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5976070 
Journal Article 
Increased renal gene transcription of protein kinase C- (Sb (Bin human diabetic nephropathy: relationship to long-term glycaemic control 
Christensen, PK; Cox, AJ; Gilbert, RE; Gow, RM; Kelly, DJ; Langham, RG; Parving, HH; Pollock, CA; Qi, W; Thai, K; Zhang, Y 
2008 
Yes 
Diabetologia
ISSN: 0012-186X
EISSN: 1432-0428 
Berlin/Heidelberg : Springer-Verlag 
Diabetologia 
51, no. 4 
668-674 
Aims/hypothesis Activation of protein kinase C (PKC) isoforms has been implicated as a central mediator in the pathogenesis of diabetic nephropathy. Although high glucose levels stimulate catalytic activity of PKC, the effects of high glucose levels on the expression of genes encoding PKC isoforms are unknown. We sought to determine whether in addition to activation, diabetes may lead to increased transcription of two PKC isoforms that have been implicated in the pathogenesis of diabetic nephropathy, PKC- (Sa (Band PKC- (Sb (B. Methods Recent advances in molecular biological techniques now permit quantitative analysis of mRNA from archival, formalin-fixed, paraffin-embedded tissue sections. RNA was extracted from scraped 6 (So (Bm sections of biopsy tissue, and PRKC- (Sa (Band PRKC- (Sb (B(also known as PRKCA and PRKCB) mRNA measured using real-time PCR. Expression of genes encoding PKC isoforms was examined in renal biopsies (n = 25) with classical histological features of diabetic nephropathy and compared with that in normal control tissue (n = 6). Peptide localisation of PKC- (Sa (B, PKC- (Sb (Band the activated forms phosphorylated PKC- (Sa (Band - (Sb (Bwas also performed on matched paraffin-embedded sections of renal biopsies using immunohistochemistry. The effects of high glucose on PRKC- (Sb (Bexpression and peptide production in cultured human proximal tubular epithelial cells were assessed. Results Quantitative real-time PCR demonstrated a 9.9-fold increase in PRKC- (Sb (BmRNA in kidney biopsies of diabetic patients relative to control (p < 0.001). No increase in PRKC- (Sa (Bexpression was seen. In addition, a correlation between renal PRKC- (Sb (BmRNA and HbA b1 sc was observed in diabetic patients (r = 0.63, p < 0.05). There was co-localisation of PKC- (Sb (Band phospho-PKC- (Sb (Bpredominantly to proximal tubules. A 60% increase in PRKC- (Sb (BmRNA and peptide in cultured human proximal tubular epithelial cells exposed to high glucose (p < 0.05) was seen in vitro. Conclusions/interpretation PKC- (Sb (Bis upregulated at the gene expression level in human diabetic nephropathy. PRKC- (Sb (BmRNA correlates closely with serum HbA b1 sc, possibly partially explaining the relationship between glycaemic control and progression of diabetic nephropathy. Archival human tissue provides a valuable resource for molecular analyses. 
diabetic nephropathy; protein kinase C; Human renal biopsies; Hyperglycaemia; PKC- (Sa (B; PKC- (Sb (B; Internet resource