Function of CYP11A1 in the mitochondria

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Yu Chien, Karen Rosal, Bon-chu Chung
Steroids are synthesized from the adrenal glands and gonads by enzymes of the cytochromes P450 and hydroxysteroid dehydrogenase in nature. These enzymes are located in the membrane of endoplasmic reticulum and mitochondria to catalyze redox reactions using electrons transported from the membrane. In the mitochondria, steroidogenic enzymes are inserted into the inner membrane with the bulk of the protein facing the matrix. They are not only important for steroid biosynthesis, their presence also affects mitochondrial morphology. Mitochondria undergo constant fission and fusion; they play important roles in energy production, apoptosis, and metabolism. Their defects often lead to human diseases. Mitochondrial cristae are usually lamellar in shape, but can also assume different shapes. Cristae in the mitochondria of steroidogenic cells are tubular-vesicular in shape. This cristae shape is also related to the degree of steroidogenic cell differentiation. Steroidogenic enzymes in the mitochondria appear to have a dual role in shaping the morphology of mitochondria and in steroid production.



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Structural insights into the function of steroidogenic cytochrome P450 17A1

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Rahul Yadav, Elyse M. Petrunak, D. Fernando Estrada, Emily E. Scott
Cytochrome P450 17A1 (CYP17A1) operates at the core of human steroidogenesis, directing precursors into mineralocorticoids, glucocorticoids, or sex steroids. Although the 17α−hydroxylase and 17,20-lyase activities of this dual function enzyme have been investigated extensively, until recently no CYP17A1 structures were available to inform our understanding. Structures of CYP17A1 with a range of steroidal inhibitors and substrates are now available. This review relates functional knowledge of this enzyme to structural features defining the selective differentiation between its various substrates. While both hydroxylase and lyase substrates have similar orientations with respect to the heme, subtle differences in hydrogen bonding between CYP17A1 and the C3 substituent at the opposite end of ligands appear to correlate with differential substrate utilization and product formation. Complementary structural information from solution NMR supports cytochrome b5 allosteric modulation of the lyase reaction, implicating regions involved in ligand access to the otherwise buried active site.



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The metabolic fate and receptor interaction of 16α-hydroxyprogesterone and its 5α-reduced metabolite, 16α-hydroxy-dihydroprogesterone

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Desmaré van Rooyen, Therina du Toit, Renate Louw-du Toit, Donita Africander, Pieter Swart, Amanda C. Swart
16α-hydroxyprogesterone (16OHP4) is not well characterised in terms of metabolism and receptor interaction. We therefore investigated its metabolism by adrenal CYP11B and peripheral steroidogenic enzymes, SRD5A and AKR1C2. UHPLC-MS/MS analyses identified novel steroids: the biosynthesis of 4-pregnen-11β,16α-diol-3,20-dione catalysed by CYP11B2; the 5α-reduction of the latter and 16OHP4 catalysed by SRD5A yielding 5α-pregnan-11β,16α-diol-3,20-diovne and 5α-pregnan-16α-ol-3,20-dione (16OH-DHP4); and 16OH-DHP4 converted by AKR1C2 to 5α-pregnan-3α,16α-diol-20-one. Receptor studies showed 16OHP4, 16OH-DHP4, progesterone and dihydroprogesterone (DHP4) were weak partial AR agonists; 16OHP4, 16OH-DHP4 and DHP4 exhibited weak partial agonist activity towards PR-B with DHP4 also exhibiting partial agonist activity towards PR-A. Data showed that while the 5α-reduction of P4 decreased PR activation significantly, 16OHP4 and 16OH-DHP4 exhibited comparable receptor activation. Although the clinical relevance of 16OHP4 remains unclear the elevated 16OHP4 levels characteristic of 21OHD, CAH, PCOS, prostate cancer, testicular feminization syndrome and cryptorchidism likely contribute towards these clinical conditions, inducing receptor-activated target genes.



