[Pancreatic β-cell dedifferentiation detected by flow cytometry]

Objective: To establish a method for detecting pancreatic β-cell dedifferentiation using flow cytometry. Methods: Experimental study. Min6 (mouse β cell line), αTC1-6 (mouse α cell line), HepG2 (human hepatocellular carcinoma cells) and mouse F9 cells (mouse teratocarcinoma cell) were cultured with conventional medium. Min6 cells were treated with interleukin-1β (IL-1β) in combined with tumor necrosis factor α (TNFα), or palmitic acid (PA) overnight and stained with anti-chromogranin A (ChgA), anti-insulin (Ins), anti-glucagon (Gcg), anti-SRY-box transcription factor 9 (Sox9) and anti-octamer binding transcription factor 4 (Oct4) antibodies, respectively. Flow cytometry was applied to detect the pression of ChgA, Ins, Gcg, Sox9, and Oct4 in the cells, respectively. Unpaired Student t test was used for statistical analysis. Results: Flow cytometry analyses showed that Ins and ChgA were highly expressed in Min6 cells, Gcg was highly expressed in αTC1-6, Sox9 was highly expressed in HepG2, and Oct4 was highly expressed in F9 cells, respectively (around 90%). Treatment of Min6 cells with IL-1β+TNFα significantly decreased Ins positive staining cells (92.775%±1.702% vs. 97.125%±0.246%, P=0.045), while increased Sox9 positive staining cells (41.675%±0.390% vs. 25.875%±3.348%, P=0.003). No significant changes in ChgA and Oct4 expression could be viewed (both P>0.05). PA treatment elevated the number of Gcg positive staining cells (54.500%±3.597% vs. 41.160%±3.007%, P=0.022). The levels of mRNA expression by qPCR of the above proteins were in consistent with the levels of protein expression by flow cytometry in Min6 cells. Conclusion: Flow cytometry can be used to detect proteins expressed in dedifferentiated models of β cells, which provides a new method for identify dedifferentiation of pancreatic β cells.