Molecular analysis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Hong Kong Chinese patients

BackgroundCongenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder due to mutation in the CYP21A2 gene.ObjectiveTo elucidate the genetic basis of 21-hydroxylase-deficient CAH in Hong Kong Chinese patients.Patients and methodsMutational analysis of the CYP21A2 gene was performed on 35 Hong Kong Chinese patients with 21OHD using direct DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).ResultsThe genetic findings of 21 male and 14 female patients are the following: c.293-13A/C>G (intron 2 splice site; 20 alleles), p.I172N (13), p.R356W (7), p.Q318X (4). A total of 20 mutant alleles contained gross deletion/conversion of all or part of the CYP21A2 gene. A novel mutation, c.1367delA (p.D456fs), was detected in one patient. One patient had only a heterozygous mutation detected. Out of 35 patients, 16 would have been incorrectly genotyped if either DNA sequencing or MLPA alone was used for molecular analysis.ConclusionsThe frequency of various mutations in the studied patients differs from those reported in other Asian populations. Gross deletion/conversion accounts for nearly one-third of the genetic defects. Therefore, laboratories must include methods for detecting point mutations as well as gross deletions/conversions to avoid misinterpretation of genotype. Genotyping has increasingly been proven to be a useful tool for supplementing, if not replacing, hormonal profiling for the diagnosis of 21OHD.     

In situ hybridization and immunolocalization of concentrative and equilibrative nucleoside transporters in the human intestine, liver, kidneys, and placenta

To better understand the role of human equilibrative (hENTs) and concentrative (hCNTs) nucleoside transporters in physiology and pharmacology, we investigated the regional, cellular, and spatial distribution of two hCNTs (hCNT1 and hCNT2) and two hENTs (hENT1 and hENT2) in four human tissues. Using in situ hybridization and immunohistochemical techniques, we found that the duodenum expressed hCNT1 and hCNT2 mRNAs in enterocytes and hENT1 and hENT2 mRNAs in crypt cells. In these cells, the hCNT and hENT proteins were predominantly localized in the apical and lateral membrane, respectively. Hepatocytes expressed higher levels of mRNAs of hENT1, hCNT1, and hENT2 than of hCNT2 and expressed all these proteins at hepatocyte cell borders and in the cytoplasm. While the kidney expressed hCNT1 and hCNT2 mRNAs in the proximal tubules, hENT1 and hENT2 mRNAs were present in the distal tubules, glomeruli, endothelial cells, and vascular smooth muscle cells. Proximal tubules adjacent to corticomedullary junctions expressed hENT1, hCNT1, and hCNT2 mRNA. Immunolocalization studies revealed predominant localization of hCNTs in the brush-border membrane of the proximal tubular epithelial cells and hENTs in the basolateral membrane of the distal tubular epithelial cells. Chorionic villi sections of human term placenta expressed mRNAs and proteins for hENT1 and hENT2 but only mRNA for hCNT2. Immunolocalization studies showed presence of hENT1 in the brush-border membrane of the syncytiotrophoblasts. These data are critical for a better understanding of the role of nucleoside transporters in the physiological and pharmacological effects of nucleosides and nucleoside drugs, respectively.     

Functional ion channels in mouse bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (MSCs) are used as a cell source for cardiomyoplasty; however, the cellular electrophysiological properties are not fully understood. The present study was to investigate the functional ionic channels in undifferentiated mouse bone marrow MSCs using whole cell patch-voltage clamp technique, RT-PCR, and Western immunoblotting analysis. We found that three types of ionic currents were present in mouse MSCs, including a Ca²⁺-activated K⁺ current (I_KCa), an inwardly rectifying K⁺ current (I_Kir), and a chloride current (I_Cl). I_Kir was inhibited by Ba²⁺, and I_KCa was activated by the Ca²⁺ ionophore A-23187 and inhibited by the intermediate-conductance I_KCa channel blocker clotrimazole. I_Cl was activated by hyposmotic (0.8 T) conditions and inhibited by the chloride channel blockers DIDS and NPPB. The corresponding ion channel genes and proteins, KCa3.1 for I_KCa, Kir2.1 for I_Kir, and Clcn3 for I_Cl, were confirmed by RT-PCR and Western immunoblotting analysis in mouse MSCs. These results demonstrate that three types of functional ion channel currents (i.e., I_Kir, I_KCa, and I_Cl) are present in mouse bone marrow MSCs. inward rectifier potassium current; intermediate-conductance calcium-activated potassium current; volume-sensitive chloride current     

Monitoring program design for data‐limited marine biogenic habitats: A structured approach

Marine biogenic habitats—habitats created by living organisms—provide essential ecosystem functions and services, such as physical structuring, nutrient cycling, biodiversity support, and increases in primary, secondary, and tertiary production. With the growing trend toward ecosystem approaches to marine conservation and fisheries management, there is greater emphasis on rigorously designed habitat monitoring programs. However, such programs are challenging to design for data‐limited habitats for which underlying ecosystem processes are poorly understood. To provide guidance in this area, we reviewed approaches to benthic assessments across well‐studied marine biogenic habitats and identified common themes related to indicator selection, sampling methods, and survey design. Biogenic habitat monitoring efforts largely focus on the characteristics, distribution, and ecological function of foundation species, but may target other habitat‐forming organisms, especially when community shifts are observed or expected, as well as proxies of habitat status, such as indicator species. Broad‐scale methods cover large spatial areas and are typically used to examine the spatial configuration of habitats, whereas fine‐scale methods tend to be laborious and thus restricted to small survey areas, but provide high‐resolution data. Recent, emerging methods enhance the capabilities of surveying large areas at high spatial resolution and improve data processing efficiency, bridging the gap between broad‐ and fine‐scale methods. Although sampling design selection may be limited by habitat characteristics and available resources, it is critically important to ensure appropriate matching of ecological, observational, and analytical scales. Drawing on these common themes, we propose a structured, iterative approach to designing monitoring programs for marine biogenic habitats that allows for rigorous data collection to inform management strategies, even when data and resource limitations are present. A practical application of this approach is illustrated using glass sponge reefs—a recently discovered and data‐limited habitat type—as a case study.     