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Endothelial cells regulate β-catenin activity in adrenocortical cells via secretion of basic fibroblast growth factor

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Carolin Schwafertz, Sven Schinner, Markus C. Kühn, Matthias Haase, Amelie Asmus, Birgit Mülders-Opgenoorth, Ishrath Ansurudeen, Peter J. Hornsby, Henning Morawietz, Elke Oetjen, Matthias Schott, Holger S. Willenberg
Endothelial cell-derived products influence the synthesis of aldosterone and cortisol in human adrenocortical cells by modulating proteins such as steroidogenic acute-regulatory (StAR) protein, steroidogenic factor (SF)-1 and CITED2. However, the potential endothelial cell-derived factors that mediate this effect are still unknown. The current study was perfomed to look into the control of β-catenin activity by endothelial cell-derived factors and to identify a mechanism by which they affect β-catenin activity in adrenocortical NCIH295R cells.Using reporter gene assays and Western blotting, we found that endothelial cell-conditioned medium (ECCM) led to nuclear translocation of β-catenin and an increase in β-catenin-dependent transcription that could be blocked by U0126, an inhibitor of the mitogen-activated protein kinase pathway. Furthermore, we found that a receptor tyrosin kinase (RTK) was involved in ECCM-induced β-catenin-dependent transcription. Through selective inhibition of RTK using Su5402, it was shown that receptors responding to basic fibroblast growth factor (bFGF) mediate the action of ECCM.Adrenocortical cells treated with bFGF showed a significant greater level of bFGF mRNA. In addition, HUVECs secrete bFGF in a density-dependent manner. In conclusion, the data suggest that endothelial cells regulate β-catenin activity in adrenocortical cells also via secretion of basic fibroblast growth factor.

Graphical abstract

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Immunohistochemistry of aldosterone synthase leads the way to the pathogenesis of primary aldosteronism

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Koshiro Nishimoto, Minae Koga, Tsugio Seki, Kenji Oki, Elise P. Gomez-Sanchez, Celso E. Gomez-Sanchez, Mitsuhide Naruse, Tomokazu Sakaguchi, Shinya Morita, Takeo Kosaka, Mototsugu Oya, Tadashi Ogishima, Masanori Yasuda, Makoto Suematsu, Yasuaki Kabe, Masao Omura, Tetsuo Nishikawa, Kuniaki Mukai
Our group previously purified human and rat aldosterone synthase (CYP11B2 and Cyp11b2, respectively) from their adrenals and verified that it is distinct from steroid 11β-hydroxylase (CYP11B1 or Cyp11b1), the cortisol- or corticosterone-synthesizing enzyme. We now describe their distributions immunohistochemically with specific antibodies. In rats, there is layered functional zonation with the Cyp11b2-positive zona glomerulosa (ZG), Cyp11b1-positive zona fasciculata (ZF), and Cyp11b2/Cyp11b1-negative undifferentiated zone between the ZG and ZF. In human infants and children (<12 years old), the functional zonation is similar to that in rats. In adults, the adrenal cortex remodels and subcapsular aldosterone-producing cell clusters (APCCs) replace the continuous ZG layer. We recently reported possible APCC-to-APA transitional lesions (pAATLs) in 2 cases of unilateral multiple adrenocortical micro-nodules. In this review, we present 4 additional cases of primary aldosteronism, from which the extracted adrenals contain pAATLs, with results of next generation sequencing for these lesions. Immunohistochemistry for CYP11B2 and CYP11B1 has become an important tool for the diagnosis of and research on adrenocortical pathological conditions and suggests that APCCs may be the origin of aldosterone-producing adenoma.



