• Home
  • Search Results
  • Enhanced endoplasmic reticulum stress in bone marrow angiogenic progenitor cells in a mouse model of long-term experimental type 2 diabetes.

Enhanced endoplasmic reticulum stress in bone marrow angiogenic progenitor cells in a mouse model of long-term experimental type 2 diabetes.

Diabetologia (2015-06-13)
Maulasri Bhatta, Jacey Hongjie Ma, Joshua J Wang, Jonna Sakowski, Sarah X Zhang
ABSTRACT

Bone marrow-derived circulating angiogenic cells (CACs) play an important role in vascular repair. In diabetes, compromised functioning of the CACs contributes to the development of diabetic retinopathy; however, the underlying mechanisms are poorly understood. We examined whether endoplasmic reticulum (ER) stress, which has recently been linked to endothelial injury, is involved in diabetic angiogenic dysfunction. Flow cytometric analysis was used to quantify bone marrow-derived progenitors (Lin(-)/c-Kit(+)/Sca-1(+)/CD34(+)) and blood-derived CACs (Sca-1(+)/CD34(+)) in 15-month-old Lepr (db) (db/db) mice and in their littermate control (db/+) mice used as a model of type 2 diabetes. Markers of ER stress in diabetic (db/db) and non-diabetic (db/+) bone marrow-derived early outgrowth cells (EOCs) and retinal vascular density were measured. The numbers of bone-marrow progenitors and CACs were significantly reduced in db/db mice. Vascular density was markedly decreased in the retinas of db/db mice, and this was accompanied by vascular beading. Microglial activation was enhanced, as was the production of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). The production of ER stress markers (glucose-regulated protein-78 [GRP-78], phosphorylated inositol-requiring enzyme-1α [p-IRE-1α], phosphorylated eukaryotic translation initiation factor-2α [p-eIF2α], activating transcription factor-4 [ATF4], C/EBP homologous protein [CHOP] and spliced X-box binding protein-1 [XBP1s]) was significantly increased in bone marrow-derived EOCs from db/db mice. In addition, mouse EOCs cultured in high-glucose conditions demonstrated higher levels of ER stress, reduced colony formation, impaired migration and increased apoptosis, all of which were largely prevented by the chemical chaperone 4-phenylbutyrate. Taken together, our results indicate that diabetes increases ER stress in bone marrow angiogenic progenitor cells. Thus, targeting ER stress may offer a new approach to improving angiogenic progenitor cell function and promoting vascular repair in diabetes.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Ascorbic acid, 99%
Sigma-Aldrich
D-Mannitol, ≥98%
Sigma-Aldrich
L-Ascorbic acid, powder, suitable for cell culture, γ-irradiated
Sigma-Aldrich
L-Ascorbic acid, BioXtra, ≥99.0%, crystalline
Sigma-Aldrich
L-Ascorbic acid, suitable for cell culture, suitable for plant cell culture, ≥98%
Sigma-Aldrich
L-Ascorbic acid, ACS reagent, ≥99%
Sigma-Aldrich
D-Mannitol, ACS reagent
Sigma-Aldrich
L-Ascorbic acid, reagent grade, crystalline
Sigma-Aldrich
L-(−)-Glucose, ≥99%
Sigma-Aldrich
D-Mannitol, meets EP, FCC, USP testing specifications
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ACS reagent, reag. ISO, Ph. Eur., 99.7-100.5% (oxidimetric)
Sigma-Aldrich
D-Mannitol, BioXtra, ≥98% (HPLC)
Sigma-Aldrich
D-Mannitol, suitable for plant cell culture
Sigma-Aldrich
L-Ascorbic acid, reagent grade
Sigma-Aldrich
L-Ascorbic acid, meets USP testing specifications
Sigma-Aldrich
L-Ascorbic acid, FCC, FG
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ≥99.0% (RT)
Sigma-Aldrich
L-Ascorbic acid, BioUltra, ≥99.5% (RT)
Sigma-Aldrich
D-Mannitol, BioUltra, ≥99.0% (sum of enantiomers, HPLC)
Sigma-Aldrich
L-Ascorbic acid, suitable for plant cell culture