Matsuura et al Role of PHD2 in Adipocytes 2079Several cell culture studies have revealed that hypoxia and HIF convert cell metabolism that is dependent on aerobic glucose oxidation and fatty acid synthesis into that which is dependent on anaerobic glycolysis. HIF not only upregulates a series of glycolytic enzymes 15,16 but also actively inhibits oxidative phosphorylation in mitochondria by inducing pyruvate dehydrogenase kinase 1 (PDK1).17,18 PDK1 inhibits pyruvate dehydrogenase activity and consequently reduces the conversion of pyruvate to acetyl CoA, an essential substrate for oxidative phosphorylation. 17,18 In addition, HIF inhibits adipogenesis by inducing DEC1/Stra13. 13 These HIF-induced metabolic alterations such as increased glucose consumption and less fatty acid synthesis might be beneficial for nutrient excess in obese or diabetic subjects. Although HIF could be a potential therapeutic target, direct manipulation of HIF is often difficult in vivo. In contrast, PHD is an ideal target to manipulate HIF levels, and several chemical inhibitors of PHD have been developed. 19 However, the role of adipocyte PHD in the development of obesity-induced glucose intolerance has not been determined. In the present study, we generated mice lacking PHD2, also known as Egl 9 homolog1 (EglN1) in adipocytes, because PHD2 is the most crucial isoform to regulate HIF level in vitro 20 and in vivo 21 among 3 PHD isoforms (PHD1, PHD2, and PHD3). We found that PHD2 deletion in adipocyte attenuates weight gain and alleviates glucose intolerance induced by a high-fat diet (HFD). MethodsAdditional details of the experimental procedures are included in the online-only Data Supplement.All animal procedures were approved by the Animal Care and Use Committee of Kyushu University and conducted in accordance with the institutional guidelines. Previously generated Phd2-floxed mice f/f mice. Phd2 f/f mice served as controls. These mice were fed an HFD containing 60% kcal fat (High Fat Diet 32, Clea Japan, Inc) from 12 to 18 weeks of age. Mice 12 and 18 weeks of age were analyzed. Preparation of cell lysate and total RNA, Western blot analysis, quantitative reverse transcription-polymerase chain reaction, luciferase assay, and histological/immunohistochemical analysis were performed using conventional methods. The primer sequences for quantitative reverse transcription-polymerase chain reaction are shown in Table I Figure 1A and Figure IA in the online-only Data Supplement). Expression of PHD2 in heart and bone marrowderived macrophages was slightly reduced. We did not find any apparent abnormalities in the appearance in Phd2 Figure 2B and 2D). However, the extent of HFD-induced adipocyte hypertrophy was significantly reduced in Phd2 f/f /aP2-Cre mice compared with control mice (Figure 2C and 2D). A detailed analysis of the size distribution of the adipocytes revealed that WAT from controls contained a greater number of larger adipocytes (>10 000 μm 2 ) than that Enhanced Angiogenesis in WAT From HFD-Fed Phd2f/f /aP2-Cre Mice B...
BackgroundHypertension induces cardiovascular hypertrophy and fibrosis. Infiltrated macrophages are critically involved in this process. We recently reported that inhibition of prolyl hydroxylase domain protein 2 (PHD2), which hydroxylates the proline residues of hypoxia‐inducible factor‐α (HIF‐α) and thereby induces HIF‐α degradation, suppressed inflammatory responses in macrophages. We examined whether myeloid‐specific Phd2 deletion affects hypertension‐induced cardiovascular remodeling.Methods and ResultsMyeloid‐specific PHD2‐deficient mice (MyPHD2KO) were generated by crossing Phd2‐floxed mice with LysM‐Cre transgenic mice, resulting in the accumulation of HIF‐1α and HIF‐2α in macrophage. Eight‐ to ten‐week‐old mice were given NG‐nitro‐L‐arginine methyl ester (L‐NAME), a nitric oxide synthase inhibitor, and Angiotensin II (Ang II) infusion. L‐NAME/Ang II comparably increased systolic blood pressure in control and MyPHD2KO mice. However, MyPHD2KO mice showed less aortic medial and adventitial thickening, and macrophage infiltration. Cardiac interstitial fibrosis and myocyte hypertrophy were also significantly ameliorated in MyPHD2KO mice. Transforming growth factor‐β and collagen expression were decreased in the aorta and heart from MyPHD2KO mice. Echocardiographic analysis showed that left ventricular hypertrophy and reduced ejection fraction induced by L‐NAME/Ang II treatment in control mice were not observed in MyPHD2KO mice. Administration of digoxin that inhibits HIF‐α synthesis to L‐NAME/Ang II‐treated MyPHD2KO mice reversed these beneficial features.ConclusionsPhd2 deletion in myeloid lineage attenuates hypertensive cardiovascular hypertrophy and fibrosis, which may be mediated by decreased inflammation‐ and fibrosis‐associated gene expression in macrophages. PHD2 in myeloid lineage plays a critical role in hypertensive cardiovascular remodeling.
Rare inherited variations in multiplex families with autism spectrum disorder (ASD) are suggested to play a major role in the genetic etiology of ASD. To further investigate the role of rare inherited variations, we performed whole-exome sequencing (WES) in two families, each with three affected siblings. We also performed a two-stage follow-up case-control study in a Japanese population. WES of the six affected siblings identified six novel rare missense variations. Among these variations, CLN8 R24H was inherited in one family by three affected siblings from an affected father and thus co-segregated with ASD. In the first stage of the follow-up study, we genotyped the six novel rare missense variations identified by WES in 241 patients and 667 controls (the Niigata sample). Only CLN8 R24H had higher mutant allele frequencies in patients (1/482) compared with controls (1/1334). In the second stage, this variation was further genotyped, yet was not detected in a sample of 309 patients and 350 controls (the Nagoya sample). In the combined Niigata and Nagoya samples, there was no significant association (odds ratio = 1.8, 95% confidence interval = 0.1–29.6). These results suggest that CLN8 R24H plays a role in the genetic etiology of ASD, at least in a subset of ASD patients.
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