Lysine-specific demethylase 1 as a corepressor of mineralocorticoid receptor.

Mineralocorticoid receptor (MR) and its ligand aldosterone play a central role in controlling blood pressure by promoting sodium reabsorption in the kidney. Coregulators are recruited to regulate the activation of steroid hormone receptors. In our previous study, we identified several new candidates for MR coregulators through liquid chromatography-tandem mass spectrometry analysis using a biochemical approach. Lysine-specific demethylase 1 (LSD1) was identified as a candidate. The relationship between LSD1 and salt-sensitive hypertension has been reported; however, the role of MR in this condition is largely unknown. Here, we investigated the functions of LSD1 as a coregulator of MR. First, a coimmunoprecipitation assay using HEK293F cells showed specific interactions between MR and LSD1. A chromatin immunoprecipitation study demonstrated LSD1 recruitment to the gene promoter of epithelial Na+ channel (ENaC), a target gene of MR. Reduced LSD1 expression by treatment with shRNA potentiated the hormonal activation of ENaC and serum/glucocorticoid-regulated kinase 1, another target gene of MR, indicating that LSD1 is a corepressor of MR. In an animal study, mice with kidney-specific LSD1 knockout (LSD1flox/floxKSP-Cre mice) developed hypertension after a high-salt diet without elevation of aldosterone levels, which was counteracted by cotreatment with spironolactone, an MR antagonist. In conclusion, our in vitro and in vivo studies demonstrated that LSD1 is a newly identified corepressor of MR.

Amiodarone-induced multiple organ damage in an Alström syndrome patient with end-stage renal disease and hepatic cirrhosis.

Alström syndrome (AS) is an extremely rare disease accompanied by blindness, hearing loss, obesity, type 2 diabetes, dilated cardiomyopathy, and progressive hepatic and renal dysfunction. The life span of AS patients rarely exceeds 50 years, and thus there are very few reports describing the implementation of renal replacement therapy for these patients. We here report a case of AS patient who exhibited dilated cardiomyopathy, end-stage renal disease, and hepatic cirrhosis. He underwent hemodialysis therapy more than 3 years. Although he eventually died of amiodarone-induced multiple organ damage in the lungs and liver, the present case suggests that hemodialysis therapy can be a choice of renal replacement therapy for AS patients with end-stage renal disease.

Difficulty in managing nephrotic syndrome-associated cerebral venous thrombosis.

Thromboembolism is one of the most serious complications of nephrotic syndrome (NS). Although the occurrence of renal vein thrombosis or deep vein thrombosis is well recognized in NS patients, they rarely develop cerebral venous thrombosis (CVT). The mortality rate of CVT patients is still approximately 10%, and 6-10% of patients who survive have a severe and permanent disability. Herein, we report the case of a 26-year-old woman with multiple thrombotic risk factors, including the presence of NS, use of oral contraceptives, smoking, and alcohol consumption who developed wide-range CVT. Undetermined fraction heparin, albumin and AT-III transfusion, and direct mechanical catheter thrombectomy were insufficient for the improvement of CVT. However, CVT eventually improved along with the remission of NS by prednisolone administration. This process indicates that in the management of CVT associated with NS, it is crucial to control the activity of NS. Currently, knowledge on the treatment for NS associated with CVT is limited, and this is a subject of urgent investigation.