Name: in vitro enzyme measurement to test pharmacological chaperone responsiveness in fabry and pompe disease
Uploaded: 2017-12-20T14:00:00
Description: Watch this Scientific Journal Video about In Vitro Enzyme Measurement to Test Pharmacological Chaperone Responsiveness in Fabry and Pompe Disease at JoVE.com

The authors would like to acknowledge Mandy Loebert and Tina Czajka for excellent technical support. We thank Flora Luo (Harvard Medical School, Boston, MA, USA) for language editing help.

1. Preparation of Mutant pcDNA3.1/GLA and pcDNA3.1/GAA Constructs
NOTE: The cloning strategies for the GLA and GAA coding sequences (cds) have been reported earlier15,18.
<ol>
	<li>Site-directed Mutagenesis Using Site-Directed Mutagenesis
	<ol>
		<li>Use the reference sequences NM_000169.2 and NM_000152.4 as templates for the mutagenesis of GLA and GAA genes, respectively. Have a s...

<ol>
	<li>Ishii, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutant+alpha-galactosidase+A+enzymes+identified+in+Fabry+disease+patients+with+residual+enzyme+activity:+biochemical+characterization+and+restoration+of+normal+intracellular+processing+by+1-deoxygalactonojirimycin.">Mutant alpha-galactosidase A enzymes identified in Fabry disease patients with residual enzyme activity: biochemical characterization and restoration of normal intracellular processing by 1-deoxygalactonojirimycin.</a> Biochem J. 406, 285-295 (2007).</li><li>Tajima, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+biochemical+studies+on+Pompe+disease+and+a+&amp;#34;pseudodeficiency+of+acid+alpha-glucosidase&amp;#34.">Structural and biochemical studies on Pompe disease and a &amp;#34;pseudodeficiency of acid alpha-glucosidase&amp;#34.</a> J Hum Genet. 52, 898-906 (2007).</li><li>Lukas, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+Clinical+Consequences+of+Novel+&#945;-Galactosidase+A+Mutations+in+Fabry+Disease.">Functional and Clinical Consequences of Novel &#945;-Galactosidase A Mutations in Fabry Disease.</a> Hum Mutat. 37, 43-51 (2016).</li><li>Parenti, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treating+lysosomal+storage+diseases+with+pharmacological+chaperones:+from+concept+to+clinics.">Treating lysosomal storage diseases with pharmacological chaperones: from concept to clinics.</a> EMBO Mol Med. 1, 268-279 (2009).</li><li>Yasuda, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabry+disease:+characterization+of+alpha-galactosidase+A+double+mutations+and+the+D313Y+plasma+enzyme+pseudodeficiency+allele.">Fabry disease: characterization of alpha-galactosidase A double mutations and the D313Y plasma enzyme pseudodeficiency allele.</a> Hum Mutat. 22, 486-492 (2003).</li><li>Shimotori, M., Maruyama, H., Nakamura, G., Suyama, T., Sakamoto, F., Itoh, M., Miyabayashi, S., Ohnishi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+mutations+of+the+GLA+gene+in+Japanese+patients+with+Fabry+disease+and+their+functional+characterization+by+active+site+specific+chaperone.">Novel mutations of the GLA gene in Japanese patients with Fabry disease and their functional characterization by active site specific chaperone.</a> Hum Mutat. 29, 331 (2008).</li><li>Andreotti, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Therapy+of+Fabry+disease+with+pharmacological+chaperones:+from+in+silico+predictions+to+in+vitro+tests.">Therapy of Fabry disease with pharmacological chaperones: from in silico predictions to in vitro tests.</a> Orphanet J Rare Dis. 6, 66 (2011).</li><li>Khanna, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pharmacological+chaperone+AT2220+increases+the+specific+activity+and+lysosomal+delivery+of+mutant+acid+alpha-glucosidase,+and+promotes+glycogen+reduction+in+a+transgenic+mouse+model+of+Pompe+disease.">The pharmacological chaperone AT2220 increases the specific activity and lysosomal delivery of mutant acid alpha-glucosidase, and promotes glycogen reduction in a transgenic mouse model of Pompe disease.</a> PLoS One. 9, e102092 (2014).</li><li>Siekierska, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#945;-Galactosidase+aggregation+is+a+determinant+of+pharmacological+chaperone+efficacy+on+Fabry+disease+mutants.">&#945;-Galactosidase aggregation is a determinant of pharmacological chaperone efficacy on Fabry disease mutants.</a> J Biol Chem. 287, 28386-28397 (2012).</li><li>Parenti, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+enhancement+of+mutated+alpha-glucosidase+activity+in+fibroblasts+from+patients+with+Pompe+disease.">Pharmacological enhancement of mutated alpha-glucosidase activity in fibroblasts from patients with Pompe disease.</a> Mol Ther. 15, 508-514 (2007).</li><li>Wu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+pharmacogenetic+approach+to+identify+mutant+forms+of+&#945;-galactosidase+A+that+respond+to+a+pharmacological+chaperone+for+Fabry+disease.">A pharmacogenetic approach to identify mutant forms of &#945;-galactosidase A that respond to a pharmacological chaperone for Fabry disease.</a> Hum Mutat. 32, 965-977 (2011).</li><li>Lukas, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+characterisation+of+alpha-galactosidase+a+mutations+as+a+basis+for+a+new+classification+system+in+fabry+disease.">Functional characterisation of alpha-galactosidase a mutations as a basis for a new classification system in fabry disease.