The plant protein NbP3IP directs degradation of Rice stripe virus p3 silencing suppressor protein to limit virus infection through interaction with the autophagy-related protein NbATG8

In plants, autophagy is involved in responses to viral infection. However, the role of host factors in mediating autophagy to suppress viruses is poorly understood. A previously uncharacterized plant protein, NbP3IP, was shown to interact with p3, an RNA-silencing suppressor protein encoded by Rice stripe virus (RSV), a negative-strand RNA virus. The potential roles of NbP3IP in RSV infection were examined. NbP3IP degraded p3 through the autophagy pathway, thereby affecting the silencing suppression activity of p3. Transgenic overexpression of NbP3IP conferred resistance to RSV infection in Nicotiana benthamiana. RSV infection was promoted in ATG5- or ATG7-silenced plants and was inhibited in GAPC-silenced plants where autophagy was activated, confirming the role of autophagy in suppressing RSV infection. NbP3IP interacted with NbATG8f, indicating a potential selective autophagosomal cargo receptor role for P3IP. Additionally, the rice NbP3IP homolog (OsP3IP) also mediated p3 degradation and interacted with OsATG8b and p3. Through identification of the involvement of P3IP in the autophagy-mediated degradation of RSV p3, we reveal a new mechanism to antagonize the infection of RSV, and thereby provide the first evidence that autophagy can play an antiviral role against negative-strand RNA viruses.

The structure of human ATG9A and its interplay with the lipid bilayer

ATG9, the only transmembrane protein in the core macroautophagy/autophagy machinery, is a key player in the early stages of autophagosome formation. Yet, the lack of a high-resolution structure of ATG9 was a major impediment in understanding its three-dimensional organization and function. We recently solved a high-resolution cryoEM structure of the ubiquitously expressed human ATG9A isoform. The structure revealed that ATG9A is a domain-swapped homotrimer with a unique fold, and has an internal network of branched cavities. In cellulo analyses demonstrated the functional importance of the cavity-lining residues. These cavities could serve as conduits for transport of hydrophilic moieties, such as lipid headgroups, across the bilayer. Finally, structure-guided molecular dynamics predicted that ATG9A has membrane-bending properties, which is consistent with its localization to highly curved membranes.

The Autophagy-Related Protein GABARAP Is Induced during Overwintering in the Bean Bug (Hemiptera: Alydidae)

In most insects dependent on food resources that deplete seasonally, mechanisms exist to protect against starvation. Insects overcome periods of food depletion using diapause-associated physiological mechanisms, such as increased energy resources in fat bodies and suppression of metabolism. Because autophagy supplies energy resources through the degradation of intracellular components, we hypothesized that it might be an additional strategy to combat starvation during overwintering. In this study, we measured the abundance of the proteins involved in the signaling pathway of autophagy during overwintering in adults of the bean bug Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), which must withstand the periodic depletion of its host plants from late fall to early spring. Although the levels of gamma-aminobutyric acid receptor-associated protein (GABARAP) markedly increased after the cessation of food supply, AMP-activated protein kinase (AMPK) and target of rapamycin (TOR) were not found to be associated with food depletion. Thus, food depletion appears to induce autophagy independent of AMPK and TOR. The GABARAP levels significantly increased universally when the food supply ceased, irrespective of the diapause status of adults and low-temperature conditions. In overwintering diapause adults under seminatural conditions, the GABARAP levels significantly increased during early spring. Thus, autophagy appears to assist the survival of the bean bugs under natural conditions of food deficiency.

Manganese induces autophagy dysregulation: The role of S-nitrosylation in regulating autophagy related proteins in vivo and in vitro

Exposure to excess levels of manganese (Mn) may lead to nitrosative stress and neurotoxic effects on the central nervous system (CNS). The dysfunction of autophagy correlates with Mn-induced nitrosative stress; however, the exact mechanism of Mn-mediated autophagy dysfunction is still unclear. Three S-nitrosylated target proteins, namely, JNK, Bcl-2, and IKKβ, were classified as the pivotal signaling pathway mediators that could play a role in the regulation of autophagy. To reveal whether these three proteins were involved in Mn-mediated autophagy dysregulation, we studied the effects of Mn on C57/BL6 mice and human neuroblastoma cells. Exposing the mice or cells, to 300 μmol/kg or 200 μM Mn, inhibited the degradation system of the autophagy-lysosome pathway. Additionally, in Mn-treated mice or cells, S-nitrosylated JNK, Bcl-2, and IKKβ increased while the level of their phosphorylation reduced. The interaction of Beclin1 and Bcl-2 significantly increased in response to 200 μM Mn, whereas the decrease in phosphorylation of AMPK activated the mTOR pathway. We then used 20 μM 1400 W, an iNOS-specific inhibitor, to neutralize the nitrosative stress induced by Mn. Our results show that 1400 W reduced the S-nitrosylated JNK, Bcl-2, and Ikkβ and relieved their downstream signaling molecular functions. Moreover, pretreatment with 20 μM 1400 W alleviated Mn-induced autophagic dysregulation and nerve cell injury. These findings revealed that S-nitrosylated JNK, Bcl-2, and IKKβ are crucial signaling molecules in the Mn-mediated autophagic dysfunction.

Lou Gehrig's Disease (ALS): UBQLN2 Mutations Strike Out of Phase

In this issue of Structure, Dao et al. (2019) report that ALS-linked mutations in the Pxx domain of Ubiquilin 2 (UBQLN2) differentially influence the protein's phase separation abilities. The affect is by reducing the temperature and UBQLN2 concentration necessary for liquid-liquid phase separation droplet formation and by modulating UBQLN2 oligomerization.

ATG9A supplies PtdIns4P to the autophagosome initiation site

The identity of the platform supporting the initiation and formation of the nascent autophagosome, the phagophore, is not fully understood. Nucleation and expansion of the phagophore membrane requires a coordinated flux or activation of specific proteins and membrane lipids at the initiation site. The transmembrane protein ATG9A is essential for macroautophagy/autophagy and proposed to be an initiator of the phagophore by directing or facilitating the delivery of proteins and lipids to the initiation site. Upon amino acid starvation, ATG9A-containing vesicles are formed from the Golgi complex and endosomal compartments and translocate to the initiation site. Unravelling the complement of proteins and lipids brought by ATG9A vesicles to the forming autophagosome is essential to further understand the initiation of autophagy.

[Astragalus polysaccharide inhibits autophagy and regulates expression of autophagy-related proteins in lung cancer A549 cells induced by xanthine oxidase]

Objective To investigate the effects of Astragalus polysaccharide (APS) on autophagy and expression of microtubule-associated protein 1 light chain 3B (LC3B), mammalian target of rapamycin (mTOR) and beclin1 in xanthine oxidase (XOD)-induced autophagic model of non-small cell lung cancer A549 cells. Methods A549 cells were divided into five groups: control group, model group, 100, 200 and 400 μg/mL APS-treated group. Except for control group, all groups were administered XOD for 24 hours to establish autophagic models. Morphology of autophagosome was detected by transmission electron microscopy (TEM) and the number was counted by monodansylcadaverine (MDC) staining. The expression levels of LC3B, beclin1 and mTOR were detected by Western blot analysis. Results Compared with the control group, the number of autophagosome in the model group increased; the expression of LC3B and beclin1 significantly increased; while the expression of mTOR significantly decreased. Compared with the model group, the number of autophagosome decreased remarkably; the expression of LC3B and beclin1 severely decreased, and the expression of mTOR obviously increased in 200 or 400 μg/mL APS-treated group. Conclusion APS reduces the level of autophagy, down-regulates the expression of LC3B and beclin1, and increases mTOR expression in the autophagic model of A549 cells induced by XOD.

