Dihydroxyacetone Exposure Alters NAD(P)H and Induces Mitochondrial Stress and Autophagy in HEK293T Cells

Abstract

Dihydroxyacetone phosphate (DHAP) is the endogenous byproduct of fructose metabolism. Excess DHAP in cells can induce advanced glycation end products and oxidative stress. Dihydroxyacetone (DHA) is the triose precursor to DHAP. DHA is used as the active ingredient in sunless tanning products, including aerosolized spray tans, and is formed by the combustion of solvents found in electronic cigarettes. Human exposure to DHA has been increasing as the popularity of sunless tanning products and electronic cigarettes has grown. Topically applied DHA is absorbed through the viable layers of the skin and into the bloodstream. Exogenous exposure to DHA is cytotoxic in immortalized keratinocytes and melanoma cells with cell cycle arrest induced within 24 h and cell death occurring by apoptosis at consumer-relevant concentrations of DHA within 72 h. Less is known about systemic exposures to DHA that occur following absorption through skin, and now through inhalation of the aerosolized DHA used in spray tanning. In the present study, HEK293T cells were exposed to consumer-relevant concentrations of DHA to examine the cytotoxicity of systemic exposures. HEK293T cells were sensitive to consumerrelevant doses of DHA with an IC 50 value of 2.4 ± 0.3 mM. However, cell cycle arrest did not begin until 48 h after DHA exposure. DHA-exposed cells showed altered metabolic activity with decreased mitochondrial function and decreased lactate and ATP production observed within 24 h of exposure. Autofluorescent imaging and NAD + sensors also revealed an imbalance in the redox cofactors NAD + /NADH within 24 h of exposure. Cell death occurred by autophagy indicated by increases in LC3B and SIRT1. Despite DHA's ability to be converted to DHAP and integrated into metabolic pathways, the metabolic dysfunction and starvation responses observed in the HEK293T cells indicate that DHA does not readily contribute to the energetic pool in these cells.

Application of High-Resolution Mass Spectrometry and a Theoretical Model to the Quantification of Multifunctional Carbonyls and Organic Acids in e-Cigarette Aerosol

“…93 Although hydroxycarbonyls are abundant in e-cigarette aerosols, a general lack of toxicological data precludes health risk assessment. Smith et al 94 found that exogenous exposure to dihydroxyacetone is cytotoxic and will cause cell death by apoptosis. Glycolaldehyde is also suspected to have biological toxicity.…”

Vaping Cardiovascular Health Risks: an Updated Umbrella Review

“…Several avenues for research are worth exploring. For instance, translational studies on the precise cellular mechanisms involved in EVC toxicity are needed, exploring for instance microRNA, inflammatory cascade, autophagy, apoptosis, and regeneration [36][37][38]. Observational studies on large samples are needed to accurately gauge the short and long-term risks of EVC in apparently healthy subjects and in patients with cardiovascular disease [39].…”

Dihydronicotinamide riboside promotes cell-specific cytotoxicity by tipping the balance between metabolic regulation and oxidative stress

“…NAD(P)H levels were measured using the endogenous autofluorescence of these dinucleotides when they are excited with a 355 nm laser, as described in [ 34 ]. Briefly, HEK293T and HepG3 cells were seeded in an 8-well chambered coverglass at a density of 2 X 10 4 cells/chamber and 4 X 10 4 cells/chamber, respectively and incubated ON at 37°C in a 5% CO 2 incubator.…”