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Analysis of ARMC5 expression in human tissues

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Annabel Berthon, Fabio Faucz, Jerome Bertherat, Constantine A. Stratakis
Mutations in ARMC5 gene have been recently identified as the main cause of Primary Macronodular Adrenocortical Hyperplasia (PMAH). PMAH patients have an ARMC5 germline mutation and, in addition, somatic tissue-specific mutations. This is consistent with the two-hit hypothesis of tumorigenesis and suggests that ARMC5 may be a tumor suppressor gene. As its function is still unclear, we analyzed the expression of the four ARMC5 isoforms in 46 normal human tissues. This showed that at least one ARMC5 isoform is ubiquitously expressed throughout the body; however, only 7 tissues expressed all isoforms, including the adrenal gland and the brain. Interestingly, the highest expression for ARMC5 in the brain is in the pituitary gland. The isoform ARMC5-003 was present in most endocrine tissues including the pituitary, adrenal glands and the pancreas. In this report, we present new data about the ARMC5 expression pattern in human tissues; its wide expression in brain, pituitary gland and other tissues suggest that mutations may be responsible for additional pathologies, beyond what is already known in PMAH and meningiomas.



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Seventeenth Conference on the Adrenal Cortex (Adrenal 2016) Boston, MA, March 28–31, 2016

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Bernard P. Schimmer, Raymond J. Rodgers




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Adrenal cortical and chromaffin stem cells: Is there a common progeny related to stress adaptation?

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Charlotte Steenblock, Maria F. Rubin de Celis, Andreas Androutsellis-Theotokis, Mariko Sue, Luis F. Delgadillo Silva, Graeme Eisenhofer, Cynthia L. Andoniadou, Stefan R. Bornstein
The adrenal gland is a highly plastic organ with the capacity to adapt the body homeostasis to different physiological needs. The existence of stem-like cells in the adrenal cortex has been revealed in many studies. Recently, we identified and characterized in mice a pool of glia-like multipotent Nestin-expressing progenitor cells, which contributes to the plasticity of the adrenal medulla. In addition, we found that these Nestin progenitors are actively involved in the stress response by giving rise to chromaffin cells. Interestingly, we also observed a Nestin-GFP-positive cell population located under the adrenal capsule and scattered through the cortex. In this article, we discuss the possibility of a common progenitor giving rise to subpopulations of cells both in the adrenal cortex and medulla, the isolation and characterization of this progenitor as well as its clinical potential in transplantation therapies and in pathophysiology.



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Introduction to the 2016 Keith L. Parker Memorial Lecturer: Douglas M. Stocco, Ph.D.

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Walter L. Miller
Douglas M. (Doug) Stocco is Professor Emeritus at Texas Tech University Health Sciences Center in Lubbock, TX, and is internationally renowned for his work characterizing the steroidogenic acute regulatory protein, StAR. Stocco's laboratory isolated and cloned StAR from mouse Leydig MA-10 cells, collaborated on the demonstration that StAR mutations cause congenital lipoid adrenal hyperplasia, and delineated much of what is known about the intracellular pathways that regulate its production. This work resolved a decades-long quest to identify the mechanism underlying the acute regulation of steroidogenesis.



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The ER-mitochondria couple: In life and death from steroidogenesis to tumorigenesis

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Mabrouka Doghman-Bouguerra, Enzo Lalli
Steroidogenesis is a multistep process where interorganelle communications between the endoplasmic reticulum and mitochondria are critical. These intimate interactions physically occur through the Mitochondria-Associated ER membranes called MAMs. MAMs play important roles in mitochondrial morphology and in many cellular functions ranging from lipid metabolism, to calcium signaling and apoptosis together with a critical effect on steroidogenesis. Moreover, our recent characterization of new MAM resident proteins in adrenocortical cells extends the function of MAM in the mechanism of resistance of cancer cells to apoptotic stimuli and offers new perspectives in targeted therapeutic approaches for adrenocortical tumorigenesis.



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A brief history of the search for the protein(s) involved in the acute regulation of steroidogenesis

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Douglas M. Stocco, Amy H. Zhao, Lan N. Tu, Kanako Morohaku, Vimal Selvaraj
The synthesis of steroid hormones occurs in specific cells and tissues in the body in response to trophic hormones and other signals. In order to synthesize steroids de novo, cholesterol, the precursor of all steroid hormones, must be mobilized from cellular stores to the inner mitochondrial membrane (IMM) to be converted into the first steroid formed, pregnenolone. This delivery of cholesterol to the IMM is the rate-limiting step in this process, and has long been known to require the rapid synthesis of a new protein(s) in response to stimulation. Although several possibilities for this protein have arisen over the past few decades, most of the recent attention to fill this role has centered on the candidacies of the proteins the Translocator Protein (TSPO) and the Steroidogenic Acute Regulatory Protein (StAR). In this review, the process of regulating steroidogenesis is briefly described, the characteristics of the candidate proteins and the data supporting their candidacies summarized, and some recent findings that propose a serious challenge for the role of TSPO in this process are discussed.



