Elevated Monocytic Interleukin-8 Expression under Intermittent Hypoxia Condition and in Obstructive Sleep Apnea Patients.

Obstructive sleep apnea (OSA) is a disease with great cardiovascular risk. Interleukin-8 (IL-8), an important chemokine for monocyte chemotactic migration, was studied under intermittent hypoxia condition and in OSA patients. Monocytic THP-1 cells were used to investigate the effect of intermittent hypoxia on the regulation of IL-8 by an intermittent hypoxic culture system. The secreted protein and mRNA levels were studied by means of enzyme-linked immunosorbent assay and RT/real-time PCR. The chemotactic migration of monocytes toward a conditioned medium containing IL-8 was performed by means of the transwell filter migration assay. Peripheral venous blood was collected from 31 adult OSA patients and RNA was extracted from the monocytes for the analysis of IL-8 expression. The result revealed that intermittent hypoxia enhanced the monocytic THP-1 cells to actively express IL-8 at both the secreted protein and mRNA levels, which subsequently increased the migration ability of monocytes toward IL-8. The ERK, PI3K and PKC pathways were demonstrated to contribute to the activation of IL-8 expression by intermittent hypoxia. In addition, increased monocytic IL-8 expression was found in OSA patients, with disease severity dependence and diurnal changes. This study concluded the monocytic IL-8 gene expression can be activated by intermittent hypoxia and increased in OSA patients.

Simvastatin inhibits the proliferation of HL-60 clone 15- derived eosinophils by inducing the arrest of the cell cycle in the G1/S phase.

Eosinophils and their granular proteins are crucial for combating allergic airway diseases. Eosinophils derived from HL-60 clone 15 (HC15) cells have been established as a feasible alternative cell model for human primary eosinophils. Simvastatin, a cholesterol-lowering agent, has been shown to exhibit anti-inflammatory and anti-allergic effects. Among the granular eosinophil proteins, eosinophil cationic protein (ECP) is the one best recognised in allergic airway diseases. The aim of our study is to investigate the effect and regulatory mechanisms of simvastatin on ECP levels derived from eosinophils. Both HC15 cell counts and ECP levels decreased after simvastatin treatment in the animal and cell models; however, after a cell count adjustment, simvastatin was not observed to exert a significantly inhibitory effect on ECP expression. Real-time polymerase chain reaction and Western blotting analyses demonstrated that simvastatin did not inhibit the intracellular formation or release of ECP. Cell cycle analysis showed that the percentage of HC15 cells in the G1 and S phases significantly increased and decreased, respectively, after simvastatin treatment. Simvastatin inhibited the proliferation of HC15-derived eosinophils by inducing G1/S cell cycle arrest in a dose-dependent manner. Its effect on the cell cycle involved the downregulation of cyclin A but without the presence of mevalonate; therefore, total ECP expression from eosinophils decreased, not by suppressing the actual formation or release of ECP but by arresting the G1/S cell cycle phase and inhibiting subsequent cell proliferation through the mevalonate pathway.

Intense pulsed light effects on the expression of extracellular matrix proteins and transforming growth factor beta-1 in skin dermal fibroblasts cultured within contracted collagen lattices.

BACKGROUND: Emerging clinical evidence suggests that intense pulsed light (IPL) treatment may exert some beneficial effects on photoaged skin. The molecular mechanisms underlying this IPL effect have not been fully elucidated. OBJECTIVE: To examine the effects of IPL irradiation on normal human dermal fibroblasts grown in contracted collagen lattices. METHODS: Human skin fibroblasts cultured in contracted collagen lattices were irradiated with IPL with triple pulses of 7 ms with a pulse interval of 70 ms and fluences of 20, 50, and 75 J/cm(2). Twenty-four hours after the irradiation, cell viability, messenger RNA (mRNA), and protein levels of extracellular matrix proteins (e.g., collagen I, collagen III, and fibronectin) and transforming growth factor beta-1 (TGF-beta1) were evaluated using dye exclusion, real-time reverse transcriptase polymerase chain reaction, and enzyme-linked immunosorbent assay, respectively. RESULTS: A dose-dependent increase in viable cells was demonstrated after the IPL irradiation. There was no significant change in mRNA levels of collagen I and fibronectin. Upregulated expression of collagen III and TGF-beta1 in dermal fibroblasts was verified. CONCLUSIONS: The analytical results presented here provide a potential mechanistic explanation for the mechanism of clinical photorejuvenation effects of IPL that involves the increase of extracellular matrix construction by upregulating the gene expressions of collagen III and TGF-beta1.