| 1. |
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| 2. |
- Abramsson, Alexandra, 1973, et al.
(author)
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Defective N-sulfation of heparan sulfate proteoglycans limits PDGF-BB binding and pericyte recruitment in vascular development
- 2007
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In: GENES & DEVELOPMENT. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 21:3, s. 316-331
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Journal article (peer-reviewed)abstract
- During vascular development, endothelial platelet-derived growth factor B (PDGF-B) is critical for pericyte recruitment. Deletion of the conserved C-terminal heparin-binding motif impairs PDGF-BB retention and pericyte recruitment in vivo, suggesting a potential role for heparan sulfate (HS) in PDGF-BB function during vascular development. We studied the participation of HS chains in pericyte recruitment using two mouse models with altered HS biosynthesis. Reduction of N-sulfation due to deficiency in N-deacetylase/N-sulfotransferase-1 attenuated PDGF-BB binding in vitro, and led to pericyte detachment and delayed pericyte migration in vivo. Reduced N-sulfation also impaired PDGF-BB signaling and directed cell migration, but not proliferation. In contrast, HS from glucuronyl C5-epimerase mutants, which is extensively N- and 6-O-sulfated, but lacks 2-O-sulfated L-iduronic acid residues, retained PDGF-BB in vitro, and pericyte recruitment in vivo was only transiently delayed. These observations were supported by in vitro characterization of the structural features in HS important for PDGF-BB binding. We conclude that pericyte recruitment requires HS with sufficiently extended and appropriately spaced N-sulfated domains to retain PDGF-BB and activate PDGF receptor β (PDGFRβ) signaling, whereas the detailed sequence of monosaccharide and sulfate residues does not appear to be important for this interaction.
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| 3. |
- Al-Amin, Rasel A., Researcher, 1983-, et al.
(author)
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Monitoring drug–target interactions through target engagement-mediated amplification on arrays and in situ
- 2022
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In: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 50:22, s. e129-e129
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Journal article (peer-reviewed)abstract
- Drugs are designed to bind their target proteins in physiologically relevant tissues and organs to modulate biological functions and elicit desirable clinical outcomes. Information about target engagement at cellular and subcellular resolution is therefore critical for guiding compound optimization in drug discovery, and for probing resistance mechanisms to targeted therapies in clinical samples. We describe a target engagement-mediated amplification (TEMA) technology, where oligonucleotide-conjugated drugs are used to visualize and measure target engagement in situ, amplified via rolling-circle replication of circularized oligonucleotide probes. We illustrate the TEMA technique using dasatinib and gefitinib, two kinase inhibitors with distinct selectivity profiles. In vitro binding by the dasatinib probe to arrays of displayed proteins accurately reproduced known selectivity profiles, while their differential binding to fixed adherent cells agreed with expectations from expression profiles of the cells. We also introduce a proximity ligation variant of TEMA to selectively investigate binding to specific target proteins of interest. This form of the assay serves to improve resolution of binding to on- and off-target proteins. In conclusion, TEMA has the potential to aid in drug development and clinical routine by conferring valuable insights in drug–target interactions at spatial resolution in protein arrays, cells and in tissues.
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| 4. |
- Al-Amin, Rasel A., 1983-, et al.
(author)
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Target Engagement-Mediated Amplification for Monitoring Drug-Target Interactions in Situ
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Other publication (other academic/artistic)abstract
- It is important to determine the localization of drugs or drug candidates at cellular and subcellular resolution in relevant clinical specimens. This is necessary to evaluate drug candidates from early stages of drug development to clinical evaluation of mutations potentially causing resistance to targeted therapy. We describe a technology where oligonucleotide-conjugated drug molecules are used to visualize and measure target engagement in situ via rolling-circle amplification (RCA) of circularized oligonucleotide probes (padlock probes). We established this target engagement-mediated amplification (TEMA) technique using kinase inhibitor precursor compounds, and we applied the assay to investigate target interactions by microscopy in pathology tissue sections and using flow cytometry for blood samples from patients, as well as in commercial arrays including almost half of all human proteins. In the variant proxTEMAtechnique, in situ proximity ligation assays were performed by combining drug-DNA conjugates with antibody-DNA conjugates to specifically reveal drug binding to particular on- or off-targets in pathological tissues sections. In conclusion, the TEMA methods successfully visualize drug-target interaction by experimental and clinically approved kinase inhibitors in situ and with kinases among a large collection of arrayed proteins.
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| 5. |
- de Oliveira, Felipe, 1984-, et al.