</a> PLoS Genet. 9, e1003632 (2013).</li><li>Andreotti, G., Citro, V., Correra, A., Cubellis, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+thermodynamic+assay+to+test+pharmacological+chaperones+for+Fabry+disease.">A thermodynamic assay to test pharmacological chaperones for Fabry disease.</a> Biochim Biophys Acta. 1840, 1214-1224 (2014).</li><li>. Available from: <a target="_blank" href="https://www.google.ch/patents/US9095584">https://www.google.ch/patents/US9095584</a> (2017)</li><li>Lukas, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enzyme+enhancers+for+the+treatment+of+Fabry+and+Pompe+disease.">Enzyme enhancers for the treatment of Fabry and Pompe disease.</a> Mol Ther. 23, 456-4564 (2015).</li><li>Yam, G. H., Bosshard, N., Zuber, C., Steinmann, B., Roth, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+chaperone+corrects+lysosomal+storage+in+Fabry+disease+caused+by+trafficking-incompetent+variants.">Pharmacological chaperone corrects lysosomal storage in Fabry disease caused by trafficking-incompetent variants.</a> Am J Physiol Cell Physiol. 290, C1076-C1082 (2006).</li><li>Shin, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screening+for+pharmacological+chaperones+in+Fabry+disease.">Screening for pharmacological chaperones in Fabry disease.</a> Biochem Biophys Res Commun. 359, 168-173 (2007).</li><li>Shin, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prediction+of+response+of+mutated+alpha-galactosidase+A+to+a+pharmacological+chaperone.">Prediction of response of mutated alpha-galactosidase A to a pharmacological chaperone.</a> Pharmacogenet Genomics. 18, 773-7780 (2008).</li><li>Filoni, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+studies+of+new+GLA+gene+mutations+leading+to+conformational+Fabry+disease.">Functional studies of new GLA gene mutations leading to conformational Fabry disease.</a> Biochim Biophys Acta. 1802, 247-252 (2010).</li><li>Citro, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Large+Phenotypic+Spectrum+of+Fabry+Disease+Requires+Graduated+Diagnosis+and+Personalized+Therapy:+A+Meta-Analysis+Can+Help+to+Differentiate+Missense+Mutations.">The Large Phenotypic Spectrum of Fabry Disease Requires Graduated Diagnosis and Personalized Therapy: A Meta-Analysis Can Help to Differentiate Missense Mutations.</a> Int J Mol Sci. 17, (2016).</li><li>Cammisa, M., Correra, A., Andreotti, G., Cubellis, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabry_CEP:+a+tool+to+identify+Fabry+mutations+responsive+to+pharmacological+chaperones.">Fabry_CEP: a tool to identify Fabry mutations responsive to pharmacological chaperones.</a> Orphanet J Rare Dis. 8, 111 (2013).</li><li>Leinekugel, P., Michel, S., Conzelmann, E., Sandhoff, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+correlation+between+the+residual+activity+of+beta-hexosaminidase+A+and+arylsulfatase+A+and+the+severity+of+the+resulting+lysosomal+storage+disease.">Quantitative correlation between the residual activity of beta-hexosaminidase A and arylsulfatase A and the severity of the resulting lysosomal storage disease.</a> Hum Genet. 88, 513-523 (1992).</li><li>Germain, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safety+and+pharmacodynamic+effects+of+a+pharmacological+chaperone+on+&#945;-galactosidase+A+activity+and+globotriaosylceramide+clearance+in+Fabry+disease:+report+from+two+phase+2+clinical+studies.">Safety and pharmacodynamic effects of a pharmacological chaperone on &#945;-galactosidase A activity and globotriaosylceramide clearance in Fabry disease: report from two phase 2 clinical studies.</a> Orphanet J Rare Dis. 7, 91 (2012).</li><li>Hughes, D. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+pharmacological+chaperone+migalastat+compared+with+enzyme+replacement+therapy+in+Fabry+disease:+18-month+results+from+the+randomised+phase+III+ATTRACT+study.">Oral pharmacological chaperone migalastat compared with enzyme replacement therapy in Fabry disease: 18-month results from the randomised phase III ATTRACT study.</a> J Med Genet. 54, 288-296 (2017).</li><li>Parenti, G., Andria, G., Valenzano, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+Chaperone+Therapy:+Preclinical+Development,+Clinical+Translation,+and+Prospects+for+the+Treatment+of+Lysosomal+Storage+Disorders.">Pharmacological Chaperone Therapy: Preclinical Development, Clinical Translation, and Prospects for the Treatment of Lysosomal Storage Disorders.</a> Mol Ther. 23, 1138-1148 (2015).</li><li>Parenti, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Chaperone+Enhances+Blood+&#945;-Glucosidase+Activity+in+Pompe+Disease+Patients+Treated+With+Enzyme+Replacement+Therapy.">A Chaperone Enhances Blood &#945;-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy.</a> Mol Ther. 22, 2004-2012 (2014).</li></ol>

The protocol described herein delivers robust results for enzyme damage assessment in hereditary lysosomal diseases of metabolism. This manuscript is an amendment to the protocol published earlier15. The most crucial modifications involve stringency (i.e., in the process of mutant vector construct preparation), standardization of the cell culture protocol (i.e., HEK293H cell maintenance and transfection conditions), and the high number of experimental repetitions (at least 5), wh...

