Adrenomedullin protects Leydig cells against lipopolysaccharide-induced oxidative stress and inflammatory reaction via MAPK/NF-κB signalling pathways

Abstract

This study aimed to explore the possible benefits of adrenomedullin (ADM) in preventing oxidative stress and inflammation by using an in vitro primary culture model of rat Leydig cells exposed to lipopolysaccharide (LPS). Cell proliferation was detected through CCK-8 and BrdU incorporation assays. ROS were determined with a DCFDA kit, and cytokine concentrations were measured with ELISA assay kits. Protein production was examined by immunohistochemical staining and Western blot, and gene expression was observed through RT-qPCR. Results revealed that ADM significantly reduced LPS-induced cytotoxicity, and pretreatment with ADM significantly suppressed ROS overproduction and decreased 4-HNE and 8-OHdG expression levels and concentrations. ADM pretreatment also significantly attenuated the overactivation of enzymatic antioxidants, namely, superoxide dismutase, catalase, thioredoxin reductase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase. ADM supplementation reversed the significantly increased gene expression levels and concentrations of TNF-α, IL-1β, TGF-β1, MCP-1 and MIF. ADM pretreatment significantly inhibited the gene expression and protein production of TLR-2 and 4. Furthermore, ADM pretreatment markedly reduced the phosphorylation of JNK, ERK 1/2 and p38, phosphorylation and degradation of IκBα and nuclear translocation of p65. Our findings demonstrated that ADM protects Leydig cells from LPS-induced oxidative stress and inflammation, which might be associated with MAPK/NF-κB signalling pathways.

Macrophage migration inhibitory factor (MIF) inhibitor 4‐IPP suppresses osteoclast formation and promotes osteoblast differentiation through the inhibition of the NF‐κB signaling pathway

“…Binding of MIF to CD74 induces its phosphorylation and the recruitment of CD44, which then activates Src tyrosine kinase, leading to ERK1/2 phosphorylation and sustained activation of the ERK-MAPK pathway. The downstream consequences of this include NF-kB nuclear translocation, up-regulation of phospholipase A2 and prostaglandins, and the stimulation of the arachidonic acid pathway (9)(10)(11)(12). CD74-CD44 activation also induces PI3K/PKB signaling, promoting cellular growth and initiate the p53dependent inhibition of apoptosis (13,14).…”

Systematic Analysis of Gene Expression Alteration and Co-Expression Network of Eukaryotic Initiation Factor 4A-3 in Cancer

“…Growing evidence supports a major role of NF-κB in oncogenesis as it regulates genes involved in the development and progression of cancer, such as proliferation, migration, apoptosis, drug resistance, and angiogenesis23-27. The TNF-α/NF-κB signaling pathway cross-talks with the MAPK pathway, Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway, and mitochondrial apoptosis pathway regulated by bcl-2 family proteins28-30. Thus, the TNF-α/NF-κB signaling pathway is a key signaling pathway that affects multiple phenotypes of cancer and is a potential target for cancer therapy.…”

HIF1α/miR-199a/ADM feedback loop modulates the proliferation of human dermal microvascular endothelial cells (HDMECs) under hypoxic condition

“…ADM pretreatment can markedly reduce the nuclear translocation of p65, therefore decreasing the significantly increased gene expression levels and concentrations of cytokines [26]. Here, the dynamic effects of HIF1A knockdown and ADM overexpression on p65 nuclear translocation and cytokine release were evaluated under hypoxia.…”