Chemical Imaging of Retinal Pigment Epithelium in Frozen Sections of Zebrafish Larvae Using ToF-SIMS
- Van Nuffel, S., Ang, K.C., Lin, A.Y., Cheng, K.C.
- Journal of the American Society for Mass Spectrometry 32(1): 255-261 (Journal)
- Registered Authors
- Cheng, Keith C.
- MeSH Terms
- Cryoelectron Microscopy
- Image Processing, Computer-Assisted/methods
- Molecular Imaging/methods*
- Principal Component Analysis
- Retinal Pigment Epithelium/chemistry
- Retinal Pigment Epithelium/diagnostic imaging*
- Spectrometry, Mass, Secondary Ion/methods*
- 33112610 Full text @ J. Am. Soc. Mass Spectrom.
Van Nuffel, S., Ang, K.C., Lin, A.Y., Cheng, K.C. (2020) Chemical Imaging of Retinal Pigment Epithelium in Frozen Sections of Zebrafish Larvae Using ToF-SIMS. Journal of the American Society for Mass Spectrometry. 32(1):255-261.
Variants of the SLC24A5 gene, which encodes a putative potassium-dependent sodium-calcium exchanger (NCKX5) that most likely resides in the melanosome or its precursor, affect pigmentation in both humans and zebrafish (Danio rerio). This finding suggests that genetic variations influencing human skin pigmentation alter melanosome biogenesis via ionic changes. Gaining an understanding of how changes in the ionic environment of organelles impact melanosome morphogenesis and pigmentation will require a spatially resolved way to characterize the chemical environment of melanosomes in pigmented tissue such as retinal pigment epithelium (RPE). The imaging mass spectrometry technique most suited for this type of cell and tissue analysis is time-of-flight secondary ion mass spectrometry (ToF-SIMS) because it is able to detect many biochemical species with high sensitivity and with submicron spatial resolution. Here, we describe chemical imaging of the RPE in frozen-hydrated sections of larval zebrafish using cryo-ToF-SIMS. To facilitate the data interpretation, positive and negative polarity ToF-SIMS image data were transformed into a single hyperspectral data set and analyzed using principal component analysis. The combination of a novel protocol and the use of multivariate data analysis allowed us to discover new marker ions that are attributable to leucodopachrome, a metabolite specific to the biosynthesis of eumelanin. The described methodology may be adapted for the investigation of other classes of molecules in frozen tissues from zebrafish and other organisms.
Genes / Markers
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes