Jingwen Xu1, Duoling Li1, Jingwei Lv1, Xuebi Xu1, Bing Wen1, Pengfei Lin1, Fuchen Liu1,2, Kunqian Ji1, Jingli Shan1, Honghao Li1, Wei Li1, Yuying Zhao1, Dandan Zhao1, Joo Y Pok3, Chuanzhu Yan1,4,5. 1. Research Institute of Neuromuscular and Neurodegenerative Disease, Department of Neurology, Qilu Hospital, Shandong University, Jinan, China. 2. Department of Neurobiology, Yale University School of Medicine, New Haven, CT. 3. Department of Neurology, Yale University, New Haven, CT. 4. Brain Science Research Institute, Shandong University, Jinan, China. 5. Laboratory of Mitochondrial Medicine, Qilu Hospital (Qingdao), Qingdao, China.
Abstract
OBJECTIVE: Riboflavin-responsive multiple acyl-coenzyme A dehydrogenation deficiency (RR-MADD) is an inherited fatty acid metabolism disorder mainly caused by genetic defects in electron transfer flavoprotein-ubiquinone oxidoreductase (ETF:QO). The variant ETF:QO protein folding deficiency, which can be corrected by therapeutic dosage of riboflavin supplement, has been identified in HEK-293 cells and is believed to be the molecular mechanism of this disease. To verify this hypothesis in vivo, we generated Etfdh (h)A84T knockin (KI) mice. METHODS: Tissues from these mice as well as muscle biopsies and fibroblasts from 7 RR-MADD patients were used to examine the flavin adenine dinucleotide (FAD) concentration and ETF:QO protein amount. RESULTS: All of the homozygous KI mice (Etfdh (h)A84T/(h)A84T , KI/KI) were initially normal. After being given a high-fat and vitamin B2 -deficient (HF-B2 D) diet for 5 weeks, they developed weight loss, movement ability defects, lipid storage in muscle and liver, and elevated serum acyl-carnitine levels, which are clinically and biochemically similar to RR-MADD patients. Both ETF:QO protein and FAD concentrations were significantly decreased in tissues of HF-B2 D-KI/KI mice and in cultured fibroblasts from RR-MADD patients. After riboflavin treatment, ETF:QO protein increased in proportion to elevated FAD concentrations, but not related to mRNA levels. These results were further confirmed in cultured fibroblasts from RR-MADD patients. INTERPRETATION: For the first time, we successfully developed a RR-MADD mice model and confirmed that FAD homeostasis disturbances played a crucial role on the pathomechanism of RR-MADD in this mouse model and culture cells from patients. Supplementation of riboflavin may stabilize variant ETF:QO protein by rebuilding FAD homeostasis. Ann Neurol 2018;84:667-681.
OBJECTIVE:Riboflavin-responsive multiple acyl-coenzyme A dehydrogenation deficiency (RR-MADD) is an inherited fatty acid metabolism disorder mainly caused by genetic defects in electron transfer flavoprotein-ubiquinone oxidoreductase (ETF:QO). The variant ETF:QO protein folding deficiency, which can be corrected by therapeutic dosage of riboflavin supplement, has been identified in HEK-293 cells and is believed to be the molecular mechanism of this disease. To verify this hypothesis in vivo, we generated Etfdh (h)A84T knockin (KI) mice. METHODS: Tissues from these mice as well as muscle biopsies and fibroblasts from 7 RR-MADDpatients were used to examine the flavin adenine dinucleotide (FAD) concentration and ETF:QO protein amount. RESULTS: All of the homozygous KI mice (Etfdh (h)A84T/(h)A84T , KI/KI) were initially normal. After being given a high-fat and vitamin B2 -deficient (HF-B2 D) diet for 5 weeks, they developed weight loss, movement ability defects, lipid storage in muscle and liver, and elevated serum acyl-carnitine levels, which are clinically and biochemically similar to RR-MADDpatients. Both ETF:QO protein and FAD concentrations were significantly decreased in tissues of HF-B2 D-KI/KI mice and in cultured fibroblasts from RR-MADDpatients. After riboflavin treatment, ETF:QO protein increased in proportion to elevated FAD concentrations, but not related to mRNA levels. These results were further confirmed in cultured fibroblasts from RR-MADDpatients. INTERPRETATION: For the first time, we successfully developed a RR-MADDmice model and confirmed that FAD homeostasis disturbances played a crucial role on the pathomechanism of RR-MADD in this mouse model and culture cells from patients. Supplementation of riboflavin may stabilize variant ETF:QO protein by rebuilding FAD homeostasis. Ann Neurol 2018;84:667-681.
Authors: Piero Leone; Maria Tolomeo; Elisabetta Piancone; Pier Giorgio Puzzovio; Carla De Giorgi; Cesare Indiveri; Elia Di Schiavi; Maria Barile Journal: IUBMB Life Date: 2021-09-24 Impact factor: 4.709