Human iPS cell-derived mural cells as an in vitro model of hereditary cerebral small vessel disease.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is one of the most common forms of hereditary cerebral small vessel diseases and is caused by mutations in NOTCH3. Our group has previously reported incorporation of NOTCH3 extracellular domain (N3ECD) in the CADASIL-specific granular osmiophilic materials and increase of PDGFRß immunoreactivity in CADASIL postmortem brains. Here, we aimed to establish an in vitro model of CADASIL, which can recapitulate those CADASIL phenotypes, using induced pluripotent stem cells (iPSCs). We have refined a differentiation protocol of endothelial cells to obtain mature mural cells (MCs) with their characteristic properties. iPSCs from three CADASIL patients with p.Arg182Cys, p.Arg141Cys and p.Cys106Arg mutations were differentiated into MCs and their functional and molecular profiles were compared. The differentiated CADASIL MCs recapitulated pathogenic changes reported previously: increased PDGFRß and abnormal structure/distribution of filamentous actin network, as well as N3ECD/LTBP-1/HtrA1-immunopositive deposits. Migration rate of CADASIL MCs was enhanced but suppressed by knockdown of NOTCH3 or PDGFRB. CADASIL MCs showed altered reactivity to PDGF-BB. Patient-derived MCs can recapitulate CADASIL pathology and are therefore useful in understanding the pathogenesis and developing potential treatment strategies.

Evaluation of quantitative parameters for distinguishing pheochromocytoma from other adrenal tumors.

Adrenal tumors are increasingly found incidentally during imaging examinations. It is important to distinguish pheochromocytomas from other adrenal tumors because of the risk of hypertensive crisis. Although catecholamines and their metabolites are generally used to diagnose pheochromocytoma, false-positive test results are common. An effective screening method to distinguish pheochromocytoma from adrenal incidentalomas is needed. We analyzed 297 consecutive patients with adrenal incidentalomas. Our findings included 162 non-functioning tumors, 47 aldosterone-producing adenomas, 26 metastases, 22 cases of subclinical Cushing's syndrome, 21 pheochromocytomas, 12 cases of Cushing's syndrome, and 7 adrenocortical cancers. We checked quantitative parameters such as age, blood, and urine catecholamines and their metabolites, neuron-specific enolase, size and computed tomography (CT) attenuation values. Among catecholamine-related parameters, the sum of urine metanephrine and normetanephrine (urineMNM) levels produced the highest area under the receiver operating characteristic curve regarding discrimination of pheochromocytoma from other lesions. Size and CT attenuation values also differed significantly. However, size was correlated with catecholamine levels. CT attenuation was not correlated with other factors. The optimal thresholds were 19 Hounsfield units (HU) for CT attenuation (sensitivity, 100%; specificity, 60%) and 0.43 mg/24 h for urineMNM (sensitivity, 89%; specificity, 96%). No pheochromocytomas were evident when CT attenuation values were under 19 HU. Even in adrenal tumors with CT attenuation values ≥ 19 HU, when urineMNM was < 0.43 mg/24 h, the frequency of pheochromocytoma was only 4.3%, when urineMNM was ≥ 0.43 mg/24 h, the frequency of pheochromocytoma was 93% and when urineMNM was > 0.77 mg/24 h the frequency of pheochromocytoma was 100%. CT attenuation value and urineMNM represented the most useful combination for diagnosis of pheochromocytoma.

Significance of dopamine D1 receptor signalling for steroidogenic differentiation of human induced pluripotent stem cells.

Human induced pluripotent stem cells (hiPSCs) are expected to be both a revolutionary cell source for regenerative medicine and a powerful tool to investigate the molecular mechanisms underlying human cell development in vitro. In the present study, we tried to elucidate the steroidogenic differentiation processes using hiPSC-derived intermediate mesoderm (IM) that is known to be the origin of the human adrenal cortex and gonads. We first performed chemical screening to identify small molecules that induce steroidogenic differentiation of IM cells expressing Odd-skipped related 1 (OSR1), an early IM marker. We identified cabergoline as an inducer of 3ß-hydroxysteroid dehydrogenase, an essential enzyme for adrenogonadal steroidogenesis. Although cabergoline is a potent dopamine D2 receptor agonist, additional experiments showed that cabergoline exerted effects as a low-affinity agonist of D1 receptors by increasing intracellular cyclic AMP. Further analysis of OSR1+ cells transfected with steroidogenic factor-1/adrenal 4 binding protein revealed that D1 receptor agonist upregulated expression of various steroidogenic enzymes and increased secretion of steroid hormones synergistically with adrenocorticotropic hormone. These results suggest the importance of dopamine D1 receptor signalling in steroidogenic differentiation, which contributes to effective induction of steroidogenic cells from hiPSCs.

