The NOX2-mediated ROS producing capacity of recipient cells is associated with reduced T cell infiltrate in an experimental model of chronic renal allograft inflammation

Thymol mitigates lipopolysaccharide-induced endometritis by regulating the TLR4- and ROS-mediated NF-κB signaling pathways

The purpose of this study was to investigate the effects of thymol on lipopolysaccharide (LPS)-induced inflammatory responses and to clarify the potential mechanism of these effects. LPS-induced mouse endometritis was used to confirm the anti-inflammatory action of thymol in vivo. RAW264.7 cells were used to examine the molecular mechanism and targets of thymol in vitro. In vivo, thymol markedly alleviated LPS-induced pathological injury, myeloperoxidase (MPO) activity, and the production of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in mice. Further studies were performed to examine the expression of the Toll-like receptor 4 (TLR4) -mediated nuclear factor-κB (NF-κB) pathway. These results showed that the expression of the TLR4-mediated NF-κB pathway was inhibited by thymol treatment. In vitro, we observed that thymol dose-dependently inhibited the expression of TNF-α, IL-1β, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW264.7 cells. Moreover, the results obtained from immunofluorescence assays also indicated that thymol dose-dependently suppressed LPS-induced reactive oxygen species (ROS) production. Silencing of TLR4 inhibited NF-κB pathway activation. Furthermore, H₂O₂ treatment increased the phosphorylation of p65 and IκBα, which were decreased when treated with N-acetyl cysteine or thymol. In conclusion, the anti-inflammatory effects of thymol are associated with activation of the TLR4 or ROS signaling pathways, contributing to NF-κB activation, thereby alleviating LPS-induced oxidative and inflammatory responses.

Nox and renal disease

Since the first demonstration of Nox enzyme expression in the kidney in the early 1990s and the subsequent identification of Nox4, or RENOX, a decade later, it has become apparent that the Nox family of reactive oxygen species (ROS) generating enzymes plays an integral role in the normal physiological function of the kidney. As our knowledge of Nox expression patterns and functions in various structures and specialized cell types within the kidney grows, so does the realization that Nox-derived oxidative stress contributes significantly to a wide variety of renal pathologies through their ability to modify lipids and proteins, damage DNA and activate transcriptional programmes. Diverse studies demonstrate key roles for Nox-derived ROS in kidney fibrosis, particularly in settings of chronic renal disease such as diabetic nephropathy. As the most abundant Nox family member in the kidney, much emphasis has been placed on the role of Nox4 in this setting. However, an ever growing body of work continues to uncover key roles for other Nox family members, not only in diabetic kidney disease, but in a diverse array of renal pathological conditions. The objective of the present review is to highlight the latest novel developments in renal Nox biology with an emphasis not only on diabetic nephropathy but many of the other renal disease contexts where oxidative stress is implicated.