A Novel Study of Protein Kinase C Beta Gene Polymorphism (rs3760106) and Protein Kinase C Activity Levels as a Predictor of Nephropathy Complications in Iraqi Diabetic Patients

Abstract

Objective: This study aimed to investigate the relation between the risk of (PRKCB-1504 C/T) gene polymorphisms and diabetic nephropathy pathogenesis and its association with its levels and some other biomarkers in serum of Iraqi diabetic nephropathy patients.
 Methods: A cross-sectional study was performed on 130 samples obtained from Al-Hussein Teaching Hospital / Kerbala – Iraq during Feb., 2020 to March. 2021. Seventy three patients of them with type 2 diabetes mellitus (T2D) and the remaining patients with type 2 diabetes mellitus with nephropathy complications (DN). Phenotypic analysis included determination of protein kinase C (PKC) activity levels, HbA1c%, serum insulin levels and renal function tests. Five ml of whole blood was obtained from each patients, 4.0 ml was centrifuged for serum separation used for biomarkers determinations and the remaining 1.0 ml was used for genomic DNA extraction for molecular analysis and polymorphism of PRKCB (rs3760106) by allele specific-amplification refractory mutational system-polymerase chain reaction (allele specific ARMS-PCR), followed by electrophoresis on 1% agarose gel. Various statistical analyses were applied to analyze the obtained data.
 Results: The amplification of the PRKCB gene gives one genotypes as indicated by (200 bp) bands for those with homozygous wild type (CC), homozygous mutant (TT) genotypes and two genotypes bands (200 bp) for those with heterozygous (CT). Genotype frequencies of rs3760106 polymorphism were found to be consistent with Hardy–Weinberg equilibrium. Allele frequencies (23.3 %, 26.7 %, 50 %) of CC, CT, TT in cases of DN group. While the frequencies in the non-DN group were (30 %, 45%, 25%) and for healthy control group were (50%, 33.4%, 16.6%) for wild, heterozygous, and homozygous in an order. In healthy control group, the risk of diabetic nephropathy was significantly higher among carriers of T allele under codominant TT (OR=6.42, 95%CI=(1.66-24.85), P=0.007), dominant CT+TT (OR=3.2, 95%CI = (1.08-9.95),P=0.03) and recessive model (OR=5, 95%CI = (1.51-16.56), P=0.008) while in T2DM without nephropathy the risk of diabetic nephropathy was significantly higher among carrier of T allele under recessive model (0R=3, 95%CI = (1.09-28.25), P= 0.003). Serum level of PKC-B1 activity was significantly higher among DN group than T2DM and control groups (43.35 ± 18.69, 30.35 ± 11.96, 27.42 ± 10.31, P=0.001), also PKC-B1 activity in DN group was significantly correlated with fasting blood glucose, HOMA-IR and renal function tests such as GFR, urea and creatinine.
 Conclusion: This study indicates that the PRKCB (C/T-1504) rs3760106 single nucleotide polymorphism was significantly associated with increased diabetic nephropathy susceptibility of Iraqi patients with T2DM and serum level of PKCB activity was associated with increase the risk of diabetic nephropathy complications.