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SNAREs and cholesterol movement for steroidogenesis

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Fredric B. Kraemer, Wen-Jun Shen, Salman Azhar
Steroidogenesis is a complex process through which cholesterol traffics to mitochondria and is converted via a series of enzymatic steps to steroid hormones. Although the rate-limiting step in this process is the movement of cholesterol from the outer to the inner mitochondrial membrane via the actions of StAR, a continuous supply of cholesterol must be delivered to the outer mitochondrial membrane during active steroidogenesis and this is derived from multiple sources, including lipoprotein uptake, endogenous cholesterol synthesis and release from stores within cytoplasmic lipid droplets. A number of mechanisms have been suggested to contribute to cholesterol trafficking to mitochondria; however, there is no definitive consensus and this is particularly so in regards to trafficking from cytoplasmic lipid droplets. In this paper we review experiments in which we have surveyed the expression of SNARE proteins in steroidogenic tissue and cells and examined the role of SNAREs in mediating cholesterol movement from lipid droplets to the mitochondria based on multiple studies that identified SNAREs as components of cytoplasmic lipid droplets. We established and characterized an in vitro mitochondria reconstitution assay system that enabled us to examine the impact of adding recombinant SNARE proteins specifically on the movement of cholesterol from model lipid droplets to the outer mitochondrial membrane. Using this reconstitution assay system in combination with siRNA knockdown experiments in rat primary granulosa cells or in steroidogenic cell lines, we showed that several SNARE proteins are important components in the trafficking of cholesterol from lipid droplets to the mitochondria for steroidogenesis.



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A single cell level measurement of StAR expression and activity in adrenal cells

Publication date: 5 February 2017
Source:Molecular and Cellular Endocrinology, Volume 441
Author(s): Jinwoo Lee, Takeshi Yamazaki, Hui Dong, Colin Jefcoate
The Steroidogenic acute regulatory protein (StAR) directs mitochondrial cholesterol uptake through a C-terminal cholesterol binding domain (CBD) and a 62 amino acid N-terminal regulatory domain (NTD) that contains an import sequence and conserved sites for inner membrane metalloproteases. Deletion of the NTD prevents mitochondrial import while maintaining steroidogenesis but with compromised cholesterol homeostasis. The rapid StAR-mediated cholesterol transfer in adrenal cells depends on concerted mRNA translation, p37 StAR phosphorylation and controlled NTD cleavage. The NTD controls this process with two cAMP-inducible modulators of, respectively, transcription and translation SIK1 and TIS11b/Znf36l1. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA resolves slow RNA splicing at the gene loci in cAMP-induced Y-1 cells and transfer of individual 3.5 kB mRNA molecules to mitochondria. StAR transcription depends on the CREB coactivator CRTC2 and PKA inhibition of the highly inducible suppressor kinase SIK1 and a basal counterpart SIK2. PKA-inducible TIS11b/Znf36l1 binds specifically to highly conserved elements in exon 7 thereby suppressing formation of mRNA and subsequent translation. Co-expression of SIK1, Znf36l1 with 3.5 kB StAR mRNA may limit responses to pulsatile signaling by ACTH while regulating the transition to more prolonged stress.



