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Autophagy is a conserved homeostatic process active in all human cells and affecting a spectrum of diseases. Here we use a pharmaceutical screen to discover new mechanisms for activation of autophagy. We identify a subset of pharmaceuticals inducing autophagic flux with effects in diverse cellular systems modelling specific stages of several human diseases such as HIV transmission and hyperphosphorylated tau accumulation in Alzheimer's disease. One drug, flubendazole, is a potent inducer of autophagy initiation and flux by affecting acetylated and dynamic microtubules in a reciprocal way. Disruption of dynamic microtubules by flubendazole results in mTOR deactivation and dissociation from lysosomes leading to TFEB (transcription factor EB) nuclear translocation and activation of autophagy. By inducing microtubule acetylation, flubendazole activates JNK1 leading to Bcl-2 phosphorylation, causing release of Beclin1 from Bcl-2-Beclin1 complexes for autophagy induction, thus uncovering a new approach to inducing autophagic flux that may be applicable in disease treatment.

Autophagy, a homeostatic process whereby eukaryotic cells target cytoplasmic cargo for degradation, plays a broad role in health and disease states. Here we screened the TRIM family for roles in autophagy and found that half of TRIMs modulated autophagy. In mechanistic studies, we show that TRIMs associate with autophagy factors and act as platforms assembling ULK1 and Beclin 1 in their activated states. Furthermore, TRIM5α acts as a selective autophagy receptor. Based on direct sequence-specific recognition, TRIM5α delivered its cognate cytosolic target, a viral capsid protein, for autophagic degradation. Thus, our study establishes that TRIMs can function both as regulators of autophagy and as autophagic cargo receptors, and reveals a basis for selective autophagy in mammalian cells., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Autophagy is a fundamental cell biological process whereby eukaryotic cells form membranes in the cytoplasm to sequester diverse intracellular targets. Although significant progress has been made in understanding the origins of autophagosomal organelles, the source of lipids that support autophagic membrane formation remain an important open question., Results: Here we show that lipid droplets as cellular stores of neutral lipids including triglycerides contribute to autophagic initiation. Lipid droplets, as previously shown, were consumed upon induction of autophagy by starvation. However, inhibition of autophagic maturation by blocking acidification or using dominant negative Atg4(C74A) that prohibits autophagosomal closure did not prevent disappearance of lipid droplets. Thus, lipid droplets continued to be utilized upon induction of autophagy, but not as autophagic substrates in a process referred to as lipophagy. We considered an alternative model whereby lipid droplets were consumed not as a part of lipophagy, but as a potential contributing source to the biogenesis of lipid precursors for nascent autophagosomes. We carried out a screen for a potential link between triglyceride mobilization and autophagy and identified a neutral lipase, PNPLA5, as being required for efficient autophagy. PNPLA5, which localized to lipid droplets, was needed for optimal initiation of autophagy. PNPLA5 was required for autophagy of diverse substrates, including degradation of autophagic adaptors, bulk proteolysis, mitochondrial quantity control, and microbial clearance., Conclusions: Lipid droplets contribute to autophagic capacity by enhancing it in a process dependent on PNPLA5. Thus, neutral lipid stores are mobilized during autophagy to support autophagic membrane formation., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The now well-accepted innate immunity paradigm that autophagy acts as a cell-autonomous defense against intracellular bacteria has its key origins in studies with Mycobacterium tuberculosis, an important human pathogen and a model microorganism infecting macrophages. A number of different factors have been identified that play into the anti-mycobacterial functions of autophagy, and recent in vivo studies in the mouse model of tuberculosis have uncovered additional anti-inflammatory and tissue-sparing functions of autophagy. Complementing these observations, genome wide association studies indicate a considerable overlap between autophagy, human susceptibility to mycobacterial infections and predisposition loci for inflammatory bowel disease. Finally, recent studies show that autophagy is an important regulator and effector of IL-1 responses, and that autophagy intersects with type I interferon pathology-modulating responses., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Autophagy is a cell biological pathway affecting immune responses. In vitro, autophagy acts as a cell-autonomous defense against Mycobacterium tuberculosis, but its role in vivo is unknown. Here we show that autophagy plays a dual role against tuberculosis: antibacterial and anti-inflammatory. M. tuberculosis infection of Atg5(fl/fl) LysM-Cre(+) mice relative to autophagy-proficient littermates resulted in increased bacillary burden and excessive pulmonary inflammation characterized by neutrophil infiltration and IL-17 response with increased IL-1α levels. Macrophages from uninfected Atg5(fl/fl) LysM-Cre(+) mice displayed a cell-autonomous IL-1α hypersecretion phenotype, whereas T cells showed propensity toward IL-17 polarization during nonspecific activation or upon restimulation with mycobacterial antigens. Thus, autophagy acts in vivo by suppressing both M. tuberculosis growth and damaging inflammation.

Autophagy is a fundamental biological process of the eukaryotic cell contributing to diverse cellular and physiological functions including cell-autonomous defense against intracellular pathogens. Here, we screened the Rab family of membrane trafficking regulators for effects on autophagic elimination of Mycobacterium tuberculosis var. bovis BCG and found that Rab8b and its downstream interacting partner, innate immunity regulator TBK-1, are required for autophagic elimination of mycobacteria in macrophages. TBK-1 was necessary for autophagic maturation. TBK-1 coordinated assembly and function of the autophagic machinery and phosphorylated the autophagic adaptor p62 (sequestosome 1) on Ser-403, a residue essential for its role in autophagic clearance. A key proinflammatory cytokine, IL-1β, induced autophagy leading to autophagic killing of mycobacteria in macrophages, and this IL-1β activity was dependent on TBK-1. Thus, TBK-1 is a key regulator of immunological autophagy and is responsible for the maturation of autophagosomes into lytic bactericidal organelles., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Autophagy is a key cytoplasmic biomass and organellar quality and quantity control pathway of the eukaryotic cell. It is particularly suited to capture and degrade large, multi-macromolecular cytosplasmic targets earmarked for degradation or turnover. Typical autophagic cargos represent large swaths of cytosol as a source of energy and anabolic precursors at times of growth restrictions imposed by the absence of growth factors, nutrient limitation or hypoxia. Autophagy is the only effective mechanism for removal of whole organelles such as leaky or surplus mitochondria, disposal of potentially toxic protein aggregates too large for proteasomal removal, and elimination of intracellular microbes including bacteria, protozoa and viruses. Recent studies have shown that human immunodeficiency virus (HIV) is targeted for eliminated by autophagy but that this is countered by the viral protein Nef. Here we review these relationships and underscore the untapped potential of autophagy as a druggable antiviral process., ((c) 2010. Published by Elsevier Ltd.)

The article discusses the role of autophagy against active tuberculosis. Study shows that autophagy protects against Mycobacterium tuberculosis (M. tuberculosis) infection and excessive inflammation in vivo. It states that macrophages defective for autophagy secrete proinflammatory cytokines and in a cell-autonomous fashion.