Group II subfamily secretory phospholipase A2 enzymes: expression in chronic rhinosinusitis with and without nasal polyps

BACKGROUND

Group II subfamily secretory phospholipases A(2) (sPLA(2)s) are the enzymes that can play a major role in inflammation. However, the presence of group II subfamily sPLA(2)s in human sinonasal mucosa and their roles in chronic rhinosinusitis (CRS) are not well known. The purpose of this study was to investigate the expression of group II subfamily sPLA(2)s in human sinonasal mucosa from controls and CRS patients with and without nasal polyps (NPs) and the regulation of expression by proinflammatory cytokines.

METHODS

Surgical samples were investigated by means of reverse transcriptase polymerase chain reaction (RT-PCR) for evaluation of group II subfamily sPLA(2)s mRNA expression, and the presence and location of group II subfamily sPLA(2)s-positive cells were analyzed by means of immunohistochemistry. Furthermore, nasal explant culture and quantitative RT-PCR techniques were used to investigate the effect of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha on group II subfamily sPLA(2)s mRNA production in sinonasal mucosa.

RESULTS

Messenger RNA expression of sPLA(2)-IIA, -IID, and -IIE was significantly upregulated in tissues from CRS patients compared with control tissues. Among CRS patients, patients without NPs showed significantly stronger expression in sinonasal mucosa than patients with NPs of sPLA(2)-IIA mRNA, and weaker expression of sPLA(2)-IIE mRNA. Immunohistochemistry revealed enhanced protein expression of type II sPLA(2)s and specific type IIA sPLA(2) in epithelial cells and submucosal glands in samples from CRS patients. Stronger type IIA sPLA(2) protein expression was found in samples from CRS patients without NPs when compared with NPs. Nasal explant culture experiments demonstrated that mRNA expression of sPLA(2)-IIA, -IID, and -IIE was dramatically induced by IL-1beta and TNF-alpha.

CONCLUSIONS

The expression of some members of group II subfamily of sPLA(2)s is upregulated in CRS and it may result from IL-1beta and TNF-alpha overexpression. Different individual group II subfamily sPLA(2)s may play different roles in the pathogenesis of CRS with and without NPs.

The role of bone morphogenetic protein-2 in vivo in regeneration of peripheral nerves

We investigated the effects of bone morphogenetic protein-2 (BMP-2) and some other BMPs on regeneration of peripheral motor nerves in vivo. The facial nerves of 24 New Zealand rabbits were crushed to examine a series of retrograde changes in the facial nuclei and axons, in what has been called the "axon reaction". The facial nerves of the experimental group were treated with epineurial coaptation and BMP-2 after the injury. Nerves not treated with BMP-2 were regarded as controls. The expression of BMP-2 was investigated by in situ hybridisation in the neurons of facial nuclei. The electrophysiology, image analysis and transmission electron microscopy were used to evaluate the level of the recovery of facial nerves. The results showed that the axons in the experimental group were thicker and denser than those in the control group four weeks later. The expression of BMP-2 in the neurons of facial nuclei increased after injury. The electron microscopic observations showed that the axons' degeneration in the experimental group was less than that in the control group. Despite the morphological difference between the two groups, there was no apparent difference between them in nerve conduction velocity. These findings suggest that BMP-2 might be involved in the regeneration of facial nerves, and might function as a potential neurotrophic factor.