Smoking or occupational exposure leads to low concentrations of acrolein on the surface of the airways. Acrolein is involved in the pathophysiological processes of various respiratory diseases. Reports showed that acrolein induced an increase in mitochondrial reactive oxygen species (mROS). Furthermore, exogenous H₂O₂ was found to increase intracellular Zn2⁺ concentration ([Zn2⁺]ᵢ). However, the specific impact of acrolein on changes in intracellular Zn2⁺ levels has not been fully investigated. Therefore, this study aimed to investigate the effects of acrolein on mROS and [Zn2⁺]ᵢ in A549 cells. We used Mito Tracker Red CM-H2Xros (MitoROS) and Fluozin-3 fluorescent probes to observe changes in mROS and intracellular Zn2⁺. The results revealed that acrolein increased [Zn2⁺]ᵢ in a time- and dose-dependent manner. Additionally, the production of mROS was observed in response to acrolein treatment. Subsequent experiments showed that the intracellular Zn2⁺ chelator TPEN could inhibit the acrolein-induced elevation of [Zn2⁺]ᵢ but did not affect the acrolein-induced mROS production. Conversely, the acrolein-induced elevation of mROS and [Zn2⁺]ᵢ were significantly decreased by the inhibitors of ROS formation (NaHSO₃, NAC). Furthermore, external oxygen free radicals increased both [Zn2⁺]ᵢ levels and mROS production. These results demonstrated that acrolein-induced elevation of [Zn2⁺]ᵢ in A549 cells was mediated by mROS generation, rather than through a pathway where [Zn2⁺]ᵢ elevation leads to mROS production.
The diagnostic approaches for Hermansky-Pudlak Syndrome (HPS) include genetic sequencing, immunoblotting, electron microscopy (EM), and flow cytometry with mepacrine staining. However, these methods are often impractical for routine clinical use due to high cost, technical complexity, and limited availability. In this study, we evaluated dense granules (DGs) function in HPS mouse models using flow cytometry with mepacrine and FluoZin-3 staining. We then developed a standardized, practical flow cytometry-based protocol and validated it in patients with HPS and oculocutaneous albinism (OCA), which were confirmed by whole-mount EM. In HPS mouse models (BLOC-1, BLOC-2, BLOC-3, and AP-3 deficient mutants), mepacrine uptake was consistently reduced. FluoZin-3 fluorescence showed subtype-specific zinc dysregulation, with elevated levels in BLOC-1, BLOC-2, and AP-3 mutants but decreased levels in the BLOC-3 mutant. In contrast, the OCA-6 mouse mutant showed no significant changes in either mepacrine or FluoZin-3 uptake. Similar patterns were observed in HPS and non-syndromic OCA patients. Our findings indicate that the protocol can enable the precise diagnosis and preliminary subtype classification of HPS, while also facilitating differential diagnosis between HPS and OCA. This method offers a rapid, clinically accessible alternative to conventional diagnostic techniques and may also be applicable to other storage pool disorders with DG defects.