Asymmetric Dimethylarginine Blocks Nitric Oxide-Mediated Alcohol-Stimulated Cilia Beating

Abstract

The airway epithelium is exposed to alcohol during drinking through direct exhalation of volatized ethanol from the bronchial circulation. Alcohol exposure leads to a rapid increase in the cilia beat frequency (CBF) of bronchial epithelial cells followed by a chronic desensitization of cilia stimulatory responses. This effect is governed in part by the nitric oxide regulation of cyclic guanosine and adenosine monophosphate-dependent protein kinases (PKG and PKA) and is not fully understood. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, is implicated in the pathogenesis of several pulmonary disorders. We hypothesized that the inhibition of nitric oxide synthase by ADMA blocks alcohol-stimulated increases in CBF. To test this hypothesis, ciliated primary bovine bronchial epithelial cells (BBEC) were preincubated with ADMA (100 µM) and stimulated with 100 mM ethanol. CBF was measured and PKA assayed. By 1 hr, ethanol activated PKA, resulting in elevated CBF. Both alcohol-induced PKA activation and CBF were inhibited in the presence of ADMA. ADMA alone had no effect on PKA activity or CBF. Using a mouse model overexpressing the ADMA-degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH), we examined PKA and CBF in precision-cut mouse lung slices. Alcohol-stimulated increases in lung slice PKA and CBF were temporally enhanced in the DDAH mice versus control mice.

Alcohol Decreases Organic Dust‐Stimulated Airway Epithelial TNF‐Alpha Through a Nitric Oxide and Protein Kinase‐Mediated Inhibition of TACE

“…This leads to ineffective mucociliary clearance as alcohol impacts the airway through the nitric oxide (NO) and PKA pathway (Sisson et al, 1999). Alcohol alters airway epithelial innate defense through changes in both NO and the cAMP-dependent protein kinase (PKA) (Wyatt et al, 2003; Wyatt et al, 2013). In addition, alcohol can lead to leaky lung (Brown et al, 2004), a reduction in alveolar macrophages (Brown et al, 2007) and a decrease in glutathione levels (Holguin et al, 1998) .…”

Alcohol consumption impairs the ependymal cilia motility in the brain ventricles

“…This could potentially provide an explanation for the occurrence of hydrocephalus in patients suffering from acute alcoholism. Previous studies examining the effects of ethanol drinking and other toxic agents on motile cilia function have been mainly performed either on excised tissue or on primary ciliated epithelial cells grown directly from fresh tissue 31 , 32 . However, none of these studies examined the effect of ethanol consumption directly on the motility and function of ependymal cilia in the brain ventricles.…”

“…However, none of these studies examined the effect of ethanol consumption directly on the motility and function of ependymal cilia in the brain ventricles. It has been postulated that exposure of the airway epithelium to volatized ethanol from the bronchial circulation initially leads to a rapid increase in cilia beat frequency followed by a desensitization of ciliary stimulatory response 32 . Our studies reinforce the deleterious effects of ethanol consumption on the sensory function of ependymal cilia and provide a potential explanation for the brain-related symptoms that are associated with ethanol drinking such as headaches, difficulty walking, blurred vision, slurred speech, slowed reaction times, and others.…”

Cyclic GMP and Cilia Motility

“…Similar to previous immunolocalization studies performed in rat [ 69 ] and bovine [ 14 ] ciliated epithelium, NOS3, soluble GC beta, and PKG were also shown by histology to be present in both nasal and tracheal epithelium [ 67 ]. A role for NOS3 in the stimulation of mouse cilia has been subsequently demonstrated with regard to regulation by heat shock protein 90 [ 70 ], antioxidants [ 71 ], and asymmetric dimethylarginine [ 72 ]. Because mice deficient in all 3 isoforms of NOS can be generated [ 73 ], controlled in vivo exposure studies of cilia with regard to NO action are likely to be advanced in the mouse model.…”

“…Pathophysiologic concentrations of alcohol (50–100 mM) desensitize cilia by 18–24 h in vitro and at three weeks in vivo [ 88 , 91 ]. This desensitization, termed alcohol-induced ciliary dysfunction (AICD) involves chronic alcohol-mediated effects of oxidants [ 70 ], asymmetric dimethylarginine [ 72 ], and protein phosphatase 1 [ 92 ]. The AICD effect may be associated with the phosphorylation state of the outer dynein arm proteins.…”