The Study Of KCNJ5Mutations In Adrenal Aldosterone-Producing Adenomas And Adrenal Hyperplasia

Objective:Primary aldosteronism is a type of secondary hypertension. The aldosterone-producing adenoma(APA) and adrenal hyperplasia(AH) are two commonly types of primary aldosteronism. Some researchers have found mutation of KCNJ5gene that encodes G-protein coupled (gated) inward rectifier potassium channel4(G protein-coupled inwardly-rectifying potassium channels4) leads to KCNJ5channel abnormality which results in increased synthesis of aldosterone, and elevated blood pressure.More and more researches are focusing on the KCNJ5gene in order to clarify the pathogenesis of (APA) and (AH).This study intends to survey the relationship between the KCNJ5mutation and the molecular mechanism of pathogenesis of (APA) and (AH). Methods:(1)46cases of adrenal adenoma and14cases of adrenal hyperplasia tissues were collected from The Peoples Hospital of Xin jiang Uyghur autonomous region from2008to2011. Meanwhile the basic clinical data (age, ethnic group, gender, and plasma aldosterone and renin, serum potassium, urine potassium concentration)were collected; normal adrenal gland beside adenoma as control group.(2) Extraction the DNA from adrenal adenoma and adrenal hyperplasia tissues, and the exons1,2,3and the promoter region of KCNJ5gene was amplified by PCR and sequenced, using the analysis software to compare the sequenced maps to the NCBI database, expected to find the KCNJ5gene mutations.(3) According to the sequenced results,8mutation tissues,and9the wild type tissues were selected;7normal tissues surrounding the tumor as the control group; the ion channel gene expression selected according to signal pathway using PCR Arrary screening.Results:1Mutations was found in41.3%(19/46)of the APA, including missense mutation in19cases, synonymous mutation in4cases, G151R mutation in5cases (10.8%), L168R in4cases,(8.7%), S209T mutation in12cases (26.1%); synonymous mutations in13cases, of which2cases were L270,2cases H278,and nine S57.10SNPs loci were also found such as -20210G/C,5521T/A,rsll221498,rs11221497,rs45516097,rs72542772,rs4937391,rs3867256,rs4373934, rs2604204,of which-20210G/C and5521T/A were first reported.2Compared the clinical phenotypes difference of systolic blood pressure, diastolic blood pressure, serum potassium ion concentration, urine potassium ion concentration, sitting aldosterone levels, between KCNJ5G151R, L168R, S209T mutation groups and its wild type groups respectively. However, differences of systolic and diastolic blood pressure were statistically significant just in the G151R group and wild goup (P<0.05).3sequencing revealed57.1%a mutations (8/14) in adrenal hyperplasia tissues, including8missense mutations;G151R in2cases (14.2%), L168R in1cases (7.1%), S209T in5cases (35.7%). Nonsence mutations in4cases of which,2cases of L270,2cases of H278.5SNPs were also found, of which-5521T/A is first discovered.4Compared the clinical phenotypes difference of systolic blood pressure, diastolic blood pressure, serum potassium ion concentration, urine potassium ion concentration, sitting aldosterone levels, between KCNJ5G151R, L168R, S209T mutation groups and its wild type groups,respectively.The results showed the differences of those clinical phenotypes were not statistically significant.5Comparison between KCNJ5G151R,L168R mutation group and the control group revealed that29genes such as KCNJ6, KCNJ5, SCN1A2, SCN1A, CACNB1, and KCNH7,expression were up-regulated, and7genes such as SCN10A, and TRPV4down-regulated in the mutated group. Comparison between adrenal adenoma KCNJ5wild type and control group showed thatl3genes such as SCN10A, KCNJ5, KCNJ15, TRPV4, CACNB1, were up-regulated and7genes such as CACNA1B, KCNJ6, KCNJ1, TRPV1, KCNJ14, TRPV3were down-regulated. Conclusion:1This study was reported a new missense mutation S209T in adrenal adenoma firstly; meanwhile3missense mutations were also found in the adrenal hyperplasia. KCNJ5mutations ratio was41.3%in adrenal adenoma, G151R and L168R mutations ratio was19.6%,slightly lower than that of foreign literature.2The mutation occurrence in the adrenal hyperplasia was higher than that of APA patients.3PCR Array results showed that mutation of KCNJ5gene up-regulated in adrenal adenoma and wild type adenoma gene differentially; KCNJ5may regulate the expression of ion channel genes that associated with adrenal adenoma, and these genes may also be involved in adrenal adenoma occurrence.