-
Molecular Plant Pathology Jul 2024A cell death pathway, ferroptosis, occurs in conidial cells and is critical for formation and function of the infection structure, the appressorium, in the rice blast...
A cell death pathway, ferroptosis, occurs in conidial cells and is critical for formation and function of the infection structure, the appressorium, in the rice blast fungus Magnaporthe oryzae. In this study, we identified an orthologous lysophosphatidic acid acyltransferase (Lpaat) acting at upstream of phosphatidylethanolamines (PEs) biosynthesis and which is required for such fungal ferroptosis and pathogenicity. Two PE species, DOPE and SLPE, that depend on Lpaat function for production were sufficient for induction of lipid peroxidation and the consequent ferroptosis, thus positively regulating fungal pathogenicity. On the other hand, both DOPE and SLPE positively regulated autophagy. Loss of the LPAAT gene led to a decrease in the lipidated form of the autophagy protein Atg8, which is probably responsible for the autophagy defect of the lpaatΔ mutant. GFP-Lpaat was mostly localized on the membrane of lipid droplets (LDs) that were stained by the fluorescent dye monodansylpentane (MDH), suggesting that LDs serve as a source of lipids for membrane PE biosynthesis and probably as a membrane source of autophagosome. Overall, our results reveal novel intracellular membrane-bound organelle dynamics based on Lpaat-mediated lipid metabolism, providing a temporal and spatial link of ferroptosis and autophagy.
Topics: Autophagy; Phosphatidylethanolamines; Ferroptosis; Oryza; Plant Diseases; Fungal Proteins; Acyltransferases; Ascomycota
PubMed: 38956897
DOI: 10.1111/mpp.13489 -
Theriogenology Jun 2024Follicular fluid (FF) is rich in extracellular vesicles (EVs). EVs carries a variety of miRNA involved in regulating follicular development, the function of cells in...
Follicular fluid (FF) is rich in extracellular vesicles (EVs). EVs carries a variety of miRNA involved in regulating follicular development, the function of cells in follicles, primordial follicular formation, follicular recruitment and selection, follicular atresia, oocyte communication, granulosa cells (GCs) function and luteinization and other biological processes of follicular development. Previous studies in our laboratory have shown that bovine follicular fluid (bFF) high density-small extracellular vesicles (HD-sEVs)-miRNA was enriched in autophagy-related pathways. However, the mechanism of bFF EVs carrying miRNA regulating GCs autophagy is not clear. Thus, this study carried out a series of studies on the previous HD-sEVs sequencing data and miR-128-3p contained in bFF HD-sEVs. A total of 38 differentially expressed genes were detected by RNA-Seq after overexpression of miR-128-3p in bovine GCs (bGCs). Through cell transfection, Western blot (WB) and Immunofluorescence (IF), it was proved that overexpression of miR-128-3p could promote the expression of LC3 (microtubule-associated protein I light chain 3), inhibit p62, promote the number of autophagosome, promote the formation of autophagy lysosome and autophagy flow, and activate bGCs autophagy. MiR-128-3p inhibitor significantly inhibited the expression of LC3 and monodansylcadaverine (MDC) in bGCs, and promoted the expression of autophagy substrate p62, indicating that HD-sEVs-miR-128-3p could activate bGCs autophagy. In addition, through double luciferase assay, bioinformatics analysis, WB and RT-qPCR, it was concluded that bFF HD-sEVs-miR-128-3p could target TFEB (transcription factor EB) and FoxO4 (Forkhead box O4) and activate GCs autophagy.
PubMed: 38954995
DOI: 10.1016/j.theriogenology.2024.06.022 -
Methods in Molecular Biology (Clifton,... 2024Autophagy is an intracellular clearance and recycling pathway that delivers different types of cargos to lysosomes for degradation. In recent years, autophagy has...
Autophagy is an intracellular clearance and recycling pathway that delivers different types of cargos to lysosomes for degradation. In recent years, autophagy has attracted considerable medical interest, and many different techniques are being developed to study this process in experimental models such as Dictyostelium. Here we describe the use of different autophagic markers in confocal microscopy, in vivo and also in fixed cells. In particular, we describe the use of the GFP-Atg8-RFP-Atg8ΔG marker and the optimization of the GFP-PgkA cleavage assay to detect small differences in autophagy flux.
Topics: Dictyostelium; Autophagy; Microscopy, Confocal; Green Fluorescent Proteins; Lysosomes; Protozoan Proteins
PubMed: 38954200
DOI: 10.1007/978-1-0716-3894-1_7 -
Autophagy Jul 2024Macroautophagy, simply referred to below as autophagy, is an intracellular degradation system that is highly conserved in eukaryotes. Since the processes involved in...
Macroautophagy, simply referred to below as autophagy, is an intracellular degradation system that is highly conserved in eukaryotes. Since the processes involved in autophagy are accompanied by membrane dynamics, RAB small GTPases, key regulators of membrane trafficking, are generally thought to regulate the membrane dynamics of autophagy. Although more than half of the mammalian RABs have been reported to be involved in canonical and selective autophagy, no consensus has been reached in regard to the role of RABs in mammalian autophagy. Here, we comprehensively analyzed a -knockout (KO) library of MDCK cells to reevaluate the requirement for each RAB isoform in basal and starvation-induced autophagy. The results revealed clear alteration of the MAP1LC3/LC3-II level in only four -KO cells (-KO, -KO, -KO, and -KO cells) and identified RAB14 as a new regulator of autophagy, specifically at the autophagosome maturation step. The autophagy-defective phenotype of two of these -KO cells, -KO and -KO cells, was very mild, but double KO of and caused a severer autophagy-defective phenotype (greater LC3 accumulation than in single-KO cells, indicating an overlapping role of RAB2 and RAB14 during autophagosome maturation. We also found that RAB14 is phylogenetically similar to RAB2 and that it possesses the same properties as RAB2, i.e. autophagosome localization and interaction with the HOPS subunits VPS39 and VPS41. Our findings suggest that RAB2 and RAB14 overlappingly regulate the autophagosome maturation step through recruitment of the HOPS complex to the autophagosome.
PubMed: 38953305
DOI: 10.1080/15548627.2024.2374699 -
Chinese Medical Sciences Journal =... Jul 2024Objective To explore the influence of Linggui Zhugan Decoction (LGZGD) on high glucose induced podocyte autophagy Methods LGZGD containing serum were prepared by...
Objective To explore the influence of Linggui Zhugan Decoction (LGZGD) on high glucose induced podocyte autophagy Methods LGZGD containing serum were prepared by intragastric administation of 4.2 g·kglow dose, 8.4 g·kg (medium dose), and 12.6 g·kg (high dose) LGZGD into SD rats respectively. MPC5 and AB8/13 cells were treated with 60 mmol/L glucose to establish diabetic nephropathy podocyte model in vitro. Podocytes, MPC5 and AB8.13, were divided into control group, high glucose group, low dose LGZGD group, medium dose LGZGD group, and high dose LGZGD group, respectively. For the three LGZGD groups, before LGZGD intervention, podocytes were treated with 60 mmol/L glucose for 3 days. After treated with LGZGD containing serum, cells were collected to analyze cell migration using Transwell assay, proliferation using CCK8, apoptosis and cell cycle using flow cytometry,, autophagosome formation using transmission electron microscopy, and expression levels of Beclin-1, Atg5, LC3II/I, and P62 proteins using western blot.Results Compared with the control group, the proliferation and migration of MPC5 and AB8.13 cells in high glucose group showed slightly decreased, whereas these parameters restored after intervention with low and medium concentrations of LGZGD, with the medium dose LGZGD having the best effect. Flow cytometry analysis showed that the medium dose LGZGD group had a lower apoptosis rate (P < 0.05) and higher survival rate (P > 0.05) compared to the high dose group. High glucose arrested podocytes in G1 phase, whereas LGZGD shifted podocytes from being predominant in G1 phase to increasing into G2. High dose LGZGD significanly reduced increased autophagosome formation due to high glucose in both podocytes (P < 0.05). Western blot analysis showed that Beclin-1, Atg5, LC3Ⅱ/Ⅰ, and P62 expressions were increased in MPC5 cells treated with high glucose, and reversed after adminstration of low and medium doses of LGZGD (P < 0.05). Conclusion LGZGD reduced apoptosis and enhanced autophagy in high glucose treated podocytes via regulating Beclin-1/LC3II/I/Atg5 expression.
PubMed: 38953223
DOI: 10.24920/004330 -
Autophagy Jul 2024In macroautophagy, lysosomes fuse with closed autophagosomes but not with unclosed ones. This is achieved, at least in part, by the temporally regulated recruitment of...
In macroautophagy, lysosomes fuse with closed autophagosomes but not with unclosed ones. This is achieved, at least in part, by the temporally regulated recruitment of the autophagosomal SNARE STX17 (syntaxin 17) to only mature autophagosomes. However, the molecular mechanism by which STX17 recognizes autophagosomal maturation remains unknown. Our recent study revealed that STX17 recruitment is regulated by the electrostatic interaction between the positively charged C-terminal region of STX17 and the autophagosomal membrane, which becomes negatively charged during maturation due to the accumulation of phosphatidylinositol-4-phosphate (PtdIns4P). Here, we propose an electrostatic maturation model of the autophagosome.
PubMed: 38950891
DOI: 10.1080/15548627.2024.2375082 -
Autophagy Jul 2024A growing number of studies link dysfunction of macroautophagy/autophagy to the pathogenesis of diseases such as Alzheimer disease (AD). Given the global importance of...
A growing number of studies link dysfunction of macroautophagy/autophagy to the pathogenesis of diseases such as Alzheimer disease (AD). Given the global importance of autophagy for homeostasis, how its dysfunction can lead to specific neurological changes is puzzling. To examine this further, we compared the global deactivation of autophagy in the adult mouse using the iKO with the impact of AD-associated pathogenic changes in autophagic processing of synaptic proteins. Isolated forebrain synaptosomes, rather than total homogenates, from iKO mice demonstrated accumulation of synaptic proteins, suggesting that the synapse might be a vulnerable site for protein homeostasis disruption. Moreover, the deactivation of autophagy resulted in impaired cognitive performance over time, whereas gross locomotor skills remained intact. Despite deactivation of autophagy for 6.5 weeks, changes in cognition were in the absence of cell death or synapse loss. In the symptomatic APP PSEN1 double-transgenic mouse model of AD, we found that the impairment in autophagosome maturation coupled with diminished presence of discrete synaptic proteins in autophagosomes isolated from these mice, leading to the accumulation of one of these proteins in the detergent insoluble protein fraction. This protein, SLC17A7/Vglut, also accumulated in iKO mouse synaptosomes. Taken together, we conclude that synaptic autophagy plays a role in maintaining protein homeostasis, and that while decreasing autophagy interrupts normal cognitive function, the preservation of locomotion suggests that not all circuits are affected similarly. Our data suggest that the disruption of autophagic activity in AD may have relevance for the cognitive impairment in this adult-onset neurodegenerative disease. : 2dRAWM: 2-day radial arm water maze; AD: Alzheimer disease; Aβ: amyloid-beta; AIF1/Iba1: allograft inflammatory factor 1; APP: amyloid beta precursor protein; ATG7: autophagy related 7; AV: autophagic vacuole; CCV: cargo capture value; Ctrl: control; DLG4/PSD-95: discs large MAGUK scaffold protein 4; GFAP: glial fibrillary acidic protein; GRIN2B/NMDAR2b: glutamate ionotropic receptor NMDA type subunit 2B; LTD: long-term depression; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; m/o: months-old; PNS: post-nuclear supernatant; PSEN1/PS1: presenilin 1; SHB: sucrose homogenization buffer; SLC32A1/Vgat: solute carrier family 32 member 1; SLC17A7/Vglut1: solute carrier family 17 member 7; SNAP25: synaptosome associated protein 25; SQSTM1/p62: sequestosome 1; SYN1: synapsin I; SYP: synaptophysin ; SYT1: synaptotagmin 1; Tam: tamoxifen; VAMP2: vesicle associated membrane protein 2; VCL: vinculin; wks: weeks.
PubMed: 38949671
DOI: 10.1080/15548627.2024.2368335 -
BioRxiv : the Preprint Server For... Jun 2024Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the...
Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the degradation of membranes and internal cargo during both macroautophagy and corpse clearance, raising the question how macroautophagy contributes to corpse clearance. Studying the clearance of non-apoptotic dying polar bodies in embryos, we show that the LC3 ortholog LGG-2 is enriched in the polar body phagolysosome independent of membrane association or autophagosome formation. We demonstrate that ATG-16.1 and ATG-16.2, which promote membrane association of lipidated Atg8/LC3 proteins, redundantly promote polar body membrane breakdown in phagolysosomes independent of their role in macroautophagy. We also show that the lipid scramblase ATG-9 is needed for autophagosome formation in early embryos but is dispensable for timely polar body membrane breakdown or protein cargo degradation. These findings demonstrate that macroautophagy is not required to promote polar body degradation, in contrast to recent findings with apoptotic corpse clearance in embryos. Determining how membrane association of Atg8/LC3 promotes the breakdown of different types of cell corpses in distinct cell types or metabolic states is likely to give insights into the mechanisms of immunoregulation during normal development, physiology, and disease.
PubMed: 38948720
DOI: 10.1101/2024.06.19.599770 -
Theranostics 2024Autophagy dysregulation is known to be a mechanism of doxorubicin (DOX)-induced cardiotoxicity (DIC). Mitochondrial-Endoplasmic Reticulum Contacts (MERCs) are where...
Autophagy dysregulation is known to be a mechanism of doxorubicin (DOX)-induced cardiotoxicity (DIC). Mitochondrial-Endoplasmic Reticulum Contacts (MERCs) are where autophagy initiates and autophagosomes form. However, the role of MERCs in autophagy dysregulation in DIC remains elusive. FUNDC1 is a tethering protein of MERCs. We aim to investigate the effect of DOX on MERCs in cardiomyocytes and explore whether it is involved in the dysregulated autophagy in DIC. We employed confocal microscopy and transmission electron microscopy to assess MERCs structure. Autophagic flux was analyzed using the mCherry-EGFP-LC3B fluorescence assay and western blotting for LC3BII. Mitophagy was studied through the mCherry-EGFP-FIS1 fluorescence assay and colocalization analysis between LC3B and mitochondria. A total dose of 18 mg/kg of doxorubicin was administrated in mice to construct a DIC model . Additionally, we used adeno-associated virus (AAV) to cardiac-specifically overexpress FUNDC1. Cardiac function and remodeling were evaluated by echocardiography and Masson's trichrome staining, respectively. DOX blocked autophagic flux by inhibiting autophagosome biogenesis, which could be attributed to the downregulation of FUNDC1 and disruption of MERCs structures. FUNDC1 overexpression restored the blocked autophagosome biogenesis by maintaining MERCs structure and facilitating ATG5-ATG12/ATG16L1 complex formation without altering mitophagy. Furthermore, FUNDC1 alleviated DOX-induced oxidative stress and cardiomyocytes deaths in an autophagy-dependent manner. Notably, cardiac-specific overexpression of FUNDC1 protected DOX-treated mice against adverse cardiac remodeling and improved cardiac function. : In summary, our study identified that FUNDC1-meditated MERCs exerted a cardioprotective effect against DIC by restoring the blocked autophagosome biogenesis. Importantly, this research reveals a novel role of FUNDC1 in enhancing macroautophagy via restoring MERCs structure and autophagosome biogenesis in the DIC model, beyond its previously known regulatory role as an mitophagy receptor.
Topics: Animals; Doxorubicin; Mice; Autophagy; Cardiotoxicity; Myocytes, Cardiac; Endoplasmic Reticulum; Membrane Proteins; Mitochondrial Proteins; Mitochondria; Mitophagy; Male; Autophagosomes; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 38948070
DOI: 10.7150/thno.92771 -
MedRxiv : the Preprint Server For... Jun 2024Blood-based biomarkers are gaining grounds for Alzheimer's disease (AD) detection. However, two key obstacles need to be addressed: the lack of methods for multi-analyte...
BACKGROUND
Blood-based biomarkers are gaining grounds for Alzheimer's disease (AD) detection. However, two key obstacles need to be addressed: the lack of methods for multi-analyte assessments and the need for markers of neuroinflammation, vascular, and synaptic dysfunction. Here, we evaluated a novel multi-analyte biomarker platform, NULISAseq CNS disease panel, a multiplex NUcleic acid-linked Immuno-Sandwich Assay (NULISA) targeting ∼120 analytes, including classical AD biomarkers and key proteins defining various disease hallmarks.
METHODS
The NULISAseq panel was applied to 176 plasma samples from the MYHAT-NI cohort of cognitively normal participants from an economically underserved region in Western Pennsylvania. Classical AD biomarkers, including p-tau181, p-tau217, p-tau231, GFAP, NEFL, Aβ40, and Aβ42, were also measured using Single Molecule Array (Simoa). Amyloid pathology, tau pathology, and neurodegeneration were evaluated with [11C] PiB PET, [18F]AV-1451 PET, and MRI, respectively. Linear mixed models were used to examine cross-sectional and Wilcoxon rank sum tests for longitudinal associations between NULISA biomarkers and AD pathologies. Spearman correlations were used to compare NULISA and Simoa.
RESULTS
NULISA concurrently measured 116 plasma biomarkers with good technical performance, and good correlation with Simoa measures. Cross-sectionally, p-tau217 was the top hit to identify Aβ pathology, with age, sex, and genotype-adjusted AUC of 0.930 (95%CI: 0.878-0.983). Fourteen markers were significantly decreased in Aβ-PET+ participants, including TIMP3, which regulates brain Aβ production, the neurotrophic factor BDNF, the energy metabolism marker MDH1, and several cytokines. Longitudinally, FGF2, IL4, and IL9 exhibited Aβ PET-dependent yearly increases in Aβ-PET+ participants. Markers with tau PET-dependent longitudinal changes included the microglial activation marker CHIT1, the reactive astrogliosis marker CHI3L1, the synaptic protein NPTX1, and the cerebrovascular markers PGF, PDGFRB, and VEFGA; all previously linked to AD but only reliably measured in cerebrospinal fluid. SQSTM1, the autophagosome cargo protein, exhibited a significant association with neurodegeneration status after adjusting age, sex, and ε4 genotype.
CONCLUSIONS
Together, our results demonstrate the feasibility and potential of immunoassay-based multiplexing to provide a comprehensive view of AD-associated proteomic changes. Further validation of the identified inflammation, synaptic, and vascular markers will be important for establishing disease state markers in asymptomatic AD.
PubMed: 38947065
DOI: 10.1101/2024.06.15.24308975