The effects of Tissue-type Plasminogen Activator on PSC Activation.

Abstract

Objective: Our previous studies have demonstrated that the activated pancreatic stellate cell (PSC) could induce islet damage in type 2 diabetes mellitus (T2DM). While tissue-type plasminogen activator (tPA) is significantly reduced in T2DM, its subsequent effects are unclear. The purpose of this experiment was to observe the impact of tPA on PSC activation, with the aim to better understand the potential role of tPA in T2DM.

Methods: 50 type 2 diabetic patients and 50 healthy persons were included in the diabetic group and the control group, respectively. Fasting blood was collected separately, and the tPA-level was detected by ELISA. Rat PSCs were isolated from pancreatic tissue using standard explant techniques. The PSCs were then characterized by staining them with Oil Red O to visualize lipid droplets and using immunofluorescent markers (α-smooth muscle actin (α-SMA), vimentin, and glial fibrillary acidic protein (GFAP)). After characterization, the PSCs were treated with tPA, then the proliferation of PSCs was measured using the cell counting kit-8 (CCK-8), the apoptosis was observed by the caspase-3 fluorometric assay kit, and the migration ability was assessed using the wound-healing assay and the transwell migration assay. Finally, a Western blot was used to identify the extracellular matrix (ECM) component synthesized by PSCs.

Results: The diabetic patients had significantly lower levels of tPA compared to the controls. Rat PSCs treated with tPA exhibited more lipid droplet accumulation, and their ability of proliferation, migration, and ECM synthesis were significantly inhibited.

Conclusion: This study demonstrated that tPA can play a crucial role in significantly inhibiting the activation, proliferation, migration, and ECM synthesis of PSC. Therefore, we speculate that the significant reduction of tPA in T2DM may exacerbate the detrimental effect of PSC on β-cell function.