Rh-relaxin-2 attenuates degranulation of mast cells by inhibiting NF-κB through PI3K-AKT/TNFAIP3 pathway in an experimental germinal matrix hemorrhage rat model

Abstract

Background: Mast cells play an important role in early immune reactions in the brain by degranulation and the consequent inflammatory response. Our aim of the study is to investigate the effects of rh-relaxin-2 on mast cells and the underlying mechanisms in a germinal matrix hemorrhage (GMH) rat model. Methods: One hundred seventy-three P7 rat pups were subjected to GMH by an intraparenchymal injection of bacterial collagenase. Clodronate liposome was administered through intracerebroventricular (i.c.v.) injections 24 h prior to GMH to inhibit microglia. Rh-relaxin-2 was administered intraperitoneally at 1 h and 13 h after GMH. Small interfering RNA of RXFP1 and PI3K inhibitor LY294002 were given by i.c.v. injection. Post-GMH evaluation included neurobehavioral function, Western blot analysis, immunofluorescence, Nissl staining, and toluidine blue staining. Results: Our results demonstrated that endogenous relaxin-2 was downregulated and that RXFP1 level peaked on the first day after GMH. Administration of rh-relaxin-2 improved neurological functions, attenuated degranulation of mast cells and neuroinflammation, and ameliorated post-hemorrhagic hydrocephalus (PHH) after GMH. These effects were associated with RXFP1 activation, increased expression of PI3K, phosphorylated AKT and TNFAIP3, and decreased levels of phosphorylated NF-κB, tryptase, chymase, IL-6, and TNF-α. However, knockdown of RXFP1 and PI3K inhibition abolished the protective effects of rh-relaxin-2. Conclusions: Our findings showed that rh-relaxin-2 attenuated degranulation of mast cells and neuroinflammation, improved neurological outcomes, and ameliorated hydrocephalus after GMH through RXFP1/PI3K-AKT/TNFAIP3/NF-κB signaling pathway.

Evaluation of pharmacological activities and active components in Tremella aurantialba by instrumental and virtual analyses

“…Many of the effects of human gene-2 relaxin (H2 relaxin) are mediated by its homologous G protein-coupled receptor (GPCR) and relaxin family peptide receptor (RXFP1). For example, the activation of RXFP1 by rh-RLN2 can improve mast cell degranulation and neurological function by inhibiting NF-κB of PI3K-AKT/neoplasm necrosis factor-alpha-induced protein 3 (TNFAIP3) signaling pathway, which indicated that rh-RLN2 may be a promising therapeutic agent to reduce neuroinflammation and secondary brain injury in germinal matrix hemorrhage patients ( 39 ). RLN-2 produces endothelium- and NO-dependent relaxation of mouse mesenteric arteries by activation of RXFP1 coupled to Gi2-PI3K-eNOS pathway.…”

Effects of Upregulation of TNFAIP3 on Diabetic Neuropathic Pain in Mice

“…It is both deubiquitinating and is an ubiquitin ligase. The vital involvement of this protein in regulating inflammatory signal transduction [ 15 , 16 ] to negatively regulate the NF- κ B pathway via feedback and inhibit NF- κ B pathway activation via several inflammatory signals has been shown [ 17 – 20 ]. It can inhibit the transcription of downstream inflammatory factors and has a strong anti-inflammatory effect.…”

Relaxin Affects Airway Remodeling Genes Expression through Various Signal Pathways Connected with Transcription Factors

“…Silencer siRNA Transfection Kit (Thermo Fisher Scientific, Waltham, MA, USA) was used for the knockdown of selected genes (NF-κB, c-Myc and STAT3), according to the manufacturer’s instructions ( Figure S1 ). The transcription factors were selected according to the literature, as the factors involved in the process of airway remodeling, but also as suggested elements of the relaxin pathway in this process [ 23 , 101 , 102 , 103 , 104 , 105 ]. The cells were treated with 20 nM siRNA mixture against NF-κB (NCBI accession no.…”