Fig. 6: SMOC1 expression in human islets from non-diabetic (ND) and T2D donors and the effect in insulin secretion and β-cell identity genes.

Expression of a INS and b GCG in α-and β-cell clusters of adult human ND (red) and T2D islets (green) from the HPAP-HIRN dataset. In a ND = 17103 and T2D = 4873 biologically independent cells were analyzed. ND and T2D groups were separated by split.by parameter in Seurat’s VlnPlot function, and the statistical test done by the default two-sided Wilcox rank-sum (Mann-Whitney U) method with ggpubr package. For the ND group, the distribution was: min. = 0.00, 25th percentile = 7.55, median = 8.17, 75th percentile = 8.46, and max. = 8.86; and for the T2D group: min. = 0.00, 25th percentile = 7.55, median = 8.02, 75th percentile = 8.39, and max. = 8.82, from normalized expression level stored in RNA assay slot. In b ND = 7606 and T2D = 5661 biologically independent cells were analyzed. For the ND group, the distribution was: min. = 0.00, 25th percentile = 5.37, median = 6.02, 75th percentile = 6.57, and max. = 8.10; For the T2D group: min. = 0.00, 25th percentile = 5.68, median = 6.39, 75th percentile = 6.86, and max. = 8.24 from normalized expression level stored in RNA assay slot. For a and b, the p-value annotation legend assigned by default asterisk annotation in ggpubr package refers to: ns:0.05 < p < 1.0; *:0.01 < p < 0.05; **:0.001<p < 0.01; ***0.0001 < p < 0.001; ****p < 0.0001. c Expression of SMOC1 in α-and β-cell subclusters of adult human non-diabetic (red) and T2D islets (green). ns:0.05 < p < 1.0; *0.01 < p < 0.05; **0.001 < p < 0.01; ***0.0001 < p < 0.001; ****p < 0.0001. d Representative western blot of human islet protein extracts from adult human non-diabetic and T2D donors and quantitation of n = 3 different donors per condition. e Representative images of pancreas sections from adult human ND (n = 3) and T2D (n = 3) donors immunolabeled for DAPI (blue) and SMOC1 (red) and C-peptide (green), or SMOC1 (magenta) and glucagon (green). Enhanced image of the inset (box). f Quantitation of SMOC1 mRNA expression in adenovirus-CMV-GFP or adenovirus-CMV-SMOC1-GFP transduced human islet cells from adult human ND donors by qPCR (n = 8 different human islet donors). g. INS mRNA expression in these adenovirus-CMV-GFP or adenovirus-CMV-SMOC1-GFP transduced-cells by qPCR (n = 8 different human islet donors). h Insulin secretion index (ratio of insulin secretion at 16 mM and 5.5 mM corrected per insulin content) in adenovirus-CMV-GFP or adenovirus-CMV-SMOC1-GFP transduced-cells (n = 4 different human islet donors). i PDX-1, NKX6.1, MAFA, UCN3, GCK, GLUT-2, and GCG mRNA expression in adenovirus-CMV-GFP or adenovirus-CMV-SMOC1-GFP transduced-human islet cells from adult human non-diabetic donors by qPCR (n = 8 different human islet donors). j T2D α-cell and β-cell scores based on the expression of T2D genes in adenovirus-CMV-GFP or adenovirus-CMV-SMOC1-GFP transduced-human islet cells from adult human non-diabetic donors by qPCR and calculated as indicated in Methods. (n= 8 different human islet donors). In all the panels, bars indicate mean+ SEM; *p < 0.05 and **p < 0.01 or as indicated in the figure, using two-tailed Student’s t-test.