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RNA aptamer probes as optical imaging agents for the detection of amyloid plaques.

Farrar CT, William CM, Hudry E, Hashimoto T, Hyman BT - PLoS ONE (2014)

Bottom Line: We examined the possibility of developing highly specific and sensitive optical imaging agents using aptamer technology.Dot blots of synthetic Aβ aggregates provide further evidence that β55 binds both fibrillar and non-fibrillar Aβ.The high binding affinity, the ease of probe development, and the ability to incorporate multiple and multimodal imaging reporters suggest that RNA aptamers may have complementary and perhaps advantageous properties compared to conventional optical imaging probes and reporters.

View Article: PubMed Central - PubMed

Affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America.

ABSTRACT
Optical imaging using multiphoton microscopy and whole body near infrared imaging has become a routine part of biomedical research. However, optical imaging methods rely on the availability of either small molecule reporters or genetically encoded fluorescent proteins, which are challenging and time consuming to develop. While directly labeled antibodies can also be used as imaging agents, antibodies are species specific, can typically not be tagged with multiple fluorescent reporters without interfering with target binding, and are bioactive, almost always eliciting a biological response and thereby influencing the process that is being studied. We examined the possibility of developing highly specific and sensitive optical imaging agents using aptamer technology. We developed a fluorescently tagged anti-Aβ RNA aptamer, β55, which binds amyloid plaques in both ex vivo human Alzheimer's disease brain tissue and in vivo APP/PS1 transgenic mice. Diffuse β55 positive halos, attributed to oligomeric Aβ, were observed surrounding the methoxy-XO4 positive plaque cores. Dot blots of synthetic Aβ aggregates provide further evidence that β55 binds both fibrillar and non-fibrillar Aβ. The high binding affinity, the ease of probe development, and the ability to incorporate multiple and multimodal imaging reporters suggest that RNA aptamers may have complementary and perhaps advantageous properties compared to conventional optical imaging probes and reporters.

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Related in: MedlinePlus

β55 Staining of Dot Blots of Synthetic Aβ Aggregates.(a) Dot blot of synthetic Aβ1–42 and Aβ1–40 aggregates probed with biotinylated-β55. (b) Western blot of the synthetic Aβ1–42 and Aβ1–40 aggregates probed with 6E10 antibody. The increased staining of Aβ1–42 aggregates in the dot blot relative to Aβ1–40 aggregates is consistent with the greater fibril and high molecular weight oligomer composition of Aβ1–42 aggregates observed in the western blot.
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pone-0089901-g003: β55 Staining of Dot Blots of Synthetic Aβ Aggregates.(a) Dot blot of synthetic Aβ1–42 and Aβ1–40 aggregates probed with biotinylated-β55. (b) Western blot of the synthetic Aβ1–42 and Aβ1–40 aggregates probed with 6E10 antibody. The increased staining of Aβ1–42 aggregates in the dot blot relative to Aβ1–40 aggregates is consistent with the greater fibril and high molecular weight oligomer composition of Aβ1–42 aggregates observed in the western blot.

Mentions: Dot blots of synthetic Aβ1–40 and Aβ1–42 that were incubated at 37°C for 3 days were performed to examine the binding of β55 to different Aβ species. β55 staining of both Aβ1–40 and Aβ1–42 was observed (Figure 3a). The increased staining observed for Aβ1–42 is consistent with the increased propensity of Aβ1–42 to form high molecular weight (HMW) species relative to Aβ1–40 as shown in the 6E10 western blot of the synthetic Aβ reactions (Figure 3b), where no HMW species were observed for Aβ1–40.


RNA aptamer probes as optical imaging agents for the detection of amyloid plaques.

Farrar CT, William CM, Hudry E, Hashimoto T, Hyman BT - PLoS ONE (2014)

β55 Staining of Dot Blots of Synthetic Aβ Aggregates.(a) Dot blot of synthetic Aβ1–42 and Aβ1–40 aggregates probed with biotinylated-β55. (b) Western blot of the synthetic Aβ1–42 and Aβ1–40 aggregates probed with 6E10 antibody. The increased staining of Aβ1–42 aggregates in the dot blot relative to Aβ1–40 aggregates is consistent with the greater fibril and high molecular weight oligomer composition of Aβ1–42 aggregates observed in the western blot.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3935954&req=5

pone-0089901-g003: β55 Staining of Dot Blots of Synthetic Aβ Aggregates.(a) Dot blot of synthetic Aβ1–42 and Aβ1–40 aggregates probed with biotinylated-β55. (b) Western blot of the synthetic Aβ1–42 and Aβ1–40 aggregates probed with 6E10 antibody. The increased staining of Aβ1–42 aggregates in the dot blot relative to Aβ1–40 aggregates is consistent with the greater fibril and high molecular weight oligomer composition of Aβ1–42 aggregates observed in the western blot.
Mentions: Dot blots of synthetic Aβ1–40 and Aβ1–42 that were incubated at 37°C for 3 days were performed to examine the binding of β55 to different Aβ species. β55 staining of both Aβ1–40 and Aβ1–42 was observed (Figure 3a). The increased staining observed for Aβ1–42 is consistent with the increased propensity of Aβ1–42 to form high molecular weight (HMW) species relative to Aβ1–40 as shown in the 6E10 western blot of the synthetic Aβ reactions (Figure 3b), where no HMW species were observed for Aβ1–40.

Bottom Line: We examined the possibility of developing highly specific and sensitive optical imaging agents using aptamer technology.Dot blots of synthetic Aβ aggregates provide further evidence that β55 binds both fibrillar and non-fibrillar Aβ.The high binding affinity, the ease of probe development, and the ability to incorporate multiple and multimodal imaging reporters suggest that RNA aptamers may have complementary and perhaps advantageous properties compared to conventional optical imaging probes and reporters.

View Article: PubMed Central - PubMed

Affiliation: Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, United States of America.

ABSTRACT
Optical imaging using multiphoton microscopy and whole body near infrared imaging has become a routine part of biomedical research. However, optical imaging methods rely on the availability of either small molecule reporters or genetically encoded fluorescent proteins, which are challenging and time consuming to develop. While directly labeled antibodies can also be used as imaging agents, antibodies are species specific, can typically not be tagged with multiple fluorescent reporters without interfering with target binding, and are bioactive, almost always eliciting a biological response and thereby influencing the process that is being studied. We examined the possibility of developing highly specific and sensitive optical imaging agents using aptamer technology. We developed a fluorescently tagged anti-Aβ RNA aptamer, β55, which binds amyloid plaques in both ex vivo human Alzheimer's disease brain tissue and in vivo APP/PS1 transgenic mice. Diffuse β55 positive halos, attributed to oligomeric Aβ, were observed surrounding the methoxy-XO4 positive plaque cores. Dot blots of synthetic Aβ aggregates provide further evidence that β55 binds both fibrillar and non-fibrillar Aβ. The high binding affinity, the ease of probe development, and the ability to incorporate multiple and multimodal imaging reporters suggest that RNA aptamers may have complementary and perhaps advantageous properties compared to conventional optical imaging probes and reporters.

Show MeSH
Related in: MedlinePlus