CEACAM-1 promotes myocardial injury following coxsackievirus infection by regulating the coxsackievirus-adenovirus receptor

OBJECTIVE

To determine the effects and mechanism of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1, CC1)-mediated regulation of the Coxsackie and Adenovirus Receptor (CAR) after Coxsackievirus B3 (CVB3) infection.

METHODS

A mouse CC1 overexpression recombinant virus was constructed, followed by insertion of a pLVX-CEACAM 1-zsgreen-puro (rLV-CEACAM 1) plasmid into the recombinant retrovirus. Cardiac myocytes were assigned into different groups according to various treatments. The apoptosis rate and cell activity in each group were observed. Further, CAR expression and SYK, IL-1β, and p-SYK levels were measured.

RESULTS

The recombinant retrovirus titer was measured as 1.5 × 10 TUs/ml. The apoptosis rate of cardiac myocytes in the CC1 overexpression plus CVB3 group was significantly elevated, and the relative expression of the CAR gene was the highest in the CC1 overexpression plus CVB3 group. TNF-α and IL-1β levels increased due to CC1 overexpression and further increased after CVB3 infection. CAR protein expression also changed along with the levels of CC1, SYK, and TNF-α after infection.

CONCLUSION

CC1 may promote CAR expression after CVB3 infection and regulate CAR protein expression by activating the CC1-SYK-TNF-α signaling axis during the infection process.

Phosphatidylinositol 4,5-bisphosphate controls Rab7 and PLEKHM1 membrane cycling during autophagosome-lysosome fusion

The small GTPase Rab7 is a key organizer of receptor sorting and lysosomal degradation by recruiting of a variety of effectors depending on its GDP/GTP-bound state. However, molecular mechanisms that trigger Rab7 inactivation remain elusive. Here we find that, among the endosomal pools, Rab7-positive compartments possess the highest level of PI4P, which is primarily produced by PI4K2A kinase. Acute conversion of this endosomal PI4P to PI(4,5)P2 causes Rab7 dissociation from late endosomes and releases a regulator of autophagosome-lysosome fusion, PLEKHM1, from the membrane. Rab7 effectors Vps35 and RILP are not affected by acute PI(4,5)P2 production. Deletion of PI4K2A greatly reduces PIP5Kγ-mediated PI(4,5)P2 production in Rab7-positive endosomes leading to impaired Rab7 inactivation and increased number of LC3-positive structures with defective autophagosome-lysosome fusion. These results reveal a late endosomal PI4P-PI(4,5)P2 -dependent regulatory loop that impacts autophagosome flux by affecting Rab7 cycling and PLEKHM1 association.

USP8 maintains embryonic stem cell stemness via deubiquitination of EPG5

Embryonic stem cells (ESCs) can propagate in an undifferentiated state indefinitely in culture and retain the potential to differentiate into any somatic lineage as well as germ cells. The catabolic process autophagy has been reported to be involved in ESC identity regulation, but the underlying mechanism is still largely unknown. Here we show that EPG5, a eukaryotic-specific autophagy regulator which mediates autophagosome/lysosome fusion, is highly expressed in ESCs and contributes to ESC identity maintenance. We identify that the deubiquitinating enzyme USP8 binds to the Coiled-coil domain of EPG5. Mechanistically, USP8 directly removes non-classical K63-linked ubiquitin chains from EPG5 at Lysine 252, leading to enhanced interaction between EPG5 and LC3. We propose that deubiquitination of EPG5 by USP8 guards the autophagic flux in ESCs to maintain their stemness. This work uncovers a novel crosstalk pathway between ubiquitination and autophagy through USP8-EPG5 interaction to regulate the stemness of ESCs.

Protective Effects of CISD2 and Influence of Curcumin on CISD2 Expression in Aged Animals and Inflammatory Cell Model

BACKGROUND

Inflammation and mitochondrial dysfunction have been linked to trauma, neurodegeneration, and aging. Impairment of CISD2 expression may trigger the aforementioned pathological conditions in neural cells. We previously reported that curcumin attenuates the downregulation of CISD2 in animal models of spinal cord injury and lipopolysaccharide (LPS)-treated neuronal cells. In this study, we investigate (1) the role of CISD2 and (2) how curcumin regulates CISD2 in the aging process.

MATERIALS AND METHODS

The serial expression of CISD2 and the efficacy of curcumin treatment were evaluated in old (104 weeks) mice and long-term cultures of neural cells (35 days in vitro, DIV). LPS-challenged neural cells (with or without siCISD2 transfection) were used to verify the role of curcumin on CISD2 underlying mitochondrial dysfunction.

RESULTS

In the brain and spinal cord of mice aged P2, 8, 25, and 104 weeks, we observed a significant decrease in CISD2 expression with age. Curcumin treatment in vivo and in vitro was shown to upregulate CISD2 expression; attenuate inflammatory response in neural cells. Moreover, curcumin treatment elevated CISD2 expression levels and prevented mitochondrial dysfunction in LPS-challenged neural cells. The beneficial effects of curcumin in either non-stressed or LPS-challenged cells that underwent siCISD2 transfection were significantly lower than in respective groups of cells that underwent scrambled siRNA-transfection.

CONCLUSIONS

We hypothesize that the protective effects of curcumin treatment in reducing cellular inflammation associated trauma, degenerative, and aging processes can be partially attributed to elevated CISD2 expression. We observed a reduction in the protective effects of curcumin against injury-induced inflammation and mitochondrial dysfunction in cells where CISD2 expression was reduced by siCISD2.

Bidirectional Control of Autophagy by BECN1 BARA Domain Dynamics

Membrane targeting of the BECN1-containing class III PI 3-kinase (PI3KC3) complexes is pivotal to the regulation of autophagy. The interaction of PI3KC3 complex II and its ubiquitously expressed inhibitor, Rubicon, was mapped to the first β sheet of the BECN1 BARA domain and the UVRAG BARA2 domain by hydrogen-deuterium exchange and cryo-EM. These data suggest that the BARA β sheet 1 unfolds to directly engage the membrane. This mechanism was confirmed using protein engineering, giant unilamellar vesicle assays, and molecular simulations. Using this mechanism, a BECN1 β sheet-1 derived peptide activates both PI3KC3 complexes I and II, while HIV-1 Nef inhibits complex II. These data reveal how BECN1 switches on and off PI3KC3 binding to membranes. The observations explain how PI3KC3 inhibition by Rubicon, activation by autophagy-inducing BECN1 peptides, and inhibition by HIV-1 Nef are mediated by the switchable ability of the BECN1 BARA domain to partially unfold and insert into membranes.

HOPS-dependent endosomal fusion required for efficient cytosolic delivery of therapeutic peptides and small proteins

Protein therapeutics represent a significant and growing component of the modern pharmacopeia, but their potential to treat human disease is limited because most proteins fail to traffic across biological membranes. Recently, we discovered a class of cell-permeant miniature proteins (CPMPs) containing a precisely defined, penta-arginine (penta-Arg) motif that traffics readily to the cytosol and nucleus of mammalian cells with efficiencies that rival those of hydrocarbon-stapled peptides active in animals and man. Like many cell-penetrating peptides (CPPs), CPMPs enter the endocytic pathway; the difference is that CPMPs containing a penta-Arg motif are released efficiently from endosomes, while other CPPs are not. Here, we seek to understand how CPMPs traffic from endosomes into the cytosol and what factors contribute to the efficiency of endosomal release. First, using two complementary cell-based assays, we exclude endosomal rupture as the primary means of endosomal escape. Next, using an RNA interference screen, fluorescence correlation spectroscopy, and confocal imaging, we identify VPS39-a gene encoding a subunit of the homotypic fusion and protein-sorting (HOPS) complex-as a critical determinant in the trafficking of CPMPs and hydrocarbon-stapled peptides to the cytosol. Although CPMPs neither inhibit nor activate HOPS function, HOPS activity is essential to efficiently deliver CPMPs to the cytosol. CPMPs localize within the lumen of Rab7+ and Lamp1+ endosomes and their transport requires HOPS activity. Overall, our results identify Lamp1+ late endosomes and lysosomes as portals for passing proteins into the cytosol and suggest that this environment is prerequisite for endosomal escape.

