Flavored e-liquids increase cytoplasmic Ca2+ levels in airway epithelia.

Introduction:
This article discusses the effects of electronic cigarette (e-cigarette) flavored e-liquids on cellular Ca2+ homeostasis. The study found that many e-liquids can elicit Ca2+ responses, with Banana Pudding (BP) e-liquid causing phospholipase C activation, endoplasmic reticulum (ER) Ca2+ release, store-operated Ca2+ entry (SOCE), and protein kinase C (PKC) phosphorylation. Longer exposures to BP e-liquid can deplete ER Ca2+ stores and inhibit SOCE, suggesting that this e-liquid may alter Ca2+ homeostasis through short- and long-term mechanisms. The study emphasizes the importance of further screening flavored e-cigarette products for potential toxicity.

Key Points:

* The study used high-throughput screening approaches to investigate the effects of 224 e-liquids on Ca2+ signaling in human bronchial epithelial cells (hBECs) and CaLU3 cells.
* The authors identified 42 flavored e-liquids that elicited a Ca2+ response.
* BP e-liquid was chosen for further investigation and was found to cause phospholipase C activation, ER Ca2+ release, SOCE, and PKC phosphorylation.
* Longer exposures to BP e-liquid depleted ER Ca2+ stores and inhibited SOCE.
* The authors suggest that inappropriate activation of Ca2+ signaling pathways can have profound effects on cell function and survival.
* The study highlights the need for further investigation into the potential toxicity of flavored e-cigarette products.

Main Message:
This study underscores the importance of understanding the effects of e-cigarette flavored e-liquids on cellular Ca2+ homeostasis, a universal cell-signaling pathway that can modulate cell growth and survival. The findings suggest that certain e-liquids may have the potential to alter Ca2+ homeostasis, which can have profound effects on cell function and survival. Therefore, it is crucial to further screen flavored e-cigarette products for potential toxicity to ensure the safety of e-cigarette users.

Rowell TR, Keating JE, Zorn BT, Glish GL, Shears SB, Tarran R. Flavored e-liquids increase cytoplasmic Ca2+ levels in airway epithelia. american journal of physiology Lung cellular and molecular physiology. 2020;318(2):L226-L241. doi:10.1152/ajplung.00123.2019