ACE gene polymorphism in children with nephrotic syndrome in the Indonesian population.

BACKGROUND: The angiotensin converting enzyme (ACE) gene carries insertion (I) and deletion (D) polymorphism within its intron 16. The presence of D-allele in the ACE gene has been reported as a probable genetic risk factor for idiopathic nephrotic syndrome (INS), especially the subtype of focal segmental glomerulosclerosis (FSGS). The D-allele may be related to poor responsiveness to steroid therapy. To clarify the relationship between the D-allele and INS, we studied the prevalence of the D-allele in the Javanese-Indonesian patients. Additionally, we also analyzed relationship between each genotype and steroid sensitivity among the MCNS patients. METHODS: Eighty-five Javanese-Indonesian patients under 15 years of age with INS were enrolled in this study: 16 patients with FSGS and 69 patients with minimal change nephrotic syndrome (MCNS). As controls, 68 healthy adult Javanese-Indonesians with no history of kidney disease volunteered to participate in this study. Genotypes based on the polymorphisms (I/D) were determined by using a PCR method. As for the steroid responsiveness, the information of 14 out of 16 FSGS patient (87.5%) and 69 out of 69 MCNS patients (100%) was available. RESULTS: The genotype frequencies in the FSGS patients were II 37% (6/16), ID 44% (7/16) and DD 19% (3/16), and the D-allele frequency was 41% (13/32). The genotype frequencies in the MCNS patients were II 56% (39/69), ID 38% (26/69) and DD 6% (4/69), and the D-allele frequency was 25% (34/138). The genotype frequencies in the controls were II 60% (41/68), ID 31% (21/68), and DD 9% (6/68), and the D-allele frequency was 26% (33/136). None of the FSGS patients were sensitive to steroid, while almost all MCNS patients (66/69) were sensitive to steroid. The genotype frequencies among steroid-sensitive MCNS patients were consistent with those of the controls, suggesting that there was no relationship between each genotype and steroid sensitivity. CONCLUSIONS: In the Javanese-Indonesian population, none of the comparisons showed any significant differences in the genotypic distribution and allelic frequencies among the three groups, FSGS, MCNS and controls, although D-allele tended to exist more frequently in FSGS patients than in the MCNS patients and controls. In addition, the D-allele frequency was not related to steroid sensitivity in the MCNS patients.

Protein kinase C alpha associates with phospholipase D1 and enhances basal phospholipase D activity in a protein phosphorylation-independent manner in human melanoma cells.

It is well known that phospholipase D plays a crucial part in the signal transduction of many types of cells, and is activated by protein kinase C alpha when cells are stimulated. To elucidate the role of phospholipase D in melanoma, the expression of phospholipase D1 and protein kinase C alpha in primary and metastatic lesions of acral lentiginous melanoma and superficial spreading melanoma was investigated using immunohistologic techniques. In addition, the mechanism of regulation of phospholipase D1 by protein kinase C alpha was examined in a human melanoma cell line HM3KO using an adenovirus-mediated gene transfer technique. Both phospholipase D1 and protein kinase C alpha were strongly expressed in primary and metastatic lesions of superficial spreading melanoma. Conversely, in acral lentiginous melanoma lesions, the expression of these two proteins increased dramatically with tumor progression; the expression of both phospholipase D1 and protein kinase C alpha was almost negative in the radial growth phase of primary acral lentiginous melanoma lesions, and increased synchronously in a progression-related manner in advanced acral lentiginous melanoma lesions, including vertical growth phase and metastatic lesions. Immunoprecipitation study showed that phospholipase D1 and protein kinase C alpha are associated physiologically in resting melanoma cells. Further immunoprecipitation study using HM3KO cells after adenovirus-mediated simultaneous overexpression of phospholipase D1 and protein kinase C alpha, or phospholipase D1 and the kinase-negative mutant of protein kinase C alpha revealed that both protein kinase C alpha and the kinase-negative mutant of protein kinase C alpha are associated with phospholipase D1 in melanoma cells in the absence of an external signal. Overexpression of protein kinase C alpha or the kinase-negative mutant of protein kinase C alpha in melanoma cells by the adenovirus vectors resulted in the enhancement of basal phospholipase D activity in a viral concentration-dependent manner. Furthermore, enhanced basal phospholipase D activity increased the in vitro invasive potential of HM3KO cells. These results suggest that upregulation of phospholipase D1 and protein kinase C alpha plays a part in the progression of acral lentiginous melanoma from the radial growth phase to the vertical growth phase. The present results also suggest that protein kinase C alpha associates with phospholipase D1 and enhances basal phospholipase D activity in a protein phosphorylation-independent manner in melanoma cells, which contributes to the cell's high invasive potential.