There are over a dozen lysosomal storage disorders (LSDs) related to glycosidase dysfunction as a result of primary gene mutations. In Fabry (OMIM #301500) and Pompe (OMIM #232300) disease, more than 500 and 200 missense mutations1,2,3 have been reported, respectively, which corresponds to about 60% of the total mutation count. Numerous new gene variants are still being identified, many of which have unknown significance. Extensive biochemical studies revealed that certain genotypes do not lead to a complete loss-of-function of the GLA gene (OMIM *300644) in Fabry disease, but cause the corresponding enzyme to fail to reach a thermodynamically favored folding state4. This results in ER retention and premature degradation of the otherwise functional enzyme. Similar conclusions have been drawn in other LSDs including Pompe disease5. Moreover, molecular characterization of enzyme variants can facilitate clinical interpretation of the mutations at the time of diagnosis6, suggesting that LSD progression is an individual process based on the nature of the mutation. Therefore, the conventional classification into typically 2 to 3 different clinical types should be reassessed in order to streamline clinical counselling and therapeutic decisions.
Enzyme Replacement Therapy (ERT) is available for both diseases. ERT, however, has limited efficacy in affected tissues/organs such as the brain and skeletal muscle. Furthermore, ERT can elicit an immunogenic response that jeopardizes its therapeutic benefits. Pharmacological Chaperones (PCs) are an attractive treatment alternative for patients with so-called responsive mutations. PCs serve as a molecular scaffold for correct protein folding and stabilization which in turn prevents endoplasmic reticulum (ER) retention and ER-associated degradation of the enzyme. Moreover, PCs can be administered orally and are potentially able to cross the blood brain barrier. Therefore, PCT might be a more viable option for treating patients with certain genotypes. For an extensive review on PC application in LSDs, refer to the excellent review by Parenti7.
The discovery of hundreds of disease causing mutant alleles challenges pre-clinical drug testing and necessitates a simple, fast, and highly standardized assessment of amenable patients for a personalized medicine approach. In order to assess the detrimental effects of LSD gene mutations and to test candidate mutations to predict amenable patients for PCT, a highly standardized over-expression system in HEK293H cells that allows for fast and reliable enzyme activity measurement was developed. Similar over-expression systems have been previously described for Fabry and Pompe disease using either COS-78,9,10,11, HeLa cells12, or HEK29313,14,15,16 cells for the glycosidase gene.
A very similar method has even been patented as a &#34;Method to predict response to Pharmacological Chaperone treatment of diseases&#34;17 indicating the relevance of a cell culture system capable of being integrated into clinical practice.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Material</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>QuikChange II XL Site-Directed Mutagenesis Kit&#160;</td>
			<td>Stratagene, La Jolla, CA, USA</td>
			<td>#200522</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[R301Q]-frw: 5&#180;- CTA ATG ACC TCC AAC ACA TCA GCC C-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[R301Q]-rev: 5&#180;- GGG CTG ATG TGT TGG AGG TCA TTA G-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[A156V]-frw: 5&#180;-CTA CGA CAT TGA TGT CCA GAC CTT TGC TG-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[A156V]-rev: 5&#180;-CAG CAA AGG TCT GGA CAT CAA TGT CGT AG-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[A156V]-frw: 5&#180;-GGA AAT AAA ACC TGC ACA GGC TTC CCT GGG A-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GLA[A143T]-rev: 5&#180;-TCC CAG GGA AGC CTG TGC AGG TTT TAT TTC C-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[F455Y]-frw: 5&#180;-CTG CCG GGA GCT TCA GGC CCT ACG A-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[F455Y]-rev: 5&#180;-TCG TAG GGC CTG AAG CTC CCG GCA G-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[P545L]-frw: 5&#180;-CAC CCT ACG TGC TTG GGG TGG TTG G-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[P545L]-rev: 5&#180;-CCA ACC ACC CCA AGC ACG TAG GGT G-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[L552P]-frw: 5&#180;-TTG GGG GGA CCC CCC AGG CGG CCA C-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer GAA[P545L]-rev: 5&#180;-GTG GCC GCC TGG GGG GTC CCC CCA A-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer T7: 5&#180;-TAA TAC GAC TCA CTA TAG GG-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Primer BGHrev: 5&#180;-TAG AAG GCA CAG TCG AGG-3&#180;</td>
			<td>MWG Eurofins Operon, Ebersberg, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>8952.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Yeast Extract</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>103,753</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,064,041,000</td>
			<td></td>
		</tr>
		<tr>
			<td>Potasium chloride</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,049,360,500</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2 x 6H2O</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,058,330,250</td>
			<td></td>
		</tr>
		<tr>
			<td>D (+)-Glucose monohydrate</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,083,422,500</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Hydroxide</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,064,980,500</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>3908.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Citric acid</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>X863.3</td>
			<td></td>
		</tr>
		<tr>
			<td>disodium hydrogen phosphate</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,065,860,500</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium acetate</td>
			<td>Merck, Darmstadt, Germany</td>
			<td>1,062,640,050</td>
			<td></td>
		</tr>
		<tr>
			<td>Glacial acetic acid</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>A6283</td>
			<td></td>
		</tr>
		<tr>
			<td>LB Agar</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>X969.2</td>
			<td></td>
		</tr>
		<tr>
			<td>LB Medium</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>X968.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Zyppy Plasmid Miniprep Kit</td>
			<td>ZymoResearch, Freiburg, Germany</td>
			<td>D4020</td>
			<td></td>
		</tr>
		<tr>
			<td>QIAfilter Plasmid Midi Kit</td>
			<td>Qiagen, Hilden, Germany</td>
			<td>12245</td>
			<td></td>
		</tr>
		<tr>
			<td>HEK293H cell line</td>
			<td>Invitrogen, Karlsruhe, Germany</td>
			<td>11631-017&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#180;s Modified Eagle Medium&#160;</td>
			<td>Invitrogen, Karlsruhe, Germany</td>
			<td>31966-047</td>
			<td></td>
		</tr>
		<tr>
			<td>HyClone fetal bovine serum&#160;</td>
			<td>GE Healthcare, South Logan, Utah, USA</td>
			<td>SV30160.03</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Invitrogen, Karlsruhe, Germany</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>CELLSTAR Standard Cell Culture Flasks, Greiner Bio One</td>
			<td>VWR International GmbH, Hannover, Germany</td>
			<td>82050-854</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plates (24 well)</td>
			<td>Sarstedt, N&#252;mbrecht, Germany</td>
			<td>831,836</td>
			<td></td>
		</tr>
		<tr>
			<td>Cellstar 96 well plate</td>
			<td>Greiner bio one, Frickenhausen, Germany</td>
			<td>655185</td>
			<td></td>
		</tr>
		<tr>
			<td>SafeSeal reaction tubes, 1,5mL&#160;</td>
			<td>Sarstedt, N&#252;mbrecht, Germany</td>
			<td>72,706</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipofectamine 2000</td>
			<td>Invitrogen, Karlsruhe, Germany</td>
			<td>11668-019</td>
			<td></td>
		</tr>
		<tr>
			<td>1-Deoxygalactonojirimycin Hydrochloride&#160;</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>D9641</td>
			<td></td>
		</tr>
		<tr>
			<td>1-Deoxygalactonojirimycin Hydrochloride&#160;</td>
			<td>Toronto Research Chemicals, Toronto, Canada</td>
			<td>D236500</td>
			<td></td>
		</tr>
		<tr>
			<td>1-Deoxynojirimycin&#160;</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>D9305</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS Dulbecco w/o Calcium, w/o Magnesium</td>
			<td>Biochrom, Berlin, Germany</td>
			<td>L 1825</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.05%), phenol red</td>
			<td>Thermo Scientific, Braunschweig, Germany</td>
			<td>25300054</td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce BCA Protein Assay Kit</td>
			<td>Thermo Scientific, Braunschweig, Germany</td>
			<td>23225</td>
			<td></td>
		</tr>
		<tr>
			<td>4-Methylumbelliferone</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>M1381</td>
			<td></td>
		</tr>
		<tr>
			<td>4-Methylumbelliferyl &#945;-D-galactopyranoside</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>M7633</td>
			<td></td>
		</tr>
		<tr>
			<td>4-Methylumbelliferyl &#945;-D-glucopyranoside</td>
			<td>Sigma Aldrich, Munich, Germany</td>
			<td>M9766</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>incubator type T6</td>
			<td>Heraeus Instruments, Hanau, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Luminous Plate Gr. 2 E</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>P265.1</td>
			<td></td>
		</tr>
		<tr>
			<td>3130 xl Genetic Analyzer&#160;</td>
			<td>Applied Biosystems, Darmstadt, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>GFL-3032 bacterial shaker</td>
			<td>GFL, Burgwedel, Germany&#160;</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Avanti J-25 centrifuge</td>
			<td>Beckman/Coulter, Krefeld, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Ultraspec 3100 pro Spectrophotometer</td>
			<td>Amersham Biosciences, Buckinghamshire, United Kingdom</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>water-jacket incubator&#160;</td>
			<td>Binder, Tuttlingen, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex Genie 1 touch mixer</td>
			<td>Scientific Industries, Bohemia, NY, USA</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Z 233 MK-2 refrigerated microtube centrifuge</td>
			<td>Hermle, Tuttlingen, Germany&#160;</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>LaboStar ultrapure water device</td>
			<td>Siemens, Berlin, Germany</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermo Shaker PST-60HL-4 orbital shaker</td>
			<td>Biosan, Riga, Latvia</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Tecan GENios Reader</td>
			<td>Tecan, M&#228;nnedorf, Switzerland</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>HI 223 Microprocessor pH Meter</td>
			<td>HANNA Instruments, Arvore, Portugal</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>CASY 
			Cell Counter + Analyser System 
			Model TT</td>
			<td>Innovatis AG, Cham/Zug, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Software</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magellan data analysis software v6.6</td>
			<td>Tecan, M&#228;nnedorf, Switzerland</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>GraphPad Prism 5.04</td>
			<td>GraphPad Software, Inc., La Jolla, CA; USA</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Microsoft Office 2010</td>
			<td>Microsoft Corporation, Redmond, WA, USA</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>BioEdit Alignment Editor, V7.0.1</td>
			<td>http://www.mbio.ncsu.edu/bioedit/bioedit.html</td>
			<td>n.a.</td>
			<td></td>
		</tr>
		<tr>
			<td>Abbreviations</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>frw = forward; rev = reverse</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>n.a. = not applicable</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

