Acidification of phagosomes has been proposed to have a key role in the microbicidal function of phagocytes. Here, we show that in alveolar macrophages the cystic fibrosis transmembrane conductance regulator Cl- channel (CFTR) participates in phagosomal pH control and has bacterial killing capacity. Alveolar macrophages from Cftr-/- mice retained the ability to phagocytose and generate an oxidative burst, but exhibited defective killing of internalized bacteria. Lysosomes from CFTR-null macrophages failed to acidify, although they retained normal fusogenic capacity with nascent phagosomes. We hypothesize that CFTR contributes to lysosomal acidification and that in its absence phagolysosomes acidify poorly, thus providing an environment conducive to bacterial replication.

A systematic literature review and meta-analyses (where appropriate) were performed and the GRADE approach was used to update the previous American Academy of Sleep Medicine Practice Parameters on the treatment of intrinsic circadian rhythm sleep-wake disorders. Available data allowed for positive endorsement (at a second-tier degree of confi dence) of strategically timed melatonin (for the treatment of DSWPD, blind adults with N24SWD, and children/ adolescents with ISWRD and comorbid neurological disorders), and light therapy with or without accompanying behavioral interventions (adults with ASWPD, children/adolescents with DSWPD, and elderly with dementia). Recommendations against the use of melatonin and discrete sleep-promoting medications are provided for demented elderly patients, at a second-and fi rst-tier degree of confi dence, respectively. No recommendations were provided for remaining treatments/ populations, due to either insuffi cient or absent data. Areas where further research is needed are discussed.

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It is well established that ligand-gated chloride flux across the plasma membrane modulates neuronal excitability. We find that a voltage-dependent Cl(-) conductance increases neuronal excitability in immature rodents as well, enhancing the time course of NMDA receptor-mediated miniature excitatory postsynaptic potentials (mEPSPs). This Cl(-) conductance is activated by CaMKII, is electrophysiologically identical to the CaMKII-activated CLC-3 conductance in nonneuronal cells, and is absent in clc-3(-/-) mice. Systematically decreasing [Cl(-)](i) to mimic postnatal [Cl(-)](i) regulation progressively decreases the amplitude and decay time constant of spontaneous mEPSPs. This Cl(-)-dependent change in synaptic strength is absent in clc-3(-/-) mice. Using surface biotinylation, immunohistochemistry, electron microscopy, and coimmunoprecipitation studies, we find that CLC-3 channels are localized on the plasma membrane, at postsynaptic sites, and in association with NMDA receptors. This is the first demonstration that a voltage-dependent chloride conductance modulates neuronal excitability. By increasing postsynaptic potentials in a Cl(-) dependent fashion, CLC-3 channels regulate neuronal excitability postsynaptically in immature neurons.

The absence of the chloride channel CLC-3 in Clcn3−/− mice results in hippocampal degeneration with a distinct temporal-spatial sequence reminiscent of neuronal loss in temporal lobe epilepsy. We examined how the loss of CLC-3 might impact GABAergic synaptic transmission in the hippocampus. An electrophysiological study of synaptic function in Clcn3+/+ and Clcn3-−/− mice in hippocampal slices before the onset of neurodegeneration, revealed a significant decrease in the amplitude and frequency of mIPSCs. We found that CLC-3 colocalizes with the vesicular GABA transporter VGAT in the CA1 region of the hippocampus. Cl−-induced acidification of inhibitory synaptic vesicles showed a significant dependence on CLC-3 expression. The decrement in inhibitory transmission in the Clcn3−/− animals suggests a decrease in neurotransmitter loading of synaptic vesicles which we attributed to defective vesicular acidification. Our observations extend the role of Cl− in inhibitory transmission from that of a postsynaptic permeant species to a presynaptic regulatory element.