood glucose-lowering in vivo and glucose uptake specifically in glycolytic muscle ex vivo. We detected {gamma}3 in BAT and found that it preferentially interacts with 2 and {beta}2. We observed no differences in oxygen consumption, thermogenesis, morphology of BAT and inguinal white adipose tissue (iWAT), or markers of BAT activity between WT and {gamma}3 KO mice. Conclusions: These results demonstrate that {gamma}3 plays a key role in mediating AICAR- but not ADaM site binding drug-stimulated blood glucose clearance and glucose uptake specifically in glycolytic skeletal muscle. We also showed that {gamma}3 is dispensable for thermogenesis and browning of iWAT.

physiology↗