in vitro enzyme measurement to test pharmacological chaperone responsiveness in fabry and pompe disease

The use of personalized medicine to treat rare monogenic diseases like lysosomal storage disorders (LSDs) is challenged by complex clinical trial designs, high costs, and low patient numbers. Hundreds of mutant alleles are implicated in most of the LSDs. The diseases are typically classified into 2 to 3 different clinical types according to severity. Moreover, molecular characterization of the genotype can help predict clinical outcomes and inform patient care. Therefore, we developed a simple cell culture assay based on HEK293H cells heterologously over-expressing the mutations identified in Fabry and Pompe disease. A similar assay has recently been introduced as a preclinical test to identify amenable mutations for Pharmacological Chaperone Therapy (PCT) in Fabry disease. This manuscript describes an amended cell culture assay which enables rapid phenotypic assessment of allelic variants in Fabry and Pompe disease to identify eligible patients for PCT and may aid in the development of novel pharmacochaperones.

The mutagenesis procedure 
To assess the efficiency of GLA gene mutagenesis, the mutations were classified into one of the following categories. This approach to generate mutations revealed that about 66.5% of the GLA mutations were obtained in the first attempt. A further 25% could be obtained after a slightly modified second PCR.
Category 1: The mutagenesis PCR was effective at first att...

