Yoshimichi Takeda

The CYP11B2 gene is sporadically expressed in the zona glomerulosa (ZG), whereas the CYP11B1 gene is detected in the zona fasciculata (ZF)/reticularis (ZR), with predominant expression in the ZF. We studied the association between DNA methylation and adrenal zonation. Next, the CYP11B2 methylation statuses in the adrenal medulla (n = 4) and pheochromocytomas (n = 7) were examined. The expression of CYP11B2 in pheochromocytomas and non-functioning adenomas (NFAs) (n = 4) was also studied. Adrenals from five autopsy subjects were assessed for immunohistochemically defined adrenal zonation. We used laser capture microscopy to isolate DNA from each zone in adrenal tissues. CYP11B1 was predominantly unmethylated in the ZF but heavily methylated in the ZG and the ZR. In contrast, CYP11B2 was hypomethylated in the ZG compared with in the ZF and the ZR. In terms of the expression site and strength, the promoter methylation patterns for CYP11B2 and CYP11B1 showed capacities to express CYP11B enzymes. The DNA methylation patterns of the CYP11B2 and CYP11B1 promoters were closely associated with adrenal zonation. The unmethylated CpGs of CYP11B2 were found in the adrenal medulla and pheochromocytomas. Gene expression of CYP11B2 was detected in the pheochromocytomas. These results indicate the possibility that the synthesis of aldosterone occurs in the adrenal medulla. Further study is necessary to elucidate the pathophysiological roles for the synthesis of aldosterone in the adrenal medulla.

Activation of the renin–angiotensin–aldosterone system (RAAS) plays an important pathophysiological role in hypertension. Increased mRNA levels of the angiotensinogen angiotensin-converting enzyme, angiotensin type 1 receptor gene, Agtr1a, and the aldosterone synthase gene, CYP11B2, have been reported in the heart, blood vessels, and kidneys in salt-sensitive hypertension. However, the mechanism of gene regulation in each component of the RAAS in cardiovascular and renal tissues is unclear. Epigenetic mechanisms, which are important for regulating gene expression, include DNA methylation, histone post-translational modifications, and microRNA (miRNA) regulation. A close association exists between low DNA methylation at CEBP-binding sites and increased AGT expression in visceral adipose tissue and the heart of salt-sensitive hypertensive rats. Several miRNAs influence AGT expression and are associated with cardiovascular diseases. Expression of both ACE and ACE2 genes is regulated by DNA methylation, histone modifications, and miRNAs. Expression of both angiotensinogen and CYP11B2 is reversibly regulated by epigenetic modifications and is related to salt-sensitive hypertension. The mineralocorticoid receptor (MR) exists in cardiovascular and renal tissues, in which many miRNAs influence expression and contribute to the pathogenesis of hypertension. Expression of the 11beta-hydroxysteroid dehydrogenase type 2 (HSD11B2) gene is also regulated by methylation and miRNAs. Epigenetic regulation of renal and vascular HSD11B2 is an important pathogenetic mechanism for salt-sensitive hypertension.

Aldosterone and cortisol serve important roles in the pathogenesis of cardiovascular diseases and metabolic disorders. Epigenetics is a mechanism to control enzyme expression by genes without changing the gene sequence. Steroid hormone synthase gene expression is regulated by transcription factors specific to each gene, and methylation has been reported to be involved in steroid hormone production and disease. Angiotensin II or potassium regulates the aldosterone synthase gene, CYP11B2. The adrenocorticotropic hormone controls the 11b-hydroxylase, CYP11B1. DNA methylation negatively controls the CYP11B2 and CYP11B1 expression and dynamically changes the expression responsive to continuous stimulation of the promoter gene. Hypomethylation status of the CYP11B2 promoter region is seen in aldosterone-producing adenomas. Methylation of recognition sites of transcription factors, including cyclic AMP responsive element binding protein 1 or nerve growth factor-induced clone B, diminish their DNA-binding activity. A methyl-CpG-binding protein 2 cooperates directly with the methylated CpG dinucleotides of CYP11B2. A low-salt diet, treatment with angiotensin II, and potassium increase the CYP11B2 mRNA levels and induce DNA hypomethylation in the adrenal gland. A close association between a low DNA methylation ratio and an increased CYP11B1 expression is seen in Cushing’s adenoma and aldosterone-producing adenoma with autonomous cortisol secretion. Epigenetic control of CYP11B2 or CYP11B1 plays an important role in autonomic aldosterone or cortisol synthesis.

