Journal: Kidney International
Article Title: Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular filtration barrier function in early diabetic kidney disease
doi: 10.1016/j.kint.2019.09.035
Figure Lengend Snippet: Syndecan-4 ( S dc 4 ) mRNA and protein are altered in early diabetic kidney disease (DKD). Glomerular endothelial cells (GECs) were sorted by fluorescence-activated cell sorting, and ( a ) S dc 4 and ( b ) S dc 1 mRNA expression were determined. The 2 −ΔΔCT method of quantification was used to calculate the fold change, normalized to glyceraldehyde-3-phosphate dehydrogenase, at week 8 post-streptozotocin (STZ), ( S dc 4 : control, 1.000 ± 0.2565, n = 9 mice; diabetes, 2.470 ± 0.6580, n = 8 mice; * P < 0.05; S dc 1 : control, 1.000 ± 0.1112, n = 5 mice; diabetes, 1.663 ± 0.4289, n = 5 mice; nonsignificant [NS]). Control and diabetic kidney sections were labeled with SDC4 and endothelial membrane label R18. ( c ) Peak-to-peak assessment of the glomerular endothelial glycocalyx using SDC4 labeling at week 9 post-STZ showed a significant reduction in glycocalyx SDC4 in diabetes (control, 182.5 ± 12.04, n = 5 mice; diabetes, 64.31 ± 6.513, n = 5 mice; *** P < 0.0001). Isolated glomerular lysates from control and diabetic mice were used to determine ( d ) SDC4 and ( e ) SDC1 concentration using SDC4 and SDC1 ectodomain enzyme-linked immunosorbent assay (ELISA). The data were then normalized to total protein content. SDC4 (control, 1.327 ± 0.1439, n = 6 mice; diabetes, 0.8059 ± 0.1218, n = 6 mice; * P < 0.05); SDC1 (control, 9.671 ± 1.742, n = 6 mice; diabetes, 9.699 ± 1.313, n = 6 mice; NS) at week 8 post-STZ. SDC4 shedding in the ( f ) plasma and ( g ) urine was determined in DKD using the SDC4 ectodomain ELISA at week 8 post-STZ. For plasma: control, 2.631 ± 0.2860, n = 6 mice; diabetes, 4.801 ± 0.3793, n = 6 mice; ** P < 0.005. Urine SDC4 was normalized to creatinine (control, 3.343 ± 0.9410, n = 4 mice; diabetes, 39.32 ± 13.03, n = 4 mice; * P < 0.05; Mann-Whitney test at week 8 post-STZ). Each dot or square on the graph represents a mouse. Data are expressed as the mean ± SEM, and unpaired Student t test was used for statistical analysis unless specified.
Article Snippet: The concentrations of SDC4 (ectodomain) in mouse glomerular lysate, plasma, and urine were quantified using a sandwich enzyme immunoassay (mouse SDC4 ELISA kit, CSB-EL020891MO; Cusabio, Houston, TX) according to the manufacturer’s instructions.
Techniques: Fluorescence, FACS, Expressing, Control, Labeling, Membrane, Isolation, Concentration Assay, Enzyme-linked Immunosorbent Assay, Clinical Proteomics, MANN-WHITNEY