title: Insulin therapy for pre-hyperglycemic beta-cell endoplasmic reticulum crowding.
abstract: Insulin therapy improves β-cell function in early stages of diabetes by mechanisms that may exceed alleviation of glucotoxicity. In advance type 2 diabetes, hyperglycemia causes β-cell damage and ultimately β-cell loss. At such an advanced stage, therapeutic modalities are often inadequate. Growing evidence indicates that in early stages of type-2 diabetes and some types of monogenic diabetes linked with malfunctioning endoplasmic-reticulum (ER), the β-cell ER fails to process sufficient proinsulin once it becomes overloaded. These changes manifest with ER distention (ER-crowding) and deficiency of secretory granules. We hypothesize that insulin therapy may improves β-cell function by alleviating ER-crowding. To support this hypothesis, we investigated pre-diabetic β-cell changes in hProC(A7)Y-CpepGFP transgenic mice that develop prolonged pre-diabetes due to proinsulin dysmaturation and ER-crowding. We attenuated the β-cell ER proinsulin synthesis with a treat-to-target insulin therapy while avoiding hypoglycemia and weight gain. Alleviation of ER-crowding resulted in temporary improvement in proinsulin maturation, insulin secretion and glucose tolerance. Our observations suggest that alleviation of pre-diabetic ER-crowding using a treat-to-target insulin therapy may improve β-cell function and may prevent further metabolic deterioration.
authors: Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
authors: Afaf
authors: A
authors: Absood
authors: Benjamin
authors: B
authors: Gandomani
authors: Anthony
authors: A
authors: Zaki
authors: Vlad
authors: V
authors: Nasta
authors: Andrew
authors: A
authors: Michail
authors: Peter M W
authors: PM
authors: Habib
authors: Israel
authors: I
authors: Hodish
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004721:Endoplasmic Reticulum / Q000187:drug effects*; D007150:Immunohistochemistry; D007328:Insulin / Q000494:pharmacology / Q000627:therapeutic use*; D007515:Islets of Langerhans / Q000187:drug effects*; D051379:Mice; D008822:Mice, Transgenic; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D007328:Insulin