Fig. 1: PITPNA expression is decreased in isolated islets of T2D human subjects.

a Immunostaining of endogenous INSULIN (cyan), PITPNA (green), and protein markers (magenta) for the Golgi (GIANTIN), ER (CALR), and intracellular granules (CD63) in pancreatic islets isolated from a non-diabetic human subject. White arrows denote the colocalization of protein markers with PITPNA. b UMAP projection and graph-based clustering of scRNA-Seq analysis performed on isolated human pancreatic islet cell types. c Relative abundance of PITPNA in islet cell clusters from human donors. d Comparison of PITPNA expression in islet endocrine cell types from T2D (green) and non-diabetic donors (red). e Normalized PITPNA expression from bulk RNA sequencing of isolated human islets across non-diabetic (n = 51), pre-diabetic (n = 27), and diabetic human subjects (n = 11). Normalized expression values are shown in reads per million (RPM). P_{Non vs Pre-diabetes} = 0.7248, P_{Non vs Diabetes} = 0.025, P_{Diabetes vs Pre-diabetes} = 0.1278, f Correlation analysis between normalized islet PITPNA expression and HbA1c of human subjects (n = 77). The R2 value indicates the correlation coefficient. g Correlation analysis between normalized islet PITPNA expression and body mass index (BMI) of human subjects (n = 89). The R2 value indicates the correlation coefficient. h qRT-PCR analysis of PITPNA mRNA expression in pancreatic islets isolated from non-diabetic (n = 15) and T2D (n = 5) human donors. P = 0.0006. Error bar: ND = 1.00 ± 0.02, T2D = 0.43 ± 0.04. i Western blot analysis of PITPNA and AGO2 expression in isolated islets of non-diabetic human donors (ND) and T2D donors (T2D). Data are presented as mean values ± SEM for (e), (h). *P < 0.05, ***P < 0.001. Ordinary one-way ANOVA with Turkey’s multiple comparisons test was used for (e). Linear regression was used for (f), (g). Two-tailed unpaired Student t-test were used for (h). All primary source data are reported in the Source data file.