Watch this Scientific Journal Video about In Vitro Enzyme Measurement to Test Pharmacological Chaperone Responsiveness in Fabry and Pompe Disease at JoVE.com

In Vitro Enzyme Measurement to Test Pharmacological Chaperone Responsiveness in Fabry and Pompe Disease

There is a demand to make pre-clinical testing for a novel class of "orphan" drugs called pharmacological chaperones reproducible, fast, and efficient. We developed a simple, highly standardized, and versatile cell culture-based assay to screen for eligible patients as well as novel pharmacological chaperone drugs.

In Vitro Enzyme Measurement to Test Pharmacological Chaperone Responsiveness in Fabry and Pompe Disease

The use of personalized medicine to treat rare monogenic diseases like lysosomal storage disorders (LSDs) is challenged by complex clinical trial designs, ...

The overall goal of this amended cell culture protocol is to supply a rapid phenotypic assessment of allelic variance in Fabry and Pompe disease. This method can help to answer key questions in the field of lysosomal storage diseases, such as prognostic outcomes and therapeutic decisions. The main advantage of this technique is that it is highly reproducible and that it can aid in the development of novel drugs, such as pharmaco-chaperones.To carry out site-directed mutagenesis, begin by using the reference sequences NM 00169.2 and NM 00152.4 as templates for the mutagenesis of GLA and GAA genes, respectively. Use the free Primer Design tool to support primer design. Then, have a set of high-purity, salt-free primers synthesized by a commercial provider, with sense and antisense primers carrying one of the respective sequence modifications, central to their length, to individually introduce the mutation.Prepare the reaction mixture in a 50 microliter volume and run the PCR program using standard conditions provided by the manufacturer and as listed in the text protocol. Following PCR, add one microliter of Dpn1 restriction enzyme and continue to incubate the reaction vials at 37 degrees Celsius for one hour. After transforming the plasma DNA into competent E.coli cells and preparing plasmids of the desired transformance according to the text protocol, use a suitable molecular biology tool to analyze the sequence.When the desired mutation is detected and no further sequence abnormality compared to NM 000169.2 for alpha-galactosidase A or NM 000152.4 for acid alpha-galactosidase is seen, select the clone for transfection-grade plasmid purification. Determine the purity of the DNA by measuring the absorbance in a spectrophotometer. Following the cultivation of HEK293H cells in a T75 culture flask according to the text protocol, 24 hours prior to the transfection, use PBS without calcium or magnesium to wash the cells once.With 0.05%Trypsin-EDTA, harvest the cells and in the cavities of a 24-well culture plate use 500 microliters of DMEM supplemented with 10%FBS to seed 1.5 times 10 to the five cells. Carry out cell transfection according to the manufacturer's manual. Using a mixture of one microgram of plasmid DNA dissolved in 100 microliters of serum-free DMEM and 2.5 microliters of transfection reagent.Incubate the solution for 20 minutes at room temperature, then add it to the cells in a dropwise manner. After a period of four hours at 37 degrees Celsius and 5%CO2, remove the medium containing the transfection reagent and add 500 microliters of fresh DMEM with 10%FBS and 1%penicillin-streptomycin. As an option during this step, add DGJ or DNJ to the culture medium where intended.On the day of the harvest, remove the cells from the incubator. Then aspirate the medium and use PBS with calcium and magnesium to carefully wash the cells two times. This step is critical because DGJ and DNJ are inhibitors of both enzymes, and therefore any left over would invalidate the test.Following the wash, add 200 microliters of deionized water directly on top of the cells. Then rinse the cells from the plate and transfer them to a 1.5 milliliter reaction tube. Place the samples in an appropriate foam rack and vortex them for five seconds to make the lysis more efficient.Then alternate the samples between liquid nitrogen for 10 seconds and a room-temperature water bath until the thawing is complete. After repeating the homogenization procedure five times, spin the samples for five minutes at 10, 000g. Then transfer the supernatant into a new reaction tube.To carry out the BCA assay, prepare a fresh tube for each sample containing 40 microliters of deionized H20 and add 10 microliters of sample. Mix each solution by briefly vortexing and transfer 10 microliters of each sample in triplicate into the cavities of a 96-well plate. To prepare a standard curve, dilute a 2 milligram per milliliter BSA stock solution and deionized H2O according to the text protocol.After combining reagent A and reagent B, start the reaction by adding 200 microliters of the BCA reagent solution and incubate the samples in the dark at 37 degrees Celsius and 300 rpm on an orbital shaker for one hour. Then measure the absorbance at 560 nanometers in a plate reader. The samples typically contain between one and 1.5 micrograms of protein per microliter.Dilute the calculated amount of each sample and pipette it into fresh 1.5 milliliter reaction tubes to obtain 0.05 micrograms of alpha-galactosidase A or 0.5 micrograms of acid alpha-glucosidase per microliter of solution. Vortex the samples for five seconds again and pipette 10 microliters of this dilution in duplicate into a 96-well plate. Start the reactions by adding 20 microliters of the respective substrate solution.For alpha-galactosidase A, add two millimolar 4-methylumbelliferyl alpha-D galactopyranoside, or 4-MU-gal, in 0.06 molar phosphate-citrate buffer, pH 4.7. For acid alpha-glucosidase, add 2 millimolar 4-methylumbelliferyl alpha-D glucopyranoside, or 4-MU-glu, in 0.025 molar sodium acetate, pH 4.0. Incubate the enzyme reactions for one hour in the dark at 37 degrees Celsius and 300 rpm on an orbital shaker.Then terminate the reaction by adding 200 microliters of 1.0 molar pH 10.5-adjusted glycine sodium-hydroxide buffer. Prepare a standard curve of 4-MU from a 0.01 milligram per milliliter stock according to the text protocol and pipette 10 microliters of the solutions in duplicate into a 96-well plate. Add 200 microliters of the 1.0 molar glycine sodium-hydroxide buffer to each well in order to adjust the volume and pH.Finally, measure the enzyme activity in a florescence reader equipped with the appropriate filter set. And analyze the data using the appropriate software for the fluorescence-reader device. To assess the efficiency of GLA gene mutagenesis, the mutations were classified into three categories and revealed that about 66.5%were obtained in the first attempt.A further 25%could be obtained after a slightly modified second PCR. In category three, more effort, such as primer redesign, had to be undertaken to yield the desired clone. This table refers to the enzyme-activity measurement results for three alpha-galactosidase A and three acid alpha-glucosidase mutations either left untreated or treated with DGJ and DNJ.The data are displayed as absolute values for the substrate turnover and has relative values normalized to the wild-type enzyme. The absolute enzyme activity data was corrected for endogenous enzyme activity of the HEK293H cells using cells transfected with an empty pcDNA 3.1 vector. Enzyme activity values were normalized to wild-type enzyme from corresponding experiments, which explains the deviation of relative values between the different mutants.Once mastered, the post-cell culture fraction of this experiment, which represents most of the hands-on time, can be done within four hours. After its development, this technique paved the way for researchers in the field of lysosomal storage diseases to explore genotype-phenotype correlations in Fabry and Pompe disease. This protocol can aid in the development of novel drugs in lysosomal storage diseases.