Determination of Autophagy in the Caco-2 Spontaneously Differentiating Model of Intestinal Epithelial Cells

The Caco-2 colorectal cancer cell line is widely used as a model for intestinal differentiation and barrier function. These cells, upon reaching confluency, spontaneously differentiate into enterocyte-like cells, synthesize intestinal enzymes, and form domes. Caco-2 cells also undergo autophagy in the course of differentiation. The criteria to establish the induction of autophagy in cells are already well established. Here, we describe the protocol for the spontaneous differentiation of Caco-2 cells and the detection of autophagy using Western blot, flow cytometry, and immunofluorescence.

Novel compound heterozygous EPG5 mutations consisted with a missense mutation and a microduplication in the exon 1 region identified in a Japanese patient with Vici syndrome

Vici syndrome is a rare, autosomal recessive, multisystem disorder, characterized by agenesis of the corpus callosum, cataracts, psychomotor delay, cardiomyopathy, hypopigmentation, and recurrent infections. Mutations in the ectopic P-granules autophagy protein 5 homolog gene (EPG5), which encodes a key autophagy regulator, are responsible for this syndrome. A 3-year-old Japanese girl manifesting similar symptoms to those found in patients with Vici syndrome showed intractable diarrhea, rather than immunodeficiency. Whole exome sequencing identified only a heterozygous variant in EPG5, NM_020964.2(EPG5):c.3389A > C (p.His1130Pro), which was inherited from her mother. Sequencing analyses of the EPG5 messenger RNA showed only an altered nucleotide "C" at position, c.3389, indicating decreased expression of the wild-type allele. Microarray-based comparative genomic hybridization revealed a de novo microduplication in the exon 1 region. Large exon deletions and duplications of EPG5 have never been reported so far. This was considered the cause of the decreased expression of the wild-type allele. In conclusion, we successfully identified novel compound heterozygous mutations in EPG5 in a patient who was clinically considered to have Vici syndrome.

Enhanced oligodendrocyte maturation and myelination in a mouse model of Timothy syndrome

To study the role of L-type voltage-gated Ca++ channels in oligodendrocyte development, we used a mouse model of Timothy syndrome (TS) in which a gain-of-function mutation in the α1 subunit of the L-type Ca++ channel Cav1.2 gives rise to an autism spectrum disorder (ASD). Oligodendrocyte progenitor cells (OPCs) isolated from the cortex of TS mice showed greater L-type Ca++ influx and displayed characteristics suggestive of advanced maturation compared to control OPCs, including a more complex morphology and higher levels of myelin protein expression. Consistent with this, expression of Cav1.2 channels bearing the TS mutation in wild-type OPCs triggered process formation and promoted oligodendrocyte-neuron interaction via the activation of Ca++ /calmodulin-dependent protein kinase II. To ascertain whether accelerated OPC maturation correlated with functional enhancements, we examined myelination in the TS brain at different postnatal time points. The expression of myelin proteins was significantly higher in the corpus callosum, cortex and striatum of TS animals, and immunohistochemical analysis for oligodendrocyte stage-specific markers revealed an increase in the density of myelinating oligodendrocytes in several areas of the TS brain. Along the same line, electron microscopy studies in the corpus callosum of TS animals showed significant increases both in the percentage of myelinated axons and in the thickness of myelin sheaths. In summary, these data indicate that OPC development and oligodendrocyte myelination is enhanced in the brain of TS mice, and suggest that this mouse model of a syndromic ASD is a useful tool to explore the role of L-type Ca++ channels in myelination.

Mutant UBQLN2 promotes toxicity by modulating intrinsic self-assembly

UBQLN2 is one of a family of proteins implicated in ubiquitin-dependent protein quality control and integrally tied to human neurodegenerative disease. Whereas wild-type UBQLN2 accumulates in intraneuronal deposits in several common age-related neurodegenerative diseases, mutations in the gene encoding this protein result in X-linked amyotrophic lateral sclerosis/frontotemporal dementia associated with TDP43 accumulation. Using in vitro protein analysis, longitudinal fluorescence imaging and cellular, neuronal, and transgenic mouse models, we establish that UBQLN2 is intrinsically prone to self-assemble into higher-order complexes, including liquid-like droplets and amyloid aggregates. UBQLN2 self-assembly and solubility are reciprocally modulated by the protein's ubiquitin-like and ubiquitin-associated domains. Moreover, a pathogenic UBQLN2 missense mutation impairs droplet dynamics and favors amyloid-like aggregation associated with neurotoxicity. These data emphasize the critical link between UBQLN2's role in ubiquitin-dependent pathways and its propensity to self-assemble and aggregate in neurodegenerative diseases.

Ushering in the cardiac role of Ubiquilin1

Protein quality control (PQC) mechanisms are essential for maintaining cardiac function, and alterations in this pathway influence multiple forms of heart disease. Since heart disease is the leading cause of death worldwide, understanding how the delicate balance between protein synthesis and degradation is regulated in the heart demands attention. The study by Hu et al. reveals that the extraproteasomal ubiquitin receptor Ubiquilin1 (Ubqln1) plays an important role in cardiac ubiquitination-proteasome coupling, particularly in response to myocardial ischemia/reperfusion injury, thereby suggesting that this may be a new avenue for therapeutics.

Poliovirus induces autophagic signaling independent of the ULK1 complex

Poliovirus (PV), like many positive-strand RNA viruses, subverts the macroautophagy/autophagy pathway to promote its own replication. Here, we investigate whether the virus uses the canonical autophagic signaling complex, consisting of the ULK1/2 kinases, ATG13, RB1CC1, and ATG101, to activate autophagy. We find that the virus sends autophagic signals independent of the ULK1 complex, and that the members of the autophagic complex are not required for normal levels of viral replication. We also show that the SQSTM1/p62 receptor protein is not degraded in a conventional manner during infection, but is likely cleaved in a manner similar to that shown for coxsackievirus B3. This means that SQSTM1, normally used to monitor autophagic degradation, cannot be used to accurately monitor degradation during poliovirus infection. In fact, autophagic degradation may be affected by the loss of SQSTM1 at the same time as autophagic signals are being sent. Finally, we demonstrate that ULK1 and ULK2 protein levels are greatly reduced during PV infection, and ATG13, RB1CC1, and ATG101 protein levels are reduced as well. Surprisingly, autophagic signaling appears to increase as ULK1 levels decrease. Overexpression of wild-type or dominant-negative ULK1 constructs does not affect virus replication, indicating that ULK1 degradation may be a side effect of the ULK1-independent signaling mechanism used by PV, inducing complex instability. This demonstration of ULK1-independent autophagic signaling is novel and leads to a model by which the virus is signaling to generate autophagosomes downstream of ULK1, while at the same time, cleaving cargo receptors, which may affect cargo loading and autophagic degradative flux. Our data suggest that PV has a finely-tuned relationship with the autophagic machinery, generating autophagosomes without using the primary autophagy signaling pathway.