(author)
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Autoimmunity detection via proximity assays
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Other publication (other academic/artistic)abstract
- Since autoantibodies are recognized as valuable biomarkers for clinical diagnostics and prognostics in autoimmune diseases such as Stiff Person Syndrome (SPS) and Type 1 diabetes, detection of such markers at improved sensitivity and specificity could be of significant interest. In addition, as proximity assays have been shown to offer highly sensitive and specific detection of multiple proteins, the technique could be expanded to applications for autoimmunity detection. In the present study, we have applied the newly developed proximity ligation assay with rolling circle amplification (PLARCA), and proximity extension assay (PEA) for the detection of GADA, autoantibodies specific for glutamic acid decarboxylase 65 (GAD65). Through the use of oligonucleotide conjugated autoantigen GAD65 and anti-human antibodies, as proximity probes, we were able to apply these proximity assays to detect GADA in a set of SPS patient samples. In summary, we have applied and established both PLARCA and PEA, as a proof of concept, for the use of the specific and sensitive autoimmune detection.
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| 6. |
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| 7. |
- Lagerström-Fermér, Maria, et al.
(author)
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Amelogenin signal peptide mutation : correlation between mutations in the amelogenin gene (AMGX) and manifestations of X-linked amelogenesis imperfecta
- 1995
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In: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 26:1, s. 159-162
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Journal article (peer-reviewed)abstract
- Formation of tooth enamel is a poorly understood biological process. In this study we describe a 9-bp deletion in exon 2 of the amelogenin gene (AMGX) causing X-linked hypoplastic amelogenesis imperfecta, a disease characterized by defective enamel. The mutation results in the loss of 3 amino acids and exchange of 1 in the signal peptide of the amelogenin protein. This deletion in the signal peptide probably interferes with translocation of the amelogenin protein during synthesis, resulting in the thin enamel observed in affected members of the family. We compare this mutation to a previously reported mutation in the amelogenin gene that causes a different disease phenotype. The study illustrates that molecular analysis can help explain the various manifestations of a tooth disorder and thereby provide insights into the mechanisms of tooth enamel formation.
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| 8. |
- Lagerström-Fermér, Maria, et al.
(author)
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X-linked recessive panhypopituitarism associated with a regional duplication in Xq25-q26
- 1997
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In: American Journal of Human Genetics. - 0002-9297 .- 1537-6605. ; 60:4, s. 910-916
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Journal article (peer-reviewed)abstract
- We present a linkage analysis and a clinical update on a previously reported family with X-linked recessive panhypopituitarism, now in its fourth generation. Affected members exhibit variable degrees of hypopituitarism and mental retardation. The markers DXS737 and DXS1187 in the q25-q26 region of the X chromosome showed evidence for linkage with a peak LOD score (Zmax) of 4.12 at zero recombination fraction (theta(max) = 0). An apparent extra copy of the marker DXS102, observed in the region of the disease gene in affected males and heterozygous carrier females, suggests that a segment including this marker is duplicated. The gene causing this disorder appears to code for a dosage-sensitive protein central to development of the pituitary.
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| 9. |
- Schallmeiner, Edith, et al.
(author)
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Sensitive protein detection via triple-binder proximity ligation assays
- 2007
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In: Nature Methods. - : Springer Science and Business Media LLC. - 1548-7091 .- 1548-7105. ; 4:2, s. 135-137
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Journal article (peer-reviewed)abstract
- The detection of weakly expressed proteins and protein complexes in biological samples represents a fundamental challenge. We have developed a new proximity-ligation strategy named 3PLA that uses three recognition events for the highly specific and sensitive detection of as little as a hundred molecules of the vascular endothelial growth factor (VEGF), the biomarkers troponin I, and prostate-specific antigen (PSA) alone or in complex with an inhibitor--demonstrating the versatility of 3PLA.
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| 10. |
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| 11. |
- Zhu, Lei, et al.
(author)
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Proximity ligation measurement of the complex between prostate specific antigen and alpha1-protease inhibitor
- 2009
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In: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 55:9, s. 1665-1671
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Journal article (peer-reviewed)abstract
- BACKGROUND: Prostate specific antigen (PSA)-alpha1-protease inhibitor complex (PSA-API) is a minor form of PSA in serum. It may be useful for prostate cancer (PCa) diagnosis, but its specific detection is hampered by nonspecific background. To avoid this, we developed an immunoassay for PSA-API based on proximity ligation. METHODS: We used a monoclonal antibody (mAb) to total PSA (tPSA) to capture PSA, while using another anti-tPSA mAb together with an anti-API mAb as probes. We measured PSA-API by quantification of amplified DNA strands conjugated to the probes. We measured serum PSA-API in 84 controls and 55 men with PCa who had PSA concentrations of 4.0-10 microg/L. RESULTS: The detection limit of the assay was 6.6 ng/L. The proportion of PSA-API to tPSA (%PSA-API) tended to be lower in men with PCa (2.8%) than without cancer (3.3%) but was not statistically significant (P = 0.363). When used alone, %PSA-API [area under the curve (AUC) 0.546] did not improve detection of PCa, whereas %fPSA (AUC 0.710) and the sum of %fPSA and %PSA-API (AUC 0.723) did. At 90% diagnostic sensitivity, the diagnostic specificity for cancer was not significantly better for %f PSA + %PSA-API than for %fPSA alone (36% vs 30%). CONCLUSIONS: Proximity ligation eliminated nonspecific background, enabling accurate measurement of PSA-API in serum specimens with moderately increased tPSA. The combined use of %PSA-API and %fPSA provided a modest improvement for PCa detection, but based on the current study cohort, it is uncertain whether the improvement has clinical utility.
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| 12. |
- Al-Amin, Abdullah, PhD student, 1983-
(author)
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Molecular Approaches to Explore Drug-Target Interactions
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Improved means to assess the clinical potential of drug candidates can critically influence development of new therapeutic entities, a central aim in medical life science. Drug discovery and development relies on construction and selection of small organic compounds or biological agents that bind targets of interest. This thesis includes new methodology to investigate target engagement - that is the tendency for these drugs and drug candidates to bind their intended target molecules versus any off-targets. This is a matter of great importance and current strong interest in the pharmaceutical industry as well as academically and an important aim for precision medicine. Paper I describes the target engagement-mediated amplification (TEMA) technique, an accurate, selective and physiological relevant techniques to monitor target binding by DNA-conjugated low molecular weight drug molecules. The DNA conjugated forms of the drugs are uniquely suited to accurately and sensitively reveal the binding characteristics of drugs directly in relevant tissues. Paper II describes the evaluation of cellular thermal shift assays (CETSA) by multiplex proximity extension assays (PEA), to sensitively measure binding of drugs to their proper targets and off-targets in minimal samples of cells and tissues, and for many targets and samples in parallel. The technique provides valuable advantages during drug development, and potentially also in clinical care. Paper III describes a high-throughput approach to use in situ proximity ligation assays to investigate protein interactions or modifications along with phenotypic responses to drugs or cytokines. The technique allows responses by large numbers of cells to be evaluated by automated microscopy and computer-based analysis. Our approach expands the scope for combined molecular and morphological profiling, offering an information-rich means to profile cellular responses to drugs and other agents at the single cell level.
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| 13. |
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| 14. |
- Al-Amin, Rasel A., PhD student, 1983-, et al.
(author)
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Sensitive Measurement of Drug-Target Engagement by a Cellular Thermal Shift Assay with Multiplex Proximity Extension Readout
- 2021
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 93:31, s. 10999-11009
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Journal article (other academic/artistic)abstract
- The ability to monitor target engagement in cellular contexts is a key for successful drug discovery and also valuable in clinical routine. A cellular thermal shift assay (CETSA) provides realistic information about drug binding in cells and tissues, revealing drug-target engagement in clinically relevant samples. The CETSA combined with mass spectrometry (MS) detection can be applied in the early hit identification phase to generate target engagement data for large sets of proteins. However, the analysis is slow, requires substantial amounts of the sample material, and often misses proteins of specific interest. Here, we combined the CETSA and the multiplex proximity extension assay (PEA) for analysis of target engagement of a set of 67 proteins from small amounts of the sample material treated with kinase inhibitors. The results were concordant with the corresponding analyses read out via MS. Our approach allows analyses of large numbers of specific target proteins at high sensitivity in limited sample aliquots. Highly sensitive multiplex CETSA-PEA assays are therefore promising for monitoring drug-target engagement in small sample aliquots in the course of drug development and potentially in clinical settings.
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| 15. |
- Al-Amin, Rasel Abdullah, Researcher, 1983-, et al.
(author)
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Sensitive protein detection using site-specifically oligonucleotide-conjugated nanobody reagents
- 2022
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In: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 98:28, s. 10054-10061
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Journal article (peer-reviewed)abstract
- High-quality affinity probes are critical for sensitive and specific protein detection, in particular for detection of protein biomarkers in the early phases of disease development. Proximity extension assays (PEAs) have been used for high-throughput multiplexed protein detection of up to a few thousand different proteins in one or a few microliters of plasma. Clonal affinity reagents can offer advantages over the commonly used polyclonal antibodies (pAbs) in terms of reproducibility and standardization of such assays. Here, we explore nanobodies (Nbs) as an alternative to pAbs as affinity reagents for PEA. We describe an efficient site-specific approach for preparing high-quality oligo-conjugated Nb probes via enzyme coupling using Sortase A (SrtA). The procedure allows convenient removal of unconjugated affinity reagents after conjugation. The purified high-grade Nb probes were used in PEA, and the reactions provided an efficient means to select optimal pairs of binding reagents from a group of affinity reagents. We demonstrate that Nb-based PEA (nano-PEA) for interleukin-6 (IL6) detection can augment assay performance, compared to the use of pAb probes. We identify and validate Nb combinations capable of binding in pairs without competition for IL6 antigen detection by PEA.
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| 16. |
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| 17. |
- Antson, D.O., et al.
(author)
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PCR-generated padlock probes detect single nucleotide variation in genomic DNA
- 2000
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In: Nucleic Acids Research. - 0305-1048 .- 1362-4962. ; 28:12, s. E58-
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Journal article (peer-reviewed)abstract
- Circularizing oligonucleotide probes, so-called padlock probes, have properties that should prove valuable in a wide range of genetic investigations, including in situ analyses, genotyping and measurement of gene expression. However, padlock probes can be difficult to obtain by standard oligonucleotide synthesis because they are relatively long and require intact 5'- and 3'-end sequences to function. We describe a PCR-based protocol for flexible small-scale enzymatic synthesis of such probes. The protocol also offers the advantage over chemical synthesis that longer probes can be made that are densely labeled with detectable functions, resulting in an increased detection signal. The utility of probes synthesized according to this protocol is demonstrated for the analysis of single nucleotide variations in human genomic DNA both in situ and in solution.
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| 18. |
- Arvidsson, Per I., et al.
(author)
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Öppenheten förstör chansen till patent
- 2015
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In: Svenska dagbladet. - Stockholm : Svenska Dagbladet AB & Co.. - 2001-3868.
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Journal article (pop. science, debate, etc.)
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| 19. |
- Banér, Johan, et al.
(author)
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Microarray-based molecular detection of foot-and-mouth disease, vesicular stomatitis and swine vesicular disease viruses, using padlock probes
- 2007
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In: Journal of Virological Methods. - : Elsevier BV. - 0166-0934 .- 1879-0984. ; 143:2, s. 200-206
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Journal article (peer-reviewed)abstract
- The World Organization for Animal Health (Office International des Epizooties, OIE) includes the diseases caused by foot-and-mouth disease virus (FMDV), swine vesicular disease virus (SVDV), and vesicular stomatitis virus (VSV), as "Diseases Notifiable to the OIE". Foot-and-mouth disease (FMD) outbreaks have severe economical as well as social effects and cannot be differentiated from the diseases caused by the other two viruses on the basis of clinical symptoms. Efficient laboratory techniques are therefore required for detection and identification of the viruses causing similar vesicular symptoms in swine. A rapid method is described using padlock probes and microarrays to detect simultaneously and differentiate the three viruses in a single reaction, as well as providing serotype information in cases of VSV infection. The padlock probe/microarray assay detected successfully and identified 39 cDNA samples of different origin representing the three viruses. The results were in complete agreement with identities and serotypes determined previously. This novel virus detection method is discussed in terms of usefulness and further development.
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| 20. |
- Banér, Johan, et al.
(author)
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Parallel gene analysis with allele-specific padlock probes and tag microarrays
- 2003
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In: Nucleic Acids Research. - 0305-1048 .- 1362-4962. ; 31:17, s. e103-
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Journal article (peer-reviewed)abstract
- Parallel, highly specific analysis methods are required to take advantage of the extensive information about DNA sequence variation and of expressed sequences. We present a scalable laboratory technique suitable to analyze numerous target sequences in multiplexed assays. Sets of padlock probes were applied to analyze single nucleotide variation directly in total genomic DNA or cDNA for parallel genotyping or gene expression analysis. All reacted probes were then co-amplified and identified by hybridization to a standard tag oligonucleotide array. The technique was illustrated by analyzing normal and pathogenic variation within the Wilson disease-related ATP7B gene, both at the level of DNA and RNA, using allele-specific padlock probes.
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| 21. |
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| 22. |
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| 23. |
- Beisvåg, Vidar, et al.
(author)
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Contributions of the EMERALD project to assessing and improving microarray data quality
- 2011
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In: BioTechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 50:1, s. 27-31
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Journal article (peer-reviewed)abstract
- While minimum information about a microarray experiment (MIAME) standards have helped to increase the value of the microarray data deposited into public databases like ArrayExpress and Gene Expression Omnibus (GEO), limited means have been available to assess the quality of this data or to identify the procedures used to normalize and transform raw data. The EMERALD FP6 Coordination Action was designed to deliver approaches to assess and enhance the overall quality of microarray data and to disseminate these approaches to the microarray community through an extensive series of workshops, tutorials, and symposia. Tools were developed for assessing data quality and used to demonstrate how the removal of poor-quality data could improve the power of statistical analyses and facilitate analysis of multiple joint microarray data sets. These quality metrics tools have been disseminated through publications and through the software package arrayQualityMetrics. Within the framework provided by the Ontology of Biomedical Investigations, ontology was developed to describe data transformations, and software ontology was developed for gene expression analysis software. In addition, the consortium has advocated for the development and use of external reference standards in microarray hybridizations and created the Molecular Methods (MolMeth) database, which provides a central source for methods and protocols focusing on microarray-based technologies.
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| 24. |
- Birgegård, Gunnar, 1944-, et al.
(author)
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Evaluation of beta globin mRNA as an early marker of haemoglobin response to epoetin treatment
- 2007
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In: Medical Oncology. - : Springer Science and Business Media LLC. - 1357-0560 .- 1559-131X. ; 24:3, s. 318-322
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Journal article (peer-reviewed)abstract
- Approximately 60% of anaemic cancer patients respond to epoetin treatment. An early marker of response would be valuable in order to avoid ineffective treatment. We have previously shown that beta globin mRNA increases rapidly after epoetin beta treatment of healthy controls. In the present study we have evaluated whether a change of this marker during the first 2 weeks of epoetin treatment could predict later Hb response in anaemic cancer patients. Twenty cancer patients with Hb <11 g/dl received epoetin beta (NeoRecormon®) 10,000 IU three times weekly during 6 weeks. Hb, reticulocytes and β-globin mRNA were followed. The latter was measured quantitatively using PCR via the 5′ nuclease assay. Eleven patients responded with a Hb increase of >1 g/dl, nine were nonresponders. All responders increased in β-globin mRNA within 2 weeks, mean 7.7× base-line. With a cut-off of an increase of 3× base-line value, we obtained a specificity of 45% and a sensitivity of 91% for the prediction of a later increase of Hb >1 g/dl. With a cut-off of 4× base-line, the specificity increased to 66%, but the sensitivity decreased to 82%. Beta globin mRNA increases before Hb in all responding patients. However, some non-responding patients also show an increase, and there is a trade-off between specificity and sensitivity as the cut-off level is set at different levels. Compared to reticulocyte count, β-globin mRNA is more reliable in the individual patient, but the clinical usefulness of the assay needs to be evaluated in further studies.
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| 25. |
- Björkesten, Johan, et al.
(author)
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A multiplex platform for digital measurement of circular DNA reaction products
- 2020
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In: Nucleic Acids Research. - : OXFORD UNIV PRESS. - 0305-1048 .- 1362-4962. ; 48:13
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Journal article (peer-reviewed)abstract
- Digital PCR provides high sensitivity and unprecedented accuracy in DNA quantification, but current approaches require dedicated instrumentation and have limited opportunities for multiplexing. Here, we present an isothermal platform for digital enumeration of DNA reaction products in multiplex via standard fluorescence microscopy. Circular DNA strands, which may result from a wide range of molecular detection reactions, are captured on streptavidin-coated surfaces via hybridized biotinylated primers, followed by rolling circle amplification (RCA). The addition of 15% polyethylene glycol 4000 during RCA resulted in uniform, easily recorded reaction products. Immobilized DNA circles were visualized as RCA products with 100% efficiency, as determined by droplet digital PCR. We confirmed previous reports about the influence on RCA by sequence composition and size of RCA templates, and we developed an efficient one-step restaining procedure for sequential multiplexing using toehold-triggered DNA strand displacement. Finally, we exemplify applications of this digital readout platform by demonstrating more than three orders of magnitude improved sensitivity by digital measurement of prostate specific antigen (PSA) (detection threshold similar to 100 pg/l), compared to a commercial enzyme-linked immunosorbent assay (ELISA) with analogue readout (detection threshold similar to 500 ng/l), using the same antibody pair.
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