Intracellular MLCK1 diversion reverses barrier loss to restore mucosal homeostasis

• Published in: Nature medicine Vol. 25; no. 4; pp. 690 - 700
• Main Authors: Graham, W Vallen, He, Weiqi, Marchiando, Amanda M, Zha, Juanmin, Singh, Gurminder, Li, Hua-Shan, Biswas, Amlan, Ong, Ma Lora Drizella M, Jiang, Zhi-Hui, Choi, Wangsun, Zuccola, Harmon, Wang, Yitang, Griffith, James, Wu, Jingshing, Rosenberg, Harry J, Wang, Yingmin, Snapper, Scott B, Ostrov, David, Meredith, Stephen C, Miller, Lawrence W, Turner, Jerrold R
• Format: Journal Article
• Language: English
• Published: United States Nature Publishing Group 01.04.2019
• Subjects: Actomyosin; Actomyosin - metabolism; Alternative splicing; Animals; Biocompatibility; Caco-2 Cells; Care and treatment; Chains; Chronic Disease; Development and progression; Diarrhea; Disease; Enzymes; Gastrointestinal diseases; Homeostasis; Homeostasis - drug effects; Humans; Inflammation - pathology; Inflammatory bowel diseases; Inflammatory Bowel Diseases - pathology; Inhibition; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; Intestine; Intracellular Space - enzymology; Jejunum - drug effects; Jejunum - metabolism; Jejunum - pathology; Kinases; Mice; Mucosa; Muscle proteins; Myosin; Myosin Light Chains - metabolism; Myosin-light-chain kinase; Myosin-Light-Chain Kinase - chemistry; Myosin-Light-Chain Kinase - metabolism; Necrosis; Novels; Phosphorylation; Phosphorylation - drug effects; Protein Domains; Recruitment; Screens; Small Molecule Libraries - pharmacology; Therapeutic applications; Tight Junctions - drug effects; Tight Junctions - metabolism; Toxicity; Tumor necrosis factor; Tumor Necrosis Factor-alpha - pharmacology; Tumor necrosis factor-TNF; Tumors
• ISSN: 1078-8956; 1546-170X
• DOI: 10.1038/s41591-019-0393-7

Epithelial barrier loss is a driver of intestinal and systemic diseases. Myosin light chain kinase (MLCK) is a key effector of barrier dysfunction and a potential therapeutic target, but enzymatic inhibition has unacceptable toxicity. Here, we show that a unique domain within the MLCK splice variant MLCK1 directs perijunctional actomyosin ring (PAMR) recruitment. Using the domain structure and multiple screens, we identify a domain-binding small molecule (divertin) that blocks MLCK1 recruitment without inhibiting enzymatic function. Divertin blocks acute, tumor necrosis factor (TNF)-induced MLCK1 recruitment as well as downstream myosin light chain (MLC) phosphorylation, barrier loss, and diarrhea in vitro and in vivo. Divertin corrects barrier dysfunction and prevents disease development and progression in experimental inflammatory bowel disease. Beyond applications of divertin in gastrointestinal disease, this general approach to enzymatic inhibition by preventing access to specific subcellular sites provides a new paradigm for safely and precisely targeting individual properties of enzymes with multiple functions.