Effects of decreased insulin-like growth factor-1 stimulation on hypoxia inducible factor 1-α protein synthesis and function during cutaneous repair in diabetic mice

2007 ◽  
Vol 15 (5) ◽  
pp. 628-635 ◽  
Author(s):  
Diana H. Yu ◽  
Kimberly A. Mace ◽  
Scott L. Hansen ◽  
Nancy Boudreau ◽  
David M. Young
2013 ◽  
Vol 25 (2) ◽  
pp. 343 ◽  
Author(s):  
Rina Meidan ◽  
Eyal Klipper ◽  
Yulia Zalman ◽  
Ronit Yalu

The hypoxic microenvironment that occurs in fast-growing tissue such as the corpus luteum (CL) is a major contributor to its ability to survive via the induction of an intricate vascular network. Cellular responses to hypoxia are mediated by hypoxia-inducible factor-1 (HIF-1), an oxygen-regulated transcriptional activator. HIF-1, a heterodimer consisting of a constitutively-expressed β subunit and an oxygen-regulated α subunit, binds to the hypoxia responsive element (HRE) present in the promoter regions of responsive genes. This review summarises evidence for the involvement of hypoxia and HIF-1α in CL development and function. Special emphasis is given to hypoxia-induced, luteal cell-specific expression of multiple genes (vascular endothelial growth factor A (VEGFA), fibroblast growth factor 2 (FGF-2), prokineticin receptor 2 (PK-R2), stanniocalcin 1 (STC-1) and endothelin 2 (EDN-2) that participate in the angiogenic process during CL formation.


2006 ◽  
Vol 26 (3) ◽  
pp. 1142-1155 ◽  
Author(s):  
Shingo Kajimura ◽  
Katsumi Aida ◽  
Cunming Duan

ABSTRACT Insulin-like growth factor binding protein 1 (IGFBP-1) is a hypoxia-inducible gene that plays an important role in regulating embryonic growth and development under hypoxic stress. The molecular mechanisms underlying hypoxia-induced IGFBP-1 gene expression in the embryonic tissues are not well understood. Here we report that the hypoxia-inducible factor 1 (HIF-1) pathway is established in early embryogenesis and mediates hypoxia-induced IGFBP-1 expression. Hypoxia increased the HIF-1 activity, and HIF-1α overexpression or CoCl2 treatment resulted in elevated IGFBP-1 expression in zebra fish embryos. Although the zebra fish IGFBP-1 promoter contains 13 consensus hypoxia response elements (HREs), deletion and mutational analysis revealed that only the HRE positioned at −1090/−1086 is required for the hypoxia and HIF-1 induction. Further experiments revealed that there is an HIF-1 ancillary sequence (HAS) adjacent only to the functional HRE. Mutation of this HAS greatly reduced the responsiveness of the IGFBP-1 promoter to hypoxia and HIF-1. The HAS does not directly bind to HIF-1 or affect the binding of the HRE to HIF-1. The HAS is bound to a nuclear protein(s), and this HAS binding activity is reduced by hypoxia. These results suggest that HIF-1 mediates hypoxia-induced IGFBP-1 gene expression in early development by selectively interacting with the −1090/−1086 HRE and its adjacent HAS.


2021 ◽  
Vol 22 (12) ◽  
pp. 6267
Author(s):  
Meng-Jin Lin ◽  
Mei-Chun Lu ◽  
Hwan-You Chang

The goals of this study are to develop a high purity patented silk fibroin (SF) film and test its suitability to be used as a slow-release delivery for insulin-like growth factor-1 (IGF-1). The release rate of the SF film delivering IGF-1 followed zero-order kinetics as determined via the Ritger and Peppas equation. The release rate constant was identified as 0.11, 0.23, and 0.09% h−1 at 37 °C for SF films loaded with 0.65, 6.5, and 65 pmol IGF-1, respectively. More importantly, the IGF-1 activity was preserved for more than 30 days when complexed with the SF film. We show that the IGF-1-loaded SF films significantly accelerated wound healing in vitro (BALB/3T3) and in vivo (diabetic mice), compared with wounds treated with free IGF-1 and an IGF-1-loaded hydrocolloid dressing. This was evidenced by a six-fold increase in the granulation tissue area in the IGF-1-loaded SF film treatment group compared to that of the PBS control group. Western blotting analysis also demonstrated that IGF-1 receptor (IGF1R) phosphorylation in diabetic wounds increased more significantly in the IGF-1-loaded SF films group than in other experimental groups. Our results suggest that IGF-1 sustained release from SF films promotes wound healing through continuously activating the IGF1R pathway, leading to the enhancement of both wound re-epithelialization and granulation tissue formation in diabetic mice. Collectively, these data indicate that SF films have considerable potential to be used as a wound dressing material for long-term IGF-1 delivery for diabetic wound therapy.


1995 ◽  
Vol 269 (5) ◽  
pp. E977-E981 ◽  
Author(s):  
C. V. Jurasinski ◽  
T. C. Vary

Sepsis causes an inhibition of protein synthesis in gastrocnemius that is resistant to the anabolic effects of insulin. The purpose of the present studies was to investigate the effect of recombinant human insulin-like growth factor I (IGF-I) on protein synthesis during a 30-min perfusion of the isolated rat hindlimb from septic rats. Inclusion of IGF-I (1 or 10 nM) in the perfusate stimulated protein synthesis in gastrocnemius of septic rats 2.5-fold and restored rates of protein synthesis to those observed in control rats. The stimulation of protein synthesis did not result from an increase in the RNA content but was correlated with a 2.5-fold increase in the translational efficiency. The enhanced translational efficiency was accompanied by a 33 and 55% decrease in the abundance of free 40S and 60S ribosomal subunits, respectively, indicating that IGF-I accelerated peptide-chain initiation relative to elongation/termination. These studies provide evidence that IGF-I can accelerate protein synthesis in gastrocnemius during chronic sepsis by reversing the sepsis-induced inhibition of peptide-chain initiation.


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