Effect of deferoxamine and ferrostatin-1 on salivary gland dysfunction in ovariectomized rats

The Hydroxypyridinone Iron Chelator DIBI Reduces Bacterial Load and Inflammation in Experimental Lung Infection

Iron plays a critical role in lung infections due to its function in the inflammatory immune response but also as an important factor for bacterial growth. Iron chelation represents a potential therapeutic approach to inhibit bacterial growth and pathologically increased pro-inflammatory mediator production. The present study was designed to investigate the impact of the iron chelator DIBI in murine lung infection induced by intratracheal Pseudomonas aeruginosa (strain PA14) administration. DIBI is a polymer with a polyvinylpyrrolidone backbone containing nine 3-hydroxy-1-(methacrylamidoethyl)-2-methyl-4(1H) pyridinone (MAHMP) residues per molecule and was given by intraperitoneal injection either as a single dose (80 mg/kg) immediately after PA14 administration or a double dose (second dose 4 h after PA14 administration). The results showed that lung NF-κBp65 levels, as well as levels of various inflammatory cytokines (TNFα, IL-1β, IL-6) both in lung tissue and bronchoalveolar lavage fluid (BALF), were significantly increased 24 h after PA14 administration. Single-dose DIBI did not affect the bacterial load or inflammatory response in the lungs or BALF. However, two doses of DIBI significantly decreased bacterial load, attenuated NF-κBp65 upregulation, reduced inflammatory cytokines production, and relieved lung tissue damage. Our findings support the conclusion that the iron chelator, DIBI, can reduce lung injury induced by P. aeruginosa, via its anti-bacterial and anti-inflammatory effects.

Downregulated GPX4 in salivary gland epithelial cells contributes to salivary secretion dysfunction in Sjogren's syndrome via lipid ROS/pSTAT4/AQP5 axis

Sjogren's syndrome (SS) is an autoimmune disease characterized by dysfunction of exocrine glands, such as salivary glands. However, the molecular mechanism of salivary secretion dysfunction in SS is still unclear. Given the significance of glutathione peroxidase 4 (GPX4) in cellular redox homeostasis, we hypothesized that dysregulation of GPX4 may play a pivotal role in the pathogenesis of salivary secretion dysfunction observed in SS. The salivary gland of SS patients and the SS mouse model exhibited reduced expression of the ferroptosis inhibitor GPX4 and the important protein aquaporin 5 (AQP5), which is involved in salivary secretion. GPX4 overexpression upregulated and GPX4 knockdown downregulated AQP5 expression in salivary gland epithelial cells (SGECs) and salivary secretion. Bioinformatics analysis of GSE databases from SS patients' salivary glands revealed STAT4 as a key intermediary regulator between GPX4 and AQP5. A higher level of nuclear pSTAT4 was observed in the salivary gland of the SS mouse model. GPX4 overexpression inhibited and GPX4 knockdown promoted STAT4 phosphorylation and nuclear translocation in SGECs. CHIP assay confirmed the binding of pSTAT4 within the promoter of AQP5 inhibiting AQP5 transcription. GPX4 downregulation accumulates intracellular lipid ROS in SGECs. Lipid ROS inhibitor ferrostatin-1 treatment during in vitro and in vivo studies confirmed that lipid ROS activates STAT4 phosphorylation and nuclear translocation in SGECs. In summary, the downregulated GPX4 in SGECs contributes to salivary secretion dysfunction in SS via the lipid ROS/pSTAT4/AQP5 axis. This study unraveled novel targets to revitalize the salivary secretion function in SS patients.

Ferroptosis in organ fibrosis: From mechanisms to therapeutic medicines

Fibrosis occurs in many organs, and its sustained progress can lead to organ destruction and malfunction. Although numerous studies on organ fibrosis have been carried out, its underlying mechanism is largely unknown, and no ideal treatment is currently available. Ferroptosis is an iron-dependent process of programmed cell death that is characterized by lipid peroxidation. In the past decade, a growing body of evidence demonstrated the association between ferroptosis and fibrotic diseases, while targeting ferroptosis may serve as a potential therapeutic strategy. This review highlights recent advances in the crosstalk between ferroptosis and organ fibrosis, and discusses ferroptosis-targeted therapeutic approaches against fibrosis that are currently being explored.

Modes and Mechanisms of Salivary Gland Epithelial Cell Death in Sjogren's Syndrome

Sjogren's syndrome is an autoimmune disease in middle and old-aged women with a dry mucosal surface, which is caused by the dysfunction of secretory glands, such as the oral cavity, eyeballs, and pharynx. Pathologically, Sjogren's syndrome are characterized by lymphocyte infiltration into the exocrine glands and epithelial cell destruction caused by autoantibodies Ro/SSA and La/SSB. At present, the exact pathogenesis of Sjogren's syndrome is unclear. Evidence suggests epithelial cell death and the subsequent dysfunction of salivary glands as the main causes of xerostomia. This review summarizes the modes of salivary gland epithelial cell death and their role in Sjogren's syndrome progression. The molecular mechanisms involved in salivary gland epithelial cell death during Sjogren's syndrome as potential leads to treating the disease are also discussed.