ABBREVIATIONS

ACTB - actin beta; ATG13 - autophagy related 13; ATG14 - autophagy related 14; ATG101 - autophagy related 101; BECN1 - beclin 1; CVB3 - coxsackievirus B3; DMV - double-membraned vesicles; EM - electron microscopy; EMCV - encephalomyocarditis virus; EV-71 - enterovirus 71; FMDV - foot and mouth disease virus; GFP - green fluorescent protein; MAP1LC3B/LC3B - microtubule associated protein 1 light chain 3 beta; MOI - multiplicity of infection; MTOR - mechanistic target of rapamycin kinase; PIK3C3 - phosphatidylinositol 3-kinase catalytic subunit type 3; PRKAA2 - protein kinase AMP-activated catalytic subunit alpha 2; PSMG1 - proteasome assembly chaperone 1; PSMG2 - proteasome assembly chaperone 2PV - poliovirus; RB1CC1 - RB1 inducible coiled-coil 1; SQSTM1 - sequestosome 1; ULK1 - unc-51 like autophagy activating kinase 1; ULK2 - unc-51 like autophagy activating kinase 2; WIPI1 - WD repeat domain, phosphoinositide interacting 1.

LRRK2 is a negative regulator of Mycobacterium tuberculosis phagosome maturation in macrophages

Mutations in the leucine-rich repeat kinase 2 (LRRK2) are associated with Parkinson's disease, chronic inflammation and mycobacterial infections. Although there is evidence supporting the idea that LRRK2 has an immune function, the cellular function of this kinase is still largely unknown. By using genetic, pharmacological and proteomics approaches, we show that LRRK2 kinase activity negatively regulates phagosome maturation via the recruitment of the Class III phosphatidylinositol-3 kinase complex and Rubicon to the phagosome in macrophages. Moreover, inhibition of LRRK2 kinase activity in mouse and human macrophages enhanced Mycobacterium tuberculosis phagosome maturation and mycobacterial control independently of autophagy. In vivo, LRRK2 deficiency in mice resulted in a significant decrease in M. tuberculosis burdens early during the infection. Collectively, our findings provide a molecular mechanism explaining genetic evidence linking LRRK2 to mycobacterial diseases and establish an LRRK2-dependent cellular pathway that controls M. tuberculosis replication by regulating phagosome maturation.

Low-level expression of EPG5 leads to an attenuated Vici syndrome phenotype

Vici syndrome is a multisystem disorder characterized by agenesis of the corpus callosum, oculocutaneous hypopigmentation, cataracts, cardiomyopathy, combined immunodeficiency, failure to thrive, profound developmental delay, and acquired microcephaly. Most individuals are severely affected and have a markedly reduced life span. Here we describe an 8-year-old boy with a history of developmental delay, agenesis of the corpus callosum, failure to thrive, myopathy, and well-controlled epilepsy. He was initially diagnosed with a mitochondrial disorder, based in part upon nonspecific muscle biopsy findings, but mitochondrial DNA mutation analysis revealed no mutations. Whole exome sequencing revealed compound heterozygosity for two EPG5 variants, inherited in trans. One was a known pathogenic mutation in exon 13 (c.2461C > T, p.Arg821X). The second was reported as a variant of unknown significance found within intron 16, six nucleotides before the exon 17 splice acceptor site (c.3099-6C > G). Reverse transcription-polymerase chain reaction of the EPG5 mRNA showed skipping of exon 17-which maintains an open reading frame-in 77% of the transcript, along with 23% expression of wild-type mRNA suggesting that intronic mutations may affect splicing of the EPG5 gene and result in symptoms. However, the expression of 23% wild-type mRNA may result in a significantly attenuated Vici syndrome phenotype.

The MT-CO1 V83I Polymorphism is a Risk Factor for Primary Open-Angle Glaucoma in African American Men

Purpose

We investigate the function of the V83I polymorphism (m.6150G>A, rs879053914) in the mitochondrial cytochrome c oxidase subunit 1 (MT-CO1) gene and its role in African American (AA) primary open-angle glaucoma (POAG).

Methods

This study used Sanger sequencing (1339 cases, 850 controls), phenotypic characterization of Primary Open-Angle African American Glaucoma Genetics study (POAAGG) cases, a masked chart review of CO1 missense cases (V83I plus M117T, n = 29) versus wild type cases (n = 29), a yeast 2-hybrid (Y2H) cDNA library screen, and quantification of protein-protein interactions by Y2H and ELISA.

Results

The association of V83I with POAG in AA was highly significant for men (odds ratio [OR] 6.5; 95% confidence interval [CI] 2.0-21.3, P = 0.0001), but not for women (OR 1.1; 95% CI, 0.62-2.00, P = 0.78). POAG cases having CO1 double missense mutation (V83I + M117T, L1c2 haplogroup) had a higher cup-to-disc ratio (0.77 vs. 0.71, P = 0.04) and significantly worse visual function (average pattern standard deviation, 6.5 vs. 4.3, P = 0.009; average mean deviation -10.4 vs. -4.5, P = 0.006) when compared to matched wild type cases (L1b haplogroup). Interaction of the V83I region of CO1 with amyloid beta peptide (Aβ) was confirmed by ELISA assay, and this interaction was abrogated by V83I. A Y2H screen of an adult human brain cDNA library with the V83 region of CO1 as bait retrieved the UBQLN1 gene.

Conclusions

The V83I polymorphism was associated strongly with POAG in AA men and disrupts Aβ-binding to CO1. This region also interacts with a neuroprotective protein, UBQLN1.

The Vici syndrome protein EPG5 regulates intracellular nucleic acid trafficking linking autophagy to innate and adaptive immunity

Vici syndrome is a human inherited multi-system disorder caused by recessive mutations in EPG5, encoding the EPG5 protein that mediates the fusion of autophagosomes with lysosomes. Immunodeficiency characterized by lack of memory B cells and increased susceptibility to infection is an integral part of the condition, but the role of EPG5 in the immune system remains unknown. Here we show that EPG5 is indispensable for the transport of the TLR9 ligand CpG to the late endosomal-lysosomal compartment, and for TLR9-initiated signaling, a step essential for the survival of human memory B cells and their ultimate differentiation into plasma cells. Moreover, the predicted structure of EPG5 includes a membrane remodeling domain and a karyopherin-like domain, thus explaining its function as a carrier between separate vesicular compartments. Our findings indicate that EPG5, by controlling nucleic acids intracellular trafficking, links macroautophagy/autophagy to innate and adaptive immunity.

Clinical significance of ubiquilin 1 in gastric cancer

Ubiquilin 1 (UBQLN1) plays an essential role in the regulation of protein degradations which is involved in the pathophysiology of neurodegenerative diseases and cancer. This study aimed to investigate the expression level of UBQLN1 in gastric cancer and evaluated the relationship between its expression and clinicopathological characteristics, as well as prognostic of patients with gastric cancer. Immunohistochemistry (IHC) was used to detect the expression levels of UBQLN1 in 179 pairs of gastric cancer and adjacent normal tissues. The UBQLN1 was significantly upregulated in gastric cancer tissue. High UBQLN1 expression was associated with high histological grade, invasion, lymph node metastasis, and tumor node metastasis (TNM) stage III (P < .001). Multivariate Cox analysis showed that larger tumor size (HR = 3.125, 95%CI: 2.031-4.808, P < .001), histological grade 3 (HR = 15.313, 95%,CI: 8.075-29.041, P < .001), pT3 + pT4 (HR = 3.224, 95%CI: 1.389-7.483, P = .006), LNM (HR = 4.467, 95%CI: 2.404-8.302, P < .001), TNM stage III (HR = 2.152, 95%CI: 1.289-3.594, P = .003), and high UBQLN1 expression (HR = 2.547, 95%CI: 1.511-4.292, P < .001) were significantly associated with worse prognosis of patients with gastric cancer. In conclusion, high UBQLN1 expression was an independent worse prognostic factor for patients with gastric cancer.

