mtDNA amplifies beryllium sulfate-induced inflammatory responses via the cGAS-STING pathway in 16HBE cells.

Beryllium sulfate (BeSO4) can cause inflammation through the mechanism, which has not been elucidated. Mitochondrial DNA (mtDNA) is a key contributor of inflammation. With mitochondrial damage, released mtDNA can bind to specific receptors (e.g., cGAS) and then activate related pathway to promote inflammatory responses. To investigate the mechanism of mtDNA in BeSO4-induced inflammatory response in 16HBE cells, we established the BeSO4-induced 16HBE cell inflammation model and the ethidium bromide (EB)-induced ρ016HBE cell model to detect the mtDNA content, oxidative stress-related markers, mitochondrial membrane potential, the expression of the cGAS-STING pathway, and inflammation-related factors. Our results showed that BeSO4 caused oxidative stress, decline of mitochondrial membrane potential, and the release of mtDNA into the cytoplasm of 16HBE cells. In addition, BeSO4 induced inflammation in 16HBE cells by activating the cGAS-STING pathway. Furthermore, mtDNA deletion inhibited the expression of cGAS-STING pathway, IL-10, TNF-α, and IFN-ß. This study revealed a novel mechanism of BeSO4-induced inflammation in 16HBE cells, which contributes to the understanding of the molecular mechanism of beryllium and its compounds-induced toxicity.

Hsa_circ_0004214 involved in the epithelial-mesenchymal transition induced by beryllium sulfate through modulating JAK-STAT signaling pathway.

Background: Chronic beryllium disease is characterized by granulomas and pulmonary fibrosis. Recent studies have shown that microRNAs (miRNAs) and circular RNAs (circRNAs) play critical roles in the pathogenesis and development of many diseases. However, the role of miRNAs and circRNAs in pulmonary fibrosis induced by beryllium sulfate (BeSO4) has not been elucidated. Methods: Previous studies demonstrated hsa-miR-663b was down-regulated in the 150 µmol/L BeSO4-treated 16HBE cells, while hsa_circ_ 0004214 was up-regulated. Here we found epithelial-mesenchymal transition (EMT) involved in pulmonary fibrosis induced by BeSO4 (4, 8, and 12 mg/kg·BW) in SD rats. Results: Elevated expression of hsa-miR-663b blocked the EMT progression of 16HBE cells induced by 150 µmol/L BeSO4. Notably, the overexpression of hsa-miR-663b decreased the expression of leukemia inhibitory factor (LIF), which was predicted as a target gene of hsa-miR-663b by bioinformatics tools. Furthermore, elevated miR-663b inhibited the activation of the downstream Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway induced by BeSO4 in 16HBE cells. Previous study suggested that hsa_circ_0004214 had binding sites for hsa-miR-663b. The results indicated hsa_circ_0004214 alleviated the BeSO4-induced EMT via JAK-STAT pathway in 16HBE cells. Conclusions: Collectively, the overexpression of hsa-miR-663b and knockdown of hsa_circ_0004214 attenuated the EMT induced by BeSO4 through the inhibition of JAK-STAT signaling pathway. The aberrant expressed hsa-miR-663b and hsa_circ_0004214 stimulated by BeSO4 may exert an important function in the toxic mechanism of beryllium exposure to 16HBE cells, providing the potential therapeutic targets in chronic beryllium disease.

Hydrogen sulfide alleviates beryllium sulfate-induced ferroptosis and ferritinophagy in 16HBE cells.

Beryllium sulfate (BeSO4 ) can result to lung injuries, such as leading to lipid peroxidation and autophagy, and the treatment of beryllium disease has not been well improved. Ferroptosis is a regulated cell death process driven by iron-dependent and lipid peroxidation, while ferritinophagy is a process mediated by nuclear receptor coactivator 4 (NCOA4), combined with ferritin heavy chain 1 (FTH1) degradation and release Fe2+ , which regulated intracellular iron metabolism and ferroptosis. Hydrogen sulfide (H2 S) has the effects of antioxidant, antiautophagy, and antiferroptosis. This study aimed to investigate the effect of H2 S on BeSO4 -induced ferroptosis and ferritinophagy in 16HBE cells and the underlying mechanism. In this study, BeSO4 -induced 16HBE cell injury model was established based on cellular level and pretreated with deferoxamine (DFO, a ferroptosis inhibitor), sodium hydrosulfide (NaHS, a H2 S donor), or NCOA4 siRNA and, subsequently, performed to detect the levels of lipid peroxidation and Fe2+ and the biomarkers of ferroptosis and ferritinophagy. More importantly, our research found that DFO, NaHS, or NCOA4 siRNA alleviated BeSO4 -induced ferroptosis and ferritinophagy by decreasing the accumulation of Fe2+ and lipid peroxides. Furthermore, the relationship between ferroptosis, ferritinophagy, H2 S, and beryllium disease is not well defined; therefore, our research is innovative. Overall, our results provided a new theoretical basis for the prevention and treatment of beryllium disease and suggested that the application of H2 S, blocking ferroptosis, and ferritinophagy may be a potential therapeutic direction for the prevention and treatment of beryllium disease.