Effects of purinergic stimulation on ciliary beat frequency and chloride secretion in sinusitis

Drug-induced ciliogenesis in pancreatic cancer cells is facilitated by the secreted ATP-purinergic receptor signaling pathway

Malignant transformation of cells is often accompanied by the loss of the primary cilium, a protruding microtubule-based sensory organelle, suggesting that it plays an “onco-suppressive” role. Therefore, restoration of the primary cilium is being explored as a new therapeutic approach to attenuate tumor growth. Recently, several commonly used chemotherapeutic drugs have been identified to induce the primary cilium in pancreatic cancer cells. The mechanisms by which these drugs re-express the cilium remain, however, enigmatic. Here, evaluation of a panel of diverse ciliogenic drugs on pancreatic cancer cell models revealed a significant positive relationship between drug-induced extracellular ATP, released through pannexin channels, and the extent of primary cilium induction. Moreover, cilium induction by these drugs was hampered in the presence of the ATP degrading enzyme, apyrase, and in the presence of the pan-purinergic receptor inhibitor, suramin. Our findings reveal that ciliogenic drug-induced re-expression of the primary cilium in pancreatic cancer cells is, at least in certain contexts, dependent on a hitherto unrecognized autocrine/paracrine loop involving the extracellular ATP-purinergic receptor signaling pathway that can be exploited in a therapeutic approach targeting at restoring the primary cilium.

P2X ion channel receptors and inflammation

Neuroinflammation limits tissue damage in response to pathogens or injury and promotes repair. There are two stages of inflammation, initiation and resolution. P2X receptors are gaining attention in relation to immunology and inflammation. The P2X7 receptor in particular appears to be an essential immunomodulatory receptor, although P2X1 and P2X4 receptors also appear to be involved. ATP released from damaged or infected cells causes inflammation by release of inflammatory cytokines via P2X7 receptors and acts as a danger signal by occupying upregulated P2X receptors on immune cells to increase immune responses. The purinergic involvement in inflammation is being explored for the development of novel therapeutic strategies.

The effects of a 1.8 GHz continuous electromagnetic fields on mucociliary transport of human nasal mucosa

OBJECTIVES/HYPOTHESIS

The aim of this study was to investigate the effects of a 1.8 GHz continuous electromagnetic fields (EMF) on human nasal mucociliary transport, and to determine the pathophysiology of ciliary beat frequency (CBF) during an EMF-induced change.

METHODS

Human nasal mucosa cells were exposed to a 1.8 GHz EMF (SAR=1.0 W/kg), and CBF was analyzed using an optical flow technique with the peak detection method.

RESULTS

The 1.8 GHz-exposed group showed a decreased CBF when compared to the control group. In the cytotoxicity assay, difference in survival rates was not found between the two groups. In the EMF-exposed group, protein kinase C (PKC) activity was increased during a PKC activity assay. The broad PKC inhibitor, Calphostin C abolished the EMF-induced decrease of CBF. The EMF-induced decrease of CBF was abolished by GF 109203X, a novel PKC (nPKC) isoform inhibitor, whereas the decrease was not attenuated by Gö-6976, a specific inhibitor of conventional PKC (cPKC) isoform.

CONCLUSIONS

EMF may inhibit CBF via an nPKC-dependent mechanism. Therefore, we have confirmed that EMF could decrease CBF by increasing PKC activity.

The effect of histamine on ciliary beat frequency in the acute phase of allergic rhinitis

BACKGROUND

There have been few studies about the effect of histamine on ciliary beat frequency (CBF) in the acute phase of allergic rhinitis.

OBJECTIVE

The present study was designed to investigate CBF in the acute phase of allergic rhinitis and the effect of histamine on CBF.

MATERIALS AND METHODS

Nasal septal mucosae were obtained from 13 mice that had been systemically immunized and locally challenged with ovalbumin (OVA) (group A), 11 OVA immunized and phosphate-buffered saline-challenged mice (group B), and 12 nontreated negative control mice (group C). The CBFs were observed within 20 minutes of local challenge with OVA. Ciliary beat frequencies were measured before and after treatment with 10(-5), 10(-3), and 10(-1) mol/L histamine and after administering antihistamine or Dulbecco's modified Eagle's medium to histamine-exposed mucosa.

RESULTS

The baseline CBF in group A was higher than in groups B and C. After treatment with 10(-1) mol/L histamine, CBF in all groups decreased to 0 within 5 to 7 minutes, whereas treatment with 10(-5) or 10(-3) mol/L histamine had no effect. The application of 100 μmol/L fexofenadine or Dulbecco's modified Eagle's medium solution restored histamine-induced ciliostasis to near baseline CBF after 10 minutes.

CONCLUSIONS

Ciliary beat frequency increased in the acute phase of a mouse model of allergic rhinitis. Physiologic concentrations of histamine had no effect on CBF, and thus, it appears that other mechanisms control CBF in the acute phase of allergic rhinitis.