Evaluation of urinary autophagy transcripts expression in diabetic kidney disease

BACKGROUND

We identified and validated novel urinary autophagy markers in diabetic kidney disease (DKD) based on bioinformatics analysis and clinical validation.

PATIENTS & METHODS

We retrieved three novel autophagy genes related to DKD from public microarray databases, namely; microtubule-associated protein light chain (MAP1LC3A), WD Repeat Domain, Phosphoinositide Interacting 2 (WIPI2), and RB1-Inducible Coiled-Coil 1 (RB1CC1). Secondly we assessed the expression of the chosen autophagy transcript in urine sediment of 86 patients with DKD and 74 (age and sex matched) controls by reverse transcription quantitative real-time PCR.

RESULTS

The urinary expression levels of MAP1LC3A, WIPI, RB1CC1 were significantly lower in DKD than control group (P<0.001).The receiver-operating characteristic curve (ROC) analyses that each urinary autophagy transcript showed high sensitivity and specificity for distinguishing DKD from control (MAP1LC3A, 81.4% and 81.1%; WIPI, 74.4% and 67.6%, and RB1CC1, 81.4%,70.3%, respectively). Notably, a negative correlation was found between these autophagy markers, serum creatinine and urinary albumin creatinine ratio. The sensitivity and specificity of this urinary autophagy based panel reached 90.6% and 60% in diagnosis of DKD.

CONCLUSION

We identified and validated a novel diagnostic urinary autophagy based panel with high sensitivity and moderate specificity representing a vital player in the pathogenesis of DKD.

Autopsy findings in EPG5-related Vici syndrome with antenatal onset

Vici syndrome is one of the most extensive inherited human multisystem disorders and due to recessive mutations in EPG5 encoding a key autophagy regulator with a crucial role in autophagosome-lysosome fusion. The condition presents usually early in life, with features of severe global developmental delay, profound failure to thrive, (acquired) microcephaly, callosal agenesis, cataracts, cardiomyopathy, hypopigmentation, and combined immunodeficiency. Clinical course is variable but usually progressive and associated with high mortality. Here, we present a fetus, offspring of consanguineous parents, in whom callosal agenesis and other developmental brain abnormalities were detected on fetal ultrasound scan (US) and subsequent MRI scan in the second trimester. Postmortem examination performed after medically indicated termination of pregnancy confirmed CNS abnormalities and provided additional evidence for skin hypopigmentation, nascent cataracts, and hypertrophic cardiomyopathy. Genetic testing prompted by a suggestive combination of features revealed a homozygous EPG5 mutation (c.5870-1G>A) predicted to cause aberrant splicing of the EPG5 transcript. Our findings expand the phenotypical spectrum of EPG5-related Vici syndrome and suggest that this severe condition may already present in utero. While callosal agenesis is not an uncommon finding in fetal medicine, additional presence of hypopigmentation, cataracts and cardiomyopathy is rare and should prompt EPG5 testing.

Muscle pathology in Vici syndrome-A case study with a novel mutation in EPG5 and a summary of the literature

Vici syndrome is a disorder characterized by myopathy, cardiomyopathy, agenesis of the corpus callosum, immunodeficiency, cataracts, hypopigmentation, microcephaly, gross developmental delay and failure to thrive. It is caused by mutations in EPG5, which encodes a protein involved in the autophagy pathway. Although myopathy is part of the syndrome, few publications have described the muscle pathology. We present a detailed morphological analysis in a boy with Vici syndrome due to a novel homozygous one-base deletion in EPG5 (c.784delA), and we review the histopathological findings from previous reports. Muscle biopsy was performed at three months of age and demonstrated small vacuolated fibers, frequently with internal nuclei, and expressing developmental and fast myosin isoforms. There was an increase in acid phosphatase activity in the small fibers, which also showed LAMP-2 upregulation, glycogen accumulation and contained numerous p62-positive inclusions and some lipid droplets. Electron microscopy demonstrated hypoplastic fibers with massive glycogen accumulation and extensive disorganization of the myofibrils. This study expands the muscle pathological features of Vici syndrome and demonstrates a pattern of vacuolar myopathy with glycogen storage and immature, hypoplastic and atrophic muscle fibers. Increased lysosomes and accumulation of p62 are in line with a disturbance of the autophagic pathway as an essential part of the pathogenesis.

Defects in autophagosome-lysosome fusion underlie Vici syndrome, a neurodevelopmental disorder with multisystem involvement

Vici syndrome (VICIS) is a rare, autosomal recessive neurodevelopmental disorder with multisystem involvement characterized by agenesis of the corpus callosum, cataracts, cardiomyopathy, combined immunodeficiency, developmental delay, and hypopigmentation. Mutations in EPG5, a gene that encodes a key autophagy regulator, have been shown to cause VICIS, however, the precise pathomechanism underlying VICIS is yet to be clarified. Here, we describe detailed clinical (including brain MRI and muscle biopsy) and genetic features of nine Japanese patients with VICIS. Genetic dissection of these nine patients from seven families identified 14 causative mutations in EPG5. These included five nonsense, two frameshift, three splicing, one missense, and one multi-exon deletion mutations, and two initiation codon variants. Furthermore, cultured skin fibroblasts (SFs) from two affected patients demonstrated partial autophagic dysfunction. To investigate the function of EPG5, siRNA based EPG5 knock-down, and CRISPR/Cas9 mediated EPG5 knock-out HeLa cells were generated. EPG5-depleted cells exhibited a complete block of autophagic flux caused by defective autophagosome-lysosome fusion. Unexpectedly, endocytic degradation was normal in both VICIS SFs and EPG5 depleted cells, suggesting that EPG5 function is limited to the regulation of autophagosome-lysosome fusion.

Effects of thermosensitive chitosan-gelatin based hydrogel containing glutathione on Cisd2-deficient chondrocytes under oxidative stress

Aging is considered as a primary risk factor in the development of osteoarthritis (OA) which associated with mitochondrial dysfunction and oxidative stress. CDGSH iron sulfur domain 2 (Cisd2) deficiency causes mitochondrial dysfunction and drive premature aging. In the present study, thermosensitive chitosan-gelatin based hydrogel containing glutathione was developed as injectable drug delivery system for administration by minimal invasive surgery for the treatment of OA. Cisd2 deficiency (Cisd2^-/-) mouse induced pluripotent stem cells-derived chondrocytes were established and characterized. The results suggested that 100μM of glutathione may be an optimal concentration to treat Cisd2^-/- chondrocytes without cytotoxicity. The developed hydrogel showed sustained release profile of the glutathione and could decrease the reactive oxygen species level. Post-treatment of glutathione-loaded hydrogel could rescue Cisd2^-/- chondrocytes from oxidative damage via increasing catalase activity, down-regulation of inflammation, and decreasing apoptosis. These results suggest that thermosensitive glutathione-loaded hydrogel may be a potential antioxidant therapeutic strategy for treating Cisd2^-/- chondrocytes in the near future.