Crucial Role of Mesangial Cell-derived Connective Tissue Growth Factor in a Mouse Model of Anti-Glomerular Basement Membrane Glomerulonephritis.

Connective tissue growth factor (CTGF) coordinates the signaling of growth factors and promotes fibrosis. Neonatal death of systemic CTGF knockout (KO) mice has hampered analysis of CTGF in adult renal diseases. We established 3 types of CTGF conditional KO (cKO) mice to investigate a role and source of CTGF in anti-glomerular basement membrane (GBM) glomerulonephritis. Tamoxifen-inducible systemic CTGF (Rosa-CTGF) cKO mice exhibited reduced proteinuria with ameliorated crescent formation and mesangial expansion in anti-GBM nephritis after induction. Although CTGF is expressed by podocytes at basal levels, podocyte-specific CTGF (pod-CTGF) cKO mice showed no improvement in renal injury. In contrast, PDGFRα promoter-driven CTGF (Pdgfra-CTGF) cKO mice, which predominantly lack CTGF expression by mesangial cells, exhibited reduced proteinuria with ameliorated histological changes. Glomerular macrophage accumulation, expression of Adgre1 and Ccl2, and ratio of M1/M2 macrophages were all reduced both in Rosa-CTGF cKO and Pdgfra-CTGF cKO mice, but not in pod-CTGF cKO mice. TGF-ß1-stimulated Ccl2 upregulation in mesangial cells and macrophage adhesion to activated mesangial cells were decreased by reduction of CTGF. These results reveal a novel mechanism of macrophage migration into glomeruli with nephritis mediated by CTGF derived from mesangial cells, implicating the therapeutic potential of CTGF inhibition in glomerulonephritis.

Role of endogenous ACTH on circadian aldosterone rhythm in patients with primary aldosteronism.

We recently reported that stimulation with high-dose ACTH caused different responses in terms of aldosterone secretion in aldosterone-producing adenomas (APAs) and idiopathic hyperaldosteronism (IHA) in patients with primary aldosteronism (PA). However, the role of endogenous ACTH in aldosterone secretion in PA has not been systematically evaluated. In this study, we examined diurnal changes in plasma aldosterone concentration (PAC), and changes in PAC after dexamethasone administration in patients with suspected PA, in order to evaluate the effect of endogenous ACTH on aldosterone secretion. Seventy-three patients admitted to Kyoto University Hospital with suspected PA were included. The patients were classified into non-PA, IHA, and APA groups according to the results of captopril challenge test and adrenal venous sampling. PAC at 0900 h (PAC0900), 2300 h (PAC2300), and after 1-mg dexamethasone suppression test (PACdex) was measured and compared among the three groups. The PAC2300/PAC0900 and PACdex/PAC0900 ratios were also analyzed. PAC2300 and PACdex were lower than PAC0900 in all three groups. There were no significant differences in PAC2300/PAC0900 among the three groups. However, PACdex/PAC0900 was significantly lower in the APA group compared with the non-PA and IHA groups. The results of this study indicate that aldosterone secretion in APA patients is more strongly dependent on endogenous ACTH than in IHA and non-PA patients. The results also suggest that factors other than ACTH, such as clock genes, may cause diurnal changes in aldosterone secretion in IHA and non-PA patients.

Adrenal reserve function after unilateral adrenalectomy in patients with primary aldosteronism.

OBJECTIVE: After unilateral adrenalectomy (uADX) in patients with a unilateral aldosterone-producing adenoma (APA), the remaining contralateral adrenal gland is generally considered sufficient to support life. However, few studies have compared adrenal reserve function before and after uADX. Therefore, we closely evaluated adrenal cortisol secretory function before and after uADX in patients with unilateral APA. METHODS: Patients who were diagnosed with APA and underwent uADX for unilateral APA were initially included in this study. Patients with subclinical Cushing's syndrome (SCS) or Cushing's syndrome were excluded on suspicion of autonomous cortisol secretion. Fourteen patients were finally evaluated. Morning basal serum cortisol and plasma adrenocorticotropin hormone (ACTH) levels were measured, and ACTH stimulation tests under 1-mg dexamethasone suppression (dex-ACTH test) were performed before and after uADX. RESULTS: No patient developed clinical adrenal insufficiency. Basal cortisol levels were not significantly different before and after uADX. However, basal ACTH levels were significantly elevated after uADX. In addition, peak cortisol levels on the dex-ACTH test decreased in all patients after uADX. The peak cortisol level after uADX was 86.6 (81.4-92.4)% of the level before uADX. CONCLUSION: The adrenal cortisol secretory response to ACTH stimulation is mildly reduced after uADX in patients with unilateral APA without SCS or Cushing's syndrome, although their basal cortisol level is sustained by elevated ACTH. These data will be important as a point of discussion when patients with unilateral APA consider either uADX or specific pharmacotherapy as treatment options.

Differentiation of human embryonic stem cells and human induced pluripotent stem cells into steroid-producing cells.

Although there have been reports of the differentiation of mesenchymal stem cells and mouse embryonic stem (ES) cells into steroid-producing cells, the differentiation of human ES/induced pluripotent stem (iPS) cells into steroid-producing cells has not been reported. The purpose of our present study was to establish a method for inducing differentiation of human ES/iPS cells into steroid-producing cells. The first approach we tried was embryoid body formation and further culture on adherent plates. The resultant differentiated cells expressed mRNA encoding the steroidogenic enzymes steroidogenic acute regulatory protein, 3ß-hydroxysteroid dehydrogenase, cytochrome P450-containing enzyme (CYP)-11A1, CYP17A1, and CYP19, and secreted progesterone was detected in the cell medium. However, expression of human chorionic gonadotropin was also detected, suggesting the differentiated cells were trophoblast like. We next tried a multistep approach. As a first step, human ES/iPS cells were induced to differentiate into the mesodermal lineage. After 7 d of differentiation induced by 6-bromoindirubin-3'-oxime (a glycogen synthase kinase-3ß inhibitor), the human ES/iPS cells had differentiated into fetal liver kinase-1- and platelet derived growth factor receptor-α-expressing mesodermal lineage cells. As a second step, plasmid DNA encoding steroidogenic factor-1, a master regulator of steroidogenesis, was introduced into these mesodermal cells. The forced expression of steroidogenic factor-1 and subsequent addition of 8-bromoadenosine 3',5'-cyclic monophosphate induced the mesodermal cells to differentiate into the steroidogenic cell lineage, and expression of CYP21A2 and CYP11B1, in addition to steroidogenic acute regulatory protein, 3ß-hydroxysteroid dehydrogenase, CYP11A1, and CYP17A1, was detected. Moreover, secreted cortisol was detected in the medium, but human chorionic gonadotropin was not. These findings indicate that the steroid-producing cells obtained through the described multistep method are not trophoblast like; instead, they exhibit characteristics of adrenal cortical cells.

A case of myelolipoma with bilateral adrenal hyperaldosteronism cured after unilateral adrenalectomy.

Myelolipomas are adrenal tumors composed of both adipose and hematopoietic tissues which are rarely associated with primary aldosteronism (PA). Here, we report a case of myelolipoma associated with PA. Aldosterone hypersecretion from bilateral adrenal glands had been confirmed by adrenal venous sampling and pathological analyses, but PA was clinically cured after surgical removal of the unilateral adrenal gland together with the myelolipoma that was not producing aldosterone. It is suggested that myelolipomas may release some factors which stimulate aldosterone production in adrenal glands, although further investigation is necessary. Obesity-related hyperaldosteronism might in part participate in generation of hypertension in the present case.

Significance of adrenocorticotropin stimulation test in the diagnosis of an aldosterone-producing adenoma.

CONTEXT: Adrenal venous sampling is the "gold standard" test in the diagnosis of an aldosterone-producing adenoma (APA) among patients with primary aldosteronism (PA) but is available only in specialized medical centers. Meanwhile, an APA is reported to be generally more sensitive to ACTH than idiopathic hyperaldosteronism. OBJECTIVE: The aim was to evaluate the diagnostic accuracy of the ACTH stimulation test in the diagnosis of an APA among those with suspicion of PA. PATIENTS AND SETTING: Fifty-nine patients admitted to Kyoto University Hospital on suspicion of PA were included in the study. INTERVENTIONS: ACTH stimulation tests with 1-mg dexamethasone suppression were performed. MAIN OUTCOME MEASURE: Plasma aldosterone concentrations (PAC) were examined every 30 min after ACTH stimulation. Receiver-operated characteristics curve analysis was used to evaluate the diagnostic accuracy. RESULTS: PAC after ACTH stimulations were significantly higher in patients with an APA than in patients with idiopathic hyperaldosteronism or non-PA. Receiver-operated characteristics curve analyses showed that the PAC after ACTH stimulation was effective for the diagnosis of an APA among patients suspected of PA. The diagnostic accuracy was highest at 90 min after ACTH injection, with the optimal cutoff value greater than 37.9 ng/dl corresponding with sensitivity and specificity of 91.3 and 80.6% for the diagnosis of an APA. CONCLUSIONS: Our study indicates that the ACTH stimulation test is useful in the diagnosis of an APA among patients suspected of PA. This test can be used to select patients who are highly suspected of an APA and definitely require adrenal venous sampling.