The potential role of mast cells and fibroblast growth factor-2 in the development of hypertension-induced renal damage

Accumulation of Renal Fibrosis in Hyperuricemia Rats Is Attributed to the Recruitment of Mast Cells, Activation of the TGF-β1/Smad2/3 Pathway, and Aggravation of Oxidative Stress

Renal fibrosis is relentlessly progressive and irreversible, and a life-threatening risk. With the continuous intake of a high-purine diet, hyperuricemia has become a health risk factor in addition to hyperglycemia, hypertension, and hyperlipidemia. Hyperuricemia is also an independent risk factor for renal interstitial fibrosis. Numerous studies have reported that increased mast cells (MCs) are closely associated with kidney injury induced by different triggering factors. This study investigated the effect of MCs on renal injury in rats caused by hyperuricemia and the relationship between MCs and renal fibrosis. Our results reveal that hyperuricemia contributes to renal injury, with a significant increase in renal MCs, leading to renal fibrosis, mitochondrial structural disorders, and oxidative stress damage. The administration of the MCs membrane stabilizer, sodium cromoglycate (SCG), decreased the expression of SCF/c-kit, reduced the expression of α-SMA, MMP2, and inhibited the TGF-β1/Smad2/3 pathway, thereby alleviating renal fibrosis. Additionally, SCG reduced renal oxidative stress and mitigated mitochondrial structural damage by inhibiting Ang II production and increasing renal GSH, GSH-Px, and GR levels. Collectively, the recruitment of MCs, activation of the TGF-β1/Smad2/3 pathway, and Ang II production drive renal oxidative stress, ultimately promoting the progression of renal fibrosis in hyperuricemic rats.

GPR30-mediated non-classic estrogen pathway in mast cells participates in endometriosis pain via the production of FGF2

Pain is one of the main clinical symptoms of endometriosis, but its underlying mechanism is still not clear. Recent studies have shown that the secretory mediators of mast cells activated by estrogen are involved in the pathogenesis of endometriosis-related pain, but how estrogen-induced mast cell mediators are involved in endometriosis-related pain remains unclear. Here, mast cells were found to be increased in the ovarian endometriotic lesions of patients. They were also closely located closely to the nerve fibers in the ovarian endometriotic lesions from of patients with pain symptoms. Moreover, fibroblast growth factor 2 (FGF2)-positive mast cells were upregulated in endometriotic lesions. The concentration of FGF2 in ascites and the protein level of fibroblast growth factor receptor 1 (FGFR1) were higher in patients with endometriosis than in those without endometriosis, and they were correlated with pain symptoms. In vitro, estrogen could promote the secretion of FGF2 through G-protein-coupled estrogen receptor 30 (GPR30) via the MEK/ERK pathway in rodent mast cells. Estrogen-stimulated mast cells enhanced the concentration of FGF2 in endometriotic lesions and aggravated endometriosis-related pain in vivo. Targeted inhibition of the FGF2 receptor significantly restrained the neurite outgrowth and calcium influx in dorsal root ganglion (DRG) cells. Administration of FGFR1 inhibitor remarkably elevated the mechanical pain threshold (MPT) and prolonged the heat source latency (HSL) in a rat model of endometriosis. These results suggested that the up-regulated production of FGF2 by mast cells through non-classic estrogen receptor GPR30 plays a vital role in the pathogenesis of endometriosis-related pain.

The Effects of Saposhnikovia divaricata Aqueous Extracts on the Inflammation and Intestinal Microflora in Allergic Rhinitis Mice

Background

Allergic rhinitis (AR) is a type I allergic disease induced by IgE. Traditional Chinese medicine Saposhnikovia divaricata (Turcz.) Schischk (SD) has anti-inflammatory and antiallergic effects.

Materials and Methods

AR model mice were constructed with ovalbumin (OVA) sensitization to observe the improving effect of SD treatment on AR by counting the number of sneezing and rubbing the nose, hematoxylin-eosin, periodic acid-Schiff, and toluidine blue stains. In addition, the allergy and inflammatory cytokines levels and inflammatory cells were observed by ELISA and Wright's-Giemsa stain. The protein levels of the TLR4/TRAF6/NF-κB and IL-6/ROR-γt/STAT3 pathways were measured by immunohistochemistry, quantitative real-time PCR, and western blot. The intestinal microflora abundance in mice was observed by 16S rDNA high-throughput sequencing.

Results

SD treatment inhibited the sneezing and rubbing times of the nose, decreased the degree of a dense arrangement of cells and mucosal swelling and the number of goblet and mast cells of nasal lavage fluid, reduced the levels of IgE, histamine, Leukotriene B4, IL-4, IL-5, TNF-α, IL-6, and IL-17, the eosinophils, neutrophils, and lymphocytes number, the LR4, TRAF6, IL-6, ROR-γt, and STAT3 mRNA levels, respectively, while, it increased the IL-2, IL-10, IFN-γ, and TGF-β1 proteins. SD treatment inhibited the NF-κB, p-STAT3, TLR4, TRAF6, and p-IκBα/IκBα proteins. Besides, the effects of OVA and SD treatments were significantly correlated with the abundance of intestinal microflora. The abundances of Cytophagales, Burkholderia, Alteromonadales, Lactococcus, and Clostridiaceae were changed in SD treatment on AR mice.

Conclusions

This study provides a possibility that the improvement effect of SD treatment on allergies and inflammation in AR mice may be related to the TLR4/TRAF6/NF-κB and IL-6/ROR-γt/STAT3 pathways and intestinal microflora modulation.