Loss of WDFY3 ameliorates severity of serum transfer-induced arthritis independently of autophagy

WDFY3 is a master regulator of selective autophagy that we recently showed to interact with TRAF6 and augment RANKL-induced osteoclastogenesis in vitro and in vivo via the NF-κB pathway. Since the NF-κB pathway plays a major role in inflammation herein, we investigate the role of WDFY3 in an arthritis animal model. Our data show that WDFY3 conditional knockout mice (Wdfy3^loxP/loxP-LysM-Cre+) were protected in the K/BxN serum transfer-induced arthritis animal model. These effects were independent of alterations in starvation-induced autophagy as evidenced by Western blot analysis of the autophagy marker LC3, autophagosome formation in osteoclast precursors and lysosome formation in osteoclasts derived from WDFY3-cKO mice compared to controls. Moreover, we demonstrate by immunofluorescence and co-immunoprecipitation that WDFY3 interacts with SQSTM1 in macrophages and osteoclasts. Collectively, our data suggest that loss of WDFY3 in myeloid cells leads to reduced severity of inflammatory arthritis independently of WDFY3 function in starvation-induced autophagy.

Reduced body weight gain in ubiquilin-1 transgenic mice is associated with increased expression of energy-sensing proteins

Ubiquilin-1 (Ubqln1), a ubiquitin-like protein, is implicated in a variety of pathophysiological processes, but its role in mediating body weight gain or metabolism has not been determined. Here, we demonstrate that global overexpression of Ubqln1 in a transgenic (Tg) mouse reduces the animal's body weight gain. The decreased body weight gain in Tg mice is associated with lower visceral fat content and higher metabolic rate. The Ubqln1 Tg mice exhibited reduced leptin and insulin levels as well as increased insulin sensitivity manifested by homeostatic model assessment of insulin resistance. Additionally, the reduced body weight in Tg mice was associated with the upregulation of two energy-sensing proteins, sirtuin1 (SIRT1) in the hypothalamus and AMP-activated protein kinase (AMPK) in the skeletal muscle. Consistent with the in vivo results, overexpression of Ubqln1 significantly increased SIRT1 and AMPK levels in the mouse embryonic fibroblast cell culture. Thus, our results not only establish the link between Ubqln1 and body weight regulation but also indicate that the metabolic function of Ubqln1 on body weight may be through regulating energy-sensing proteins.

1,25(OH)2 D3 attenuates hepatic steatosis by inducing autophagy in mice

OBJECTIVE

1,25(OH)₂ D₃ has been reported to attenuate liver steatosis; however, its exact mechanism of action remains poorly understood. This study aimed to determine whether 1,25(OH)₂ D₃ can attenuate hepatic steatosis by inducing autophagy.

METHODS

Male C57BL/6 mice fed a high-fat diet (HFD) were injected with 1,25(OH)₂ D₃ for 4 weeks. These mice were given 3-methyladenine (3-MA) to inhibit autophagy. HepG2 cells were preincubated with a free fatty acid (FFA) and then treated with 1,25(OH)₂ D₃ . Vitamin D receptor (VDR) shRNA and autophagy-related 16-like 1 (ATG16L1) siRNA were used for VDR knockdown or ATG16L1 silencing, respectively.

RESULTS

1,25(OH)₂ D₃ diminished HFD-induced liver damage and steatosis, changes accompanied by autophagy and ATG16L1 expression upregulation. Inhibition of 1,25(OH)₂ D₃ -induced autophagy mediated by 3-MA blocked the protective effects of 1,25(OH)₂ D₃ on hepatic steatosis. Additionally, 1,25(OH)₂ D₃ -induced autophagy appeared to play a role in anti-inflammation and lipid metabolism modulation in the liver. In HepG2 cells, 1,25(OH)₂ D₃ reduced lipid accumulation and increased autophagy and ATG16L1 expression; however, this effect was abrogated after VDR knockdown. The protective effects of 1,25(OH)₂ D₃ -mediated autophagy against lipid accumulation were abolished by 3-MA. Furthermore, siRNA-mediated ATG16L1 knockdown prevented 1,25(OH)₂ D₃ -induced autophagy, resulting in increased fat accumulation.

CONCLUSIONS

The data suggest that 1,25(OH)₂ D₃ may ameliorate hepatic steatosis by inducing autophagy by upregulating ATG16L1.

Prenatal and postnatal presentations of corpus callosum agenesis with polymicrogyria caused by EGP5 mutation

EPG5-related Vici syndrome is a rare multisystem autosomal recessive disorder characterized by corpus callosum agenesis (ACC), hypopigmentation, cataracts, acquired microcephaly, failure to thrive, cardiomyopathy and profound developmental delay, and immunodeficiency. We report here the first case of prenatally diagnosed Vici syndrome with delayed gyration associated with ACC. Trio based exome sequencing allowed the identification of a compound heterozygous mutation in the EPG5 gene. Our patient subsequently demonstrated severe developmental delay, hypopigmentation, progressive microcephaly, and failure to thrive which led to suspicion of the diagnosis. Her MRI demonstrated ACC with frontoparietal polymicrogyria, severe hypomyelination, and pontocerebellar atrophy. This prenatal presentation of malformations of cortical development in combination with ACC expands the EPG5-related phenotypic spectrum. Our report supports the idea that EPG5-related Vici syndrome is both a neurodevelopmental and neurodegenerative disorder. © 2017 Wiley Periodicals, Inc.

C9ORF72 and UBQLN2 mutations are causes of amyotrophic lateral sclerosis in New Zealand: a genetic and pathologic study using banked human brain tissue

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, which causes progressive and eventually fatal loss of motor function. Here, we describe genetic and pathologic characterization of brain tissue banked from 19 ALS patients over nearly 20 years at the Department of Anatomy and the Centre for Brain Research, University of Auckland, New Zealand. We screened for mutations in SOD1, TARDBP, FUS, and C9ORF72 genes and for neuropathology caused by phosphorylated TDP-43, dipeptide repeats (DPRs), and ubiquilin. We identified 2 cases with C9ORF72 repeat expansions. Both harbored phosphorylated TDP-43 and DPR inclusions. We show that DPR inclusions can incorporate or occur independently of ubiquilin. We also identified 1 case with a UBQLN2 mutation, which showed phosphorylated TDP-43 and characteristic ubiquilin protein inclusions. This is the first study of ALS genetics in New Zealand, adding New Zealand to the growing list of countries in which C9ORF72 repeat expansion and UBQLN2 mutations are detected in ALS cases.

Non-parametric Survival Analysis of EPG5 Gene with Age at Onset of Alzheimer's Disease

Non-parametric methods such as Wilcoxon test have the advantages of no assumptions for the underlying survival distributions. Alzheimer's disease (AD) is a chronic neurodegenerative disease while the ectopic P-granules autophagy protein 5 homolog (EPG5 gene) is highly expressed in human brain and may implicate in the pathogenesis of neurodegenerative disorders. The present study explored the associations of 26 single-nucleotide polymorphisms (SNPs) in the EPG5 gene with the age at onset (AAO) of AD using a family-based association test (FBAT)-Wilcoxon statistic in a family-based study. Then a replication study using a case-control sample was conducted to perform Wilcoxon test in Kaplan-Meier survival analysis of AAO. The results from FBAT-generalized estimating equations (FBAT-GEE) statistics and FBAT-Wilcoxon test showed that seven SNPs (top SNP rs495078 with p = 1.29 × 10-3) were significantly associated with the risk of AD, and eight SNPs (top SNP rs11082498 with p = 3.55 × 10-4) were associated with the AAO of AD in the family-based study (p < 0.05). In the replicated data, three SNPs were associated with AAO by using the Wilcoxon test, where the mean AAO was approximately 2.2 years earlier in individuals who had at least one minor allele of the top AAO-associated SNP rs9963463 (p = 0.0018) compared with those who were homozygous for the major allele. These findings from non-parametric survival analyses provide evidence for several genetic variants in EPG5 influencing the AAO of AD and will serve as a resource for replication in other populations.