in-vitro-enzyme-measurement-to-test-pharmacological-chaperone

Research

JoVE Journal

Medicine

Making Sense of Listening: The IMAP Test Battery

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the abilities to extract and use the information encoded in the auditory signal. We refer to these as listening skills (or auditory processing AP). Deficits in these skills are associated with delayed language and literacy development, though the nature of the relevant deficits and their causal connection with these delays is hotly debated.
When a child is referred to a health professional with normal hearing and unexplained difficulties in listening, or associated delays in language or literacy development, they should ideally be assessed with a combination of psychoacoustic (AP) tests, suitable for children and for use in a clinic, together with cognitive tests to measure attention, working memory, IQ, and language skills. Such a detailed examination needs to be relatively short and within the technical capability of any suitably qualified professional. Current tests for the presence of AP deficits tend to be poorly constructed and inadequately validated within the normal population. They have little or no reference to the presenting symptoms of the child, and typically include a linguistic component. Poor performance may thus reflect problems with language rather than with AP. To assist in the assessment of children with listening difficulties, pediatric audiologists need a single, standardized child-appropriate test battery based on the use of language-free stimuli.
We present the IMAP test battery which was developed at the MRC Institute of Hearing Research to supplement tests currently used to investigate cases of suspected AP deficits. IMAP assesses a range of relevant auditory and cognitive skills and takes about one hour to complete. It has been standardized in 1500 normally-hearing children from across the UK, aged 6-11 years. Since its development, it has been successfully used in a number of large scale studies both in the UK and the USA. IMAP provides measures for separating out sensory from cognitive contributions to hearing. It further limits confounds due to procedural effects by presenting tests in a child-friendly game-format. Stimulus-generation, management of test protocols and control of test presentation is mediated by the IHR-STAR software platform. This provides a standardized methodology for a range of applications and ensures replicable procedures across testers. IHR-STAR provides a flexible, user-programmable environment that currently has additional applications for hearing screening, mapping cochlear implant electrodes, and academic research or teaching.

A test battery (IMAP) for performing an in-depth assessment of auditory and cognitive abilities contributing to listening skills is described. It is quick to administer, child-friendly and free from linguistic confounds. Stimulus generation and protocol management are controlled via a software platform (IHR-STAR) to ensure replicable procedures.

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the ...

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, the de novo mutation rate in humans is relatively high, so new mutations are generated at a high frequency in the population. However, de novo mutations have not been reported in most common diseases. Mutations in genes leading to severe diseases where there is a strong negative selection against the phenotype, such as lethality in embryonic stages or reduced reproductive fitness, will not be transmitted to multiple family members, and therefore will not be detected by linkage gene mapping or association studies. The observation of very high concordance in monozygotic twins and very low concordance in dizygotic twins also strongly supports the hypothesis that a significant fraction of cases may result from new mutations. Such is the case for diseases such as autism and schizophrenia. Second, despite reduced reproductive fitness1 and extremely variable environmental factors, the incidence of some diseases is maintained worldwide at a relatively high and constant rate. This is the case for autism and schizophrenia, with an incidence of approximately 1% worldwide. Mutational load can be thought of as a balance between selection for or against a deleterious mutation and its production by de novo mutation. Lower rates of reproduction constitute a negative selection factor that should reduce the number of mutant alleles in the population, ultimately leading to decreased disease prevalence. These selective pressures tend to be of different intensity in different environments. Nonetheless, these severe mental disorders have been maintained at a constant relatively high prevalence in the worldwide population across a wide range of cultures and countries despite a strong negative selection against them2. This is not what one would predict in diseases with reduced reproductive fitness, unless there was a high new mutation rate. Finally, the effects of paternal age: there is a significantly increased risk of the disease with increasing paternal age, which could result from the age related increase in paternal de novo mutations. This is the case for autism and schizophrenia3. The male-to-female ratio of mutation rate is estimated at about 4&#x2013;6:1, presumably due to a higher number of germ-cell divisions with age in males. Therefore, one would predict that de novo mutations would more frequently come from males, particularly older males4. A high rate of new mutations may in part explain why genetic studies have so far failed to identify many genes predisposing to complexes diseases genes, such as autism and schizophrenia, and why diseases have been identified for a mere 3% of genes in the human genome. Identification for de novo mutations as a cause of a disease requires a targeted molecular approach, which includes studying parents and affected subjects. The process for determining if the genetic basis of a disease may result in part from de novo mutations and the molecular approach to establish this link will be illustrated, using autism and schizophrenia as examples.

