Use of lectin microarray to differentiate gastric cancer from gastric ulcer

AIM: To investigate the feasibility of lectin microarray for differentiating gastric cancer from gastric ulcer. METHODS: Twenty cases of human gastric cancer tissue and 20 cases of human gastric ulcer tissue were collected and processed. Protein was extracted from the frozen tissues and stored. The lectins were dissolved in buffer, and the sugar-binding specificities of lectins and the layout of the lectin microarray were summarized. The median of the effective data points for each lectin was globally normalized to the sum of medians of all effective data points for each lectin in one block. Formalin-fixed paraffin-embedded gastric cancer tissues and their corresponding gastric ulcer tissues were subjected to Ag retrieval. Biotinylated lectin was used as the primary antibody and HRP-streptavidin as the secondary antibody. The glycopatterns of glycoprotein in gastric cancer and gastric ulcer specimens were determined by lectin microarray, and then validated by lectin histochemistry. Data are presented as mean +/- SD for the indicated number of independent experiments. RESULTS: The glycosylation level of gastric cancer was significantly higher than that in ulcer. In gastric cancer, most of the lectin binders showed positive signals and the intensity of the signals was stronger, whereas the opposite was the case for ulcers. Significant differences in the pathological score of the two lectins were apparent between ulcer and gastric cancer tissues using the same lectin. For MPL and VVA, all types of gastric cancer detected showed stronger staining and a higher positive rate in comparison with ulcer, especially in the case of signet ring cell carcinoma and intra-mucosal carcinoma. GalNAc bound to MPL showed a significant increase. A statistically significant association between MPL and gastric cancer was observed. As with MPL, there were significant differences in VVA staining between gastric cancer and ulcer. CONCLUSION: Lectin microarray can differentiate the different glycopatterns in gastric cancer and gastric ulcer, and the lectins MPL and VVA can be used as biomarkers. (C) 2014 Baishideng Publishing Group Co., Limited. All rights reserved.

Possible role of sialylation of retinal protein glycans in the regulation of electroretinogram response in mice

AIM： To evaluate if the nature, degree and extent of Siaa2-3-/Siaa2-6-sialylation of retinal protein glycans plays a possible role in the development and regulation of electroretinogram response （ERG） in mice. METHODS： Proteins extracted, from retinae of postnatal day 2 （PN2）, PN7, and PN14 wild type （wt） and retinal degeneration 1 （rdl） mice were quantified, labeled and used for lectin-microarray profiling with immobilized lectins which recognize a wide range of N-/O-glycans. Net fluorescence intensities of lectin-ligand complexes were measured and images of fluorescent lectin-microarrays were acquired. From the binding curves between each lectin and protein extracts from PN14 wt and PN14 rdl mice retinae, the protein concentration was selected to determine optimum signal intensity for lectin-ligand binding. Mean_＋SEM values of proteins and fluorescence- intensities of lectin-ligand-complexes between 45 lectins and 36 protein extracts from wt and rdl mice retinae were compared for significance of differences. RESULTS： Comparison of the progressive relative changes in the sialylated glycans of retinal proteins from wt and rdl mice showed that Siao2-3Gall-4GIcNAc-glycans （but not Siaa2-6-glycans） were detectable and quantifiable from the retinal-proteins of PN7 and PN14 wt and rdl mice. Siaa2- 3-sialylation of retinal-protein Gal/o-linked-Gal-glycans was significantly increased with age in PN7 and PN14 wt and less so in PN14 rdl mice. Siao2-3-/Siaa2-6-sialylation of retinal-protein Gal/a-linked-Gal-glycans was absent in PN2 wt and rdl mice. Comparison of published ERG responses of wt and rdl mice retinae with degree of Siaa2- 3-sialylation of retinal-protein-glycans showed that PN2 wt and rdl mice lack both the ERG response and Siaa2- 3-/Siao2-6-sialylation of retinal-protein Gal/a-linked-Gal-glycans; rdl mice with relatively lower Siaa2-3-sialylation of retinal-protein Gal/a-linked-Gal-glycans showed aberrant ERG response; and wt mice with significantly higher Siaa2-3-sialylation of retinal-protein Gal/a-linked- Gal-glycans showed normal ERG response. CONCLUSION： Degree of Siaa2-3-sialylation of giycans possibly regulates ERG function in mice.

Functional protein microarray： an ideal platform for investigating protein binding property

Functional protein microarray is an important tool for high-throughput and large-scale systems biology studies. Besides the progresses that have been made for protein microarray fabrication, significant advancements have also been achieved for applying protein microarrays on determining a variety of protein biochemical activities. Among these applications, detection of protein binding properties, such as protein-protein interactions （PPIs）, protein-DNA interactions （PDIs）, protein-RNA interactions, and antigen-antibody interactions, are straightforward and have substantial impacts on many research fields. In this review, we will focus on the recent progresses in protein-protein, protein-DNA, protein-RNA, protein-small molecule, protein-lipid, protein-glycan, and antigen-antibody interactions. We will also discuss the challenges and future directions of protein microarray technologies. We strongly believe that protein microarrays will soon become an indispensible tool for both basic research and clinical applications.

Effects of Cryopreservation on Human Sperm Glycocalyx

Background:To study the effects of cryopreservation on human sperm glycocalyx.Methods:The lectin binding profilings of sperm after freeze-thaw were compared by lectin microarray.Results:CryoSperm^(TM) and direct fumigation were confirmed to be the optimized cryoprotectant and method by comparing the sperm recovery rate.In 91 lectins,33 lectins were significantly changed after sperm cryopreservation.Among them,9 lectins greatly decreased and 24 lectins mainly increased.The binding signals of MAA,PSA,ABA,and AIA were verified by FACS,and the results were consistent with that of lectin microarray.Conclusions:Sperm glycocalyx had significant changes after cryopreservation.The sialic acid,playing an important role in protecting sperm,was greatly lost,which exposed the inner carbohydrates.Thus,the glycocalyx damage due to the cryopreservation might be one of the reasons for low sperm fertility.