Table 1.

Summary of recently published studies on impacts of HG or diabetes-induced changes on GJIC and hemichannels

Connexin	Cell/Tissue	Results	References
Cx43	T cells in non-obese diabetic (NOD) mice	Age-dependent loss of suppressor functions in T(regs) cells of NOD mice is associated with reduced GJIC and Cx43.	(Kuczma et al., 2015)
Cx43	Pericytes and endothelial cell (EC)	Diabetic pericytes are unable to sustain EC growth arrest in coculture and reduces Cx43.	(Durham et al., 2015)
Cx43	Rat retinal endothelial cells (RRECs)	HG downregulates Cx43 and GJIC, and downregulated Cx43 reduces tight junction protein ZO-1; Cx43 and GJIC may be involved in breakdown endothelial barrier in DR.	(Tien et al., 2013)
Cx30.2	Rat retinal endothelial cells (RRECs)	HG reduces Cx30.2 protein and diminishes GJIC; Cx30.2 knockout increases acelluar capillaries and pericyte loss, suggesting downregulation of Cx30.2 and GJIC in retinal vascular lesions in early DR.	(Manasson et al., 2013)
Cx43	Primary human dermal fibroblasts	Cx43 mimetic peptide Gap27 enhances scrape-wound closure in diabetic conditions by inhibiting GJIC; irrespective of the IGF-1:IGFBP-5 balance.	(Wright et al., 2013)
Cx43	Rat retinal endothelial cells (RRECs)	HG downregulates Cx43 in mitochondria; inhibition of gap junctions by β-GA induces mitochondrial fragmentation and increase cytochrome c release.	(Trudeau et al., 2012)
Cx43	Fibroblasts from the human chronic diabetic foot ulcers (DFU) and NIH3T3 cells	HG increases Cx43 protein and GJIC, and represses filopodial extensions and migration rates; upregulation of Cx43 in fibroblasts in DFUs correlates with inhibition of fibroblast migration.	(Mendoza-Naranjo et al., 2012)
Cx43	Human kidney (HK) 2 and human proximal tubule cells	TGF-β1 induced EMT leads to loss of E-cadherin, and reduces Cx43 and GJIC in the proximal tubules under diabetic conditions.	(Hills et al., 2012)
Cx37, Cx40 and Cx43	Human omental arteries and veins	In both vessels, responses to bradykinin are partially blocked by gap junction inhibitor carbenoxolone. GJIC is involved in endothelium-dependent hyperpolarizing (EDH) in response to bradykinin.	(Hammond et al., 2011)
Cx26, Cx30 and Cx43	Astrocytes and brain tissues	Reduced Cx30 and Cx43, not Cx26 are seen in cultured astrocytes by HG and in inferior colliculus of STZ-diabetic rats, not in cerebral cortex, and decreased GJIC in astrocytes by HG.	(Ball et al., 2011)
Not specified	Rabbit optic never head (ONH)	ONH blood flow is decreased in diabetic, not healthy rabbits, with reduced ocular perfusion pressure (OPP); inhibition of GJIC by octanol or Gap27 reduces ONH blood flow even in the healthy rabbits.	(Shibata et al., 2011)
Cx43	Ex vivo human skin tissue	Diabetic cells are less susceptible to Gap27 in cell migration and proliferation in early passages, and similar response in late passages and correlates with connexin hemichannel activity.	(Pollok et al., 2011)