A Novel Activation Mechanism of Avian Influenza Virus H9N2 by Furin

Avian influenza virus H9N2 is prevalent in waterfowl and has become endemic in poultry in Asia and the Middle East. H9N2 influenza viruses have served as a reservoir of internal genes for other avian influenza viruses that infect humans, and several cases of human infection by H9N2 influenza viruses have indicated its pandemic potential. Fortunately, an extensive surveillance program enables close monitoring of H9N2 influenza viruses worldwide and has generated a large repository of virus sequences and phylogenetic information. Despite the large quantity of sequences in different databases, very little is known about specific virus isolates and their pathogenesis. Here, we characterize a low-pathogenicity avian influenza virus, A/chicken/Israel/810/2001 (H9N2) (Israel810), which is representative of influenza virus strains that have caused severe morbidity and mortality in poultry farms. We show that under certain circumstances the Israel810 hemagglutinin (HA) can be activated by furin, a hallmark of highly pathogenic avian influenza virus. We demonstrate that Israel810 HA can be cleaved in cells with high levels of furin expression and that a mutation that eliminates a glycosylation site in HA₁ allows the Israel810 HA to gain universal cleavage in cell culture. Pseudoparticles generated from Israel810 HA, or the glycosylation mutant, transduce cells efficiently. In contrast, introduction of a polybasic cleavage site into Israel810 HA leads to pseudoviruses that are compromised for transduction. Our data indicate a mechanism for an H9N2 evolutionary pathway that may allow it to gain virulence in a distinct manner from H5 and H7 influenza viruses.     

Subcutaneous Adipocytes Promote Melanoma Cell Growth by Activating the Akt Signaling Pathway: ROLE OF PALMITIC ACID*

Tumorigenesis involves constant communication between tumor cells and neighboring normal cells such as adipocytes. The canonical function of adipocytes is to store triglyceride and release fatty acids for other tissues. This study was aimed to find out if adipocytes promoted melanoma cell growth and to investigate the underlying mechanism. Here we isolated adipocytes from inguinal adipose tissue in mice and co-cultured with melanoma cells. We found that the co-cultured melanoma had higher lipid accumulation compared with mono-cultured melanoma. In addition, fluorescently labeled fatty acid BODIPY® FLC16 signal was detected in melanoma co-cultured with the adipocytes that had been loaded with the fluorescent dye, suggesting that the adipocytes provide fatty acids to melanoma cells. Compared with mono-cultured melanoma, co-cultured melanoma cells had a higher proliferation and phospho-Akt (Ser-473 and Thr-450) expression. Overexpression of Akt mutants in melanoma cells reduced the co-culture-enhanced proliferation. A lipidomic study showed that the co-cultured melanoma had an elevated palmitic acid level. Interestingly, we found that palmitic acid stimulated melanoma cell proliferation, changed the cell cycle distribution, and increased phospho-Akt (Ser-473 and Thr-450) and PI3K but not phospho-PTEN (phosphophosphatase and tensin homolog) expressions. More importantly, the palmitic acid-stimulated proliferation was further enhanced in the Akt-overexpressed melanoma cells and was reduced by {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 or knockdown of endogenous Akt or overexpression of Akt mutants. We also found that palmitic acid-pretreated B16F10 cells were grown to a significantly larger tumor in mice compared with control cells. Taken together, we suggest that adipocytes may serve as an exogenous source of palmitic acid that promotes melanoma cell growth by activating Akt.     

A turn‐on indole‐based sensor for hydrogen sulfate ion

A simple indole‐based receptor 1 was prepared by a simple Schiff‐base reaction of 1H‐indole‐3‐carbaldehyde with ethane 1,2‐diamine and its fluoroionophoric properties toward anions were investigated. Indole‐based receptor 1 acts as a selective turn‐on fluorescent sensor for HSO₄^? in methanol among a series of tested anions. Fluorescence spectroscopy, ultraviolet and nuclear magnetic resonance imaging support that the HSO₄^– indeed interacted with imine nitrogen and the proton of nitrogen in indole ring. Copyright © 2013 John Wiley & Sons, Ltd.     

The Neuromuscular Junction: Measuring Synapse Size,Fragmentation and Changes in Synaptic Protein Density Using Confocal Fluorescence Microscopy

The neuromuscular junction (NMJ) is the large, cholinergic relay synapse through which mammalian motor neurons control voluntary muscle contraction. Structural changes at the NMJ can result in neurotransmission failure, resulting in weakness, atrophy and even death of the muscle fiber. Many studies have investigated how genetic modifications or disease can alter the structure of the mouse NMJ. Unfortunately, it can be difficult to directly compare findings from these studies because they often employed different parameters and analytical methods. Three protocols are described here. The first uses maximum intensity projection confocal images to measure the area of acetylcholine receptor (AChR)-rich postsynaptic membrane domains at the endplate and the area of synaptic vesicle staining in the overlying presynaptic nerve terminal. The second protocol compares the relative intensities of immunostaining for synaptic proteins in the postsynaptic membrane. The third protocol uses Fluorescence Resonance Energy Transfer (FRET) to detect changes in the packing of postsynaptic AChRs at the endplate. The protocols have been developed and refined over a series of studies. Factors that influence the quality and consistency of results are discussed and normative data are provided for NMJs in healthy young adult mice.