Bafilomycin A1 (Synonyms: NSC 381866)

Cell lines

Eosinophils

Preparation Method

Circulating eosinophils were purified from donors with eosinophils >35 per μL of blood. Eosinophil preparations with purity >98% and viability ~98% were used.

Reaction Conditions

Eosinophils were cultured at 1 × 106/mL in complete medium (RPMI 1640 plus 10% fetal bovine serum) with IL3 (2 ng/mL) or IL5 (2 ng/mL) both cytokines from BD Biosciences for 20 h, and were then washed and cultured with complete medium (no IL3 or IL5) on coated heat-aggregated immunoglobulins-G (HA-IgG or IgG) or without IgG as previously described.

Applications

Bafilomycin-A1 could be used to show the impact of autophagolysosome formation on eosinophil cytolysis. Treated IL3- and IL5-primed eosinophils with bafilomycin-A1 before interaction with IgG, and then measured cytolysis using rhodamine-110 (R110). Treatment with bafilomycin-A1 increased IL3-primed and IL5-primed eosinophil lysis by 50% and 100%, respectively, suggesting that autophagolysosome formation protects from cytolysis for both IL3- and IL5-primed eosinophils.

Animal models

Lck-mTOR + CLP mice, WT + CLP mice, Lck-TSC1 mice

Preparation Method

Crossed TSC1loxp/loxp and mTORloxp/loxp mice with Lck-Cre mice (Cre expression under the control of lymphocyte-specific protein tyrosine kinase, Lck) to obtain the F1 generation Lck-Cre:mTORloxp/− mice and Lck-Cre:TSC1loxp/− mice, respectively. We interbred F1 generation mice in each group and obtained F2 generation Lck-Cre: mTORloxp/loxp and Lck-Cre;TSC1loxp/loxp mice. Littermates lacking Lck-Cre served as controls. Then mice were anesthetized, and the abdomen was opened surgically and the cecum was ligated halfway between the distal pole and the base. The cecal stump was punctured once with a 22-gauge needle. Put back the cecum and closed the abdomen. Administered 1 mL saline subcutaneously to each animal for fluid resuscitation. Animals in the sham group underwent the same surgical procedure without ligation or puncture. Bafilomycin A1 was administered intraperitoneally 1 h after the CLP operation.

Dosage form

1 mg/kg

Applications

Bafilomycin A1 could specifically block fusion of autophagosomes and lysosomes and attenuate the protective effects of mTOR deletion against CD4 + T cell apoptosis. In Lck-mTOR + CLP mice treated with bafilomycin A1, the apoptosis rate of CD4 + T cells was higher compared with mice that did not receive bafilomycin A1 and lower compared with mice in WT + CLP + bafilomycin A1 group.

References:

[1]. Esnault S, et al. IL-3 up-regulates and activates human eosinophil CD32 and αMβ2 integrin causing degranulation. Clin Exp Allergy. 2017 Apr;47(4):488-498.

[2]. Esnault S, et al. Autophagy Protects against Eosinophil Cytolysis and Release of DNA. Cells. 2022 Jun 2;11(11):1821.

[3]. Wang H, et al. mTOR deletion ameliorates CD4 + T cell apoptosis during sepsis by improving autophagosome-lysosome fusion. Apoptosis. 2022 Jun;27(5-6):401-408.