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Chronic obstructive pulmonary disease (COPD) involves aberrant airway inflammatory responses to cigarette smoke (CS) that are associated with epithelial cell dysfunction, cilia shortening, and mucociliary clearance disruption. Exposure to CS reduced cilia length and induced autophagy in vivo and in differentiated mouse tracheal epithelial cells (MTECs). Autophagy-impaired (Becn1+/- or Map1lc3B-/-) mice and MTECs resisted CS-induced cilia shortening. Furthermore, CS increased the autophagic turnover of ciliary proteins, indicating that autophagy may regulate cilia homeostasis. We identified cytosolic deacetylase HDAC6 as a critical regulator of autophagy-mediated cilia shortening during CS exposure. Mice bearing an X chromosome deletion of Hdac6 (Hdac6-/Y) and MTECs from these mice had reduced autophagy and were protected from CS-induced cilia shortening. Autophagy-impaired Becn1-/-, Map1lc3B-/-, and Hdac6-/Y mice or mice injected with an HDAC6 inhibitor were protected from CS-induced mucociliary clearance (MCC) disruption. MCC was preserved in mice given the chemical chaperone 4-phenylbutyric acid, but was disrupted in mice lacking the transcription factor NRF2, suggesting that oxidative stress and altered proteostasis contribute to the disruption of MCC. Analysis of human COPD specimens revealed epigenetic deregulation of HDAC6 by hypomethylation and increased protein expression in the airways. We conclude that an autophagy-dependent pathway regulates cilia length during CS exposure and has potential as a therapeutic target for COPD. [ABSTRACT FROM AUTHOR]

The article discusses the evidence emerging for the role of autophagy and selective autophagy in cell survival, cell death, and immune and inflammatory response related to the pathogenesis of complex lung diseases. It discusses the principal components of the autophagic process. The dual nature of autophagy in the lung and the challenge posed by this duality for designing autophagy-based diagnostic and therapeutic targets in lung disease are also examined.

Mitochondrial dysfunction is associated with the manifestation and origin of a plethora of diseases and disorders. Whilst classically the role of these archetypical ‘powerhouses’ in many disease phenotypes has been attributed to their ability to regulate cell metabolism and cell death pathways, emerging data posit that mitochondria may also act as powerful initiators and masters of the innate immune response. This new paradigm complements the current mitochondrial dogma, whereby molecules endogenously present on or inside the mitochondria may act as immune regulators in response to stress or pathogens and may also be responsible for the initiation and/or manifestation of chronic inflammation observed in many diseases and disorders. [Copyright &y& Elsevier]

The discovery that some selective serotonin transporter- (SSRI) and norepinephrine transporter- (NSRI) targeting antidepressants have the potential to act as anticancer agents adds greatly to their diverse pharmacological application. We report that the SSRI fluoxetine and the NSRI maprotiline are potent antiproliferative agents against human Burkitt lymphoma (BL), having little effect on normal blood cells. The results of this study show that although there is low-level expression of the norepinephrine transporter (NET) in some BL cells, NET is not involved in fluoxetine- or maprotiline-mediated cell death, as neither norepinephrine nor other NET inhibitors prevented this death. Of other NET ligands investigated for activity, only desipramine was found to have a similar effect to maprotiline and fluoxetine, suggesting the existence of a common selective structural modality for cell death and aiding in the future development of more potent analogs. In this study, we also show evidence to support previous reports that the serotonin transporter (SERT) has no involvement in antidepressant-mediated cell death, as SERT-specific ligands were unable to prevent fluoxetine or maprotiline cell death and not all SERT ligands could induce cell death. Although no target has yet been identified for the action of these compounds, the cell death elicited is potent, selective, and worthy of future investigation. [ABSTRACT FROM AUTHOR]