2013年10月アーカイブ

As far as we know, this paper will be the first study to perform glycan profiling of urines samples from the patients with diabetic nephropathy. As a result of their glycan profiling study using lectin microarrays, they found global reduction of the bindings to lectins, such as fucose, Lac/LacNA, α- or β-Gal, chitobiose, and α- or β-GalNAc binders in urine samples of diabetic nephropathy at macroalbuminuria stage. Unlike the reduced bindings to these lectins, interestingly the biding activity to Siaα2-6-Gal/GalNAc binders progressively increased at micro- and macroalbuminruia stages.

Then, by capturing Siaα2-6Gal/GalNAc modified glycoproteins with SNA- and SNA-agarose column chromatography, they finaly concluded that higher urinary fetuin-A excretion demonstrated a higher risk for the development of microalbuminuria and reduction of renal function.

Urinary Fetuin-A Is a Novel Marker for Diabetic Nephropathy in Type 2 Diabetes Identified by Lectin Microarray

Have a fun!

 

In the interpretation of glycan profiling patterns (i.e., glycan profiles) taken by lectin microarrays, I have summarized important things and procedures as follows.

1. Some sort of normalization is absolutely necessary in comparing glycan profiles differentially. One of the most useful normalization methods is "Average Normalization". In this case, all of the lectin signals are devided by the average of all lectins on the array, and for convenience, the values are then multiplied by 100.

 

2. And, the differences in glycan profiles are interpreted taking lectin binding characteristics and CV (coefficient of variation) into consideration. Usually the CV is less than 10% in a lot, and that of lot-to-lot variation gets a little bit bigger than this. Lectin binding specificity is not one-to-one relationship like an antigen-antibody reaction, but is fairly broader than that. So, we must be careful in the interpretation if other lectins with similar binding characteristics are reacting in the same way or not, taking each binding specificity into consideration. As for the lectin binding characteristics, please refer to Table 2 shown on page 4448 in the following paper "Lectin microarrays: concept, principle and applications" for your information. Lectin microarrays: concept, principle and applications

 

3. In some cases, enzymatic digestion is very useful in understanding glycan profiles. For instance, vague points in the interpretation get clearer by comparing before and after sialidase digestion and by repeating the enzymatic digestion with galactosidase, acetylhexosaminidase, mannosidase in sequence. A figure 4 shown on page 854 in the following paper "Evanescent-field fluorescence-assisted lectin microarray: a new strategy for glycan profiling" would be such a very good example. Evanescent-field fluorescence-assisted lectin microarray: a new strategy for glycan profiling

 

LecChip_ScanImage.jpg

So, if you have any questions, please feel free to write an email to us anything, info@glycotechnica.com.

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