Molecular and Cellular Endocrinology

Uterus globulin associated protein 1 (UGRP1) is a potential marker of progression of Graves' disease into hypothyroidism Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Zheng Zhou, Chun-Lin Zuo, Xue-Song Li, Xiao-Ping Ye, Qian-Yue Zhang, Ping Wang, Rong-Xin Zhang, Gang Chen, Jia-Lin Yang, Yue Chen, Qin-Yun Ma, Huai-Dong Song Abstract Approximately 20% of Graves' disease (GD) patients may result eventually in hypothyroidism in their natural course. Uterus globulin-associated protein 1 (UGRP1) was associated with GD in our previous study. Here we investigated the role of UGRP1 in the development of autoimmune thyroid disease (AITD). The results showed that UGRP1 was expressed in the thyrocytes of most Hashimoto's thyroiditis (HT) patients and a proportion of GD patients (293 HT and 198 GD). The pathologic features of UGRP1-positive thyrocytes resembled “Hürthle cells”, and were surrounded by infiltrated leukocytes. The positivity rate of TPOAb in UGRP1-positive GD patients was much higher than that in -negative GD patients. Moreover, UGRP1 was co-expressed with Fas and HLA-DR in the thyrocytes of AITD patients. We also found IL-1β but not Th1 or Th2 cytokines was able to upregulate the expression of UGRP1. Our findings indicated that UGRP1 may be a novel marker in thyrocytes to predict GD patients who develop hypothyroidism.

Klotho inhibits PKCα/p66SHC-mediated podocyte injury in diabetic nephropathy Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Wei Jiang, Tangli Xiao, Wenhao Han, Jiachuan Xiong, Ting He, Yong Liu, Yinghui Huang, Ke Yang, Xianjin Bi, Xinli Xu, Yanlin Yu, Yan Li, Jun Gu, Jingbo Zhang, Yunjian Huang, Bo Zhang, Jinghong Zhao Abstract Diabetic nephropathy (DN) is a progressive disease, the main pathogeny of which is podocyte injury. As a calcium-dependent serine/threonine protein kinase involved in podocyte injury, protein kinase C isoform α (PKCα) was reported to regulate the phosphorylation of p66SHC. However, the role of PKCα/p66SHC in DN remains unknown. Klotho, an anti-aging protein with critical roles in protecting kidney, is expressed predominantly in the kidney and secreted in the blood. Nonetheless, the mechanism underlying amelioration of podocyte injury by Klotho in DN remains unclear. Our data showed that Klotho was decreased in STZ-treated mice and was further declined in diabetic KL ± mice. As expected, Klotho deficiency aggravated diabetes-induced proteinuria and podocyte injury, accompanied by the activation of PKCα and p66SHC. In contrast, overexpression of Klotho partially ameliorated PKCα/p66SHC-mediated podocyte injury and proteinuria. In addition, in vitro experiments showed that activation of PKCα and subsequently increased intracellular reactive oxygen species (ROS) was involved in podocytic apoptosis induced by high glucose (HG), which could be partially reversed by Klotho. Hence, we conclude that Klotho might inhibit PKCα/p66SHC-mediated podocyte injury in diabetic nephropathy. Graphical abstract Schematic diagram of the proposed mechanism. HG promotes calcium influx by activating calcium channel (e.g. TRCPC6) in podocytes. Excess intracellular calcium activates PKCα which then contributes to the phosphorylation of p66SHC. Phosphorylated p66SHC then enters mitochondria by altering its configuration. Thereafter, the altered configuration of p66SHC oxidizes cytochrome c (Cytc) releasing a large amount of reactive oxygen species (ROS). Continuous generation of ROS eventually leads to cellular injury and apoptosis of podocytes. However, Klotho (sKL) can function by inhibiting calcium influx induced by HG. SKL reduces intracellular calcium to inhibit PKCα/p66SHC. Therefore, Klotho inhibits continuous generation of ROS eventually ameliorating injury and apoptosis of podocytes.

Quantitative proteomics reveals novel interaction partners of Rac1 in pancreatic β-cells: Evidence for increased interaction with Rac1 under hyperglycemic conditions Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Divyasri Damacharla, Vijayalakshmi Thamilselvan, Xiangmin Zhang, Aktham Mestareehi, Zhengping Yi, Anjaneyulu Kowluru Abstract Rac1, a small G protein, regulates physiological insulin secretion from the pancreatic β-cell. Interestingly, Rac1 has also been implicated in the onset of metabolic dysfunction of the β-cell under the duress of hyperglycemia (HG). This study is aimed at the identification of interaction partners of Rac1 in β-cells under basal and HG conditions. Using co-immunoprecipitation and UPLC-ESI-MS/MS, we identified 324 Rac1 interaction partners in INS-1832/13 cells, which represent the largest Rac1 interactome to date. Furthermore, we identified 27 interaction partners that exhibited increased association with Rac1 in β-cells exposed to HG. Western blotting (INS-1832/13 cells, rat islets and human islets) and co-immunoprecipitation (INS-1832/13 cells) further validated the identity of these Rac1 interaction partners including regulators of GPCR-G protein-effector coupling in the islet. These data form the basis for future investigations on contributory roles of these Rac1-specific signaling pathways in islet β-cell function in health and diabetes. Graphical abstract

Altered miR-186 and miR-135a contribute to granulosa cell dysfunction by targeting ESR2: A possible role in polycystic ovary syndrome Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Yuxia Song, Guo Yu, Yungai Xiang, Yan Li, Lijing Wan, Li Tan Abstract MicroRNAs (miRNAs) are a group of negative regulators of gene expression that function at the posttranscriptional level. Dysregulation of miRNAs is involved in many pathophysiological processes, including polycystic ovary syndrome (PCOS). In this study, we first detected the expression levels of 6 candidate miRNA in granulosa cells (GCs) from 63 women with PCOS and 20 healthy controls. We found that miR-186 and miR-135a were overexpressed in GCs from PCOS patients. Subsequently, the direct targets of miR-186 and miR-135a were predicted using bioinformatics analysis and verified by luciferase assays and immunoblotting. The present study determined that miR-186 and miR-135a repressed ESR2 expression in GCs, which further inhibited CDKN1A expression, promoted GC proliferation and repressed GC apoptosis. Meanwhile, the levels of miR-186 and miR-135a in GCs were found to positively correlate with serum estradiol levels in patients with PCOS. Furthermore, estradiol treatment directly increased miR-186 and miR-135a levels in KGN and primary GCs, which provides new insight into understanding the pathophysiology of PCOS.

Empagliflozin improves primary haemodynamic parameters and attenuates the development of atherosclerosis in high fat diet fed APOE knockout mice Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Georgios K. Dimitriadis, Narjes Nasiri-Ansari, Georgios Agrogiannis, Ioannis D. Kostakis, Manpal S. Randeva, Nikolaos Nikiteas, Vanlata H. Patel, Gregory Kaltsas, Athanasios G. Papavassiliou, Harpal S. Randeva, Eva Kassi Abstract The effects of long-term treatment with empagliflozin on biochemical and immunohistochemical markers related to atherosclerosis and atherosclerosis development in the aorta of apolipoprotein E knockout [Apo-E (−/−)] mice were evaluated in this study. Empagliflozin-treated mice had lower total cholesterol (P < 0.05), fasting glucose (P < 0.01), heart rate (P < 0.01) and diastolic blood pressure (DBP) (P < 0.05) compared to controls. Histomorphometry revealed reduced atherosclerotic lesion progress approaching statistical significance (P = 0.06) and approximately 50% wider lumen area for the Empagliflozin treated mice group. Although empagliflozin significantly reduced Vcam-1 and Mcp-1 (P < 0.05, P < 0.01, respectively) and marginally induced Timp-1 and Timp-2 mRNA expression (P < 0.08, P = 0.1 respectively), immunohistochemistry revealed a marginal reduction in VCAM-1 and MMP-9 (P = 0.1) without affecting the expression of TIMP-2 and MCP-1 in atherosclerotic lesions. Empagliflozin improves primary haemodynamic parameters and attenuates the progression of atherosclerosis by reducing hyperlipidemia and hyperglycemia, while direct actions in aorta vessel mediated via SGLT-1 are strongly hypothesized.