Therapeutic angiogenesis mediated by stem/progenitor cells is an attractive therapeutic option against cardiovascular disease (CVD). Adipose tissue (AT) can be safely obtained even in CVD patients with anti-platelet medications, and it is a readily available source of culture-expanded adipose-derived stem cells (ADSCs) for transplantation. Single-cell transcriptome enables us to screen all the surface markers at once, while conventional strategies have been limited for the number of target markers. Furthermore, gene profiling at single-cell resolution can be used for the quantification of each marker by how many favorable cells can be purified without mixing of detrimental cells. We aimed to identify and characterize a cell population with in vivo angiogenic potential by single-cell RNA sequencing (scRNA-seq) analysis and xenograft experiments. We revisited scRNA-seq datasets of single cell fraction from AT, bone-marrow (BM), and umbilical-cord blood (UCB, n=6/organ) to find cell populations with pro-angiogenic potential. Next, we collected AT from CVD patients (n=23) and used multicolor flow cytometry to quantify and sort the specific populations. PBS, the specific marker-negative and unsorted ADSCs were used as controls. Xenograft models of PKH26 pre-labeled human ADSC transplantation in limb ischemia were used to evaluate the lectin capillary density, PKH⁺ engrafted ADSCs, and blood flow recovery. Clustering divided CD45^–CD31^–CD34⁺ progenitor fraction into 3 clusters. We identified pro-/anti-angiogenic clusters based on the expressions of well-known pro-/anti-angiogenic factors. All genes encoding cell-surface proteins were compared in this functional clustering, resulted in 17 markers screened (Fig. 1A, B). Taken together with enrichment analysis, CD271⁺ cells showed predominant and pro-angiogenic gene profile from the other top candidates including CD36 and CD54 (Fig. 1C, D). Next, we evaluated the number and gene profile of CD271⁺ cells in well-known stem cell sources including BM and UCB. Surprisingly, the number of CD271 expressing cells were significantly lower and did not show angiogenic gene profile in BM and UCB (Fig. 2A). In analysis of AT from 23 CVD patients, CD271⁺ cells were significantly decreased by donor insulin resistance (Fig. 2B). Cell therapy using CD271⁺ ADSCs demonstrated in vivo angiogenic capacity compared to those of CD271^– ADSCs and PBS in limb ischemia model. Furthermore, CD271⁺ ADSC transplantation showed enhanced efficacy compared to unsorted ADSCs from the same donors (Fig. 2C–E). In this study, we identified CD271⁺ cell population in AT as an angiogenic cell population through scRNA-seq analysis and cell therapy experiments. AT obtained from donors without insulin resistance would be the most suitable for CD271⁺ ADSC isolation. CD271⁺ ADSC transplantation with a promising angiogenic capacity could contribute better cell-based therapy tackling CVD. Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science (JSPS) KAKENHI (Tokyo, Japan) Figure 1 Figure 2

Insulin oedema is a rare complication of insulin treatment characterised by an absence of heart, liver and renal involvement. Insulin oedema typically develops in the lower extremities or, less frequently, as generalised oedema after initiation of insulin therapy. We report a 59-year-old man with poorly controlled type 2 diabetes who developed oedema in his penis and scrotum accompanied by weight gain following intensive insulin therapy. His oedema improved after reduction of the daily insulin injection dose and treatment for urinary retention. Penile and scrotal oedema is a rare physical finding for the patient with diabetes. Therefore, in patients with poorly controlled diabetes who have started insulin therapy, physicians should pay attention to urinary retention and do not miss changes in weight gain or oedema in the lower body, including the perineal region.