Stable over-expression of the human malate–aspartate NADH shuttle member Aralar I in PK15 cells improves energy metabolism and enhances proliferation of porcine circovirus-2

Abstract

The considerable losses sustained by the pig industry due to porcine circovirus-2 (PCV2) could be avoided by using an attenuated vaccine. However, production of an attenuated PCV2 vaccine has not been satisfactory. Recently, we over-expressed the human malate–aspartate NADH shuttle member Aralar I in PK15 cells to enhance proliferation of PCV2. Compared with control PK15 cells, lactate accumulation in Aralar I over-expressing cells decreased by 44.8% (p < 0.01), whereas the mitochondrial NADH and pyruvate concentrations increased by 50% (p < 0.05) and 35.4% (p < 0.05), respectively. The ATP/ADP ratio and O₂ uptake rate also increased by 39% (p < 0.05) and 37.8% (p < 0.01), respectively. Furthermore, the glutamine consumption rate increased by 36.4% (p < 0.01). Finally, compared with the PCV2 yield of infected control PK15 cells, the PCV2 yield of infected Aralar I over-expression cells was enhanced by 42.5% (p < 0.05). These results revealed that over-expression of Aralar I can improve the energy metabolism of PK15 cells and also enhance the replication of the PCV2 virus in PK15 cells. This study presents a method to improve energy metabolism and provides a valuable thinking to enhance virus vaccine production.