The acute effects of hydrocortisone on cardiac electrocardiography, action potentials, intracellular calcium, and contraction: The role of protein kinase C Publication date: 20 August 2019 Source: Molecular and Cellular Endocrinology, Volume 494 Author(s): Mi-Hyeong Park, Seo-In Park, Jong-Hui Kim, Jing Yu, Eun Hye Lee, Su Ryeon Seo, Su-Hyun Jo Abstract Hydrocortisone exerts adverse effects on various organs, including the heart. This study investigated the still unclear effects of hydrocortisone on electrophysiological and biochemical aspects of cardiac excitation–contraction coupling. In guinea pigs’ hearts, hydrocortisone administration reduced the QT interval of ECG and the action potential duration (APD). In guinea pig ventricular myocytes, hydrocortisone reduced contraction and Ca2+ transient amplitudes. These reductions and the effects on APD were prevented by pretreatment with the protein kinase C (PKC) inhibitor staurosporine. In an overexpression system of Xenopus oocytes, hydrocortisone increased hERG K+ currents and reduced Kv1.5 K+ currents; these effects were negated by pretreatment with staurosporine. Western blot analysis revealed dose- and time-dependent changes in PKCα/βII, PKCε, and PKCγ phosphorylation by hydrocortisone in guinea pig ventricular myocytes. Therefore, hydrocortisone can acutely affect cardiac excitation–contraction coupling, including ion channel activity, APD, ECG, Ca2+transients, and contraction, possibly via biochemical changes in PKC.

ALK4-SMAD2/3-SMAD4 signaling mediates the activin A-induced suppression of PTX3 in human granulosa-lutein cells Publication date: 1 August 2019 Source: Molecular and Cellular Endocrinology, Volume 493 Author(s): Chang Liu, Hsun-Ming Chang, Yuyin Yi, Ying Fang, Feiyan Zhao, Peter C.K. Leung, Xiaokui Yang Abstract As one of the members of the transforming growth factor-β (TGF-β) superfamily, activin A plays an important role in regulating follicular development and oocyte maturation. Pentraxin 3 (PTX3) is the key component that promotes the process of cumulus expansion during mammalian ovulation. At present, the regulation of PTX3 expression in human granulosa cells remains largely unknown. This study aimed to examine the effects of activin A on the expression of PTX3 in human granulosa-lutein (hGL) cells and to investigate the underlying molecular mechanisms. Using an established immortalized hGL cell line (SVOG) and primary hGL cells as study models, we demonstrated that activin A significantly increased the phosphorylation of SMAD2 and SMAD3, which suppressed the expression of PTX3 at both the mRNA and protein levels. Additionally, these effects induced by activin A were completely reversed by pretreatment with the TGF-β type I receptor inhibitor SB431542 and knockdown of ALK4. Furthermore, knockdown of SMAD2, SMAD3, or SMAD4 completely reversed the activin A-induced suppressive effects on PTX3 expression. Notably, the ChIP analyses demonstrated that phosphorylated SMADs could bind to human PTX3 promoter. Collectively, our results showed that the ALK4-SMAD2/3-SMAD4 signaling pathway most likely mediates the suppressive effect of activin A on PTX3 expression in hGL cells.

Defective endoplasmic reticulum export causes proinsulin misfolding in pancreatic β cells Publication date: 1 August 2019 Source: Molecular and Cellular Endocrinology, Volume 493 Author(s): Ruimin Zhu, Xin Li, Jialu Xu, Cesar Barrabi, Dilini Kekulandara, James Woods, Xuequn Chen, Ming Liu Abstract Endoplasmic reticulum (ER) homeostasis is essential for cell function. Increasing evidence indicates that, efficient protein ER export is important for ER homeostasis. However, the consequence of impaired ER export remains largely unknown. Herein, we found that defective ER protein transport caused by either Sar1 mutants or brefeldin A impaired proinsulin oxidative folding in the ER of β-cells. Misfolded proinsulin formed aberrant disulfide-linked dimers and high molecular weight proinsulin complexes, and induced ER stress. Limiting proinsulin load to the ER alleviated ER stress, indicating that misfolded proinsulin is a direct cause of ER stress. This study revealed significance of efficient ER export in maintaining ER protein homeostasis and native folding of proinsulin. Given the fact that proinsulin misfolding plays an important role in diabetes, this study suggests that enhancing ER export may be a potential therapeutic target to prevent/delay β-cell failure caused by proinsulin misfolding and ER stress.