Molecular genetic strategy for finding de novo mutations causing common disorders such as autism and schizophrenia.

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, ...

The Measurement and Treatment of Suppression in Amblyopia

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current estimates put the prevalence of amblyopia at approximately 1-3%1-3, the majority of cases being monocular2. Amblyopia is most frequently caused by ocular misalignment (strabismus), blur induced by unequal refractive error (anisometropia), and in some cases by form deprivation.
Although amblyopia is initially caused by abnormal visual input in infancy, once established, the visual deficit often remains when normal visual input has been restored using surgery and/or refractive correction. This is because amblyopia is the result of abnormal visual cortex development rather than a problem with the amblyopic eye itself4,5 . Amblyopia is characterized by both monocular and binocular deficits6,7 which include impaired visual acuity and poor or absent stereopsis respectively. The visual dysfunction in amblyopia is often associated with a strong suppression of the inputs from the amblyopic eye under binocular viewing conditions8. Recent work has indicated that suppression may play a central role in both the monocular and binocular deficits associated with amblyopia9,10 .
Current clinical tests for suppression tend to verify the presence or absence of suppression rather than giving a quantitative measurement of the degree of suppression. Here we describe a technique for measuring amblyopic suppression with a compact, portable device11,12 . The device consists of a laptop computer connected to a pair of virtual reality goggles. The novelty of the technique lies in the way we present visual stimuli to measure suppression. Stimuli are shown to the amblyopic eye at high contrast while the contrast of the stimuli shown to the non-amblyopic eye are varied. Patients perform a simple signal/noise task that allows for a precise measurement of the strength of excitatory binocular interactions. The contrast offset at which neither eye has a performance advantage is a measure of the "balance point" and is a direct measure of suppression. This technique has been validated psychophysically both in control13,14 and patient6,9,11 populations.
In addition to measuring suppression this technique also forms the basis of a novel form of treatment to decrease suppression over time and improve binocular and often monocular function in adult patients with amblyopia12,15,16 . This new treatment approach can be deployed either on the goggle system described above or on a specially modified iPod touch device15.

Amblyopia is a developmental disorder of the visual cortex that is often accompanied by strong suppression of one eye. We present a new technique for measuring and treating interocular suppression in patients with amblyopia that can be deployed using virtual reality goggles or a portable iPod Touch device.

Amblyopia, a developmental disorder of the visual cortex, is one of the leading causes of visual dysfunction in the working age population. Current ...

A Simple Method of Mouse Lung Intubation

A simple procedure to intubate mice for pulmonary function measurements would have several advantages in longitudinal studies with limited numbers or expensive animal. One of the reasons that this is not done more routinely is that it is relatively difficult, despite there being several published studies that describe ways to achieve it. In this paper we demonstrate a procedure that eliminates one of the major hurdles associated with this intubation, that of visualizing the trachea during the entire time of intubation. The approach uses a 0.5 mm fiberoptic light source that serves as an introducer to direct the intubation cannula into the mouse trachea. We show that it is possible to use this procedure to measure lung mechanics in individual mice over a time course of at least several weeks. The technique can be set up with relatively little expense and expertise, and it can be routinely accomplished with relatively little training. This should make it possible for any laboratory to routinely carry out this intubation, thereby allowing longitudinal studies in individual mice, thereby minimizing the number of mice needed and increasing the statistical power by using each mouse as its own control.

This paper describes a striaghforward and efficient method of intubating mice for pulmonary function measurements or pulmonary instillation, that allows the mice to recover and be studied at later times. The procedure involves an inexpensive fiberoptic light source that directly illuminates the trachea.

A  simple procedure to intubate mice for pulmonary function measurements would  have several advantages in longitudinal studies with limited numbers or  ...

Repeated Measurement of Respiratory Muscle Activity and Ventilation in Mouse Models of Neuromuscular Disease

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated measurements over weeks or months of accessory respiratory muscle activity while simultaneously measuring ventilation in a non-anesthetized, freely behaving mouse. The technique includes the surgical implantation of a radio transmitter and the insertion of electrode leads into the scalene and trapezius muscles to measure the electromyogram activity of these inspiratory muscles. Ventilation is measured by whole-body plethysmography, and animal movement is assessed by video and is synchronized with electromyogram activity. Measurements of muscle activity and ventilation in a mouse model of amyotrophic lateral sclerosis are presented to show how this tool can be used to investigate how respiratory muscle activity changes over time and to assess the impact of muscle activity on ventilation. The described methods can easily be adapted to measure the activity of other muscles or to assess accessory respiratory muscle activity in additional mouse models of disease or injury.

This paper introduces a method for repeated measurements of ventilation and respiratory muscle activity in a freely behaving amyotrophic lateral sclerosis (ALS) mouse model throughout disease progression with whole-body plethysmography and electromyography via an implanted telemetry device.

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated ...