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Receptor tyrosine kinase inhibition by regorafenib/sorafenib inhibits growth and invasion of meningioma cells

Publication date: March 2017
Source:European Journal of Cancer, Volume 73
Author(s): Marcus Tuchen, Annette Wilisch-Neumann, Evelyn A. Daniel, Lisa Baldauf, Doreen Pachow, Johannes Scholz, Frank Angenstein, Oliver Stork, Elmar Kirches, Christian Mawrin
Systemic chemotherapeutic treatment for unresectable and/or aggressive meningiomas is still unsatisfying. PDGF receptor (PDGFR)-mediated activation of mitogenic signalling has been shown to be active in meningiomas. Therefore, we evaluate in vitro and in vivo the effects of inhibiting PDGFR using the clinically well-characterised tyrosine kinase inhibitors sorafenib or regorafenib in meningioma models. IOMM-Lee meningioma cells were used to assess cytotoxic effects, inhibition of proliferation, induction of apoptosis, as well as inhibition of migration and motility by sorafenib and regorafenib. Using an orthotopic mouse xenograft model, growth inhibition as monitored by magnetic resonance imaging, and overall survival of sorafenib- or regorafenib-treated mice compared with control animals was determined. Treatment of malignant IOMM-Lee cells resulted in significantly reduced cell survival and induction of apoptosis following regorafenib and sorafenib treatment. Western blots showed that both drugs target phosphorylation of p44/42 ERK via downregulation of the PDGFR. Both drugs additionally showed significant inhibition of cell motility and invasion. In vivo, mice with orthotopic meningioma xenografts showed a reduced volume (n.s.) of signal enhancement in MRI (mainly tumour) following sorafenib and regorafenib treatment. This was translated in a significantly increased overall survival time (p ≤ 0.05) for regorafenib-treated mice. Analyses of in vivo-grown tumours demonstrated again reduced PDGFR expression and expression/phosphorylation of p44/42. Sorafenib and regorafenib show antitumour activity in vitro and in vivo by targeting PDGFR and p44/42 ERK signalling.



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Acquisition of Basic Microsurgery Skills Using Home Based Simulation Training – A Randomised Control Study

Acquisition of the fine motor skills required in microsurgery can be challenging in the current training system. As a result, there is an increased demand for novel training and assessment methods to optimise learning outside the clinical setting. We present a randomised control trial of three microsurgical training models – laboratory tabletop training microscope (Laboratory Microscope, LM), low-cost jewellers microscope (Home Microscope, HM) and iPad trainer (Home Tablet, HT).

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An analysis of the ideal muscle weight of gracilis muscle transplants for facial reanimation surgery with regard to the donor nerve and outcome

Free functional muscle transfers represent the "criterion standard" for smile reconstruction in facial paralysis. The gracilis muscle is a common donor muscle, however no data exist regarding volume of muscle tissue that is necessary for symmetric commissure excursion.

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Benign hand tumors are indicated for surgery, according to patient-rated outcome measures

This study assessed the treatment outcomes of upper extremity benign tumours using the patient-rated outcome measure Hand20 questionnaire.

http://ift.tt/2iXtYG1

Surgical treatment of disabling conditions caused by anogenital lichen sclerosus in women: an account of surgical procedures and results, including patient satisfaction, benefits and improvements in aspects of health-related quality of life

Anogenital lichen sclerosus (LS), a chronic dermatitis causing scarring and introital stenosis, may prevent sexual intercourse and reduce health-related quality of life (QoL). Surgery can restore the anatomy, allowing patients to resume their sexual lives. This study investigates outcomes in women treated with local skin flaps.

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Impact of the method and success of pharyngeal reconstruction on the outcome of treating laryngeal and hypopharyngeal cancers with pharyngolaryngectomy: a national analysis

Surgical treatment of cancers which arise from or invade the hypopharynx presents major reconstructive challenges. Reconstructive failure exposes the airway and neck vessels to digestive contents.

http://ift.tt/2iXGlC5

Cephalometric Changes Associated With Spring-Assisted Cranioplasty For Scaphocephaly – Analysis Of The Changes In The First Three-Months

Spring-assisted cranioplasty (SAC) has become an accepted treatment for patients with sagittal craniosynostosis, however, early effects of springs on skull dimensions have never been assessed with objective measurements in the literature. This study evaluated changes in skull dimensions and intracranial volume (ICV) during the first three months of SAC for sagittal synostosis.

http://ift.tt/2iWsJoD