Biology subjects

Wileman, T.

Publications and source records attributed to Wileman, T..

7 recordsLinked to original sources

bioRxiv2025

LRRK2 is activated by phosphatidylinositol 3-phosphate in conjunction with CASM

LRRK2 is a Parkinsons disease (PD)-associated kinase that phosphorylates Rab GTPases. Hyperactivation of LRRK2, which is thought to cause PD, occurs on stressed endolysosomal membranes via CASM (conjugation of ATG8 to single membranes) and Rab, whereas the involvement of specific membrane lipids remained unclear. Here, we found that LRRK2 was potently activated upon treatment with PIKfyve inhibitors that increase cellular phosphatidylinositol 3-phosphate (PI3P) levels, and that additional treatment with the class III phosphoinositide 3-kinase (PI3K) inhibitors blocking PI3P generation suppressed LRRK2 activation. Cellular PI3P levels were indeed correlated with the LRRK2 kinase activity. CASM-induced LRRK2 activation, but not CASM itself, was suppressed by PI3K inhibitors, whereas inhibition of CASM or Rab12/Rab29 suppressed LRRK2 activation induced by PIKfyve inhibitors. LRRK2 and phospho-Rab10 were co-localized with PI3P on LAMP1-positive enlarged vacuoles, and LRRK2 directly bound PI3P in vitro via its N-terminal positively charged amino acids. Together, we propose an updated mechanism of LRRK2 activation that requires CASM, Rab and PI3P-rich membranes.

cell biology↗

bioRxiv2024

ATG16L1 WD domain regulates lipid trafficking to maintain plasma membrane integrity to limit influenza virus infection

The non-canonical functions of autophagy protein ATG16L1 are dependent on a C-terminal WD domain. Recent studies show that the WD domain is required for conjugation of LC3 to single membranes during endocytosis and phagocytosis, where it is thought to promote fusion with lysosomes. Studies in cells lacking the WD domain suggest additional roles in the regulation of cytokine receptor recycling and plasma membrane repair. The WD domain also protects mice against lethal influenza virus in vivo. Here, analysis of mice lacking the WD domain ({Delta}WD) shows enrichment of cholesterol in brain tissue suggesting a role for the WD domain in cholesterol transport. Brain tissue and cells from {Delta}WD mice showed reduced cholesterol and phosphatidylserine (PS) in the plasma membrane. Cells from {Delta}WD mice also showed an intracellular accumulation of cholesterol predominantly in late endosomes in cell culture. Infection studies using IAV suggest that the loss of cholesterol and PS from the plasma membrane in cells from {Delta}WD mice results in increased endocytosis and nuclear delivery of IAV, as well as increased IFN{beta} and ISG expression. Upregulation of IL-6, IFN{beta} and ISG mRNA were observed in ex vivo precision cut lung slices from {Delta}WD mice both at rest and in response to IAV infection. Overall, we present evidence that regulation of lipid transport by the WD domain of ATG16L1 may have downstream implications in attenuating viral infection and limiting lethal cytokine signaling.

cell biology↗

bioRxiv2023

The V-ATPase-ATG16L1 axis recruits LRRK2 to facilitate lysosomal stress responses

Leucine-rich repeat kinase 2 (LRRK2), a Rab kinase associated with Parkinsons disease and several inflammatory diseases, has been shown to localize to stressed lysosomes and get activated to regulate lysosomal homeostasis. However, the mechanisms of LRRK2 recruitment and activation have not been well understood. Here we found that the ATG8 conjugation system regulates the recruitment of LRRK2 as well as LC3 onto single membranes of stressed lysosomes/phagosomes. This recruitment did not require FIP200-containing autophagy initiation complex, nor did it occur on double-membrane autophagosomes, suggesting independence from canonical autophagy. Consistently, LRRK2 recruitment was regulated by the V-ATPase-ATG16L1 axis, which requires the WD40 domain of ATG16L1 and specifically mediates ATG8 lipidation on single membranes. This mechanism was also responsible for the lysosomal stress-induced activation of LRRK2 and the resultant regulation of lysosomal secretion and enlargement. These results indicate that the V-ATPase-ATG16L1 axis serves a novel non-autophagic role in the maintenance of lysosomal homeostasis by recruiting LRRK2.

molecular biology↗

bioRxiv2023

TECPR1 provides E3-ligase like activity to the ATG5-ATG12 complex to conjugate LC3/ATG8 to damaged lysosomes

Autophagosomes deliver cytosolic material to lysosomes to provide amino acids during starvation and to degrade damaged proteins and organelles to maintain tissue homeostasis. Delivery to lysosomes requires LC3/ATG8 (LC3), the major membrane protein of the autophagosome, that uses adaptor proteins to capture cargo and recruits tethering and SNARE proteins to promote fusion with lysosomes. LC3 is also recruited to endo-lysosome compartments in response to increases in vacuolar pH to facilitate degradation of material entering cells by endocytosis. A series of ubiquitin-like reactions conjugate LC3 to amino groups exposed by phosphatidylethanolamine (PE) or phosphatidylserine (PS) in target membranes. The E1 and E2-ubiquitin-like activities of ATG7 and ATG3 use thioester bonds to transfer LC3 to the ATG5-ATG12 conjugate. At the same time binding of ATG16L1 to ATG5-ATG12 provides the E3 ubiquitin-ligase like activity necessary to conjugate LC3 to PE or PS. The ATG5-ATG12 conjugate can also bind TECPR1 (tectonin beta propeller repeat-containing protein) which shares an ATG5 interaction (AIR) region with ATG16L1 and can binds LC3 directly through a LC3 interaction region (LIR). In this study we have used cells lacking ATG16L1 to determine if TECPR1 can substitute for ATG16L1 during LC3 conjugation. The results show that ATG16L1-/-MEFS can conjugate LC3 to lysosomes damaged by chloroquine or LLOMes and conjugation is dependent on the ubiquitin-like enzymes ATG3, ATG5 and ATG7 upstream of ATG16L1. TECPR1, ATG5 and galectin 3 are recruited to LAMP positive damaged lysosomes in the absence of ATG16L1 suggesting that TECPR-1 recruits ATG5-ATG12 to conjugate LC3 to damaged lysosomes. This was confirmed when truncation of TECPR1 at the central PH domain required for lysosome binding prevented LC3 conjugation, and LC3 conjugation could be restored by full length TECPR1. Recruitment of TECPR1 to damaged lysosomes required the N-terminal LIR motif and was partially dependent on the central PH domain that binds PI4P exposed during lysosome repair. TECPR1 can therefore conjugate LC3 to damaged lysosomes independently of ATG16L1 by providing E3 ligase-like activity to ATG5-ATG12. Direct conjugation of LC3 by TECPR1 may contribute to the autophagosome tethering functions reported for TECPR1 by increasing recruitment of cargo receptors, tethering proteins and SNARE proteins required for fusion with lysosomes and protein degradation. TECPR1-dependent conjugation of LC3 may also facilitate lysosome repair pathways involving autophagic lysosomal reformation and transcriptional activation of autophagy by TFEB.

cell biology↗

bioRxiv2020

The WD and linker domains of ATG16L1 required for non canonical autophagy limit lethal influenza A virus infection at epithelial surfaces.

Respiratory viruses such as influenza A virus (IAV) and SARS-CoV-2 (Covid-19) cause pandemic infections where cytokine storm syndrome, lung inflammation and pneumonia lead to high mortality. Given the high social and economic cost of these viruses, there is an urgent need for a comprehensive understanding of how the airways defend against virus infection. Viruses entering cells by endocytosis are killed when delivered to lysosomes for degradation. Lysosome delivery is facilitated by non-canonical autophagy pathways that conjugate LC3 to endo-lysosome compartments to enhance lysosome fusion. Here we use mice lacking the WD and linker domains of ATG16L1 to demonstrate that non-canonical autophagy protects mice from lethal IAV infection of the airways. Mice with systemic loss of non-canonical autophagy are exquisitely sensitive to low-pathogenicity murine-adapted IAV where extensive viral replication throughout the lungs, coupled with cytokine amplification mediated by plasmacytoid dendritic cells, leads to fulminant pneumonia, lung inflammation and high mortality. IAV infection was controlled within epithelial barriers where non-canonical autophagy slowed fusion of IAV with endosomes and reduced activation of interferon signalling. This was consistent with conditional mouse models and ex vivo analysis showing that protection against IAV infection of lung was independent of phagocytes and other leukocytes. This establishes non-canonical autophagy pathways in airway epithelial cells as a novel innate defence mechanism that can restrict IAV infection and lethal inflammation at respiratory surfaces.