The Vici Syndrome Protein EPG5 Is a Rab7 Effector that Determines the Fusion Specificity of Autophagosomes with Late Endosomes/Lysosomes

Mutations in the human autophagy gene EPG5 cause the multisystem disorder Vici syndrome. Here we demonstrated that EPG5 is a Rab7 effector that determines the fusion specificity of autophagosomes with late endosomes/lysosomes. EPG5 is recruited to late endosomes/lysosomes by direct interaction with Rab7 and the late endosomal/lysosomal R-SNARE VAMP7/8. EPG5 also binds to LC3/LGG-1 (mammalian and C. elegans Atg8 homolog, respectively) and to assembled STX17-SNAP29 Qabc SNARE complexes on autophagosomes. EPG5 stabilizes and facilitates the assembly of STX17-SNAP29-VAMP7/8 trans-SNARE complexes, and promotes STX17-SNAP29-VAMP7-mediated fusion of reconstituted proteoliposomes. Loss of EPG5 activity causes abnormal fusion of autophagosomes with various endocytic vesicles, in part due to elevated assembly of STX17-SNAP25-VAMP8 complexes. SNAP25 knockdown partially suppresses the autophagy defect caused by EPG5 depletion. Our study reveals that EPG5 is a Rab7 effector involved in autophagosome maturation, providing insight into the molecular mechanism underlying Vici syndrome.

UBQLN2 Mediates Autophagy-Independent Protein Aggregate Clearance by the Proteasome

Clearance of misfolded and aggregated proteins is central to cell survival. Here, we describe a new pathway for maintaining protein homeostasis mediated by the proteasome shuttle factor UBQLN2. The 26S proteasome degrades polyubiquitylated substrates by recognizing them through stoichiometrically bound ubiquitin receptors, but substrates are also delivered by reversibly bound shuttles. We aimed to determine why these parallel delivery mechanisms exist and found that UBQLN2 acts with the HSP70-HSP110 disaggregase machinery to clear protein aggregates via the 26S proteasome. UBQLN2 recognizes client-bound HSP70 and links it to the proteasome to allow for the degradation of aggregated and misfolded proteins. We further show that this process is active in the cell nucleus, where another system for aggregate clearance, autophagy, does not act. Finally, we found that mutations in UBQLN2, which lead to neurodegeneration in humans, are defective in chaperone binding, impair aggregate clearance, and cause cognitive deficits in mice.

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UBQLN2 clears aggregates independent of autophagy via HSP70 and the proteasome

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A disease mutation in UBQLN2 prevents its binding to HSP70

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Mutant UBQLN2 is defective in clearance of aggregates in vivo

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UBQLN2 knockin mice develop cognitive impairment and brain pathology

Ursolic acid enhances macrophage autophagy and attenuates atherogenesis

Macrophage autophagy has been shown to be protective against atherosclerosis. We previously discovered that ursolic acid (UA) promoted cancer cell autophagy. In the present study, we aimed to examine whether UA enhances macrophage autophagy in the context of atherogenesis. Cell culture study showed that UA enhanced autophagy of macrophages by increasing the expression of Atg5 and Atg16l1, which led to altered macrophage function. UA reduced pro-interleukin (IL)-1β protein levels and mature IL-1β secretion in macrophages in response to lipopolysaccharide (LPS), without reducing IL-1β mRNA expression. Confocal microscopy showed that in LPS-treated macrophages, UA increased LC3 protein levels and LC3 appeared to colocalize with IL-1β. In cholesterol-loaded macrophages, UA increased cholesterol efflux to apoAI, although it did not alter mRNA or protein levels of ABCA1 and ABCG1. Electron microscopy showed that UA induced lipophagy in acetylated LDL-loaded macrophages, which may result in increased cholesterol ester hydrolysis in autophagolysosomes and presentation of free cholesterol to the cell membrane. In LDLR(-/-) mice fed a Western diet to induce atherogenesis, UA treatment significantly reduced atherosclerotic lesion size, accompanied by increased macrophage autophagy. In conclusion, the data suggest that UA promotes macrophage autophagy and, thereby, suppresses IL-1β secretion, promotes cholesterol efflux, and attenuates atherosclerosis in mice.

Gene-microbiota interactions contribute to the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is associated with risk variants in the human genome and dysbiosis of the gut microbiome, though unifying principles for these findings remain largely undescribed. The human commensal Bacteroides fragilis delivers immunomodulatory molecules to immune cells via secretion of outer membrane vesicles (OMVs). We reveal that OMVs require IBD-associated genes, ATG16L1 and NOD2, to activate a noncanonical autophagy pathway during protection from colitis. ATG16L1-deficient dendritic cells do not induce regulatory T cells (T(regs)) to suppress mucosal inflammation. Immune cells from human subjects with a major risk variant in ATG16L1 are defective in T(reg) responses to OMVs. We propose that polymorphisms in susceptibility genes promote disease through defects in "sensing" protective signals from the microbiome, defining a potentially critical gene-environment etiology for IBD.

Two cases of Vici syndrome associated with Idiopathic Thrombocytopenic Purpura (ITP) with a review of the literature

Vici syndrome is a rare congenital disorder first described in 1988. To date, 31 cases have been reported in the literature. The characteristic features of this syndrome include: agenesis of the corpus callosum, albinism, cardiomyopathy, variable immunodeficiency, cataracts, and myopathy. We report two Hispanic sisters with genetically confirmed Vici syndrome who both developed Idiopathic Thrombocytopenic Purpura. To our knowledge, this is an immunologic process that has been previously undescribed within the phenotype of Vici syndrome and should be added to the spectrum of variable immune dysregulation that can be found in these patients.

Genetic Variation in Autophagy-Related Genes Influences the Risk and Phenotype of Buruli Ulcer

Introduction

Buruli ulcer (BU) is a severe necrotizing human skin disease caused by Mycobacterium ulcerans. Clinically, presentation is a sum of these diverse pathogenic hits subjected to critical immune-regulatory mechanisms. Among them, autophagy has been demonstrated as a cellular process of critical importance. Since microtubules and dynein are affected by mycolactone, the critical pathogenic exotoxin produced by M. ulcerans, cytoskeleton-related changes might potentially impair the autophagic process and impact the risk and progression of infection.

Objective

Genetic variants in the autophagy-related genes NOD2, PARK2 and ATG16L1 has been associated with susceptibility to mycobacterial diseases. Here, we investigated their association with BU risk, its severe phenotypes and its progression to an ulcerative form.

Methods

Genetic variants were genotyped using KASPar chemistry in 208 BU patients (70.2% with an ulcerative form and 28% in severe WHO category 3 phenotype) and 300 healthy endemic controls.

Results

The rs1333955 SNP in PARK2 was significantly associated with increased susceptibility to BU [odds ratio (OR), 1.43; P = 0.05]. In addition, both the rs9302752 and rs2066842 SNPs in NOD2 gee significantly increased the predisposition of patients to develop category 3 (OR, 2.23; P = 0.02; and OR 12.7; P = 0.03, respectively, whereas the rs2241880 SNP in ATG16L1 was found to significantly protect patients from presenting the ulcer phenotype (OR, 0.35; P = 0.02).

Conclusion

Our findings indicate that specific genetic variants in autophagy-related genes influence susceptibility to the development of BU and its progression to severe phenotypes.

