Pirfenidone ameliorated AGE-induced EMT and attenuated peritoneal fibrosis in peritoneal mesothelial cells

Pathophysiological Mechanisms of Peritoneal Fibrosis and Peritoneal Membrane Dysfunction in Peritoneal Dialysis

The characteristic feature of chronic peritoneal damage in peritoneal dialysis (PD) is a decline in ultrafiltration capacity associated with pathological fibrosis and angiogenesis. The pathogenesis of peritoneal fibrosis is attributed to bioincompatible factors of PD fluid and peritonitis. Uremia is associated with peritoneal membrane inflammation that affects fibrosis, neoangiogenesis, and baseline peritoneal membrane function. Net ultrafiltration volume is affected by capillary surface area, vasculopathy, peritoneal fibrosis, and lymphangiogenesis. Many inflammatory cytokines induce fibrogenic growth factors, with crosstalk between macrophages and fibroblasts. Transforming growth factor (TGF)-β and vascular endothelial growth factor (VEGF)-A are the key mediators of fibrosis and angiogenesis, respectively. Bioincompatible factors of PD fluid upregulate TGF-β expression by mesothelial cells that contributes to the development of fibrosis. Angiogenesis and lymphangiogenesis can progress during fibrosis via TGF-β-VEGF-A/C pathways. Complement activation occurs in fungal peritonitis and progresses insidiously during PD. Analyses of the human peritoneal membrane have clarified the mechanisms by which encapsulating peritoneal sclerosis develops. Different effects of dialysates on the peritoneal membrane were also recognized, particularly in terms of vascular damage. Understanding the pathophysiologies of the peritoneal membrane will lead to preservation of peritoneal membrane function and improvements in technical survival, mortality, and quality of life for PD patients.

miR-128-3p inhibits high-glucose-induced peritoneal mesothelial cells fibrosis via PAK2/SyK/TGF-β1 axis

AIM

To elucidate the mechanism of miR-128-3p in peritoneal fibrosis (PF).

METHODS

Peritoneal mesothelial cells (PMCs) were dealt with high glucose (HG) for 3 days. The expressions of miR-128-3p, p21-activated kinase 2 (PAK2), spleen tyrosine kinase (SyK), and transforming growth factor-β1 (TGF-β1) were detected with quantitative real-time reverse transcription polymerase chain reaction. The levels of IL-1β, TNF-α, IL-6, and monocyte chemotactic protein-1 in supernatant were measured by ELISA. Proteins of TGF-β1, SyK, PAK2, α-SMA, collagen I, vimentin, ERK/AP-1, and IκBα/NF-κB pathway related proteins were measured by Western blot. The correlation between miR-128-3p and PAK2 was found by bioinformatics analysis and luciferase reporter gene analysis.

RESULTS

miR-128-3p was decreased while PAK2, SyK, and TGF-β1 were increased in HG-induced PMCs. Moreover, miR-128-3p inhibited HG-induced fibrosis and inflammation in PMCs by targeting PAK2. PAK2 activated SyK, which induced TGF-β1 expression through ERK/AP-1 and IκBα/NF-κB pathways to promote HG-induced fibrosis of PMCs.

CONCLUSION

miR-128-3p inhibited HG-induced PMCs fibrosis via PAK2/SyK/TGF-β1 axis.

House dust mite-induced Akt-ERK1/2-C/EBP beta pathway triggers CCL20-mediated inflammation and epithelial-mesenchymal transition for airway remodeling

House dust mite (HDM) allergens cause inflammatory responses and chronic allergic diseases such as bronchial asthma and atopic dermatitis. Here, we investigate the mechanism by which HDM induces C-C chemokine ligand 20 (CCL20) expression to promote chronic inflammation and airway remodeling in an HDM-induced bronchial asthma mouse model. We showed that HDM increased CCL20 levels via the Akt-ERK1/2-C/EBPβ pathway. To investigate the role of CCL20 in chronic airway inflammation and remodeling, we made a mouse model of CCL20-induced bronchial asthma. Treatment of anti-CCL20Ab in this mouse model showed the reduced airway hyper-responsiveness and inflammatory cell infiltration into peribronchial region by neutralizing CCL20. In addition, CCL20 induced the Nod-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome activation through NLRP3 deubiquitination and transcriptional upregulation in BEAS-2B cells. As expected, anti-CCL20Ab markedly suppressed NLRP3 activation induced by CCL20. Moreover, HDM-induced CCL20 leads to epithelial-mesenchymal transition in the lung epithelium which appears to be an important regulator of airway remodeling in allergic asthma. We also found that anti-CCL20Ab attenuates airway inflammation and remodeling in an HDM-induced mouse model of bronchial asthma. Taken together, our results suggest that HDM-induced CCL20 is required for chronic inflammation that contributes airway remodeling in a mouse model of asthma.