Effects of angiotensin II receptor antagonist, Losartan on the apoptosis, proliferation and migration of the human pancreatic stellate cells - PubMed (original) (raw)

Effects of angiotensin II receptor antagonist, Losartan on the apoptosis, proliferation and migration of the human pancreatic stellate cells

Wen-Bin Liu et al. World J Gastroenterol. 2005.

Abstract

Aim: To investigate the effects of AT1 (Type 1 angiotensin II receptor) antagonist (Losartan) on the apoptosis, proliferation and migration of the human pancreatic stellate cells (hPSCs).

Methods: hPSCs were isolated from pancreatic sample of patients with pancreatic carcinoma using radioimmunoassay (RIA) technique to detect the concentration of AngII in culture media and cell homogenate. Immunocytochemistry (ICC) and in situ hybridization (ISH) methods were utilized to test AT1 expression in hPSCs. Effects of Losartan on hPSCs proliferation, apoptosis and migration were investigated using BrdU incorporation, TUNEL, flow cytometry (FCM), and phase-contrast microscope separately when cells treated with Losartan. Immunofluorescence and Western blot were applied to quantify the expression of type I collagen in hPSCs.

Results: There exists AT1 expression in hPSCs, while no AngII was detected in culture media and cell homogenate. Losartan induces cell apoptosis in a dose- and time-dependent manner (apparently at 10(-5) mol/L), no pro-proliferative effect was observed in the same condition. Corresponding dosage of Losartan can also alleviate the motion capability and type I collagen content of hPSCs compared with AngII treatment and non-treatment control groups.

Conclusion: These findings suggest that paracrine not autocrine functions of AngII may have effects on hPSCs, which was mediated by AT1 expressed on cells, while Losartan may exert anti-fibrotic effects by inhibiting hPSCs motion and partly by inducing apoptosis.

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Figures

Figure 1

Figure 1

Immunocytochemistry and ISH detection of AT1 in hPSCs at protein and mRNA levels. Immunostaining positive particles were located in plasm, A (magnification ×100); B (magnification ×400). ISH positive signals were located in nuclei C (magnification ×100); D (magnification ×400).

Figure 2

Figure 2

Dose-dependent induction of apoptosis by Losartan at different concentrations. (Con, 1 = 10-9, 2 = 10-7 , 3 = 10-5, 4 = 10-3 mol/L; a_P_ < 0.05 vs different from all groups ).

Figure 3

Figure 3

Time-course of Losartan-induced apoptosis. hPSCs in 0.1% FCS were exposed to 10-5 mol/L Losartan, and was assessd at 24, 48,72 h. Results indicate that Losartan induces apoptosis in a time-dependent manner.

Figure 4

Figure 4

Effects of Losartan on hPSCs proliferation assessed with BrdU incorporation. Losartan itself did not affect cell proliferation compared to control group. (a_P_>0.05 different from all the groups).

Figure 5

Figure 5

AngII accelerates in vitro wound healing confluent, culture-activated PSCs were serum deprived for 48 h. A wound was produced in the monolayer with a pipette tip, and the cells were exposed to (A) AngII (10-8 mol/L), (B) 10% fetal bovine serum, (C) AngII + Losartan, (D) serum-free medium along 24 h later, the cells were photographed.

Figure 6

Figure 6

Losartan down-regulated collagen I protein expression by western blot and immunofluoresence. hPSCs were incubated with 10-6 mol/L Losartan. Samples were exposed to certain concentration of Losartan+AngII and AngII for 24 h.

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