Department of Pathology, National Hospital Organization Sendai medical center, Sendai, Japan; Department of Pathology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Japan.
Department of Pathology, Tohoku Graduate School of Medicine, Tohoku University, Sendai, Japan.
J Steroid Biochem Mol Biol. 2022 Jul;221:106116. doi: 10.1016/j.jsbmb.2022.106116. Epub 2022 May 6.
Aldosterone-producing adenoma (APA) is histologically composed of clear and compact tumor cells. KCNJ5- mutated APAs were reported to be associated with higher plasma aldosterone concentration and more abundant clear tumor cells containing lipid droplets than non-KCNJ5- mutated APAs. However, the association among cholesterol uptake and/or synthesis, cellular morphology and genotypes has remained unknown. Therefore, in order to explore these differences, 52 APA cases (KCNJ5 mt: n = 33, non-KCNJ5 mt: n = 19; ATP1A1: n = 3, ATP2B3: n = 3, CACNA1D: n = 5, CTNNB1: n = 1, tumors without any mutation above: n = 7), zona glomerulosa (ZG) tissue adjacent to APA and 10 non-pathological adrenal glands (NAs) were examined for quantitative histopathological analysis of tumor morphology and immunohistochemical analysis of cholesterol receptors (SR-B1, LDL-R), cholesterol metabolic enzymes (ACAT1, ACAT2, HSL, DHCR24, StAR), and the enzymes required for steroid synthesis (CYP11A1, CYP17A, 3βHSD, CYP11B1, CYP11B2). Gas chromatography-mass spectrometry (GC-MS) analysis was further performed to profile cholesterol precursors and metabolites in 21 APA cases (KCNJ5 mt: n = 16, non-KCNJ5 mt: n = 5) and 14 adrenal cortex of adjacent adrenal tissues. Results demonstrated that both SR-B1 and DHCR24 were significantly lower in the ZG than in fasciculata or reticularis of NAs but LDL-R was not significantly different among them in immunohistochemical analysis. SR-B1 and DHCR24 were both significantly higher in APAs than in ZG tissue adjacent to APA. In GC-MS analysis, most cholesterol precursors and metabolites, except for lanosterol, and their metabolic ratios (= concentration of cholesterol/ precursor) were higher in APAs than in the adjacent adrenal cortex tissue. LDL-R, ACAT1/2, HSL, DHCR24 were all significantly lower in clear than in compact tumor cells of APA. LDL-R was significantly lower and cholesterol/lanosterol ratio was significantly higher in KCNJ5- mutated than non-KCNJ5- mutated APAs. We demonstrated SR-B1 mediated selective uptake of cholesterol ester and de novo cholesterol synthesis were both enhanced in APAs. In addition, cholesterol uptake and metabolism were different between clear and compact tumor cells. KCNJ5- mutated APAs were predominantly composed of clear tumor cells containing abundant cholesteryl ester but less activated LDL-R mediated uptake and increased de novo synthesis. Those findings above indicated their more pronounced functional deviation from the normal ZG cells in terms of their steroidogenic and intracellular cholesterol metabolism.
醛固酮瘤（APA）在组织学上由透明和致密的肿瘤细胞组成。有报道称，KCNJ5 突变的 APA 与更高的血浆醛固酮浓度和更丰富的含有脂滴的透明肿瘤细胞有关，而非 KCNJ5 突变的 APA 则不然。然而，胆固醇摄取和/或合成、细胞形态和基因型之间的关联仍不清楚。因此，为了探讨这些差异，我们检查了 52 例 APA 病例（KCNJ5 mt：n=33，非-KCNJ5 mt：n=19；ATP1A1：n=3，ATP2B3：n=3，CACNA1D：n=5，CTNNB1：n=1，无上述任何突变的肿瘤：n=7）、APA 旁的球状带（ZG）组织和 10 例非病理性肾上腺（NA）组织，对肿瘤形态进行定量组织病理学分析，并对胆固醇受体（SR-B1、LDL-R）、胆固醇代谢酶（ACAT1、ACAT2、HSL、DHCR24、StAR）和类固醇合成所需的酶（CYP11A1、CYP17A、3βHSD、CYP11B1、CYP11B2）进行免疫组织化学分析。进一步通过气相色谱-质谱分析（GC-MS）对 21 例 APA 病例（KCNJ5 mt：n=16，非-KCNJ5 mt：n=5）和 14 例相邻肾上腺皮质组织中的胆固醇前体和代谢物进行了分析。结果表明，与 NA 的束状带或网状带相比，SR-B1 和 DHCR24 在 ZG 中的表达均显著降低，但 LDL-R 的免疫组化分析在三者之间无显著差异。与 APA 旁的 ZG 组织相比，SR-B1 和 DHCR24 在 APA 中均显著升高。GC-MS 分析表明，除了羊毛甾醇外，大多数胆固醇前体和代谢物及其代谢比值（=胆固醇/前体浓度）在 APA 中均高于相邻肾上腺皮质组织。LDL-R、ACAT1/2、HSL、DHCR24 在透明细胞肿瘤中均显著低于致密细胞肿瘤。在 KCNJ5 突变的 APA 中，LDL-R 显著降低，胆固醇/羊毛甾醇比值显著升高。我们证明了 SR-B1 介导的胆固醇酯选择性摄取和从头胆固醇合成均在 APA 中增强。此外，胆固醇摄取和代谢在透明细胞和致密细胞肿瘤之间存在差异。KCNJ5 突变的 APA 主要由富含胆固醇酯但 LDL-R 介导的摄取活性降低和从头合成增加的透明肿瘤细胞组成。上述发现表明，与正常 ZG 细胞相比，它们在类固醇生成和细胞内胆固醇代谢方面的功能偏差更为明显。
