The Primary Aldosteronism Kcnj5 Gene Mutations And Protein Expression Studies,

ObjectivesPrimary aldosteronism (PA) is a group of disorders in which aldosterone production is inappropriately high, relatively autonomous from the renin-angiotensin system, and nonsuppressible by sodium loading. Mutation of the KCNJ5gene (encodes a potassium channel) have recently been identified in patients with sporadic aldosterone-producing adenomas (APA). The aim of this study was to investigate the prevalence of KCNJ5mutations in unselected Chinese patients with primary aldosteronism and their clinical, biological and molecular correlates.Methods1. Sequencing KCNJ5gene from DNA and cDNA in tumors and DNA in bloods of48patients with APA and9patients with adrenal nodular hyperplasia coming from Peking Union Medical Hospital.2. Sequencing KCNJ5gene form DNA in bloods of10patients with IHA and4familial PA families coming from Peking Union Medical Hospital.Results1. Of the48patients with APA,25(54.2%) patients had two types' somatic mutations of the KCNJ5gene:12tumors are p. G151R,13tumors are p. L168R;1patient has p.157delI mutation which was reported;1patient has p.148dupT mutation unreported.2. Of the9patients with nodular hyperplasia,5(55.6%) had two type somatic mutations of the KCNJ5gene:2cases are p. G151R,3cases are p. L168R.3. In48APA patients, mutation group has lower BMI (P<0.01), longer hypopotassium duration (P<0.01), lower serum potassium (P<0.01), higher plasma aldostrone (P<0.05), lower captopril inhibite aldosterone rate (P<0.05), higher blood pressure after surgery (P<0.05); while no gender, hypertension duration, response to angiotensin Ⅱ, tumor diameter difference exist between mutation group and non-mutation group. 4. In48APA patients, p. L168R mutation group seems younger than non-mutation group (P<0.05); p. G151R mutation group have higher aldosterone level than non-mutation group (P<0.05); the two mutation groups are inclined to have relatively lower BMI, higher blood pressure and lower serum potassium (P<0.01). No difference of p. G151R and p. L168R in clinical characteristics. No difference of tumors'diameters among these groups.5. In9NH patients, no clinical difference between mutation group and non-mutation group; NH mutation group and higher captopril inhibite aldosterone rate than APA mutation group.6. The SNP genotypes of48patients with APA have no statistic significance with SNP database of PUMCH.Conclusion1. In sporadic APA patients of PUMCH, KCNJ5gene somatic mutation rate is56.3%, higher than European and Australian(34～44%), while closer to Japanese(65.2%); which indicated that KCNJ5gene mutation rate has race difference.2. Somatic p.G151R and p. L168R mutations exist in adrenal nodular hyperplasia PA patients.3. Somatic KCNJ5gene mutation not exists in CPA and PCC patients.4. Four KCNJ5mutation types exist in our study group, p. L168R,p. G151R, p. del157I and p.148dupT, p.148dupT is a new mutation type associated with APA.5. KCNJ5gene mutation type associated with sporadic APA patients' clinical condition. ObjectivesThe purpose of this study is to detect the protein level of KCNJ5in human different adrenocortical diseases, including Primary aldosteronism, Cortisol-producing adenoma, Pheochromocytoma and Normal adrenal cortex, to investigate the condition of KCNJ5protein in Primary aldosteronism。MethodsTotal protein was extracted and evaluated from8normal human adrenal cortex,43primary aldosteronism include38adrenal aldoterone-producing adenomas(APA) and5nodular hyperaldosteronism(NH),7cortisol-producing adenomas(CPA),6pheochromocytomas(PCC).We analyzed the protein expression of KCNJ5and GAPDH using Western blot. The protein expression of KCNJ5was semi-quantified by dividing the grayness value of KCNJ5/GAPDH in the same sample.The level of KCNJ5protein was compared between KCNJ5mutation APA and KCNJ5non-mutation APA, and analyses with patients'clinical data.Results1. KCNJ5protein expression in normal adrenal cortex was higher than aldosterone-producing adenoma, nodular hyprealdosteronism (p<0.01); KCNJ5protein expression in KCNJ5non-mutation APA was higher than KCNJ5mutation APA (P<0.05), and nodular hyprealdosteronism (P<0.05), and cortisol producing adenoma (P<0.05), and pheochromocytoma (P<0.05); no KCNJ5protein expression difference between KCNJ5gene p.G151R mutation type and p. L168R mutation type;2. KCNJ5protein expression was positive correlated with KCNJ5mutation condition, r=0.516,P=0.005;3. KCNJ5protein expression was not correlated with clinical data of KCNJ5mutated patients and KCNJ5non-mutated patients. Concliusion1.KCNJ5protein expression level is lower than normal adrenal cortex, KCNJ5mutation APA and NH were significant lower, which indicated that KCNJ5protein was down regulated because KCNJ5gene mutation;2. KCNJ5protein expression is not correlated with clinical condition of APA patients;3. KCNJ5protein expression level in Cortical producing adenoma and Pheochromocytoma tumor tissue is lower than normal adrenal cortex, its meaning should be studied further.