Peritoneal inflammation and fibrosis in C-reactive protein transgenic mice undergoing peritoneal dialysis solution treatment
NEPHROLOGY
Authors: Poon, Peter Yam-Kau; Lan, Hui-Yao; Kwan, Bonnie Ching-Ha; Huang, Xiao-Ru; Chow, Kai-Ming; Szeto, Cheuk-Chun; Li, Philip Kam-Tao
Abstract
AimC-reactive protein (CRP) is a mediator of systemic inflammation. Peritoneal dialysis (PD) is known to cause peritoneal inflammation and fibrosis. We compare the degree of peritoneal inflammation and fibrosis in wild-type (WT) and CRP-transgenic (Tg) mice after PD treatment. MethodsWT (n=7) and CRP-Tg (n=10) C57BL/6J mice (all male, 10-12 weeks old) were injected intra-peritoneally with 4.25% dextrose PD solution (3mL/mouse) daily for 28days, followed by a 2-h peritoneal equilibration test (PET). The mice were then killed. Parietal peritoneal and omental tissues were collected for the assessment of inflammation and fibrosis. ResultsAfter 28days of PD treatment, CRP-Tg mice had higher dialysate-to-plasma (D/P) creatinine ratio than that of WT mice. Parietal peritoneum of the CRP-Tg mice was more cellular and thicker than that of the WT mice. CRP-Tg mice also had higher connective tissue growth factor (CTGF), intercellular adhesion molecule 1 (ICAM1) and tumor necrosis factor (TNF) RNA expressions as well as immunohistochemical staining in the parietal peritoneum than that of the WT mice. ConclusionsCRP-Tg mice have significantly more inflammation and fibrosis than WT mice after PD treatment. Our results suggest that CRP play a role in inflammation and fibrosis induced by PD. The implication of our results to human PD therapy needs further investigations. Summary at a Glance This interesting study demonstrated that in CRP-transgenic mice, CRP seemed to play a role in inflammation and fibrosis of the peritoneum rather than just being an innocent bystander in inflammation, in a model of peritoneal dialysis.
Intercellular adhesion molecule 1 serves as a primary cognate receptor for the Type IV pilus of nontypeable Haemophilus influenzae
CELLULAR MICROBIOLOGY
Authors: Novotny, Laura A.; Bakaletz, Lauren O.
Abstract
Nontypeable Haemophilus influenzae (NTHI) utilizes the Type IV pilus (Tfp) to adhere to respiratory tract epithelial cells thus colonizing its human host; however, the host cell receptor to which this adhesive protein binds is unknown. From a panel of receptors engaged by Tfp expressed by other bacterial species, we showed that the majority subunit of NTHI Tfp, PilA, bound to intercellular adhesion molecule 1 (ICAM1) and that this interaction was both specific and of high affinity. Further, Tfp-expressing NTHI inoculated on to polarized respiratory tract epithelial cells that expressed ICAM1 were significantly more adherent compared to Tfp-deficient NTHI or NTHI inoculated on to epithelial cells to which ICAM1 gene expression was silenced. Moreover, pre-incubation of epithelial cells with recombinant soluble PilA (rsPilA) blocked adherence of NTHI, an outcome that was abrogated by admixing rsPilA with ICAM1 prior to application on to the target cells. Epithelial cells infected with adenovirus or respiratory syncytial virus showed increased expression of ICAM1; this outcome supported augmented adherence of Tfp-expressing NTHI. Collectively, these data revealed the cognate receptor for NTHI Tfp as ICAM1 and promote continued development of a Tfp-targeted vaccine for NTHI-induced diseases of the airway wherein upper respiratory tract viruses play a key predisposing role.