microbiology↗

bioRxiv2019

Identification of master regulators in goblet cells and Paneth cells using transcriptomics profiling of gut organoids and multi-layered networks

The epithelial lining of the small intestine consists of multiple cell types, including Paneth cells and goblet cells, that work in cohort to maintain gut health. 3D in vitro cultures of human primary epithelial cells, called organoids, have become a key model to study the functions of Paneth cells and goblet cells in normal and diseased conditions. Advances in these models include the ability to skew differentiation to particular lineages, providing a useful tool to study cell type specific function/dysfunction in the context of the epithelium. Here, we use comprehensive profiling of mRNA, microRNA and long non-coding RNA expression to confirm that Paneth cell and goblet cell enrichment of murine small intestinal organoids (enteroids) establishes a physiologically accurate model. We employ network analysis to infer the regulatory landscape altered by skewing differentiation, and using knowledge of cell type specific markers, we predict key regulators of cell type specific functions: Cebpa, Jun, Nr1d1 and Rxra specific to Paneth cells, Gfi1b and Myc specific for goblet cells and Ets1, Nr3c1 and Vdr shared between them. Links identified between these regulators and cellular phenotypes of inflammatory bowel disease (IBD) suggest that global regulatory rewiring during or after differentiation of Paneth cells and goblet cells could contribute to IBD aetiology. Future application of cell type enriched enteroids combined with the presented computational workflow can be used to disentangle multifactorial mechanisms of these cell types and propose regulators whose pharmacological targeting could be advantageous in treating IBD patients with Crohns disease or ulcerative colitis.\n\nTable of contentsWe demonstrate the application of network biology techniques to increase understanding of intestinal dysbiosis through studying transcriptomics data from Paneth and goblet cell enriched enteroids.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC=\"FIGDIR/small/575845v4_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (25K):\norg.highwire.dtl.DTLVardef@16637e5org.highwire.dtl.DTLVardef@1dfaa77org.highwire.dtl.DTLVardef@1307c00org.highwire.dtl.DTLVardef@1d16e0_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2018

Integrative analysis of Paneth cell proteomic data from intestinal organoids reveals functional processes affected in Crohn’s disease due to autophagy impairment

Summary statementUsing an integrative approach encompassing intestinal organoid culture, proteomics, transcriptomics and protein-protein interaction networks, we list Paneth cell functions dependent on autophagy.\n\nAbstractPaneth cells are key epithelial cells providing an antimicrobial barrier and maintaining integrity of the small intestinal stem cell niche. Paneth cell abnormalities are unfortunately detrimental to gut health and often associated with digestive pathologies such as Crohns disease or infections. Similar alterations are observed in individuals with impaired autophagy, a process which recycles cellular components. The direct effect of autophagy-impairment on Paneth cells has not been analysed. To investigate this, we generated a mouse model lacking Atg16l1 specifically in intestinal epithelial cells making these cells impaired in autophagy. Using 3D intestinal organoids enriched for Paneth cells, we compared the proteomic profiles of wild-type (WT) and autophagy-impaired organoids. We used an integrated computational approach combining protein-protein interaction networks, autophagy targeted proteins and functional information to identify the mechanistic link between autophagy-impairment and disrupted pathways. Of the 284 altered proteins, 198 (70%) were more abundant in autophagy-impaired organoids, suggesting reduced protein degradation. Interestingly, these differentially abundant proteins comprised 116 proteins (41%), predicted targets of the selective autophagy proteins p62, LC3 and ATG16L1. Our integrative analysis revealed autophagy-mediated mechanisms degrading proteins key to Paneth cell functions, such as exocytosis, apoptosis and DNA damage repair. Transcriptomic profiling of additional organoids confirmed that 90% of the observed changes upon autophagy alteration affect protein level and not gene expression. We performed further validation experiments showing differential lysozyme secretion, confirming our computationally inferred down-regulation of exocytosis. Our observations could explain how protein level alterations affect Paneth cell homeostatic functions upon autophagy impairment.

systems biology↗