Neonatal Murine Cochlear Explant Technique as an In Vitro Screening Tool in Hearing Research

While there have been remarkable advances in hearing research over the past few decades, there is still no cure for Sensorineural Hearing Loss (SNHL), a condition that typically involves damage to or loss of the delicate mechanosensory structures of the inner ear. Sophisticated in vitro and ex vivo assays have emerged in recent years, enabling the screening of an increasing number of potentially therapeutic compounds while minimizing resources and accelerating efforts to develop cures for SNHL. Though homogenous cultures of certain cell types continue to play an important role in current research, many scientists now rely on more complex organotypic cultures of murine inner ears, also known as cochlear explants. The preservation of organized cellular structures within the inner ear facilitates the in situ evaluation of various components of the cochlear infrastructure, including inner and outer hair cells, spiral ganglion neurons, neurites, and supporting cells. Here we present the preparation, culture, treatment, and immunostaining of neonatal murine cochlear explants. The careful preparation of these explants facilitates the identification of mechanisms that contribute to SNHL and constitutes a valuable tool for the hearing research community.

Neonatal Murine Cochlear Explant Technique as an In Vitro Screening Tool in Hearing Research

The goal of this protocol is to demonstrate the preparation, culture, treatment, and immunostaining of neonatal murine cochlear explants. The technique can be utilized as an in vitro screening tool in hearing research.

While there have been remarkable advances in hearing research over the past few decades, there is still no cure for Sensorineural Hearing Loss (SNHL), a ...

On-Site Sampling and Extraction of Brain Tumors for Metabolomics and Lipidomics Analysis

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still in need. In recent years, mass spectrometry has become a method of choice for untargeted profiling of discriminatory compound as potential biomarkers of a disease. Biofluids are generally considered as preferable matrices given their accessibility and easier sample processing while direct tissue profiling provides more selective information about a given cancer. Preparation of tissues for the analysis via traditional methods is much more complex and time-consuming, and, therefore, not suitable for fast on-site analysis. The current work presents a protocol combining sample preparation and extraction of small molecules on-site, immediately after tumor resection. The sampling device, which is of the size of an acupuncture needle, can be inserted directly into the tissue and then transported to the nearby laboratory for instrumental analysis. The results of metabolomics and lipidomics analyses demonstrate the capability of the approach for the establishment of phenotypes of tumors related to the histological origin of the tumor, malignancy, and genetic mutations, as well as for the selection of discriminating compounds or potential biomarkers. The non-destructive nature of the technique permits subsequent performance of routinely used tests e.g., histological tests, on the same samples used for SPME analysis, thus enabling attainment of more comprehensive information to support personalized diagnostics.

The manuscript presents on-site sampling of human brain tumors with solid phase microextraction followed by their biochemical profiling towards the discovery of biomarkers.

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still ...

A Neonatal BALB/c Mouse Model of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight infants, with high mortality and unclear pathogenesis. The cause of NEC may be related to inflammatory immune regulatory system abnormalities. An NEC animal model is an indispensable tool for NEC disease immune research. NEC animal models usually use C57BL/6J neonatal mice; BALB/c neonatal mice are rarely used. Related studies have shown that when mice are infected, Th2 cell differentiation is predominant in BALB/c mice compared to C57BL/6J mice. Studies have suggested that the occurrence and development of NEC are associated with an increase in T helper type 2 (Th2) cells and are generally accompanied by infection. Therefore, this study used neonatal BALB/c mice to induce an NEC model with similar clinical characteristics and intestinal pathological changes as those observed in children with NEC. Further study is warranted to determine whether this animal model could be used to study Th2 cell responses in NEC.

Necrotizing enterocolitis (NEC) is the most severe gastrointestinal (GI) disease that often occurs in premature infants, especially very low birth weight ...

Developing an Exercise Program for Rheumatoid Arthritis Patients

Evaluation of Changes in Hydration and Body Cell Mass with Bioelectrical Impedance Analysis after Exercise Program for Rheumatoid Arthritis Patients

Rheumatoid arthritis (RA) is a debilitating disease that can result in complications such as rheumatoid cachexia. While physical exercise has shown benefits for RA patients, its impact on hydration and body cell mass remains uncertain. The presence of pain, inflammation, and joint changes often restrict activity and make traditional body composition assessments unreliable due to altered hydration levels. Bioelectrical impedance is a commonly used method for estimating body composition, but it has limitations since it was primarily developed for the general population and does not consider changes in body composition. On the other hand, bioelectrical impedance vectorial analysis (BIVA) offers a more comprehensive approach. BIVA involves graphically interpreting resistance (R) and reactance (Xc), adjusted for height, to provide valuable information about hydration status and the integrity of the cell mass.
Twelve women with RA were included in this study. At the beginning of the study, hydration and body cell mass measurements were obtained using the BIVA method. Subsequently, the patients participated in a six-month dynamic exercise program encompassing cardiovascular capacity, strength, and coordination training. To evaluate changes in hydration and body cell mass, the differences in the R and Xc parameters, adjusted for height, were compared using BIVA confidence software. The results showed notable changes: resistance decreased after the exercise program, while reactance increased. BIVA, as a classification method, can effectively categorize patients into dehydration, overhydration, normal, athlete, thin, cachectic, and obese categories. This makes it a valuable tool for assessing RA patients, as it provides information independent of body weight or prediction equations. Overall, the implementation of BIVA in this study shed light on the effects of the exercise program on hydration and body cell mass in RA patients. Its advantages lie in its ability to provide comprehensive information and overcome the limitations of traditional body composition assessment methods.

Author Spotlight: Implementation of BIVA for Analyzing Disease Risk Factors in Patients with Low Body Cell Mass 

This protocol assesses alterations in hydration and body cell mass status using bioelectrical impedance vectorial analysis following a dynamic exercise program designed for patients with rheumatoid arthritis. The dynamic exercise program itself is detailed, highlighting its components focused on cardiovascular capacity, strength, and coordination. The protocol details steps, instruments, and limitations.

Rheumatoid arthritis (RA) is a debilitating disease that can result in complications such as rheumatoid cachexia. While physical exercise has shown ...