Project Details
Projekt
Therapeutic targeting of hexokinase in intestinal inflammation
Applicant
Privatdozent Felix Sommer, Ph.D.
Subject Area
Gastroenterology
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 426660215
Inflammation is characterized by changes in metabolic activity, in particular glucose metabolism. Hexokinase (HK) catalyzes the first step of glycolysis and thereby contributes to crucial homeostatic body functions. Mammals encode five HK isoenzymes: HK1-4 and HKDC1 (HK domain containing 1). HK2 is of particular interest, as it is the most abundant HK in the intestine, exerts high HK activity, and responds to various stimuli including the microbiome. During phase I of miTarget, we found that HK2 expression is upregulated in the inflamed mucosa of patients with intestinal inflammation and that ablation of HK2 in intestinal epithelial cells (IEC) protects from colitis, suppresses cell death and alters mitochondrial function. We further revealed that the microbial metabolite butyrate inhibits HK2 expression by signaling through histone deacetylase 8 (HDAC8) and thereby protects from acute inflammation. We now aim to build upon these findings by elucidating the precise molecular mechanism how HK2-inhibition protects from inflammation, investigating the transcriptional regulatory landscape how the microbiome controls HK2 via butyrate and HDAC8, and testing newly identified specific HK2 inhibitors as well as pro- and prebiotics for their potential to modulate colitis susceptibility in mice as trials with butyrate in IBD patients had to be discontinued due to side-effects related to its chemical nature. To those ends, we will profile the HK2-dependent functional mitochondrial alterations in two complementary in vitro models - Caco-2 cells and intestinal organoids – by metabolic tracing experiments using 13C glucose, Seahorse analyses, mitochondrial permeability transition pore (MPTP) assays, tetramethylrhodamine methyl ester (TMRM) staining, cytochrome c release measurements, and anti-HK2 immunoprecipitation. We will further perform HDAC8 ChIP-seq and Hk2 promoter bait fishing for transcription factors, and we will treat WT and HK2∆IEC mice with novel HK2 inhibitors or selected probiotic bacteria and prebiotic substances to identify alternatives to butyrate to be used in a future clinical trial. Together, these experiments promise to reveal druggable molecular targets in the microbiome-HK2 axis that then can be translated into the clinic to treat intestinal inflammation.
DFG Programme
Research Units
