Implication of altered ubiquitin-proteasome system and ER stress in the muscle atrophy of diabetic rats
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
Authors: Reddy, S. Sreenivasa; Shruthi, Karnam; Prabhakar, Y. Konda; Sailaja, Gummadi; Reddy, G. Bhanuprakash
Abstract
Background: Skeletal muscle is adversely affected in type-1 diabetes, and excessively stimulated ubiquitin-proteasome system (UPS) was found to be a leading cause of muscle wasting or atrophy. The role of endoplasmic reticulum (ER) stress in muscle atrophy of type-1 diabetes is not known. Hence, we investigated the role of UPS and ER stress in the muscle atrophy of chronic diabetes rat model. Methods: Diabetes was induced with streptozotocin (STZ) in male Sprague-Dawley rats and were sacrificed 2- and 4-months thereafter to collect gastrocnemius muscle. In another experiment, 2-months post-STZ-injection diabetic rats were treated with MG132, a proteasome inhibitor, for the next 2-months and gastrocnemius muscle was collected. Results: The muscle fiber cross-sectional area was diminished in diabetic rats. The expression of UPS components: El, MURF1, TRIM72, UCHL1, UCHL5, ubiquitinated proteins, and proteasome activity were elevated in the diabetic rats indicating activated UPS. Altered expression of ER-associated degradation (ERAD) components and increased ER stress markers were detected in 4-months diabetic rats. Proteasome inhibition by MG132 alleviated alterations in the UPS and ER stress in diabetic rat muscle. Conclusion: Increased UPS activity and ER stress were implicated in the muscle atrophy of diabetic rats and proteasome inhibition exhibited beneficiary outcome.
A MID1 Gene Mutation in a Patient With Opitz G/BBB Syndrome That Altered the 3D Structure of SPRY Domain
AMERICAN JOURNAL OF MEDICAL GENETICS PART A
Authors: Hu, Ching-Hsuan; Liu, Yu-Fan; Yu, Ju-Shan; Ng, Yan-Yan; Chen, Suh-Jen; Su, Pen-Hua; Chen, Jia-Yuh
Abstract
Mutations in the MID1 gene result in X-linked Opitz G/BBB syndrome (OS), a disorder that affects development of midline structures and comprises hypertelorism, cleft lip/palate, hypospadias, and laryngo-tracheo-esophageal abnormalities, and, at times, neurological, anal, and cardiac defects. MID1 gene abnormalities include missense, nonsense, and splicing mutations, small insertions, small deletions, and complex rearrangements. Here, we present a patient with Opitz G/BBB syndrome and a unique MID1 gene point mutation c.1703T