Figures
- Figure 1–
Current model of the mechanisms controlling glucose concentrations in the surface liquid lining the airway and distal lung epithelium. a) In the airway epithelium, the glucose concentration of the airway surface liquid (ASL) is the net effect of paracellular diffusion (and, to a lesser extent, the transcellular flux of glucose) from the blood and interstitial fluid across respiratory epithelium into the ASL, and removal of glucose from ASL by uptake into epithelial cells. Glucose uptake across the apical membrane is mediated by facultative glucose transporter (GLUT)2 and GLUT10, and across the basolateral membrane by GLUT2 and GLUT1. b) In the distal (alveolar) lung epithelium, glucose uptake across the apical membrane is via sodium-coupled glucose transporter (SGLT)1 and the basolateral membrane via unidentified GLUTs.
Tables
- Table 1– Facultative glucose transporter (GLUT) and sodium-coupled glucose transporter (SGLT) expression in human cultured epithelial cells, human bronchial tissue and whole lung
Transporter Human cultured epithelial cells Bronchial tissue Whole lung H441 HBECs Nonpolarised Polarised mRNA Protein mRNA Protein mRNA Protein mRNA Protein mRNA Protein GLUTs GLUT1 + [13] - [13] - [13] + [11] + [11] + [11] - [45] + [47] - [45, 46] GLUT2 + [13] + [13] + [10, 13] + [11] - [11] + [11] + [13, 46] GLUT3 - [13] - [13] - [13] + [11] - [11] + [11] - [45] + [47] - [45, 46] GLUT4 + [13] + [13] - [13] + [11] - [11] + [11] - [45] - [45, 46] GLUT5 + [11] + [11] - [45] + [47] - [45, 46] GLUT6 + [11] + [11] GLUT7 + [11] + [11] GLUT8 + [11] - [11] + [11] GLUT9 + [11] + [11] GLUT10 + [10] + [11] + [11] + [11] + [48] GLUT11 + [11] + [11] GLUT12 + [11] + [11] SGLTs SGLT1 + [11] - [11] + [11] + [49] SGLT2 + [11] - [11] + [11] + [49] HBEC: human bronchial epithelial cells; +: present; -: absent.
- Table 2– Facultative glucose transporter (GLUT) and sodium-coupled glucose transporter (SGLT) expression in whole lung, and bronchial and alveolar# epithelium in fetal and adult stages
Transporter Whole lung Bronchial epithelium Alveolar epithelium Fetal Adult Fetal Adult Fetal Adult RNA Protein RNA Protein RNA Protein RNA Protein RNA Protein RNA Protein GLUTs GLUT1 + [50, 51] + [50] + [51, 52] + [57]
- [58]§- [58]§ + [59]
- [58]§+ [60] - [58]§ GLUT2 + [53]¶ + [45] - [60] GLUT3 GLUT4 + [52] + [60] GLUT5 + [60] GLUT6 GLUT7 GLUT8 GLUT9 GLUT10 GLUT12 + [57] SGLTs SGLT1 + [54, 55] + [56]§ - [45]ƒ + [60] + [61]
+ [61]##SGLT2 - [60] Expression in rats unless otherwise stated. +: present; -: absent. #: type II cells; ¶: pig; §: mouse; ƒ: rabbit; ##: sheep.