The development of the serotonergic and dopaminergic systems during chicken mid-late embryogenesis Publication date: 1 August 2019 Source: Molecular and Cellular Endocrinology, Volume 493 Author(s): Xiaohong Huang, Shihuan Kuang, Todd J. Applegate, Tsang-long Lin, Heng-wei Cheng Abstract Serotonin (5-HT) acts as a morphogen influencing embryonic brain development, and as a neurotransmitter regulating multiple biological functions with lifelong effects on animal physical, physiological and mental health, especially during the rapid growth phase prior to birth when embryos face many challenges to reach structural and functional completion. In this study, the development of the serotoninergic (5-HTergic) system and its modulatory effect on the dopaminergic (DAergic) system and related neural circuits were investigated during the mid-late embryogenesis, embryonic day (E)12-E20, in the chicken's brain. During 5-HTergic neuronal maturation, a growth-related anatomical and functional remodeling was highlighted: the 5-HT neurons continuously grew during E12-E20 except for a remarkable regression during E14-E16. Correspondingly, there was a time-dependent change in the 5-HT synthetic capacity. Specifically, 5-HT concentrations in the raphe nuclei increased from E12 to E14, reaching a first plateau during E14-E16, then continuously increased up to E19, and reaching a second plateau between E19-E20. The second plateau of the 5-HT concentration was in correspondence with the establishment of the 5-HTergic autoregulatory loop during E19-E20 and the development of the DAergic system. The DA concentrations remained unchanged from E12 to E16, then started to increase at E16, reaching a maximum at E19, and diminished before hatching. The unique developing time sequence between the 5-HTergic and DAergic systems suggests that the 5-HTergic system may play a critical role in forming the 5-HT – DA neural circuit during chicken embryogenesis. These results provide new insights for understanding the functional organization of the 5-HTergic system during embryonic development and raise the possibility that prenatally modulating the 5-HTergic system may lead to long-lasting brain structural and functional alterations. Graphical abstract

Correlation between renin-angiotensin system (RAS) related genes, type 2 diabetes, and cancer: Insights from metanalysis of transcriptomics data Publication date: 1 August 2019 Source: Molecular and Cellular Endocrinology, Volume 493 Author(s): Luciana Xavier Pereira, Laryssa Cristina Alves da Silva, Alexya de Oliveira Feitosa, Ricardo Jansen Santos Ferreira, Ana Kelly Fernandes Duarte, Valdemir da Conceição, Carolinne de Sales Marques, Amanda Karine Barros Ferreira Rodrigues, Bruna Del Vechio Koike, Aline Cavalcante de Queiroz, Talita Antunes Guimaraes, Carlos Dornels Freire de Souza, Carlos Alberto de Carvalho Fraga Abstract Although studies have provided significant evidence about the role of RAS in mediating cancer risk in type 2 diabetes mellitus (DM), conclusions about the central molecular mechanisms underlying this disease remain to be reached, because this type of information requires an integrative multi-omics approach. In the current study, meta-analysis was performed on type 2 diabetes and breast, bladder, liver, pancreas, colon and rectum cancer-associated transcriptome data, and reporter biomolecules were identified at RNA, protein, and metabolite levels using the integration of gene expression profiles with genome-scale biomolecular networks in diabetes samples. This approach revealed that RAS biomarkers could be associated with cancer initiation and progression, which include metabolites (particularly, aminoacyl-tRNA biosynthesis and ABC transporters) as novel biomarker candidates and potential therapeutic targets. We detected downregulation and upregulation of differentially expressed genes (DEGs) in blood, pancreatic islets, liver and skeletal muscle from normal and diabetic patients. DEGs were combined with 211 renin-angiotensin-system related genes. Upregulated genes were enriched using Pathway analysis of cancer in pancreatic islets, blood and skeletal muscle samples. It seems that the changes in mRNA are contributing to the phenotypic changes in carcinogenesis, or that they are as a result of the phenotypic changes associated with the malignant transformation. Our analyses showed that Ctsg and Ednrb are downregulated in cancer samples. However, by immunohistochemistry experiments we observed that EDNRB protein showed increased expression in tumor samples. It is true that alterations in mRNA expression do not always reflect alterations in protein expression, since post-translational changes can occur in proteins. In this study, we report valuable data for further experimental and clinical analysis, because the proposed biomolecules have significant potential as systems biomarkers for screening or for therapeutic purposes in type 2 diabetes and cancer-associated pathways.