Buruli ulcer (BU) is a neglected tropical disease caused by Mycobacterium ulcerans. Because the exact trigger is still under investigation, current treatment options rely mostly on the surgical excision of the affected site. There is therefore a pressing demand for improved risk prediction and tailored treatment as well as for new drug targets. By resorting to the largest case-control study reported to date, we show that genetic variation in the autophagy-related genes NOD2, PARK2 and ATG16L1 influence the risk and course of BU disease. Thus, our results provide crucial insights into the role of autophagy in the pathogenesis of BU.

EPG5-related Vici syndrome: a paradigm of neurodevelopmental disorders with defective autophagy

Vici syndrome is a progressive neurodevelopmental multisystem disorder due to recessive mutations in the key autophagy gene EPG5. We report genetic, clinical, neuroradiological, and neuropathological features of 50 children from 30 families, as well as the neuronal phenotype of EPG5 knock-down in Drosophila melanogaster. We identified 39 different EPG5 mutations, most of them truncating and predicted to result in reduced EPG5 protein. Most mutations were private, but three recurrent mutations (p.Met2242Cysfs*5, p.Arg417*, and p.Gln336Arg) indicated possible founder effects. Presentation was mainly neonatal, with marked hypotonia and feeding difficulties. In addition to the five principal features (callosal agenesis, cataracts, hypopigmentation, cardiomyopathy, and immune dysfunction), we identified three equally consistent features (profound developmental delay, progressive microcephaly, and failure to thrive). The manifestation of all eight of these features has a specificity of 97%, and a sensitivity of 89% for the presence of an EPG5 mutation and will allow informed decisions about genetic testing. Clinical progression was relentless and many children died in infancy. Survival analysis demonstrated a median survival time of 24 months (95% confidence interval 0-49 months), with only a 10th of patients surviving to 5 years of age. Survival outcomes were significantly better in patients with compound heterozygous mutations (P = 0.046), as well as in patients with the recurrent p.Gln336Arg mutation. Acquired microcephaly and regression of skills in long-term survivors suggests a neurodegenerative component superimposed on the principal neurodevelopmental defect. Two-thirds of patients had a severe seizure disorder, placing EPG5 within the rapidly expanding group of genes associated with early-onset epileptic encephalopathies. Consistent neuroradiological features comprised structural abnormalities, in particular callosal agenesis and pontine hypoplasia, delayed myelination and, less frequently, thalamic signal intensity changes evolving over time. Typical muscle biopsy features included fibre size variability, central/internal nuclei, abnormal glycogen storage, presence of autophagic vacuoles and secondary mitochondrial abnormalities. Nerve biopsy performed in one case revealed subtotal absence of myelinated axons. Post-mortem examinations in three patients confirmed neurodevelopmental and neurodegenerative features and multisystem involvement. Finally, downregulation of epg5 (CG14299) in Drosophila resulted in autophagic abnormalities and progressive neurodegeneration. We conclude that EPG5-related Vici syndrome defines a novel group of neurodevelopmental disorders that should be considered in patients with suggestive features in whom mitochondrial, glycogen, or lysosomal storage disorders have been excluded. Neurological progression over time indicates an intriguing link between neurodevelopment and neurodegeneration, also supported by neurodegenerative features in epg5-deficient Drosophila, and recent implication of other autophagy regulators in late-onset neurodegenerative disease.

[Expressions and Clinical Significance of Autophagy-related Genes ATG2B, ATG4D, ATG9B in Breast Carcinoma]

OBJECTIVE

To investigate the expressions and clinical significance of autophagy-related gene 2B (ATG2B), autophagy-related gene 4D (ATG4D), autophagy-related gene 9B (ATG9B) in breast cancer cell lines and breast cancer.

METHODS

Cancer Browser screening was applied to study the differential expressions of ATG2B, ATG4D, ATG9B genes in breast cancer. Quantitative Real-time PCR was used to measure the expressions of these three genes in human breast cancer cell lines (MCF-7, MDA-MB-231, MDA-MB-435S and ZR-75-30) as well as 83 cases of breast cancer samples with paired normal breast tissues. The relationships between the expressions of these genes and clinicopathological characteristics were further analyzed.

RESULTS

Cancer Browser screening found abnormal expressions of ATG2B, ATG4D, ATG9B in breast cancer (P = 0.015, P = 0.028, P = 0.040). All four breast cancer cell lines expressed ATG2B, ATG4D, ATG9B, and the expression of ATG2B, ATG9B was significantly lower than positive control (P < 0.001), but ATG4D expression was higher than positive control (P < 0.001). The expressions of ATG2B, ATG4D, ATG9B in breast cancer were all lower than those in the adjacent normal tissues (P < 0.001, P = 0.031, P < 0.001). Furthermore, the expression of ATG2B was correlated with ER (r = 0.949, P = 0.015), and the expression of ATG4D was related to age (r = -0.449, P = 0.005), the expression of ATG9B was correlated to lymph node metastasis and cytokeratin 5/6 status (r = 0.339, P = 0.043; r = 0.533, P = 0.043).

CONCLUSION

ATG2B, ATG4D, ATG9B genes shows low expressions in breast cancer, which may become new molecular markers for the prognosis of breast cancer.

Vici syndrome: a review

Vici syndrome [OMIM242840] is a severe, recessively inherited congenital disorder characterized by the principal features of callosal agenesis, cataracts, oculocutaneous hypopigmentation, cardiomyopathy, and a combined immunodeficiency. Profound developmental delay, progressive failure to thrive and acquired microcephaly are almost universal, suggesting an evolving (neuro) degenerative component. In most patients there is additional variable multisystem involvement that may affect virtually any organ system, including lungs, thyroid, liver and kidneys. A skeletal myopathy is consistently associated, and characterized by marked fibre type disproportion, increase in internal nuclei, numerous vacuoles, abnormal mitochondria and glycogen storage. Life expectancy is markedly reduced.Vici syndrome is due to recessive mutations in EPG5 on chromosome 18q12.3, encoding ectopic P granules protein 5 (EPG5), a key autophagy regulator in higher organisms. Autophagy is a fundamental cellular degradative pathway conserved throughout evolution with important roles in the removal of defective proteins and organelles, defence against infections and adaptation to changing metabolic demands. Almost 40 EPG mutations have been identified to date, most of them truncating and private to individual families.The differential diagnosis of Vici syndrome includes a number of syndromes with overlapping clinical features, neurological and metabolic disorders with shared CNS abnormalities (in particular callosal agenesis), and primary neuromuscular disorders with a similar muscle biopsy appearance. Vici syndrome is also the most typical example of a novel group of inherited neurometabolic conditions, congenital disorders of autophagy.Management is currently largely supportive and symptomatic but better understanding of the underlying autophagy defect will hopefully inform the development of targeted therapies in future.

Expression of aryl hydrocarbon receptor and ATG16L1 protein in experimental oxazolone-induced colitis in rats

We studied the expression of AhR and ATG16L1 protein in experimental oxazolone-induced colitis in rats and anti-inflammatory action of recombinant antagonist of IL-1 receptors (ARIL-1) and simvastatin. The immunopositive cells were determined using an indirect immunofluorescence technique with using a monoclonal rat antibody. It has been established that development of colitis was accompanied by an increase of total number of ATG16L1-lymphocytes (by 30%, P < 0.05) in lymphoid structures of the colon. However the amount of AhR(+)-lymphocytes has not changed. At the same time has increased the concentration of ATG16L1 protein (by 4-11%, P < 0.05) in immunopositive cells. Administration of simvastatin and ARIL-1 during the development of experimental pathology was accompanied by decrease of total number of AhR(+) (by 24-38%, P < 0.05) and ATG16L1(+)-lymphocytes (by 43% - 2 fold, P < 0.05) in the colon.